No 12,908 UK Coat of Arms A.D. 1909

Date of Application, 1st June, 1909 - Accepted, 26th May,1910


Process of Producing Colloidal Sols or Gels.

    I, THEODOR SVEDBERG, of Upsala, in the Kingdom of Sweden, Doctor of Philosophy, Fellow of the University of Upsala, do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement:—

    This invention relates to a process of producing colloidal sols or gels.

    Some methods of producing colloidal sols or gels from organic substances are before known. Some of the said processes, for instance those described in the British Patents No. 25,735 of 1906 and No. 14,681 of 1905, are based on the reaction of large quantities of alkali on the substances to be converted into a. colloidal state, whereby on account of the mere chemical action of the strong alkali, the substances which are finally brought into the colloidal solution cannot be said to be chemically identical with the substances originally treated.

    A process has also been suggested for producing colloidal solution in which a crystalloidal solution of the substance to be treated is gradually added and thoroughly mixed with a boiling mixture of soap, starch and water so that the solvent volatilizes. In this process starch may be replaced by cereals or other colloids and soap may be replaced by aqueous solutions of alkalies, alkali earths, borax and fats, resins, varnishes, oils, waxes, balsams, paraffins, or saponine solutions and the like.

    All the processes hereinbefore referred to are thus based on the employment, besides the substance to be dissolved, the solvent of the crystalloidal solution, and the dispersion means, of an auxiliary means, such as alkali, soap, or a colloid, for instance starch.

    On the other hand, it is also before known that dilute liquid sols may be obtained from certain substances, such as mastic and some other resins, by dripping the ethyl-alcoholic solutions of the said substances into water. By such a procedure, it is, however, only in few cases possible to obtain colloids and even in such cases only in an imperfect and unstable form.

    The object of the invention is to provide a general method of producing liquid or solid colloidal sols or gels.

    The invention consists, chiefly, in heating a crystalloidal solution of the substance to be converted into the colloidal state, bringing the heated solution into a likewise heated quantity of a dispersion means (external phase), removing the solvent in any suitable manner, for instance by boiling, and reducing the obtained sol by evaporation to the concentration required. If desired, a protecting colloid may thereupon be added, according to known principles, or the liquid sol may be converted by evaporation of the imbibition liquid, into a dry sol, or, by adding an electrolyte, into a gel. It is to be noted that the substances to be brought into a colloidal state all the time maintain their molecular structure.

    The solvent may consist of any suitable matter in which the substance to be converted into a colloidal state is soluble as a crystalloid and which is, moreover, wholly or partially mixable with the dispersion means (external phase). As a. dispersion means a simple liquid or a mixture of simple liquids not previously containing any colloids may be used in which the substance to be converted into a colloidal state is insoluble as a crystalloid. Thus, for instance, if wax is the substance to be converted into a colloidal state, and water is the dispersion means, I may use ethyl alcohol as a. solvent. If caoutchouc is the substance to be converted into a colloidal state and ethyl alcohol is the dispersion means, the solvent may be, for instance, benzol.

    The process may be carried out in the following manner:

    The substance to be converted into the colloidal state is dissolved as a crystalloid in a suitable solvent, which may consist of a single chemical compound or of a mixture of such compounds (two or more), whereupon the solution is heated to a temperature dependent in each case on the physical-chemical properties (such as melting points, boiling points etc.) of the said substance as well as on those of the solvent and the dispersion means employed. The dispersion means by which the disperse phase (internal phase) is to be permanently or temporarily obtained, is heated to a suitable temperature dependent on the factors herein before set forth. The crystalloidal solution is thereupon brought into the dispersion means. This operation should in some cases, for instance when colloids of a small size of the particles are desired, be carried out so slowly that the quantity of the solvent brought into the dispersion means may be kept, for instance by continued or periodical boiling or evaporation, below such a limit that the mixed liquid obtained is not able in a considerable degree to dissolve as a crystalloid in the disperse phase (internal phase). The solvent is finally removed from the liquid sol obtained so that the latter obtains the purity which in each case is considered necessary whereupon the sol is reduced by evaporation to a suitable concentration.

    Thus, if a colloidal solution of wax in water is desired, a more or less saturated alcoholic solution of the said substance is first produced in usual manner, said solution being kept as near the boiling point of the alcohol as possible, whereupon the alcoholic solution is gradually added to the water, which is, preferably, kept boiling, In adding the alcoholic solution to the boiling water it is to be observed that the percentage of alcohol in the water is always kept below a certain limit. When the water solution has obtained the desired wax concentration, the supply of alcohol is shut off, whereas the boiling is continued until the solution is quite free from alcohol, even a very small quantity of alcohol acting to diminish the durability of this colloidal solution.

    By adding an electrolyte the colloidal sols obtained by this process may be converted into the corresponding gels. In some cases it is desirable to increase the stability of the sols obtained which is performed by adding protecting colloids. If such an addition, for instance of gum, has been made and the liquid sol has been reduced to dryness by evaporation, a solid sol is obtained which may again be dissolved in usual manner in a suitable dispersion means.

    Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:—

    The process of producing liquid or solid colloidal sols or gels, while maintaining the molecular structure of the substances to be converted into colloidal state, characterised in that a crystalloidal solution of the substance to be converted into the colloidal state is heated and then brought in its heated condition into a heated dispersion means which does not previously contain any colloid, the solvent being thereupon removed in known manner, for instance by boiling, and the sol obtained reduced by evaporation to the concentration required.

        Dated the 18th day of May, 1909.
285, High Holborn, London, W.C., and at
Liverpool and Bradford,
Patent Agents for the Applicant.

Redhill: Printed for His Majesty’s Stationery Office, by Love & Malcomson, Ltd. — 1910

Similar patents were also filed on the same day 1 June 1909, in
Switzerland (No.49141) Verfahren zur Überführung von Körpern in den kolloiden Zustand
Austria (No.45193) Verfahren zur Herstellung von kolloidalen Lösungen.
Denmark (No.12767) Fremgangsmaade til Fremstilling af kolloidale Soler eller Geler.