Platy and fiber shaped fillers are well-known for effective reinforcement of plastics. However, the downside has always been loss of impact resistance because such particles act as stress concentrators (flaws). DRAGONITE™ brand Halloysite breaks that paradigm. DRAGONITE is a natural clay consisting of hollow tubules. These tubes are high aspect ratio and thus modulus and yield strength are boosted significantly and, unlike traditional fillers, DRAGONITE also retains and, in certain cases, improves impact resistance and elongation to break due to its fine particle size and dispersibility.   

Applied Minerals has tailored grades of its DRAGONITE product line specifically for the polymer market. Through ultra-high purity and carefully controlled particle size, maximum performance is assured.

Click below to see the benefits of DRAGONITE in a wide range of resins

Overview

Polypropylene


The Advantages of DRAGONITE-HP in PP include (1 wt% loading)

Mechanicals Improvement

  • Modulus increased by 20-25%
  • Strength increased by >20%
  • Impact resistance increased by 40% (notched Izod)
  • Enhanced mechanicals provide ability to downgauge for thinner/lighter parts

Cycle Time Reduction

  • Faster production through up to 25% lower cycle time by increasing the onset of cyrstallization of PP by approximately 8°C
  • Extra savings in cycle time possible through downgauging

Other Benefits

  • Improvement to creep resistance, surface hardness and HDT / Vicat softening temperature

Applications

  • Effective in all processes including injection molding, blow molding, thermoforming, rotomolding, extrusion and compression molding
  • Automotive parts where good mechanicals, light weight, surface finish and recyclability are key
  • Household appliances for material cost reduction and cycle time benefits
  • Electrical parts where halogen-free flame retardance is specified
  • Boost mechanicals while retaining scratch resistance for aesthetic parts

DRAGONITE HP for polypropylene is available either in powder form or as a 40% masterbatch concentrate to ensure proper dispersion and accurate dosing.


In PP homopolymer Dragonite-XR delivers great properties at low density. Reinforcement is obtained, as indicated by the improvement in flexural strength and modulus, even without the use of coupling agents. This is attributed to the high aspect ratio of the filler combined with good wetting of the filler surface. Further evidence of excellent dispersion can be seen in the impact resistance, which is preserved at all loadings. The ability of DRAGONITE-XR to provide attractive properties at high loadings makes it an appealing alternative to traditional mineral flame retardants.

Polyethylene


The Advantages of DRAGONITE-HP in PE include (1 wt% loading)

Mechanical Improvements

  • Reduced CTE, shrinkage and warpage
  • Increased modulus by 20-30%
  • Increased strength by 15-20%
  • Retention of impact resistance (unusual for filled polymers)
  • Enhanced mechanicals provide ability to downgauge for thinner/lighter parts

Cycle Time Reduction

  • Cycle time reduction up to 30% seen for injection molded and compression molded parts
  • Extra savings in cycle time possible through downgauging

Other Benefits

  • Fixes issues with sink-marks, CTE, shrinkage and warpage while retaining good surface finish

Applications

  • Injection molded, blow molded, thermoformed, extruded and compression molded parts of all types from bottles to wire and cable
  • PE film giving improved bubble stability, good transparency and improved mechanical properties

DRAGONITE-HP for polyethylene is available either in powder form or as a 40% masterbatch concentrate that ensures proper dispersion and accurate dosing.


DRAGONITE-XR performs as loadings are increased and around 60 weight % it imparts halogen free flame retardance on top of reinforcement through the modulus and strength benefits.

Nylon 6

The Advantages of Dragonite-HP in Nylon 6 include (1 wt% loading)

  • Modulus increased by 20%
  • Strength increased by >10 %
  • Elongation to break retained at very high level
  • Good processability even at 30 weight % Halloysite

In addition there is evidence that DRAGONITE-HP results in modification of the crystal phase forming type morphology.

Applications

  • The hollow tubes can be loaded with oil to give a self-lubricating material with controlled release of lubricant over time
  • DRAGONITE-HP can be incorporated in thermoplastic nylon or in the monomer when making cast nylon parts

Higher levels of Dragonite-XR grade result in substantial reinforcement as seen by the simultaneous improvement in modulus and strength. Unlike traditional reinforcing agents, Dragonite-XR enables good retention of impact resistance and low weight because of the low density of the filler. At even higher loadings a V0 flame retardance rating is possible.

Polylacticacid (PLA)

Polylactic acid and its copolymers have attracted a lot of attention because it is one of the few thermoplastic materials derived from a natural, sustainable and biodegradable monomer. PLA is already commercial in packaging film but its properties must be improved if other applications such as injection molded parts and fibers are to be realized.

The Advantages of DRAGONITE-HP in PLA include

As an additive for injection molded PLA (2 wt% loading):
  • Good mechanical properties attributed to good dispersion and a high level of interaction between the filler and polymer
  • Modulus increased from 0.7 to 2.25 GPa (+220%) and ultimate tensile strength increased from 29.2 to 43.2 MPa (+48%).
  • Elevated the mechanical properties of PLA to be competitive with polystyrene and other popular thermoplastic materials.
  • Significantly increased the stiffness of PLA at elevated temperatures (HDT)
  • Full retention of impact resistance
Incorporation into poly(lactic-co-glycolic acid) to make electrospun fibers:
  • Modulus, ultimate tensile strength and elongation to break were all improved
  • No detrimental effects on the fiber spinning operation due to excellent clay dispersion

It is especially fitting to use DRAGONITE-HP, a natural, biocompatible clay, as an additive to elevate the performance of PLA and other naturally derived polymers.

For higher addition levels, Dragonite-XR is the preferred solution bringing not only further reinforcement through improvements to modulus and strength but also with the added advantage of flame retardance up to V0 level. See the PP and PA6 sections for examples of Dragonite-XR performance.

Elastomers

Recommended DRAGONITE product grade:


 

 
 

The elastomers market is the largest single user of high performance fillers like carbon black and silica ($5 Billion USD annually). High surface area grades are used as these facilitate processing of the elastomers and also raise the mechanical properties.

DRAGONITE, as a high surface area silicate type filler, would be expected to show promise in elastomeric systems and that has indeed been found to be the case.

The Advantages of Dragonite in Elastomers include

Incorporation into EPDM (at 100 phr)
  • Tensile strength increased by >800%
  • 100% modulus increased by almost 300%
  • Elongation to break increased by almost 300%
  • UL-94 flame retardance rating of V0

Incorporation into Natural Rubber
  • Excellent dispersion leads to good modulus, strength and elongation to break
  • Concluded to be more effective reinforcement than silica
  • Onset of thermal degradation as measured by TGA, improved by 64°

Fluoroelastomers

 

 


 

Recommended DRAGONITE product grade:


 

The Advantages of Dragonite in Fluoroelastomers include

  • Substantial increase in strength and modulus with full retention of elongation to break
  • No shift in glass transition temperature
  • Increase in thermal stability

 

Epoxy Resins

 

Recommended DRAGONITE product grade:


The superior performance seen in thermoplastics and elastomers is mirrored in thermoset materials. In epoxy resins, numerous articles have reported excellent results. Halloysite improves modulus and strength as one would expect for a high aspect ratio filler. Just 5 weight % Halloysite improved the interlaminar shear strength (ILSS) by 25% in carbon fiber reinforced Epon Resin 828 cured with MDA. Toughness was significantly improved at the same time.

In another study, adding just 2.3 weight % Halloysite improved impact resistance by an astonishing 400%. These benefits are of particular interest in the aerospace industry where light, durable carbon fiber reinforced epoxies dominate.

Rigid PVC





Recommended DRAGONITE product grade


 

DRAGONITE improves the properties of rigid PVC. Again, true reinforcement is seen as evidenced by an increase in both strength and stiffness. Even more impressive is that no loss in either impact resistance or elongation to break is seen. In fact, the virgin PVC failed in a brittle mode whereas all samples with DRAGONITE added became ductile.

Transparent Films

Packaging is one of the major applications for polyolefins and other thermoplastic materials. Transparent films in particular are in demand. Due to the huge volumes of material used and intense competition, there is a continual drive to higher performance enabling down-gauging and ultimately, reduced materials cost. Traditional fillers have  intrinsic limitations including loss of transparency, and difficulties in controlling particle size distribution and dispersion to the degree needed to enable continuous commercial production.

The Advantages of DRAGONITE-HP in Films Include

  • Provides for better mechanical properties even at low loadings
  • Disperse readily in thermoplastics 
  • Provide a further boost in properties during monoaxial or biaxial orientation of the film
  • Improved bubble stability through increased melt strength

Transparent films containing 10 or 20 weight % DRAGONITE-HP have been produced. It has also proven possible to load the tubes with liquid actives which then release at a controlled rate. Applications for that include scented packaging and incorporation of natural oils that act as insecticides.

Other Polymers

DRAGONITE has also proven effective in a wide range of other polymers including PET, PBT, Nylon 12 and PEEK.

Developments in several other polymers are ongoing.

 

Environmental/Recyclability

DRAGONITE is a natural material that allows for reduced energy consumption during part production as well as reduced plastics use through thin-walling enabled by the mechanical property improvements.

DRAGONITE is also recyclable. Customers are aware that fillers are often broken down during recycling operations whereby the extruder damages the particles and the mechanical properties fade with each successive recycling operation. A study using multiple successive extruder passes showed that DRAGONITE enables property retention when recycling because the particles are simply too small to be broken down by extrusion.

Frequently Asked Questions

Q - Will DRAGONITE cause wear on process equipment?
A - No. With a Mohs hardness of 2, Dragonite cannot cause wear.

Q - Are special processing conditions required?
A - We supply DRAGONITE predispersed in masterbatch concentrate to facilitate easy incorporation and handling. When using the DRAGONITE in powder form we can provide processing guidelines.

Q - Does the DRAGONITE contain any potentially hazardous impurities?
A - We are able to deliver a product of unrivaled purity, thus avoiding any such issues.

Q - Are there any extractibles that could leach out of a Dragonite containing product?
A - No, DRAGONITE is 100% mineral that is inert and insoluble so, unlike some other additives and nucleating agents, there are no migration, smell or taste issues.

Q - How will DRAGONITE affect color and surface finish?
A - Dragonite is a white powder, which when used in typical loadings is colorless. In fact transparent, colorless films are possible with 25 wt% loadings. Because the particles are small and well-dispersed, high gloss levels are possible.

Q - How will DRAGONITE affect density and part weight?
A - 1 wt% DRAGONITE has a negligible affect on density and allows you to thin-wall giving substantial weight savings

Q - Is Halloysite a new, unproven material?
A - No, Halloysite is a natural clay, identical in chemistry to kaolinite. Furthermore it has been used for decades in ceramics, catalysts and other common industries. The recent commercialization in plastics is due to the discovery and launch of the pure DRAGONITE material, leading to better properties.

Q - Many high-tech materials are expensive and only available in small quantities. Is that the case for your material?
A - Dragonite is available in industrial-sized quantities and is priced to offer a compelling value proposition.

Q - Is Halloysite registered under REACH?
A - According to REACH Article 2 7(b) and Annex V; point 7 of the REACH Regulation (EC) 1907/2006, natural minerals are exempt from registration.

Q – Do you sell surface treated grades or should I apply a surface treatment?
A – Multiple studies have shown that excellent dispersion and properties can be obtained without any surface treatment. Therefore we do not at present supply a treated grade. If you wish to modify the Dragonite we can supply information on the use of organosilanes and other additives.