A "Soft Gasket" material is a term used when referring to a gasket material that is easily compressed under a low bolt load. This term has been used to distinguish the difference from a metallic gasket. A soft gasket material can be selected from a large variety of rubbers and compressed non-asbestos sheet products. As part of Lamons strategy to offer customers a wider range of products, we are pleased to supply the following soft gasket materials:

•   Elastomeric and Fiber Sheet
•   Compressed Non-Asbestos Sheet
•   Matrix Biaxially Orientated PTFE Sheet
•   Matrix L120  Expanded PTFE Sheet
•   Matrix L120 PTFE Joint Sealant
•   PTFE Envelope Gaskets
•   Virgin / Glass-Filled / Reprocessed PTFE Sheet
•   Flexible Graphite Sheet
•   Mica Sheet
•   Ceramic Fiber

Elastomers

An Elastomer is a polymer with the physical property of elasticity. Elastomer is a term derived from elastic polymer, which is often used interchangeably with the term rubber. Each of the monomers which link to form the polymer is usually made of carbon, hydrogen, oxygen and/ or silicon. Elastomers are usually thermosets requiring a curing process involving heat and the addition of sulfur or other equivalent curatives. In addition, elastomers might also be thermoplastic.

  • SBR (Styrene- Butadiene)
  • CR-Chloroprene (Neoprene)
  • Buna-N/Rubber (Nitrile, NBR)
  • EPDM (Ethylene Propylene)
  • Fluorocarbon (Viton®)
  • Chlorosulfonated Polyethylene (Hypalon®)
  • Natural Rubber
  • Silicones
  • Vegetable Fiber Sheet

Note: Viton® and Hypalon® are registered trademarks of DuPont.

Compressed Non-Asbestos

Early efforts to replace asbestos resulted in the introduction and testing of compressed non-asbestos products in the 1970’s. Many of these products have seen extensive use since that period, however, there have been enough problems to warrant careful consideration in choosing a replacement material for compressed asbestos. Most manufacturers of non-asbestos sheet materials use synthetic fibers, like aramid or Kevlar®, in conjunction with an elastomeric binder. The elastomeric binder makes up a larger percentage of this sheet and thereby becomes a more important consideration when determining applications.

Note: Kevlar® is a registered trademark of DuPont.

L420 is a general-purpose sheet jointing material with good mechanical properties. Constructed with aramid/ organic fiber and a high-quality nitrile rubber binder.

L430 is a general-purpose sheet jointing material with superior mechanical properties. Constructed with premium aramid fiber and a high-quality nitrile rubber binder.

L433 is a premium sheet gasket material with a reinforcement structure consisting of glass and aramid fibers, it is bound together with a high-quality nitrile rubber binder. L433 has excellent resistance to steam due to the addition of glass fiber.

L440 is a good quality sheet gasket material with a wide range of application potential. Manufactured with a formulation of high-quality fillers, premium aramid fibers and a nitrile rubber binder, L440 is a cost effective, high performance gasket material.

L441 is a general service sheet gasket material with a wide range of application potential. Manufactured with a formulation of high-quality fillers, premium aramid fibers and nitrile binder, L441 is the workhorse of the Lamons gasket line.

L443 is a premium sheet gasket material with a reinforcement structure consisting of glass and aramid fibers, it is bound together with a high-quality nitrile rubber binder. L443 has excellent resistance to steam due to the addition of glass fiber.

L450 is a premium sheet gasket material utilizing carbon and aramid fibers, it is bound together with a high-quality nitrile rubber binder. L450 is designed to perform at high temperatures and pressures. Standardization and consolidation of many other gasket materials can be achieved using L450.

L460 is a premium sheet gasket material utilizing graphite and aramid fibers, it is bound together with a high-quality nitrile rubber binder. L460 is designed to perform at high temperatures and pressures. Standardization and consolidation of many other gasket materials can be achieved using L460.

L540 is a compressed sheet gasket material utilizing a high-quality Neoprene binder. It is reinforced with aramid and inorganic fibers. This material has an inherent resistance to oil and petroleum-based solvents.

L640W is a premium compressed sheet gasket material utilizing a high quality SBR binder. It is reinforced with an engineered blend of aramid and inorganic fibers.

L740 is a premium compressed sheet gasket material utilizing a high-quality EPDM binder. It is reinforced with an engineered blend of aramid and inorganic fibers.

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Matrix Biaxially Orientated PTFE Sheet

Matrix is a premium range of PTFE material that covers the full spectrum of customer requirements. This product line covers, biaxially orientated filled materials (L100, L104, L110) for low creep, higher loaded applications. High compression (L120) for applications where high load values are not achievable but low creep is still required.

Matrix L100, L104 and L110 products are manufactured to the HS10 method which was developed by DuPont in 1960. The result is a material that has exceptional strength and stability under load. The resultant biaxial orientation of the PTFE particles creates a unique strength where both the longitudinal and transverse directions are equally as strong. This superior matrix orientation and addition of premium fillers allows the material to resist creep and cold flow when subject to load.

Matrix L120 is our range of high-quality Expanded PTFE (ePTFE), it is offered in both sheet cut gaskets and joint sealant form. L120is manufactured by heating solid Polytetrafluoroethylene, the material is then stretched up to 800% of its original size and this forms a microporous structure which consists of around 70% air. This gives the material good compression characteristics, which allows the ePTFE to seal under low loads. The Matrix range can be used in its pure form or can be used as facings or fillers for our range of semi-metallic gaskets. All our Matrix materials conform to FDA requirements.

PTFE Joint Sealant Matrix L120 is 100% pure, specially processed PTFE sealant provides soft, highly compressible gasketing on a roll for long-life, trouble-free sealing that cuts maintenance and storing costs. Under pressure, PTFE sealant provides a very thin and wide ribbon-like joint sealant so that the smallest possible gasket surface area is exposed to the harmful effects of corrosive media.

L100 A biaxially orientated high-quality silica-filled PTFE sheet for use in sealing most chemicals except molten alkali metals, fluorine gas, and hydrogen fluoride. This material is approved for potable water service, complies with requirements of FDA regulations and can be used at all concentrations of sulfuric acid.

L104 A superior performance, biaxially orientated sheet material containing PTFE and hollow glass microspheres for use in sealing most chemicals except molten alkali metals, fluorine gas and hydrogen fluoride. This material is approved for potable water service, complies with requirements of FDA regulations and has exceptional compression characteristics making it good for use in glass lined flanges or where loading problems exist.

L110 A pigment-free biaxially orientated with superior performance, barium sulfate-filled PTFE sheet for use in sealing food, pharmaceuticals, and other general chemical media. This material complies with requirements of FDA regulations and is acceptable for use in aqueous hydrofluoric acid below 49% but is not suitable for sealing molten alkali metals or fluorine gas.

PTFE Envelope Gaskets

Envelope gaskets utilizing PTFE jackets have become popular for use in severely corrosive services because of their low minimum seating stresses, excellent creep resistance, high deformability and choice of a variety of filler materials to assure optimum performance on any specific application. Fillers such as corrugated metal and rubber sheets are available.

Flexible Graphite Sheet

This is an all graphite material containing no resins or inorganic fillers. It is available with or without a metal insertion, and in adhesive-back tape form. Flexible Graphite has outstanding resistance to corrosion against a wide variety of acids, alkalies and salt solutions, organic compounds, and heat transfer fluids, even at high temperatures. There are two proven metal reinforced flexible graphite laminate materials ideal for 95% of all sheet gasket applications. Lamons flexible graphite laminates (LG-SS and LG-TC) are surface branded for easy identification. These gasket materials meet refinery, petrochemical and industrial service requirements.

Lamons LG -SS
LG-SS is a flat metal 316/316L stainless steel reinforced flexible graphite sheet material made with minimum 98% typical carbon content.

Lamons LG -TC
LG-TC is a reinforced flexible graphite sheet material laminated with tanged 316/316L stainless steel insert and made with minimum 98% typical carbon content.

Lamons LG - L
LG-L homogeneous graphite sheets are manufactured from high carbon content of minimum 98% natural graphite.

Graphite Tape
Rolls of graphite tape can be furnished with a strong self-adhesive backing strip, to facilitate repair of multiple surfaces, enhancement of existing design or installation as a form-in-place gasket.

Mica Sheet

Mica sheet is a readily-processible form comprised of a high percentage of minerals held together with small amount of silicon binder. Its lamellar and non-fibrous structure, together with the low ratio of binder allows for a significant reduction of weight loss at elevated temperatures, and especially when compared to other high temperature compositions. It resists a wide array of chemicals and is unaffected by water, acids, bases, solvents and mineral oils.

Ceramic Fiber

Ceramic fiber is available in sheet or blanket form and makes an excellent gasket material for hot air duct work with low pressures and light flanges. It is satisfactory for service up to approximately 2000ºF (1093ºC). Ceramic material is also used as a filler material in spiral-wound gaskets.

Optimum Gasket Seating Stress
Non-Metallic
Gasket Type Minimum [PSI] Optimum [PSI] Maximum [PSI]
Thickness 1/16" 1/8" 1/16" 1/8" 1/16" 1/8"
CNAF 3,800 4,100 6,000 6,000 210,000 8,000
Rubber 200 1,000 2,000
LG-SS 900 3,600 18,000
LG-TC 2,500 10,000 20,000
Matrix
L-100 2,175 6,000 10,000
L-104 1,595 5,000 10,000
L-110 1,740 6,000 10,000
L-120 1,000 5,000 9,000
Virgin Teflon 2,150 4,500 7,000

 

Note: Optimum Gasket Stress is based on gasket performance at moderate internal pressure. When working with high internal pressure applications please contact Lamons Engineering Department for clarification. This email address is being protected from spambots. You need JavaScript enabled to view it.

Minimum gasket stress is based on the Y factors of the gasket.