Polyethylene powder coatings are used in a wide variety of applications, in particular for coating webs or mats of woven or fibrous material, where the polyethylene can provide some resilience to the structure. One application is the use of such resins as backing for automotive carpets. Typically for such applications, low density polyethylene (eg density 920-940 kg/m3) is used. We have found that excellent results can be obtained using a higher density polyethylene having a high melt index.

Accordingly, in a first aspect the present invention provides a substrate having a surface on which is disposed a sprayed coating comprising a polyethylene resin having a density of from 955 to 975 kg/m3 and a melt index MI2 of from 0.1 to 350 g/lOmin.

The resin is sprayed onto the substrate. Preferably the melt index Mk of the resin is at least 20 g/lOmin, more preferably at least 30 g/lOmin and most preferably at least 40 g/lOmin. Preferred resins may have melt indexes of at least 50 g/lOmin or even at least 100 g/lOmin. The melt index is preferably no greater than 300 g/lOmin, and more preferably no greater than 200 g/lOmin.

In one embodiment, the substrate comprises a web of fibrous or woven material.

We have found that in such cases, the high Mk of the resin results in better penetration of the resin into the fibres of the substrate.

In a preferred embodiment, the substrate is an automotive carpet, with the web onto which the coating has been sprayed comprising a mat of fibres; the resin coating thus formed functions as an underlay for the carpet. In alternative applications the substrate is a cloth such as clothing, or a net such as a mosquito net.

The resin may be a polyethylene homopolymer, or it may be a copolymer of ethylene and another alpha-olefin containing from 3 to 12 carbon atoms. Preferably it is a copolymer of ethylene with butene, methylpentene, hexene and/or octene; the most preferred copolymer is 1-butene.

Preferred catalysts for making the polymer are Ziegler catalysts, although metallocene catalysts may be used. The process is preferably a slurry or solution process.

The polymer may additionally contain the usual stabilizers and processing aids.

Examples of processing aids include fluoropolymers such as polyvinylidene fluoride.

EXAMPLE 1 Hexane, ethylene, hydrogen, 1-butene, trialkylaluminium (30ppm) and a Ziegler- type catalyst such as disclosed in EP 703247 were introduced into a polymerisation reactor and the ethylene was polymerised at 85°C with an average residence time of 1.5 hours. Details of the reaction conditions are given in Table 1 below. The monomodal resin produced in the above reaction was then compounded with calcium stearate into granules, the properties of which are given in Table 2 below.

In this specification the melt index MI2 is measured in accordance with ASTM D- 1238 at 190°C with a load of 2.16 kg. The density is measured in accordance with ISO 1183.

EXAMPLES 2-5 These Examples were prepared in a batch process under similar conditions to those for Example 1, as indicated in Table 1 below.

TABLE 1 EXAMPLE 1 2 3 4 5 Temp (°C) 85 85 85 85 85 Residence time (h) 1.56 1.5 1.5 1.5 1.5 H2/C2 (% mol/mol) 13 25 20 15 22 C4/C2 (% mol/mol) 0 5 7 11 14 TABLE 2 EXAMPLE 1 2 3 4 5 Mix (g/lOmin) 47 280 157 122 306 Density (kg/m3) 968.6 967.7 967.0 961.4 963.8

When sprayed onto the back of a web of fibres such as an automotive carpet, the resins of the invention demonstrate excellent penetration into the fibres. This can be seen in Figures 1 and 2 of the accompanying drawings, which show optical micrographs at l OOx magnification of two resin layers which have been sprayed onto an automotive carpet layer. Figure 1 shows a commercial resin Eltex A3180PN1852 having a density of 957 kg M-3 and an MI2 of 21 dg min'', and Figure 2 shows the resin of Example 1 above. It can be seen that there are many more fibres embedded in the resin layer in Figure 2 (one is indicated by an arrow) than in Figure 1 (the fibres are ringed), demonstrating the improved penetration of the resin of the invention.