Two-stage porous polyimide material, preparation method thereof, two-stage porous polyimide retainer and application of two-stage porous polyimide retainer

A technology of porous polyimide and polyimide, which is applied in the field of polymer cages, can solve the problems of fast oil output, uneven pressure of materials, and uneven distribution of pore structure, so as to improve mechanical strength and facilitate molding , uniform pressure effect

Active Publication Date: 2021-10-19
LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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Problems solved by technology

The particle size of YS-20 is about 10-50 μm, and the particles are relatively large. Using the traditional four-column hydraulic press combined with the preparation process of limited sintering (ZL200410010165.3, ZL201310480892.5), the average pore diameter of the obtained pores is all within 1.0 μm or more, and the average pore size directly determines the capillary action of the through pores and affects the outward throwing and inward suction of the implicit lubricating oil. Therefore, the porous polyimide prepared by the existing YS-20 maintains The lubricating oil can be thrown out at a speed of 3000rpm, and when the bearing speed is further increased, the oil output rate is too fast, causing the lubricating oil to be thrown out from the inside of the cage in a short period of time, reducing the supply of the bearing cage oil life
[0005] The existing porous polyimide cage materials all have a single-stage pore structure, that is, the pore size distribution after molding is only concentrated in a certain range of values, which results in larger pore sizes being only suitable for low-speed running bearings, and smaller pore sizes The aperture is only suitable for high-speed running bearings, that is, the speed applicability of the porous polyimide bearing cage is relatively single
At the same time, the traditional preparation process is one-way or two-way pressure, and the material is not evenly pressed, which directly leads to uneven distribution of pore structure, which affects key indicators such as mechanical strength, oil-containing performance and oil-supply performance of porous materials.

Method used

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  • Two-stage porous polyimide material, preparation method thereof, two-stage porous polyimide retainer and application of two-stage porous polyimide retainer
  • Two-stage porous polyimide material, preparation method thereof, two-stage porous polyimide retainer and application of two-stage porous polyimide retainer
  • Two-stage porous polyimide material, preparation method thereof, two-stage porous polyimide retainer and application of two-stage porous polyimide retainer

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[0031] The invention provides a method for preparing a two-stage porous polyimide material, comprising the following steps:

[0032] Dissolving rigid aromatic diamines, flexible aromatic diamines and aromatic dibasic acid anhydrides in polar aprotic solvents, performing polycondensation reactions to obtain polyamic acid mixed solutions;

[0033] Mixing the polyamic acid mixed solution with a dehydrating agent to carry out imidization reaction to obtain polyimide molding powder;

[0034] The polyimide molding powder is subjected to cold isostatic pressing to obtain a cold-pressed blank;

[0035] The cold-pressed blank is subjected to hot isostatic pressing to obtain a polyimide material with two-stage pores.

[0036] In the present invention, unless otherwise specified, the preparation materials used are commercially available products well known to those skilled in the art.

[0037] In the invention, rigid aromatic diamine, flexible aromatic diamine and aromatic dibasic acid...

Embodiment 1

[0065] At normal temperature and pressure, in a nitrogen protective atmosphere, add 0.25mol 4,4'-diaminodiphenyl ether (ODA) and 2000g N-methyl Pyrrolidone (NMP), stirring rapidly for 0.5 hours, ODA was completely dissolved to obtain a homogeneous solution, slowly adding 0.25mol biphenyltetracarboxylic dianhydride (BPDA) powder in batches, and carrying out the first polycondensation reaction at a stirring speed of 100rpm for 12h to obtain Polyamic acid solution with rigid structure; add 0.75mol 1,4-bis(4-aminophenoxy)benzene (APB) and 1300g NMP, after stirring again to completely dissolve, add 0.75mol BPDA powder in batches, add 81g Solvent NMP, make the quality of NMP in the reaction system be 6 times of ODA, APB and BPDA three kinds of monomer total masses (being that mass concentration is 14.29wt%), under room temperature, carry out the second polycondensation reaction 12 hours under 100rpm stirring speed , to obtain a polyamic acid mixed solution;

[0066] Add 1183.4g tol...

Embodiment 2

[0077] At normal temperature and pressure, in a nitrogen protective atmosphere, add 0.25mol ODA and 1200g N,N-dimethylformamide (DMF) to a three-necked flask equipped with mechanical stirring, a thermometer and a condenser, and stir rapidly for 0.5 Hours, ODA is completely dissolved to obtain a homogeneous solution, slowly add 0.25mol pyromellitic anhydride (PMDA) powder in batches, carry out the first polycondensation reaction 18h at a stirring speed of 200rpm, obtain a polyamic acid solution with a rigid structure; add 0.75molAPB, stir to make APB fully dissolve, then add 0.75mol PMDA powder in batches, add 262.2g solvent DMF, make the quality of DMF in the reaction system be 3 times of the three monomers of ODA, APB and PMDA (i.e. mass concentration 25.0wt%), at room temperature, the second polycondensation reaction was carried out at a stirring speed of 200rpm for 18 hours to obtain a polyamic acid mixed solution;

[0078] Add 390g of benzene to the polyamic acid mixed sol...

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Abstract

The invention provides a two-stage porous polyimide material, a preparation method thereof, a two-stage porous polyimide retainer and application of the two-stage porous polyimide retainer, and relates to the technical field of polymer retainers. The preparation method of the two-stage porous polyimide material provided by the invention comprises the following steps: dissolving rigid aromatic diamine, flexible aromatic diamine and aromatic dicarboxylic anhydride in a polar aprotic solvent, and carrying out condensation polymerization to obtain a polyamide acid mixed solution; mixing the polyamide acid mixed solution with a dehydrating agent, and carrying out imidization reaction to obtain polyimide molding powder; performing cold isostatic pressing on the polyimide molding powder to obtain a cold pressed blank; and carrying out hot isostatic pressing on the cold-pressed blank to obtain the two-stage pore polyimide material. A rigid-flexible monomer combination mode is adopted, the prepared two-stage porous polyimide material can realize intelligent regulation and control of oil containing and oil discharging according to different rotating speeds, the pressurization mode is more uniform, forming is convenient, and the preparation method is suitable for large-scale production.

Description

technical field [0001] The invention relates to the technical field of polymer cages, in particular to a two-stage porous polyimide material and a preparation method thereof, a two-stage porous polyimide cage and applications thereof. Background technique [0002] As the core component of precision control systems such as main bearings of high-speed precision machine tools, the physical and chemical properties and lubrication characteristics of polymer bearing cage materials directly determine the running accuracy and service life of spindle bearings. [0003] The porous polyimide bearing cage has a through internal pore structure, which can not only isolate the rolling elements from each other, but also use its internal pore structure to contain lubricating oil, so as to realize long-term storage and controllable supply of lubricating oil. When the bearing is running at high speed, the lubricating oil adsorbed in the pores will be thrown out under the action of centrifugal ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B29C43/10C08G73/10C08L79/08F16C33/38F16C33/46B29L31/04
CPCB29C43/10B29C43/003C08G73/1071C08G73/1007C08L79/08F16C33/38F16C33/46B29C2043/106B29L2031/04
Inventor 陶立明郭丽和赵普杨丽君王廷梅王齐华
Owner LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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