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Frequently asked questions

1. What is polyvinyl chloride (PVC) window film?

PVC is the abbreviation for Polyvinyl Chloride and one of the most widely used plastics in the world. It is a stable, inert and flexible plastic. What makes PVC so interesting compared to other plastics is that the raw materials are affordable and that PVC is easy to process. Moreover, PVC is extremely stable, wear-resistant, light and durable.

Three types of plastic are in use on the market:

  1. Calendared
  2. Extruded
  3. Pressed

Each type is named after the method of manufacture (production method).

The composition of the basic ingredients of all three types of PVC is identical. The difference lies in the quality of the surface finish which determines the degree of optical clarity.

The intensely polished surface of the 'pressed' PVC is the best finish currently available but is not as flexible as the Extruded and Calendared PVC. That is why the pressed PVC is supplied in sheet form and the other two PVCs in rolls.

The most sold product at Wendt is PVC window film. Depending on the use and applications, different types of PVC are possible. The PVC window film is used worldwide in the maritime, tent or industrial sector.

2. What is CSM rubberized fabric

Achilles CSM rubberized fabric is used for, among other things, making inflatable boats and other maritime applications where CSM fabric can be used. CSM rubberized fabric owes its name to the top layer of CSM (Chlorosulphonopolyethylene Rubber).

Achilles is one of the few boat companies that manufacture its own CMS fabric for Inflatable boats.

The CSM rubberized fabric consists of four layers:

  • The double-layer neoprene on the inside ensures optimal airtightness.
  • The heavy-duty polyester core guarantees durable and long-term use.
  • The outer layer is reinforced with CSM and is better known as Hypalon®.

Hypalon® rubber is the most commonly used term to describe CSM rubber. Hypalon® is a registered trademark of DuPont. Hypalon® was developed at DuPont around 1947 and the name has developed into a generic name for all CSM, including those of other manufacturers who use other brand names. DuPont itself stopped producing Hypalon in April 2010.

When producing RIBs or inflatable boats, a CSM or Hypalon® outer layer offers better chemical resistance, ozone and light resistance, heat ageing than PVC.

The specific resistance to challenging weather conditions and excellent low gas permeability present CSM as the best option for the production of inflatable boats for all environments, but especially in sea defences. Because Hypalon® is also highly resistant to salt water.

3. What does the (S) or (PHR) value indicated on the datasheets mean?

PVC film is available in different hardness. When talking about the hardness or flexibility of transparent PVC film this is expressed in terms of 'hand' or 'PHR'.

PHR stands for Parts per Hundreds Rubber. This is a size used by chemists in the rubber industry.

When thermo hardening resins are mixed, it is important that the right amount of hardener is used to achieve a certain hardness. This hardness is expressed in H or S.

The most common hardness of our PVC film are 3S, 4S and 6.5S. However, this does not mean that one type of film hardness is better. It often has to do with a certain preference or application of the person processing the film.

For example, 2S is used more frequently in southern European countries due to the higher temperatures that make PVC film softer.

Overview of HAND and PHR values. The larger the PHR value, the softer the film.

Scale of hardness of window films:

21 PHR - 4H
25 PHR - 3H
29 PHR - 2H
33 PHR - H
37 PHR - S
41 PHR - 2S
45 PHR - 3S (most common)
47 PHR - 3.5S
49 PHR - 4S (most common)
53 PHR - 5S
55 PHR - 5.5S
57 PHR - 6S
59 PHR - 6.5S (most common)
61 PHR - 7S
65 PHR - 8S

4. Does PVC film shrink?

All materials react to the ambient temperature so does the PVC film. Almost all materials expand when they become hot and shrink when they cool down. The phenomenon of shrinkage at higher temperatures is called negative thermal expansion (NTE). The materials that do this usually have a very complex structure. In addition to warm temperatures, cold temperatures also affect PVC window film. This means that there is minimal shrinkage for low temperatures in both length and width. Wendt's PVC window film has good resistance to shrinkage at high temperatures and has an average shrinkage of between 2-3%. Film shrinks in both directions.

As a solution, we developed the Vinistar Low Shrink. A low shrink PVC window film that shows little shrinkage even at extremely high temperatures - up to 60 degrees Celsius 0% shrinkage. At cold temperatures our Achilles PVC window film shrinks by 0.03% at -50 Celsius.

If you are not using Vinistar Low Shrink PVC window film, we recommend that you take the PVC film from the roll 24 hours before processingit in the end product



5. Is PVC window film UV stabilised / Does PVC window film discolour?

Yes, all our PVC films are UV stabilised. In practice, this means that our PVC films have good resistance to UV radiation.

Our PVC films can be exposed to direct sunlight for an average of 10000 hours. This has been tested with the so-called "wheatherability hours" test. This is a method to test the UV stability of PVC films. This means that our PVC films will last 2-3 years before they start to discolour in sunlight.

In addition, our PVC film blocks approximately 93% of harmful UV rays (A-B radiation). Too much exposure to UV rays can be harmful to the skin. So, an additional advantage for Wendt's PVC films is that they block the harmful UV radiation.

6. What do the indicated values on the datasheets mean?

Tensile force: The force in Newton needed to break 1cm of material. Tested at 1cm of the thickness of the production material. The higher the number, the more force required to break the material, the stronger the product.

Tensile strength: is a measure to classify the mechanical properties of a material. It is expressed in N (Newton) and indicates how well a material resists the effects of strain. The amount of force in N (Newton) required to produce a crack in the tested material.

100% Elasticity: The strength in N (Newton) required to make material of 1 cm x 1 stretching cm twice as big. This test is the same and calculated in the same way as the tensile force test. The higher the number, the harder the material is and the more force is needed to stretch the material.

Stretch length : The amount of increase in length, reported as a percentage of the original length. The material is stretched until a breaking point is reached. The higher the number, the more a material can be stretched.

Cold Crack: PVC becomes hard and brittle when exposed to cold. This can cause the material to crack or split. This effect is called 'cold crack'. The moment at which the PVC film cracks at a temperature below 0 is indicated in degrees Celsius.


Light permeability: This indicates how much light or transparency a PVC film is. On the datasheets this is expressed as a percentage. The higher the percentage, the more light a foil transmits and the more transparent the foil is.


Surface resistivity: is the resistance to leakage current along the surface of an insulating material. Volume resistance is the resistance to leakage current through the body of an insulating material. The higher the surface/volume resistance, the lower the leakage current and the less conductive the material is.

Static decay Time (sec):

Oxygen Index:

M.D.: This abbreviation refers to the direction of the PVC window film M.D. : Machine Direction (Lenghtwise). This is the roll length of the window film.

T.D. : This abbreviation refers to the direction of the PVC window film T.D. : Transverse Direction (Crosswise). This is the roll width.

7. Is PVC film suitable for bonding to windows in order to meet fire safety requirements?

No, PVC film is not suitable for bonding to windows in order to comply with fire safety requirements.

The PVC  film has a German B1 (DIN 4102) and French M2 certificate for fire retardancy. Sticking the PVC film on windows does not meet the specific fire safety requirements that apply to buildings and fixed structures

8. What does REACH conform mean?

REACH is a European regulation on the production of and trade in chemicals. It sets out what companies and governments must comply with. REACH stands for: Registration, Evaluation, Authorisation and Restriction of Chemicals. This regulation applies to all countries of the European Union.

Producers and importers of chemical substances must register all substances they produce or import. When registering, the producer or importer must indicate, among other things, whether the substance is harmful to humans or the environment. And how a user can handle the substance safely.

Achilles has adapted the production of films to meet the strict REACH standards. In so doing, it is taking on its responsibility towards people and the environment. After all, with this new wording, the impact on the environment and the harmfulness to human life are reduced to a minimum.

All products are now manufactured with safe, environmentally friendly formulation. With this, Achilles takes the lead in the production of transparent PVC products.

9. What does B1 or M2 fire retardancy of PVC film mean?

A number of our PVC window films have the property of being fire retardant. A fire-retardant film can help to slow down or prevent the spread of flames. Public events, shopping centres, theatres or care institutions must meet the requirements of the fire brigade. A fire-retardant film can help to meet these requirements.

In Europe, there is a set standard for fire safety. This is the EN1350-1 classification for fire resistance.

There are seven Euro fire classes: A1, A2, B, C, D, E and F.

Where class A1 has the best performance, namely non-flammable and class F is highly flammable.

Euro fire class:

A1 & A2 Little or no contribution to the development of a fire

B A very small contribution to fire

C Limited contribution to fire

D contribute to the development of fire

E contribute to the development of fire and can only minimize the risk of fire.

resist ignition source

F contribute greatly to the development of fire, do not meet any of the above qualifications and/or are assigned to building materials without the necessary test reports

Fire retardant films from Wendt with official German B1 (DIN 4102) and French M2 certificates:

Vinistar FRX-EX - 0.50mm x 137cm x 50m - 3S

Vinistar FRX-EX Wide - 0.50mm x 183cm x 30m - 3S

In addition, our Achilles PVC film produced in the United States has the American MVSS302 (Federal Motor Vehicle Safety Standards) certificate.

  • Crystal View FR - 0.75mm x 183cm x 30m - 3S

If you need a specific certificate for fire retardancy that our products do not currently have, we can look together at what we can do for each other.

10. How can I weld (process) PVC film?

Wendt PVC film can be processed in various ways. The best ways to do this  differs from one industry to another and from application to application. Here are the most common ones:

  • · Stitching
  • · Hot air welding
  • · High-frequency welding

PVC film is often stitched in smaller tents and sprayhoods.

Larger window opening as with porch sails and party tents is welded. This can be a high frequency weld or by means of hot air.

Nowadays, end-side welding is becoming increasingly popular because the weld is less visible and optimises the appearance of, for example, a porch tarpaulin.

*The Achilles Vinistar Scratch Resistant and Achilles Seiden F cannot be welded and we advise against this.*

11. How is PVC film packed and shipped?

Our PVC film is always supplied on a roll and is packed in a white cardboard box to protect the material.

The amount of PVC film on the roll varies and depends on the thickness and width of the roll. It is important that the rolls do not become too heavy and remain easy to process. That is why we optimise packaging for processing.

In the base all deliveries are placed on a pallet and shipped. For orders of 1 roll that are 30 kg or less than 30 kg weighing Wendt works with various courier services and is shipped loose by roll within the Netherlands and Europe.

12 How can I order a "sample" of PVC film?

By going to our product page. Here you will find an overview of differen qualities of PVC films that best match your requirements. By clicking on the "request a sample" button and leaving your details, we will ensure that you receive a sample.

If you are looking for a material that you cannot find in our overview please feel free to leave us a message on our contact page  so we can get in touch to see what we can do for you.

13. My film has a white haze - What can I do about it?

A white haze on PVC film often occurs when PVC film has been in a humid environment for a long time or has not been able to dry properly and has been stored. This means that PVC film has absorbed moisture and therefore a white haze is visible on the film.

By allowing the PVC film to dry properly, the white haze itself will diminish over time and in many cases disappear altogether. We always recommend that the PVC film is allowed to dry thoroughly before it is stored and that it is not placed on a damp surface for long periods of time. The best tips for handling PVC film and CSM fabric can be read here and here.

Another possibility is that the PVC film reacts to the composition of another material or substance. Try to find out for yourself when the white haze arose and whether it was caused by a particular substance. By preventing this in the future the white haze will also decrease.

Here you can read more about the maintenance of PVC Film.

Do you have any questions?

Have your questions not been answered? Please feel free to contact us by calling +31 (0) 252 516 938 or send us a message and we will contact you.


Wendt Agenturen B.V.
Heereweg 21
2161 AC Lisse

Telephone: +31 (0) 252 516 938 
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