Wednesday, 21 March 2012

Benefits of PVDC over PVC as a primary packaging material

PVC(Polyvinyl chloride) and PVDC(polyvinylidine chloride)are used in pharmaceuticals as primary packaging materials,which protect pharmaceutical product against Oxygen and odour permeation,moisture and water vapour transmission and microbial attack.

PVC forming film is called rigid PVC because it is almost free of softening agents and plasticizer. Without plasticizers, PVC blisters offer structural rigidity and physical protection for the pharmaceutical dosage form. The blister cavity must remain accessible by the push-through effect and the formed web may not be too hard to collapse when pressed upon. That is why, PVC sheet thickness is typically chosen between 200µ to 300µ depending on the cavity size and shape.

Rigid PVC is a very clear, stiff material with a low WVTR. It exhibits excellent thermoformability; a high flexural strength; good chemical resistance; low permeability to oils, fats, and flavoring ingredients; easy tintability; and low cost. These properties make rigid PVC the material of choice for blister packaging, and it essentially has 100% of the market for the plastic component. PVC films that are thermoformed have a thickness of about 10 mil. The main disadvantages are the poor barrier against moisture ingress and oxygen ingress; moreover PVC has a negative environmental connotation due to its chlorine content and highly toxic dioxins.

Most PVC sheets for pharmaceutical blisters are 250µ or 0.250 mm in thickness. Typical values for the Water Vapor Transmission Rate (WVTR) of a 250µ PVC film are around 3.0 g/m2/day measured at 38°C/90%RH and the Oxygen Transmission Rate (OTR) is around 20 cc/m2/day. In order to overcome the lack of barrier properties of PVC film, it can be coated with PVDC or laminated to PCTFE or COC to increase the protective properties. Multi-layer blister films based on PVC are often used for pharmaceutical blister packaging, whereby the PVC serves as the thermoformable backbone of the structure. PVC layer can be colored with pigments and/or UV filters.

Polyvinylidene chloride (PVDC)–coated PVC. PVDC plays a critical role in blister packaging as laminations or coatings on PVC. PVDC can reduce the gas and moisture permeability of PVC blister packages by a factor of 5–10. Coated PVC films have a thickness of 8–10 mil; the thickness of the PVDC coat amounts to 1–2 mil. The coating is applied on one side and usually faces the product and the lidding material.

PVDC provide excellent barrier to both oxygen and water vapor while most other barrier polymer offer just one or the other. The gas barrier properties are unaffected by relative humidity, do the performance can be relied on through a wide range of packaging and environmental conditions. All PVDC products on the market are actually copolymers of vinylidene chloride (VDC) and other comonomers. The relative amount of VDC in the copolymer dictates some key properties. With more VDC, the barrier properties are generally better, with less VDC, flexibility usually improves. However, the amount and type of comonomer as well as other additives and processing technology used, will influence other properties such as sealing, surface properties, transparency, glossm coefficient or friction, etc. PVDC coatings have been used with duplex (PVDC/PVC) and triplex (PVDC/PE/PVC) structure being the most common ones used. Approximately, 67% of the barrier blister packaging market uses these PVDC-coated films. Typical coating weights used include 40, 60, 90 and 120g/m2, with the WVTR for a ty pical 120 g/m2 PVDC-coated PVC film being arounf 0.16 g/m2 at 40 oC and 75% RH.






19 comments:

  1. These are good inspirations about PVC Sheets, thanks for sharing. It is greatly impressed on the post you have written. This post is a big help for me.

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  3. Nice and very inspiring post here. Thanks for sharing this post. Pepsi machine manufacturer

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  4. Genuinely loved this kind of post. Although I want much more information on like precious subject matter.

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  5. Chamari Gunathilaka

    Can you know how to check whether there is a PVDC layer on PVC or not?

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    Replies
    1. by morpholine test, if you apply morpholine(few Drop) on the film, the PVDC side will strat brounish after few seconds of application

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  6. Thanks for sharing this with us! Some really amazing features.
    BLISTER PACKING MACHINES MANUFACTURER

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  7. HI,
    could you please to tell me which one is contacted with Aluminium foil? PVC or PVDC? Thank you

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  8. I have been reading your posts regularly. I need to say that you are doing a fantastic job. Please keep up the great work.
    BLISTER PACKAGING MACHINES MANUFACTURER

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  9. We called the film thickness which is less than 1um film, the film thickness is higher than 1um thick film coating process is called with different materials on the
    substrate surface to form a new surface method.
    It requires to have a very film thickness adhesion, adhesion is not strong is called coverage.
    We can see more: film thickness

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  10. PVC sheets are highly lit with sunlight, even those areas with large temperature variances during the day or from season-to-season can benefit from these properties.
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  11. Good information illustrate, which help to gettong up to date with primary packaging material for pharmaceutical

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  12. Good information. I would to ask a question to all. In this blog it is mentioned that PVDc coated side in touch with product and sealing side, but in all pharmaceutical industry following to keep pvdc coated side on the outer side of blister. Can anybody tell about this thing ??

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  13. Pvdc coating is the increase high barrier properties in flexible packaging film .

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  14. JUST NOW I READ THE ARTICLE, PVDC COATED SIDE SHOULD COME OUT SIDE ONLY, NOT INSIDE.
    THAT IS WHY FILM SUPPLIER ALWAYS MARK AS " COATED SIDE ".

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    , shelf ready trays, slitting of rolls of plastic, sheeting of plastic, vacuum forming products manufacturer and thermo formed packaging for many different needs.

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  16. PVC-PVDC, PVDC or PVC should contact with product (tablet) and why?

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  17. is there any effect on drugs? or due thickness of PVDC, direction of pvdc is defined?

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  18. Thanks for the explanation!
    To measure coating thickness, you could also use Elcometer

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