GB2314569A - Gasket paper - Google Patents
Gasket paper Download PDFInfo
- Publication number
- GB2314569A GB2314569A GB9613456A GB9613456A GB2314569A GB 2314569 A GB2314569 A GB 2314569A GB 9613456 A GB9613456 A GB 9613456A GB 9613456 A GB9613456 A GB 9613456A GB 2314569 A GB2314569 A GB 2314569A
- Authority
- GB
- United Kingdom
- Prior art keywords
- weight
- silicate mineral
- clay
- silicate
- gasket paper
- 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.)
- Granted
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
- D21H13/10—Organic non-cellulose fibres
- D21H13/20—Organic non-cellulose fibres from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- D21H13/26—Polyamides; Polyimides
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/63—Inorganic compounds
- D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
- D21H17/68—Water-insoluble compounds, e.g. fillers, pigments siliceous, e.g. clays
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Dispersion Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Sealing Material Composition (AREA)
- Paper (AREA)
- Materials For Medical Uses (AREA)
Abstract
A non-asbestos gasket paper comprises, by weight, 4-15% polyaromatic amide fibre pulp, 4-10% polymeric binder, 60-90% silicate mineral and 2-15% inorganic binder. The silicate material may be a layered kaolinitic clay,e.g. calcined china clay, or attapulgite. The polymeric binder may be nitrile rubber. The inorganic binder may be colloidal silica. The paper may be impregnated with a silicone or other resin.
Description
Gasket Paper
This invention relates to papers particularly, but not exclusively, suitable for use in fluid sealing applications such as cylinder head gaskets. It is known to make gasket papers from non-asbestos formulations based on other fibres such as glass fibres and/or mineral fibres and including a minor proportion of cellulose as a web-forming agent. For example. GB-A-2138854 and 2138855 disclose cellulose-containing compositions using ball clay as a filler. GB-A-2250302 discloses a gasket material which is cellulose-free and which includes a carefully selected mixture of calcined china clay and ball clay as filler.
Whilst these non-asbestos products containing ball clay have good performance in non-critical applications, it has been observed that their behaviour at elevated temperatures is not adequate as regards stress relaxation (or creep), particularly when tested over an extended period of time to simulate actual use. Stress relaxation or creep results in a loss of loading in a bolted joint and can lead to gasket failure, so that in temperature critical applications, better stress retention is very desirable.
It has now been discovered that replacement of the ball clay component by a layered kaolinitic clay or a fibrous chain silicate, or by a mixture of these results in improved stress relaxation performance.
According to the present invention, a gasket paper comprises, by
weight, 4-15% aramidfibre pulp, 4-10% polymeric binder, 60-90% silicate mineral and 2-15% inorganic binder. The silicate mineral is preferably a layered kaolinitic clay, or a fibrous chain silicate, or a mixture of these. A particularly preferred clay is a china clay which has been calcined to at least 800"C. A particularly preferred fibrous chain silicate is attapulgite.
According to a further aspect of the invention, at least some of the silicate mineral is constituted by attapulgite.
The inorganic binder is preferably colloidal silica. The polymeric material is preferably nitrile rubber.
A particularly preferred paper according to the invention comprises by weight, 4-8% aramid fibre pulp, 5-8% polymeric binder, 75-90% silicate mineral and 4-10% colloidal silica. It will be appreciated that in the present context "aramid" is a reference to polyaromatic amide material.
The formulations of the present invention may be used in at least two different ways. Firstly, the use of calcined china clay in combination with colloidal silica lends itself to the product of a paper which can be impregnated with a silicone or other resin such as polybutadiene in order to enhance resistance to and sealabilty against fluids such as water-antifreeze mixtures and oil. Alternatively, by including attapulgite it is possible to produce a paper which swells when exposed to water. Such papers can be used without a resin impregnation treatment.
The invention therefore includes a process for producing gaskets from the paper of this invention, both with and without a posttreatment with a resin impregnant.
Surprisingly, it has been found that by eliminating ball clay (previously regarded as a critical ingredient) in favour of the formulations of the present invention, it is possible to achieve improved stress relaxation performance at elevated temperatures, without using inorganic fibres.
In order that the invention be better understood, preferred embodiments of it will now be described by way of example with reference to the following Examples.
In the interests of clarity, the stress relaxation performance was determined by a method based on ASTM test F1276, the samples being exposed to 3000C for 22 hours. It will be appreciated that the latter is significantly longer than some other tests, but investigation reveals that stress relaxation is appreciably higher after longer exposures, which more closely approximate actual use.
Thus testing was carried out by bonding the test paper to both sides of a plain steel core, blanking out annular samples of inside diameter 14.7mm and outside diameter 34.Smm. These were then tested, again based on ASTM F1276, by applying an initial stress of 58.6 MPa. After 22 hours at 3000C the residual stress was measured, the stress relaxation calculated and then normalised to a paper thickness of l.Omm, in the usual way. This procedure was used throughout the following Examples, including tests on paper made according to prior art.
Example 1
A paper was made having the following composition:
% bv dry weight
Fibrillated Aramid Fibre Pulp 8
Calcined China Clay 76
Nitrile Rubber 6
Colloidal Silica 10
Stock Preparation
The aramid fibres were dispersed in water to give a slurry of around 2% solids content by weight. This pulp had a freeness of 500SR. The pulp was transferred to a mixing vessel and further diluted with water at 400C. The calcined china clay was added and the mixture agitated. Further water was added to give a slurry having a solids content of approximately 4% by weight. A 10% solution of papermakers alum was added such that the dry content was approximately 1% of the total composition. The mixture was agitated for 2 minutes before adding the colloidal silica as a 30% solids content suspension. The mixture was agitated for a further 5 minutes and nitrile rubber added in latex form, having a solids content of around 50%. The nitrile rubber latex was diluted 5:1 with water before adding to the mix. When fully dispersed the latex was then caused to precipitate onto the fibres and fillers by the addition of a further quantity of papermakers alum solution until the supernatant liquid became clear.
Paper Manufacture
A paper was produced from the above stock by the conventional technique of dewatering on a wire mesh, pressing and drying, a polyacrylamide flocculant was used to aid processing. The paper was subsequently calendered to the required density using a conventional 2-bowl calender.
The resulting paper had the following properties:
Thickness 0.83mm
Substance 920gum~2 Density llOOkgm3 Tensile Strength 4.2 MPa
Compression at 34.5 MPa 14.3%
Stress Relaxation 24.8%
A conventional paper made according to GB 2250302 showed a stress relaxation of 42% by the same test method.
In additional to the above properties the ability of the paper to seal against a mixture of 50% water and 50% antifreeze (w/w) was measured. A sealing stress of 10.3 MPa was applied to an annular sample of the paper and the internal pressure of the water/antifreeze mixture increased in steps of 1 bar. Each pressure was held for a period of 5 minutes and the pressure at which leakage occurred was noted. Samples of the above paper were found to leak at an internal pressure of 2 bar.
It was found that the sealing performance of the paper could be dramatically improved by impregnation of the paper with a silicone resin, such that a fluid pressure of 10 bar was sealed.
Example 2
A paper was prepared largely as described above from the following formulation.
% bv drv weight
Fibrillated Aramid Fibre Pulp 4
Calcined China Clay 30
Attapulgite 50
Colloidal Silica 10
Nitrile Rubber 6
The paper had the following properties:
Thickness 0.65mm
Substance 860go Density 1330kgm Tensile Strength 7.0 MPa
Compression at 34.5 MPa 15.3%
Stress Relaxation 29.8%
A sealing test was carried out as described above and the paper was found to seal an internal pressure of 10 bar without detectable leakage at a sealing stress of 10.3 MPa. The paper also sealed 10 bar fluid pressure at a reduced sealing stress of 3.4 MPa.
Claims (9)
1. A non-asbestos gasket paper comprising, by weight, 4-1596
aramidLfibre pulp, 4-10% polymeric binder, 60-90% silicate
mineral and 2-15% inorganic binder.
2. A gasket paper according to claim 1 wherein at least some
of the silicate mineral is constituted by a fibrous chain
silicate.
3. A gasket paper according to claim 2 wherein said fibrous
chain silicate is attapulgite.
4. A gasket paper according to any of claims 1-3 wherein the
silicate mineral comprises a layered kaolinitic clay.
5. A gasket paper according to claim 4 wherein the clay
comprises calcined china clay.
6. A gasket paper according to claim 5 wherein said china clay
has been calcined at over 8000C.
7. A gasket paper according to any of claims 1-6 wherein the
inorganic binder is colloidal silica.
8. A gasket paper according to any preceding claim wherein the
polymeric binder is nitrile rubber.
9. A method according to any preceding claim comprising by weight 4
8% aramid fibre pulp, 5-8% polymeric binder, 75-900m silicate mineral,
4-10% inorganic binder.
9. A gasket paper according to any preceding claim comprising
by weight, 4-8% aramid fibre pulp, 5-8% polymeric binder,
75-90% silicate mineral, 4-10% inorganic binder.
10. A gasket paper according to any preceding claim further
comprising a minor proportion (less than 20% by weight) of
inorganic filler.
11. A gasket paper substantially as described with reference to
and as illustrated by Examples 1 and 2.
Amendments to the claims have been filed as follows
CLAIMS 1. A method of manufacture of a paper stock for dewatering to paper,
comprising by weight 4-15% aramid fibre PUlP, 60-90% silicate mineral,
4-10% polymeric binder and 2-15% inorganic binder, comprising the
steps of
mixing the aramid fibres in water to produce a slurry of about 2%
solids content by weight
diluting the pulp with water
adding the silicate mineral to the mixture
agitating the mixture
further diluting the mixture with water to produce a slurry of about 4%
solids content by weight
adding a 10% solution of papermakers alum such that the dry content
is about 1% of the total composition
agitating the mixture
adding to the mixture the inorganic binder
adding to the mixture the polymeric binder having a solids content of
about 50% by weight
waiting until the polymeric binder is fully dispersed and
adding a further quantity of the papermakers alum solution until the
supernatant liquid becomes clear.
2. A method according to claim 1 in which at least some of the silicate
mineral added is constituted by a fibrous chain silicate.
3. A method according to claim 2 in which said added fibrous chain
silicate is attapulgite.
4. A method according to any of claims 1-3 in which the silicate mineral
added comprises a layered kaolinitic clay.
5. A method according to claim 4 wherein the added clay comprises
calcined china day.
6. A method according to claim 5 wherein said added chain clay has
been calcined at over 8000C.
7. A method according to any of claims 16 wherein the inorganic binder
added is colloidal silica.
8. A method according to any preceding claim wherein the polymeric
binder added is nitrile rubber.
Priority Applications (9)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9613456A GB2314569B (en) | 1996-06-27 | 1996-06-27 | Gasket paper |
BR9709944A BR9709944A (en) | 1996-06-27 | 1997-06-12 | Process of making a paper mass to form paper by removing water |
AU30990/97A AU713243B2 (en) | 1996-06-27 | 1997-06-12 | Gasket paper |
DE69704947T DE69704947T2 (en) | 1996-06-27 | 1997-06-12 | SEALING PAPER |
EP97926103A EP0916001B1 (en) | 1996-06-27 | 1997-06-12 | Gasket paper |
KR1019980709356A KR20000015807A (en) | 1996-06-27 | 1997-06-12 | Gasket paper |
JP10502481A JP2000513053A (en) | 1996-06-27 | 1997-06-12 | Gasket paper |
PCT/GB1997/001587 WO1997049864A1 (en) | 1996-06-27 | 1997-06-12 | Gasket paper |
ZA9705620A ZA975620B (en) | 1996-06-27 | 1997-06-25 | Gasket paper. |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9613456A GB2314569B (en) | 1996-06-27 | 1996-06-27 | Gasket paper |
Publications (3)
Publication Number | Publication Date |
---|---|
GB9613456D0 GB9613456D0 (en) | 1996-08-28 |
GB2314569A true GB2314569A (en) | 1998-01-07 |
GB2314569B GB2314569B (en) | 2000-01-26 |
Family
ID=10795958
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9613456A Expired - Fee Related GB2314569B (en) | 1996-06-27 | 1996-06-27 | Gasket paper |
Country Status (9)
Country | Link |
---|---|
EP (1) | EP0916001B1 (en) |
JP (1) | JP2000513053A (en) |
KR (1) | KR20000015807A (en) |
AU (1) | AU713243B2 (en) |
BR (1) | BR9709944A (en) |
DE (1) | DE69704947T2 (en) |
GB (1) | GB2314569B (en) |
WO (1) | WO1997049864A1 (en) |
ZA (1) | ZA975620B (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102011053389A1 (en) * | 2011-09-08 | 2013-03-14 | Elringklinger Ag | Sealing arrangement for use in control plate of automatic transmission, has sealing contour elements made of sealing paper and including height profile with height, which varies between minimum height regions and maximum height regions |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4271228A (en) * | 1980-02-04 | 1981-06-02 | Hollingsworth & Vose Company | Sheet material containing exfoliated vermiculite |
GB2076033A (en) * | 1980-05-07 | 1981-11-25 | Armstrong World Ind Inc | Gasket forming compositions |
GB2138855A (en) * | 1983-04-27 | 1984-10-31 | T & N Materials Res Ltd | Gasket paper |
GB2138854A (en) * | 1983-04-27 | 1984-10-31 | T & N Materials Res Ltd | Gasket paper |
US4786670A (en) * | 1987-01-09 | 1988-11-22 | Lydall, Inc. | Compressible non-asbestos high-temperature sheet material usable for gaskets |
GB2250302A (en) * | 1990-11-29 | 1992-06-03 | T & N Technology Ltd | Gasket paper |
GB2254346A (en) * | 1991-04-02 | 1992-10-07 | T & N Technology Ltd | Non-asbestos gasket material |
WO1992018578A1 (en) * | 1991-04-23 | 1992-10-29 | E.I. Du Pont De Nemours And Company | Industrial gasket for steam application |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA1172414A (en) * | 1981-02-10 | 1984-08-14 | Warren J. Bodendorf | High temperature gasketing material incorporating organic fibers |
DE4122737A1 (en) * | 1991-07-10 | 1993-01-14 | Akzo Nv | COMPOSITION WITH SHORT FIBERS MADE OF ARAMID |
-
1996
- 1996-06-27 GB GB9613456A patent/GB2314569B/en not_active Expired - Fee Related
-
1997
- 1997-06-12 AU AU30990/97A patent/AU713243B2/en not_active Ceased
- 1997-06-12 WO PCT/GB1997/001587 patent/WO1997049864A1/en not_active Application Discontinuation
- 1997-06-12 EP EP97926103A patent/EP0916001B1/en not_active Expired - Lifetime
- 1997-06-12 BR BR9709944A patent/BR9709944A/en unknown
- 1997-06-12 JP JP10502481A patent/JP2000513053A/en active Pending
- 1997-06-12 KR KR1019980709356A patent/KR20000015807A/en not_active Application Discontinuation
- 1997-06-12 DE DE69704947T patent/DE69704947T2/en not_active Expired - Fee Related
- 1997-06-25 ZA ZA9705620A patent/ZA975620B/en unknown
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4271228A (en) * | 1980-02-04 | 1981-06-02 | Hollingsworth & Vose Company | Sheet material containing exfoliated vermiculite |
GB2076033A (en) * | 1980-05-07 | 1981-11-25 | Armstrong World Ind Inc | Gasket forming compositions |
GB2138855A (en) * | 1983-04-27 | 1984-10-31 | T & N Materials Res Ltd | Gasket paper |
GB2138854A (en) * | 1983-04-27 | 1984-10-31 | T & N Materials Res Ltd | Gasket paper |
US4786670A (en) * | 1987-01-09 | 1988-11-22 | Lydall, Inc. | Compressible non-asbestos high-temperature sheet material usable for gaskets |
GB2250302A (en) * | 1990-11-29 | 1992-06-03 | T & N Technology Ltd | Gasket paper |
GB2254346A (en) * | 1991-04-02 | 1992-10-07 | T & N Technology Ltd | Non-asbestos gasket material |
WO1992018578A1 (en) * | 1991-04-23 | 1992-10-29 | E.I. Du Pont De Nemours And Company | Industrial gasket for steam application |
Also Published As
Publication number | Publication date |
---|---|
DE69704947T2 (en) | 2001-09-06 |
AU713243B2 (en) | 1999-11-25 |
EP0916001B1 (en) | 2001-05-23 |
DE69704947D1 (en) | 2001-06-28 |
WO1997049864A1 (en) | 1997-12-31 |
EP0916001A1 (en) | 1999-05-19 |
ZA975620B (en) | 1997-12-29 |
BR9709944A (en) | 1999-08-10 |
GB2314569B (en) | 2000-01-26 |
KR20000015807A (en) | 2000-03-15 |
AU3099097A (en) | 1998-01-14 |
JP2000513053A (en) | 2000-10-03 |
GB9613456D0 (en) | 1996-08-28 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20010627 |