Oil-resistant and crack-resistant PC materials and their preparation methods

Abstract

The application relates to the technical field of high polymer materials, in particular to an oil-resistant and anti-cracking PC material and a preparation method thereof; the preparation raw materials of the oil-resistant and anti-cracking PC material include polycarbonate and an oil-resistant compound additive; wherein the oil-resistant compound additive includes an oil-resistant additive and photocatalyst nano titanium dioxide with a core-shell structure; the preparation method of the oil-resistant and anti-cracking PC material includes mixing and co-extruding the preparation raw materials; and the oil-resistant and anti-cracking PC material can realize long-acting oil-resistant and anti-cracking performance.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to grease-resistant and crack-resistant PC materials and their preparation methods. Background Technology

[0002] Polycarbonate (PC) is a general-purpose engineering plastic with excellent comprehensive properties, including superior heat resistance, impact resistance, flame retardancy, dimensional stability, and electrical insulation. However, PC materials are prone to cracking when used under stress or in specific grease environments (arc quenching oil, red oil, white oil).

[0003] The related technologies provide a method to improve the grease and crack resistance of PC by adding grease-resistant components such as polyolefins, organosilicon additives, and rubber elastomers to PC. This method can improve the grease and crack resistance of PC to a certain extent in a short period of time, but a certain proportion of crack resistance failure will still occur in a continuous stress grease environment, that is, it is difficult to make PC materials achieve long-term grease and crack resistance. Summary of the Invention

[0004] The purpose of this invention is to provide a grease-resistant and crack-resistant PC material and its preparation method, which can achieve long-term grease-resistant and crack-resistant properties.

[0005] This invention is implemented as follows:

[0006] In a first aspect, the present invention provides an oil-resistant and crack-resistant PC material, the raw materials for preparing the oil-resistant and crack-resistant PC material including: polycarbonate and oil-resistant compounding agent; wherein, the oil-resistant compounding agent includes oil-resistant additive and photocatalytic nano-titanium dioxide with a core-shell structure.

[0007] In an optional embodiment, the core-shell structured photocatalytic nano-titanium dioxide includes photocatalytic nano-titanium dioxide and a silica shell covering the photocatalytic nano-titanium dioxide; the silica shell has micropores.

[0008] In an optional implementation, the pore size of the micropores is 0.1 μm-50 μm.

[0009] In an optional embodiment, the weight percentage of the core-shell structured photocatalytic nano-titanium dioxide in the grease-resistant compounding agent is less than or equal to 35%.

[0010] In optional embodiments, the raw materials for preparing the grease-resistant and crack-resistant PC material further include at least one of a toughening agent, a flame retardant, and auxiliary additives; and / or,

[0011] The auxiliary agents include at least one of colorants, antioxidants, and lubricants.

[0012] In an optional embodiment, the raw materials for preparing the grease-resistant and crack-resistant PC material include, by weight: 50-90 parts of polycarbonate, 0.5-30 parts of grease-resistant compounding agent, 0-15 parts of toughening agent, 0.1-2 parts of flame retardant and 0.5-3 parts of auxiliary additives.

[0013] In optional embodiments, the polycarbonate has a melt flow rate of 6-18 g / 10 min and a number-average molecular weight of 28,000-35,000; and / or,

[0014] Oil-resistant additives include at least one of silicone masterbatch, organosilicon additives, rubber elastomers, and polyolefins; and / or,

[0015] Toughening agents include at least one of maleic anhydride-grafted ethylene propylene diene monomer (EPDM), maleic anhydride-grafted ethylene-1-octene copolymer, methyl methacrylate-butadiene-styrene terpolymer, and organosilicon toughening agents; and / or,

[0016] Flame retardants include at least one of organosilicon flame retardants, potassium perfluorobutyl sulfonate, and potassium benzenesulfonate.

[0017] In optional embodiments, the silicone toughening agent includes at least one of S201, SX006, MX-520S, and MX-550H; and / or,

[0018] Organosilicon flame retardants include at least one of organosilicon silsesquioxane and polymethylsilsesquioxane.

[0019] Secondly, the present invention provides a method for preparing an oil-resistant and crack-resistant PC material as described in any of the foregoing embodiments, comprising: mixing and co-extruding the raw materials.

[0020] In an optional embodiment, the co-extrusion step includes: extruding the mixed raw materials using a screw extruder, wherein the temperature of the screw extruder is controlled as follows: 200-230°C in the feed zone, 240-250°C in zone 1, 250-260°C in zone 2, 260-270°C in zone 3, 270-275°C in zone 4, 275-280°C in zone 5, 280-285°C in zone 6, 285-290°C in zone 7, 290-295°C in zone 8, and 295-305°C at the die head; and / or,

[0021] The screw extruder has a rotational speed of 300-400 r / min, a screw length-to-diameter ratio of >55, and a screw diameter of 40-45 mm.

[0022] The present invention has the following beneficial effects:

[0023] The grease-resistant and crack-resistant PC material provided in this invention incorporates a compounded grease-resistant additive into polycarbonate (PC) material. This grease-resistant additive includes a grease-resistant agent and a core-shell structured photocatalytic nano-titanium dioxide. This enhances both the short-term and long-term grease-resistant crack resistance of PC. The grease-resistant agent reduces the chance of direct contact between the PC material and grease, prolonging the time grease impregnates the PC and delaying grease cracking, thus ensuring short-term grease-resistant crack resistance. The core-shell structured photocatalytic nano-titanium dioxide can both adsorb and decompose grease, mitigating the slow erosion of the PC substrate caused by long-term grease accumulation, thereby achieving long-term grease-resistant crack resistance.

[0024] Moreover, the grease-resistant compounding agent of the present invention is compounded with grease-resistant additives and photocatalytic nano-titanium dioxide with a core-shell structure. Compared with the use of grease-resistant additives alone, it can reduce the amount of grease-resistant additives used, thereby alleviating the problem of reduced heat resistance and flame retardancy of PC materials caused by the use of grease-resistant additives.

[0025] The preparation method provided in this embodiment of the invention has the aforementioned beneficial effects, which will not be repeated here. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0027] This invention provides an oil-resistant and crack-resistant PC material, the raw materials of which include: polycarbonate and oil-resistant compounding agents; wherein, the oil-resistant compounding agents include oil-resistant additives and photocatalytic nano-titanium dioxide with a core-shell structure.

[0028] The grease-resistant and crack-resistant PC material of this invention can improve the short-term and long-term grease-resistant and crack-resistant properties of PC. Among them, the grease-resistant additive can reduce the chance of direct contact between PC material and grease, prolong the time of grease wetting PC, and play a role in delaying the grease cracking time of PC, that is, ensuring the grease-resistant and crack-resistant properties in the short term. Meanwhile, the photocatalytic nano-titanium dioxide with core-shell structure can adsorb grease on the one hand and decompose grease on the other hand, improve the slow erosion of the PC matrix caused by long-term grease accumulation, and thus achieve a long-term grease-resistant and crack-resistant effect.

[0029] Moreover, the grease-resistant compounding agent of the present invention is compounded with grease-resistant additives and photocatalytic nano-titanium dioxide with a core-shell structure. Compared with the use of grease-resistant additives alone, it can reduce the amount of grease-resistant additives used, thereby alleviating the problem of reduced heat resistance and flame retardancy of PC materials caused by the use of grease-resistant additives.

[0030] Optionally, the melt flow rate of the polycarbonate (PC resin) is 6-18 g / 10 min, for example: 6 g / 10 min, 8 g / 10 min, 10 g / 10 min, 12 g / 10 min, 14 g / 10 min, 16 g / 10 min, 18 g / 10 min, etc.; and the number average molecular weight is 28,000-35,000, for example: 28,000, 30,000, 32,000, 35,000, etc. High molecular weight PC materials themselves have good mechanical strength, heat resistance, electrical insulation properties, and resistance to stress cracking.

[0031] Optionally, the grease-resistant additives include one or more of silicone masterbatches, organosilicon additives, rubber elastomers, and polyolefins, mixed in any proportion. Among these, organosilicon additives may refer to silicone rubber, rubber elastomers may refer to one or more of thermoplastic polyester elastomers (TPEE) and thermoplastic polyurethanes (TPU), and polyolefins may refer to poly4-methyl-1-pentene, etc., without specific limitations.

[0032] Optionally, the core-shell structured photocatalytic nano-titanium dioxide comprises photocatalytic nano-titanium dioxide and a silica shell coating the photocatalytic nano-titanium dioxide, i.e., the core-shell structured photocatalytic nano-titanium dioxide is a photocatalytic nano-titanium dioxide / SiO2 core-shell; wherein, the silica shell has micropores. The microporous structure of the silica shell can reliably adsorb grease, thereby enhancing the decomposition effect of the photocatalytic nano-titanium dioxide on grease while adsorbing grease, thus effectively improving the slow erosion of the PC matrix material caused by grease accumulation, and effectively achieving long-term oil resistance and crack resistance. Moreover, using a core-shell structured photocatalytic nano-titanium dioxide can also avoid the problem of PC, as an organic matter, being decomposed by the photocatalytic nano-titanium dioxide (i.e., avoiding the degradation of PC molecular chains), which would lead to a decrease in the strength of the PC material.

[0033] Furthermore, the pore size of the micropores ranges from 0.1μm to 50μm, for example: 0.1μm, 1μm, 5μm, 10μm, 15μm, 20μm, 30μm, 35μm, 40μm, 50μm, etc. Micropores with a pore size of 0.1μm-50μm can reliably block the entry of PC molecular chains while adsorbing grease, ensuring that the PC matrix is ​​protected from grease erosion for a long time and reliably achieving long-lasting oil resistance and crack resistance.

[0034] Furthermore, the weight percentage of core-shell structured photocatalytic nano-titanium dioxide in the grease-resistant compounding agent is less than or equal to 35%, and in a preferred embodiment, the weight percentage of core-shell structured photocatalytic nano-titanium dioxide is greater than 0%. Optimizing the core-shell structured photocatalytic nano-titanium dioxide in the grease-resistant compounding agent can, on the one hand, enable the modified PC material to simultaneously possess both short-term and long-term oil resistance and crack resistance properties; on the other hand, by controlling the proportion of core-shell structured photocatalytic nano-titanium dioxide, the amount of grease-resistant additives compounded with it can be optimized, thereby ensuring the heat resistance and flame retardancy of the modified PC material.

[0035] To further ensure the strength, flame retardancy, etc. of the modified grease-resistant and crack-resistant PC material, the raw materials for preparing the grease-resistant and crack-resistant PC material also include at least one of toughening agents, flame retardants, and auxiliary additives, wherein the auxiliary additives include at least one of color powder, antioxidants, and lubricants.

[0036] Optionally, the raw materials for preparing the grease-resistant and crack-resistant PC material include, by weight: 50-90 parts of polycarbonate (e.g., 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, etc.), 0.5-30 parts of grease-resistant compounding agents (e.g., 0.5 parts, 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, etc.), 0-15 parts of toughening agents (e.g., 0 parts, 1 part, 3 parts, 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, etc.), 0.1-2 parts of flame retardant (e.g., 0.1 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, etc.), and 0.5-3 parts of auxiliary additives (e.g., 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, etc.). Optimizing the dosage of oil-resistant compounding agents, toughening agents, flame retardants, and auxiliary additives can ensure that the modified PC material has good oil resistance and crack resistance while still maintaining good strength, heat resistance, and flame retardancy.

[0037] Optionally, the toughening agent includes one or more of the following, mixed in any proportion: maleic anhydride-grafted ethylene propylene diene monomer (EPDM-g-MAH), maleic anhydride-grafted ethylene-1-octene copolymer (POE-g-MAH), methyl methacrylate-butadiene-styrene terpolymer (MBS), and organosilicon toughening agents.

[0038] Furthermore, the organosilicon toughening agent (i.e., silicon-based toughening agent) includes one or more of the following: silicone-propylene rubber toughening agent S201, silicone-propylene rubber toughening agent SX006, silicon-based toughening agent MX-520S, and silicon-based toughening agent MX-550H, mixed in any proportion. Besides improving the strength of modified PC materials, organosilicon toughening agents can also improve the compatibility of grease-resistant compounding agents, that is, improve the compatibility of the grease-resistant compounding system. Specifically, they can improve the compatibility between the grease-resistant additives (organic phase) and the core-shell structured photocatalytic nano-titanium dioxide (inorganic phase). Furthermore, they enable the inorganic core-shell structured photocatalytic nano-titanium dioxide to have good compatibility with other organic phases throughout the formulation, thereby ensuring that the modified PC material possesses good toughness while also exhibiting good short-term and long-term oil resistance and crack resistance.

[0039] Optionally, the flame retardant includes one or more of organosilicon flame retardants, potassium perfluorobutyl sulfonate, and potassium benzenesulfonate, mixed in any proportion. In embodiments where both flame retardants and toughening agents are added simultaneously, not only can the modified PC material possess good flame retardancy, but the synergistic impregnation of an oil-resistant compound additive containing a photocatalytic nano-titanium dioxide / SiO2 core-shell structure by the flame retardant and toughening agent can further enhance the toughness of the material.

[0040] Furthermore, organosilicon flame retardants (i.e., silicon-based flame retardants) include one or more of organosilicon silsesquioxanes and polymethylsilsesquioxanes, mixed in any proportion. Besides improving the flame retardancy of modified PC materials, organosilicon flame retardants can also improve the compatibility of grease-resistant compounding agents, that is, improve the compatibility of grease-resistant compounding systems. Furthermore, they enable the inorganic core-shell structured photocatalytic nano-titanium dioxide to have good compatibility with other organic phases throughout the formulation, thereby ensuring that the modified PC material possesses good flame retardancy while also exhibiting good short-term and long-term oil resistance and crack resistance.

[0041] It should be noted that the simultaneous use of silicon-based toughening agents and silicon-based flame retardants can reliably improve the compatibility of grease-resistant compounding agents, that is, improve the compatibility of the grease-resistant compounding system, and enable the inorganic core-shell structured photocatalytic nano-titanium dioxide to have good compatibility with other organic phases throughout the formulation. Furthermore, silicon-based flame retardants and silicon-based toughening agents have good wettability with the core-shell structured photocatalytic nano-titanium dioxide, thereby reducing the amount of toughening agent added and avoiding the problem of decreased flame retardancy and heat resistance caused by excessive toughening agent addition. It should be understood that the simultaneous use of silicon-based toughening agents and silicon-based flame retardants, at a certain dosage, can further improve the flame retardancy and strength of modified PC materials, and improve the short-term and long-term crack resistance of modified PC.

[0042] It should be noted that when auxiliary additives include lubricants, the addition of lubricants can reduce friction between molecules within the plastic, improve the processing performance of the plastic, and increase production efficiency. When auxiliary additives include antioxidants, antioxidants can enhance the oxidation resistance of the material during processing and use, and improve the performance degradation caused by localized degradation due to thermal aging under high-temperature injection molding and high-temperature exposure conditions.

[0043] The present invention also provides a method for preparing an oil-resistant and crack-resistant PC material, comprising mixing and co-extruding various raw materials.

[0044] Specifically, the co-extrusion steps include: extruded the mixed raw materials using a screw extruder, and controlling the temperature of the screw extruder's feed zone to 200-230℃ (e.g., 200℃, 210℃, 220℃, 230℃, etc.), the temperature of zone one to 240-250℃ (e.g., 240℃, 245℃, 250℃, etc.), the temperature of zone two to 250-260℃ (e.g., 250℃, 255℃, 260℃, etc.), the temperature of zone three to 260-270℃ (e.g., 260℃, 265℃, 270℃, etc.), and the temperature of zone four to 270-275℃. The temperature control ranges from 270℃, 272℃, 275℃, etc. for each zone: Zone 5: 275-280℃ (e.g., 275℃, 277℃, 280℃, etc.); Zone 6: 280-285℃ (e.g., 280℃, 282℃, 285℃, etc.); Zone 7: 285-290℃ (e.g., 285℃, 288℃, 290℃, etc.); Zone 8: 290-295℃ (e.g., 290℃, 292℃, 295℃, etc.); and the machine head temperature is controlled at 295-305℃ (e.g., 295℃, 300℃, 305℃, etc.).

[0045] The screw extruder has a rotational speed of 300-400 r / min (e.g., 300 r / min, 330 r / min, 350 r / min, 380 r / min, 400 r / min, etc.), a screw length-to-diameter ratio >55 (e.g., 55.1, 56, 58, 60, etc.), and a screw diameter of 40-45 mm (e.g., 40 mm, 42 mm, 45 mm, etc.).

[0046] Furthermore, a screw extruder can refer to a twin-screw extruder, without being specifically limited here.

[0047] The present invention will be further described in detail below with reference to the embodiments.

[0048] Example 1

[0049] A grease-resistant and crack-resistant PC material comprises the following components in parts by weight: 68 parts PC resin, 20 parts grease-resistant additive TPEE, 5 parts photocatalyst nano-titanium dioxide / SiO2 core-shell (the micropores of the silica shell have a pore size of 0.1 μm), 4 parts toughening agent S201, 0.3 parts flame retardant organosilicon silsesquioxane (POSS) FR-Si980, and 2.7 parts other additives.

[0050] The above raw materials are mixed and added to the hopper of a twin-screw extruder, where they are melt-granulated. The process parameters of the twin-screw extruder are as follows: feed zone temperature 230℃, zone 1 temperature 250℃, zone 2 temperature 260℃, zone 3 temperature 270℃, zone 4 temperature 275℃, zone 5 temperature 280℃, zone 6 temperature 285℃, zone 7 temperature 290℃, zone 8 temperature 295℃, die head temperature 305℃, twin-screw extruder speed 300 r / min, screw length-to-diameter ratio 56, and screw diameter 45 mm.

[0051] Example 2

[0052] A grease-resistant and crack-resistant PC material comprises the following components in parts by weight: 68 parts PC resin, 20 parts grease-resistant additive TPEE, 5 parts photocatalyst nano-titanium dioxide / SiO2 core-shell (the micropores of the silica shell have a pore size of 50μm), 4 parts toughening agent S201, 0.5 parts flame retardant organosilicon silsesquioxane (POSS) FR-Si980, and 2.5 parts other additives.

[0053] The above raw materials are mixed and added to the hopper of a twin-screw extruder, where they are melt-granulated. The process parameters of the twin-screw extruder are as follows: feed zone temperature 200℃, zone 1 temperature 240℃, zone 2 temperature 250℃, zone 3 temperature 260℃, zone 4 temperature 270℃, zone 5 temperature 275℃, zone 6 temperature 280℃, zone 7 temperature 285℃, zone 8 temperature 290℃, die head temperature 295℃, twin-screw extruder speed 400 r / min, screw length-to-diameter ratio 56, screw diameter 40 mm.

[0054] Example 3

[0055] A grease-resistant and crack-resistant PC material comprises the following components in parts by weight: 78 parts PC resin, 10 parts grease-resistant additive TPEE, 5 parts photocatalyst nano-titanium dioxide / SiO2 core-shell (the micropores of the silica shell have a pore size of 20μm), 4 parts toughening agent S201, 0.3 parts flame retardant organosilicon silsesquioxane (POSS) FR-Si980, and 2.7 parts other additives.

[0056] The above raw materials are mixed and added to the hopper of a twin-screw extruder, where they are melt-granulated. The process parameters of the twin-screw extruder are as follows: feed zone temperature 215℃, zone 1 temperature 245℃, zone 2 temperature 255℃, zone 3 temperature 265℃, zone 4 temperature 272℃, zone 5 temperature 277℃, zone 6 temperature 282℃, zone 7 temperature 288℃, zone 8 temperature 292℃, die head temperature 300℃, twin-screw extruder speed 350 r / min, screw length-to-diameter ratio 57, and screw diameter 43 mm.

[0057] Example 4

[0058] A grease-resistant and crack-resistant PC material comprises the following components in parts by weight: 68 parts PC resin, 20 parts grease-resistant additive polyolefin poly4-methyl-1-pentene, 5 parts photocatalyst nano-titanium dioxide / SiO2 core-shell (the micropores of the silica shell have a pore size of 10 μm), 4 parts toughening agent S201, 0.5 parts flame retardant organosilicon silsesquioxane (POSS) FR-Si980, and 2.5 parts other additives.

[0059] The preparation process is the same as in Example 1.

[0060] Example 5

[0061] A grease-resistant and crack-resistant PC material comprises the following components in parts by weight: 68 parts PC resin, 20 parts grease-resistant additive TPEE, 5 parts photocatalyst nano-titanium dioxide / SiO2 core-shell (the micropores of the silica shell have a pore size of 15μm), 4 parts toughening agent S201, 0.5 parts flame retardant potassium benzenesulfonate (KSS), and 2.5 parts other additives.

[0062] The preparation process is the same as in Example 1.

[0063] Example 6

[0064] A grease-resistant and crack-resistant PC material comprises the following components in parts by weight: 72 parts PC resin, 20 parts grease-resistant additive TPEE, 5 parts photocatalyst nano-titanium dioxide / SiO2 core-shell (the micropores of the silica shell have a pore size of 40μm), 0.5 parts flame retardant organosilicon silsesquioxane (POSS) FR-Si980, and 2.5 parts other additives.

[0065] The preparation process is the same as in Example 1.

[0066] Comparative Example 1

[0067] A grease-resistant and crack-resistant PC material comprises the following components in parts by weight: 68 parts PC resin, 25 parts grease-resistant additive TPEE, 4 parts toughening agent S201, 0.5 parts flame retardant potassium benzenesulfonate (KSS), and 2.5 parts other additives.

[0068] The preparation process is the same as in Example 1.

[0069] Comparative Example 2

[0070] A grease-resistant and crack-resistant PC material comprises the following components in parts by weight: 97 parts PC resin, 0.5 parts flame retardant organosilicon silsesquioxane (POSS) FR-Si980, and 2.5 parts other additives.

[0071] The preparation process is the same as in Example 1.

[0072] Comparative Example 3

[0073] A grease-resistant and crack-resistant PC material comprises the following components in parts by weight: 88 parts PC resin, 5 parts photocatalyst nano-titanium dioxide / SiO2 core-shell (the micropores of the silica shell have a pore size of 25μm), 4 parts toughening agent S201, 0.3 parts flame retardant organosilicon silsesquioxane (POSS) FR-Si980, and 2.7 parts other additives.

[0074] The preparation process is the same as in Example 1.

[0075] Comparative Example 4

[0076] A grease-resistant and crack-resistant PC material comprises the following components in parts by weight: 97 parts PC resin, 0.5 parts flame retardant potassium benzenesulfonate (KSS), and 2.5 parts other additives.

[0077] The preparation process is the same as in Example 1.

[0078] Comparative Example 5

[0079] The only difference from Example 2 is that the photocatalytic nano-titanium dioxide / SiO2 core-shell is replaced with ordinary anatase titanium dioxide.

[0080] Comparative Example 6

[0081] The only difference from Example 2 is that the photocatalytic nano-titanium dioxide / SiO2 core-shell is replaced with a nano-level anatase titanium dioxide core-shell-free structure.

[0082] The plastic granules prepared in each embodiment and each comparative example were injection molded into standard specimens for physical property testing in the ungreased state, impact strength testing in the greased state, and grease cracking resistance evaluation. The test and evaluation results are shown in Table 1.

[0083] The specific test methods for the relevant performance indicators are as follows:

[0084] 1) Notched impact strength of machine-milled cantilever beams: tested according to GB / T1843;

[0085] 2) Vertical burning performance: tested according to UL94;

[0086] 3) Glow wire flammability index (GWFI): Tested according to GB / T16915;

[0087] 4) Ball pressure test: GB / T 5169.21;

[0088] At the same time, each set of samples underwent grease resistance testing and crack evaluation, using the following methods:

[0089] The two ends of an ISO standard tensile specimen are clamped onto a fixture with a span of 154.6 mm ± 0.4 mm. A single-sided coating of arc-extinguishing oil is uniformly applied to a rectangular area on the specimen surface, with the oil mass controlled between 0.10 g and 0.15 g. Simultaneously, notched impact specimens with the same formulation and coated with arc-extinguishing oil (with the oil mass controlled between 0.25 g and 0.30 g) are prepared (the impact specimens are uniformly coated on all four sides and at the notch). The fixture and the oiled impact specimens are then divided into A and B. Two groups: Group A was placed in a 23℃ darkroom in a constant temperature sealed bag environment for 24h / 168h / 720h respectively. The surface of the sample was visually observed for cracks or fissures, and the impact strength of the oiled sample with the same formula that did not crack was tested. Group B samples were placed in a 23℃ room with 500 lumens light and light-treated for 30min / 24h / 168h respectively. The surface of the sample was visually observed for cracks or fissures, and the impact strength of the oiled sample with the same formula that did not crack was tested.

[0090] Note 1: Five samples were tested for each condition and the average value was taken.

[0091] Note 2: The temperature at the front end of the injection molding machine is controlled at 280℃~310℃ when preparing the sample; the arc extinguishing oil manufacturer is Yiligao, and the brand is SGB.

[0092] Table 1 Test Results

[0093]

[0094]

[0095] The experimental results are shown in Table 1. Analysis of the uncoated performance test data shows that the heat resistance of the material decreases when TPEE or conventional grease-resistant additives such as poly-4-methyl-1-pentene are added. In other words, the higher the ball pressure test result in the table, the more TPEE is added, the more obvious the effect on heat resistance. Moreover, the larger the amount of conventional grease-resistant additives added, the negative impact on the flame retardant properties of the material. Furthermore, comparison of Examples 2 and 4 shows that the effect of TPEE on heat resistance is less than that of polyolefins.

[0096] Analysis of the oil coating performance test data and crack evaluation shows that: the differences in data from Comparative Examples 1, 2, and 4 indicate that the main role of TPEE and polyolefin is to improve the short-term oil resistance of PC materials. The tensile specimen without these additives cracked after 24 hours under stress, while the one with these additives could extend the time to one month before failure. Example 6 shows that in the absence of toughening agents, the modified material itself has poor toughness. Even with conventional TPEE oil-resistant additives, cracking still occurred within a week when the photocatalyst nano-titanium dioxide / SiO2 core-shell did not function. The comparison between Example 2 and Comparative Example 1 shows that the addition of the core-shell structure photocatalyst significantly improved the long-term crack resistance of the material. The solution with the core-shell photocatalyst did not crack after one month, and the impact strength retention rate of the specimens was very high. The photocatalyst test data shows that under 500 lumens of light, the material performance degradation reached a basic equilibrium point after 24 hours of treatment, and the impact strength no longer decreased significantly with increasing time. The comparison data table between Comparative Example 5 and Example 2 is also relevant. The photocatalyst nano-titanium dioxide / SiO2 core-shell structure exhibits better toughening effect on the matrix than ordinary titanium dioxide. Even without light, the photocatalyst nano-titanium dioxide / SiO2 core-shell structure still possesses a certain degree of grease resistance. Ordinary titanium dioxide, under light, shows no significant grease-decomposing effect; therefore, the impact strength of the material continuously decreases over time, and cracking occurs within a month. Comparative data from Comparative Example 6 and Example 2 show that the core-shell structure-less nano-titanium dioxide not only decomposes grease but also damages the PC substrate. Specifically, the results of Comparative Example 6 indicate that without the protection of the shell, the PC substrate is continuously decomposed by the photocatalyst, leading to a continuous decrease in strength until material failure. Therefore, the photocatalyst nano-titanium dioxide with a core-shell structure containing micropores ensures that small molecule grease can enter and be adsorbed into the micropores of the silica shell, guaranteeing efficient adsorption and decomposition of grease. Simultaneously, the pore size of 0.1μm to 50μm effectively blocks the entry of PC molecular chains, protecting the matrix from grease erosion.

[0097] Comparing the data from Examples 2 and 5, it can be seen that when the amounts of toughening agent and flame retardant are the same, using silicon-based toughening agent and flame retardant can further improve flame retardancy and strength, and enhance the short-term and long-term crack resistance of modified PC.

[0098] Based on the test results and the above analysis, it can be seen that the optimal solution for modifying the grease-resistant and crack-resistant PC material, as shown in Example 2, is the one containing a photocatalytic nano-titanium dioxide / SiO2 core-shell grease-resistant additive compound, as well as silicon-based toughening agents and silicon-based flame retardants.

[0099] In summary, the grease-resistant and crack-resistant PC material of the present invention can achieve long-term grease-resistant and crack-resistant performance.

[0100] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A grease resistant, crack resistant PC material, characterized by, The preparation raw material of the grease-resistant anti-cracking PC material comprises: polycarbonate and grease-resistant compound additives; wherein the grease-resistant compound additives comprise grease-resistant additives and photocatalyst nano-titanium dioxide with a core-shell structure; The photocatalyst nano-titanium dioxide with a core-shell structure comprises photocatalyst nano-titanium dioxide and a silica shell layer coated outside the photocatalyst nano-titanium dioxide; the silica shell layer has micropores; The grease-resistant additives comprise at least one of rubber-based elastomers and polyolefins, and the rubber-based elastomers are one or more of thermoplastic polyester elastomers and thermoplastic polyurethane; The weight percentage of the photocatalyst nano-titanium dioxide with a core-shell structure in the grease-resistant compound additives is less than or equal to 35%.

2. The grease resistant, crack resistant PC material of claim 1, wherein, The pore size of the micropores is 0.1-50 μm.

3. The grease resistant, crack resistant PC material of claim 1, wherein, The preparation raw material of the grease-resistant anti-cracking PC material further comprises at least one of toughening agents, flame retardants and auxiliary additives; The auxiliary additives comprise at least one of toner, antioxidants and lubricants.

4. The grease resistant, crack resistant PC material of claim 3, wherein, The preparation raw material of the grease-resistant anti-cracking PC material comprises, by weight: 50-90 parts of the polycarbonate, 0.5-30 parts of the grease-resistant compound additives, 0-15 parts of the toughening agents, 0.1-2 parts of the flame retardants and 0.5-3 parts of auxiliary additives.

5. The grease resistant, crack resistant PC material of claim 4, wherein, The polycarbonate has a melt mass flow rate of 6-18 g / 10 min and a number average molecular weight of 28-35 thousand; and / or, The toughening agents comprise at least one of maleic anhydride grafted ethylene-propylene-diene rubber, maleic anhydride grafted ethylene-1-octene copolymer, methyl methacrylate-butadiene-styrene terpolymer and silicone toughening agent; and / or, The flame retardants comprise at least one of silicone flame retardant, potassium perfluorobutylsulfonate and potassium benzenesulfonyl sulfonate.

6. The grease resistant, crack resistant PC material of claim 5, wherein, The silicone toughening agent comprises at least one of S201, SX006, MX-520S and MX-550H; and / or, The silicone flame retardant comprises at least one of organosilicon silsesquioxane and polymethylsilsesquioxane.

7. The method of making a grease resistant, crack resistant PC material according to any one of claims 1-6, wherein, Comprise: Mixing the preparation raw material, co-extrusion.

8. The method of making a grease resistant, crack resistant PC material of claim 7, wherein, The step of co-extrusion comprises: extruding the mixed preparation raw material by using a screw extruder, and controlling the temperature of the feeding zone of the screw extruder to be 200-230 ℃, the temperature of the first zone to be 240-250 ℃, the temperature of the second zone to be 250-260 ℃, the temperature of the third zone to be 260-270 ℃, the temperature of the fourth zone to be 270-275 ℃, the temperature of the fifth zone to be 275-280 ℃, the temperature of the sixth zone to be 280-285 ℃, the temperature of the seventh zone to be 285-290 ℃, the temperature of the eighth zone to be 290-295 ℃, and the temperature of the die head to be 295-305 ℃; and / or, The rotation speed of the screw extruder is 300-400 r / min, the length-diameter ratio of the screw is greater than 55, and the diameter of the screw is 40-45 mm.

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