ALTERNATIVE CO-SOLVENTS FOR POLYURETHANE DISPERSIONS
The co-solvent of choice for most polyurethane dispersion manufacturers until recently has been N-methyl pyrrolidone (NMP). It offers a number of very beneficial characteristics including water-miscibility, strong polarity and slow evaporation rate that are ideal properties for the processing and coalescing of water-based polyurethane dispersions. Due to concerns about worker exposure and environmental contamination in some states and regions however, producers are looking at alternative solvents with similar properties.
To address these concerns, Hauthaway has developed a line of PUD’s that uses an alternative co-solvent called dipropylene glycol dimethyl ether (DMM). This solvent is considered to have low toxicity for humans and presents far less of an environmental risk. Dow Chemical’s Safety Data Sheet states the following:
DMM has low toxicity if swallowed. Swallowing small amounts as a result of normal handling operations is unlikely to cause injury. However, swallowing larger amounts may cause injury. In laboratory animal testing, exposure to DMM is not anticipated to cause birth defects or interfere with reproduction. Genetic toxicity studies were negative.
DMM is volatile, and will evaporate from products containing it. However, because it is moderately soluble in water, once introduced, it has a tendency to remain in water. It has minimal tendency to bind to soil or sediment. DMM is unlikely to persist in the environment. DMM is inherently biodegradable, which suggests the chemical will be removed from water and soil environments, including biological wastewater treatment plants. DMM is not likely to accumulate in the food chain (bio-concentration potential is low), and it is practically nontoxic to fish and other aquatic organisms on an acute basis.
DMM, however, is not the perfect solution. It is not as effective a coalescing solvent as NMP, so hard PUD polymers will require the addition of other slow evaporating co-solvents such as dipropylene glycol monomethyl ether (DPM) or dipropylene glycol n-butyl ether (DPnB) to attain optimal film formation.
In chemical- and stain-resistance testing, the DMM-containing versions performed comparably to NMP-containing grades at the same VOC content level. The same was generally true for other properties such as abrasion- and scratch/mar-resistance.
If you are interested in evaluating alternatives to NMP-containing polyurethane dispersions, Hauthaway has a complete line of DMM products suitable for just about every application.
WATER-BASED UV-CURABLE POLYURETHANE DISPERSION
Hauthaway has introduced a new, zero VOC content, water based, UV-curable PUD for kitchen cabinet, wood flooring and plastic substrate applications, called Hauthane L-3415.
Coatings formulated with L-3415 produce hard, chemical-resistant films with resistance to a variety of automotive test reagents including the aggressive ingredients in sun tan lotion and insect repellent.
The product offers the applicator the ability to apply a coating to a substrate using conventional application techniques for water-based coatings. The coatings are then dried under ambient or force-dried conditions before exposure to UV energy.
This approach allows for the easy repair of blemishes prior to curing. It also makes the technology suitable for coatings applied to two-dimensional plastic substrates which are intended to be thermo-formed before UV-curing.
For more details please check Hauthane L-3415 Technical Data Sheet.
Bio-renewable Based Polyurethane Dispersions
Hauthaway introduced 2 new polyurethane dispersions, Hauthane L-3360 and L-3369, that are partially synthesized from bio-based raw materials. Hauthane L-3360, the softer grade, has 50% bio-renewable content.
It is suggested for applications like textile and leather topcoats, while L-3369, a medium hard grade at 42% bio-renewable content is recommended for wood and concrete flooring, as well as wood furniture. L-3369 has remarkably high alcohol resistance characteristics for a polyurethane dispersion.
For more details please check the Hauthane L-3360 technical data sheet, or Hauthane L-3369 technical data sheet.
Silicone-modified Polyurethane Dispersion
Hauthaway has introduced Hauthane L-3466, a new, higher silicone content (vs. HD-2602), polyurethane dispersion for a variety of applications requiring surface slip properties, abrasion-resistance and dye-transfer resistance.
End-use applications include flexible substrates such as leather and PVC sheet for seating surfaces to rigid substrates like wood used for kitchen cabinet finishes.
Crosslinked versions of coatings using L-3466 may be suitable for automotive interior, and for dry-erase, white board end-uses where dye-transfer resistance is a critical consideration.
For more details please check L-3466 Technical Data Sheet.
Co-solvent free, TEA-free, Tin-free, APEO-free Polyester-based Polyurethane Dispersions
The desire for cleaner and greener coatings polymers was the impetus for the development of 2 new grades that offer the formulator the ability to produce low VOC, environmentally-conscious coatings. Originally designed for the European market with its focus of applicator-friendly coatings, the products are free of co-solvent, TEA, APEO surfactants and tin. Hauthaway offers a hard grade, Hauthane L-3615, for wood, plastic and concrete end-uses, and a soft grade, Hauthane L-3614, for textile and leather applications.
Co-solvent free, APEO-free, Tin-free Polycarbonate-based Polyurethane Dispersions
Polycarbonate-based PUD’s have been around for decades (see HD-2500 series grades), but the need for lower VOC content coatings with hydrolysis resistance characteristics prompted Hauthaway to develop 2 new grades that fill a formulating gap. With Hauthane L-3528 (hard) and L-3529 (soft), Hauthaway provides the formulator with the ability to develop <100 g/l (less water) compliant coatings that stand up to environmentally challenging conditions such as high humidity and UV exposure.
Searching for that soft, silky touch for your brochure cover or package coating? Look no further. Hauthane L-3595 is the polymer of your haptic dreams. This high solids, ready-to-use polymer is perfect for many over print varnish applications where the combination of cost and performance is critical. We’ll even send you a coated card sample to evaluate yourself. Don’t go with the high priced, low solids, infrequently available alternatives. Hauthane L-3595 is the one you want!