Preparation method of modified phenolic resin binder for casting

A technology of phenolic resin and binder, which is applied in the field of preparation of modified phenolic resin binder for foundry, can solve the problems of high binder cost, poor reusability, poor performance, etc., and achieve low cost and economical use The effect of reducing the amount of formaldehyde released

Inactive Publication Date: 2009-12-23
FUZHOU UNIV
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a method for preparing a modified phenolic resin binder for casting, which solves the problems of high cost, heavy pollution, poor reusability, and poor performance of the casting binder in the prior art. The preparation process of the present invention Simple, prepared adhesive with high strength, good process performance, high bonding strength, good storage stability, etc.

Method used

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  • Preparation method of modified phenolic resin binder for casting
  • Preparation method of modified phenolic resin binder for casting
  • Preparation method of modified phenolic resin binder for casting

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preparation example Construction

[0022] (2) Preparation of modified phenolic resin binder

[0023] Mix phenol and formaldehyde, under the action of catalyst, keep warm for 1-5h, then add the hydroxymethylated lignin obtained in step (1), continue to react for 1-5h, add organic bentonite, stir for 0.3-1.5h, and obtain modified phenolic resin binder.

[0024] The dosage ratio of formaldehyde and lignin in step (1) is 1:2-1:8, calculated by mass ratio.

[0025] The mass concentration of the NaOH solution in the step (1) is 3%-15%; the volume consumption of the NaOH solution is calculated by dissolving 1g of lignin in 8-20mL of the NaOH solution.

[0026] In the step (1), the constant temperature reaction temperature is 30-90°C.

[0027] The mass ratio of phenol, formaldehyde and hydroxymethylated lignin in step (2) is 2:2:1-8:8:1.

[0028] The catalyst used in the step (2) is sodium hydroxide or oxalic acid; the amount of sodium hydroxide or oxalic acid is 0.5% to 1.5% of the phenol mass.

[0029] In step (2...

Embodiment 1

[0033] (1) Raw materials: lignin, Jiangsu Jingwei Technology Co., Ltd.;

[0034] Other raw materials are commercially available common commodity grade.

[0035] (2) The specific preparation method is as follows:

[0036] ①Hydroxymethylation modification of lignin

[0037] Dissolve 12g of lignin in 120mL of NaOH solution with a mass concentration of 7%, heat and stir, slowly drop in 2g of formaldehyde, and react at a constant temperature of 50°C for 2h; then pour the reaction solution into deionized water, stir and add dropwise % hydrochloric acid until the pH value is 3, and the precipitated solid is suction-filtered, washed repeatedly until the washing liquid is neutral, and vacuum-dried at 60°C to obtain hydroxymethylated lignin.

[0038] ② Preparation of modified phenolic resin binder

[0039] Mix 30g of phenol and 30g of formaldehyde, add 0.3g of sodium hydroxide, keep warm at 65°C for 2h, then add 10g of the hydroxymethylated lignin obtained in step (1), continue the r...

Embodiment 2

[0047] (1) Raw materials: lignin, Jiangsu Jingwei Technology Co., Ltd.;

[0048] Other raw materials are commercially available common commodity grade.

[0049] (2) The specific preparation method is as follows:

[0050] ①Hydroxymethylation modification of lignin

[0051] Heat and stir 15g of lignin with 230mL of NaOH solution with a mass concentration of 13%, slowly drop in 5g of formaldehyde, and react at a constant temperature of 80°C for 4h; then pour the reaction solution into deionized water, stir and add dropwise hydrochloric acid with a mass concentration of 13% When the pH value is 4, the precipitated solid is suction-filtered, washed repeatedly until the washing liquid is neutral, and vacuum-dried at 60° C. to obtain hydroxymethylated lignin.

[0052] ② Preparation of modified phenolic resin binder

[0053] Mix 30g of phenol and 30g of formaldehyde, add 0.3g of oxalic acid, keep warm at 85°C for 4h, then add 5g of the hydroxymethylated lignin obtained in step (1),...

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Abstract

The invention provides a preparation method of a modified phenolic resin binder for casting, belonging to the technical field of binder for casting. The preparation method comprises the following steps of: carrying out hydroxymethylation modification to lignin, then carrying out cocondensation of hydroxymethylation lignin, phenol and formaldehyde, finally adding organic bentonite for composition and preparing the modified phenolic resin binder. The lignin molecule has phenolic hydroxyl and aldehyde group, uses lignin, not only improves the property of the binder, but also saves using amount of the phenol, reduces the releasing amount of formaldehyde and achieves the purposes of fully utilizing waste and protecting environment. Simultaneously, the adding of the organic bentonite further improves the strength and stability of the binder. The binder product has high strength and good comprehensive performance, can replace synthetic fat oil or partial resin sand to manufacture II level mud core, have the advantages of low cost, low content of free formaldehyde and good storage and stability and the like, have obvious economic benefit and can be widely applied in the casting field.

Description

technical field [0001] The invention belongs to the technical field of casting binders, and more specifically relates to a preparation method of a modified phenolic resin binder for castings. Background technique [0002] The foundry binder and its application technology are the main factors affecting the sand casting production environment and the performance of the mold and core sand, and the foundry binder is different from other binders in terms of performance, economy and environment. On the other hand, it has its unique requirements, so according to the requirements of casting binder, it is imperative to develop a new type of non-toxic, non-polluting, excellent comprehensive performance casting binder and its modeling and core-making process. Traditional casting binders such as resin, tung oil, water glass, etc. have their own advantages and application ranges, but there are also some problems such as high cost of resin, complicated sand mixing process, and strong irri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22C1/22
Inventor 林锦贤郑玉婴
Owner FUZHOU UNIV
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