ASTM D4969-97

Standard Specification for Polytetrafluoroethylene-(PTFE) Coated Glass Fabric

SCOPE
1.1 This specification covers glass fabric coated on both sides with PTFE.
1.2 The PTFE-coated glass fabric is for electrical, chemical, and mechanical uses.
1.3 The PTFE-coated glass fabric of this specification does not pertain to structural fabric nor materials used for laminates.
1.4 The values stated in SI units as detailed in Practice E380 and the practices of E380 incorporated herein, are regarded as standard.

General Information

• Status: Historical
• Publication Date: 09-Nov-1997
• ICS: 59.080.40 - Coated fabrics
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.15 - Thermoplastic Materials

Relations

• Replaced By: ASTM D4969-02 - Standard Specification for Polytetrafluoroethylene—(PTFE) Coated Glass Fabric
• Effective Date: 10-Dec-2002

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 4969 – 97
Standard Specification for
Polytetrafluoroethylene–(PTFE) Coated Glass Fabric
This standard is issued under the fixed designation D 4969; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope * Fabric and Glass Fabric Tapes Used for Electrical Insula-
tion
1.1 This specification covers glass fabric impregnated,
D 1424 Test Method for Tearing Strength of Fabrics by
coated, and sintered on both sides with PTFE to a nominal
Falling-Pendulum Type (Elmendorf) Apparatus
thickness of 0.318 mm (0.015 in.) or less.
D 1898 Practice for Sampling of Plastics
1.2 The PTFE-coated glass fabric is for electrical, chemical,
D 3892 Practice for Packaging/Packing of Plastics
and mechanical uses.
D 4441 Specification for Aqueous Dispersions of Polytet-
1.3 The PTFE-coated glass fabric of this specification does
rafluoroethylene
not pertain to structural fabric, single-sided PTFE coatings, or
E 380 Practice for Use of the International System of Units
materials used for laminates.
(SI)
1.4 The values stated in SI units as detailed in Practice
2.2 ISO Standard:
E 380 and the practices of Practice E 380 incorporated herein,
ISO 12086-2: 1995 Plastics—Fluoropolymer Dispersions
are regarded as standard.
and Moulding and Extrusion Materials—Part 2: Prepara-
NOTE 1—There is no ISO standard that covers information included in
tion of Test Specimens and Determination of Properties
this specification. A few of these test methods are mentioned in ISO
12086-2: 1995.
3. Terminology
3.1 Definitions—Definitions of terms relating to plastics
2. Referenced Documents
used in this specification shall be in accordance with Defini-
2.1 ASTM Standards:
tions D 883. Definitions of terms relating to textiles used in this
D 123 Terminology Relating to Textile Materials
specification shall be in accordance with Terminology D 123.
D 149 Test Methods for Dielectric Breakdown Voltage and
3.1.1 structural fabric—PTFE-coated fabric to a thickness
Dielectric Strength of Solid Electrical Insulating Materials
of greater than 0.381 mm (0.015 in.).
at Commercial Power Frequencies
D 257 Test Methods for D-C Resistance or Conductance of
4. Classification
Insulating Materials
4.1 There shall be six types of PTFE-coated glass fabrics as
D 374 Test Methods for Thickness of Solid Electrical Insu-
described in Table 1.
lation
4.2 A one-line system may be used to specify materials
D 578 Specification for Glass Fiber Yarns
covered by this specification. The system uses redefined cells
D 579 Specification for Griege Woven Glass Fabrics
to refer to specific aspects of this specification, as illustrated
D 618 Method for Conditioning Plastics and Electrical In-
below as follows.
sulating Materials for Testing
Specification
D 737 Test Method for Air Permeability of Textile Fabrics
Standard Number Type Grade Class Special
D 751 Test Methods for Coated Fabrics
Block Notes
D 827 Method of Test for Edge Tearing Strength of Paper Example: ASTM D4969-97 IV – – ,
D 883 Definitions of Terms Relating to Plastics
For this example, the line call out would be: ASTM D
D 902 Methods of Testing Flexible Resin-Coated Glass
4969 – 97, IV – – , Porosity 15–30 CFM, and would specify a
Type IV porous product which is referenced in Table 1 with no
grade or class since these subcategories do not appear in this
This specification is under the jurisdiction of Committee D-20 on Plastics and
specification. A comma is used as the separator between the
is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials.
Current edition approved Nov. 10, 1997. Published April 1998. Originally
e1
published as D 4969 – 89. Last previous edition D 4969 – 91a .
2 7
Annual Book of ASTM Standards, Vol 07.01. Annual Book of ASTM Standards, Vol 08.02.
3 8
Annual Book of ASTM Standards, Vol 10.01. Annual Book of ASTM Standards, Vol 08.03.
4 9
Annual Book of ASTM Standards, Vol 08.01. Annual Book of ASTM Standards, Vol 14.02.
5 10
Annual Book of ASTM Standards, Vol 09.02. Available from American National Standards Institute, 11 W. 42nd St., 13th
Discontinued, See 1981 Annual Book of ASTM Standards, Part 20. Floor, New York, NY 10036.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 4969
TABLE 1 PTFE-Coated Glass Fabric Types
Type Name General Description and Common Application
I Premium Smooth, defect-free, primarily used as a dielectric application, release sheet,
and Military Specification material.
II Standard Regular-grade material primarily used for mechanical applications where
temperature and easy-release characteristics are required.
III Mechanical Regular-grade material primarily used for mechanical applications where
smoothness is not a critical requirement.
IV Porous Permeable material, with a range of porosity primarily used as a release sheet in
molding.
V Tear resistant Smooth, flexible, and tear-resistant material for mechanical applications requiring
flexible materials.
VI Conductive Regular-grade material primarily used for static discharge.
standard number and the type. Separators are not needed 6.2.4 Other colors for products that contain pigments, fill-
between the type, grade, and class because they are, in turn, ers, and additives will be agreed upon between the suppliers
Roman numerals, Arabic digits, and uppercase letters, as and the customers.
provided in Section B8 of Form and Style for ASTM Standards. 6.3 Thickness—The thickness of the glass fabric is depen-
Provision for “Special Notes” is included so that other infor- dent on glass style and percent PTFE coating. Tolerances are
mation can be provided when required. An example would be typically 6 10 % of the finished thickness. Thickness shall be
in this specification where porosity would be defined as 15–30 tested in accordance with Test Methods D 374.
CFM. When special notes are used, they should be preceded by
NOTE 2—Typically, glass and coated glass products are manufactured
a comma.
to a weight per unit area.
6.4 Breaking Strength—When tested in accordance with
5. Materials and Manufacture
Methods D 902, the breaking strength shall be at least 80 % of
5.1 Glass Fabric—The base material used in the manufac-
the specified value stated in Table 6 of Specification D 579.
ture of the products of this specification shall be a woven glass
NOTE 3—Reduction of tensile strength is due to added heat required for
fabric produced in accordance with Specification D 579. A
coating.
guideline for generally acceptable substrate fabrics for the
common thickness of PTFE/glass fabric products is given in
6.5 Edge Tear Strength—(Elmendorf) Tears shall be tested
Table 2.
in accordance with Test Method D 1424. Tear values are
5.2 Coating—The glass fabric is impregnated or coated
dependent upon glass style and additives added to the PTFE.
with polytetrafluoroethylene in accordance with Specification
Typical Tear Resistant (Type 5) products exhibit two times the
D 4441. Additives may be added to the dispersion to achieve
values of their counterparts. Conductive (Type 6) products
the required properties and performance of the final product.
exhibit one half the values of their counterparts. Test values
and tolerances shall be determined by the supplier and the
6. Physical Requirements
customer.
6.1 The coating shall penetrate and adhere to the fabric and 6.6 Mass—A sample shall be prepared in accordance with
shall be substantially free of wrinkles, creases, blisters, and Method D 751. The amount of PTFE added shall be agreed
other imperfections. upon between the customer and the supplier and shall have a
6.2 Color: tolerance of 65 % of the total coated product weight.
6.2.1 The material will have a natural color that varies from 6.7 Widths—The coated glass fabric shall be furnished in
off-white to dark brown when viewed by the unaided eye. The the widths and tolerances indicated in Table 3, when tested in
usual color is tan. accordance with Method D 751.
6.2.2 Color should be specified only if it is a critical 6.8 Conductivity—For Type 6 material, conductivity shall
parameter to the customer.
be tested in accordance with Test Methods D 257, using the
6.2.3 Color should be uniform from roll to roll within a lot. Flat Metal Plate Method, and a comparison bridge. Material
shall be deemed conductive when the resistivity is below 10
V/square.
TABLE 2 Accepta
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