IL111199A - Paint compositions for high infra-red reflectivity with a low gloss for use for fabric - Google Patents

Description

PAINT COMPOSITIONS FOR HIGH INFRA-RED REFLECTIVITY WITH A LOW GLOSS TO BE USED FOR FABRIC οπκ—NTB-t ',χ cnnna nm^a ΓΠΤΠΠ 'Vyn yax 'uan .•n Tiny lis: p-n TUT an ' yn THE APPLICANT: :nt->p:.an STATE OF ISRAEL MINISTRY OF DEFENSE, ,*?K~W> nrma ARMAMENT DEVELOPMENT AUTHORITY, nV 'yxDK πτη'Εΐ m«nn P.O.Box 2250, Haifa 31021. 31021 Πΰ'Π ,2250 7.Π THE INVENTORS: 1. Shulamit WASSERMAN n»a¾»i© .1 2. Menachem MALIK p' ft orua .2 3. Dr. Igal E. KLEIN T' j? . N iu' .YT .3 4. Arie CALLAHORA The present invention relates to fabric paint compositions for high infra-red reflectivity. More particularly, the invention relates to paint compositions for fabric useful in the printing manufacturing process for the thermal infra-red region while maintaining a low gloss property.

BACKGROUND OF THE INVENTION.

Paints are generally defined as liquids, or pastes comprising a suspension of a pigment in oil or water. As known, thermal infra-red region of the electromagnetic spectrum refers to waves whose wavelengh exists roughly between 3 to 14 micrometers. Applications of thermal infra-red radiation exist in many systems and sub-systems for household applications, such as: radiative cooling or heating; for industrial uses, such as: solar collectors, heat exchangers; for military uses, such as: homing devices, surveillance, night vision devices and camouflage devices, etc.

The three main constituents of paints are: (a) Pigments, having the function to give the paint the opacity, colour and added durability. (b) Binders, which impart film forming properties and fulfill the optical requirements at visible light, and (c) Fillers, known also as extenders, which have the property to aid in protecting the paint from weathering of the dyes and also to reduce the gloss of a paint.

There are cases when it is most desirable that the layer of the film resulted from a binder, should possess a low gloss property, which is generally achieved by adding a filler material, such as calcium carbonate, metal silicates, colloidal silica, etc. These filler materials are actually used in most of the cases where no particular requirements on their absorption in the infra-red range is imposed. However, in case of films produced by paints which possess a high reflectance in the thermal infra-red range of 3 to 14 micrometers, these materials are not suitable.

In our previous Patent Application Number 110,683 there were claimed paint compositions for a high infra-red reflectivity with a low gloss property. The compositions mentioned comprise: polyolefin extenders, calcined pigments and metallic flake pigments, together with other known constituents, such as resin binders, solvents, stabilizers, dispersion agents, drying agents and the like. In the U.S. Patent Number 4,034,129, it is described a coating system having a high absorption in the visible range and low infra-red emissivity. The system comprises a two-layer laminate water-based system consisting of an alkali silicate as a binding overcoat cured at a relatively high temperature in the range of 150° to 550°C and a semiconductor oxide or sulfide as pigment. The patent is silent in respect to the issue of gloss property.

In the U.S. Patent No. 4,495,239 a wide band camouflage system is described. The system consists of a thin vapour deposited metallic reflecting layer as a base, and a top layer of paint which functions for camouflage in the visible range and the near infra-red region which is similar to the emlssivity of the paint in the range of 0.8 to 1.2 um. This paint is designed for high emlssivity in the spectral range of 3 to 12 um.

In another U.S Patent Number 4,560,608 the same Inventor as in the previous one, describes a camouflage material for nets, blankets or clothing suitable for their use in winter. It comprises a woven or non-woven material coated on both sides with a layer of plastic coating and which is covered on one side by a thin layer of a metal selected from aluminum, gold and tin. A printed coating of paint is applied to the metallized surface providing a imitation of a snowy landscape.The binder used has a high transparency in the ranges of 3 to 5 um and 8 to 14 um. Another U.S. patent number 4,879,171 deals with a thermal camouflage fabric system, which comprises a woven poly- olefin flat tape, coated with a layer of metal ,preferably produced by vapor deposition, and overcoated with a flexible support material. An additional protective layer is applied to protect the heat reflective composite material from damage. The patent does not mention anything on the incorporation of paints or pigments per se.

The above brief review illustrates the interest in the textile materials which possess a high thermal infra-red reflectivity, most of the reports on this object being carried out with a two-layer system.

It is an object of the present invention to provide paint compositions useful for printing manufacturing process which provides a coating with uniques and improved properties of increased reflectivity in the thermal infrared region while maintaining a low gloss. It is another object of the present invention to provide a paint composition for printing manufacturing process which provides a coating of increased reflectivity in the thermal infrared region, said coating consisting of a one-layersystem.

BRIEF DESCRIPTION OF THE INVENTION.

The invention relates to plastisol paint compositions for fabric which increase the reflectivity in the thermal infra-red region, while controlling the colour in the visible range and are maintaining a low gloss which comprise: (a) at least one plasticizer constituent, selected from esters resulted from phthalic or adlpic acid with an alcohol having a chain length of C3 to C12; (b) a binder, selected from resins or copolymers, alkyds, polyurethanes, vinyl and epoxy compounds, silicones, acrylic resins and mixtures thereof; (c) a pigment, selected from a leafing and non-leafing aluminum, metal oxides comprising at least one metal oxide calcined at a temperature of above 600°C, and (d) an extender selected from polyolefins, substituted polyoleflns and fluorinated polyolefins. The most preferred paint compositions are those containing a metallic pigment consisting of a non-leafing aluminum paste whose particle size provides a surface area 2 below 7 m /gram.

The invention is based on a synergistic action which results from the above main constituents. The most preferred plasticizer is di-octyl phthalate.

DETAILED DESCRIPTION OF THE INVENTION.

In contrast to the most of the prior references which are obtaining a high infra-red reflectance by using a highly reflective substrate and a transparent binder in a two layer system, according to the present invention the pigment is used in a one layer paint system. The nature of the substrate is immaterial regarding the high reflectivity which is imparted.

The colour in the above plastisol paint compositions can be selected according to any specific requirement, provided that the high reflectivity and low gloss are not affected. Generally, a volatile liquid is also incorporated to the paint composition, in order to dissolve the binder and to regulate the viscosity of the composition. The paint composition appears as a relatively viscous dispersion of the resin in a liquid plasticizer selected according to a particular use.

The paint compositions may be applied by known industrial techniques, such as printing or silk-screening on tarpaulins, plastic coated cloth, fabrics, etc. One may also conceive to apply the paint compositions by conventional techniques, such as spraying, brushing, dipping, etc.

In addition to the above main constituents, the paint compositions may also contain some auxiliary additives selected from: thickeners, drying agents, anti-skin agents, surface active agents, fire retardants, biocides, dispersants, flow-modifying agents, UV-stabilizers and fungicides.

The respective metal in the oxide may be selected from those able to provide a desired colour. Typical examples of such metals are: aluminum, iron, titanium, copper, cobalt* chromium, zinc, antimony, mamganese, nickel, magnesium and any mixture thereof. When the aluminum is used in the form of non-leafing flakes, it may be added either together with a mineral spirit or as a water-dispersable hydro-paste thus imparting a high reflectivity to the paint composition. Metallic aluminum pigments are well known in the art, being characterized by a number of distinct properties: - Shape, the particles being flaked, granular or spheroids.

- Particle size: fine, medium, coarse or very coarse.

- Appearance, powder, or a paste, and - Nature: leafing, where the particles are floating on the surface of the dry paint, or non-leafing flakes milled in a lubricant thus being wettable and easily dispersed throughout the paint composition.

A main constituent of the paint compositions required for the present invention is a plasticizer. Among the main properties for such a plasticizer, it should be mentioned: its compatibility with the other constituents; no affecting substantially the high infra-red reflectivity and low gloss, and to maintain the plastisol properties, such as surface texture and flexibility, during the product lifetime. Only the plasticizers mentioned above were found to be useful for the present invention; other plas- ticizers, such as epoxidized soya-oil, will be incompatible with the coating constituents.

Plastic sheets and plastic coated fabrics or cloths which were treated with the paint compositions according to the present invention, were found to possess high reflectivities in the thermal infra-red spectral range. The visual colour and the reflectivity in the near infra-red range is selected according to any specific requirement, by varying the nature and concentration of the pigment present in the paint composition. In this manner, by affording a high infra-red reflectivity to the respective material, it will enable unique applications such as: covers for greenhouses, unexpensive solar collectors or camouflage. When the substrate is a plastic sheet, the binder will be selected in order to be accordingly compatible. Thus for instance in case of a polyvinyl chloride sheet, the paint compositions would preferably contain a polyvinyl chloride binder.

Typical paint compositions according to the present invention, will contain the following constituents: - Polyvinyl chloride resin: between 20% to 35% by weight; - Plasticizer: between 12% to 25% by weight; - Pigments: calcined metal oxide, between 10 to 25% by weight; - Non-leafing aluminum paste, between 10 to 30% by weight and - Polyolefin powder, between 2% to 20% by weight.

The invention will be hereafter illustrated by the following Example, being understood that this Example is presented only for a better understanding of the invention, without limiting its scope as covered by the appended Claims.

In the Example, the amounts mentioned are by weight.

EXAMPLE 1.

A paint composition was prepared with the following ingredients : - 28 g of polyvinyl chloride; - 20 g of a mixture of dioctyl phthalate and di-octyl adipate (1:1); - 14 g of a mixture of calcined oxides of cobalt, aluminum, iron and chromium; - 23 g of a paste consisting of non-leafing aluminum; - 10 g of a polyolefin powder, and - 5 g of mineral spirit.

The reflectivity in the spectral range of between 8 to 12 micrometers was 0.3 and in the range of between 3 to 5 micrometers was 0.53.

Claims (9)

111,199/2 C L A I M S

1. Plastisol paint compositions for fabric which increase the reflectivity in the thermal infra-red region, while controlling the colour 1n the visible range and are maintaining a low gloss, which comprise: - at least one plasticizer constituent selected from an ester of phthalic or adipic acid with an alcohol containing between 3 to 12 carbon atoms; - a binder, selected from resins or copolymers, alkyds, polyurethanes, vinyl and epoxy compounds, silicones, acrylic resins and mixtures thereof; - a pigment, selected from a leafing, non-leafing aluminum, nd metal oxides comprising at least one metal oxide calcined at a temperature of above 600°C, and - an extender, selected from polyoleflns, substituted polyolefins and fluorinated polyoleflns.

2. Plastisol compositions according to Claim 1, wherein said constituents are present in the following ranges: - Polyvinyl chloride: 20% to 35% by weight; - Plasticizer : 12% to 25% by weight; - Pigment(s) : 20% to 55% by weight; - Polyolefln powder : 1% to 20% by weight.

3. Plastisol paint compositions according to Claims 1 or 2,wherein said pigment consists of a non-leaf1ng aluminum paste whose particles size provide a surface area below 7 mVgram.

4. Plastlsol paint compositions according to Claims 1 or 2, wherein said non-leafing aluminum flakes are added together with a mineral spirit.

5. Plastisol paint compositions according to Claims 1 or 2, wherein said non-leafing aluminum flakes are added as a water-dispersable hydro-paste.

6. Plastisol paint compositions according to Claims 1 to 5, wherein a volatile solvent is also incorporated in order to dissolve the binder and to regulate the viscosity of the composition.

7. Plastisol paint compositions according to Claims 1 and 2, wherein the metal in said oxide is selected from iron, titanium, copper, cobalt, aluminum, chromium, zinc, antimony, manganese, nickel, magnesium and any mixture thereof.

8. Plastisol paint compositions according to Claims 1 to 7, wherein auxiliary additives selected from fire-retardants, thickeners, drying agents, UV-stabi 1 izers and fungicides are incorporated.

9. Plastisol paint compositions for fabric, substantially as described in the specification and claimed in any one of Claims 1 to 8. For the Applicant Simon Lavie Patent Attorney