JPS5881541A - Mold coating material for furan resin mold - Google Patents

Abstract

PURPOSE:To prevent the deterioration in the casting surfaces of moldings by coatong mold coating materials contg. monosaccharides, disaccharides and their esters on furan resin molds. CONSTITUTION:Grape sugar, cane sugar and cane sugar fatty acid esters are added to mold coating materials of graphite, zircon and lime, and such materials are coated on furan molds. When graphite cast iron is cast by using such molds, the formation of abnormal structure in the casting surfaces is prevented. The mold coating materials of lime are best for preventing the abnormal structure and if saccharides are added to the material, the abnormal structure is prevented thoroughly.

Description

DETAILED DESCRIPTION OF THE INVENTION Flange resin molds are widely used today because of their high molding rate and high regeneration rate of old sand.

However, this mold also has flaws. That is, when para-toluenesulfonic acid (PTS) used as a curing catalyst for frifuryl alcohol (FA) is decomposed by the heat of the molten metal, S diffuses into the casting surface and deteriorates the material. In particular, in the case of compact vermicular and spheroidal graphite cast iron, the effectiveness of the treatment agent is weakened due to the diffusion of S, and the graphite on the casting surface becomes flaky.

Therefore, cast products that are used without processing deteriorate in strength, corrosion resistance, and heat resistance, which poses a problem. For this reason,
Various mold coating agents have been developed so far. That is, magnesia-based fluids and lime-based products are in practical use, but
A paint that can completely prevent the diffusion of S has not yet been developed.

The present invention has been made in view of such circumstances.

Namely, S produced by the decomposition of para-toluenesulfonic acid
This invention relates to a mold paint in which a compound such as SOx is changed into a compound that does not diffuse into cast iron or steel.

NH3 is a substance that easily reacts with SOx. However, NH3
Since these compounds easily decompose at low temperatures, they are easily dissipated when they are mixed into a mold paint and dried after application. Therefore,
A substance that produces NH3 at high temperatures is required.

NH3 is produced today by the Haber process, but Mg3N
NH4 is also produced when water or steam is added to 2, AIN, t, - and CaCN2. However, these methods are difficult to apply to mold paints.

In the present invention, we focused on the fact that when monosaccharides, disaccharides, and their esters are decomposed at high temperatures, the activated hydrogen part reacts with nitrogen in the air to create NH3, and we use these saccharides as mold paint. Mix the SOx with ammonium sulfate (NH4)2S
This is an attempt to make it Ot.

Next, examples will be described.

Glucose, sucrose, and sucrose fatty acid esters (hereinafter referred to as SE) were added to the paint at 1 wt, %, and 2.5 wt, respectively.

%, 5 wt, % was added, and this was applied to the flan mold.
The table below shows the changes in the graphite structure on the casting surface when spheroidal graphite cast iron is cast.

□ 3 □ As described above, it has been found that adding sugars to graphite-based, zircon-based, and lime-based mold paints prevents the formation of abnormal structures on the casting surface of spheroidal graphite cast iron.

In the graphite-based material without additives, 2.8 abnormal structures were generated. If 1 wt.% of glucose was added to this, it would be 1.5%,
2.5 wt, % added is 0.5 mm, 5
The weight of wt.% added was 2 mm. When 1 wt% sucrose was added, the abnormal tissue size was 18 mm and 2
．． 5 wt, % added is 0.7 mm, 5 wt
,% added was 0.5m'In. SE to 1
The abnormal tissue was 1.6 mm when wt.% was added.
2.5 wt, % added is 0.3 wt, 5 wt
,% added, the allophonic tissue disappeared.

In the case of no zircon-based additive, 2.5 abnormal tissues were formed. Add 2.0% glucose to this. ! 5 wt,% addition is 0.4 mm1. ．． The one with 5 wt,% added is Q,
It became 2mm. 0.6 mm with 2.5 wt% sucrose added.

When 5wt% was added, the amount was 0,271Im. S
'The one with 2.5wt% of E added is 0.2mm, 5
Abnormal tissue disappeared in the case where % vat was added.

In the case of no lime-based additives, 0.6 abnormal tissues were generated. When glucose, sucrose, and 5Et-2.5wt% or more were added to this, the abnormal tissue disappeared.

The above results revealed that lime-based mold paints are the best for preventing abnormal tissues, and that adding 2.5 wt.% of sugars to these paints can completely prevent abnormal tissues. Similar results were obtained when compact vermicular graphite cast iron was tested.

The reason why lime-based mold paint has an excellent ability to prevent abnormal tissue is thought to be that CaO adsorbs S. Also, sugars decompose at high temperatures and react with nitrogen in the air to create NHa, which reacts with SOx to form ammonium sulfate...(NH4)2
The mechanism that creates S04 is currently under investigation.

In any case, it is clear that saccharides prevent S from penetrating into the casting surface.

As described above, we believe that the furan resin mold coating of the present invention will greatly contribute to this field.

Patent applicant Shin Chobei Yamaguchi)Q

Claims (1)

[Claims] A mold coating agent for furan resin molds, which is characterized in that a mold paint containing monosaccharides, disaccharides, and their esters is applied to furan resin molds to prevent deterioration of the casting surface of castings.