GB2315494A - Polymer wax coating - Google Patents

Abstract

A wax coating comprising an anionic polymer, at least one wax emulsion and water. The wax coating does not utilise hazardous chemical solvents and can be used on all types of wooden surfaces, particularly pine.

Description

POLYMER WAX COATING The present invention relates to a new and improved polymer wax coating.

A variety of products have been used in the past to polish surfaces such as wooden furniture and working surfaces. Bees wax was one ofthe first products used in an attempt to form a protective coating against dirt and wear and also to impart a lustrous, glossy finish. French polish was also extensively used and since then several polymer based coatings have been marketed, for example nitrocellulose and acrylic lacquers.

The reason for using and developing such polishes has stemmed from the need to obtain a glossy wax-like finish whilst maintaining a durable coating which protects the surface to which the coating is applied.

Generally speaking, wax coatings have consisted of solvent-based blends of natural and synthetic waxes, wherein waxes of various melt points are dissolved in aromatic solvents, the mixture then sets upon cooling, forming a wax paste to be used as a coating on various surfaces.

There have been considerable problems associated with the wax products of the above mentioned type. Typically, when solvent-based products are applied to a surface, for example wood, the solvent evaporates leaving behind a wax coating which is susceptible to marking, spotting or melting by hot materials such as cups containing hot liquids. Also, the applied wax coating is often very thin and several coats are required to be used in order to achieve the desired cover or finish.

Further to this, the use of certain chemical solvents in solvent based wax compositions have proven to be dangerous due to the hazardous nature of the solvents.

For example, toluene has been used as a solvent-base to prepare wax coatings. Toluene is classified as harmful and consequently may be banned from use in many countries. It can therefore no longer be tolerated in a wax coating due to harmful emissions during use, particularly as such polishes are generally used in the home with no protective measures usually being taken.

Traditionally, lacquer finishes have been used to coat wood. This method comprises a labourious multi-step procedure involving an initial step of staining the wood, the pre-treatment step followed by several coats of lacquer, which results in a glossy finish.

Much effort has also been made in treating wood surfaces, particularly pine, to create an "antique" effect. This involves the application of several coats of lacquer or wax to achieve the desired "antique" effect, which is essentially similar to the appearance of old fashioned bees wax polished wood furniture or surfaces.

The present invention has been made from a consideration of the above mentioned problems.

It is an object of the present invention to provide a wax coating which does not utilise hazardous chemical solvents and which can be used on all types of wooden surfaces, particularly pine.

It is a further object of the present invention to provide a wax coating which is less susceptible to marking, water spotting and melting than wax coatings presently in use.

It is a further object of the present invention to provide a wax coating which requires the application of only one or two coatings to produce a wax coating which requires the application of only one or two coats to produce the desired colour or finish, with no requirement to pretreat the surface prior to application. Particularly, it is an object ofthe present invention to provide a wax coating which can produce an "antique" look when applied to a wood surface such as pine.

According to the present invention there is provided a wax coating comprising an anionic polymer, at least one wax emulsion and water.

The use of water as the solvent base means that the wax coating of the present invention is less hazardous than wax coatings utilising chemical solvents as a component in their manufacture.

According to a second aspect of the present invention there is provided a method of applying a wax coating to a surface, the said coating comprising an anionic polymer, at least one wax emulsion and water.

The wax coating may additionally comprise colourants which stain the surface to which the coating is applied.

The use of colourants in the composition is advantageous as it results in staining ofthe surface, in particular a surface such as wood, together with providing a protective film on the surface and imparting a glossy finish without the need for a multi-step procedure to achieve the same effect, as required by the prior art.

Typically, the present invention utilises pigment dispersions to provide colour to the composition of the present invention. In the past, dye solutions have been used to provide the same effect. Pigment dispersions provide a stronger colour strength to the emulsion ofthe present invention than the prior art dye solutions and also offer better light fastness.

For example, the wax coating may comprise one or more of the following colour pigment components:- Red 184, yellow 83, red 9, black 7, green 7. These pigments may be obtained commercially, one of the sources being the "Hosta fine" (Brand name) range of pigment preparations marketed by Hoechst (Trade Mark).

The wax coating does not necessarily contain additional colourants. It can be used as a clear coating which allows the natural surface characteristics of the wood to be appreciated.

The anionic polymer component used in the present invention preferably comprises 0-40% by weight of the total composition. More preferably, it comprises 5-25% by weight ofthe total composition. Most preferably, it comprises 10-20% by weight of the total composition.

Suitable anionic polymers include polymers and their derivatives being selected from the following: Acrylic copolymers, for example, acrylate/methacrylate esters with fine particle dispersion. The anionic polymer component is preferably formulated as an emulsion.

The anionic polymer component is particularly important. It contributes to the film build characteristics ofthe present invention. Consequently, the applied film imparts a higher film thickness than traditional waxes and reduces the need for the application of two or more coats in order to achieve the desired protective effect of the coating.

Furthermore, the polymer component affects the drying time of the applied film.

Typically, the drying time of a coating applied in accordance with the present invention is between 10-30 minutes. This time period, when compared with the time requirement of methods such as French polishing of wooden surfaces, which is extremely time consuming and labourious, is a considerable advantage of the coating and method of the present invention.

The choice of the polymer component in the wax coating is particularly important as it influences how much of the coating is absorbed by the surface onto which it is applied. In the past, several coats of wax/lacquer have been required due to the porous nature of surfaces such as pine. The first coat is usually absorbed by the porous surface and further coats are required to impart a protective film and glossy finish. Quite often it is necessary to pretreat the wood so as to provide a less porous surface to which a wax coating may be applied.

The wax coating of the present invention is absorbed to a less degree by porous surfaces, such as pine. The choice of polymer and its interaction with the other components of the coating of the present invention contributes to the decreased absorbency of the coating by a porous surface thus resulting in the requirement of only one or two applications of the wax coating to a surface.

The wax emulsion used in the present invention is preferably non-ionic.

A suitable wax emulsion to be used in the present invention includes a polymeric wax emulsion, preferably a polyethylene wax emulsion.

Further suitable non-ionic wax emulsions comprise waxes with a melt point in the range of 50-150"C. If the melt point is too high the coating will set and form a hard composition. Preferably, the non-ionic wax emulsion comprises wax with a melt point in the range 70-140"C.

A preferred non-ionic wax emulsion used in the present invention is a "Montan" type of wax emulsion. This comprises a non-ionic emulsion including one or more waxes with a melt point in the range of 79-85"C and the maximum particle size being 1 micron.

Preferably, the wax emulsion component may consist of one or more of the above mentioned suitable components. Preferably, it comprises 0-40% by weight of the total composition. More preferably, it comprises 10-20% by weight of the total composition.

Most preferably, it comprises 10-16% by weight of the total composition.

The primary function of the wax coating system is to provide a protective film together with a glossy finish to the surface. The ratio of polymer to wax component contributes to the film build and drying time characteristics. The coating may also include other components commonly used in wax coatings. Plasticisers, humectants, defoamers, gelling agents, preservatives, surfactants and emulsifiers may be incorporated in the usual manner.

The choice of plasticiser also appears to affect the unique characteristics of the wax coating of the present invention. Phthalates appear to enhance the characteristics of the wax coating and the most preferred plasticisers is Butylbenzylphthalate.

Examples of polymer wax coatings include liquids and the viscosity may be altered so as to form a stiff paste. The coating may be applied by brush, spray gun or cloth.

The invention will now be further illustrated by way of the following examples.

Example 1 Polymer wax coatings were formulated as follows: Component Paste Liquid Spray % by weight % bv weight %bvweight Acrylic copolymer 16.6 17.1 14.54 Butyl benzyl phthalate 2.6 2.6 2.21 Monopropylene glycol 7.0 7.0 5.95 Anti-foaming agent 0.2 0.2 0.17 Polyethylene wax emulsion 12.4 12.4 10.54 Montan wax emulsion 2.7 2.7 2.30 Preservative 0.5 0.5 0.050 Viscosity-modifier 0.5 Non-ionic surfactant Colourants: Red 184 0.02 0.02 0.02 Yellow 83 0.02 0.02 0.02 Black 7 0.02 0.02 0.02 Red 9 Green 7 Water 57.44 57.44 63.75 Ratio and choice of pigments is dependant upon the required shade.

Example 1 was made as follows: Charge mixing vessel with the copolymer, and add each item in order slowly during agitation, care must be taken to avoid aeration. Pigment flocculation can occur if the correct mixing procedure is not followed. The paste formulation must be filled into the containers within 3 hours of manufacture.

In comparison with a traditional wax, the above formulation has displayed increased film thickness, reduced drying time, substantially less marking with increased resistance to water and common soiling and increased resistance to heat, resulting in a much more durable coating.

The following experimental results illustrate the superior performance of the wax coating of the present invention as compared with two presently known wax coatings.

The components of the two known wax coatings are as follows: Fiddies (Trade Mark) Stripped Pine durable wood finish comprises aliphatic Solvent containing 12% aromatic solvent, this solvent mixture commonly known as Rubber Solvent comprises 74% of the wood finish. The remainder of the wood finish comprises waxes and dyestuffs.

Briwax Antique Mahogany (Trade Mark) comprises 50-75% toluene and the remainder of the coating comprises waxes and dyestuffs.

Method of Testing Each of the wood finishes listed above were applied onto pine covered hardboard (190mm x 210mm) via the use of a soft cloth. A second coat was then applied 30 minutes after the first coat, by the same method. This process was then repeated for addition of a third coat. In each case the dry and wet mass of the three coats was measured to determine the coverage potential of each product.

A number of dry film properties were then tested for each product: Abrasion Resistance The abrasion resistance was tested using a pad (100mm x 50mm) of synthetic wire wool grade 0000 extra fine. The pad of wire wool was placed onto the dry coating surface, a 500 gram mass was then placed on top of the wire wool, this was then dragged across the surface of the coating. This constituted 1 "rub", each coated board was then subjected to 300 such rubs, after which observations were then made about the resultant condition of the coating.

Chemical Resistance A number of materials namely, water, bleach, solvent based cleaner, coffee, methanol, milk and upholstery cleaner were placed on the dry coating's surface. Each spot of liquid was left on the coating's surface for 60 minutes after which the liquids were washed off with water and dried. The coating's surface was then inspected for any degradation.

Ring Resistance A mug containing boiling water was placed on the coating's surface for 60 minutes, after which the mug was removed and the coating's surface inspected for any marks.

This test was then repeated, however, in this case the coating surface was dampened with a sponge, to provide a film of water on the surface of the coating.

Temperature/Water Resistance A coated board was inclined at 45 degrees, then 1 litre of boiling water was poured down the beard, after which the board was inspected to check for the integrity of the film. This test was then carried out for all three products.

Results Ease of Application The wax ofthe present invention was found to be the most "user friendly" wood finish. The application of pine wax was relatively easy and produced a very good and even final film.

Problems were encountered when applying the Fiddies product, especially when applying the second and third coats as lumps of the coating occurred on the surface (which could be rubbed out) thereby causing an uneven colour and finish. This was a result of the fact that the Fiddies product was in a solid form and requires very careful application in order to spread an even film, when compared to the lower viscosity Briggs pine wax paste which flowed out very easily.

The Briwax product also gave rise to similar problems, however, these were not as severe as encountered in the Fiddies product as the Briwax product was slightly more paste like.

Coverage Fiddies Stripped Pine Durable Wood Finish = 20. 10g/m2 Briwax = 14.51g/m2 James Briggs Pine Wax = 30.83g/m2 The Briwax product shows the least amount of material required to cover a square metre of substrate. However, the highest value as shown by Briggs pine wax indicates the relative ease of application when compared to the other two products.

Abrasion Resistance The James Briggs pine wax showed vastly superior abrasion resistance than the other two products. The board showed an actual increase in gloss as the test had simply "buffed up" the pine wax coating.

The other two products showed a clear discolouration as a significant amount of material was abraded from the surface of the board. In fact small patches of bare wood were exposed on the Fiddies test board.

These results are due to the fact that both the Fiddies and Briwax products are simply coloured waxes which have limited film integrity. The Briggs pine wax actually seals the wood as well as providing a coloured wax finish as it contains a polymer film former.

Chemical Resistance

FIDDlES BRIGGS BRIWAX Water Fair Excellent Poor Bleach Poor Poor Poor Solvent Cleaner Poor Good Very Poor Coffee Fair Fair Fair Methanol Fair Good Fair Milk Fair Excellent Poor Upholstery Cleaner Poor Excellent Poor It can be seen that Briggs pine wax has a significantly better chemical resistance than the other two products. This is due to the polymeric film former within Briggs pine wax which imparts a better chemical resistance than the simple waxes which make up the Fiddies and Briwax products.

Ring Resistance None of the three products exhibited white rings in either the dry or wet ring resistance test.

However, the Fiddies and Briwax films did show circles of high gloss where the mugs had rested. This was due to the waxes being heated by the mugs and flowing out to form a smooth surface. Also the wet ring resistance test results showed that water discoloured the surface of both the Fiddies and Briwax products.

The Briggs pine wax was unaffected by both the dry and wet ring resistance tests.

The surface suffered no discolouration in either test and was not affected by contact with water. This improved resistance is due once again to the polymer film former providing a stable heat resistant film.

Temperature/Water Resistance Both the Fiddies and Briwax products suffered severe discolouration as the boiling water melted the waxes contained in both and simply washed them of the board to leave the actual surface of the wood substrate exposed.

The Briggs pine wax was unaffected as a result of the polymer film former protecting the pigment and waxes contained in the formulation.

Conclusion The Briggs pine wax was certainly the easiest to apply and therefore gave the most attractive finish, however, this resulted in it having the largest wet film mass per square metre. However, it must be realised that in order for the Briwax and Fiddies products to fulfil the same role, a primer/sealant would be required which would increase the coverage figure significantly.

The Briggs pine wax was clearly the most robust wood finish as a result of the polymer film former. The polymer sealed the wood substrate and protected the wax and pigmentation from chemical attack and heat.

The Fiddies and Briwax products simply contained a pigment and waxes, therefore exposure to chemicals and heat resulted in the removal each of the products from the wood surface.

The above invention is not restricted to the above described embodiments and many variations and modifications can be made.

Claims (19)

Claims

1. A wax coating comprising an anionic polymer, at least one wax emulsion and water.

2. A wax coating according to claim 1, wherein the anionic polymer component comprises up to 40% by weight of the total composition

3. A wax coating according to claim 2, wherein the anionic polymer component comprises 5-25% by weight of the total composition.

4. A wax coating according to claim 3, wherein the anionic polymer component comprises 10-20% by weight of the total composition.

5. A wax coating according to preceding claim wherein the anionic polymer component comprises acrylic copolymer.

6. A wax coating according to claim 5, wherein the acrylic copolymer comprises acrylate/methacrylate esters.

7. A wax coating according to any of the preceding claims, wherein the anionic polymer component is an emulsion.

8. A wax coating according to any preceding claim, wherein the wax emulsion is nonionic.

9. A wax coating according to any preceding claim, wherein the wax emulsion is polymeric.

10. A wax coating according to any preceding claim, wherein the wax emulsion is a polyethylene wax emulsion.

11. A wax coating according to any preceding claim, wherein the wax emulsion comprises at least one wax with a melt point in the range 50-150"C.

12. A wax coating according to claim 11, wherein the at least one wax has a melt point in the range 70-1 400C.

13. A wax coating according to claim 12, wherein the wax emulsion comprises at least one wax with a melt point in the range 79-85"C and the maximum particle size is 1 micron.

14. A wax coating according to any preceding claim, wherein the wax emulsion comprises up to 40% by weight of the total composition.

15. A wax coating according to any preceding claim, wherein the wax emulsion comprises 10-20% by weight of the total composition.

16. A wax coating according to any preceding claim, wherein the wax emulsion comprises 10-16% by weight ofthe total composition.

17. A wax coating as claimed in any preceding claim, additionally comprising colourants which stain the surface to which the coating is applied.

18. A method of applying a wax coating to a surface, the said coating comprising an anionic polymer, at least one wax emulsion and water.

19. A wax coating in accordance with the invention as described with reference to the example.