GRILAMID TR90

Product description
Grilamid TR grades are transparent thermoplastic polyamides based on aliphatic and cycloaliphatic blocks. Grilamid TR 90 offers a variety of interesting properties such as:
1.clear transparency even in high wall thicknesses
2.good light natural colour
3.can be coloured in transparent as well as opaque colours
4.tough
5.stiff
6.good chemical- and stress-crack resistance
7.high flexural fatigue strength

Grilamid TR grades are suitable for production of optical and technical demanding parts in the application fields of:
- Optics
- Electro
- Electronics
- Automotive
- Mechanical engineering
- Domestic appliances

Mechanical Properties		Standard	Unit	State	Grilamid TR 90
Tensile E-Modulus	1 mm/min	ISO 527	MPa	cond.	1600
Tensile strength at yield	50 mm/min	ISO 527	MPa	cond.	60
Elongation at yield	50 mm/min	ISO 527	%	cond.	6
Tensile strength at break	50 mm/min	ISO 527	MPa	cond.	45
Elongation at break	50 mm/min	ISO 527	%	cond.	>50
Impact strength	Charpy,23℃	ISO 179/2-1eU	kJ/m²	cond.	no break
Impact strength	Charpy,-30℃	ISO 179/2-1eU	kJ/m²	cond.	no break
Notched impact strength	Charpy,23℃	ISO 179/2-1eA	kJ/m²	cond.	13
Notched impact strength	Charpy,-30℃	ISO 179/2-1eA	kJ/m²	cond.	12
Ball indentation hardness		ISO 2039-1	MPa	cond.	90
Thermal Properties
Glass transition temperature	DSC	ISO 11357	℃	dry	155
Heat deflection temperature HDT/A	1.80 MPa	ISO 75	℃	dry	115
Heat deflection temperature HDT/B	0.45 MPa	ISO 75	℃	dry	135
Thermal expansion coefficient long.	23-55℃	ISO 11359	10-4/K	dry	0.9
Thermal expansion coefficient trans.	23-55℃	ISO 11359	10-4/K	dry	0.9
Maximum usage temperature	long term	ISO 2578	℃	dry	80-100
Maximum usage temperature	short term	ISO 2578	℃	dry	120
Electrical Properties
Dielectric strength		IEC 60243-1	kV/mm	cond.	34
Comparative tracking index	CTI	IEC 60112	-	cond.	600
Specific volume resistivity		IEC 60093	W·m	cond.	1011
Specific surface resistivity		IEC 60093	W	cond.	1012
General Properties
Density		ISO 1183	g/cm³	dry	1.00
Flammability(UL94)	0.8 mm	ISO 1210	rating	-	HB
Water absorption	23℃/sat.	ISO 62	%	-	3
Moisture absorption	23℃/50% r.h.	ISO 62	%	-	1.5
Linear mould shrinkage	long.	ISO 294	%	dry	0.65
Linear mould shrinkage	trans.	ISO 294	%	dry	0.75
Product-nomenclature acc. ISO 1874:PAMACM12,GT,14-020

This technical data sheet for Grilamid TR 90 provides you with useful information on material preparation, machine requirements, tooling and processing.

MATERIAL PREPARATION
Grilamid TR 90 is delivered dry and ready for processing in sealed, air tight packaging. Predrying is not necessary.

Storage
Amorphous polyamides can be stored over years without negatively influencing it's mechanical properties. However, in order to ensure optimal colour and transparency, Grilamid should not be stored for more then 6 months. At temperatures above 25℃ in combination with long storage temperatures, the oxidation saturation process of the granulate is accelerated. Hence, it is advised to keep storage temperatures below 25℃. The above mentioned effect becomes only visible after injection moulding and shows itself in parts which have a more yellow appearance. Storage facilities must be dry and protect the bags from the influence of weather and damage.

Handling and safety
Detailed information can be obtained from the "Material Safety Data Sheet"(MSDS) which can be requested with every material order.

Drying
Grilamid TR 90 is dried and packed with a moisture content of less than 0.08%. Should the packaging become damaged or the material is left open too long, then the material must be dried. A too high
moisture content can be shown by a foaming melt and silver streaks on the moulded part when injected freely into the atmosphere(free shot).

Drying can be done as follows:
Desiccant dryer
Temperature: max. 80℃
Time: 4-6 hours
Dew point of the dryer: -30℃

Vacuum oven
Temperature: max. 80℃
Time: 4-8 hours

Drying time
If there is only little evidence of foaming of the melt or just slight silver streaks on the part, then the above mentioned minimal drying time will be sufficient. Material, which is stored open over days, which
shows strong foaming, unusually easy flowing, streaks and rough surface on the moulding part, then the maximal drying time is required.
Silver streaks can also be caused by overheating of the material(over 320℃) or by too long melt residence time in the barrel.

Drying temperature
Polyamides are subjected to the affects of oxidation at temperatures above 80℃ in the presence of oxygen. Visible yellowing of the material is an indication of oxidation. Hence temperatures above 80℃ for
desiccant dryers and temperatures above 100℃ for vacuum ovens should be avoided. In order to detect oxidation it is advised to keep a small amount of granulate(light colour only !) as a comparison sample.

At longer residence times(over 1 hour) hopper heating or a hopper dryer(80℃) is useful.

Use of regrind
Grilamid TR 90 is a thermoplastic material. Hence, incomplete mouldings as well as sprues and runners can be reprocessed. The following points should be observed:
1. Moisture absorption
2.Grinding: Dust particles and particle size distribution
3.Contamination through foreign material, dust, oil, etc.
4.Quantity addition to original material
5.Colour variation
6.Reduction of mechanical properties

When adding regrind, special care has to be taken by the moulder.

MACHINE REQUIREMENTS
Grilamid TR 90 can be processed economically and problem-free on all machines suitable for polyamides.
Screw
Wear protected, universal screws with shut-off nozzles are recommended(3 zones).
Screw

Length:	18 D-22 D
Compression ratio:	2-2.5

Shot volume
The metering stroke must be longer than the length of the back flow valve(without decompression distance).
Selecting the injection unit
Shot volume = 0.5-0.9 x
(max. shot volume)

Heating
At least three separately controllable heating zones, able of reaching cylinder temperatures up to 350℃. A separate nozzle heating is necessary. The cylinder flange temperature must be controlla-ble (cooling).

Nozzle
Open nozzles are simple, allow an easy melt flow and are long lasting. There is however the danger that during retraction of the screws following injec-tion of the melt, air maybe drawn into the barrel (decompression). For this reason, needle shut-off nozzles are often used.

Clamping force
As a rule of thumb the clamping force can be esti-mated using the following formula:
Clamping force
7.5kN1) × projected area(cm2)
1)in cavity pressure of 750 bar

TOOLING
The design of the mould tool should follow the general rules for transparent thermoplastics.

For the mould cavities common mould tool steel quality(e.g. hardened steel) which has been hard-ened to level of 56 HRC is recommend.

Gate and runner
To achieve an optimal mould-fill and to avoid sink marks, a central gate at the thickest section of the moulding is recommended. Pin point gate(direct) or tunnel gates are more economical and more com-mon with technical moulding.

To avoid premature solidification of the melt and difficult mould filing, the following points should be considered:
Gate diameter
0.8 × thickest wall section of the injection
moulding part

Runner diameter
1.4 × thickest wall section of the injection
moulding part(but minimum 4mm)

VENTING
In order to prevent burning marks and improve weldline strength, proper venting of the mould cav-ity should be provided(venting channels on the parting surface dimensions: Depth 0.02 mm, width2-5 mm).

PROCESSING
Mould filling, post pressure and dosing
The injection speed should be regulated so as to reduce towards the end of the filling cycle in order to avoid burning. For dosing at low screw revolu-tions and pressure the cooling time should be fully utilised.

Basic machine settings
In order to start up the machines for processing Grilamid TR 90, following basic settings are rec-ommended:

Flange	40℃
Zone1	255℃
Zone2	260℃
Zone3	265℃
Nozzle	260℃
Tool	80℃
Melt	265℃

Pressures/Speeds

Injection speed	medium-high
Hold-on pressure(spec.)	300-600 bar
Dynamic pressure(hydr.)	5-10 bar
Screw speed	50-100 min-1

CUSTOMER SERVICES
EMS-GRIVORY is a specialist for polyamide syn-thesis and polyamide-processing. Our customer services are not only concerned with the manufac-turing and supply of engineering thermoplastics but also provide a full of technical support program:
1.Rheological design calculation/FEA
2.Prototype tooling
3.Material selection
4.Processing support
5.Mould and component design

We are happy to advice you. Simply call one of our sales offices.

关健词：PA12 TR90