Industrial & Consumer Safety

The subsequent are safety procedure recommended for adhesives and sealants generally used in industrial and household environments:

Physically Hardening Adhesives: The involved components are mostly solid polymers and resins. For usage these must be converted to a liquid form. This can either be carried out by users by means of heating (hot melts) or can be carried out by glue manufacturers by dissolving the components in organic solvents or dispersing the components in water. The dry, fully-aired adhesive is usually unreactive and physically inert. There is thus usually no health risk. In contrast, there is a potential health hazard from supplementary components, such as natural solvents, that are present in some of these adhesives. These can make up as much as 80% of the mass of the adhesive product.

Hot Melts: These adhesives containmostly polymers and resins and only insignificant amounts of auxiliary materials. There is practically never a health hazard. When applying these gluesphysically, there is the threat of burns and users must guard themselves against this. During heating, little amounts of auxiliary materials, contaminants and cleavage products can be liberated, but these are unimportant when small amounts of adhesive are being processed. In an industrial or business environment, a airing system is suggesteddue to the larger quantities being used and the longer working times with the adhesives.

Organic Solvent (e.g. Contact Adhesives): In these glues the polymers and resins are dissolved in organic solvents. The danger prospective is determined by the kind of the solvent (e.g. flammability, irritation potential). Due to the high instability of the solvents, exposure by inhalation of the vapors is the biggest trouble. For the majority solvents the maximum concentration at the workplace and restrictive factors are laid down (Workplace limit value, see Glossary). Due to the small amounts of adhesive used by private users, these limit values are generally not reached or are only exceeded for a very short time.

Water-Based (e.g. PVA Wood Adhesives): In the glues the organic solvents are being replaced by water and suitable polymers are dispersed in the water. There are hence no possible health hazards from organic solvents. However, water-based adhesives are sensitive to attack by micro-organisms. For this reason dispersion adhesives contain small amounts of preservatives for protection purposes. The potential health danger is the triggering of allergic skin reactions, for example allergic reactions triggered by natural polymers such as natural rubber and non-modified colophony resins. The risk of sensitization in non-allergic people is normally very low due to the very small quantum of preservatives in the adhesives. Skin contact is here the exposure subject. Depending on the mode of application, skin contact may be inescapable, as for example when using wallpaper pastes. Though, here the concentration of preservatives is reduced as a result of mixing with water.

 Plastisols: When applying these adhesives manually, there is the danger of burns and users must protect themselves against this. During heating, small amounts of auxiliary materials, contaminants and cleavage products can be liberated, but these are insignificant when small amounts of adhesive are being processed. In an industrial or business-related environment, a ventilation system is recommended due to the larger quantities being used and the longer working times with the adhesives.

Chemically Curing: The chemically reactive monomers and hardeners and crosslinking agents decide the potential health hazard of these products. Once fully cured, the adhesive polymers are in general non-hazardous. Exposure and risk considerations therefore only apply for the time period up until the adhesives have fully cured. Chemically curing may be classified into Single Component (1C) and Two-Component (2C).

 Heat Curing (e.g. epoxies): When applying these adhesives manually, there is the threat of burns and users must guard themselves against this. During heating, small amounts of auxiliary materials, contaminants and cleavage products can be released, but these are unimportant when small amounts of adhesive are being processed. In an industrial or business-related environment, a ventilation system is suggested due to the larger quantities being used and the longer operational times with the adhesives.

 Moisture Curing (e.g. polyurethanes): This group of adhesives reacts with water from the surroundings or water on the adherend. When applying these materials, it is recommended to wear gloves, and eye protection. These materials cure over a period of hours or even days; though, contact with the skin should be minimized as they can cause several skin irritation. Vapors can cause eye annoyance and direct contact to the eyes with rubbing may cause some abrasion to them. In limited use, no additional protection is needed; however, an open area is suggested for production use. As with any moisture curing product, increasing the ambient humidity level will decrease cure time.

Cyanoacrylates: This group of adhesives reacts with water from the environment or water on the substrate. As private individuals only usually use little drops when applying the adhesive, the potential health hazard here is that if there is contact with the eyes or splashes of glue enter the eye then undesired bonding can take place. When being used industrially and commercially, possible annoyance caused by the cyanoacrylate monomer, heat effects and the rapid polymerization reaction have to be taken into deliberation. Rising the dampness prevents irritation of the respiratory tract. When doing out major joining tasks, not only is it suggested to adjust the humidity of the atmosphere but also to wear safety glasses and protecting gloves.

 Anaerobic: These categories of materials are free radical cure mechanisms and start to cure when they are confined between substrates of limited dimension, thus removing ambient air. Oxygen stabilizes these products, so the elimination of it, along with the presence of a free radical metallic ion the cure begins. A lot of of these materials containcertain amount of mild acids and acrylic monomers so the use of gloves and eye protection is advised. Generally speaking, these materials are used as threadlocking agents, bearing retaining, flange sealing and thread sealing. They can be applied via physical application from a packaged bottle, or with automated equipment. Ventilation is not usually desirable; however, in flange sealing, larger quantum are applied so open areas are often advised.

Radiation Cure: Radiation Cure is a method of commencement of the cure. It utilizes a photoinitiator as one of the raw materials in the adhesive. Once exposed to the chosen wavelength of energy (ultraviolet, visible, and even microwave) the photonitiator will react and cause the initiation of the curing process. In terms of protection, there are two concerns -- the adhesive itself, and the energy emitting source. For the adhesive, there are versions of cyanoacrylate, epoxy, silicone, anaerobic, and acrylic products all available as radiation curing. Thus, refer to the respective product descriptions in this section for handling and exposure limitations. With respect to the energy source, the first topic is microwave energy. While these materials are limited in use, they require to be mentioned, and normal concerns for microwave exposure are legitimate. These include the very same restrictions as when using microwave ovens at home - microwave energy necessarily always be protected. Use of ultraviolet light is common and requires the use of eye protection as well as skin protection to prevent burns. Many of the radiation curing adhesives utilize high intensity lights which are harmful to look at without eye protection. The same concerns are appropriate when discussing visible light cure. These materials utilize the very same idea of a photoinitiator, but it responds to a diverse wavelength of light. In this case the concern is the strength of the light source. Again, use of eye protection is essential. There are some low strength visible light curing materials, with corresponding low intensity emitting lamps, but prolonged exposure them is not advised without UV blocking eye protection as some amount of stray UV light is liable to be emitted.

 

 

 

Silicones:  Silicones: Single part silicones have very similar handling and use concerns as the single component polyurethanes as described earlier. Therefore, the similar handling methodology should be used. This group of adhesives reacts with water from the surroundings or water on the substrate. While both single and two-component materials are available, these comments refer particularly to the single component products. When applying these materials, it is suggested to wear gloves, and eye protection. These materials cure over a period of hours or even days; however, contact with the skin should be minimized as they can cause some skin irritation. Vapors can cause eye irritation and direct contact to the eyes will cause irritation. In limited use, no added protection is desirable, nevertheless, an open area is suggested for production use. As with any moisture curing product, increasing the ambient humidity level will decrease cure time.

Epoxies: Epoxy materials have both a resin and hardener, which need mixing prior to use. These parts should be used with gloves and eye protection as they can cause mild skin and eye irritation. Normally, inhalation them is not a concern; however, some people will experience some respiratory tract irritation, so open areas are suggested.

Urethanes:When a two-component polyurethane is used, the reaction for curing is the combining of the two parts. The mixed material is alike in safety related concern to the single component urethane as described above.

Methyl Methacrylates:This category of adhesives are usually used in structural bonding of metal substrates. Also identified as “MMA’s”, these materials have a strong, pungent odor, and can cause headaches, dizziness and respiratory tract irritation. They cure via the mixing of the two parts, so when handling, gloves and eye protection are recommended. They are irritating to the skin and eyes. Localized ventilation is recommended for prolonged use. Or else, application in an open area is suggested.

Silicones: Silicones react with water. Depending on the type of silicone, this reaction releases either acetic acid or alcohols. The acetic acid can be evidently sensed by the nose before any irritation begins. In general the slowly liberated amounts are so small that they present no health risk, particularly in the case of private users. Old formulations of neutral silicones which release butanone oxime necessarily be labeled, but they are only used nowadays for unique applications. It should be noted that these products can also be found as single part products.

Pressure Sensitive Adhesives: Private users only come into contact with these adhesives in the form of self-adhesive articles such as labels, adhesive tape, etc. As such these adhesives signify no hazard to private users in practice. Such articles are produced industrially using adhesives in the form of solutions, but mostly using dispersions and melts.