PTS Plastic Technologie Service Marketing- & Vertriebs-GmbH

16.02.2010
Material challenge for the "Dragon Castle"

TPE gives you wings

For the latest highlight of PLAYMOBIL, the Great Dragon Castle, developers had to meet multiple challenges. One of those was the dragon, with a total of 8 injection moulding tools, of which 4 had to be designed for multi-component injection moulding.

To meet current safety regulations, parts of the dragon's body that could potentially cause injuries, had to be "defused" by the use of thermoplastic elastomers (TPEs).

But the selection of the materials was just not that simple. Since the body of the dragon is made of ABS, the soft materials for the spiky back and the claws of the dragon, had to be adhesion-modified for this thermoplastic material.

The PLAYMOBIL developers found the right answers at PTS MARKETING- & Vertriebs - GmbH in Adelshofen-Tauberzell, who got the adhesion-modified grades of the PTS-THERMOFLEX-A1/B family (TPS) in their portfolio.

Due to the high polarity of this material family, the adhesion to ABS is very high, but in case of the dragon wing, the large area in contact with the mould led to severe demoulding problems. On top of this, the soft component had to be highly transparent to implement the colour effects, required by the PLAYMOBIL design department.

After checking all technical properties Robert Banker, technical director at PLAYMOBIL gave the green light to try out a previously unknown hard/soft combination from PTS.

The materials specialists from Adelshofen developed an ABS-blend for the rigid elements of the wings (brandname PTS-CREABLEND-F) with adhesion to all standard TPS-grades (SEBS) and TPV-grades (EPDM/PP).

For the soft parts of the wings, a highly transparent TPS-grade
(PTS-THERMOFLEX) with a hardness of approx. 85 ShA was selected. The choice of a non-polar material that is by nature easy-to-process, was crucial to allow an automated production.

PTS-CREABLEND-F shows low warpage, high dimensional stability and chemical resistance. In simplified terms, this material combines the dimensional stability of ABS with the chemical resistance of Polypropylen and this should as well be interesting for the automotive industry and the electric appliances industry.

Furthermore, PTS-CREABLEND-F complies with all relevant provisions for food contact and consequently as well with the increasingly restrictive regulations at PLAYMOBIL.

For the wings of the PLAYMOBIL dragon, a new material combination of a special ABS-blend and a TPS is used.

04.08.08

Since 2004, the PTS Group has been working on the development of special semi-aromatic, electroplateable polyamides and adhesion-modified TPS or TPV grades, which can be processed into complex hard/soft components.

Thermoplastic elastomers such as these must be able to withstand electroplating baths without damage and form an adhesive bond with the pre-injection moulded part, so that no electroplating solution can penetrate.

For the soft component, adhesion-modified TPS or TPV grades are suitable. TPV has a particularly attractive matt finish after electroplating.

Only filler-free materials are suitable, since electroplating bath acids react with TPEs containing chalk. This not only contaminates the electroplating bath but leads to visible chemical attack on the surface of the soft component.

For the hard component, designers can choose from a range of special reinforced polyamides with low warpage tendency, e.g.:

DURAMON semi-aromatic, easyflowing polyamides, mineral-reinforced, low-
warpage, with an attractive finish
DURAMIDR semi-aromatic, easyflowing polyamides, 30 – 60% GF, low-
warpage, with an attractive finish
PTS-CREAMIDR-S special highly reinforced polyamides, low-warpage, with an attractive
finish, 30 – 60% GF

These high-performance polyamides with glass-fibre reinforcement or – for extremely low warpage – special mineral fillers can be used to produce hard/soft components for electroplating, preferably in combination with PTS-UNIPRENE (TPV). After injection moulding, the parts can then be processed into high-quality applications in the “chrome design” sector without any special covering being required on the soft component. Typical applications include:

- control knobs for the electrical and household appliance industries
- knobs for car radio or navigation equipment
- chrome plates with a soft sealing edge
- electrical and household appliances with soft handles

Self-extinguishing, radiation-crosslinkable, glass-fibre-reinforced polyamides – free from red phosphorus and halogens

Glass-fibre-reinforced and mineral-filled, radiation-crosslinkable polyamides, including grades flame-retardant-modified with red phosphorus, have been state-of-the-art for a long time.

However, the self-extinguishing grades of these materials have previously had the limitation of only being available in phosphorus red-brown or black.

The following pyramid chart shows how radiation-crosslinkable polymers, mainly polyamides, are upgraded to a higher performance level by irradiation.

Until now, it has not been possible to produce reinforced, self-extinguishing, radiation-crosslinkable materials in all colours.

PTS has therefore developed a new family of PA66 grades with glass or glass/mineral fillers, e.g.

These materials make it possible to produce HT components for thermal peaks way above the previous melting point and components suitable for lead-free soldering.

The green contact bridge is tested with the crosslinking tester (e.g. using a 2 mm test point at 350°C for 10 s with a test load of 1 kg). The radiation-crosslinked component withstands this test without any penetration, while in the case of the non-crosslinked component, the test point immediately penetrates right to the stop.

PTS-THERMOFLEX-B: new TPS base materials with excellent cost/performance ratio

PTS has developed a complete series of filled and unfilled PTS-THERMOFLEX-B grades, suitale for consumer products and applications in the automotive industry.

The PTS-Group introduces a new TPV-material on a styrol basis, featuring best compression set values.

The specific feature of this family of materials is the dynamic crosslinking of the middle and endbock what leads to the best elastic properties of all currently known TPE's.

The following diagram shows that even long-term compression set values - e.g. 1000h /120°C - are still in the range of 35%.

Starting mid-year 2006, PTS has taken over the distribution of the highly transparent, impact resistant PANLITE polycarbonate materials.

The PTS subsidiary CPP Creative Polymers produces polycarbonate specialities, coloured grades and glass-fibre reinforced materials under the brandname PTS-CREALON.

PTS has developed low-warp, semi-crystalline polyamides under the name PTS-CREAMON-B3H2M6* and many similar grades, which combine the dimensional stability of amorphous materials with the property spectrum of semi-crystalline products.

This product family was developed for low-warp automobile housing parts. The following graph shows the low warpage tendency of this family in comparison with glass-fibre-reinforced materials.

CMID = abbreviation for PTS-CREAMID, PA glass-fibre-reinforced
CMON = abbreviation for PTS-CREAMON, PA mainly mineral-reinforced

CMID-B3H2G10: PA 6, heat stabilisation, 50% glass fibre
CMID-B3H2G6: PA 6, heat stabilisation, 30% glass fibre
CMID-B3H2G5: PA 6, heat stabilisation, 25% glass fibre
CMON-B3H2WG33: PA 6, heat stabilisation, 30% mineral/glass fibre
CMON-B3H2WM51: PA 6, heat stabilisation, 30% mineral fibre
CMON-B3H2WM62: PA 6, heat stabilisation, 40% mineral fibre
CMON-B3H2M6: PA6, heat stabilisation, 30% special-mineral

These grades, too, are not based on standard polyamide 6.6 but on materials that contain reactive groups. They therefore have much better crosslinking properties and make it possible to achieve considerably higher degrees of crosslinking than standard materials.

PTS has launched a comprehensive range of special impact-resistant polypropylene materials with up to 40% reinforcement.

These materials are positioned between standard PP and long-glass-fiber-reinforced PP.

Their notched impact strength exceeds that of glass-fibre-reinforced polyamide in many cases.

Polyamide 11 and polyamide 12 are key materials for automotive hoses (hydraulic, fuel and water hoses).

In comparison with PA6 and PA6.6, these materials have a near-perfect property spectrum with their only weakness being a relatively low melting point.

Through radiation crosslinking, the heat resistance of these materials can be considerably increased.

This completely new TPE family has hardness values from 5 Shore A upwards. At 80°C the "soft" grades in this family have about twice the ultimate tensile strength of the previously used high-molecular-weight SEBS grades.

Grades in the medium hardness range around 60 Shore A still have 50-60% higher strength at 80°C.

The entire product family is odourless and meets all automotive interior specifications.

PTS can supply foamable TPE materials with hardness values from 5 Shore A upwards for extrusion of hoses and profiles and for injection moulding applications. Specific densities of 0.3 g/cm3 can be achieved in extrusion.

TPE-V grades (dynamically crosslinked EPDM/PP) from 25 Shore A upwards can be supplied immediately.

These products have very good flowability, low inherent colour and excellent elastic properties.

Adhesion-modified TPE-V materials with very good compression set at up to 100°C are available immediately from PTS for PA, PC, PMMA, POM, PBT, PC/ABS-Blends and ABS.