JPS5933054A - Resin composition for light alloy molding sand and its production - Google Patents

Abstract

PURPOSE:To provide a titled compsn. which is curable at low temp. and can be molded to a casting mold having a good collapsing property after casting by adding a specific amt. of dicyandiamide to a phenolic resin. CONSTITUTION:A resin compsn. for light alloy having low temp. curing performance consists of 100pts.wt. a phenolic resin cong. 1-40pts.wt. dicyandiamide. Such compsn. is obtd. by adding and mxing dicyandiamide to and with a binder in a stage of dissolving or dispersing dicyandiamide into the binder or in a stage of coating the binder on the sand. Otherwise, dicyandiamide is beforehand added to the sand then the binder is mixed therewith or dicyandiamide is mixed with the sand incorporated beforehand with the binder.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a casting Sunagawa resin composition used for molding molds for one-piece molding, and has a high hardening property that can be used to mold molds with good disintegration properties after one-filling. The company will compete in the sixth round to provide a resin composition for light alloy and sand.

In mold making methods such as the Siermoji ruby method, which uses phenolic resin as the main binder, castings of metals such as aluminum and copper alloys, whose molten metal temperature is lower than that of cast iron, are made. In some cases, NA properties after casting are particularly required.

In this regard, Type 4 has been proposed in the past in order to create a mold with good disintegration properties after pouring, but no one has yet been found that produces a 4-minute effect.

For example, although the addition of acids and urea breaks down the fushi method, it cures the shortcomings such as insufficient decay and low fusion point and shortcomings. However, the inventors have made extensive studies on resin compositions that have good strength V and have a high disintegration V. As a result, they added dicyandiamide, a specific acid, to the phenolic resin, which is the binder component. In this book, we discovered that the addition of 20% of the total amount of 20% of the total amount of molten carbonate increases the amount of collapse F after casting, and that it also provides a mold with high strength because it has low wettability and collapse 4. AT- to complete the invention.

That is, in the bonding component A mainly composed of the phenolic resin of the present invention, 1 to 40 mt part of dicyandiamide is added to 100 small ridges of the phenol resin, resulting in a low-temperature easily disintegrating light metal @ foundry sand. The present invention provides a resin phase composition for use.

Here, we have selected phenolic resins (typical /
+, novolac-type phenol, ]le resin, 3-resol-type funinol, Haruzuki, and phenol, cresol, resolun]-le, bisphenol A, /- is bisphenol. A phenol such as A oligomer or its equivalent substance, formaldehyde, paraformaldehyde, hemethylene detramine or phthylaldehyde, and a formaldehyde supplying substance or its equivalent substance, known in the art. It is obtained by ☆ reaction using a conventional method, and the resin shaped cap is a solid liver-like shape.
It is preferable in terms of power cutting and handling workability.

On the other hand, the dicyandiamide mentioned above has a melting point of 2[9C], and if it is heated at a temperature close to 10 degrees Celsius, it generates intense heat immediately after melting, producing melts of melam, melem, and methane. It has 5 special features to promote the decomposition of the phenolic resin in the mold of the cast body by taking advantage of the fact that it also generates carbon atoms.

The amount of dicyandiamide added to the phenol resin K is usually 1 to 40 parts by weight, preferably 10 to 20 parts by weight, per 100 seams of the phenol resin. Lacquer within the range of. If the amount of diandiamide added is too small, will the U-shape collapse after casting? On the other hand, if the amount of addition is too large, it will be impossible to improve it! Since the strength of the subsequent mold is reduced, the amount added should be appropriately selected depending on the type and size of the binder.

In order to obtain the composition of the present invention by adding the dicyandiamide to the phenolic resin, (11) dissolving or dispersing dicyandiamide in the binder, or (2) mixing the binder and sand. or (3) add a small amount of dicyandiamide to the binder and then mix it together in the process of coating the sand with the binder; or (3) add a small amount of dicyandiamide to the binder and then mix the binder. (4) Methods such as applying a binder in advance and mixing dicyandiamide with the binder can be applied, but the present invention does not produce the same effect with any of these methods. .

Furthermore, in order to manufacture foundry sand using the resin composition obtained by such a non-explosion method, it is also necessary to use the
This is done by the method 4), or by extending the J method of F from the old method 2.

For example, when using method 11 above, dicyandiamide is dissolved or dispersed in the binder in advance and the dicyandiamide-containing bond is added to the composition of the present invention. The desired foundry sand can be obtained by mixing the dicyandiamide-containing binder composition with the dicyandiamide-containing binder composition, or by applying the dicyandiamide-containing binder composition to sand.

The composition of the present invention thus obtained may further contain, if necessary,
Even better effects can be obtained if it is used in combination with other additives such as known and commonly used organic acids, urea or gold salts.

Furthermore, in order to obtain the composition of the present invention, in addition to the above-mentioned phenolic resin, as a binder component, a polyester resin, a flat resin, a Yurike resin, a polyisocyanate compound, starch, etc., which have less heat regenerating properties than the phenol resin, may be used. can be used in combination with other binder components, and each of these substances can also be added when obtaining foundry sand after obtaining the composition of the present invention using only the phenolic resin as a binder component. It can also be used as

By using these other binder components in combination, it is possible to achieve the object of the present invention, particularly a resin composition for foundry sand with good disintegrability, which is no worse than wood.

The original Moeho product! Earth fortitude 1/Nishukuka, power:, @ good f- for the collapse of the result, get a casting god, etc., and the name and I will be able to use aluminum or copper, etc. It is used for foundry sand of Karutani gold.
1st, J non-inventive example, comparative example; All measurements shall be based on the longitudinal joint standard. Also, as silica sand, 810. Purity is 99.5% or more, AFm
The one with a particle size index of 80' is -M.

Example 1 [10 of Foundret To-34o2-o-1 (Novolac-Leenol m fat manufactured by Inu Nippon Ingi Kagaku Kogyo Co., Ltd.)]
0 parts were melted in 15O' and 15 parts of Lesiarelete was added thereto, stirred thoroughly to mix evenly, and cooled to obtain a resin composition.

Next, 100 parts of silica sand was added and heated to 1 to 0°C, and 2.3 parts of the resin composition was passed through a 6-mesh sieve, and 20 mounds were added to the sieve. After adding one phase so that it remained on the Noshu sieve soil, it was kneaded for 1 minute with a whirl mixer.

After that, add 0.3 of hexamethylenetetramine to this.
An aqueous solution prepared by dissolving 1.3 parts of ice in 1.3 parts of ice was added and kneaded for 1 minute, and 0.1 part of calcium stearate was added and kneaded for 20 seconds to obtain a composition for foundry sand.

Example 2 2.
0 parts of Foundlets TD-6402-B and 0.6 parts of dicyandiamide were added. Hereafter, Example 1
The same operation as above was repeated to obtain a composition for foundry sand.

Example 5 2.0 parts of "Foundlets TD-3402-B" was added to 100 parts of silica sand preheated to 150°C, and mixed silkworms were prepared. . Then, repeat the steps in Example 1 and 7 to obtain lip grease-catching sand.

Heide J Symphony Orchestra's stagnation Leangia: Mido. A composition for ghee sand was obtained by adding f.

Example 4 100 parts of phenol and 20 parts of a 37% formaldehyde aqueous solution and 12 parts of a 25% D-1 aqueous solution were mixed into 6
After heating at 5°C for 2 hours, the amount of reaction liquid SQ and unreacted materials were removed by heating and vacuum, and the temperature at 156°C was 9a. Then, it was directly cooled for 6M and solidified to a temperature of 6 h"8°C to obtain 4 fronds of fat.

Next, 2.0 parts of this resin was passed through a 6-mesh sieve, crushed so that it remained on the 20-mesh sieve, and 100 parts of silica sand preheated to 150°C was added to this. The mixture was kneaded for 1 minute using a whirl mixer.

Then, 1.3 parts of water and 0.6 parts of dicyandiamide were added to this, and the mixture was kneaded for an additional 1 minute.
．． One part of calcium stearate was added and kneaded for 20 seconds to obtain a composition for foundry sand.

Comparative Example 1 Example 2 except that no dianediamide was used.
The same operation as above was repeated to obtain a foundry Sunagawa composition for comparison.

Comparative Example 2 The same operation as in Example 4 was repeated except that no dicyandiamide was used to obtain a foundry resin composition for comparison.

Application Examples 1 to 4 and Comparative Application Example 1.2 First, in the case of Application Examples 1 to 6 and Comparative Application Example 1, 23
Examples 1 to 3 and Comparative Example 1 were placed in a mold heated to 0°C.
Each of the casting Sunagawa compositions obtained was poured and held for 2 minutes, and then fired in a 25) C furnace for 1 minute to obtain a mold.

On the other hand, in the case of Application Example 4 and Comparative Application Example 2, Example 4
Except for using the foundry Sunagawa compositions obtained in Comparative Example 2, holding these compositions at 190°C for 6 minutes, and changing the firing time to 2 minutes. Molds were obtained in the same manner as in Examples 1 to 3 and Comparative Application N1.

The fired foundry sand thus obtained was tested on a test heath (8 force m-
This was wrapped in aluminum foil and placed in a furnace at 500° C. for 20 minutes.

Next, each heat-treated test heath was sieved using a low-tag sieve to remove sand on a 10-mesh sieve, and the time (in seconds) until no test pieces remained on the sieve was measured. ), or the ratio (% value) of the amount of sand removed 4 minutes after the start of sand removal to the weight of the test piece before the start of sand removal. It was taken as the disintegration value. The results of these disintegration tests are summarized in Table 1.

The same table also shows the results of the fusion point and bending strength, but these were conducted for each casting Sunagawa composition obtained in Examples 1 to 4 and Comparative Example 1.2. Among them, the fusion point is determined by JACT (Casting Technology Promotion Association) test method c-
On the other hand, the bending strength was measured according to the test method of JISK-6910.

Claims (1)

[Scope of Claims] 1. A low-temperature curable light alloy casting Sunagawa resin composition comprising 1 to 46 parts by weight of dicyandiamide to 100 parts by weight of a phenolic resin. 2 Contains a phenolic resin as the main component of the binder, and contains 1 to 40 parts by weight per 100 parts by weight of the phenolic resin.
To obtain a low-temperature hardening light alloy foundry sand resin composition which also contains 1 part of dicyandiamide, (2) 01 dicyandiamide is dissolved or dispersed in a binder;
In the step of mixing the binder and sand or the step of coating the binder, do you add and mix dicyandiamide with the binder? (3) Add dicyandiamide to the sand in advance and then mix the binder. I'm sorry, but it's too small (
41. A method for producing a low-temperature-curable resin composition for light alloy foundry sand, the method comprising mixing dicyandiamide with sand containing a binder.