Microbe management.

Increasingly strict regulations covering both coatings and biocidal actives have placed manufacturers of antimicrobials in a difficult position. The paint formulations being developed today are more susceptible to microbial attack, requiring broader spectrum control. At the same time, several biocides in use have been shown to have questionable safety and environmental profiles, at least in some geographic regions. Producers have responded by developing "greener" formulations of existing biocides and investigating new combinations of actives to address the more complex needs of customers while meeting the requirements of regulatory agencies and the growing expectations of consumers for more sustainable (but no less antimicrobial) coating products.

[ILLUSTRATION OMITTED]

The global market for biocides used as dry film or in-can was estimated to be $455 million in 2008 (see Table 1), according to market research firm Kusumgar, Nerlfi & Growney (KNG). Demand is expected to decline approximately 3% in 2009 as the paint and coatings market contracts. Currently, dry film products account for 55% of the market in value terms.

Table 1--Coating Biocide Consumption by Region in 2008 ($MM)

Type/Region                 North    Europe  Asia  Rest of  Total
                           America                  World

Dry film and preservative    150      175     100     30     455

Marine, excluding cuprous      6       15      77      7     105
oxide (a)

Total                      156      190       177   37       560

(a) Cuprous oxide, nearly 120 MM lb in 2008; price varies with copper
price.

Source: Kusumgar, Nerlfi & Growney

Consumption of biocides in marine coatings totaled $105 million in 2009. KNG expects demand will rise by 5% in 2009, but then drop after 2010 due to a decline in world trade and new ship orders.

Leading suppliers of biocides for paints and coatings include Arch Chemicals, International Specialty Products (ISP), Dow Microbial Control (formed from the combination of Dow Biocides and Rohm and Haas Company biocides businesses), Troy Corporation, Thor Specialties, and Lanxess (see Table 2).

There are several key selection criteria that paint manufacturers consider when choosing a particular biocide. "Regulatory approvals, environmental impact, antimicrobial activity, low toxicity, and VOC content (if any) top the list," states Mike Growney, a principle consultant with KNG. "Interestingly, only one of those factors is related to the performance of the biocide." Other factors include stability, effective concentration required, cost (as used), coating formulation compatibility, and ease of use.

Table 2--Leading Global Suppliers of Coating Biocides

Company                Market Share (%)

Arch Chemicals                16

ISP                          14-15

Dow Microbial Control        14-15

Troy Corporation              11

Thor Specialties               9

Lanxess                        7

Source: Kusumgar, Nerlfi & Growney

Environmental and regulatory concerns dominate the criteria list for a reason. Compliance with VOC limits in the United States and the Biocidal Products Directive (BPD) and REACH legislation in Europe are driving much of the formulation development that is occurring today. Even in emerging regions, where the market is growing most rapidly, the transition to water-based systems is a key driver for that growth.

Competition will be fierce as market leaders look for ways to grow their shares. They will also face different challenges depending on the region. In Europe, for example, consolidation of both product formulas and companies will likely occur in response to the dramatically increased regulatory costs. "The ability to identify products as 'green' or 'antibacterial' will help these leaders to differentiate themselves and take share from competitors. For innovative companies, double digit growth--at the expense of their competition--is possible," believes Donald A. Shaw, vice president of development for Troy Corporation. Consolidation of the customer base is also forcing a certain level of interregional harmonization of biocidal usage, according to Celso Magri, strategic marketing manager for material protection with Dow Microbial Control.

"Green" products are zero VOC with lower toxicity or better safety profiles for both humans and the environment. It also means products with a reduced carbon footprint--such as higher concentration products, products made using renewable resources, etc.

Antimicrobial, or antibacterial, products are in demand from consumers, who have become more aware of health issues, possibly because of the recent threats of potential pandemics, according to Shaw. "Our customers, in response to this growing awareness of health issues among consumers, want to be able to identify their products as 'antibacterial'."

"Increased regulatory scrutiny, public perception, and competition are all playing major roles in the evolution of biocide product offerings," observes Greg Hertenberger, manager of sales development for Industrial Biocides with ISP Performance Chemicals. "At the same time, the high costs involved in registering new actives are hindering the introduction of vital technologies the market requires and, at times, raising costs beyond a point where they are viable in the coatings market."

The proliferation of regulations around the world will continue to dramatically limit the availability of chemistry choices, agrees Shaw. "The multi-billion dollar overall investment required for regulatory compliance will deplete the dollars available for investment into new technologies. Overall, this will force companies to offer the same set of chemistries--those which have passed the regulatory hurdles and have demonstrated their value to the marketplace through years of performance. We already see this with the rapid increase in companies offering products based on IPBC or BIT."

In addition, certain actives such as carbendazim and diuron, which have found widespread use in blends, have come under increasing serutiny because of California Proposition #65 and the EU's Biocidal Products Directive, according to Hertenberger, although they remain a key technology in Southeast Asia and Latin America. There has also been pressure on formaldehyde releasers in Western Europe, North America, and Japan, but they continue to be acceptable in developing regions.

Add to these issues the fact that the continued shift to waterborne products and elimination of harmful components in all paint formulations has made these products more susceptible to microbial contamination. There has also been a growing microbial resistance to some biocides in use today, which presents yet another challenge.

"In response to this situation, we are seeing a strong move towards more sophisticated biocide formulations based on multiple actives that can cope with the microbial challenge, yet have minimal environmental impact and are safe for users," notes Magri. Emphasis on improving plant hygiene to avoid contamination from process water, raw materials, and other items is also driving demand for formaldehyde-free sanitizers.

Increasing complexity of microbial control due to technology and regulatory changes makes it difficult for paint formulators to find a suitable biocide solution. "No single active biocide can cope with today's microbial challenges while complying with all safety and environmental labels," asserts Magri. Therefore, local technical and regulatory support from a reliable partner is becoming more important for paint companies.

Dow Microbial Control uses technology to help customers optimize formulations. Its Taunovate high throughput testing capability enables the company to test numerous actives and blends to solve its customers' unique challenges. "We believe we are well positioned to help customers choose the right active or active combination to achieve mold-resistant and antimicrobial properties, as well as reduce VOC and odor concerns," Magri says.

Recently, the company introduced new antimicrobials for industrial water-based products. Bioban[TM] IPBC 40 LE and Bioban Ultra Bit 20 LE control bacteria, yeasts, and fungi and are low VOC, low viscosity, clear, function over a wide pH range, have a low freezing point, and are freeze-thaw stable and formaldehyde-free. Rocima[TM] 586 Industrial Microbiocide is a VOC-free, broad spectrum preservative that offers fast acting ability, two different modes of biocidal activity for increased microbial protection, and has clearances with the FDA and BfR.

Troy Corporation has also launched new products, targeting potential growth areas in the market. Mergal 753 is a zero-VOC, solvent-free, high concentration BIT dispersion that, according to Donald Shaw, offers the smallest carbon footprint of any wet-state preservative product available. Troysan 1050 is the first product in the company's new line of antibacterial materials for dry film protection and works against gram positive bacteria, gram negative bacteria, and MRSA (Methicillin resistant Staphylococcus aureus). It can be incorporated into a variety of coating types, making it applicable for walls, ceilings, counters, floors, and many other surfaces.

ISP has also launched new zero-VOC biocide dispersions. Fungitrol 940 is a 40% IPBC dispersion. Nuosept BMC 422, a BIT/MIT CIT/MIT, and Nuosept W, a Bronopol/CIT/MIT blend for lower pH formulations as well as inks and adhesives applications, are both no-VOC non-formaldehyde preservatives.

For a list of the common coating biocides, see Table 3.

Table 3--Common Coating Biocides

Dry Film Biocides                                         CAS #

3-Iodo-2-propynyl butyl carbamate (IPBC)                55406-53-6

2-n-octyl-4-isothiazolin-3-one (0IT)                    26530-20-1

4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DC0IT)     64359-81-5

Tetrachloroisophthalonitrile (chlorothaloniL)            1897-45-6

N-(trichloromethylthio)phthalimide(Folpet)                133-07-3

Carbendazim                                             10605-21-7

Zinc pyrithione (ZPT)                                   13463-41-7

In-Can Preservatives                                      CAS #

5-ChLoro-2-methyl-4-isothiazolin-3-one (CMIT)           26172-55-4

2-methyl-4-isothiazolin-3-one (MIT).                     2682-20-4

l,2-Benzisothiazolin-3-one(BIT)                          2634-33-5

4,4-dimethyloxazolidine/ formaldehyde adduct            51200-87-4
(Oxazotidine)

2-hydroxymethylamino ethanol/ formaldehyde adduct       34375-28-5

2-Bromo-2-nitro-1,3-propanediol (BMPD):Bronopol            52-51-7

1,5-Pentanedial:GlutaraLdehyde                            111-30-8

l-(3-chloroallyl)-                                       4080-31-3
3,5,7-triaza-1-azodiadamantanechloride (Dowicil 75)

Marine Antifoulant Biocides                                 CAS #

Zinc pyrithione (ZPT)                                   13463-41-7

Copper pyrithione (CPT),                                14915-37-8

4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (Sea Nine)  64359-81-5

Butyl-N-cyclopropyl-6-(methylthio)-                     28159-98-0
1,3,5-triazine-2,4-diamine (Irgarol 1051).

3-(3,4-dichlorophenyl)-1,1-dimethylurea(Diuron)           330-54-1

Dichloftuanid (e.g., PreventolA 4-S from Lanxess)        1085-98-9

Tolyfluanid (e.g., Preventol A 5-S from Lanxess)          731-27-1

Pyridine-triphenylborane.                                 971-66-4

Source: Kusumgar, Nerlfi & Growney

In the coming years, most producers expect a long-term shift away from formaldehyde donors and legacy chemistries. "Despite the current economic slowdown and the significant decline in paint and coatings demand, a move to replace legacy biocides in existing formulas with greener-type products is underway, creating growth opportunities through technology conversion," states Hertenberger. New product launches focused on eco-friendly paint will create additional growth potential. "Successful biocide manufacturers will develop product formulations that address constantly evolving performance requirements, ever more stringent environmental regulations, and growing consumer expectations," Hertenberger concludes.

by Cynthia Challener

JCT COATINGS TECH

Contributing Writer