1. What is PA film?
PA is a widely used resin for the production of flexible packaging film, in most cases combined with polyolefins as a component of a multilayer structure. Polyamides may be processed into a film by blown or cast film process, oriented or non-oriented. Standard extrusion equipment may be used, however, post-treatment by humidification or annealing helps to postcrystallize PA film and to achieve dimensionally stable, ready-to-use film of high quality.
2. Characteristics of PA film
The high polarity
The high polarity of the amide groups is also responsible for the water absorption of nylon resins. Water molecules inserted into the hydrogen bonds provide superior elastic properties, as
- High puncture resistance and toughness
- Good thermoformabilityThe outstanding feature of nylon is the fact that it provides all these properties simultaneously to the film construction. Nylon is therefore chosen when a complex property portfolio is requested from a film construction.
- High barrier to oxygen, carbon dioxide, and many solvents and aroma materials
Nylon shows exceptionally high strength, toughness, and puncture resistance and provides these properties also to multilayer film based on nylon.
As the mechanical properties of nylon film depend on the resin’s water absorption. Water acts as a plasticizer for polyamides, lowering their strength and stiffness while increasing their toughness, drawability, and elasticity. As film rapidly absorbs moisture – surface layers within minutes, but even PA layers shielded by polyethylene layers from the ambient atmosphere within a few days – only mechanical properties after moisturization into humidity equilibrium are relevant.
PA has an intermediate oxygen transmission rate (OTR) that increases at higher humidity levels. Its barrier is 2 magnitudes higher than that of polyolefins, but still 10-100x inferior to high-barrier EVOH.
Nylon shows superior barrier to chemicals of low polarity as hydrocarbon solvents, but also to low polarity aroma substances in food components, like limonene, camphor, vanillin, and menthol. Only with regard to highly polar chemicals that are readily absorbed by nylon, like water, ethanol, or methanol, its barrier is is inferior.
Polyamide is often used in multilayer structures for its high maximum deep draw depth and its ability to maintain as much barrier layer thickness in the corners of the thermoformed, the areas of the deepest draw.
In a multilayer film PE-tie-PA-EVOH-PA, the EVOH’s draw ability is significantly improved compared to a structure where the EVOH barrier layer is not sandwiched between PA layers.
An outside layer of PA provides high heat resistance to a multilayer film structure, allowing the processor to operate at a high sealing bar temperature without sticking the film to the sealing bar surface. Such a film will therefore provide high sealing line speed as well as good seal quality. For this type of film, a well-crystallized PA film – by slow cooling or solid-state post crystallization – is essential to avoid shrinkage of the film in the seal area, which might result in wrinkles and pinholes.
3. Application of PA film in food packaging
The majority of PA films are used as a component of laminated films for the packaging of oxygen-sensitive foods, such as:
- Processed meats (sausages, bacon)
- Smoked fish
- Cheese and dairy products
- Prepared food
In packaging films, the PA layer performs two important functions:
- It slows down the spoilage of packaged foods by creating a barrier that significantly slows down the rate at which oxygen moves into the packaging.
- It minimizes the migration of food flavors from the packaging, thus ensuring the long-term preservation of the organoleptic properties of the food.
In the production of laminated food packaging, the polyamide layer is often combined with layers of polythene or polythene copolymers to create a multi-layer film that provides an effective moisture barrier while ensuring good transparency.
4. Why plastics for packing?
Today, several polymer types are currently used for foodstuff packaging. Plastics have emerged as the most preferred choice of packaging materials for various products- from food, beverages, chemicals, electronic items, and so on. They offer unique advantages over conventional materials:
Safety: Plastics are safer materials for packaging food products especially polyolefins which do not react with food. Pilferage and contamination are difficult.
Shelf Life: Plastics packaging material offer better shelf life
Cost: Plastics are the most cost-effective medium of packaging when compared with any other material, the cost of transportation is reduced considerably on account of lower weight and less damage
Convenience: Plastics can be converted in any form with various processing techniques, thus can pack any type of substances like liquids, powders, flakes, granules, solids.
Waste: Packaging in plastics reduces the wastage of various food products, a typical example is potatoes or onions packed in leno.
Aesthetics: A right choice of plastics packaging increased the aesthetic value of products and helps in brand identity
Handling and Storage: Products packed in plastics are easiest to handle and store as well as transport.
Plastic products are easy to recycle.
Every day there are new products packed in plastics replacing conventional products and when a thought is given to packing a new product the first choice that appears in the mind is Plastic packaging material.
Other interesting page: Applications of CPP film in life
5. A supplier of prestigious and quality plastic films
Union Packaging with many years of experience in the field of providing plastic films and plastic packaging is manufactured from virgin plastic particles and meets FDA standards. Customers can rest assured when cooperating with us because Union Packaging always ensures:
- Customer satisfaction is the number 1 priority
- Outstanding product quality from stable sources of quality goods from Taiwan and China
- Competitive price
- Reputation builds a brand
- Product safety certification
- Fast shipping
- Various payment policies
- Enthusiastic, dynamic, and creative staff
- Providing a wide range of plastic films for packaging materials
- Being a close partner of many suppliers
Union Packaging is a reputable and experienced supplier of OPP, CPP, MCPP, PET, MPET, PE laminated film…. in the industry. We always try to research, develop and improve product quality, improve customer care ability to meet the increasing demands of the domestic and foreign packaging market. Please contact us now: 0987 437 469 – 0903 750 384 for specific advice and quotation.
UNION PACKAGING SOLUTION JOINT STOCK COMPANY
Address: No. 5, 3643A Street, Pham The Hien, Ward 7, District 8, HCMC
Tel: 0987 437 469 – 0903 750 384