Features

Biocides, Fungicides & Mildewcides

Whether they are keeping bacteria at bay in the can or helping the finished surface battle mildew, these additives play a key role in your formulation.

Christine Esposito08.09.05

Imagine the average DIY'er on a Saturday morning. She's finalized her plans to redecorate the study. She has spent hours watching HGTV, roaming home decor stores and taking down wallpaper. She's ready to go. But as she opens the lid, she comes face-to-face with a gallon of contaminated paint.

Luckily, this doesn't happen very often.

Whether they are keeping bacteria at bay in the can or helping the finished surface of an exterior coating or yacht paint battle mildew or fungus, biocides, fungicides and mildewcides play an essential role in paint and coatings formulations.

Protection for Paint
Companies Coatings World spoke with have been actively working on a number of new products.

Avecia Protection & Hygiene continues to extend its Proxel range of preservatives to satisfy new customer needs, according to the company. The latest additions to the range in Europe are Proxel Ultra 5 and Proxel Ultra 10-both of which are zero VOC formulations for preservation of polymer emulsions.

Avecia, which this year opened a new $4.5 million biocides R&D lab in Delaware, recently launched a new molecule, Vanquish, which was developed as a fungicide for plastics, polyolefins and polyurethanes. Vanquish also delivers powerful antifungal effects in a variety of coatings systems, according to Avecia.

The company's Vantocil IB polymeric biguanide has been developed as a hygiene aid and a preservative for coatings raw materials-including silicone emulsions, polyvinyl alcohol and polyvinyl acetate. The product combines quick kill, broad spectrum antimicrobial activity and excellent chemical stability over a wide pH range, according to the company.

Of course, the Biocidal Products Directive in Europe is changing the industry (see page 43), and companies have been forced to prepare.

"Degussa is supporting a complete line of industrial biocides under the Biocidal Products Directive in Europe. These products include industrial biocide for the protection of coatings from spoilage in the wet state and the protection of coating films from algal and fungal defacement and deterioration as well as biocides for anti-fouling applications," said Degussa's Bill Woods.

Degussa now offers two new patented combinations in its Biotrend Nuocide 2000 series. "These products (Nuocide 2002 and Nuocide 2010) offer low term cost-effective protection of coating films from defacement by fungi and algae," Dr. Woods added. Both dispersions have been formulated for easy incorporation during coatings manufacture, according to the company.

Other new products from Degussa include a pair of dispersions for use in marine antifouling coatings. Fungitrol 1052 AFD and Fungitrol 1054 AFD target soft fouling organisms. Degussa's Nuosept APC is a newly developed, patented controlled-release polymer for use as a biocide in aqueous coatings. Degussa also launched the Fungitrol 400 series, which consists of four unique formulations based on the active iodopropynylbutylcarbamate.

Following its acquisition of Swiss-based Acima last year, Rohm and Haas has been working with customers to develop more effective biocide solutions for both in-can and dry film product preservation.

"These Acima formulations will be sold under the Rocima trademark. EPA approval is expected in late 2001 for several of the Rocima products," said David Sutton, global communications manager for consumer and industrial specialties at Rohm and Haas.

Like Rohm and Haas, The Dow Chemical Company has also bolstered its position in the biocides market thanks to the acquisition of Angus Chemical Co. and its more recent merger with Union Carbide.

"The biocides industry traditionally has been very fragmented with over 45 producers in the market, each doing their own thing with just one or two chemistries," said Janet Mann, global business director, Dow Biocides. By combining the best characteristics of the three companies, Ms. Mann contends, Dow has been able to create one of the broadest registered product lines in the industry.

Troy Corp.'s offerings include Polyphase 641, a long-term fungal and mildew protection with maximum compatibility and chemical and heat stability. Suitable applications include architectural coatings, wood coatings and marine coatings.

The Florham Park, NJ-based firm also offers Polyphase 600, a broad-spectrum algicide, fungicide, and mildewcide for waterborne and solvent-based systems and Polyphase CST, a color stable fungicide and mildewcide for cost-effective protection and superior gloss retention. Polyphase can be formulated into a wide variety of coatings for architectural, wood and marine applications.

As this issue went to press, Troy announced that Polyphase 659, its low-VOC dispersion for fungal and algal protection in water-based systems, earned EPA approval.

Arch Chemicals has received EPA registration for a fungicide-algicide specially formulated for use in masonry paint. Zinc Omadine ZOE dispersion, the latest addition to Arch's Omadine product line of broad-spectrum antimicrobials, is effective under the higher pH conditions of masonry coatings. It also offers benefits of low water solubility, low leachability and alkaline stability.

"Our Zinc Omadine ZOE dispersion continues to show strong growth in European and Asian markets because it meets performance needs of these regional paint formulators," said Douglas K. Simpson, global business manager for Arch's industrial biocides. "For the U.S. market, especially in the south and southeast, the increased use of cementitious materials, such as stucco, for building facades will require specialized biocides like ZOE."

Buckman offers Busan 1440, a 40% active IPBC broad-spectrum fungicide for solvent and waterborne paints and stains. It can be added to natural and synthetic adhesives and caulks for non-medical/nonfood use and also in water-based ink solutions and plastics items. In addition, the company offers Busan 1292 and Busan 1078. 1292 is a 24% active propiconazole-based film preservative for solvent- and water-based coatings, clear finishes and wood protective coatings to protect against mold growth. Busan 1292 offers low worker and environmental toxicity. 1078, which is EPA registered, is a non-formaldehyde, in-can preservative that controls bacteria in water-based coatings, adhesives and architectural materials.

A Heavenly Find: Tnemec To Harness Power of
Bleach in Coatings

Tnemec's customers wanted an antimicrobial coating for sanitary environments that could withstand severe and repeated cleaning. As the Kansas City, MO-based coatings company searched for a solution, it found traditional antimicrobial additives weren't up to the task.

"For several years, we evaluated antimicrobial additives for coatings and determined there were several drawbacks to the products currently available. In many cases, the additives offered varying degrees of effectiveness and lost potency throughout their lives, mainly from severe cleaning procedures," said Mark Thomas, manager of product marketing, Tnemec.

But like a message sent from above, Tnemec found what it was looking for in haloshield, a new technology from Halosource of Seattle, WA. "The beauty of haloshield is it utilizes the effectiveness of chlorine bleach, a widely used and trusted biocide, by anchoring the chlorine molecules to the coating's surface," Mr. Thomas said.

According to Tnemec and Halosource, coatings containing haloshield can be easily "recharged" by routine cleaning with a solution of chlorine.

How? Haloshield acts like a receptor or socket for chlorine to create a surface that has antimicrobial properties when rinsed or wiped with chlorine bleach, according to Jeff Williams, chief technical officer at Halosource.

"The great thing about chlorine compared to other biocides or fungicides is that it kills faster and affects a broader spectrum of organisms. Our technology allows the chlorine to systematically kill microbes that come into contact with a surface," said Mr. Thomas.

According to Dr. Williams, haloshield, which was born from research conducted at Auburn University and the University of California, has potential for use in powder coatings to copolymers. "It provides power to the surface. It's hard to do this without weakening the biocide-you can't get enough horsepower. With haloshield, it becomes a kill-on-contact surface."

Tnemec, which has exclusive rights under a multi-year licensing agreement, plans to incorporate haloshield technology into a new line of advanced coating systems. The line is expected to launch in 2002 after field trials are completed. "We expect the coatings containing haloshield to be very attractive to our customers, especially considering the unique safety benefits that come with maintaining a sanitary environment," Mr. Thomas said.

Germ Warfare
While the performance of biocides, fungicides and mildewcides in paint goes virtually undetected by most consumers, attitudes are changing. It appears that "germ warfare" is trickling down from personal care to home repair.

"Society has become much more germ conscious," said David Fuller, vice president of marketing for DAP, which now offers Kwik Seal Plus kitchen and bath adhesive caulk with Microban antimicrobial protection.

Antimicrobials AM 1860 and AM 500, a water-based system, from BioShield Technologies, Inc. have received additional approvals for use paints and coatings, according to the Norcross, GA-based company.

If recent launches like Kwik-Seal Plus are any indication, antimicrobials will be making their way into more paint formulations.

"Market research tells us that the antimicrobial category is seeing tremendous growth due to consumer concern over bacteria, and 83% of consumers think it is very important to have antibacterial protection in solid products," said Mr. Fuller. "DAP is responding to those concerns." CCE