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CN-117320823-B - Method for producing binder resin for casting mold

CN117320823BCN 117320823 BCN117320823 BCN 117320823BCN-117320823-B

Abstract

The present invention provides a method for producing a binder resin for mold molding, which comprises a step A of reacting a furanmethanol with formaldehyde in the presence of 1 or more catalysts a selected from phosphoric acid and boric acid and 1 or more neutralization salts a selected from a neutralization salt of phosphoric acid and boric acid, wherein in the step A, the amount of the catalyst a is 0.0002 mol or more and 0.01 mol or less relative to 1 mol of furanmethanol, and the amount of the neutralization salt a is 0.003 mol or more in terms of acid relative to 1 mol of furanmethanol. According to the present invention, there can be provided a method for producing a binder resin for mold molding, which has a high reaction rate, a small content of monomeric furanmethanol, a large content of dimethylolfuran, and a low viscosity.

Inventors

  • MATSUO TOSHIKI
  • TANAKA DAIKI
  • YAMAGUCHI DAISUKE

Assignees

  • 花王株式会社

Dates

Publication Date
20260508
Application Date
20210531

Claims (20)

  1. 1. A process for producing a binder resin for mold molding, which comprises preparing a binder resin for mold molding comprising furanmethanol, dimethylolfuran and a furan resin, The production method comprises a step A of reacting furanmethanol with formaldehyde in the presence of a catalyst a selected from 1 or more of phosphoric acid and boric acid and a neutralizing salt a selected from 1 or more of a neutralizing salt of phosphoric acid and boric acid, In the step A, the amount of the catalyst a is 0.0002 mol or more and 0.01 mol or less per 1 mol of furanmethanol, the amount of the neutralization salt a is 0.003 mol or more and 0.15 mol or less in terms of acid per 1 mol of furanmethanol, The neutralization salt a is more than 1 selected from alkali metal salts and amine salts.
  2. 2. The method according to claim 1, wherein the pH of the reaction solution before the start of the reaction in the step A is 2 or more and 5.5 or less.
  3. 3. The production method according to claim 1 or 2, wherein the neutralization salt a is an amine salt, and the amine salt is a tertiary amine salt having an alkyl group having 2 to 10 carbon atoms.
  4. 4. The production method according to claim 1 or 2, wherein the content of furanmethanol in the binder resin for mold formation is 30 mass% or less.
  5. 5. The production method according to claim 1 or 2, wherein the content of dimethylolfuran in the binder resin for mold formation is 8 mass% or more.
  6. 6. The production method according to claim 1 or 2, wherein the content of furanmethanol in the binder resin for mold formation is 10 mass% or more.
  7. 7. The production method according to claim 1 or 2, wherein the content of dimethylolfuran in the binder resin for mold formation is 40 mass% or less.
  8. 8. The production method according to claim 1 or 2, wherein the content of the furan resin in the binder resin for mold formation is 30 mass% or more and 60 mass% or less.
  9. 9. The process according to claim 1 or 2, wherein the furan resin is at least 1 selected from the group consisting of urea-modified furan resins, condensates of furanmethanols and aldehydes, and co-condensates of at least 2 selected from the group consisting of urea-modified furan resins and condensates of furanmethanols and aldehydes.
  10. 10. The production method according to claim 1 or 2, wherein the degree of neutralization of the catalyst a, that is, the neutralization salt a/(catalyst a+neutralization salt a), is 25% or more and less than 100%.
  11. 11. The method according to claim 1 or 2, wherein the method comprises producing a binder resin for mold molding comprising furanmethanol, dimethylolfuran and a furan resin, The production method comprises a step A of reacting furanmethanol with formaldehyde in the presence of a catalyst a selected from 1 or more of phosphoric acid and boric acid and a neutralizing salt a selected from 1 or more of a neutralizing salt of phosphoric acid and boric acid, In the step A, the amount of the catalyst a is 0.0004 mol or more and 0.008 mol or less per 1mol of furanmethanol, the amount of the neutralization salt a is 0.005 mol or more and 0.04 mol or less in terms of acid per 1mol of furanmethanol, The neutralization salt a is more than 1 selected from alkali metal salts and amine salts, The furan resin is1 or more selected from the group consisting of urea-modified furan resins, condensates of furanmethanols and aldehydes, and co-condensates of 2 or more selected from the group consisting of urea-modified furan resins and condensates of furanmethanols and aldehydes.
  12. 12. The method according to claim 1 or 2, wherein the method comprises producing a binder resin for mold molding comprising furanmethanol, dimethylolfuran and a furan resin, The production method comprises a step A of reacting furanmethanol with formaldehyde in the presence of a catalyst a selected from 1 or more of phosphoric acid and boric acid and a neutralizing salt a selected from 1 or more of a neutralizing salt of phosphoric acid and boric acid, In the step A, the amount of the catalyst a is 0.0004 mol or more and 0.008 mol or less per 1mol of furanmethanol, the amount of the neutralization salt a is 0.005 mol or more and 0.04 mol or less in terms of acid per 1mol of furanmethanol, The neutralization degree of the catalyst a, that is, the amount of the neutralizing salt a/(the amount of the catalyst a+the amount of the neutralizing salt a) is 93% to 97%, The neutralization salt a is more than 1 selected from alkali metal salts and amine salts, The furan resin is at least 1 selected from urea-modified furan resins, condensates of furanmethanols and aldehydes, and co-condensates of at least 2 selected from urea-modified furan resins and condensates of furanmethanols and aldehydes.
  13. 13. The production method according to claim 1 or 2, wherein the content of furanmethanol in the binder resin for mold formation is 10 mass% or more and 30 mass% or less, the content of dimethylolfuran is 8 mass% or more and 40 mass% or less, and the content of furan resin is 30 mass% or more and 60 mass% or less.
  14. 14. A binder composition for molding comprising a furanmethanol component A, a dimethylolfuran component B, a furan resin component C, and a water component D The following conditions (1) - (4) are satisfied: The condition (1) is that the content of the component A in the binder composition for casting mold is more than 0 mass% and less than 30 mass%; the condition (2) is that the content of the component B in the binder composition for casting mold is 7 mass% or more and 30 mass% or less; The condition (3) is that the content of the component D in the binder composition for casting mold is more than 0 mass% and less than 25 mass%; In the binder composition for mold molding of 100 g, the content of the catalyst a selected from the group consisting of phosphoric acid and boric acid is 0.01 to g and 0.50 to g, and the content of the neutralization salt a selected from the group consisting of phosphoric acid and boric acid, which is 1 or more selected from the group consisting of alkali metal salts and amine salts, is 0.13 to g and 15 to g, in terms of acid.
  15. 15. The binder composition for mold shaping according to claim 14, wherein the furan resin comprises at least 1 kind selected from the group consisting of urea-modified furan resins, condensates of furanmethanols and aldehydes, and co-condensates of at least 2 kinds selected from the group consisting of urea-modified furan resins and condensates of furanmethanols and aldehydes.
  16. 16. The binder composition for mold shaping according to claim 14 or 15, wherein a total amount of the catalyst a content and the acid-converted content of the neutralization salt a in the binder composition for mold shaping of 100g is 0.2 to g and 15 to g.
  17. 17. The binder composition for mold shaping according to claim 14 or 15, wherein a ratio of the content of the component C to the content of the component B in the binder composition for mold shaping, i.e., the content of the component C/the content of the component B is 1 or more and 7 or less.
  18. 18. The binder composition for mold shaping according to claim 14 or 15, wherein the content of the component C in the binder composition for mold shaping is 25 mass% or more and 50 mass% or less.
  19. 19. The binder composition for mold shaping according to claim 14 or 15, wherein the content of the component D in the binder composition for mold shaping is 5 mass% or more.
  20. 20. The binder composition for mold shaping according to claim 14 or 15, wherein a ratio of the content of the neutralized salt a in terms of acid to a total amount of the content of the catalyst a and the content of the neutralized salt a in terms of acid, that is, a content of the neutralized salt a in terms of acid/(a content of the catalyst a+a content of the neutralized salt a in terms of acid) is 0.25 or more and less than 1.

Description

Method for producing binder resin for casting mold Technical Field The present invention relates to a method for producing a binder resin for mold molding. Background In general, an acid-curable mold is produced by adding a binder composition for mold molding containing an acid-curable resin and a curing agent composition containing sulfonic acid, sulfuric acid, phosphoric acid, or the like to refractory particles such as silica sand, kneading the above, filling the obtained kneaded sand into a master such as a wood pattern, and curing the acid-curable resin. The acid-curable resin may be a furan resin, a phenol resin, or the like, and the furan resin may be a furanmethanol-urea-formaldehyde resin, a furanmethanol-phenol-formaldehyde resin, another known modified furan resin, or the like. Such a method for producing a mold can realize a molding operation with a high degree of freedom, and is widely used for casting a machine part, a construction machine part, an automobile part, or the like because the mold is excellent in thermal properties and can produce a high-quality casting. In terms of producing a mold, as one of important conditions, improvement of the working environment at the time of producing a mold (at the time of curing a resin) is mentioned, and in particular, reduction of the monomer-like furanmethanol in a furanic resin is desired in order to reduce the furanic alcohol volatilized at the time of producing a mold. For example, JP-A2014-501175 discloses that the use of a binder composition having a small content of monomeric furanmethanol can reduce the release of furanmethanol and formaldehyde during kneading and molding. In addition, japanese patent application laid-open No. 56-61420 discloses a method for producing a phenol-furanmethanol-formaldehyde resin for mold molding, which comprises introducing a furanmethanol skeleton into a resin structure at a high ratio by sufficiently carrying out a reaction, wherein the content of the furanmethanol is small in the monomer form. In addition, japanese patent application laid-open No. 2013-151019 discloses that by using a binder composition containing 5-hydroxymethylfurfural and 2, 5-dimethylolfuran instead of furanmethanol, mold release time can be shortened under the same service life, thereby improving mold productivity and curing speed and mold strength. Disclosure of Invention The present invention provides a method for producing a binder resin for mold shaping, which comprises a step A of reacting a furanmethanol with formaldehyde in the presence of a catalyst a selected from 1 or more of phosphoric acid and boric acid and a neutralizing salt a selected from 1 or more of a neutralizing salt of phosphoric acid and boric acid, wherein in the step A, the amount of the catalyst a is 0.0002 mol or more and 0.01mol or less relative to 1mol of furanmethanol, and the amount of the neutralizing salt a is 0.003 mol or more in terms of acid relative to 1mol of furanmethanol. The present invention also provides a binder composition for mold molding, which contains furanmethanol (component a), dimethylolfuran (component B), furan resin (component C) and water (component D), and satisfies the following conditions (1) to (4). The condition (1) is that the content of the component A in the adhesive composition for casting mold is below 30 mass%; The condition (2) is that the content of the component B in the binder composition for casting mold is 7% by mass or more; the condition (3) is that the content of the component D in the binder composition for casting mold is 25 mass% or less; In the binder composition for mold molding, the content of the catalyst a is 0.01g or more and 0.50g or less in 100g or more selected from phosphoric acid and boric acid, and the content of the neutralization salt a is 0.13g or more in terms of acid in one neutralization salt selected from phosphoric acid and boric acid. The present invention also provides a molding composition comprising the above binder composition for molding and a curing agent composition comprising a curing agent for curing the binder composition for molding. The present invention also provides a molding composition containing refractory particles, the binder composition for molding, and a curing agent composition containing a curing agent for curing the binder composition for molding. The present invention also provides a method for producing a mold, comprising a mixing step of mixing refractory particles, the binder composition for mold molding, and a curing agent composition containing a curing agent for curing the binder composition for mold molding to obtain a composition for mold, and a curing step of filling the composition for mold into a mold frame and curing the composition for mold. Detailed Description There is room for improvement in the adhesive compositions having a low content of the monomeric furanmethanols proposed in the past, which have insufficient mold strength. In addition, it is a