GB2192813A

GB2192813A - Surface coloured building products

Info

Publication number: GB2192813A
Application number: GB08717215A
Authority: GB
Inventors: Christopher Anthony Lee; Stuart Beverley Morton
Original assignee: Redland Bricks Ltd
Current assignee: Redland Bricks Ltd
Priority date: 1986-07-21
Filing date: 1987-07-21
Publication date: 1988-01-27
Anticipated expiration: 2007-07-21
Also published as: GB8617767D0; GB8717215D0; GB2192813B

Abstract

The invention relates to the treatment of porous building products to produce a surface coloured product, such as bricks, tiles, flagstones and similar products used for external building applications. The method of treating the products comprises heating the building product to a temperature above ambient temperature and treating the surface of the product with a heated aqueous dispersion of pigment by immersing the product or spraying it and finally drying the treated product. The most common use of such treatments is to provide a new product which has the appearance of a reclaimed building product, which are in great demand in building applications, but which has the properties of a new product.

Description

SPECIFICATION Surface coloured building products The invention relates to the treatment of porous building products to produce a surface coloured product and is especially, but not exclusively, applicable to the treatment of bricks, roofing tiles, flagstones, paviours and similar products used for external building applications. The products may be made from clay, concrete or other suitable material.

Reclaimed building products, of the type taken from walls, chimney stacks and sections which have been whitewashed, used for external building applications have great aesthetic appeal when used alone or mixed with new products in a building structure such as a brick wall. The reclaimed products give the structure a rustic appearance which makes them a highly desirable commodity for the architect and consumer alike.

The problem with such reclaimed products is that they cannot be quality assured by the supplier.

Merely painting the surface of a new product by usual methods to simulate a reclaimed one will not duplicate the effects of many years weathering and occasional repainting that a reclaimed product will have been subjected to and will not produce a surface colouring that is frost and weather resistant.

The invention provides a method of treating a porous building product to produce a surface coloured product comprising the steps of obtaining a porous building product at above ambient temperature, treating said product with an aqueous dispersion of pigment and drying said product.

We have found that new building products can be matched to reclaimed ones by the application to new building products of a surface treatment consisting of applying an aqueous dispersion of pigment to the surface of a heated building product.

The treatment is preferably applied by spraying said heated building product with a heated aqueous dispersion of pigment or by immersing the product in the heated aqueous dispersion of pigment.

The heated aqueous dispersion of pigment is preferably in the form of a dilute mixture of water and emulsion paint. The emulsion paint is preferably of the type made by Permoglaze under the trade name Permoglaze Pammastic Vinyl Matt.

It is preferred that the building product should be treated after curing or firing and once the required temperature is reached.

A preferred embodiment of the invention will now be described by way of example, with reference to the accompanying drawings.

Figure 1 shows a schematic view of simple apparatus suitable for carrying out the method of treating building products by immersion.

Figure 2 shows a schematic view of simple apparatus suitable for carrying out the method of treating building products by spraying.

Referring first to Figure 1. The apparatus comprises a kiln or curing chamber 4, conveying means 6, a solution bath 8 containing an aqueous dispersion of pigment 10, a dryer 12, stacking means 14 and packing means 16.

Building products 2 at above ambient temperature and preferably "hand-hot" are transported from the kiln 4 to the solution bath 8 by the conveyor 6. The building products 2 are then partially or wholly immersed for a short time in the aqueous dispersion of pigment 10 which is heated to a temperature between 40 c and 85 c during the immersion process.

The building products 2 are then conveyed to the dryer 12 where said products 2 are dryed; said products 2 are then conveyed to the stacking means and are finally conveyed to the packing means 16.

Prior to immersion in the aqueous dispersion of pigment 10, the products 2 are preferably at a temperature between 40 c and 85"c. The aqueous dispersion of pigment 10 should preferably be allowed to stand for a minimum of two hours prior to any product immersion to allow de-aeration of the aqueous dispersion and so minimise surface defects in the finished product.

In a preferred method a heated building product 2 having substantially horizontal and substantially vertical surfaces was immersed in a heated dilute mixture 10 of emulsion paint and water for a minimum of 15 seconds allowing air to be expelled from pores in the product 2 and allowing the coloured solution 10 to penetrate several millimetres into the surfaces of the product 2.

The building product 2 was immersed in a substantially horizontal manner to minimise "runs" in the treatment caused by overflow from the horizontal surfaces of the product 2.

The term heated as used above means at a temperature between 40 c and 85 c in the example described. However, the temperature of the products 2 to be coated and the solution 10 in which the products 2 are immersed will be chosen to avoid any deleterious effects on the solution 10 and the coated product 2.

The term emulsion paint as used herein means a water-thinnable paint made from a pigmented emmulsion or dispersion of a resin in water; e.g. Permoglaze Pammastic Vinyl Matt.

The term dilute as used above means a mixture of water thinnable emulsion paint and water preferably in the range 1:1 to 1:3 parts respectively.

The novel surface treatment provides a coloured surface to the building product 2 which simulates reclaimed products and which retains its colour with weathering.

It is within the scope of the present inven tion to allow for surface heating of a cold building product before treatment by the method described.

It is also within the scope of the present invention to allow for partial immersion of the building product 2 in the solution to produce building products 2 which are coloured on one or more surfaces only.

The colouring of the pigment or paint may be chosen to produce surface coloured products to order and such products couid be used, for example in the building of decorative wall murals, or walls of one colour.

An alternative method of applying the aqueous dispersion of pigment 10 to the heated building product 2 is by spraying. Figure 2 shows suitable apparatus for carrying out this method, wherein the solution bath 8 of Figure 1 has been replaced by spraying chamber 18.

When spraying is used to apply solution 10, the preferred maximum temperature of the solution 10 is 70"c. At temperatures above this the solution 10 bonds prior to application and cannot penetrate the surface of the product 2.

However, it is noted that the temperature ranges for both the spraying and immersion methods will vary according to the type of paint solution 10 being used, the method being used and the relative temperature and composition of the building product 2.

The advantages of this method over immersion, lie in the fact that the spray can be controlled if necessary to cover certain portions of the product only, resulting in paint savings and shorter drying times.

It is also within the scope of the present invention to allow for application of the aqueous dispersion of pigment to the heated building product by methods other than immersion and spraying and to allow for several such applications by immersion or otherwise.

Claims

1. A method of treating a porous building product to produce a surface coloured product comprising the steps of obtaining a porous building product at above ambient temperature, treating said product with an aqueous dispersion of pigment which has been heated and drying said product.

2. A method of treating a porous building product as claimed in claim 1 in which the porous building product is heated before treatment.

3. A method of treating a porous building product as claimed jn claim 1 or 2 in which the porous building product is at a temperature between 40 c and 85 c during treatment.

4. A method of treating a porous building product as claimed in any one of the preceding claims in which the aqueous dispersion of pigment is at a temperature between 40 c and 850c during treatment.

5. A method of treating a porous building product as claimed in claim 4 in which the aqueous dispersion of pigment is at a temperature between 40"e and 70 c during treatment.

6. A method of treating a porous building product as claimed in any one of the preceding claims in which the aqueous dispersion of pigment comprises a mixture of emulsion paint and water.

7. A method as claimed in claim 6 in which the ratio of emulsion paint to water in the mixture is in the range 1:1 to 1:3.

8. A method of treating a porous building product as claimed in any one of the preceding claims in which the product is sprayed with the aqueous dispersion of pigment.

9. A method of treating a porous building product as claimed in any one of claims 1 to 7 in which the product is immersed in the aqueous dispersion of pigment.

10. A method of treating a porous building product as claimed in any one of claims 1-7 in which the porous building product is only partially immersed in the aqueous dispersion of pigment.

11. A method of treating a porous building product so as to produce a surface coloured product substantially as hereinbefore described.

12. A surface coloured product when produced by the method as claimed in any one of the preceding claims.

13. An apparatus as hereinbefore described for use in the method of any one of claims 1 to 10.