Bulletin 2 - Alternative System Epsilon
The chemicals used for screen reclamation can be some
of the most hazardous products in a screen printing facility. Highly
volatile solvents are typically used. These cleaners may contain chemicals
that are harmful to the health of employees if inhaled, i ngested,
or absorbed through the skin. If they are not disposed of properly,
these products may also harm to the environment.
To reduce the hazards of screen reclamation to workers and to the environment, screen printers using solvents for screen reclamation should consider switching to one of the safer substitute products currently on the market. These substitutes often contain less harmful chemicals and have a lower volatile organic compound (VOC) content. With a lower VOC content, the chemical is less likely to be inhaled by employees or released to the air.
This bulletin highlights the characteristics of one type of substitute product system and compares it to a traditional (solvent-based) screen reclamation system. Specifically, this bulletin describes:
To access a table that summarizes the differences between the traditional and the alternative systems described in this bulletin, follow the links to the table found under each of the section headings.
| Initiated by industry, this project was entirely voluntary
and involved almost all sectors of the screen printing industry: manufacturers
donated their products for evaluation, staff from Screenprinting and
Graphic Imaging Association International (SGIA) coordinated the field
demonstrations, the Screen Printing Technical Foundation (SPTF) performed
initial product testing, printers nationwide evaluated the products
in their facilities, and EPA staff conducted a risk assessment of
the products. One advant age of this coordinated effort is that all
product systems were evaluated using the same methods. The consistency
of the evaluations allows you to compare the results to determine
which of the alternatives may be a viable substitute for your current
recla mation products.
This bulletin highlights one alternative system, referred to as Alternative System "Epsilon." This system, as with all systems demonstrated in this project, is a real, commercially available screen reclamation system; however, "Epsilon" is a masked name. The actual trade name for this alternative system (or for any of the alternative systems demonstrated) is not used in this bulletin or in the final project report. Trade names were masked for several reasons:
To compare the cost and risk of Alternative System Epsilon to a known system, a baseline was established using a traditional solvent-based screen reclamation system consisting of: lacquer thinner as the ink remover, a sodium periodate solution as the emul sion remover, and a xylene/acetone/mineral spirits/cyclohexanone blend as the haze remover. These chemicals were selected because screen printers indicated they were commonly used in screen reclamation. It should be noted that these technologies were eval uated using a case study approach; rigorous scientific testing was not conducted. Instead, much of the information presented here is based on printers' experiences with these products as used at their facilities.
|Performance was evaluated in two phases: 1) performance demonstrations at SPTF's laboratory under controlled conditions; and 2) field demonstrations at volunteer printers' facilities under the variable conditions of production. Since conditions vary great ly, printers felt it would be most valuable to evaluate performance based on the experiences and opinions of the experts: the printers who used the alternative products in their facilities during month-long demonstrations. Each product system was demonstr ated in two or three facilities to get a more complete evaluation of performance under a variety of operating conditions.|
|During laboratory testing, three imaged screens were reclaimed using Alternative System Epsilon: one with a solvent-based ink, the second with an ultraviolet-curable (UV) ink, and the third with a water-based ink. During the laboratory tests, the Epsilon ink remover dissolved the ink quickly, was easy to use, and removed residue from the screens with solvent-based and UV-curable inks. In both cases, a light to moderate ink stain remained on the screen. When the ink remover was used on the screen with wate r-based ink, more time and effort were needed, but the ink was removed except for a light stain. On all three screens, the emulsion remover dissolved the stencil and there was no emulsion residue on any of the screens after pressure rinsing. In the final step, the Alternative System Epsilon haze remover lightened the ink stains on all three screens.|
| Two different facilities used System Epsilon for a
month to evaluate how well it performed in a production situation.
The participating facilities recorded the amount of product used,
the length of time needed, and their opinion of how well the product
re claimed the screen. Both facilities (referred to as Facility A
and Facility B) found the product system worked well, especially the
Ink Remover Performance: At Facility A, the ink remover worked well, easily removing the solvent-based ink. However, when removing catalyzed inks, some of the workers thought that the ink remover acted more slowly and required extra effort. Facility B used the products on screens with both UV-curable and solvent-based inks. The Epsilon ink remover efficiently removed the inks; it worked especially well on the UV-curable ink. In addition, Facility B found they used significantly less alternat ive ink remover per screen than their standard product, lacquer thinner.
Emulsion Remover Performance: The emulsion remover worked very well at both facilities, dissolving the stencil quickly and easily.
Haze Remover Performance: Both facilities evaluated the haze remover performance as similar in efficacy to their standard haze removers.
Overall Evaluation: The performance of Alternative System Epsilon was good at both facilities, according to the printers' evaluations. Because the two facilities have very different operations, the fact that System Epsilon performed well at both print shops demonstrates that this system can work well under different operating conditions. Facility A prints banners and point-of-purchase displays on plastic using a variety of solvent-based inks, a dual cure emulsion, and mesh counts of 83 - 280 threads/inch. Facility B prints vinyl and mylar labels using both solvent-based and UV-curable inks. They use a direct photo stencil and screens with a mesh count of 355 threads/inch. Even with these differences, Alternative System Epsilon was successful in reclaiming screens at both facilities. The final proof for the participating printers was that all the reclaimed screens could be reused for future print jobs.
| Environmental releases and occupational risks associated
with both the Alternative System Epsilon and the traditional screen
reclamation system were evaluated. Review the table for a detailed
description of the health risks.
Whether using traditional screen reclamation techniques or an alternative system, chemicals can get into your body either through your skin when you contact the product or through your lungs when you inhale chemical vapors. Some chemicals have a lower ten dency to evaporate or to enter the body through the skin; and different chemicals have different effects, some more harmful than others, once in your body. The risks associated with inhalation of the chemicals in Alternative System Epsilon are much lower than those associated with the traditional system. With the traditional system, daily inhalation of toluene and methyl ethyl ketone in the ink remover, and acetone in the haze remover could lead to eye, nose, and throat irritation, headaches, or fatigue.
Applying either the Alternative System Epsilon or the traditional system products regularly without wearing gloves can be harmful to your health. The potential for these harmful effects through skin contact are attributed to chemicals in all the products of the traditional system (ink remover, emulsion remover, and haze remover) and to chemicals in the alternative ink remover and emulsion remover. If you wear gloves regularly, however, these risks are negligible.
|Based on the EPA assessment, none of the chemicals in either the traditional system or Alternative System Epsilon were found to be hazardous to the environment in the quantities used for screen reclamation. However, a reduction in the use of traditional s creen reclamation chemicals could cut a facility's air releases. Traditional screen-cleaning solvents often have a high volitile organic compound (VOC) content, contain Hazardous Air Pollutants regulated under the Clean Air Act, or contain a RCRA listed o r characteristic waste. Substituting an alternative product system for these traditional screen reclamation chemicals could reduce your facility's regulatory burden. Contact your state and local environmental regulatory authority for information specific to your location.|
| The demonstrations showed that both of the participating
facilities could reduce their costs for screen reclamation by switching
from the traditional system to Alternative System Epsilon. As with
the risk comparisons, costs of Alternative System Epsilon w ere compared
to the costs of using the traditional system. The cost estimate is
based on the assumption that 6 screens were reclaimed daily and that
all screens were approximately 15 ft2 in size, for both the traditional
and the alternative systems. Inclu ded in the cost estimate were:
labor time spent to reclaim the screen, the cost of an average quantity
of reclamation products, and the cost of hazardous waste disposal
for RCRA-listed or characteristic (ignitable based on flashpoint)
waste. The RCRA-list ing applies to the traditional system ink remover,
but does not apply to any part of the alternative system.
For Facility A, reclamation cost per screen would drop 51% from $6.27/screen to $3.08/screen for annual savings of $4,775. At Facility B, the reclamation cost of $6.27/screen using the traditional system would drop to 16% to $5.29/screen for the alternati ve system. Over a year, the savings at Facility B would amount to $1,469. The difference in costs between the facilities is due to differences in the quantity of product used and the labor time required per screen as recorded by each facility's employees.
| Although the alternative system described in this case
study proved to be a viable alternative in the two printing facilities
where performance demonstrations were conducted, it may not be the
solution for all types of screen printing operations. If you f ind
that Alternative System Epsilon does not seem like a feasible substitute
for your facility, refer to the summary booklet, Designing Solutions
for Screen Printers: An Evaluation of Screen Reclamation Systems,
which includes information on all the alter native product systems
and alternative technologies evaluated. When you identify a product
system that seems like a potential substitute, contact your supplier,
identify the alternative system by its chemical composition, and discuss
the characteristics o f the products you are looking for.
This bulletin is part of a series of bulletins and case studies that provide screen printers with information on products and techniques that can help them to prevent pollution in their facilities. Information in these bulletins is largely based on the wo rk done by the Design for the Environment Screen Printing Partnership. For copies of this bulletin, other DfE Screen Printing Partnership Materials, or mroe information about the project, contact:
Pollution Prevention Information Clearinghouse
Screenprinting and Graphic
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