Absorption

Hushcloth acoustical foams are designed to provide maximum absorption of airborne sound with minimum thickness and weight. These flexible polyurethane open cell foam products are manufactured to optimize pore size, air flow resistance, and density.

Sound energy, passing through the cell structure, is converted into minute quantities of low grade heat that is easily dissipated. Since the uniformity of the cells are carefully controlled the efficiency is constant and predictable from one installation to another.

Many applications require these products to be subjected to environments such as dirt, moisture, chemicals, and abrasion that could be hostile to an unprotected foam. These products go through various surface treatments to protect the integrity of the foam from these elements. These facings will increase the absorption properties of certain frequencies as well as provide a cleanable, decorative and durable finish for a wide variety of applications.

Acoustical kits are often the most cost effective way to deal with noise in an OEM application. These parts are ready to install and usually have an aggressive pressure sensitive adhesive (PSA) for fast and permanent bonding. This particular part goes inside a blower housing and has a perforated outline. This allows the assembly personnel to remove a section easily when an optional bracket is installed.

Hushcloth Foams can be purchased in rolls or sheets.  They are easily cut with a knife, saw or scissors.  The addition of pressure sensitive adhesive provides a convenient method of fastening to most substrates.

Hushcloth products can be made in combination with Whispermat^TM barrier systems when both absorption and transmission loss is needed, or VE^TM damping systems, when enhanced vibration control is required.

Polyester Physical Properties:

• Color Charcoal Gray
• Density 2lb/cft or 4lb/cft +/- 10% 32 kg/m3 or 64 kg/m3 +/- 10% per ASTM D3574-86 test A
• Tear Strength 1.5 ppi per ASTM D3574-86 test F
• Tensile Strength 20 psi per ASTM D3574-86 test E
• Elongation 120% per ASTM D3574-86 test E
• Compression Set % 50% Deflection Max 10% ASTM D357-86 test D
• Heat Resistance retention of tensile strength after 22 hours dry heat aging at 140oC min. 70% ASTM D3574-86 test K
• Humidity Resistance retention of tensile strength after 6 hours steam autoclave at 105oC min. 70% ASTM D3574-86 test J
• Chemical Resistance good for common fluids, water, petroleum, solvents, and alkalis. Swelling will occur, will return to almost 100% after drying.
• Flammability MVSS 302, UL-94 HF1, and FAR 25.853(b)
• Service Temperature -40oF to +225oF continuous to 275oF intermittent
• Thermal Conductivity BTU/hr., Ft2, oF/in. .25 per ASTM C 177

Standard Surface Treatments:

• Aluminized Polyester
• Reinforced Aluminized Polyester
• Urethane Films (matte or impervious)
• Tedlar® (trademark E.I. Dupont Co.)
• Perforated Vinyl
• Convoluted
• Embossed
• Customized Facings Available

Pressure Sensitive Adhesive:

• Supported SBR (temps to 140oF)
• Unsupported Acrylic (temps to 250oF)
• Supported Acrylic (temps to 250oF)

Standard Sizes:

• Rolls 54" x 50'
• Sheets 54" x 72", 54" x 24", 54" x 36"
• Fabricated or Die Cut
• Thicknesses 1/4" - 2"

Polyether Physical Properties:

• Color Charcoal Gray
• Density 2lb/cft or 4lb/cft +/- 10% 32 kg/m3 or 64 kg/m3 +/- 10% per ASTM D3574-86 test A
• Tear Strength 1.58 ppi per ASTM D3574-86 test F
• Tensile Strength 13 psi per ASTM D3574-86 test E
• Elongation 193% per ASTM D3574-86 test E
• Compression Set % 50% Deflection Max 10% ASTM D35748-86 test D
• Heat Resistance retention of tensile strength after 22 hours dry heat aging at 140oC min. 70% ASTM D3574-86 test K
• Humidity Resistance retention of tensile strength after 5 hours steam autoclave at 120oC min. 70% ASTM D3574-86 test J
• Chemical Resistance good for common fluids, water, petroleum, solvents, and alkalis. Swelling will occur, will return to almost 100% after drying.
• Flammability MVSS 302, UL-94 HF1, and FAR 25.853(b)
• Service Temperature -40oF to +225oF continuous to 275oF intermittent
• Thermal Conductivity BTU/hr., Ft2, oF/in. .25 per ASTM C 177

Acoustical foam is the most versatile of all noise control materials. dB Engineering has the right foam for your application.

Provides a tough, puncture resistant textured surface making it suitable for use in machine enclosures.

Metalized mylar foam is excellent for use around liquids. The reflective, wipe-clean surface protects against oils, water and many chemicals. Reduces head transfer.

EMBOSSED FOAM

Embossed faced foam is a high performance acoustical material with superior absorption at the most critical frequency bands. It is often used in speaker housings, medical equipment, HVAC units, blower enclosures, and office equipment such as computer and printer housings. The embossed surface has an attractive, high tech appearance that is pleasant to the touch. It readily stands up to abusive air streams and the associated abrasion in air ducts and blower housings. Embossed foam increases sound absorption performance in the most critical frequency bands by 25% to 35% when compared to other available foams. [Click for larger photo.]

FOAM DAMPING SHEET - EMBOSSED
Sound Absorption plus Vibration Damping

The need to absorb noise inside a machine enclosure often accompanies the need to damp vibration on the same structure.   Where it is not possible to totally enclose a noise source, as in many types of machinery, electrical appliances, office equipment and electronic controls, the inside of the enclosure should be lined with sound absorption material.  This provides a non-reflective surface that absorbs air noise generated by gears, linkages, fan blades and rotors.  To reduce vibration noise generated by the same enclosure, particularly if it is of sheet metal, damping is necessary.

Adhesive release paper, .050 inch thick damping, embossed foam, composite shown upside down for viewing purposes (Click to enlarge)

Embossed Foam Damping Sheet consists of a thickness of embossed foam bonded to a thin sheet of high-efficiency damping compound.  In this configuration, Embossed Foam Damping Sheet has proved to be a most satisfactory single solution to this twofold problem.

Available with or without high-quality, pressure-sensitive adhesive backing, it is easy to apply and has a neat appearance.

All thicknesses - 1/4", 1/2", 3/4", and 1" are effective for absorbing high-noise frequencies.   When lower frequencies are dominant, however, thicker foams and fewer openings in the enclosure are required.  Absorption values and damping rates are shown below.

Table 1

Table 2

How to Apply

Damping surface must be clean, free of dirt, oil or grease.  It can be applied to a clean painted surface.  Sometimes, on very smooth surfaces etching or roughing the surface may be required.  Sheet is cut to size with knife, shears or steel rule die.   If sheet is adhesive backed, strip away the protective paper, use roller to apply adhesive side to surface.

The surface treated need not be covered 100% to achieve high damping effectiveness.   A 2/3 area coverage provides at least 80% of the total damping expected.

PERFORATED VINYL FACED FOAMS

Perforated Vinyl Faced Foams combine the absorption properties of acoustical foams with the toughness and durability of vinyl.  The perforation pattern has been engineered to provide maximum absorption and resilience with 14% open area.  The attractive leather like appearance makes it ideal for vehicle interiors, marine headliners, and enclosures. Click to enlarge.)

Standard Sizes:
Rolls: 54" x 150'
Sheets: 54" x 24", 54" x 36", 54" x 72"
Standard Thickness: 1/2", 1", 2"
Standard Colors: Black, 383 Military Green, Sandpiper, White, Mojave Brown, Storm Gray, Embassy Gray

FOAM MELAMINE

Foam Melamine is a lightweight, high temperature resistant, open cell foam manufactured from melamine resin.  It combines excellent thermal properties with superior sound absorption capabilities to create a versatile fiber free product which can be applied in situations which may prohibit the use of urethane foams or fiberglass insulations.  [Click for larger photo.]

This fire retardant foam meets the flame spread, smoke density and fuelcontribution requirements necessary to comply with Class-1 building code regulations.  The high performance thermal and acoustical characteristics of this flexible, low density foam make it an ideal product for in-plant and FDA approved applications.  In addition to being the solution to aircraft and architectural noise problems,Melanine Foam is the material in use in OEM products requiring a combination of thermal and acoustical insulation capabilities.  Optional facings can be applied for more durability and chemical resistance as well as pressure sensitive adhesive for ease of installation.

Physical Properties:
Color: White
Density: .7 lb/ft³ ASTM D3574-86 test A
Tear Strength: .5 ppi per ASTM D3574-86 test F
Tensile Strength: 18 psi per ASTM D3574-86 test E
Elongation: 15% per ASTM D3574-86 test E

Thermal Conductivity: BTU/hr., Ft²., ^oF/in.; .25 per ASTM C 177
Temperature: -45^o F - 302^o F Continuous; to 400^o F Intermittent

Standard Sizes:
Sheets: 24" x 48", 48" x 48", 48" x 96"
Standard Thickness: 1/4" to 18"

All our foam products do not drip upon ignition, cease to burn after removal of the source of ignition and produce a minimal amount of smoke.

IMPORTANT: When the foam is subjected to dirt, grease, moisture and chemical attack, it may require a foam with a protective surface treatment such as our Metalized Mylar or Matte Film Finish foams above.

Most of our products meet all the requirements of UL-94, MVSS-302 and FAR 25.83b. Call or e-mail to request expanded specifications and technical data sheets.

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