2014 processing techniques seminar plasticizers … processing techniques seminar plasticizers in...
Post on 08-May-2018
225 Views
Preview:
TRANSCRIPT
2014 Processing Techniques Seminar
Plasticizers in the
Polyurethane Industry
Presented by:
Mick Funderburg
Principal Technical Services Representative
Eastman Chemical Company
mfunderburg@eastman.com
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
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 (Tg)
Lowers the elastic modulus of the end product
3
How plasticizers work
Plasticizer theories
Lubricity theory
Gel theory / Mechanistic theory
Free volume theory
4
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
Internal plasticizers
Polyurethanes also considered examples
• Crystalline “hard” segments
Diisocyanates + low MW hydroxyl compounds
• Amorphous “soft” segments
Oligomers / diols
8
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
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
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
“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: Tg suppression, clarity of polymer system
Compatibility parameters
13
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 (Tg)
• Durometer hardness
• Viscosity of blend
14
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
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
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
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
What is a phthalate?
The term “phthalate” conventionally refers to
ortho-phthalates
• ortho-phthalate = phthalate
• meta-phthalate = isophthalate
• para-phthalate = terephthalate
DEHP
DEHI
DEHT
19
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
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 2015.
• 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.
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.
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
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
top related