WO2000054614A2 - Anti-static, non-sparking coatings for explosive environments - Google Patents

Anti-static, non-sparking coatings for explosive environments Download PDF

Info

Publication number
WO2000054614A2
WO2000054614A2 PCT/US2000/007252 US0007252W WO0054614A2 WO 2000054614 A2 WO2000054614 A2 WO 2000054614A2 US 0007252 W US0007252 W US 0007252W WO 0054614 A2 WO0054614 A2 WO 0054614A2
Authority
WO
WIPO (PCT)
Prior art keywords
coating
static
sparking
polymer
coatings
Prior art date
Application number
PCT/US2000/007252
Other languages
French (fr)
Other versions
WO2000054614A3 (en
Inventor
W. Thor Zollinger
Kerry Klingler
Charles B. Isom
Scott Bauer
Original Assignee
Solex Robotics Systems, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Solex Robotics Systems, Inc. filed Critical Solex Robotics Systems, Inc.
Priority to AU58659/00A priority Critical patent/AU5865900A/en
Publication of WO2000054614A2 publication Critical patent/WO2000054614A2/en
Publication of WO2000054614A3 publication Critical patent/WO2000054614A3/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/24—Electrically-conducting paints
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
    • C06B45/12—Compositions or products which are defined by structure or arrangement of component of product having contiguous layers or zones
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D127/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers
    • C09D127/02—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment
    • C09D127/12—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms

Definitions

  • This invention generally relates to a coating, and a method of producing a coating, that can be used in explosive environments. More specifically, this invention relates to an anti-static, non-sparking coating that can be applied to various components such that the components may be safely used in corrosive and explosive environments.
  • plastics enclosures or plastics parts of enclosure for example, for Group IIA and IIB apparatus to a maximum of 100 cm 2 except that this may be increased to a maximum of 400 cm 2 if the exposed areas of plastics are surrounded by conductive earth- grounded frames); or (c) by virtue of the size, shape, and lay-out, or other protective methods, such that dangerous electrostatic charges are not likely to occur.
  • the present invention is directed to an anti-static, non-sparking coating that can be applied to various components such that the components may be safely used in corrosive and explosive environments.
  • Fluorine-containing polymers or fluoropolymers
  • fluoropolymers are an important class of polymers and include for example, fluoroelastomers and fluoroplastics. Within this class are polymers of high thermal stability and usefulness at high temperatures, and extreme toughness and flexibility at very low temperatures. Many of these polymers are almost totally insoluble in a wide variety of organic solvents. See, for example F.W. Billmeyer, Textbook of Polymer Science, 3rd ed., pp 398-403, John Wiley & Sons, New York (1984). These polymers, however, cannot be used in explosive environments because they encourage the accumulation of electrostatic charges on the surfaces of the coated component.
  • coatings that are used in explosive environments would have low resistivities to ward off electrostatic charges.
  • a "perfect" conductor would have zero resistivity and a "perfect” insulator an infinite resistivity.
  • Metals such as copper and gold
  • alloys such as manganin and nichrome
  • semiconductors such as carbon or germanium
  • the resistivities of insulators exceed those of metals by a factor of the order of 10 22 .
  • Carbon powder was added to the coatings to increase the conductivity. Carbon percentages from about 10% to about 50% passed the certification testing with resistivities less than 1 G ⁇ . The carbon powder enhances the ability of the polymer
  • Halar is a trademark of Ausimont of Morristown, New Jersey for ethylene-chlorotrifluoroethylene (ECTFE).
  • Halar coatings have favorable characteristics that include: resistance to strong acids, such as sulfuric, nitric, hydrochloric, and hydrofluoric, over a wide temperature range; the ability to handle powder bleaching agents, such as sodium hypochlorite; resistance to strong bases, such as sodium hydroxide and potassium hydroxide; and resistance to strong polar solvents, such as n-methyl pyrrolidone and dimethyl formamide, that would dissolve other polymers.
  • Halar fluoropolymers are advertised as incapable of being dissolved by any known solvent up to 300°F.
  • Halar fluoropolymer exhibit extraordinary smoothness.
  • Halar polymers cannot be certified for explosive environments.
  • a series of five sample coatings were developed with graphite being added to the fluoropolymer coating in percentages ranging from about 10%> to about 50%>. The graphite was added to the coating to increase its conductivity and resistance to building up static. The same insulation resistance tests were run on each sample and the results were all well below the 1.0 x 10 10 required.
  • the fluoropolymer coating used on the submergible vehicle has 10%> graphite added to it.
  • the present invention describes a method and materials for coating components for use in hazardous locations that are capable of meeting Class I Division 1 certification standards that are required for safe use within an explosive environment, as specified in the National Electric Code.

Abstract

There is disclosed an anti-static, non-sparking coating that can be applied to various components such that the components may be safely used in explosive environments.

Description

INTERNATIONAL PATENT APPLICATION
Entitled
ANTI-STATIC, NON-SPARKING COATINGS FOR EXPLOSIVE
ENVIRONMENTS
Field of the Invention
This invention generally relates to a coating, and a method of producing a coating, that can be used in explosive environments. More specifically, this invention relates to an anti-static, non-sparking coating that can be applied to various components such that the components may be safely used in corrosive and explosive environments.
Background of the Invention
In the chemical, petrochemical, and refinery operations business, a myriad of components are used for testing, inspecting, cleaning, and operating various process vessels, storage tanks, reactor vessels, and the like. The metal structure of theses components constitutes a conducting path allowing the flow of electrostatic charges generated by the movement of gases, vapors, dusts, or liquids contained in the vessels and tanks. These components, however, have non-conducting elements that resist this flow by encouraging the accumulation of electrostatic charges on their surfaces. The same is true of metal surfaces coated with polymer based coatings, since the polymer acts as a very thin non-conducting element. These polymers, however, can withstand the harshest chemical environments, and are needed because the components on which they are applied would otherwise corrode, degrade, or become inoperable. While these coatings are suitable for corrosive environments, these coatings are subject to static buildup, which precludes their use in explosive environments.
In fact, several standards and regulations have been promulgated to provide guidelines as to acceptable electrostatic levels for a variety of materials or enclosures. One such standard is European Standard EN 50014, Section 7.3.2. This standard requires that enclosures shall be so designed that under normal conditions of use, maintenance, and cleaning, danger of ignition due to electrostatic charges are avoided. This requirement can be satisfied by either of the following: (a) by suitable selection of the material so that the insulation resistance of the enclosure does not exceed 1 GΩ
at 23+2°C and 50±5% relative humidity; (b) by limitation of the surface area of
plastics enclosures or plastics parts of enclosure (for example, for Group IIA and IIB apparatus to a maximum of 100 cm2 except that this may be increased to a maximum of 400 cm2 if the exposed areas of plastics are surrounded by conductive earth- grounded frames); or (c) by virtue of the size, shape, and lay-out, or other protective methods, such that dangerous electrostatic charges are not likely to occur.
Because of these types of regulatory standards, there is a need for a new coating that is anti-static and non-sparking that can be applied to various components, such that the components may be safely used in corrosive and explosive environments.
Summary of the Invention
The present invention is directed to an anti-static, non-sparking coating that can be applied to various components such that the components may be safely used in corrosive and explosive environments.
The foregoing has outlined rather broadly the features and technical advantages of the present invention so that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily used as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
Detailed Description of the Invention
Many of the components used for testing, inspecting, cleaning, and operating various process vessels, storage tanks, reactor vessels, and the like are coated with chemically-resistant polymers such as fluoropolymers. Fluorine-containing polymers, or fluoropolymers, are an important class of polymers and include for example, fluoroelastomers and fluoroplastics. Within this class are polymers of high thermal stability and usefulness at high temperatures, and extreme toughness and flexibility at very low temperatures. Many of these polymers are almost totally insoluble in a wide variety of organic solvents. See, for example F.W. Billmeyer, Textbook of Polymer Science, 3rd ed., pp 398-403, John Wiley & Sons, New York (1984). These polymers, however, cannot be used in explosive environments because they encourage the accumulation of electrostatic charges on the surfaces of the coated component.
Ideally, coatings that are used in explosive environments would have low resistivities to ward off electrostatic charges. By way of explanation, a "perfect" conductor would have zero resistivity and a "perfect" insulator an infinite resistivity. Metals (such as copper and gold), alloys (such as manganin and nichrome), and semiconductors (such as carbon or germanium) have the lowest resistivities and are the best conductors. The resistivities of insulators (such as glass, Teflon, and wood) exceed those of metals by a factor of the order of 1022.
A number of polymer based coatings used in caustic chemical environments were tested prior to modification, and all failed the anti-static tests with resistivities
greater than 85 GΩ's. Exposed surfaces greater than 100 cm2 must have a resistivity
less than 1 GΩ to qualify as static conductive under the certification standards.
Carbon powder was added to the coatings to increase the conductivity. Carbon percentages from about 10% to about 50% passed the certification testing with resistivities less than 1 GΩ. The carbon powder enhances the ability of the polymer
coating to conduct static electricity away from the surface, preventing sparking. Components using this type of material can now be coated for chemical protection and used within potentially explosive environments.
EXAMPLE The initial results of the tests ran on the Halar fluoropolymer coating on a submergible vehicle that can be used in storage tanks measured 8.5 X 1010 Ω and the
maximum allowed was 1.0 X 1010 Ω. Halar is a trademark of Ausimont of Morristown, New Jersey for ethylene-chlorotrifluoroethylene (ECTFE). Halar coatings have favorable characteristics that include: resistance to strong acids, such as sulfuric, nitric, hydrochloric, and hydrofluoric, over a wide temperature range; the ability to handle powder bleaching agents, such as sodium hypochlorite; resistance to strong bases, such as sodium hydroxide and potassium hydroxide; and resistance to strong polar solvents, such as n-methyl pyrrolidone and dimethyl formamide, that would dissolve other polymers. In fact, Halar fluoropolymers are advertised as incapable of being dissolved by any known solvent up to 300°F. Moreover, the e xtruded, molded, and powder coated surfaces of Halar fluoropolymer exhibit extraordinary smoothness. Despite these favorable attributes, Halar polymers cannot be certified for explosive environments. A series of five sample coatings were developed with graphite being added to the fluoropolymer coating in percentages ranging from about 10%> to about 50%>. The graphite was added to the coating to increase its conductivity and resistance to building up static. The same insulation resistance tests were run on each sample and the results were all well below the 1.0 x 1010 required. In the preferred embodiment, the fluoropolymer coating used on the submergible vehicle has 10%> graphite added to it.
Accordingly, the present invention describes a method and materials for coating components for use in hazardous locations that are capable of meeting Class I Division 1 certification standards that are required for safe use within an explosive environment, as specified in the National Electric Code.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and alterations could be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

Claims of the InventionWhat is claimed is:
1. An anti-static, non-sparking coating comprising: a chemically resistant polymer, said polymer having a high resistivity; and a conductor material , said material having a low resistivity.
2. The coating of Claim 1 wherein said polymer is a fluoropolymer.
3. The coating of Claim 1 wherein said conductor material is carbon powder.
4. An anti-static, non-sparking coating comprising: from about 50%> to about 90%> by weight of a chemically resistant polymer; and from about 10%> to about 50%> by weight of a conductor material.
5. The coating of Claim 4 wherein said polymer is a fluoropolymer.
6. The coating of Claim 4 wherein said conductor material is carbon powder.
7. A method for priming a component to provide chemically resistant and anti-static, non-sparking properties, wherein said component can be used in explosive environments, said method comprising: coating the component with an effective amount of a chemically resistant and anti-static, non-sparking composition; and drying said coating on said component, wherein said coating comprises: from about 50%> to about 90%> by weight of a chemically resistant polymer; and from about 10%> to about 50%o by weight of a conductor material.
8. The method of Claim 7 wherein said polymer is a fluoropolymer.
9. The method of Claim 7 wherein said conductor material is carbon powder.
PCT/US2000/007252 1999-03-18 2000-03-17 Anti-static, non-sparking coatings for explosive environments WO2000054614A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU58659/00A AU5865900A (en) 1999-03-18 2000-03-17 Anti-static, non-sparking coatings for explosive environments

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US12521699P 1999-03-18 1999-03-18
US60/125,216 1999-03-18

Publications (2)

Publication Number Publication Date
WO2000054614A2 true WO2000054614A2 (en) 2000-09-21
WO2000054614A3 WO2000054614A3 (en) 2001-01-11

Family

ID=22418695

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2000/007252 WO2000054614A2 (en) 1999-03-18 2000-03-17 Anti-static, non-sparking coatings for explosive environments

Country Status (2)

Country Link
AU (1) AU5865900A (en)
WO (1) WO2000054614A2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6994305B2 (en) * 2001-04-07 2006-02-07 Robertshaw Controls Company Magnetic mounting assembly
CN105901780A (en) * 2016-05-04 2016-08-31 曾新民 Manufacturing method for uterus warming healthcare briefs containing graphene and used for women

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4902444A (en) * 1988-03-18 1990-02-20 E. I. Dupont De Nemours And Company Conductive fluoropolymers
US5795500A (en) * 1997-03-03 1998-08-18 Xerox Corporation Electrically conductive coatings comprising fluorinated carbon filled fluoroelastomer

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4902444A (en) * 1988-03-18 1990-02-20 E. I. Dupont De Nemours And Company Conductive fluoropolymers
US5795500A (en) * 1997-03-03 1998-08-18 Xerox Corporation Electrically conductive coatings comprising fluorinated carbon filled fluoroelastomer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6994305B2 (en) * 2001-04-07 2006-02-07 Robertshaw Controls Company Magnetic mounting assembly
CN105901780A (en) * 2016-05-04 2016-08-31 曾新民 Manufacturing method for uterus warming healthcare briefs containing graphene and used for women

Also Published As

Publication number Publication date
AU5865900A (en) 2000-10-04
WO2000054614A3 (en) 2001-01-11

Similar Documents

Publication Publication Date Title
Atar et al. Atomic-oxygen-durable and electrically-conductive CNT-POSS-polyimide flexible films for space applications
Pradhan et al. Functional behaviors of electric field grading composite materials
JPS59196509A (en) Flame resistant cable
WO2000054614A2 (en) Anti-static, non-sparking coatings for explosive environments
CN1283772C (en) Precision electronic equipment live cleaning agent
EP0851902B1 (en) Method for coating
CN1246439C (en) Live cleaning agent for high-voltage electric power equipment
CN1295314C (en) Cleaning agent for electrified accurate electronic apparatus
Neufeld et al. Carbon contamination of contacts due to organic vapors
US5976629A (en) Coating compositions
JPS63139944A (en) Electroconductive synthetic resin
Aronstein et al. Overheating failures of aluminum-wired special service connectors
Frankel Effect of vacuum on materials
Derkits et al. Biased mixed flowing gas testing for world class reliability
White Conduction mechanisms in contaminant layers on printed circuit boards
JPH08131949A (en) Polybenzimidazole coating forming method
Antler et al. The effect of environment on electrical contacts: a discussion at the 1973 Holm seminar
Wang et al. Contaminant properties of silicone rubber insulator in the accelerating aging of acid rain
Timmons et al. Photoresist and fluorocarbon postplasma etch residue removal using electrochemically generated radical anions
Indirajith et al. Characterization and Analysis of Intelligent Eco-Friendly Coating for Porcelain Insulator Flash-Over Protection
Campbell et al. Conformal Coating Prevention, Temperature Dependence and Physical Analysis of Resistor Silver Sulfide Corrosion
Sargent et al. Fluorocarbon Gases and Volatile Liquids: Properties and Applications
MacLeod Ross The Uses of Organic Polymers in Electronics Packaging with Particular References to Printed Circuit Modules
Frisco et al. Evaluation of Thin Wall Spacecraft Wiring. Volume 2: Summary and Conclusions.
Meier Non-aqueous cleaning solvent substitution

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): AE AL AM AT AU AZ BA BB BG BR BY CA CH CN CR CU CZ DE DK DM EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): GH GM KE LS MW SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
AK Designated states

Kind code of ref document: A3

Designated state(s): AE AL AM AT AU AZ BA BB BG BR BY CA CH CN CR CU CZ DE DK DM EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A3

Designated state(s): GH GM KE LS MW SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: COMMUNICATION PURSUANT TO RULE 85A(1) EPC COMMUNICATION PURSUNAT TO RULES 85A AND 85B EPC

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS RIGHTS (R. 69(1) EPC)

122 Ep: pct application non-entry in european phase