Uses of Polyurethane
Polyurethane products have many uses. Over three quarters of the global consumption of polyurethane products is in the form of foams, with flexible and rigid types being roughly equal in market size. In both cases, the foam is usually behind other materials: flexible foams are behind upholstery fabrics in commercial and domestic furniture; rigid foams are inside the metal and plastic walls of most refrigerators and freezers, or behind paper, metals and other surface materials in the case of thermal insulation panels in the construction sector.
The precursors of expanding polyurethane foam are available in many forms, for use in insulation, sound deadening, flotation, packing material, and even cast-in-place upholstery padding. Since they adhere to most surfaces and automatically fill voids, they have become quite popular in these applications.
Friday, January 5, 2007
Polyurethane and Production
Polyurethane and Production
Eyelids manufactured from Polyurethane:
A polyurethane is any polymer consisting of a chain of organic units joined by urethane links. It is widely used in flexible and rigid foams, durable elastomers and high performance adhesives and sealants, fibers, seals, gaskets, condoms, carpet underlay, and hard plastic parts. Polyurethane products are often called "urethanes". They should not be confused with the specific substance urethane, also known as ethyl carbamate. Polyurethanes are not produced from ethyl carbamate, nor do they contain it.
Production of Polyurethane:
The main polyurethane producing reaction is between a diisocyanate (aromatic and aliphatic types are available) and a polyol, typically a polyethylene glycol or polyester polyol, in the presence of catalysts and materials for controlling the cell structure, (surfactants) in the case of foams. Polyurethane can be made in a variety of densities and hardnesses by varying the type of monomer(s) used and adding other substances to modify their characteristics, notably density, or enhance their performance. Other additives can be used to improve the fire performance, stability in difficult chemical environments and other properties of the polyurethane products.
Though the properties of the polyurethane are determined mainly by the choice of polyol, the diisocyanate exerts some influence. The cure rate is influenced by the functional group reactivity and the number of functional isocyanate groups. The mechanical properties are influenced by the functionality and the molecular shape. The choice of diisocyanate also affects the stability of the polyurethane upon exposure to light. Polyurethanes made with aromatic diisocyanates yellow with exposure to light, whereas those made with aliphatic diisocyanates are stable.[1]
Softer, elastic, and more flexible polyurethanes result when linear difunctional polyethylene glycol segments, commonly called polyether polyols, are used to create the urethane links. This strategy is used to make spandex elastomeric fibers and soft rubber parts, as well as foam rubber. More rigid products result if polyfunctional polyols are used, as these create a three-dimensional cross-linked structure which, again, can be in the form of a low-density foam.
An even more rigid foam can be made with the use of specialty trimerization catalysts which create cyclic structures within the foam matrix, giving a harder, more thermally stable structure, designated as polyisocyanurate foams. Such properties are desired in rigid foam products used in the construction sector.
Polyurethane foam (including foam rubber) is usually made by adding small amounts of volatile materials, so-called blowing agents, to the reaction mixture. These can be simple volatile chemicals such as acetone or methylene chloride, or more sophisticated fluorocarbons which yield important performance characteristics, primarily thermal insulation.
Another common route to produce foams is the addition of water to one of the liquid precursors of polyurethane before they are mixed together. This reacts with a portion of the isocyanate, generating carbon dioxide throughout the liquid, creating relatively uniform bubbles which then harden to form a solid foam as polymerization progresses.
Eyelids manufactured from Polyurethane:
A polyurethane is any polymer consisting of a chain of organic units joined by urethane links. It is widely used in flexible and rigid foams, durable elastomers and high performance adhesives and sealants, fibers, seals, gaskets, condoms, carpet underlay, and hard plastic parts. Polyurethane products are often called "urethanes". They should not be confused with the specific substance urethane, also known as ethyl carbamate. Polyurethanes are not produced from ethyl carbamate, nor do they contain it.
Production of Polyurethane:
The main polyurethane producing reaction is between a diisocyanate (aromatic and aliphatic types are available) and a polyol, typically a polyethylene glycol or polyester polyol, in the presence of catalysts and materials for controlling the cell structure, (surfactants) in the case of foams. Polyurethane can be made in a variety of densities and hardnesses by varying the type of monomer(s) used and adding other substances to modify their characteristics, notably density, or enhance their performance. Other additives can be used to improve the fire performance, stability in difficult chemical environments and other properties of the polyurethane products.
Though the properties of the polyurethane are determined mainly by the choice of polyol, the diisocyanate exerts some influence. The cure rate is influenced by the functional group reactivity and the number of functional isocyanate groups. The mechanical properties are influenced by the functionality and the molecular shape. The choice of diisocyanate also affects the stability of the polyurethane upon exposure to light. Polyurethanes made with aromatic diisocyanates yellow with exposure to light, whereas those made with aliphatic diisocyanates are stable.[1]
Softer, elastic, and more flexible polyurethanes result when linear difunctional polyethylene glycol segments, commonly called polyether polyols, are used to create the urethane links. This strategy is used to make spandex elastomeric fibers and soft rubber parts, as well as foam rubber. More rigid products result if polyfunctional polyols are used, as these create a three-dimensional cross-linked structure which, again, can be in the form of a low-density foam.
An even more rigid foam can be made with the use of specialty trimerization catalysts which create cyclic structures within the foam matrix, giving a harder, more thermally stable structure, designated as polyisocyanurate foams. Such properties are desired in rigid foam products used in the construction sector.
Polyurethane foam (including foam rubber) is usually made by adding small amounts of volatile materials, so-called blowing agents, to the reaction mixture. These can be simple volatile chemicals such as acetone or methylene chloride, or more sophisticated fluorocarbons which yield important performance characteristics, primarily thermal insulation.
Another common route to produce foams is the addition of water to one of the liquid precursors of polyurethane before they are mixed together. This reacts with a portion of the isocyanate, generating carbon dioxide throughout the liquid, creating relatively uniform bubbles which then harden to form a solid foam as polymerization progresses.
Saturday, December 30, 2006
Difference between PolyUrethane Paintable Eyelids
WHAT IS THE DIFFERENCE BETWEEN TYPES OF EYELIDS?
Vinyl - Sticker type base product, which is very thin. Installs very easily and produces great results. Recommended to achieve excellent results at very low cost. This product is installed with adhesive on the back of the eyelids.
Polyurethane - Glossy polyurethane plastic. Works like a sticker but is thicker and more durable. It looks more like a 3D shape than it does flat. This product is installed with adhesive on the back of the eyelids.
Carbon Fiber - Glossy real 3D carbon fiber. Excellent addition to farther enhance the looks of any vehicle with a carbon fiber hood. Also a great choice for black cars. This product is installed with adhesive on the back of the eyelids.
Vinyl - Sticker type base product, which is very thin. Installs very easily and produces great results. Recommended to achieve excellent results at very low cost. This product is installed with adhesive on the back of the eyelids.
Polyurethane - Glossy polyurethane plastic. Works like a sticker but is thicker and more durable. It looks more like a 3D shape than it does flat. This product is installed with adhesive on the back of the eyelids.
Carbon Fiber - Glossy real 3D carbon fiber. Excellent addition to farther enhance the looks of any vehicle with a carbon fiber hood. Also a great choice for black cars. This product is installed with adhesive on the back of the eyelids.
Friday, December 29, 2006
Headlight Eyelids
yelids install with adhesive on top of the headlight housing of the car. It gives a sporty and aggressive look to the car.
* Brand new designed to fit every vehicle uniquely.
* Eyelids are not universal, they are pre-cut to fit exact vehicles year and model.
* Designs are measured with CNC technology for perfect accuracy.
* Eyelids are cut with state-of-the-art Computerized Smooth 100% Accurate Laser Cutting Technology. All manufacturing procedures are supervised by professional engineers.
* WHAT IS THE DIFFERENCE BETWEEN TYPES OF EYELIDSVinyl - Sticker type base product, which is very thin. Installs very easily and produces great results. Recommended to great excellent results for low cost. This product is installed with adhesive on the back of the eyelids.
* Polyurethane - Glossy polyurethane plastic. Works like a sticker but is thicker and more durable. It looks more like a 3D shape then flat shape. This product is installed with adhesive on the back of the eyelids.
* Carbon Fiber - Glossy real 3D carbon fiber. Has a 3D shape to it, real carbon fiber grain. Matches great with carbon hoods or a black car. This product is installed with adhesive on the back of the eyelids.
* Brand new designed to fit every vehicle uniquely.
* Eyelids are not universal, they are pre-cut to fit exact vehicles year and model.
* Designs are measured with CNC technology for perfect accuracy.
* Eyelids are cut with state-of-the-art Computerized Smooth 100% Accurate Laser Cutting Technology. All manufacturing procedures are supervised by professional engineers.
* WHAT IS THE DIFFERENCE BETWEEN TYPES OF EYELIDSVinyl - Sticker type base product, which is very thin. Installs very easily and produces great results. Recommended to great excellent results for low cost. This product is installed with adhesive on the back of the eyelids.
* Polyurethane - Glossy polyurethane plastic. Works like a sticker but is thicker and more durable. It looks more like a 3D shape then flat shape. This product is installed with adhesive on the back of the eyelids.
* Carbon Fiber - Glossy real 3D carbon fiber. Has a 3D shape to it, real carbon fiber grain. Matches great with carbon hoods or a black car. This product is installed with adhesive on the back of the eyelids.
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