CA1242692A - Dry mix friction bearing material - Google Patents
Dry mix friction bearing materialInfo
- Publication number
- CA1242692A CA1242692A CA000493853A CA493853A CA1242692A CA 1242692 A CA1242692 A CA 1242692A CA 000493853 A CA000493853 A CA 000493853A CA 493853 A CA493853 A CA 493853A CA 1242692 A CA1242692 A CA 1242692A
- Authority
- CA
- Canada
- Prior art keywords
- weight percent
- asbestos
- fiber
- friction material
- friction
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired
Links
Abstract
ABSTRACT
A friction material suitable for use as a bearing, comprising:
(a) 20-40 weight percent phenolic resin;
(b) 5-15 weight percent graphite;
(c) .5-3.5 weight percent carbon black;
(d) 40-60 weight percent of a non-asbestos containing refractory fiber comprising at least 25 wt.% CaO and 35 wt.% SiO2; and (e) 4-10 weight percent acrylic fiber.
A friction material suitable for use as a bearing, comprising:
(a) 20-40 weight percent phenolic resin;
(b) 5-15 weight percent graphite;
(c) .5-3.5 weight percent carbon black;
(d) 40-60 weight percent of a non-asbestos containing refractory fiber comprising at least 25 wt.% CaO and 35 wt.% SiO2; and (e) 4-10 weight percent acrylic fiber.
Description
DRY MIX FRICTION BE~RING MATERIAL
This invention relates to a novel friction product suitable for use as a bearing material.
There exists a continued need in industry for friction products which can be used as bearine materials, especially in the transportation industry. Bearing materials, of course, play an important role in that they help to reduce vibrational movements.
This is quite important in the railroad and automotive industries.
Over the years asbestos has been used as a reinforcing ingredient in friction bearing materials. However, recently asbestos has not been in high demand for use in the industry. Therefore, alternatives for an asbestos containing friction bearing material have been sought which still provide comparable physical properties such as strength, wear rates, good frictional coefficients, etc. as exhibited by the asbestos containing products.
Therefore, it is an object of this invention to provide a non-asbestos containing novel friction product which would make an effective bearing material.
Other aspects, objects, and the several advantages of the present invention will become apparent from this specification and the appended claims.
In accordance with the present invention, I have discovered a novel asbestos free friction material which is useful for bearing applications. This novel material comprises the following ingredients: (a) phenolic resin; (b) graphite; (c) carbon blac~; (d) a non-asbestos containing refractory fiber; and (e) acrylic fiber. .his asbestos-free friction material has physical properties which are comparable to those of asbestos containing friction materials used as bearings.
The following table indicates the general, preferred, and most preferred weight percentage levels for the above ingredients in the novel friction material of the present invention.
,.' ~.!
i ~ I
r~
TA;3LE A
Wei~ht Percent In~redient General Preferred Most Preferred Phenolic Resin20-40 25-35 30 Graphite 5-15 8-12 10 Carbon Black .5-3.5 1-3 2 ~on-Asbestos Refrac- 40-60 45-55 - 51 tory Fiber -~
Acrylic Fiber 4-10 6-8 7 The phenolic resin used in the present invention should be one suitable for use as a binder. Such resins are typically the reaction product of a phenol and an aldehyde of which formaldehyde i5 exemplary. Such materials are quite well known and are widely described in the literature. A typical description will be found in Modern Plastics Encyclopedia, Vol. 4, No. 10(1970-19tl).
~ny commercially available grade of graphite and carbon blacX
can be used in the present invention. Whatever commercially available materials are used, the materials will be essentially pure carbon with particle sizes substantially (i.e. at least about 957v) less than about 74 millimicrons. These materials are incorporated into the friction material for-several reasons including to impart color, to provide strength, and to help impart loh~ friction.
The asbestos-free refractory fibers used in this invention will generally comprise at least 25 wt.% CaO and 35 wt.% SiO2, preferably at least 30 wt.% CaO and 40 wt.% SiO2. Typically the refractory fibers are single-stranded. An exemplary asbestos-free refractory fiber i~- the PMF Fiber produced by Jim Walter Resources, Inc. of Birmingham Alabama. Whatever refractory fiber is employed should generally have an average diameter of 2-10 microns, preferably 4-6 microns, and an average aspect ratio-(length/diameter) of 30-70, preferably 40-60.
For the purposes of this invention, an acrylic fiber is defined as being any fibrous substance containing at least 85 weight percent of acrylonitrile (-CH2CH(CN)-) units. Preferably, the acrylic fiber will be a 100~v polyacrylonitrile homopolymer such as Dolanit 10TM marketed by Hoechst Fiber Industries of Spartanburg, South Carolina.
The materials of this invention may be molded into friction materials in any conventional manner. This normally constitutes pre-mixing of the dry ingredients, insertion of the mixture into a mold and then molding at an elevated temperature and pressure to cause the pnenolic resin binder to form a solid matrix incorporating the other components.
Generally, the temperature for molding the mixture is from about 275F to about 325, with about 300F pre~erred. Typical molding pressures are from about 1000 to about 2000 p.s.i preferably about 1300-1500 p.s.i. The typical molding time is from about lQ
minutes to 50 minutes.
In Table I below, a typical composition of this invention is illustrated. Also illustrated is a typical composition for an asbestos containing friction material. Both compositions were made by the basic mixin~ and molding procedures described herein above.
In Table I, all components are given in percentage by weight (rounded off to the nearest whole percentage). -TABLE I~
Asbestos-Containing Inventive In~redient ComPositionComposition Phenolic Resin (a) ~30% 30~
Amorphous Graphite 10% 10%
Carbon Black 2% 2%
Asbestos Fiber (b) 58% --Refractory Fiber (c) -- ~ 51~
Acrylic Fiber (d) -- - -- 7%
100% 100%
_ -NOTES
(a) Johns-Manville No. 421 Powdered Phenol-Formaldehyde Resin (b) 7D02 Asbestos Fiber (c) Processed Mineral Fiber No. 204 from Jim Walters Resources, Inc., Birmingham, Alabama (d) Dolanit 10 from Hoechst, Spartanburg, N.C.
Table II below gives comparative values for both the asbestos containing and asbestos free compositions af Table I relating to both shear strength and compressive strength.
TABLE II
Asbestos-ContainingInventive PropertY _ Test Method Composition composition_ Shear Strength psiASTM-D-732* 7,050 7,240 Compressive Strength psi ASTM-D-695*
Vltimate > 30,000 ~ 30,000 Yield 18,000 16,650 Modulus of Elasticity121,000 107,100 *0.05 in/min. travel and sample thickness of l/2" nominal.
The above data in Table II indicate that the inventive asbestos-free composition has both shear and compressive strength properties statistically similar to those of the asbestos-containing composition.
Table III below illustrates comparative wear test data for the two compositions of Table I. In such tests, a driven head containing a friction material sample (either asbestos-containing or asbestos-free) of l-5/8" diameter by l/2" thickness is forced against a stationary steel plate under a load of 100 psi. The driven head is rotated at predetermined veloc:ities of from~17 to 68 mph. ~fter an initial run-in period, the actual test is conducted in the following manner: The friction material sample is precisely weighed and measured. It is then put through four "phases" of engagement with the steel plate. In each phase the sample makes a series of engagements with the steel plate, each engagement lasting for a certain interval and is followed by a second cooling and disengagement interval. At the end of each phase the sample is precisely weighed and measured.
Following the four phases, a final "drag" is conducted. In this phase, the sample and steel plate are held in continuous engagement for 30 minutes while the driven head is run at 20 mph.
Results of these tests are shown below:
TABLE III
Rotor Speed Cycle Time No. of v. Co~ff. Frict1on Av. Rate of Wear*
(mDh) (sec.)on/off CYcles A b ComP.~L~T~ L~ L~nV Comp-68 25/75 18 0.13 0.10 0.015 .015 51 15/45 30 0.09 0.08 0.02~ .005 34 10/30 45 0.10 0.11 0.005 003 17 10/30 45 0.14 0.20 0.003 .001 *in3/hp. hr. (1) (2) ~3) (4) (1) 0.115 - Average value
This invention relates to a novel friction product suitable for use as a bearing material.
There exists a continued need in industry for friction products which can be used as bearine materials, especially in the transportation industry. Bearing materials, of course, play an important role in that they help to reduce vibrational movements.
This is quite important in the railroad and automotive industries.
Over the years asbestos has been used as a reinforcing ingredient in friction bearing materials. However, recently asbestos has not been in high demand for use in the industry. Therefore, alternatives for an asbestos containing friction bearing material have been sought which still provide comparable physical properties such as strength, wear rates, good frictional coefficients, etc. as exhibited by the asbestos containing products.
Therefore, it is an object of this invention to provide a non-asbestos containing novel friction product which would make an effective bearing material.
Other aspects, objects, and the several advantages of the present invention will become apparent from this specification and the appended claims.
In accordance with the present invention, I have discovered a novel asbestos free friction material which is useful for bearing applications. This novel material comprises the following ingredients: (a) phenolic resin; (b) graphite; (c) carbon blac~; (d) a non-asbestos containing refractory fiber; and (e) acrylic fiber. .his asbestos-free friction material has physical properties which are comparable to those of asbestos containing friction materials used as bearings.
The following table indicates the general, preferred, and most preferred weight percentage levels for the above ingredients in the novel friction material of the present invention.
,.' ~.!
i ~ I
r~
TA;3LE A
Wei~ht Percent In~redient General Preferred Most Preferred Phenolic Resin20-40 25-35 30 Graphite 5-15 8-12 10 Carbon Black .5-3.5 1-3 2 ~on-Asbestos Refrac- 40-60 45-55 - 51 tory Fiber -~
Acrylic Fiber 4-10 6-8 7 The phenolic resin used in the present invention should be one suitable for use as a binder. Such resins are typically the reaction product of a phenol and an aldehyde of which formaldehyde i5 exemplary. Such materials are quite well known and are widely described in the literature. A typical description will be found in Modern Plastics Encyclopedia, Vol. 4, No. 10(1970-19tl).
~ny commercially available grade of graphite and carbon blacX
can be used in the present invention. Whatever commercially available materials are used, the materials will be essentially pure carbon with particle sizes substantially (i.e. at least about 957v) less than about 74 millimicrons. These materials are incorporated into the friction material for-several reasons including to impart color, to provide strength, and to help impart loh~ friction.
The asbestos-free refractory fibers used in this invention will generally comprise at least 25 wt.% CaO and 35 wt.% SiO2, preferably at least 30 wt.% CaO and 40 wt.% SiO2. Typically the refractory fibers are single-stranded. An exemplary asbestos-free refractory fiber i~- the PMF Fiber produced by Jim Walter Resources, Inc. of Birmingham Alabama. Whatever refractory fiber is employed should generally have an average diameter of 2-10 microns, preferably 4-6 microns, and an average aspect ratio-(length/diameter) of 30-70, preferably 40-60.
For the purposes of this invention, an acrylic fiber is defined as being any fibrous substance containing at least 85 weight percent of acrylonitrile (-CH2CH(CN)-) units. Preferably, the acrylic fiber will be a 100~v polyacrylonitrile homopolymer such as Dolanit 10TM marketed by Hoechst Fiber Industries of Spartanburg, South Carolina.
The materials of this invention may be molded into friction materials in any conventional manner. This normally constitutes pre-mixing of the dry ingredients, insertion of the mixture into a mold and then molding at an elevated temperature and pressure to cause the pnenolic resin binder to form a solid matrix incorporating the other components.
Generally, the temperature for molding the mixture is from about 275F to about 325, with about 300F pre~erred. Typical molding pressures are from about 1000 to about 2000 p.s.i preferably about 1300-1500 p.s.i. The typical molding time is from about lQ
minutes to 50 minutes.
In Table I below, a typical composition of this invention is illustrated. Also illustrated is a typical composition for an asbestos containing friction material. Both compositions were made by the basic mixin~ and molding procedures described herein above.
In Table I, all components are given in percentage by weight (rounded off to the nearest whole percentage). -TABLE I~
Asbestos-Containing Inventive In~redient ComPositionComposition Phenolic Resin (a) ~30% 30~
Amorphous Graphite 10% 10%
Carbon Black 2% 2%
Asbestos Fiber (b) 58% --Refractory Fiber (c) -- ~ 51~
Acrylic Fiber (d) -- - -- 7%
100% 100%
_ -NOTES
(a) Johns-Manville No. 421 Powdered Phenol-Formaldehyde Resin (b) 7D02 Asbestos Fiber (c) Processed Mineral Fiber No. 204 from Jim Walters Resources, Inc., Birmingham, Alabama (d) Dolanit 10 from Hoechst, Spartanburg, N.C.
Table II below gives comparative values for both the asbestos containing and asbestos free compositions af Table I relating to both shear strength and compressive strength.
TABLE II
Asbestos-ContainingInventive PropertY _ Test Method Composition composition_ Shear Strength psiASTM-D-732* 7,050 7,240 Compressive Strength psi ASTM-D-695*
Vltimate > 30,000 ~ 30,000 Yield 18,000 16,650 Modulus of Elasticity121,000 107,100 *0.05 in/min. travel and sample thickness of l/2" nominal.
The above data in Table II indicate that the inventive asbestos-free composition has both shear and compressive strength properties statistically similar to those of the asbestos-containing composition.
Table III below illustrates comparative wear test data for the two compositions of Table I. In such tests, a driven head containing a friction material sample (either asbestos-containing or asbestos-free) of l-5/8" diameter by l/2" thickness is forced against a stationary steel plate under a load of 100 psi. The driven head is rotated at predetermined veloc:ities of from~17 to 68 mph. ~fter an initial run-in period, the actual test is conducted in the following manner: The friction material sample is precisely weighed and measured. It is then put through four "phases" of engagement with the steel plate. In each phase the sample makes a series of engagements with the steel plate, each engagement lasting for a certain interval and is followed by a second cooling and disengagement interval. At the end of each phase the sample is precisely weighed and measured.
Following the four phases, a final "drag" is conducted. In this phase, the sample and steel plate are held in continuous engagement for 30 minutes while the driven head is run at 20 mph.
Results of these tests are shown below:
TABLE III
Rotor Speed Cycle Time No. of v. Co~ff. Frict1on Av. Rate of Wear*
(mDh) (sec.)on/off CYcles A b ComP.~L~T~ L~ L~nV Comp-68 25/75 18 0.13 0.10 0.015 .015 51 15/45 30 0.09 0.08 0.02~ .005 34 10/30 45 0.10 0.11 0.005 003 17 10/30 45 0.14 0.20 0.003 .001 *in3/hp. hr. (1) (2) ~3) (4) (1) 0.115 - Average value
(2) 0.122 - Average value
(3) 0.011 - Average value
(4) 0.006 - Average value The above data in Table III indicates comparable average values (0.115 vs. 0.122) between the asbestos-containing friction composition and the inventive asbestos-free friction composition relating to the average coefficient of friction. However, the test data show a better overall average rate of wear for the inventive composition (0.006 in /hp. hr.) compared to the asbestos-containing composition (0.011 in /hp. hr.).
Reasonable variations and modifications are possible from the foregoing without departin~ from either the scope or spirit of the present invention.
Reasonable variations and modifications are possible from the foregoing without departin~ from either the scope or spirit of the present invention.
Claims (6)
1. A friction material suitable for use as a bearing, comprising:
(a) 20-40 weight percent phenolic resin;
(b) 5-15 weight percent graphite;
(c) .5-3.5 weight percent carbon black;
(d) 40-60 weight percent of a non-asbestos refractory fiber comprising at least 25 wt.% CaO and 35 wt.%
SiO2; and (e) 4-10 weight percent acrylic fiber.
(a) 20-40 weight percent phenolic resin;
(b) 5-15 weight percent graphite;
(c) .5-3.5 weight percent carbon black;
(d) 40-60 weight percent of a non-asbestos refractory fiber comprising at least 25 wt.% CaO and 35 wt.%
SiO2; and (e) 4-10 weight percent acrylic fiber.
2. A friction material, according to Claim 1 suitable for use as a bearing, comprising:
(a) 25-35 weight percent phenolic resin;
(b) 8-12 weight percent graphite;
(c) 1-3 weight percent carbon black;
(d) 45-55 weight percent of a non-asbestos refractory fiber comprising at least 25 wt.% CaO and 35 wt.%
siO2; and (e) 6-8 weight percent acrylic fiber.
(a) 25-35 weight percent phenolic resin;
(b) 8-12 weight percent graphite;
(c) 1-3 weight percent carbon black;
(d) 45-55 weight percent of a non-asbestos refractory fiber comprising at least 25 wt.% CaO and 35 wt.%
siO2; and (e) 6-8 weight percent acrylic fiber.
3. A friction material, according to Claim 2, comprisisng:
(a) 30 weight percent phenolic resin;
(b) 10 weight percent graphite;
(c) 2 weight percent carbon black;
(d) 51 weight percent of a non-asbestos refractory fiber comprising at least 25 wt.% CaO and 35 wt.%
SiO2; and (e) 7 weight percent acrylic fiber.
(a) 30 weight percent phenolic resin;
(b) 10 weight percent graphite;
(c) 2 weight percent carbon black;
(d) 51 weight percent of a non-asbestos refractory fiber comprising at least 25 wt.% CaO and 35 wt.%
SiO2; and (e) 7 weight percent acrylic fiber.
4. A friction material according to Claim 1 wherein said phenolic resin in 1(a) is a phenol-formaldehyde resin.
5. A friction material according to Claim 1 wherein said non-asbestos refractory fiber in 1(d) comprises at least 30 wt.% CaO and 40 wt.% SiO2.
6. A friction material according to Claim 1 wherein said acrylic resin is a 100% acrylonitrile homopolymer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000493853A CA1242692A (en) | 1985-10-25 | 1985-10-25 | Dry mix friction bearing material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000493853A CA1242692A (en) | 1985-10-25 | 1985-10-25 | Dry mix friction bearing material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1242692A true CA1242692A (en) | 1988-10-04 |
Family
ID=4131710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000493853A Expired CA1242692A (en) | 1985-10-25 | 1985-10-25 | Dry mix friction bearing material |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1242692A (en) |
-
1985
- 1985-10-25 CA CA000493853A patent/CA1242692A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |