Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-12-21
2002-07-30
Chang, Rick K. (Department: 3729)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S179000, C156S181000, C156S273500, C156S274600, C156S275500, C156S437000, C264S175000, C029S728000, C029S820000, C029SDIG003, C029S527200
Reexamination Certificate
active
06425970
ABSTRACT:
TECHNICAL FIELD
The invention relates to apparatus and a method of processing elastomeric materials. In particular, the process is directed to a means of producing carbon carbon bonds in a vulcanizable elastomer, and in particular, an elastomer that contains wire reinforcement.
BACKGROUND OF THE INVENTION
Electron beam processing (EBP) is known in the art for treating elastomeric materials to enhance their green strength. EBP activates carbon atoms in a polymer and induces carbon carbon crosslinking. Carbon carbon cross linking in a green elastomer gives the elastomer added strength that makes it possible in some cases, and easier in other cases, to handle the green elastomer during processing before vulcanization.
Electron beam processing is known to induce an electromotive force in wire cords, along with a potentially high voltage, and for such reasons electron beam processing of wire reinforced elastomers has been generally avoided in the past.
In prior attempts to provide a means for using EBP on wire reinforced elastomers, a shunt was connected across the wire cords at the beginning of each windup roll. The shunt was then connected to plant ground potential at the windup.
On all fabric and wire calender lines, static build-up was removed with wire brushes, which require frequent replacement because of fast wear and lost contact with the sheet product.
Previous experiments have shown that the electric potential in a wire-reinforced elastomer that is subjected to EBP can be as high as 2,500 volts, with a very small current (in the milliamp (MA) range). This induced potential can damage an elastomer by arcing from wire to wire in the elastomer, thereby burning the rubber and also causing a safety hazard to the machine operator.
It is an object of this invention to provide an apparatus and method, which makes it possible to treat a wire, reinforced elastomer with electron beam processing.
It has been found, using the method of this invention, that static build-up that normally occurs when calendering elastomeric products can also be substantially eliminated.
Other objects of the invention will be apparent from the following description and claims.
SUMMARY OF INVENTION
A method of forming a reinforced composite
17
on a calender
11
comprises the steps of a) grounding guide rolls
19
that contact reinforcement
12
from a creel
18
prior to feeding the reinforcement
12
to a calender
11
, b) coating the reinforcement
12
with rubber
23
while on the calender
11
to form a reinforced composite
17
, and c) grounding rolls which contact the reinforced composite as the composite exits the calender
11
.
The method in steps (a) and (c) may further comprise the steps of I) attaching slip rings
36
to rolls
14
,
15
,
19
,
21
which contact the reinforcement
12
and the composite
17
on the calender
11
, and II) connecting the slip rings
36
to ground
27
.
The method in step (a), comprising grounding reinforcement
12
from a creel
18
, may further comprise the further steps of I) drilling and tapping the end of a roller shaft
32
a
to provide a threaded hole
37
for receipt of a bolt
39
, II) threading a first end of bolt
39
into the threaded hole
37
, III) attaching a slip ring
36
to a second end of the bolt
39
, whereby the slip ring
36
rotates with the roll
32
, IV) connecting a second bolt
38
to bearings within the slip ring
36
and attaching an electrical terminal
34
to the second bolt
38
whereby the terminal
34
remains stationary, and V) connecting the terminal
34
to ground
27
.
In one embodiment, the method may comprise the further step of subjecting the reinforced composite to electron beam processing (EBP).
In further refinements of the method, the method may include the further step of placing at least one roll above the plane of the reinforced composite and at least one roll below the plane of the reinforced composite. Also, a further step of connecting bare wires to ground during calender changeover may be used.
In the illustrated embodiment, the method includes the step of subjecting a calendered sheet comprising rubber-coated wire to an electron beam of 2 to 14 mega-RADs.
In the illustrated embodiment, the slip ring
36
is provided as a mercury wetted slip ring.
Also provided is an apparatus
10
for grounding materials on a calender
11
which is used to coat wire reinforcement
12
with rubber
23
, wherein the apparatus
10
comprises, a) at least one roll
14
,
15
,
19
,
21
for transporting material through a calender, b) at least one slip ring
36
connected to the roll whereby the slip ring
36
rotates with the roll while a terminal
34
attached to the slip ring stays substantially stationary while the roll rotates, and c) an electrical conductor
26
connecting each of the at least one slip ring
36
to ground
27
. The apparatus
10
may further comprise d) an organizer roll
15
for directing wire through the calender
11
, the roll having a first end of a conductive rod attached at one end thereof, and e) a slip ring
36
attached to a second end of the conductive rod
39
.
In an illustrated embodiment, at least one roll is an organizer roll
15
, and the conductive rod is a bolt
39
having a first end threaded into a threaded hole
37
in an end of the organizer roll. Also, a terminal
34
is connected to bolt
38
which is connected to bearings in slip ring
36
.
The calender
11
includes apparatus
16
for applying a rubber coat on material passing through the calender
11
. The apparatus
10
may include at least one grounding point on the calendered sheet
17
downstream of the calender
11
, the at least one grounding point optimally comprising a guide roll
21
for the calendered sheet.
In the preferred embodiment, the apparatus further comprises an electron beam source
28
associated with the calender
11
down stream of a rubber coating apparatus
16
on the calender
11
.
REFERENCES:
patent: 3926132 (1975-12-01), Lear et al.
patent: 5000807 (1991-03-01), Stuart
patent: 5190774 (1993-03-01), Koichi et al.
patent: 6295931 (2001-10-01), Cutler et al.
Koch Brian Richard
Ripple Warren Paul
Chang Rick K.
Wheeler David E
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