Gessner Glossary

Basis weight
The weight of a unit area of a nonwoven, measured according to the following test procedures TAPPI T1011, TAPPI T410.   Within Gessner Technical Materials it is commonly expressed in grams per square meter (GSM)

Bicomponent fibers
are fibers that is formed having two different and distinct polymer components. Examples include a fiber containing both a polypropylene and a polyethylene section or a fiber containing a section of polyester and a section of a lower melting point polyester.  The lower melting point section of a bicomponent fibers is often used to assist in thermally bonding the bicomponent fiber to a staple fiber having a higher melting point.

It is the process in which a nonwoven is compressed between heated rollers.  The pressure exerted, the roll temperatures and throughput speed are adjusted to optimize the physical characteristics including thickness, tensile strength, porosity and surface smoothness for specific applications.

Composite nonwoven
a nonwoven made of two or more distinct layers which are bonded thermally, mechanically or with an adhesive.

Craneglas® nonwoven
a wet laid nonwoven made from short cut electrical grade glass fibers and a small amount of polyvinyl alcohol to act as a binder

Cranemat® nonwoven
a wet laid nonwoven made with short cut polymer fibers which are thermally bonded during the drying process.

Curtain coating
Is a waterfall or continuous flow of saturants onto a substrate, this process is usually followed by vacuums to remove any excess. 

Dry laid process
a manufacturing process in which fibers are typically fed through one or more barbed rollers called cards which separate and align the fibers. Multiple carding rolls can be used to layer the structure to create composite structures.  Dry laid nonwovens are often then needle punched, hydroentangled (spunlace), stitch bonded or thermally bonded to improve tensile strength and minimize delamination in multilayered structures. 

Electrical grade fiberglass “E-glass” 
is fiberglass that has a composition of alumino-borosilicate glass with less than 1% w/w alkali oxides. Our Craneglas® products are all made from continuous chop E-glass.

Ethyl vinyl acetate (EVA)
also known ethylene vinyl acetate is a copolymer of ethylene and vinyl acetate.  Typically between 10 to 40 percent  by weight of the polymer chain is vinyl acetate.

Membrane Bioreactor (MBR)
combines a membrane separation process such as Ultrafiltration or Microfiltration with a suspended growth biological waste water treatment. It’s commonly used for industrial and municipal waste water treatment.

Membrane support substrate
also sometimes called  membrane support fabric or membrane casting substrate or membrane support backing or backing fabric or backing substrate.  It is generally consists of a light weight, highly uniform wet laid nonwoven made from either polyester or polyolefin fibers that is calendered to reduce thickness and porosity, increase tensile strength and make the surface smooth for membrane casting.   

are very fine fibers having a diameter of less than 1.0 denier or having a diameter of less than 10 microns.

Microfiltration (MF)
a separation process using membranes with a pore size between 0.1-5µm. It’s relatively high pore size allows to operate it under low pressure and thus low energy. Microfiltration membranes are used in a variety of applications but typically for specialty applications and as pre-filter for Reverse Osmosis membranes. Flat sheet membranes require a wet-laid nonwoven as a support fabric.

Micron “µ” or Micrometer “µm”
Is a unit of measure used to represent fiberglass thickness or diameter. Our Craneglas® nonwoven material is made of shortcut fiberglass with a variety of fiber diameters. The fiberglass industry uses alphabetic nomenclature to describe these different fiber diameters ranges from “D” measured at 5µ to “T” which is measured at 24µ.

Nanofiltration (NF)
a liquid filtration process that pushes water through a semi-permeable membrane. It has a pore size range between 0.001-0.01µm. It is often used for specialty applications. A typical configuration is the spiral wound element which includes membrane sheets made out of a polysulfone and a polyamide layer (cast) on a nonwoven backer.

a thermoplastic polymer having a chemical name of polyethylene terephthalate, abbreviated (PET).  It  can be readily processed into fibers for nonwovens using wet laid and air laid technology.   Polyester nonwovens can also be fabricated directly from the resin using spun bond and melt blown technology.

Polyvinyl alcohol
Abbreviated (PVOH) or (PVA) is a water soluble organic polymer. Our wet laid nonwovens are thermally bonded and the solubility and melt temp of PVA make it an ideal binder.

Also referred to as air permeability, is a term used by nonwoven manufacturers describe the degree resistance offered by the nonwoven to the passage of air through a fixed area of the material at a specified pressure, measured according to the following test procedures ASTM D 737, TAPPI T251, EN ISO 9,237.   .  It is usually expressed in the following terms:  cubic feet per minute per square foot at a pressure of 0.5 inches of water in English units or liters per square meter per second or cubic centimeters per square centimeter or cubic decimeters per second per square meter at 200 PA in metric units.

Reverse Osmosis (RO)
a water purification process that pushes water through a semi-permeable membrane. It has a pore size range between 0.0001 – 0.001 µm, filtering out salt and metallic icons. Reverse Osmosis is used for brackish and seawater as well as for filtering tap water in private households. A typical configuration is the spiral wound element which includes membrane sheets made out of a polysulfone and a polyamide layer casted on a support substrate.

The process of cutting a master roll of product into multiple narrower rolls as per our customer specifications.

Staple fibers
are fibers having a homogeneous composition which are formed and cut to a definite length.

Regarding our Craneglas® product line a substrate is a base material used for fabrication of some kind i.e. saturation, corrugation, gluing, forming, or encapsulation. 

Thermal conductivity 
This is a measurement of how much heat a material will conduct. You determine a material’s thermal conductivity by testing the rate at which heat passes through in a specified time. Our Craneglas® products have low thermal conductivity making them a good candidate for thermal or electrical insulation/gasketing. The thermal conductivity readings for our Craneglas® products span from 0.0339 W/(m*k) at 55°C to 0.0586 W/(m*k) at 197°C depending on the thickness and basis weight of the product.

Ultrafiltration (UF)
a separation process using membranes with a pore size between 0.1-0.01µm. Ultrafiltration membranes are often used in specialty applications in the pharma industry, dairy and food industry as well as electronic industry. Hollow fiber, tubular, and plate and frame are typical configurations. Tubular and plate and frame configurations often require a membrane casting substrate made out of Polyester (PET) or Polypropylene (PP).

UL 94V-0 flammability rating 
Underwriters Laboratories is an independent organization in the U.S that controls and certifies product safety. UL 94 is “the standard that test for flammability of plastic materials for parts in devices and appliances includes small scale test that evaluate the flammability of polymeric (plastic) materials, used for parts in devices and appliances, in response to small, open flame or radiant heat sources under controlled laboratory conditions”- as defined by UL. The UL 94V rating systems is their vertical burn test that varies from V-2 (least flame retardant) to V-0 (most flame retardant). Two of our Craneglas® product series hold the UL 94V-0 flammability rating certification. This means these products stop burning within 10 seconds and drips of particles are allowed if they are not inflamed. This rating is usually required for our customers servicing the appliance gasketing markets.

Wet laid process
a manufacturing process in which short cut fibers are dispersed into an aqueous slurry. The slurry is feed into a head box which spreads the dilute solution evenly across a forming screen under vacuum to remove excess surface water.  The damp nonwoven is then fed into a drier system which evaporates the remaining water and softens the fiber surface to bond the fibers.