P awling Custom Rubber and Plastic Products

www.pawling.com/custom
Pawling Custom Rubber and Plastic Products
Table of Contents
Market Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-7
Profile Constructs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Secondary Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Available Materials
Thermoplastic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Thermoset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Tolerance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Standard Profiles and Stock Items . . . . . . . . . . . . . . .14-16
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Market Solutions
Pawling Engineered Products specializes in the custom design
and manufacture of seals, gaskets, and other engineered rubber
products. Advanced compounding, molding, extruding, and
fabricating coupled with testing equipment and other techniques
enable us to address your most demanding needs for highly
durable and reliable rubber fabrications.
VAB Double Bulb Door Seal
Market:
Aerospace/Construction
Material:
EPDM
Detail: A large EPDM double bulb extrusion is used to
seal the edges of the Vertical Assembly Building (VAB)
Doors at the Kennedy Space Center in Cape Canaveral,
Florida. This design allows for horizontal movement
between the bulbs while the door is operational and
provides dual sealing surfaces to keep the weather out.
This part is extruded using our largest extruder and
spliced in the field by our technical staff.
Multi-Laminate Silicone
Wing Flap Seal
Market:
Aerospace/Defense
Material:
Silicone, Fabric, and Polyester
Detail: This part requires three unique materials to be
compression molded into one compete gasket. The fabric outer layer is used to reduce the part’s co-efficient
of friction and to increase useful life. Silicone is used to
handle temperature extremes and the rigid polyester
base is used to prevent seal pullout from its housing.
This seal is manufactured utilizing special molds and
long presses to conform to the tight tolerances required
for this application.
4
Pawling Custom Rubber and Plastic Products
Low Outgassing
Expansion Joint
Market:
Cleanrooms/Laboratories
Material:
Silicone
Detail: Ductwork enclosing a conveyor belt connects
several clean rooms together, allowing for material
movement between rooms. To address outgassing
concerns and to account for slight movement in the
ducting, Pawling designed a molded expansion joint
made from a low outgassing silicone material (70643).
Manufacture of this molded gasket is tightly controlled
as any contaminants could compromise the clean
room environment.
One-Piece Zipper Gasket
Market:
Transportation/ Construction
Material:
Flexible PVC
Detail: This zipper design replaces a traditional twopiece sealing system where a smaller gasket would be
installed into the mating channel of a larger gasket.
During installation, the gasket is placed onto the
aluminum frame. The glass is then inserted into the
inside channel and the zipper is pushed into place. This
action locks the gasket and window together, which
improves the part’s effectiveness and ultimately lowers
overall unit cost.
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5
Market Solutions
Roof Window Gasket
Market:
Construction
Material:
EPDM
Detail: A unique, multi-faceted profile is spliced into a
picture frame which serves as a seal between the roof
window housing and frame. This part is manufactured
using a high quality EPDM (E787M) with multiple
sealing points, which reduces potential leakage.
Using a dedicated work cell, Pawling manufactures
these gaskets on demand through use of a unique
molding and extruding process.
Chemical Processing Seal
Market:
Electronics/Semi-Conductor Processing
Material:
Fluorosilicone
Detail: Fluorosilicone is used to combat both high
temperatures and aggressive chemicals. In this
application, semi-conductor assemblies are treated in
a large chemical bath. The fluorosilocone P-strip is
used to seal the cover while the machine is operational.
6
Pawling Custom Rubber and Plastic Products
Fabric Reinforced Valve Seat
Market:
Power Plant/Construction
Material:
Natural Rubber
Detail: Using our unique long press capabilities, Pawling
manufactures an 8” (203 mm) wide, fully molded fabric
reinforced expansion joint in long continuous lengths
used for large pipe assemblies in power plants.
Diameters approaching 8-10 feet (2438-3048 mm) are
not uncommon. Depending on the requirements, this
part can either be molded and spliced endless or can be
step-cured into a complete gasket.
Magnetic Sterilizer Gasket
Market:
Medical/Sterilizers
Material:
Silicone
Detail: This sterilizer gasket withstands the rigors of
high temperatures and latches the door by using
magnets which are installed within the seal. This dual
system combines the seal and latch into one unit,
which simplifies design. Silicone is used to ensure the
gasket maintains its effectiveness even under high
temperatures.
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7
Profile Constructs
Dense - The majority of our parts are manufactured using dense materials. Dense profiles are
resilient and extrudable whereas some other
constructs can only be molded.
Co-Extruded - Some applications require two
types of material (usually having different durometers) to be joined together to form one part. A typical application involves a rigid component that acts
as a retainer and a flexible component to act as a
seal or bumper.
Sponge - Sponge extrusions provide a soft, supple
seal while optimizing material usage. Sponge
profiles should not be used where compression set
is important, because the part will eventually take
a permanent set.
Fabric Reinforced - Fabric reinforcement serves
many purposes. Embedded fabric can strengthen
a part’s tensile strength which will allow it to
withstand harsh applications. It also can be used
on a part’s surface to reduce coefficient of
friction.
Multi-Laminate - Multi-laminate designs are
used in severe applications where part failure
must be minimized. Aerospace applications use a
multi-laminate construct of fabric, silicone, and
polyester. The fabric reduces the part’s coefficient
of friction and the rigid polyester molded insert
ensures that the part does not pull out of its
retainer.
8
Pawling Custom Rubber and Plastic Products
Finishing Options
Butt Splice - Butt Splices are the most common
method to finish an extrusion into a gasket or
seal. Some materials can be heat welded while
others need to be vulcanized. Extruding and butt
7splicing is usually more cost effective than fully
molding a part.
Mitre Splice - Applications requiring a picture
frame configuration can be spliced using a 45
degree mitre to form the frame.
Molded Corners - When function and reliability
must be optimized, corners are molded separately
then butt spliced into a frame. This process moves
the vulcanized splice away from the corner, which
makes it stronger. Molded corners can be designed
for gentle radii up to a full square.
Notched Corners - Notched corners employ
aspects of the mitre splice, but accomplish it
without having to fully cut the extrusion. This
method works particularly well with P-strip or
J-seal designs (see page 14).
Notching/Punching/PSA Application - Whether
in-line or as a secondary operation, parts can be
notched, punched, or PSA (pressure sensitive
adhesive tape) can be applied to improve
functionality.
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9
Available Materials
The appropriate thermoset and/or thermoplastic material is determined primarily by the function of your finished product. Durability,
flexibility, and strength vary with the type of plastic or rubber
chosen. We continue to broaden our range of material capabilities to
better address our customers’ needs and keep a close eye on newly
available materials. Please contact us if you have more specific
requests. Our Sales Engineers will be happy to assist you.
Thermoplastic
Common Name/ASTM Designation
Chemical Name
TPE
(TPV)
Alcryn
TPU
Flexible PVC
(Vinyl)
Rigid PVC
(Vinyl)
Thermoplastic
Elastomer
Melt Processible
Rubber
Thermoplastic
Urethane
Polyvinylchloride
(Flexible)
Polyvinylchloride
(Rigid)
30-90
40-95
60-85
60-96
Hardness Range
Shore A
Shore D
75-82
Rockwell
Specific Gravity
0.87-1.35
1.10-1.17
1.14-1.19
1.37-1.45
1.33-1.41
Tensile Strength, psi
500-3000
1200-1900
3300-5600
1300-3000
6000-6600
Elongation%
210-600
200-500
620-870
240-430
0-54
200-500
n/a
n/a
Flexural Modulus, psi
Notched Izod Impact, ft.lbs./in.
4-20
Abrasion Resistance
VG
VG
E
G
VG
Water Resistance
E
E
G
E
E
Ozone Resistance
E
E
E
E
E
VG-E
E
F-G
G
G
Acids
E
E
F
G
G
Alkali
E
E
F
G
G
Oil
F
E
G
F
F
Weather (UV)
Gas Permeability
F
G
F
F
F
Heat Aging
G
G
G
F
F
Low Temperature
G
E
VG-E
G
F
n-Hexane
G
E
G
P
P
Xylene/Toluene (RT)
F
P
P
P
P
Methylethylketone (RT)
G
P
P
P
P
Trichloroethylene
P
P
P
P
P
Gasoline
P
G
G-VG
F
F
2.5% Detergent Solution
E
E
VG
E
E
Antifreeze
G
G
G
P
P
Dioctyl Phthalate
E
n/a
E
P
P
Ethyl Alcohol
VG
G
F
G
G
E = Excellent
10
395,000-400,000
Pawling Custom Rubber and Plastic Products
VG = Very Good
G = Good
F = Fair
P = Poor
Thermoset
Common Name
EPDM or EP
Rubber
Neoprene
SBR
Nitrile
(Buna-N)
Natural
Rubber
Butyl
Silicone
Fluorosilicone
Fluorocarbon
Chemical Name
Ethylene
Propylene
Chloroprene
Styrene
Butadiene
Acrylonitrile
Butadiene
Natural
Isoprene
Isobutylene
Isoprene
Silicone
Fluorosilicone
Fluorocarbon
*(Viton®)
EP
CR
SBR
NBR
NR
IIR
VMQ
FVMQ
FKM
ASTM Designation
Hardness Range
40-90
20-80
40-90
50-95
50-70
40-75
40-80
40-70
70-90
Tensile Strength, psi
>2000
>2000
>2000
>2000
>2000
>2000
>1200
>1200
>1400
G
G
F
F
G
G
F
P
P
Tear Resistance
Abrasion Resistance
G-E
VG
G-E
G
E
G
P
F
G
Compression Set
G
G
G
G
E
F
VG
E
E
Resilience Cold
G
G
G
F
G
P
E
G
F
Resilience Heat
VG
VG
G
G
F
VG
E
E
E
Radiation Resistance
E
G
n/a
P
F-G
G
G
E
E
Impermeability to Gases
G
G
F
G
F
E
F
F
E
Dielectric Strength
E
VG
G
P
E
G
G
G
VG
Electrical Insulation
G-E
F-G
G
P
G-E
G
E
E
G
Adhesion to Metals
G
E
E
E
E
G
E
E
F-G
Adhesion to Fabrics
G
E
G
G
E
G
E
E
G
Acid Resistance
Mild Dilute
E
E
F-G
F-G
P-F
E
E
E
E
Strong Concentrated
G
G
F-G
F-G
P
G
F
G
E
Aliphatic Hydrocarbons
P
F-G
P
E
P
P
P
G
E
Aromatic Hydrocarbons
P
P
P
P
P
P
P
E
E
Oxygenated (Ketones, etc.)
G
P
P
P
P
G
P
F
F
Solvent Resistance
Resistance To:
Swelling in Lubricating Oil
P
G
P
VG
P
P
P
E
E
Oil and Gasoline
P
G
P
E
P
P
F
G
E
Animal Oils
F
F
P
E
P
F
G
E
E
Water Absorption
VG
G
VG
VG
VG
VG
E
E
E
Oxidation
E
VG
F
G
P-F
E
E
E
G
Ozone
E
VG
P
F
P-F
F-G
E
E
E
Sunlight Aging
E
VG
P
P
P-F
VG
E
E
G
Heat Aging
VG
G
G
G
F-G
G
E
E
E
Low Temperature
VG
G
VG
F-G
G
G
E
G
F
Flame
P
G
P
P
P
P
F
E
E
Vegetable Oils
F
G
P
G
P
F
P
E
E
Chlorinated Hydrocarbons
P
P
P
F
P
P
P-F
F
G
G = Good
F = Fair
E = Excellent
*Viton® is a trademark of E.I. Dupont Demours and Co.
VG = Very Good
P = Poor
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11
Tolerance Data
Because of rubber’s variability from lot to lot, rubber
manufacturers use these tolerances in order to ensure part
conformity.
Standard Extruded Cross Sectional Tolerances
(Metric Units)
RMA Class
Drawing Designation
Standard Extruded Cross Sectional Tolerances
(English Units)
1
High
Precision
2
Precision
3
Commercial
E1
E2
E3
Dimensions (mm)
RMA Class
Drawing Designation
2
Precision
3
Commercial
E1
E2
E3
Dimensions (inches)
Above
Up To
+/-
+/-
+/-
Above
Up To
+/-
+/-
+/-
0
1.5
0.15
0.25
0.40
0
0.06
0.006
0.010
0.015
1.5
2.5
0.20
0.35
0.50
0.06
0.10
0.008
0.014
0.020
2.5
4.0
0.25
0.40
0.70
0.10
0.16
0.010
0.016
0.027
4.0
6.3
0.35
0.50
0.80
0.16
0.25
0.014
0.020
0.031
6.3
10
0.40
0.70
1.00
0.25
0.39
0.016
0.027
0.039
10
16
0.50
0.80
1.30
0.39
0.63
0.020
0.031
0.051
16
25
0.70
1.00
1.60
0.63
0.98
0.027
0.039
0.063
25
40
0.80
1.30
2.00
0.98
1.57
0.031
0.051
0.079
40
63
1.00
1.60
2.50
1.57
2.48
0.039
0.063
0.098
63
100
1.30
2.00
3.20
2.48
3.94
0.051
0.079
0.126
Cut Length Tolerances for Unspliced Extrusion
(Metric Units)
RMA Class
Drawing Designation
Cut Length Tolerances for Unspliced Extrusion
(English Units)
1
High
Precision
2
Precision
3
Commercial
L1
L2
L3
Dimensions (mm)
RMA Class
Drawing Designation
1
High
Precision
2
Precision
3
Commercial
L1
L2
L3
Dimensions (inches)
Above
Up To
+/-
+/-
+/-
Above
Up To
+/-
+/-
+/-
0
40
0.70
1.00
1.60
0
1.60
0.03
0.04
0.06
40
63
0.80
1.30
2.00
1.60
2.50
0.03
0.05
0.08
63
100
1.00
1.60
2.50
2.50
4.00
0.04
0.06
0.10
100
160
1.30
2.00
3.20
4.00
6.30
0.05
0.08
0.13
160
250
1.60
2.50
4.00
6.30
10.00
0.06
0.10
0.16
250
400
2.00
3.20
5.00
10.00
16.00
0.08
0.13
0.20
400
630
2.50
4.00
6.30
16.00
25.00
0.10
0.16
0.25
630
1000
3.20
5.00
10.00
25.00
40.00
0.13
0.20
0.40
1000
1600
4.00
6.30
12.50
40.00
63.00
0.16
0.25
0.50
1600
2500
5.00
10.00
16.00
63.00
100.00
0.20
0.40
0.63
2500
4000
160.00
4000
6.30
12.50
20.00
100.00
0.16%
0.32%
0.50%
160.00
Tolerance Tables and Glossary of Terms are courtesy of the Rubber Manufacturers Association (RMA).
For more information, please visit their web site at www.rma.org.
12
1
High
Precision
Pawling Custom Rubber and Plastic Products
0.25
050
0.80
0.16%
0.32%
0.50%
Glossary of Terms
Abrasion Resistance - The resistance of a material to
loss of surface particles due to friction. When high
abrasion resistance is required, Polyurethane (either
thermoset or thermoplastic) is preferred.
Autoclave - A pressure vessel into which materials or
articles can be placed and exposed to steam under
pressure. It is commonly used to vulcanize carbon-based
polymers, like EPDM, CR, Nitrile, and SBR.
Butt Joint - A joint made in a rubber part before or after
vulcanization by placing the two pieces to be joined
edge-to-edge. A butt joint is preferred over a mitered
joint as the butt joint is typically stronger.
Compression Set – The residual deformation after
removal of the force which has subjected the specimen to
compression. Compression set is a key factor when
designing a part that will be compressed for long periods
of time.
Creep - The deformation, in either cured or uncured
rubber under stress, which occurs with lapse of time after
the immediate deformation.
Durometer – An instrument for measuring the indentation hardness of rubber; also, sometimes used as a synonym for hardness. For thermoset rubber and
thermoplastic vulcanizate (TPV) materials, durometer is
defined using the Shore A scale where the lower the value
the softer the material.
Elongation – The maximum elongation prior to rupture.
Friction - Produced from the interference of two surfaces
brought together. Parts in light friction will slide along
each other easily but as friction is increased sliding
becomes more difficult.
Microwave Curing - Heating a thick cross section
uniformly is difficult using conventional ovens. Microwave
technology however is not affected by dimensional
considerations as the microwaves rapidly heat the insides
and outsides of a profile simultaneously. A typical
microwave extruder has a microwave unit at the end of
the extruder to rapidly heat the extrusion and a HAV unit
following to maintain temperature while vulcanizing.
A significant benefit gained from microwave curing is that
extremely long lengths can be achieved.
Modulus – The tensile strength recorded when the
specimen is elongated 100%. For dynamic properties
where the part will be stretched and compressed
continually, a high modulus is preferred.
Permeability - To permit passage of gas through the
molecular structure of a given material. Materials with
low permeability, such as Butyl or FKM, are preferred in
vacuum applications.
Tear Strength – The maximum load required to tear apart
a specimen; the acting substantially parallel to the major
axis of the test specimen. For applications where the part
may experience some shearing action, a high tear material is preferred.
Tensile Strength – The maximum tensile stress applied
during stretching a specimen to rupture. The higher the
tensile strength, the stronger the material.
Vulcanization – An irreversible process during which a
rubber compound through a change in its chemical
structure (for example, cross-linking) becomes less
plastic and more resistant to swelling by organic liquids
and elastic properties are conferred, improved, or
extended over a greater range of temperature.
Low Temperature Flexibility - The ability of a rubber
product to be flexed, bent, or bowed at specified low
temperature without loss of serviceability. Silicone is
typically the polymer of choice when low temperature
flexibility must be maintained.
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13
Standard Cross Sections and Stocked Profiles
“P” and “J” Seals
1”
1/2”
1/4”
1 1/4”
1 1/4”
PR13540 (CR, VMQ)
1”
PR13542 (CR, VMQ)
5/16”
2 1/2”
3”
PR23333 (EP)
PR15782 (CR)
5/8”
3/8”
3/8”
1 1/4”
3/4”
1 1/8”
X21339 (CR)
PR13541 (EP, CR, VMQ)
1 3/4”
PR28910 (NBR)
11/16”
5/16
7/8
X21337 (CR)
4”
1 1/2”
PR18156 (CR)
1/2”
6”
PR15480 (EP)
1”
1/2”
1/4”
2 1/4”
1 1/8”
1 3/4”
PR19491 (FVMQ)
PR5919 (CR)
3/8”
1/2”
4”
7/8”
PR15415 (CR)
1 1/2”
X21338 (CR)
1/2”
6”
PR16448 (CR)
14
Pawling Custom Rubber and Plastic Products