US2442911A - Antisweat compositions - Google Patents

Description

Patented June 8, 1948 stares; PAIENT oEELC-E, I ....2442,911

IIF W AHO S TJQNS Floyd E. Trenty san Lorenao; andflrthur E. "Burns; 'Jr;,- Vallejo, -Calif.,- assignors, by mesne. assignments, -to Universal Sta-Dri c ornoration a corporation of California 1 2 Claims.

The interior surfaces of a ships skin and the exterior "surfaces of shipboard saltwater piping ystems are maintained at ess'entiallyocean temperature by therapid conduction ofheat through theli'elatively thin'stel hullplating' orp'ipe walls;

when the "warm damp 'ai'r nearlyalwayspresent inside a ship contacts these cold surfaces; con densation occurs. This conditioni generally termed "sweating, is a problem of considerable im ortance inship "operationand maintenance. The condensate or sweat drips from "overhead piping'and down 'the' hulljplating, often in such quantity as to be extremely disagreeable to the: crew "and "to make impossible -the proper storage of cargo which shouldnot become wet.-

various ty es of insulation havebeen applied to p 'and hu'll plating in'an endeavor to eliminats-"=sweatrng; Although corkboard and" like heavy duty insulating materials were found effec-' completely removed from many vessels-wFibrousglass board insulation was used-toreplacecork insulation insom'e' services but 'a complete substitution wa's notpractical owing to" difficulties application ana tdhigh cost? Therefore; a rieed exists for afire retardent anti-sweat material having areasoiiable"cost'andsimple applicatioii fi araj te'risticsl The discovery by the Navy that thin films of highly pigmented"'paiht'having a, low organic binder content" were" fire retardent permitted the development of fire" retardent'a'nti-swe'at paints. By "substituting a "granular" fireproof" exfoliated mica; commonly known as'H/eriniculitafor granulated cork and by the use of a fire retardent binder paint, a reasonably effective anti-sweat paintwas obtained. To apply this type coating, fire retar'denfbinder paint was brushed on a surface andallowedtp dry until tackywDry-exfoli ated mica granules were thenblown ofi thesurface with a compressed airf g'un,"the-g"fanugles stickingto'the wet"paint filmZ"When dry,- the surface was sprayed with one orin'ore ts of fire retardent paint. Although ti sweat paint applied by the above rawing. Application June 29, 1945, SeriaI'No. 602,42 4' 1 a;

(01. meats) method is reasonably effective in preventing sweating, these are serious objections to theapp1ication;method.- These are-largely the result of physical weaknesses inherent in the exfoliated or eXpandedmicagranules; This materiarhas a very friable laminar structure which is readily broken up into small flakes. It has been found impossible to avoid the formation of many such flakes during shipment, storage," andapplication of the vermiculite granules. Whenthe dry vermiculite is applied with a'cornpressed air gun,- the fine particles and flakes arereadily carried by the-air stream and impinge'uponand adhere to the et'binder'paint. ':"Howeve1'.,'-the=fine flakes tend 'tdcoat over the surface andto prevent-the adherence ofthe larger-vermiculite-granules which are essential. for satisfactory anti-sweat prope'rties; A 'l'arge amount'of overspray necess'arily results from the bouncing" ofi of many vermiculiteparticles from areaswhere the binder hasalready been 'coveredz As a consequence, it is necessary to cover any machinery present and to clean up the area after the application.

When a; vermiculite granule adheres to the wet binderf it is cemented "to a surface on only one side-J I? Since these particles are laminar in -structure and easily'broken,-=the slightest abrasion-is sufficient to split offthe greater portion of the granules: "Later application-bf a fire retardent paint" seal coats only-partially the-vermiculite particlesf it does notbvercome this difficulty-and does not produce a surface of any great physical strength. 5 --Various workers have attempted to eliminate thedifli'culties described above by use of different methods for application of anti-sweat" paint.

The majority of these attempts have involved the premixingbf fireretardent' binder paint and vermiculite granules 'tj f'orma slurry or porridge wh'ichcan' be sprayed'on a surface in a single coat." However, when this is done, the porous vermiculite granules" absorb large quantitie'sizof paint." 'Toobtain a, spr'ayable mixture, not-less thanten poundsof paint must be mixed with onepound "of"ver miculite" granules. To obtain satisfactory fire' retardent -properties in the amisw'eat "paint fi1m;"n'ot over- L0 pounds of binder paint canbe used. for ea'chpoundof vermiculite; Therefore, all previousattempts to app y fi retardent anti-sweatpaint in a single composite coat have been unsuccessful;

' Proceeding in accordance with this invention one can make spray application of fire retardent anti-sweatpaint in "a' single application.- essential ancl'unique part ofthis process-is the aeaaen use of a binder paint-water emulsion vehicle. By the use of the emulsion vehicle, all the weaknesses of previous unsuccessful sprayed antisweat coatings are eliminated. The water acts as a carrier and permits the spraying of mixtures containing as little as 2.0 pounds of binder paint per pound of vermiculite. After application, the

water evaporates, leaving the vermiculite securely cemented to the desired surface. The emulsion vehicle is quite thixotropic or false bodied with the result that any tendency of the admixed granular insulating material to separate during an extended storage period is absent. The coating has little tendency to sag and can be sprayed on a surface to a thickness-of at least one-half inch in a single coat and upon a single application. Such all the way through. These properties can be obtained in no other way than through the use of a suitable water-binder paint emulsion vehicle, To apply vermiculite properly it is essential that it be applied in water emulsion along with a selected organic binder. The simplest composition is one made up within the following limits:

Parts by weight Vermiculite granules about 4 Water 1 to 6 Organic binder to 4 Emulsifying agent 0.01 to 1 The emulsifying agent and water hold the vermiculite in a stable suspension along with the binder until the mixture is sprayed against a wall. Then the binder sticks the emulsion onto the wall surface. This composition is prepared by forming the emulsion, including the binder, and finally stirring in the vermiculite. This material is not fire retardent. Its color is essentially that of the vermiculite. If desired, another application can be made later of a suitable color carrying paint.

When the fire retardent property is desired, a suitable pigment is added. A suitable thinner or solvent and a paint drier are also preferably included to ensure the composition is not too viscous with the added pigment and to improve drying; the inclusion of these is not essential although it is generally desirable. The foregoing composition can be modified by inclusion of the following:

Parts by weight Pigment 1-4 Thinner or solvent /z2 Paint drier -0.1

In forming a composition including the pigment one proceeds to grind the pigment in the organic binder to form in eifect a paint. Then the proper quantity of drier is added, if desired. Then the emulsifying agent and water are added and the mixture emulsified. Finally the vermiculite is stirred in, care being taken not to break either the emulsion or the fragile vermiculite particles.

Pigment is not essential to the composition but its inclusion is required if a composition having excellent fire retardent properties is desired. Almost any standard paint pigment can be used separately or in part depending upon the final color desired and the degree of fire-proofness desired. Titanium dioxide can be used to obtain hiding power, calcium carbonate and antimony oxide for fire retardence, lampblack or iron oxides for tinting and various extender pigments for control of viscosity.

The organic binder can be any material which,

a thick coating dries hard a film and in the presence of available oxygen, takes up oxygen to form a solid film. Such materials are generally well known in the paint art and. include the drying oil modified polyhydric alcohol-polybasic acid varnishes such as oil modified glyceryl phthalate varnishes, oleo-resinous varnishes, phenolic resin varnishes and drying oils such as tung oil, linseed oil and dehydrated castor oil. In the case of the simplest composition, if the binder is extremely viscous sufiicient volatile solvent should be employed to enable the binder to be incorporated as a fluid in the emulsion. While in the above we have indicated that the vermiculite-binder ratio can vary between 8 to l and 1 to 1, it is a feature that the ratio can be and preferably is as high as 3 to l and as high as 8 to 1.

The thinner or solvent can be a petroleum naphtha, a coal tar naphtha, a lacquer solvent, turpentine or other type of paint thinner. In all cases, however, the organic binder should be soluble in the selected thinner and the thinner should have a satisfactory evaporation rate. The amount of thinner required is quite variable and depends upon the viscosity of the organic binder, the amount of pigment and other constitutents of the composition.

The paint driers are the standard metallic soap driers of commerce. Lead and manganese naphthenates are particularly suitable. sufficient drier should be used to cause the organic binder to dry at the optimum rate.

The amount of water required is dependent upon the other ingredients of the formula. It is essential, however, that sufficient water be used to obtain a fluid composition suitable for application through a spray gun or by a trowel application.

The emulsifier coats the vermiculite particles and cushions it during mixing and spraying. The emulsifying agent can be of any type which will (1) yield a stable dispersion of the organic binder and water, (2) hold the vermiculite in suspension and (3) include an element or group which evaporates from the film during the drying period and leaves a water insoluble residue. Ammonia fatty acid soaps, amine soaps and morpholine are particularly suitable for this service as are other like emulsifiers containing easily volatile constituents which evaporate to leave a substantially water insoluble residue.

The size of the vermiculite is important and the presence of granules coarser than No. 2 U. S. sieve size or finer than No. 30 U. S. sieve size is not desirable. The optimum particle size range is ordinarily between the limits of No. 4 U. S. sieve size and No. 20 U. S. sieve size, that is substantially all the material is retained on a No. 20 sieve and substantially all will pass a No. 4 sieve. This material is relatively coarse. While we prefer to use the aforementioned coarse material we have used successfully a vermiculite which was within the following size distribution specification:

when applied as In determining the size and distribution grams of the vermiculite is shaken through a series of U. S. standard sieves consisting of Nos. 4, 10, 20, 30, 40 and 100, in the order named. The sample is shaken by hand for 30 minutes or in an acceptable mechanically operated shaker for minutes, the shaker imparting a rotary motion and a tapping action of a uniform speed of between 140 and 160 taps per minute. The term vermiculite granules is employed herein and in the claims as an expression of this size limitation.

As a specific example and to illustrate preparation of a composition within the present invention, the following component raw materials were mixed and ground to produce a uniform homogeneous product free from grit and capable of being readily broken up by a paddle to a smooth, uniform pigmented paint of acceptable consistency; the paint did not liver, thicken, curdle, jell or show any other objectionable properties after long periods of storage.

Pounds per 100 gallons Calcium carbonate 816.0 Antimony oxide 104.0 Alkyd resin solution 317.0 Paint thinner 143.0 Lead naphthenate drier 2.8 Cobalt naphthenate drier 1.1

The grades of the various materials utilized were as specified more particularly in Bureau of Ships Ad Interim Specification 52P62(INT) 2 January 1945. The alkyd resin was a soybean oil modified glyceryl phthalate resin (70% soybean oil-% glyceryl phthalate) in solution in a thinner, the solution containing 70% by weight of the oil modified resin. This pigmented composition was then mixed with water in the proportion of one gallon of the foregoing material to two gallons of water while an ammonium oleate soap and petroleum spirits were added, respectively in the proportion of 0.16 pound and 3 pints. The petroleum spirits had a flash point of 140 R, an initial boiling point of 356 F., an end point of 473 F., and otherwise corresponded to the heavy petroleum spirits specification of Bureau of Ships Ad Interim Specification 52'19- (INT) 2 January 1943. When all of the foregoing materials were emulsified, a granular vermiculite was added in the proportion of 6 pounds to each gallon of the pigmented composition originally added. This composition was sprayed on a steel surface primed with a zinc chromate primer. A heavy, durable coat resulted, one which provided improved heat insulating characteristics.

Similar and equally satisfactory compositions have been made and applied utilizing as the organic binder an oleo-resinous varnish conforming to Federal Specification TT-V-121A, or a phenolic varnish conforming to Bu. Ships Ad Int. Spec. 52-V-17 of 1 February 1942, or a heat bodied linseed oil conforming to Bu. Ships Ad Int. Spec. 52-0-19 of 1 December 1942. These specifications are incorporated by reference.

The term "vermiculite is used herein as describing mica or micaceous minerals which have been suitably heated so that the particles are exfoliated; it is referred to as exfoliated mica and various trade names are used to describe it.

It is a feature of the composition of this invention that it can be sprayed onto a surface and, when the emulsion vehicle dries, the fin-al outer surface is quite rough. We have observed that such a surface is far more efiective in prevention of sweating than a far heavier coating of a material of comparable or even higher unit heat insulation value. We believe that the multitude of projecting vermiculite particles, each of a laminated nature and containing many capillary passages, holds a layer or skin of dry air against the surface. This increases materially the heat insulation value of the sprayed coating. Even when such a coating is subject to severe conditions for a long period, sweating is held to a minimum for the capillaries in the vermiculite retain the moisture and dripping of water is reduced very considerably. In many cases, the coat will hold the moisture and no dripping will be evident during the existence of severe conditions conducive to condensation until these conditions have changed to less severe conditions under which the condensed moisture retained by the vermiculite evaporates. Because the surface coat is rough and is not too hard it is eifective as a sound absorbing medium as well as an insulating medium.

In making up the composition for use the vermiculite should not be added until one is nearly ready to use it for, while the emulsion is stable in the absence of the vermiculite, in its presence it sets-up and hardens within about twenty-four hours.

We claim:

1. A coating composition comprising a waterin oil type emulsion of a drying oil and granular exfoliated micaceous materials, the water being present in a-quantity sufficient to provide a free flowing composition suitable for application to a surface by spraying, the drying oil being present in a quantity only sufficient to bond the micaceous material to a surface, the granular micaceous material being present in a quantity sufficient to provide a rough surface coat havig heat insulation properties.

2. A coating composition comprising a waterin-oil type emulsion of a drying oil and granular exfoliated micaceous material, the water being present in a. quantity suflicient to provide a free flowing composition suitable for application to a surface by spraying, the drying oil being present in a quantity only sufiicient to bond the micaceous material to a surface, the granular micaceous material being of a size such that substantially all thereof will pass a No. 4 U. S. sieve and is retained on a No. 20 U. S. sieve and being present in a quantity sufficient to provide a rough surface coat having heat insulation properties,

FLOYD E. TRENT. ARTHUR E. BURNS, Ja.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS me Date