SODIUM SILICATE
FORMED SHAPES
SCHUNDLER

PIPE AND BOARD
INSULATION
PRODUCT GUIDE
The Schundler Company
150 Whitman Avenue
Edison, New Jersey 08817
732-287-2244 www.schundler.com



PERLITE/SILICATE COMPOSITES FOR
HIGH TEMPERATURE INSULATION AND FORMED SHAPES


WHAT IS PERLITE

Perlite is not a trade name but a generic term for naturally occurring siliceous volcanic rock. The distinguishing feature which sets perlite apart from other volcanic glasses is that when heated to a suitable point in its softening range, it expands four to twenty times its original volume.

This expansion is due to the presence of two to six percent combined water in the crude perlite rock. When quickly heated to above 1600 F (8700 C) the crude rock pops in a manner similar to popcorn as the combined water vaporizes and creates countless tiny bubbles in the heat softened glassy particles. It is these tiny glass-sealed bubbles which account for the excellent insulating properties and lightweight of expanded perlite.

Expanded perlite can be manufactured to weigh from 2 lb/ft3 (32 kg/m3) to 15 lb/ft3 (240 kg/m3) making it especially suitable for use in insulation applications. Perlite is used in the manufacture of lightweight perlite concrete, insulating board, insulating plasters, cryogenic insulation, masonry wall insulation and as underfloor insulation.


Both flat and rounded forms of socium silicate perlite insulation


PERLITE/SILICATE COMPOSITES

Expanded perlite granules can be bonded to form rigid shapes for a very wide range of applications. The most suitable binder for many purposes is a liquid sodium silicate similar to traditional "waterglass." The liquid sodium silicates are solutions of water soluable glasses manufactured from varied proportions of Na2C03 and SiO2, providing a wide range of chemical and physical properties.

Sodium silicates are widely used as high temperature adhesives and binders due to the following properties:

Silicate-bonded perlite makes an insulation material which is completely non-flammable, the refractory nature of the bond being a major advantage.

Potassium silicate is sometimes preferred for applications where heat insulation and fire resistance are the main objectives. This material has a slightly higher softening point than its sodium counterpart.

Sodium silicate is widely used as a binder for molding sand in foundries. The technology for perlite/sodium silicate composite manufacture is based largely on this foundry industry experience.


TYPICAL PROPERTIES OF
PERLITE/SODIUM SILICATE COMPOSITES
Thermal Conductivity (ASTM C-177, C-325)
.... at mean temp. 2500F (1200C)
0.40 BTU.in/h.ft2.F0
(0.058 W/m.K)
Thermal Conductivity (ASTM C-177, C-325)
.... at mean temp. 4500F (2300C)
0.56 BTU.in/h.ft2.F0
(0.081 W/m.K)
Thermal Conductivity (ASTM C-177, C-325)
.... at mean temp. 6600F (3500C)
0.65 BTU.in/h.ft2.F0
(0.094 W/m.K)
Thermal Limit (ASTM C-447)12000F (6500C)
Density(ASTM C-447)11-16 lb/ft3 (180-260 kg/m3)
Modulus of Rupture (ASTM C-203,C-446)
.....minimum
50-60 lbs/in2 (0.34-0.41 N/mm2
Compressive Strength(ASTM C-165)
.....minimum
75-88 lbs/in2 (0.52-0.61 N/mm2
Linear Shrinkage (ASTM C-356)less than 2% at 1200 0
Water Absorptonunder 10% by volume after 24 hours

PERLITE/SODIUM SILICATE TECHNOLOGY

A wide range of formulations of perlite, sodium silicate solution and setting agent can be used, together with additives to control setting of the mix. General guidelines are given as a starting point.

SOLUBLE SILICATE GRADES

The choice of grade of sodium silicate solution depends on the application and setting process being used. Generally, a higher silicate to alkali ratio gives faster setting while lower ratios and higher solids contents give greater strength in the finished product.

SETTING AGENTS



Setting ProcessSilica/Alkali RationSolids Content %
Gas Injection2.00--2.50:143-50
Liquid Hardeners2.50--2.90:140-45
Solid Hardeners2.00--2.30:145-50

SUGGESTED FORMULATIONS
USING DIFFERENT SETTING AGENTS
Material*Gas SettingLiquid SettingSolid Setting
Sodium silicate solution
as % by volume of perlite
2.5-5%5-10%5-15%
Setting agent as % by weight
of sodium silicate
15-25%
at 680F (200C)
8-14%25-50%
(*amount of silicate needed will depend on the particle size,
density, and absorbency of the perlite used.)



APPLICATIONS OF PERLITE/SILICATE COMPOSITES
High Temperature InsulationFire ProctionBuilding ConstructionOther Applications
Pipe covering
Furnace lining
Industrial ovens/kilns
Domestic oven lining
Firebncks and stoves
Chimney insulation
Foundry molds and coves
Runner insulation shapes
Refractory shapes
Fire doors
Fire resistant coatings
Steelwork cladding
Roof truss insulation
Fire-safe cabinets
Document boxes
Computer disk storage
Electrical control boxes
Ceiling tiles
Accoustical panels
Sandwich panels
Wall insulation blocks
Cryogemc tank base insulation
Decorative moldings and shapes
Sprayed coatings
Acid resistant blocks
Roofing tiles
Liquid waste solidification
Asbestos encapsulation
Oil absorbents
Welding rod coatings



The Schundler Company doesn't manufacture sodium silicate composites. For specific information about these products, contact:

Or, please call or contact us at:

The Schundler Company
150 Whitman Avenue
Edison, New Jersey 08817
(ph)732-287-2244 (fax) 732-287-4185
www.schundler.com
email: info@schundler.com

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