JPS59142295A - Stainproofing agent for cold box process - Google Patents

Abstract

PURPOSE:To provide a stainproofing agent containing a specified phosphonic acid or salt thereof as essential ingredient and preventing staining when used together with a known release agent. CONSTITUTION:The stainproofing agent for cold box process contains phosphonic acid of the formula [where Rf is perfluoroalkenyl; Ar is (substituted) aromatic group; l is 1-3; n is 1 or 2; M and M' are residues of a salt (e.g. Mg, Zn or triethanolamine)] or salt thereof as essential ingredient. For example, conventional release agents such as those based on silicon, wax or resin tend to cause staining of molding sand due to blowing when used in a cold box process. The stainproofing agent prevents staining when used in combination with these release agents. Among the phosphonic acid and salt thereof, partly neutralized salt gives best results.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-stain agent used in the cold box method.

The cold box method is, for example, as shown in Figure 1, in which molding sand (2) mixed with phenol resin and polyisocyanate is filled into the pattern (1) of a cold box mold using a blowing machine or shooter, and amine gas is applied to the molding sand (2). This is a method of hardening and molding the foundry sand by aerating a catalyst gas (3) containing . In this case, a mold (made of iron or aluminum) is often used as the material for the pattern (1).

However, if conventional mold release agents commonly used in the cold box method, such as silicone-based, wax-based, or resin-based mold release agents, are used, molding sand tends to bleed due to blowing, and mold release agents tend to bleed through. The durability of the mold is not satisfactory.

The present invention provides a cold hox stain prevention agent that improves the above-mentioned drawbacks, and has the general formula: % formula %) [wherein Rf is a perfluoroalkenyl group and Ar may have a substituent] An aromatic group, l is 1 to 3.

n is 1 or 2 and M and! represents hydrogen or a salt residue] or a salt thereof as an essential component.

Among the above-mentioned phosphonic acids or salts thereof, particularly good results are obtained with the partially neutralized salts thereof.

The perfluoroalkenyl residue of the perdyloalkanyloxyarylphosphonic acid derivative used in the present invention is derived from a polymer of tetrafluoroethylene or hexafluoropropene, and has 3 to 18 carbon atoms.
Preferably, hexafluoropropene dimer or trimer residues are preferred. Aromatic groups are phenyl,
Naphthyl and those having an alkyl group, aryl group, acyl group, alkoxy group, halogen, etc., especially phenyl group.

A particularly preferred compound is perfluorononenyloxybenzylphosphonate, especially its partially neutralized salt.

The salt residue represented by M or M is lithium, sodium,
Alkali metals such as potassium, alkaline earth metals such as magnesium, calcium, strontium, barium, etc., metals such as zirconium, zinc, lead, tin, copper, nickel, iron, aluminum, cadmium, chromium, ammonia, -
secondary, secondary, or tertiary long-chain or short-chain alkylamines, alkanolamines, aromatic amines such as aniline, heterocyclic amines such as pyridine, morpholine, piperidine, and polyvalent amines such as ethylenediamine. etc., and the amines may be alkylene oxide adducts. Particularly preferred salt residues are magnesium, zinc, zirconium (zirconyl salt), triethylamine, diisopropanolamine, dicyclohexylamine, and the like.

The degree of neutralization of phosphonic acids may be either unneutralized or partially neutralized, but it is particularly preferable to neutralize 1 mole of phosphonic acid with 0.7 to 1.3 equivalents of alkali. It is a harmonious one.

The fluorine-containing phosphonic acid derivative of the present invention can generally be synthesized by the following method. First, (1) a hexafluoropropene oligomer or a tetrafluoroethylene oligomer is reacted with an aromatic compound having at least one hydroxyl group to produce perfluoroalkenyl aryl ether. (2) When the -r'+j-lether is reacted with a monohalo or dihaloether, or when formaldehyde or a polymer thereof is reacted in the presence of hydrogen halide, or when the aryl ether has an alkyl substituent. produces perfluoroalkenylhaloalkylaryl ether by halogenating the alkyl group in the presence of a radical catalyst. (3) The obtained haloalkylarylnitate trialkyl sulfite is reacted with the sulfite trialkyl ester to obtain a dialkyl phosphonate derivative, which is hydrolyzed and optionally neutralized with an appropriate base to obtain the target compound.

When the anti-staining agent of the present invention is used in combination with conventionally known mold release agents, such as silicone mold release agents, wax mold release agents, resin mold release agents, and other fluorine mold release agents, these disadvantages may be avoided. It can prevent staining.

Combination with silicone mold release agents gives particularly favorable results. Preferred silicone mold release agents are liquid, semi-solid or solid in normal flow, with a boiling point of 100°C or higher and a melting point of 100°C.
The following polysiloxanes containing an alkyl group, fluoroalkyl group, phenyl Ts, etc. in the side chain are preferred,
Particularly preferred is dimethylpolysiloxane. Higher alcohols or higher fatty acid-modified silicone mold release agents may be used. Furthermore, silicone fleece and silicone oil, which are silicone mold release agents mixed with silica powder and carbon black, are also included in the silicone mold release agents referred to herein.

As a silicone mold release agent, the formula: A mold release agent containing a silicone compound represented by is preferred.

The compounding ratio of the perfluoroalkenyloxyaryl phosponic acid derivative and the silicone mold release agent is preferably 20:1 to 1:10, particularly 5:1 to 1:5 in terms of solid content weight.

The anti-stain agent of the present invention may include a surfactant, fluorinated oil, silica powder, polytetrafluoroethylene powder, fluorinated graphite powder, aluminum powder, filler such as polyvinyl alcohol-vinyl acetate resin, etc.-film formation. A viscosity modifier or a viscosity modifier may also be added. When water is used, a preservative or rust preventive agent may be added as necessary.

The anti-stain agent of the present invention is produced by using at least one or more phosphonic acids or salts thereof and dissolving or dispersing them in an organic solvent (including in the form of a grease).

Examples of organic solvents include alcohols such as methanol, ethanol, propatool, and isopropyl alcohol, ketones such as acetone, methyl ethyl ketone, and methyl imbutyl ketone, ethers such as ethyl ether, isopropyl ether, dioxane, and tetrahydrofuran, ethyl acetate, Esters such as butyl acetate, methyl cellosolve, ethyl cellosolve, methyl carbitol, polyhydric alcohol derivatives such as ethyl carbitol, carbon tetrachloride, methylene chloride, ethylene chloride, trichloroethylene, perchloroethylene, trichloroethane, trichlorofluoromethane, tetra Examples include 10-genated hydrocarbons such as chlorodifluoroethane and trichlorotrifluoroethane.

The concentration (non-volatile content) of the anti-stain agent of the present invention in the medium varies depending on its purpose of use, and if the purpose is only one-time mold release, usually 0.1 w/w% or less is sufficient; When long-term application is required, it is usually 0.・5-20 w/w%, preferably 1-10
w/w% is appropriate.

The anti-stain agent of the present invention may be applied to a mold by any known method, such as by dipping, spraying, brushing, etc., or by spraying it as an aerosol, or by soaking it into a cloth and applying it. It can be applied to a mold and the medium can be removed by evaporation.

The present invention will be explained below with reference to Examples.

In the examples, parts or % are expressed by weight unless otherwise specified.

Example 6 To 1000 parts of silica sand, 10 parts of a 60% solution of benzyl ether type phenolic resin (the solvent was a 3:2 mixture of aromatic hydrocarbon and cellosolve acetate) was added, mixed for 1 minute using a stirrer, and then added with diphenylmethane diisocyanate. 70 of
% solution (the solvent is an aromatic hydrocarbon) and mixed for 2 minutes to prepare kneaded sand for molds.

Next, a cast iron mold as shown in FIG. 2 for molding the AFS tensile test piece was prepared, and the inside surface of the mold was uniformly sprayed with a stain preventive agent as detailed below. Then, it was dried until the solvent was sufficiently volatilized.

The kneaded sand is blowing at a blowing pressure of 3.
OKy/cm'' into the cast iron mold (5) to form a tensile test piece.Next, a mixture of triethylamine and air was passed through the test piece for 2 seconds, and then only air was injected at 100 ml.
The specimen was cured by aeration for seconds. After spraying the anti-stain agent once, repeat this operation 10 times.
At that time, the kneading sand stuck to the mold was scraped off and its weight was measured.

On the other hand, the mold releasability (pulling load) is determined by the iron cylinder as shown in Figure 3 (
The top diameter is 28 mm, the bottom diameter is 30 mm, the height is 50 mm, the draft angle is 2150 mm, and is polished with sandpaper (extra-fine). After cleaning the surface with acetone, apply various anti-stain agents evenly. This was embedded together with kneaded sand in the center of a 50/×50 mm wooden frame for measuring resistive pressure, and then hardened by gutting. Evaluation is made by measuring the pull-out load at that time.

Using anti-stain agents having the formulations shown in Table 1, the anti-stain effect and pull-out load were measured. The results are also listed in Table-1.

In the evaluation, in order to speed up drying, a low-boiling point solvent and easily amine salt and Zn salt were used.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a mold used in the cold box method, Fig. 2 is a schematic diagram of a mold for making AFS tensile test pieces, and Fig. 3 is a diagram showing the shape of an iron cylinder for measuring mold releasability (pulling load). In the figure, (1) shows the pattern, (2) the molding sand, (3) the catalyst gas, (4) the blowing machine, and (5) the mold. Tank “Applicant NEOS Co., Ltd. Kobe Rikagaku Kogyo Co., Ltd.

Claims (1)

[Claims] 1. Formula: %Formula%) [In the formula, Rf is a perfluoroalkenyl group, Ar is an aromatic group that may have a substituent, e is 1 to 3, n is 1 or 2, and M and M represent hydrogen or salt residue]
A stain preventive agent for cold box method containing phosphonic acid or its salt as an essential ingredient. 2. The anti-stain agent according to item 1, wherein Ar is a phenyl group. 3. The stain preventive agent according to item 1, which is a perfluoroalkenyl group having 3 to 18 carbon atoms. 4. The compound of formula [■] is a partially neutralized salt of perfluorononenyloxybenzylphosphonic acid. 5. The stain preventive agent according to item 1, wherein either M or kidney is hydrogen. 6. Formula: % formula %) [In the formula, R (is perfluoro Alkenyl group, Ar is an aromatic group that may have a substituent, l is 1 to 3, n is 1
or 2 and M and d represent hydrogen or salt residues]; and a silicone mold release agent. 7. The silicone mold release agent has the formula: [In the formula, R, R, R, and R each independently represent an alkyl group, a fluoroalkyl group, or a phenyl group, and n is 1 to 3
The anti-stain agent according to item 6, which is represented by 8. R', R' in the silicone mold release agent of the formula [m. 8. The anti-stain agent according to item 7, wherein k is methyl.