JPS59153542A - Removing agent for deposit on mold - Google Patents

Abstract

PURPOSE:To provide an agent capable of removing easily deposit on the surface of a mold having complex structure using a solvent contg. a specified amt. of dimethyl sulphoxide and a specified amt. of surface active agent. CONSTITUTION:A remover of deposit on the mold is composed of a compsn. consisting of 0.01-10wt% surface active agent and >=60, pref. >=70wt% dimethyl sulphoxide. Preferred surface active agent is a fluorine-contg. surface active agent e.g. a derivative from dimer or trimer of hexafluoropropene, or a hydrocarbon type surface active agent, e.g. dialkyl sulphosuccinate.

Description

[Detailed description of the invention] The present invention relates to a mold deposit removal agent.

The metal mold used is a mixture of resin and sand, which is reacted and solidified. The reactant adheres to the mold for producing the reactant, and its removal has traditionally been time-consuming.

Conventionally, in order to solve this problem, physical methods such as hammer, brush, shot blasting, etc., or methods of dissolving and removing using an appropriate solvent have been adopted.

However, the physical method cannot be said to be the best method because it must be done manually for molds with complex structures, which requires labor and time, and is easily damaged. In the solvent method, removal usually takes one week or more, and removal is often incomplete, requiring further brushing or the like after treatment.

The present invention contains at least 60 tonne of dimethyl sulfoxide.
The present invention relates to a mold deposit removal agent containing 0.01 to 10% by market weight of a solvent and a surfactant.

The surfactant used in the present invention is preferably a fluorine-based surfactant, a hydrocarbon-based anionic surfactant, or a hydrocarbon-based nonionic surfactant, with fluorine-based surfactants and hydrocarbon-based anionic surfactants being particularly preferred. .

Examples of fluorosurfactants include alkali salts of perfluorocarboxylic acids and sulfonic acids, and sulfonic acid amide compounds; those having oligomers or polymers of tetrafluoroethylene and hexafluoropropene as hydrophobic groups, such as perfluoroalkenyl aryl ether derivatives, such as JP-A Publication No. 51-11084, British Patent No. 127066
Examples include those described in Specification No. 2, and reaction products of tetrafluoroethylene, hexafluoropropene, or oligomers thereof with polyhydric alcohols, especially polyalkylene glycols. All of these fluorine compounds are particularly preferred for the purpose of the present invention, but among them, those derived from dimers and trimers of hexafluoropropene include perfluorocarboxylic acids and sulfonic acids (which are less expensive than these). This is particularly preferred because it allows products to be produced that are more homogeneous than tetrafluoroethylene oligomers.

As the hydrocarbon water 3!8 thread nonionic surfactant], polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, etc. are preferable. Both have a relatively small number of added moles of ethylene oxide, for example 3 to 10
A compound having a molar level, that is, a compound having low hydrophilicity and low surface tension is suitable.

The hydrocarbon anionic surfactant is preferably a sulfonic acid type or a sulfuric acid ester type, and typically dialkyl sulfosuccinates, alkylbenzene sulfonates, and alkyl sulfate ester salts. Special (dioctyl sodium sulfosuccinate, dodecylbenzenesulfonic acid sodium,
Half soda salt of lauryl sulfate is preferred.

Two or more of these surfactants may be used in combination.

In the case of a fluorine-based surfactant, the amount used is 0.01 to 10% by weight of the total mold deposit removal agent, preferably 0.01 to 1.
0% by weight, in the case of hydrocarbon surfactants, 0.1-10
% of seams, preferably 1 to 5% by weight.

In the present invention, dimethyl sulfoxide is used as the organic solvent. Other organic solvents, such as N-methyl-2-pyrrolidone, show a deposit removal rate close to that of dimethyl sulfoxide when compared alone, but do not show such a significant improvement in removal rate when used in combination with a surfactant. . It is remarkable that the removal rate with dimethyl sulfoxide is significantly improved by surfactants.

However, dimethyl sulfoxide has a high melting point <(1
8'C), use in winter (this may cause some problems. In this case, other low melting point organic solvents, such as lN-methyl-2-pyrrolidone, γ-phthyllactone, carhitol, / Methyl-2-formamide, ethylene glycolne acetate, etc. may be used to lower the melting point of the removing agent.In this case, dimethyl sulfoxide must be used in an amount of 60 tons or more of the total solvent in order not to substantially reduce the removal rate. 1-1 preferably 70%, but not more than 1-1%.

According to the present invention, mold deposits with complex structures can be easily removed without causing damage compared to conventional physical methods, and in a shorter time (e.g., 2 days) compared to conventional solvent methods. Moreover, deposits can be removed to a satisfactory degree.

The present invention will be explained below with reference to Examples. In the examples, parts and percentages are expressed by weight unless otherwise specified.

Example: 100 parts of foundry sand (crushed sand: Hamaoka sand) was mixed with 1.0 parts of a resin (phenol resin (resol type)) and 10 parts of a hardening agent (polyisocyanate type), and a core hardened by the cold box method was made into a test piece. and measure the weight with foundry sand attached. Next, use the mold deposit removal agent shown in Table 1 (soak at room temperature for 48 hours. Raise the bow, dry it, and measure the amount to determine the removal rate. The results are shown in Table 1 (in the table,
A, B.

C and I) show comparative examples).

Claims (1)

[Scope of Claims] 1. A mold deposit removal agent containing a solvent containing at least 60% by weight of dimethyl sulfoxide and a surfactant in an amount of 0.001 to 10% by weight. 2. The removing agent according to item 1, wherein the surfactant is a fluorosurfactant. 3. The removing agent according to item 1, wherein the surfactant is a hydrocarbon thread anionic surfactant. 4. The removing agent according to item 3, wherein the hydrocarbon anionic surfactant is a sulfonate or a sulfuric acid ester salt, and contains 0.01 to 10% by weight.