Developments in Packaging Material (Part 01)

In comparison to the New Packaging Development articles I write, this article it is not a colourful or glamorous one, but all together the described packaging developments are very important as they will show us, packaging engineers, the recent developments in packaging material. No glamorous pictures but a serious discussion about the recent developments in material structures and the arising applications.
In one of my last articles I already wrote about the development of O-I Black Glass, today we will see:
1. a new water-based nano-composite coating for flexible packaging,
2. a new type of corrugated fluting – the R-Flute,
3. nano-coated ‘killer paper’ developed to extend food shelf life,
4. the first compostable water-based adhesive for compostable packaging materials,
5. a new dairy application for the PET blow moulding process.
That makes 5 items for today. I have 5 more for a next article.

Nano-composite coating to boost moisture barrier performance
Light-weighting, cost reduction as well as improved oxygen and moisture barrier performance, are the claims made by US-based InMat for its new water-based nano-composite coating for flexible packaging.
A one micron Nanolok WR 20135a coating will provide an oxygen barrier that performs more than fours times as effectively as PVDC coated PET at relative humidity from 0-80%. Its performance is almost twice as good at 85RH, the company states.

This coating will also provide a similar moisture barrier to that of PVDC coated PET when tested at 85RH and 40ºC. It has ~ 10x better oxygen barrier than EVOH (EVAL E) and 40 times better moisture barrier, according to InMat’s statement.

These barrier improvements over the RH range are potentially significant in maximising the performance of flexible packaging to preserve product quality and maintain shelf life. For example, meat and cheese packages have a high RH inside the package. Snack foods have a low RH inside, but are often stored in warehouses and trucks under high RH conditions.

The company said its technology allows it to combine water-dispersed polymers with nano-dispersed clays into stable water based barrier coatings. Its products are environmentally friendly as they contain no solvents or hazardous materials and are appropriate for food packaging applications. Furthermore the coating meets compostability standards on bio-based films and is compliant with all European and US food contact standards.

The Nanolok Technology can be applied via gravure coating processes to polyester film (or other substrates using appropriate adhesives). Once dry, a very thin coating (0.25-2 microns or 0.01-0.08mils) of Nanolok forms on the substrate.
This coating contains hundreds of nano-dispersed platelets per micron of coating thickness. These platelets form a tortuous path for molecules such as oxygen and aromatics, dramatically increasing the barrier properties of the substrate. The coatings are transparent, thus useful for see-through packaging applications.

R-Flute – ringing the changes in retail ready packaging
R-Flute is a new type of corrugated fluting developed by DS Smith Packaging. R-Flute’s calliper is 20% less than B-Flute’s, resulting in a profile in which the flutes are smaller and closer together than B-Flute, whilst optimising board strength. Compared with the widely used B-Flute, R-Flute offers a flatter, better surface for printing and presentation, a crucial advantage for more and more customers as they seek brand appeal and sales success with shoppers. In addition, the closeness of the flute tips helps perforated retail ready packaging to form squarely, open reliably and look good on shelf after opening.

SEM images showing general growth in silver nanoparticles sizes for a 100 mM silver nitrate concentration as a function of sonication time: (A) Uncoated paper, (B) 30 min sonication, (C) 60 min sonication, and (D) 120 min sonication. The scale bar in (A) and (B) corresponds to 2 μm, while in (C) and (D) it corresponds to 1 μm.

SEM images and particle size distribution of coated papers: (A) 25 mM/30 min, (B) 25 mM/60 min, (C) 100 mM/30 min, and (D) 100 mM/60 min. The particle size distribution was measured using the Scion Image software where n = 100. The scale bar in (A) and (B) corresponds to 100 nm, while in (C) and (D) it corresponds to 2 μm

FIB cross-sectional images of silver coated papers: (A1) Cross-sectional image of 25 mM/30 min coated paper; (A2) magnified image of the area marked as box in (A1). (B1) Cross-sectional image of 25 mM/60 min coated paper; (B2) magnified area from (B1). (C1) Cross-sectional image of 100 mM/60 min coated paper; (C2) magnified area from (C1). The scale bars in (A1) and (B1) are 500 nm, while that in (C1) is 400 nm

Nano-coated ‘killer paper’ extends food shelf life
Israeli scientists have said their new nano-coated “killer paper” could be used in food packaging to combat bacteria such as E.coli to extend product shelf life.
The team from the Institute of Nanotechnology and Advanced Materials of the Bar-Ilan University, claim in their study “Sonochemical Coating of Paper by Microbiocidal Silver Nanoparticles” that they have developed a “simple one-stop process” of coating paper with antimicrobial colloidal silver nano-particles using ultrasonic radiation.
The process developed at the Kanbar Laboratory of Nanomaterials involves the in-situ generation of nano-particles and their simultaneous application onto the paper substrate. The nano-materials were attached to the paper by a process of ultra-sonication – which the group said is “one of the most attractive methods for coating applications involving nano-materials”.
The silver nano-particles are anchored strongly to the surface either by physically embedding them in the surface or by forming chemical bonds or other interactions with the substrate to form a “remarkably sturdy coating”.
The coated paper showed potent antibacterial activity against food-borne disease-causing organisms such as E. coli and S. aureus, killing all of the bacteria in just three hours.

“Developing coated paper with antimicrobial properties of silver nano-particles could be an alternative to other food preservation methods employing radiation, heat treatment, low temperature storage, or the introduction of antimicrobial additives,” the researchers said.

The paper: “Coating of Paper by Microbiocidal Silver Nanoparticles” by Ronen Gottesman, Sourabh Shukla, Nina Perkas, Leonid A. Solovyov, Yeshayahu Nitzan, and Aharon Gedanken is published in Langmuir 2011, 27 (2), pp 720-726; DOI: 10.1021/la103401z.

Epotal Eco contributes to the development of biodegradable packaging materials
Biologically degradable adhesives will play a decisive role in the future when it comes to developing compostable packaging materials. Epotal  Eco from BASF is the first compostable water-based adhesive certified by TÜV, the German Technical Inspection Agency.

Epotal Eco is particularly suitable for the production of multi-layer films for flexible packaging materials based on biodegradable plastics. Possible applications are bags for potato chips or chocolate bar wrappings.

In just a few years, a gelatinous solution could be found where oil deposits lie today. The reason? The answer lies in an innovative and environmentally sound method that raises the recovery rate of the highly sought after raw material. When dissolved in water, a new biopolymer from BASF can be pumped into the earth and displace the oil which is deposited in sand and rock. The transparent, viscous solution is not produced by chemists in a test tube but by a fungus. The fungus is fed in a steel tank with, among other things, the starch building block glucose and oxygen. During the fermentation process it combines up to 25,000 glucose molecules into long chains. Once the chains are complete, the researchers separate them from the fungus. Oil companies can then inject the aqueous polymer solution into the borehole. The research project is financed by BASF subsidiary Wintershall to ensure that oil reserves that would otherwise remain permanently underground can be exploited in the future. Using white biotechnology to produce black gold? At BASF, we create chemistry. Photo: Courtesy BASF

According to the European EN 13432 standard, substances are considered fully biodegradable if at least 90% of the organic carbon contained in them is converted into CO2 within a testing period of no more than 180 days. The rotting test in composted earth showed that after only 70 days, 90% of Epotal Eco was broken down. The molecule structure of the product resembles the one of naturally occurring polymers. Microorganisms are able to convert them into carbon dioxide, water and biomass with the help of enzymes. The best results are achieved in industrial composting facilities since they offer ideal conditions for microorganisms. After the decomposition process, Epotal Eco leaves no toxic residuals and shows no negative impact on the environment.
Apart from its compostability, Epotal Eco offers all benefits of water-based adhesives, which are an environmentally friendly and efficient alternative to solvent-based and solvent-free products. They are free from toxic components and are suitable for food packaging. In addition, multi-layer films, which are produced with the help of water-based plastics, can be processed immediately.

New dairy application for PET container blow moulding process
To protect milk and specialty drinks against the UV rays which decrease shelf life, additives such as titanium dioxide [TiO2] are often added to high-density polyethylene or traditional PET containers. In addition to impacting the recycling stream, these additives are expensive, significantly increasing packaging costs.

Plastic packaging specialist Plastic Technologies claims that its oPTI process is particularly suitable for milk, drinkable yogurts and other specialty dairy products, and ideally-suited for companies with organic positioning which want package performance attributes without additives.
The oPTI technology provides a 100% PET bottle that, because of the introduction of foam, provides up to 50% opacity, thus protecting the product from the negative effects of light.
The technology is said to provide opacity without the use of additives that compromise the recyclability. In providing the opacity, the bottle is also light weighted by up to 6%.

The oPTI process is based on the MuCell technology licensed from Trexel. This microcellular foam injection technology moulds preforms which then can be blow-moulded on conventional equipment. The introduction of foaming occurs in the preform, so preforms can be centrally manufactured and distributed to blow moulders. The preforms are foamed in the injection process where a supercritical gas is blended into the polymer melt.

The bottles are made in four basic steps:
1. Nitrogen is injected into the melt through the barrel on a modified preform moulding machine to form a single-phase solution of polymer and gas.
2. Foam is produced as cavity-fill pressure is dropped below nucleation pressure during the injection cycle.
3. Foam cells expand as gas is diffused into bubbles. Processing conditions are used to control cell growth in the finished perform.
4. The preforms are then used on conventional, unmodified blow moulding machines to produce the final foamed bottles.
In addition to PET, the foam bottle technology is applicable to other resins such as polylactic acid (PLA) and polyethylene naphthalate (PEN). Potential applications include a wide range of bottles and jars in food, beverage, personal care, and household chemicals.

For improved container aesthetics, the process enables white or silvery foamed bottles to be made without additives which might limit package recycling. Decorations, such as embossed logos and art work, can be blow moulded prominently onto the containers, while it is said that the bottles have a unique surface feel and provide tactile traction which minimizes slipping.
Available in monolayer and over-moulded variations, while oxygen and CO2 barriers can be incorporated into the foam layer.

These are the first five material developments. For the next article I have:
1. Ready-to-use peel polymers offer resilience and easy opening,
2. New non-aluminium foil packaging for food and drink products,
3. Scientists create biodegradable Styrofoam from milk,
4. Amazing printing technique achieves stunning graphics on natural kraft paper,
5. Synthetic labelling adhesives for glass bottle labelling.

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