Question: Is polyurea UL approved? If not, is it possible to get it underwritten for
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Answer:First off, "polyurea" is a generic term used to describe a type of
technology. This is the same as "epoxy" and "polyurethane" for other types
of technologies. As there are numerous formulation possibilities for
polyurea systems, which include spray, joint sealants, aromatic and
aliphatic based, it is not possible to get "polyurea" approved through UL or
any other certification system. It would be appropriate to achieve certain
approvals on specific formulations / product trade names.
In this case, I assume that you are referring to UL approval from the
standpoint of fire rating. At this point, we are not aware of any polyurea
system where the sole material has the UL approval. There is a "coating
system" that does have approval. This is comprised of an aromatic polyurea
base coat with a top coat of a moisture cured polyurethane system. This is
being supplied by one of the PDA Member companies.
In addition, there are two aromatic based polyurea systems that have the UL
ANSI/NSF-61 potable water approval. This does not mean that "polyurea" is
approved, but these 2 specific systems / formulations are.
It would be possible to receive the UL rating for insurance purposes that
you are referring to. It would be up to the individual "polyurea" system
supplier to submit for this testing and then follow the guidelines for
application / installation. Unfortunately, the Polyurea Development
Association is not in a position to submit and receive such approvals.
2.
Question: I'm coating an existing floor and will have limited time to prep. I
have one evening to clean and prep the floor as well as fill
in numerous pitted areas. The pits are up to 1/4 inch deep. What suggestions
do you have for a material that will fill in those pits and cure very
rapidly. I am looking for the fastest method I can use to patch this rather
large areas.
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Answer:At least 70% of all coating / lining application
failures over concrete are due to poor or improper surface preparation. This is a true statement that is discussed in many of the NACE, SSPC and ICRI courses on concrete coatings work.
There are some very valuable pieces of information that you have omitted
from your description of this application, namely size of the area and time
to do the application. You have already noted that there are some pits, but
in what condition is the remainder of the concrete? Your prep work may
involve the use of degreasers or other cleaners to remove contaminants. An
abrasive blasting procedure may also be required to remove laitance that
would lead to delamination of the applied coating system. As you can see,
there is no simple, fast cure answer.
With regard to your question on a fast cure material for filling the pits,
agrigate filled epoxy systems have been used quite successfully for this
purpose. Many of these are low viscosity systems in the neat form that
penetrate into the substrate. The agrigate would then be used in the
"filler coarse" of the system. Typically, polyurea spray system can be
applied over these within a matter of hours.
Another very viable method would be to use a slow cure polyurea joint sealant type system to fill the pit areas. This procedure has also been
used quite successfully and is being used today. Agrigate can be introduced, depending on the depth of the pit.
The whole surface area would need to be prepped and then primed with a good
penetrating primer system. The pit areas could then be filled, allowed to
cure and then coat with the polyurea system. I would suggest that you keep
all traffic, or as much as possible, off the prepared substrate before
completing the project. Small "spot repair prep work" may be required
before final application of the polyurea system.
Another material would be the fast set cementicious materials. Caution
must be used here as thin films of these do not "cure" properly and leave a
very friable / dusty substrate. This would lead to disbonding of the
coating system.
The best advice would be to refer to the polyurea system supplier for
guidance on compatible filler materials to their polyurea system being used.
3.
Question: I manage the coatings area of the materials technology section of
Transport SA, our Department of Transportation. We have begun looking at
polyurea as a pavement marking material, in association with a manufacturer
here in Australia, but were wondering if the PDA can put us in contact with
any manufacturers or contractors who may be using this material as pavement
marking in the USA. Your people may have had considerable experience with
this material, and may be able to indicate how successful this material has
been in this application. Any assistance would be appreciated.
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Answer:3M has been working on the use of a polyurea/polyurethane hybrid system for
road marking applications.
Specialty Products, Inc. (PDA Member, Washington state) has been supplying
polyurea systems to an applicator that is doing some striping work at the
Newark Airport in New Jersey.
Visuron Technologies (PDA Member, Michigan state) has been supplying
polyurea road marking coating systems for a variety of application areas.
Some information is available on their web site.
IPS (JV company between Mark Rite Lines and Reichhold) had supplied some
polyurea systems to road marking work. I am not sure of the status of that
work.3M has been working on the use of a polyurea/polyurethane hybrid system for
road marking applications.
Specialty Products, Inc. (PDA Member, Washington state) has been supplying
polyurea systems to an applicator that is doing some striping work at the
Newark Airport in New Jersey.
Visuron Technologies (PDA Member, Michigan state) has been supplying
polyurea road marking coating systems for a variety of application areas.
Some information is available on their web site.
IPS (JV company between Mark Rite Lines and Reichhold) had supplied some
polyurea systems to road marking work. I am not sure of the status of that
work.
4.
Question: What standard applies to lining of gasoline tanks (metal)?
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Answer:We at the Polyurea Development Association have not yet developed specific
standards relating to the use of the polyurea technology for lining gasoline
tanks, or any other specific application area.
There are a couple of standards prepared by NACE (National Association of
Corrosion Engineers) and SSPC (The Society for Protective Coatings) that
relate to lining of steel tanks for immersion service by various coating
systems. There are also standards relating to the required surface
preparation before the lining work. The API (American Petroleum Institute)
will also have some guidelines with respect to lining applications.
NACE RP0178-95: "Fabrication Details, Surface Finish Requirements, and
Proper Design Considerations for Tanks and Vessels to be Lined for Immersion
Service"
NACE TPC2 Publication: "Coatings and Linings for Immersion Service"
You must also refer to the Surface Preparation standard used to prepare the
metal surface before application of the lining system. These will be
recommended by the polyurea system supplier and are noted as follows:
NACE No.1 / SSPC-SP5: White Metal Blast Cleaning
NACE No.2 / SSPC-SP-10: Near-White Metal Blast Cleaning
NACE No.3 / SSPC-SP-6: Commercial Blast Cleaning
NACE No.8 / SSPC-SP-14: Industrial Blast Cleaning
Before undertaking this application, I would insure that the polyurea system
to be used will handle immersion in gasoline. You must also not the affect
of the additive package used, whether alcohol or MBTE, as these may have an
affect on the polyurea system. This immersion data will be available from
the specific supplier of the polyurea elastomer system. You may also have
to decontaminate the steel surface should the vessel have been used to store
gasoline before and no lining system was used.
5.
Question: I have a new project opportunity which requires potable water approvals.
Has PDA ever sent "generic" polyurea coatings for this testing and
approval?
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Answer:A polyurea system which may have the ANSI/NSF-61 has complied with certain criteria required by that testing protocol, however, it is important to review the proposed installation configuration to know whether the "approved system" has met the particular aspects of the ANSI/NSF-61 protocol which is relevant to that proposed use. There may be subdivisions of use within an "approved" category and unless a system meets the requirements for a particular subdivision it may still be inappropriate for that particular use. It is recommended that contact with the supplier of the system be made and full analysis of the intended use covered with that company.
The ANSI/NSF-61 testing does not cover physical properties of the system such as elongation, tensil or chemical resistance. There may be a general relationship between the qualities in a system necessary for becoming approved and those physical properties, but again the proper procedure would be to contact the vendor about their particular system and the proposed use.
As per UL's ANSI/NSF-61 approval, the published companies on their web site and product is as follows:
Semstone 403 from Plasite
EnviroLastic AR 520PW from General Polymers.
6.
Question: We are looking for a polyurea to use in sulfuric acid aplications and for hidrocabures.
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Answer:The polyurea technology in general has good resistance to low concentrations of sulfuric acid at normal operating temperatures. In concentration of less than 10%, at relative ambient conditions, polyurea systems perform well. If that concentration is exceeded, or if the exposure temperature is increased, breakdown of the polymer can and will occur.
The same holds true for hydrocarbon exposure. Certain low molecular weight hydrocarbons may tend to penetrate the polymer and are absorbed causing swelling and softening. This is a characteristic of the polymer backbone of the various formulations.
Much of the chemical resistance of the polyurea technology is significantly dependant on the specific polyurea formulations used. There are some that have better acid resistance than others while certain formulations offer better hydrocarbon resistance.
7.
Question: I have come across polyurea through one of the recent patent publication, where
polyurea is used as a passivation layer. We are a company developing inkjet printheads. I am looking for a passivation layer which is water resistant and chemically resistant to printing inks. Could you please help me in answering the following questions. 1. Is polyurea can be deposited by vacuum deposition to achieve a thin layer of the order of 3 to 10 micron. 2. What other methods can be used for deposition ? 3. Could you please supply the materials safety data sheet.
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Answer:There are many versions of the "polyurea" technology as with "polyurethane" technology. While the PDA is mainly focused on the plural component type materials that are "field" applied at this time, your question opens the door to an new age of the technology. The term "polyurea" is a descriptive one that identifies the type of organic linkages found in the polymer backbone. There are numerous possibilities of how that linkage is formed, or put together if you will. There are numerous references to a variety of "polyurea" polymers that are also used in medical applications. The "polyurea" technology in general is very resistant to water and common
printing inks, though the printing inks may stain the polyurea depending on the complete polymer backbone.
The "polyurea" you have come across in the patent search is produced in an aqueous type media such that spheres / balloons of the polyurea polymer encapsulate the ink material. This can then be deposited to various substrates such as that found in carbonless carbon copy paper. When
pressure is applied in localized areas, the spheres burst and release the ink to make a "mark". This that is described is oversimplified of course of the actual procedure.
"Polyurea's" can be deposited by vacuum though we don't feel that any of the current members of the PDA have any experience in this area. Most of the application techniques we see are those where the "polyurea" system is applied via plural component technique. The 2-components that form the polyurea polymer are mixed in either a high pressure, high temperature impingement mix spray gun and applied to surfaces at film thickness of 0.38 mm or greater or by using a low pressure pour / static mix technique for joint sealant applications.
For the application you speak of, the "polyurea" would need to be formed in a solution / suspension and deposited on the substrate. That solution / carrier media would then dry / evaporate and the polyurea polymer film formed.
As far as the MSDS is concerned, there are many specific MSDS's relating to individual companies 2-components of the polyurea system. We are not aware of any MSDS on "polyurea".
8.
Question: When replacing a used drum of iso I noticed the amount left in the bottom had flakes of hardened iso floating in the remaining product. Is this moisture contamination? Product is hybrid mix, only vented to air when transfer pump is operating, we have
had no problems with product when applying.
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Answer:I would guess that the hardened iso you see is indeed a result of moisture contamination. If you are leaving one of the bung access ports open while transferring materials there would be a natural flow of ambient air into the drum as the product levels drop.
Depending on where you are located and the atmospheric conditions there could be plenty enough moisture being drawn in under these circumstances to cause reactions and crystallization on the surface of the product.
You mention that this is a hybrid system. Depending on the particular iso formulation a hybrid system might even be more sensitive to moisture contamination than some of the purer systems, however most iso compounds are reactive with moisture.
Do you have an air dryer installed in the small bung hole on the drum? If not, you most definitely need one of those. I believe most product manufacturers would recommend use of a dessicant air canister on the iso drum. These devices are mounted on a 3/4" pipe which can be screwed right into the small bung on most drums and once attached will absorb ambient moisture from air inflowing to the drum. It will be difficult to remove 100% of the moisture but it can be significantly reduced using these devices.
You should try to overcome this problem because eventually enough crystallization might occur to plug one or more lines, the pump or your gun, and cause plugging in the filter screens and heater areas.
9.
Question: At the conference in Orlando, Greg Livingston spoke about the need to have an "application checklist" to ensure the proper and safe application of Polyurea ata a customer site. I am only starting in Polyurea and I want to make sure that I make no mistakes from the outset. Can I get a standard draft of the basic questions i need for my checklist? Is there one already developed? Or can I get it from some place else?
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Answer:This question is quite broad. There are a number of issues which need to be addressed in "staging" a polyurea installation for a customer. Obviously the safety issues should be immediately considered as they pertain to both the installation personnel as well as the overall job site safety. These "checklist" items are generally what Greg lectured on at the PDA meeting.
Each individual vendor of systems may have their own specific "checklist" of job related questions to be considered in preparing for a job. I would advise the questioner to survey whichever vendors he may wish and ask for job related specifications and staging criteria. I expect that most of the leading vendors have given some thought to the type of issues related to different applications and may have even reduced the issues to a "checklist" type of format.
As soon as the technical committee can do so, it would be good to have a PDA reference on the topic of safety in installation of polyurea systems. At the moment there is probably some good reference material available through SSPC or Society of the Plastics Industry regarding spray applications of Isocyanate based products.
10.
Question: I am purchasing manager for construction company from Belarus. At this point we have a project of water park development in our country. We would like to use polyurea as a decorative coating in our pools. If it makes sense, please advise product type, coverage and recommended thickness of the coat.
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Answer:The proper polyurea coating system would be a good choice for use in a water park application.
As with most potential applications there are a number of particulars about the proposed installation and use that must be reviewed prior to making any specific recommendations. Further, it should be incumbent on the questioner to direct his specific questions to a vendor of systems. I would think that PDA might be in a position to provide a list of member systems vendors to the questioner and he could then direct his questions as he so chooses. Polyurea systems have been used for this application area. The specific supplier would recommend system and application requirements.
11.
Question: In the FAQs section on the PDA site, one of the answers claimed that a company has an "approved coating system". Can you tell me which company and how I can find out more about their certification? Is it only a reference to their system being safe for potable water or even about the adhesion, elongation and chemical resistance?
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Answer:A polyurea system which may have the ANSI/NSF-61 has complied with certain criteria required by that testing protocol, however, it is important to review the proposed installation configuration to know whether the "approved system" has met the particular aspects of the ANSI/NSF-61 protocol which is relevant to that proposed use. There may be subdivisions of use within an "approved" category and unless a system meets the requirements for a particular subdivision it may still be inappropriate for that particular use. It is recommended that contact with the supplier of the system be made and full analysis of the intended use covered with that company.
The ANSI/NSF-61 testing does not cover physical properties of the system such as elongation, tensil or chemical resistance. There may be a general relationship between the qualities in a system necessary for becoming approved and those physical properties, but again the proper procedure would be to contact the vendor about their particular system and the proposed use.
As per UL's ANSI/NSF-61 approval, the published companies on their web site and product is as follows:
Semstone 403 from Plasite
EnviroLastic AR 520PW from General Polymers.
Answer:Its the period of time during which another coat of product may be applied to previous coats of product and still obtain good adhesion/results......a window of time. Different products have different periods during which acceptance of additional coats will be optimized.
13.
Question: I have read many articles about the waterproofing capabilities of polyurea. I am building a new home and want to know if it would be a proper application over plywood for the front and rear porch decks. My concern is the movement of the wood. If this is a proper application, what is the proper preperation?
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Answer:Polyurea membrane systems are indeed excellent waterproofing materials. They can be applied over wood surfaces using the proper steps. Typically wood, especially plywood or OSB, has significant moisture content and general porosity that make the use of systems producing heat upon cure problematic. Usually to successfully coat a wood surface with the typical sprayed polyurea system it is necessary to apply a good primer that will effectively seal the surface against moisture/vapor emission.
There are a several polyurea based systems that might be considered for this type of application depending on the objectives for appearance and the budgets for application. There is a fairly wide range of costs for the different types of systems.
The inquirer should contact product manufacturers listed on the PDA membership list to get specific recommendations for his project.
