Water dispersible corrosion inhibitor

Abstract

An environmentally benign and water dispersible corrosion inhibitor is disclosed. The corrosion inhibitor comprises a combination obtained by combining at least one of water dispersible polymers, water soluble silicates, water, additives, among other components.

Description

FIELD OF THE INVENTION

[0002] The field of the invention relates to corrosion inhibitors for reducing the corrosion rate of metallic surfaces.

BACKGROUND OF THE INVENTION

[0003] It is well know in this art to apply one or more inhibitors upon a metallic surface to reduce the corrosion rate. Conventional corrosion inhibitors typically contain components that are environmentally desirable. Such components are partiuarally undesirable when employed in applications wherein the components may be released upon water or other environmentally sensitive areas.

SUMMARY OF THE INVENTION

[0004] The instant invention solves problems associated with conventional methods by providing an environmentally benign and water dispersible corrosion inhibitor. The inventive corrosion inhibitor comprises a combination obtained by combining at least one of water dispersible polymers, water soluble silicates, water, additives, among other components. The inventive composition is typically employed in applications were relatively short term (depending upon the application) corrosion inhibition is desired. The inventive composition and process can also be employed for increasing the effective life of metallic surfaces previously treated to impart relatively long term corrosion protection, e.g., painted metallic surfaces.

DETAILED DESCRIPTION

[0005] The instant invention relates to compositions, and method for applying the composition to reduce dusting and/or corrosion of a metallic surface. The metallic surface can comprise an anchor chain such as that used on commercial and military boats and ships. The chain can comprise detachable links such as those described in U.S. Pat. No. 5,974,779, issued Nov. 02, 1999 in the named of Orscheln et al.; hereby incorporated by reference.

[0006] While the inventive composition can comprise a wide range of components, normally the composition is substantially free of toxic components and those leaving a film or sheen upon water. By “substantially free” it is meant that the composition comprises less than about 10 wt. % and normally about 0 wt. % of such components.

[0007] The inventive method can be employed to apply the inventive composition(s) in order to:

[0008] 1) Use silicates and salt water for corrosion inhibition of metal on ocean vessels or platforms,

[0009] 2) Use polyvinyl alcohol or silicate blends for corrosion control,

[0010] 3) Use polyvinyl alcohol as a rust binder for anchor chain or other metal structure,

[0011] 4) Use silicates as rust binder for anchor chain or other metal structures,

[0012] 5) Use silicate solutions as deck or platform wash using salt water diluent, among other applications wherein it is desirable to inhibit corrosion.

[0013] In one aspect of the invention, the inventive composition comprises at least one of polyvinyl alcohol, ethylene vinyl acetate (and copolymers) thereof, among other water soluble or dispersible and non-toxic polymeric compounds, and water. Normally, the polymeric compound comprises polyvinyl alcohol. The amount of water in the inventive composition normally ranges from about 70 to at least 90 wt. %. If desired, the water can comprise salt water including naturally occurring brackish and ocean/sea water (e.g., water comprising about 5 to at least 7 wt. % sodium chloride). The composition of this aspect of the invention is particularly effective at controlling release of dust and debris from a corroded or rusted surface. If desired, the inventive composition can further comprise at least one de-foaming compound, e.g., a silicon modified dispersion of olefinic solids. The inventive composition can be applied upon an anchor chain (e.g., as the chain is being hoisted and placed into a storage locker upon a boat or ship), in order to reduce, if not eliminate, rust and debris from being released into the air when the anchor is redeployed from the storage locker.

[0014] In a second aspect of the invention, the inventive composition comprises at least one water soluble silicate, e.g., sodium silicate, potassium silicate, among other water dispersible silicates, and water. Normally, the water soluble silicate comprises sodium silicate (e.g., density ratio 3:22). The amount of water in the inventive composition normally ranges from about 70 to at least 90 wt. %. If desired, the water can comprise salt water including naturally occurring brackish and salt water (e.g., water comprising about 5 to at least 7 wt. % sodium chloride). The composition has a relatively high pH that ranges from about 8 to about 12, e.g., normally about 11. In general, the higher the pH the greater the effectiveness of the composition at reducing corrosion. If desired at least one pH modifying compound can be added to the composition, e.g., sodium hydroxide. The composition of this aspect of the invention is particuarally effective at controlling release of dust and debris from a corroded or rusted surface as well as reducing the rate of continued corrosion. The inventive composition can be applied upon an anchor chain (e.g., as the chain is being hoisted and placed in a storage locker), in order to reduce corrosion during storage and reduce, if not eliminate, rust and debris from being released into the air when the anchor is redeloyed from the storage locker.

[0015] The inventive composition can further comprise at least one additive such as defoaming agents, anti-microbial, surfactants, anti-freeze, dyes, thickeners, among other components. Examples of a suitable anti-freeze materials are proplyene glycol, methanol, among others. Using environment friendly materials is desirable for applications wherein the composition directly contacts water. An example of suitable defoaming agent comprise silicone based agents.

[0016] The inventive composition can be prepared by combining the components by using any suitable method. Examples of suitable methods comprise hand mixing, agitation, spray mix heads, among other methods known in the art. The combination rate can be enhanced by heating, e.g., 180 F. for a period of about 30 minutes. In some cases, the composition forms an emulsion.

[0017] The inventive composition can be applied upon a desired surface by using any suitable method. Examples of suitable methods comprise dipping, immersing, spraying, wiping, among other delivery methods known in this art. In some cases, it is desirable to prepare a concentrate or an intermediate comprising all components of the inventive composition except water (e.g., salt water). The intermediate is then combined with a readily available source of water (e.g., ocean water in the case of a marine vessel or structure), and applied upon the desired surface. If desired, the intermediate comprises all of the components wherein only a portion of the water (e.g., tap or potable water) is present and remainder of the water (e.g., salt water) is added in situ prior to usage.

[0018] While the above description has emphasized using the inventive composition on marine applications, the compositions can be employed on piers (e.g., as a wash and protectant for concrete), pipe flanges and joints before or after welding, as water blast additive for pipe or flange cleaning and repair, temporary coatings during shipment of metallic articles and intermediates (e.g., coil steel, rod used for making wire rope and strand, among others), anchor chain lockers, wash for off-shore structures (e.g., oil rigs), among other applications.

EXAMPLES

[0019] The following Examples are provided to illustrate certain aspects of the instant invention and shall not limit the scope of any claims appended hereto. The following Table lists the components that were used to prepare the aspects of the inventive composition test below.

Trade Name	Chemical Composition	Supplier
PQ GRADE G	Sodium silicate solid	PQ Corporation
PQ GRADE N	Sodium silicate liquid	PQ Corporation
AIRFLEX 500BP	Vinyl acetate emulsion	Air Products
AIRVOL 203S	Polyvinyl alcohol	Air Products
VINAC RP 710	Polyvinyl acetate	Air Products
DAPRO U-99	Anionic/non surfactant blend	Elementis
DAPRO DF 3163	Modified polyol foam suppressor	Elementis
DAPRO DF 1161	Silicon modified olefinic solids	Elementis
	dispersion foam suppressor

[0020]

Material    Amount
FORMULATION 1
AIRVOL 203S 101.5 g
H2O TAP     405 cc
Preparation: MIXED ON HOTPLATE STIRRER @ 185° F.
FOR 30 MINUTES
FORMULATION 2
PQ GRADE G  10 g
H2O TAP     390 cc
Preparation: MIXED ON HOTPLATE STIRRER @ 190° F.
FOR 30 MINUTES
FORMULATION 3
AIRVOL 203S 150 g
H2O TAP     350 cc
Preparation: MIXED ON HOTPLATE STIRRER @ 190° F.
FOR 30 MINUTES
FORMULATION 4
PQ GRADE G  20 g
H2O TAP     400 cc
MIXING: MIXED ON HOTPLATE STIRRER @ 208° F.
FOR 30 MINUTES

[0021] The following Table describes the Testing Parameters for the Formulations

DESCRIPTION:		Anchor chain coating for marine applications with
		the primary purpose of eliminating/reducing the
		iron oxide dust generated when anchor is dropped
PARAMETERS:	1.	Spray applied during conventional anchor wash
		down procedures that are employed when anchor
		is hoisted
	2.	Non-flammable.
	3.	Water based to allow coating to be incorporated
		into the current wash down equipment.
	4.	Can not leave oily film or sheen on water as the
		coating will likely go overboard during anchor
		wash down.
	5.	Can not leave long duration foam on water.
	6.	After coating dries, it must dissolve in salt
		water to prevent coating build up which could
		lead to flakes or debris floating on water when
		anchor is deployed or debris clogging chain
		locker drains.
	7.	No environmental hazards or impact.
	8.	Coating concentrate must be able to be diluted to
		working solution strength using sea water as this
		is what the Navy uses for wash down.
	9.	Coating can be applied using commercially
		available equipment.

Testing Parameter Descriptions

[0022] 1. FOAMING: This was a visual observation of foaming characteristics when spray applying the coating/protectant.

[0023] 2. DISSOLUTION TEST: Formula being tested was applied to a bare steel panel and dried. Pigments and tension modifiers can be added to allow for a uniform coating (bare steel having a different surface tension than corroded steel) and to give a visual indication if coating dissolves. Coated panel was partially immersed in a 5% salt water solution. After 2 hours, coating was checked to see if it is or has dissolved. The water was also checked for film, flakes or oily sheen on the surface.

[0024] 3. RUB TEST: 10 light double rubs with a white paper towel on a dry anchor chain link. The amount of rust on paper towel is rated from 0 to 5. 0=no rust evident. 5=rust on paper towel same as amount of rust rubbed off uncoated anchor chain (control).

[0025] 4. SALT FOG: Bare clean chain was coated, allowed to dry and placed into salt fog chamber. The type of chain, coating method, and time in chamber will be noted. Results were compared against uncoated chain of same type (control). Rating is from 1 to 5. 1=more corrosion than control, 2=slightly more, 3=same as control, 4=slightly less, 5=less than control

[0026] 5. HUMIDITY: Bare clean chain was coated, allowed to dry and placed in a 100 F. oven onto a perforated plastic shelf that is directly above a pan of water. Results were compared against uncoated chain of same type (control). Rating is from 1 to 5. 1 =more corrosion than control, 2=slightly more, 3=same as control, 4=slightly less, 5=less than control

TABLE A
FORMULATION EVALUATION
	Trial Number
	001	002	003	004
FORMULATION
COMPONENTS
PQ GRADE G	15
AIRFLEX 500 BP		50
AIRVOL 203S			15
VINAC RP710				15
H2O DISTILLED	100
H2O TAP		50	100	100 HOT
5% SALT WATER
TESTS
DISSOLUTION TEST			DISSOLVED, NO FLAKES,
			FILM OR OILY SHEEN ON
			WATER
FOAMING			FOAMS ON
			SPRAYING
RUST RUB OFF
MIXING	STIRRED BY HAND	STIRRED BY HAND	MIXED ON	STIRRED BY HAND
			HOTPLATE/STIRRER HEAT
			SETTING = 2.5 SPEED = 6
			FOR 30 MINUTES
APPLICATION	DIP COAT, HANGER CHAIN	DIP COAT, HANGER CHAIN	DUST TEST-COATING
			APPLIED USING GARDEN
			SPRAYER SET TO
			8 OZ/GALLON
			DISSOLUTION-
			FOAM BRUSH,
			STEEL PANEL

[0027]

TABLE B
FORMULATION EVALUATION
Trial Number
	005	006	007	008
FORMULATION
COMPONENTS
PQ GRADE G
AIR FLEX 500 BP		0.3
AIRVOL 203S
VINAC RP710
Formulation 1	20	2	80
Formulation 2		1	20
Formulation 3				100
DAPRO U-99		0.07
DAPRO DF 3163	.25	0.07	1	0.5
H2O DISTILLED
H2O TAP	10
5% SALT WATER
TESTS
DISSOLUTION TEST		NO DISSOLUTION
FOAMING	FOAMS BUT DISSPATES
	QUICKLY
RUST RUB OFF			BETTER THAN CONTROL	POOR-SAME AS
			BUT NOT RATED	CONTROL BUT NOT
				RATED
MIXING	MIXED BY HAND	ALL INGREDEINTS ADDED	MIXED BY HAND	MIXED BY HAND
		TO TEST TUBE AND
		SHAKEN BY HAND
APPPLICATION	GARDEN SPRAYER SET AT	FOAM BRUSH, BARE STEEL	GARDEN SPRAYER	GARDEN SPRAYER
	8 OZ/GALLON		SET AT 8 OZ/	SET AT 8 OZ/
			GALLON.	GALLON.
			SALTWATER	SALTWATER
			SOAKED RUSTED	SOAKED RUSTED
			ANCHOR	ANCHOR
			CHAIN COATED	CHAIN. COATED
			WHILE STILL	WHILE STILL WET
			WET
COMMENTS	NO SUBSTRATE COATED,	MIXTURE IS STABLE. THIS	BETTER THAN CONTROL	RELATIVELY HIGH
	FOAMING	WAS TO TEST THE	ON RUB TEST BUT NOT
	OBSERVATION ONLY	STABILITY OF 500 BP IN A	AS GOOD AS USING
		PVA SOLUTION AND IF IT	B001-0005 ALONE.
		ALSO AFFECTED THE	WHEN B0001-0005
		COATING SOLUBILITY	ONLY WAS APPLIED THE
			SAME METHOD AS ABOVE
			WAS USED

[0028]

TABLE C
FORMULATION EVALUATION
	PVA (PolyVinyl Alcohol)
	RATIO STUDY	PVA RATIO STUDY	PVA RATIO STUDY
FORMULATION
COMPONENT
PQ GRADE G
AIRFLEX 500 BP
AIRVOL 203S	100
VINAC RP710
Formulation 1		NEAT	10	10
Formulation 2
Formulation 3
DAPRO U-99
DAPRO DF 3163
DAPRO DF 1161	2
H2O DISTILLED
H2O TAP	300		10	20
5% SALT WATER
TESTS
RUST RUB OFF	MODERATE, BETTER THAN	RATING = 0	RATING = 0	RATING = 1
	008 BUT NOT AS GOOD AS
	USING B001-0005 IN A
	8 OZ/GALLON
	RATIO, NOT RATED.
MIXING	MIXED ON HOTPLATE	NO MIX, APPLIED NEAT	MIXED BY HAND	MIXED BY HAND
	STIRRER @ 190° F. FOR
	30 MIN
APPLICATIONS	DILUTED WITH WATER TO	FOAM BRUSH APPLIED TO	FOAM BRUSH APPLIED TO	FOAM BRUSH
	GIVE A 9 g PVA PER	A DRY RUSTED ANCHOR	A DRY RUSTED ANCHOR	APPLIED TO A
	GALLON DILUTED 009 WAS	CHAIN LINK. DRIED USING	CHAIN LINK. DRIED	DRY RUSTED
	PLACED INTO A GRACO	HEAT GUN	USING HEAT GUN	ANCHOR CHAIN
	SPRAY GUN AND SPRAYED			LINK. DRIED
	ONTO A WET ANCHOR			USING HEAT GUN
	CHAIN THAT HAD
	BEEN IMMERSED IN A
	3% SALT WATER SOLUTION
COMMENTS	SOLUTION HAS THE SAME	STUDY TO DETERMINE THE	STUDY TO DETERMINE THE	STUDY TO
	RATIO THAT WAS	AMOUNT OF PVA NEEDED	AMOUNT OF PVA NEEDED	DETERMINE THE
	ATTEMPTED	TO PRODUCE AN	TO PRODUCE AN	AMOUNT OF PVA
	WITH 008 IN THE 8 OZ/	ACCEPTABLE COATING.	ACCEPTABLE COATING.	NEEDED TO
	GALLON SPRAYER . . .	B001-0005 NEAT	10 g OF B001-0005	PRODUCE AN
		EQUATES TO 2 g	DILUTED WITH 10 cc OF H2O	ACCEPTABLE
		PVA/8 cc H2O	EQUATES TO 2 g OF PVA TO	COATING. . . 10 g
			18 cc H2O	OF B001-0005
				DILUTED WITH
				20 cc OF H2O
				EQUATES TO 2 g OF
				PVA TO 28 cc H2O

[0029]

TABLE D
FORMULATION EVALUATION
	PVA RATIO STUDY	010	011	012
FORMULATION
COMPONENT
PQ GRADE G
AIRFLEX 500 BP
AIRVOL 203S		40	40	40
VINAC RP710
Formulation 1	10
Formulation 2
Formulation 3
Formulation 4				300
DAPRO U-99
DAPRO DF 3163
DAPRO DF 1161		1	1	1
H2O DISTILLED
H2O TAP	52	300	300
5% SALT WATER
TESTS
RUST RUB OFF	RATING = 1	RATING = 1	RATING = 1
SALT FOG		16 HOURS, RATING = 3
MIXING	MIXED BY HAND	MIXED ON HOTPLATE	MIXED ON HOTPLATE	MIXED ON
		STIRRER @ 19O° F. FOR	STIRRER @ 19O° F. FOR	HOTPLATE
		30 MIN	30 MIN	STIRRER @ 190° F.
				FOR 30 MIN
APPLICATION	FOAM BRUSH APPLIED TO	RUB TEST-DILUTED AND	DILUTED AND APPLIED	NOT TESTED
	A DRY RUSTED ANCHOR	APPLIED USING A	USING A PRESSURE
	CHAIN LINK. DRIED USING	PRESSURE SPRAYER TO	SPRAYER TO A
	HEAT GUN	A WET RUSTED ANCHOR	WET RUSTED ANCHOR
		CHAIN LINK THAT HAD	CHAIN LINK THAT
		BEEN IMMERSED IN A 3%	HAD BEEN IMMERSED IN
		SALT WATER SOLUTION.	A 3% SALT WATER
		CHAIN WAS ALLOWED	SOLUTION. CHAIN
		TO AIR DRY.	WAS ALLOWED TO AIR
		SALT FOG-DILUTED AND	DRY.
		DIP APPLIED TO BARE
		CLEAN HANGER CHAIN
		AND ALLOWED TO
		DRY THEN PLACED INTO
		SALT FOG ALONG WITH
		AND UNCOATED HANGER
		CHAIN
COMMENTS	STUDY TO DETERMINE THE	DILUTED WITH 900 cc H2O	DILUTED WITH 900 cc OF 5%
	AMOUNT OF PVA NEEDED	EQUATES TO 1 g OF PVA TO	SALT WATER. THIS IS THE
	TO PRODUCE AN	30 cc H2O THE RUB TEST IS	SAME BATCH AS 010 BUT
	ACCEPTABLE COATING . . .	ACCEPTABLE.	SALT WATER IS USED AS
	10 g OF B001-0005		THE DILUENT TO CHECK
	DILUTED WITH 52 cc		IT EFFECT ON SOLUTION
	OF H2O EQUATES		STABILITY AND COATING
	TO 1 g OF PVA 30 cc		PERFORMANCE. SOLUTION
	H2O		IS STABLE AND
			PERFORMANCE IS SAME AS
			010

[0030]

TABLE E
FORMULATION EVALUATION
	Trial Number
	013	014
FORMULATION
COMPONENT
PQ GRADE G
PQ GRADE N (liquid)	100	300
AIRVOL 203S
VINAC RP710
Formulation 1
Formulation 2
Formulation 3
Formulation 4
DAPRO U-99
DAPRO DF 3163
DAPRO DF 1161
H2O DISTILLED
H2O TAP
5% SALT WATER		300
TESTS
RUST RUB OFF	RATING = 0	RATING = 1
SALT FOG		RATING = 1
MIXING	NONE, USED NEAT	MIXED BY HAND
APPLICATION	FOAM BRUSH	RUB TEST-APPLIED
	APPLIED TO DRY	USING A PRESSURE
	RUSTED ANCHOR	SPRAYER TO A
	CHAIN, DRIED	WET RUSTED
	WITH HEAT GUN	ANCHOR CHAIN
		LINK THAT
		HAD BEEN
		IMMERSED IN A
		3% SALT WATER
		SOLUTION. CHAIN
		WAS ALLOWED TO
		AIR DRY SALT
		FOG-APPLIED
		USING A
		PRESSURE
		SPRAYER TO
		CLEAN BARE
		HANGER CHAIN
		AND ALLOWED
		TO DRY
COMMENTS	ANCHOR CHAIN	DILUTED WITH
	HAS SURFACE	SALT WATER
	CORROSION AND
	PITTING BUT
	LITTLE SCALE.
	COATINGS
	SEEM TO SOAK
	INTO THIS
	TYPE OF
	SURFACE.

Claims

1) A composition comprising a combination comprising at least one water dispersible polymer selected from the group consisting of vinyl acetate, vinyl acetate copolymers, vinyl acetate emulsion, polyvinyl acetate and polyvinyl alcohol, water and at least one additive.

2) A composition comprising a combination comprising polyvinyl alcohol, at least one silicon containing foam suppressant, water, and sodium chloride.

3) The composition of claim 1 wherein the water comprises naturally occurring salt containing water.

4) The composition of claim 2 wherein the water comprises naturally occurring salt containing water.

5) The composition of claim 1 further comprising at least one water soluble silicate.

6) The composition of claim 2 further comprising at least one water soluble silicate.

7) The composition of claim 1 wherein said composition has a basic pH.

8) The composition of claim 2 wherein said composition has a basic pH.

9) The composition of claim 1 wherein said water dispersible polymer comprises at least one of vinyl acetate and copolymers thereof.

10) The composition of claim 1 wherein said water dispersible polymer comprises at least one vinyl acetate emulsion.