Thermoplastic Polyurethane Elastomers (TPU) Elastollan®– Processing Recommendations

Technical Information Contents

General Storage 4 Recommendations Drying 5 Colouring 6

Additives 6

Use of Regrind 6

Post-treatment 7

Health & Safety at Work 8

Disposal 8

Processing Machine Design 9 Injection Moulding Processing Parameters 10 Mould Design 12

Shrinkage 14

Inserts 14

Special Processing Methods 15

Trouble Shooting Guidelines 15

Processing Machine Design 16 Extrusion Processing Parameters 17 Die Design 18

Cooling and Calibration 19

Extrusion Techniques 20

Special Processing Methods 22

Trouble Shooting Guidelines 22

Finishing Procedures Welding 23 Bonding 23

Surface Finishing 23

2 Contents

Machining Machining Parameters 24 Drilling 24 Turning 25

Milling 25

Cutting 25

Grinding 25

Punching 25

Quality 26 Management

Index of Key Terms 27

Edition: November 2011 3 General Recommendations

Storage

Elastollan is the protected trade mark Moisture absorption of our thermoplastic polyurethane Polyester-TPU elastomers (TPU). These materials Hardness 80 Shore A – 64 Shore D are used for injection moulding, 0,80

extrusion and blow moulding. 0,70

] 1

% 0,60 The following recommendations [ should be observed in the process- 0,50

ing of Elastollan materials. 0,40 Humidity

Elastollan grades are supplied uncol- 0,30 oured, in diced, cylindrical or lentil- 0,20 2

shaped form. The materials are 0,10 hygroscopic i.e. dry Elastollan, when 0,00 exposed to the atmosphere will 0 12345678 rapidly absorb moisture. Polyether- Time [h] based Elastollan grades absorb 1 – Standard atmosphere 40°C/92% rel. hum. more rapidly moisture than polyester- 2 – Standard atmosphere based grades. 23°C/50% rel. hum. Fig.1 Figures 1 and 2 show the rate of moisture absorption.

Storage in dry conditions, if possible Moisture absorption at room temperature, is therefore Polyether-TPU recommended. Hardness 80 Shore A – 64 Shore D

0,80 In order to prevent condensation, ] 0,70 %

material stored in cool conditions [ 1 should be brought to room tempera- 0,60

ture before opening the container. 0,50 Humidity Containers should be tightly closed 0,40

0,30 after use. The granulate should be 2

exposed to the surrounding air only 0,20 for as long as absolutely essential. It is therefore important to cover the 0,10 feed hopper of the processing 0,00 0 12345678 machine. Drying is recommended if Time [h] the container has been opened 1 – Standard atmosphere several times. 40°C/92% rel. hum. 2 – Standard atmosphere 23°C/50% rel. hum. Fig. 2

4 General Recommendations

Drying

Excessive moisture content in the Conventional circulating-air ovens, granulate can lead to processing vacuum drying cabinets and problems and to a reduction in the dehumidified air dryers are suitable quality of the finished part. for this purpose. For recommended drying parameters see table 1. Foaming of the plasticized material or the formation of gas bubbles in the When using circulating-air ovens, the melt are indications that the moisture layer of granulate should not exceed content is excessively high. Vari- 4 cm in height. With dehumidified air ations in output during extrusion dryers, the total available capacity processing are in many cases may be utilized. After drying, the attributable to insufficient pre- granulate should be immediately drying. stored in dry containers which can be securely sealed. In order to ensure optimal perform- ance properties in the finished When colour masterbatches and Elastollan parts, it is necessary that additives are used, care must be the material is dried before process- taken to see that they are also ing. Water content of the granulate dried. Therefore it is better to should not exceed 0.02%. pre-mix with the granulate before the drying process to make sure that the whole product is dried.

Drying recommendations Elastollan hardness Drying time Drying temperature Circulating air Dehumidified air Shore A 78 to 90 2 to 3 hours 100 to 110˚C 80 to 90˚C

harder than Shore A 90 2 to 3 hours 100 to 120˚C 90 to 120˚C Ta ble 1

Drying diagram for Elastollan

0,40

0,35 ]

% 0,30 [ Dehumidified air 0,25 dryer 110 °C Circulating-air 0,20 oven 110 °C

0,15 Circulating-air oven, 90°C

Residual moisture 0,10

0,05

0,00 0306090120 150180 Drying time [min] Fig. 3

5 General Recommendations

Colouring

All grades in our Elastollan range can There is a risk that non-Elastollan- be coloured. Masterbatches based based colour masterbatches will on TPU are most suitable for this prove incompatible with Elastollan purpose. The normal level of addition grades. Poor pigment dispersion and of colour masterbatch is 2%, how- a lack of colouring strength, as well ever, Elastollan grades containing as poor surface finish and possible pre-included additives, e.g. flame loss of quality may result. retardant types, may require a high loading to achieve the full depth of colour.

Additives

Various additives can be used to • Anti blocking agents enhance the properties of Elastollan materials. Following additives • Release agents supplied as Elastollan master- batches are available: • UV stabilizers

Use of Regrind

Depending on finished parts quality Material which has been contam- requirements, up to 30% of regrind inated or degraded is not suitable for can be recycled with virgin material. reprocessing. The material type and Shore hard- ness of the regrind should be iden- Continuous recycling of regrind can tical to that of virgin Elastollan and lead to a reduction in the quality of has be free of contaminations. finished parts. Certain quality requirements laid down in specifica- Ideally, regrind should be diced, tions may exclude the use of regrind dried and re-used without inter- material. mediate storage.

6 General Recommendations

Post-treatment

Moulded Elastollan parts require During annealing articles with low several weeks storage at room tem- dimensional stability should be perature to attain full mechanical stored in such a way that deforma- properties. To achieve optimal func- tion is avoided. tional properties in a shorter period, annealing of the finished parts is Extruded parts are annealed only in necessary. This heat treatment can special cases. be undertaken in a circulating-air oven. Annealing: Recommended duration and Table 2 shows typical values for temperature: 20 hours at 100 "C cured vs uncured Elastollan grades.

Effect of curing on Elastollan properties Properties Unit DIN Cured Uncured Uncured Uncured 20 h20 h7 d35 d 100°C23°C23°C23°C Elastollan C 90 A 55 Hardness Shore A53505 91 91 92 92 Tensile strength MPa53504 48 42 44 46 Elongation % 53504 580 570 550 500 Tear strength N/mm 5351598808385

Abrasion mm3 53516 22 54 30 29 Compression set at 70 ° %53517 33 60 53 50 Elastollan C 1190 A 55 Hardness Shore A53505 90 89 91 91 Tensile strength MPa53504 48 43 45 46 Elongation % 53504 550 560 530 500 Tear strength N/mm 5351585747379 Abrasion mm3 53516 19 48 34 27 Compression set at 70 ° %53517 36 70 65 65 Table 2

7 General Recommendations

Health & Safety at Work

Depending on the grade used, Basically, onset of decomposition Elastollan can be processed and can be expected from temperatures machined over a wide range of tem- of around 230°C upwards. Where perature. elastomer melts emerge to the air, there is a possibility that the vapours As with all natural or synthetic released under such conditions will organic substances, decomposition affect the workplace. is possible above certain tempera- tures. The rate of decomposition will For this reason, an effective extrac- depend on the temperature applied tion system, especially in the melt and the grade of material used. outlet zone, is recommended.

Disposal

Elastollan materials are fully reacted and present no hazard to the environ- ment. Waste can therefore be dis- posed at public waste disposal sites or refuse incineration plants. The official regulations on waste disposal should be observed.

For further information see our safety data sheets.

8 Processing Injection Moulding

Machine Design

Screw injection moulding machines A check ring (shut-off ring) should be with single-flighted, 3-zone screws incorporated. Both free flow and are suitable for the processing of automatic shut off nozzles are Elastollan. Because of the high shear suitable, although care should be stress, short compression-zone taken to ensure smooth flow through screws are not suitable. the nozzle channels. Dead spots where the melt could accumulate The following screw design has and become charred should be proven successful (see Fig. 4): avoided.

The compression ratio should be around 1:2 and should not exceed 1:3. The recommended flight depths are shown in Fig. 5.

Screw configuration (diagrammatic view)

D

Metering zone Compression zone Feeding zone 0,25 L 0,35 L 0,40 L

L = 18–22 D Fig. 4

Relation: screw diameter – flight depth (feeding zone)

14 ] m

m 12 [

10

8

6 Flight depth (feeding zone)

4 30 40 50 60 70 80 90 100110 120 Screw diameter [mm] Fig. 5

9 Processing Injection Moulding

Processing Parameters

To ensure trouble-free processing temperature controllers accordingly and consistently high quality (see table 4). moulded parts, precise and constant temperature control in the injection As Elastollan melts are shear- moulding cylinder is necessary. sensitive, excessive screw speed can cause reduced product The temperature should increase by properties. roughly 10 to 20°C from the feeding zone to the metering zone. Nozzle Fig. 6 shows recommended screw temperature should be adjusted to speeds in relation to screw diameter. suit the melt temperature. Where cycles are interrupted for Table 3 shows the recommended longer periods, the material remain- barrel temperatures for various ing in the cylinder will become over- ranges of hardness: heated. It is therefore necessary to purge out the cylinder before It is recommended to measure melt resuming production. temperature and to adjust machine

Recommended barrel temperatures in °C Shore hardness Heating zone temperature Nozzle temperature

60 A–80 A 170–210 200–210 85 A–95 A 190–220 210–225 98 A–74 D 210–230 220–240 Table 3

Recommended melt temperatures in °C Elastollan hardness 60 Shore A to 80 Shore A 190 to 205 Elastollan hardness 85 Shore A to 95 Shore A 205 to 220 Elastollan hardness 98 Shore A to74 Shore D 215 to 235 Table 4

Relation: max. screw speed – screw diameter

100 ]

m 80 p r [

60 max. circumferential 0,2 m/s Screw spee d 40

20 30 40 50 60 70 80 90 100110 120 Screw diameter [mm] Fig. 6

10 Processing Injection Moulding

Processing Parameters

Cavity pressure pattern during processing

ps Injection pressure 100–1000 bar pn Holding pressure 100–1000 bar ps pst Back pressure 5– 20 bar p n (System pressure) p

Injection speed: as low as possible, dependent on gating, wall thickness and flow Pressure

pst

Ti me t Fig. 7

The following machine parameters Injection Speed are especially important for the The correct injection speed is processing of Elastoflan (see Fig. 7): dependent on gating, wall section and flow. It should be kept as low as Injection Pressure and Holding possible. Pressure These factors influence dimensional A typical cycle sequence for stability and ease of demoulding of Elastollan is illustrated in dia- the finished parts. If holding pressure grammatic form in Fig. 7. is too low, sink marks may occur. If injection pressure is too high, then Cycle Time demoulding is more difficult. The cycle time depends on crystalli- sation-behaviour and demoulding Back Pressure characteristics. Demoulding time is This effects the homogenization of determined primarily by mould the melt. It should not be set too high, temperature, wall section and hard- owing to the shear sensitivity of the ness of the material. material. Fig. 8 shows cycle time in relation to wall thickness for grades of different Shore hardness.

Cycle time in relation to wall thickness 200

180

160 60 Shore A 140 ]

s 120 [ 85 Shore A

100

Time 64 Shore D 80

60

40

20

0 123456789 Fig. 8 Wall thickness [mm]

11 Processing Injection Moulding

Mould Design

Materials for Mould Construction Runner systems Materials commonly used for tools, like steel or steel alloys, are suitable for Elastollan mouldings. Moulds made from non-ferrous metals, mainly aluminium, are also working successfully; these cost-effective moulds are often used in footwear manufacture.

Sprues The maximum sprue diameter should Fig. 9 not exceed the maximum wall thick- ness of the moulding. The diameter of the sprue cone should be adjusted to the nozzle and exceed the nozzle diameter by 0.5 mm. The gate should be located in the area of maximum wall thickness.

Sprue cones should be as short as possible and with a minimum angle of 6°. A sprue puller is advisable for easier demoulding.

Runners The melt properties of Elastollan Fig. 10 require large diameter runners to avoid localized shearing and to Gating enable the maximum pressure Gates for the processing of transfer to ensure mould filling. Elastollan should be large, to ensure adequate holding pressure and to For Elastollan, the best flow charac- avoid sink marks. Critical shear rate teristics are achieved by using a is 25 000 s-1. circular runner cross section.

If hot runners are used preferably external heated systems should be selected. Internal heated systems are not suitable.

Multi-cavity tools need a balanced runner system.

Runner cross section

rectangu- half-moon trapezoid round- round lar trapezoid

unfavourable better best

Fig. 11

12 Processing Injection Moulding

Mould Design

Designs commonly used include Recommended types of gate sprue, diaphragm, ring and film for Elastollan gates. Small parts may also be injected through pin gates.

Submarine gates are not recom- mended because of the high elastic- ity and possible shear degradation of the material. The softer Elastollan grades are especially prone to prob- lems with this type of gate. Ring gate

Venting Fig. 12 Air must be able to escape easily from the mould cavities during injec- tion of the melt, to prevent com- pressed air causing burn marks. Vent channels of 0.02 to 0.05 mm in depth are best located at the parting line, at inserts and at pins.

Mould Surface To facilitate demoulding, particularly when processing the softer Film gate Elastollan grades, mould surfaces Fig. 13 with a roughness height of approx. 25 to 35 µm are recommended.

Polished and chrome-plated mould surfaces are less suitable, since, especially with the softer grades, they promote sticking of the parts to the mould surface.

Demoulding Sprue gate The flexibility of Elastollan in the lower Shore hardness range allows Fig. 14 quite large undercuts. Experience shows that short-term overstretch- ing of less than 5% will not lead to Mould temperatures may vary from permanent deformation. 15 to 70°C, depending on the Elastollan grade and type of For trouble-free demoulding, ejec- moulding. tors should be two to three times larger than for harder thermo- Possible distortion of the moulded plastics. They should be provided parts can be avoided by varying the with venting channels, to prevent temperature in each half of the vacuum during demoulding. mould.

Mould Temperature Control A good mould temperature control system is essential for production of high-quality mouldings. Mould tem- perature has an influence on surface quality, shrinkage and distortion.

13 Processing Injection Moulding

Shrinkage

The shrinkage of Elastollan mould- For this reason it is difficult to predict ings is influenced by the following shrinkage with any great accuracy. parameters: Fig. 15 shows total shrinkage for • part design unreinforced Elastollan grades in • wall thickness relation to wall thickness and Shore • gate design hardness. • processing conditions, in particu- lar melt temperature, injection Depending on glass fibre content pressure, holding pressure, glass fibre reinforced Elastollan mould temperature. grades show shrinkage of 0.05 to 0.20% in flow direction and of 0.1 to Total shrinkage is a result of moulding 0.5% transversal to flow direction. shrinkage and post-shrinkage which occurs not only during annealing, but also during longer-time storage of the parts.

Shrinkage in relation to wall thickness

2,5 Hardness 70 Shore A

Hardness 95 Shore A 2,0

Hardness 74 Shore D

1,5 ] % [

1,0 Shrinkage

0,5

0 01234567891011121314 Wall thickness [mm] Fig. 15

Inserts

Inserts can be moulded-in without Bonding may be further improved by difficulty. However, for this purpose, the use of primers. Elastollan grades without lubricant are preferred. It is helpful to temper the inserts.

Metal inserts must be free from grease, and should have features for mechanical anchorage, such as holes, undercuts, knurled grooves or notches.

14 Processing Injection Moulding

Special Processing Methods

Following methods are suitable to layer. Besides the combination of combine other thermoplastic different thermoplastics it is possible materials with Elastollan: to use regrind as core component and virgin grades as outer skin. Multicomponent Injection Moulding Gas Injection Moulding Injection moulding of Elastollan and It is in principle similar to sandwich compatible plastic materials on moulding. Gas is injected as core multicomponent machines creates component for weight reduction. good bonding without using addi- tives and mechanical anchorage. Polyolefin based materials are incompatible with Elastollan.

Sandwich Injection Moulding This is a special method of multicom- ponent injection moulding where a core component is combined with a different plastic material as outer

Trouble Shooting Guidelines

Trouble shooting guidelines Melt Mould In- Holding Back Shot Clamp- Cooling Venting Mois- Material Gate Lubri- Resi- temper- temper- jection pres- pres- size/ ing time ture con- size cant dence ature ature speed sure/ sure Melt pres- content tami- time time cushion sure nation Contamination Bubbles/Blisters Burned spots Distortion/Shrinkage Flow lines Gloss/Matt surface Flashing Short shot Sink marks Splay marks Demoulding Material degradation Increase to solve problem Reduce to solve problem Increase or reduce to solve problems Table 5

15 Processing Extrusion

Machine Design

Diagrammatic view of a three-section screw

D

Metering zone Compression zone Feeding zone 0,3 L 0,4 L 0,3 L L = 25–30 D

Fig. 16

Single-screw extruders with a com- Barrels with a grooved feeding zone pression ratio of 1:2 to 1:3, preferably have proven successful in practice, 1:2.5, are recommended for and provide the following benefits: processing of Elastollan. •constant feeding characteristics Our experience shows that three •improved pressure build-up section screws with a L/D ratio of •increased output 25 to 30 are most suitable. If grooved feeding zones are used, Three-section screws should have a cooling is necessary. It is also continuous, constant pitch of 1D. advisable to use a screw with a mixing section, in order to improve The radial clearance between screw homogeneity of the melt. Such and barrel should be 0.1 to 0.2 mm. mixing sections should, however, be designed to avoid shear For processing of Elastollan multi- degradation. zone screws, e.g. barrier screws (undercuts >1.2_ mm) have also proven suitable. Short screws with a high compression ratio are unsuitable.

Relation: screw diameter – flight depth (feeding zone)

14 ]

m 12 m [

10

8

6 Flight depth (feeding zone )

4 30 40 50 60 70 80 90 100110 120 Screw diameter [mm] Fig. 17

16 Processing Extrusion

Machine Design

Use of breaker plates and screen Extrusion of thermoplastic poly- packs is recommended. Good urethane requires a more powerful results have been obtained from a motor than for other thermoplastics. combination of two screens of 400 Power consumption is between 0.3 mesh/cm2 as backing plates and two and 1 kWh per kg output, depending fine screens of 900 mesh/cm2. Finer on screw design. screens may be necessary for certain applications (e.g. film production). Melt pumps have proved successful for continuous melt flow. Depending on screw diameter and type of die, breaker plates should have holes of 1.5 to 5 mm in diameter.

Processing Parameters

Processing Temperature Screw Speed The following temperature ranges, Since thermoplastic polyurethanes which are dependent on the hard- are shear-sensitive, excessively high ness of the Elastollan grades are screw speeds may lead to a reduc- recommended: tion in product properties.

Fig. 18 shows the relation of max. screw speed to screw diameter.

Recommended temperatures for processing in °C Shore Heating zones hardness Cylinder Adapter Die head Nozzle 60 to70 A 140–175 160–175 165–170 160–165 75 to 85 A 160–200 175–200 175–205 170–205 90 to 98 A 170–210 200–220 195–215 190–210 Table 6

Relation: max. screw speed – screw diameter

100 ]

m 80 p r [

max. circumferential speed 0,15 m/s 60 Screw speed 40

20 30 40 50 60 70 80 90 100 110120 Screw diameter [mm] Fig. 18

17 Processing Extrusion

Processing Parameters

Melt Pressure Cleaning of the Extruder Melt pressure is dependent on the When changing grade or after several head-design and the die gap, and on days of continuous operation, clean- melt temperature. Normally the ing of the extruder is recommended. maximum pressure at the adapter is 300 bar, however, peaks of up to Polypropylene or HDPE, which 1.000 bar can occur at start-up. require higher processing tempera- Thus, for safety at start-up, a variable tures, are suitable for this purpose. screw drive is recommended. If In addition, it is sometimes neces- needed, starve feeding is possible. sary to use a purging compound.

Die Design

To ensure a constant melt flow, it is In all other respects, guidelines for important to operate with narrow head design are the same as for the cross-sections and to avoid dead extrusion of other thermoplastics. spots in the die. This will cause automatic self-cleaning of the die. Fig. 19 shows examples of typical dies:

Wire and cable sheathing dies

Pressure die Tube die

Fig. 19

18 Processing Extrusion

Die Design

For extrusion of tubes and profiles, constant discharge. Land length dies with a relatively long land are should be two to four times nozzle recommended. This reduces the diameter. shear stresses, thus permitting a

Tube extrusion die Entry bush Body Spider To rpedo Pin Die support Die

Fig. 20 Breaker plate

Cooling and Calibration

Freshly extruded thermoplastic Calibration devices as shown in polyurethanes have a relatively low diagrammatic view in Fig. 21 are melt strength and are therefore prone suitable to support the extrudate. to distortion. This necessitates effec- tive cooling. The water bath should It is essential to provide a lubricating be close up to the extruder head. film of water between the surface of Chilled water is preferred. Instead of the extrudate and the calibrating die. cooling baths a cooling line with This can be achieved by a water spray nozzles is also suitable. spray ring located before the entry into the cooling bath. The length of cooling bath required for Elastollan grades generally Fig. 22 describes the layout of a tube exceeds the requirement for other extrusion line for Elastollan. thermoplastics. The length depends on the grade of material, extrudate shape and section, and haul-off speed.

Due to high coefficient of friction, compared to general thermoplastics, active calibration of thermoplastic polyurethane is not possible.

Calibration die

Fig. 21 19 Processing Extrusion

Cooling and Calibration

Cooling bath for tube extrusion

Cooling water tank Vacuum tank Calibration

Water pump Heat exchanger Vacuum pump

Fig. 22

Extrusion techniques

Tubes and Profiles Sheathing Tubes and profiles are mostly Sheathing of cables, hoses, etc. is extruded horizontally. However, thin- carried out by using a crosshead (see walled tubes, e.g. fire-hose linings, Fig. 23), equipped with a pressure or are generally extruded vertically. tube die (see Fig. 19). The inner-core which is to be sheathed must be dry It is necessary to supply supporting and free from grease, in order to air to prevent collapsing of the tubes. avoid blistering after extrusion and to ensure good bonding. To assist shape stability for hollow shapes it is recommended to use vacuum.

The guide rollers in the cooling bath should be matched to the shape of the extrudate.

Diagrammatic view of a crosshead

Body Torpedo Die

Wire guide

Breaker plate Entry bush Die support Pin Fig. 23

20 Processing Extrusion

Extrusion Techniques

Film Blow moulding Special Elastollan grades are suit- Blow moulded articles can be man- able for the manufacture of blown ufactured from selected Elastollan film. grades using conventional blow moulding machines. Fig. 24 shows, in diagrammatic form, a film blowing head. To improve ease of demoulding, the use of a mould with roughened Diagrammatic view surface (approx. 35 µm) is recom- of a film blowing head mended. Wall thickness control is necessary to compensate for elonga- Mandrel tion of the parison. Fig. 26 shows a Die torpedo head for blow moulding.

Diagrammatic view of a torpedo head

Spiral mandrel

Drive Barrel Extruder Torpedo Barrel

Mandrel Deflector piece Die Fig. 24 Parison

Films of greater wall thickness can be Fig. 26 produced by the flat film extrusion process using a sheet die (see Fig. 25); normal extrusion grades are suitable.

Diagrammatic view of a sheet die

Fig. 25

21 Processing Extrusion

Special Processing Methods

Following special methods are suita- Thermoplastic Foam Extrusion ble for Elastollan: for weight reduction and to achieve special properties. Coextrusion to achieve a combination of proper- Two methods are applicable: ties of different thermoplastics in one processing step. • Chemical expanding of the melt by addition of expand- For bonding reasons materials have ing agent with conventional to be compatible. Compatibility can extruders; foam density between 0.4 and 1.0 g/cm³ is attainable. differ between Elastollan ether and ester types. • Physical expanding of melt by injection of gas into the extruder. Foam density below 0.4 g/cm³ is attainable. The structure of foam is controlled by a nucleating agent.

Trouble Shooting Guidelines

Trouble shooting guidelines Melt/ Die Die Screw Land Homo- Moisture Material Cooling Lubricant Cylinder tempera- pressure speed/ length genisation content contami- feeding tempera- ture Output nation zone ture Pulsation Rough surface Surface streaks Bubbles/Blisters Flow lines/ Spider lines Excssive blocking Unmelted particles Dimensional variations Unsufficient dimensional stability Melt fracture Material degradation

Increase to solve problem Reduce to solve problem Increase or reduce to solve problems Table 7

22 Machining

Welding

The following welding techniques Decisive for the weld strength are: have proved successful for the the temperature which enables bonding of finished and semi-finished below decomposition temperature a Elastollan parts: sufficient flow of Elastollan, and the pressure which generates the melt Injection moulded parts are mainly flow and sealing of the two layers. bonded by hot plate, ultrasonic The pressure also provides stabilisa- (harder types), high frequency- or tion of the welding joint during setting friction welding. time.

For semi-finished parts and profiles In all welding operations, provision hot plate- or friction welding is must be made for the extraction of used as well as hot gas welding. gases (see page 8, Health & Safety at Work). For films best results are achieved by thermal sealing, heat impulse welding or high frequency welding.

Bonding

In order to facilitate bonding it is Adhesives manufacturers offer suita- recommended to use Elastollan ble systems for this purpose. grades without lubricant. Polyurethane based elastic adhe- The usual preparatory work should sives have proved successful in the be undertaken before bonding. bonding of Elastollan parts. Epoxy resin adhesive are used for bonding to metals and other hard materials.

Surface Finishing

Printing and painting are possible Suitable printing and painting when lubricant-free Elastollan systems are offered by paint and dye grades are used. manufacturers.

23 Machining

Machining Parameters

Owing to the exceptional toughness In machining Elastollan, excessiv and tear strength of Elastollan, generation of heat should be machining is not without problems, avoided. Accordingly, always pro- and much depends on the hardness vide for cooling by compressed air of the material to be machined. With or emulsion. all tools used for machining Elastollan, care should be taken to The following table gives recom- ensure that cutting edges are mended values for machining correctly sharpened. Elastollan:

Parameters for machining Elastollan Turning Milling Drilling Grinding

Clearance angle Rake angle Setting angle x

Point angle

. . . . of

Depth of cut a [mm] à 15 2–8/ 0.1–3

Drilling: Hollow drill, twist drill, tooth face-milling cutter Grinding: Grinding wheel with open structure and low hardness; high porous type (grain size 60 -80): Table 8

Drilling

Drilled holes generally turn out to be smaller than the nominal diameter of the drill. For qualities up to 80 Shore A, the reduction in diameter is around 4–5%. As a rule, hollow drills pro- duce holes with greater dimensional accuracy.

During drilling efficient cooling is recommended and the drill should be lifted frequently.

24 Machining

Turning

In order to reduce cutting forces and heat, tools used for turning should have smaller-diameter cutters than those used for metal.

Milling

Conventional milling machines and manual milling cutters may be used for Elastollan. Where cutter heads are used, in order to ensure good chip formation, the number of blades should be kept to a minimum.

Cutting

Cutting blades with close pitch and large setting are suitable.

Grinding

Elastollan parts may be ground.

Grinding wheels should not be too wide to prevent overheating at the grinding point (max. 20 mm). Cooling is advantageous and will permit a higher grinding speed.

Punching

The shape of the stamped surface will depend on material hardness. Fig. 27 shows the results of stamping of soft und hard Elastollan types.

Results of stamping Soft Hard

Fig. 27

25 Quality Management

Lagerung

Quality Guidelines Management-Sytems / Certificates • The orientation on customers Customer satisfaction is the basis for processes and on employees are sustained business success. important elements of the Quality Therefore, we want to meet the Management. customers‘ requirements for our • The customer requirements are products and services, now and for determined regularly and fulfilled long-term future. To ensure success in with the aim of the increase of the a reliable way, BASF Polyurethanes customer satisfaction. Europe introduced a quality manage- • Targets are agreed with the persons ment system several years ago responsible for process in all units including all divisions. Each business of competence and the realization process is regularly assessed and is followed regularly. further developed based on informative • Targets, methods and results of the performance indicators. The target is Quality Management are continually to reach optimum efficiency and almost imparted in order to support the perfect coordination of all activities and consciousness and the cooperation operations. Each employee is asked to of all employees in the process of make a contribution to quality assu- the continuous quality improvement. rance and continuous improvement • Instead of later debugging, the with its capabilities and ideas at its principle of avoidance of defects workplace. is realized. • Organizational and personnel measures will be concentrated on Our integrated Quality and Environ- effective quality management to mental Management-System is based ensure the implementation of the on following standards: quality targets. DIN EN ISO 9001

ISO/TS 16949 (with product develop- ment)

DIN EN ISO 14 001 (environmental management system)

26 A G R

B S H

C I

D M

T

E

P U

V

F W Q

27 BASF Polyurethanes GmbH

With top quality products, a reputation for good customer service and continu- ous progress and development, Elastollan has secured a firm position in numerous markets.

We want to share our know-how and experience to contribute to your own success: The versatile Elastollan is the ideal material to fulfill your require- ments.

For further information, the following detailed brochures are available upon request: b Thermoplastic Polyurethane Elastomers: Elastollan b Elastollan – Product Range b Elastollan – Material Properties b Elastollan – Electrical Properties b Elastollan – Chemical Resistance

®= Registered Trademark of BASF Polyurethanes GmbH BASF Polyurethanes GmbH The data contained in this publication are based on our current knowledge and experience. In view of the many European Business Management factors that may affect processing and application of Thermoplastic Polyurethanes our product, these data do not relieve processors from Elastogranstraße 60 carrying out their own investigations and tests; neither do these data imply any guarantee of certain properties, 49448 Lemförde nor the suitability of the product for a specific purpose. Germany Any descriptions, drawings, photographs, data, proportions, weights etc. given herein may change with- Telephone ++49 (5443) 12-2500 out prior information and do not constitute the agreed Telefax ++49 (5443) 12-2555 contractual quality of the product. It is the responsibility of the recipient of our products to ensure that any E-Mail [email protected] proprietary rights and existing laws and legislation are www.pu.basf.eu observed. (10/10) KU/WM, MP 208-10/10 GB