New developments in anti-skinning and metal carboxylate technologies for oxidatively dried alkyd based coatings as an answer to the new legislative challenges

New developments in anti-skinning and metal carboxylate technologies for oxidatively dried alkyd based coatings as an answer to the new

legislative challenges.

Western Coatings SymposiumLas Vegas

Oct 25-28, 2015

Stefan Bankov

THE DEVELOPMENT OF NEW OXIME FREE ANTI-SKINNING TECHNOLOGY

TO WORK IN BOTH COBALT AND DRICAT® 2700F SERIES DRIED

COATINGS

Agenda• Oxime based anti-skinning agents

• Legislation

• Non-oxime previous developments

• Dura’s development of new oxime free anti-skinning agents

• Summary and conclusions


• Legislation




Anti-skinning Agents - Oximes• A range of oximes - available in the market place.• Mode of action – complexation through the oxime

group.• Applicability varies due to the differences in

evaporation rate.• MEKO (methyl ethyl ketoxime) - the most common

material used.


• Legislation




Legislation (I)• MEKO was included in the Community Rolling Action

Plan (CoRAP) in 2013• The tentative plan is to update the classification of

MEKO as:– Carc. 1B, H350– Acute Tox. 3, H301;– Acute Tox. 4, H312; Skin Sens. 1B, H317; STOT SE 3, H336– Eye Dam. 1, H318

• Date for intention: 2015-2016

Legislation (II)• Reclassification as Carcinogen 1B, H350, will imply a generic

restriction according to entry 28 of Annex XVII of the REACH Regulation which will affect sales to the general public of MEKO as a substance, as a constituent of other substances or in mixtures.

• The concentration of MEKO in coatings may exceed the generic concentration limits of ingredients of a mixture classified as carcinogen that trigger classification of the mixture according to the CLP Regulation.

• It is expected that a classification of MEKO as carcinogen 1B, H350, will lead to changes in consumer uses that may result in control of risks.


• Legislation




Non-oximes – Previous Developments

• Materials that have been extensively evaluated - Phenolics

- Amines- Quinones and hydroquinones

• Work by complexing the primary drier

Non-oximes - Pros and ConsPros• They are effective as

blocking / anti-skinning agents

• Wide range of possible variants

Cons• Non-evaporating - remain

in the coating• Retard drying time• Can have unpleasant

odour• Can increase yellowing• Difficult to work with –

low dosage rates


• Legislation




Dura’s New Developments

DriCAT® 216 and DriCAT® 232To be used with cobalt and DriCAT® 2700F series technology.

DriCAT® 2516 and DriCAT® 2532Combined directly with DriCAT® 2700F series technology to

maximise the performance into one easy to use product.

DriCAT® 216 and 232• They complex the primary driers: Co, Mn, Fe

• Starting point recommendations are calculated depending on:

- which and how much primary metal - which of the anti-skinning agents is used.

Working with Cobalt• Example: 1000kg of a coating at 50% resin solids using Cobalt at

0.05% metal on resin solids • % Resin solids x % Co metal on resin solids x batch size x 22.37 = Addition of

DriCAT® 232

• % Resin solids x % Co metal on resin solids x batch size x 19.66 = Addition of DriCAT® 216

• 50% x 0.05% x 1000 x 22.37 = 5.59kg DriCAT® 232• 50% x 0.05% x 1000 x 19.66 = 4.91kg DriCAT® 216

Important factors for the calculations

Evaluations• Commercially available paints without the driers and

anti-skinning agents.

• Anti-skinning tests carried out in open and closed can – 2/3 full.

• All tests compared to the current standard drier and anti-skin combination used for the paint in use.

• Drying tests run on drying recorder.

Example

Working with Manganese*• Example: 1000kg of a coating at 50% resin solids using Manganese at 0.05% metal on

resin solids

• % Resin solids x % Mn metal on resin solids x batch size x 18.00 = Addition of DriCAT® 232

• % Resin solids x % Mn metal on resin solids x batch size x 15.82 = Addition of DriCAT® 216

50% x 0.05% x 1000 x 18.00 = 4.50kg DriCAT® 23250% x 0.05% x 1000 x 15.82 = 3.95kg DriCAT® 216

* For use with highly active manganese complexes we recommend DriCAT® 2532 and 2516

Important factors for the calculations

DriCAT® 2516 and DriCAT® 2532

• Why DriCAT® 2516 and DriCAT® 2532?– Ratio metal / amount of the new anti-skins is very

important– Addition rates of the new anti-skins in a production

environment could lead to errors of loading when working with Dura’s DriCAT® 2700F series products.

Incorporation of the new anti-skinning agents into Dura’s very high activity DriCAT® 2700F series technology

DriCAT® 2516 and 2532 - Advantages• Eliminate the requirement for:

– Cobalt carboxylates– Oxime based anti-skinning agents.

• Do not impart a green coloration to the wet coating.

• Superior initial and long term color performance, especially in the reduction of dark yellowing of whites.

Cobalt Carcinogenicity• Currently, there is no grouping paradigm for cancer.

• In the absence of any data or indication that two groups of cobalt substances exist (group 1 – Carc 1B, group 2 – NOT Carcinogenic), it is possible that an approach will be to assume carcinogenicity for any substance containing cobalt.

• The CoRC are attempting to show that there are a group of “biologically inert” cobalt compounds.

Initial Guidance• Anti-skinning agent is removed from the

formulation.

• Cobalt is replaced by DriCAT® 2516 or 2532 by following the guidance provided.

• Adjustments to the co-driers are made to maximise the performance.

Example

Maximising Performance• Achieving maximum performance is about

finding the correct balance of DriCAT® 2516 or 2532 with the co-driers.

BALANCE IS THE KEY


• Legislation




Summary and Conclusions• DriCAT® 216 and DriCAT® 232 - developed as oxime free

anti-skinning agents to work with any primary drier.

• DriCAT® 2516 and DriCAT® 2532 - developed as combined all-in-one cobalt and oxime free technology.

• Guidance available to provide starting point recommendations.

Thank you

Any Questions?

Documents

New developments in anti-skinning and metal carboxylate technologies for oxidatively dried alkyd based coatings as an answer to the new legislative challenges