Cure and productivity can be further accelerated with application of heat or irradiation with ultraviolet uv energy. The main reason for such a rapid technological growth of uv curing is its unique process characteristic, which allow uv. September 27, 2012 agenda introduction to uv eb curing basic formulation strategy oligomers monomers photoinitiators cationic cure electron beam 2. They also provide strong primerless adhesion to many substrates including. In order to convert to a solid, it must be cured, vulcanized, or catalyzed. In the psm marked thermal silicone systems are most commonly used because of a brought variety of adjustable release forces and their good release properties against the used adhesives. Both are solventless and produce release coatings without the use of heat, but differ in their underlying chemistry.
The more common formulations are cured by free radical polymerization of acrylate functional resins. Uv cure 607155 is a onecomponent epoxy that cures with low intensity black light or high intensity uv lamps. Although light cure or photocure more accurately describe the chemistry, since light other than uv is used, the term. With cure speeds of less than one second, processing speeds exceed previously unobtainable levels.
Uv polymer curing is a process that uses uv light to alter the properties of a polymer, or photopolymer. Comprehensive guide to dymax uv light curing technology 1. Coating silicone silcolease uv poly 246 elkem silicones. This class of uv curable resins is often used as protective coatings for optical fibers and as potting and encapsulation of sensitive electronic elements such as sensors, connectors. Uv curing requires the addition of a photoinitiator pi. These ecologically friendly, single component, 100% solid silicone free elastomers provide a highly reliable barrier for protection against dust, liquids, gases, contaminants. In its uncured state, silicone rubber is a highlyadhesive gel or liquid.
The affected area could range from a complete non cure to a slimy or sticky surface. Fast curing, single component, no mix uv curable potting compounds offer superior electrical insulation properties. Preparation and characterization of novel uvcuring silicone. Specialty photoinitiator and radiation curing material. Preparation and characterization of novel uvcuring.
This unique chemistry allows deep sections to cure almost instantly. Other important properties include good scratch and abrasion resistance, nonyellowing, excellent optical clarity, and goodexcellent electrical properties. Uv reaction 1 cures rapidly through exposure to uv rays. Imagine flexible options for processing, protection, and. Solutions for industrial, appliance and maintenance weather resistance high resistance to ultraviolet uv rays.
Uv cure silicone rubber healthcare products momentive. Us7105584b2 dualcure silicone compounds exhibiting. These compounds protect against moisturechemicals, highlow temperature exposure, mechanicalthermal shock and vibration. In this case, the mechanical properties of uv curing silicone rubber are close to the one derived from conventional thermal radical curing system 9. Uv cure silicone rubber belongs to a new class of rubber that offers high cure speed at low temperatures. Uv a cure 1,500 resin, 9% capa 1 multifunctional polyol and 1% uv 9380 photoinitiator. Before we discuss basic silicone structures and curing mechanisms,it is necessary that the reader be familiar with simple silicone structural terminology and other common industrial terms. There are three types of uv lamps used for uv polymer curing. The chemistry and applications of uv cured adhesives m. The dual cure silicone exhibits both uv and moistureinitiated curing mechanisms, with the uv initiated curing mechanism providing very rapid curing compared to conventional dual cure silicones.
Pharos is a tool to help scientists, researchers, and product innovators identify problematic chemicals and collaborate to find safer alternatives. The chemistry and applications of uvcured adhesives. Monomers and oligomers containing acrylate unsaturation are the most commonly utilized in uv ebinitiated free radical polymerization due to their. Fast curing, low viscosity conformal coating with a uv tracer, low voc, excellent adhesion and roomlow temperature cure capability. Curing is a chemical process employed in polymer chemistry and process engineering that produces the toughening or hardening of a polymer material by crosslinking of polymer chains. Generally, the photointiator concentration will be in the range of 0. Introduction to the basics of uveb chemistry and formulations. Silicone rubbers are often one or twopart polymers, and may contain fillers to improve properties or reduce cost. This means that every surface with the wet ink, coating or adhesive must see adequate uv energy to cure. Cross sections of 5100 mm can easily be cured in very short cycle times. Identifying chemicals that cause inhibition in platinum. This rubber can be processed via injection molding with special molds, or via extrusion without additional heat to cure. Rtv silicones exhibit high performance under many harsh operating environments.
Proven neutral cure 100% silicone chemistry aggressive adhesion to a variety. Stronger bonds typically 500 4,000 psi versus 100 500 psi for silicones. Instant and complete cure is achieved by simply passing the coating under uv. The capability for adding high levels of non silicone coating extenders. Table 3 shows curing and film properties of cycloaliphatic epoxy resin modified with epoxy polyether.
Even if it is strongly associated with the production of thermosetting polymers, the term curing can be used for all the processes where starting from a liquid. The first products developed and sold were based on its patented twopart structural. In order to guarantee homogenous product performance curing time, uv tracability it is recommended to homogenize the aside prior to application by stirring. Using the 400nm wavelength as a reference, and the shape of the post exposure curves, the data for these non silicone. Meko methyl ethyl ketoxime curing reaction types and characteristics of rtv silicone rubbers viscosity before curing generally speaking. Whilst the chemistry upon which surfactants are commonly based has been around for almost exactly the same period as that of the basic silicone chemistry, it is only in the past decade that the ability to use silicone as a hydrophobic material in the preparation of surfactants has been common. Dow dowsil 36371 uv gel clear is a one component, uv and moisture curing silicone that is used for electrical insulation and protecting electrical components from contaminants, moisture, and stress. An important feature of the cure system is that no byproducts are formed, allowing fabrication of parts with good dimensional stability. Cures to form an elastic silicone rubber when exposed to either heat or room temperature. Obviously this can be a challenge for some threedimensional parts. Uv resistance good chemical resistance resistant to humidity and water no or low toxicity. Radiationcured silicone polymers for use in release liners.
We will present an overview of radiationcured silicone chemistry, use of these systems in release liner. Imagine enhance productivity, improve reliability and. This makes it ideal for bonding materials such as ceramiccoated glass, mirrors etc. Uv broadband output, dopant determines band emphasis uvc, uvb, uva. Outstanding lowtemperature flexibility and hightemperature resistance. Ul recognized under file qmju2e5148 2 low modulus, paste adhesive. Dowsil silicone sealants and foams for industrial, appliance. More about invisisil op21s uv cure optical bonding silicone an optically clear silicone molecule with a compatible photo initiator system, invisisil op21s uv cure optical bonding silicone helps enable high light transmittance and display protection to reduce surface reflection and create enhanced readability in harsh environments. Printers guide uveb chemistry and technology uv curing. Uv curable epoxies illumabond uv curable epoxy systems. These adhesives cure in seconds, thus reducing workinprocess, and offering high adhesion to silicone materials as well as plastics and metals.
Silicone cure systems silicone technologies uncured. Using uv energy, visible light, or low energy electrons as opposed to thermal, evaporative, or oxidative airdry cure to form a coating, film or ink types of energy used for energy curing. Dual cure systems also exist, which are formulated to react with. Here is a partial list of some of the more common materials that are known to cause cure inhibition. A dual cure silicone composition is provided that is useful to make an encapsulatingpotting compound. Uv curing was first introduced in the 1960s, and it is increasingly being adopted by companies as there are many advantages over prior methods of curing polymers. It is durable, fast curing, flexible, and self healing.
Uvcured transparent flexible silicone materials with high. Comprehensive guide to dymax light curing technology lit008. Dow dowsil 36371 uv silicone encapsulant clear 175 ml. Uv effects on optical silicones used in optophotonicswest. Transparent flexible silicone materials are useful in electronics, sensors, coatings, and so forth. Henkel loctite 5055 uv curing silicone adhesive 1 l bottle. The sulfurcontaining hyperbranched polycarbosilane was prepared by uv for 30 s, and the thiol silicone resin is with rsi 1. Silicone rubbers are widely used in industry, and there are multiple formulations. Cures to form and elastic silicone rubber when exposed to uv light. Extendedworkingtime moisture cure silicone coatings in this category also cure at room temperature, but permit more time for the material to flow further over large or complex boards. We will present an overview of radiationcured silicone chemistry, use of these systems in release liner applications, as well as advantages that radiationcured coatings have to offer over traditional thermallycured systems. Henkel loctite 5055 uv curing silicone adhesive 25 ml syringe description henkel loctite 5055 is a noncorrosive, low viscosity, uv visible light curing silicone adhesive designed for use in the assembly of disposable medical devices. The structural information on these silicones is shown in table 2. Introduction to the basics of uveb chemistry and formulations suny esf institute for sustainable materials and mftimanufacturing dr.
Silicone adhesive sealants use two basic silicone chemistries. To meet specific needs, silicone sealants are offered in a variety of chemistries and. Uv curing grades for forminplace and cure inplace gaskets replace diecut gaskets, rtv sealants and tape. A photopolymer is the term for a polymer that responds to uv light, which is basically invisible electromagnetic radiation. Instant and complete cure is achieved by simply passing the coating under uv or eb irradiation. Semicosil 949 uv ab room temperature curing silicone. Uv curing of silicone acrylates in thin layersa real time infrared study. Radiation curing technologies are expanding rapidly on an industrial scale and interest in cationic photopolymerizations has advanced rapidly. Uvebcurable acrylate silicones for release coatings. Ge advanced materials silicones rtv silicone rubber. There are many additional applications for uv curing, and more and more businesses are seeing the benefit of this process. They can be molded quickly at low temperatures using a typical injection molding process with uv light. Meko methyl ethyl ketoxime curing reaction types and characteristics of rtv silicone rubbers viscosity before curing.
Silicone elastomer can be crosslinked cured or vulcanized into solid forms through a variety of cure systems. This dual cure mechanism helps speed up production rates. Printers guide uveb chemistry and technology by jo ann arceneaux, allnex usa inc. The uv tracer may be subject to a limited sedimentation. High performance, noncorrosive1 fast cure ul94v0 fast cure low volatile ecc3050s rtv5220 series rtv167 rtv162 rtv3. Uv cure 607155 is a good choice for potting and encapsulating applications due to its. This unique chemistry allows paste products to cure up to 58. Uv energy cannot penetrate opaque materials to cure in shadow areas. The uv curing silicone rubber has preferable mechanical properties when the content of methylvinyl siloxane unit in gum is 0. However, to the best of our knowledge, the tensile strength of unreinforced silicone rubber is lower than 0. Rtv 800 series uv cure and uvdual cure silicone sealants. Uv 607155 is water clear and is designed to be used as an adhesive, coating, or encapsulant. First, condensation cure, which uses moisture in the atmosphere to trigger the curing process this will take place at room temperature.
Sources for radiation used in these cure chemistries are an electron accelerator ebeam and ultraviolet light uv. Even if it is strongly associated with the production of thermosetting polymers, the term curing can be used for all the processes where starting from a liquid solution, a solid product is obtained. Uv light initiates crosslinking through a photochemical reaction rather than heat. Silicone coatings are usually 1component, roomtemperature curing silicone systems that cure under the influence of moisture from the surrounding air. Overview on basic chemistry of uv curing technology vipin shukla and madhu bajpai oil and paint department h. None uv type 1 uv cure products require detailed explanation, so please contact the nearest shinetsu sales department directly. Invisisil op21s optical bonding silicone momentive. Silicone sealants typically consist of an inorganic siloxane siosiosi polymer and appropriate filler, crosslinker, catalyst, adhesion promoter, pigment and plasticizer. Review of basic chemistry of uvcuring technology article pdf available in pigment and resin technology 335. Silicone rubbers are characterized principally by the following properties. The poor mechanical property limits their further application in.
Uv cure silicone and uv dual cure silicone novagard. When a photopolymer, which can be a variety of resins, is exposed to the uv radiation, it will typically harden and. More about uv cure silicone rubber silopren uv liquid silicone rubbers lsr are twocomponent liquid silicone rubbers with a mixing ratio of 100. The level of inhibition is determined by the type as well as the amount of the chemical species that the catalyzed silicone compound comes in contact with. The acomponent contains an uv tracer that is dispersed in the silicone. The acrylate functional siloxanes cure at a rate ten times faster than their metharcylate counterparts on exposure to uveb in the presence of a photoiniator,i. This is normally carried out in a twostage process at the point of manufacture into the desired shape, and then in a prolonged post cure process. Silicone rubber is an elastomer rubberlike material composed of silicone itself a polymercontaining silicon together with carbon, hydrogen, and oxygen.
The market for ultraviolet curing technology has been growing at double. It was used for the first time in 2007 by momentive performance materials where the extruded silicone rubber figure 2 was cured at room temperature. The first is based on silicone acrylate and cures via a free radical mechanism. Dymax lcm silicone faster cures 100% cure in seconds upon exposure to light versus silicones that require exposure to humidity for 30 minutes to several days to properly cure. Smith cibageigy plastics, uk the chemistry involved in ultraviolet uv curing can be divided into two types. May 29, 2002 the capability for adding high levels of non silicone coating extenders. If desired, a moisture curable component provides for shadow curing in those areas unexposed to the ultraviolet light source. Rtv 800 series products represent a breakthrough in uv dual cure silicone technology. There are two uv curable silicone release systems on the market.
The more common formulations are cured by free radical polymerization of. These were repeated at 20% use level with 72% resin, 7% polyol and 1% photoinitiator. The dominant chemistry for uv and eb curing is the free radical polymerization of unsaturated monomers and oligomers. Coating silicone silcolease uv poly 120 u1 elkem silicones.