New Keltan Grades for Flame Resistant EPDM Compounds Speaker: Philip Hough, Keltan M&S, TSAD

Transcription

1 New Keltan Grades for Flame Resistant EPDM Compounds Speaker: Philip Hough, Keltan M&S, TSAD SGF Conference, Malmö 10 th 11 th April 2013

2 Contents Introduction 1.1 The move towards metal hydrates 1.2 The mechanism of metal hydrate flame retarders 1.3 Compounding with metal hydrates 2. EPDM Compounds 2.1 Keltan 1519R for improved physical properties 2.2 Keltan 0500R for improved processing 3. Conclusions

3 1. Introduction The Kings Cross St Pancras fire of 1987 killed 31 people and injured another 60. Many of the deaths and injuries were caused by thick acrid smoke from halogen containing polymers. This tragedy led to London Underground introducing Fire Precautions Regulations (Section 12 Regulations) in This aimed to minimize the risks associated with the generation of noxious, corrosive fumes, and dense smoke from halogen containing products, including PVC cable insulation, and led to a general trend towards the use of Zero Halogen Products in enclosed public places. This move towards non-halogen containing polymers created an opportunity for EPDM However: EPDM Burns!

4 1.1 Introduction The move towards metal hydrates For applications requiring flame resistance it is therefore necessary to develop compounds containing ingredients that; Give non-burning properties and/or Raise the temperature of ignition and/or Give self extinguishing properties Give fumes of low toxicity Reduce the spread of flames Have a low smoke density

5 1.1 Introduction The move towards metal hydrates Many traditional flame retardants are therefore excluded, e.g. Material Brominated diphenyl esters/ethers Antimony oxide Halogenated phosphorous products Halogenated paraffins Red phosphor Objection Release of toxic and corrosive gas Contains heavy metal toxic Release of toxic and corrosive gas Release of toxic and corrosive gas Phosphine formation in contact with water Therefore the use of metal hydrates becomes a logical option

6 Contents Introduction 1.1 The move towards metal hydrates 1.2 The mechanism of metal hydrate flame retarders 1.3 Compounding with metal hydrates 2. EPDM Compounds 2.1 Keltan 1519R for improved physical properties 2.2 Keltan 0500R for improved processing 3. Conclusions

7 .2 Metal Hydrate Mechanism of Flame Retardation Use of metal hydrates Aluminium trihydrate (ATH): > 200 C 2 Al(OH) 3 Al 2 O H 2 O 1051 J/g > 340 C Magnesium dihydrate: Mg(OH) 2 MgO + H 2 O 1316 J/g Data Source: ALBERMARLE

8 .2 Metal Hydrate Mechanism of Flame Retardation Endothermic reaction from water emission Dilution of flammable gases due to formation of water vapour Moisture shroud reduces oxygen availability Formation of protective char leading to; Thermal insulation Adsorption of smoke particles Reference: EFRA Reduced % of polymer in compound Data Source: ALBERMARLE

9 Contents Introduction 1.1 The move towards metal hydrates 1.2 The mechanism of metal hydrate flame retarders 1.3 Compounding with metal hydrates 2. EPDM Compounds 2.1 Keltan 1519R for improved physical properties 2.2 Keltan 0500R for improved processing 3. Conclusions

10 1.3 Compounding of EPDM with Metal Hydrates Relative Effect on LOI Relative Effect of Filler and Plasticizer on Limiting Oxygen Index (LOI) Value of an EPDM Compound ATH Mg(OH)2 Clay Whiting Par. Oil Ester Oil Ingredient Zinc Borate also considered to give a synergistic improvement in combination with ATH and Mg(OH)2 Calcium carbonate, silica, silicates and sulphates also give some flame retardant benefit, probably due to dilution of combustible material, i.e. the polymer

11 1.3 Compounding of EPDM with Metal Hydrates General Rules To achieve a reasonable level of flame resistance (LOI > 30) AT LEAST 50 wt% of the compound should be metal hydrate Zinc borate has been found to give synergistic improvements when used in combination with hydrated fillers Paraffinic processing oil reduces LOI, and should only be used <15phr Phosphate and ester plasticizers have less effect on LOI, but have limited compatibility with EPDM; use at levels of < 15phr

12 1.3 Compounding of EPDM with Metal Hydrates Disadvantages of using metal hydrates for flame resistant EPDM Metal hydrates act as diluent fillers, having no reinforcing properties. High loadings cause a reduction of physical properties High filling levels coupled with low oil addition result in high viscosity compounds that are difficult to process Keltan Solutions Keltan 1519R Keltan 0500R MAH grafted EPM for polymer / filler coupling Very low viscosity EPM for improved processing

13 Contents Introduction 1.1 The move towards metal hydrates 1.2 The mechanism of metal hydrate flame retarders 1.3 Compounding with metal hydrates 2. EPDM Compounds 2.1 Keltan 1519R for improved physical properties 2.2 Keltan 0500R for improved processing 3. Conclusions

14 2.EPDM Compounds 2.1 Keltan 1519R For Improved Physical Properties Product Description Low molecular weight amorphous copolymer grafted with 1.9 wt% maleic anhydride produced by reactive extrusion technology Property Unit Typical Value Test Method Polymer type Copolymer Ethylene content Wt% 49 ASTM D 3900 Grafted Maleic Anhydride Wt% 1.9 FT-IR Molecular weight distribution Narrow GPC Mooney Viscosity ML(1+4) 125 C MU 65 ISO 289 Melt flow Index 190 C/2.16kg g/10 min 4.5 ASTM D1238

15 2.1 Keltan 1519R For Improved Physical Properties High ATH Filled Compound Keltan phr Keltan phr Mooney ML 100 C ISO 289 KELTAN KELTAN Keltan 1519R 10 Carbon black N Whiting ATH Paraffinic oil DOA ZnO 5 5 Stearic acid 1 1 TEA 1 1 Rhenogran CaO Rhenogran CBS Rhenogran TMTD Rhenogran ZDBC Rhenogran S Total phr Keltan phr Keltan phr Initial [MU] ML [MU] Increased Mooney due to; MA cluster formation Improved polymer / filler interaction

16 2.1 Keltan 1519R For Improved Physical Properties Improved Tensile Properties 0phr Keltan 1519R / 200phr ATH 10phr Keltan 1519R / 200phr ATH 16

17 2.1 Keltan 1519R For Improved Physical Properties Improved Tensile Properties The addition of Keltan 1519R gives: Dramatic increase of stress load at low strain levels Higher ultimate tensile strength No loss of final elongation 17

18 2.1 Comparison of Tensile Strength for ATH, Mg(OH) 2 and Clay in Peroxide Cured W&C Compound Fillers used at 150phr Tensile strength/keltan 1519R content Martinal OL-107C ATH Surface modified aluminum hydroxide Clay Burgess Surface modified calcined aluminum silicate Magnifin H10A Magnesium hydroxide vinyl silane coated Total compound = 361phr Tensile strength improves for ATH and Mg(OH)2, but not effective for Clay Tensile strength (M Pa) Keltan 1519R (Phr) ATH Clay MgOH 18

19 Contents Introduction 1.1 The move towards metal hydrates 1.2 The mechanism of metal hydrate flame retarders 1.3 Compounding with metal hydrates 2. EPDM Compounds 2.1 Keltan 1519R for improved physical properties 2.2 Keltan 0500R for improved processing 3. Conclusions 19

20 2.2 Keltan 0500R for Better Processing Polymer Properties Product Description Amorphous ethylene/propylene copolymer with very low Mooney viscosity produced via a down shearing process. This grade can be used as a polymeric plasticizer in low-oil or oil-free EPDM based compounds to give improved processability Property Unit Nominal Value Test Method Ethylene Content wt% ASTM D3900 Melt Flow Index 2.16kg / 190 C g / 10 min ASTM D1238 Volatile Matter wt% < 0.5 ISO 248/ASTM D

21 2.2 Keltan 0500R for Better Processing Handles Like Rubber Unlike other plasticizers, bales can be unpacked, cut, mixed and conveyed like regular Rubber bales Managing the cold flow: Exhibits cold flow behavior Packaging consists of individual, non-leaking, easy release boxes Upright storage of boxes is required Remainder of bales can easily be stored in original boxes 0 hours 24 hours

22 2.2 Keltan 0500R for Better Processing Low Oil Belt Compound Finding the balance between processing and compound performance for oil free applications Successively replace K6160D by ultra low viscosity K0500R as polymeric plasticizer The low molecular weight polymer facilitates processing under shear conditions The high molecular weight polymer helps to maintain mechanical properties K6160D/K0500R 100/0 90/10 80/20 70/30 60/40 50/50 Keltan 6160D Keltan 0500R CB N Paraffinic Oil Paraffin Wax Zinc Oxide tackifying Resin Zinc Stearate Perkadox Coagent Total phr

23 2.2 Keltan 0500R for Better Processing Broadening of Molecular Weight Distribution K740 K6160D K1200A K0500R 50/50 blend log MW

24 2.2 Keltan 0500R for Better Processing Conclusion: Strongly reduced ML while maintaining similar physical properties K6160D K740 K740 pure 90/10phr 80/20phr 70/30phr 60/40phr 50/50phr T.S. T.S. [MPa] [MPa] Hardness [ Sh.A] Tear str. Delft [N] Elongation [%] ML

25 2.2 Keltan 0500R for Better Processing Conclusion: Strongly reduced ML with only a small loss of elasticity (may be compensated by small peroxide increase) K6160D pure K740 10phr 20phr 30phr 40phr 50phr Comp. Set 23 C [%] Comp. Set 100 C [%] Comp. Set 150 C [%] ML 0

26 2.2 Keltan 0500R for Better Processing Application Recipe; HFFR Cable Compound 100/0 85/15 K2470L K0500R 15 N DIDP ZnO 5 5 Stearic acid 1 1 Cao ATH (Martinal OL-107C) Perkadox MB 5 5 TAC Total phr Burn Testing UL-94 Vertical test 100/0 85/15 Rating V2 V2 Note; No drip/deposit of test pieces was observed Test Results 100/0 85/15 1) Rheological properties 100 C [MU] MDR at 180 C T2 [min] T90 [min] MH-ML [dnm] Garvey Die rating 3/3/3/3 3/4/4/4 Vulcanised properties Cure 12min. 180 C 100% Mod. [MPa] T.S. [MPa] E.B. [%] Hardness [ShA] Comp.set [%] 22hr.70 C

27 Contents Introduction 1.1 The move towards metal hydrates 1.2 The mechanism of metal hydrate flame retarders 1.3 Compounding with metal hydrates 2. EPDM Compounds 2.1 Keltan 1519R for improved physical properties 2.2 Keltan 0500R for improved processing 3. Conclusions

28 3. Conclusions A general trend towards the use of zero halogen products in enclosed public places has necessitated the use of non-halogen containing polymers in combination with metal hydrate fillers. To be effective as flame retarders, metal hydrate fillers must be used at levels of at least 50 wt% in compounds containing low levels of processing oil. This adversely effects both the processing and cured physical properties of the compound. Lanxess Keltan Elastomers offers innovative products that improve both processing and physical properties of high filled, low oil EP(D)M based compounds; Keltan 1519R gives coupling between metal hydrate fillers and EP(D)M polymer to improve physical properties Keltan 0500R reduces compound viscosity for improved process flow, with a minimum effect on physical properties

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