LU82929A1 - POLYESTER-BASED RESIN COMPOSITIONS WITH IMPROVED SHRINKING PROPERTIES, PREPARATIONS CONTAINING THE SAME AND THEIR APPLICATION - Google Patents

Description

The present invention relates to improvements made to polyester-based resin compositions in order to increase their shrinkage properties.

It is well known that compositions based on commercial polyester resins exhibit shrinkages after their application of the order of 8 to 12%.

Polyester, by its chemical nature, in particular as a result of the good covering and protective properties which it possesses, constitutes a useful material in numerous fields of application.

This is how we can for example consider the use of this type of product for the protection of concrete in sewer installations, sewage treatment plants, on roads or bridges, etc.

When a resinous preparation based on polyester resins is applied to concrete, it is generally impossible to obtain good adhesion because by drying, the covering film undergoing a linear shrinkage of the order of 10% does not not continue to adhere to the concrete base support 5 and flakes off.

We are therefore led to have to use other solutions such as epoxy resins which do not exhibit this shrinkage phenomenon and which are consequently widely used for coating concrete.

The present invention aims to provide a composition based on polyester resins whose shrinkage characteristics are better and particularly compositions of polyester resins whose shrinkage characteristics are practically zero.

As will be indicated below, the present invention also extends to preparations containing such compositions, obtained for example by mixing with sand and, ........

gravel (resinous concrete) or with pigments (paint).

The invention finally extends to applications of this type of compositions or preparations for different uses.

The compositions of the invention are characterized when they contain at least 50%, preferably 65 to 85%, of a commercial polyester resin as well as at least 20% of a mixture consisting of 50 to 85% of mixed styrene. with 50 to 20% polystyrene.

The resins mentioned, namely polyester and polystyrene are usual commercial products having conventional degrees of polymerization, as obtained by the most common methods.

For the preparation of said composition, the polystyrene is dissolved until the styrene is completely dissolved at room temperature or, if necessary, with moderate heating and this solution is then mixed with commercial polyester.

In principle, the polyester has an initial viscosity of 600 cp at 20 ° C, the mixture of styrene and polystyrene is chosen so as to be in the form of a solution with a viscosity of 750 cp at 20 ° C.

By way of example of the commercial polyester preparations which can be used, mention may be made of the various preparations of the "LEGUVAL" type from Bayer.

. The polystyrene can itself be constituted by a commercial granulated polystyrene such as the conventional products sold by the firms BAYER, BASF.

The complement to reach 100% can be constituted i by the usual products added in this type of resins such! that in particular:! ; plasticizers, thinners, stabilizers against aging, light, UV, fillers, etc.

'. For the implementation of this preparation ...... t ^ vr "·" '"' '' -JiWi [j it is suitable in the usual way for the use of polyester resins to add a hardener and an accelerator The accelerator may already be added at the start in the composition, the hardener being added at the time of application of the product.

This product can be applied by spraying, for example by spraying with compressed air or "air-less" spraying or can be applied simply by brush or roller.

For their implementation, other materials such as sand and gravel may be added to the above preparations in order to obtain resinous concrete, in accordance with the usual specifications for this type of product.

This resinous concrete can be more pigmented to give it color.

According to another alternative embodiment of the invention, pigments and / or diluents are added to said composition of matter in order to obtain a paint or a coating.

The essential characteristic of the compositions of the invention · and of the abovementioned preparations lies in their almost complete absence of shrinkage during their use which results in excellent adhesion to concrete.

It will be possible for practitioners to easily determine the appropriate compositions which make it possible to obtain a practically zero shrinkage. The composition of matter which is preferred with a view to approaching an almost zero shrinkage consists of a mixture formed by 75% of styrene and 25% of polystyrene, i this mixture being itself added at a rate of 25% to 75% of polyester.

! The attached diagram shows the apparent removal! measured as a function of the content of the various constituents from 100% of polyester and 0% of a mixture of a composition in accordance with the invention consisting of 75% of styrene and 25% of polystyrene - 5 - * £ as example of the tensile tests of samples consisting of concrete tubes coated with the composition 75% polyester and 25% of the mixture 75% styrene / 25% polys-2 tyrene gives adhesion values in kgf / cm "gives the following values for 6 samples on which were joined using resin, 9 cm ^ pull heads.

., ej Resistance to the- N of -: ~ · 2 1 '^ nhanHIlniL traction hgf / cm 1> 56.7 2> 53.3 k 3> 56.2 4> 51.0 * 5> 40.7 * 6> 56.7

In the case of samples marked with asterisks, the concrete underlying the traction heads fails before the traction head is torn off.

The compositions of the invention find numerous practical applications among which there may be mentioned, in particular repair, sealing and anti-corrosion coating of metallic elements such as metal pipes or concrete elements such as concrete structures.

The product is particularly interesting for its good resistance to repeated shocks and has been used successfully in lock thresholds, as an anchoring element, for sealing dry docks, as covering roads, industrial floors, in sewers and septic tanks etc.

Claims (6)

1. Resin compositions characterized when they contain at least 50% and preferably 65 to 85%, of a commercial polyester resin as well as at least 20% of a mixture consisting of 50 to 85% of mixed styrene with 50 to 20% polystyrene. 2. Compositions according to Claim 1, characterized in that the polyester used has an initial viscosity of 600 cp at 20 ° C., the mixture of styrene and polystyrene is chosen so as to be in the form of a solution of a viscosity of 750 cp at 20 ° C. 3. Compositions according to claim 2, characterized in that the mixture of the three constituents gives a preparation having a viscosity of the order of 670 ° C. 4. Preparations characterized in that they contain a composition according to any one of claims there 3, mixed with sand and gravel "to obtain a resinous concrete. 5. Preparations characterized in that they contain a composition according to any one of claims 1 to 3 in admixture with pigments to obtain a paint or a coating. 6. Application of the compositions according to any one of claims 1 to 3 to repair, sealing and coating of metallic or concrete element.