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Specifications for Pressure Sensitive Adhesive Labels for Application to Plastic and Metal Substrates for Use in Laser Printers

Specification Number 700-703-9/5/00

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

I. GENERAL SPECIFICATIONS

A. Face Stock

  1. Composition Options
    1. Polyester: White opaque film, 1-2 mil thick. The polyester must be biaxially oriented, non-recycled film with no plasticizers added.
    2. 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.

  2. 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).
  3. 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

  1. 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 infra-red spectrum.
  2. 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), MM-1 (stainless steel), and MM-2 (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.
  3. 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

  1. 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.
  2. 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 60ºC and 80% RH for 24 hours to test for hygroscopic blocking. The second Test Panel stack is subjected to conditions of 60ºC 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.
  3. 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).
  4. 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 0.06 constitute a failure.
  5. 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.
  6. 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.

II. ADDITIONAL PRODUCT REQUIREMENT: Pressure Sensitive Adhesive Labels for Application to Plastic and Metal Substrates for Use in Laser Printers

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.

III. QUALITY ASSURANCE INSPECTION: Pressure Sensitive Adhesive Labels for Application to Plastic and Metal Substrates for Use in Laser Printers

A. Testing

  1. 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.
  2. 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.
  3. 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-mm particles
    • Carey Lea Silver Test Film
    • Elite Photographic Paper
    • Whatman No. 1 filter paper
  4. 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
  5. 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 APPI T 452 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
    Blocking no second degree blocking ASTM D1146-88
    Print Fastness no legible characters on tape NARA Technical Information Paper No. 5
    Print Abrasion < 0.06 pts. density change ASTM D5264-92
    PAT pass ANSI IT9.16-1994

FAILURE TO MEET ANY OF THE SPECIFICATIONS WILL BE CAUSE FOR REJECTION.