GB2115312A

GB2115312A - Non-slip surface coating

Info

Publication number: GB2115312A
Application number: GB08204168A
Authority: GB
Inventors: Bryan Francis Shimmin; James Brian Pollard
Original assignee: Reed International Ltd
Current assignee: Reed International Ltd
Priority date: 1982-02-12
Filing date: 1982-02-12
Publication date: 1983-09-07
Also published as: NO830471L; EP0086626A3; EP0086626A2; GB2115312B

Abstract

Rounded quartz sand particles (22) are each enclosed in a hardenable resin skin (23) which is integrated with the skins of adjacent particles and which creates an adhesion of the particles to a primed base (20, 21). A significant fraction of the particles may be remote from the base and only integrated with adjacent particles so that a contoured or embossed effect is created to provide a supplementary non-slip feature. In a process for forming such a surface coating the particles are wetted with a functional liquid, mixed with a binder related to the functional liquid and sprayed. The spraying process is powered by a progressive cavity pump with a selection of particle/resin ratio such that the pump operates under a Sigma effect. <IMAGE>

Description

1 GB2115312A 1

SPECIFICATION

Surface coatings 1 This invention related to surface coatings.

The invention is primarily concerned with non-slip floor coatings and was conceived in that context but it also has application to decorative and prefabricated wall panels and to other decorative surface coatings.

There is a large demand for non-slip coat ings especially in situations where slip can be imposed by adverse conditions despite the exercise of maximum care and when slip can be particularly hazardous. The situations that come to mind are, for example, on the sur faces of off-shore oil platforms where high winds and slippery water and oil soaked sur faces are common, on stairways, elevated walk-ways and on pitching surfaces such as may arise on ships.

There is a well known process for generat ing non-slip coatings. This typically involves blasting a base surface to clean and remove any loose material; treating with a primer to generate adhesion and set up corrosion pro tection; applying a binder by brush, spray, trowel or roller; and finally applying non-slip aggregate or particulate material, generally by hand while the binder is tacky.

This is a four stage process. The surface, when inspected closely, shows particles of non-slip material held rather in the manner of acorns in cups, the particles being the acorns and the set or cured binder forming the cups.

This is generally satisfactory. The non-slip material with its irregular shape, is exposed and held to provide a non-slip surface.

However, the hold between the particles and the binder can be broken with harsh use and one way of reducing this risk is to provide a protective sealer or wear coat. However, unless used very uniformly, the sealer can tend to smooth the surface and acts against the non-slip interest. Another deterioration which can arise in this known process, in the absence of a sealer or wear-coat, is fracture of the exposed aggregate which then tends to fill in the cavities between the aggregate and hence smooth the surface. Further, such a surface is difficult to clean and could not be accepted where there is a risk of spillages of toxic material which need to be cleaned op.

Similarly, it cannot be readily cleaned of oil spillages. Thus, in many situations, the use of a sealer becomes essential and the conse quent loss of non-slip quality must be ac cepted.

The present invention aims to reduce the above stated disadvantages significantly and at the same time offer a process of applying a non-slip coating more conveniently and at a much accelerated rate.

The invention resides in a process of mak ing a product having a non-slip surface corn- 130 prising the steps of:

(a) taking a non-slip particulate material and wetting and mixing it with a binder base to create a flowable composition which when applied as a film is hardenable with time, and (b) spraying the composition with a progressive cavity pump on to a prepared surface so that the particles of the non-slip material are caused to engage both with the prepared surface and adjoint particles through the medium of a skin which hardens with time and which, on the"surface of product, closely follows the outline of the surface exposed particles of the non-slip material.

The invention will now be illustrated with reference to the accompanying drawings in which:

Figure 1 shows in section the structure of a known non-slip surface; Figure 1A shows the structure of Fig. 1 treated with a sealer, where the sealer has been applied excessively; Figure 18 shows the structure of Fig. 1 which has not been treated with a sealer but has been subject to wear; Figure 2 shows, in section, the structure of a non-slip surface according to the invention, and Figure 3 shows, diagrammatically, an appa- ratus suitable for manufacturing the surface shown in Fig. 2.

In Fig. 1 a base 10, which has been blasted to clean it and remove any loose areas, is given a primer coat 11, which may have a sealing and anticorrosive character relative to the base and provide a key for other materials to be applied to the base.

The primer coat, when dry, is covered by brush, spray, trowel or roller with a varnish layer 12. Non-slip particles 13 to 17, such as crushed granite, are then applied to the varnish whilst soft. The varnish hardens and holds the particles in place to give a non-slip surface. Particles 13, 15 and 17 are keyed securely but particles 14 and 16 have little more than face adhesion. With heavy use, particles 14 and 16 will become dislodged and the tips of the keyed particles 13, 15 and 17 will tend to fracture. This is illustrated in Fig. 1 B. The particles 14 and 16 are missing and smaller particles 18 have become lodged in crevices and cavities. Thus a lot of the nonslip quality has been lost and the particles 18 tend to hold and bind with any substances dropped on the surface and provide a---dirtysurface.

To avoid the situation as shown in Fig. 1 B it is customary to provide a sealer coat 19 as shown in Fig. 1 A. This has the merit of covering all the non-slip particles so that particles 14 and 16 are retained and avoids the creation of a dirty surface. It has the demerit of destroying a significant part of non-slip quality inherent in the non- slip particles as it flows and fills cavities and crevices, particu- 2 GB2115312A 2 larly where too much is applied, and it is a further process step which delays completion of the product.

In the arrangement of Fig. 2, a base 20 and primer 21 is shown, but the particles 22 now have a binder skin 23, which approximately follows (with only a slight degree of rounding or smoothing) the profile of the particles. The skin 23 binds particle to particle and particles to base. In addition the particles 22 can stack one on the other (see, for example, particle 22a on particle 22b) and a further contour or emboss is added which aids the non-slip quality.

Whilst the skin 23 masks some of the 80 roughness of the particles it does not mask to the same extent as would the application of a sealer (as in Fig. 1 A) since there is no possi bility of excess binder to---fill-the surface.

Any masking that does arise (and hence any loss of non-slip quality) is made good by the further contouring that arises with the stack ing of the particles.

It is seen that the skin 23 prevents loss of non-slip particles from the surface and pre sents fragmentation of the particles. Thus a clear advantage is achieved relative to Fig.

1 B. The advantage relative to Fig. 1 A has been referred to.

A process and apparatus for manufacturing 95 a product like that shown in Fig. 2 is now described with reference to Fig. 3.

The apparatus of Fig. 3 comprises a particu late material hopper 30 and a resin reservoir 31. The hopper and reservoir feed to a mixing chamber 32 having a rotary blade mixer 32a.

The base of the chamber 32 has a slide gate 33 to allow the mixed contents of chamber 32 to fall into a feed chamber 34 which has, in its lower regions, a screw feeder 35.

The feeder 35 feeds mixed material to a progressive cavity pump 37 (sometimes re ferred to as a---MONO-pump) via a conduit 36. The pump 37 discharges to a pressurised line 38. The line 36 has an associated air line 39 and nozzle 40 so that non-slip product fed along line 38 can be sprayed on to a prepared surface, such as base 20 and primer 21 of Fig. 2.

The pump 37 is driven by a motor 41 115 through a variable gear box 42.

The apparatus of Fig. 3 is very similar to known apparatus for spraying plaster to gen eral relief surfaces but is modified to have a stainless-steel rotor and solvent resistant syn thetic rubber stator.

A typical process in accordance with the invention is as follows: coarse pigmented rounded quartz sand (of two differing pigmen- tations) is wetted with a liquid epoxy or urethane catalyst and supplied to the hopper 30. A urethane or epoxy binder is supplied to the reservoir 31. Measured amounts of wetted sand and binder are supplied to the mixing chamber 32 and the mixer 32a started to provide a flowable compositin of sand and catalysed binder adhering to the sand. When mixing is complete the gate 33 is opened and the composition passes to the feeder 35, pump 37 and then to spray nozzle 40.

The complete process involving blasting, priming and spraying may typically take two days in which time a very large area can be treated.

The particles preferably lie predominantly in the grade of 0.1 mm to 2 mm and especially in the grade 0. 15 mm to 1. 5 mm.

A specific formulation for carrying out the invention will now be described:- Desmophen 800 (85% solids) Desmophen 1700 (70% solids) China Clay 10% Bentone 38 Sand Xylene Desmodur N (75% solids) 100 25 900 40 396 Polyurethane resin and polyester curing agent dissolved in ethyl glycol acetate, supplied by Bayer, Germany.

The invention has application to providing non-slip surfaces on steel, concrete, wood, stone, etc. and on firm painted surfaces. It may also be used on wall areas, particularly for exteriors.

Thick coatings can be applied and overcoatings are practical. Various grades, colours, sizes and types of aggregates can be applied separately or together to give decorative effects.

The invention is based on the remarkable discovery that the pump 37 can handle such abrasive material as quartz sand in resin at high operating loading without excessive wear on the pump. In investigating this phenomena it is believed that the invention exploits the known Sigma or wall effect. This effect shows that if a mixture of solids and liquids is compressed in a tube then the solid tends to move away from the wall of the tube. In the invention the moving cavity in the pump between stator and rotor can be considered as a highly distorted tube but nevertheless such that the mixture of sand and resin is subjected to the Sigma or wall effect and the resin goes to the surfaces of rotor and stator and there provides a protective lubricating surface. This effect is aided by having rounded, nodular, spheroidal and/or ovoid particles present which are relatively large compared to clearances through which the composition is passing.

Claims

CLAIMS 1. A process for making a product having a non-slip surface comprising the steps of:

1 Y e 1 1 3 GB2115312A 3 (a) taking a non-slip particulate material of rounded shape and wetting and mixing it with a binder base to create a flowable composition which is hardenable with time when applied 5 as a film; and (b) spraying the composition with a progressive cavity pump on to a prepared surface so that the particles of the non-slip materials are caused to engage both with the prepared surface and with adjacent particles through the medium of a skin on the particles which hardens with time and which, on the surface of the product, closely follows the outline to the surface exposed particles of non-slip ma- terial.

2. A process according to Claim 1 in which the particles are of rounded quartz sand in the grade range of 0. 15 mm to 1. 5 mm.

3. A process according to Claims 1 or 2 in which a fraction of the particles engage only with adjacent particles and not with the base so that a contour or emboss is set up.

4. A process according to Claims 1, 2 or 3 in which the particulate material is of two or more visually differing materials and the skin is transparent so that a decorative non-slip surface is obtained.

5. A non-slip product comprising a base (20, 21) having thereon non-slip particulate material, the particles (22) thereof being enclosed by a set skin (23) which is integrated with the skins of adjacent particles and which has created an adhesion of the particles with the base.

6. A textured decorative product comprising a wall having thereon abrasive particulate material, the particles (22) thereof being enclosed by a set skin (23) which is integrated with the skins of adjacent particles and which has created an adhesion of the particles with the wall.

Printed for Her Majesty's Stationery Office by Burgess Et Son (Abingdon) Ltd-1 983. Published at The Patent Office, 25 Southampton Buildings, London, WC2A l AY, from which copies may be obtained.