Films|Flexibles|Bags
Films|Flexibles|Bags Multilayer made from Bio-Flex F 2110 / A 4100 CL / F 2110 Multilayer made from Bio-Flex A 4100 CL / Bio-Flex F 2110 / Bio-Flex A 4100 CL for deep freeze applications Opportunities through new Bio-Flex grades The combination of organically grown food with packaging made from sustainable bioplastics is a logical step and completes the overall sustainable message while providing consumers with the positive feeling of contributing to an ecofriendly environment. Compared to conventional plastics, bioplastics offer an alternative ‘end-of-life’ option. The ability to use bioplastics after their useful life in composting facilities or energy recovery systems are important factors. In particular, renewable plastics can contribute to the efficient utilization and conservation of our resources in terms of ‘renewble energy‘. The following practical examples will prove the expansion of the range of applications for bioplastics by means of efficient utilisation in multilayer systems. For both examples, the high content of natural resources (provided by Bio-Flex A 4100 CL) as well as the excellent strength and flexibility (provided by Bio-Flex F 2110) were the decisive factors for choosing a multilayer system made from Bio-Flex. • McCain uses a three layer combination made from Bio- Flex A 4100 CL / Bio-Flex F 2110 / Bio-Flex A 4100 CL for packaging of their ‘Bio-Ernte’ product line. This multilayer allows for the production of a very flexible and extensible film with a great stiffness also at low temperatures. (deep freeze) • A three layer system made from Bio-Flex F 2110 / Bio- Flex A 4100 CL / Bio-Flex F 2110 was used by Umbra Olii for wrapping their ‘Ecolive’ laundry soap, which is made from 100% natural olive. The film allows for a very appealing glossy surface along with a great toughness and chemical resistance as well as good barrier properties for a bioplastic. • One of the leading producers of napkins uses a three layer film made from Bio-Flex A 4100 CL / Bio-Flex F 2110 / Bio- Flex A 4100 CL for their compostable product line. Metallization as a possible solution to increase barrier The lower barrier of many bioplastics against water and oxygen, when compared to conventional plastics, can be improved by coating techniques such as metallization. Chart 3 shows the improved barrier of a metallized Bio-Flex co-ex structure. Most notably, the oxygen barrier is highly improved which makes these films suitable for new applications in food packaging. Usually the layer thickness in metallization processes is below 0.1 µm. Therefore compostability/ biodegradability of the final film structure can still be achieved. u Chart 3: Transmission rates of Bio-Flex films in comparison to other plastics (WVTR = Water Vapour Transmission Rate) 350,0 WVTR [g / (m 2 · d)] 300,0 250,0 200,0 150,0 100,0 50,0 0 PLA Bio-Flex A 4100 CL / F 2201 CL / A 4100 CL Bio-Flex F 2201 CL Bio-Flex A 4100 CL Testing conditions (25 µm film): H 2 O: 23°C / 100% hum. O 2 : 23°C / 0% hum. Metallized Bio-Flex A 4100 CL / F 2201 CL / A 4100 CL PET | | | | | | | 250,0 500,0 750,0 1000,0 1250,0 1500,0 1750,0 Oxygen [cm 3 / (m 2 · d)] PP 16 bioplastics MAGAZINE [06/11] Vol. 6
Films|Flexibles|Bags Multilayer made from Bio-Flex A 4100 CL / F 2201 CL / A 4100 CL (In-House) Recycling of compostable multi-layer structures made from Bio-Flex To achieve an overall sustainable and cost effective multilayer product it is also necessary to recycle the production scrap (e.g. edge trims) and to use the regrinds in the middle layer of the film. Various Bio- Flex resins used in the layers could have an effect on the mechanical properties and optical appearance of the middle layer. Analysis have been done using the multilayer structure Bio-Flex A 4100 CL / F 2201 CL / A 4100 CL (with layer ratios 20 % / 60 % / 20 %) as this is the most commonly used structure containing multiple Bio-Flex types. As the production scrap will be added into the middle layer all of the trials carried out are only reflected upon this middle layer. It is assumed that as a maximum 20 % of production scrap will be used in this middle layer. Degradation of the biopolymers during the different production steps normally implies a higher melt flow and softer end product. Comparing the results of these trials it is shown that the amount of Bio-Flex A 4100 CL in the regrind compensates the negative effects of possible mechanical degradation. The results of the tensile test indicate a shifting of the properties in transversal direction (TD) and machine direction (MD), the tensile test results increase by 5% measuring in TD but decrease by 10 % in MD. The optical appearance of the film is still the same, as a reduction of the transparence and a decrease of the haze is not visible. Although the results of all tests have shown that the usage of regrind will not affect the properties negatively, it is recommended to processors to conduct own tests. Since the shear during production and recycling has a high influence on the material these results can vary and should be tested and reviewed independently. • Chart 4: Tensile Modulus of Bio-Flex mono layer, multilayer and recycled films Modulus of elasticity MD [MPa] 1000 750 500 250 0 www.fkur.com Bio-Flex A 4100 CL / F 2201 CL / A 4100 CL (20 / 60 / 20 [%], 20µm) | | | | 250 500 750 1000 Modulus of elasticity TD [MPa] Chart 5: Elongation at Break of Bio-Flex mono layer, multilayer and recycled films Modulus at break MD [MPa] 400 300 200 100 0 Bio-Flex F 2201 CL + Recyclat Bio-Flex A 4100 CL / F 2201 CL / A 4100 CL (20 / 60 / 20 [%], 20µm) Elongation at break TD [MPa] Bio-Flex F 2201 CL + Recyclat Bio-Flex F 2201 CL Bio-Flex F 2201 CL | | | | | | | 50 100 150 200 250 300 350 bioplastics MAGAZINE [06/11] Vol. 6 17
