JPS62168636A - Coating material for mandrel of casting mold - Google Patents

Abstract

PURPOSE:To improve a release characteristic by incorporating a compd. which prohibits the oxidation of an acid curing resin for a casting mold into a coating material for the mandrel of the casting mold. CONSTITUTION:The compd. which prohibits the curing of the acid curing resin for the casting mold which is 1 or >=2 kinds selected from a polyhydric alcohol, long chain alcohol, amine, amide, imide, and alkaline compd. is incorporated into the coating material for the mandrel of the casting mold. The release characteristic of the mandrel is thereby improved and the need for cleaning the mandrel in the stage of cleaning a metallic mold is eliminated. The cleaning operations are thus decreased.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a coating agent for mold mandrels.

[Conventional technology]

Various types of mold release agents are known, but they are required to have both good mold release properties and not inhibit the hardening of foundry sand. That is, if the molding sand in contact with the mold is not hardened by the mold release agent, it loses its value as a mold. Conventionally, mold release agents for molds have also been used for mandrels.

[Problem that the invention seeks to solve]

Like molds, mandrels also require mold releasability.
When a large number of molds are manufactured continuously, if the mold releasability is poor, the number of cleaning increases, resulting in a decrease in manufacturing efficiency. If the mold releasability of the mandrel is better than the mold releasability of the mold, it becomes possible to omit cleaning the mandrel when cleaning the mold, so that the amount of cleaning work can be reduced. However, conventionally,
Coating agents (mold release agents) for mandrels have not been studied much.

[Means for solving problems]

The present inventors focused on the fact that it is not necessary to consider the mold and the mandrel on the same level, and that even if the molding sand in contact with the mandrel becomes slightly unhardened, it does not directly affect the quality of the casting. The present invention was completed based on the discovery that mold releasability can be greatly increased by coating a mandrel with a compound that inhibits the curing of acid-curable resins.

That is, the present invention provides a coating agent for a mold mandrel, which is characterized by containing a compound that inhibits the curing of an acid-curable resin for molds.

In the present invention, examples of the compound that inhibits curing of the acid-curable resin for molds include one or more selected from polyhydric alcohols, long-chain alcohols, amines, amides, imides, alkaline compounds, and the like.

Specific examples of these compounds are shown below.

(Al Polyhydric alcohols, ethylene glycol, alkylene glycols such as propylene glycol, polyalkylene glycols, glycerin, pentaerythritol, trimethylolpropane, sorbitol, sugars, etc.

long chain alcohol, aliphatic alcohol with 4 to 24 carbon atoms or its alkylene oxide adduct, alkylphenol having an alkyl group with 4 to 24 carbon atoms or its alkylene oxide adduct (C1 amine, amide or imide, monoethanolamine) From relatively small molecular weight substances such as , jetanolamine, triethanolamine, formamide, and dimethylformamide, to oleylamine,
laurylamine, stearylamine, oleylamide,
stearylamide, octylaminopropyleneamine,
Up to those with large molecular weights such as oleylaminopropylene amine, or their alkylene oxide adducts, etc.
Aromatic amines such as aniline, piperazine, pyridine, morpholine, etc.+d+ Alkaline compounds, calcium hydroxide, sodium hydroxide, potassium hydroxide, sodium phosphate, sodium carbonate, fatty acid soaps having 4 to 24 carbon atoms. , simply apply these compounds to the surface of the mandrel.

By applying these compounds to the surface of the mandrel, mold releasability (number of consecutive molds) is significantly increased.

The coating amount of the coating agent of the present invention is 1 to 100 m as an effective amount.
g/- is preferable. Further, the viscosity of the coating agent may be 10 cP or more, and may be as large as possible for coating.

If it is viscous or solid, it is used by dissolving or dispersing it in water or a solvent.

In addition to the above-mentioned essential ingredients, the coating agent of the present invention contains a rust preventive agent,
Thickeners, solvents (water-soluble, water-insoluble), solubilizers (dispersants), synthetic resins, etc. can be used in combination in arbitrary proportions.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 9 and Comparative Examples 1 to 3 A hollow mold manufacturing mandrel was coated with the coating agent according to the present invention shown in Table 1 for each mold molding (Examples 1 to 9), and a mandrel was coated with no coating agent (Examples 1 to 9). Comparative Example 1) or one coated with a known mold release agent shown in Table 1 for each mold molding (Comparative Example 2.3) was used in combination with a mold manufacturing model, furan resin was used as a binder, and organic sulfonic acid was used as a binder. A mixture obtained by adding and kneading 15 parts by weight of a binder and 6 parts by weight of a hardening agent to 1000 parts by weight of silica sand using an organic self-hardening method using as a hardening agent was mixed at an air pressure of 3 kg/c.
The limit number at which mold release would fail was observed by repeatedly molding by blowing at m''G.

The results are shown in Table 1.

Examples 10 to 15 and Comparative Examples 4 to 7 Using a mandrel coated with the coating agent shown in Table 2, using gaseous or aerosol sulfur dioxide as a curing gas, silica sand 10
00 parts by weight, 15 parts by weight of furan resin as a binder, and 6 parts by weight of methyl ethyl ketone peroxide as a catalyst were added and kneaded, and a mold was manufactured by the gas curing method. , the critical number at which mold release would occur was observed.

The results are shown in Table 2.

Claims (1)

[Scope of Claims] 1. A coating agent for mold mandrels, which contains a compound that inhibits curing of acid-curable resin for molds. 2. Claim 1, wherein the compound that inhibits the curing of the acid-curing resin for molds is one or more selected from polyhydric alcohols, long-chain alcohols, amines, amides, imides, and alkaline compounds. Coating agent as described.