LU84516A1 - IMPROVEMENTS IN PROCESSES FOR COATING LAMINATED SURFACES, WITH A VIEW TO MAKING THEM ABRASION RESISTANT - Google Patents

Description

Λ; β r i ί.

·, The present invention relates to ^ per-! procedures to coat sur- | sheet faces in order to make them resistant to | abrasion and relates to a container 5 5 thus produced.

g. A method is known for coating the surfaces of objects, which includes suitable arrangements. · Ν, | jf sistant: to prepare the surface according to current practice, for the reception of a coating of molten metal applied with a spray gun, to spray over this surface a coated with stainless steel or!; r. of molybdenum, in order to establish an intermediate surface,,.,,.

jf continuous diary, waterproof and "microcrenelép", which has prominences and micro-interstices; 15 scopiques and, finally, to apply on the surface an antiacolutinant agent and to sinter or harden the coating, so as to constitute a complete covering, firmly bonded, for the hard plaster sprayed in j metal, establishing thus an outer surface 1 20 resistant to abrasion and antiagalutinante.

This process has not been found to be entirely satisfactory, since it has been found that the abrasion resistant and antiaglutinous outer surface is liable to be damaged and lost Γ; * 25 thus put the penetration of humidity up to the substrate or ferrous bottom, made of cast iron or ...

; mild steel, thereby causing corrosion.

t,] * The disadvantage of using enamelled containers is that it happens that the!. ·: 301 content sticks to the interior surface. The process r | a of enameling is normally applied to rough parts ‘i‘ 1 of cast iron or pressed steel and requires two ij j layers, the application of which requires heating of the container at 800 ° C.

35 Polytetrafluoroethylene (PTFE ^ undergoes | / i y ï 7 t I.,.

I thermal destruction at temperatures above 450 ° C and therefore any application of PTFE should take place after the aluminum for enameling has been applied. Heating the cast iron or mild steel to P00 ° C before the entire object has been covered with a primer results in oxidation of the surface. If the interior surface of the container is not provided with a primer when applying PTFE, oxidation means that good adhesion cannot be obtained. If PTFE is applied to an enamel topcoat, good adhesion is not obtained, and the PTFE coating flakes off quickly. This also applies to the case where PTFE is applied to the base coat. To remedy this, a glassy type frit is applied to the internal base layer; when the PTFE is then applied - which requires a certain amount of heat - better adhesion is obtained; however, the glass-like frit tends to disintegrate under repeated cooling, and the PTFE coating comes off.

The solution to the problem is to- | remove the bottom layer on the inner surface of the container by sanding, in order to expose the bare metal, and then apply the PTFE of | the normal way. This has the disadvantage

• I

î - that the coated plaster may be damaged during the sanding operation. The base layer contains silica, which during shot peening can pose a health risk.

The object of the present invention is to apply a mother or matrix layer to a vitreous enamel base layer and to then apply the coating of P'TFE, which gives excellent quality. I>. · * '3 i s j adherent surface, anti-corrosion and antiagglutinan- I5 te. A steel mother layer has the advantage that if the PTFE surface deteriorates, the mother layer prevents water from reaching the metal. 5 base, which consists of cast iron or stamped mild steel, which rust when they come into contact with water.

I According to the invention, the process which is the subject includes the provisions which consis-i. 10 tent: to be applied to a base substrate, at a sintering temperature of 600 to 700 ° C, a bottom layer of vitreous enamel having, in the finished state, one! surface roughness from 7.5 to 15 microns, pisto- | 1st by flame, on the surface of the base layer, 4 15 a mother layer of stainless steel or of molybdenum i and to allow to cool; spray on the coat; steel, stainless or molybdenum, a resin or water base coat; air dry or oven dry and cool again and finally spray coat a top coat, based on polytetrafluoroethylene (PTFE) or polyhexa - fluoropropylene-tetrafluoroethylene (HFP / TFEÏ and

; '' to be abandoned at a temperature of 200 ° C to 450 ° C

for 20 to 30 minutes.

] '25 The invention will be described below, in; 'referring to the accompanying drawings:: j Figure 1 is an elevational view in s i, i section of a degreased substrate.

Figure 2 is a similar section after the application of a base coat or ceramic primer. mique; Figure 3 is a section similar to that shown in Figure 2, after the application of a coating of stainless steel or molybdenum over the ceramic base layer.

j 1 i i i i l 4 ί * β I-

Figure 4 is a section similar to Figure 3, after applying a coating of PTFE over the coating of stainless steel or molybdenum.

| 5 On a ferrous substrate a, as applied in FIG. 1, a coating is applied. killed by a ceramic bottom layer b of enamel! vitreous (frit !, applied to one or more; "faces of the substrate or the base surface a.

Il 10 The vitreous enamel b (sintered! Has a surface roughness of about 7.5 to 1.5 microns in the finished state, with a sintering temperature of ί 600 ° C to 700 ° C.

A layer of stainless steel or molybdenum c of a thickness of about 0.001 - 0.002 inch (0.025) is applied to the vi-15 treux b (frit!) Enamel coating by flame spraying. - 0.050 mm = 25 - 50 microns), which is allowed to cool.

20 The layer of stainless steel or molybdenum forms an impermeable "micro-crenellated" intermediate surface with prominences and interstices:. microscopic, called to receive a coating of base coat (not shown! resin-based or water-based, applied to the surface of stainless steel-I ·, dable c, coating which is left to dry air or dry in the oven at 120 ° - 150 ° C and allow to cool.

: j We spray on the base layer at j 30 resin or water base a finishing layer d to | based on PTFE or HFP / TFE, · leave at a temperature of 200 ° C - 450 ° C for 20 to 30 minutes.

’· *! j The impregnated layer of PTFE or HFP / TFE, j does the stainless steel layer c and produces excellent adhesion and a hard anti-caking surface fl 1 'U- 1 ► 5 stain resistant scratches or abrasion and I ensures a longer life for the object.

j Creation of the stainless steel layer

! dable c impregnated with a coating d of PTFE or HFP / TFE

5 applied over a protective layer of glassy enamel j (frit) prevents water from being able to - to | favor of deterioration due to abrasion or jj- [scratches - reach the ferrous substrate a and j cause corrosion thereof.

| j '] 10 Although the invention is at first sight: intended to be applied to ferrous-based objects, it can prove to be advantageous in combi-i! naison with non-ferrous objects.

ij »J / (, i ii

I

H

S

I 'j: l] Î "

U

P

lîj

I

Claims (4)

2. Method for coating laminated surfaces according to claim 1 characterized in that the layer of stainless steel or molybdenum is dried in air or in an oven at 120 ° C -150 ° C. / / L · - ^ 7% 3. Laminated surface established by the method according to claims 1 and 2, characterized by a base substrate covered with a layer ΐ 5 of vitreous enamel before, in the finished state, a surface roughness jj 5 of 7.5 - 15 microns; a mother diaper | or stainless steel or molybdenum matrix applied, -! on the layer of glassy enamel and, finally, * 1 r? an outer layer of PTFS or HFP / TFE j coating; applied over the mother layer, jj 10 4. Container formed from a material produced by the process according to claims 1 and jj 2, characterized in that it comprises a substrate of ferrous base, a base layer of ceramic vitreous enamel on the base substrate, a layer of stainless steel or molybdenum covering the ce layer! branched out on the opposite side of the enamel layer by "i compared to the ferrous substrate and an external layer of -, anti-caking finish of PTFH or HFP / TFE which! covers and impregnates the layer of stainless steel or ‘20 with molybdenum. ? 5. Container according to claim 4, characterized in that the layer of stainless steel or of molybdenum forms an intermediate surface: comprising protrusions and microscopic interstices to receive the outer layer of PTFE or HFP / TFE. 5. Container according to claims 4 or 5, in substance as described with reference .4 to the accompanying drawings. 7. Surface coating process. laminated to make them resistant to abrasion, in substance, as described above. VA.U \ b