US2666685A

US2666685A - Mold release emulsion

Info

Publication number: US2666685A
Application number: US238574A
Authority: US
Inventors: Maurice C Hommel; Chester C Currie
Original assignee: Dow Corning Corp
Current assignee: Dow Silicones Corp
Priority date: 1951-07-25
Filing date: 1951-07-25
Publication date: 1954-01-19
Anticipated expiration: 1971-01-19
Also published as: FR1065356A; GB710033A

Description

fatented jan- No Drawing. Amiucatfiiuiy Serial No. 238374 .il f ilt zf suitable use. injhe Croning process for .sand

Fea ts. s .Q s n. and san p 'bm ex tlr e el pe S; fiultahleresins r s z m, cure and eject the comple ed sliell molds has made the sand casting process available 'for mass production of metal parts. {is a result,- this process has become 'siohs sweeterteeteh aseasnetresp ss cleaning becomes necessary. Thus; the mowing":

machine is closed down from time to time to clean the master pattern. This entails a loss to production and an increase to unit cost. Actually, mold build-up indicates the failure of the release agent to entirely separate all of the molding from the pattern. The amount of mold material left on the pattern on any single release is, of course, very small.

It is the object of this invention to largely eliminate the above mentioned mold build-up and thereby to effect greater efficiencies and lower production costs.

' This invention concerns a mold release emulsion composed of 1 to 75 per cent by weight of organopolysiloxane fluids, 1 to 6 per cent by weight emulsifying agents, 2 to per cent by 7 LMichs assigngrs to lj 'ow'ffli irnm n Midland, Mich; "a; orneratidii'df "eels-gases reassess P esses empiqastasm -aiiej d. t m alma ter. metal.

pattern lresults ultimately in altering the dimen weight finely divided silica and 20 to 90 per cent water.

The org'anopolysiloxane fluids suitable for use inc-+3832) co" blymers thereof are "sealants thi tiQn Inaddition; thesiloxanesmay co ited amounts of m onoorganpsiloxane un which we "ergaiis' rsaica-l etliy j, phenyl. The defined siloxan'es may" ha e" y vi osity but preferably they haveviscositi's in essa es? .199 team e ntistq sesl qase hias. latpmac 529 mm a 11 6 ...ium fili -S.

The emulsifying agent vention are commercially available materialsand ay he. oicither th cationier anionieprsnonioric We--. males qis elsma erials w ch. ,lr lo erative are morpholinesalts of fatty; ci wher in t fatt c contains ro is amine acetate, n-octadecen'yl y p0 ye er y 7 kali metal salts of alkylated arylpolyether sul-" fates. A commercial sodium salt of an alkylated arylpolyether sulfate is available under the tradename of Triton '7 71.

The order in which the various ingredients of applicants composition may be added can be varied. The preferred method of preparation, however, is as follows:

The organosiloxane fluid and part of the emulsifying agent are mixed in an agitator. Separately, "water and the balance of emulsifying agent are also mixed together by suitable means. The water phase is then added to the siloxane phase, stirred and passed through a colloid mill, homogenizer or the like. This dispersion is finally added to silica well wet with water and again passed through suitable dispersing means. This mold release composition in its emulsion form may be applied in manners well known to the art such as by brush or spray.

The following examples show how this invention may be practiced. These examples are illustrative only and the invention is in no way limited by them.

Example 1 A mold release emulsion was prepared in the following manner: 1.25 pounds of oleic acid and 17.75 pounds of dimethylsiloxane fiuid were mixed in an agitator. In a separate container 0.25 pound of a sodium alkylated arylpolyether sulfate and 0.875 pound of morpholine were dissolved in pounds of water. This water solution was then added to the siloxane-oleic acid and agitation continued until homogeneity was obtained. The resulting mixture, which may be called the thick phase, was passed through a colloid mill. Separately, 2.25 pounds of an aerogel, commercially known as Santocel C, was thoroughly wet down with 23.125 pounds of water. The thick phase containing the polysiloxane was added to the wet-down Santocel and suitably mixed and then dispersed by means of a colloid mill. The foregoing process resulted in an emulsion having the following composition in percentages by weight:

Per cent Dimethylsiloxane fluid 35 Santocel C (Silica aerogel) 4 /2 Qleic' acid 2 Morpholine Sodium salt of alkylated arylpolyether sulfate (Triton 771) Water 56%,

Example 2 Compositions corresponding to that of Example 1 were prepared using the following commercial silicas:

LudoxColloidal silica,

water HiSil-Precipitated silica gel Superflos-Diatomaceous earth DegussaFumed silica dispersed (30%) in All of these compositions gave excellent release when used in the Croning or shell molding process, and they gave no indication of mold build- 4 Example 3 Mold release emulsions were prepared in the proportions and manner of Example 1 using the following polysiloxane fluids:

Diethyl siloxane Phenylmethyl siloxane Ethylmethyl siloxane All emulsions prepared gave excellent release and were free of mold build-up when tested in the Croning process.

That which is claimed is:

1. A mold release emulsion consisting essentially of (1) from 1 to per cent by weight of organosiloxane fluids, said organosiloxanes having from 1.9 to 3 hydrocarbon radicals selected from the group consisting of methyl, ethyl and phenyl radicals, per silicon atom, (2) from 2 to 20 per cent by weight finely divided silica, (3) from 1 to 6 per cent by weight emulsifying agents selected from the group consisting of morpholine salts of fatty acids having from 12 to 18 carbon atoms in the acid chain, acetates of n-primary amines having from 12 to 18 carbon atoms in the amine chain, monoesters of polyethylene glycols and fatty acids having 12 to 18 carbon atoms in the acid chain, alkylated aryl polyether alcohols and alkali metal salts of alkylated aryl polyether sulfates and (4) from 20 to per cent by weight water.

2. A mold release emulsion as in claim 1 wherein the organosiloxane fluid is dimethylsiloxane.

MAURICE C. HOMMEL. CHESTER C. CURRIE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,462,242 Webb et al. Feb. 22, 1949 2,523,281 Currie Sept. 26, 1950 2,529,835 Dailey et al. Nov. 14, 1950 2,549,535 Skooglund Apr. 17, 1951 2,573,337 Hyde Oct. 20, 1951 OTHER REFERENCES The Foundry, August 1950, pages 106, 107 and 212.

Dow Corning Silicone Mold Release Agents, pages 6 and '7.

Claims

1. A MOLD RELEASE EMULSION CONSISTING ESSENTIALLY OF (1) FROM 1 TO 75 PER CENT BY WEIGHT OF ORGANOSILOXANE FLUIDS, SAID ORGANOSILOXANES HAVING FROM 1.9 TO 3 HYDROCARBON RADICALS SELECTED FROM THE GROUP CONSISTING OF METHYL, (2) FROM 2 TO PHENY RADICALS, PER SILICON ATOM, (2) FROM 2 TO 20 PER CENT BY WEIGHT FINELY DIVIDED SILICA, (3) FROM 1 TO 6 PER CENT BY WEIGHT EMULSIFYING AGENTS SELECTED FROM THE GROUP CONSISTING OF MORPHOLINE SALTS OF FATTY ACIDS HAVING FROM 12 TO 18 CARBON ATOMS IN THE ACID CHAIN ACETATES OF N-PRIMARY AMINES HAVING FROM 12 TO 18 CARBON ATOMS IN THE AMINE CHAIN, MONOESTERS OF POLYETHYLENE GLYCOLS AND FATTY ACIDS HAVING 12 TO 18 CARBON ATOMS IN THE ACID CHAIN, ALKYLATED ARYL POLYETHER ALCOHOLS AND ALKALI METAL SALTS OF ALKYLATED ARYL POLYETHER SULFATES AND (4) FROM 20 TO 90 PER CENT BY WEIGHT WATER.