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WHEATON
800.225.1437 (U.S. & Canada Only) | 856.825.1100 | 856.825.1368 (F) |
www.wheaton.comClosure Liner Guide
Usually the smallest component part of the package and usually overlooked is the selection of the closure liner. The liner must not alter or be altered by the product. It must withstand
repeated applications and removals against the container surface while maintaining the integrity of the sealing surface. Below is information that may help in choosing the right liner
from the WHEATON product offering.
Pulp / Poly-Vinyl
General purpose: Suitable for wide range of applications. Chemical
resistance: Good for mild acids, alkalis, solvents, alcohols, oils and aqueous
products. Poor for active hydrocarbons and bleaches.
One mil poly-vinyl film bonded to one mil HDPE on a #30 white
pulp paper backing. Superior to plain pulp paper because it
provides an excellent moisture barrier.
Typical applications: analytical lab samples, high purity chemicals, strong
acids, solvents. Excellent for environmental samples, pharmaceuticals and
diagnostic reagents.
PTFE faced foamed polyethylene liner offers the excellent
chemical resistance of PTFE with the compressibility and
sealing properties of polyethylene foam.
PTFE Faced Foamed
Polyethylene (PTFE / PE Foam)
Unique problem solving type of liner. This liner is stress crack resistant and
offers superior torque retention and excellent sealing characteristics. It is
recommended that this liner be tested prior to use for leak seal.
Manufactured from polyethylene (LDPE). The unique cone
design provides a wedge type seal that not only seals across
the top but also across the inside diameter.
Excellent properties of resilience, resistant to moisture vapor. Satisfactory
for most moderate chemicals. Not good for oils, strong acids and
hydrocarbons. Not a natural rubber. Autoclavable.
The 14B white rubber lining material consists of homogeneous
sulfur cured styrene-butadiene rubber. FDA Status complies with
21CFR 177.26, “Rubber articles intended for repeated use.”
Styrene-Butadiene
Rubber (14B)
Designed for the ultimate in product safety. PTFE provides a totally inert
inner seal and surface facing the sample or product. Autoclavable.
The white rubber / 0.005" PTFE liner consists of virign PTFE
bonded to the white sulfur cured styrene-butadiene rubber.
Complies with the FDA 21CFR 177.1550.
Styrene-Butadiene Rubber
/ 0.005 PTFE
(PTFE / Styrene-Butadiene)
Note: Closures and liners are designed for a variety of applications. Product performance can vary depending on conditions. It is recommended that proper tests be performed to determine
the best liner for the application.
Foamed Polyethylene
(PE Foam)
Torque for Screw Closures
The integrity of the closure-to-container seal is dependent upon a number of variables, such as the materials of the closure, liner, and container, the sealing surface of the container, and
the application torque applied to the closure. The most important of these is the application torque. If the closure is applied too loosely, the contents could leak, especially during shipping.
If the closure is applied too tightly, it may be too difficult to remove, or the container could break during application.
Table 2
offers some suggested torques that should provide an adequate seal for most applications. It is recommended that proper tests be performed to determine the optimum torque for
the application. The most practical way to check the tightness is to measure the removal torque after the closure has been on the container for about 5 minutes. The removal torque should
closely approximate the application torque. The minimum removal torque noted in the table should be maintained after a 24 hour period.
Closure
Application
Min Removal
Application
Min Removal
Application
Min Removal
Application
Min Removal
mm
Torque
Torque
Torque
Torque
Torque
Torque
Torque
Torque
15
8
4
6
3
12
7
8
4
18
9
5
7
4
13
8
9
5
20
10
5
8
4
15
9
10
5
22
11
6
9
5
17
10
11
5
24
12
6
10
5
18
11
12
6
28
14
7
12
6
21
12
14
7
33
18
9
15
7
24
14
17
8
38
20
10
17
7
29
17
19
9
43
22
11
18
9
33
20
22
11
48
24
12
20
10
36
22
24
12
58
28
14
24
12
44
26
29
14
70
35
18
28
14
52
32
35
17
89
45
22
36
18
65
40
45
22
100
50
25
40
20
75
45
50
25
Although the information in this chart was acquired from reputable sources, it should only be used as a guide in determining the proper application torque. WHEATON accepts no responsibility for the accuracy of
this data or for any consequences resulting from its use.
Phenolic / Urea Closure
Phenolic / Urea Closure
PP / PE Closure
PP / PE Closure
on Glass Container
on Plastic Container
on Glass Container
on Plastic Container
Table 2. Suggested Torques for Closures
(in-lb)
General Purpose: Broad applications base. Chemical resistance-good for
acids, alkalis, solvents, alcohols, oils, household cosmetics and aqueous
products. Poor for hydrocarbon solvents. Liner provides tight seal.
A one piece, three ply coextruded liner consisting of both
foamed and solid LDPE. The foam core is sandwiched with solid
clear PE.
Pulp / Metal Foil
Aluminum foil bonded to pulp board.
Good barrier properties, good resistance to hydrocarbons, oils, ketones and
alcohols. Not good for acids or alkalis.
PTFE Faced Silicone
Rubber (PTFE / Silicone)
The liner consists of 0.005” thick PTFE bonded to 0.055” thick
silicone rubber.
Ideal for low temperature storage applications. PTFE facing provides
excellent chemical barrier. Autoclavable
Low Density Polyethylene
(LDPE)
Disk
Manufactured from polyethylene.
Good for distilled water, analytical standards and reagents.
Polyethylene Cone
(PE Cone)
> 172
Technical Data, Closures