CREATING TOMORROW’S SOLUTIONS STRE NGTH WITH HDK®.

PYROGENIC SILICA | ADHESIVES

HDK® – THE PYROGENIC SILICA WITH PERSONALIZED SERVICE EXPERIENCE COUNTS

WACKER has produced pyrogenic silica Properties of HDK®: under the brand name HDK® for over • Synthetic, inert inorganic additive 50 years. Our integrated production • Neutral in color system, statistical process control, • Migration-resistant and highly efficient reactor dynamics • Thermally stable combine to make an exceptionally • Non-hazardous pure pyrogenic silica that offers high performance. HDK® is made by hydro- Benefits of HDK® in Adhesives: lysis of chlorosilane in an oxyhydro- • Highly effective rheology control gen flame. The process yields highly • Stable viscosity during storage branched aggregates, which are the • Controlled anti-sag behavior basic building block of our pyrogenic • Chemical inertness in various reactive silica. These form weakly bound ag- systems glomerates upon cooling. HDK® made • Effective tuning of mechanical in the flame reactor is hydrophilic. By properties post-treatment in a second reactor, we are able to offer hydrophobic HDK® grades, which are key to rheology control in polar systems.

How HDK® Works HDK® has an exceptionally high surface- area-to-mass ratio. This enables many particle interactions in liquid formulations and helps build a three-dimensional phys- ical network. This network is the basis for the rheology control HDK® provides. Ob- taining optimal rheology for your adhe- sive depends on getting the specific sur- face area just right and selecting the What HDK® grades will correct hydrophilic or hydrophobic HDK® yield the best results in your grade. Our broad portfolio provides the formulation? Just get in ideal solution for nearly any formula. touch with us, and we will gladly advise you.

Germany: toll-free number, international +800 6279 0800 USA: toll-free number: +1 888 922 5374 (+1 888-WACKER 4 U) China: +86 21 6130-2000

2 OPTIMIZE PERFORMANCE

Superior Rheology Control in Adhesives

Adhesives require good rheology control during manufacture, storage, and processing. The rheological properties of adhesives can be adjusted using suitable HDK® grades. Adding HDK® to an adhesive formulation increases the viscosity of the liquid phase, influencing shear thinning and thixotropic flow behavior. In general, HDK® grades with a larger specific surface area yield more pronounced rheological effects, while grades with a smaller specific surface area are easier to disperse. Hydrophobic HDK® grades are typically used for polar adhesives formulations. The chemical inertness of hydro- phobic HDK® in polar, reactive resins allows for excellent storage stability. Hydrophilic HDK®, on the other hand, enables excellent rheology control of non-polar adhesives formulations and is often suitable for use even under high pH value conditions.

Suitable Viscosity during Processing, components from settling. The viscosity adhesive has been applied to a sub- Storage, and Application at rest is influenced by the grade and strate, the HDK® network reforms (thixot- Once incorporated and dispersed in an amount of the added silica. When shear ropy). This leads to a fast recovery of vis- adhesive formula, the interacting HDK® forces are applied during the processing cosity, effectively avoids sagging, and aggregate particles form a shear-sensi- of the adhesive, the branched network ensures your adhesive will stay where tive three-dimensional network. During breaks up and the viscosity decreases you want it while curing. storage, the network formation increases (shear thinning). This allows for easy the formulation’s viscosity and prevents processing of the adhesive. After the

How the Three-Dimensional HDK® Network Works

Network formation Isolated aggregates Rebuild of network at rest under shear after shear Viscosity

High viscosity during storage Reduction of viscosity Recovery of viscosity

Storage Application Curing

Time

HDK® is a registered trademark of Wacker Chemie AG. 3 A KEY COMPONENT: HDK® IN ADHESIVES

Rheology Control in Bonding Pastes

Wind turbine bonding pastes based on epoxy and vinyl ester resins are applied in thick beads onto rotor blade half shells. Adding HDK® to bonding paste formulas enables optimal rheology control in order to meet the demanding requirements for sag resis- tance. The pronounced thixotropy and shear-thinning effect provided by HDK® allows easy processing of the adhesives components even at high silica loading levels. More- over, HDK® increases the viscosity of adhesives components during storage and pre- vents ingredients from settling.

Composition of Bonding Paste Component 1 Resin Bisphenol A/F-based Reactive diluent Glycidylether-based Filler Mineral filler, others Aspirator (if applicable) Foam-breaking polymers/polysiloxanes Toughener e.g. GENIOPERL® P52 Rheology additive HDK® H18, HDK® H21, HDK® H17 Component 2 Amine hardener Polyaminoamide/IPDA/polyetheramine Rheology additive HDK® N20

TIP Add the highly hydrophobic grade HDK® H18 to epoxy adhesives for high rheological impact and excel- lent storage stability. Typically, the concentration level of HDK® in resin components should be 8–10% by weight. HDK® H21 and HDK® H17 are excellent alternatives and are even easier to incorporate.

4 Properties of HDK® Grades in Epoxy-Based Systems

® Depending on your individual require- Sag Resistance vs Incorporation Time for Different HDK Grades ments, WACKER offers various grades of HDK® H18 HDK® that perform differently in epoxy- based systems. Due to its high degree of High HDK® H21 surface modification, HDK® H18 provides the highest storage stability and sag re- sistance to polar adhesives. HDK® H21 HDK® H17 combines excellent anti-sag properties adhesive of resistance Sag with short incorporation times into resin components. HDK® H17 displays well balanced features and is particularly easy to disperse. HDK® H13L Low

Short Long Incorporation time into resin component

Sag resistance properties and incorporation time of HDK® in epoxy-based formulations

® Hydrophobic HDK grades ensure low viscosity Storage of HDK® H18 vs HDK® H13L vs HDK® H20 in an Epoxy Resin during application, high viscosity and sag resis- tance at rest, and anti-settling during storage. 8000

7000 Viscosity [Pas] 6000

5000

4000

3000

2000

1000

0 HDK® H18 HDK® H13L HDK® H20 System: epoxy resin with 8 wt% HDK® Dispersing equipment: dissolver Viscosity measured at shear rate 0.1 s –1

1d 7d 30d

HDK® H18 has a very high degree of surface modification. Compared to less hydrophobic silica grades HDK® H18 combines excellent thickening performance and storage stability in epoxy-based formulas.

5

HDK® H18 for Maximal Sag Resistance

® HDK® H18 achieves high viscosity in vinyl Correlation of Sag Resistance and HDK Dosage in Vinyl Esters esters at low dosages. At the same time, the high hydrophobicity as well as the 700 large particle surface area provide good 600 thixotropy. These characteristics make HDK® H18 a superior choice over less 500 Sag resistance [μm] Sag hydrophobic products when high sag 400 resistance is a deciding requirement. 300

® HDK H21 for Easy Dispersion 200 HDK® H21 is a silica for use in highly polar systems including vinyl ester resins. The 100 polysiloxane treated product displays 0 superior processing and performance 1 1.5 2 2.5 3 properties and has been designed to Dosage HDK [wt%] provide easy dispersion and excellent HDK® H18 HDK® H13L rheology control. HDK® H18 outperforms less hydrophobic silicas based on smaller particle surfaces with regard to the sag resistance of vinyl esters.

Optimal Thixotropy and Processing in Vinyl Ester Resins with HDK® H21

400

350

Viscosity [Pas] 300

250

200

150

100

50

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Rheology – Shear Rate Sweep – 24 hrs. 60 sec. at 1 s-1, 10 s-1, 199 s-1, 1 s-1 intervals

HDK® H21 Competitive Siloxane Treated Grade

HDK® H21 exhibits superior rheological properties, a very high thixotropic effect, and is easy to incorporate.

6

HDK® Pyrogenic Silica for Chemical Anchors

Chemical anchor fasteners based on Optimal Rheology Control with HDK® vinyl esters and two-component epoxy Highly hydrophobic and chemically inert formulas are polar adhesives that secure grades, such as HDK® H18, HDK® H21, mechanical anchors such as bolts, rods, and HDK® H17, provide excellent and dowels in concrete and masonry thixotropy and effectively enable easy construction, and help support heavy processing and maximal sag resistance. loads. As a rheology additive to chemical HDK® is very stable in polar systems, anchor formulations, HDK® prevents sag- ensuring extended product shelf life. ging in the uncured adhesive so it does not flow out of the drilled hole.

Vinyl-Ester-Based Adhesive Resin Vinyl ester Rheology additive HDK® H18, HDK® H21 Filler Quartz sand/cement Adhesion promotor Functional alkoxyalkylsilane Peroxide curing agent e.g. MEKP

TIP Use HDK® H21 if the dispersion of other polydimethylsiloxane-treated silica grades is challenging.

7 ® Stability in High-pH Conditions Thixotropy over Storage Time – HDK H20RH vs Siloxane-Treated Silica in High-pH Conditions ® Hydrophilic silica such as HDK N20 is –1 used to develop a good rheological 35 profile in amine components of epoxy 30 and 500 s adhesives, but it often requires high silica –1 loadings. Depending on the formula’s 25 polarity, hydrophobic siloxane-treated 20 silicas may give a better rheological im- pact but are not sufficiently stable in 15 ® high-pH conditions. HDK H20RH has an 10 alkylsilane-modified particle surface Thixotropy index at 0.5 s which is stable in the amine component 5 and leads to a pronounced thixotropy, 0 even at lower silica loadings. 1d RT 7d 40°C 28d 40°C

HDK® H20RH Siloxane-treated silica

With HDK® H20RH, the thixotropic behavior of an amine mixture can be maintained during storage, whereas siloxane-treated grades are less suitable for high-pH value formulations.

TIP Correlation of Dosage and Viscosity for HDK® H20RH and HDK® N20 in IPDA

® Use HDK H20RH in the amine com- 100 ponent for better thixotropy at lower 90 dosages as an alternative to a hydro- 80

philic silica. In contrast to siloxane- Viscosity [Pas] treated silicas, HDK® H20RH is stable 70

in high-pH conditions. 60

50

40

30

20

10

0 1 2 3 4 5 6 1 8 HDK® dosage [%]

HDK® H20RH HDK® N20

HDK® H20RH allows for reduced dosages in medium to high polar amines such as isophorone diamine. 8 Rheology Control in Structural Adhesives

Structural adhesives are used in the con- struction of transport vehicles, for weight reduction purposes, improved crash per- formance, and durability. Applications include the bonding of parts that are dif- ficult to access, bonding materials that are non-weldable and/or heat-sensitive, and joining metallic with plastic surfaces. Epoxy adhesives are well known for their excellent mechanical properties, durability over a wide temperature range, and adhe- sion to many materials. Two-component polyurethane adhesives are excellent for joining composite materials. They combine strength and stiffness at high elongation values. Hydrophobic HDK® grades such as HDK® H18 and HDK® H21 ensure highest sag resistance in epoxy- based adhesives where standard hydrophobic grades fail. Adjusting the rheology of structural adhe- sive components with hydrophobic HDK® plays a decisive role in terms of process- ability, anti-sag properties, and storage stability.

TIP Shear Thinning with 5% HDK® Dosage in Isocyanate Component Efficient rheology control of isocya- nates requires hydrophobic HDK®. 700 ® ® Suitable grades are HDK H21, HDK 600 ® H18, and HDK H17. For most pro- Viscosity [Pas] nounced thixotropy and shortest 500 ® incorporation time, HDK H21 is 400 recommended, while HDK® H18 achieves maximal storage stability. 300

200

100

0 Without HDK® 5% HDK® H21 5% HDK® H18 5% HDK® H17

0.1 s –1 10 s –1

HDK® H21 provides superior rheological properties in an aromatic isocyanate component at 5% dosage.

9

HDK® Pyrogenic Silica for Wood Adhesives

® ® One-component polyurethane adhesives Moisture Absorption HDK H18 vs HDK N20 are widely used in applications requiring 10 increased strength and flexibility. They 9 provide high water and temperature re- sistance, and are particularly suitable for 8 adhesion to wood, ceramics, stone, and 7 metal. One-component moisture cure 6

polyurethanes require the absence of [%] dm absorption Moisture 5 moisture during storage. Highly hydro- phobic HDK® grades do not absorb 4 moisture and ensure good stability as 3 well as a long shelf life of the adhesive. 2 The highly hydrophobic grades HDK® 1 H21, HDK® H18, and HDK® H17 achieve the strongest rheological effect in one- 0 5 10 15 20 25 30 35 40 45 50 component polyurethane adhesives. Time [h] Less hydrophobic grades, such as HDK® H15, improve lap shear strength. HDK® N20 HDK® H18 Conditions: 88% rel. humidity, 23°C, 48-hr. exposure time The highly hydrophobic grade HDK® H18 does not absorb significant amounts of moisture, even in high- humidity environments and during long exposure times.

10

Superior Strength and Flexibility

Lap Shear Adhesion Strength 1-C PU with HDK®

1800

1600

1400

1200

1000 Lap shear adhesion strength [kPa] strength adhesion shear Lap 800

600

400

200

0 Without HDK® 3.5% HDK® H21 3.5% HDK® H18 3.5% HDK® H15

In one-component polyurethane adhesives, HDK® may increase lap shear strength (wood adhesion). Most pronounced effects are achieved with the semi-hydrophobic grade HDK® H15.

Elongation at Break with HDK® TIP Add hydrophobic grades such as 1.8 HDK® H15 and HDK® H20 to one-

1.6 component adhesive formulations to achieve the highest lap shear 1.4 strength at high elongation values.

Elongation at break [%] 1.2

1.0

0.8

0.6

0.4

0.2

0 Without HDK® 3.5% HDK® H21 3.5% HDK® H18 3.5% HDK® H15

Adding HDK® to one-component polyurethane formulas increases the elongation at break.

11

HDK® Pyrogenic Silica for Transparent Adhesives

Transparency is a key feature of many STP-E30-Based Formula ® silane terminated polyether-based adhe- Polymer GENIOSIL STP-E30 sives and sealants. Besides optimizing Rheology additive Hydrophobic HDK® ® rheological properties, HDK® also im- Moisture scavenger GENIOSIL XL10 ® proves mechanical properties in the Plasticizer Hexamoll DINCH ® cured formulas. Since other bulking and Adhesion promotor GENIOSIL GF96 reinforcing fillers are not used in these ® clear formulas, it is important to find the Shear Thinning with HDK in STP-E30 right HDK® dosage for an optimal bal- 9000 ance between the desired rheological impact and mechanical properties. 8000 Viscosity [Pas] 7000 Hydrophobic HDK® grades based on ® large surface areas such as HDK H18 6000 and HDK® H20 achieve strong thixotropy even at lower dosages. In contrast, the 5000 smaller particle surface area products 4000 HDK® H13L and HDK® H15 allow for highest loading levels, improving the 3000 physical properties of the cured formula. 2000

1000

0 10% HDK® H13L 10% HDK® H20 10% HDK® H15 10% HDK® H18 20% HDK® H13L

0.1 s –1 10 s –1

HDK® H20 and H18 cause the strongest rheological impact in a GENIOSIL® STP-E30-based formula at a loading level of 10%. Even higher loading levels could be easily achieved with less hydrophobic grades, particularly HDK® H13L.

TIP Use HDK® H13L to realize high silica loading levels and excellent me- chanical properties of your cured transparent formula.

12

HDK® H2000 for Transparent STP-E Formulas

HDK® H2000 is a high-density silica STP-E35-Based Formula ® grade that has very low rheological im- Polymer GENIOSIL STP-E35 pact in spite of its highly hydrophobic na- Rheology additive HDK® H2000 ® ture. This allows for HDK® loading levels Moisture scavenger GENIOSIL XL10 exceeding 25% in transparent STP-E for- Plasticizer PPG 2000 ® mulas for outstanding tensile strength Adhesion promotor GENIOSIL GF91 ® while maintaining good elongation at Catalyst TIB KAT 216 break. Additionally, HDK® H2000 dispers- es easily and contributes to transparency. Tensile Strength and Elongation at Break of an STP-E35-Based Formula ] 2

9 350 [%] Benefits: [N/mm • Highly hydrophobic 8 300 • High bulk density 7 • Easy to disperse 250 • Allows for high loading levels 6 • Improves tensile strength 200 • Enables highest transparency 5

4 150

3 100 2

50 1

0 0 15 20 25

Loading level HDK® H2000 [% m/m]

Tensile strength Elongation at break

The tensile strength of STP-E-based formulas increases significantly with the HDK® H2000 loading level while elongation at break is not much affected by the HDK® concentration.

13 BRINGING SUPERIOR SERVICE CLOSER TO YOU

Expanding our Global Presence

New Capacity in North America Optimal Packaging, single bags are removed, it is advisable WACKER’s state-of-the-art facilities in Optimal Performance to protect the remaining or individual bags Europe and China produce a variety of In order to ensure maximum effectiveness either by wrapping them in plastic or pyrogenic silica grades, including nutri- of your products and formulations, we adopting other appropriate measures. tional and pharmaceutical products. offer various forms of packaging to suit Furthermore, our newest production plant your logistics and workflow requirements. Big Bags is set to go on-stream in Charleston, TN, Packaging size, effective moisture protec- The big bag solution is available for most USA, in 2019. With an annual capacity of tion, and your specific requirements are HDK® grades. Big bags are made of about 13,000 metric tons, the new facility important factors in determining the opti- woven polypropylene and are suitable for will be a key component of the Charleston mal HDK® packaging for your productivity. 150 to 200 kg of product, depending on site, which produces polysilicon for the bulk density. Big bags are delivered on solar and semiconductor sectors. By inte- Pallets with Paper Bags pallets, shrink-wrapped with a polyethyl- grating the polysilicon and HDK® pro- HDK® is available in multilayer, valved ene film as a safeguard against moisture. duction systems, WACKER can achieve paper bags, which can accommodate maximum flexibility, less waste, and 5 to 20 kg of product, depending on bulk We also provide advice on how to handle enhanced efficiency. This facility will open density. The bags are delivered on pallets the material and, in particular, how to up new avenues for customers seeking that are shrink-wrapped with a polyethyl- fluidize and unload big bags. an on-shore supplier in North America. ene film for moisture protection. If the shrink film is damaged accidentally or Please contact us for further information.

Pallets with paper bags Big bag

14 EXPERTISE AND SERVICE NETWORK ON FIVE CONTINENTS EXPERTISE AND SERVICE NETWORK ON FIVE CONTINENTS

• Sales offices and production sites, plus 21 technical centers, ensure you a local presence worldwide.

WACKER is one of the world’s leading Spanning the globe with 4 business wide in the development of products and most research-intensive chemical divisions, we offer our customers highly- tailored to regional demands, supporting

companies, with total sales of €4.92 billion. specialized products and comprehensive •them Sales during offices andevery production stage ofsites, their plus complex Products range from silicones, binders and service via 23 production sites, 21 technical production21 technical centers,processes, ensure if yourequired. a local presence polymer additives for diverse industrial competence centers, 13 WACKER WACKERworldwide. e-solutions are online services sectors to bioengineered pharmaceutical ACADEMY training centers and 50 sales provided via our customer portal and as WACKERactives and is hyperpureone of the siliconworld’s for leading semi- Spanningoffices in theEurope, globe Northwith 4and business South America, wideintegrated in the process development solutions. of products Our custom - andconductor most research-intensive and solar applications. chemical As a divisions,and Asia –we including offer our a presencecustomers in China.highly- tailoreders and businessto regional partners demands, thus supporting benefit companies,technology leader with total focusing sales on of sustainability,€4.92 billion. specializedWith a workforce products of some and comprehensive13,800, we see themfrom comprehensiveduring every stage information of their and complex reliable ProductsWACKER range promotes from productssilicones, andbinders ideas and serviceourselves via as23 aproduction reliable innovation sites, 21 technicalpartner productionservice to enable processes, projects if required. and orders to be polymerthat offer additives a high value-added for diverse industrial potential to competencethat develops centers, trailblazing 13 WACKERsolutions for, WACKERhandled fast, e-solutions reliably and are highly online efficiently. services sectorsensure that to bioengineered current and future pharmaceutical generations ACADEMYand in collaboration training centers with, our and customers. 50 sales providedVisit us anywhere, via our customer anytime aroundportal and the as activesenjoy a betterand hyperpure quality of lifesilicon based for onsemi energy- officesWe also helpin Europe, them boost North theirand ownSouth success. America, integratedworld at: www.wacker.com process solutions. Our custom- conductorefficiency and and solar protection applications. of the climate As a andOur technicalAsia – including centers a employpresence local in China. ers and business partners thus benefit technologyand environment. leader focusing on sustainability, specialistsWith a workforce who assist of some customers 13,800, world we see- from comprehensive information and reliable WACKER promotes products and ideas ourselves as a reliable innovation partner service to enable projects and orders to be that offer a high value-added potential to that develops trailblazing solutions for, handled fast, reliably and highly efficiently. ensure that current and future generations and in collaboration with, our customers. Visit us anywhere, anytime around the All figures are based on fiscal 2017. enjoy a better quality of life based on energy We also help them boost their own success. world at: www.wacker.com efficiency and protection of the climate Our technical centers employ local and environment. specialists who assist customers world- e_single page_A4_2017.indd 1 27.03.18 09:13

All figures are based on fiscal 2017. 15

e_single page_A4_2017.indd 1 27.03.18 09:13 Wacker Chemie AG Wacker Chemical Corporation Wacker Chemicals (China) Co., Ltd. Hanns-Seidel-Platz 4 3301 Sutton Road Bldg. 3, 1535 Hongmei Road 81737 Munich, Germany Adrian, MI 49221-9397, USA Caohejing Hi-Tech Park Tel. +49 89 6279-1741 Tel. +1 888 922 5374 Shanghai 200233, P.R. China Toll-free number, international: NAFTA Region – Canada, Mexico, and USA Tel. +86 21 6130-2000 +800 6279 0800 Toll-free number: Fax +86 21 6130-2500 [email protected] +1 888 922 5374 (+1 888-WACKER 4 U) [email protected]

www.wacker.com/hdk [email protected] 11.14 7679e/03.19/replaces www.wacker.com/socialmedia

The data presented in this brochure are in accordance with the present state of our knowledge but do not absolve the user from carefully checking all supplies immediately on receipt. We reserve the right to alter product constants within the scope of technical progress or new developments. The recommendations made in this brochure should be checked by preliminary trials because of conditions during processing over which we have no control, especially where other companies’ raw materials are also being used. The information provided by us does not absolve the user from the obligation of investigating the possibility of infringement of third parties’ rights and, if necessary, clarifying the position. Recommendations for use do not constitute a warranty, either express or implied, of the fitness or suitability of the product for a particular purpose.