Polypropylene composition and preparation method therefor and use thereof

Abstract

The present application relates to the technical field of polymer materials, and discloses a polypropylene composition and a preparation method therefor and a use thereof. The product comprises 59-71 parts of a polypropylene resin, 20-40 parts of a modified glass fiber, 1-5 parts of a compatibilizer, 2-5 parts of a micron-scale inorganic substance, and 0.5-3 parts of a nano-scale inorganic opacifying agent. By modifying a glass fiber comprised in the product and defining the retained length of the modified glass fiber, and by introducing two inorganic components having a synergistic effect with the glass fiber, the product can achieve excellent resistance to an alkaline and damp-heat environment and appearance stability simply under the action of three inorganic materials, without the need to introduce special environmental-resistant reagents or modification processes.

Description

Polypropylene composition and preparation method and application thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a polypropylene composition and a preparation method and application thereof. BACKGROUND

[0002] Glass fiber reinforced polypropylene has the advantages of non-toxicity, light weight, easy processing and good mechanical properties, and has been widely used in washing appliances such as dishwashers and washing machines. However, the current use performance of glass fiber reinforced polypropylene in this field still needs to be improved according to feedback. The main reason is that polypropylene is easily catalyzed by external factors due to its unstable structure, and washing appliances need to be used in a hot and humid environment containing washing reagents for a long time. The degradation of polypropylene in this environment is more serious, and the resistance of glass fibers in the product to organic reagents, especially to alkaline reagents, is also poor, which ultimately leads to a serious decline in the integrity and appearance performance of the product.

[0003] In order to improve the service life of glass fiber reinforced polypropylene material in a hot and humid environment, various environmental reagent resistant agents such as antioxidants and light stabilizers are introduced into the product. The initial stability of these modified products in a hot and humid organic environment is significantly improved, but as the environmental reagent resistant agents hydrolyze, migrate and consume, the environmental resistance of the product will also decrease significantly. Some anti-aging additives will generate colored groups after hydrolysis, further affecting the appearance of the product and the user experience. Using high-performance and high-stability environmental reagent resistant agents or modifying the polypropylene matrix resin will greatly increase the production cost of the product. SUMMARY

[0004] The present application provides a polypropylene composition. The product is modified by modifying the glass fibers contained therein and limiting the retention length thereof, and two inorganic components having a synergistic effect with glass fibers are introduced, so that the product can achieve excellent alkaline resistance to a hot and humid environment and appearance stability only under the action of three inorganic materials without the need to introduce special environmental reagent resistant agents or modification processes.

[0005] The technical scheme adopted by the present application is as follows:

[0006] A polypropylene composition, comprising the following components in parts by weight: polypropylene resin 59-71 parts, modified glass fiber 20-40 parts, compatibilizer 1-5 parts, micron-sized inorganic material 2-5 parts, and nanometer-sized inorganic light shielding agent 0.5-3 parts.

[0007] The modified glass fiber is a glass fiber modified by a modified liquid containing phosphate and sulfonic acid, and the retention length thereof is 300-360 microns.

[0008] The average particle size of the micrometer-sized inorganic substance is ≤ 6 μm.

[0009] The nanometer-sized inorganic sunscreen agent comprises nanometer-sized titanium dioxide.

[0010] In some embodiments, the micrometer-sized inorganic substance comprises at least one of micrometer-sized calcium carbonate, micrometer-sized silicate minerals.

[0011] In some embodiments, the silicate minerals comprise at least one of talcum powder, montmorillonite, kaolin, sepiolite, mica.

[0012] In some embodiments, the average particle size of the micrometer-sized inorganic substance is 2-6 μm.

[0013] In some embodiments, the average particle size of the micrometer-sized inorganic substance is 2.5-4 μm.

[0014] In some embodiments, the average particle size of the nanometer-sized inorganic sunscreen agent is 100-300 nm.

[0015] In some embodiments, the phosphate ester is a fatty alcohol phosphate ester; the sulfonic acid is a mixture of dodecylbenzenesulfonic acid and sodium secondary alkyl sulfonate.

[0016] In some embodiments, the polypropylene resin has a melt flow rate of 20-150 g / 10 min at 230℃ under a load of 2.16 kg according to ISO 1133-2011.

[0017] In some embodiments, the polypropylene composition further comprises 0-1 parts by weight of a processing aid.

[0018] In some embodiments, the processing aid comprises at least one of an antioxidant and a lubricant.

[0019] The application also provides a preparation method of the polypropylene composition, comprising the following steps: adding the components into a screw extruder for melt extrusion granulation, thereby obtaining the polypropylene composition.

[0020] The application also provides use of the polypropylene composition in the preparation of a washing appliance.

[0021] The application has the beneficial effect that the application provides a polypropylene composition, which realizes excellent alkali-resistant humid heat environment performance and appearance stability under the action of only three inorganic materials by modifying the glass fiber contained therein and limiting the retention length thereof, and simultaneously introducing two inorganic components having a synergistic effect with the glass fiber. DETAILED DESCRIPTION

[0022] The application provides a polypropylene composition, which comprises the following components by weight:

[0023] polypropylene resin 59-71 parts, modified glass fiber 20-40 parts, compatibilizer 1-5 parts, micron-sized inorganic substance 2-5 parts, and nanometer-sized inorganic sunscreen 0.5-3 parts;

[0024] The modified glass fiber is a glass fiber modified by a modified liquid comprising a phosphate and a sulfonic acid, and has a retention length of 250-350 μm.

[0025] The micron-sized inorganic substance has an average particle size of ≤6 μm.

[0026] The nanometer-sized inorganic sunscreen comprises nanometer-sized titanium dioxide.

[0027] In some embodiments, the retention length of the modified glass fiber is the arithmetic average of the actual length of the modified glass fiber in the polypropylene composition (i.e. the number average length). The retention length described herein can be determined by using conventional methods in the art.

[0028] In some embodiments, the retention length of the modified glass fiber is determined by first burning the polypropylene composition or product at a high temperature of 650 °C for 30 min to remove the resin matrix and retain the inorganic substance, then screening the glass fiber by ultrasonic treatment, uniformly dispersing the glass fiber in water, and determining the retention length of the glass fiber by using a two-dimensional meter.

[0029] In the prior art, the public generally only pay attention to the influence of the original length of the glass fiber used in the preparation of the glass fiber reinforced polypropylene product on the processing performance and the performance of the product after processing, but ignore the fact that the glass fiber will be subjected to mechanical action with the matrix resin and various solid components during the processing of the product, and the glass fiber will be further extruded and rubbed by the matrix resin and the solid components. The product of a glass fiber reinforced system with weak interfacial action is prone to interfacial debonding and obvious floating fiber phenomenon, which not only exposes part of the glass fiber to the outside to some extent, but also deteriorates the heat-oxidative aging performance of the product. On the one hand, it accelerates the erosion of the glass fiber by the external environment, and on the other hand, it also accelerates the penetration of external oxygen due to the weak interfacial action, accelerates the oxidative damage of the resin, and causes serious discoloration of the product.

[0030] To this end, in the technical solution of the present application, in the glass fiber reinforced polypropylene resin system, the modified glass fiber is modified in advance by phosphoric acid ester and sulfonic acid to improve the solvent resistance of the product, especially the alkali resistance, and weaken the erosion of the product in the organic solvent environment. At the same time, two specific contents of inorganic particles of different sizes are introduced to compound and control the actual retention length of the modified glass fiber in the product. The specific size of the inorganic substance can weaken the interface defects between the glass fiber and the polypropylene resin, and also has a similar effect of nucleating agent, so that the crystallinity of the polypropylene resin is improved, the density is improved, the resistance to permeation of external solvents is increased, and the product can achieve ideal extraction resistance effect. The nano-sized inorganic sunscreen containing nano-sized titanium dioxide can improve the dispersion uniformity in the resin matrix based on the mechanical effect, and improve the surface fiber floating phenomenon. In addition, the nano-sized titanium dioxide has high whiteness and strong shielding property to yellow band, which can cover the color change phenomenon of the product in the alkaline environment to a certain extent from the visual effect, so that the product shows excellent appearance stability in the hot and humid environment, especially in the alkaline and hot and humid environment. However, the introduction of nano-sized titanium dioxide will reduce the initial heat-oxidative aging resistance of the product to a certain extent, so it cannot be introduced too much. At the same time, if too much is introduced, the resin wrapping degree of the glass fiber will be weakened due to the excessive force, and then the extraction resistance performance will also be reduced.

[0031] In some embodiments, the polypropylene composition comprises the following components by weight: polypropylene resin 60-65 parts, modified glass fiber 25-35 parts, compatibilizer 2-4 parts, micron-sized inorganic substance 2-5 parts, and nano-sized inorganic sunscreen 0.5-3 parts.

[0032] In some embodiments, the mass content of the polypropylene resin in the polypropylene composition is not less than 50wt%.

[0033] In some embodiments, the micron-sized inorganic substance comprises at least one of micron-sized calcium carbonate and micron-sized silicate mineral. In some embodiments, the silicate mineral comprises at least one of talc, montmorillonite, kaolin, sepiolite and mica.

[0034] In some embodiments, the average particle size of the micron-sized inorganic substance is 2-6μm.

[0035] In some embodiments, the average particle size of the micron-sized inorganic substance is one of 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 5.5μm, 6μm or a range value of any two of them.

[0036] The size of the inorganic substance is larger than that of the nano-sized inorganic light shielding agent. In addition to the grading effect with the nano-sized inorganic light shielding agent to avoid particle agglomeration, as described above, if the size exceeds the defined size, the inorganic substance will not be able to act as a nucleating agent to induce crystallization and increase the compactness of polypropylene, and the alkali resistance and extraction resistance will be significantly reduced.

[0037] In some embodiments, the average particle size of the micro-sized inorganic substance is 2.5-4 μm.

[0038] When in the range, the dispersion of the micro-sized inorganic substance in the product is better, whether it is synergistic with the inorganic ingredients or modification of the polypropylene resin is better, and thus the alkali wet heat environment stability of the product is better.

[0039] In some embodiments, the average particle size of the nano-sized inorganic light shielding agent is 100-300 nm.

[0040] In some embodiments, the average particle size of the nano-sized inorganic light shielding agent is one of 100 nm, 120 nm, 140 nm, 150 nm, 180 nm, 200 nm, 220 nm, 250 nm, 280 nm, 290 nm, 300 nm or a range value of any two thereof.

[0041] In some embodiments, the average particle size of the nano-sized inorganic light shielding agent is 180-250 nm.

[0042] The average particle size of the micro-sized inorganic substance and the nano-sized inorganic light shielding agent in the polypropylene composition described in the present application is tested by using conventional test methods in the art. In some embodiments, the test method for the average particle size is as follows: the average particle size (i.e. the number average particle size, the arithmetic average value of the average particle size) of the commercially available or ground or sieved micro-sized inorganic substance and nano-sized inorganic light shielding agent is obtained by particle size testing according to the GB / T 19077.1-2008 "Particle Size Analysis-Laser Diffraction Method" standard. Although the micro-sized inorganic substance and the nano-sized inorganic light shielding agent belong to inorganic fillers commonly added in polypropylene products in terms of raw material types, in the technical solution of the present application, the mechanism of action of the two on the glass fiber and the polypropylene resin in the product is different from the conventional selection. After modification by phosphoric acid ester substances and sulfonic acid substances, the properly graded inorganic fillers have better compatibility and dispersion effects for the glass fiber in the resin matrix, and will not cause particle agglomeration or glass fiber breakage, nor will it affect the coating effect of the polypropylene resin on the glass fiber and the white shielding effect of the inorganic light shielding agent.

[0043] In some embodiments, the phosphoric acid ester substance is a fatty alcohol phosphoric acid ester.

[0044] In some embodiments, the fatty alcohol phosphate ester is a mixture of fatty alcohol polyoxyethylene ether phosphate ester, lauryl phosphate ester;

[0045] In some embodiments, the sulfonic acid substance is a mixture of dodecyl benzene sulfonic acid, sodium secondary alkyl sulfonate.

[0046] Different modified substances have different effects on the compatibility of glass fiber in polypropylene resin and the improvement of the resistance of glass fiber to the external environment. After the modification of glass fiber by the above-mentioned phosphate ester substance and sulfonic acid substance, the compatibility of glass fiber in polypropylene resin is not weakened, and the other components in the product are not inhibited, and the alkali resistance of glass fiber is significantly improved, and the influence of the external environment on the product is significantly reduced.

[0047] In some embodiments, the modified glass fiber is obtained by immersing glass fiber in a modification solution containing a phosphate ester substance and a sulfonic acid substance.

[0048] In some embodiments, the temperature during the immersion is room temperature, and the time during the immersion is 40-80 s.

[0049] In some embodiments, during the immersion process, the solid-liquid ratio of the glass fiber to the solution is 1 g:(10-200) mL.

[0050] In some embodiments, during the immersion process, stirring is not required. In some embodiments, after the immersion, solid-liquid separation and drying are performed to obtain the modified glass fiber.

[0051] In some embodiments, the modification solution containing a phosphate ester substance and a sulfonic acid substance includes the following components by weight: fatty alcohol polyoxyethylene ether phosphate ester 15-25 parts, lauryl phosphate ester 3-8 parts, dodecyl benzene sulfonic acid 1-3 parts, and sodium secondary alkyl sulfonate 3-8 parts.

[0052] In some embodiments, the modification solution containing a phosphate ester substance and a sulfonic acid substance further includes the following components by weight: organosiloxane defoaming agent 0.1-1 part, epoxy compound hydrolysis stabilizer 0.8-1.2 parts, amino silane coupling agent 0.4-0.8 parts, and epoxy emulsion 2.5-3.5 parts.

[0053] It can be understood that the solvent of the modification solution is water, and the weight fraction of water can be selected conventionally according to actual conditions, without additional limitation.

[0054] It should be noted that the skilled in the art can modify the glass fiber by using the above-mentioned impregnation method and the solution of the above-mentioned formula according to the actual production needs, or modify the glass fiber by using other methods or solutions of other formulae. For example, in order to improve the modification efficiency of the glass fiber, the skilled in the art can use spraying, atomization and other methods to directly adhere the solution containing the phosphate ester and the sulfonic acid to the surface of the glass fiber. In order to improve the uniformity and processability during impregnation, the skilled in the art can additionally add 0.1-1 parts of processing aids such as organosiloxane defoaming agent, 0.8-1.2 parts of hydrolysis stabilizer, etc. to the solution, as long as the expected effect of the product is not affected.

[0055] In some embodiments, the epoxy compound hydrolysis stabilizer comprises 1,1,2,2-tetrakis(p-hydroxyphenyl)ethane tetraglycidyl ether epoxy resin.

[0056] In some embodiments, the amino silane coupling agent comprises γ-aminopropyl triethoxysilane.

[0057] In some embodiments, the epoxy emulsion is an aqueous epoxy emulsion. The "epoxy emulsion" in the present application is understood in its usual definition, i.e. a dispersion system in which an epoxy resin is stably dispersed in the form of microdroplets in a liquid phase (e.g. an aqueous phase).

[0058] The present application does not have special requirements for the compatibilizer, which can be selected by the skilled in the art within the conventional range of the compatibilizer. In some embodiments, the compatibilizer is maleic anhydride grafted polypropylene, and the grafting rate is 1-1.5%. The "grafting rate" in the present application is understood in its usual definition, i.e. the percentage of the mass of the grafted monomer in the total mass of the grafted polymer in the graft copolymer.

[0059] In some embodiments, the polypropylene resin has a melt flow rate of 20-150 g / 10 min at 230°C under a load of 2.16 kg according to ISO 1133-2011.

[0060] In some embodiments, the polypropylene resin has a melt flow rate of one or any two of 20 g / 10 min, 30 g / 10 min, 40 g / 10 min, 50 g / 10 min, 80 g / 10 min, 100 g / 10 min, 120 g / 10 min, 150 g / 10 min at 230°C under a load of 2.16 kg.

[0061] In some embodiments, the polypropylene composition further comprises 0-1 parts by weight of a processing aid in the components.

[0062] In some embodiments, the processing aid includes, but is not limited to, at least one of an antioxidant, a lubricant.

[0063] In some embodiments, the antioxidant includes at least one of a hindered phenolic antioxidant, a phosphite antioxidant, a sulfur antioxidant. In some embodiments, the antioxidant is a mixture of the three of the hindered phenolic antioxidant, the phosphite antioxidant, the sulfur antioxidant, in a mass ratio of (0.8-1.2):(1.8-2.2):(0.8-1.2).

[0064] In some embodiments, the lubricant includes at least one of an EBS amide, a PE wax, a stearate, and a pentaerythritol stearate.

[0065] It is well known to those skilled in the art that, when preparing a polypropylene composition, some common processing aids, such as antioxidants, lubricants, antistatic agents, etc., can be added to the product to improve the processing efficiency, the oxidation resistance and the antistatic property during use, in consideration of their processing effects and subsequent use requirements. However, due to the special filler modification system in the product described in the present application, the resistance of the product to alkaline and humid heat environment is significantly improved. Even if an antioxidant component that can generate a chromophore group is introduced, the migration and consumption of the antioxidant can be significantly inhibited based on the compactness and structural stability of the overall resin, thereby ensuring the appearance stability of the product. The introduction of other processing aids other than the above-mentioned is not limited as long as it does not affect the intended effect of the product.

[0066] The polypropylene composition described in the art can be prepared based on its components and weight parts using conventional methods in the art. In some embodiments, the present application also provides a preparation method of the polypropylene composition, which comprises the following steps: adding the components into a screw extruder for melt extrusion granulation, thereby obtaining the polypropylene composition.

[0067] In some embodiments, the temperature zones of the twin-screw extruder are set to a first zone of 110-130°C, a second zone of 210-230°C, a third zone of 210-230°C, a fourth zone of 210-230°C, a fifth zone of 210-230°C, a sixth zone of 210-230°C, a seventh zone of 210-230°C, an eighth zone of 210-230°C, a ninth zone of 210-230°C, a tenth zone of 210-230°C, a screw rotation speed of 400-500 rpm, and a screw length-diameter ratio of (38-42): 1.

[0068] The present application also provides the use of the polypropylene composition in the preparation of a washing appliance.

[0069] In some embodiments, the present application provides a washing appliance derived from (or made from, or formed from) a material comprising the polypropylene composition. The term "derived" (or "made", or "formed") means that it can be obtained by various processes, including but not limited to molding, such as injection molding, compression molding, blow molding, rotational molding; extrusion, such as sheet extrusion, film extrusion (such as blown-film extrusion); thermoforming; vacuum forming; and melt-blown process.

[0070] In some embodiments, the material comprising the polypropylene composition is derived from (or made from, or formed from) a component (such as a housing 、 base, door frame, spray arm, bowl basket, basket, internal support, drain plate, inner tub, etc.) of a washing appliance (such as a dishwasher, a washing machine, a dryer, etc.).

[0071] In some embodiments, the material comprising the polypropylene composition does not undergo chemical change (i.e., the washing appliance (such as a component of the washing appliance) comprises the polypropylene composition) during the process of deriving (or making, or forming) the washing appliance (such as a component of the washing appliance); or undergoes chemical change.

[0072] In some embodiments, the material comprising the polypropylene composition comprises other substances (such as weathering agent, lubricant, antioxidant, toner, and flaky inorganic particles, etc.) in addition to the polypropylene composition; or does not comprise other substances.

[0073] The polypropylene composition described in the present application has the advantages of easy availability of raw materials, simple production process, high production cost performance, strong appearance stability, long service life, high resistance to solvent environment, especially alkaline and wet-heat solvent environment. After being continuously soaked in an alkaline solution at 70℃ for 40 days, the product can maintain a powdering area ratio of not more than 5% after being statically placed at 150℃ for more than 1000h, showing extremely high stability to alkaline and wet-heat environment, and is very suitable for the preparation of plastic parts of washing appliances which need to directly contact with corrosive detergents (most of which are alkaline) and have certain heating scenarios.

[0074] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in conjunction with specific examples and comparative examples, which are intended to provide a detailed understanding of the content of the present application, rather than limiting the present application. All other examples obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present application. The experimental reagents and instruments involved in the implementation of the present application are all common ordinary reagents and instruments unless otherwise specified.

[0075] Examples 1-13

[0076] An embodiment of the polypropylene composition, the preparation method and the application thereof described in the present application, the composition of the polypropylene composition is shown in Table 1.

[0077] The preparation method of the polypropylene composition comprises the following steps:

[0078] After the components are uniformly mixed and then melt-extruded and granulated in a screw extruder, the polypropylene composition is obtained.

[0079] When the components are melt-extruded, the temperature zones of the screw extruder are set as Zone 1 120℃, Zone 2 220℃, Zone 3 220℃, Zone 4 210℃, Zone 5 210℃, Zone 6 210℃, Zone 7 210℃, Zone 8 210℃, Zone 9 210℃, Zone 10 210℃, the screw rotation speed is 400-500 rpm, and the screw length-diameter ratio is 40:1.

[0080] Comparative Examples 1-12

[0081] The difference between each comparative example and example is only in the type and ratio of components, as shown in Table 2.

[0082] Comparative Example 13

[0083] The difference between Comparative Example 13 and Example 1 is only in the screw rotation speed during processing, which is 300-400 rpm, resulting in different retention lengths of glass fibers in the prepared product.

[0084] In the components of each example and comparative example,

[0085] The polypropylene resin is PP Z30S produced by Sinopec, and the melt flow rate under a load of 2.16 kg at 230℃ according to ISO 1133-2011 is 24.76 g / 10 min; the modified glass fiber 1 is a self-made product, and the preparation method is as follows:

[0086] The glass fiber is soaked in the modified liquid 1 according to a solid-liquid ratio of 1 g:20 mL (room temperature, impregnation for 60 s and without stirring), followed by solid-liquid separation and drying of the glass fiber, to obtain the modified glass fiber 1;

[0087] The glass fiber is ECS13-03-508A produced by Jushi, and the fiber length after grinding and screening is 1-1.3 mm;

[0088] The modified liquid 1 is prepared from the following components in parts by weight:

[0089] 20 parts of fatty alcohol polyoxyethylene ether phosphate, 5 parts of lauryl phosphate, 2 parts of dodecyl benzene sulfonic acid, 5 parts of sodium secondary alkyl sulfonate, 0.3 parts of organosiloxane defoaming agent, 1 part of epoxy compound hydrolysis stabilizer, 0.5 parts of amino silane coupling agent, 3 parts of epoxy emulsion and 63.2 parts of water.

[0090] The epoxy compound hydrolysis stabilizer is TPGEE, 1,1,2,2-tetrakis (p-hydroxyphenyl) ethane tetraglycidyl ether epoxy resin produced by Shandong Jiaying Chemical Technology Co., Ltd.;

[0091] The amino silane coupling agent is KH550, γ-aminopropyl triethoxysilane produced by Hangzhou Jessica Chemical Co., Ltd.;

[0092] The epoxy emulsion is water-based epoxy emulsion JE-9064 produced by Changzhou Jinn New Material Co., Ltd.;

[0093] The modified glass fiber 2 is a self-made product, and the difference from the modified glass fiber 1 is that the modified liquid 1 during preparation is replaced by the modified liquid 2, and the modified liquid 2 is prepared from the following components in parts by weight:

[0094] 18 parts of fatty alcohol polyoxyethylene ether phosphate, 7 parts of lauryl phosphate, 3 parts of dodecyl benzene sulfonic acid, 4 parts of sodium secondary alkyl sulfonate, 0.3 parts of organosiloxane defoaming agent, 1 part of epoxy compound hydrolysis stabilizer, 0.5 parts of amino silane coupling agent, 3 parts of epoxy emulsion and 63.2 parts of water.

[0095] The modified glass fiber 3 is a self-made product, and the difference from the modified glass fiber 1 is that the modified liquid 1 during preparation is replaced by the modified liquid 3, and the modified liquid 3 is prepared from the following components in parts by weight:

[0096] 2 parts of dodecyl benzene sulfonic acid, 5 parts of sodium secondary alkyl sulfonate, 0.3 parts of organosiloxane defoaming agent, 1 part of epoxy compound hydrolysis stabilizer, 0.5 parts of amino silane coupling agent, 3 parts of epoxy emulsion and 88.2 parts of water.

[0097] The modified glass fiber 4 is a self-made product, and the only difference from the modified glass fiber 1 is that the modified liquid 1 is replaced by the modified liquid 4 during preparation, and the modified liquid 4 is prepared from the following components in parts by weight:

[0098] 20 parts of fatty alcohol polyoxyethylene ether phosphate, 5 parts of lauryl phosphate, 0.3 parts of organosiloxane defoaming agent, 1 part of epoxy compound hydrolysis stabilizer, 0.5 parts of amino silane coupling agent, 3 parts of epoxy emulsion and 63.2 parts of water.

[0099] The modified glass fiber 5 is a self-made product, and the only difference from the modified glass fiber 1 is that the modified liquid 1 is replaced by the modified liquid 5 during preparation, and the modified liquid 5 is prepared from the following components in parts by weight:

[0100] 20 parts of fatty alcohol polyoxyethylene ether phosphate, 5 parts of lauryl phosphate, 7 parts of sodium stearate, 0.3 parts of organosiloxane defoaming agent, 1 part of epoxy compound hydrolysis stabilizer, 0.5 parts of amino silane coupling agent, 3 parts of epoxy emulsion and 63.2 parts of water.

[0101] The modified glass fiber 6 is a self-made product, and the only difference from the modified glass fiber 1 is that the modified liquid 1 is replaced by the modified liquid 6 during preparation, and the modified liquid 6 is prepared from the following components in parts by weight:

[0102] 25 parts of fatty alcohol polyoxyethylene ether, 2 parts of dodecylbenzenesulfonic acid, 5 parts of sodium alkyl sulfonate, 0.3 parts of organosiloxane defoaming agent, 1 part of epoxy compound hydrolysis stabilizer, 0.5 parts of amino silane coupling agent, 3 parts of epoxy emulsion and 63.2 parts of water.

[0103] The micron-sized inorganic substance 1 is a commercially available ultra-fine talc powder HTP Ultra 5L with a purity of ≥95% and an average particle size of 2.8 μm after screening.

[0104] The micron-sized inorganic substance 2 is a commercially available talc powder TYT-777A with an average particle size of 5.3 μm.

[0105] The micron-sized inorganic substance 3 is a commercially available calcium carbonate AC-05N powder obtained after screening, with a purity of ≥95% and an average particle size of 4.5 μm.

[0106] The micron-sized inorganic substance 4 is a commercially available calcium carbonate AC-05N powder obtained after ball milling, with a purity of ≥95% and an average particle size of 3.8 μm.

[0107] The micron-sized inorganic substance 5 is a commercially available calcium carbonate AC-05N powder obtained after ball milling, with a purity of ≥95% and an average particle size of 2.6 μm.

[0108] The micrometer-sized inorganic substance 6 is a commercially available calcium carbonate AC-05N powder obtained by ball milling, with a purity of ≥95% and an average particle size of 2.1 μm.

[0109] The micrometer-sized inorganic substance 7 is a commercially available talc powder AH-1250N6, with a purity of ≥95% and an average particle size of 13 μm after sieving.

[0110] The micrometer-sized inorganic substance 8 is a commercially available calcium carbonate HX-1250, with a purity of ≥95% and an average particle size of 8 μm after sieving.

[0111] The nanometer-sized inorganic sunscreen agent 1 is a commercially available rutile titanium dioxide RCL-69, with a purity of ≥95% and an average particle size of 240 nm.

[0112] The nanometer-sized inorganic sunscreen agent 2 is a commercially available rutile titanium dioxide TIKON 33, with a purity of ≥95% and an average particle size of 290 nm after sieving.

[0113] The nanometer-sized inorganic sunscreen agent 3 is a powder obtained by ball milling the nanometer-sized inorganic sunscreen agent 2, with an average particle size of 250 nm.

[0114] The nanometer-sized inorganic sunscreen agent 4 is a powder obtained by ball milling the nanometer-sized inorganic sunscreen agent 2, with an average particle size of 180 nm.

[0115] The nanometer-sized inorganic sunscreen agent 5 is a powder obtained by ball milling the nanometer-sized inorganic sunscreen agent 2, with an average particle size of 140 nm.

[0116] The nanometer-sized filler is a commercially available zinc sulfide HD-S, with an average particle size of 300 nm.

[0117] The compatibilizer is maleic anhydride grafted polypropylene AD-105 produced by Nanhai Baimen High Polymer, with a grafting rate of 1.2%.

[0118] The processing aid is a mixture of hindered phenolic antioxidants, phosphite antioxidants and sulfur antioxidants, with a mass ratio of 1:2:1, and is produced by BASF.

[0119] The component raw materials used in the examples and comparative examples of the present application are commercially available raw materials unless otherwise specified, and the component raw materials used in each parallel experiment are the same.

[0120] The test method for the retained length of glass fiber of the products in each embodiment and comparative example is as follows: each polypropylene composition particle or product is burned at a high temperature of 650°C for 30 min to remove the resin matrix and retain the inorganic matter, the glass fiber is screened by ultrasonic treatment, the glass fiber is uniformly dispersed in water, and the retained length of the glass fiber is tested by two-dimensional test.

[0121] Table 1

[0122] Table 2

[0123] In order to verify the performance of the polypropylene composition described in the present application, the products prepared from each embodiment and comparative example are subjected to the following performance tests, and the specific steps are as follows:

[0124] (1) Alkali extraction & thermal oxidation test: each product is injection molded into a test square plate of 50*80*2mm, first, a test square plate is placed in an oven at 150°C and left to stand, and the time R1 when the surface powdering area of the square plate reaches 5% is recorded. Then, another test square plate prepared from a parallel sample is continuously soaked in a sodium hydroxide solution with pH=11 at 70°C for 40 days, and then transferred to an oven at 150°C and left to stand, and the time R2 when the surface powdering area of the square plate reaches 5% is recorded. The difference H between the time R1 and R2 of the thermal oxidation test of the sample before and after alkali extraction is calculated.

[0125] (2) Color difference test: each product is injection molded into a test square plate of 50*80*2mm, and then continuously soaked in a sodium hydroxide solution with pH=11 at 70°C for 40 days. The samples before and after soaking are tested according to the ASTM D2244-21 standard, the color difference is tested by a color difference meter, the light source is D65 / 10°, and the measurement aperture is 25.4mm.

[0126] The test results are shown in Tables 3 and 4.

[0127] Table 3

[0128] Table 4

[0129] As can be seen from Table 3 and Table 4, the polypropylene composition described in the present application has ideal appearance stability and alkali resistance to wet heat environment, and the time consumption can reach more than 1000h when the powdering area reaches 5% after the alkali extraction and thermal oxidation process, and the difference H between the thermal oxidation time consumption in the initial state can be maintained within 200h, which fully shows that it has sufficient service life in an alkali and wet heat environment, and is very suitable for application in some washing electric appliances. At the same time, the appearance change of the product after the alkali extraction is small, and the color difference can be maintained within 5, which is mainly due to the modification of the glass fiber and the control of the retention length in the product, and the specific size and function of the inorganic material also needs to be compounded, so that the desired effect can be achieved even without special process preparation or introduction of special environmental resistant agents.

[0130] In contrast, the traditional glass fiber reinforced polypropylene composition as shown in Comparative Example 1, such product due to the glass fiber is not resistant to alkaline, and polypropylene is very susceptible to degradation due to solvent and heat environment, so the powdering time is short, the color difference changes greatly after extraction, in this case, if only the introduction of inorganic materials, the degree of performance improvement is far from enough, as shown in Comparative Example 2. As can be seen from Example 1, Example 3, Comparative Examples 5-8, the modification of glass fiber has a great influence on its alkaline resistance and dispersibility, compatibility, after modification by the phosphate ester and sulfonic acid material defined in the application, the resistance of glass fiber in the product to alkaline environment is significantly improved, and the dispersibility and compatibility of the glass fiber itself are not affected, the performance of the product prepared is significantly improved compared with the product of Comparative Example 2, and if one of the two substances is missing or replaced by other substances with similar composition, the effect of the product of the example may not be achieved. The main reason is that the phosphate ester can react with the active points on the surface of the glass fiber through its functional groups to form chemical bonds or strong physical adsorption, thereby enhancing the bonding force between the glass fiber and the resin matrix, and having good alkaline resistance, which can remain stable under various alkaline conditions and is not prone to hydrolysis or decomposition reaction. On the other hand, the sulfonic acid material will be converted into salt when it is modified together with the phosphate ester in the modification liquid and the glass fiber. This salt is generally a weakly alkaline substance, which has good stability in alkaline environment, and the polar end of the salt can also form a strong chemical bond with the surface of the glass fiber. The non-polar alkane chain of the sulfonic acid material can further effectively improve the compatibility between the glass fiber and the resin matrix. The combined action of the two can ensure that the product has sufficient alkaline resistance in alkaline environment. As can be seen from Example 1, Examples 4-8, Comparative Example 3 and Comparative Examples 9-10, the main role of micron-sized inorganic material is to control the retention length of glass fiber in the product and also to improve the crystallinity of the product. The environmental performance of the product lacking this component will be greatly reduced. If micron-sized inorganic material is used in a larger size, it will not be able to regulate the glass fiber and polypropylene resin, as shown in Comparative Examples 9 and 10, neither talc nor calcium carbonate can be used in a larger size to synergize with other components. Such micron-sized inorganic material is not the smaller the better, and in general, the average particle size of 2.5-4 μm is the best.

[0131] Similarly, another inorganic material, i.e. the nano-sized opacifier as shown in Example 1, Example 9-13, Comparative Example 4 and Comparative Example 12, its mechanism of action is not exactly the same as the micro-sized inorganic material, in addition to the common regulation of the retention length of glass fiber, it also needs to have the effect of hiding white, in the absence of this component, not only the degradation rate of the product is accelerated, the service life of the product is naturally shorter, and the appearance changes significantly, and if only the introduction of ordinary nano-sized filler, as shown in Comparative Example 12, it cannot guarantee the appearance stability of the product.

[0132] At the same time, according to Example 1, Example 13-15 and Comparative Example 11, it can be seen that even if there is a nano-sized inorganic opacifier, the performance of the product may not achieve the desired effect, the addition amount of the nano-sized inorganic opacifier cannot be too much, its introduction will cause the initial heat and oxygen aging performance of the product to decrease, at the same time it will also affect the dispersibility and compatibility of the inorganic material, the regulation effect of the retention length of the glass fiber will also decrease, eventually leading to the product's alkali resistance will also decrease, as shown in Comparative Example 11, not only the difference between the initial heat and oxygen aging test value after extraction is large, but also the powdering time after extraction-heat and oxygen aging is only 768h.

[0133] According to Example 1 and Comparative Example 13, it can be seen that the retention length of the glass fiber in the polypropylene composition can be adjusted by adjusting the screw speed during preparation, in general, the higher the speed, the greater the shear force, and the smaller the retention length of the glass fiber, and even if the composition is the same, but if the regulation scale of the glass fiber does not meet the requirements of the technical solution of the present application, it also cannot achieve the ideal comprehensive performance.

[0134] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application and not to limit the scope of protection of the present application, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A polypropylene composition, characterized in that, The polypropylene composition comprises the following components by weight: polypropylene resin 59-71 parts, modified glass fiber 20-40 parts, compatibilizer 1-5 parts, micron-sized inorganic substance 2-5 parts, nano-sized inorganic sunscreen 0.5-3 parts; the modified glass fiber is a glass fiber modified by a modifying liquid comprising phosphate and sulfonic acid substances, and has a retention length of 300-360 μm; the micron-sized inorganic substance has an average particle size of ≤6 μm; the nano-sized inorganic sunscreen comprises nano-sized titanium dioxide.

2. The polypropylene composition according to claim 1, wherein the micron-sized inorganic substance comprises at least one of micron-sized calcium carbonate and micron-sized silicate minerals; preferably, the silicate minerals comprise at least one of talcum powder, montmorillonite, kaolin, sepiolite and mica.

3. The polypropylene composition according to claim 2, characterized in that, the micron-sized inorganic substance has an average particle size of 2-6 μm; preferably, the micron-sized inorganic substance has an average particle size of 2.5-4 μm.

4. The polypropylene composition according to claim 1, wherein the polypropylene composition has a melt flow rate of 0.5 to 5 g / 10 min. at 230°C under a load of 2.16 kg. the nano-sized inorganic sunscreen has an average particle size of 100-300 nm.

5. The polypropylene composition according to claim 1, wherein the polypropylene composition has a melt flow rate of 0.5 to 5 g / 10 min. the phosphate substance is a fatty alcohol phosphate ester; the sulfonic acid substance is a mixture of dodecyl benzene sulfonic acid and sodium secondary alkyl sulfonate.

6. The polypropylene composition according to claim 1, wherein the polypropylene composition has a melt flow rate of 0.5 to 5 g / 10 min. the polypropylene resin has a melt flow rate of 20-150 g / 10 min at 230℃ under a load of 2.16 kg according to ISO 1133-2011.

7. The polypropylene composition according to claim 1, wherein the polypropylene composition has a melt flow rate of 0.5 to 5 g / 10 min. the polypropylene composition further comprises 0-1 parts by weight of a processing aid; preferably, the processing aid comprises at least one of an antioxidant and a lubricant.

8. Process for the preparation of the polypropylene composition according to any one of claims 1 to 7, characterized in that, The polypropylene composition comprises the following steps: adding the components into a screw extruder for melt extrusion granulation to obtain the polypropylene composition.

9. Use of the polypropylene composition according to any one of claims 1-7 in the preparation of a washing appliance.

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