FAQs

FAQ

FREQUENTLY ASKED QUESTIONS

How to dry PLA?

REVODE101 has been processed by drying crystallization, after which, the highest heat stability of the resin is 110 ℃, and the moisture content is less than 200 ppm. The resin that stored in Aluminum foil bag, protected by box or bag outside can be used directly. Re-drying of the resin can make the moisture content lower than 100 ppm, which is favorable to enhance the processability of the resin and the quality of the sheet.
When re-drying the resin, the un-dehumidified hot air is forbidden, for without dehumidifier, not only the drying effect cannot be obtained, but also the speed of water absorbance of PLA resin can be accelerated. The dehumidified air can guarantee the drying effect of PLA resin in desiccator.
Suggested PLA drying conditions are shown in the following table:

Drying Parameter Typical Settings
Residence Timehours 2-3
Air Temperature℃) 90
Air Dew Point℃) -40~-42
Air Flow Ratem3/hr-kg resin 1.85
How to renew PLA resin?

Renewable materials can be reused (the renewable materials should be not longer than 3 months, and not more than 35% in complex).  Owing to the demand that the moisture content of sheet extrusion should be lower than 200 ppm, the renewable materials must be dealt with crystallization and high-temperature drying by desiccant device.
Crystallization method 1:
General crystallization equipment for PET is acceptable. For example, when 0.5 m3 crystallization autoclave is selected, the materials should be mixed homogeneously, with a 1:1 weight ratio of renewable materials to pure PLA. After being added into the crystallization autoclave, the warming crystallization of complex started under mixing at a speed of 3 rpm. The temperature is set at 60℃ for 20min, 80℃ for 10 min, 95℃ for 10min, at last at 110℃ for 30 min, and then lowing temperature step by step. The whole crystallization process lasts for about 1.5 hour.
Crystallization method 2:
By using the Kreyenborg infrared crystallization equipment, the materials are heated by infrared, accompanied by rotation mixing after being added into the infrared crystallization rolling barrel. The merit of this method is that the crystallization and drying process are carried out at the same time, and the process can be ended within 15~20 min.
Crystallization method 3:
After being pre-dried at low-temperature, the renewable materials will be extruded and palletized, after then, the crystallization process can be done in PET crystallization equipment.

Note: Bits and pieces can be reused for several times. During the reuse process of renewable materials, a small amount of assistant agent – ADR can be added to reduce the properties decline of renewable materials effectively, and the recommended amount is 0.1~0.6%.

 

The egradation specification of PLA

Compost degradation
The PLA can achieve full biodegradation within 180 days under compost degradation conditions, and the final products are carbon dioxide and water. The composting conditions are as follows:
○ Temperature is 58±2°C
○ Humidity is 98%
○ There are certain microorganisms

Landfill degradation
The landfill conditions are different from the composting conditions. Therefore, the degradation rate of PLA degradation is slow, generally takes 2-5 years, but the degradation products do not pollute the groundwater without destroying the plant growth, and not waste the cultivated land, and eventually it is still fully degraded.

Incineration
The combustion value of PLA is small, and the complete combustion products are carbon dioxide and water, which do not pollute the air.

What is PLA resin?

PLA takes annually renewable resources – corn, cassava and other plants as raw material. After fermentation by microorganisms, lactic acid will be extracted, then PLA will be produced through a process of refining, dehydration polymerization, high temperature pyrolysis and final polymerization. PLA has excellent biodegradable property. After disposal, within one year, it can be degraded into carbon dioxide and water by microorganisms in the soil, and do no harm to our environment. PLA is a kind of aliphatic polyester with basic characteristics of general micromolecule materials. PLA has good machanical properties, low shrinkage, and is competent to the application of most synthetic plastics, also it's widely used in the production of package materials, disposable tableware, household electrical appliance shell, fiber, 3D supplies etc.

Because PLA derives from renewable plant resoures but not the petroleum-based traditional plastics, so it can truely realize energy-saving and enviromental protection, and PLA is considered to be the most promising new "ecological material".

Performance indicator reference

ITEM

UNIT

REFERENCE INDEX

Appearance

White or yellow cylindrical granules

Particle Diameter

mm

2~4

Density

g/cm3

1.25±0.05

Monomer

%

≤1

Melt Index(190℃ 2.16kg)

g/10min

1~30

Glass Transition Temperature

58~60

Melting Point

~160

Tensile Strength at Break

MPa

~50

Tensile Modulus

GPa

3.5~6.0

Impact Strength

J/m

10~13

Mechanical performance comparison

Item

Unit

PP

GPPS

PET

PLA

Density

g/cm3

0.90—0.91

1.04—1.09

1.3—1.4

1.25

Melt index

g/10min

0.2—20

1.5—30

1—30

Tensile strength

MPa

29.6—35

≥58.8

≥60

≥50

Elongation

%

200—700

1.0—2.5

30—70

≥5

Transmittance

%

85—88

88—92

90—92

90—95

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