PLA Polymer S2-02

• Material: Polyethylene/PE
• Usage: General Plastics
• Plastic Properties After Heated: Thermoplastic Plastics
• Plastic Forming Method: Film Pressure
• Color: White
• Density (g/cm3): 1.25±0.05
• Model NO.: S2-02
• Melt Index, G/10min (190ºC/2.16kg): 2-10
• Melting Point (ºC): 155-160
• Glass Transition Temperature (ºC): 58-61
• Molding Shrinkage Rate: 0.003
• Tensile Strength (MPa): ≥50
• Elongation at Break (%): ≥3.0
• Transport Package: Well Packaged Products Can Be Used Directly
• Specification: S2-02
• Trademark: SWE
• Origin: China
• Production Capacity: 20mt/Year

Product Description

Introduction

Biomaterials PLA polymer S2-02 is a thermoplastic resin derived from annually renewable resources and is specifically designed for sheet extrusion applications.

Products Properties of S2-02

	S2-02
Physical Properties
Density (g/cm^3)	1.25±0.05
Melt Index, g/10min (190ºC/2.16kg)	2-10
Melting Point (ºC)	155-160
Glass Transition Temperature (ºC)	58-61
Mechanical Properties
Tensile Strength (Mpa)	≥50
Elongation at Break (%)	≥3.0
Impact Strength (KJ/m^2, Izod)	3-5

Applications

    Many products can be produced from S2-02, and the application field of this  resin is extended gradually. Suitable products including: cold drink cup, fruit container,  salad plate, fruit plate, egg tray, electronics tray, IC card, cup lid or cake lid and etc.

Processing Information

PLA resin S2-02 can be processed in traditional PET extruder. A sheet thickness between 0.2-1.0 mm is recommended. General equipment requirements are: screw with L/D ratio between 24:1 to 32:1 and smooth stuff barrel. Stuff is stable in melt form given it is properly dried.

PLA resin S2-02 is different from other resins, and special purging sequences should be followed:

1. Clean extruder and bring temperatures to steady state with low-viscosity, general-purpose polystyrene or polypropylene.

2. Contamination of hopper system should be avoid, and the humidity of the a should be kept below -40ºC air dew point.  

3. PLA resin can be introduced into extruder after step 1 and 2.  

4. Adjust the temperature of equipment to the operating condition.

5. When shutting down, the machine should be cleaned with low-viscosity polystyrene or polypropylene.  

Note:  

1. It is critical that all drying and conveying/receiving systems should be free of all other contaminant and is vacuumed to ensure that there is no remaining other polymer dust before adding PLA. Since the presence of other polymer contaminant that cannot melt at PLA operating temperature will block screens.

2. When cleaning extruder with polypropylene, the thermally cross-linked one should be avoid.  

 

Drying

S2-02 has been processed by drying crystallization at our factory. Highest heat stability of the resin is 110ºC and the moisture content is less than 200 ppm. The resin is stored in Aluminum foil bag, protected by box or bag as the outer packaging, and can be used directly. It is more favorable if resin user can re-dry the resin with proper drying equipment and lower the moisture content  to 100 ppm or less. It will enhance the processability of the resin and the quality of the sheet.

When re-drying the resin, un-dehumidified hot air is forbidden (by using un-dehumidified air, it will speed up water absorption of PLA resin and cause degradation on the resin). Only dehumidified air can guarantee good drying effect of PLA resin in desiccator.

Recommended drying conditions of S2-02

Drying Parameter	Typical Settings
Residence Time (hours)	2-3
Air Temperature (ºC)	90
Air Dew Point (ºC)	-40 ~ -42
Air Flow Rate (m^3/hr-kg resin)	>1.85

Sheet Extrusion

   A general-purpose single-screw extruder with L/D ratio from 24:1 to 32:1, and a feed-throat cooling system can be used to extrude PLA sheet. It is recommended that static mixers or melt pump should be installed prior to the die to ensure the stability of material conveying. At the same time, screen is also recommended to obtain high qualitysheet and large output. Typical PLA sheet extrusion parameters are listed as follows:

Process condition

Extrusion Area	Temperature Setting (ºC)
Feed Throat	20-40
Zone 1	180-200
Zone 2	180-200
Zone 3	180-200
Filter	180-200
Melt Pump	180-190
Die	180-190

Note:

1. Temperature settings can be optimized during the production process.

2. If screw blockage phenomenon happens in zone 1, the correspondence temperature should be raised.

Most conventional sheet dies can been used to extrude PLA sheet successfully. Hanger-type die is welcome, and the die gap should be set at approximately 50% greater  in thickness than the desired sheet dimension. The use of width control system is not  recommended since there is possibility of resin degradation in the dead angle produced  by the width control system, resulting in bad properties of PLA sheet.  

Sheet forming should be done on 3-roll stack, inclined or horizontal roll stacks are  both acceptable. At the same time, 3-roll stack should be equipped with an accurate  temperature control system.  

3-roll stack temperature profiles vary depending on the output, melt temperature and roll diameters. The rolls can be divided into three parts according to the distance from the  die.

Recommended original temperature settings are listed as follows:  

Top roll	45ºC
Middle roll	35ºC
Bottom roll	25ºC

Note:

1. Above mentioned temperatures can be adjusted according to the production capacity, melt temperature and roll diameter during the process.

2. Lactic acid monomers may occur on the top and middle roll if the rolls temperature is too low. Whereas too high temperature may make PLA sheet stick to the rolls.

The stiffness of PLA is similar to PS, but quite different from either PP or PET.

Be careful of sharp edges on thin cast sheet. Gloves must be worn to minimize the risk of cuts. PLA also has high elastic modulus, and tension control system must be equipped in the rolling device.  

Recovery treatment of renewable materials

   PLA scraps can be reused (such renewable materials should not be stored longer than 3 months, and it should not be added to the mix at loadings above 35% ). Owing to the demand that the moisture content of sheet extrusion should be lower than 200 ppm, the renewable materials must be treated 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. Add the mixture into crystallization autoclave, begin to stir the mixture at a speed of 3 rpm and start to raise the temperature: set the temperature at 60ºC for 20min, 80ºC for 10 min, 95ºC for 10min, at last at 110ºC for 30 min, and then lower the temperature gradually. The whole crystallization process lasts for about 1.5 hours.

Crystallization method 2:

   By using Kreyenborg infrared crystallization equipment, the materials are heated byinfrared and stired by rotation mixer after being added into the infrared crystallization rolling barrel. The merit of this method is that the crystallization and drying process can be carried out simultaneously and the process can be finished within 15~20 min.

Crystallization method 3:

   After being pre-dried at low-temperature, the renewable materials is then extruded and palletized, after that, the crystallization process can be carried on in PET crystallization equipment.

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


Frequently Asked Questions

Q1: May I get one sample before placing order?
Re: Yes, Sample are available. For normal products, samples are for free and you just need to bear the freight; 

For those high value products, you just need to freight and certain product cost. When we both cooperate for 

some times or when you are our VIP customer, free sample will be offered when you need.

Q2: Which payment is available for your company?
Re: T/T, L/C or Alibaba trade insurance. You can choose the one which is convenient for you. 

Q3: How and when can I get my goods after payment?
Re: For small quantity products, they will be delivered to you by international courier(DHL, FedEx, TNT etc.) 

or by air. Usually it will cost 3-5days that you can get the goods after delivery.For large quantity products,

shipping by see is worthwhile.It will cost days to weeks to come to your destination port, which depends on 

where the port is.

Q4: Is there any possible to use my appointed label or package?
Re: Yes. If needed, we'd like to use label or package according to your requirement. 

Q5: How can you guarantee the goods you offer is qualified? 
Re: We always believe honesty and responsibility are basis of one company, so whatever products we provide 

for you all are qualified. We will have goods tested and provide COA before delivery for sure.