Method for preparing linear phenol-aldehyde resin

A kind of novolac resin and aldehyde technology, which is applied in the field of novolac resin preparation to achieve the effect of low softening point and high fluidity

Active Publication Date: 2014-12-24
营口圣泉高科材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, there is no relevant research on how to increase the content of oligomers and improve the flow properties of the resin in the structure design of novolac resin

Method used

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  • Method for preparing linear phenol-aldehyde resin
  • Method for preparing linear phenol-aldehyde resin
  • Method for preparing linear phenol-aldehyde resin

Examples

Experimental program
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Embodiment 1

[0035] Add 500g of phenol, 151g of formaldehyde (37%), and 10g of oxalic acid into a stirred 1000ml four-necked flask with a condenser and mix them. The pH of the mixed solution was 1.5. Raise the temperature to reflux at 100°C, the conversion rate of formaldehyde reaches 90%, add sodium hydroxide at 85°C, adjust the pH to 6.5, and add 65g of formaldehyde (37%). The temperature was raised to reflux for 2 hours. Continue to heat up and dehydrate until the temperature reaches 160° C., and then the novolac resin of Example 1 can be obtained.

Embodiment 2

[0037] Add 500g of phenol, 181 formaldehyde (37%), and 10g of oxalic acid into a stirred 1000ml four-necked flask with a condenser and mix them. The pH of the mixed solution was 1.7. Raise the temperature to reflux at 100°C, the conversion rate of formaldehyde reaches 89%, add sodium hydroxide at 85°C, adjust the pH to 6.5, and add 77g of formaldehyde (37%). The temperature was raised to reflux for 2 hours. Continue to heat up and dehydrate until the temperature reaches 160° C., and then the novolac resin of Example 2 can be obtained.

Embodiment 3

[0039] Add 500g of phenol, 211g of formaldehyde (37%), and 10g of oxalic acid into a stirred 1000ml four-necked flask with a condenser and mix them. The pH of the mixed solution was 1.9. Raise the temperature to reflux at 100°C, the conversion rate of formaldehyde reaches 90%, add sodium hydroxide at 85°C, adjust the pH to 6.5, and add 91g of formaldehyde (37%). The temperature was raised to reflux for 2 hours. Continue to heat up and dehydrate until the temperature reaches 160° C., and then the novolac resin of Example 3 can be obtained.

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Abstract

The invention relates to the technical field of phenol-aldehyde resin and particularly relates to a method for preparing linear phenol-aldehyde resin. The method comprises the following steps: mixing phenol with a first part of aldehyde, adjusting the pH value to1-3 and heating until a reflux reaction is carried out to obtain a mixed solution; adjusting the pH value of the mixed solution to 4-9, adding the residual aldehyde, after the reaction is completed, heating and dehydrating until the temperature is 160 DEG C to obtain the linear phenol-aldehyde resin, wherein the addition amount of the first part of aldehyde accounts for 30-75% of total amount of the aldehyde. By virtue of control of the in-batch addition amount of aldehyde and the pH value of the reaction process, the resin with high content of oligomer and wide molecular weight distribution of resin is obtained; under the condition that the molecular weights are similar, the linear phenol-aldehyde resin with low softening point and high fluidity can be obtained by virtue of the method disclosed by the invention compared with the resin obtained by virtue of the original process.

Description

technical field [0001] The invention relates to the technical field of phenolic resins, in particular to a preparation method of novolac resins. Background technique [0002] Phenolic resin is a general term for resins produced by the reaction of phenols and aldehydes in the presence of catalysts. It is the earliest polymer material produced industrially. It has excellent mechanical properties, ablation resistance, and electrical insulation properties. Widely used in molding compound, friction material, casting, mold material and other fields. [0003] Novolac resins are obtained by reacting phenols and aldehydes in the presence of acidic catalysts. The molar ratio of phenols and aldehydes is 1:0.5-0.8. Under the catalyst, the phenols and aldehydes firstly react in a homogeneous phase, and then transform into a heterogeneous reaction with the deepening of the reaction, reaching a certain reaction end point. High-temperature dehydration or supplemented by vacuum can obtai...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): C08G8/10C08K3/04C08G8/04C08G8/08C08G8/20C08G8/22
Inventor唐一林刘翠华李枝芳袁善菊董强
Owner营口圣泉高科材料有限公司