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Price increases cause concern
FOCUS ON P O W D E R C O AT I N G S A MONTHLY REPORT FROM SID HARRIS JULY 2005
AN INTERNATIONAL NEWSLETTER MONITORING TECHNICAL AND COMMERCIAL DEVELOPMENTS IN POWDER COATINGS ISSN 1364–5439
PRICE INCREASES CAUSE CONCERN
In this issue
TECHNICAL
2-5
Crosslinkers for UV powder coatings
INDUSTRY NEWS
5-7
Akzo Nobel inaugurates production facility for acrylatebased powder coatings Company profile: Grebe in Weilburg. Internationally represented Company profile: Frei in Braeunlingen. Main focus on powder coatings
PRODUCTS
7
Powder coating additives: Sachtleben A major breakthrough in corrosion resistance for automobiles
MARKETS
7
Powder market to grow as demand shifts to Asia JCW spotlight: fine chemicals – paint and coatings – putting teeth in development
EVENTS
8
It was a general consensus amongst exhibitors at the 8th Nurnberg Show that raw material prices were the prime concern of the coatings industry. One exhibitor felt that prices had been a problem for so long that there had been a lack of investment in the industry since the year 2000. Others admitted that they were seriously looking for manufacturing opportunities in China, and a recent report from Belgium implied that their coatings industry could move to cheaper locations in Eastern Europe. In the words of another exhibitor “costs are like grass. You cut it every week”. Despite this sombre note, a more positive attitude was evident among the exhibitors who introduced a wide range of new products that included a number of green products in anticipation of impending environmental legislation. While there may be some despondency about trading conditions, there is no sign of complacency as the industry strives to come to terms with its current problems. Continuing refinements to the UV curing powder systems have now resulted in a system in which the binder resin is unsaturated polyester combined with a new crosslinking agent. Existing binder systems for UV cure generally rely upon two binders and so far all of these systems have limited
applications. The work carried out at Perstorp Speciality Chemicals is more akin to the construction of thermosetting powder coatings where the major binder resin determines the properties of the coating, while the crosslinker controls the network density. The major binder resin can be formulated to include the desirable qualities found in conventional powder coatings with unsaturation introduced by maleic/fumaric moieties. The paper presented at the recent Nurnberg Congress considers both unsaturated amorphous and amorphous-crystalline polyesters and evaluates a number of potential crosslinking agents. One of these crosslinkers, a new diacrylate, has been found to have a positive influence on commercial systems by improving the flow and crosslinking density. A well presented paper that will be of interest to all formulators. The second abstracted item is an article by Dr Thomas Brock. It is an elaborate account of all known aspects of new developments that could drastically change the way in which coatings are formulated in future. While it covers all areas of coatings technology it does stress the potential for powder coatings to assume a dominant role in many major industrial coatings applications. The article also
POWDER COATINGS POWDER COATINGS POWDER COATINGS POWDER COATINGS
FOCUS discusses trends in application techniques, colour and effect coatings, energy saving systems and possible solutions to problems of coating difficult substrates. It is a lengthy abstract but it makes interesting reading if only to confirm that the coatings industry is alive to the task of complying with the modern needs of their customers. Some interesting items in industry news include the inauguration of an acrylic powder coatings manufacturing unit at the Bensheim site, company profiles on two German powder producers, and Dow Chemicals’ commitment to global growth in the coatings industry. In the markets section, the ChemQuest group predicts continuing growth in the coatings industry as major producers switch to the Far East. RadTech Europe 05 will be held in Barcelona, Spain on 18-20th October 2005, and it consists of a three-day conference and exhibition. It will be a venue for some powder producers since it is a complementary coatings technology that has many aspects that are allied to powder technology, including papers relating specifically to powder coatings. Sid Harris
TECHNICAL Crosslinkers for UV powder poatings A paper presented at the recent 8th Nurnberg Congress by Mircea Manea of Perstorp Speciality Chemicals introduces a new approach to the formulation of UV powder coatings that is closer to the formulating concept for thermosetting powder coatings, in which the major binder resin is an unsaturated polyester combined with a designed crosslinking agent. As an
2
ON
POWDER
example, the paper describes a polyester based on the usual components of neopentyl glycol, terephthalic acid and isophthalic acid with the addition of the unsaturated maleic anhydride. Four crosslinkers are studied in this paper and three of them are fully described together with their method of preparation. The first of these crosslinkers is pentaspiroglycol di-acrylate (PSGdi-acrylate) prepared from the reaction of pentaerythritol and hydroxyl-pivalic aldehyde combined with ethyl acrylate that is re-crystallised to give a material of 98% purity. A second variant is pentaspiroglycol diallylether (PSGdi-allylether) prepared by reacting pentaspiroglycol and allyl chloride to give a product of 97% purity. A third crosslinker is zinc acrylate prepared by the reaction between acrylic acid and zinc oxide to give a product containing 31% Zn. The fourth material described is hexahydro-1,3,5-tris(1-oxo-2propenyl)-1,3,5-triazine, a product supplied by Daito Chemix Corp under reference M-1530. An evaluation of the crosslinking performance was made using blends at different mole ratios of the double bond in the polyester versus the acrylic unsaturation in the crosslinker. The performance was monitored by UV-FTIR, UV Rheology and UV-DSC testing procedures. Data for all these tests are given in the paper, including the rheology test that was newly developed for these evaluations. Further trials were carried out with commercial UV resins produced by Perstorp. The results showed that PSGdiacrylate has a positive effect on commercial systems by improving the flow and crosslinking. This material is rated as having the highest UV-DSC reactivity in powder coatings formulations, followed by Zn-acrylate, while the lowest reactivity was shown by the M-1530. The PSGdi-allylether gives no crosslinking. The high reactivity of the PSG-diacrylate
C OAT I N G S can also be seen in the UVrheology tests. The onset time is little longer than that of the M1530, but the network is more crosslinked. The Zn-acrylate is slower to crosslink than the M1530 at the beginning but shows both lower phase degree and higher values in the described Stresstech test. UV-FTIR gives only small changes during the curing. It is concluded that a UV curable polyester may be easily formulated, using as a starting point any unsaturated polyester of maleic/fumaric type. It has been shown that addition of a small quantity of PSG-diacrylate may improve the performance in commercial systems of lower reactivity. The achieved level of the crosslinked systems in terms of double MEK rubs and Tg of cured film strongly recommend this approach as a reliable option in UV powder coating formulations. The approach makes possible the use of typical unsaturated polyesters as binders in powder coatings formulations. Paper entitled “Crosslinkers for UV Powder Coatings” presented by Mircea Manea of Perstorp Speciality Chemicals AB, Sweden, included in the 8th Nurnberg Congress on 25-26 Apr 2005. Bound copies of the Congress papers are available from the organizers: Vincentz Verlag or as a CD including both Volumes 1 and 2. Contact the Vincentz Network, PO Box 62 47, 30062, Hannover, Germany
Trends in coatings technology An interesting article describing the future trends in coatings technology considered the essential innovations in the development of industrial coatings and paints, based on new findings of physical and chemical basic research. The driving force is claimed to be the new substrates that will need to be coated, such as light weight magnesium alloys for automotive and airplanes that are regarded as difficult substrates because of their microporosity and the specific requirement for
JULY 2005
AN INTERNATIONAL NEWSLETTER MONITORING TECHNICAL AND COMMERCIAL DEVELOPMENTS IN POWDER COATINGS ISSN 1364–5439
PRICE INCREASES CAUSE CONCERN
In this issue
TECHNICAL
2-5
Crosslinkers for UV powder coatings
INDUSTRY NEWS
5-7
Akzo Nobel inaugurates production facility for acrylatebased powder coatings Company profile: Grebe in Weilburg. Internationally represented Company profile: Frei in Braeunlingen. Main focus on powder coatings
PRODUCTS
7
Powder coating additives: Sachtleben A major breakthrough in corrosion resistance for automobiles
MARKETS
7
Powder market to grow as demand shifts to Asia JCW spotlight: fine chemicals – paint and coatings – putting teeth in development
EVENTS
8
It was a general consensus amongst exhibitors at the 8th Nurnberg Show that raw material prices were the prime concern of the coatings industry. One exhibitor felt that prices had been a problem for so long that there had been a lack of investment in the industry since the year 2000. Others admitted that they were seriously looking for manufacturing opportunities in China, and a recent report from Belgium implied that their coatings industry could move to cheaper locations in Eastern Europe. In the words of another exhibitor “costs are like grass. You cut it every week”. Despite this sombre note, a more positive attitude was evident among the exhibitors who introduced a wide range of new products that included a number of green products in anticipation of impending environmental legislation. While there may be some despondency about trading conditions, there is no sign of complacency as the industry strives to come to terms with its current problems. Continuing refinements to the UV curing powder systems have now resulted in a system in which the binder resin is unsaturated polyester combined with a new crosslinking agent. Existing binder systems for UV cure generally rely upon two binders and so far all of these systems have limited
applications. The work carried out at Perstorp Speciality Chemicals is more akin to the construction of thermosetting powder coatings where the major binder resin determines the properties of the coating, while the crosslinker controls the network density. The major binder resin can be formulated to include the desirable qualities found in conventional powder coatings with unsaturation introduced by maleic/fumaric moieties. The paper presented at the recent Nurnberg Congress considers both unsaturated amorphous and amorphous-crystalline polyesters and evaluates a number of potential crosslinking agents. One of these crosslinkers, a new diacrylate, has been found to have a positive influence on commercial systems by improving the flow and crosslinking density. A well presented paper that will be of interest to all formulators. The second abstracted item is an article by Dr Thomas Brock. It is an elaborate account of all known aspects of new developments that could drastically change the way in which coatings are formulated in future. While it covers all areas of coatings technology it does stress the potential for powder coatings to assume a dominant role in many major industrial coatings applications. The article also
POWDER COATINGS POWDER COATINGS POWDER COATINGS POWDER COATINGS
FOCUS discusses trends in application techniques, colour and effect coatings, energy saving systems and possible solutions to problems of coating difficult substrates. It is a lengthy abstract but it makes interesting reading if only to confirm that the coatings industry is alive to the task of complying with the modern needs of their customers. Some interesting items in industry news include the inauguration of an acrylic powder coatings manufacturing unit at the Bensheim site, company profiles on two German powder producers, and Dow Chemicals’ commitment to global growth in the coatings industry. In the markets section, the ChemQuest group predicts continuing growth in the coatings industry as major producers switch to the Far East. RadTech Europe 05 will be held in Barcelona, Spain on 18-20th October 2005, and it consists of a three-day conference and exhibition. It will be a venue for some powder producers since it is a complementary coatings technology that has many aspects that are allied to powder technology, including papers relating specifically to powder coatings. Sid Harris
TECHNICAL Crosslinkers for UV powder poatings A paper presented at the recent 8th Nurnberg Congress by Mircea Manea of Perstorp Speciality Chemicals introduces a new approach to the formulation of UV powder coatings that is closer to the formulating concept for thermosetting powder coatings, in which the major binder resin is an unsaturated polyester combined with a designed crosslinking agent. As an
2
ON
POWDER
example, the paper describes a polyester based on the usual components of neopentyl glycol, terephthalic acid and isophthalic acid with the addition of the unsaturated maleic anhydride. Four crosslinkers are studied in this paper and three of them are fully described together with their method of preparation. The first of these crosslinkers is pentaspiroglycol di-acrylate (PSGdi-acrylate) prepared from the reaction of pentaerythritol and hydroxyl-pivalic aldehyde combined with ethyl acrylate that is re-crystallised to give a material of 98% purity. A second variant is pentaspiroglycol diallylether (PSGdi-allylether) prepared by reacting pentaspiroglycol and allyl chloride to give a product of 97% purity. A third crosslinker is zinc acrylate prepared by the reaction between acrylic acid and zinc oxide to give a product containing 31% Zn. The fourth material described is hexahydro-1,3,5-tris(1-oxo-2propenyl)-1,3,5-triazine, a product supplied by Daito Chemix Corp under reference M-1530. An evaluation of the crosslinking performance was made using blends at different mole ratios of the double bond in the polyester versus the acrylic unsaturation in the crosslinker. The performance was monitored by UV-FTIR, UV Rheology and UV-DSC testing procedures. Data for all these tests are given in the paper, including the rheology test that was newly developed for these evaluations. Further trials were carried out with commercial UV resins produced by Perstorp. The results showed that PSGdiacrylate has a positive effect on commercial systems by improving the flow and crosslinking. This material is rated as having the highest UV-DSC reactivity in powder coatings formulations, followed by Zn-acrylate, while the lowest reactivity was shown by the M-1530. The PSGdi-allylether gives no crosslinking. The high reactivity of the PSG-diacrylate
C OAT I N G S can also be seen in the UVrheology tests. The onset time is little longer than that of the M1530, but the network is more crosslinked. The Zn-acrylate is slower to crosslink than the M1530 at the beginning but shows both lower phase degree and higher values in the described Stresstech test. UV-FTIR gives only small changes during the curing. It is concluded that a UV curable polyester may be easily formulated, using as a starting point any unsaturated polyester of maleic/fumaric type. It has been shown that addition of a small quantity of PSG-diacrylate may improve the performance in commercial systems of lower reactivity. The achieved level of the crosslinked systems in terms of double MEK rubs and Tg of cured film strongly recommend this approach as a reliable option in UV powder coating formulations. The approach makes possible the use of typical unsaturated polyesters as binders in powder coatings formulations. Paper entitled “Crosslinkers for UV Powder Coatings” presented by Mircea Manea of Perstorp Speciality Chemicals AB, Sweden, included in the 8th Nurnberg Congress on 25-26 Apr 2005. Bound copies of the Congress papers are available from the organizers: Vincentz Verlag or as a CD including both Volumes 1 and 2. Contact the Vincentz Network, PO Box 62 47, 30062, Hannover, Germany
Trends in coatings technology An interesting article describing the future trends in coatings technology considered the essential innovations in the development of industrial coatings and paints, based on new findings of physical and chemical basic research. The driving force is claimed to be the new substrates that will need to be coated, such as light weight magnesium alloys for automotive and airplanes that are regarded as difficult substrates because of their microporosity and the specific requirement for
JULY 2005