Preparation method for thermosetting phenolic resin tensile sample with high solvent content

A technology of phenolic resin and solvent content, applied in the field of composite materials, can solve the problems of phenolic resin matrix brittleness, difficulty, casting body fracture, etc., achieve good mechanical properties and improve the success rate

Pending Publication Date: 2019-01-18
TIANJIN POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Phenolic resin is usually pre-polymerized by phenol and formaldehyde under the conditions of a catalyst to form a low molecular weight mixture, and then cured at elevated temperature. The methylol and hydroxyl groups in the phenolic resin molecule undergo further dehydration reactions, and finally produce a cured phenolic resin. , but it has the following disadvantages in the process of solidifying into a casting body. First, the phenolic resin solution generally contains ethanol solvent. The solvent will volatilize during the heating and curing process, causing pores to form on the surface and inside of the casting body, and there are many defects. Second, The dehydration reaction is mainly carried out during the curing and molding process of phenolic resin. As the experiment progresses, a large amount of small molecular substances such as water and formaldehyde will be released, and the volatilization of these small molecules will also cause pores and affect the performance of the casting body.
Third, the phenolic resin matrix is ​​brittle, has a large shrinkage rate, and is easy to break when the mold is opened, which destroys the integrity of the casting body and cannot test the mechanical properties of the casting body
Fourth, in the current national standard GB / T 2567-2008 for testing the tensile properties of resin castings, the size of the casting samples specified is relatively long. It is more difficult to form a cast tensile specimen
Although the patent application number 201710127299.0 proposes a method for preparing a phenolic resin casting, this method cannot remove a large amount of solvent, and the casting is likely to break due to pulling during the demoulding process

Method used

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  • Preparation method for thermosetting phenolic resin tensile sample with high solvent content
  • Preparation method for thermosetting phenolic resin tensile sample with high solvent content
  • Preparation method for thermosetting phenolic resin tensile sample with high solvent content

Examples

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Effect test

example 1

[0048] The preparation process of the thermosetting phenolic resin tensile specimen casting body is as follows: Take 80g of magnesium phenolic resin and slowly heat it up from room temperature to 90°C at a heating rate of 2°C / min. 8h, the solid content reaches 60%, and the curing degree reaches 65%. Put the phenolic resin in the semi-gel state into the freezer and keep it frozen at minus 10°C for 8 hours. The stretching mold coated with the release agent is preheated at a constant temperature of 120°C for 3 hours, and then take 18g of powdered phenolic resin Spread the phenolic resin evenly into the drawing mold, fully melt at 120°C for 6 hours, close the mold and pressurize, raise the temperature to 160°C at a rate of 3°C / min under a pressure of 10MPa, cure at a constant temperature of 10h, and then disassemble at 160°C Open the mold, take out the sample, and continue to place the sample in an oven at a constant temperature of 180°C for 12 hours until it is completely cured. ...

example 2

[0051] The preparation process of the thermosetting phenolic resin tensile specimen casting body is as follows: Take 100g of magnesium phenolic resin and slowly heat it up from room temperature to 100°C at a heating rate of 4°C / min. After 6 hours, the solid content reached 68%, and the curing degree reached 69%. Put the phenolic resin in the semi-gel state into the freezer, keep it frozen at minus 15°C for 5 hours, preheat the stretching mold coated with the release agent for 6 hours at a constant temperature of 100°C, and then add 20g of powdered phenolic resin Spread the phenolic resin evenly into the drawing mold, fully melt at a constant temperature of 100°C for 12 hours, close the mold and pressurize, raise the temperature to 150°C at a rate of 2°C / min under a pressure of 10MPa, cure at a constant temperature for 15 hours, and open the mold at 150°C , Take out the sample and put it in the oven at 180°C for 6h until it is completely cured, process and polish it, and finall...

example 3

[0054] The preparation process of the thermosetting phenolic resin tensile specimen casting body is as follows: Take 120g of aminophenolic resin and slowly heat it up from room temperature to 95°C at a heating rate of 3°C / min. h, the solid content reaches 60%, and the curing degree reaches 70%. Put the phenolic resin in the semi-gel state into the freezer and keep it frozen at minus 8°C for 10 hours. The stretching mold coated with the release agent is preheated at a constant temperature of 110°C for 5 hours, and then the powdered phenolic resin The resin is uniformly spread into the drawing mold, fully melted at a constant temperature of 110°C for 10 hours, the mold is closed and pressurized, the temperature is raised to 170°C at a rate of 2°C / min under a pressure of 10MPa, the temperature is cured for 9 hours, and the mold is opened at a temperature of 170°C. Take out the sample and put it in an oven at 190°C for 5 hours until it is completely cured, process and polish it, a...

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Abstract

The invention relates to a preparation technology for a thermosetting phenolic resin casting matrix with high solvent content and is suitable for mold design of casting matrix tensile samples. A four-frame combined molding chamber structure is adopted for reasonably designing a phenolic resin tensile sample mold. Reaction temperature and reaction time are strictly controlled by controlling a curing reaction process; the phenolic resin is subjected to pre-gelling treatment under the conditions of certain temperature and certain time till the resin is under a semi-gel state; most micro-molecules, such as water and formaldehyde, generated from condensation polymerization are removed from the resin under the semi-gel state, and meanwhile, the ethyl alcohol solvent contained in the phenolic resin is removed and an excellent binding force between resin and resin is kept; the phenolic resin under the semi-gel state is put into a mold for further curing, so as to finally acquire a transparentphenolic resin tensile sample. According to the invention, the problems of more defects, easiness in breaking while de-molding and the like of phenolic resin tensile sample can be solved, and the tensile sample with high success rate and few defects can be acquired.

Description

technical field [0001] The invention relates to the field of composite materials, and relates to a method for preparing a thermosetting phenolic resin casting body with high solvent content and a mold design applicable to the tensile sample of the casting body, which can be used to test and characterize the tensile properties of phenolic resin, and is a phenolic resin The application provides basic data. Background technique [0002] Phenolic resin has high mechanical strength, excellent heat resistance, electrical insulation and good dimensional stability, as well as the inherent flame retardancy, burning resistance and low smoke rate of the resin. Because of its unique characteristics, it is often selected as one of the resin matrix materials for military use. Phenolic resin is usually pre-polymerized by phenol and formaldehyde under the conditions of a catalyst to form a low molecular weight mixture, and then cured at elevated temperature. The methylol and hydroxyl group...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B29C39/42B29C39/26G01N1/28
CPCG01N1/28B29C39/26B29C39/42
Inventor 王伟伟张国利李昊陈光伟史晓平王志鹏代彦彦
Owner TIANJIN POLYTECHNIC UNIV
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