Why Clarified PP?
Clarity in Polypropylene is achieved by incorporation of small quantity of Ethylene during polymerization. This product is called PP Random Copolymer. In PP Random copolymer chain regularity is disturbed, with decrease in crystallinity and rate of crystallization which restrict the size of crystalline aggregates resulting in better clarity. Use of Clarifier/Nucleating agent further enhances the clarity. In Clarified PP, large number of crystallites is smaller in size than the wavelength of light. Nucleation gives better clarity and high stiffness.
(Fig 1: Mechanism of Clarified PP; courtesy Milliken Chemicals)
Products manufactured from Clarified PP possesses:
• Glass like transparency
• Excellent moisture barrier & Chemical resistance
• Higher continuous use ambient temperature
• Hot fillability ( upto 98°C)
• Product can be retortable & microwavable
• Excellent balance of stiffness, flexibility and hinge property coupled with excellent Environment Stress Cracking Resistance (ESCR) property
• Cost effective value proposition
Versatility of Clarified PP:
Clarified PP having excellent process friendliness. It can be processed with equal ease for standard Injection Moulding, Thin Wall Injection Moulding (TWIM), Injection Stretch Blow Moulding (ISBM) applications. The chart given below an insight in technology drives for Clarified PP.
Region wise demand of Clarified PP:
Clarified PP, contributing to 7.5% share, which is highest amongst all types of PP. With present global consumption of about 3.5 mln tpa, the demand is likely to grow further. Presently Asia Pacific, Western Europe and North America are the major Clarified PP users. Asia Pacific region will be witnessing highest Clarified PP demand growth (1.3 mln tpa in 2010). In coming years, India has to catch up the global trend from current 4% share to 7.5% as per world Clarified PP consumption.
Growing Technology base for PP:
At present Injection Stretch Blow Moulding (ISBM) and Thin Wall Moulding (TWIM) are in its early stages of development in India. Injection Moulding and Thermoforming sector is in a mature stage and still growing at the rate of 10-20 % annum. ISBM & TWIM are the technologies which will be high growth in future and they will become the technologies for the coming years due to their capabilities of mass production, with accurate & precision products.
Property comparison of Clarified PP with other polymers:
Compared to other materials used as packaging container or bottles, PP has many advantages including its light weight, moisture barrier, toughness, strength, cost effectiveness and recycle-ability.
Table 1: Property comparison Of Clarified PP with other Polymers
Beverages Classification: As can be seen from Table 1, Clarified PP has excellent clarity and hot fillability but has poor oxygen barrier. Therefore it can be safely used for Dairy beverages, low concentration fruit juice, but cannot be used for carbonated drinks, beer and soft drinks.
(Fig 4: Beverages classification based on fillability & O2 sensitivity; courtesy Millken Chemicals)
Growth Avenues for Clarified Polypropylene:
* Flavoured Milk in Clarified Polypropylene: Processed food in India is a sun rise industry. With the back-up from union & local governments combined with the demand pull created by the organized Retail industry and changing food habits of middle class families, this sector is experiencing unprecedented growth. This in turn is creating lot of opportunities in the packaging of these products. In Milk Beverage industry, Flavored Milk is one such value added product growing annually at 20%. Flavoured Milk comprises of skimmed or semi- skimmed milk and contains less than 3 % fat.
* Flavoured Milk Industry Snapshots:
• Market Value: Rs. 250 Cr.
• Over 80 Dairies across India with capacity of 300 KL / Day ; Growing @ 25 %
• Amul - leader in the market with 72 % market share
• Other players in the market: Mother Dairy, Aavin, Nestle, Cavin Kare
• Products are available in Glass bottles, Cartons, Sachets
• Pack size: 100/200 ml
Major Flavoured Milk Brands in India: Amul, Mother Dairy, Britannia
Packaging Technology for Flavoured Milk: Flavored milk is available in crown cork glass bottles, Glass bottles with aluminum foil lid or snap – on plastic lid, plastic sachets and aseptic packs (Tetra bricks). Flavoured milk is subjected to sterilization / retorting which effectively kills or eliminates transmissible agents (such as fungi, bacteria, viruses, and spore forms etc.) Sterilized product has a shelf life of more than 6 months at ambient temperature.
Conventionally Glass Bottles are used for sterilized products such Flavoured Milk. The autoclaves used for Sterilization of Glass Bottles are very simple needing no process automation. These are typically steam Sterilizers where the required sterilization temperature (1210°C) is achieved by pressurizing the steam up to 30 psi (2.2 Bar). The temperature is maintained by maintaining the steam pressure. However the same sterilization conditions cannot be used for Plastic Bottles. For Clarified PP, constant Temperature – Pressure relationship in these systems results in Containers collapsing or bursting during the process. This problem is overcome by the use of Super Heated Water Spray Sterilizers (SWHS)
Working Principle: Heating and cooling is done with circulating water in a closed system. The water gets heated by passing through the exchanger, which is then sprayed on the product through the nozzles from the upper part of the chamber. High water flow rated also ensures that uniform temperature distribution is maintained throughout the chamber during the sterilization phase. During the cooling phase, the heat exchanger is fed with cooling medium and the circulating water gets cooled, which in turn is sprayed onto the product, thus reducing its temperature to the desired level. A sterile air overpressure is maintained during all the phases to compensate the internal pressure build up within Bottle/Container, thus no bottle deformation takes place.
Schematic Representation of Working of – SWHS
(Fig 5: Effect of pressure compensation on plastic bottles (Internal pressure Vs ambient))
Internal bottle pressure = External Pressure on Bottle in Sterilizer
Result: No Deformation during Sterilization
Clarified PP can withstand sterilization temperature (under proper conditions and container design) & Hot fillability (up to 98°C) in addition to the Contact Clarity. This makes Clarified PP the most preferred plastic material over other plastics.
Replacing glass to Clarified PP (200 ml bottle weighing total weight of 14 gms) resulted into: Bottles made of Clarified PP using Injection Stretch Blow moulding and Caps by Injection moulding process.
o Material conservation: Proposed Clarified PP - 200 ml bottles are 85% lesser in weight to carry 200 ml than glass
o Reduction in transportation: Lighter packaging can mean lighter loads or fewer trucks are needed to ship the same amount of product, helping to reduce transportation energy, saving of fuel.
o Waste reduction: Weight- reduced packaging also helps to reduce the amount of waste generated.
Shift to Clarified Polypropylene bottles can result in substantial saving to Dairies across the country.
Other Clarified Polypropylene applications
Food & Health Drink Sector: India is world’s second largest producer of food, second to China. Indian Food Industry is US$75 bln, out of which almost 65% in un-organized sector. Considering the growth of economy and changing lifestyle branded items market will grow and trend of new variants in existing range with stylish packaging. Beverages can be classified as Dairy products, water where cold filling is generally required. Hot filling beverages include flavoured water, Sports drinks etc. Oxygen sensitive beverages comprise of CSD drinks, beer and long shelf life juices as mentioned in above graph.
Water, Fruit juice and Beverages market is growing. Government of India is giving incentives to boost investment in Food Processing Industry.
Healthcare Sector: Presently Indian Pharma industry is US$4 bln Industry with capital investment of US$0.5 bln and growing at over 20% pa. India is one of the top 5 manufacturers of bulk drugs and amongst top 20 exporters of pharmaceutical products. India is becoming global sourcing base and contract manufacturing with focus on innovative packaging/disposable medical devices. Indian companies are tapping international generic market by setting up subsidiaries.
Medical Disposables: Medical disposables are single use products, mainly PP non woven based used for applications like mask, caps, gown & bedsheets etc.
IV fluid bottles: There are mostly blow moulded PP bottles made by EBM/ISBM process sterilized at 120°C for 20 minutes.
Thin Wall Injection moulded Containers: Variety of Injection Moulded and thin wall containers are employed for numerous household applications like containers for dairy products, Snacks packaging, Disposables cups for soft beverages & drink, Microwave containers for RTE food, Confectionery boxes, storage boxes etc. Clarified Polypropylene is a versatile polymer with excellent combination of clarity, hot fillability that has immense growth potential for packaging of food beverages. It can revolutionize packaging of Dairy, Food & Health drink, and medical products with number of applications. Growth can be captured by employing proper strategy and partnership/ associations with entire value chain. Broadly it should cover-
a) Facilitate capacity creation by downstream development
b) Introduction of state – of – art machines for high volumes
c) Partnership with key end users and nodal agencies (GCMMF, Coke, CFTRI)
d) Creating awareness for clarified PP penetration through customer relationship programs (CRMs)
(Source Courtsey: Dr. U.K.Saroop, Business Development-Polymers, Reliance Industries Ltd)