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Suppliers merging with competitors?
FOCUS ON P O W D E R C O AT I N G S A MONTHLY REPORT FROM SID HARRIS
SUPPLIERS MERGING WITH COMPETITORS?
OCTOBER 2008 In this issue
TECHNICAL
2-4
Self healing powder coatings New polymers as high performance flow and levelling additives
INDUSTRY NEWS
4-7
Jotun shifting powder wing to Pune Bayer and AkzoNobel supply materials for Chinese Olympic stadium Enviro acquired by Protech New Turkish PPG customer New business moves in the UAE Uralac introduces first in HiTone PFA adhesive powder can be coated without primer Altana acquires effect pigment business of USBP Business digest: BASF Coatings starts up new plant
MARKETS Aerospace coatings
AN INTERNATIONAL NEWSLETTER MONITORING TECHNICAL AND COMMERCIAL DEVELOPMENTS IN POWDER COATINGS ISSN 1364–5439
7-8
Following the shock news that Dow Chemical had absorbed a major global coatings producer we are now faced with a major coatings producer taking over one of the prime suppliers with the news of BASF’s proposal to purchase Ciba. We are well accustomed to acquisitions and mergers with the industry, but this trend poses a new aspect to commercial developments in the future. Both Dow and Ciba are major producers of epoxy resins although their price structures have forced many powder producers to seek lower cost alternatives from Asian sources. Will these independent supplier companies become a target for the global growth of the aggressive coatings producer? It is certainly a new twist in the investment market that may not bode well for the medium to small coatings producers. Where will it end I wonder? It seems that in addition to the survival challenges already facing these companies, their burden might increase by the addition of another straw to the camel’s back. I confess that I find it difficult to relate the present state of the coatings industry to the friendly competitive years of my youth! There is, however, one current trend that does give me hope for the future. After the static years of the nineties, research and development has been given a
new lease of life. This would have been quite apparent to the formulators who were able to attend the recent Fatipec 2008 Congress. The scope and quality of most papers was excellent. There are two abstracted papers in this issue that substantiate my comments and there will be more in future issues to wet the appetites of formulators who could not attend this meeting. One paper that was directly applicable to powders coatings received plaudits from the organizers for its ingenuity and comprehensive detail. Marielle Wouters of TNO Science and Industry, located in The Netherlands, presented this paper, and it introduced a new concept in the use of thermally crosslinkable polymers as a reliable means of mending damaged powders coatings by simply heating the object above a certain threshold temperature, at which point the coating reflowed to completely wet the substrate and restore the original surface profile in a matter of seconds. When this is accomplished, cooling down the coated object restores the 3dimensional structure of the polymer. In this way the repair can be affected without any noticeable detriment to the performance of the coating. Trials carried out with both unpigmented and pigmented powder coatings gave acceptable levels of repair
POWDER COATINGS POWDER COATINGS POWDER COATINGS POWDER COATINGS
F O C U S although it was observed that the addition of pigment did have an effect on the melt viscosity of the coating. However, this well-known aspect of powder rheology was not as pronounced as the viscosity increase encountered in conventional pigmented powder coatings. The research programme also covered the effect upon coloured and metallic pigmented samples, which confirmed the remarkable mending qualities of the system on aluminium, steel and glass substrates. The work only covered a small number of reversible cross-linked copolymers but it did show that film qualities such as excellent gloss and levelling, good impact resistance, and good solvent resistance could be achieved. There is work still to be done to resolve flexibility and other desirable film properties, but it does point the way to producing self-sealing powder coating films. The second paper describes an alternative flow and levelling agent that overcomes many of the problems of existing commercial additives. Organically modified polysiloxanes are useful slip and levelling additives for they have low surface energies, high flexibility, low toxicity and good compatibility. Polyacrylates with perfluoroalkyl side chains also offer low surface energy, thermal stability and chemical resistance due to their hydrophobic character. The paper presented by Marcel van der Sluis of Ciba Heerenveen BV, in The Netherlands, introduces the potential for combinations of both fluorinated polymers and polysiloxanes in the same molecule. While the drawbacks to physical combinations of these polymers are incompatibility and recoatability it is claimed that combining fluorine and silicone moieties onto an acrylate backbone will provide the answer to these problems. Their use in polyester resins is shown to give excellent levelling qualities and
2
O N
POWDER
even at high addition levels, no intercoat adhesion problems were observed. They also offer the prospect of good bubble breaking characteristics. Sid Harris
TECHNICAL Self healing powder coatings The recent Fatipec 08 Congress introduced a wealth of new concepts in many areas of coatings technology. One presentation stood out amongst the others. Marielle Wouters of TNO Science and Industry, offered a novel method for the mending of powder coatings when she outlined the details of work carried out by a team of researchers at TNO in Holland. It is generally understood that the key physical properties of organic coatings are strongly influenced by the structure of the polymeric binder and a 3dimensional structure usually offers the best coating performance. Unfortunately, it is difficult to repair this structure when it becomes damaged. Molecular design combined with different synthetic modifications has resulted in a series of new building blocks that have the capability to make conventional types of coating thermally remendable, so that thermally reversible cross-linking through reversible bond scission within these special building blocks can repair damage. At room temperature the coating has a fully cross-linked network but at elevated temperatures the crosslink density becomes much lower allowing the system to be processable. The reversible crosslinking concept has been proved by various techniques and it has been shown that both the thermal reversibility window and the final coating properties can be tuned by careful design of the system.
C OAT I N G S The potential to thermally control covalent bond formation is a well-known characteristic that may be applied to both linear polymers and the formation of polymer networks. There are a number of chemical pathways to achieve the formation of thermally reversible covalent bonds but the most important procedure is via a Diels and Alder reaction since it requires very little energy to form a covalently connected ring structure. The most common choice is the reaction between furan and maleimide derivatives, which can produce a rubbery film at 100°C and then return to a remouldable polymer at 140°C. In this paper they describe the application of thermally reversible bond formation using the DielsAlder reaction in coatings. The benefits of 3-dimensional polymers in creating the key properties of mechanical strength, solvent resistance and permeability rely upon the structure of the polymeric binder, but 3dimensional networks also have disadvantages such as: the interference of the 3-D network formation causing immobilisation of the chains during the thermal cross-linking process, which restricts the optimal flow of the system, and this is a typical problem for powder coatings; there are also the problems of the brittle character of highly cross-linked systems after the curing process; and difficulties in the repair of possible damages. Systems containing thermally reversible cross-links can overcome these disadvantages. In the fully cross-linked state, below a certain threshold temperature, the coating will exhibit its essential properties, but above the threshold temperature, it will show some plasticity and flow. This plasticity will reduce problems during the film formation stage of powder coatings and will enable the repair of the coating using their self-healing properties. Using this concept, powder coatings can be applied in their fully cross-
OCTOBER 2008
SUPPLIERS MERGING WITH COMPETITORS?
OCTOBER 2008 In this issue
TECHNICAL
2-4
Self healing powder coatings New polymers as high performance flow and levelling additives
INDUSTRY NEWS
4-7
Jotun shifting powder wing to Pune Bayer and AkzoNobel supply materials for Chinese Olympic stadium Enviro acquired by Protech New Turkish PPG customer New business moves in the UAE Uralac introduces first in HiTone PFA adhesive powder can be coated without primer Altana acquires effect pigment business of USBP Business digest: BASF Coatings starts up new plant
MARKETS Aerospace coatings
AN INTERNATIONAL NEWSLETTER MONITORING TECHNICAL AND COMMERCIAL DEVELOPMENTS IN POWDER COATINGS ISSN 1364–5439
7-8
Following the shock news that Dow Chemical had absorbed a major global coatings producer we are now faced with a major coatings producer taking over one of the prime suppliers with the news of BASF’s proposal to purchase Ciba. We are well accustomed to acquisitions and mergers with the industry, but this trend poses a new aspect to commercial developments in the future. Both Dow and Ciba are major producers of epoxy resins although their price structures have forced many powder producers to seek lower cost alternatives from Asian sources. Will these independent supplier companies become a target for the global growth of the aggressive coatings producer? It is certainly a new twist in the investment market that may not bode well for the medium to small coatings producers. Where will it end I wonder? It seems that in addition to the survival challenges already facing these companies, their burden might increase by the addition of another straw to the camel’s back. I confess that I find it difficult to relate the present state of the coatings industry to the friendly competitive years of my youth! There is, however, one current trend that does give me hope for the future. After the static years of the nineties, research and development has been given a
new lease of life. This would have been quite apparent to the formulators who were able to attend the recent Fatipec 2008 Congress. The scope and quality of most papers was excellent. There are two abstracted papers in this issue that substantiate my comments and there will be more in future issues to wet the appetites of formulators who could not attend this meeting. One paper that was directly applicable to powders coatings received plaudits from the organizers for its ingenuity and comprehensive detail. Marielle Wouters of TNO Science and Industry, located in The Netherlands, presented this paper, and it introduced a new concept in the use of thermally crosslinkable polymers as a reliable means of mending damaged powders coatings by simply heating the object above a certain threshold temperature, at which point the coating reflowed to completely wet the substrate and restore the original surface profile in a matter of seconds. When this is accomplished, cooling down the coated object restores the 3dimensional structure of the polymer. In this way the repair can be affected without any noticeable detriment to the performance of the coating. Trials carried out with both unpigmented and pigmented powder coatings gave acceptable levels of repair
POWDER COATINGS POWDER COATINGS POWDER COATINGS POWDER COATINGS
F O C U S although it was observed that the addition of pigment did have an effect on the melt viscosity of the coating. However, this well-known aspect of powder rheology was not as pronounced as the viscosity increase encountered in conventional pigmented powder coatings. The research programme also covered the effect upon coloured and metallic pigmented samples, which confirmed the remarkable mending qualities of the system on aluminium, steel and glass substrates. The work only covered a small number of reversible cross-linked copolymers but it did show that film qualities such as excellent gloss and levelling, good impact resistance, and good solvent resistance could be achieved. There is work still to be done to resolve flexibility and other desirable film properties, but it does point the way to producing self-sealing powder coating films. The second paper describes an alternative flow and levelling agent that overcomes many of the problems of existing commercial additives. Organically modified polysiloxanes are useful slip and levelling additives for they have low surface energies, high flexibility, low toxicity and good compatibility. Polyacrylates with perfluoroalkyl side chains also offer low surface energy, thermal stability and chemical resistance due to their hydrophobic character. The paper presented by Marcel van der Sluis of Ciba Heerenveen BV, in The Netherlands, introduces the potential for combinations of both fluorinated polymers and polysiloxanes in the same molecule. While the drawbacks to physical combinations of these polymers are incompatibility and recoatability it is claimed that combining fluorine and silicone moieties onto an acrylate backbone will provide the answer to these problems. Their use in polyester resins is shown to give excellent levelling qualities and
2
O N
POWDER
even at high addition levels, no intercoat adhesion problems were observed. They also offer the prospect of good bubble breaking characteristics. Sid Harris
TECHNICAL Self healing powder coatings The recent Fatipec 08 Congress introduced a wealth of new concepts in many areas of coatings technology. One presentation stood out amongst the others. Marielle Wouters of TNO Science and Industry, offered a novel method for the mending of powder coatings when she outlined the details of work carried out by a team of researchers at TNO in Holland. It is generally understood that the key physical properties of organic coatings are strongly influenced by the structure of the polymeric binder and a 3dimensional structure usually offers the best coating performance. Unfortunately, it is difficult to repair this structure when it becomes damaged. Molecular design combined with different synthetic modifications has resulted in a series of new building blocks that have the capability to make conventional types of coating thermally remendable, so that thermally reversible cross-linking through reversible bond scission within these special building blocks can repair damage. At room temperature the coating has a fully cross-linked network but at elevated temperatures the crosslink density becomes much lower allowing the system to be processable. The reversible crosslinking concept has been proved by various techniques and it has been shown that both the thermal reversibility window and the final coating properties can be tuned by careful design of the system.
C OAT I N G S The potential to thermally control covalent bond formation is a well-known characteristic that may be applied to both linear polymers and the formation of polymer networks. There are a number of chemical pathways to achieve the formation of thermally reversible covalent bonds but the most important procedure is via a Diels and Alder reaction since it requires very little energy to form a covalently connected ring structure. The most common choice is the reaction between furan and maleimide derivatives, which can produce a rubbery film at 100°C and then return to a remouldable polymer at 140°C. In this paper they describe the application of thermally reversible bond formation using the DielsAlder reaction in coatings. The benefits of 3-dimensional polymers in creating the key properties of mechanical strength, solvent resistance and permeability rely upon the structure of the polymeric binder, but 3dimensional networks also have disadvantages such as: the interference of the 3-D network formation causing immobilisation of the chains during the thermal cross-linking process, which restricts the optimal flow of the system, and this is a typical problem for powder coatings; there are also the problems of the brittle character of highly cross-linked systems after the curing process; and difficulties in the repair of possible damages. Systems containing thermally reversible cross-links can overcome these disadvantages. In the fully cross-linked state, below a certain threshold temperature, the coating will exhibit its essential properties, but above the threshold temperature, it will show some plasticity and flow. This plasticity will reduce problems during the film formation stage of powder coatings and will enable the repair of the coating using their self-healing properties. Using this concept, powder coatings can be applied in their fully cross-
OCTOBER 2008