SU1676736A1 - Binding compound for cold-curing mould and core sand - Google Patents

Abstract

The invention relates to a foundry and can be used to make casting molds and cores from cold-hardening resin mixtures. The purpose of the invention is to increase the strength of rods and molds in the initial stages of curing and improve sanitary and hygienic working conditions. The binding composition contains May. %: carbamidofuran resin 73-84; VAT residue of periodic distillation of caprolactam 1-2; acidic waste from the production of monochloramine 15-25. The introduction of the periodic distillation of caprolactam and the acidic waste from the production of monochloramine to the composition of the binding composition of the bottoms residue allows modification of the furan resin, increasing its pH, which makes it possible to use highly concentrated p-chlorobenzenesulfonic acid. 3 tab. J

Description

The invention relates to a foundry and can be used to make casting molds and cores from cold-hardening resin mixtures.

The purpose of the invention is to increase the strength of rods and molds in the initial stages of curing and improve sanitary and hygienic working conditions.

The proposed binder composition contains a carbamidofuran resin, a distillation residue for the periodic distillation of caprolactam and an inorganic acid.

The bottoms residue of the periodic distillation of caprolactam (CO MPC) has the following composition, May. %:

Caprolactam 60-75

Sodium salt of e-aminocaproic acid12-20

Sodium hydroxide 2-4

OsmolyEstalnye

QC MPC is a solid light brown color product of the partial polymerization of caprolactam and aminocaproic acid and is a large tonnage waste. During the year, more than 1.0 thousand tons of this waste is accumulated. KO MPC performs the role of a modifier of urea resin. The addition of the modifier KO MPC increases the pH of the resin from 6.4 to 8.7 units., Increases its vitality. Due to the modification of the urea resin, it was possible to use a concentrated acidic waste from the production of monochloramine in the composition of the cold hardening binder composition.

An acidic waste from the production of monochloramine (KO MOA) contains, May. %: Sulfuric acid 50-60

4,4-Dichlorodiphenylsulfan 15-22 "-Chlorobenzene sulfonic acid 10-15 gs-Chlorobenzenesulfonyl chloride 0.6-1.5 Sol peracid 0.2-0.4

Osmoly3,0-9,0

WaterEverything

KO MOSS is a homogeneous liquid of dark brown color with a sweetish odor, density at 20 ° С is 1.61 - 1.66 g / cm3 and.

Acidic waste is formed during the production of monochloramine in the intermediate stage of the target semi-finished product — sulfochloride from -chlorobenzenesulfonic acid and chlorosulfonic acid:

ac6n45o2on + s & o2on

 tC6H4SO2C t + H2SO4.

C ulfa chloride is recovered from the sulphate by decomposition of excess chlorosulfonic acid with water:

CfcSO2OH + H2O H2SO4-r-HC0.

As a result of the difference in density, the reaction mixture by settling is divided into two layers: the upper layer is sulfonyl chloride, the lower layer is sulfuric acid with impurities of various substances (acidic waste). The temperature in the separation tank is maintained between 40-70 ° C to avoid solidification of the sulfochloride melt. The sulfochloride melt goes further into amitators for the amidation reaction to obtain the desired products, chloramines.

Sulphate after neutralization is discharged into the sewer. More than 2.0 kt of this waste is dumped in a year, so there is a large and cheap raw material base for the hardener.

Unlike orthophosphoric acid, KO MHA has a greater catalytic activity. The rate of curing of carbamidofuran resins is strongly influenced by the p-chlorobenzenesulfonic acid and its derivatives contained in the acidic waste.

For the preparation of cold hardening binder compositions, BS-40 kammidofuran resin (TU 6-05-1750-77) is used; solid residues of periodic distillation of caprolactam Dzerzhinsky PO Caprolactam; acidic waste from the production of monochloramine Dzerzhinsky PO "Caprolactam with a density of 1.50-1.60 g / cm3.

The proposed cold hardening binder composition, consisting of the binder itself and the hardener, is prepared separately. First, a binder is prepared.

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By the mechanical mixing of the modifier CO PDK in the BS-40 resin until it is completely dissolved, for example 1.5 May. The% QC MPC is dissolved at 78.5 May. % BS-40. The KO MOA refresher is used at an initial concentration of 20 May. %

In tab. 1 shows the compositions of the binder composition 1-3.

The components of the cold-hardening binder composition — a modified BS-40 resin and a hardener KO MHA — are introduced onto quartz sand separately.

The preparation of XTC is carried out in a laboratory mixer in the following mode. Quartz sand of 1K02 grade (GOST 2189-84) is mixed with the hardener KO MOXA for 1 minute, then the modified BS-40 resin is introduced and the mixing is continued for another 1 minute. The total content of the cold hardening binder composition in CTS is 2.5 May. %

In tab. 2 shows the composition of the mixture with the proposed binder composition.

From tab. 2, it can be seen that the consumption of the proposed cold-hardening binder composition in comparison with the known is reduced by 17%. The reduction in consumption of the cold-hardening binder composition is due to its higher efficiency. This leads to improved sanitary and hygienic working conditions.

In tab. 3 shows the physico-mechanical properties of mixtures 1-3.

Presented in table. 3, it follows that in comparison with the known, the proposed cold-hardening binder composition increases the strength of the rods during the initial stages of curing. The best indicators were obtained when using a cold-hardening binder composition of compositions 1-3 (Table 1) containing 1.0-2 May. % FPK MAC in May 15-25. % KO MOHA. These compositions of the binder composition, in contrast to the known, allow to increase the strength of the rods in the first 30 minutes of hardening by 2-3 times, which improves the quality of the rods and shapes when removing them from the tooling and during transportation.

The proposed cold-hardening composition in comparison with the known provides the following technical and economic advantages:

increasing the strength of rods and molds at the initial stages of curing by 2-3 times;

improving sanitary and hygienic working conditions by reducing the content of the cold-hardening binder composition by 17%.

Claims (1)

Invention Formula Binding composition for the manufacture of casting molds and cores of cold hardening resin mixtures, containing carbamndofuran resin and acid-containing substance, characterized in that, in order to increase the strength of the rods and shapes in the initial stages of hardening and improvement of sanitary and hygienic working conditions, it additionally contains vat residue periodic distillation of caprolactam, and as an acid-containing substance - concentrated acidic waste from the production of monochloramine based on sulfuric acid in the following ratio of ingredients, May. %: Urea acid 73-84 VAT residue periodic distillation caprolactam1-2 Concentrated sour withdrawal from production monochloramine based sulfuric acid15-25 Carbamidofur analogue BS-40 resin Vat residue for periodic distillation of caprolactam Sour withdrawal from the production of monochloramine (square 1.58 g / cm3) Blend Ingredients Quartz sand Holo bottom hardening binder composition one 2 3 Table 1 78.5 73.0 1.5 2.0 20 25 table 2 Content of ingredients,% masa, in mixtures one Izi 97.5 97.5 97.5 2.5 2.5 2.5 Compressive strength, kgf / cm2, through, h 0.5 one 3 6 24 Tensile strength, kgf / cm2, after 1 h Table 3 16.4 25.0 41.5 53.8 73.3 11.7 20.4 39.6 48.0 60.8 12.8 9.2