
What is BV film packing material? Most people have never heard of BV film. Simply put, BV film is a new type of film made by specially processing two materials, BOPP and PVA. In other words, BV film is a BOPP film coated with a PVA layer, which supports compounding with a variety of other materials to enhance physical properties and achieve packaging needs.
Before understanding BV film
We need to know about films that can be used for various food packaging, typically consisting of two or more layers of composite films. They must have the following characteristics: good air tightness (primarily good oxygen barrier properties to inhibit food oxidation and spoilage), moisture resistance, transparency, print adaptability, odorless and non-toxic, oil and water resistance, easy heat sealing, high strength, and low cost.
The performance of composite films depends on the composition of the individual films. Generally, the more layers of composite, the better the performance, but the cost also increases. The simplest composite films are the two-layer Nylon/PE, PET/PE, and BOPP/PE films. The first two have poor moisture resistance and medium oxygen barrier properties with high costs, while the latter has poor oxygen barrier properties, good moisture resistance, and low costs. As the commonly used types of films on the market, none of them can meet the requirements of high oxygen barrier and moisture resistance and low-cost packaging. Therefore, CHALVO’s BV film can be compounded with PE (or CPP or VMOPP) to achieve better performance at a lower cost.
Structural characteristics of BV films
Taking BV/PE composite film as an example, the structural features of the BV/PE coated composite film are as follows: the surface layer BOPP has the characteristics of high strength, non-toxic and tasteless, high transparency, good gloss, and excellent moisture resistance. The middle layer PVA coating has properties of transparency, non-toxicity and tastelessness, low cost, high oxygen barrier, and extremely low oil permeability. Through the cross-linking curing effect of the PVA coating, which is located between the two moisture-resistant layers, the coating not only fully exerts the high oxygen barrier properties of the PVA coating but also provides the most economical and convenient protection against mechanical abrasion and contact with moisture. The inner layer PE (high-pressure polyethylene) film in contact with food has the characteristics of odorless, transparent, moisture resistance, and easy heat sealing. In addition, BV/PE are all low-cost raw materials with sufficient domestic sources.
Production process and conventional structure of BV films
ⅰ.Recommended processing methods: solvent-free composite, non-aqueous gel dry composite, etc.
ⅱ.PVA coating refers to the application of PVA coating solution on films, including PVA coated BOPP film, PVA coated CPP film, PVA coated LDPE film, and PVA coated PET film. The composite film can be completed in one step by directly coating the PVA aqueous solution on the film.
ⅲ.The peel strength between the PVA coating and the printed BOPP surface is related to the type and amount of adhesive used. For several decades, both domestic and foreign plastic composite films have been manufactured using a two-component polyurethane adhesive in dry composite method.
ⅳ.Recommended composite structures:
BV/CPP;PET/BV;BV/VMOPP;BV/VMCPP,ETC
ⅴ.Typical thickness and substrates:
BOPP, BOPET, BOPA, 19µm, 21µm, 27µm, etc., can be customized according to needs.
Properties and Characteristics of BV Films
BOPP films with the addition of PVA high barrier material as a coating layer have very strong barrier properties.
ⅰ.It can extend the shelf life of packaged contents.ⅱ.It has excellent aroma and flavor preservation properties.ⅲ.It has excellent gas (oxygen, nitrogen, and carbon dioxide) barrier properties.ⅳ.Clear appearance and chlorine-free.ⅴ.It can replace aluminum foil packaging when combined with VMOPP.
Performance indicators.BOPP-BV | Indicators | Units | Test method | |
Thickness | 19 | µm | GB 6672-2001 | |
Tensile strength | MD | ≥120 | Mpa | GB/T 1040.3-2006 |
TD | ≥210 | Mpa | ||
Elongation at break | MD | ≤180 | % | |
TD | ≤60 | % | ||
Thermal shrinkage | MD | ≤3.5 | % | GB/T 32021-2015 |
TD | ≤0.2 | % | ||
Dynamic friction coefficient | Coated surface | 0.45 | – | GB/T 10006-1988 |
Non-coated surface | 0.45 | – | ||
Gloss(45°) | 95 | % | GB/T 8807-1988 | |
Haze | 1.1 | % | GB/T 2410-2008 | |
Light transmittance | 92.5 | % | GB/T 2410-2008 | |
Oxygen barrier property | <1 | cc/m2·day | GB/T 19789-2005 | |
Water vapor barrier property | 5 | g/m2·day | GB/T 26253-2010 |
BV films in life
BOPP/PVA composite film is suitable for packaging oxygen-sensitive foods such as baked goods, dehydrated foods, mooncakes, pastries, nuts, coffee, tea, noodles, biscuits, dried fruits, and pet foods.
Advantages of BV films
Due to the excellent film-forming properties and gas barrier properties of PVA, the oxygen flow rate of PVA film in a dry environment is lower than that of nylon of the same thickness and 1/30 of PET; it is also lower than 2‰ of PE or PP film. For example, the oxygen transmission rate of a 0.1mm thick PE film with a 0.001mm PVA coating can be reduced from over 1000ml to below 3ml per 24 hours per square meter. This is very important for preventing or inhibiting bacterial growth and oxidative deterioration of fatty foods in aerobic conditions.
Compared with ordinary packaging films, BV material has stronger packaging functions, better preservation of quality and aroma, and longer shelf life. Compared with PVDC or K coating, BV/PVA composite film has lower cost, stronger gas barrier and aroma preservation functions, higher transparency, healthier packaging methods, more convenient recycling and disposal, and is more environmentally friendly and non-toxic when incinerated.
Comparison between BV and PVDC(K-film) | |||
Index | BOPP-BV | KOPP | Units |
BOPP Base film thickness | 18 | 18 | µm |
Total thickness | 19 | 20.5 | µm |
Coating thickness | 1 | 2.5 | µm |
Density | 0.914 | 1.03 | g/m³ |
Gram weight | 17.4 | 20.6 | g/㎡ |
Output volume | 57.5 | 48.5 | ㎡/kg |
Oxygen permeability(23 ℃,humidity 50%) | < 1.0 | 8 | cc/㎡.day |
Permeable(38 ℃,humidity90%) | 5 | 4 | g/㎡.day |
Recyclability | Waste film and scraps can be recycled | Any K-containing coating film is not recyclable | – |