US3711428A - Electrical resistor paste containing a small amount of charcoal - Google Patents

Electrical resistor paste containing a small amount of charcoal Download PDF

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Publication number
US3711428A
US3711428A US00111295A US3711428DA US3711428A US 3711428 A US3711428 A US 3711428A US 00111295 A US00111295 A US 00111295A US 3711428D A US3711428D A US 3711428DA US 3711428 A US3711428 A US 3711428A
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United States
Prior art keywords
paste
charcoal
resistor
vehicle
percent
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Expired - Lifetime
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US00111295A
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English (en)
Inventor
T Aycock
J Wright
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International Business Machines Corp
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International Business Machines Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/003—Thick film resistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/14—Conductive material dispersed in non-conductive inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
    • H01C17/06—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base
    • H01C17/065—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base by thick film techniques, e.g. serigraphy
    • H01C17/06506—Precursor compositions therefor, e.g. pastes, inks, glass frits or green body
    • H01C17/06573—Precursor compositions therefor, e.g. pastes, inks, glass frits or green body characterised by the permanent binder
    • H01C17/0658—Precursor compositions therefor, e.g. pastes, inks, glass frits or green body characterised by the permanent binder composed of inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
    • H01C17/06—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base
    • H01C17/065—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base by thick film techniques, e.g. serigraphy
    • H01C17/06506—Precursor compositions therefor, e.g. pastes, inks, glass frits or green body
    • H01C17/06573—Precursor compositions therefor, e.g. pastes, inks, glass frits or green body characterised by the permanent binder
    • H01C17/06586—Precursor compositions therefor, e.g. pastes, inks, glass frits or green body characterised by the permanent binder composed of organic material

Definitions

  • a resistor paste composition contains a small amount of powdered activated charcoal. The composition is applied to a ceramic substrate by screen printing, fired at an elevated temperature, and cooled to room temperature to form an electricalre sistor element' 7 Claims, 5 Drawing Figures PATENTEDJAH 16 1975 FIG. 1
  • FIG. 1 A first figure.
  • FIG. 5 THOMAS w. AYCOCK JOHN J. WRIGHT A TTORNEY SMALL AMOUNT OF CHARCOAL BACKGROUND OF THE INVENTION printed wiring.
  • the functional components are active and passive electric circuit elements capable of performing useful functions or operations. Passive devices such as resistors are normally applied to the substrate by printing techniques.
  • the resistor compositions consist of a mixture of powdered insulating materials such as glass and powdered conductive materials such as metals and metal oxides, which may contain dopants to increase or decrease resistivity.
  • the resistor compositions are applied to the module surface in the form of a paste by dispersing the powdered materials in a vehicle comprising a volatile solvent, resin, and wetting agent. The compositions are then fired at elevated temperatures. The firing dries off or burns out the vehicle to leave the fused insulating and conductive materials forming the resistor element.
  • resistors With known resistor compositions it has not been found practical to initially print the resistors to the proper dimensions to achieve the desired resistance values.
  • General practice therefore, is to print and fire a resistor that is slightly oversized. The resistor is then trimmed, such as by a sand blasting process, to abrad away a portion of the resistor until the correct resistance value is obtained.
  • Such resistor elements, compositions, and methods are described for example in U.S. Pat. Nos. 3,248,345; 3,345,158; 3,374,110; 3,390,l04;3,401,l26;3,4l l,947;and 3,414,641.
  • the craters adversely effect the electrical properties of the resistor element.
  • the blistering which results in weak spots in the resistor element, are a problem during the trimming process.
  • a relatively large blistered section of resistor may break away. This results in a sudden change in resistance value which may place the resistor outside of the set tolerance limits. Usually when this occurs the entire module must be discarded as unusable.
  • the encapsulating material may cause a weakened or blistered portion of the resistor to separate from the module and the main body of the resistor element. This may place the resistance value beyond the acceptable tolerances and a completed module containing all of the elements in- I cluding the semiconductor chips must be discarded.
  • a resistor paste composition comprises a mixture of a powdered conductive material, a powdered insulating material, an effective amount of powdered activated charcoal, and a vehicle comprising a volatile solvent and a resin binder.
  • the resistor is formed by depositing the paste composition on the surface of a substrate and solidifying it by firing it at an elevated temperature to drive off the charcoal and the vehicle.
  • the resistor element prepared by the above process has a relatively smooth surface texture with a minimum of blisters and craters.
  • FIG. 1 is a microphotograph of a resistor element made in accordance with a process of the invention.
  • FIG. 2 is a cross section of the resistor element of FIG. 1 taken along lines 22.
  • FIG. 3 is a microphotograph of a resistor element prepared without charcoal.
  • FIG. 4 is a cross sectional view of the resistor element of FIG. 3 taken along lines 4-4.
  • FIG. 5 shows the element of FIG. 4 after a trimming operation.
  • the resistor paste is made up of a conductive solids mixture and an inert liquid vehicle.
  • the solids mixture comprises about 50 to 83 percent by weight combined with 17 to 50 percent by weight of vehicle.
  • the conductive solids mixture or pigment is conventional and comprises, for example, a metal and/or oxide, a glass frit, and dopant ions.
  • Metals and metal oxides include, for example, silver, indium, antimony, chromium, palladium, copper and mixtures thereof.
  • the pigment will contain from about 30 to 50 percent by weight of the finely divided conductive material and 50 to percent by weight of the finely divided glass frit.
  • the component materials have a particle size preferably in the range of l to 50 microns. Such pigment mixtures are well known in the art.
  • Included in the paste mixture is an amount of finely divided highly activated wood charcoal sufficient to substantially reduce the formation of craters and/or blisters in the fired resistor elements.
  • Preferred amounts of charcoal range from about 0.4 percent to about 2 percent by weight of the total weight of paste. The range is not particularly critical but the amount of charcoal should be chosen to obtain a significant amount of blister and crater elimination without being excessive so as to adversely effect the flow properties of the paste (above about 0.2 percent but less than about 4.0 percent by weight based on the total weight of paste).
  • the charcoal preferably has a particule size such that substantially all of it will pass through a 325 mesh U.S. standard screen.
  • Suitable charcoals are highly purified or activated charcoals having a large surface area such as are used, for example, in packing gas purification columns or pharmaceutical grade highly refined wood charcoal.
  • the vehicles are conventional and usually comprise a non polar solvent combined with a resin, and sometimes a wetting agent.
  • the resin in combination with the solvent gives the resistor composition the desired flow characteristics.
  • the composition-must be fluid enough to allow the employment of silk screening techniques but sufficiently firm after being printed or transferred to the substrate to maintain its physical dimensions prior to drying.
  • the wetting agents are employed to aid in dispersing and maintaining the solid pigment materials in suspension in the vehicle. The wetting agents also aid in the screening characteristics.
  • the vehicles constitute '17 to 50 percent by weight and more preferably 20 to 30 percent by weight of the total weight of resistor paste composition.
  • the resin components are conventional and include for example natural gums, cellulosic materials and synthetic resins.
  • Suitable volatile solvents are those having a relatively low vapor pressure at room temperature and a relatively high vapor pressure at elevated temperatures.
  • Solvents which are commonly employed are higher boiling paraffins, cycloparaffins, terpineol and aromatic hydrocarbons such as ethyl naphthalene, phenylcyclohexane, and mixtures thereof; or one or more of the mono and di-alkyl ethers of diethylene glycol or their derivatives such as diethylene glycol monobutyl ether acetate.
  • Surfactants or dispersing agents suitable for use are, for example, organic derivatives such as polyoxyethylene alcohol non-ionic surfactants, alkylaryl sulfonate's, and fatty acid esters.
  • the resin generally comprises from about 20 to 80 percent by weight of the total weight of the vehicle and the volatile liquid from about 80 to 20 percent by weight of the total weight of the vehicle.
  • the solvent preferably constitutes 50 to 70 percent byweight of the total weight of the vehicle.
  • preparing the resistor paste conventional mixing procedures are employed. Usually the conductive solids mixture is thoroughly mixed by any suitable conventional dry mixing procedure such as, for example, by shaking in a closed container using a paint mixer. The vehicle and pigment mixture are then thoroughly mixed. A mixing procedure using a three roll mill such as is described, for example, in U.S. Pat. No. 3,414,641 7 can be employed.
  • the charcoal can be added either to the dry conductive mixture prior to blending with the vehicle or it can be added to the resistor paste mixture.
  • Resistor elements are formed by depositing the paste onto the substrate using conventional techniques, for example, by screening, drying the paste in a furnace at temperatures of from about 100 to 300 C. and then firing the paste at elevated temperatures up to about 760 C. to driveoff the vehicle and fuse the conductive and insulating powders. It has been found that the firing process also removes substantially all of the charcoal so that the resistance properties are not affected by the presence of any residual charcoal. The presence of the charcoal during the firing process produces a relatively smooth, crater and void free resistor element which has excellent electrical properties and which will adhere to the substrate during trimming operations and during use.
  • the powders were mixed for 15 minutes in a closed container on a paint shaker.
  • a vehicle for the resistor paste was made up of the following constituents:
  • EXAMPLE 2 A resistor element was prepared according to the formulary and method of Example 1 except that no charcoal was added to the dry mix. After firing, the surface of the resistor element had a cratered and blistered appearance.
  • FIGS. 1 through 4 illustrate typical resistor elements prepared by the processes of Examples 1 and 2.
  • the resistor element 11, formed by the composition and process of the invention on the surface of substrate 13 betweenconductor lines 15, has a relatively smooth surface with little if any blistering or cratering being observable (FIGS. 1 and 2).
  • resistor element 11 has a solid cross section.
  • the resistor element 21 on substrate 23 between conductive elements 25 prepared in accordance with Example 2 has a rough uneven surface appearance with craters and blistering being visually apparent. This is further illustrated in FIG.
  • the fired resistor elements were analyzed for residual carbon content with a somewhat higher percent carbon (0.25 vs. less than 0.0l per cent average of two determinations) found in the element prepared from the paste with the activated charcoal.
  • the electrical properties of the resistor element of Examples 1 and 2 are illustrated in Table 1 below:
  • the novel resistor element is not adversely affected by any residue resulting from the presence of the activated charcoal during the resistor preparation.
  • EXAMPLE 3 A resistor element was prepared using the formula and procedure of Example 1 except that a different vehicle was employed.
  • the vehicle was made up of the following constituents:
  • the resistor element prepared from the resistor paste by the procedure followed in Example 1 had excellent electrical properties and a relatively smooth surface contour which had few if any craters or voids and a substantially solid cross section.
  • resistor pastes were formulated using the dry conductor mixture and vehicle as prepared in Example 1 except that the paste was first mixed without the charcoal additive and to three portions of the mixed paste were added varying amounts as shown in Table 2 below of a pharmaceutical grade of activated charcoal which was ground to pass through a 325 mesh screen (U.S. standard sieve series). After the addition of the charcoal to each portion of paste, the paste was milled six more times through the three roll mill. Resistor elements were prepared in accordance with the procedure of Example 1. The amount of blistering was visually TABLE 2 Charcoal (by wt.
  • a resistor paste containing about 50 to 83 percent by weight of paste ofa solid portion, said solid portion comprising about 30 to 50 percent by weight of the solid portion of a powdered conductive material selected from the group consisting of metals, metal oxides and mixtures thereof and about 50 to 70 percent by weight of solid portion of a about 17 to 50 percent by weight of paste of a vehicle, said vehicle comprising about 20 to percent by weight of vehicle of an organic polymer and about 20 to 80 percent by weight of vehicle of a volatile non-polar solvent,
  • the improvement which comprises including in said paste, from about 0.2 to 4.0 percent by weight of the total weight of paste, of an activated charcoal having a particle size such that it will pass through a 325 mesh U.S. standard screen.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Dispersion Chemistry (AREA)
  • Non-Adjustable Resistors (AREA)
  • Conductive Materials (AREA)
  • Adjustable Resistors (AREA)
US00111295A 1971-02-01 1971-02-01 Electrical resistor paste containing a small amount of charcoal Expired - Lifetime US3711428A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US11129571A 1971-02-01 1971-02-01

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US (1) US3711428A (2)
JP (1) JPS5219316B1 (2)
DE (1) DE2202395C2 (2)
FR (1) FR2124232B1 (2)
GB (1) GB1317669A (2)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3964924A (en) * 1975-07-11 1976-06-22 Pfizer Inc. Protective coating for graphite electrodes
US3992212A (en) * 1972-08-18 1976-11-16 Universal Oil Products Company Electrical resistor inks
US4079156A (en) * 1975-03-07 1978-03-14 Uop Inc. Conductive metal pigments
DE2814770A1 (de) * 1978-04-05 1979-10-11 Uop Inc Verfahren zur herstellung von leitfaehigen metallpigmenten
DE3317912A1 (de) * 1982-05-17 1983-11-17 UOP Inc., 60016 Des Plaines, Ill. Verfahren zur herstellung einer leitfaehigen pigmentbeschichteten oberflaeche
US4547310A (en) * 1983-03-30 1985-10-15 Murata Manufacturing Co., Ltd. Carbon resistive paste
US4786524A (en) * 1987-07-08 1988-11-22 The United States Of America As Represented By The United States Department Of Energy Coating formulation and method for refinishing the surface of surface-damaged graphite articles
US4937493A (en) * 1987-12-28 1990-06-26 Kabushiki Kaisha Toshiba Cathode ray tube with an electrical connecting element
US5696198A (en) * 1996-01-22 1997-12-09 Electrosorbent, Inc. Porous electroconductive composite material, and method of manufacturing the same
US6534582B1 (en) * 1998-10-12 2003-03-18 Alcatel Adaptive material of ternary composition
US6551527B2 (en) 2000-08-29 2003-04-22 Shoei Chemical Inc. Conductive paste comprising N-acylamino acid
US20060021465A1 (en) * 2004-07-30 2006-02-02 Jfe Mineral Company, Ltd. Ultrafine metal powder slurry
US20100033295A1 (en) * 2008-08-05 2010-02-11 Therm-O-Disc, Incorporated High temperature thermal cutoff device
US9171654B2 (en) 2012-06-15 2015-10-27 Therm-O-Disc, Incorporated High thermal stability pellet compositions for thermal cutoff devices and methods for making and use thereof

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6219273U (2) * 1985-07-18 1987-02-05

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US241529A (en) * 1881-05-17 Manufacture of sheet-iron
US1747649A (en) * 1929-01-05 1930-02-18 Ruben Patents Company Method of making a resistance element
US3010842A (en) * 1955-08-29 1961-11-28 Xerox Corp Development of electrostatic images
US3248345A (en) * 1963-10-01 1966-04-26 Ibm Electrical resistance compositions, elements and methods of making same
US3293183A (en) * 1961-08-14 1966-12-20 Australia Res Lab Developer for electrostatic images
US3390104A (en) * 1965-07-16 1968-06-25 Ibm Electrical resistor compositions, elements and method of making same
US3410714A (en) * 1965-10-18 1968-11-12 Gen Electric Metallizing and bonding non-metallic bodies
US3411947A (en) * 1964-06-29 1968-11-19 Ibm Indium oxide resistor composition, method, and article

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3342752A (en) * 1965-09-02 1967-09-19 Matsushita Electric Industrial Co Ltd Carbon film resistor composition
US3538021A (en) * 1968-05-07 1970-11-03 Gen Motors Corp Resistor composition

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US241529A (en) * 1881-05-17 Manufacture of sheet-iron
US1747649A (en) * 1929-01-05 1930-02-18 Ruben Patents Company Method of making a resistance element
US3010842A (en) * 1955-08-29 1961-11-28 Xerox Corp Development of electrostatic images
US3293183A (en) * 1961-08-14 1966-12-20 Australia Res Lab Developer for electrostatic images
US3248345A (en) * 1963-10-01 1966-04-26 Ibm Electrical resistance compositions, elements and methods of making same
US3411947A (en) * 1964-06-29 1968-11-19 Ibm Indium oxide resistor composition, method, and article
US3390104A (en) * 1965-07-16 1968-06-25 Ibm Electrical resistor compositions, elements and method of making same
US3410714A (en) * 1965-10-18 1968-11-12 Gen Electric Metallizing and bonding non-metallic bodies

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3992212A (en) * 1972-08-18 1976-11-16 Universal Oil Products Company Electrical resistor inks
US4079156A (en) * 1975-03-07 1978-03-14 Uop Inc. Conductive metal pigments
US3964924A (en) * 1975-07-11 1976-06-22 Pfizer Inc. Protective coating for graphite electrodes
DE2814770A1 (de) * 1978-04-05 1979-10-11 Uop Inc Verfahren zur herstellung von leitfaehigen metallpigmenten
DE3317912A1 (de) * 1982-05-17 1983-11-17 UOP Inc., 60016 Des Plaines, Ill. Verfahren zur herstellung einer leitfaehigen pigmentbeschichteten oberflaeche
US4547310A (en) * 1983-03-30 1985-10-15 Murata Manufacturing Co., Ltd. Carbon resistive paste
US4786524A (en) * 1987-07-08 1988-11-22 The United States Of America As Represented By The United States Department Of Energy Coating formulation and method for refinishing the surface of surface-damaged graphite articles
US4937493A (en) * 1987-12-28 1990-06-26 Kabushiki Kaisha Toshiba Cathode ray tube with an electrical connecting element
US5696198A (en) * 1996-01-22 1997-12-09 Electrosorbent, Inc. Porous electroconductive composite material, and method of manufacturing the same
WO1999023671A1 (en) * 1996-01-22 1999-05-14 Electrosorbent Inc. Porous electroconductive composite material
US6534582B1 (en) * 1998-10-12 2003-03-18 Alcatel Adaptive material of ternary composition
US6551527B2 (en) 2000-08-29 2003-04-22 Shoei Chemical Inc. Conductive paste comprising N-acylamino acid
US20060021465A1 (en) * 2004-07-30 2006-02-02 Jfe Mineral Company, Ltd. Ultrafine metal powder slurry
US20080237548A1 (en) * 2004-07-30 2008-10-02 Jfe Mineral Company, Ltd. Ultrafine metal powder slurry
US7442226B2 (en) * 2004-07-30 2008-10-28 Jfe Mineral Company, Ltd. Ultrafine metal powder slurry
US7601197B2 (en) 2004-07-30 2009-10-13 Jfe Mineral Company, Ltd. Ultrafine metal powder slurry
US20100033295A1 (en) * 2008-08-05 2010-02-11 Therm-O-Disc, Incorporated High temperature thermal cutoff device
US8961832B2 (en) 2008-08-05 2015-02-24 Therm-O-Disc, Incorporated High temperature material compositions for high temperature thermal cutoff devices
US9779901B2 (en) 2008-08-05 2017-10-03 Therm-O-Disc, Incorporated High temperature material compositions for high temperature thermal cutoff devices
US9171654B2 (en) 2012-06-15 2015-10-27 Therm-O-Disc, Incorporated High thermal stability pellet compositions for thermal cutoff devices and methods for making and use thereof

Also Published As

Publication number Publication date
DE2202395C2 (de) 1983-01-05
FR2124232B1 (2) 1974-06-21
JPS5219316B1 (2) 1977-05-27
DE2202395A1 (de) 1972-08-24
FR2124232A1 (2) 1972-09-22
GB1317669A (en) 1973-05-23

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