Keywords

Adhesives; material safety data sheet; OSHA; HCS; HMIS

14.1 Safety

Adhesives consist of a number of components as described in Chapter 6, usually containing reactive chemicals. Adequate precautions must be taken when working with adhesives to prevent harmful exposure. Adhesives manufacturers are required by law to provide a material safety data sheet (MSDS) for each product that they sell. The MSDS must contain sufficient details about the composition, hazard rating, first aid measures, handling and storage, personal protection (exposure control), stability and reactivity, and toxicology of adhesives.

Anyone who plans to handle an adhesive must be familiar with the measures required to prevent or minimize exposure of personnel. In addition to volatile organic solvents and resins, adhesives may contain pigments, catalysts, stabilizer, extenders, etc. Each of these components may possess hazardous properties individually or in combination with other materials. There are thousands of adhesive compounds on the market making it impractical to list the hazards of every one of them [1]. The current system of communication required by law is described below to allow the reader to decipher the safety information provided by adhesives manufacturers. This system is applicable to all chemicals.

Adhesives, as with other chemicals, must meet the standards of personal safety established by the Occupational Safety and Health Administration (OSHA) [2,3]. The need to protect employees from the hazards of such chemicals led OSHA to issue the first Hazard Communication Standard (HCS) in 1983. The central idea of the HCS is the belief that workers who may be exposed to hazardous chemicals have a right to know about the hazards and how to work safely with the materials. As a result, the standard requires that chemical manufacturers and importers evaluate all chemicals for hazards, and that the information concerning those hazards be communicated downstream from the manufacturer to the employer and then to the employee.

The HCS has three basic requirements:

The Hazardous Material Identification System (HMIS) helps to satisfy HCS requirements by providing a format for hazard determinations, offering a basic written hazard communication program, and simplifying the employee training and information process [2,3]. HMIS provides clear, recognizable information to employees by standardizing the presentation of chemical information. This is accomplished by the use of color codes corresponding to the hazards of a product, assigned numeric ratings (Table 14.1 and Figure 14.1) indication of the degree of hazard, and alphabetical codes designating appropriate personal protective equipment (PPE) that employees should wear while handling the material (Table 14.2). Of particular significance is inhalation and flammability risks encountered with solvent-based compositions. The volatility of the solvents selected for adhesive formulation is high to aid in their removal.

The American Coatings Association [4] has developed the Hazardous Materials Identification System (HMIS®) to aid employers in the implementation of an effective Hazard Communication Program. The third version of this system, HMIS® III, offers comprehensive resources covering hazard assessment, hazard communication, and employee training. HMIS® III Hazard Assessment helps define the health, flammability and physical hazards of different chemicals, and shows how to communicate those hazards via a label that incorporates color-coded fields, along with a recommendation for PPE.

The lettering system in Table 14.2 indicates the level of PPE to be worn to work safely with a material. The original system traditionally provided letters of the alphabet corresponding to a specific grouping of PPE. However, this did not allow employers to customize their PPE recommendations. Now employers who cannot find an appropriate grouping of PPE will be able to design their own custom set of equipment. Each of the individual PPE icons has been designated with a corresponding letter of the alphabet ranging from “m” to “z.” An employer can list appropriate letters to customize the PPE required for handling a specific material. To facilitate this option, container labels have been revised to allow room for the additional codes in the PPE block of the label. Of course, employers who find the previous PPE groupings suitable for their workplaces can continue to use the standard codes.

The National Fire Protection Association [5] (NFPA) has developed a color-coded number system called NFPA 704 (Figure 14.2). It uses a color-coded diamond with four quadrants in which numbers are used in the upper three quadrants to signal the degree of health hazard (blue), flammability hazard (red), and reactivity hazard (yellow). The bottom quadrant is used to indicate special hazards. The NFPA system alerts the personnel about the degree of hazard of the chemical. It also draws attention to storage needs and required emergency equipment.

Another feature of HMIS that differs from the NFPA label system is that it allows an asterisk to designate a material as a carcinogen or for materials known to have an adverse effect from chronic exposure. This designation would appear next to the numerical ranking within the blue health bar. This information is of great benefit to laboratory workers, as this is an indication of how the material will affect them in the long run. Recall that, in comparison, the NFPA rating indicates only the short-term or acute effects you might encounter in an emergency circumstance.

Adhesives, as with other chemicals, fall within the jurisdiction of a number of laws. Table 14.3 gives a list of acronyms and the full names of these legal acts. Table 14.4 decodes a number of other acronyms that may be encountered in MSDSs.

Care should be taken when applying adhesives. At the least, an air-filtering mask that is designed to provide protection from airborne particulates should be worn. Good ventilation is recommended for all adhesive applications. Ventilation hoods may be necessary for certain types of adhesives and building designs.

Additional protection may be required when applying water-based natural latex adhesives. Persons allergic to latex should not apply the product. Some carriers, such as formulations containing acetone, may have a low flash point, therefore requiring specialized fire detection and suppression equipment. Be sure to consult the manufacturer’s MSDS for additional handling, storage, and application safety information. Insurance carriers are also good sources of information regarding proper use and ventilation of adhesive application areas [6].

14.2 Environmental Considerations

Adhesion requires the use of a variety of compounds that may be safe, hazardous, or flammable, or form hazardous waste. There has been extensive collaboration between the industry and the governmental environmental protection agencies to reduce all emissions. For instance, the Design for Environment (DfE) program in the Environmental Protection Agency’s (EPA) Office of Pollution Prevention and Toxics has been a voluntary partnership with the industry to develop and distribute pollution prevention and environmental and human health risks on alternative chemicals, processes, and products. The DfE approach uses cleaner technologies substitute assessments (CTSAs) and life cycle tools to evaluate current and emerging technologies [7,8].

The CTSA is a method of systematically evaluating and comparing human health and environmental risk, competitiveness (issues, such as performance and cost), and resource requirements of the traditional and alternative chemicals, and manufacturing technologies to perform the same function. Furniture adhesives have utilized CTSA for assistance in decision making to incorporate environmental concerns, performance, cost, and the selection of an adhesives technology. The adhesives that bond porous substrates are an example of the application of CTSA, where traditional solvent carriers were subjected to more stringent regulations [9]. New adhesive formulations, improved processes, and preventive measures have been developed to reduce environmental emissions and worker exposure without sacrificing the economics of the manufacturing.

Additional information can be obtained by contacting the US EPA (www.USEPA.com) or individual companies.

14.3 Economics

Adhesives are extremely important components of most fabricated products. They play a functional role that is nearly always invisible. Because of their enabling role, users and consumers notice an adhesive only when it fails. The nature of the adhesives’ function has placed pressure on the prices of adhesives. The economics of non-specialty adhesives have followed the path of other commodities. At the same time, performance requirements have escalated over time. A great deal of consolidation has taken place among the manufacturers of adhesives (and sealants).

Research activity has slowed down in the industry due to technological maturity in the traditional adhesives. The industry is attempting to revive research by focus on process technology know-how and newer approaches such as nanotechnology. Trade associations, including the Adhesive and Sealant Council, Inc. (ASC), are engaged in leading renewal initiatives.

New regulations have focused on environmental emissions and waste disposal. These trends have been ongoing in North America, Europe, and Japan for decades. A more recent phenomenon is the start of promulgation of similar rules in the developing regions, especially China.

Waterborne systems have been dominating the North American market for decades [10]. The share of the solvent-based systems has continued to decrease significantly since the 1980s. The consumption of solvents has decreased much more significantly by conversion from the low to high solids formulas. The one-part adhesives (nonvolatile), including epoxies, cyanoacrylates, and urethanes, have made large inroads, nearly tripling their share of the market in the last three decades.

Globalization continues to intensify the competition and pressure on adhesives prices because of the lower cost of production in developing regions of the world. Customers and capital markets are increasingly more global. A great deal of consolidation has taken place in the adhesives industry. Further mergers and acquisitions can be expected in the future, thus reducing the number of suppliers and enlarging the newer companies. The Adhesives & Sealants Industry magazine ranks the ASI Top 25 manufacturers based on adhesive and sealants revenues (Table 14.6).

According to the “Adhesives and Adhesive Applicators: Technologies and Global Markets” report from BCC Research, the global market for adhesives and adhesive applying equipment is projected to reach $41.1 billion in 2013 and $42.8 billion in 2014. The market is expected to grow to $51.4 billion by 2019 at a compound annual growth rate (CAGR) of 3.7% [12]. The increasing need for weight reduction of end user products, high bonding solutions, sustainable developments, growing tape demand, rising Growth Domestic Products, and purchasing power are all expected to drive the global pressure sensitive adhesives (PSAs) market to $8.4 billion [13].

14.4 Future Trends

The trends in adhesives use are influenced by a number of factors that influence a number of other industrial commodities. Globalization, technological maturity, and increased government regulations have been the key drivers of adhesives trends.

Europe, Japan, and the United States have long represented the majority of adhesives consumption. Developing regions of the Middle East and Asia-Pacific region, led by countries such as China, India, Taiwan, Vietnam, and South Korea, are expected to drive future growth in adhesives and sealants, according to a recent report by Global Industry Analysts, Inc. (www.strategyr.com). The rapid pace of industrialization, strong GDP growth, and a rise in manufacturing and industrial output represent key growth drivers in these regions. India stands as an upcoming market for aggressive investments by global majors. In South America, Brazil and Argentina are emerging as promising markets for adhesives [14].

Environmental concerns and regulations continue to be a concern for adhesive manufacturers. Formulation and production of environmentally friendly products like solvent-free adhesives are growing in popularity. Manufacturers are increasingly investing in manufacturing and product development programs to engineer green adhesives based on vegetable oils, organic starch, soy, and water. The manufacture of polyurethane adhesives derived from microbial processes and fermentation is growing in popularity. Adhesives manufacturers have displayed strong interest in vegetable oils, which are used increasingly in formulating efficient adhesives like polyamides that compete effectively against petroleum-derived adhesives. The trend toward recycling and safe disposal of waste will also strengthen in the coming years. The increasing use of high-performance adhesives in medical applications is another growth driver for the market. A growing need for dental and surgical adhesives, as a result of the aging population, is also benefiting demand in this sector. Cyanoacrylate adhesives dominate the market for medical adhesives [14].

An increased focus on renewable energy is also opening up opportunities for adhesives manufacturers. The push towards a viable renewable energy source has brought solar photovoltaic power technology to the forefront, and manufacturing of solar panels is forecast to emerge into one of the most crucial application areas for adhesives.

The miniaturization trend in electronics is another factor spurring demand, particularly for conductive adhesives. Miniaturization of electronics has popularized system-on-chip (SoC) technology, where specialized adhesives find mission-critical applications. Electrically and thermally conductive adhesives or polymer-based binding agents are used in antivibration shock mounting of circuit boards. Technology developments that improve the conductivity properties of conductive adhesives will drive demand in the market. Europe continues to remain the largest regional market worldwide, according to the report by Global Industry Analysts, Inc. (www.strategyr.com). The Asia-Pacific region represents the fastest growing market with a projected CAGR of 4.4% over the analysis period. By chemical type, acrylic adhesives are one of the fastest growing segments worldwide [14].