SU1500431A1 - Sand for making cores and moulds - Google Patents

Abstract

This invention relates to a foundry, in particular, to compositions of mixtures for foundry cores and molds, preferably cured in a heated or cold tooling. The purpose of the invention is to improve the quality of the mixture by increasing its fluidity and curing speed. The composition of the mixture, wt.%: Binding resin-based composition - product of the synthesis of reactive monomer with formaldehyde and hardener or curing catalyst 2.0 ... 7.0, thermochemically activated vermiculite with a specific surface area of 20 ... 80 m ² / g 0.2 ... 3.1

quartz sand else. The invention allows to increase the fluidity of the mixture by 5 ... 10%, and the rate of combustible curing of the mixture - by 1.1 ... 1.5 times. 4 tab.

Description

FIELD OF THE INVENTION The invention relates to foundry production, in particular, to compositions of sand-resin rods and molds that are curable in cold and heated tooling.

The purpose of the invention is to improve the quality of the mixture by increasing its fluidity and curing speed.

The essence of the invention is as follows.

Vermiculite is a mineral belonging to the group of hydrated aluminoscicates of a layered structure. The chemical composition of vermiculite is not constant because of the presence of isomorphous substitutions in its structure and varies within the following limits, wt%: Si02 3.4-42; AljOj 10-17; FeeO 3-17; MeO 14-25; Feo

1-3, the water content reaches 20%. Natural vermiculite is a homogeneous-fine-pore mineral with a prevailing radius of 15 A. The specific surface is 3-10,

Activated vermiculite is obtained as a result of thermochemical effects: heat treatment at 450-500 ° C and chemical activation with J 0% HgSO solution at the temperature of a boiling water bath for 0.5-6 hours.

This treatment leads to a change in the structural characteristics of vermiculite: due to the delamination of the packets and partial destruction of the layers, the pore radius increases to 20-60 A,. and specific surface area - up to 20: p

4 S

31500431

80 The degree of activation is controlled by the intensity of the thermochemical exposure to temperature and the duration of exposure.5.

Activated vermiculite is characterized by a higher adsorption capacity, which determines its beneficial effect on the kinetic conditions of the mixture curing in the baseline,

Quartz sand is used as a refractory filler.

Depending on the particularities of the technological process of manufacturing 15 rods, different binding compositions are introduced into the composition of the mixture by cold or heated tooling. In mixtures, intended for the manufacture of bulk forms and rods in a heated snap-in, use MFPM carbamide-formaldehyde resin modified with furyl alcohol in combination with catalyst Ml, including wt.%: Ammonium chloride 10; carbamide 45; water 45. In the mixtures intended for the manufacture of cold-hardening molds and rods, Furitol 107 carbamide-furan resin is used in combination with a catalyst — orthophosphoric acid. It is also possible to use other binder compositions in accordance with. specific conditions of production accepted by the respective enterprises. , To make the mixture, the refractory resin is mixed with a catalyst (hardener) and synthetic resin for 1.5-2 minutes after each 40 dosing, then activated vermiculite is added and another 40 40 C is mixed. Further regulation of the mixture remains unchanged and is selected in accordance with the features of the technological process of manufacturing rods and molds in cold or heated tooling.

The embodiment of the invention is illustrated by the example of preparing CQ mixtures for making rods hardening in a heated and cold

tooling, for castings of block-sumps of engines of combines, tractors and automobiles.

The compositions of the mixtures according to the invention, from being hardened in heated and cold tooling, as well as their properties are given in Tables 1-4. Respectively.

The specific surface area of vermiculite was determined using a PSC-2 instrument.

Analysis of laboratory and experimental data showed that the introduction of activated vermiculite with a specific surface area of 20–80 m / g as a processing additive to the composition of the mixture increased the fluidity of the mixture by 5–10% and the curing rate of 1.1–1 5 times.

I.

Claims (1)

Invention Formula The mixture for the manufacture of casting cores and molds, mainly cured in the tooling, including quartz sand, a resin-based binder composition, is a product of the synthesis of reactive monomer with formaldehyde and hardener or a curing catalyst, as well as vermiculite, characterized in that In order to improve the quality of the mixture by increasing its yield and curing speed, the mixture contains thermochemically activated vermiculite with a specific surface of 20-80 m / g in the following ratio of ingredients,% by m: S uyuscha kmpozi- qi resin - synthesis product of a reactive monomer with the formaldehyde and catalyst or curing otverdytel 2,0-7,0 Thermochemically aKTH - i virovanny vermiculite with a specific sur. 20-80m / g Quartz sand Table 1 Cure at C, s Properties  Mixes : i: zr: r 0.47 0.47 0.48 0.59 0.70 0.71 0.72 0.85 1.10 1.33 1.14 1.33 1.73 1.73 1.74 1.95 267267267270 10999 0.27 0.27 0.27 0.25 Compiled by S.Teplkov Editor MoBandura Tehred MLidykKorrek7 Or N.Borisova Order 4807/14 Circulation 711 VNIIGSH of the State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 4/5, Moscow, Zh-35, Raushsk nab. 113035 Production and publishing complex Patent. Uzhgorod, st. Gagarin, 101 Spreadsheets : i: z :: r: ::: i: i :: i: 0.63 -0.90 1.37 2.01 271 8 0.71 1.31. 1.50 2.38 0.25 0.25 273 7 0.72 1.33 1.54 2.40 0.25 275 7 0.72 1.34 1.56 2.41 0.25 275 7 Subscription