Specifications
for Pressure Sensitive Adhesive Labels for Application to Text Pages
of Bound Books for Use in Laser Printers
Specification Number 700-704-1/12/00
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.
-
Paper:
- pH: 8.0 - 9.5, (TAPPI T 509 om-88), cold extraction,
slurried pulp
- Alkaline Reserve: between 2 and 5% calculated
as calcium carbonate (ASTM D4988)
- Lignin: Kappa number of 5 or less (TAPPI T236
cm-85)
- Sizing: only neutral or alkaline sizing should
be used.
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° and 50% RH.
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 by its infra-red
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 two different substrates is assessed. These two test panels, designated
LC Standard Test Panels PP-1 and PP-2, consist of two different papers
applied to 3" x 6" sections of 60 pt. binder's board. The materials
used on these LC Standard Test Panels have been selected to represent
the surface characteristics of papers commonly found in General Collection
books.
A set of three labels, size 1" x 2 1/2", is applied to each of
the two Test Panels 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 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
two 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 each of the two Test Panels 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.
Test Method: A set of three labels,
size 1 1/4" x
1 1/4", is applied to LC Standard Test Panels PP-1 and PP-2 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, the labels
are examined visually.
- Migration and Staining
The label adhesive must not migrate into and discolor the substrate
and/or cause staining of the substrate after aging.
Test Method: One
label, size 1 1/4" x 1 1/4",
is applied to each of 5 separate strips of LC Standard Test Paper
P-3 (Whatman No. 1 filter paper) and LC Standard Test Paper P-4 (an
acidic newsprint paper) and aged at 80°C and 50% RH for 28 days.
After
aging, a fresh label is placed on the test paper alongside, but not
touching, the aged label. The side of the test paper behind
the labels is measured for brightness. The area behind the aged label
must not show any visual evidence of discoloration of the test paper
as compared to the paper behind the fresh label. Visual evidence
of discoloration, confirmed by a brightness change of more than 3
points, constitutes a failure. This brightness change must be clearly
attributable to discoloration of the paper substrate, rather than
to discoloration of the label face-stock or yellowing of the adhesive.
- Damage to Adjacent Pages
Neither the face-stock nor the adhesive must cause discoloration,
stick to, or otherwise cause damage to adjacent pages.
Test Method: One label is applied to each of five
strips of two different test papers, each measuring 22mm x 120mm.
The two test papers are LC Standard Test Paper P-2 (a clay-coated
alkaline paper) and P-3 (Whatman No. 1 filter paper). Each of these
labeled Test Papers is faced with one strip of the same paper, backed
up with 4 more strips of the same paper, so that the face-stock is
facing the first strip and is in contact with that strip.
Each stack
of samples of each of the two Test Papers is placed, together, in
a stainless steel test jig to hold the papers in the
stack. Each stack of paper is separated by a strip of polyester.
The stack of samples will be topped with a glass slat of the same
size as the strips. Enough stainless steel slats measuring 22mm x
120mm are placed on top of the glass slat to come to a total weight
(glass and metal) of 200g. The samples are then subjected to accelerated
aging at 90°C and 50% RH for 28 days.
At the end of the aging
period the labeled test strips must separate cleanly and easily from
the facing paper strips. First degree blocking,
as defined by ASTM D1146-88, is acceptable. However, if either the
face stock, or edge-ooze of the adhesive, has caused second degree
blocking, the label will fail the test.
The brightness of the facing
paper strips is measured according to TAPPI T452 cm-92. The brightness
of the area of the facing paper
strip which was in contact with the face-stock on the facing strip
is also measured. The two brightness measurements must not differ
by more than 3 points.
- Print Fastness
The label stock must be able to accept and retain a clean, legible
image from a laser 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 bar-code 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).
- Off-setting of Ink to Adjacent Pages
The printed image on the label must not rub off, transfer, or otherwise
disfigure the paper facing the label.
Test Method: A printed label is applied to each
of two different test papers, LC Standard Test Papers P-1 and P-3,
and tested by rubbing with that same Test Paper on a Sutherland Rub
Tester according to GPO Test Method P-11, Rub Resistance of the Printed
Image. Density changes of 0.04 or above, recorded on the receptor
stocks, constitute a failure. (This method is described in GPO Publication
310.1, Government Printing Office Contract Terms Quality Assurance
Through Attributes Program for Printing and Binding, December
1992 edition.)
- 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. Problem-free Print Feeding
The label sheet must lie flat without any curling and permit problem-free
self-feeding from a stacking paper tray.
B. Non-contamination of Printer by Adhesive Residue
The labels must not transfer adhesive to the platens or any other parts
of a laser printer under extended, but normal use. There must not be
any adhesive deposits on the platens or other accessible parts of the
printer that can be seen visibly or felt by stickiness to the touch.
C. 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.
D. 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.
E. Workmanship
All label edges will be cut square and clean, and sizes accurate to
specification.
F. 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.
G. Dimensions
Dimensions will be specified on the purchase order.
H. 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 PP-1
LC Standard Test Panel PP-2
LC Standard Test Paper P-1
LC Standard Test Paper P-2
LC Standard Test Paper P-3
LC Standard Test Paper P-4
Polyester (Mylar D)
3M Tape #230
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 |
pH (paper face-stock) |
8.0-9.5 |
TAPPI T509 om-88 |
Alkaline Reserve (paper) |
2-5% |
ASTM D4988 |
Lignin (paper) |
Kappa < 5 |
TAPPI T236 cm-85 |
Brightness, initial |
> 82% |
TAPPI T452 om-92 |
Brightness, after aging |
< 10 pts. change |
TAPPI T452 om-92 |
Adhesive ID |
acrylic |
infra-red spectrum |
Bond Strength |
200g, < 10 mm peel |
ASTM D2860M-90 (modified) |
Bond Strength - Aged |
200g, < 10 mm peel |
ASTM D2860M-90 (modified), after aging |
Curling/Lifting/Ooze |
none |
visual, after aging |
Staining |
< 3 points |
TAPPI T 452 om-92, after aging |
Damage to Adjacent Pages |
no blocking; no discoloration |
TAPPI T 452 om-92, after aging |
Print Fastness |
no legible characters on tape |
NARA Technical Information Paper No. 5 |
Off-setting of Ink |
< 0.04 pts density |
GPO Test Method P-11 |
Photo Activity Test |
pass |
ANSI IT9.16-1994 |
FAILURE TO MEET ANY OF THE SPECIFICATIONS WILL BE CAUSE FOR REJECTION.