US2224291A - Modified lacquer and varnish diluent - Google Patents

Description

Patented Dec. 10, 1940 UNITED STATES 2,224,291 e '7 H e e PATENT Ferries MODIFIED LACQUER ANl) ,VARNISH DILUENT;

Theodore R. Donlan, Roselle, N. J.,' assignor to Standard Oil Development Company, a corpora-' tion of Delaware No Drawing. Application February 3, 1937,

Serial No. 123,866

4Claims. (01.134 19 2 component or improved diluent consisting of petroleum hydrocarbons containing activators.

Nitrocellulose lacquers usually require an effective solvent which evaporates slowly and prevents blushing. These solvents, comprising various alcohols, ethers, ketones, esters, etc. are very costly and, therefore, are generally used in presence of a large quantity of diluent or non-solvent which, when added to the solution, does not cause the nitrocellulose to precipitate. The diluents generally used are the coal-tar hydrocarbons, particularly toluene and xylene. Benzene may also be used under certain conditions.-

These aromatic hydrocarbons possess certain inherent disadvantages which it would be desirable to eliminate if possible. In the first place the aromatics are notoriously toxic and, therefore, particularly objectionable when used for household and interior purposes. Furthermore, the great demand for these products has greatly increased their cost, a factor which must be taken into consideration in connection with their use. In case of war, they will be diverted in large quantiites from the more peaceful applications to 3 the manufacture of high explosives, thus enhancing their cost still more.

It has previously been proposed to use pe-' troleum hydrocarbons or naphthas in place of these aromatic hydrocarbons as the petroleum 40 derivatives are not toxic, are cheaper to manu facture, and would not be diverted for war-time purposes to the same extent, but it is generally recognized throughout the lacquer industry that they are poor substitutes for the coal-tar hydro- 45 carbons because of the fact that they cannot be added to the lacquer solution to any great extent Without precipitating the nitrocellulose.

One object of this invention, therefore, is to prepare diluents for cellulose lacquers which do 50 not possess any of the inherent disadvantages of either the coal-tar hydrocarbons or the petroleum naphthas, and which further will have exceling diluting powers equal to or greater than either the coal-tar hydrocarbons or the petroleum hydrocarbons hertofore used.

It has already been propsed to use cracked v petroleum hydrocarbons alone or with the addition of monochlorobenzene or of certain alcohols as improved diluents. The use of monochlorobenzene provides the toxic feature mentioned, While the use of alcohol is expensive and also increases the viscosity of the product. Small quanl0 tities of alcohol actually reduce the viscosity of the solution but larger quantities, particularly the amount (not lessthan necessary to activate the hydrocarbons, cause an increase in the viscosity of the resulting lacquer.

The chief embodiment of this invention comprises the activation of petroleum hydrocarbons by the addition thereto of suitable acetates and/or ketones plus alcohols. The alcohols added are in much-smaller proportions than hitherto used (less than 10%), and therefore do not cause the incerase in viscosity usually noticed. It is"preferred'to use,,as the base stock those petroleum hydrocarbons which have a high kauri butanol solvent power of at least 50 as determined by Baldeschwieler, Troeller and Morgan (Ind. Eng. Chem; (anal) v. 7:3'74-7 (1935)). These hydrocarbons are generally prepared by the hydrogenation of the'extract obtained in the refining of petroleumoils with sulfur dioxide or by the hydrogenation of cracked cyclic stock, which contains a largequantity of unsaturated hydrocarbons -These are generally known as hydrogenated naphthas'. Suitable activators include ethyl, propyl, butyl, and amyl acetates, ketones, and alcohols. Isopropyl acetate, secondary amyl acetate, secondary butyl acetate, methyl butyl ketone, methyl"isobutyl ketone, methyl ethyl ketone, isopropyl alcohol, secondary butyl alcohol and secondary amyl alcohol are a few specific examples of activators. With the proper cut of hydrogenated naphtha and the proper evaporating acetate and/or ketone-plus alcohol, diluents can be prepared which will equal or better the dilution properties of the coal-tar hydrocarbons and at the same time possess none of their inherent disadvantages. For example, the following blend has diluting'properties very similar to toluene: I .50

' Per cent Hydrogenated naphtha (boiling range --130 C.) i 90 Secondary butyl-'acetate 6 Secondary butyl'alcoholn'; 4 55,;

of normal butyl acetate.

Methyl normal butyl ketone may be substituted for the secondary butyl acetate with somewhat better diluting results.

There are certain tests in the lacquer industry which give results classifying as to solvent power the various materials used. Such a test is the Diluting Power, which gives the amount of any diluent, such as toluene or naphtha, tolerated by a solution of nitrocellulose in normal butyl acetate or in ethyl acetate. This ratio is determined by dissolving two grams of dry -sec. viscosity regular soluble nitrocellulose in 20 cc. 85-88% normal butyl acetate and titrating at 25 C. with the diluent in question until the nitrocellulose precipitates, and substituting the results in the equation: Diluting power=cc. diluent/cc. solvent (20).

The following table shows the diluting power of various percentages of secondary alcohol, secondary butyl acetate, and hydrogenated naphthat Percent by volume Hydrogenated naphtha 80 90 90 94 92 90 94 Secondary butyl alcohol. 20 10 3 4 4 2 Secondary butyl acetate 5 3 4 6 4 Diluting power 4. 8 3.6 3. 6 3.0 3. 3 3. 7 3.0

"The percentage composition in column six has an evaporation rate close to that of toluene and can be used as a diluent in lacquer formulae with equally good results.

Another test used is the Dilution Ratio, which gives the amount of toluene tolerated by a solution of nitrocellulose in any solvent, such as normal butyl acetate or any combination of materials that will dissolve nitrocellulose. This ratio is determined by dissolving two grams of dry -sec. viscosity regular soluble nitrocellulose in 20 cc. of the solvent in question and titrating at 25 C. with toluene, until the nitrocellulose precipitates, and substituting the results in the equation: Dilution ratio cc. toluene/cc. solvent (20) Any diluent which approaches the dilution ratio of normal butyl acetate possesses a high diluting power. From this it can be seen that the diluting power of toluene is the dilution ratio When hydrogenated naphtha is used in place of coal-tar hydrocarbons in certain formulae, the-dilution ratio immediately drops, but when a hydrogenated naphtha is mixed with a small amount of acetates and/or 'ketones plus alcohols possessing about the same evaporation rates as the coal-tar hydrocarbons and added to the formula as a diluent, the dilution ratio immediately rises to such an extent that in certain cases the resulting blend is a better diluent than the coal-tar hydrocarbons usually used.

The effect of using toluene, hydrogenated naphtha with and without activators and diluents on the dilution ratio of certain lacquer formulae is shown in the following chart. The formulae chosen represent the two extremes in lacquer formulation, i. e., lacquer formulae usually contain varying amounts of normal butyl acetate and ethyl acetate. This is so because of cost considerations, evaporation rates, blush resistance, etc. It is, however, equally true that blends of ethyl acetate and ethyl alcohol are used for certain purposes. Cost considerations, however, must be given to the fact that ethyl acetate shows very poor solvent properties in the pres- Similar composition as in Formula No. 1 containing hydrogenated naphtha activated 'by the addition of 6% secondary butyl acetate and 4% secondary butyl alcohol.

Dilution ratio .80

Formula No.2

Per cent Toluene 60 Ethyl alcohol 10 Ethyl acetate 30 Dilution ratio 1.05

Similar composition as in Formula No. 2 containing hydrogenated naphtha as diluent.

Dilution ratio .20

Similar composition as in Formula No. 2 containing hydrogenated naphtha activated by the addition of 6% secondary butyl acetate and 4% secondary butyl alcohol.

Dilution ratio .60

Formula No. 3

Per cent Toluene 60 Isopropyl alcohol 10 Isopropyl acetate 30 Dilution ratio .80

Similar composition as in Formula No. 3 containing hydrogenated naphtha as diluent.

Dilution ratio .20

Similar composition as in Formula No. 3 containing hydrogenated naphtha activated by the addition of 6% secondary butyl acetate and 4% secondary butyl alcohol.

Dilution ratio .60

Formula N0. 4

Per cent Toluene 60 Secondary amyl alcohol 10 secondary amyl acetate 30 Dilution ratio .15

Similar composition as in Formula No. 4 containing hydrogenated naphtha as diluent causes precipitation of the nitro-cotton.

Similar composition as in Formula No. 4 containing hydrogenated naphtha activated by the addition of 6% secondary butyl acetate and 4% secondary butyl alcohol.

Dilution ratio .20

The above formulae show the use of diluents having diluting properties similar to those of toluene. Diluents having properties similar to benzene and xylene may also be prepared by using the proper cut of hydrogenated naphtha and the proper evaporating acetate and/or ketone plus alcohol as activators. For example, the addition of isopropyl acetate and isopropyl alcohol in the same relative proportions as above to the proper hydrogenated naphtha gives a diluent having properties similar to that of benzene. Likewise the addition of secondary amyl alcohol and secondary amyl acetate to the proper naphtha gives a diluent having a dilution ratio similar to xylene. The proper ketones may be used along with or instead of the corresponding acetate.

This invention is not to be limited to the specific examples for it is my intention to claim the invention as broadly as the prior art permits.

I claim:

1. A coating composition comprising nitrocellulose, a solvent therefor, and a diluent containing a substantially pure petroleum hydrocarbon having a kauri butanol value over 50 and a boiling range of 90 to 130 C., 6 to 12% of an acetate of the formula CEECOOR (where R is an alkyl group) and up to 10% of an aliphatic a1- cohol.

2. A coating composition comprising nitrocellulose in solution in a volatile liquid of which a suitable amount is composed of a diluent comprising 80-90% of a substantially pure petroleum hydrocarbon distillate having a kauri butanol value over 40 and a boiling range of 90 to 130 0., 6-12% of an alkyl acetate, and aliphatic alcohol.

3. A coating composition comprising a cellulose derivative, a solvent therefor, and a diluent consisting of a substantially pure hydrocarbon distillate having a kauri butanol value over and a boiling range of 90 to 130 0., up to 10% of an aliphatic alcohol and 6 to 12% of a substance having the generalformula CHr-( -X where X is a radical selected from the group consisting of R and OR; R representing an alkyl radical of 2 to 5 carbon atoms.

4. A composition of matter comprising a cellulose derivative, a solvent therefor and a liquid diluent for cellulose lacquers consisting of to of a substantially pure hydrocarbon petroleum distillate having a kauri butanol value over 50 and a boiling range of 90 to C. and of a suitable evaporation rate, 6 to 12% secondary butyl acetate and 4 to 8% secondary butyl alcohol.

THEODORE R. DONLAN.

up to 10%.of an