Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-04-08
2001-04-24
Gallagher, John J. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C106S287110, C156S326000
Reexamination Certificate
active
06221196
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for improving the adhesion of an elastomeric, polymeric material to a support element while being shaped on and vulcanized, in which the support element is wetted in the region of the adhesion zone with a liquid composition of an adhesion promoter, the coating thus formed is solidified, and the elastomeric material is subsequently shaped on and solidified by vulcanization.
It is known per se to use silanes as adhesion promoters when vulcanizing an elastomeric material onto a support element.
This known procedure does not, however, result in a sufficiently mechanically strong joint between the elastomeric material and the support element with all elastomeric materials. Resins or latices are therefore used for the adhesion of NBR, in order to achieve sufficiently strong adhesion. For practical use in industrial-scale production, this involves considerable complexity.
Thiocyanatosilanes are known per se as additives for use in the manufacture of homogeneous rubber mixtures. Their purpose is to impart better strength to a rubber mixture.
SUMMARY OF THE INVENTION
It is the object of the present invention to describe an adhesion promoter which is simple to use and which guarantees good adhesive strength when sulfur-crosslinked elastomeric materials are utilized.
This and other objects of the invention are achieved by a method for improving the adhesion of an elastomeric, polymeric material to a support element while being shaped on and vulcanized, in which the support element is wetted in the region of the adhesion zone with a liquid composition of an adhesion promoter, the coating thus formed is solidified, and the elastomeric material is subsequently shaped on and solidified by vulcanization, wherein an aqueous and/or alcohol solution of a thiocyanatosilane is used as the adhesion promoter.
DETAILED DESCRIPTION OF THE INVENTION
Thiocyanatosilanes have hitherto not been used at all as adhesion promoters or in the production of adhesion promoters. Surprisingly, they make it possible to achieve extremely good adhesive strength when vulcanizing any sulfur-crosslinked elastomeric material onto a solid object, for example an elastomeric material onto metal. It is important for this purpose to produce an extremely thin and homogeneous film on the support element, which is to the greatest extent possible free of irregularities such as bubbles, variations in film thickness in different areas, and the like. Surprisingly, it is possible with the use of thiocyanatosilanes to meet these requirements without difficulty. It is assumed that the excellent adhesive strength upon subsequent vulcanization of sulfur-crosslinked elastomeric materials is to be attributed to this in particular.
The thiocyanatosilane is advantageously used in dissolved form; the solids content of the solution is to be a maximum of 10 wt % thiocyanatosilane, advantageously less than 5 wt %. In a practical exemplary embodiment which is used in the mass production of shaft sealing rings, the content by weight is 0.8 to 1.0 wt %, advantageously 0.9 wt %. This ensures that what results is a particularly thin and uniform coating of the support elements, for example of the support rings, made of sheet steel, of radial shaft sealing rings. These can have a diameter which begins in the 5-mm category.
The solution can contain a proportion of no more than 50 to 80 wt % alcohol in order to improve film formation homogeneity even further and to prevent irregularities.
Practically any known alcohol can be used as the alcohol, for example methanol, ethanol, propanol, isopropanol, butanols, pentanols, hexanols, and/or mixtures of these various alcohols. The use of ethanol is generally preferred.
The adhesion promoter must be dried gently to ensure that a particularly uniform film is formed. The use of temperatures between 20 and 80° C., advantageously between 40 and 60° C., has proven outstandingly successful.
Particularly good adhesion can be achieved if the adhesion promoter is baked after drying for a period of 5 to 20 minutes at a temperature of 50 to 200° C. Baking is of considerable importance especially for safety-relevant applications, for example for applications in the field of support bearings for machines and devices, and with respect to the adhesion of rubber sealing lips to a sealing ring which is used in shock absorbers, wheel bearings, or in the hydraulic field.
If an aqueous solution is used to constitute the adhesion promoter layer, it has proven to be advantageous if the solution used is acidified. Any acid can, per se, be used. The use of acetic acid has proven particularly advantageous. The strength with which sulfur-crosslinked vulcanisates adhere can be improved if aminosilanes are present in the thiocyanatosilane. The concentration in this context should be no more than 50 wt %; in practical application, it is generally in the range of 0.2 wt %.
The present invention will be explained further below with reference to Examples.
REFERENCES:
patent: 2706166 (1955-04-01), Gurney
patent: 4308071 (1981-12-01), Gervase
patent: 5728203 (1998-03-01), Vorse et al.
patent: 216 944 (1985-01-01), None
patent: 0 603 073 (1994-06-01), None
patent: 0 764 687 (1997-03-01), None
Firma Carl Freudenberg
Gallagher John J.
Kenyon & Kenyon
LandOfFree
Method for improving the adhesion of an elastomeric,... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for improving the adhesion of an elastomeric,..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for improving the adhesion of an elastomeric,... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2456617