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Introduction
3M
Glass Bubbles are engineered hollow glass microspheres
that are alternatives to conventional fillers and additives such as
silicas, calcium carbonate, talc, clay, etc., for many demanding
applications. These low-density particles are used in a wide range
of industries to reduce part weight, lower costs and enhance
product properties.
The unique spherical shape of 3M glass bubbles offers a number
of important benefits, including: higher filler loading, lower
viscosity/improved flow and reduced shrinkage and warpage. It
also helps the 3M glass bubbles blend readily into compounds
and makes them adaptable to a variety of production processes
including spraying, casting and molding.
The chemically stable soda-lime-borosilicate glass composition
of 3M glass bubbles provides excellent water resistance to create
more stable emulsions. They are also non-combustible and non-
porous, so they do not absorb resin. And, their low alkalinity gives
3M glass bubbles compatibility with most resins, stable viscosity
and long shelf life.
3M Glass Bubbles K Series, S Series and iM Series are specially
formulated for a high strength-to-weight ratio. This allows greater
survivability under many demanding processing conditions, such
as injection molding. They also produce stable voids, which results
in low thermal conductivity and a low dielectric constant. 3M glass
bubbles are available in a variety of sizes and grades to help you
meet your product and processing requirements.
3M
Glass Bubbles
K Series, S Series and iM Series
Product Information
Product
Test Pressure
(psi)
Target Fractional
Survival
Minimum
Fractional
Survival
K Series
K1 250 90% 80%
K15 300 90% 80%
K20 500 90% 80%
K25 750 90% 80%
K37 3,000 90% 80%
K46 6,000 90% 80%
S Series
S15 300 90% 80%
S22 400 90% 80%
S32 2,000 90% 80%
S35 3,000 90% 80%
S38 4,000 90% 80%
S38HS 5,500 90% 80%
S60 10,000 90% 80%
S60HS 18,000 90% 90%
iM Series
iM16K 16,000 90% 90%
iM30K 28,000 90% 90%
Isostatic Crush Strength
True Density (g/cc)
Product Typical Minimum Maximum
K Series
K1 0.125 0.10 0.14
K15 0.15 0.13 0.17
K20 0.20 0.18 0.22
K25 0.25 0.23 0.27
K37 0.37 0.34 0.40
K46 0.46 0.43 0.49
S Series
S15 0.15 0.13 0.17
S22 0.22 0.19 0.25
S32 0.32 0.29 0.35
S35 0.35 0.32 0.38
S38 0.38 0.35 0.41
S38HS 0.38 0.35 0.41
S60 0.60 0.57 0.63
S60HS 0.60 0.57 0.63
iM Series
iM16K 0.46 0.43 0.49
iM30K 0.60 0.57 0.63
True Density
Typical Properties
Not for specification purposes
Typical Properties
Chemical Resistance
In general, the chemical properties of 3M
Glass Bubbles
resemble those of a soda-lime-borosilicate glass.
Thermal Conductivity
Product
Calculated Thermal Conductivity
(W m-1 K-1) at 70 F (21 C)
K Series
K1 0.047
K15 0.055
K20 0.070
K25 0.085
K37 0.124
K46 0.153
S Series
S15 0.055
S22 0.076
S32 0.108
S35 0.117
S38 0.127
S38HS 0.127
S60 0.200
S60HS 0.200
iM Series
iM16K 0.153
iM30K 0.200
Conductivity increases with temperature and product density. The
thermal conductivity of a composite will depend on the matrix
material and volume loading of 3M glass bubbles.
Thermal Stability
Appreciable changes in bubble properties may occur above 1112 F
(600 C) depending on temperature and duration of exposure.
Flotation
Floaters (% by bulk volume)
Product Typical Minimum
K Series
K1 96% 90%
K15 96% 90%
K20 96% 90%
K25 96% 90%
K37 94% 90%
K46 92% 90%
S Series
S15 96% 90%
S22 96% 90%
S32 94% 90%
S35 96% 90%
S38 94% 90%
S38HS 96% 90%
S60 92% 90%
S60HS 92% 90%
iM Series
iM16K 96% 90%
iM30K 92% 90%
Packing Factor (Ratio of bulk density to true particle density)
Averages about 60%.
Oil Absorption
0.2 0.6 g oil/cc of 3M glass bubbles, per ASTM D281-84.
Volatile Content
Maximum of 0.5 percent by weight.
Alkalinity
Maximum of 0.5 milliequivalents per gram
pH
Because 3M glass bubbles are a dry powder, pH is not defined. The pH effect will be determined by the alkalinity as indicated above. When 3M glass bubbles are mixed with deionized water at 5% volume loading, the resulting pH of the slurry is typically 9.1 to 9.9, as measured by a pH meter.
Dielectric Constant
K Series: 1.2 to 1.7 @ 100 MHz, based on theoretical calculations.
S Series: 1.2 to 2.0 @ 100 MHz, based on theoretical calculations.
iM Series: 1.2 to 1.7 @ 100 MHz, based on theoretical
calculations
The dielectric constant of a composite will depend on the matrix
material and volume loading of 3M glass bubbles.
Particle Size
Particle Size (microns, by volume) 3M QCM 193.0
Product Distribution
Effective
Top Size10th% 50th% 90th%
K Series
K1 30 65 115 120
K15 30 60 105 115
K20 30 60 90 105
K25 25 55 90 105
K37 20 45 80 85
K46 15 40 70 80
S Series
S15 25 55 90 95
S22 20 35 65 75
S32 20 40 70 80
S35 20 40 65 80
S38 15 40 75 85
S38HS 19 44 70 85
S60 15 30 55 65
S60HS 12 29 48 60
iM Series
iM16K 12 20 30 40
iM30K 8.6 15.3 23.6 26.7
3M
Glass Bubbles K, S and iM Series
Minimum storage conditions should be unopened cartons in an
unheated warehouse.
Under high humidity conditions with an ambient temperature
cycling over a wide range, moisture can be drawn into the bag
as the temperature drops and the air contracts. The result may
be moisture condensation within the bag. Extended exposure to
these conditions may result in caking of the 3M glass bubbles
to various degrees. To minimize the potential for caking and
prolong the storage life, the following suggestions are made:
1. Carefully re-tie open bags after use.
2. If the polyethylene bag is punctured during shipping or
handling, use this bag as soon as possible, patch the hole,
or insert the contents into an undamaged bag.
3. During humid summer months, store in the driest, coolest
space available.
4. If good storage conditions are unavailable, carry a
minimum inventory, and process on a first in/first
out basis.
Dusting problems that may occur while handling and processing
can be minimized by the following procedures:
1. For eye protection wear chemical safety goggles. For
respiratory system protection wear an appropriate NIOSH/
MSHA approved respirator. (For additional information
about personal protective equipment, refer to Material
Safety Data Sheet.)
2. Use appropriate ventilation in the work area.
3. Pneumatic conveyor systems have been used successfully
to transport 3M glass bubbles without dusting from
shipping containers to batch mixing equipment. Static
eliminators should be used to help prevent static charges.
Diaphragm pumps have been used to successfully convey
3M glass bubbles. Vendors should be consulted for
specific recommendations.
3M glass bubble breakage may occur if the product is improperly
processed. To minimize breakage, avoid high shear processes such
as high speed Cowles Dissolvers, point contact shear such as gear
pumps or 3-roll mills, and processing pressures above the strength
test pressure for each product.
Health and Safety Information
For product Health and Safety Information, refer to product label
and Material Safety Data Sheet (MSDS) before using product.
Particle Size (continued)
Hard Particles (3M QCM 93.4.3)
No hard particles (e.g. glass slag, flow agent, etc.) greater than
U.S. number 40 (420 microns) standard sieve will exist.
Oversize Particles (3M QCM 93.4.4)
For K1, K15, K20 and K25 glass bubbles:
Using a 10 gram sample on a U.S. number 80 standard sieve
(177 microns), a maximum of five (5) percent by weight glass
bubbles will be retained on the sieve.
For K37 and K46 glass bubbles:
Using a 10 gram sample on U.S. number 100 standard sieve
(149 microns), a maximum of one (1) percent by weight glass
bubbles will be retained on the sieve.
For S15, S32, S35, S38, S38HS, S60, S60HS, iM16K and iM30K
glass bubbles:
Using a 10 gram sample on a U.S. number 140 standard sieve
(105 microns), a maximum of three (3) percent by weight glass
bubbles will be retained on the sieve.
For S22 glass bubbles:
Using a 10 gram sample on a U.S. number 200 standard sieve
(74 microns), a maximum of five (5) percent by weight glass
bubbles will be retained on the sieve.
Appearance (3M QCM 22.85)
White to the unaided eye.
Flow (3M QCM 22.83)
3M
Glass Bubbles remain free flowing for at least one year from
the date of shipment if stored in the original, unopened container
in the minimum storage conditions of an unheated warehouse.
Labeling
3M glass bubbles will be packaged in suitable containers to help
prevent damage during normal handling and shipping. Each
container will be labeled with:
1. Name of manufacturer
2. Type of 3M glass bubbles
3. Lot number
4. Quantity in pounds
Storage and Handling
To help ensure ease of storage and handling while maintaining
free flowing properties, 3M
Glass Bubbles have been made
from a chemically stable glass and are packaged in a heavy-duty
polyethylene bag within a cardboard container.
Packaging Information
Small Box (10 Cubic ft.)
A single corrugated box with a plastic liner. All boxes are
banded together and to the wooden pallet. 4 boxes per pallet.
Each box inside diameter is 22 in. 19 in. 39 in.
Pallet size is 42 in. 48 in.
Large Box (50 Cubic ft.)*
A single corrugated box with a plastic liner. Top enclosed
with interlocking double cover banded. Bottom is normal box
closure, entire box banded to wooden pallet.
Each box inside diameter is 48 in. 42 in. 44 in. Overall
load size is 48
3
/4 in. 42
3
/4 in. 50 in. including pallet.
Pallet size is 42 in. 48 in.
*S60 and S60HS large boxes are 38 cubic ft.
Product
Small
Box
Large
Box*
Truckload Large Box*
44 Pallets
K Series
K1 40 lb. 210 lb. 9,240 lb.
K15 50 lb. 265 lb. 11,660 lb.
K20 60 lb. 350 lb. 15,400 lb.
K25 80 lb. 430 lb. 18,920 lb.
K37 100 lb.660 lb. 29,040 lb.
K46 125 lb.815 lb. 35,860 lb.
S Series
S15 50 lb. 265 lb. 11,660 lb.
S22 60 lb. 385 lb. 16,940 lb.
S32 100 lb.525 lb. 23,100 lb.
S35 100 lb.630 lb. 27,720 lb.
S38 100 lb.680 lb. 29,920 lb.
S38HS 100 lb.680 lb. 29,920 lb.
S60 125 lb.850 lb. 37,400 lb.
S60HS 125 lb.850 lb. 37,400 lb.
iM Series
iM16K 99 lb. 800 lb.
iM30K 125 lb.850 lb. 37,400 lb.
Box Weights
*Box weights may vary due to manufacturing tolerances on each product.
Resources
3M
Glass Bubbles are supported by global sales, technical and
customer service resources, with fully-staffed technical service
laboratories in the U.S., Europe, Japan, Latin America and
Southeast Asia. Users benefit from 3M s broad technology base
and continuing attention to product development, performance,
safety and environmental issues.
For additional technical information on 3M glass bubbles in the
United States, call 3M Advanced Materials Division, 800-367-8905 .
For other 3M global offices, and information on additional 3M
products, visit our website at: www.3M.com/engineeredadditives .
3M
Glass Bubbles K, S and iM Series
Please recycle. Printed in USA.
3M 2013. All rights reserved.
Issued: 3/13 9049HB
98-0212-3859-1
3M is a trademark of 3M. Used under license
by 3M subsidiaries and affiliates.
3M Center
St. Paul, MN 55144-1000
1-800-367-8905
www.3M.com/engineeredadditives
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consequential, regardless of the legal theory asserted, including warranty, contract, negligence or strict liability.
Technical Information: Technical information, recommendations, and other statements contained in this document or provided by 3M personnel are based on tests or experience that 3M
believes are reliable, but the accuracy or completeness of such information is not guaranteed. Such information is intended for persons with knowledge and technical skills sufficient to
assess and apply their own informed judgment to the information. No license under any 3M or third party intellectual property rights is granted or implied with this information.