US2085124A - Vitrifiable coating composition - Google Patents

Description

Patented June 29, 1937 FFEQE VITRIFIABLE COATING COMPOSITION No Drawing. Application April 9, 1935, Serial No. 15,472

12 Claims.

This invention relates to the art of applying fused coatings and more particularly to the applying of markings or ornamentation to glass, ceramic or metal surfaces by the application thereto of powdered fusible material that is afterwards fused onto the surface.

In the art of glass making, colors have heretofore been applied to glass by fusing finely ground colored glass onto its surface. Usually the colored glass is crushed and then finely ground and thereafter suspended or made into a paste with collodion, a vegetable oil, turpentine or other similar vehicle. The desired design is then formed with the resultant mixture on the surface of the article to be coated and heat is applied to drive off the vehicle and fuse the finely divided glass onto the surface.

A major difficulty that has been encountered in the use of this type of process is that the vehicle is either driven off at so early a stage in the heating that the glass becomes disarranged or entirely falls from the surface to which it is to be fused, or that the vehicle carbonizes upon heating or otherwise decomposes or reacts to cause undesirable coloration or darkening of the finished decoration.

According to the present invention it has been discovered that the aforementioned highly undesirable occurrences may be prevented and fused coatings, decorations, or markings may be applied simply and economically by using as a vehicle for the finely divided glass certain alkylated aryl compounds and particularly certain alkyl naphthalenes, alone or in a mixture with other materials.

Alkylated aryl compounds are commonly formed either by the reaction of alkyl chlorides on aryl compounds in the presence of a catalyst such as an aluminum chloride or by the condensation of olefins with aryl compounds, also in the presence of a catalyst. Depending upon the proportions of alkyl and aryl radicals present and upon the extent to which the reaction is caused or permitted to proceed, mono-alkyl, dialkyl, or higher poly-alkyl derivatives or mixtures containing various proportions of these derivatives may be formed. In general it has been found that for the purpose of this invention it is unnecessary to separate the various derivatives thatare usually formed but that the mixture of monoand poly-alkyl aryl compounds, particularly if it contains a fairly high proportion of the poly-alkyl compounds, can be used in the form in which it is obtained.

In using such a mixture of alkyl aryl compounds, or using any one alkyl aryl compound by itself, the finely ground fusible material which is to be used in forming the coating or decoration, is ordinarily passed through a screen or the like to remove any over-sized particles and dispersed in the vehicle. The resultant mixture, which may vary in consistency from that of a liquid to that of a rather thick paste, is then spread upon the surface to be coated in any convenient manner. Commonly, such material is applied with a brush or spray but it can be applied by dipping the object to be coated. Silk screen stencils have also been used in applying the coating with excellent results.

After the coating has been applied, the object carrying the coating is heated, as by being placed in an oven, until the vehicle is completely expelled and the fusible material welded securely to the surface. The vehicle used in accordance with the present invention, has been found particularly advantageous because it neither releases the fusible material prematurely, nor does it char or otherwise discolor the finished decoration.

Specifically, it has been found desirable to substitute naphthalene with one or more alkyl groups, such as amyl groups, for the purpose of forming a satisfactory vehicle according to this invention. Thus, as one example of the formation of the vehicle, the formation of a mixture of amyl naphthalenes will be described. It is to be understood, however, that this invention is not limited to the employment of amyl naphthalenes as the vehicle nor to the employment of a mixture of monoand poly-substituted amyl compounds. The same general principles apply to the use of numerous similar alkyl aryl compounds either singly or in mixtures.

A mixture of amyl naphthalenes well suited for use as a vehicle according to this invention and comprising mostly monoand di-amyl naphthalenes has been obtained by reacting 854 parts by Weight of naphthalene with 831 parts by Weight of mixed tertiary and secondary amyl chlorides. A mixture of the two was heated to C. until they formed a homogeneous solution and 10 parts by weight of aluminum chloride were then added in very small portions. The reaction was substantially complete by the time 8 parts by weight had been added. The mass was thereafter heated to C. for a few minutes to fully complete the reaction and the resulting products washed with 2% hydrochloric acid, water, 5% sodium hydroxide and then more water.

Upon testing the product by distillation a small amount of amyl chloride was recovered and 320 parts of naphthalene were found to have been left unreacted. However, there were 543 parts by weight of mono-amyl naphthalene and 283 parts of di-amyl naphthalene. The mixture of amyl naphthalenes was found to be a satisfactory vehicle for the fusible material just as it was recovered and it was even found possible'to'use the product of the above reaction, without removing the naphthalene, without serious disadvantage.

In addition to preparing amyl naphthalene by use of the proportions above mentioned, other quantities have been used and it has been found that if sufiicient amyl chloride is present, for example, 1 to 2 molecular weights per molecular weight of naphthalene, a considerable amount of the tri-amyl naphthalene will also be formed. Low temperatures, for example, 5-10 C. also favor the formation of the poly-alkylated derivatives. However, since the boiling points of the amyl naphthalenes are all quite high at ordinary pressures, mono-amyl naphthalene boiling at around 280-3l5 (3., di-amyl naph halene at around 325-360 C. and tri-amyl naphthalene at around Mil-390 C. it is rather difficult to distill them and hence to determine the exact amounts of each formed in any one reaction. For the purpose of this invention it seems sufficient for us to know that these high boiling alkyl aryl compounds, such as the amyl naphthalenes, or mixtures thereof, all operate satisfactorily according to this invention.

Apparently there is some advantage in having at least a portion of the tri-alkyl derivatives or other poly-alkyl derivatives present because of the high temperature at which they boil but it is also desirable to have lower boiling point materials in the mixture. Such lower boiling point materials tend to keep the viscosity down at lower temperatures but boil off as heat is applied and thus do not unduly lower the viscosity at higher temperatures at which the viscosity of the re.- maining constituents is necessarily less because of their increased temperature. Thus not only is it desirable to have mono-alkyl aryl compounds present, but other low boiling point materials, for example, coal tar products such as naphthalene or coal tar naptha may be. added for the purpose of furnishing one or more lower boiling point constituents in the vehicle or lowering the viscosity thereof at ordinary temperatures. Likewise alkyl aryl compounds having lower boiling points and possibly lower viscosities also, may be added. Proportions of these materials cannot be conveniently given here, for they may vary Widely in accordance with the type of Work to be. done and particularly in accordance with the manner in which the fusible coating material is to be applied. In spraying or dipping, for example, a

considerable amount of material of low viscosity I may need to be incorporated in the vehicle to provide the necessary fluidity. In stenciling or brushing, however, the coating composition may often be relatively viscous and at times even pasty in nature.

As an example of one type of coating composition that may be advantageously used in ornamenting glass bottles and the like there may be used as the vehicle a mixture of isomeric monoand poly-amyl naphthalenes having a boiling range spread between 280-39() C. This boiling range may be and preferably is extended downward to around C. by the addition of naphthalene, coal tar naphtha or other lower boiling point constituents of that general nature. The

viscosity at ordinary temperatures is preferably adjusted by selecting a lower boiling point constituent that will combine with the amyl naphthalenes to give the desired viscosity. Approximately 0.25 pound of this vehicle. is mixed with each pound of the fusible coating material to be used.

, The coating material ordinarily is comprised of an easily fusible finely ground glass but may be comprised of any other type of fusible ceramic material desired. One type of glass which is commonly used as a fusible coating material is comprised of 65-75% PbO, around 29% B203 and smaller'amcunts of silica, alumina, soda, potash,

etc. A pigment of any color may be incorporated in the glass. The glass may be fused, crushed, ground finely, sieved to remove oversize particles, and dispersed in the vehicle.

The mixture of ground glass and vehicle is applied to glass and heated to fuse the ground glass into position thereon in the usual manner. The ground glass vehicle composition may also-be applied to metal or to ceramic material such as pottery or dishes and fused on any one of these surfaces in a similar manner. The advantages of a decoration so applied are rather obvious. The coating is far more. permanent than coatings of any other type, is highly attractive if properly applied and the object upon which it is placed can be washed or cleaned without any danger of injury to the coating. In fact, when the coating is applied to metal it acts definitely to protect the surface against attack by the weather or by chemical agents.

Amyl naphthalenes have been mentioned specifically as applicable according to the principles of this invention and these compounds have been found to be especially well suited for the purpose.

It is not the intention, however, to limit the'presa ent invention to use of amyl naphthalenes, but it is intended to include all other alkyl aryl compounds of the same general nature and characteristics, for it is quite apparent that they may be used according to this invention with at least some degree .of satisfaction. 7

As a few examples of other compounds that are usable and as some indication of the types of compounds the use of which is included within scope of this invention, there may be mentioned in addition to the amyl naphthalenes: amyl benzenes, amyl anthracenes lauryl benzenes, tetradecyl toluenes, amyl diphenyl and the corresponding ethyl, propyl, butyl and hexyl compounds.

Even such compounds as diamyl diphenyl ether, amyl phenyl amyl ether and diamyl phenol may be used with satisfactory results; These latter compounds are formed incidentally in the manufacture of alkyl phenols by the treatment of olefin material with phenol and sulphuric acid. Thus their use in the above process constitutes an advantageous economic outlet for products which otherwise have'a limited market.

Any of the compounds mentioned may be mixed in any proportion found to be desirable with any of the other alkyl aryl compounds or with any of the lower boiling point compounds suggested,

to give a mixture that will function satisfactorily,

that is, evaporate at the desired rate and have the desired viscosity. This is a problem of compounding as distinguished from the inventive concept that the amyl naphthalenes and similar compounds or mixtures thereof will function as vehicles, evaporating completely within the desired temperature range and leaving no stains or discolorations in the fused coating.

The composition of the fusible material and of the pigment, and the compounding and preparation of these ingredients is also variable at the will of those who practise this invention since the principles thereof apply regardless of the type of fusible material and pigment used. Likewise the invention is not dependent upon whether the coating is applied to glass, other ceramic material or metal or whether the coating is applied to the entire object to be coated or merely to a small portion thereof as a decoration or marking.

I claim:

1. A composition for forming a fused coating comprising a vehicle including a compound containing at least one aryl nucleus and at least one alkyl group directly attached to the aryl nuclcus and boiling at around 280 to 390 C'., and a finely divided fusible ceramic material dispersed in said vehicle.

2. A composition for forming a fused coating comprising a vehicle including a compound chosen from the class consisting of diaryl ethers, alkyl aryl ethers, and aryl hydroxy compounds, which compounds have been substituted in at least one of their aryl nuclei by alkyl radicals, and which compounds are capable of being volatilized and driven off from the remainder of the composition at temperatures approximating 280 to 390 0. without imparting any color to the remainder of the composition, and a finely divided fusible ceramic material dispersed in said vehicle.

3. A composition for forming a fused coating comprising a vehicle consisting of a naphthalene compound having an alkyl radical substituted for nuclear hydrogen and being capable of distillation at temperatures of around 280 to 390 C. without carbonization, and a finely divided fusible ceramic material dispersed in said vehicle.

4. A composition for forming a fused coating comprising a vehicle including an aryl hydrocarbon having alkyl radicals substituted for a plurality of nuclear hydrogen atoms and being capable of being volatilized at temperatures of 45 around 280 to 390 C. without leaving an appreciable colored residue, and a finely divided fusible ceramic material dispersed in said vehicle.

5. A composition for forming a fused coating comprising a vehicle including a naphthalene hydrocarbon having a plurality of alkyl radicals substituted for a plurality of nuclear hydrogen atoms and capable of being distilled from the remainder of the composition at temperatures of around 280 to 390 C. without imparting a color to the remaining composition, and a finely divided fusible ceramic material dispersed in said vehicle.

6. A composition for forming a fused coating comprising a vehicle including an aryl compound having a plurality of amyl radicals substituted for nuclear hydrogen atoms thereof and boiling in the general range of 280 to 390 C., and a finely divided fusible ceramic material dispersed in said vehicle.

7. A composition for forming a fused coating comprising a vehicle including an amyl naphthalene, and a finely divided fusible ceramic material dispersed in said vehicle and adapted to form the coating.

8. A composition for forming a fused coating comprising a vehicle including a poly-amyl naphthalene, and a finely divided fusible ceramic material dispersed in said vehicle and adapted to form the coating.

9. A composition for forming a fused coating comprising a vehicle including a mixture of amyl naphthalenes, and a finely divided fusible ceramic material dispersed in said vehicle and adapted to form the coating.

10. A composition for forming a fused coating comprising a vehicle including a mixture of amyl naphthalenes and an organic compound having a lower boiling point, and a finely divided fusible ceramic material dispersed in said vehicle and adapted to form the coating.

11. A composition for forming a fused coating comprising a vehicle including a mixture of amyl naphthalenes and naphthalene, and a finely divided fusible ceramic material dispersed in said vehicle and adapted to form the coating.

12. A composition for forming a fused coating comprising a vehicle including amyl naphthalene and naphthalene, and a finely divided fusible ceramic material dispersed in said vehicle and adapted to form the coating.

JOSEPH J. SCHAEFER.