FR2846960A1 - Manufacture of plaster and cement products that are light and biodegradable using a mixture of conventional plaster or cement and a gel of stabilised biodegradable starch and heat treatment - Google Patents

Abstract

The manufacture of plaster or cement products with light and intrinsically biodegradable characteristics consists of: (a) the conventional production of a plaster or cement mixture; (b) incorporating a gel of stabilised biodegradable starch; (c) producing an expansive mixture of the gel and the plaster or cement by working; (d) the immediate casting of the expanded mixture on a support or mould; (e) the immediate heat treatment of the mass by raising the temperature; (f) maintaining the heat treatment until the mixture has solidified; (g) drying the moulded product obtained.

Description

i The present invention relates to a formulation as well as to its method of

  realization for the manufacture of products consisting mainly of plaster or

  cement in order to obtain characteristics of lightness and intrinsic biodegradability.

  Numerous processes are already known for producing plaster or light cement products, most often by incorporating low density aggregates or by

  various chemical reactions requiring heat treatment at high temperature.

  However, in the use of these known methods, results are obtained which in terms of speed of execution, costs and biodegradable structure cannot

  satisfy an industrial product as desired.

  The object of the present invention is to remedy these drawbacks mentioned above in order to allow the use of products consisting of plaster or cement having characteristics of lightness, of intrinsic biodegradability favorable to

  the environment and satisfying economic industrial production.

  To this end, according to the invention, the process for formulating and producing the products is remarkable in that: - we start with the conventional production of a plaster or cement keeper, - we incorporate, at the end of the keeper , a stabilized biodegradable starch gel, - an abundant mixture of the gel and the said keeper is produced by turbination, - the said expanded mixture is immediately poured into its support or mold, - mass heat treatment is immediately carried out on the said mixture by raising the temperature, the heat treatment is maintained until the said mixture is fixed by solidification,

  - drying of said molded product obtained is carried out.

  Thus, in accordance with the invention, industrial products based on

  plaster or cement having the above characteristics.

  Furthermore and in accordance with the present invention, it will be noted that: depending on the desired result, it is possible to incorporate in variable proportions the said starch gel stabilized from 1% to 50% of the weight of the cement or plaster "used, varying proportionally the reduction and intrinsic biodegradability of the product; - similarly and in part for similar effects, it is possible for this starch gel composed mainly of water and starch to consist of a mixture of 30 to% of water and in addition to the above effects. previously stated, it will be possible to increase the flexibility and fluidity of said mixture, - similarly but differently to the results to be obtained, it is possible to add other additives to the starch gel, thus conferring other characteristics on the final product such as coloring. , hydrophobic treatment, film-forming. Thus, in accordance with the present invention, we note that by incorporating the starch gel, it becomes possible to include a large amount of water without it being in the free state within said mixture , thereby constituting water reserves that should be vaporized by raising the temperature. On the other hand and in accordance with the present invention, it is possible, or even recommended, to incorporate the gel as intimately as possible, thus taking into account the incorporation of the starch gel and its film-forming characteristic. , it is possible, by turbination, to produce an expansion of said mixture thus generating micro-bubbles of air within said mixture, each generating a primer for expansion during the heat treatment and thereby creating a fine homogeneous network

  of micro-cavities within the final product.

  On the other hand, and in accordance with the present invention and in order to carry out the heat treatment, an energy preferably operating simultaneously throughout the mass will be chosen. In the specific case, the use of electromagnetic waves is recommended. Thus, after pouring the mixture, a strong energy of electromagnetic waves will be applied immediately and before any solidification of said mixture in order to vaporize instantaneously the water reserves contained in the starch gel, reaching the most spontaneously possible a temperature between 1000C and 150'C in the mass of the product. This will result in an expansion due to the dimensional increase of the micro-bubbles by pressurization linked to the vaporization of the water while the materials thus heated will fix very quickly, thereby allowing the production of a plaster-based product.

  or light cement with intrinsic biodegradability characteristics.

  We will note that the vaporization of the water is preferably that contained in the starch gel allowing the cement or plaster of the said mixture to retain a quantity of water sufficient for its own reaction thereby avoiding a

  significant embrittlement due to too rapid shrinking when set.

  To conclude, such an embodiment obtained by the addition of starch with biodegradable and hydrophilic characteristics thereby authorizes the production of a product with intrinsic biodegradability characteristics as a function of the amount of starch used.

Claims (8)

claims   1) Production method for the manufacture of products mainly consisting of plaster or lightened and biodegradable cement intrinsically characterized in that: - one begins with the conventional production of a plaster or cement keeper, - one incorporates, at the end of keeper, a stabilized biodegradable starch gel, - an abundant mixture of gel and said keeper is produced by turbination, - the said abundant mixture is immediately poured into its support or mold, - mass heat treatment is immediately carried out by temperature rise, - the heat treatment is maintained until the said mixture solidifies,   - drying of said molded product obtained is carried out.   2) The manufacturing method according to claim 1, characterized in that the amount of starch gel added to the waste of plaster or cement is between 1% and 50% of the total mixture.   3) manufacturing process according to one of claims 1 or 2 characterized in that   that the amount of water contained in the starch gel is between 30% to 75% in weight of total gel mixture.   4) manufacturing process according to claims 1 to 3, characterized in that   to the starch gel, any additive can be added   ) Manufacturing method according to claims 1 to 4, characterized in that   the said mixture is immediately expanded by turbining.   6) The manufacturing method according to claims 1 to 5, characterized in that the said expanded mixture is poured immediately into its mold or support.   7) manufacturing method according to claim 1, characterized in said treatment   immediate thermal is obtained by the action of microwaves.   8) The manufacturing method according to claims 1 and 7, characterized in that the   said heat treatment is carried out at a temperature between 100 and 150 ° C.   9) The manufacturing method according to claims 1,7,8, characterized in that the   heat treatment is carried out until the said mixture solidifies.