Formulate extremely durable Polyurethane Coatings
Formulating the right
Polyurethane coatings that can resist to extreme environmental conditions while ensuring durable high performance is a challenge.
Polycarbonate Diols (PCD) and Polycarbonate-based Polyurethane Prepolymers offer customizable possibilities with superior and long-term retention of designed performances, without modification of initial properties after being exposed in harsh environments.
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The outstanding durability of Polyurethane coatings based on PCD or Polycarbonate-based Polyurethane Prepolymers is obtained thanks to different performances, such as:
Access more information about the best-in-class performances of Polycarbonate Diol-based Polyurethane coatings, click on the pictures:
Excellent water resistance of Polyurethane Coatings
Polycarbonate Diols (PCD) and Polycarbonate-based Polyurethane Prepolymers provide increased water and hydrolysis resistance to Polyurethane Coatings.
Figure 1 shows that water absorption is less important (-52%) for Polyurethane Coatings based on Polycarbonate Diols and Polycarbonate-based Polyurethane Prepolymers.
This leads to minor weight increment and better resistance to hydrolysis than PU based on benchmark Diols.
Figure 1: Water absorption of Diol-based Polyurethane Coatings
Therefore, PU coatings formulated with Eternacoll® polycarbonate diols or Eternathane® polycarbonate-based polyurethane prepolymers withstand extreme humid conditions. They remain intact after long-term exposure to water and humidity.
Increased chemical & stain resistance of Polyurethane Coatings
Exposure to harsh solvents and fluids tends to damage Polyurethane coatings over time, causing them to fade, discolor and get stained.
Polycarbonate Diols and Polycarbonate-based Polyurethane Prepolymers can help you to overcome this annoying constraint. They enhance the chemical and stain resistance of your PU formulations.
Chemical resistance
An ethanol resistance test was run in order to compare the chemical resistance of Diol-based Polyurethanes (see picture 1).
As illustrated on Figure 2, PU formulated with Eternacoll® PCD shows an improved resistance to harsh solvents compared to PU based on benchmark Diols. Results were similar with Polycarbonate-based Polyurethane Prepolymers.
Picture 1: Ethanol resistance test of
PCD-based Polyurethane Coatings
ISO 2812-1:2007 - Paints and varnishes
Determination of resistance to liquids
Part 1: Immersion in liquids other than water
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Figure 2: Ethanol resistance of Diol-based PU
*5 = Intact coating after exposure
4 = Slight change in gloss or color
3 = Light mark
2 = Strong mark
1 = Coating removal
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The use of Eternacoll® Polycarbonate Diols or Eternathane® Polycarbonate-based Polyurethane Prepolymer in your PU formulations allows you to provide highly durable Polyurethane coatings that can better resist to exposure of chemicals.
This makes Eternacoll® PCD and Eternathane® Polycarbonate-based Polyurethane Prepolymer suitable for applications in which Polyurethane coatings have to resist to very harsh environmental conditions, such as oil & mining pipes coatings.
Stain resistance
Last but not least, Polycarbonate Diols and Polycarbonate-based Polyurethane Prepolymers also give an outstanding stain resistance to Polyurethane coating, as illustrated on the pictures below:
Eternacoll® UH100
based PUD
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PPG-based PUD
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| Picture 2: Stain resistance of Diol-based Polyurethane Coatings |
Higher thermal stability of Polyurethane coatings
Is temperature resistance a must-have for your Polyurethane coatings? If you can't afford to provide PU that tends to yellowish over time, then PCD is the technology you have always been looking for!
Polycarbonate Diols and Polycarbonate-based Polyurethane Prepolymers provide a very high thermal stability to Polyurethane Coatings compared to traditional Polyester and Polyether Diols, thanks to excellent heat resistance.
Figure 3 illustrates that Eternacoll® PCD has a very low increment of yellowness index after artificial weathering compared to standard Polyether and Polyester Diols.
Results were similar with Eternathane® Polycarbonate-based Polyurethane Prepolymers.
Figure 3: Increment of yellowness index of Diols-based PU
ISO 3248:1998 - Measurements after 15 days at 120° C
Figure 4 and Picture 3 illustrate the excellent retention of initial PU properties of Eternacoll® PCD based PU after heat ageing, for an improved durability of your coatings! Results were similar with Eternathane® Polycarbonate-based Polyurethane Prepolymers.
Figure 4: Retention* of hardness Persoz
ISO 1522:2007 - Paints and varnishes - Pendulum damping test
*Retention = (property after ageing)/(initial property) x 100
Eternacoll® UH100
based PUD
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PPG-based PUD
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Polyadipate of 1,6-hexanediol
based PUD
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Picture 3: Pictures of Diol-based Polyurethane Coatings after heat exposition |
Therefore, Eternacoll® Polycarbonate Diols and Eternathane® Polycarbonate-based Polyurethane Prepolymers allow to provide highly durable Polyurethane Coatings that resist to heat and can be used for applications exposed to high temperatures.
Improved mechanical properties of Polyurethane Coatings
Formulating with Polycarbonate Diols (PCD) or Polycarbonate-based Polyurethane Prepolymers enables to maximize the mechanical properties of Polyurethane Coatings Formulation. How?
PU based on Eternacoll® PCD and Eternathane® Polycarbonate-based Polyrethane Prepolymers shows better mechanical properties compared to PU based on traditional Diols:
- The PU coating has a better tensile strength (+329%) and is therefore less elastic (Figure 5)
- It also shows a better hardness (+173%), as illustrated on Figure 6
Figure 5: Tensile strength of Diol-based PU |
Figure 6: Hardness of Diol-based PU |
The improvement of mechanical properties yields to less elastic and harder Polyurethane, for a highly durable coating!
Better gloss retention of Polyurethane coatings based on Polycarbonate Diols
Polycarbonate Diols and Polycarbonate-based Polyurethane Prepolymers provide a superior and long-term retention of coating gloss, without modification of initial properties after being exposed to harsh environments.
The graphs below illustrate the excellent retention of initial Polyurethane coatings' gloss thanks to ETERNACOLL® Polycarbonate Diols. ETERNATHANE® Polycarbonate-based Polyurethane Prepolymer showed the same performance. They are compared to standard Diols, after ageing at different heat conditions:
Figure 7: Retention of gloss 60° for Diols-based PU
ISO 3248:1998 - Measurements after 15 days at 120° C
*Retention = (property after ageing)/(initial property) x 100
Eternacoll® Polycarbonate Diols and Eternathane® Polycarbonate-based Polyurethane Prepolymer show a better retention of gloss and thus improve the overall durability formulation compared to standard Polyester and Polyether Diols!
Increased scratch & abrasion resistance of Polyurethane coatings
Polyurethane coatings formulated with Polycarbonate Diols and Polycarbonate-based Prepolymers show increased abrasion and scratch resistance, and are therefore more durable than Polyurethane coatings formulated with standard Diols.
Abrasion resistance
Figure 8 shows that PU based on Eternacoll® Polycarbonate Diols loses less volume when exposed to harsh conditions than PU based on traditional Diols. Results were similar with Eternathane® Polycarbonate-based Prepolymers. Therefore, it brings a better resistance to abrasion:
Figure 8: Abrasion resistance (Volume Loss of Coating) of
Diol-based PU when exposed to harsh conditions
Scratch resistance
Scratch resistance of PCD-based PU has been tested thanks to the determination of film hardness with pencil test.
Figure 9 illustrates that Eternacoll® PCD-based Polyurethane coatings have a higher hardness and therefore an increased scratch resistance than benchmark Diols. Results were similar with Eternathane® Polycarbonate-based Prepolymers.
Figure 9: Conditions of Pencil test - Determination of film hardness
ISO 15184:1998 - Paints and varnishes
The use of Polycarbonate Diols and Polycarbonate-based Prepolymers such as Eternacoll® and Eternathane® in PU formulations allows to develop extremely durable PU coatings that can resist to intense environmental conditions.