GB2338959A

GB2338959A - Abrasion resistant floor coating composition

Info

Publication number: GB2338959A
Application number: GB9814492A
Authority: GB
Inventors: Martin Hutchinson; Stuart Edward Fores
Original assignee: E Wood Ltd
Current assignee: E Wood Ltd
Priority date: 1998-07-03
Filing date: 1998-07-03
Publication date: 2000-01-12
Also published as: GB9814492D0

Description

2338959

DESCRIPTION OF INVENTION

Title: "Floor Coatings" THIS INVENTION relates to floor coatings and is of particular, (but not exclusive), utility in relation to floor coatings for industrial premises which are subject to heavy wear or abrasion.

At present, industrial floors are protected with a wide variety of coatings ranging from simple thin film paints which can be applied directly to the floor surface and which will provide a limited amount of protection as well as dust proofing the surface, to heavy-duty screeds and polymer mixtures which can be applied at thicknesses in excess of 6mm and which will provide long term protection to the floor in question.

Materials used in floor protection coatings include simple solvent-based resin coatings, two component epoxy coatings, acrylic coatings, methacrylates chlorinated rubbers, polyesters, twin component polyurethanes and moisture cured polyurethanes.

More traditional materials include polymer modified screeds and simple, fastsetting concrete screeds which can also be used to refurbish wom and damaged floor areas.

2 In the early days of floor coating technology, simple solvent soluble resins were used and for many years, the solutions involved provided minimal protection to the floor areas in question.

Over the last 20-30 years, twin pack epoxy and twin pack polyurethane products have become much more popular and today these two resin types dominate the floor coating market particularly in the UK.

All resin based coatings and compositions will provide a reasonable degree of protection to concrete floors but in turn, all such materials suffer from the same defects as the original concrete, over which they are normally applied, in that eventually the coatings will wear and deteriorate when subjected to heavy abrasion and heavy duty conditions.

Generally speaking, where heavy duty conditions exist, thicker coatings and thicker compositions are used to provide a higher degree of protection based on the thickness of the material supplied.

Traditionally, thin film coatings applied at thicknesses up to say 250 microns have not been considered for the long term protection of floor surfaces due to the fact that such a relatively thin film of material has a limited life, particularly where excessive abrasion and wear occurs on the floor in question.

Typically, a concrete floor coated with a twin component epoxy coating would have to be recoated within one to two years of application if the floor in question was subject to heavy traffic conditions.

Conventional floor coatings rely on the toughness and the durability of the resin used within a particular formulation and where fillers are used, they are 3 selected to provide general properties such as ease of application, speed of drying and, of course, to provide a desired final appearance and colour to the floor in question.

It is an object of the present invention to provide an improved wear and abrasion-resistant floor coating for the long term protection of floor surfaces in a wide range of industrial environments.

According to the invention there is provided a coating suitable for floors, comprising a binder and an abrasion resistant filler comprising silica and silicon carbide.

In preferred embodiments of the invention, there is provided a coating composition which comprises a liquid epoxy resin, an amine curing agent and a combination of silica and silicon carbide fillers which can act to provide a highly durable coating.

In the most preferred embodiments of the invention, the filler comprises around 75% silica and 25% silicon carbide.

DESCRIPTION OF TABLES

In the accompanying tables:- Table I illustrates, for purposes of comparison, the performance of floor coating compositions not in accordance with the invention, 4 Table 2 is a table, similar to Table 1, but illustrating the performance of further floor coating compositions in accordance with the invention but not in accordance with the more preferred embodiments, Table 3 is a similar table illustrating the performance of a floor coating composition in accordance with the invention, Table 4 illustrates the variation of performance using different curing agents in a composition in accordance with the invention, Tables 5 and 6 illustrate, for purposes of comparison, the respective performances of different binders with different fillers, and Table 7 illustrates that the filler composition in accordance with the prefer-red embodiment of the invention does not detract from performance in respects other than wear-resi stance.

In all of the examples to be described below with reference to Tables I to 5 and 7, the coating composition comprised a binder in the form of a conventional liquid epoxy resin, such as DER 351 obtainable from Dow Chemicals reacted with a polyamine curing agent. The coating comprised in each case a binder specified in the respective examples.

Abrasion resistance in each case was tested by the Taber Abrasion Resistance Test, the results being shown, in the accompanying tables, in terms of mg loss from the cured coating, per 1000 abrasion cycles utilising CS 17 abrasive wheels.

To provide a comparison with the results obtained in accordance with the invention, Table I illustrates results using, (a) no filler at all, (b) barium sulphate filler, (c) magnesium silicate filler and (d) calcium carbonate filler, in various proportions, set out in the table as percentages by weight of the whole composition. It will be noted that these fillers did not improve the wear resistance of the coating, as compared with the standard resin system without filler and indeed, in some cases, produced reduced abrasion resistance.

Table 2 illustrates the results of a similar test using harder fillers, namely aluminium oxide, silica, and silicon carbide. It will noted that, in these examples, there was a significant improvement in wear resistance, the best improvement being produced by a 30% by weight addition of silicon carbide.

Table 3 illustrates the results obtained using, as fillers, a combination or blend of silica and silicon carbide and shows that, surprisingly, combinations or mixtures of these two materials can produce significantly better results than corresponding amounts of either of these materials alone. The best results obtained and illustrated in Table 3 were obtained using, as 30% by weight of the total coating composition, a filler comprising 75% silica and 25% silicon carbide, (i.e. 22.5% by weight of the total composition of silica and 7.5% by weight of the total composition of silicon carbide).

Table 4 illustrates the results obtained using, with this preferred filler composition, (i.e. 22.5% by weight of the total composition of silica and 7.5% by weight of the total composition of silicon carbide), different curing agents for the epoxy resin. It will be noted from the table that there was some resulting variation in the abrasion resistance of the coating, with cycloaliphatic polyamines producing the best results and aliphatic amidoamines producing the worst, although the difference was not great.

6 Table 5 shows, for comparison, results obtained using, as fillers, (a) barium sulphate, (b) silica and (c) the preferred silica/silicon carbide mixture referred to above, for each of three different epoxy resin binder systems, whilst Table 6 shows corresponding results obtained using other binder systems. Thus, it will be apparent that the use of the preferred filler mixture in accordance with the invention is capable of providing improved results with a wide variety of binders.

Table 7 illustrates the results of a test conducted to establish whether improved results obtained in accordance with the invention as regards wear resistance, were obtained at the cost of other desirable properties of a floor coating, such as strength of adhesion to the base to which the coating is applied, flexibility, hardness and impact resistance. Identical results were obtained regardless of whether barium sulphate or the preferred silica/silicon carbide combination was utilised as a filler, showing that the preferred silica/silicon carbide combination did not detract from these other desirable properties.

Thus, it is possible, using the prefer-red combination of silica and silicon carbide as a filler, to make a dramatic improvement to the abrasion resistance of flooring compositions without adversely affecting other key properties such as adhesion, impact resistance, flexibility, etc.

Claims

7 CLAIMS

1. A coating composition suitable for floors, comprising a binder and a filler comprising silica and silicon carbide.

2. A coating composition suitable for floors, comprising a binder and a filler comprising a blend of silica and silicon carbide in which there is at least 25% silica by weight of the blend and at least 25% silicon carbide by weight of the blend.

3. A coating composition according to claim 2 in which there is at least 50% silica by weight of the blend.

4. A coating composition according to claim 3 in which there is between 60 and 80% silica by weight in the blend.

5. A coating composition according to claim 4 in which said blend comprises 75% by weight silica and 25% by weight of silicon carbide.

6. A coating composition according to any preceding claim, wherein the binder comprises an epoxy resin.

7. A coating composition according to any of claims I to 6 in which said binder comprises a solvent-based two-component aliphatic urethane.

8. A coating composition according to any of claims I to 6 in which said binder comprises a solvent-based, one-component aromatic urethane.

8

9. A coating composition according to any of claims I to 6 in which said binder comprises a solvent-free, two-component aromatic urethane.

10. A coating composition comprising a binder and a filler comprising 25% by weight of silicon carbide and 75% by weight of silica, and in which said filler is present in an amount to constitute up to 30% by weight of the cured coating.

11. A coating composition comprising a water-based or solvent-based epoxy resin with aliphatic polyamine as a curing agent and a filler comprising 25% by weight of silicon carbide and 75% by weight of silica in an amount to constitute up to 30% by weight of the cured coating.

12. A coating composition according to any preceding claim, in which said filler is present in an amount to constitute up to 20% by weight of the cured coating.