FR2575743A1 - Synthetic binder based on thermoplastic resins and process for its manufacture - Google Patents

Abstract

Binders based on thermoplastic resins, intended for agglomerating or adhesively bonding mineral, vegetable and/or synthetic aggregates or substances. The binder is obtained by adding inorganic additives to one or a number of thermoplastic resins, whose effect is to increase the physical performance of the resins, in particular the wettability and the bonding. The product according to the invention is more particularly employed in the building industry and in public works.

Description

 The present invention relates to binders based on thermoplastic resins for agglomerating or bonding aggregates or inorganic, plant and / or synthetic bodies.

 The known products intended to agglomerate the aggregates are: 1- Bitumen: despite its wide use, bitumen has many disadvantages: - it requires a thorough preparation of the soil and a multiplicity of work of preparation and implementation, - it has low resistance to compression, tensile, bending, cold, heat, acid action, - it lacks flexibility, hardness and tightness, - it requires careful maintenance and expensive.

2- Special bitumens: products that are not widely used and obtained by adding thermoplastic resins and various additives to the bitumen, in varying proportions, in order to increase their performance. The resulting product is expensive and only solves some of the previous disadvantages.

3- Cement: a very widespread product, but one which also has drawbacks: - its use requires formwork and large quantities of water, - the phenomenon of shrinkage and expansion, cold and heat, requires expansion joints; - its tensile strength is moderate and at low flexion.

4- Thermoplastic resins: various tests have been made but to date none gives satisfactory results in wettability, bonding and mechanical performance.

 The synthetic binder which is the subject of the present invention reduces or eliminates most of the above disadvantages and has a very large number of advantages, namely: it can be manufactured cold or hot and marketed in bags, such as cement, in the form of a spray or granuuse or other. It is therefore easy to store, transport and use since it is mixed with the aggregates only before implementation and this at the mixer, at a temperature between 100 and 2000C. In addition, it uses the same material as that used for the implementation of asphalt mixes; 2- its exceptional qualities of wettability and attachment allow its use with any type of aggregate: sands, gravel, stones, earth, plants, etc; 3- The resulting resin concrete combines the qualities of plastic (flexibility) with that of aggregates (hardness) which allows it to undergo, without breaking, the malformations of the subsoil.

Its high compressive strength allows it to be a carrier liner.

 It has exceptional qualities: - great resistance to compression, traction, flexion, temperature and the action of chemical agents (acids, hydrocarbons); - good sound insulation, easy coloring.

 The synthetic binder (L) which is the subject of the present invention uses, as base material, one or more thermoplastic resins (R): polyethylene, polypropylene, polyvinyl chloride (PVC), vinyl acetate-ethylene (EVA), etc.

The best results have been obtained with EVA dosed at about 18% of vinyl acetate.

In view of the fact that thermoplastic resins have no interesting characteristics of wettability, tackiness and mechanical strength, it was necessary to try a number of additives to improve their characteristics.

The wettability of the thermoplastic resins between 100 and 200 ° C. has been improved by the use as additives: on the one hand of sodium chloride NaCl and / or of sodium carbonate Na 2 CO 3 on the other hand of feldspar by action of Na20 and K20 contained therein.

Excellent results have been obtained with sodium feldspar from the Eastern Pyrenees whose composition is as follows: SiO 2 (65.5%) - Al 2 O 3 (19.5%) - Fe 2 O 3 (0.35%) - TiO 2 (0, 30%) Ca0 (0.8%) - Mg0 (0.30%) - K20 (4.2%) - Na2O (7.8%).

The mechanical strength of thermoplastic resins (R) has been significantly improved by the use of another additive: iron ore (siderite) also coming from
Pyrénées Orientales and whose composition is as follows:
Fe (36.32%) - SiO 2 (1.58%) - CaO (7.78%) - Al 2 O 3 (0.48%) - MgO (3.87%) - Mn (3 X 1%) - K (0, 07%) Dolomite (46X8%): 1a dolomite being a double carbonate of calcium and magnesium.

The action of alumina contained in feldspar is also important in improving the performance of thermoplastic resins.

Excellent results were obtained with the following composition: - 500 kgs of aggregates of particle size 0-10 - 25kgs of EVA at 18% - 0.175 kg of feldspar - 0.050 kg of siderite - 0.025 kg of sodium chloride, in other words : - additives among them: 10% of (Na) + 20% of (Fe) + 70% of (Fd) - additives with respect to the weight of resin: overall 1% - binder with respect to the weight of the aggregates: 5%
The corresponding results are given in the table below, which at the same time compares with bitumen-based and cement-based concretes.

<Tb>

<SEP> DESIGNATION <SEP> BITUMEN <SEP> CEMENT <SEP> RESIN
<tb>% <SEP> of <SEP> binding <SEP> 6.5 <SEP> 13 <SEP> 5
<tb> density <SEP> 2,2 <SEP> 2,5 <SEP> 2,3
<tb> compression <SEP> HARD <SEP> (bars) <SEP> 80 <SEP> 250 <SEP> - <SEP> 250 <SEP> mini
<tb> indirect <SEP> tensile <SEP> (bars) <SEP> 10 <SEP> 18 <SEP> 30 <SEP> mini
<tb> compression <SEP> MARSHALL <SEP> (kg / cm) <SEP> 1300 <SEP> - <SEP> 5000 <SEP> mini
<tb> deformation <SEP> MARSHALL <SEP> (mm) <SEP> 1.20 <SEP> 1.00
<tb> resistance <SEP> to <SEP> -20 C <SEP> break <SEP> removal <SEP> without <SEP> effect
<tb> resistance <SEP> to <SEP> +60 "C <SEP> softening <SEP> dilation <SEP> without <SEP> effect
<tb> resistances <SEP> to <SEP> acids <SEP> deteriorates <SEP> deteriorates <SEP> without <SEP> effect
<Tb>
Depending on: - the nature and granulometry of the aggregates (A) - the nature of the thermoplastic resins (R) - the nature and proportions of the bodies used in the composition of the additives (C), the previous basic proportions may vary: - for additives in relation to resin weight: 0.3
at 5% - for resins in relation to the weight of aggregates: from 2
at 15%
As for the additives between them: they can vary in large proportions, or even disappear for (Fe) and / or (Fd) but with lower performance for the product or products obtained.

It is possible: - either to mix (R) (Na) (Fd) and (Fe) between 100 and 2000C to give the binder (L) ready for use, - or to mix, at the level of the mixer, directly ( R) (Na) (Fd) and (Fe) at aggregates (A) preheated between 100 and 200 ° C.

Mineral additives (M) with known effects, for example magnesium oxide for the dispersion or silica for the binding, can be added to the binder without departing from the scope of the present invention.

Asphalt may optionally replace, in greater or lesser amounts, some of the resins (R).

The binder thus obtained can be used for the manufacture of mixes, agglomerates, conglomerates and concretes. Its applications can be many: roads, tracks, platforms, reefs, etc.

The synthetic binder (L) can also be used to bond mineral, vegetable and / or synthetic bodies by heating it between 100 and 200 ° C.

The invention is not limited to the embodiments described above and may include alternative embodiments.

 The product according to the invention is more particularly used in building and public works.

Claims (9)

 Synthetic Binder (L), intended to agglomerate or glue aggregates or bodies (A) mineral, vegetable and / or synthetic, characterized in that it comprises: - as base material: one or more thermoplastic resins ( R), as additives: at least one body belonging to the group (Na) of sodium and its compounds or derivatives.  2- synthetic binder (L) according to claim 1, characterized in that the base material (R) is vinyl acetate-ethylene (EVA) more or less metered vinyl acetate.  3- synthetic binder (L) according to one of claims 1 and 2, characterized in that the additive, belonging to the group (Na), is sodium chloride and / or sodium carbonate.  4- synthetic binder (L) according to one of claims 1 to 3, characterized in that a body, belonging to the group (Fd) of feldspars and its compounds or derivatives, is added to (R) and ( N / A).  5- synthetic binder (L) according to one of claims 1 to 4, characterized in that a body, belonging to the group (Fe) of iron ores, containing among other dolomite, is added to (Fd ) and / or (R) and (Na).  6- synthetic binder (L) according to one of claims 1 to 5, characterized in that the additives (Na) and (Fd) and / or (Fe) are mixed with the base material (R) in proportions between 0.3 and 5% of the resin weight (R), either at room temperature or at a temperature between 100 and 2000C.  7- synthetic binder (L) according to claim 6, characterized in that it can agglomerate aggregates () mineral, plant and / or synthetic, previously heated in a kneader between 100 and 2000C, in proportions of binder (L ) between 2 and 15 of the weight of the aggregates (A).  8- synthetic binder (L) according to claim 7, characterized in that bitumen can replace, in greater or lesser amounts, a portion of the resins (R)  9- synthetic binder (L) according to claim 6, characterized in that it can weld bodies (A) mineral, vegetable and / or synthetic, heating it between 100 and 200 "C.