FAQs

Click on a link below for further information:

Dimensions

• Can you make the foam sheet to the size I want?

  Zotefoams foaming technology is very flexible and currently a wide range of sheet sizes are available, subject to volume demand. Often a fabricated solution is more economical and as a first stop you should discuss this with your local supplier or our sales team. However, we are always willing to consider new developments to meet customer demand.

• If I needed a piece of foam thinner, thicker or different sheet size to your standard, is this possible?

  Yes this is easy! The foams are widely converted into other sizes for final use (contact your local supplier for further information).

  Thickness - thinner sheets (down to around 2mm) can be obtained by splitting (skiving) the sheet. Thicker sheets can be fabricated by either heat laminating sheets together (up to around 300mm) or by adhesive bonding.

  Length and Width - can be cut using simple equipment such as bandsaws, etc. Other methods used are die stamping, water jet cutting.

• In what density are the foams available?

  The product range covers:

  High density products between 115 kg/m3 down to 70 kg/m3v

  Medium density products between 70 kg/m3 down to 33 kg/m3v

  Low density products between 33 kg/m3 down to 15 kg/m3

  Our ultra-low density product Plastazote® LD15 has a nominal density of 15 kg/m3 making it the lowest density crosslinked polyethylene foam in the world today.

• What are the standard sheet sizes?

  The standard sheet size of the foam as it leaves our factory will vary by polymer grade and density. As a guideline, the most popular products are available as a sheet which is 2000mm x 1000mm x 30mm but it is best to speak with our sales team before doing any detailed design or specification.

• What if I need a thicker sheet than your standard?

  Thicker foam sheets can be achieved by standard heat laminating of the foam sheets. A block thickness of up to 300mm can be achieved. If greater than this is required then adhesives may need to be employed.

  When viable we can manufacture sheets to a specific thickness. This will need to be discussed with our sales team.

• What is density and what does density affect?

  Density is a measure of weight per unit volume. The SI unit is:

  kg/m3 (kilogram per cubic metre or kilogram per metre cubed)

  The raw material, low density polyethylene, has a density of around 920kg/m3. Our foams you will see have a density in the range of 15kg/m3 to 115kg/m3.

  Volumetrically foam has much less weight than the solid (between 8 and 60 times). This means a huge weight saving in applications where either a solid material or a higher density foam can be displaced.

  Density is often one of the main criteria for comparing and selecting foams as it defines many of the foam properties. In general lower density foams of the same plastic have lower properties, although certain characteristics such as thermal conductivity and buoyancy can be improved.

  In the US the normal density measure is still the imperial measurement of the pound per cubic foot (lb/ft3 or pcf). To convert pcf to kg/m3 simply multiply by 16.

• Where can I get a sample in the size I require?

  Zotefoams supplies A5 size samples at 10mm thick free of charge on request. If you require specific sample dimensions for prototyping please contact our customer service team who will do their best to meet your requirements.

Buying

• Can I buy a sheet of foam from you?

  Zotefoams is large scale manufacturer of foams and we normally sell bulk quantities to converter/distributors. They are therefore better placed to service your needs on a daily basis.

• How much does the foam cost to buy?

  This very much depends on the grade of product, and level of fabrication required. Zotefoams foam converters are the best route to gain rapid price guidance.

Special Properties

• Are the foams able to absorb moisture like a sponge?

  The answer is no because our foams are all ‘closed cell’ - sponge materials may be classified as ‘open cell’:

  In closed cell foams the plastic is the only continuous phase (this is like having millions of small bubbles of plastic all bonded together) and therefore the gas in the foam is trapped inside the bubbles.

  In open cell foams both the gas and the plastic are continuous phases. In this case when you squeeze the foam you expel all of the gas from the structure, but when you release it (like a sponge) it sucks air back into the structure.

  Practically this means our closed cell foams will not absorb significant amounts of water or other liquids, which is great for buoyancy and for seals and gaskets.

• I need a flame retarded product – are the foams flame retardant?

  Polyethylene will burn vigorously and yield high levels of thermal energy in the process unless modified with an additive. Zotefoams produce a range of flame retardant foams complying with national and international flammability requirements. These include aerospace standards (CS25.853), automotive standards (FMVSS 302), electronics standards (UL94) and many other industry specific standards.

  If you have a specific flammability specification or requirement then please discuss with our Technical Service team.

  Additionally, work has been undertaken to develop a halogen free flame retardant foam. If this is of interest then please contact the sales team for more information.

• I need to package equipment that is sensitive to electrostatic discharge (ESD) – do you have any suitable material?

  We have conductive and static dissipative foams that can be used to protect materials susceptible to ESD. For more information please refer to our Technical bulletins on Conductive foam (TIS 16) and Static dissipative foam (TIS17) or contact our technical support team.

• I want to package a very sensitive piece of equipment – what foam is best?

  Zotefoams foams are unchallenged in the performance packaging industry in terms of consistency and level of performance.

  Cushion packaging design is a skill and for sensitive electronics and/or munitions, a great deal of thought is required. There are a number of factors which must be considered including the size, weight and shape of the article, the fragility (ease of damage from impact), vibration effects and long term storage effects, likely drop height of any impact.

  Zotefoams itself does not design packaging systems. We support applications with information such as cushioning curves, creep curves, vibration attenuation curves, etc. Do not hesitate to contact the technical services team should you require more information.

• My application is for body impact protection, which foam should I use?

  This is a difficult question to answer: our HD grade foams show the highest energy absorption in static compression and perform adequately in higher speed impacts. However, they are relatively rigid materials and therefore may be less comfortable if you need to have the protection directly against the skin.

  LD grades offer a compromise in stiffness (comfort) and energy management. VA and EV grades are much more resilient so would tend to deflect an impact (rebound) rather than absorb the energy of impact.

  Combinations of the above with or without other materials can be used to achieve performance targets. For applications such as this please contact either our sales or technical service teams.

• What is the difference between FR and FM material?

  FR and FM materials have been developed to meet the fire retardancy standards for different applications. The FR materials are suitable for aviation applications. The FM materials have a lower percentage of flame retardant additive and meet the standards for the automotive industry. For further information on the standards these materials comply with please refer to the relevant property datasheets or the technical literature of fire retardancy

Converting/manufacture

• I think my application would require a moulded part – can the foam be moulded?

  The foams can be easily moulded by known techniques such as hot press forming (compression moulding) or sheet thermoforming (vacuum forming), as well as other techniques including embossing, etc. Good mouldings can often be achieved with very simple equipment.

  The forces necessary to mould foam are low and therefore wooden or plaster moulds can be used unless very long runs are likely.

  Alternatively the hot foams can easily be formed to shape by hand using techniques developed in the medical industry, the hot foam can be shaped directly onto the body with no irritation or burns risk if guidance is followed.

• What adhesive can I use or how can I bond my foam to other foams and/or materials?

  Bonding foam to foam is possible without the use of adhesives using techniques such as heat laminating. Our Technical Guidance Bulletin, TIS 15, lists some of the information you will require to select an appropriate adhesive and also some known adhesive types and suppliers to aid the selection process.

  Bonding foam to another material (such as aluminium) we would always advise you contact the adhesive manufacturers and discuss the materials and requirements in detail.

General

• Are the foams compliant with the latest European directives?

  Our foams are compliant with the requirements of the European directives, 2000/53/EC ('ELV'), 2003/11/EC and 2002/96/EC ('WEEE') as far as the materials fall under these regulations. General statements confirming this compliance can be downloaded from the regulations sub-section in the Downloads section.

• What colours are available?

  A wide range of colour options exist for the most popular grades of foam. For primary colours we would advise you to contact local suppliers to discuss your exact requirements.

  Our technical team also has expertise in colour matching to specific requirements or industry standard colours.

• What does ‘nitrogen expanded foam’ mean and how does it benefit me?

  Zotefoams products are manufactured using a truly unique process technology. This involves dissolving nitrogen gas into a plastic sheet at extreme pressures and temperatures. On releasing this pressure and temperature the gas increases its volume to such an extent that it expands the plastic into a foam.

  Most of our competitors use either volatile / flammable gases or chemicals / blowing agents which at a certain temperature decompose to produce nitrogen gas (along with other gases such as ammonia). Both of these have negative aspects. The practical benefits are that in emissions studies our foams tend to yield far lower levels of volatile substances. In automotive applications, our foams have among the lowest fogging values in the industry (Fogging is the mist that forms on the inside of your car windscreen over time and is attributable to volatiles in the plastics used in the car interior).

  In medical applications the purity is of great benefit for obvious reasons and in packaging of valuable or rare artwork our products have ensured safe transport and storage for many users.

• What information is contained in the Download section?

  In the Download section you can find general information on our products as well as product information sheets, materials safety datasheets, technical bulletins, technical datasheets, statements regarding general regulations and test certificates.

• What is the maximum operating temperature of the foam?

  Polyethylene has a melting point below 110°C (230°F). As we cross-link our product, this enhances the thermal stability but as you approach this temperature the foam will tend to shrink at an increasing rate.

  Zotefoams product information sheets are based on a specific 24 hour test for 5% shrinkage of a foam piece. Many variables affect shrinkage such as time, temperature, dimensions, humidity, cell size, density, application of a load and even colour. We advise testing and measurement to ensure the correct material is selected.

  ZOTEK foams, based on advanced polymers have considerably higher working temperature limits than do polyolefin foams. ZOTEK N, based on polyamide (nylon) has an upper limit some 100C higher than similar density polyethylene foams.

• What is the shelf life of your foam?

  The shelf life of the foam is limitless. In most applications the foams have withstood many decades of use without failure.

  In harsh chemical environments or under intense and continuous exposure to solar radiation the lifetime may be reduced to years but if predicted beforehand there are means to enhance performance. Please contact the sales or technical service team if you wish to discuss your application further.

• What materials are the foams made from?

  Our AZOTE® brand foams are all made from polyolefins, which is a family of synthetic plastic materials that includes low density polyethylene (LDPE), co-polymers of ethylene such as Ethylene-Vinyl Acetate (EVA) and high density polyethylene (HDPE). In detail the raw materials by grade are:

  Plastazote® LD = Low Density Polyethylene

  Plastazote® MP = Metallocene Low Density

  Polyethylene Plastazote® HD = High Density Polyethylene

  Evazote® EV = Ethylene-Vinyl Acetate (High VA content)

  Evazote® VA = Ethylene-Vinyl Acetate (Low VA content)

  Supazote® EM = Ethylene-Methyl Acrylate

  These raw materials then dictate how the foam will feel and perform, for instance our HD grade foams (HDPE) are rigid, absorb high levels of energy and have good temperature stability, whereas an EV grade foam (EVA) is soft, resilient but lacks the high temperature stability.

  Our ZOTEK® high-performance foam range is produced from engineering polymers that boast a range of special properties that are prized in the most demanding applications: ZOTEK F is made from polyvinylidene fluoride (PVDF), ZOTEK N from polyamide 6 (nylon) and ZOTEK T from thermoplastic elastomers (TPE).