1.Glass Fabric Properties
Woven fiber glass fabrics offer the widest range and the best control over thickness, weight and strength of all forms of fiberglass textiles. This offers the materials engineer a wide choice of controlled fabric properties to satisfy design needs and objectives. In general, woven glass fabrics have the following properties:
High Tensile Strength:
Glass is one of the strongest textile fibers, having greater specific tensile strength than steel wire of the same diameter, at a lower weight.
Dimensional Stability:
Low elongation under load, generally 3% or less. Glass fibers produce fabrics with excellent dimensional stability under various types of conditions.
High Heat Resistance:
Glass fabrics have excellent heat resistance at relatively low cost. They retain approximately 50% of room temperature tensile strength at 700F (371C); approximately 25% at 900F (482C); with a softening point of 1555F (846C) and a melting point of 2075F (1121C).
Fire Resistance:
Composed of inorganic materials, glass fabrics are noncombustible, a natural choice where flammability is of concern.
Good Thermal Conductivity:
The rapid heat dissipation of glass fabrics is particularly important in electrical insulation applications.
Good Chemical Resistance:
Like glass itself, fiber glass fabrics are highly resistant to attack by most chemicals.
Outstanding Electrical Properties:
Glass fabrics withstand high temperature and have low moisture regain. Along with its high dielectric strength and low dielectric constant, glass is of major importance and usefulness in the electrical industry.
Durability:
Being inert, glass fabrics are unaffected by sunlight, fungus or bacteria.
Economical:
Glass fabrics are lower in cost than many other fabrics for similar applications.
2.Glass Yarn Nomenclature
US Glass System - Example: ECG 150 3/2 3.0S
The example above, identifies the following yarn:
E = electrical glass
C = continuous filament
G = average filament diameter of 0.00037"(9 Micron)
150 = 15,000 yards/lb. nominal bare glass in basic strand.
3/2 = two plies of 3-strand construction (total 6 basic strands)
3.0S = the number of turns per inch in the twist of the final yarn in the S direction
3.Glass Composition
(By Weight)
E-Glass S-Glass
Silicone Dioxide 52 - 56% 64 - 66%
Calcium Oxide 16 - 25% 0 - .3%
Aluminum Oxide 12 - 16% 24- 26%
Boron Oxide 5 -10%
Sodium Oxide & Potassium Oxide 0 - 2% 0 - .3%
Magnesium Oxide 0 - 5% 9 - 11%
Iron Oxide . 0.5 - .4% 0 - .3%
Titanium Oxide 0 - .8%
Fluorides 0 -1.0%
4.Glass Filament Diameter
Fiber Designation Nominal Filament Diameter Nominal Filament Diameter
Glass-Cut (Microns) (Inches)
B 3.5 0.00012
C 4.5 0.00018
D 5 0.00021
DE 6 0.000256
E 7 0.00028
G 9 0.00037
H 10 0.00043
K 13 0.00051
5.Fabric Selection Design Parameters
Selection of a glass fabric for industrial use is not as simple as selecting a fabric for home or office decoration where style and color may be the principal considerations.
There are six basic design variables to be considered:
Thickness:
Glass fabrics are available in thicknesses ranging from .0010" to .050" (0.0254-1.27mm).
Weight:
Weight range extends from less than one ounce per square yard to over 54 ounces per square yard (19-1856 g/m2).
Construction:
This is the number of warp yarns (in the machine direction) and filling yarns (cross-machine direction) per inch of the fabric.
Yarn Size:
A wide variety of yarn sizes are available which determine the weight and thickness of the fabric. For specific purposes, one yarn may be selected over another to give certain performance characteristics to the fabric.
Finish:
Most industrial applications require glass fabric to be used in conjunction with another material. For compatibility with the other materials, a finish or after treatment is frequently applied to the fabric. Desc riptions of the various finishes appear in each of the corresponding product sections.
Weave Pattern
Plain
A plain weave is the most simple and most commonly used weave pattern. In this type of weave, the warp and filling threads cross alternately. Plain woven fabrics are generally the least pliable, but they are also the most stable.
Leno
The leno weave is a locking type weave in which two or more warp threads cross over each other and interlace with one or more filling threads. It is used primarily to prevent shifting of fibers in open weave fabrics.
Satin Weave
In a satin weave, the face of the fabric consists almost completely of warp or filling floats produced in the repeat of the weave, which causes one side of the fabric to look different than the other side. There is one filling thread which floats over three or more warp threads, then under one. This is the most drapeable of weave patterns and conforms very easily around most contoured surfaces. Most satin weaves are either four, five, eight, or twelve harness satins and are typically utilized in the composites industry.
Twill
A twill weave is a basic weave characterized by a diagonal rib, or twill line. Each end floats over at least two or more consecutive picks enabling a greater number of yarns per unit area than a plain weave, while not losing a great deal of fabric stability. This type of fabric looks different on one side than on the other.
Basket Weave
The basket weave is a variation of the plain weave in which two or more warp yarns cross alternately with two or more filling yarns, resembling a plaited basket. This weave is more pliable and stronger than a plain weave, but is looser and therefore, not as stable. The basket weave is typically used in the composites industry.
6.Technical Reference > Determining Roll Diameter
Determining Roll Diameter
The following is an approximate formula for determining the diameter of a roll of fabric. The formula generally underestimates roll diameter for fabrics with texture or some specialty yarns. Also, actual diameters can vary at different take-up tensions.
TX144XY+C2
-------------------
¶
Where, T = thickness of fabric (inches)
Y = linear yards of fabric
C = core diameter (OD)
7.Style Alterations Chart
The following chart gives the general direction of changes in certain fabric characteristics, when the construction is altered. These relationships may not always apply, however, the magnitude of the change would be negligible.
What Happens To:
If You Cost Thickness Weight Strength Porosity
Increase the No. of Picks + + + + -
Increase the No. of Ends + + + + -
Increase Yarn Size (filament size or No.) + + + + -
Change from Filament to Textured + + + - +
Increase No. of Plies
(e.g. 75 1/0 to 150 1/2) + 0 0,+ 0,+ +
Change from E to S glass + + 0 + 0
+ = increase, - = decrease, 0 = no change
Weave Rankings Cost Thickness Weight Strength Porosity
Plain 1 3 1 3 1
Twill 1 2 1 4 2
4-Harness Satin (Crowfoot) 1 3 1 4 2
8-Harness Satin 1 1 1 7 4
Leno 7 7 7 1 7
Mock Leno 1 6 1 2 4
1 = lowest cost, 1 = least thick, 1 = lightest, 1 = weakest, 1 = closed
7 = highest cost, 7 = thickest, 7 = heaviest, 7 = strongest, 7 = open
8.Fiber Glass Fabric Finishes
Many fiber glass fabrics will require finishing which is determined by the particular application or end use of the fabric. Fabrics which are not finished are called greige, loom state, or untreated fabrics.
Finishing processes include but are not limited to:
Removal of the sizing and binder that was applied to the glass fibers to facilitate weaving. This is accomplished through heat cleaning, scouring, or other specialized methods. After cleaning, the fabric may be treated with chemical agents which interact with the chemistry and processes used by our customers or may be left as is.
Sizing and binder may be left on the fabric with various chemical agents applied directly over the greige/loom state fabric.
Standard Finishes:
208 Comparable to 603A but pigmented red to indicate non-asbestos material.
A218 Special processing for surfboard fabric which improves wetout, clarity, and laminate
strength.
231 PVC Weaveset - medium add-on
236 PVC Weaveset - high add-on
252 Acrylic Weaveset - medium add-on
261 Patented flame-retardant, low toxic, low smoke, white paint-like finish for navy board
and acoustical fabrics.
263 Acrylic Weaveset - with good slitability - high add-on
263F Firm version of 263
271 PVAC acrylic copolymer white weaveset used mainly in roofing
272 Same as 271 but black
273 Same as 271 but yellow
274 A firm low add-on acrylic weaveset with low smoke flame retardant properties.
318 Low toxic, low smoking, high reflective, pre-painted white ceiling board finish. Colors
available as 318x finishes.
373 Chemical resistance consisting of polymer/PTFE
422 White PVC/Acrylic weaveset for laminated window shades.
445 Alkali resistant finish for cement reinforcement
460 Finish compatible with epoxy and phenolic resins
497A A silane finish that can undergo addition or condensation reactions with polymeric
resins. Is compatible with epoxy, phenolic, polyimide, and polyester resins.
501 Thermal cleaning finish, designed for silicone laminates (formerly called 112), used
with styles 104 and 106. Fabric is normally white in color.
504 Volan Chrome complex finish compatible with polyester and epoxy resins.
508A Finish compatible with epoxy, phenolic, and polyimide resins
514 Neutral pH, recommended for silicone laminates.
516 Silane finish over thermal cleaned fabric for melamine laminates.
517 Continuous heat cleaning finish (formerly 210). Fabric is normally tan in color.
538 Soft A-1100 silane finish compatible with epoxy, phenolic, and polyimide resins.
550 Combination of Volan and silane coupling agents compatible with polyester and epoxy
resins.
558 A finish based on Z-6040 silane compatible with epoxy resins.
537 Thermal cleaning finish, designed for silicone laminates, used with styles other than
104 and 106. Fabric is normally white in color.
580 Triple finish consisting of silicone oils/graphite/PTFE
581 Weaveset for paintable ceiling board fabric.
602 Modified silane finish for superior wet-out specialty resin applications. Good for
polybutadiene
603A Multi-purpose pad covering and lagging finish, providing good hand, minimal dust,
and ease of application.
610A Pre-applied rewettable lagging finish that is water activated and provides ease of
application.
615 10% add-on of DuPont's Teflon® B
618 Scouring process for removal of extractable material (to less than 0.1%), maximizing
resin compatibility.
621 High performance finish for epoxy and polyimide resins
625 Acid resistance consisting of acid resistant polymers/PTFE/silicone oils, graphite
627 A silane finish compatible with polyester and vinyl ester resins.
629 Lower add-on of 318
633 Water resistant finish.
636 High impact, soft formable finish for polyester resins
642 Good moisture resistance and electrical properties with good wet-out. Developed for
FR-4 epoxy but also recommended for polyimide, BT, and Cyanate Ester.
643 Developed for multilayer and bonding sheets applications but also good for general
epoxy FR-4 applications. Exhibits very good wet-out characteristics.
646 Low chloride silane finish for multilayer and bonding sheets applications. Also general
epoxy FR-4 applications. Exhibits very good wet-out and moisture resistance.
644 Modified Z-6040 silane finish for epoxy resins.
832V A light add-on soft acrylic weaveset to improve fabric processing in laminating.
832W A medium add-on soft acrylic weaveset to improve fabric processing in laminating.
818P Polyester weaveset, high add-on
971C Flame retardant coating for smoke curtains.
975 PVA weaveset which reduces fabric porosity and aids slitting and sewing.
983 High temperature ceramic coating.
9.Specifications
The following specifications are referenced herein:
AMS 3824: This specification covers E-glass in the form of woven cloth primarily as a reinforcing material for structural plastic laminates with finishes suitable for use with various resin matrices.
AMS 3902: This specification covers cloth woven from high modulus, continuous, multifilament aramid yarn.
ASTM E-84 "TUNNEL TEST", CLASS A: Test method for surface burning characteristics of building materials.
ASTM C 1086-88: This is the standard specification for glass fiber felt thermal insulation.
BMS 8-274: This specification covers the requirements for fire retardant, modified phenolic resin impregnated graphite panels. They are intended for use in the fabrication of aircraft interior sandwich panels.
BMS 9-3: This specification covers the requirements for woven glass fabric reinforcements used by The Boeing Company and Boeing subcontractors, and supplied to The Boeing Company and Boeing subcontractors by raw material suppliers for structural and nonstructural laminated products. This specification requires qualified products.
BMS 9-8: This specification establishes requirements for woven and non woven graphite reinforcement.
GE A50TF 213 S7: This specification establishes requirements for epoxy resin impregnated carbon fabrics primarily for use in lightweight composites. Cured laminates exhibit good mechanical properties up to 180F (80C) and intermittently to 220F (105C).
GE A50TF 216: This specification establishes requirements for epoxy resin, impregnated carbon fabrics primarily for use in lightweight composites. Cured laminates exhibit good mechanical properties up to200F (93C).
GE A50TF 226 S7: This specification describes requirements for woven carbon fabric.
GE A50TF 236: This specification establishes requirements for epoxy resin, impregnated carbon fabrics primarily for use in lightweight composites. Cured laminates exhibit good mechanical properties up to260F (127C).
GE A50TF 294 S2: This specification establishes requirements for (PMR-15) polyimide resin impregnated carbon fabric. This material is intended for primary structural laminates requiring high strength atelevated temperatures.
IPC EG-140: Specification for finished fabrics woven from "E" glass for printed circuit boards.
LOCKHEED FMS-3015A: This specification establishes the minimum requirements for woven glass cloth that has been suitably finished for fabrication into an epoxy laminate.
LOCKHEED FMS-3015B: This specification establishes the minimum requirements for woven glass cloth that has been suitably finished for fabrication into an epoxy laminate.
LOCKHEED 5PTMGG15: This specification establishes the requirements for miscellaneous styles of glass fabric, glass yarn, and glass woven tapes.
MIL-C-9084: This specification covers the requirements for glass fabrics that have been woven, cleaned, and finished for further fabrication into the glass fabric base resin laminates and sandwich materials.
MIL-C-20079: Specification covers glass textiles: cloth, tapes, and threads.
MIL-1-24244: This specification covers asbestos free thermal insulation with special corrosion, chloride, and fluoride requirements.
MIL-1-16411: This specification establishes requirements for fiber glass insulation felt for thermal insulation of machinery and equipment.
MIL-Y-1140: This specification covers the basic forms of untreated glass fiber used by themselves or as components of other materials. The materials are generally used as electrical insulation, mechanical support or as structural members.
U.L.®, ref. #R11184: This is the Underwriters Laboratory approval number for BGF Mat.
USG - 164.009: US Coast Guard Dept. of Transportation specification for noncombustible materials for merchant vessels.
