Knowde Enhanced TDS
Identification & Functionality
- Chemical Family
- Polymer Name
- Technologies
- Product Families
- Chemical Composition
Synthetic rubber based on ester/MDI polyurethane.
Features & Benefits
- Labeling Claims
Applications & Uses
- Applications
- Cure Method
- Plastics & Elastomers End Uses
- Plastics & Elastomers Processing Methods
- Product Applications
- Millathane 26, because of its compliance with the FDA regulation for “Rubber articles intended for repeated use” (21CFR 177.2600), is used for various rubber parts in contact
- with wet and dry food. These include hose, gaskets, rollers and belting.
- Millathane 26 also finds used in non-food handling applications, including rollers, because of its hydrolysis resistance and good strength properties.
- The inherent hydrolysis resistance of polyether urethanes like Millathane 26 makes them more forgiving in steam autoclave cure processes than polyester grades.
Properties
- Appearance
- Pale to yellow solid bales
- Typical Properties
- Product Properties
- Vulcanizates based on Millathane 26 can be produced in hardnesses of approximately 45 to 99 Shore A (to 65 Shore D) and offer excellent strength properties and abrasion resistance.
- Being a polyether urethane, Millathane 26 gives compounds with excellent resistance to hydrolysis.
- Millathane 26vulcanizates show good heat resistance and compression set, and good oil resistance.
| Value | Units | Test Method / Conditions | |
| Specific Gravity | approx. 1.03 | — | — |
Regulatory & Compliance
- Certifications & Compliance
- Chemical Inventories
Technical Details & Test Data
- Processing Information
- Millathane 26 is processed by techniques which are common to the rubber industry. Compounds can be mixed on open mills or in internal mixers. The Premilled version, being in sheet form, may be easier to mill mix.
- Very often a compound can be mixed in one step including the vulcanization chemicals. Molded articles can be produced via compression, transfer or injection molding.
- Injection molding Millathane 26 provides very short cycle times, excellent flow and demolding and shows negligible mold fouling. Due to the peroxide vulcanization and its chemical base, Millathane 26 can not be cured in direct contact with open steam or hot air, and, hence, for applications like hose, its use is limited to inner liners unless the parts are protected during curing.
- Calendered sheets can be press-cured or roto- cured.
- Millathane® 26 Compounding
- Reinforcing Fillers
- Reinforcing fillers like precipitated silica or carbon black like N330 increase the mechanical strength of Millathane 26 compounds. Fumed silicas such as Wacker HDK N20 or Cabosil M-5 will give somewhat higher reinforcement than precipitated silicas and will give translucent cured compounds (depending on other ingredients).
- They also give compounds that have lower water absorption than precipitated silicas, and hydrophobic silicas, like Cabosil TS-720 and Wacker HDK H20, are even better in that respect.
- Clay, talc and calcium carbonate can also be used as fillers to modify properties and processing, but are less reinforcing than silicas and blacks. Silane coupling agents like Silquest RC-1, A171 or A172 will improve the tear strength and set properties of mineral filled/reinforced compound and are recommended to be added at about 2% of the mineral filler content.
- Plasticizers
- TP-95 (DBEEA) can be used for FDA-complaint formulations, up to 30% by weight in the formula.
- For non-FDA applications, Mediaplast NB-4 and Benzoflex 9-88SG can be used. The antistatic plasticizer Struktol AW-1 can be used to a limited extent, but may tend to bleed at levels over 10 parts.
- Process Aids
- Small amounts of process aids are normally used to prevent sticking to processing equipment and to improve flow during molding.
- Generally, about 0.2-0.5 phr of stearic acid is used along with 0.5-2 phr ofanother process aid such as Struktol WB222 or Vanfre AP-2 Special.
- A low molecular weight polyethylene like AC617A, added at 1-4 phr, gives good release for calendering and molding.
- Stabilizers/Antidegradants
- The addition of 0.5 - 1.0 phr of Irganox 1076 will significantly improve heat aging and is recommended for molding compounds, to eliminate “sticky flash”.
- Naugard 445, added at 0.5 - 2.0 parts, will provideeven better heat resistance than Irganox 1076, although it is not FDA-compliant.
- Curing Agents: Peroxides and Coagents
- Typical peroxides used are dicumyl peroxide and DBPH (2,5-dimethyl-2,5-di (t-butylperoxy) hexane), typically used at about 1.6 - 2.4 phr active peroxide (4-6 phr of 40% active).
- The use of coagents such as SR-350 (TMPTMA), triallyl cyanurate (TAC) and liquid polybutadiene (e.g., Ricon 154) increase the crosslink density and improve compression set. .
- Note that for FDA (21CFR177.2600) compliance, the amount of peroxide plus TAC cannot exceed 1.5% by weight, and SR-350 cannot exceed 3% by weight.
- High Hardness Compounds: Peroxide and Isocyanate Cures
- For high hardness compounds (>70 Shore A), high levels of silica or other fillers can be used although they increase viscosity significantly.
- The liquid methacrylate SR350 will increase hardness and can be used in combination with reinforcing fillers.
- Liquid polybutadiene (e.g., Ricon 154) and high styrene resin (e.g., Pliolite S6B) can also be used to increase the hardness without increasing the viscosity significantly.
- High styrene resins are somewhat thermoplastic, and need to be fluxed into the rubber at temperatures of >95 °C.
- For applications not involving food contact or requiring FDA-compliance, high levels of the liquid methacrylates such as TMTPMA and DEGDMA can be used to increase hardness.
- Isocyanate cure systems (containing Thanecure® T9SF, HQEE and accelerator (e.g., Bismate) can also be used with Millathane 26 to achieve high hardness compounds with excellent strength properties, although thecure system components are also not compliant with FDA regulations.
- Resilience/Damping
Millathane millable urethanes can have resilience (rebound) values varying from below 10%, as seen with some Millathane 76 compounds, to over 60%, as seen with several polyether grades.
Low resilience compounds generally have excellent vibration damping characteristics and are used in instrument packaging and other vibration damping applications.
High resilience compounds tend to have lower heat build-up in dynamic applications such as rubber-covered rollers.
Generally, resilience will be higher with low filler loadings than with higher filler loadings. Peroxide cures will tend to give higher resilience than sulfur cures.
- Abrasion Resistance
- Abrasion resistance is the ability of a surface to resist wearing due to contact with another surface moving with respect to it.
- High resistance to abrasion is important in applications like rollers, belting, and helicopter dust covers.
- The DIN Abrasion Test (ASTM D5963) is one of the most common tests for measuring abrasion resistance.
- It's where a rotating cylindrical sample is passed across a rotating drum of abrasive and the amount of sample volume lost is measured.
- Typical abrasion resistance values for Millathane millable urethane compounds is 50-80 mm³.
- Some compounds can have abrasion resistance values as low as 25 mm³, depending on the polymer, cure system, and formulation.
- Polyurethane rubber provides the highest abrasion resistance of any rubber, synthetic or natural.
- Laboratory tests do not always predict the advantage of Millathane compounds over other rubbers, but field experience often shows a tremendous improvement in product lifetime when millable urethane replaces conventional rubber.
Packaging & Availability
- Packaging Information
Package size/carton: 38 pounds (17.2 kg).
Storage & Handling
- Shelf Life
- 3 years
- Storage Information
Stored under dry and cool conditions.