Friday, April 2, 2021

Choosing a Spray Gun Based on Your Project Needs

by on April 02, 2021

A vital part of Polyurea application is choosing the right gun. Within this article, we will review the top seven types of Polyurea and Polyurethane applications, which gun is best, and why you should choose them for your next project.

The technologies in the spray guns we will be discussing combine rapid trigger response, superior atomization, and quick-change spray pattern size to output combination allowing for longer duration for spraying.


Roof & Wall Insulation

Practically any spray gun will work great for roofing and wall insulation. The Graco Fusion line is a popular choice, along with the PMC Air Purge line. Click here for more options.

Graco Fusion Mechanical Purge Spray Gun




Air Sealing Attics and Rim Joists

Applying open-cell foam or closed-cell foam in attics and walls, having a durable gun that is lightweight and simple to handle is crucial. The Fusion CS and Fusion, Mechanical Purge guns are ideal for sealing wear tight rim joists. Click here to learn more about these guns.




Roof Coatings

Given the variety of roof coatings needing multiple materials applied, including a closed-cell foam and coatings – the Fusion Mechanical Purge, GX-7, and Problem P2 are all ideal for high output spray polyurea applications. Learn more about our roofing system guns.




Pipe & Tank Coating

For projects requiring protection of storage vessels, including; steel and concrete tanks, pipe linings, reactors, rail tank cars, truck tankers, potable water tanks, bulk dry-storage tanks, and more – the best-fitted guns are Graco’s Fusion Air Purge, Fusion Mechanical Purge, and GX-7. Alternatively, PMC’s AP-3 and PX-7 Mechanical Pour Gun are ideal as well. Learn what to use for Pipe & Tank Coatings.




Secondary Containment Spill Prevention

A secondary containment system provides an essential line of defense in the event of a failure of the primary containment, such as a bulk storage container, a mobile or portable container, piping, or oil-filled equipment. Graco Fusion Air Purge and Mechanical Purge and PMC AP3 or PX-7 Mechanical Purge are ideal for these types of projects. Click here for more options.



Spray-On Bedliners

When applying the material to truck beds, a variety of entry-level and industrial-use equipment are available—starting with Graco Fusion Air Purge, Fusion Mechanical Purge, GX-7 – as well as PMC’s AP3 and PX-7 Mechanical Purge. Learn more about these guns.





Waterproofing

When working on waterproofing projects, efficiency is key. Graco Fusion Air Purge, Mechanical Purge, and GX7 and PMC’s AP3 and PX-7 Mechanical Purge work exceptionally well for waterproofing projects. Learn more about these guns.





Types of Spray Guns



Air Purge Spray Guns

The Graco and PMC AP series spray guns present the operator with easy-to-operate and maintain spray guns that can be utilized in various applications. These air purge guns provide the operator with simple output settings by simply removing and replacing the appropriate size chamber right from the front of the gun with no gun disassembly needed.

The design of these guns enables the applicator to leave the gun connected to the hose set at the end of the day by pumping a small amount of grease into the mixing section.

Some of these gun’s features combine a revolutionary 360-degree rotational head allowing hoses to be connected to the top or the bottom of the gun. This quick-change mixing chamber allows removal from the front of the gun without disassembling two separate air connection locations: one-piece machined mixing chambers and a new air cap designed to preserve the mixing chamber tip.

Mechanical Purge Spray Guns




Graco Mechanical Purge Spray Gun provides the applicator a spray gun designed to reduce operator fatigue and facilitate utilization control. With this aim, a new ergonomic gun handle has been produced and placed at the center of balance to balance weight distribution and provide enhanced stability during the application.

All models include a tool kit with the necessary tools for proper adjustment and support of the gun. Some of this gun’s features combine superior mixing, while the engineering cleaning minimizes reacted substance inside the mixing chamber. Easy spray pattern tip turns out without changing the mixing chamber and a powerful air cylinder to expedite the rapid valving reaction.





Graco Fusion Spray Gun

The Graco Fusion Spray Gun features an easy air-blast tip cleaning to help reduce build-up and tip clogging. The spray gun’s long-lasting side seals mean less downtime for maintenance, and applicators experience quick-release fluid housing, allowing you to change the mixing chambers without simply using tools.

If you need to remove the front cap, it can be quickly removed or replaced by the hand-tightened front cap – no tools are required to clean the spray gun, maintaining the seal and mix chamber.



Capabilities

  • Maximum Fluid Working Pressure – 3,500 psi
  • Minimum Air Inlet Pressure – 80 psi
  • Maximum Air Inlet Pressure – 130 psi
  • Maximum Fluid Temperature – 200˚F
  • Air Inlet Size – 1/4 npt Quick Disconnect Nipple
  • A Component (ISO) Inlet Size – -5 JIC; 1/2-20 UNF’
  • B Component (Resin) Inlet Size – -6 JIC; 9/16-18 UNF
  • Sound Pressure – 81.1 dB(A), using AR5252 at 100 psi (0.7 MPa, 7 bar)
  • Sound Power, measured per ISO 9416-2 – 91.0 dB(A), using AR5252 at 100 psi (0.7 MPa, 7 bar)
  • Dimensions – 7.5 x 8.1 x 3.3 in
  • Weight – 2.5 lbs
  • Wetted Parts – Aluminum, stainless steel, carbon steel, carbide, chemically resistant o-rings

Friday, March 19, 2021

Polyurea spray coatings can protect anything

by on March 19, 2021




Polyurea spray coatings can add some amazingly strong properties to otherwise fragile structures in a matter of minutes. If you've never seen it, a video search can show loose stacks of cinder block, Styrofoam coolers, and even watermelons made indestructible after simply "painting" them with this stuff.

Polyurea is a long-chain elastomer of isocyanates and amines that form urea substances at their converging joints.

... which is a detail you'd be hard-pressed to even find a use for in a profession playing trivia video games at your local pizza store. The fundamental part here is that there are long molecular chains of strong bonds that link together with a compound called "urea". There are many of these links, hence the "poly" part of the name. One benefit of these chains of particles being long and complex is that they hold firm and take in a lot of energy and can reorient in between the interlinking bonds to extend.

This makes the material suddenly strong and flexible at the same time. While particular polyurea solutions might differ, they are quickly lot of times stronger and often times more versatile than epoxy. These substances achieve around 6000 psi tensile strength and 500% -800% elongation prior to breaking, with particular blends accomplishing over 250,000 psi strength! By comparison, moderate steel has a tensile strength of simply 50,000-65,000 psi. And all of this from a spray finishing!

How is this useful?


Think of it. You can essentially spray a flexible, waterproof coating with the strength of steel onto any shape. There are no VOCs. It sets to the touch in just seconds and cures to full strength within hours. Some just recently established polyurea-based materials are even self-healing at space temperature-- and this on a molecular level, which indicates it can recover itself over and over once again in the very same location.

The military definitely took notice. These compounds have actually been utilized in military cars and structures to improve armor and minimize shrapnel from roadside (or undersea) bombs without including significant weight. This is something the Army, Navy, even the Pentagon has actually taken advantage of.


Commercially, polyureas are utilized to seal and protect building roofing systems offering long maintenance-free performance.

Perhaps among the most popular and familiar uses is for spray-on bed liners. Under the popular brand "ArmorThane", polyurea coatings are applied to an entire array of automobile and rv parts.




Boat hulls are coated below the waterline for protection from abrasion and deterioration. Polyurea coatings here last about 8x longer than conventional coatings in these extreme marine environments.

These substances are formulated by significant chemicals or coatings companies like 3M and BASF. Specific formulas will differ in strength and flexibility and can be colored as desired. Some are even approved by FDA/ USDA for food contact.

Consider where polyurea coatings may bring the level of performance you require to your items.

Monday, December 28, 2020

Polyurea Vs Polyurethane: What Are The Differences?

by on December 28, 2020

 


Two-component polyurea elastomeric coating systems make up the cutting edge protective coating industry. While they both might have some common characteristics, polyurea systems are a unique innovation in itself. Two-component polyurea systems are typically understood for a really fast dry time (normally less than 30 seconds), attained without utilizing a catalyst as in the two-component polyurethane systems. This rapid dry time is extremely consistent over a very broad ambient temperature variety. While the fast reaction/ rapid dry time is practically unaffected by ambient wetness, the presence of moisture on a substrate must be considered when achieving adhesion to that substrate. 


This is all made possible by the distinct chemistry of basic materials used to develop the two-component polyurea systems. Two-component fast set polyurea systems usually do not include any solvent or Volatile Organic Compounds (VOC). They are generally processed by specialized plural part equipment, which establishes high pressure and high spray application temperature level. The two parts are combined inside the impingement mix spray weapon, as there usually is not any pre-mixing or hot potting. Because of the introduction of the two-component polyurea technology, a wide range of applications are seen. These include coating/lining applications over concrete, geotextile membranes, various metals for corrosion, ornamental areas, and some plastics. For all of these, the fast dry time of the technology indicates that the application area can be gone back to service rather rapidly. Polyurea systems with a slower/ customized reactivity and set time are likewise discovering use in joint sealant/filler system applications. Here the product is integrated in a low pressure, low temperature by means of "folding" in a static mix tube and applied as a bead of material.

Recently the Polyurea Development Association prepared and released a definition of polyurea systems. That is identified as follows: "A polyurea coating/ elastomer is that stemmed from the reaction product of an isocyanate element and a resin blend element. The isocyanate can be aromatic or aliphatic in nature. It can be monomer, polymer, or any alternative response of isocyanates, quasi prepolymer or a prepolymer. The prepolymer, or quasi-prepolymer, can be made from an amine-terminated polymer resin, or a hydroxyl-terminated polymer resin. The resin mix must be made up of amine-terminated polymer resins, and/or amine-terminated chain extenders. The amine-terminated polymer resins will not have any intentional hydroxyl moieties. Any hydroxyls are the result of incomplete conversion to the amine-terminated polymer resins. The resin mix might likewise consist of additives or nonprimary parts. These additives may contain hydroxyls, such as pre-dispersed pigments in a polyol carrier. Generally, the resin mix will not contain a catalyst(s).


Well, that is a mouthful and what does it all mean? This article will attempt to provide a basic summary of the innovation and is not meant to be a complete chemistry innovation lesson on polyureas, hybrids, and polyurethane systems.





A BRIEF HISTORY of POLYUREA DEVELOPMENT:.

The very first actual referral to polyurea can be found in 1948 when some scientists were examining thermal properties/ melting points of various polymer systems. They were comparing polyesters, direct polyethylene, polyurethanes,  polyamides, and polyureasand, discovered that the polyureas had far exceptional thermal properties and an extremely high melting point. Remember that these polymers were manufactured in a laboratory environment and were not very conducive to coating/ lining applications. Visual representation of the melting points of different polymers for contrast.


The advantages or special characteristics of polyurea over polyurethane and
polyurethane/polyurea hybrid system in RIM applications consisted of rapid molding/ treatment time which was generally 2-3 seconds set or gel times with a dry time of less than 10 seconds. Also understood was decreased part scrap rate and most notably, the capability to paint the parts using the online Electrophoritic Paint Deposition (ELPO) procedure. 

This process included warming the parts to almost 400 ° F( 205 ° C ), a temperature level that was really. harmful to a polyurethane and most hybrid systems. Polyurea systems are kept in mind for their high thermal stability.
The two-component fast set polyurea coating/ lining innovation was first presented to the market in 1988, following the advancement in 1986.4,5 This technology progressed from the requirement to establish a more steady, durable and 100% solids polymer system for coating rigid, spray used polyurethane foam utilized in roofing and other insulation applications. 

Some of the very first plural part spray used polyurea formulations had.
get times of 1-- 2 secs, with tack without < 10 secs. The actual very first commercial application of the polyurea elastomeric coating/ lining technology was as a roof system in 1989.
Nevertheless, this was not the first real work with the spray applied two-component polyurea innovation. Earlier work in the 1970's made use of modified polyamines and high levels of plasticizers and solvents to attain a sprayable system for coating work. While this proved successful in laboratory applications, poor field performance was kept in mind and this innovation never ever got acceptance. A distinct, solvent polyurea/ epoxy/ urethane hybrid type system was also utilized in the 1970's for the production of a composite traction system. Other uses included short-lived shelters, roof, and blast defense. This was not a true polyurea system though.

In 1998, the National Association of Corrosion Engineers (NACE) issued a Technical Report on polyurea systems in an effort to provide a preliminary description/ contrast of polyureas to polyurethanes. This document gives a really basic view of technology with limited basic details as to the chemistry included.


POLYUREA CHEMISTRY/ FORMULATION:
Since we, the Polyurea Development Association, are focusing our efforts on defining the technology, we require to identify what part of the technology/ response we are looking to that categorizes whether a polyurea or not. The agreement seems to be that we are looking at a 2-part processed system, whether it was spray, caulk, put or RIM processed.
Therefore, the determining reaction would be the response that occurs between the 2-the part system, i.e. the response of the polyisocyanate component and the resin blend element. This would be the polymerization/ curing part. 

This is a thermoset response
The primary identifying characteristic with the polyurea innovation over polyurethanes is that amine-terminated (- NH2) resins are used rather than hydroxyl ended (- OH) resins, typically described as polyols. The reaction of the amine ended resins with the isocyanate element leads to the development of a urea linkage. Considering that this is a polymer and these units repeat, the term polyurea then applies. A basic illustration of the "polyurea" response is offered below (Figure 3), compared to polyurethane in Figure 4:.


Figure 3: Polyurea Development Reaction.
Figure 4: Polyurethane Formation Response.

It should be kept in mind that "polyurea" is a description of a technology and it in itself is not a coating system. There are a range of solution possibilities to achieve the desired performance, as well as numerous ingredients that might be used. This is enabled by the selection of various basic materials in the formula, much like that for polyurethane chemistry. The choice of appropriate basic materials for the system can be very intricate procedure.
Based upon reactive equivalents between the polyisocyanate part and the resin mix part for the 2-part systems, the following Table I can be established.

From Table II, one can see that for the resin blend part of the 2-part fast set polyurea elastomer systems, the chain extender contributes the most part of the reactive hydrogen equivalents with the isocyanate-reactive equivalents. The chain extender is actually the identifying aspects of what makes a polyurea. There are no polyols, or hydroxyl ended materials, utilized as the main reactive resin in the resin mix part of a two-component polyurea elastomer system. If so, then these would be classified as a polyurea/polyurethane hybrid system.
One might then likewise point to the response of wetness with the polyisocyanate part When wetness enters into the reaction mechanism, the wetness would react with the isocyanate to form a carbamate. This will extremely rapidly dissociate into an amine-terminated molecule, which would then extremely quickly react with an isocyanate speciemoiety to form a urea linkage. For this reason, forth, single component wetness treated urethane.
the system could be thought about as a polyurea system, however not a two-part system. The wetness of the response is the treating mechanism to the response.
There is also some interest and operate in the 2-part systems where part of one element is obstructed, both parts are mixed and reaction/ curing occurs when another element is presented. This other aspect might be heated, as is the case of blocking the isocyanate element (using oximes and phenols). The other would be wetness, as when it comes to obstructed amine resin blends (development of aldimines).


Aromatic Based Polyurea:.
Fragrant based two-component polyurea systems have actually been the workhorse of the two-component polyurea innovation. Aromatic refers to the nature of the chemical backbone of the polymer system. The two-component systems consist of an isocyanate part and a resin mix component. The isocyanate component is usually an isocyanate quasi prepolymer, prepared from methylene diisocyanate.

These are not the only two kinds of chain extenders that might or are currently used; there.
are others that can supply the very same impact. A lot of these are solids at room temperature level.
and might be difficult to mix into the resin blend portion by the maker of the system.
Table IV reveals the relative response rates of an isocyanate component with different amine-terminated materials. The secondary or hindered diamines extend the reactivity of the rapid dry two-component aromatic polyurea elastomer innovation to enable improved processing and much better substrate wetout/ adhesion.



Aliphatic Based Polyurea:.
Following the intro of the fragrant based two-component polyurea elastomer.
systems; the fast dry aliphatic-based products were established.9,10 For these systems, you.
also have an isocyanate element and a resin mix portion. The isocyanate is likewise a.
quasi-prepolymer, like with the fragrant based two-component polyurea systems.
Nevertheless, the isocyanate utilized is a light stable monomer and the "polyol" might in fact be.
the polyoxypropylene diamine. The typical isocyanate used is isophorone diisocyanate.


EFFICIENCY ISSUES:.
In general, the standard fast set polyurea spray innovation is comparable to physical properties of polyurethane/polyurea hybrids and polyurethane systems. Simply put these innovations of coatings/ lining systems can be created to accomplish a range of elastomer physical properties.
The genuinely big benefit of polyurea technology is the speed of response and the capability to put the structure or center back into service very quickly. One has to be really careful here though due to the fact that polyurea systems may set and give a preliminary treatment really rapidly that will permit this "go back to service" very rapidly, but not establish supreme elastomer physical properties for 24 hours or more. This all depends upon the specific polyurea system formulation.
The polyurea systems do tend to have much better flexibility at lower temperature levels than to the corresponding polyurethane/polyurea hybrid or polyurethane system. 
The innovation also carries out effectively with regard to thermal shock resistance.

Moisture and Temperature Sensitivity:.
One of the significant benefits of the polyurea innovation is the relative insensitivity to wetness throughout processing/ application. As the amine-- isocyanate reaction tends to be preferential over the hydroxyl-- isocyanate reaction, foaming of polyurea systems is nearly impossible. However, it can happen, especially if a driver is present. For polyurethane/polyurea hybrids and polyurethane systems, catalysts are utilized to control the reaction. If wetness is present, they may exhibit  some foaming which leads to decrease density, porosity and poor performance.

Effect of Moisture on Elastomer Density.
Figure 14 shows the impact of wetness/ humidity during processing of both a fast set spray polyurea and spray polyurethane systems. As the INDEX boosts, ratio of isocyanate equivalents to reactive hydrogen equivalents, the density of a  polyurea system remains consistent while the polyurethane system shows a decline in elastomer density.
The non-polyurea system foamed due to the catalyzed response of isocyanate with the moisture in the air. This reduction of density/ foaming would result in total efficiency concerns for the polyurethane system. Comparable outcomes have likewise been shown with a polyurethane/ polyurea hybrid technology.

While polyurea systems might show insensitivity to moisture, that does not suggest they can be applied over a wet substrate. The polyurea will react over the water, but the used system will not bond to the substrate because area.
The ambient temperature and substrate temperature level might have little affect on the response and treatment of a polyurea system as compared to the  others. But, the real important concern is substrate temperature level and dew point. Market basic coating practices need to likewise be.
followed with polyurea systems and application because the substrate temperature level must be 5 ° above humidity and increasing. If not, moisture will condense on that substrate and cause adhesion concerns with the polyurea innovation, similar to other coating/ lining systems.

Chemical Resistance:
Polyurea systems in general show comparable chemical resistance properties as that of similar formulated polyurethane/ polyurea hybrids and polyurethanes. This is due mainly to the reality that all have the polyether backbone in the elastomer. The urea linkage discovered in the polyurea along with the hybrid system is more resistant to hydrolysis.
than the urethane linkage. Polyurea systems do tend to have much better resistance to alkali high pH, than the hybrids or polyurethane systems. Aromatic polyurea systems are subject to chemical oxidation.
There are some more recent innovations of polyurea systems that are showing considerably higher chemical resistance with respect to extremely acidic environments. Remember that chemical resistance/ efficiency can be straight related to processing conditions of the polyurea systems. Those that do not attain total mix and include porosity will have lower chemical resistance performance than those processed at the optimum conditions. This would consist of appropriate processing temperatures and pressures as well as.
the correct mix setup in the spray gun. 

Thermal Analysis of Two-Component Rapid Dry Polyureas:.
One extremely interesting note about the rapid dry two-component aromatic and aliphatic polyurea elastomer systems is the resultant thermal properties of the polymer films.
Two-Component polyurea elastomer systems are amorphous in nature, not crystalline like polyurethane systems. This amorphous nature is similar to that of epoxy type systems other than that two-component polyurea system do not have a real glass transition temperature level. Rather, 2 unique Tg's can be noted, one corresponding to the melting point of the soft-block in the polymer and the other corresponding to the melting point of the hard-block in the polymer.
From Dynamic Mechanical Spectroscopy examinations of typical two-component polyurea elastomer systems, a low temperature Tg is noted at about -50 ° to -60 ° C with a high. temperature Tg of about 230 ° to 260 ° C for the fragrant based systems. The twocomponent aliphatic polyurea systems have a low temperature level Tg about the like the " Polyurea Coatings:
two-component fragrant polyurea however have a heat Tg of about 110 ° to. 120 ° C. 10 The response curve between these 2 points remains relatively flat. This would be the efficiency variety, temperature smart, for a polyurea elastomer system. In lay terms, the polyurea elastomer systems would tend to show some substantial stiffening at temperature levels less than -50 ° C with some polymer softening, or possible decomposition,.
at the upper temperatures Tg's Figure 15: Dynamic Mechanical Spectroscopy of Aromatic Polyurea Spray. 
Shrinking During Cure:.
Because the formation of the elastomeric polyureas is based upon a thermoset response, some direct shrinkage during remedy will take place. This is not thermal growth/ contraction due to temperature level modifications. The total quantity of shrinkage will depend upon the reactive constituents of the isocyanate and resin mix components, even though the elastomeric system might have elongation values greater than 200%. These direct shrinking forces might be strong enough to curl the corners or edges of the used work and might cause disbondment or damage to the substrate. The elastomeric polyurea systems utilized must be developed for the particular coating/ lining application work. 

Weatherability Properties:
Aliphatic polyurea systems have outstanding resistance to degradation by ultraviolet light and are utilized for a variety of exterior and interior atmospheric services.
The Aromatic polyurea systems have great resistance to ultraviolet light from a total performance standpoint. Even with using UV Stabilizers/ Antioxidants, they will however end up being blemished and fade with time when utilized in light colors for exterior exposure.
environments.

CONCLUSION:.
Two-component polyurea elastomeric coating/ lining systems may be rather of a newcomer to the market, however it has revealed a good deal of versatility and application usage.
The quick dry time attributes offers an exceptionally excellent cost and time-effective option to a variety of coating/ lining applications over traditional technologies. With the severe efforts for commercial rehab and increasing requirement to abide by ecological, economic and time restrictions, the speed and sturdiness of the twocomponent polyurea technology hold fantastic guarantee.
As using this innovation grows, so does the confusion regarding what is a polyurea and what is not. Hopefully this text will have offered the reader a better understanding of what a polyurea systems is as compared to similar technologies of polyurethane/ polyurea hybrids and polyurethane systems.
The two-component polyurea technology must be dealt with as other coating type systems with regard to correct and total surface area preparation. The originality of the technology is not a cause to restrict and even remove proper, industry accepted surface preparation standards. The substrates should be clean, dry and free of contaminants.
Continuous advancement of new raw materials for solution work will move this technology to a higher level of industrial coating/ lining work while preserving the individuality of the polyurea technology.


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