Specifications
for Pressure Sensitive Adhesive Labels for Application to Plastic
and Metal Substrates for Use in Thermal Transfer Printers
Specification Number 700-713-1/12/00
This specification is provided as a public service by the Preservation
Directorate of the Library of Congress. Any commercial reproduction
that implies endorsement of a product, service or materials, in any
publication, is strictly prohibited by law. This Specification is written
for L.C. purchasing purposes and is subject to change when necessary.
I. General Specifications - II.
Product Requirements - III. Inspection
A. Face Stock
- Composition Options
- Polyester: White opaque film, 1-2 mil thick.
The polyester must be biaxially oriented, non-recycled film with
no plasticizers added.
- Polypropylene: White opaque film, 1-2 mil thick.
Biaxial orientation preferred.
The Procurement Request will clearly identify which of these face
stock materials is to be used for the particular application intended
by the purchaser.
- Degree of Whiteness
White pigmented label face stocks must have a minimum brightness
of 82% as measured by directional reflectance at 457 nm (TAPPI T452
cm-92).
- Brightness Retention
Accelerated Aging: The
color of the face stock must not change more than 10 points of brightness
as measured by
directional reflectance at 457 nm when exposed for 28 days at 90°C
and 50% RH. The brightness will be measured according to TAPPI T452
cm-92.
Photo Degradation: The color of the face stock
must not change more than 10 points of brightness as measured by
directional reflectance at 457 nm when exposed 24 hours to a Xenon
arc lamp in an Atlas Weatherometer under the following conditions:
Irradiance Level: 1.0 watts/m2 at 420 nm. Inner filter:
Borosilicate glass. Outer filter: clear soda lime glass. Black panel
temperature:
50°C. Wet bulb depression: 8.5°C. The brightness will be
measured according to TAPPI T452 cm-92.
B. Adhesive
- Composition
The pressure-sensitive adhesive layer must possess high permanence
characteristics such that labels, once applied, remain attached permanently
and can be removed only with difficulty. The adhesive must be clearly
identifiable as an acrylic polymer or copolymer its infrared spectrum.
- Bond Strength
The adhesive must demonstrate sufficient initial bond strength
for the label to support a test weight of 200g for 10 minutes.
Test Method: This procedure is a 90-degree peel
test modified from ASTM D2860M-90. The bonding strength of the adhesive
to plastic and metal substrates is assessed. Test Panels used in
this test, are designated LC Standard Test Panels PM-1 (polypropylene),
PM-2 (polyester), PM-3 (polystyrene), PM-4 (high-density polyethylene),
PM-5 (polyvinyl chloride), PM-6 (stainless steel), and PM-7 (brushed
aluminum.) The materials used for these LC Standard Test Panels have
been selected to represent the wide range of non-book media in any
large collection.
For a collection consisting of mixed media this
peel test is performed on a single substrate, LC Standard Test Panel
PM-1. For collections
consisting of only one type of media the label need only be tested
on that particular substrate, using one of the other LC Standard
Test Panels in place of LC Standard Test Panel PM-1.
A set of
three labels, size 1" x 2 1/2", is applied to the selected
LC Standard Test Panel over a Mylar window that permits only a one
inch square area of the adhesive side of the label to be in contact
with the substrate, as illustrated in ASTM D2860M-90, procedure B.
The labels are set in place by applying firm pressure with the edge
of a 3M plastic applicator, model no. P.A.-1, to the labels in four
downward strokes. The test samples are then allowed to cure for 7
days in an environmental chamber conditioned to 73°F and 50%
RH.
At the end of this dwell time a 200 gram weight is suspended from
the free end of the label and timed for 10 minutes. At the end of
this test period, labels must not have peeled away from the substrate
by more than 10 millimeters. Failure of this test with any of the
four test panels will disqualify the stock and no further testing
need be performed.
- Bond Strength after Accelerated Aging
The adhesive, once set after the initial 7-day dwell time, must
remain permanently affixed to both the face stock and the substrate
with no loss of adhesive strength for the life of the object to which
it is applied, under conditions of normal use.
Test Method: This procedure is a 90-degree peel
test, modified from ASTM D2860M-90.
A set of three labels is applied
to the selected LC Standard Test Panel in the same manner as described
under Item 2 above. The labels
are then subjected to accelerated aging at 80°C and 50% RH for
28 days. At the end of the aging period the test samples are placed
in an environmental chamber conditioned to 73°F and 50% RH for
24 hours.
At the end of the conditioning period a 90° peel test
is performed as in Item 2 above.
At the end of this test period, labels
must not have peeled away from the substrate by more than 10 millimeters.
C. Other Label Properties
- Curling/Lifting/Ooze
The labels must not show any sign of curling, lifting, buckling,
or puckering, nor any evidence of the adhesive oozing beyond the
label edges. In addition, there must be no evidence of any damage
to the substrate, such as corrosion of metals or discoloration.
Test Method: A
set of three labels, size 1 1/4" x
1 1/4", is applied to the selected LC Standard Test Panel so that
the entire adhesive side of the label is in contact with the substrate.
The labels are set in place by applying firm pressure with the edge
of a 3M plastic applicator, model no. P.A.-1, to the labels in four
downward strokes.
The labels are then subjected to accelerated aging
at 80°C
and 50% RH for 28 days. At the end of the aging period aging, the
labels are examined visually.
- Blocking to Adjacent Substrates
The label, once applied, must not block to adjacent substrates
when stored under ambient conditions.
Test Method: This procedure is modified from ASTM
D1146-88.
For a collection consisting of mixed media this test is
performed using LC Standard Test Panel PM-2. On two separate pieces
each of
LC Standard Test Panel PM-2 a set of three labels, size 1 1/2 " x
1 1/2", is applied so that the entire adhesive side of the label
is in contact with the substrate. The labels are set in place by
applying firm pressure with the edge of a 3M plastic applicator,
model no. P.A.-1, to the labels in four downward strokes.
For collections consisting of only one type of media the label
need only be tested on that particular substrate, using one of
the other LC Standard Test Panels in place of LC Standard Test
Panel PM-2.
The labeled Test Panels are each faced with a clean
Test Panel in a stack so that the label face stock is in contact
with the facing
Test Panel. Each stack is held in place by a 1 lb. weight. One Test
Panel stack is subjected to conditions of 60°C and 80% RH for
24 hours to test for hygroscopic blocking. The second Test Panel
stack is subjected to conditions of 60°C in a dry oven for 24
hours to test for thermoplastic blocking.
Second degree blocking,
as defined in ASTM D1146-88, or signs of adhesive transfer to the
adjacent substrate, constitute a failure.
- Print Fastness
The label stock must be able to accept and retain a clean, legible
image from a thermal transfer printer.
The label stock will be printed
with a test pattern consisting of a sample phrase or barcode centered
on each label using a printer
selected by the Library. The printer model to be used in this test
will be noted on the purchase order. Inability to print the stock
on the selected printer, obtain a clear, crisp and complete image,
or read the barcode with a scanner will constitute a failure. Any
failure of the label stock during the printing process will disqualify
the stock and no further testing will be performed.
Test Method: A
strip of 3M Tape #230 is applied over the printed test pattern on
the label by rubbing down the tape
using three fingers in six firm strokes. The tape is then peeled
back at a 180° angle. Legible characters visible on the test
tape, and/or degradation of the printed image on the face stock,
constitute a failure. (This method is described in Archival Copies
of Thermofax, Verifax and Other Unstable Records, Technical
Information Paper No. 5, Washington, D.C., National Archives and
Records Administration, 1990).
- Abrasion Resistance of Printed Image
The printed image on the label must be able to resist moderate
abrasive forces with minimal smudging of the ink.
Test Method: This procedure follows ASTM D5264-92.
Printed
labels are attached to a piece of LC Standard Test Paper P-1 which
has been cut to fit the base of the Sutherland Rub Tester.
The test specimen is placed on the rubber pad on the base of the
Sutherland Rub Tester, as described in ASTM D-5264 92, printed side
facing the receptor block. The test specimen is then rubbed for 20
strokes using the A-1 Standard Receptor, Imperial Lapping Film with
aluminum oxide 9-µm particles.
The extent of smudging is evaluated
by selecting an area of the greatest density of smudged ink, 3-5
mm away from a printed character,
and measuring its optical density using a reflectance densitometer.
The density of the smudged area is compared to the density of a clean,
unprinted, area of the label stock.
Density changes above 0.03 constitute
a failure.
- Effect on Photographic Material
If specified on the purchase order for use with collections of
photographic materials, the labels must pass the Photographic Activity
Test. Both the face stock and adhesive side of the label will be
tested. Test to be conducted and results reported as described in
ANSI IT9.16-1994, or latest revision. This test can be performed
by the Image Permanence Institute (c/o Rochester Institute of Technology,
Frank E. Gannett Memorial Building, P.O. Box 9887, Rochester, NY
14623-0887. Tel.: 716-475-5199, FAX: 716-475-7230) or other pre-approved
laboratory.
- Suitability for Cold Storage
The labels must be able
to pass all of the tested properties listed above after being exposed
to conditions of 0°C for 24 hours,
followed by 24 hours at 73°F and 50% RH.
A. Thermal Transfer Ribbon Compatibility
The label stock must be compatible with hard-resin thermal transfer
ink ribbons. Wax ribbons or wax-resin ribbons are not acceptable. The
vendor must recommend compatible printing ribbons for the label stock,
provide specification sheets (and/or performance data), a sample to be
used in the printer for use in testing, and purchasing information for
each ribbon recommended.
B. Odorlessness
The label stock must not emit odors deemed objectionable or hazardous
to the work environment by the Library of Congress according to TAPPI
T483.
C. Liner
The release liner under all label configurations must allow for easy
and complete peeling of the face stock without shearing of the adhesive
layer.
D. Workmanship
All label edges will be cut square and clean, and sizes accurate to
specification.
E. Shelf-Life
The adhesive must have a one year usable shelf-life such that the initial
adhesion strength will be the same for labels applied up to one year
after the original delivery date under ambient storage conditions. The
labels must also maintain their capacity to be printed upon.
F. Dimensions
Dimensions will be specified on the purchase order.
G. Packaging
The items must be packed in standard commercial containers which are
constructed to ensure that they are received in perfect condition - dry,
undamaged and without kinks or creases. The outside of each container
must be identified by type, size and number of items within, manufacturing
run or batch number and Purchase Order number or Contract number.
A. Testing
- Responsibility
The supplier is responsible for meeting all the requirements specified
herein. The Library of Congress has the right to perform any of the
tests set forth in the specification where such tests are deemed
necessary to ensure that supplies conform to prescribed requirements.
- Sampling
To sample for testing, shipments will be sampled according to MIL-STD-105E
at inspection level S-2 with an acceptable quality level of 2.5 percent
defective from each lot offered. Copies of MIL-STD-105E are available
from Naval Publications and Forms Center; Standardization Document
Order Department, Building 4, Section D; 700 Robbins Avenue; Philadelphia,
Pennsylvania 19111-5094.
- Materials
The following materials are required to perform the tests in this
specification:
LC Standard Test Panel PM-1
LC Standard Test Panel PM-2
LC Standard Test paper P-1
Polyester (Mylar D)
3M Tape #230
3M Imperial Lapping Film, aluminum oxide 9-µm particles
Carey Lea Silver Test Film
Elite Photographic Paper
Whatman No. 1 filter paper
- Methods
Tests will be conducted in accordance with specified test methods
of the American National Standards Institute (ANSI), the American
Society for Testing and Materials (ASTM), and the Technical Association
of the Pulp and Paper Industry (TAPPI) and/or as described. Publications
describing these tests may be ordered directly from the technical
associations:
- ANSI, 1430 Broadway, New York, NY 10018
- ASTM, 100 Barr Harbor Drive, W. Conshohocken, PA 19428-2959
- TAPPI, One Dunwoody Park, Atlanta, GA 30348
- Tests
Requirements
|
Test Method |
Brightness, initial |
> 82% |
TAPPI T452 om-92 |
Brightness, after aging |
< 10 pts. change |
TAPPI T452 om-92 |
Photo Degradation |
< 10 pts. change |
TAPPI T 452 om-92 |
Adhesive ID |
acrylic |
infrared spectrum |
Bond Strength |
200g, < 10 mm peel |
ASTM D2860M-90 (modified) |
Bond Strength - Aged |
200g, < 0 mm peel |
ASTM D2860M-90 (modified), after aging |
Curling/Lifting/Ooze |
none |
visual, after aging |
Blocking |
no second degree blocking |
ASTM 146-88 |
Print Fastness |
no legible characters on tape |
NARA Technical Information Paper No. 5 |
Print Abrasion |
< 0.03 pts. density change |
ASTM D5264-92 |
PAT |
pass |
ANSI IT9.16-1994 |
FAILURE TO MEET ANY OF THE SPECIFICATIONS WILL BE CAUSE FOR
REJECTION.