活動

  • Peters Wind 的簡介照片

    Peters Wind 發表更新 8 年, 1 月前

    The coverings industry has come a long way from brushes and containers. Over the past 30 years, chemical engineers have formulated innovative polymer resins that have a variety of modulus (from high to low), much better fire retardancy, low VOCs and faster response times. Today’s contemporary finishings, consisting of polyurethane and polyurea, are among the most advanced resins established. These polyureas, more than other polymer coating, stand apart in their flexibility, strength and longevity. They are the next step in the finishes advancement.

    Together, advances in finishes technology have also caused the advancement of spray, injection and roto-cast application devices that also enhances the performance of polyureas. In particular, plural element devices technology has actually been improved to make spray application easier, more consistent in protection, suitable at lower pressures (as low as 1,000 psi) and generating less overspray or fogging.

    Polyurea materials have 2 parts: the isocyanates quasi-prepolymer and a resin blend. The resin mix is a combination of amine-terminated chain extenders. Unlike polyurethanes, no polyols are used in the manufacture of polyurea resins. When the products are mixed together in the application equipment, the isocyanates and the amine resins react to form a urea linkage (see Figure).

    Introduced in 1989 by the Texaco Chemical Co., polyurea was concerned by lots of in the coatings industry as an "over-hyped" product with overstated features and advantages. Real, polyurea systems and technology have numerous outstanding homes. Nevertheless, many producers of conventional finish product marked down the claims of polyurea being the " marvel" item; as a result, lots of producers and end users lost sight of the true advantages of the product.

    Swift Reaction Time

    Figure 1Polyurea’s speedy reaction time (5-15 seconds) leaves polyurethane and epoxy products in the proverbial dust. It is an autocatalytic polymer. With the swift reaction time, polyureas do not easily respond with humidity and moisture in substrates, so the product can be easily applied over cold or wet substrates, such as steel, concrete, wood or PU foam. On the other hand, when smoother flow of material is needed to damp out a mold or cover an elaborate carved surface, polyureas (like polyurethanes) can be slowed down to have gel times ranging from 20-60 seconds.

    Immediate response time is a excellent advantage of polyurea. In the case of center upkeep or renewal, owners want to gain back use of the facility as soon as possible. A fast-reacting polyurea totally remedies within a couple of hours, whereas the majority of polyurethane or epoxy coatings require 24-48 hours prior to the covered areas can be used to their complete potential.

    Polyurea is regularly used to safeguard the exterior of iron pipe, considering that the pipe can be recoated "above-the-ditch" (in the field) without expensive equipment. The polyurea treatments rapidly and the pipeline can be practically immediately reburied without fracture. Lots of pipelines around the world, consisting of the Trans-Alaska pipeline, have utilized this technology to speed production and keep maintenance expenses to a minimum.

    Wetness Insensitivity

    Precisely where moisture or humidity is a issue, polyureas exceed any product on the marketplace today. Polyurethanes can be conscious high humidity and moisture in a substrate. As
    bedliner , they will respond with atmospheric moisture or high humidity to produce carbon dioxide gas and cause foaming and/or pinholing in the surface area. In contrast, polyureas are not affected by moisture.

    The response of Component A and Component B (polyamines) or a polyurea system is so quickly that the moisture response can’t happen. For that reason, the polyurea systems are not conscious moisture and humidity, and do not normally produce co2 bubbles. This is an benefit in climates or regions with high humidity or dewpoints.

    Excellent Adhesion

    If a substrate is damp or has condensation on it, polyurea will carry out far better than polyurethanes. Lots of in the market were shocked when Texaco produced a video of polyurea being sprayed over ice and water without impacting the response of the components. This demonstration is usually not experienced in real-world applications. Using any covering over an excessively wet or unprimed/unprepared substrate can have harmful effects on the adhesion.

    The heat sink generally causes application issues for steel substrates. Standard polyurethane systems applied to heat sink substrates might compromise the properties or adhesion of the first pass. There are no problems using a polyurea system over prepared steel.

    Superior Malleable Toughness

    In water-proofing applications, a low modulus and a high elongation elastomer are required to fulfill the obstacle. Polyurethanes have typically been considered as having greater elongation and a lower modulus than a polyurea with a comparable hardness. Nevertheless, the days of polyurethanes having lower modulus than polyureas are over. Modern advances in the chemistry suggest

    polyurea s are created to feel as soft and elastic as polyurethane. This, in turn, opens the door for OEM makers that produce soft "vinyl-like" skins, for instance, to select polyurea. The new polyureas will extend with much less force. And, more importantly, polyureas will resist leaks and tears similarly as intensely as polyurethanes.

    Low to No Unstable Material

    Up until recently, producers have actually been confronted with the choice of shutting down production or, when it comes to large business, paying the fines and continuing with production in hopes there suffices profit margin in each system produced to keep the business operating. Modern structural polyurea systems can offer these business an alternative production product to eliminate federal government fines and increase revenues.

    Elevated Detrition Protection

    In a highly abrasive environment, polyureas carry out extremely well. In applications once thought to need high-solids epoxies, polyureas are winning at every turn. In the rail and barge market, polyureas are used rather because of their remarkable elongation and high effect resistance. Epoxies will break and delaminate when exposed to consistent pounding.

    The durability and physical properties of polyurea have actually made it the system of choice for the quickly growing truck bed lining industry. Polyurea is sprayed in a uniform texture over the metal bed surface area. Plus, thanks to innovations in application equipment, non-professional sprayer and retail applications can quickly turnover numerous trucks in an afternoon. Polyurea has actually proven its distinct advantages over polyurethane liners.

    Heat and Fire Level Of Resistance

    When it comes to heat resistance and fire retardance, polyureas have the advantage over comparably created polyurethane. Because of its formula, structural/rigid polyureas have outstanding resistance to heat distortion and drooping. At
    spray on bedliner , polyurea keeps its versatility and high impact resistance. This is not the case for molded structural polyurethane parts that are in consistent close proximity to heat. Polyurethanes tend to droop. Polyureas withstand heat sag and preserve their shape.

    And when the heat is really on, like when it comes to fire, polyureas will naturally exceed most other polymer resins. The resulting low smoke and flame spread is because of polyureas’ molecular structure. Exposed to constant flame for 20-30 seconds, polyurea will self-extinguish.

    Continued Durability

    Many polyureas are based on aliphatic isocyanate prepolymers that are highly weather resistant and color stable. Products based upon fragrant isocyanate prepolymers are not color steady and will have the tendency to chalk or darken in color with extended exposure. For a long time, fragrant polyurea was the primary version of polyurea that was promoted to the industry. In the mid-1990s, aliphatic and aliphatic-modified polyureas were developed. These products transformed the coverings service. Now end-users could safely choose a polyurea for applications that would be constantly exposed to sunshine, without worry of staining and/or chalking.

    Environmental management

    Exposed polyurea is widely used in applications such as concrete or geotextile finishes for secondary containment applications. Polyureas’ swift treatment times enable it to be quickly applied to a ready substrate with minimal downtime for the facility. This has made polyurea the choice of facility managers for walls around and floors under chemical storage of diluted acids, alkali, salt service, organic solvents and oils. Polyurea offers a strong barrier to spills from reaching the environment. In this kind of application, polyurea easily conforms to footings, pipelines and protrusions to form a complete seal. An aliphatic polyurethane or epoxy overcoat can be added for aesthetic appeals in environments that are too highly corrosive for a basic polyurea.

    Final Words

    In a world of increasing ecological awareness, polyurea proves to be an reliable and cost-effective choice for federal governments and organisations for their elastomeric and structural needs. Material enhancements in remedy times, hardness and fire retardancy are being made everyday. Application devices and spray suggestion developments are being presented more quickly than ever to satisfy the need for better, more effective ways of getting the product sprayed in place.

No Responses to “活動”

Trackbacks & Pings

  • expert-ocenka.com.ua :

    expert-ocenka.com.ua

    “月”求中秋能`”逢圓”， 我求 親情 ，友情 ， 天天似中秋情更圓。 祝大家中秋節快樂喔! – lucky小如的部落格

    6 年 ago
Translate »
跳至工具列