COMPOSITION FOR COATING, SEALING, AND PROTECTING PURPOSES

Abstract: Composition for coating, filling, binding, and protection, comprising rubber, whereby it comprises rubber having a particle size of at most 0.4 mm present in an amount of 20-50 % by weight, and a curable polymer base present in an amount of 40-55 % by weight, which components after curing of said polymer base is the elastic and adhesive part of the composition. The invention further relates to a process for preparation, and a process for applying said composition.

Description: COMPOSITION FOR COATING, SEALING AND PROTECTING PURPOSES. DESCRIPTION Tecni ca I field The present invention relates to a composition for coating, tightening, and protecting purposes, a process for its prepa¬ ration, as well as a process for its application. The object of the present invention is to obtain a composi¬ tion, which can be used as a coating of surfaces, which are subject to corrosion, and mechanical attacks; as a sealing agent for water and other liquids at tube joints, roofing, point-sealing of ceramic ti les, metal sheets, and the like, and which composition is very resistant to mechanical wear and attacks by chemicals including water. Background of the invention. SE-A-7709649-3 describes a corrosion resistant coating compo- sition, particularly for external rust protection of vehicle chassies, which composition consists of a polyurethan polymer, waste rubber, water free black coal tar, zeolitic dr ing agent. This composition .fulfi lls generally its object, but has some disadvantages by strongly smelling of black coal tar, which prevents it from being used in more resticted spaces, and leads to that well venti lated spaces are required at the application, as well. Further, the black coal tar leads to the fact that the coating obtains a black colour, which often may not be of no importance, but as often is not acceptable, but one demands in stead a pigmented product with a colour pigment by choice. Besides these drawbacks, which is of a cer¬ tain cosmetic nature, one often requires a sti ll higher wear¬ ing resistance, resistance against attack by chemicals, parti¬ cularly in alkaline environment, and temperature stabi lity. Description of the present invention. It has now surprisingly been shown possible to be able to eli¬ minate these problems by the present invention, which is cha¬ racterized in that it contains rubber with a particle size of at most 0.4 mm, and present in an amount of at most 50 7. by weight, and an isocyanate curable polymer base of the poly- hydroxy type in an amount of 40-55 '/. by weight, a polymer cur¬ ing isocyanate in an amount of 18-30 % by weight, and an ali¬ phatic polyether glycol in an amount of 1 to 5 % by weight. Further characteristics are evident from the accompanying lai s. The curable prepolymer is preferably an isocyanate curable polyurethan (DESMODUR-ha rdene r; DESH0PHEN 1150-prepo Lyme r ) but also isocyanate curable epoxy polymers can be used. Suitable binding agent of polymer type which are curable by socyanate active hardeners are different polyols, polyester bases, having a molecular weight of 200 and more. Other poly¬ mer materials are epoxy resins which are pri ari ly dissolved in a keton, or a glycol ether, and are then cured using an •isocyanate. acti e hardener (e.g. DESMODUR) or amino group active hardener. Suitable, epoxy resins have a molecular weight of 1000 or more. The polyols used can either be a polyester, such as DESM0PHEN 1150, or the like, and/or an aliphatic glycol, or more simple, such as ethylene glycol, diethylene glycol, triethylene gly- col . All types of rubber can be used as a rubber material, such as waste rubber, waste rubber tires, raw rubber, and other rubber qua I i t i es . Thus it has turned out that 20-40 % by weight of rubber pow¬ der, suitably waste rubber, having a particle size of <0.4 mm, preferably 0.05-0.2 mm, 40-50 % by weight of a polymer base, 1-5 '/. by weight of an aliphatic polyether glycol base, and 18-25 % by weight of an isocyanate hardener give excellent products within the scope of the present invention. Thus these compositions have, in cured state, a very high elasticity, and wearing resistance. In the case the polyester base con- tains moisture a zeolite drying agent should be added, alter¬ natively active aluminium oxide, or basic aluminium silicates. EXAMPLE 1. 40 parts per weight of waste rubber having a particle size of 0.1-0.2 mm were intimately mixed with a mixture of 40 parts per weight of DESM0PHEN 1150, and 2 parts per weight of poly¬ ether glycol (triethylene glycol). To this comixture then 18 parts per weight of an isocyanate active hardener (DESM0DUR) were added for the curing of the polymers. The composition prepared was used for the preparation of dif¬ ferent test coatings for testing. A product of Example 1 above (A) was tested and compared with a product (B) of SE-A-7709649-3, the Example, with regard to wearing resistance, heat resistance, adherence to steel, and chemical resistance. Wearing resistance ,, Plates with applied coatings of above were handled in .a tumb¬ ler for 5 days (120 hrs) together with 200 g of stones. The volume of material having been worn off, given in mm , was then measured. A= 19 mm 3 B=105 mm Cylindrical test bodies of the respective product were forced over an emery-cloth having 60 particles per cm with a pres- sure of 5 N, and length of 20 m, whereupon the volume worn off was determined. A=145 mm " B=470 mm " Heat resistance Plates with applied coating were hanged vertically for 2 days (48 hrs) at different temperatures, the samples/plates were then acclimatized to ambient temperature (20 C ) , whereupon they were checked ocularly. A= withstand 150°C B= withstand 80°C Adherence to steel Coatings on steel were tested for traction for determining the adherence abi lity. A= withstand 4.0 MPa prior to burst B= withstand 0.8 MPa prior to burst Chemical resistance Test coatings of the respective products were subjected to different oi ls, whereby one could generally determine that sample B miscoloured all such liqiuds, whi le sample A did not give any mi s co lourat i on . At testing in acidic aquoes environ¬ ment (HCl 30%; HN0- 10%; H 2 S0, 10%; or CH-C00H 50%) the re¬ sistance is just about the sam£. In an alkaline aqueous envi¬ ronment (NaOH or NH.0H) sample A is better. The water vapour permeabi lity is less for sample A than it is for samp le B . App lication Sample A can be applied in thicker layers (2.5-3 mm) on verti¬ cally hanging test ng plates compared with sample B which a I lows 1.5 mm, only. In connection with the preparation of the present composition one should preferably put the product under vacuo, whereby, in particular, the wearing resistance, and the chemical re¬ sistance are further improved. Furthermore, the aging resist¬ ance, moisture resistance, and the traction strength are im- proved. The pressure in the vacuo step for elimination of air should be 0.8 bar, but can in case of very igh viscous compo¬ sitions be further reduced down to 0.5-0.6 bar. Application of the composition can be effected in different ways, such as by means of simple manual painting, by mechanic¬ al painting, as well as by means of high pressure spraying. At high pressure spraying a modified conventional high pres- sure spraying apparatus of two-component type is suitably used, wherein the composition, exclusive of hardener, and hardener are brought together prior to the outlet of a mixing tube ( ixer) and is brought forward to a spraying gun via a heat taped high pressure hose. The pressure on the composition shall be so high that a well distributed spraying mass is ob tained (atomized), which, at viscosities of the composition normally appearing, is obtained at 160-200 kg/cm and a tem¬ perature of >40 C, preferably 40-80 C, more preferably 45-60 υ C. Normally the viscosity of the composition is such that the high pressure pump as such does not manage to draw the compo¬ sition into the apparatus at normal temperature. Thus, a pres¬ sure plate has been arranged to the high pressure spray appa- ratus, with success,, uihich plate fits snuggly into the vessel where the composition is prepared, whereupon the pressure plate is pressed down into the preparation vessel either mechanically, pneumatically, or hydraulically, so that the composition is pressed up into the high pressure spray appara- tus. In order to increase the curing of the composition above an accelerator of the curing reaction can be added in an amount of 0.1-0.5 % by weight Examples of such accelerators are d i - butyl distannium di laurate, or corresponding lead compounds. In order to reduce the fire risk a flame retarder can be added to the composition such as a phosphite compound, which is added in an amount of 5-15 % by weight. Nowgard V-4 is an example of a retarder. The composition can be made thixotropic as well, by adding a suitable jelling substance.

Claims: C LA I MS . 1. Composition for coating, fi lling, binding, and protection comprising an isocyanate curable polymer and rubber, characte¬ rized in that it consists of rubber having a particle size of at most 0.4 mm present in an amount of 20-50 % by weight, and an isocyanate curable polymer base present in an amount of 40-55 % by weight, a polymer curing isocyanate in an amount of 18-30 % by weight, and an aliphatic polyether glycol in an amount of 1-5 % by weight, which components after curing of said polymer base are the elastic and adhering part of the composi t i on . 2. Composition according to claim 1, characterized in that the polymer base comprises a polymer of polyester type in a mixture with a polymer base of polyether glycol type. 3. Composition according to claim 1, characterized in that the rubber has a particle size of 0.01-0.2 mm. 4. Composition according to claim 1, characteri-zed in that the polymer base is an isocyanate curable polyepoxide. 5. Composition according to claim 1, characterized in that the polymer base is a polyurethane. 6. Composition according to claim 1, characterized in that the composition further comprises a zeolitic drying agent, an active aluminium oxide, and/or an aluminium si licate. 7. Composition according to claims 1-6, characterized in that the composition further comprises a colouring pigment. 8. Process for preparation of a composition of claims 1-7, characterized in that the rubber powder having a particle size of at most 0.4 * mm is provided with a curable polymer base, an aliphatic polyether . glycol, and optionally a colouring pig¬ ment, whereupon the mixture is subjected to a vacuo pressure o f a t l e a s t 0 . 9 b a r . 9. Process according to claim 8, characterized in that the subpressure is 0.8 bar, preferably, however, not lower than 0.5 bar. 10. Process for applying a composition according to claim 1-7, by means of high pressure, characterized in that the composi¬ tion is drawn into a modified two-component high pressure pump together with a hardener; that a pressure plate is placed on the high pressure pump, which pressure plate is pressed down into the composition in order to press this up into the pump; that the composition is heated to >40 C in connection with said pump, to obtain a spraying picture of finely dispersed composition having a pressure of 150 kg/cm or more.

Inventors: EK ROLF LENNART, NYGREN SUNE BERTIL, EK, ROLF, LENNART, NYGREN, SUNE, BERTIL
Applicants: STOCKHOLMS TRADE CO
Application year: 1986
Main classification: C09K3
IPC codes: C08L75, C09K3