PP-based talcum powder master batch as well as preparation method and application thereof

Abstract

The invention relates to a PP-based talcum powder master batch as well as a preparation method and application thereof, and belongs to the technical field of development and application of talcum powder master batches. The PP-based talcum powder master batch provided by the invention is prepared from the following components in parts by mass: 15 to 25 parts of metallocene PP, 75 to 85 parts of talcum powder co-modified by a silane coupling agent and hydroxyl silicone oil, 0.3 to 0.6 part of an antioxidant, 0.2 to 0.5 part of a lubricant and 0.2 to 0.5 part of PE wax. The PP-based talcum powder master batch provided by the invention can solve the problems that the PP-based talcum powder master batch in the current market is easy to yellow and the whiteness is reduced in the manufacturing process, improves the problem that the talcum powder master batch has great influence on the impact strength of a modified PP composite material, and meets the application of the PP-based talcum powder master batch in some PP products with higher white quality requirements; and the PP product can maintain high impact performance.

Description

Technical Field

[0001] The invention belongs to the technical field of development and application of talc masterbatch, and specifically relates to a PP-based talc masterbatch and a preparation method and application thereof. Background Art

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

[0003] The preparation method of PP-based talc masterbatch is usually to first use an internal mixer to mix fluffy talc, PP carrier and additives into a rubber block premix, so that the talc is fully infiltrated and dispersed in the PP carrier, and then the rubber block premix is ​​fed into a single screw extruder through a conical double feeder, and extruded and granulated at a certain speed and temperature to obtain PP-based talc masterbatch. However, in industrial production, in order to improve production efficiency, large-scale internal mixers are usually configured. Large-scale internal mixers use pressurized mixing to mix the materials. Since talc is very fluffy and has a large stacking volume, heating only by the bottom of the internal mixer cannot efficiently heat and heat the materials. A pressurized cover is required to compact and mix the materials to achieve material heating and plasticization. The PP carrier is sheared by friction during compaction and mixing, and is easily thermally oxidized under high pressure and heat. In addition, the pressurized mixing cannot be vented in time, resulting in yellowing of the entire kettle material. As a result, the color quality of the talc masterbatch is poor, and the whiteness is greatly reduced, which limits the application of talc masterbatch in high-whiteness quality products. In order to improve the quality problem of PP-based talc masterbatch that is easy to turn yellow during the preparation process, some technical solutions shorten the mixing time in the production of PP-based talc masterbatch, and stop mixing when the material is not fully plasticized. This preparation method uses mixing time to control the plasticization degree of the material, but the effect is not satisfactory. The material is not fully mixed and plasticized, resulting in uneven feeding and unstable production during extrusion granulation. The talc masterbatch has a high breakage rate and an uneven appearance. In addition, after talc and talc masterbatch are modified with PP materials, the rigidity is improved, while the impact performance of the material is also greatly reduced. In particular, after talc is added to high-impact PP, the impact strength often drops from a higher value to a lower value. In response to this problem, the industry usually adds a third component toughening agent to the talc-modified PP composite for toughening modification, but the toughening agent is expensive and has a great impact on the rigidity of the talc-modified PP composite. Patent CN113861554A discloses a high-gloss, well-dispersed polypropylene talc masterbatch and a preparation method thereof, which uses homopolymerized low melt index polypropylene and metallocene low isotactic polypropylene as carriers. However, the melt index of metallocene low isotactic polypropylene (melt index is 2000~2500g / 10min) is too high, and the whiteness of the PP carrier talc masterbatch prepared by pressurized mixing is not guaranteed, and the effect of the talc masterbatch on the impact strength of 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 of 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 and a preparation method and application thereof.

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

[0007] 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.

[0008] 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.

[0009] The present invention further performs co-grafting modification of the preferred talc with a silane coupling agent and hydroxy silicone oil. The silanol on the surface of the silane coupling agent can undergo a condensation reaction with the hydroxyl on the surface of the talc or combine with the original silane ether hydroxyl on the surface, which not only removes moisture from the surface of the talc but also forms a silane ether bond with the oxygen atoms therein, significantly improving the affinity of the talc with PP. The specific chemical grafting process is achieved through the following two steps: first, the silane coupling agent is hydrolyzed to generate silanol, which then undergoes condensation with the hydroxyl on the surface of the talc for grafting; for example, the ethoxy (-OCH 2 CH 3 ) is hydrolyzed under heating conditions to generate silanol (-Si-OH), NH 2 (CH 2 ) 3 Si(OCH 2 CH 3 ) 3 +3H 2 O→NH 2 (CH 2 ) 3 Si(OH) 3 (γ-aminopropyltrihydroxysilane)+3CH 3 CH 2 OH, the hydrolyzed silanol (-Si-OH) then undergoes a condensation reaction with the hydroxyl group (-OH) on the surface of talc to form a Si-O-Si or Si-O-Mg covalent bond and remove the water molecule: NH 2 (CH 2 ) 3Si(OH) 3 +HO–[talc surface] → NH 2 (CH 2 ) 3 Si-O-[talc surface]+H 2 O.

[0010] Hydroxyl silicone oil and the hydroxyl groups on the surface of talc can also undergo similar chemical reactions. The terminal hydroxyl groups of hydroxy silicone oil and the hydroxyl groups on the surface of talc undergo condensation reactions under heating conditions to generate silicon-oxygen bonds, grafting non-polar siloxane structures onto the surface of talc to form active talc, improving the dispersibility and wettability of talc in the PP matrix. In addition, the siloxane structure has the effects of increasing volume, lubrication and toughening, which can improve the problem that talc has a greater impact on the impact properties of PP. The specific chemical grafting process is as follows: Talc (Mg 3 Si 4 O 10 (OH) 2 ) have silicon hydroxyl groups (-Si-OH) and magnesium hydroxyl groups (-Mg-OH) on the surface, which are active sites for the reaction. The terminal hydroxyl groups of hydroxy silicone oil undergo dehydration condensation with the hydroxyl groups (-Si-OH or -Mg-OH) on the surface of talc to form Si-O-Si or Si-O-Mg covalent bonds and release water molecules. After -Si-OH(talc)+HO-[Si(CH 3 ) 2 O] n -H→-Si-O-[Si(CH 3 ) 2 O] n -O-Si-+H 2 O, or -Mg-OH(talc)+HO-[Si(CH 3 ) 2 O] n -H→-Mg-O-[Si(CH 3 ) 2 O] n -O-Mg-+H 2 O reaction.

[0011] The present invention grafts and modifies the talc powder surface through the synergistic compatibility of silane coupling agent and hydroxy silicone oil, significantly improves the dispersibility and interface compatibility of talc powder in PP, accelerates the infiltration and dispersion in the PP carrier, shortens the mixing time, indirectly improves the yellowing effect of the material, and can also improve the impact strength retention rate of talc powder in the modified PP composite.

[0012] Preferably, the metallocene PP has a melting point of 150° C.-160° C. and a melt index of 20 g / 10 min.-100 g / 10 min.

[0013] Specifically, the melting point of the metallocene PP of the present invention is obtained by DSC testing, and the melting index is obtained by testing at 230°C / 2.16kg according to GB / T3682.1-2018.

[0014] The present invention preferably uses metallocene PP with a melting point range of 150° C.-160° C. to prepare talc masterbatch, which can reduce the plasticizing temperature of the banburying and reduce the yellowing of the talc masterbatch caused by excessively high temperature. The metallocene PP has good impact resistance, a narrower molecular weight distribution than ordinary PP, and higher thermal stability. In combination with an antioxidant system, the thermal stability is high in the process, and the yellowing tendency is extremely small. In addition, due to its low processing temperature, the PP-based talc masterbatch can be given a wider processing temperature window, so that the material mixing and dispersion effects are better.

[0015] Preferably, the silane coupling agent and hydroxy silicone oil co-modified talc is obtained by mixing talc, silane coupling agent and hydroxy silicone oil; the amount of the silane coupling agent added is 0.5%-1% of the mass of the talc; the amount of the hydroxy silicone oil added is 0.3%-1% of the mass of the talc.

[0016] Preferably, the talc has a particle size D90 of 8 μm-15 μm (can be tested by a laser particle size analyzer), a whiteness ≥ 90 (tested by a whiteness meter in accordance with GB / T 5950-2008), a silicon dioxide content ≥ 59% (tested in accordance with GB / T15343-2020 talc chemical analysis method), and a calcium oxide content ≤ 4% (tested in accordance with GB / T15343-2020 talc chemical analysis method).

[0017] Since the whiteness test value of talc powder increases as it is ground finer, the present invention has found that talc powder with a particle size within the above range and a whiteness ≥ 90, and talc powder with a silicon dioxide, calcium oxide content, etc. within the above range can make the PP-based talc masterbatch of the present invention have higher performance and whiteness.

[0018] Preferably, the silane coupling agent comprises an aminosilane coupling agent.

[0019] In a specific embodiment of the present invention, the silane coupling agent may be γ-aminopropyltriethoxysilane (KH550).

[0020] Preferably, the hydroxy silicone oil comprises bishydroxy-terminated siloxane.

[0021] Preferably, 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 25-100 mPa·s, and the viscosity of the medium-high-viscosity hydroxy silicone oil is 750-3000 mPa·s.

[0022] More preferably, 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).

[0023] Specifically, the silane coupling agent and hydroxy silicone oil co-modified talc is obtained by mixing talc, silane coupling agent, low-viscosity hydroxy silicone oil and medium-high viscosity hydroxy silicone oil; the amount of the silane coupling agent added is 0.5%-1% of the mass of the talc; the amount of the low-viscosity hydroxy silicone oil added is 0.3%-5% of the mass of the talc; the amount of the medium-high viscosity hydroxy silicone oil added is 0.3%-5% of the mass of the talc.

[0024] 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, a short chain segment, and a high reactivity, but its coating effect on talc is not as good as that of the medium-high viscosity hydroxy silicone oil. The medium-high viscosity hydroxy silicone oil has a longer siloxane chain segment and is not as reactive as the low-viscosity hydroxy silicone oil, but has better flexibility and a better coating effect on talc. Grafting it onto talc can significantly improve the problem that talc has a large influence on the impact properties of modified PP composites, and the impact strength retention rate is high when applied to modified PP composites.

[0025] Preferably, the silane coupling agent and hydroxy silicone oil are preheated before being mixed with the talc for reaction; preheating can improve the reaction activity and the effect of grafting modified talc is more significant.

[0026] Preferably, the antioxidant includes at least one of a thioester antioxidant, a hindered phenol antioxidant, and a phosphite antioxidant.

[0027] More preferably, the antioxidant comprises, by mass percentage, 40%-60% of thioester antioxidant, 10%-30% of hindered phenol antioxidant, and 20%-40% of phosphite antioxidant.

[0028] The combination 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 talc masterbatch.

[0029] In a specific embodiment of the present invention, the antioxidant comprises, by weight, 50% of a thioester antioxidant, 20% of a hindered phenol antioxidant, and 30% of a phosphite antioxidant.

[0030] Preferably, the lubricant includes stearate; specifically, the stearate includes at least one of calcium stearate, zinc stearate and magnesium stearate.

[0031] Preferably, the molecular weight of the PE wax is 1000-3000.

[0032] In a second aspect, the present invention provides a method for preparing the PP-based talc masterbatch, comprising the following steps: (1) uniformly mixing the metallocene PP, antioxidant, lubricant and PE wax according to the mass fractions to obtain a mixture; (2) firstly adding the silane coupling agent and the hydroxy silicone oil co-modified talc into an internal mixer, then adding the mixture obtained in step (1), and mixing to obtain a rubber block premix; (3) The rubber block premix obtained in step (2) is extruded and granulated by a single screw extruder to obtain the PP-based talc masterbatch.

[0033] The preparation method of the PP-based talc masterbatch of the present invention is simple and can be applied to industrial production.

[0034] Preferably, in step (3), the process settings of the single screw extruder are as follows: feed 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 extruder speed is 30 rpm-50 rpm.

[0035] In a third aspect, the present invention provides the use of the PP-based talc masterbatch in the preparation of household appliances, automobiles, and electronic appliances.

[0036] The PP-based talc masterbatch of the present invention is applied to PP, which can make the PP products have high whiteness and high impact strength, and has a wide range of application scenarios, and can be applied to the fields of household appliances, automobiles, electronic appliances, etc.

[0037] Compared with the prior art, the present invention has the following beneficial effects: 1. High whiteness: The high-performance PP-based talc masterbatch of the present invention adopts the talc surface grafting modification technology, and is made into active talc through grafting modification. It can be quickly plasticized and dispersed in the carrier during mixing, shortening the material plasticizing processing time and reducing the possibility of yellowing tendency. In addition, the metallocene PP with low processing temperature is used as the carrier, which has a narrow molecular weight distribution and high thermal stability, and can provide a wider temperature processing window. After compounding with a high-efficiency antioxidant system, the yellowing tendency in the mixing process is extremely small. Therefore, the PP-based talc masterbatch prepared by the technical solution of the present invention has a high whiteness, which is basically equivalent to the whiteness of the PP composite prepared by the original talc powder addition method.

[0038] 2. High performance: The high-performance PP-based talc masterbatch of the present invention adopts silane coupling agent and hydroxy silicone oil to graft-modify talc, so that the talc is modified into active talc, which is easy to infiltrate and disperse in PP, and enhances the interface performance with the PP substrate, improves the ability of the interface with PP to resist impact damage, plays the role of volume expansion and lubrication and toughening. The prepared PP-based talc masterbatch not only has a significant rigidity-enhancing effect in PP, but also significantly improves the problem that talc has a large influence on the impact strength of PP, and improves the impact strength retention rate of PP composites. DETAILED DESCRIPTION

[0039] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be understood by those skilled in the art that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] Unless otherwise specified, the experimental methods used in the examples are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial channels.

[0041] Examples 1-6 The composition of the PP-based talc masterbatch described in the embodiment of the present invention is shown in Table 1.

[0042] The method for preparing the PP-based talc masterbatch comprises the following steps: (1) First, use a low-speed mixer to stir the metallocene PP, antioxidant, lubricant, and PE wax according to the mass fractions shown in Table 1. The stirring speed is 50 rpm and the stirring time is 5 minutes. After the stirring is completed, the mixture is ready to be put into the bottom of the internal mixer; (2) According to the process sequence of first adding talcum powder and then adding PP, first open the feed valve of the talcum powder feeding pipeline to add the modified talcum powder, then open the feed valve of the PP feeding pipeline to add the mixture obtained in step (1), set the bottom temperature of the internal mixer to 170°C, start the internal mixer main engine, the speed is 40 rpm, start the pressure cover to press the material down to mix the material, during the material mixing process, pay attention to observe the material temperature display on the control screen, and control the mixing stop time when the material temperature rises to a certain value. In addition, the pressure cover is lifted to exhaust and repeatedly pressed down 6 times during the whole mixing process, each time at an interval of 1.5 minutes. Under the action of the pressure cover, the material is compacted, plasticized, and mixed into a rubber block premix. When the material temperature display rises to 175°C, the mixing and discharging is stopped to obtain a rubber block premix; (3) pouring the rubber block premix obtained in step (2) into the hopper of the elevator, starting the elevator to feed the rubber block premix into the hopper of the conical double-feeder, feeding the premix into the single-screw extruder through the conical double-feeder, extruding the premix through the die of the single-screw extruder at a certain speed, pelletizing and air cooling through a hot pelletizer, and then conveying and sieving the product through a multi-stage fan to the finished product bin, thereby obtaining the PP-based talc masterbatch.

[0043] The process settings of the single-screw extruder are as follows: feed zone 1 150°C, zone 2 165°C, zone 3 165°C, zone 4 165°C, zone 5 165°C, zone 6 die head 170°C, and the extruder speed is 40 rpm.

[0044] Comparative Examples 1-5 The difference between Comparative Examples 1-5 and the embodiment is only in the types and proportions of components, as shown in Table 1.

[0045] Among the components described in each embodiment and comparative example, The metallocene PP is LG Chemical MH1700, with a melting point (DSC test) of 150°C and a melt index of 40g / 10min (GB / T3682.1-2018, 230°C / 2.16kg); The common PP is homopolymer PP, Shanghai Saike S2040, with a melting point (DSC test) of 165°C and a melt index of 40g / 10min (GB / T3682.1-2018, 230°C / 2.16kg); The modified talc 1 is obtained by mixing talc A, a silane coupling agent, a low-viscosity hydroxy silicone oil, and a medium-high viscosity hydroxy silicone oil; the amount of the silane coupling agent added is 0.7% of the mass of the talc A; the amount of the low-viscosity hydroxy silicone oil added is 0.5% of the mass of the talc A; the amount of the medium-high viscosity hydroxy silicone oil added is 0.5% of the mass of the talc A powder; the talc A is of grade AH-1250N6, with a particle size D90 of 10 μm, a whiteness of 92, a silicon dioxide content of 60%, and a calcium oxide content of 3%, and is produced by Guangxi Huamei Talc Development Co., Ltd.; the silane coupling agent is an aminosilane coupling agent KH550, which is commercially available; the low-viscosity hydroxy silicone oil is Dow Corning PMX-0156, with a viscosity of 100 mPa.s; the medium-high viscosity hydroxy silicone oil is JN203-2000 of Shandong Juneng Chemical Co., Ltd., with a viscosity of 2000 mPa.s; The preparation method of the modified talc 1 specifically comprises the following steps: pouring a silane coupling agent into a container, placing it in a thermostat at 80° C. for preheating for 2 hours, placing a low-viscosity hydroxy silicone oil in a thermostat at 80° C. for preheating for 2 hours using the same method, and placing a medium-high viscosity hydroxy silicone oil in a thermostat at 120° C. for preheating for 2 hours using the same method; then putting talc A into a high-speed mixer according to the output ratio, pouring the preheated silane coupling agent, low-viscosity hydroxy silicone oil and medium-high viscosity hydroxy silicone oil into the high-speed mixer according to the ratio, starting the high-speed mixer, setting the mixing temperature to 120° C., the speed to 900 rpm, the mixing time to 8 minutes, the talc reacts chemically with the above modifiers at a high speed, and the modified talc 1 is obtained after the mixing is completed; The modified talc 2 is obtained by mixing talc A, a silane coupling agent, and a low-viscosity hydroxy silicone oil; the amount of the silane coupling agent added is 0.7% of the mass of the talc A; the amount of the low-viscosity hydroxy silicone oil added is 0.5% of the mass of the talc A. The specific preparation method is referred to the modified talc 1; that is, the difference between the modified talc 2 and the modified talc 1 is that the modified talc 2 is only modified by grafting with a silane coupling agent and a low-viscosity hydroxy silicone oil, and is not modified with a medium- or high-viscosity hydroxy silicone oil; The modified talc 3 is obtained by mixing talc A, a silane coupling agent, and medium-high viscosity hydroxy silicone oil; the amount of the silane coupling agent added is 0.7% of the mass of the talc A; the amount of the medium-high viscosity hydroxy silicone oil added is 0.5% of the mass of the talc A. The specific preparation method is referred to the modified talc 1; that is, the difference between the modified talc 3 and the modified talc 1 is that the modified talc 3 is only modified by grafting with a silane coupling agent and medium-high viscosity hydroxy silicone oil, and is not modified with a low-viscosity hydroxy silicone oil; The modified talc powder 4 is obtained by mixing talc powder A and a silane coupling agent; the amount of the silane coupling agent added is 0.7% of the mass of the talc powder A, and the specific preparation method is referred to the modified talc powder 1; that is, the difference between the modified talc powder 4 and the modified talc powder 1 is that the modified talc powder 4 is only modified by grafting with a silane coupling agent, and is not modified with low-viscosity hydroxyl silicone oil and medium-high-viscosity hydroxyl silicone oil; The modified talc 5 is obtained by mixing talc A, low-viscosity hydroxy silicone oil, and medium-high viscosity hydroxy silicone oil; the amount of the low-viscosity hydroxy silicone oil added is 0.5% of the mass of the talc A; the amount of the medium-high viscosity hydroxy silicone oil added is 0.5% of the mass of the talc A. The specific preparation method refers to the modified talc 1; that is, the difference between the modified talc 5 and the modified talc 1 is that the modified talc 5 is only modified by grafting low-viscosity and medium-high viscosity hydroxy silicone oils, and no silane coupling agent modification is performed; 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%, and is produced by Guangxi Huamei Talc Powder Development Co., Ltd.; that is, the only difference between the talcum powder B and the talcum powder A is that the silicon dioxide content of the talcum powder B is lower than that of the talcum powder A, and the calcium oxide content is higher than that of the talcum powder A; The antioxidant A is a mixture of antioxidant TH-412S (thioester auxiliary antioxidant), antioxidant 1010 (hindered phenol antioxidant), and antioxidant 168 (phosphite), and the compounding ratio is 50%: 20%: 30% respectively; The antioxidant B is a mixture of antioxidant 1010 (hindered phenol antioxidant) and antioxidant 168 (phosphite), and the compounding ratio is 50%:50% respectively; The lubricant is calcium stearate, which is commercially available; The PE wax has a number average molecular weight of 2000 and is commercially available; Unless otherwise specified, the components and raw materials used in the embodiments and comparative examples of the present invention are all commercially available raw materials, and the components and raw materials used in each parallel experiment are all of the same kind.

[0046] Table 1 Content of each component in the materials of the embodiments and comparative examples (parts) The PP-based talc masterbatch prepared in the embodiment and the comparative example and the talc masterbatch of reference products 1 and 2 were added to PP (Yanshan Petrochemical K7726) resin at a ratio of 25%, mixed evenly, and a talc-modified PP composite was prepared by a twin-screw extruder; the reference product 1 was: talc masterbatch 1, PP carrier, talc content 80%, talc particle size D90 equal to 10 μm, silicon dioxide content 60%, and produced in Guangxi; the reference product 2 was: talc masterbatch 2, PP carrier, talc content 80%; talc particle size D90 equal to 9 μm, silicon dioxide content 61%, and produced in Suzhou.

[0047] The talc powder A (grade AH-1250N6) used in the example was added to PP (Yanshan Petrochemical K7726) by the powder addition method at a ratio of 20%, and a talc powder-modified PP composite was prepared by the same processing technology as a powder-modified PP composite.

[0048] The prepared talc-modified PP composites and pure PP resin (Yanshan Petrochemical K7726) were injected with color plates, bending test specimens and impact test specimens by injection molding machines. The test specimens were placed in a constant temperature chamber at 23℃ for 24 hours and then tested to characterize the application effect of various talc masterbatches in modified PP. The color Lab value of each sample color plate was detected by a colorimeter, where the color L value is used to characterize whiteness. The higher the L value, the higher the whiteness; the color b value is used to characterize the yellow phase. The higher the b value, the more yellow it is, and the lower the b value, the bluer it is. The bending properties were tested using a universal tensile machine in accordance with GB / T9341-2008. The bending modulus index can characterize the rigidity of the material. The notched cantilever beam impact strength of each sample at room temperature (23℃) was tested using a pendulum impact tester in accordance with GB / T1843-2008.

[0049] The test results are shown in Table 2.

[0050] Table 2 Performance test results of composite materials of embodiments, comparative examples and reference products As can be seen from Table 2, the talc masterbatch prepared in Examples 1-3 has a high color L value and a low b value in PP, indicating that the white quality is better and the yellowing tendency of the base color is extremely small, which is basically equivalent to the color quality of the modified PP composite prepared by the talc powder addition method, indicating that the white quality of the talc masterbatch of the present invention is almost the same as that of the original talc. Examples 4-5 are talc modified by a single viscosity hydroxy silicone oil compounded with a silane coupling agent, and the impact strength retention rate of the prepared PP composite is not as good as that of Examples 1-3; the antioxidant in Example 6 is a compound of antioxidant 1010 and antioxidant 168, and the yellowing tendency in the process is higher than that of the antioxidant system of Examples 1-5.

[0051] Comparative Example 1 uses ordinary PP as a carrier, which has a higher melting point than metallocene PP. Its processing temperature window from melting to material mixing is narrower than that of metallocene PP, and the mixing and dispersion effects of the material are not as good as those of metallocene PP. The prepared talc masterbatch is applied to talc PP composites, and the color b value is higher than that of the embodiment, and the impact strength is lower than that of the embodiment.

[0052] Comparative Example 2 uses the same talc powder as the example, but the talc powder has not been surface-grafted and modified. The yellowing tendency of the material during the manufacturing process is higher than that of the modified talc powder. In addition, the impact strength of the modified PP composite material without surface-grafting modification is lower.

[0053] Comparative Example 3 uses ordinary talcum powder, which has a lower silicon dioxide content and a higher calcium oxide content, and has not undergone surface grafting modification. The material has a higher tendency to yellow than that of Example and Comparative Example 2, and the impact strength of the modified PP composite without surface grafting modification is lower than that of Example and Comparative Example 2.

[0054] In Comparative Example 4, only a single silane coupling agent was used to modify talc powder, and the prepared talc powder masterbatch was applied to the modified PP composite. The impact strength of the material was not as good as the talc powder masterbatch made of talc powder co-modified with silane coupling and hydroxy silicone oil.

[0055] Comparative Example 5 uses only talc modified with hydroxy silicone oil, and the prepared talc masterbatch is applied to the modified PP composite. The impact strength of the material is also not as good as the talc masterbatch made of talc co-modified with silane coupling agent and hydroxy silicone oil.

[0056] Reference products 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 their impact strength retention rate when applied to modified PP composites is low.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A PP-based talc masterbatch, characterized in that: The composition comprises the following components by weight: 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 and 0.2-0.5 parts of PE wax.

2. The PP-based talc masterbatch according to claim 1, characterized in that: The metallocene PP has a melting point of 150° C.-160° C. and a melt index of 20 g / 10 min.-100 g / 10 min.

3. The PP-based talc masterbatch according to claim 1, characterized in that: The silane coupling agent and hydroxy silicone oil co-modified talc is obtained by mixing talc, silane coupling agent and hydroxy silicone oil; the added amount of the silane coupling agent is 0.5%-1% of the mass of the talc; the added amount of the hydroxy silicone oil is 0.3%-1% of the mass of the talc.

4. The PP-based talc masterbatch according to claim 3, characterized in that: The talcum powder has a particle size D90 of 8 μm-15 μm, a whiteness ≥90, a silicon dioxide content ≥59%, and a calcium oxide content ≤4%; and / or, the silane coupling agent includes an aminosilane coupling agent; and / or, the hydroxy silicone oil includes a dihydroxy-terminated siloxane.

5. The PP-based talc masterbatch according to claim 3, 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 25-100 mPa·s; the viscosity of the medium-high-viscosity hydroxy silicone oil is 750-3000 mPa·s.

6. The PP-based talc masterbatch according to claim 3, 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).

7. The PP-based talc masterbatch according to claim 1, characterized in that: The antioxidant includes at least one of a thioester antioxidant, a hindered phenol antioxidant, and a phosphite antioxidant; and / or the lubricant includes stearate; and / or the molecular weight of the PE wax is 1000-3000.

8. The PP-based talc masterbatch according to claim 1, characterized in that: The antioxidants include, by weight, 40%-60% of thioester antioxidants, 10%-30% of hindered phenol antioxidants, and 20%-40% of phosphite antioxidants.

9. A method for preparing a PP-based talc masterbatch according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) uniformly mixing the metallocene PP, antioxidant, lubricant and PE wax according to the mass proportions to obtain a mixture; (2) firstly adding the silane coupling agent and the hydroxy silicone oil co-modified talc into an internal mixer, then adding the mixture obtained in step (1), and mixing to obtain a rubber block premix; (3) The rubber block premix obtained in step (2) is extruded and granulated by a single screw extruder to obtain the PP-based talc masterbatch.

10. Use of the PP-based talc masterbatch according to any one of claims 1 to 8 in the preparation of household appliances, automobiles, and electronic appliances.

Images