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New powder technologies and market opportunities
FOCUS ON P O W D E R C O AT I N G S A MONTHLY REPORT FROM SID HARRIS
NEW POWDER TECHNOLOGIES AND MARKET OPPORTUNITIES
JULY 2009 In this issue
TECHNICAL
2-3
Low temperature cure thermosetting polyamide resins
INDUSTRY NEWS
3-6
AkzoNobel 1Q 2009: Performance Coatings: industrial activities Kemira: Tikkurila has acquired rest of shares in its industrial coatings companies in Russia Ferro reports 1Q 2009 results: performance coatings Biotechnology and fermentation could be the way forward for coatings materials Trimite merges with Weilburger Coatings Jotun targets 8% market share
MARKETS
AN INTERNATIONAL NEWSLETTER MONITORING TECHNICAL AND COMMERCIAL DEVELOPMENTS IN POWDER COATINGS ISSN 1364–5439
6-8
The global market for high heat resistant coatings Not-so-little Italy: coatings market Coatings will ride out auto decline German powder market holds firm
Occasionally, a new aspect of thermosetting powder coatings technology is revealed with the potential to provide an additional inroad into new and profitable market opportunities. The latest development by DSM Resins of low temperature cure thermosetting polyamide resins is a significant advance in powder coatings technology and the abstracted account is, therefore, a more detailed assessment of its future role in the powder coatings industry. In the early years of thermosetting powder coatings, before the existing extruders were adapted to handle the lower viscosities and higher reactivities of thermosets, the thermoplastic polyamides or Nylon polymers were extruded at high torques and high temperatures and cut into small granules. They were unsuitable for use in powder coatings, despite the attractive features of high wear and chemical resistance, because of their high melting points, poor adhesion to metallic substrates, and difficulties in grinding these materials. Attempts to modify these materials as toughening additives in thermosetting powder formulations were unsuccessful. Now they have been re-invented by DSM Resins and I am sure that all formulators of thermosetting powders will be interested in this new binder species.
Market opportunities that have been explored by powder producers in the wide variety of high heat resistant coatings have only been partially successful. Although the demand for these coatings is increasing at almost 6% annually, the share of powder coatings is only a mere 14% of the total market and they are missing out to liquid coatings for reasons, which I find difficult to accept. It is claimed that the higher film thicknesses of powder coatings are not able to withstand the thermal stresses of high temperature service conditions when compared to the performance of thinner liquid coatings. While powder coatings are certainly more capable of applying much thicker films in one-pass applications than liquid coatings, recent advances in control of particle size distribution and lower average particle sizes, have made thin films a reality. With the advent of radiation curable powder systems possessing lower melt viscosities and enhanced film flow, there is no valid reason why formulators cannot improve their high heat resistant powders to meet the challenge of liquid coatings. In the areas of flame retardancy coatings the ability of powders to apply higher thickness one-pass films should be beneficial. Perhaps it is time to upgrade our heat resistant powder coatings to
POWDER COATINGS POWDER COATINGS POWDER COATINGS POWDER COATINGS
F O C U S include the latest technical advances! The review of latest developments in the production of nanocomposite films is included because it illustrates the use of well-established coatings technologies in the preparation of these films. We can all learn from the experiences of other industries! Sid Harris
TECHNICAL Low temperature cure thermosetting polyamide resins The application of low temperature powder coatings to heat sensitive substrates such as wood and plastics is still only a small segment of the total powder coatings market accounting for 0.1% according to DSM Resins, and powder coatings represent only 2% of coatings applied to MDF. However, the growth potential for powder coatings in this market segment has prompted DSM to develop new low temperature cure thermosetting polyamides, which is a completely new concept in powder coating binders. Thermoplastic polyamides have the unique properties of high toughness, high impact resistance and a low friction coefficient. The high wear resistance of polyamides is due to the strong hydrogen bonds between the amide groups, and this is also reflected in their good chemical resistant qualities. Thermoplastic polyamides such as Nylon-11 and Nylon-12 have not been widely used in powder coatings because of their poor adhesion to metal surfaces. They have crystalline structures and are characterized by high melting points and high molecular weights. They are also difficult to process and apply, and they possess high sensitivity to impurities. DSM has now developed amorphous polyamides 2
O N
POWDER
for use in thermosetting powder coating applications. The synthesis of these amorphous polyamides is relatively fast and uncomplicated. The DSM products are based on the combination of dibasic, mainly aliphatic, acids with diamines at temperatures below 100°C, followed by condensation and continuous removal of water of reaction at temperatures above 160°C. It is possible to control resin properties such as glass transition temperatures (Tg), functionality and viscosity due to the wide variety of raw materials available. Tg’s can be varied from –40 to 200°C with a wide range of functionalities. The ratio of the reacting monomers dictates the type of functionality, which can be either acid or amine. The amorphous nature of the polymer is assured by the choice of components that partially modify the regular structure of the polymer by the introduction of non-symmetrical monomers, such as isophorone diamines or other non-linear diamines. Experimental details are described in the recent paper presented at the European Coatings Congress. A list of twelve commercially available monomers offers a wide choice of basic raw materials. In the laboratory preparation water amine and additives are charged to the reactor and the acids are slowly added. The mixture is then heated to 220°C with removal of water and maintained at this temperature for at least 1 hour. The resin is then vacuum distilled for at least thirty minutes Special additives are incorporated and stirred in for a further thirty minutes, when the resin is discharged, and cooled. The powder coatings are then formulated according to their functionality. Acid functional polyamide resins can be cured with epoxies, TGIC or derivatives and ß-hydroxyalkylamides, while the amine functional resins, which are even more reactive than hydroxylated polyester resins, can be crosslinked by blocked
C OAT I N G S isocyanates and epoxies. The powder coatings are prepared by conventional methods using a twin-screw extruder at zone settings of 80 to 120°C and speeds in excess of 200 rpm. After grinding and sieving to less than 90 μm, the powders were sprayed onto aluminium panels and cured. The resins were assessed by DSC analysis and a Rheometrics viscometer, while the powder formulations were assessed visually for appearance and flow, evaluated according to the PCI scale from 1 to 10 (bad to good), acetone or ethanol rubs, mechanical and chemical test procedures, colour gloss and haze. Two powder coating formulations were prepared and assessed. PA-l is an amine functional polyamide crosslinked with blocked isocyanate (BF 1530) and PA-II is an acid functional polyamide crosslinked with an epoxy (PT-912). Both formulations contained titanium dioxide (33%) and the usual additives. After application both coatings were cured at 230°C for 2 minutes. Appearance of PA-l was good while PA-ll was only moderate. Both products passed the reverse impact test. Flow of PA-l was assessed at 8 while PAl only achieved a rating of 4. Both were comparable for gloss and haze and results were good or excellent, and comparable in all other tests. The unique advantage of polyamides over polyesters was demonstrated by a direct comparison between a polyamide PA-lll and an aliphatic polyester PE-l. In order to affect a fair comparison the acid values, functionalities and viscosities of both resins were comparable, although the Tg of PA-lll was higher at 65°C while PE-l was recorded as 43°C. The powder compositions were similar and the Tg (°C) of PA-lll was 44 compared to 30 for PE-l. Gel time testing at 180°C showed a wide divergence of 43 sec for PA-lll against 208 sec for PE-l. JULY 2009
NEW POWDER TECHNOLOGIES AND MARKET OPPORTUNITIES
JULY 2009 In this issue
TECHNICAL
2-3
Low temperature cure thermosetting polyamide resins
INDUSTRY NEWS
3-6
AkzoNobel 1Q 2009: Performance Coatings: industrial activities Kemira: Tikkurila has acquired rest of shares in its industrial coatings companies in Russia Ferro reports 1Q 2009 results: performance coatings Biotechnology and fermentation could be the way forward for coatings materials Trimite merges with Weilburger Coatings Jotun targets 8% market share
MARKETS
AN INTERNATIONAL NEWSLETTER MONITORING TECHNICAL AND COMMERCIAL DEVELOPMENTS IN POWDER COATINGS ISSN 1364–5439
6-8
The global market for high heat resistant coatings Not-so-little Italy: coatings market Coatings will ride out auto decline German powder market holds firm
Occasionally, a new aspect of thermosetting powder coatings technology is revealed with the potential to provide an additional inroad into new and profitable market opportunities. The latest development by DSM Resins of low temperature cure thermosetting polyamide resins is a significant advance in powder coatings technology and the abstracted account is, therefore, a more detailed assessment of its future role in the powder coatings industry. In the early years of thermosetting powder coatings, before the existing extruders were adapted to handle the lower viscosities and higher reactivities of thermosets, the thermoplastic polyamides or Nylon polymers were extruded at high torques and high temperatures and cut into small granules. They were unsuitable for use in powder coatings, despite the attractive features of high wear and chemical resistance, because of their high melting points, poor adhesion to metallic substrates, and difficulties in grinding these materials. Attempts to modify these materials as toughening additives in thermosetting powder formulations were unsuccessful. Now they have been re-invented by DSM Resins and I am sure that all formulators of thermosetting powders will be interested in this new binder species.
Market opportunities that have been explored by powder producers in the wide variety of high heat resistant coatings have only been partially successful. Although the demand for these coatings is increasing at almost 6% annually, the share of powder coatings is only a mere 14% of the total market and they are missing out to liquid coatings for reasons, which I find difficult to accept. It is claimed that the higher film thicknesses of powder coatings are not able to withstand the thermal stresses of high temperature service conditions when compared to the performance of thinner liquid coatings. While powder coatings are certainly more capable of applying much thicker films in one-pass applications than liquid coatings, recent advances in control of particle size distribution and lower average particle sizes, have made thin films a reality. With the advent of radiation curable powder systems possessing lower melt viscosities and enhanced film flow, there is no valid reason why formulators cannot improve their high heat resistant powders to meet the challenge of liquid coatings. In the areas of flame retardancy coatings the ability of powders to apply higher thickness one-pass films should be beneficial. Perhaps it is time to upgrade our heat resistant powder coatings to
POWDER COATINGS POWDER COATINGS POWDER COATINGS POWDER COATINGS
F O C U S include the latest technical advances! The review of latest developments in the production of nanocomposite films is included because it illustrates the use of well-established coatings technologies in the preparation of these films. We can all learn from the experiences of other industries! Sid Harris
TECHNICAL Low temperature cure thermosetting polyamide resins The application of low temperature powder coatings to heat sensitive substrates such as wood and plastics is still only a small segment of the total powder coatings market accounting for 0.1% according to DSM Resins, and powder coatings represent only 2% of coatings applied to MDF. However, the growth potential for powder coatings in this market segment has prompted DSM to develop new low temperature cure thermosetting polyamides, which is a completely new concept in powder coating binders. Thermoplastic polyamides have the unique properties of high toughness, high impact resistance and a low friction coefficient. The high wear resistance of polyamides is due to the strong hydrogen bonds between the amide groups, and this is also reflected in their good chemical resistant qualities. Thermoplastic polyamides such as Nylon-11 and Nylon-12 have not been widely used in powder coatings because of their poor adhesion to metal surfaces. They have crystalline structures and are characterized by high melting points and high molecular weights. They are also difficult to process and apply, and they possess high sensitivity to impurities. DSM has now developed amorphous polyamides 2
O N
POWDER
for use in thermosetting powder coating applications. The synthesis of these amorphous polyamides is relatively fast and uncomplicated. The DSM products are based on the combination of dibasic, mainly aliphatic, acids with diamines at temperatures below 100°C, followed by condensation and continuous removal of water of reaction at temperatures above 160°C. It is possible to control resin properties such as glass transition temperatures (Tg), functionality and viscosity due to the wide variety of raw materials available. Tg’s can be varied from –40 to 200°C with a wide range of functionalities. The ratio of the reacting monomers dictates the type of functionality, which can be either acid or amine. The amorphous nature of the polymer is assured by the choice of components that partially modify the regular structure of the polymer by the introduction of non-symmetrical monomers, such as isophorone diamines or other non-linear diamines. Experimental details are described in the recent paper presented at the European Coatings Congress. A list of twelve commercially available monomers offers a wide choice of basic raw materials. In the laboratory preparation water amine and additives are charged to the reactor and the acids are slowly added. The mixture is then heated to 220°C with removal of water and maintained at this temperature for at least 1 hour. The resin is then vacuum distilled for at least thirty minutes Special additives are incorporated and stirred in for a further thirty minutes, when the resin is discharged, and cooled. The powder coatings are then formulated according to their functionality. Acid functional polyamide resins can be cured with epoxies, TGIC or derivatives and ß-hydroxyalkylamides, while the amine functional resins, which are even more reactive than hydroxylated polyester resins, can be crosslinked by blocked
C OAT I N G S isocyanates and epoxies. The powder coatings are prepared by conventional methods using a twin-screw extruder at zone settings of 80 to 120°C and speeds in excess of 200 rpm. After grinding and sieving to less than 90 μm, the powders were sprayed onto aluminium panels and cured. The resins were assessed by DSC analysis and a Rheometrics viscometer, while the powder formulations were assessed visually for appearance and flow, evaluated according to the PCI scale from 1 to 10 (bad to good), acetone or ethanol rubs, mechanical and chemical test procedures, colour gloss and haze. Two powder coating formulations were prepared and assessed. PA-l is an amine functional polyamide crosslinked with blocked isocyanate (BF 1530) and PA-II is an acid functional polyamide crosslinked with an epoxy (PT-912). Both formulations contained titanium dioxide (33%) and the usual additives. After application both coatings were cured at 230°C for 2 minutes. Appearance of PA-l was good while PA-ll was only moderate. Both products passed the reverse impact test. Flow of PA-l was assessed at 8 while PAl only achieved a rating of 4. Both were comparable for gloss and haze and results were good or excellent, and comparable in all other tests. The unique advantage of polyamides over polyesters was demonstrated by a direct comparison between a polyamide PA-lll and an aliphatic polyester PE-l. In order to affect a fair comparison the acid values, functionalities and viscosities of both resins were comparable, although the Tg of PA-lll was higher at 65°C while PE-l was recorded as 43°C. The powder compositions were similar and the Tg (°C) of PA-lll was 44 compared to 30 for PE-l. Gel time testing at 180°C showed a wide divergence of 43 sec for PA-lll against 208 sec for PE-l. JULY 2009