Priplast Polyester Oligomers

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Priplast Polyester Oligomers
Dimerized Fatty Acid Technology for Use in Epoxy
Toughening
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The BasisPripol Dimerized Fatty Acids

• Large hydrocarbon part (C36)
• hydrophobic
• hydrolytic resistance of derivatives
• affinity for non-polar matrices and surfaces

• Irregular non-crystalline structure
• flexibility
• low Tg
• flow, wetting

• Di-functional constituent for
• polyamides
• polyesters
• polyurethanes

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Use in Epoxy resins

• Dimer technology traditionally used in epoxy
  resins
• In polyamide curatives
• In modifed epoxies
• Why?
• Brings flexibility (vibration / stress
  absorption)
• Enhances hydrophobicity, weatherability and
  compatibility with organic matrices (tar,
  hydrocarbon resins)

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Modification of Rigid Polymers With Soft Segments
1.flexibilization
crystalline or high-Tg amorphous hard segments
low-Tg amorphous soft segments
soft domain, with glass transition temperature
close to that of the soft segment
hard domain, with melting point close to that of
the rigid homopolymer
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Modification of Rigid Polymers With Soft Segments
a bad try at flexibilization
hard and soft segments are small
copolymer too chopped up to form decent hard and
soft domains low melting point and strength,
high Tg, poor elastic recovery
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Modification of Rigid Polymers With Soft
Segments
2. impact modification
crystalline or high-Tg amorphous hard segments
low-Tg rubber balls
hard, rigid, high-melting matrix with cushions to
absorb impact stability of the compound is an
issue
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Dimer technology for epoxy modification
the low glass transition temperature of dimer
acid makes it suitable for flexibilization and
impact modification the low polarity and Tg of
dimer acid is a good strating point for phase
separation dimer acid itself is rather small as
a soft segment (MW 580) so optimal properties
cannot be reached
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Impact Modification Technology
Polyesters based on dimerized fatty acids allow
incorporation of larger mol wt soft segments,
potentially resulting in better toughening
performance etc.
n
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Advantages of Polyester Modification Technology

HOOC----
----- COOH
E-E
n

• Possibility to graft the soft segment on the
  epoxy
• Possibility to carefully control molecular weight
  and polarity
• To exactly establish the degree of phase
  separation required

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Additional Advantages

• Soft domains based on dimerized fatty acid are
  extremely hydrophobic, which reduces moisture
  diffusion through the matrix
• Polyesters based on dimerized fatty acids do not
  contain volatile toxic or smelly monomers
• Polyesters based on dimerized fatty acids are not
  susceptible to thermal or oxidative degradation
• Polyesters based on dimerized fatty acids have
  very low glass transition temperatures

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Existing Grafted Impact Modifiers

• CTBN-rubber (liquid rubber)
• a low-MW copolymer of acrylonitrile and butadiene
• contains unreacted double bonds
• High viscosity (60000 500000 mPa.s at 27 ºC)

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Test Epoxy Formulation

• Heat curable formulation
• 72 Pre-react
• dimer polyester low mol wt BPA epoxy (828
  type)
• 15 high mol wt BPA epoxy (1001 type)
• 4 Phenolic Novolac
• Catalyst
• Imidazole
• Cured at 175 C

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Effect of Polyester Polarity
Several acid-terminated polyesters of PRIPOL
1009, low-MW dioic acid and glycol
prepared Constant molecular weight Ratio of
PRIPOL 1009 to low-MW dioic acid varied HUGE
impact on reaction
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Modification with pure Pripol 1009 / glycol ester
(no short-chain dioic acid)
no grafting reaction components are too
incompatible polymer is brittle AND sticky
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Modification with ester of Pripol 1009 and short
dioic acid (75/25)
some grafting reaction components are still
incompatible polymer is brittle AND sticky
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Modification with ester of Pripol 1009 / short
dioic acid (50/50)
full grafting reaction good phase separation on
microscale polymer is hard AND tough
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Dimer technology for epoxy toughening, dimerate
vs CTBN
modifier property CTBN (1300X13) Dimerate (DA/SD/glycol)
glass transition temperature (ºC) 29 22
essential work of fracture (kJ/m2) 6.5 10.5
T-peel at ambient temperature (Ga) 60 66
T-peel at ambient after 40 h / 60 ºC / 60 RH (Ga) 57 87
Moisture Diffusivity (cm2/s) 3.0 x 10-4 0.8 x 10-4
Modifier viscosity (mPa.s) 500 000 15000 - 20000
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Conclusions

• Epoxy modification with dimerized fatty acid
  technology allows
• Flexibility or toughening (even at very low
  temperature)
• Good stability against heat, oxidation and
  moisture (as seen in other polymer systems)
• A toughener which is not too high viscosity
• Flexibility of chemistry allows tailoring of
  polyester molecular weight and polarity, to fit
  the base epoxy resin
• Allows desired morphology to be exactly achieved