ASTM D2851-98(2004)
(Specification)Standard Specification for Liquid Optical Adhesive
Standard Specification for Liquid Optical Adhesive
ABSTRACT
This specification covers liquid optical adhesive for use in bonding glass to glass or other transparent adherends. The adhesive shall be in liquid form and free of solvent in order to avoid bubble formation in the adhesive layer. Each component shall be completely reactive. The adhesive may be heat-, catalyst-, or radiation-cured. Voltatility, color, viscosity, foreign particle content, refractive index, stability, light transmission, glass doublet preparation, environmental test, and bond strength tests shall be performed in accordance with the specified requirements.
SCOPE
1.1 This specification covers liquid optical adhesive for use in bonding glass to glass or other transparent adherends.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information purposes only.
1.3 The following precautionary caveat pertains only to the test method portion, Section 6, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in 6.1.1.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D2851 – 98 (Reapproved 2004)
Standard Specification for
Liquid Optical Adhesive
This standard is issued under the fixed designation D2851; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Bond strength data may be suitable for specification accep-
tance, service evaluation, manufacturing control, research, and
1.1 This specification covers liquid optical adhesive for use
development.Bondstrengthtestsarenotconsideredsignificant
in bonding glass to glass or other transparent adherends.
for applications differing widely from the test in rate and type
1.2 The values stated in SI units are to be regarded as
of loading.
standard. The values given in parentheses are provided for
information purposes only.
5. General Requirements
1.3 The following precautionary caveat pertains only to the
5.1 The adhesive shall be in liquid form and free of solvent
test method portion, Section 6, of this specification: This
in order to avoid bubble formation in the adhesive layer. Each
standard does not purport to address all of the safety concerns,
component shall be completely reactive (without residual
if any, associated with its use. It is the responsibility of the user
volatile products). The adhesive may be heat-, catalyst-, or
of this standard to establish appropriate safety and health
radiation-cured.
practices and determine the applicability of regulatory limita-
5.1.1 Volatility—Volatile content of the adhesive shall not
tions prior to use. Specific precautionary statements are given
exceed 0.5%, unless otherwise agreed upon between the
in 6.1.1.
manufacturer and the purchaser.
2. Referenced Documents 5.1.2 Viscosity—The viscosity of the adhesive shall be
within a well-defined range as agreed upon between the
2.1 ASTM Standards:
manufacturer and the purchaser.
D542 Test Method for Index of Refraction of Transparent
5.1.3 Color—The color of the adhesive shall not exceed the
Organic Plastics
color of a platinum-cobalt standard solution No. 300.
D897 Test Method for Tensile Properties of Adhesive
5.1.4 Cleanliness—Thenumberandsizeofforeignparticles
Bonds
foundin100mLoftheadhesiveshallnotexceed5particlesin
D904 Practice for Exposure of Adhesive Specimens to
the size range from 10 to 100 µm (0.1 mm), and none larger
Artificial Light
than 100 µm. The number and size of foreign particles in the
D907 Terminology of Adhesives
catalyst required to cure 100 mL of the adhesive shall not
D1084 Test Methods for Viscosity of Adhesives
exceed 2 particles in the size range from 10 to 100 µm, and
E308 Practice for Computing the Colors of Objects by
none larger than 100 µm.
Using the CIE System
5.1.5 Refractive Index—The refractive index of the cured
3. Terminology
adhesive shall be within a well-defined range as agreed upon
between the manufacturer and the purchaser.
3.1 Definitions—Many terms in this specification are de-
5.1.6 Stability—The liquid adhesive shall not change in
fined in Terminology D907.
viscosity by greater than 20% of its original viscosity nor
4. Significance and Use
show any formation of solids, when tested as described in 6.6.
5.1.7 Light Transmission—Visible light transmission
4.1 The bond strength tests provide reasonably accurate
through a bonded glass doublet (two glass disks bonded as
information with regard to the bond strength of the adhesives.
described in 6.8) shall not be less than 98.5% of the total light
transmitted through a single glass disk. There shall be no
This specification is under the jurisdiction of ASTM Committee D14 on
change in light transmission of a glass doublet after the
Adhesives and is the direct responsibility of Subcommittee D14.60 on Adhesive
environmental test (see 6.9).
Material Classification System.
Current edition approved April 1, 2004. Published April 2004. Originally 5.1.8 Environmental Test—Separation within the adhesive
approved in 1970. Last previous edition approved in 1998 as D2851–98. DOI:
layer or from either glass surface of the glass doublet shall not
10.1520/D2851-98R04.
exceed 1.0 mm in depth nor extend beyond 180° of the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
periphery of the adhesive layer (see 6.9).
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D2851 – 98 (2004)
5.1.9 Bond Strength—Thetensilestrengthofabondedglass
Pt-Co Stock Solution Distilled H O
doubletafterbeingsubjectedtotheenvironmentaltest(see6.9)
Number of Pt-Co 500, mL to Be Added, mL
shall be greater than 200 psi (1.38 MPa) or any value agreed
500 100 0
upon between the manufacturer and the purchaser. 450 90 10
400 80 20
350 70 30
6. Test Methods
300 60 40
250 50 50
6.1 Volatility:
200 40 60
150 30 70
6.1.1 Thoroughly clean three petri dish bottoms, 95-mm
100 20 80
outsidediameter,bywashingwithdetergentandascrubbrush.
75 15 85
50 10 90
Rinse with warm running tap water. Place petri dishes in an
0 0 100
air-circulatingovenfor30minat65 62°C(150 64°F).Raise
temperature to 110 6 2°C (230 6 4°F) for 1 h. Remove petri
Store the stock solutions in clean glass bottles and stopper
dishes from oven and place in a desiccator. After petri dishes
them to prevent evaporation loss.
have cooled to room temperature, approximately 2 h, weigh
6.4 Foreign Particle Content—Inspect a 100-mLsample of
each dish to the nearest 0.1 mg. (Warning—In addition to
the liquid adhesive and a sample of its catalyst for cleanliness
other precautions, do not handle petri dishes with bare hands.
byfilteringeachthroughalow-formGoochcruciblefittedwith
Use tongs.)
a filter membrane of 5.0 to 10.0-µm pore size and a color
6.1.2 Replace each petri dish in the oven at 110 6 2°C (230
suitabletoeasilydetectandexamineforeignparticles.Measure
6 4°F) for 1 h. Repeat cool-down procedure. Reweigh each
the size of the particles by means of a calibrated traversing
petridishtothenearest0.1mg.Ifweightagreestowithin 60.2
microscope (103) or other equivalent means. If the viscosity
mg of initial weight, proceed to 6.1.3. If weight exceeds this
of the sample is too high, dilute it with any clean and suitable
60.2-mgrange,repeatprocessuntilaconstantweightforeach
solvent to permit easy flow of the liquid through the filter
petri dish is obtained.
membrane.
6.1.3 Toeachpetridishaddapproximately10
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