2014 Processing Techniques Seminar Plasticizers in the Polyurethane Industry

Transcription

1 2014 Processing Techniques Seminar Plasticizers in the Polyurethane Industry Presented by: Mick Funderburg Principal Technical Services Representative Eastman Chemical Company

2 Topics to cover What plasticizers are and traditional uses of plasticizers How and why plasticizers are used in polyurethanes Benefits and limitations of plasticizer use What phthalates are and why they matter to you Regulatory issues and timeline with plasticizers What to look for in a plasticizer supplier 2

3 What is a plasticizer? Plasticizer a substance or material incorporated in a material (usually a plastic or elastomer) to increase its flexibility or workability Will likely affect the viscosity of the formulation Lowers the temperature of a second-order transition Such as the glass transition temperature (T g ) Lowers the elastic modulus of the end product 3

4 How plasticizers work Plasticizer theories Lubricity theory Gel theory / Mechanistic theory Free volume theory 4

5 Traditional uses for plasticizers Flexible PVC 5

6 Traditional uses for plasticizers Adhesives and sealants 6

7 Internal plasticizers Flexible segments incorporated into the polymer chain Adds flexibility and toughness Examples: Polyvinylacetate + ethylene = vinyl acetate ethylene (VAE) ABS (acrylonitrile butadiene styrene) Block copolymers (SIS, SEBS, etc.) Components of ABS polymer chain 7

8 Internal plasticizers Polyurethanes also considered examples Crystalline hard segments Diisocyanates + low MW hydroxyl compounds Amorphous soft segments Oligomers / diols 8

9 External plasticizers in polyurethane systems Why use an external plasticizer? Regulate rheology Lower viscosity of reaction medium Reduce polymer viscosity Regulate thermal properties Regulate mechanical properties Improve softness/increase flexibility 9

10 Plasticizer use in Polyurethane systems Benefits Viscosity reduction - easier compounding Cost reduction plasticizers cost less than base polymer and allow for higher filler loading Reduced glass transition temperature lower tensile strength, hardness and increased elongation 10

11 Plasticizer use in Polyurethane systems Limitations Concentration limited to less than 30% by weight Compatibility must be tested with specific formulations no one size fits all plasticizer Migration issues lead to decreased performance over time Some monomeric plasticizers do not hold up under extreme conditions and polymeric plasticizers are expensive 11

12 Plasticizer selection parameters Compatibility Efficiency Permanence Processability Regulations 12

13 Compatibility parameters Like solvates like Capable of forming a homogenous mixture Plasticizer does not react chemically with other system components Polarity Hydrophilic / lipophilic balance How to determine Theoretical: Calculate solubility parameter Experimental: T g suppression, clarity of polymer system 13

14 Efficiency parameters Efficiency: tool to compare plasticizers The amount of plasticizer needed to obtain a specific value for a specific performance property Some comparative tests for polyurethane elastomers Tensile properties Elongation properties Resiliometer Glass transition temperature (T g ) Durometer hardness Viscosity of blend 14

15 Permanence parameters Permanence: a measure of how long the plasticizer will stay in the polymer matrix and function as intended Factors affecting permanence of a plasticizer Molecular weight Compatibility Environment Tests to determine permanence Volatility (neat plasticizer or in polymer matrix) Extraction resistance Migration resistance 15

16 Processability parameters Plasticizer compatibility with the polymer affects the workability of the system during processing So, plasticizers can affect Viscosity Melt viscosity Processing temperature Moldability Calenderability Vacuum forming characteristics 16

17 Additives for better mold definition Standard formulation (based upon TDI-terminated polyester prepolymer / aromatic diamine system) Same formulation with addition of 5% Eastman TXIB formulation additive 17

18 Classes of plasticizers Adipates Azelates Benzoates Citrates Epoxidized oils Ethers Fatty acid esters Glycerol esters Glycols and glycol esters Hydrocarbons Paraffins (halogenated) Pentaerytheritol esters Phosphates Phthalates Polyesters Soy and other oil derivatives Stearates Sulphonamides Sulfonates Terephthalates Terpenes and derivative Trimellitates 18

19 What is a phthalate? The term phthalate conventionally refers to ortho-phthalates ortho-phthalate = phthalate DEHP meta-phthalate = isophthalate DEHI para-phthalate = terephthalate DEHT 19

20 Why phthalates matter Migration out of polymer leads to environmental questions Metabolism of phthalates creates a stable monoester, which is blamed in some toxicology studies Risk assessments disagree about the extent of the risk surrounding phthalates Increasing regulatory attention being given by many agencies to ortho-phthalates 20

21 Regulatory Shift to Non-Phthalates (ECHA) European REACh regulation Four targeted ortho-phthalates (DEHP, DBP, DIBP, BBP) in Europe s official process to ban substances in commerce except for authorized uses. Very few authorized uses for phthalates are expected. All non-authorized uses will be banned effective Feb Except for authorized uses, no products containing the four listed phthalates will be allowed to be manufactured or imported in EU after this date. ECHA ban on DINP and DIDP in toys Late-August 2013 ECHA confirmed that the ban on use of DINP and DIDP in toys and childcare articles is permanent. 1 They performed an open review of the ban from 2008 and accepted comments and reviewed the latest data and studies. Ultimately they stated that adverse effects from exposure to young children by mouthing items containing DINP and DIDP could not be ruled out, so the ban was confirmed.

22 Regulatory Shift to Non-Phthalates (U.S.) US Environmental Protection Agency s Chemical Action Plan Includes IRIS reassessments of phthalates, adding the phthalates to the Chemicals of Concern list, and a Design for the Environment (DfE) alternatives assessment that includes 96 possible alternatives. Alternatives assessments on: DEHP, DBP, BBP, DIBP, DIDP, DINP, DnOP, DnPP US Consumer Product Safety Commission (CHAP) Under the 2008 CPSIA law, DEHP, DBP, and BBP were permanently banned for toys and childcare articles. DINP, DIDP, and DnOP were temporarily banned for use in toys and childcare articles, subject to further review. The CHAP is performing that review and an alternatives assessment for all six of the phthalates.

23 What to look for in a plasticizer supplier Reliable source of supply Technical formulation and analytical support Varied product line to fill any need Knowledge of regulatory issues and changes 23

24 Session summary What plasticizers are and traditional uses of plasticizers How and why plasticizers are used in polyurethanes Benefits and limitations of plasticizer use What phthalates are and why they matter to you Regulatory issues and timeline with plasticizers What to look for in a plasticizer supplier 24

25 Thank you!