SU352669A1 - - Google Patents

Description

The invention relates to the field of casting production, more specifically to cold-curing catalysts for sand-resin molding sands for casting cores and molds.

It is known to use as an acidic catalyst for cold curing sand-sand molding mixtures for casting cores and molds containing aromatic sulfonic acid as a binder for phenol-formaldehyde and furylphenol-formaldehyde resins. The catalyst is introduced into the process of preparing a mixture as solutions in water or in some organic solvents. The activity of this catalyst, as measured by the rate of cold curing of the molding sand, is insufficient at the initial stage of cold curing (0.5-1 hour).

In order to increase the rate of cold curing at the initial stage of hardening and strength of the mixture, it was proposed to use an organophosphorus compound of the general formula AgOR (O) X2 as an acid catalyst, where Ar is aryl or aralkyl, and X is halo or hydroxyl.

phosphoric acid in an amount of 0.1 - 0.3 weight. h. on 1 weight. h. resin.

In addition, a technical mixture of substituted phosphoric acid chlorohydrides can be used in the same amounts, but it can be used as an intermediate in the synthesis of phosphoric acid ethers, having the following composition,%: impurities 10-5

Aryl phosphoric acid dichlorohydride and the technical mixture of substituted phosphoric acid chlorides can be used in the initial liquid form or as solutions in non-polar organic solvents such as n-hexane, toluene, xylene (mixture of o, m, p isomers).

Arylphosphoric acid can be used as aqueous solutions in slightly polar organic solvents, such as alcohols and ketones.

100 weight. sand with a resin viscosity of not more than 500-600 spz.

A significant advantage of such organophosphorus compounds is their relatively low cost per weight. h. resin.

Example 1. To prepare the preparation, the components are taken in the following ratios, wt. including:

Quartz sand Lyuberetsky 1K015A100 resin Furylphenol formaldehyde brand FF-1F (dry residue 70%) 2.5 Catalyst (dphlorohydride arylphosphoric acid) 0.7 The order of input of the components in the process of preparing a mixture is as follows.

The catalyst is introduced into the sand and transferred for 1 minute, then the resin is introduced and mixed for another 1-2 minutes, after which the mixture is ready for use.

The molding mixture prepared in accordance with the above recipe has the following properties.

Vitality mixture

Compressive strength across pa, kg / cm: 15 min28.0

1 hour 30,0

24, 0

Both p and measures 2. To prepare the mixture, the components are taken in the following ratios, wt. including:

quartz sand Lyuberetsky 1K015 / 100 resin of phenol formaldehyde resin of the resolvent type, synthesized

in the usual way with an MgO catalyst at an initial ratio of 1.2 mol of formaldehyde to 1 mol of phenol, in which at the final stage of the synthesis 5% (by weight of resin) -y-amino-p-propylene trietho2,5 of xysilane was introduced

catalyst (phosphoric dichloride anhydrous acid, 7 lots)

The order of input of the components during the preparation of the mixture is similar to the indicated B example 1.

The molding mixture prepared in accordance with the above recipe has the following properties.

The vitality of the mixture, min5

Compressive strength through, kg / cm: 30 min4,4

1 hour 11,5

2 47.5

24 51.0

Subject invention

The use of a phosphorus compound of the general formula AgOR (O) X2, where Ar is an aryl or aralkyl radical, and X is a halogen or hydroxyl, as an acid

catalyst for cold hardening molding mixture for casting cores and molds containing a refractory filler and binder selected from the class of liquid resole phenol formaldehyde and

furylphenol formaldehyde resins.