US2872334A - Asphalt cutback, hard film rust preventive - Google Patents

Description

2,872,334 Patented Feb. 3, 1959 ASPHALT CUTBACK, HARD FEM RUST PREVENTIVE Michael J. Furey, Berkeley Heights, and Roy A. Westlund, Jr., Roselle, N. J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application February 2, 1956 Serial No. 562,948

6 Claims. (Cl. 106-271) This invention relates to improved rust preventive compositions and, more particularly, to improved compositions having utility as solvent-cutback, hard film rust reventives. More specifically, the invention relates to asphalt cutback rust preventive compositions which have been improved in low temperature flaking tendency by inclusion therein of a minor proportion of a microcrystalline wax.

Solvent-cutback, hard film rust preventives are known in the art These are cold-applied compounds used for (1) the protection of metals exposed to a variety of outdoor weather conditions and (2) any general purpose preservation where a dry-to-touch film is desired. These materials generally contain an asphalt diluted with a petroleum solvent. The compounds are fluid in nature and may be applied to the metal surfaces to be protected by dipping, brushing or spraying. Upon evaporation of the solvent, a thin film, usually about 1 to 5 mils thick, remains on the metal parts to serve as protection against weathering, corrosive fumes, and the like. In addition, the protective coating should not flow from surfaces at high temperatures nor flake at low temperatures. When desired, the thin film is easily removed from the metal surfaces by the application of solvents such as petroleum solvents and the like.

Asphalts made by vacuum or steam reduction or by reduction followed by oxidation are desirable as base materials for use in certain solvent-cutback, hard film rust preventives because these asphalts have good storage stability and drying characteristics, give excellent protection, and are readily removed after exposure. They do, however, tend to be excessively brittle at low temperatures, and when cold give an undesirable degreeof flak- .ing or chipping from the metal surfaces being protected. This is particularly undesirable since the portion of-the metal surface exposed is thus available for rusting and corrosion to an even greater degree than completely unprotected surfaces.

It has now been found and forms the object ofthis invention that this undesirable flaking tendency may be inhibited by the inclusion in these solvent-cutback, hard ifilm rust preventive compositions of a minor amount of a microcrystalline wax. This discovery is indeed striking when it is considered that the microcrystalline wax per se is extremely brittle and flakes "quite readily at the test temperatures.

The base material for the compositions'of this inven 'tion comprises from 40 to 70% by weight of an asphalt and from 60 to 30% of .a solvent therefor. The asphalt may be selected from the group of straight reduced asphalts or asphalts prepared by vacuum reduction to a solid'flux with a penetration of less than 200 mm./1O

followed by oxidation, with the latter being preferred. Especially preferred are asphalts which are vacuum reduced to a penetration of less than 70 mm./ and then oxidized to a softening point betweenabout 160 and 170 F. Asphalts prepared by oxidation of a liquid flux are not operable.

The solvent used in preparing the base material may be any of the well-known petroleum solvents having flash points between about and about F. and mid-boiling points ranging from about 300 to about 350 F. with a final boiling point below about 410 F. If it is desired, blends of various solvents having FBP below about 410 F. may be used as the diluent for the asphaltic material.

In accordance with the concept of the instant invention, hard film, solvent-cutback rust preventive compositions were formulated from the following components.

THE ASPHALT COMPONENT Several different asphalts were used in preparing blends in accordance with this invention.

Asphalt A This asphalt is a reduced asphalt made by the vacuum reduction of a Columbian crude. This material, a straight reduced asphalt, had a softening point of about 146 F.

Asphalt B This asphalt was prepared by vacuum reduction of a Venezuelan (Lagunillas) crude to a liquid flux having a flash point of about 500 to 505 F. This flux was then oxidized by air blowing at about 425 F. to a softenin point of to 180 F.

Asphalt C This asphalt was prepared by vacuum reduction of a Venezuelan (Lagunillas) crude to a 500/505 F. flash point liquid flux followed by oxidation by air blowing at about 425 F. to a softening point of 220 to 235 F.

Asphalt A fourth asphalt was prepared by vacuum reducing a Venezuelan (Lagunillas) crude to obtain a solid flux having a 20 to 30 penetration at 77 F. This material was then air blown at about 425 F. to a softening point of 160 to F.

Asphalt E A fifth asphalt was prepared by vacuum reducing a Venezuelan (Lagunillas) crude to a solid flux with a 41 to 60 penetration followed by air blowing at about 425 F. to a softening point of 160 to 170 F.

SOLVENTS In the composition two different solvents were used. Solvent A was a highly refined virgin cut petroleum solvent from a low sulfur parafiinic crude having the following inspections:

Flash point (tag), F 105 Kauri-butanol number 38.0 Aniline point, F 129 50 Percent off at 375 F 90 Final boiling point, F 405 Solvent B was an aromatic petroleum solvent having more than 95% aromatics and having the following inspections:

Flash point, F 107 Initial boiling point, F 300 Percent off at 330 F 50 Percent off at 350 F Final boiling point, F 370 MICROCRYSTALLINE WAX -The waxes used were microcrystalline waxes having a melting point above 170 F. These waxes were prepared by conventional solvent dewaxing of petrolatums or by the solvent dewaxing of the residuum settling out of crude storage tanks. Inspections on these waxes are as follows:

Wax A Color (N. P. 'A.) 3 Flash point F 560 Fire point F 590 Viscosity 210 F SSU 87 Acid No. (ASTM D-974) Saponification No. (ASTM D-94) 0 Penetration (ASTM..D-) mm./ 4 M. P. (ASTM D-127) F 192 Wax B Color (N. P. A.) I. 2 /2 Flash point F 550 Fire Point F 610 Viscosity 210 F SSU 113 Acid No. (ASTM D-974) 0 Saponification No. (ASTM D-94) O Penetration (ASTM D-5) mm./ l0 3 M. P. (ASTM D-127) F 193 Specific, gravity 60 F 0.943

Operable Preferred Component Range (wt. Range (wt.

percent) percent) Asphalt 53. 0-63. 0 29. 34. 0-44. 0 Microwax 1.0-8.0 3. 0-5. 0

In accordance with the concept of the instant invention several blends were prepared. These blends were submitted to the following standard tests for hard film rust preventive compositions.

(1) Film thickness.-This test is conducted as follows: A steel test panel, 2 x 4" x 4;", is finished by polishing with 240 grit aluminum oxide abrasive with cloth or paper backing to a surface finish of 10-20 micro inches (root means square). The panel is then wiped clean and rinsed in boiling naphtha, then in boiling methanol and allowed to cool in a desicator to 77i2 F. The panel is weighed and then immersed for one minute in the test compound maintained at 77i2 F. The panel is withdrawn at the rate of 4 inches per minute and hung to dry in the laboratory. After 24 hours drying the panel 4 is reweighed and the film thickness calculated by the specific gravity weight method.

(2) Drying time.--This test is conducted as follows:

A test panel is coated as in the film thickness test and allowed to hang in the laboratory for 4 hours. At the end of this time the panel is handled, using normal finger pressures. Any transfer of the compound or injury to the film fromhandling fails this test.

(3) Salt'spray test.This test is conducted as follows:

Steel test panels are prepared and coated as in the film thickness test and dried for 24 hours in the laboratory. The panels are then placed in a salt spray cabinet conforming to Method 4001.1 of Federal Specification VV-L-791E and exposed for 14 days. At the end of this time the panels are removed, cleaned with solvent, and examined for rust. Any panel showing no more than 3 corrosion spots, no one of which is larger than 1 mm. in diameter, passes this test. Corrosion within A" of the panel edges is not considered in this evaluation.

(4) Weather-O-Meter test.-This testis conducted as follows:

Steel test panels are coated and dried as for the salt spray test. They are then exposed to the test described in Method 615.1'of Specification TT-P-141 for 1200 hours. At the conclusion of the test the coating is removed and the panel examined for signs of-rust. Corrosion within A of the panel edge shall be disregarded. Any panel showingno more than 3 corrosion spots, no one of which is larger than 1 mm. in diameter, passes the. test.

(5) Low temperature adhesion test.This test is conducted as follows:

- Panels are coated as in the film thickness test and dried for 24 hours. The panel is then cooled to 0 F. for one hour and 4 parallel scratches approximately A5" apart and one inch long made on the film with the scratch tool. Four similar scratches shall be made perpendicular to the first four. Chipping of the coating extending more than 19, from either side of the scratch marks shall be considered a failure. The scratch tool consists of four razor blades held parallel and /e apart by a metal holder.

(6) Thirty-day storage test-This test is conducted as follows:

Steel panels are coated'and film thickness measured as in the first test above. The compound is then stored in the laboratory at 77i5 Fffor 30 days. At the end of this time the compound is mixed by rolling a tightly sealed 0.9 full can at approximately R. P. M. for 5 minutes. A second set of panels are then coated as before and the film thickness measured. Any increase in film thickness exceeding 15% fails the storage test.

In Table I below, there is set out the composition of these blends and the test results.

TABLE I.HARD FILM SOLVENT OUTBACK RUST PREVENTIVES Blend No Composition (wt. percent) Asphaltic Material:

Asphalt A (146 F. S. P.) Asphalt B F.I180 F. S. P.) Asphalt 0 (220 F./235 F. S. P.) Asphalt D (160 F./ F. S. P.) (from Solvent:

- Solvent A (405 F. FBP) Solvent B (370 F. FBP) can Microwax:

Wax A Wax B Test Results:

Film Thickness (mils) Drying Time (4 hours) Salt Spray (14 days) Weather-O-Meter (1,200 hrs.) Low Temp. Adhesion-flaking (in.). Thirty Day Storage 3. 0 Pass Pass 6 Pass 3. 0 Pass Pass Pass 3. 0 Pass Pass Pass .4. 0 Pass Pass '3. 0 Pass Pass Pass 4. 0 Pass Pass Pass 2 Pass Pass %2 Pass 7 it 2 2 Pass Pass Pass A careful examination of the data set out in Table I shows the outstanding advantages of the blends prepared in accordance with the inventive concept. It is to be seen that the inclusion of from 3 to 5% of a microcrystalline wax is essential to enable the rust preventive to pass all the tests set out above. In addition, the asphalt must be either a straight reduced asphalt (A) or one prepared by oxidation of a solid flux prepared by reduction (D or E). Addition of the microcrystalline Wax to asphalts prepared by oxidation of liquid fluxes (B or C) gives unsatisfactory products.

One outstanding composition prepared in accordance with the inventive concept has the following components.

55.0 wt. percent reduced and oxidized asphalt (160/ 170 F. S. P.) 36% solvent A 5% solvent B 4% wax A p This composition was tested according to Military Specification MIL-C-16173-A, grade I for solvent cutback rust reventives, hard film. Results of these tests are set out in Table H below:

TABLE II.SPECIFIOATION MIL-O-16173-A TESTS Test Blend Flash Point (100 F. Min.) Pass Removablllty after Exposure Pass Film Thickness (4.0 Mil. Max.) 3. Salt Spray, 14 Day Pass Accelerated Weathering, 1,200 Hours Pass Recovery From Low Temperature..- Pass Sprayahllity 40 F Pass Low Temperature Adhesion (0 Pass Drying Time, 4 Hours Pass Solvent. (410 F. Max. End Point)-.. Pass Corr i n Pass ALLOWABLE LIMITS Immersion:

=l=1.0 rug/cm. 0. 03 =|=5.0 mgJem. 0.00 =|:7.5 lug/em. 0. 01 :l:0.5 !.'|1,g./c1'n. 0. 01 Aluminum i0.2 rug/cm. -0.02 S el =|=0.2n1g./cm. 0.02 Coating =!=1.0 mg./cm. 0.00 =l=5.0 mg./cm. +0.11 Zinc =a7.5 na ems 0.00 Magnesium" 5:0.5 mg./om. +0.02 Aluminum... =|=0.2 mg./cm. 0. 00 Steel 5:02 mgJcmfi. +0.02

It is to be seen that this composition was quite satisfactory in all portions of this test.

To summarize briefly, the instant invention relates to hard film solvent cutback rust preventive compositions. Compositions of the invention comprise from 40.0 to

70.0 wt. percent, preferably from 53% to 63% of a reduced. or a reduced and oxidized asphalt having a softening point between 140 and 250 F., preferably between 160 to 170 F., from about 29.0 to about 59.0 wt. percent of a solvent having a final boiling point of within the range of from 350 to 450 F, preferably from 34.0 to 44.0 wt. percent of a solvent having a final boiling point between about 360 and 410 F., and about 1.0 to 8.0 wt. percent, preferably about 3.0 to 5.0 wt. percent, of a microcrystalline Wax having a melting point above about 175 F. and a penetration of less than 10 mm./l0.

What is claimed is:

1. A solvent cutback hard film rust preventive composition which consists essentially of a blend of from about 53% to about 63% of an asphalt selected from the class consisting of straight reduced asphalts having a softening point of from about F. to about 250 F. and asphalts prepared by reduction to a solid flux having a penetration of less than 200 mm./ 10 at 77 F. followed by oxidation to a softening point of from about 140 F. to about 250 F., about 34% to about 44% of a petroleum solvent having a final boiling point within the range of from 350 to 450 F., and about 3% to about 5% of a microcrystalline wax having a melting point above 175 F. and a penetration at 77 F. less than 10 mm./ 10, said percentages being by weight based on the weight of the total composition.

2. A rust preventive composition according to claim 1 wherein said asphalt is a reduced and oxidized asphalt.

3. A rust preventive composition according to claim 1 wherein said solvent has .a final boiling point of between 360 and 410 F.

4. A rust preventive composition according to claim 1 wherein said asphalt is a reduced asphalt.

5. A solvent cutback hard film rust preventive composition which consists essentially of a blend of about 53% to about 63% of an asphalt prepared by reduction to a solid fiux having a penetration at 77 F. of less than 70 mum/10 followed by oxidation to a softening point of about to F., about 34% to about 44% by Weight of a petroleum solvent having a final boiling point within the range of about 360 to about 410 F., and about 3.0 to 5.0 wt. percent of a microcrystalline wax having a melting point above F. and a penetration at 77 P. less than 10 mm./10.

6. A solvent cutback hard film rust preventive comlposition which consists essentially of a blend of about 55.0 wt. percent of an asphalt prepared by reduction to a solid flux having a penetration at 77 F. of less than 70 mm./ 10 followed by oxidation to a softening point of about 160 to about 170 F., about 41.0 wt. percent of a petroleum solvent having a final boiling point of about 405 F., and about 4.0 wt. percent of a microcrystalline wax having a melting point above 175 F. and a penetration at 77 F. less than 10 mm./10.

References Qited in the file of this patent UNITED STATES PATENTS Schiermeier et al Nov. 6, 1951

Claims (1)

1. A SOLVENT CUTBACK HARD FILM RUST PREVENTIVE COMPOSITION WHICH CONSISTS ESSENTIALLY OF A BLEND OF FROM ABOUT 53% TO ABOUT 63% OF AN ASPHALT SELECTED FROM THE CLASS CONSISTING OF STRAIGHT REDUCED ASPHALTS HAVING A SOFTENING POINT OF FROM ABOUT 140*F. TO ABOUT 250*F. AND ASPHALTS PREPARED BY REDUCTION TO A SOLID FLUX HAVING A PENETRATION OF LESS THAN 200 MM./10 AT 77*F FOLLOWED BY OXIDATION TO A SOFTENING POINT OF FROM ABOUT 140*F TO ABOUT 250* F., ABOUT 34% TO ABOUT 44% OF A PETROLEUM SOLVENT HAVING A FINAL BOILING POINT WITHIN THE RANGE OF FROM 350* TO 450*F., AND BOUT 3% TO ABOUT 5% OF A MICROCYSTALLINE WAS HAVING A MELTING POINT ABOVE 175*F. AND A PENERTRATION AT 77*F. LESS THAN 10 MM./10, SAID PERCENTAGE BEING BY WEIGHT BASED ON THE WEIGHT OF THE TOTAL COMPOSITION.