Preparation method of lubricating grease for preventing cracking of PC and ABS mixed material

Abstract

The invention discloses a preparation method of lubricating grease for preventing cracking of a mixture of PC and ABS, and particularly relates to the technical field of lubricating grease, the method comprises the following steps: selecting poly-alpha-olefin (PAO) and deeply refined paraffin-based mineral oil as base oil according to a specific proportion, and performing dehydration treatment; adding additives such as an antioxidant, an anti-wear reagent at extreme pressure, a thickening agent, an anticorrosive agent and a compatilizer, and stirring and mixing; reacting under the protection of specific temperature, pressure and nitrogen; carrying out reduced pressure distillation and multi-layer filtration refining on the reaction product; and finally, multi-project quality detection is carried out. The prepared lubricating grease can effectively prevent the PC and ABS mixture from cracking, has good comprehensive performance, and is suitable for lubrication of plastic products prepared from the PC and ABS mixture.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating greases, and more specifically, to a preparation method of a lubricating grease for preventing cracking of PC and ABS mixed materials. Background Art

[0002] In the modern plastic processing and manufacturing field, the mixture of PC (polycarbonate) and ABS (acrylonitrile-butadiene-styrene copolymer) is widely used in the production of many products such as electronic and electrical appliance casings, automotive interior parts, and mechanical components due to its combination of the high strength and high heat resistance of PC and the good processing performance, impact toughness, and surface gloss of ABS. For example, in the field of electronic devices, the casings of mobile phones and computers often use the mixture of PC and ABS to meet the requirements for appearance texture and structural strength; in the automotive industry, components such as instrument panels and door interior panels use this mixture to achieve both aesthetics and durability.

[0003] In the actual production process, in order to improve the processing performance of plastic products, reduce the friction coefficient, and extend the service life, lubricating greases are often added. However, the characteristic differences between PC and ABS materials pose difficulties for lubrication. The glass transition temperature of PC is relatively high, and it can be fully melted and plasticized only at a high temperature of about 260°C; while the processing temperature of ABS is relatively low, generally about 200°C. This large difference in sol temperature makes ABS prone to carbonization and decomposition in the high-temperature environment required by PC during the mixing process, thereby affecting the material properties.

[0004] During the use of lubricating greases, they will gradually penetrate into the microscopic interface between PC and ABS. Due to the chemical structure characteristics of ABS, it has a strong affinity with lubricating greases and is prone to mutual fusion. When plastic products are subjected to thread tightening force, assembly pressure, or external force impact during use, the interfacial bonding force between PC and ABS, which was originally weakened by the penetration of lubricating greases, is further reduced, resulting in stress concentration inside the material and ultimately causing cracking of the PC and ABS mixed materials. This not only causes defects in the appearance of the product but also reduces key indicators such as the mechanical properties and waterproof properties of the product, seriously affecting the product quality, increasing the defective rate, and raising the production cost.

[0005] Currently, most of the existing lubricating greases on the market are general-purpose products and lack designs targeted at the characteristics of PC and ABS mixed materials. Traditional lubricating greases have poor effects in solving the problem of cracking of PC and ABS mixed materials and cannot meet the growing demand for the production of high-quality plastic products.

[0006] Therefore, a preparation method of a lubricating grease for preventing cracking of PC and ABS mixed materials is proposed. Summary of the Invention

[0007] To overcome the above defects of the prior art, the present invention provides a method for preparing a lubricating grease to prevent cracking of PC and ABS blends, so as to solve the problems raised in the above background art.

[0008] To achieve the above object, the present invention provides the following technical solution: A method for preparing a lubricating grease to prevent cracking of PC and ABS blends, comprising the following steps:

[0009] S1: Select a suitable base oil, the base oil includes synthetic oil and mineral oil, wherein the synthetic oil is polyalphaolefin (PAO), and its mass ratio in the base oil is 30%-50%, and the mineral oil is a paraffin-based mineral oil that has been deeply refined, and its mass ratio in the base oil is 50%-70%. Dehydrate the selected base oil. Under the conditions of a vacuum degree of 0.05-0.08 MPa and a temperature of 80-100 °C, control the dehydration time within 2-3 hours to remove the moisture in the base oil and avoid the adverse effects of moisture on subsequent reactions and the performance of the lubricating grease;

[0010] S2: Add additives to the treated base oil. The additives include the following components and mass ratios: The antioxidant is 2,6-di-tert-butyl-p-cresol (BHT), and the addition amount is 0.5%-1.5% of the mass of the base oil; The extreme pressure and anti-wear agent is zinc dialkyldithiophosphate (ZDDP), and the addition amount is 1%-3% of the mass of the base oil; The thickener is lithium-based bentonite, and the addition amount is 5%-10% of the mass of the base oil; The anti-corrosion agent is benzotriazole (BTA), and the addition amount is 0.2%-0.8% of the mass of the base oil; The compatibilizer is maleic anhydride grafted polypropylene (MAPP), and the addition amount is 2%-5% of the mass of the base oil. Add the above additives to the base oil in sequence according to the ratio, and stir and mix for 30-60 minutes under the condition of a stirring speed of 300-500 r / min to make the additives evenly dispersed in the base oil;

[0011] S3: Transfer the base oil added with additives to a reaction kettle. Under the conditions of a reaction temperature of 120-150 °C and a reaction pressure of 0.2-0.5 MPa, control the reaction time within 3-5 hours to make each component fully react to form a lubricating grease base system with specific properties;

[0012] S4: After the reaction is completed, the reaction product is refined. By means of vacuum distillation, under the conditions of a vacuum degree of 0.01 - 0.03 MPa and a temperature of 180 - 220 °C, low-boiling impurities and incompletely reacted substances generated during the reaction are removed. The refined lubricating grease is filtered through a multi-layer filtration device. The filtration device successively includes a coarse filtration layer, a fine filtration layer, and an ultrafiltration layer. The mesh number of the coarse filtration layer is 100 - 200 meshes, the mesh number of the fine filtration layer is 300 - 500 meshes, and the pore diameter of the ultrafiltration layer is 0.1 - 0.5 μm to ensure the purity of the lubricating grease and improve its service performance;

[0013] S5: Quality inspection is carried out on the filtered lubricating grease. The inspection items include but are not limited to appearance, penetration, dropping point, water resistance, extreme pressure performance, and compatibility with PC and ABS materials.

[0014] Preferably, in the step S1, the viscosity index of the polyalphaolefin (PAO) is not less than 120, and the kinematic viscosity at 40 °C is 30 - 50 mm 2 / s; the sulfur content of the paraffin-based mineral oil is less than 0.05%, and the nitrogen content is less than 0.01%.

[0015] Preferably, in the step S2, the purity of the 2,6-di-tert-butyl-p-cresol (BHT) is not less than 99%, the phosphorus content of the zinc dialkyldithiophosphate (ZDDP) is 8% - 12%, the particle size of the lithium-based bentonite is 200 - 400 meshes, the purity of the benzotriazole (BTA) is not less than 98%, and the grafting rate of the maleic anhydride grafted polypropylene (MAPP) is 1% - 3%.

[0016] Preferably, in the step S3, nitrogen is used as the protective gas during the reaction process, and the nitrogen flow rate is 10 - 20 L / h to prevent the reaction system from being oxidized at high temperature.

[0017] Preferably, in the step S4, during the vacuum distillation process, the distillation time is 2 - 4 hours; the filtration area ratio of the coarse filtration layer, the fine filtration layer, and the ultrafiltration layer in the multi-layer filtration device is 1:2:3.

[0018] Preferably, in the step S5, for the appearance inspection, the lubricating grease is required to have uniform color and no obvious impurities; the penetration is in the range of 265 - 295 (0.1 mm); the dropping point is not less than 180 °C; the water resistance is tested by the water spray loss test, and the water spray loss does not exceed 5%; the extreme pressure performance is tested by a four-ball tester, and the maximum non-seizure load (PB value) is not less than 800 N; for the compatibility test with PC and ABS materials, they are placed in an environment of 70 °C and 80% humidity for 72 hours, and there are no obvious cracking and deformation phenomena on the PC and ABS materials.

[0019] A lubricating grease for preventing cracking of PC and ABS mixtures, prepared by the above-described preparation method, which is applied to the lubrication of plastic products made of PC and ABS mixtures.

[0020] Technical effects and advantages of the present invention:

[0021] 1. Through poly-α-olefin and deeply refined paraffin-based mineral oil, combined with targeted additives such as maleic anhydride grafted polypropylene as a compatibilizer, the compatibility of the lubricating grease with PC and ABS materials is effectively enhanced, avoiding the problem of material cracking caused by the penetration of the lubricating grease, and greatly improving the quality and reliability of plastic products made of PC and ABS mixtures.

[0022] 2. The antioxidant 2,6-di-tert-butyl-p-cresol added can effectively inhibit the oxidation of the lubricating grease during use and extend its service life; the extreme pressure and anti-wear agent zinc dialkyldithiophosphate endows the lubricating grease with good extreme pressure and anti-wear properties, enabling it to play a stable lubricating role under high-load and high-pressure working conditions; the thickener lithium-based bentonite ensures that the lubricating grease has an appropriate consistency to meet the use requirements of different scenarios; the anti-corrosion agent benzotriazole (BTA) can prevent the corrosion of metal parts and protect the equipment.

[0023] 3. Low-boiling impurities and incompletely reacted substances are removed by vacuum distillation, and then filtered through a multi-layer filtration device, ensuring the high purity of the lubricating grease, further improving its use performance, and reducing the adverse effects of impurities on the lubrication effect and materials. Detailed implementation manners

[0024] Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0025] Example 1

[0026] Selection and treatment of base oil: Accurately weigh poly-α-olefin (PAO) so that its mass ratio in the base oil is 30%, the viscosity index of PAO is 120, and the kinematic viscosity at 40 °C is 30 mm 2 / s. Weigh the deeply refined paraffin-based mineral oil, accounting for 70% of the mass of the base oil. The sulfur content of this mineral oil is 0.04% and the nitrogen content is 0.008%. After mixing the two, transfer them to a vacuum drying device and dehydrate for 2 hours under the conditions of a vacuum degree of 0.05 MPa and a temperature of 80 °C.

[0027] Additive compounding: Prepare 2,6-di-tert-butyl-p-cresol (BHT) with a purity of 99%, and the addition amount is 0.5% of the mass of the base oil; zinc dialkyldithiophosphate (ZDDP) with a phosphorus content of 8%, and the addition amount is 1% of the mass of the base oil; lithium-based bentonite with a particle size of 200 mesh, and the addition amount is 5% of the mass of the base oil; benzotriazole (BTA) with a purity of 98%, and the addition amount is 0.2% of the mass of the base oil; maleic anhydride grafted polypropylene (MAPP) with a grafting rate of 1%, and the addition amount is 2% of the mass of the base oil. Add these additives to the treated base oil in sequence, and stir and mix for 30 minutes under the condition of a stirring speed of 300 r / min.

[0028] Mixing reaction: Pour the base oil added with additives into the reaction kettle, and introduce nitrogen into the reaction kettle as a protective gas, with a nitrogen flow rate of 10 L / h. Set the reaction temperature to 120 °C, the reaction pressure to 0.2 MPa, and control the reaction time to 3 hours to promote the full reaction of each component to form a lubricating grease base system.

[0029] Refining and filtration: After the reaction, carry out vacuum distillation refining on the reaction product. Under the conditions of a vacuum degree of 0.01 MPa and a temperature of 180 °C, distill for 2 hours to remove low-boiling impurities and incompletely reacted substances. The refined lubricating grease is filtered through a multi-layer filtration device. The mesh number of the coarse filtration layer filter screen is 100 mesh, the mesh number of the fine filtration layer filter screen is 300 mesh, the pore size of the ultrafiltration layer filter screen is 0.1 μm, and the filtration area ratio of the coarse filtration layer, the fine filtration layer and the ultrafiltration layer is 1:2:3.

[0030] Quality inspection and packaging: Conduct quality inspection on the filtered lubricating grease. Appearance inspection shows uniform color and no obvious impurities; the penetration test result is 265 (0.1 mm); the dropping point is 180 °C; test the water resistance through the water spray loss test, and the water spray loss is 4%; use a four-ball tester to test the extreme pressure performance, and the maximum non-seizure load (PB value) is 800 N; conduct a compatibility test on PC and ABS materials in an environment of 70 °C and 80% humidity. After placing for 72 hours, there are no obvious cracking and deformation phenomena on the PC and ABS materials. After passing the inspection, package the lubricating grease in a plastic bucket with corrosion resistance and good sealing performance.

[0031] Example 2

[0032] Base oil selection and treatment: Weigh polyalphaolefin (PAO) so that its mass proportion in the base oil is 40%. The viscosity index of PAO is 130, and the kinematic viscosity at 40 °C is 40 mm 2 / s. Weigh paraffinic mineral oil, accounting for 60% of the mass of the base oil. The sulfur content of this mineral oil is 0.03% and the nitrogen content is 0.006%. After mixing, dehydrate for 2.5 hours under the conditions of a vacuum degree of 0.06 MPa and a temperature of 90 °C.

[0033] Additive compounding: Prepare BHT with a purity of 99.5%, and the addition amount is 1% of the mass of the base oil; ZDDP with a phosphorus content of 10%, and the addition amount is 2% of the mass of the base oil; lithium-based bentonite with a particle size of 300 mesh, and the addition amount is 7% of the mass of the base oil; BTA with a purity of 98.5%, and the addition amount is 0.5% of the mass of the base oil; MAPP with a grafting rate of 2%, and the addition amount is 3% of the mass of the base oil. Stir and mix for 45 minutes under the condition of a stirring speed of 400 r / min.

[0034] Mixing reaction: Transfer the base oil to the reaction kettle, and introduce nitrogen for protection, with a nitrogen flow rate of 15 L / h. Set the reaction temperature at 135 °C, the reaction pressure at 0.3 MPa, and the reaction time at 4 hours.

[0035] Refining and filtration: Carry out vacuum distillation under the conditions of a vacuum degree of 0.02 MPa and a temperature of 200 °C for 3 hours. During filtration, the mesh number of the coarse filter layer is 150 mesh, the mesh number of the fine filter layer is 400 mesh, and the pore size of the ultrafiltration layer is 0.3 μm. The filtration area ratio of each layer is 1:2:3.

[0036] Quality inspection and packaging: The appearance inspection shows uniform color and no impurities; the penetration is 280 (0.1 mm); the dropping point is 190 °C; the water washout loss is 3%; the PB value is 900 N; there is no abnormality in the compatibility test of PC and ABS materials. After passing the inspection, it is packaged in metal drums.

[0037] Example 3

[0038] Base oil selection and treatment: The mass fraction of polyalphaolefin (PAO) in the base oil is 50%, its viscosity index is 140, and the kinematic viscosity at 40 °C is 50 mm 2 / s. The paraffinic mineral oil accounts for 50% of the mass of the base oil, with a sulfur content of 0.02% and a nitrogen content of 0.004%. Dehydrate for 3 hours under the conditions of a vacuum degree of 0.08 MPa and a temperature of 100 °C.

[0039] Additive compounding: Use BHT with a purity of 99.8%, and the addition amount is 1.5% of the mass of the base oil; ZDDP with a phosphorus content of 12%, and the addition amount is 3% of the mass of the base oil; lithium-based bentonite with a particle size of 400 mesh, and the addition amount is 10% of the mass of the base oil; BTA with a purity of 99%, and the addition amount is 0.8% of the mass of the base oil; MAPP with a grafting rate of 3%, and the addition amount is 5% of the mass of the base oil. Stir at a speed of 500 r / min and stir and mix for 60 minutes.

[0040] Mixing reaction: Introduce nitrogen into the reaction kettle with a flow rate of 20 L / h. The reaction temperature is 150 °C, the reaction pressure is 0.5 MPa, and the reaction time is 5 hours.

[0041] Refining and Filtration: Carry out vacuum distillation for 4 hours under the conditions of a vacuum degree of 0.03 MPa and a temperature of 220 °C. During filtration, the mesh number of the coarse filter layer is 200 meshes, the mesh number of the fine filter layer is 500 meshes, the pore size of the ultrafiltration layer is 0.5 μm, and the filtration area ratio is 1:2:3.

[0042] Quality Inspection and Packaging: Good appearance; Penetration 295 (0.1 mm); Drop point 200 °C; Water washout loss 2%; PB value 1000 N; Good compatibility between PC and ABS materials. After passing the inspection, it is packaged and stored.

[0043] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a lubricating grease for preventing PC and ABS mixture from cracking, characterized in that: The following steps are involved: S1: Select a suitable base oil, the base oil includes synthetic oil and mineral oil, wherein the synthetic oil is polyalphaolefin (PAO), which accounts for 30%-50% of the base oil by mass, and the mineral oil is a deeply refined paraffin-based mineral oil, which accounts for 50%-70% of the base oil by mass. The selected base oil is dehydrated, and the dehydration time is controlled to be 2-3 hours under the conditions of vacuum degree of 0.05-0.08MPa and temperature of 80-100°C to remove moisture in the base oil to avoid adverse effects of moisture on subsequent reactions and lubricating grease performance; S2: Add additives to the treated base oil, the additives include the following components and mass proportions: antioxidant is 2,6-di-tert-butyl-p-cresol (BHT), the addition amount is 0.5%-1.5% of the base oil mass; extreme pressure anti-wear agent is zinc dialkyl dithiophosphate (ZDDP), the addition amount is 1%-3% of the base oil mass; thickener is lithium bentonite, the addition amount is 5%-10% of the base oil mass; anti-corrosion agent is benzotriazole (BTA), the addition amount is 0.2%-0.8% of the base oil mass; compatibilizer is maleic anhydride grafted polypropylene (MAPP), the addition amount is 2%-5% of the base oil mass. Add the above additives to the base oil in proportion, and stir and mix for 30-60 minutes at a stirring speed of 300-500r / min to make the additives evenly dispersed in the base oil; S3: transferring the base oil to which the additives have been added to a reactor, and controlling the reaction time to be 3-5 hours under the conditions of a reaction temperature of 120-150° C. and a reaction pressure of 0.2-0.5 MPa, so that each component reacts fully to form a lubricating grease base system with specific properties; S4: After the reaction is completed, the reaction product is refined by vacuum distillation at a vacuum degree of 0.01-0.03MPa and a temperature of 180-220°C to remove low-boiling impurities and unreacted substances generated during the reaction. The refined lubricating grease is filtered through a multi-layer filtration device, which includes a coarse filtration layer, a fine filtration layer and an ultrafiltration layer in sequence. The coarse filtration layer has a mesh size of 100-200 mesh, the fine filtration layer has a mesh size of 300-500 mesh, and the ultrafiltration layer has a mesh size of 0.1-0.5μm, so as to ensure the purity of the lubricating grease and improve its performance; S5: Perform quality inspection on the filtered lubricating grease. Inspection items include but are not limited to appearance, cone penetration, dropping point, water resistance, extreme pressure performance, and compatibility with PC and ABS materials.

2. The method for preparing lubricating grease for preventing cracking of PC and ABS mixture according to claim 1, characterized in that: In step S1, the viscosity index of the poly-alpha-olefin (PAO) is not less than 120, and the kinematic viscosity at 40°C is 30-50 mm 2 / s; the sulfur content of the paraffin-based mineral oil is less than 0.05%, and the nitrogen content is less than 0.01%.

3. The method for preparing lubricating grease for preventing PC and ABS mixture from cracking according to claim 1, characterized in that: In the step S2, the purity of the 2,6-di-tert-butyl-p-cresol (BHT) is not less than 99%, the phosphorus content of the zinc dialkyl dithiophosphate (ZDDP) is 8%-12%, the particle size of the lithium bentonite is 200-400 mesh, the purity of the benzotriazole (BTA) is not less than 98%, and the grafting rate of the maleic anhydride grafted polypropylene (MAPP) is 1%-3%.

4. The method for preparing lubricating grease for preventing PC and ABS mixture from cracking according to claim 1, characterized in that: In step S3, nitrogen is used as a protective gas during the reaction, and the nitrogen flow rate is 10-20 L / h to prevent the reaction system from being oxidized at high temperature.

5. The method for preparing lubricating grease for preventing PC and ABS mixture from cracking according to claim 1, characterized in that: In the step S4, during the reduced pressure distillation process, the distillation time is 2-4 hours; the filtration area ratio of the coarse filtration layer, the fine filtration layer and the ultrafiltration layer in the multi-layer filtration device is 1:2:

3.

6. The method for preparing lubricating grease for preventing PC and ABS mixture from cracking according to claim 1, characterized in that: In step S5, the appearance inspection requires that the lubricating grease has uniform color and no obvious impurities; the cone penetration is within the range of 265-295 (0.1mm); the dropping point is not less than 180°C; the water resistance is tested by water runoff loss, and the water runoff loss does not exceed 5%; the extreme pressure performance is tested by a four-ball testing machine, and the maximum no-seizure load (PB value) is not less than 800N; the compatibility test with PC and ABS materials is tested, and the PC and ABS materials are placed in an environment of 70°C and 80% humidity for 72 hours, and there is no obvious cracking or deformation of the PC and ABS materials.

7. A lubricating grease for preventing PC and ABS mixture from cracking prepared by the preparation method according to any one of claims 1 to 6, characterized in that: This lubricating grease is used for lubrication of plastic products made of PC and ABS mixture.