Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-12-15
2001-11-20
Gallagher, John J. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C106S287130, C428S416000
Reexamination Certificate
active
06319351
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an adhesive bonding process for aluminium and/or aluminium alloy and particularly to a process for improving the durability of a bonded aluminium alloy and/or Alclad (Trade Mark) material joint.
2. Discussion of Prior Art
The durability of adhesive bonded joints for aluminium alloy and/or ALCLAD (Trade Mark) materials is critically dependent on the surface treatment applied to the material surfaces to be joined. Chromic acid anodising and phosphoric acid anodising are two known treatments currently in use with aluminium alloys and which confer good durability properties on the resulting joint. However, in some circumstances such as in repair work, it is not always feasible to apply chromic acid anodising or phosphoric acid anodising treatments and some other durability improving treatment is required which will have a performance approaching that of anodised and primed surfaces as made during initial manufacture.
There is thus a need for a process for improving the durability of a bonded aluminium alloy and/or ALCLAD (Trade Mark) material joint which preferably can be utilised for repair work where chromic acid anodising and phosphoric acid anodising treatments are not feasible or are environmentally toxic.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a process for improving the durability of a bonded aluminium alloy and/or ALCLAD (Trade Mark) material joint, including the steps of:
degreasing surfaces of the material to be joined,
applying to each degreased surface a first solution of from 0.001 to 10% by volume of 1,2-Bis(triethoxysilyl) ethane in water, with or without methanol and/or ethanol, in a range of from 0.01 to 99.9% by volume at a pH value in the range of from 3 to 7,
drying the first solution coated surfaces at a temperature in the range of from 20 to 120° C. for a time in the range of from 1 to 90 minutes,
applying to each dried first solution coated surface a second solution of from 0.01 to 50% by volume of &ggr;-glycidoxypropyltrimethoxysilane, an aminosilane, &ggr;-aminopropyltriethoxysilane, and/or trimethoxyvinylsilane in water, with or without methanol and/or ethanol, in a range of from 0.10 to 99.9% by volume at a pH value in the range of from 3 to 7,
drying the second solution coated surfaces at a temperature in the range of from 20 to 120° C. for a time in the range of from 1 to 120 minutes,
applying a coating of an epoxy adhesive to the dried second solution coated surfaces,
contacting the epoxy adhesive coated surfaces together and
curing the contacted surfaces to bond them together.
Preferably, the aluminium alloy material utilised has a composition containing, by weight 4% copper, up to 1% magnesium, up to 0.3 manganese, balance apart from impurities and incidental constituents, being aluminium,
Conveniently, the degreased surfaces of the material to be joined are roughened before application of the first solution,
Advantageously, the first solution is a 1% by volume aqueous solution or a 1% by volume solution of water and methanol and/or ethanol of 1,2-Bis(triethoxysilyl)ethane and/or 1,2-Bis(triemethoxysilyl)ethane at a pH value in the range of from 3 to 7, hydrolysed for a time in the range of from 10 to 25 hours,
Preferably, the first solution is applied to each degreased surface by brushing, dipping, spraying or wiping and dried at substantially 60° C. for substantially 1 hour,
Conveniently, the second solution is a 1% solution of &ggr;-glycidoxypropyltrimethoxysilane in deionised water at a pH value of substantially 5, hydrolysed for 60 minutes,
Alternatively, the second solution is a 1% solution of &ggr;-glycidoxypropyltrimethoxysilane in deionised water at a pH value of substantially 4, hydrolysed for 10 minutes,
Advantageously, the second solution is applied to each dried first solution coated surface by brushing and dried at substantially 60° C. for substantially one hour,
Preferably, the epoxy adhesive or a hot cured adhesive curable under pressure at a temperature of at least 120° C. for a time in the range of from 1 to 2 hours,
According to a further aspect of the present invention there is provided a bonded aluminium alloy and/or Alclad (Trade Mark) material joint produced by the process of the present invention.
REFERENCES:
patent: 5015506 (1991-05-01), Purcell
patent: 5520768 (1996-05-01), Crook et al.
patent: 98 30735 (1998-07-01), None
BAE Systems plc
Gallagher John J.
Nixon & Vanderhye P.C.
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