SU768530A1 - Mixture for producing casting moulds and cores in heatable equipment - Google Patents

Description

one

The invention relates to a foundry, namely, the compositions of the mixtures used to make foundry cores and molds on a heated tooling.

The use of phenol-alcohols in 5 as a binder is known in the form of a composition that includes urea and ammonium chloride 1 in addition to phenol-alcohol.

A characteristic feature of sand-resin mixtures with this binder is 10 significant release of free phenol and relatively slow cure.

Closest to the described invention by its technical essence and the achieved result is a mixture for making casting cores and molds on heated equipment, containing a refractory filler and a composition of phenol alcohol (phenol alcohol, ammonium chloride and urea in a weight ratio of 20 100: 0.5: 20) 2.

This mixture provides sufficiently high physicomechanical parameters in the cured state, however, it is characterized by a significant release of phenol in the manufacture of rods and a relatively low curing rate, which reduces its effectiveness in the conditions of modern mass production of castings. zo

The purpose of the invention is to reduce the release of phenol vapor into the air and, on this basis, to improve sanitary and hygienic working conditions.

To achieve this goal, the mixture for making casting cores and molds in heated equipment, including a refractory filler and a binder — a solution of urea and ammonium chloride in phenol alcohol, taken in a weight ratio of 20: 0.5: 100, respectively, additionally contains an aqueous solution of ferric chloride density of 1.40-1.55 g / cm in the following ratio of ingredients, weight. %:

A solution of urea and ammonium chloride in phenol-alcohol1, 0-5.5 Aqueous solution of ferric chloride with a density of 1.40-1.55 g / cm3 0.1-1.5 Refractory filler Else The use of industrially produced technical products is provided as phenol-alcohol. , B and B (TU-6-05-1164-72).

Ferric chloride is introduced in the form of an aqueous solution with a density of 1.4-1.55 g / cm (technical ferric chloride, Spec. 11-76).

The riprt content of ferric chloride below the lower limit of its positive effect on reducing the amount of phenol released in the manufacture of rods, is not sufficient, and when its content is above the upper limit, a sharp decrease in the mechanical and technological properties of the mixture is observed.

The binding of free phenol is based on the interaction of phenol with ferric chloride by the exchange reaction:

Oho

he

3 (o) - FeClj-O) - 0-Ge n ZNS1 f

The increase in strength is explained by the fact that the substitution of hydrogen atoms of hydroxyl groups by ferric ions significantly changes the structure of the polymer and contributes to the formation of polymers of a network structure having higher strength. This reduces the content and mixtures of phenol-alcohol and thereby further improves the hygiene and hygiene properties of the mixture.

The order of introduction and transfer of ingredients in the mixture preparation process

It is common in the practice of preparing sand-resin mixtures that are curable in a heated snap-in: first, the refractory filler (quartz sand) is moved with a solution of chlorine

iron, and then administered the composition of phenol-alcohol.

The preparation of mixtures containing chlorine bleu is illustrated by the following example.

In tab. 1 shows the compositions of the proposed mixtures No. 1-3 and known mixture No. 4.

Table 1

) Phenol-alcohol: urea: ammonium chloride 100: 20: 0.5 (by weight)

Modes of hot curing:

equipment heating temperature, ° С250 ± 10

the duration of exposure of the mixture in a snap, with 120

Table

Mixtures 1 and 3 are used in the manufacture of simple

rods.

When the mixture 3 containing the largest amount of the phenol-alcohol composition is cured, the least amount of phenol is released due to the high content of ferric chloride in the mixture. The low strength is due to the partial destruction of the polymer due to an excess of hydrochloric acid.

Claims (2)

The properties of mixtures Nos. 1-4. The content of free phenol released during the preparation of the samples and their strength in the cooled state are shown in Table. 2. From the data table. 2 shows that the proposed mixture as compared to the known one provides a decrease in the amount of phenol released during curing of the mixture not less than 2 times (with an equivalent content in the mixture of phenol alcohol composition), as well as an increase in the strength of the mixture by 25-30% ( compare the values for mixtures No. 2 and 4 with the equivalent content of the phenol-alcohol composition). By reducing the release of phenol into the air, sanitary and hygienic working conditions are improved on the core sections of foundries. Claims of the Invention A mixture for making casting cores and molds in a heated snap-in comprising a refractory filler and a binder-solution of urea and ammonium chloride in phenol-alcohol, taken in a weight ratio of 20: 0.5: 100, respectively, characterized in that reducing the excretion of phenol vapors into the air and improving on this basis sanitary and hygienic working conditions, it additionally contains an aqueous solution of ferric chloride with a density of 1.40-1.55 g / cm with the following ratio of ingredients, weight. %: Solution of urea and ammonium chloride in phenol-alcohol1, 0-5.5 Aqueous solution of ferric chloride with a density of 1.40-1.55 g / cm3.1-1.5 Refractory fillerOthers References taken into account during the examination 1. Author certificate number 206801, cl. In 22C 1/00, 1964. 2. "Foundry, 1968, No. 7, p. 6-8 (prototype).