Feasibility Study on Degradable Plastics for Logistics Packaging
Chen Guo
School of management, Tianjin University of Technology, Tianjin 300382, China
Keywords:
Degradable Plastics, Green Logistics, Logistics Packaging.
Abstract:
In recent years, the booming development of caller has changed people's shopping way and consumption
concept. At the same time, it also leads to the rapid development of logistics express industry, but this
development also brings a lot of logistics packaging waste. Under the background of national vigorously
advocating carbon neutrality, green and recyclable logistics packaging has gradually become a requirement.
This paper introduces some degradable plastics that can be used in logistics packaging. This paper analyzes
the advantages and disadvantages of using biodegradable plastics in logistics packaging and tries to provide
corresponding countermeasure.
1 INTRODUCTION
Goods can participate in circulation through the
means of packaging, packaging is a necessary link
of logistics.
Packaging in logistics is also divided into three
types, one is the packaging of the goods just
produced, this packaging is generally considered to
protect and beautify the goods. The second is
outsourcing packaging, which generally considers
the wholesale problem. Most goods will be sold
more than one piece, requiring larger outer
packaging for packaging, which is common in the
food and beverage industry. Third, express
packaging, considering the related problems in
logistics transportation, need to add a layer of
express packaging, to ensure that goods will not be
damaged in logistics transportation, but also need to
meet the delivery, sorting, transportation, delivery
needs.
In 2020, China's express delivery volume
reached 83.36 billion pieces, up 31.2 percent year on
year, showing that China has become a global
Courier power. With the rapid development of
express delivery, the demand for packaging has also
increased dramatically. From January to July 2021, a
total of 15.01 billion pieces of postal delivery
services were delivered, up 1.3 percent year on year.
At this rate, express packaging material
consumption is expected to reach 41.27 million tons
in 2025.Recently, the National Development and
Reform Commission and the Ministry of Ecology
and Environment issued the "14th Five-year plan for
Plastic Pollution Control Action Plan", which has
clear requirements for express packaging,
e-commerce express should realize secondary
packaging, using recyclable packaging instead of
traditional packaging.
0
As a new type of green
material, degradable plastic has become a trend of
large-scale application in e-commerce logistics.
2 DEVELOPMENT PROSPECT
OF DEGRADABLE PLASTICS
A biodegradable plastic is a material that can
degrade thermodynamically and dynamically over a
period of time. There are two kinds of materials that
have been applied in logistics packaging on a large
scale, one is biodegradable plastic, mainly polylactic
acid (PLA), the other is petroleum degradable
plastic, also known as thermoplastic biodegradable
plastic, mainly polyladipic acid (PBAT). Polylactic
acid (PLA) is produced from renewable plants by
saccharification to convert it into glucose,
fermentation with related strains, and synthesis
through complex chemical processes. It can be
completely degraded and absorbed by some
microorganisms after use, producing carbon dioxide
and water that will not cause pollution. It has good
thermal stability, good solvent resistance, can be
processed in a variety of ways, such as extrusion,
spinning, biaxial stretching, injection blow molding.
In addition to having good biodegradability,
36
Guo, C.
Feasibility Study on Degradable Plastics for Logistics Packaging.
DOI: 10.5220/0011178300003443
In Proceedings of the 4th International Conference on Biomedical Engineering and Bioinformatics (ICBEB 2022), pages 36-40
ISBN: 978-989-758-595-1
Copyright
c
2022 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved
polylactic acid also has excellent glossiness,
transparency, hand feel and heat resistance. It is a
good green logistics packaging material. The current
global PLA production capacity exceeds 500,000
tons/year. NatureWorks is the world's largest
polylactic acid manufacturer with an annual
production capacity of 180,000 tons, accounting for
more than 30% of the world's polylactic acid
production capacity. The production of PLA is still
in the initial stage of development in China. Jiangsu
Yunyoucheng production line with annual output of
50,000 tons of PLA is the largest production line in
China. In recent years, new entrants have emerged in
the industry, mainly because of the promising
market prospects of lactic acid and its derivatives
lactide and polylactic acid in the field of
biodegradable new biological materials. Its
development has been successively included in
"863", "973", "Torch Plan", "13th Five-Year Plan",
"Made in China 2025" and "National Medium and
Long Term Science and Technology Development
Plan" key research projects.
0
The production process of polyglycolic acid is
synthesized by using adipic acid (AA), terephthalic
acid (PTA) and butanediol (BDO) as monomers
through esterification or transesterification and
polycondensation reaction in a certain proportion.
Direct esterification is a widely used production
process in China. The advantages of this method are
short process, high utilization rate of raw materials,
short reaction time and high production efficiency.
The disadvantage is that the reaction system is more
complex, the relative molecular weight distribution
is wide and difficult to control, the reaction
conditions are more demanding, the reaction
medium is more acidic, part of THE BOD
cyclodehydration reaction to form tetrahydrofuran
(THF), etc., which have influence on the product
quality. In addition, there are separate esterification
and series esterification processes, which have the
advantages of simple equipment, fewer intermediate
substances in the reaction system, narrow
distribution of relative molecular weight, easy
regulation of product viscosity, and reuse of waste
products. The disadvantage is that the product
quality may vary from batch to batch. Direct
esterification is a widely used production process in
China, which has high fracture elongation and
toughness, and excellent physical and chemical
properties. PBAT biodegradation mainly depends on
its chemical structure and degradation of the
environment, almost completely biodegradable,
some by microbial fermentation is degraded in
nature, some can make through chemical hydrolysis
and thermal degradation of polymer chain break in
depolymerization, there are also some
depolymerization intermediates by microbial
metabolism.
In recent years, China has issued a series of
policies to encourage the application and promotion
of biodegradable plastics, which has led to the
continuous expansion of the market for
biodegradable plastics in China. At present, China
has become a major producer of biodegradable
plastics in the world, and its products are exported
abroad, mainly to Europe and North America. It is
expected that with the growing demand of the global
degradable plastics market, the export and domestic
market size of Degradable plastics in China will
continue to increase. In 2020, the annual production
capacity of China's PBAT and PLA will be about
300,000 tons and 100,000 tons respectively.
According to industry estimates, by 2025, the
demand for degradable plastics in express
packaging, disposable plastic tableware, plastic
shopping bags and agricultural mulches will form a
total market space of about 2.5 million tons.
Accounted for in addition to the two bigger
biodegradable plastics, such as starch composite
plastic, poly (butyl diacid butyl glycol ester (PBS)
and poly hydroxy fatty acid ester (PHA) such other
accounts for the relatively small size of the market
of biodegradable plastics, through the model
forecast, can be expected to 2025 biodegradable
plastic future market demand will reach 3.3 million
tons, as shown in figure1.It is clear that
biodegradable plastics have a promising future.
Figure 1: Forecast of future market demand release
rhythm of degradable plastics (10k tons).
Feasibility Study on Degradable Plastics for Logistics Packaging
37
Figure 2: Comparative analysis of comprehensive performance of PLA, PBAT and LDPE
3 COMPREHENSIVE
COMPARISON BETWEEN
DEGRADABLE PLASTICS AND
TRADITIONAL PLASTIC
PACKAGING
Polyethylene (PE) is a widely used traditional
plastic, ethylene by polymerization of a
thermoplastic resin, is one of the most common
plastics, the annual production of more than 100
million tons of polyethylene resin, accounting for
34% of the total plastic market.PE is a typical
crystalline polymer with a melting point of 130℃ ~
145℃. It is characterized by tasteless, odorless,
non-toxic, matte surface and milky waxy particles. It
is also a major alternative to biodegradable
plastics.PE has excellent crystallinity, water vapor
barrier and weather resistance, which can be
collectively referred to as "PE characteristics". In
fact, currently common biodegradable plastics are
aliphatic polyesters, such as PLA and PBS, which
can be roughly regarded as PE containing ester
bonds. The ester bonds in its molecular chain give it
biodegradability, and the aliphatic chain gives it "PE
properties". Promising biodegradable plastics need
to be both biodegradable and "PE". Therefore, it is
necessary to compare the comprehensive properties
of biodegradable plastics and polyethylene.
As shown in the figure 2, PLA and PBAT have
different performance from PE. Each has its own
advantages and disadvantages, but none of them
fully possess the "PE characteristics". PBAT and
mechanical properties and the melting point of PE, it
can cover the basic PE in disposable products
industry, the application of PLA and intensity is
higher than the melting point of PE, but with
significantly lower tensile toughness and crystalline,
polymer relative molecular weight distribution of
the products is too wide, PLA itself for the linear
polymer, it makes the strength of the PLA material
often cannot meet the requirements, High
brittleness, low thermal deformation temperature
(54℃ under 0146MPa load), poor impact resistance,
only when it is toughened, crystallization promotion
and other modification can basically cover PE in the
disposable products industry application. In addition
to the basic characteristics of biodegradable plastics,
PLA also has its own unique characteristics.
Traditional biodegradable plastics are not as strong,
transparent and resistant to climate change as
ordinary PE.PLA has similar basic physical
properties to petrochemical synthetic plastics, which
means that it can be used to manufacture a wide
range of applications. PLA also has good gloss and
transparency, comparable to films made from
polystyrene, which cannot be provided by other
biodegradable products. PLA film has good air
permeability, oxygen permeability and
dioxide-carbon permeability. It also has the
characteristics of odor isolation. When PLA is
incinerated, its combustion heat value is the same as
that of incinerated paper, which is half of that of
traditional plastics (such as polyethylene), and the
incineration of PLA absolutely does not release toxic
gases such as nitrogen compounds and sulfides. The
body also contains lactic acid as a monomer,
indicating the safety of the breakdown product.
According to the analysis, theoretically, PLA and
PBAT can replace all disposable plastics. In
addition, although PLA and PBAT have overlapping
application fields, they have different characteristics.
For example, PLA belongs to hard plastics, while
PBAT belongs to soft plastics, which can be
approximately regarded as polypropylene and
polyethylene in petrochemical products. Moreover,
PLA membrane bags with poor blowing
processability are mostly blended with PBAT with
good toughness, which can improve the blowing
processability without damaging its
biodegradability.
4 EXISTING PROBLEMS AND
IMPROVEMENT MEASURES
OF DEGRADABLE PLASTIC
PACKAGING
Although biodegradable plastic packaging has a
promising development prospect, it is difficult to be
applied on a large scale in real life. The existing
reasons are three, one is that the development of
degradable plastic is not mature enough, a large part
of the main body involved in logistics is difficult to
product melting point/°C tensile strength /Mpa Elongation/％ Degradation rate Water vapor barrier Oxygen barrier
PLA 180 40-60 4-10 fast Average Average
PBAT 120 18 750 fast Poor Poor
LDPE 110 148 148 Non degradable Good Poor
ICBEB 2022 - The International Conference on Biomedical Engineering and Bioinformatics
38
accept this kind of emerging products. The solution
should be for the government to raise people's
awareness of environmental protection and change
people's view of degradable plastics through
relevant policies or publicity. The second reason is
the low bearing capacity of degradable plastic bags,
which to a large extent cannot meet the requirements
of logistics for multiple loading and repeated use.
The third and most important point is the cost factor.
Enterprises generally take maximizing profits as the
premise. According to relevant data, the price of
PLA and PBAT is 3-4 times that of mainstream
plastic PE, so using degradable plastic packaging
will compress the profit of logistics enterprises on
the premise of maximizing profits. If this kind of
excess expenditure is added to the logistics
demander, it may lead to the decline of the
competitiveness of similar products in the market.
Nowadays, the effective way to improve these two
reasons is to blend and modify them to improve their
physical and chemical properties and reduce the cost
of materials. Using other materials with lower cost
to blend and modify them can effectively reduce the
production cost of degradable plastics.
Several common blend modification, such as the
blend modification of PBAT and PLA, PBAT has
low tensile strength and modulus. PLA has the
characteristics of high strength and high modulus.
However, due to its inherent brittleness, low
elongation at break, low impact strength and easy
bending deformation, PBAT and PLA are blended.
The toughness of the material is improved while
maintaining its degradability. It solves the problem
of packaging damage caused by insufficient
hardness in logistics packaging.
0
PBAT can and
starch blend modification of polymer materials,
starch sources, cheap, can be completely
biodegradable, but its itself does not have
thermoplastic, and easy bibulous, not easy
processing, will join the rest of the PBAT matrix
modified starch, can greatly reduce cost and
accelerate the degradation rate of PBAT, to reduce
cost and solve the problem of resource shortage and
environment pollution. PBAT can also be filled and
modified with inorganic CaCO3. Nano CaCO3 has
the characteristics of small particle size and high
activity, and has a strong interface binding force
with the polymer.
0
It is usually used as a filler in
different polymers. Therefore, adding it into PBAT
to prepare degradable composite materials can
improve the performance of PBAT and greatly
reduce the cost.
For the production of biodegradable plastics
producers, there are a lot of technical barriers, PLA
exist two kinds of preparation methods, one is the
lactide ring-opening polymerization and direct
polycondensation method, the lactide ring-opening
polymerization is of the methods used by the
majority of enterprises, and this method the required
conditions are harsh, many domestic enterprises
subject to the technical level and production scale,
etc. There is no way to expand further. Another
reason is the lack of strong policy or legal support.
In foreign countries, the government set up a special
development fund, tax incentives and other policy
support the development of biodegradable plastics
industry, at present China in this respect, the support
to strengthen gradually, macroscopic policy support
more and more, although issued the "difference"
plastic pollution administrative action ", but the lack
of detailed rules, against the development of
production-oriented enterprises. Insufficient funds
and financing difficulties of enterprises. The scale of
Chinese biodegradable plastics enterprises is not
large enough, and the return cycle of biodegradable
plastics industry exceeds the expected design,
resulting in insufficient funds and financing
difficulties for enterprises. The evaluation system is
not perfect. Biodegradable plastics is a new industry,
many materials and products developed, there is no
product standards, to trade a lot of inconvenience
and disputes. Therefore, countries should be legally
clear biodegradable plastics in modern circular
economy system, the status and importance to give
strong support on policy, on the application and
development of biodegradable plastic products
subsidy policy, refine on tax preferential measures,
and to set up special national development fund,
lead into the various funds, to promote the
development of degradable plastics industry.
Relevant government departments assist enterprises
and scientific research institutions in technological
innovation and promote the research, development
and popularization of mature technologies; Actively
develop cheap and widely sourced raw materials,
using mature technology and processing processes;
In order to reduce the production cost, it is necessary
to find efficient strains and low-cost media, develop
the best fermentation process and molding process
equipment. Strengthen investment in biodegradable
plastics standards, testing technology and other
aspects, improve product standards.
Feasibility Study on Degradable Plastics for Logistics Packaging
39
Figure 3: An illustration of a fully biodegradable plastic
bag.
5 CONCLUSION
As policies continue to increase, it has gradually
become a requirement that biodegradable plastics
replace traditional plastics as logistics packaging.
Relying on its environmental protection, energy
saving, recyclability and other properties,
biodegradable packaging perfectly conforms to
modern people's green and environmental ideology,
and also conforms to my country's sustainable
development strategy, and its future market is very
broad. Although the development of degradable
plastics is not yet mature enough, and related
technologies are not fully mastered, as the global
demand for degradable plastics continues to expand,
the degradable plastics industry will be forced to
further develop and improve. The emergence of
degradable packaging materials not only conforms
to the development theme of green and
environmental protection, but is also a new trend in
the development of logistics packaging materials,
and also has a profound impact on green logistics.
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