Techniques and QC of Chyau Long Machinery Company

Chyau Long Machinery Company

P	roduct Category

Recycling Equipment

Pulverizer

Pelletizer

Conveying System

Continuous Mixer

Embossing Machine

Kneader

Mixer Equipment

Vertical Mixer

Extruder

Techniques and QC

Home > Techniques and QC

Kiwi Plastic Co. Ltd., We introduce you to Biodegradable Bags and the environment.:

Introduction to Biodegradable Plastic Bags
The time has come to consider our everyday usage of plastic bags, your supermarket checkout bags and the rubbish bags which are being discarded in the landfill.
With today’s technology, these bags can be made to biodegrade when discarded into a landfill or rubbish tip.

How does this work?
During the manufacturing of plastic bags, harmless additives are added to the plastic resins which will cause these plastic bags to break down and eventually biodegrade when discarded into the landfill. This process is called biodegradation.
These additives are harmless to the environment but will cause the plastic bags to biodegrade when discarded into the landfill.

How long will it take to biodegrade?
Once discarded into the landfill, the dwell time will normally take between 4 to 6 months. From then on rapid micro-fragmentation will take place and finally these plastic bags will change into carbon-dioxide and water, which is good for the plants and trees around the landfills.

How will these biodegradable plastic bags properties be affected?
The strength, texture and functions will be the same as the ordinary plastic bags. The plastic bags will start to biodegrade when discarded into the landfills where, moisture, heat, light and bacteria are present in these surroundings.
Moisture, heat, light and bacteria are the conditions required in order for the discarded plastic bags to react and biodegrade. Finally, the residue will be only water and carbon-dioxide.
However, in order to maintain the strength of these plastic bags, it is recommended that they are keep in a dry and away from sunlight during storage.
For more information please contact Kiwi Plastic Co Ltd on their toll free 0800 2bagit (0800 222448) for New Zealand and 0064 4 2377829 for International enquiry.

PRIVATE & CONFIDENTIAL Technical Report BD 56

1. Background
Kiwi Plastic (New Zealand) are interested in using Wells’“Reverte”biodegradable master batches in selected packaging film applications.
We have recommended BD 92845 for their potential application(s). This is a hybrid formulation containing a mixture of a metal ion pro-oxidant system and a micronised cellulosic biodegradation initiator.
It is suitable for inclusion in both high density (HDPE) and low density polyethylene (HDPE).
Kiwi Plastic have produced bags containing various amounts of Reverte BD 92845 and have submitted them for an evaluation of their biodegradable properties.

2. Method
Oxo-degradation of polymer chains results in the formation of a carbonyl group at the point of scission. The chain scission (degradation) of the polymer chain causes a serial reduction in polymer molecular weight which ultimately results in acute embrittlement, micro fragmentation and biodigestion.
Measurement of the onset and level of carbonyl group development in the test film is a direct measure of the induced degradation of the film by the metal ion pro-degradant.

2. Method (Cont’d)
Polyethylene films are reduced to an embrittled state when the carbonyl index is greater than approximately 0.33.
The film samples were produced containing 1%, 3% and 5% of BD 92845 in Both LDPE and HDPE. These samples were aged in a UV ageing cabinet with UVA and UVB Lamps to simulate outdoor sunlight. The temperature of the cabinet was maintained at 50℃.
Samples were removed after fixed time periods and the carbonyl index determined by Infra-red analysis. In addition the films were empirically assessed for friability and state of embrittlement.

3. Results
Samples were aged according to the aforementioned procedures and the carbonyl indices determined.
The results were as follows:

3.1 Carbonyl Indices and Empirical Observations

Exposure time(weeks)	0	1	2	3	4
LDPE Control	0.020	0.020	0.030	0.040	0.060
1% BD 92845 in LDPE	0.049	0.053	0.110	0.250	0.420*
3% BD 92845 in LDPE	0.055	0.071	0.150	0.375*	0.637≠
5% BD 92845 in LDPE	0.048	0.080	0.173	0.580*	0.990
HDPE Control	0.020	0.020	0.030	0.040	0.050
1% BD 92845 in HDPE	0.030	0.040	0.123	0.210	0.380*
3% BD 92845 in HDPE	0.051	0.033	0.088	0.320*	0.550≠
5% BD 92845 in HDPE	0.055	0.058	0.130	0.520*≠	0.990≠

3.2 Degradation graph

Techniques and QC

4. Discussion of results
It can be seen that the control samples of PE film demonstrated fairly typical behaviour, not reaching a point of embrittlement during the test period and only reaching a minimal level of oxidation as demonstrated by the carbonyl indices of only 0.05 for the HDPE and 0.06 for the LDPE achieved after the 4weeks ageing period.
In contrast to this , all of the specimens containing BD 92845Have demonstrated a highly enhanced rate of decomposition, reaching a state of embrittlement in the test chamber between 2.5 and 3.75 weeks of ageing.
Whilst all samples exhibited degradation to embrittlement and microfragmentation during the test period, the rate of degradation was affected by the addition level of the additive, with the higher addition levels giving faster rates of degradation.

4. Discussion of results (cont’d)
It is difficult to quantify this in terms of real-time degradation due to the vagaries of natural conditions, but applying Arrhenius principles to these accelerated ageing results would suggest that ageing for 12 hour days at a constant temperature of 25℃ in sunlight would result in the following performances:
1. 1% addition of BD 92845 in LDPE- a dwell time of around 4 months followed by degradation to embrittlement in a further 6 to 8 months.
2. 3% addition of BD 92845 in LDPE- a dwell time of around 4 to 5 months followed by degradation to embrittlement in a further 4 to 6 months.
3. 5% addition of BD 92845 in LDPE- a dwell time of around 5 months followed by degradation to embrittlement in a further 2 to 3 months.
4. 1% addition of BD 92845 in HDPE- a dwell time of around 4 to 5 months followed by degradation to embrittlement in a further 6 to 7 months.
5. 3% addition of BD 92845 in HDPE- a dwell time of around 5 months followed by degradation to embrittlement in a further 4 to 6 months.
6. 5% addition of BD 92845 in HDPE- a dwell time of around 5 to 6 months followed by degradation to embrittlement in a further 2 to 3 months.
These extrapolated results have been prepared in good faith, but any potential user would have to carry out his own empirical observations to ensure that the product was fit tor his purpose in the precise ageing regime employed.

5. Conclusion
The addition of Reverte BD 92845 has been shown to be very effective in introducing a biodegradable characteristic to both high density and low density polyethylene films and the degradation profile can be adjusted through variation of addition rate.

Certificate of Conformity Food-Contact Plastics

A Sample of LDPE film containing 5% BD 92845 supplied by Wells Plastics Ltd Stone, Staffordshire, UK has been tested by Rapra Technology Ltd. to the requirements of EC Directive 2002/72/EC“Plastics Materials and articles in contact with food”. Test conditions employed were 10 days at 40℃ with aqueous and fatty food simulants. The composition of BD 92845 was declared to Rapra in confidence. All additives are approved for food contact use.
Results obtained, reported in Rapra CTR Number 44997 have demonstrated that the material complies with the extraction requirements of the Directive. Levels of migration are within the prescribed limits. Therefore, the material can safely be used with all food types at temperatures<40℃.
Rapra Technology Ltd analytical laboratories are accredited by the United Kingdom. Acreditation Service (UKAS) as meeting the requirements of ISO17025. Food Contact Migration Testing to EC requirements is included in the list of accredited tests.

TOP