Formulators have spent years working around VOC limits, trading off performance for compliance one ingredient at a time. A new solvent is designed to remove that compromise altogether.

The solvents that clean well, carry fragrance and keep surfactants in check tend to be the biggest drag on a product’s VOC limit, and those limits keep getting tighter. Every reformulation becomes a balancing act between what works and what’s allowed.

Japan’s Kuraray has developed a solvent to help with that trade. Called IPD-AC, it is very similar in composition to a solvent many formulators already use. Its vapor pressure is low enough that it falls outside the VOC count under California Air Resources Board (CARB) rules.

CBC America is launching the product in the U.S. and Canada. The company is part of Tokyo-based CBC Group, founded in 1925, which has more than 40 offices around the world. CBC America has been in the U.S. since 1970, with headquarters in Manhattan and warehouses in Union, New Jersey, and Atlanta.

Jeff Crawford is a development manager in the company’s chemicals and pharmaceuticals group. “Mostly what we get involved with is import, export and distribution, and I am part of the chemicals group that does the import, export and distribution here in the U.S. and Canada,” Crawford said.

Building on a 40-year track record

The IPD-AC story starts with an older Kuraray product. Methoxymethylbutanol, or MMB, has been on the market for decades, and CBC America has imported it for more than 20 years.

“It’s been in existence for well over 40 years,” Crawford said. “It’s a workhorse solvent. It does a great job in a wide variety of cleaning products, but it does contain a VOC.”

MMB shows up in a very wide range of product categories. “Your hard surface cleaners, your window cleaners, glass cleaners, carpet cleaners, laundry detergents, car wash products. It works in a wide variety of products,” Crawford explained. It has very low odor, mixes easily with water and is water white, so it adds no cloudiness or color.

That one VOC issue sent Kuraray’s chemists back to work. “They went back to the drawing board, and they have formulated a new solvent,” Crawford noted. The new solvent, IPD-AC, “works similar to the MMB material,” he added. With its very low vapor pressure, it is classified as non-VOC under CARB rules.

For CBC America, that opens up a much wider market. Crawford said current and potential customers can now formulate products that meet VOC requirements in every state, including California, as well as in Canada. Formulators still need to check each finished product against the rules where it will be sold, since the other ingredients in a formula count, too.

Fragrance that smells true

Air care is probably the most obvious application for the new solvent. IPD-AC has essentially no smell of its own, so it stays out of the way of the scent a manufacturer is trying to deliver.

“If you’re making a reed diffuser, the IPD-AC has zero odor, so you can mix this with your fragrances, and you get a true smell, like a cherry, or a lemon, or lavender, something like that,” Crawford said. Candles benefit for the same reason.

IPD-AC evaporates slowly and releases along with fragrance oils rather than ahead of them, which lets the manufacturer control how fast a reed diffuser or plug-in gives off its scent. Kuraray brought in three professional perfumers to rate fragrance strength near the bottle, diffusion at a distance and how closely the result matched the original fragrance. IPD-AC performed well across all the fragrance types tested. It is also stable in air, so it doesn’t break down over time.

Candle makers should be aware of one thing. In Kuraray’s testing, IPD-AC performed well in soy wax but was compatible with paraffin wax only at low levels.

Stronger cleaning, and a limonene stretch

On the cleaning side, Kuraray compared IPD-AC with a butyl glycol solvent on stainless steel test pieces coated with flux or water-soluble cutting oil and heated to 200 degrees Celsius. IPD-AC gave better cleaning results on both soils.

The solvent may also ease a supply problem. D-limonene has become expensive and difficult to source. “Some cases I’ve heard over $7 a pound,” Crawford said. In Kuraray’s testing, a 50-50 mix of d-limonene and IPD-AC gave the best cleaning performance of the ratios tried. Because IPD-AC adds no odor, the blend keeps the orange scent customers expect.

IPD-AC dissolves nonionic, anionic and cationic surfactants well. Of the solvents Kuraray tested, it produced the lowest viscosity in nonionic surfactant systems, which makes the finished product easier to pump and transfer. It has little effect on polycarbonate, acrylic resins or urethane, fluorine and silicone rubber seals, and it can be stored in a wide variety of plastic bottles.

Getting more from the preservative

One of the more surprising results involves preservatives. In Kuraray’s testing against mold, adding IPD-AC alongside an isothiazolinone-type preservative sharply reduced microbial counts. The amount of preservative required could drop by as much as 80% in that testing, which points to a significant cost saving. The solvent appears to work by spreading over the surface of the cell membrane and lowering surface tension, which allows the preservative to penetrate and do its job.

“It has some very, very good antifungal and antibacterial properties,” Crawford said. Manufacturers should view this as a way to make a formula more efficient. Any germ-killing claim on a finished product label comes with its own set of regulatory requirements.

Watch the concentration in water

IPD-AC does have an Achilles’ heel. In water-based systems it can hydrolyze, so Crawford suggests keeping the concentration low, possibly under 10%.

“That’s something you’re going to have to formulate with yourself and do your own testing to see where it comes in for you,” Crawford said.

How to get samples

IPD-AC is made in Japan, and CBC America plans to stock it in drum quantities at both its New Jersey and Atlanta warehouses. Samples are available now, along with recommended starting formulations for reed diffusers, plug-ins, aerosols and candles. Manufacturers can request samples at cbcamerica.com under the Chemicals section.

Crawford sees the timing as ideal for the cleaning market in particular. “We feel we’ve got the right product for the right time for this market,” he said.

Learn more on the CBC America website here.