FR2502632A1 - Coating compsn. for ship decks and walls and floating structures - comprises artificial cement, siliceous sand and styrene!-butadiene! copolymer latex - Google Patents

Abstract

A coating compsn. for the decks and walls of ships and floating structures comprises an 'in situ' prepd. mixt. of 50 kg artificial cement, 150 kg siliceous sand, 13 kg styrene/butadiene copolymer aq. dispersion diluted to 22.5% solids and contg. 150 g silicone oil as antifoaming agent and the rest pure water. The compsn. has a flame resistance exceeding the min. requirements imposed on propagations (more than 20 mins) and does not emit toxic smokes, being free from HCl and HCN. It also has excellent water, sea spray and UV resistance.

Description

 The object of the invention relates to a composition intended for coating ship decks.

It is intended for the coating of the decks of ships and other floating devices, designed and developed to be in compliance with the new defined safety standards, and
by international conventions.

 The coatings known to date have been mortars formed by a mixture of cement and sand (or other mineral fillers) plasticized with emulsions of natural latex or neoprene latex.

 Compositions based on natural latex do not withstand flame propagation tests during Standard Fire Tests beyond 12 to 13 minutes, but have the disadvantage that new safety standards require 15 minutes minimum .

 Those based on neoprene latex resist well the Standard Fire Test for 15 minutes, but have the disadvantage of releasing during this Test toxic fumes and in particular hydrochloric acid and cyanhydric acid vapors that .

 Finally, very localized experiments were carried out in France and abroad using plasticized mortars formulated with polyvinyl latex. These formulas have never produced conclusive results because of their poor resistance to the relatively high humidity which characterizes the atmospheric maritime atmospheres.

 The manufacturing process, which is the subject of the patent, differs radically from all traditional bridge coating formulations and its formula has the following advantages: - Resistance to flame propagation greater than 20 minutes, - Total absence of chlorine and ammonia , which prevents the formation of toxic fumes of hydrochloric acid and hydrocyanic acid in the event of fire.

- Excellence resistance to water, sea spray and ultraviolet rays, which allows it to be used on both interior and exterior decks.

 Finally, the fumes emitted during fire tests for 30 minutes never exceed the permitted opacity limits.

 According to an embodiment given by way of nonlimiting example of one of the embodiments of the object of the invention, the listed materials are used in the proportions indicated with the mixture operated "in situ" - Artificial cement 50 kg - Silica sand 150 kg - Aqueous dispersion of copolymers of 13 kg styrene butadiene diluted to 22.50 k of dry extracts, added with an anti-foaming agent 150 g based on silicone oils and a complement of pure water.

 According to variates of execution one can replace all or part of the siliceous sand by an equal weight of crushed pumice stone of equivalent particle size or alternatively replace part of the artificial cement by a molten cement to obtain a faster hardening of the mortar.

 The concentration of the dispersion of styrene-butadiene copolymers is reinforced to 33.50% of dry extracts instead of 22.50% and also comprises on the surface a terminal layer of the same formula as slip, but containing silica sand from 0 to 0.5 mm on which is then applied two coats of special paint based on polyurethane with pigmentation reinforced with ultraviolet to cover exposed bridges.

 In certain applications, part of the silica sand is replaced by an equal part by weight of hydroxide powders to further increase the fire resistance of the composition. Finally, the sand can be replaced by mineral fillers such as: crushed pumice, pozzolan, expanded shales, vermiculite, perlite.

 The basic composition and all the variants defined above are intended to be used on the decks and walls of ships and external or internal floating devices.

 They can also find industrial applications when similar conditions of use are encountered, in particular for the protection of metallic structures exposed to very high relative humidity or in contact with aggressive vapors as well as in a marine atmosphere.

According to an embodiment given by way of nonlimiting example, the composition of the coating is obtained by mixing operated "in situ" preferably in a conventional concrete mixer using the following dosages - 50 kg artificial cement - 150 kg silica sand 0.2 mm - 13 kg aqueous dispersion of styrene copolymers and
butadiene containing 22.50% dry extracts (repaired
made of 55% styrene and 45% butadiene) - O kg 15 anti-foaming agent based on silicone oils.

 Finally, to add the consistency of the mortar favorable to the application, a supplement of variable fresh water is added depending on the state of dryness of the sand used. This additional water is of the order of 10 liters per batch, when a perfectly dehydrated sand is available.

 The normal concentration of dry extracts of 22.50% of the aqueous dispersion of styrene butadiene can be reinforced up to 33.50% in certain special formulas, especially when the applications concern particularly exposed bridges.

 It can be reduced up to 11.50% in the case of bulky fillings to be carried out, but in the case where the terminal layer must be delivered to traffic, this must normally be dosed at 22.50%.

 To increase the fire resistance beyond 20 minutes, the above basic composition can be modified by incorporating hydroxides in the form of powders which replace part of the sand in equal parts by weight.

 Before applying the mortar to the bridges, they must be cleaned properly and degreased if necessary.

 We start by applying with a brush broom a layer of semi-liquid slip consisting of a mixture in two equal volumetric parts of artificial cement and silica sand wasted using the dispersion normal styrene butadiene at 22.50% dry extracts, without adding water.

 The sand and cement for the underlay are introduced into the concrete mixer and thoroughly mixed.

 The styrene butadiene dispersion added with anti-foaming agent and diluted with fresh water to obtain the required concentration of dry extracts is then incorporated and finally the additional fresh water necessary to obtain the desired final consistency is added.

 The total mixing time required is around 12 minutes.

 The mixture thus obtained is deposited progressively on the freshly applied slip and is spread out using a trowel to obtain the required thickness.

Claims (4)

 10 Composition intended for coating ship decks, ship walls and floating devices and ensuring resistance exceeding the minimum standards imposed on flame propagation and suppressing toxic fumes emanations, characterized by a mixture operated "in situ" of - Artificial cement 50 kg - Silicon sand 150 kg - water dispersion of 13 kg  of styrene butadiene copolymers diluted with  22.50% dry extracts, added to 150 g  an anti-foaming agent based on silicone oils  and a supplement of pure water.  20 Composition according to Claim 1, characterized in that the concentration of the dispersion of styrene butadiene copolymers is reinforced to 33.50% of dry extracts instead of 22.50% and further comprises on the surface a terminal layer of the same formula as the slip, but containing silica sand from 0 to 0.5 mm on which two layers of special polyurethane paint are then applied with pigments reinforced with ultraviolet to coat exposed spots.  30 Composition according to claim 1, characterized in that all or part of the silica sand can be replaced by an equal weight of crushed pumice, pozzolan, expanded shale, vermiculite, perlite, equivalent particle size.  40 Composition according to Claim 1, characterized in that, depending on the applications, the cement can be replaced by molten cement and the silica sand by flame-retardant hydroxide powders.