CN110862500A - Preparation method of furan resin with low nitrogen and low free furfuryl alcohol - Google Patents
Preparation method of furan resin with low nitrogen and low free furfuryl alcohol Download PDFInfo
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- CN110862500A CN110862500A CN201911187571.XA CN201911187571A CN110862500A CN 110862500 A CN110862500 A CN 110862500A CN 201911187571 A CN201911187571 A CN 201911187571A CN 110862500 A CN110862500 A CN 110862500A
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- furfuryl alcohol
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- furan resin
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G16/00—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00
- C08G16/02—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes
- C08G16/025—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes with heterocyclic organic compounds
- C08G16/0256—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes with heterocyclic organic compounds containing oxygen in the ring
- C08G16/0262—Furfuryl alcohol
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G16/00—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00
- C08G16/02—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes
- C08G16/0212—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes with acyclic or carbocyclic organic compounds
- C08G16/0218—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes with acyclic or carbocyclic organic compounds containing atoms other than carbon and hydrogen
- C08G16/0231—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes with acyclic or carbocyclic organic compounds containing atoms other than carbon and hydrogen containing nitrogen
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- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
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- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Phenolic Resins Or Amino Resins (AREA)
- Mold Materials And Core Materials (AREA)
Abstract
The invention discloses a preparation method of furan resin with low nitrogen and low free furfuryl alcohol, which belongs to the technical field of furan resin production. The method can ensure that the furan resin has the free furfuryl alcohol content of less than 25 percent, the nitrogen content of less than 3 percent and the free formaldehyde content of less than 0.1 percent when the adding amount of the furfuryl alcohol is more than 80 percent. The low nitrogen content makes the resin suitable for casting steel and cast iron, the high furfuryl alcohol content ensures the strength of sand mold, and can be used as large casting with low free furfuryl alcohol and free formaldehyde, thus greatly reducing the harm to human body.
Description
Technical Field
The invention relates to the technical field of furan resin production, in particular to a preparation method of furan resin with low nitrogen and low free furfuryl alcohol.
Background
The furan resin has the advantages of high strength, quick solidification, low gas evolution, good collapsibility and the like, and is widely applied to casting, especially the precision casting industry. In the production process of furan resin, raw materials comprise formaldehyde, furfuryl alcohol, urea and auxiliary additives, and process links in the production process have obvious influence on the utilization rate and the polymerization state of the raw materials and also have obvious influence on the service performance of products, including the adhesive strength and collapsibility of molding sand and the protection of casting environment. The lower the free amount of formaldehyde, the more beneficial the protection of workers. The use of urea enables the furan resin to be decomposed and reacted in the casting process to generate nitrogen, so that air holes are easily generated on the surface of a casting. Free furfuryl alcohol can be decomposed to generate dioxin in the casting process, and the dioxin can adversely affect the working environment of workers and the atmospheric environment of a factory, at present, the free furfuryl alcohol content in furan resin for casting sold in the market is high, the free furfuryl alcohol content in low furfuryl alcohol furan resin is over 45 percent, and furan resin with the free furfuryl alcohol content of less than 25 percent is determined as environment-friendly resin in Europe. Therefore, in recent years researchers have conducted extensive research around low formaldehyde, low nitrogen and low free furfuryl alcohol as targets.
The traditional furan resin production method comprises the steps of firstly carrying out addition reaction on formaldehyde and urea under an alkaline condition, then carrying out polycondensation reaction on the formaldehyde and the urea under an acidic condition, and finally carrying out neutralization reaction on the formaldehyde and the urea under an alkaline condition. In the process, the dosage of the urea is large, so that the nitrogen content in the furan resin is greatly improved, and the aim of reducing the nitrogen content is not favorably fulfilled. In order to overcome the defects of furan resin produced by the 'alkali-acid-alkali' process flow, CN 108687301B discloses that furfuryl alcohol is subjected to prepolymerization reaction under an acidic condition in one reaction device, formaldehyde and urea are subjected to reaction in the other reaction device, then the two reaction solutions are mixed, and finally the furan resin is produced by controlling the reaction process. The use of two sets of reaction devices increases the production link, improves the equipment cost, increases the production amount of waste water, and wastes raw materials due to the raw materials with low boiling point volatilized simultaneously in the treatment process. Under acidic (pH <3) conditions, formaldehyde and furfuryl alcohol undergo a drastic condensation addition reaction, resulting in a very small amount of methylol groups, a large amount of uronon rings, methylene bonds and ineffective intramolecular rings, which in turn results in the production of furan resins having low strength. CN 109851736A discloses a method for producing furan resin under acidic condition (pH 4.5-6) with the aid of catalyst, namely, formaldehyde and furfuryl alcohol are subjected to addition reaction at high temperature (130-150 ℃) under the action of catalyst zinc acetate, and then are subjected to reaction with auxiliary materials such as aldehyde removing agent to produce low-nitrogen furan resin. Under the acidic reaction condition, the use of the catalyst increases the cost of raw materials and the cost of a wastewater treatment link, and meanwhile, crystallization and precipitation are easy to occur in a reaction solution. To date, no method has been reported for producing furan resins with low nitrogen and low free furfuryl alcohol under acidic conditions without the addition of inorganic salt catalysts.
Disclosure of Invention
To solve the technical problems, the invention provides a preparation method of furan resin with low nitrogen and low free furfuryl alcohol, which comprises the steps of firstly carrying out heat preservation reaction on paraformaldehyde, furfuryl alcohol and furfuryl alcohol per se under an acidic condition to generate resin and furfuryl alcohol oligomers, then cooling, adding urea to react residual formaldehyde and urea to generate urea-formaldehyde resin, and then heating to generate furan resin from the urea-formaldehyde resin, the furfuryl alcohol and the furfuryl alcohol oligomers. The furan resin obtained by the method has less than 25% of free furfuryl alcohol, less than 3% of nitrogen content and less than 0.1% of free formaldehyde, and the low nitrogen content ensures that the resin is suitable for casting steel and cast iron, the high furfuryl alcohol content ensures the strength of a sand mold, a large casting can be made, the free furfuryl alcohol and the free formaldehyde are low, and the harm to a human body can be greatly reduced.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a preparation method of furan resin with low nitrogen and low free furfuryl alcohol comprises the following steps:
(1) adding solid formaldehyde and furfuryl alcohol into a reaction kettle, stirring and mixing, adjusting the pH value to 2.5-3 by using an organic acid catalyst, reacting at the temperature of 110-120 ℃, and keeping the temperature for 3 hours to obtain a polymer;
(2) cooling to 70 ℃, adjusting the pH value to 8.5 by using a sodium hydroxide solution, adding urea and a triethanolamine catalyst, stirring and mixing uniformly, heating to 85 ℃, and carrying out heat preservation reaction for 1 hour;
(3) adjusting the pH value to 7-7.5 by formic acid, adding an aldehyde removing agent and a coupling agent, stirring and mixing uniformly, and discharging to obtain the product, namely the low-nitrogen low-free furfuryl alcohol furan resin.
Preferably, the organic acid catalyst is a mixed aqueous solution of formic acid, propionic acid and maleic anhydride.
Preferably, the sodium hydroxide solution has a concentration of 30 wt%.
Preferably, the weight parts of the raw materials in each reaction stage are as follows: 8-12 parts of solid formaldehyde, 75-85 parts of furfuryl alcohol, 7-13 parts of urea, 0.5 part of triethanolamine, 1 part of aldehyde removing agent and 0.6 part of coupling agent.
Preferably, the solid formaldehyde is paraformaldehyde with low polymerization degree, and the content is 92-96 wt%.
Preferably, the coupling agent is N- (β -aminoethyl) -gamma-aminopropylmethyldimethoxysilane.
The beneficial effects of the invention are as follows:
(1) the preparation method has low nitrogen content, low free furfuryl alcohol, no dehydration process, no wastewater generation, safety and environmental protection, and is beneficial to industrial production;
(2) the pH value of the reaction solution is controlled within the range of 2.5-3 by utilizing the action of the organic acid catalyst, the reaction of formaldehyde and furfuryl alcohol for generating furfural is mild and thorough, the content of free formaldehyde in the prepared furan resin is low (< 0.1%), the use of an aldehyde removing agent is reduced, and the process cost is reduced;
(3) the pH value of the reaction solution is controlled within the range of 2.5-3 by utilizing the action of the organic acid catalyst, the self-polymerization reaction of the furfuryl alcohol is mild, the molecular weight distribution of the generated furfuryl alcohol polymer is narrow, and the strength of the furan resin is still ensured while the content of free furfuryl alcohol in the prepared furan resin is reduced to below 25%.
Detailed Description
To facilitate understanding of those skilled in the art, the present invention will be further described with reference to specific examples:
example 1:
a preparation method of furan resin with low nitrogen and low free furfuryl alcohol comprises the following steps:
(1) adding 8 parts of solid formaldehyde with the content of 92 wt% and 85 parts of furfuryl alcohol into a reaction kettle, stirring and mixing, adjusting the pH value to be 2.5-3 by using a mixed aqueous solution of formic acid, propionic acid and maleic anhydride, reacting at the temperature of 110-120 ℃, and keeping the temperature for 3 hours to obtain a polymer;
(2) cooling to 70 ℃, adjusting the pH value to 8.5 by using a 30 wt% sodium hydroxide solution, adding 7 parts of urea and 0.5 part of triethanolamine catalyst, stirring and mixing uniformly, heating to 85 ℃, and carrying out heat preservation reaction for 1 hour;
(3) adjusting the pH value to 7-7.5 by formic acid, adding 1 part of aldehyde removing agent and 0.6 part of coupling agent N- (β -aminoethyl) -gamma-aminopropylmethyldimethoxysilane, stirring and mixing uniformly, and discharging to obtain the product, namely the low-nitrogen low-free furfuryl alcohol furan resin.
Example 2:
a preparation method of furan resin with low nitrogen and low free furfuryl alcohol comprises the following steps:
(1) adding 12 parts of solid formaldehyde with the content of 96 wt% and 75 parts of furfuryl alcohol into a reaction kettle, stirring and mixing, adjusting the pH value to be 2.5-3 by using a mixed aqueous solution of formic acid, propionic acid and maleic anhydride, reacting at the temperature of 110-120 ℃, and keeping the temperature for 3 hours to obtain a polymer;
(2) cooling to 70 ℃, adjusting the pH value to 8.5 by using a 30 wt% sodium hydroxide solution, adding 13 parts of urea and 0.5 part of triethanolamine catalyst, stirring and mixing uniformly, heating to 85 ℃, and carrying out heat preservation reaction for 1 hour;
(3) adjusting the pH value to 7-7.5 by formic acid, adding 1 part of aldehyde removing agent and 0.6 part of coupling agent N- (β -aminoethyl) -gamma-aminopropylmethyldimethoxysilane, stirring and mixing uniformly, and discharging to obtain the product, namely the low-nitrogen low-free furfuryl alcohol furan resin.
Example 3:
a preparation method of furan resin with low nitrogen and low free furfuryl alcohol comprises the following steps:
(1) adding 10 parts of solid formaldehyde with the content of 94 wt% and 80 parts of furfuryl alcohol into a reaction kettle, stirring and mixing, adjusting the pH value to be 2.5-3 by using a mixed aqueous solution of formic acid, propionic acid and maleic anhydride, reacting at the temperature of 110-120 ℃, and keeping the temperature for 3 hours to obtain a polymer;
(2) cooling to 70 ℃, adjusting the pH value to 8.5 by using a 30 wt% sodium hydroxide solution, adding 10 parts of urea and 0.5 part of triethanolamine catalyst, stirring and mixing uniformly, heating to 85 ℃, and carrying out heat preservation reaction for 1 hour;
(3) adjusting the pH value to 7-7.5 by formic acid, adding 1 part of aldehyde removing agent and 0.6 part of coupling agent N- (β -aminoethyl) -gamma-aminopropylmethyldimethoxysilane, stirring and mixing uniformly, and discharging to obtain the product, namely the low-nitrogen low-free furfuryl alcohol furan resin.
The products prepared in the above examples 1 to 3 were subjected to performance tests, and the indexes thereof are shown in the following table:
| free formaldehyde/%) | Content of nitrogen/%) | Content of free furfuryl alcohol/%) | strength/Mpa | |
| Example 1 | 0.09 | 2.04 | 21.26 | 2.23 |
| Example 2 | 0.06 | 2.66 | 20.28 | 2.07 |
| Example 3 | 0.08 | 2.52 | 23.15 | 2.45 |
According to performance detection data, the furan resin prepared by the method disclosed by the invention has the advantages that the free furfuryl alcohol is less than 25%, the nitrogen content is less than 3%, the free formaldehyde is less than 0.1% while the furfuryl alcohol addition is more than 80%, and the strength of the furan resin is still ensured. The low nitrogen content makes the resin suitable for casting steel and cast iron, the high furfuryl alcohol content ensures the strength of sand mold, and can be used as large casting with low free furfuryl alcohol and free formaldehyde, thus greatly reducing the harm to human body.
The invention discloses an analysis method of the content, nitrogen content, free formaldehyde and strength of free furfuryl alcohol, which comprises the following steps: according to JB/T7526-1994 self-hardening furan resin for casting; the formaldehyde emission was measured according to acetylacetone spectrophotometry in the national standard GB 13197-91.
The foregoing is merely exemplary and illustrative of the present invention and various modifications, additions and substitutions may be made by those skilled in the art to the specific embodiments described without departing from the scope of the present invention as defined in the accompanying claims.
Claims (6)
1. A preparation method of furan resin with low nitrogen and low free furfuryl alcohol is characterized by comprising the following steps:
(1) adding solid formaldehyde and furfuryl alcohol into a reaction kettle, stirring and mixing, adjusting the pH value to 2.5-3 by using an organic acid catalyst, reacting at the temperature of 110-120 ℃, and keeping the temperature for 3 hours to obtain a polymer;
(2) cooling to 70 ℃, adjusting the pH value to 8.5 by using a sodium hydroxide solution, adding urea and a triethanolamine catalyst, stirring and mixing uniformly, heating to 85 ℃, and carrying out heat preservation reaction for 1 hour;
(3) adjusting the pH value to 7-7.5 by formic acid, adding an aldehyde removing agent and a coupling agent, stirring and mixing uniformly, and discharging to obtain the product, namely the low-nitrogen low-free furfuryl alcohol furan resin.
2. The method for preparing furan resin with low nitrogen and low free furfuryl alcohol of claim 1, wherein the organic acid catalyst is mixed water solution of formic acid, propionic acid and maleic anhydride.
3. The method according to claim 1, wherein said sodium hydroxide solution is present at a concentration of 30 wt%.
4. The method for preparing furan resin with low nitrogen and low free furfuryl alcohol as claimed in claim 1, wherein the weight portions of the raw materials in each reaction stage are as follows: 8-12 parts of solid formaldehyde, 75-85 parts of furfuryl alcohol, 7-13 parts of urea, 0.5 part of triethanolamine, 1 part of aldehyde removing agent and 0.6 part of coupling agent.
5. The method according to claim 1, wherein said solid formaldehyde is paraformaldehyde with low degree of polymerization, and the content of paraformaldehyde is 92-96 wt%.
6. The method for preparing furan resin with low nitrogen and low free furfuryl alcohol as claimed in claim 1, wherein the coupling agent is N- (β -aminoethyl) - γ -aminopropylmethyldimethoxysilane.
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| CN201911187571.XA CN110862500A (en) | 2019-11-28 | 2019-11-28 | Preparation method of furan resin with low nitrogen and low free furfuryl alcohol |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112759733A (en) * | 2020-12-24 | 2021-05-07 | 天津宁康科技有限公司 | Preparation method of low-odor high-strength environment-friendly furan resin |
| CN114920895A (en) * | 2022-06-23 | 2022-08-19 | 山东永创材料科技有限公司 | Preparation method of cold-resistant furan resin |
| CN115125020A (en) * | 2022-06-23 | 2022-09-30 | 南京林业大学 | Method for directionally preparing nitrogen functional group semi-coke by using urea resin adhesive and biomass pyrolysis product model compound as raw materials |
-
2019
- 2019-11-28 CN CN201911187571.XA patent/CN110862500A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112759733A (en) * | 2020-12-24 | 2021-05-07 | 天津宁康科技有限公司 | Preparation method of low-odor high-strength environment-friendly furan resin |
| CN114920895A (en) * | 2022-06-23 | 2022-08-19 | 山东永创材料科技有限公司 | Preparation method of cold-resistant furan resin |
| CN115125020A (en) * | 2022-06-23 | 2022-09-30 | 南京林业大学 | Method for directionally preparing nitrogen functional group semi-coke by using urea resin adhesive and biomass pyrolysis product model compound as raw materials |
| CN114920895B (en) * | 2022-06-23 | 2023-09-29 | 山东永创材料科技有限公司 | Preparation method of cold-resistant furan resin |
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Application publication date: 20200306 |