CN-122007328-A - Self-hardening furan resin sand mold and preparation method thereof

CN122007328ACN 122007328 ACN122007328 ACN 122007328ACN-122007328-A

Abstract

The invention discloses an improved self-hardening furan resin sand mold and a preparation method thereof, and belongs to the technical field of casting molding materials. The method comprises the steps of introducing surfactant sodium dodecyl sulfate into a furan resin curing agent preparation process, wherein the curing agent consists of benzenesulfonic acid substances, concentrated sulfuric acid, alcohol water solution and sodium dodecyl sulfate, preparing a modified curing agent through pre-mixing and reacting, sequentially mixing silica sand, the modified curing agent and furan resin, and obtaining a sand mold through molding hardening. The invention improves the dispersibility and the permeability of the curing agent on the surface of sand grains through the sodium dodecyl sulfate, ensures uniform acidity distribution, obviously improves the room-temperature tensile strength of the sand mold, and reduces the sand inclusion defect rate of castings. The used surfactant is environment-friendly, has simple process, does not need complex equipment, and has important industrial application value.

Inventors

ZHAO JIANGUO
LIU RUIBING
GUO PEILIANG
GUO SHUCHEN
LI HONGXIA

Assignees

包头市一禾稀土铝业科技材料有限公司
宁夏一禾铝业科技新材料有限公司
山西一禾铝业科技新材料有限公司
宁夏鑫旺铝业有限公司
新疆一禾铝业科技新材料有限公司

Dates

Publication Date: 20260512
Application Date: 20260127

Claims (10)

1. The self-hardening furan resin sand mold is characterized by being prepared from the following raw materials, by weight, 97-99 parts of silica sand, 0.05-0.2 part of p-toluenesulfonic acid, 0.1-0.3 part of concentrated sulfuric acid, 0.1-0.3 part of an alcohol solution, 0.005-0.05 part of sodium dodecyl sulfate and 0.5-2 parts of furan resin.
2. The self-hardening furan resin sand mold of claim 1, which is characterized by being prepared from the following raw materials, by weight, 98 parts of silica sand, 1.4 parts of furan resin, 0.15 part of p-toluenesulfonic acid, 0.23 part of concentrated sulfuric acid, 0.2 part of glycol aqueous solution and 0.025 part of sodium dodecyl sulfate.
3. The self-hardening furan resin sand mold of claim 1, which is characterized by being prepared from the following raw materials, by weight, 98.5 parts of silica sand, 0.99 part of furan resin, 0.1 part of p-toluenesulfonic acid, 0.21 part of concentrated sulfuric acid, 0.19 part of glycol aqueous solution and 0.025 part of sodium dodecyl sulfate.
4. The self-hardening furan resin sand mold of claim 1, which is characterized by being prepared from the following raw materials, by weight, 98.9 parts of silica sand, 0.7 part of furan resin, 0.09 part of p-toluenesulfonic acid, 0.19 part of concentrated sulfuric acid, 0.17 part of glycol aqueous solution and 0.025 part of sodium dodecyl sulfate.
5. The self-hardening furan resin sand mold of claim 1, wherein the mass concentration of the concentrated sulfuric acid is more than or equal to 98wt%, and the alcohol solution is prepared from ethylene glycol and water according to a volume ratio of 1:1.
6. The self-hardening furan resin sand mold according to claim 1, wherein the silica sand has a SiO 2 mass content of 92.0wt%, a mud content of <1wt%, a water content of <0.3wt%, a particle size of 30-70 meshes, a furan resin density of 1.0-1.3 g/mL, a viscosity of 30-40 mPa.s, and a water content of <11wt%.
7. A method for preparing the improved self-hardening furan resin sand mold according to any one of claims 1 to 6, which is characterized by comprising the following steps: (1) The raw materials comprise, by weight, 97-99 parts of silica sand, 0.05-0.2 part of p-toluenesulfonic acid, 0.1-0.3 part of concentrated sulfuric acid, 0.1-0.3 part of alcohol solution, 0.005-0.05 part of sodium dodecyl sulfate and 0.5-2 parts of furan resin, and the raw materials are respectively weighed according to the composition; (2) The preparation of the curing agent comprises the steps of mixing p-toluenesulfonic acid, sodium dodecyl sulfate and an alcohol solution, stirring and dissolving uniformly, adding concentrated sulfuric acid, stirring and reacting for 50-70 min at the temperature of 30-50 ℃, and cooling to room temperature to obtain the modified curing agent; (3) Mixing, namely mixing silica sand with the modified curing agent to uniformly cover the surface of sand grains by the curing agent, and adding furan resin to uniformly mix to obtain a molding sand mixture; (4) And (3) molding and hardening, namely filling the molding sand mixture into a mold, performing self-hardening molding at room temperature, and demolding to obtain the furan resin sand mold.
8. The preparation method of claim 7, wherein the mixing in the step (3) is performed at an ambient temperature of 0-40 ℃ and a relative humidity of 40-70%.
9. The preparation method of claim 7, wherein the mixing time of the curing agent and silica sand in the step (3) is 1-5 min, and the furan resin is added for continuous mixing for 1-5 min.
10. The method according to claim 7, wherein in the step (4), the mixed molding sand mixture is filled into a mold in 10 min, self-hardening is performed at room temperature, and the mold is released after 20: 20 min.

Description

Self-hardening furan resin sand mold and preparation method thereof Technical Field The invention relates to the technical field of casting molding materials, in particular to a self-hardening furan resin sand mold and a preparation method thereof. Background Furan resins are one of the most widely used organic binders in sand casting, particularly in the cast iron and aluminum industries. The self-hardening mortar can be self-hardened at room temperature after being mixed with a matched curing agent, and has the advantages of high production efficiency, good molding sand performance and the like. The performance of the curing agent is a key factor in determining the final performance of the self-hardening furan resin sand. The curing agents commonly used at present comprise sulfonic acids (such as benzenesulfonic acid and p-toluenesulfonic acid), phosphoric acids, sulfuric acid esters and the like. In order to reduce the sulfur content and improve the performance, modified sulfonic acid curing agents are generally mixed by inorganic acid (such as concentrated sulfuric acid), alcohol substances (such as ethylene glycol) and benzenesulfonic acid substances in the prior art. However, such modified curatives still suffer from poor dispersibility and permeability during application. This results in uneven distribution of the curing agent across the sand surface, such that there is a difference in acidity from sand surface to sand surface. Acidity not only directly affects the curing strength of furan resins, but also is closely related to the curing rate. Uneven acidity distribution can cause local solidification to be too fast or too slow, residual stress to be generated inside the sand mold, weakening the integrity of the resin bond film between sand grains, and eventually resulting in a decrease in the overall strength of the sand mold. The sand mould with insufficient strength is easy to have the problems of surface sand falling, sand washing and the like in the process of carrying and pouring, so that the defects of sand inclusion, sand holes and the like of the casting are caused. In order to improve the dispersibility of the curing agent, various surfactants such as alkylphenol ethoxylates, sodium dodecylbenzenesulfonate, fatty alcohol ethoxylates, and the like have been attempted in the prior art. However, alkylphenol ethoxylates and sodium dodecyl benzene sulfonate have the problems of poor biodegradability, unfriendly environment and the like. While the fatty alcohol-polyoxyethylene ether is improved in terms of environmental protection, the fatty alcohol-polyoxyethylene ether has limited capability of reducing the surface tension (about 33.46 mN/m) and the contact angle (about 32.3 DEG) of the liquid, and has no ideal effect of improving the dispersibility and the permeability of the curing agent. In contrast, sodium dodecyl sulfate has lower surface tension (about 29.64 mN/m) and contact angle (about 16.7 °), theoretically has better wetting, dispersing and penetrating properties, is more friendly to the environment, but is rarely applied to self-hardening furan resin curing agent systems at present. Therefore, the development of the preparation method which can remarkably improve the dispersion and permeability of the curing agent and further improve the strength of the sand mold and is environment-friendly has important significance. Disclosure of Invention The invention aims to overcome the defects of insufficient strength and easy casting defects caused by uneven dispersion of a curing agent of the existing self-hardening furan resin sand mould, and provides an improved self-hardening furan resin sand mould capable of remarkably improving the room temperature strength of the sand mould and reducing the casting defects and a preparation method thereof. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The sand mold for improving self-hardening furan resin is prepared from the following raw materials, by weight, 97-99 parts of silica sand, 0.05-0.2 part of p-toluenesulfonic acid, 0.1-0.3 part of concentrated sulfuric acid, 0.1-0.3 part of an alcohol solution, 0.005-0.05 part of sodium dodecyl sulfate and 0.5-2 parts of furan resin. The self-hardening furan resin sand mold is prepared from the following raw materials, by weight, 98 parts of silica sand, 1.4 parts of furan resin, 0.15 part of p-toluenesulfonic acid, 0.23 part of concentrated sulfuric acid, 0.2 part of glycol aqueous solution and 0.025 part of sodium dodecyl sulfate. The self-hardening furan resin sand mold is prepared from the following raw materials, by weight, 98.5 parts of silica sand, 0.99 part of furan resin, 0.1 part of p-toluenesulfonic acid, 0.21 part of concentrated sulfuric acid, 0.19 part of glycol aqueous solution and 0.025 part of sodium dodecyl sulfate. The self-hardening furan resin sand mold is prepared from the following raw materials, by weight, 98.9 parts of silica