WO1993008252A1

WO1993008252A1 - Oil removal compositions

Info

Publication number: WO1993008252A1
Application number: PCT/US1992/008061
Authority: WO
Inventors: Kolazi S. Narayanan; Ratan K. Chaudhuri; Robert B. Login; Frank Fusiak
Original assignee: Isp Investments Inc.
Priority date: 1991-10-21
Filing date: 1992-09-21
Publication date: 1993-04-29
Also published as: AU2668192A

Abstract

Oil removal is carried out with a composition comprising: (a) between about 50 and about 95 wt. % of N-methyl pyrrolidone and between about 50 and about 5 wt. % of an N-alkyl pyrrolidone wherein said alkyl group contains from 8 to 14 carbon atoms, or (b) an aqueous solution of a higher-alkyl pyrrolidone, an anionic surfactant, and water.

Description

OIL REMOVAL COMPOSITIONS

There is provided a liquid composition capable of solubilizing and/or removing deposits of oil, grease, wax, carbon, epoxy resins, paint and buffering compounds from a substrate which comprises between about 50 and about 95 wt. % of N-lower alkyl* pyrrolidone and between about 50 and about 5 wt. % of an N-alkyl pyrrolidone wherein said alkyl radical contains from 8 to 14 carbon atoms. It is to be understood that mixtures of the C₈ to C₁₄ alkyl pyrrolidone components can also be used. The preferred composition contains between about 70 and about 85 wt. % N-methyl or N-ethyl pyrrolidone and between about 30 and about 15 wt. % of the higher alkyl pyrrolidone. Optional adjuvants which may be added to the present composition include up to about 5 wt. % of an anionic, cationic, non-ionic or amphoteric surfactant, such as an alkoxylated alcohol, e.g. EMULPHOGENE^®; an alkoxylated phenol, e.g. IGEPAL^® or a salt of an alkoxylated sulfate, e.g. ALIPAL^®, a phosphate ester of an alkoxylated C_g to C₁₂ alcohol, e.g. GAFAC^® or a mixture thereof; up to about 5 wt. % of a corrosion inhibitor, such as e.g. a blend of propargyl alcohol and thiourea e.g. Rodine^® supplied by Amchem Products Inc. or Armohib^® supplied by Akzo Chemicals Inc. and up to about 40 wt. % of a diluent, such as water, a dimethyl imidiazolinone, an alkylene glycol ether or acetate thereof, tetrahydrofurfuryl alcohol, tetramethyl urea, an ethylene, propylene or butylene carbonate, ethyl-3-ethoxy propionate, butyrolactone, a dibasic ester of for example dimethyl adipate, dimethyl glutarate, or dimethyl succinate, etc. Generally, the Brookfield viscosity of the composition should be less than about 2 cps.

* c to C₄ alkyl 3/08252

- 2 - ^•

The present composition can be applied to the substrate as an aqueous solution in which the concentration of the pyrrolidone mixture is between about 50 and about 97 wt. %, preferably between about 90 and about 95 wt. %,- although the undiluted pyrrolidone mixture can also be used in accordance with this invention.

The substrates from which lubricant is removed include all metals as well as glass, ceramic and wood surfaces; however, aluminum, copper, iron, steel and alloyed metal surfaces are most important.

In operation, the composition of the invention is contacted with the lubricant deposit and allowed to act on it for a suitable period of time, depending upon the severity and nature of the deposit and the condition of the substrate. As a general rule, soil is more easily removed from smooth surfaces than from those which are ornate, pitted and scarred. It has been found that contact with the composition of from about 30 seconds to about 48 hours, more often from about 1 to about 10 minutes with ultrasonic agitation, is usually sufficient to satisfactorily remove the above lubricant deposits, except in cases of extremely heavy fouling where immersion over a period of hours may be required.

The pyrrolidone mixture is contacted with the deposit at about ambient^"temperature up to about 10° below the flash point of the pyrrolidone mixture, depending on the nature of the deposit. For example, when cleaning of machined parts having a light lubricant deposit one can employ slightly elevated temperatures; optical lenses can be cleaned at ambient temperature but when used as a cleaning fuel additive, the present degreasing mixture may be subjected to temperatures above 100°C. The high flash points of applicants mixtures generally above 90°C. and in some cases above 100°C. , together with their compatability with kerosene and gasoline permits their use as cleansing additives in motor fuels. - 3 -

EXAMPLE 1

Seven 1 x 2 inch aluminum coupons (1-5) were each immersed for 60 seconds in Ordnance oil* and then drained to permit excess oil to run off. The oil soiled coupons were then immersed in separate cleaning tanks containing the following cleaning compositions which were previously prepared by simple mixing of the components at room temperature.

Wt. % of Component

In Tank #

Coupons

Components 3 4 5 6

N-methyl pyrrolidone 83 88 86 89 93 73 73 N-octyl-pyrrolidone

(SURFADONE LP-100) 10 10 10 10 20 20 GAFAC RS-410 (the phos¬ phate ester of ethoxyl ated decyl alcohol) 2 2 2 2 Triethanolamine 4 4 4 4 IGEPAL CO-630 (ethoxyl- ated nonyl phenol) EMULPHOGENE DA-630 (ethoxylated decyl alcohol)

* a heavy duty cutting oil supplied by Lyondell Petroleum Co. and comprising a hydrotreated heavy naphthenic distillate, an extreme pressure additive, chlorinated aliphatic hydrocarbon and a solvent dewaxed heavy paraffin distillate. The cleaning solutions were maintained at 25°C. and mechanical agitation in the cleaning tank was supplied by a laboratory stirrer. The % of oil removal after 30 seconds coupon immersion was as follows:

Approximate Coupon from Tank # % Oil Removed

1 . 85

2 85

3 75

4 75

5 55

6 85

7 . 85

100% oil removal from coupons 1-4 and 6-7 was achieved within one minute.

Similar results are achieved when N-tetradecyl pyrrolidone is substituted in the above compositions 1-4 and 6-7 for N-octyl pyrrolidone.

The cleaning solution applied to Coupon 5, not only showed poor soil removal but also formed a 2 phase liquid mixture. The formation of the oil phase in this mixture is particularly objectionable since it indicates some oil redeposition upon removal of the cleaning solution.

EXAMPLE 2

Nine 3 5 inch carbon steel coupons were each immersed for 60 seconds in Quaker State 10W40.Motor Oil and then drained to permit excess oil to run off. The soiled coupons were then immersed in 3 gallon Crest Ultrasonic "Vibra-Bar" transducerized tanks equipped with a Genesis "Simultaneous Multifrequency" Ultrasonic generator at full power of 240 watts, 40 kHz at 125°F. and containing the following compositions.

Weight % of Components

Coupons

Components

N-methyl-2-pyrrolidone 100 90 80 60 70 50 50

N-octyl-2-pyrrolidone 100 10 40 15 50

N-dodecy1-2-pyrrolidone 100 20 15 50

Coupons from experiments 1, 2 and 3 were only partially cleaned (approximately 40-80% oil removal) after 3 minutes of immersion. Coupons 4 through 9 were .completely cleaned after 1 minute of immersion and developed a clean water break film after immersion in distilled water.

EXAMPLE 3

Nine soiled optical glass molds used in the manufacture of polycarbonate (CR-39) eyeglass lenses were immersed in the solvent systems of Example 2 with ultrasonics at 125°F. and 170°F. After 5 minutes, the glass molds immersed in solvent blends 4-9 were effectively cleaned of the residual polycarbonate, wax and pitch residues. Solvent blends 1 through 3 were only partially cleaned as determined visual inspection under 40 x magnification.

EXAMPLE 4

The procedure in Example 1 was repeated except that instead of a mechanical stirrer, ultrasonic agitation was employed and the following cleaning solutions were used in the coupon immersion step in place of those used in Example 1.

Weight % of Components

Coupons Components 1 2 3 4 5

N-methyl-2-pyrrolidone 92 50 50 . . 50

Alkoxylated phenol (Igepal CO-530) 3 - . - - 3

GAFAC RE-610 1 - - - 2

Triethanolamine 3 - - - 3

Antarox BL-344* 1 - . - -

Dipropylene glycol monomethyl ether 50

Dibasic Ester** 50 - 92

Gam a-Butyrolactone - - - 50

* a mixture of ethyloxylated hydrophobes, alkylphenols, and an aliphatic polyether

** a mixture of dimethyl succinate, dimethyl glutarate and dimethyl adipate

- 8 - .

In all instances,, only 40-60% of the Ordnance Oil was removed after 5 minutes of immersion. After 15- minutes, cleaning improved to 70-80% removal, but an oil layer developed on the surface of the cleaning solutions which recoated the coupons on their removal from the bath.

EXAMPLE 5

A 10x10 inch wood panel painted on one side with, a 1/32 inch layer of white epoxy paint, is contacted with composition 6 of Example 1 for 5 minutes by applying a sponge saturated with said composition to the painted surface under ambient conditions. After removal of the sponge, the paint layer is peeled off.

BRIEF DESCRIPTION OF THE DRAWINGS

The Figure is a three component phase diagram for N-octyl-pyrrolidone, sodium dodecyl sulfate and water.

In another embodiment of the invention, the composition contains one or more higher alkyl substituted lactams, an anionic surfactant and water. For purposes of this disclosure, the term "higher alkyl" refers to C₆ alkyl or higher and the term "lactams" is inclusive of caprolactam and pyrrolidone. The lactams as shown in Formula I may be used in the invention.

Where = 3, 4, 5 and n < 6. Preferably, the higher-alkyl pyrrolidones of the Formula II are used.

Where n = 6-20, R¹, R" and R'" are H, lower alkyl, alkoxy, cycloalkyl, or aralkyl.

Most preferred are N-octyl-pyrrolidone, N-dodecylpyrrolidone or mixtures thereof.

As the anionic surfactant, alkali metal salts of C₈-C₂₂ aliphatic surfactants such as sodium dodecyl sulfate, sulfonate, alkali metal salts of alkyl aromatic sulfonates, sulfates, and ethoxylated versions of the above, such as the alkylphenyl ethoxylated phosphate esters may be used. The anionic surfactants may form pseudo salts or ion pairs with the higher-alkyl pyrrolidones, and are believed to produce synergistic effects on wetting and surface spreading.

Water is the third ingredient, and the three components should be present in particular proportions. The higher alkyl pyrrolidone should be present at about 0.1-90%, preferably 10-60% by weight. The anionic surfactant should be present at about 0.01-24%, preferably 2-10%.

The oil removal composition may be premixed as a concentrate containing 20-60%, preferably 25-35% of the required water. Typically, the concentrate could be diluted in a 1:10 to 1:100 ratio, concentrate to water to produce the oil removal composition of the invention. The preferred concentrate has 40-60% pyrrolidone and 5-10% anionic surfactant. Optionally, thickeners, foaming agents, defoamers, etc can be added. Referring to the Figure, a phase diagram for the mixture of N-octyl-2-pyrrolidone, sodium dodecyl sulfate and water is shown. As is seen from the diagram, one can solubilize N-octyl-2-pyrrolidone in water at practically any concentration by the addition of the anionic surfactant. Preferably, about 2% anionic surfactant is present. Solubilized N-octyl-pyrrolidone, sodium dodecyl sulfate and water homogeneous solutions are under the curve bounded by points EHIC with these solubilized compositions being particularly suitable for removing oil, grease and other such materials from hard surfaces, quickly and effectively.

Compositions falling within the shaded areas form gels which can be formulated as oil lifting compositions. Such a gel may be placed in a squeeze bottle for direct application ior spot cleaning or diluted with water before use. Compositions falling outside the shaded areas may still be formulated as gels by adding gel forming agents or thickeners such as carboxyl propylcellulose or carboxyl ethylcellulose (KLUCEL H) . The compositions covered by the regions EBFH are particularly suited to forming micro emulsions with hydrophobic compounds.

EXAMPLE 6

6.9 grams of sodium dodecyl sulfate (SDS) , (29% aqueous solution) and 10 grams of N-octy1-2-pyrrolidone (NOP) were added to 83 grams of water. The composition had the following ingredients in weight percent; 10% NOP, 2% SDS and 88% deionized water. To^' 10 grams of this solution was added 0.3 grams of kerosene which immediately formed an emulsion. This mixture was diluted with an additional 60 grams of water yet the kerosene remained completely solubilized and absorbed and could not be seen by the naked eye. COMPARATIVE EXAMPLE 7

To 60 grams of water was added 0.3 grams of kerosene. The kerosene floated on top. No emulsion or micro-emulsion formed.

COMPARATIVE EXAMPLE 8

To 56 grams of water were added 0.3 grams of kerosene and 6.8 grams of sodium dodecyl sulfate. No emulsions formed and small drops of kerosene floated on top of the water.

COMPARATIVE EXAMPLE 9

To 60 grams of water were added 10 grams of N-octyl-2-pyrrolidone and 0.3 grams of kerosene. Again, an oil phase formed on top of the water.

EXAMPLE 10

. A concentrate comprising 6 g. N-ocyl-2-pyrrolidone and 3.5 g. 29% aqueous sodium dodecyl sulfate was diluted by the addition of 350 g. of water. To this was added 2.0 g. of kerosene at room temperature (23°C). The kerosene was completely solubilized and absorbed.

The compositions and results of Examples 6-10 are shown in Table I which demonstrates that the prescribed mixture is useful for absorbing oil or grease in a biodegradable cleaning formulation. /08252

12 -

EXAMPLES 11-15

Five formulations were additionally prepared for testing to remove motor oil stains from a driveway which ranted in age from 7 days to greater than 1 month. Table II shows the five formulations which had varying amounts of N-octyl-2-pyrrolidone (NOP) , sodium dodecyl sulfate (SDS) , the amount and/or presence of sodium dodecyl sulfonate, and the amount and/or presence of N-dodecyl-2-pyrrolidone (NDDP) .

- 13 -

The compositions were poured liberally onto an oil stain and grease stain covering approximately a one square foot area and left to stand for 10-15 minutes. The spot was spray rinsed with water from a garden hose for 1-2 min. and then the water lightly swept with a coarse broom into a drain. The following results were obtained.

Three of these compositions were effective in removing the oil stains from the concrete driveway. Examples 11 and 14 are not as effective in this application due to their low concentrations of active components. However, they are effective in other oil removal applications.

EXAMPLE 16

3 gals of deionized H₂0 were placed in an ultrasonic tank, 1 pt. of the composition of Example 12 (60% NOP, 10% SDS, 30% water) was added and mixed thoroughly until a clear homogenous solution developed. The ultrasonics were set at full power (240 watts, 40 KHz) . A basket with ball bearings containing baked on grease was placed in the bath for five minutes. After removal and rinsing with deionized H₂0, the bearings were rinsed with isoprppanol and then cold air blown dry for ten minutes.

The ball bearings were completely cleaned of grease and oil, and a white surface smut was also removed. The performance was comparable to parts cleaned with a hydrocarbon degreaser at 150°F.

The temperature of the bath was raised to 180-200°F. and the cleaning cycle repeated. However, the bearings were immersed in ultrasonic bath for only 2 ins. The results were similar to the ambient temperature results. A slight phase separation was noted as the solution turned milky white. Cleaning however was excellent. Upon cooling, the solution cleared and the oil and grease rose to the surface. COMPARATIVE EXAMPLE 17

The procedure of Example 16 was used, however, only 1 pt. of 29% aqueous sodium dodecyl sulfate was added to the ultrasonic bath containing deionized H₂0 (3 gal) ; no higher alkyl pyrrolidone was used.

At 75-80°F. , a basket of ball bearings was immersed in the bath for 5 mins. with full ultrasonic power. The cleaning was poor as grease, carbon and white smut remained on the surface of the bearings.

The temperature was raised to 160-180°F. After 5 ins., the bearings appeared visually clean but on inspection with lOx to 4Ox magnification, numerous black and white specks were apparent. The bath was also cloudy.

EXAMPLE 18

100 g. of NOP were added to the bath of Example 17 and, upon mixing thoroughly, the bath cleared, possibly indicating that the oil and grease micro-emulsified. The cleaning steps were repeated using the mixed bath and additional sets of ball bearings. In both instances, the ball bearings were completely clean and free of smut and carbon deposits. Under lOx - 4Ox magnification, no black or white specks were apparent.

EXAMPLE 19

Two microscope glass slides were coated with beeswax which was allowed to solidify. The slides were immersed in the mixed bath of Example 18 at a temperature of 150°F. After 1 min. , the slides were completely cleaned with no visible residue. EXAMPLE 20

To approximately 3 gallons of water was added 100 •g. of the composition of Example 12 with thorough mixing. 1/2 of a barbecue grill caked up with grease and carbonized residues was placed in the bath. After immersing in the liquid for 2 hours, without any agitation, the liquid was rinsed off with water using a garden hose. The grease was completely removed from the grill. However, deposits of carbonized residues persisted. The liquid appeared uniformly discolored with no distinctive phases. The grease was effectively micro-emulsified.

EXAMPLE 21 -

Seyeral 25 X 74 mm glass microscope slides were immersed into a jar of liquified bacon grease (70°C), removed and the excess allowed to drain-off. The slides were placed in a freezer at -15°C. to facilitate solidification of the grease on the slides. The slides were removed from the freezer after 30 mins. and placed in a desiccator for 1 hour to remove condensed water from the slides. The slides were then immersed in (A) water, (B) water with 0.4% of a commercial dishwashing detergent (CDO) containing a semi-polar non-ionic detergent, an alkaline earth metal salt of an anionic detergent and an a ino butylbotaine and (C) water with 0.04% composition of Example 12. The solutions were non-agitated and maintained at 45°C. to simulate household warm water. After 15 mins., the slides were removed and excess H₂0 was allowed to drain-off. The slides were placed in a desiccator overnight. The results are shown in Table IV. - 17 -

Slides removed from solutions B and C appeared clean, shiny and free from grease. The cleaning baths were hazy in the following order: B<C<A. Over 95% removal is considered excellent performance.

Claims

ft,mo,„ 93/08252- 18 -WHA IS CLAIMED IS:

1. A liquid degreasing and paint stripping composition containing between about 50 and about 95 wt. % of N-lower alkyl pyrrolidone and between about 50 and about 5 wt. % of an N-C₈ to C₁₄ alkyl pyrrolidone, optionally up to 5 wt. % of a surfactant.

2. The composition of claim 1 wherein the composition comprises between about 70 and about 85 wt. % of N-lower alkyl pyrrolidone and between about 30 and about 15 wt. % of N-Cg to C₁₄ alkyl pyrrolidone.

3. The composition of claim 1 wherein said N-lower alkyl pyrrolidone is N-methyl pyrrolidone, said N-Cg to C₁₄ alkyl pyrrolidone is N.-octyl pyrrolidone, or said N-C₈ to C₁₄ alkyl pyrrolidone is N-dodecyl pyrrolidone.

4. An aqueous cleaning composition for removing oil or grease from a hard surface comprising 0.01-90% higher alkyl lactam, 0.01-24% anionic surfactant and water.

5. The cleaning composition of claim 4 wherein the higher alkyl substituted lactam is of the following formula:

Where m = 3, 4, 5 and n < 6, - 19 -

6. The cleaning composition of claim 4 wherein the higher alkyl substituted lactam is a pyrrolidone of the following formula:

where n = 6-20, R¹, R" and R'" are H, lower alkyl, alkoxyl cycloalkyl, or aralkyl.

7. The cleaning composition of claim 6 wherein the higher alkyl substituted pyrrolidone is N-octyl-2-pyrrolidone, N-dodecyl-2-pyrrolidone, or N-octadecyl-2-pyrrolodione, and mixtures thereof.

8. The cleaning composition of claim 4 wherein the anionic surfactant is an alkali metal salts of C₈-C₂₂ aliphatic surfactants such as sodium dodecyl sulfate, sulfonate, alkali metal salts of alkyl aromatic sulfonates, sulfates, and ethoxylated versions of the above, such as the alkylphenyl ethoxylated phosphate esters may be used.

9. The cleaning composition of claim 4 wherein the anionic surfactant is an alkali metal salt of a C₈-C₂₂ aliphatic surfactant, wherein from 20-70% higher alkyl substituted lactam, and wherein from 1-20% anionic surfactant is present.

10. A concentrate of an aqueous cleaning composition for removing oil or grease from a hard surface comprising 40-65% higher alkyl substituted cyclic lactam, 5-20% anionic surfactant and 15-55% water.