Polyurethane PUR<\/h1><\/div><\/div><\/div><\/div><\/div>Polyurethane (PUR) is our specialty<\/h2><\/div>UW-ELAST designs, develops, and manufactures polyurethane products. We assist you from idea to delivery and application; challenge us because solid polyurethane elastomer<\/em> is an ideal construction material. <\/p>\n<\/div>Why use polyurethane?<\/h3><\/div>\n- Resistant to mechanical abrasion<\/li>\n
- Good load-bearing capacity and low compression set<\/li>\n
- Polyurethane withstands continuous working temperatures between approximately -40\u00b0C to approx. +80\u00b0C<\/li>\n
- Good resistance to water and resistance to oil, gasoline, and other similar liquids<\/li>\n
- Very strong adhesion to other materials such as metal, plastic, and similar<\/li>\n
- Has a sound-dampening effect and often lines scrap transports and equipment with similar exposure<\/li>\n<\/ul>\n<\/div><\/div><\/div>
Christer Wirheim<\/h4><\/div>Technical Sales \/ IT Manager<\/p>\n<\/div>
0501-27 94 55<\/a><\/p><\/div>christer.wirheim@uw-elast.se<\/a><\/p><\/div><\/div><\/div>\n\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t![\"Christer](\"https:\/\/www.uw-elast.se\/wp-content\/uploads\/christer-wirheim-320x320-1.jpg\")
\t\t\t<\/a>\n\t\t\t\t\t\t\t<\/div>\n<\/div><\/div><\/div><\/div><\/div><\/li>\nMikael Larsson<\/h4><\/div>Technical Sales<\/p>\n<\/div>
0501-27 94 64<\/a><\/p><\/div>mikael.larsson@uw-elast.se<\/a><\/p><\/div><\/div><\/div>\n\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t![\"Mikael](\"https:\/\/www.uw-elast.se\/wp-content\/uploads\/mikael_larsson_sm.jpg\")
\t\t\t<\/a>\n\t\t\t\t\t\t\t<\/div>\n<\/div><\/div><\/div><\/div><\/div><\/li>\nJimmy Andersson<\/h4><\/div>Technical Sales<\/p>\n<\/div>
0501-27 94 60<\/a><\/p><\/div>jimmy.andersson@uw-elast.se<\/a><\/p><\/div><\/div><\/div>\n\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t![\"Jimmy](\"https:\/\/www.uw-elast.se\/wp-content\/uploads\/jimmy-andersson-320x320-1.jpg\")
\t\t\t<\/a>\n\t\t\t\t\t\t\t<\/div>\n<\/div><\/div><\/div><\/div><\/div><\/li>\n<\/ul><\/div><\/div><\/div><\/div><\/div><\/span><\/a><\/span><\/i><\/div><\/div>What is polyurethane?<\/h2><\/div>![](\"https:\/\/www.uw-elast.se\/wp-content\/uploads\/uw-element.png\" "\\"uw-element\\"")
<\/span><\/div>Polyurethane, PUR, is a collective name for a large number of materials with varying properties.<\/strong> What they have in common is that they contain urethane groups (-NH COO-). A large number of other chemical groups, such as ester, ether, urea, biuret, allophanate groups, and double bonds, can be included in the polyurethane molecules.<\/p>\nBy mixing in pigments, fillers, fibers, various additives, and other polymers, the properties can be varied practically without limit. There is no other material group that offers the designer such great possibilities as polyurethane (PUR). <\/p>\n
Polyurethanes can be soft or hard, solid or cellular, high-damping or low-damping, brittle or impact-resistant, and have high or low water absorption.<\/p>\n<\/div>
Polyurethanes exist in various forms<\/h3><\/div>Polyurethanes are available as rubber, thermoplastics, thermoelasts, thermosets, cellular plastics, fibers, foils, rocket fuels, and as binders for paints, lacquers, and adhesives.<\/p>\n
Depending on the structure, polyurethanes can be processed in different ways. They can be reaction-molded using high-pressure or low-pressure machines, injection-molded, extruded, pressed, and foamed using several methods. <\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div>
![](\"data:image\/svg+xml,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20width%3D%271400%27%20height%3D%27933%27%20viewBox%3D%270%200%201400%20933%27%3E%3Crect%20width%3D%271400%27%20height%3D%27933%27%20fill-opacity%3D%220%22%2F%3E%3C%2Fsvg%3E\")
<\/div><\/div>Own brands within polymeric materials<\/h2><\/div><\/span><\/div>UW-ELAST har valt att arbeta med egna varum\u00e4rken eftersom det inte finns n\u00e5gon standard f\u00f6r polymera material p\u00e5 samma s\u00e4tt f\u00f6r exempelvis st\u00e5l. <\/strong>These include, for example, Slitan, Trekollan, and Vulkollan, as well as to some extent TPU, which is a thermoplastic polyurethane.<\/p>\nOne designation is Solid polyurethane<\/strong>, which is a superb construction material where properties can be varied almost infinitely. That is the challenge, and that is where we come into the picture. UW-ELAST has very long experience in this, since 1975. <\/p>\nUW-ELAST has knowledge of the material and can make adaptations for every application, so when a problem or question arises, contact us for a discussion to find the optimal technical solution.<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div>
![\"\"](\"https:\/\/www.uw-elast.se\/wp-content\/uploads\/slitan.png\")
<\/p>\n<\/div>
Slitan<\/h3><\/div>Slitan<\/strong> is particularly suitable for industrial applications such as heavy industry and the engineering industry. It can be used to manufacture structural components and to coat rollers and wheels, providing very high wear resistance.<\/p>\n<\/div><\/div><\/div>![\"Trekollan\"](\"https:\/\/www.uw-elast.se\/wp-content\/uploads\/trekollan.png\")
<\/p>\n<\/div>
Trekollan<\/h3><\/div>Trekollan<\/strong> is very suitable for applications involving abrasion, such as plow blades and concrete mixer linings.<\/p>\n<\/div><\/div><\/div>![\"\"](\"https:\/\/www.uw-elast.se\/wp-content\/uploads\/vulkollan-1.png\")
<\/p>\n<\/div>
Vulkollan<\/h3><\/div>Vulkollan<\/strong> is what is known as the “King of Urethanes.” It is suitable for coating wheels and, to some extent, rollers where there are extremely high dynamic loads. A good example of this is the Lisebergbanan roller coaster, where we have coated the wheels with Vulkollan. <\/p>\n<\/div><\/div><\/div><\/div><\/div>Material knowledge “polyurethane”<\/h3><\/div><\/i><\/i><\/span>Advice for processing Polyurethane<\/span><\/a><\/h4><\/div>\nMilling and turning<\/span><\/h3>\n\n- Use sharp, file-sharpened tool edges.<\/li>\n
- High cutting speed.<\/li>\n
- Slow feed rate.<\/li>\n
- Greater clearance than for metals.<\/li>\n
- Milling is difficult below 50 Shore A.<\/li>\n
- Cooling is recommended<\/li>\n<\/ul>\n
Drilling<\/span><\/h3>\n\n- Use twist drills.<\/li>\n
- Sharp edges.<\/li>\n
- Clearance angle 0 or negative.<\/li>\n
- Point angle 90\u2013110 for large diameters and\/or thick-walled parts, 115\u2013130 for thin-walled parts.<\/li>\n
- Slow feed (approx. 0.2 mm\/rev).<\/li>\n
- High speed.<\/li>\n
- Cooling with cutting oil.<\/li>\n<\/ul>\n
Drilling and punching<\/span><\/h3>\nThe drill should be retracted occasionally to prevent chips from blocking the hole. If a series of small holes is to be drilled, pins should be inserted into the finished holes; otherwise, the material “flows” into them and the new holes will not be round. Polyurethane<\/a> is elastic and springs back. The hole will therefore be about 4% smaller than the drill bit. For making holes in thin sheets, punching can also be used. For this purpose, sharp hollow punches mounted in a press are used. Generally, holes larger than the thickness of the polyurethane are difficult to punch. In reality, it is the strength of the punching tool that is the limitation. When punching thick sheets, the hole becomes “hourglass-shaped.” <\/p>\nSplitting<\/span><\/h3>\nA variety of methods exist for manufacturing thin sheets from thicker ones. Using so-called splitting machines, the most important part of which is a sharp knife, it is possible to manufacture very thin foils from a polyurethane cylinder. Thick sheets can also be sawn with a standard band saw. The material should then be cooled with a coolant. <\/p>\n
Read more about polyurethane sheets here<\/a>.<\/p>\nBonding of polyurethane<\/span><\/h3>\nIt is easiest to achieve good adhesion if the polyurethane is not fully cured. If the polyurethane is fully cured, the surface must be roughened or blasted with steel grit. The surface must then be made very clean from dirt and release agents. A major problem is silicone oil-based release agents, which are difficult to remove completely. <\/p>\n
For bonding polyurethanes, polyurethane adhesives or fairly flexible epoxy adhesives are best suited. The adhesive should provide a joint that has lower stiffness than the polyurethane; otherwise, there is a risk of the joint breaking under bending loads.<\/div><\/div><\/div>
<\/i><\/i><\/span>Electrical properties<\/span><\/a><\/h4><\/div>\nEpoxy resins, polyurethanes<\/a>, and silicone rubber are mainly used as potting compounds for electrical and electronic components. Each material group has its advantages and limitations. <\/p>\n\n\n\n\n\n\n\n\nSilicone rubber<\/h3>\n
Silicone rubber has superior temperature resistance and, at the same time, the best low-temperature properties. Furthermore, silicone rubber has a very low dielectric constant and a very low dielectric loss factor. This means that silicone rubber is not heated by, for example, microwaves. In the event of a fire, only a small amount of toxic gases is developed, and the ash, which consists of silicon dioxide, is electrically insulating, in contrast to the ash from polyurethane and epoxy. <\/p>\n
Limitations for silicone rubber include a very high price, high water permeability, and relatively poor mechanical properties compared to epoxy and polyurethanes. The latter, however, does not always have to be a disadvantage; for example, it can facilitate the repair of encapsulated components. <\/p>\n
Polyurethane and epoxy<\/h3>\n
The materials that compete most closely with each other are polyurethane and epoxy. Both have their advantages and limitations; which material is best depends entirely on the application. <\/p>\n
Compared to epoxy, however, polyurethane has the following advantages:<\/p>\n
\n- Greater range of variations.<\/li>\n<\/ul>\n
\n- Lower heat generation during curing.<\/li>\n<\/ul>\n
\n- Lower shrinkage during curing, resulting in lower shrinkage stresses.<\/li>\n<\/ul>\n
\n- On average, better dielectric strength.<\/li>\n<\/ul>\n
\n- Shorter curing time.<\/li>\n<\/ul>\n
Epoxy, however, has lower water absorption, higher volume resistivity, and a lower dielectric constant than polyurethanes.<\/p>\n
Important electrical properties<\/h3>\n
Important electrical properties include volume and surface resistivity, dielectric constant, dielectric strength, dielectric loss factor, arc resistance, and tracking resistance.<\/p>\n
Other important properties for potting compounds include low flammability, insulation capacity after fire, water vapor permeability, corona resistance, ozone resistance, moisture absorption, aging resistance, and good mechanical properties. Self-extinguishing polyurethanes corresponding to UL 94 V0 can be obtained by mixing, for example, aluminum trihydrate into the casting compound. <\/p>\n
Like mechanical properties, electrical properties change more or less with the surrounding environment, frequency, and aging.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div><\/div><\/div>
<\/i><\/i><\/span>Compressive loads<\/span><\/a><\/h4><\/div>Under compressive load, rubber behaves like an incompressible liquid \u2013 when rubber is compressed, the shape changes but not the volume. In contrast to a liquid, however, rubber returns more or less to its original shape. These properties and the design of the rubber component affect how much it is compressed at a certain load. The fact that rubber is not compressible must be taken into account during design. Solid rubber must always have the possibility to bulge out under compressive load and must absolutely not be enclosed. <\/p>\nCompressive load and tensile load<\/h3>\n
Rubber is mostly used under compressive loads, and most types of rubber, apart from urethane rubber<\/a>, silicone rubber, and EPDM rubber<\/a>, have a significantly shorter lifespan under tensile load than under compressive load. How the rubber behaves under compressive load is of great importance for its function. An important property is how much the rubber deforms at a certain load. A certain deformation may be desirable, e.g., when using rubber for vibration dampers.<\/div><\/div><\/div>
Polyurethane (PUR) is our specialty<\/h2><\/div>UW-ELAST designs, develops, and manufactures polyurethane products. We assist you from idea to delivery and application; challenge us because solid polyurethane elastomer<\/em> is an ideal construction material. <\/p>\n<\/div>Why use polyurethane?<\/h3><\/div>\n- Resistant to mechanical abrasion<\/li>\n
- Good load-bearing capacity and low compression set<\/li>\n
- Polyurethane withstands continuous working temperatures between approximately -40\u00b0C to approx. +80\u00b0C<\/li>\n
- Good resistance to water and resistance to oil, gasoline, and other similar liquids<\/li>\n
- Very strong adhesion to other materials such as metal, plastic, and similar<\/li>\n
- Has a sound-dampening effect and often lines scrap transports and equipment with similar exposure<\/li>\n<\/ul>\n<\/div><\/div><\/div>
Christer Wirheim<\/h4><\/div>Technical Sales \/ IT Manager<\/p>\n<\/div>
0501-27 94 55<\/a><\/p><\/div>christer.wirheim@uw-elast.se<\/a><\/p><\/div><\/div><\/div>\n\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t<\/div>\n<\/div><\/div><\/div><\/div><\/div><\/li>\nMikael Larsson<\/h4><\/div>Technical Sales<\/p>\n<\/div>
0501-27 94 64<\/a><\/p><\/div>mikael.larsson@uw-elast.se<\/a><\/p><\/div><\/div><\/div>\n\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t<\/div>\n<\/div><\/div><\/div><\/div><\/div><\/li>\nJimmy Andersson<\/h4><\/div>Technical Sales<\/p>\n<\/div>
0501-27 94 60<\/a><\/p><\/div>jimmy.andersson@uw-elast.se<\/a><\/p><\/div><\/div><\/div>\n\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t<\/div>\n<\/div><\/div><\/div><\/div><\/div><\/li>\n<\/ul><\/div><\/div><\/div><\/div><\/div><\/span><\/a><\/span><\/i><\/div><\/div>What is polyurethane?<\/h2><\/div><\/span><\/div>Polyurethane, PUR, is a collective name for a large number of materials with varying properties.<\/strong> What they have in common is that they contain urethane groups (-NH COO-). A large number of other chemical groups, such as ester, ether, urea, biuret, allophanate groups, and double bonds, can be included in the polyurethane molecules.<\/p>\nBy mixing in pigments, fillers, fibers, various additives, and other polymers, the properties can be varied practically without limit. There is no other material group that offers the designer such great possibilities as polyurethane (PUR). <\/p>\n
Polyurethanes can be soft or hard, solid or cellular, high-damping or low-damping, brittle or impact-resistant, and have high or low water absorption.<\/p>\n<\/div>
Polyurethanes exist in various forms<\/h3><\/div>Polyurethanes are available as rubber, thermoplastics, thermoelasts, thermosets, cellular plastics, fibers, foils, rocket fuels, and as binders for paints, lacquers, and adhesives.<\/p>\n
Depending on the structure, polyurethanes can be processed in different ways. They can be reaction-molded using high-pressure or low-pressure machines, injection-molded, extruded, pressed, and foamed using several methods. <\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div>
<\/div><\/div>Own brands within polymeric materials<\/h2><\/div><\/span><\/div>UW-ELAST har valt att arbeta med egna varum\u00e4rken eftersom det inte finns n\u00e5gon standard f\u00f6r polymera material p\u00e5 samma s\u00e4tt f\u00f6r exempelvis st\u00e5l. <\/strong>These include, for example, Slitan, Trekollan, and Vulkollan, as well as to some extent TPU, which is a thermoplastic polyurethane.<\/p>\nOne designation is Solid polyurethane<\/strong>, which is a superb construction material where properties can be varied almost infinitely. That is the challenge, and that is where we come into the picture. UW-ELAST has very long experience in this, since 1975. <\/p>\nUW-ELAST has knowledge of the material and can make adaptations for every application, so when a problem or question arises, contact us for a discussion to find the optimal technical solution.<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div>
<\/p>\n<\/div>
Slitan<\/h3><\/div>Slitan<\/strong> is particularly suitable for industrial applications such as heavy industry and the engineering industry. It can be used to manufacture structural components and to coat rollers and wheels, providing very high wear resistance.<\/p>\n<\/div><\/div><\/div><\/p>\n<\/div>
Trekollan<\/h3><\/div>Trekollan<\/strong> is very suitable for applications involving abrasion, such as plow blades and concrete mixer linings.<\/p>\n<\/div><\/div><\/div><\/p>\n<\/div>
Vulkollan<\/h3><\/div>Vulkollan<\/strong> is what is known as the “King of Urethanes.” It is suitable for coating wheels and, to some extent, rollers where there are extremely high dynamic loads. A good example of this is the Lisebergbanan roller coaster, where we have coated the wheels with Vulkollan. <\/p>\n<\/div><\/div><\/div><\/div><\/div>Material knowledge “polyurethane”<\/h3><\/div><\/i><\/i><\/span>Advice for processing Polyurethane<\/span><\/a><\/h4><\/div>\nMilling and turning<\/span><\/h3>\n\n- Use sharp, file-sharpened tool edges.<\/li>\n
- High cutting speed.<\/li>\n
- Slow feed rate.<\/li>\n
- Greater clearance than for metals.<\/li>\n
- Milling is difficult below 50 Shore A.<\/li>\n
- Cooling is recommended<\/li>\n<\/ul>\n
Drilling<\/span><\/h3>\n\n- Use twist drills.<\/li>\n
- Sharp edges.<\/li>\n
- Clearance angle 0 or negative.<\/li>\n
- Point angle 90\u2013110 for large diameters and\/or thick-walled parts, 115\u2013130 for thin-walled parts.<\/li>\n
- Slow feed (approx. 0.2 mm\/rev).<\/li>\n
- High speed.<\/li>\n
- Cooling with cutting oil.<\/li>\n<\/ul>\n
Drilling and punching<\/span><\/h3>\nThe drill should be retracted occasionally to prevent chips from blocking the hole. If a series of small holes is to be drilled, pins should be inserted into the finished holes; otherwise, the material “flows” into them and the new holes will not be round. Polyurethane<\/a> is elastic and springs back. The hole will therefore be about 4% smaller than the drill bit. For making holes in thin sheets, punching can also be used. For this purpose, sharp hollow punches mounted in a press are used. Generally, holes larger than the thickness of the polyurethane are difficult to punch. In reality, it is the strength of the punching tool that is the limitation. When punching thick sheets, the hole becomes “hourglass-shaped.” <\/p>\nSplitting<\/span><\/h3>\nA variety of methods exist for manufacturing thin sheets from thicker ones. Using so-called splitting machines, the most important part of which is a sharp knife, it is possible to manufacture very thin foils from a polyurethane cylinder. Thick sheets can also be sawn with a standard band saw. The material should then be cooled with a coolant. <\/p>\n
Read more about polyurethane sheets here<\/a>.<\/p>\nBonding of polyurethane<\/span><\/h3>\nIt is easiest to achieve good adhesion if the polyurethane is not fully cured. If the polyurethane is fully cured, the surface must be roughened or blasted with steel grit. The surface must then be made very clean from dirt and release agents. A major problem is silicone oil-based release agents, which are difficult to remove completely. <\/p>\n
For bonding polyurethanes, polyurethane adhesives or fairly flexible epoxy adhesives are best suited. The adhesive should provide a joint that has lower stiffness than the polyurethane; otherwise, there is a risk of the joint breaking under bending loads.<\/div><\/div><\/div>
<\/i><\/i><\/span>Electrical properties<\/span><\/a><\/h4><\/div>\nEpoxy resins, polyurethanes<\/a>, and silicone rubber are mainly used as potting compounds for electrical and electronic components. Each material group has its advantages and limitations. <\/p>\n\n\n\n\n\n\n\n\nSilicone rubber<\/h3>\n
Silicone rubber has superior temperature resistance and, at the same time, the best low-temperature properties. Furthermore, silicone rubber has a very low dielectric constant and a very low dielectric loss factor. This means that silicone rubber is not heated by, for example, microwaves. In the event of a fire, only a small amount of toxic gases is developed, and the ash, which consists of silicon dioxide, is electrically insulating, in contrast to the ash from polyurethane and epoxy. <\/p>\n
Limitations for silicone rubber include a very high price, high water permeability, and relatively poor mechanical properties compared to epoxy and polyurethanes. The latter, however, does not always have to be a disadvantage; for example, it can facilitate the repair of encapsulated components. <\/p>\n
Polyurethane and epoxy<\/h3>\n
The materials that compete most closely with each other are polyurethane and epoxy. Both have their advantages and limitations; which material is best depends entirely on the application. <\/p>\n
Compared to epoxy, however, polyurethane has the following advantages:<\/p>\n
\n- Greater range of variations.<\/li>\n<\/ul>\n
\n- Lower heat generation during curing.<\/li>\n<\/ul>\n
\n- Lower shrinkage during curing, resulting in lower shrinkage stresses.<\/li>\n<\/ul>\n
\n- On average, better dielectric strength.<\/li>\n<\/ul>\n
\n- Shorter curing time.<\/li>\n<\/ul>\n
Epoxy, however, has lower water absorption, higher volume resistivity, and a lower dielectric constant than polyurethanes.<\/p>\n
Important electrical properties<\/h3>\n
Important electrical properties include volume and surface resistivity, dielectric constant, dielectric strength, dielectric loss factor, arc resistance, and tracking resistance.<\/p>\n
Other important properties for potting compounds include low flammability, insulation capacity after fire, water vapor permeability, corona resistance, ozone resistance, moisture absorption, aging resistance, and good mechanical properties. Self-extinguishing polyurethanes corresponding to UL 94 V0 can be obtained by mixing, for example, aluminum trihydrate into the casting compound. <\/p>\n
Like mechanical properties, electrical properties change more or less with the surrounding environment, frequency, and aging.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div><\/div><\/div>
<\/i><\/i><\/span>Compressive loads<\/span><\/a><\/h4><\/div>Under compressive load, rubber behaves like an incompressible liquid \u2013 when rubber is compressed, the shape changes but not the volume. In contrast to a liquid, however, rubber returns more or less to its original shape. These properties and the design of the rubber component affect how much it is compressed at a certain load. The fact that rubber is not compressible must be taken into account during design. Solid rubber must always have the possibility to bulge out under compressive load and must absolutely not be enclosed. <\/p>\nCompressive load and tensile load<\/h3>\n
Rubber is mostly used under compressive loads, and most types of rubber, apart from urethane rubber<\/a>, silicone rubber, and EPDM rubber<\/a>, have a significantly shorter lifespan under tensile load than under compressive load. How the rubber behaves under compressive load is of great importance for its function. An important property is how much the rubber deforms at a certain load. A certain deformation may be desirable, e.g., when using rubber for vibration dampers.<\/div><\/div><\/div>
UW-ELAST designs, develops, and manufactures polyurethane products. We assist you from idea to delivery and application; challenge us because solid polyurethane elastomer<\/em> is an ideal construction material. <\/p>\n<\/div> Technical Sales \/ IT Manager<\/p>\n<\/div> 0501-27 94 55<\/a><\/p><\/div> christer.wirheim@uw-elast.se<\/a><\/p><\/div><\/div><\/div> Technical Sales<\/p>\n<\/div> 0501-27 94 64<\/a><\/p><\/div> mikael.larsson@uw-elast.se<\/a><\/p><\/div><\/div><\/div> Technical Sales<\/p>\n<\/div> 0501-27 94 60<\/a><\/p><\/div> jimmy.andersson@uw-elast.se<\/a><\/p><\/div><\/div><\/div> Polyurethane, PUR, is a collective name for a large number of materials with varying properties.<\/strong> What they have in common is that they contain urethane groups (-NH COO-). A large number of other chemical groups, such as ester, ether, urea, biuret, allophanate groups, and double bonds, can be included in the polyurethane molecules.<\/p>\n By mixing in pigments, fillers, fibers, various additives, and other polymers, the properties can be varied practically without limit. There is no other material group that offers the designer such great possibilities as polyurethane (PUR). <\/p>\n Polyurethanes can be soft or hard, solid or cellular, high-damping or low-damping, brittle or impact-resistant, and have high or low water absorption.<\/p>\n<\/div> Polyurethanes are available as rubber, thermoplastics, thermoelasts, thermosets, cellular plastics, fibers, foils, rocket fuels, and as binders for paints, lacquers, and adhesives.<\/p>\n Depending on the structure, polyurethanes can be processed in different ways. They can be reaction-molded using high-pressure or low-pressure machines, injection-molded, extruded, pressed, and foamed using several methods. <\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div> UW-ELAST har valt att arbeta med egna varum\u00e4rken eftersom det inte finns n\u00e5gon standard f\u00f6r polymera material p\u00e5 samma s\u00e4tt f\u00f6r exempelvis st\u00e5l. <\/strong>These include, for example, Slitan, Trekollan, and Vulkollan, as well as to some extent TPU, which is a thermoplastic polyurethane.<\/p>\n One designation is Solid polyurethane<\/strong>, which is a superb construction material where properties can be varied almost infinitely. That is the challenge, and that is where we come into the picture. UW-ELAST has very long experience in this, since 1975. <\/p>\n UW-ELAST has knowledge of the material and can make adaptations for every application, so when a problem or question arises, contact us for a discussion to find the optimal technical solution.<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div> Slitan<\/strong> is particularly suitable for industrial applications such as heavy industry and the engineering industry. It can be used to manufacture structural components and to coat rollers and wheels, providing very high wear resistance.<\/p>\n<\/div><\/div><\/div> Trekollan<\/strong> is very suitable for applications involving abrasion, such as plow blades and concrete mixer linings.<\/p>\n<\/div><\/div><\/div> Vulkollan<\/strong> is what is known as the “King of Urethanes.” It is suitable for coating wheels and, to some extent, rollers where there are extremely high dynamic loads. A good example of this is the Lisebergbanan roller coaster, where we have coated the wheels with Vulkollan. <\/p>\n<\/div><\/div><\/div><\/div><\/div> The drill should be retracted occasionally to prevent chips from blocking the hole. If a series of small holes is to be drilled, pins should be inserted into the finished holes; otherwise, the material “flows” into them and the new holes will not be round. Polyurethane<\/a> is elastic and springs back. The hole will therefore be about 4% smaller than the drill bit. For making holes in thin sheets, punching can also be used. For this purpose, sharp hollow punches mounted in a press are used. Generally, holes larger than the thickness of the polyurethane are difficult to punch. In reality, it is the strength of the punching tool that is the limitation. When punching thick sheets, the hole becomes “hourglass-shaped.” <\/p>\n A variety of methods exist for manufacturing thin sheets from thicker ones. Using so-called splitting machines, the most important part of which is a sharp knife, it is possible to manufacture very thin foils from a polyurethane cylinder. Thick sheets can also be sawn with a standard band saw. The material should then be cooled with a coolant. <\/p>\n Read more about polyurethane sheets here<\/a>.<\/p>\n It is easiest to achieve good adhesion if the polyurethane is not fully cured. If the polyurethane is fully cured, the surface must be roughened or blasted with steel grit. The surface must then be made very clean from dirt and release agents. A major problem is silicone oil-based release agents, which are difficult to remove completely. <\/p>\n For bonding polyurethanes, polyurethane adhesives or fairly flexible epoxy adhesives are best suited. The adhesive should provide a joint that has lower stiffness than the polyurethane; otherwise, there is a risk of the joint breaking under bending loads.<\/div><\/div><\/div> Epoxy resins, polyurethanes<\/a>, and silicone rubber are mainly used as potting compounds for electrical and electronic components. Each material group has its advantages and limitations. <\/p>\n Silicone rubber has superior temperature resistance and, at the same time, the best low-temperature properties. Furthermore, silicone rubber has a very low dielectric constant and a very low dielectric loss factor. This means that silicone rubber is not heated by, for example, microwaves. In the event of a fire, only a small amount of toxic gases is developed, and the ash, which consists of silicon dioxide, is electrically insulating, in contrast to the ash from polyurethane and epoxy. <\/p>\n Limitations for silicone rubber include a very high price, high water permeability, and relatively poor mechanical properties compared to epoxy and polyurethanes. The latter, however, does not always have to be a disadvantage; for example, it can facilitate the repair of encapsulated components. <\/p>\n The materials that compete most closely with each other are polyurethane and epoxy. Both have their advantages and limitations; which material is best depends entirely on the application. <\/p>\n Compared to epoxy, however, polyurethane has the following advantages:<\/p>\n Epoxy, however, has lower water absorption, higher volume resistivity, and a lower dielectric constant than polyurethanes.<\/p>\n Important electrical properties include volume and surface resistivity, dielectric constant, dielectric strength, dielectric loss factor, arc resistance, and tracking resistance.<\/p>\n Other important properties for potting compounds include low flammability, insulation capacity after fire, water vapor permeability, corona resistance, ozone resistance, moisture absorption, aging resistance, and good mechanical properties. Self-extinguishing polyurethanes corresponding to UL 94 V0 can be obtained by mixing, for example, aluminum trihydrate into the casting compound. <\/p>\n Like mechanical properties, electrical properties change more or less with the surrounding environment, frequency, and aging.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div><\/div><\/div> Rubber is mostly used under compressive loads, and most types of rubber, apart from urethane rubber<\/a>, silicone rubber, and EPDM rubber<\/a>, have a significantly shorter lifespan under tensile load than under compressive load. How the rubber behaves under compressive load is of great importance for its function. An important property is how much the rubber deforms at a certain load. A certain deformation may be desirable, e.g., when using rubber for vibration dampers.<\/div><\/div><\/div>Why use polyurethane?<\/h3><\/div>
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Christer Wirheim<\/h4><\/div>
\t\t\t<\/a>\n\t\t\t\t\t\t\t<\/div>\n<\/div><\/div><\/div><\/div><\/div><\/li>\nMikael Larsson<\/h4><\/div>
\t\t\t<\/a>\n\t\t\t\t\t\t\t<\/div>\n<\/div><\/div><\/div><\/div><\/div><\/li>\nJimmy Andersson<\/h4><\/div>
\t\t\t<\/a>\n\t\t\t\t\t\t\t<\/div>\n<\/div><\/div><\/div><\/div><\/div><\/li>\n<\/ul><\/div><\/div><\/div><\/div><\/div>What is polyurethane?<\/h2><\/div>
<\/span><\/div>Polyurethanes exist in various forms<\/h3><\/div>
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Own brands within polymeric materials<\/h2><\/div>
<\/span><\/div><\/p>\n<\/div>Slitan<\/h3><\/div>
<\/p>\n<\/div>Trekollan<\/h3><\/div>
<\/p>\n<\/div>Vulkollan<\/h3><\/div>
Material knowledge “polyurethane”<\/h3><\/div>
<\/i><\/i><\/span>Advice for processing Polyurethane<\/span><\/a><\/h4><\/div>
Milling and turning<\/span><\/h3>\n
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Drilling<\/span><\/h3>\n
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Drilling and punching<\/span><\/h3>\n
Splitting<\/span><\/h3>\n
Bonding of polyurethane<\/span><\/h3>\n
<\/i><\/i><\/span>Electrical properties<\/span><\/a><\/h4><\/div>
Silicone rubber<\/h3>\n
Polyurethane and epoxy<\/h3>\n
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Important electrical properties<\/h3>\n
<\/i><\/i><\/span>Compressive loads<\/span><\/a><\/h4><\/div>
Compressive load and tensile load<\/h3>\n
![\"polyurethane](\"https:\/\/www.uw-elast.se\/wp-content\/uploads\/2017\/10\/polyuretan-gummi_0.gif\")
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