Personal safety when working with epoxy resins and isocyanates, 3. udgave, 1. oplag, 2019

S LI H N IO IT ED

3. EDITION

G EN

3. EDITION

Get ready to work with epoxy and isocyanates.

Personal Safety When Working with Epoxy and Isocyanate covers everything worth knowing about: • What is epoxy and isocyanates, and where are they used?

• Which health risks are associated with the substances?

• Rules regarding labelling of products – and how to understand this information.

• Personal protective equipment and its use, including how to correctly put on and remove the equipment.

• How to protect your surroundings.

• Carrying out the work and waste management.

• First aid.

• Safety culture.

The book is specifically targeted for the mandatory training course “Personal Safety when Working with Epoxy and Isocyanates” which is both a labour market training course and a mandatory course in several vocational education programmes.

The book includes tests, quizzes and practical exercises.

ISBN 978-87-571-2988-5

9 788757 129885

Personal Safety When Working with Epoxy and Isocyanate

• The legislation and regulation of the area, including Danish Working Environment Authority guidelines.

Personal Safet y When Working with

epoxy and isocyanatE

praxis.dk

varenr. 101011-1

Praxis – Erhvervsskolernes Forlag

9 788757 12988 5

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Personal Safety When Working with Epoxy and Isocyanate

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Personal Safety when Working with Epoxy Resins and Isocyanate Š Praxis, 2019 3th edition, 2019, 1th printing, 2019 1th edition released 2010 Publishing Editor: Michael B. Hansen, mh@praxis.dk Translation: Marie Pedersen Desktop Publishing: Strunge Grafik Cover: Strunge Grafik Photos: Videncenter for Allergi, ICM ArSiMa A/S, Ejnar Als Brix, Tech College Aalborg, Colourbox Cover photo: Colourbox The book is typed with: Minion Pro Order Number, print edition: 101011-1 Varenummer, e-udgave: 101011-9+ The print edition: ISBN 978-87-571-2988-5 The book is printed on Amber Graphic 120 g Cover: Carta Elega 230 g Print: PNB Print Printed in Latvia 2019

All rights reserved under copyright law. Copying from this book may only take place at institutions that have a copying agreement with Copydan Writing (Tekst & Node), and only within the scope of the agreement.

See more at www.copydan.dk Praxis praxis.dk webshop.praxis.dk

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Content Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Mandatory Training Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Course Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Requirements to the Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Prohibition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.

Product Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Historical Background of Epoxy and Isocyanates . . . . . . . . . . . . . 12 Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Chemical Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.

Health Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Epoxy Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Products Containing Isocyanates . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Protecting Yourself . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Eczema (Dermatitis) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Organic Solvents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Objective 4

4.

Legislation and Regulation of the Working Environment . . . . 33 The Working Environment Act . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Executive Orders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 WEA Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Regulations on Working with Epoxy and Isocyanates . . . . . . . . . 34 Working Environment Authority . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Sector Working Environment Councils . . . . . . . . . . . . . . . . . . . . . 36 Hierarchy of Controls/Prevention Ladder . . . . . . . . . . . . . . . . . . . 37 Substitution Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Rules for Spray Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Other Regulations of the Working Environment . . . . . . . . . . . . . 41 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Objective 1, 5 and 6

5.

Labelling of and Information about Substances and Materials 43 Labels on Products containing Epoxy and Isocyanates . . . . . . . . 44 Substances and Mixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 REACH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 CLP Regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Emballering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Storage of Hazardous Substances and Materials . . . . . . . . . . . . . . 52 Safe Storage of Toxic Substances . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Safety Data Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Workplace Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Limit Values for Substances and Materials . . . . . . . . . . . . . . . . . . . 64 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Objective 4

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6.

Protect Yourself . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Use of Personal Protective Equipment . . . . . . . . . . . . . . . . . . . . . . . 70 Selecting Personal Protective Equipment . . . . . . . . . . . . . . . . . . . . 70 Gloves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Eye Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 Respiratory Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Working Clothes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Personal Hygiene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Objective 2 and 3

7.

Protect Your Surroundings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Legislation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Signposting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Personal Hygiene – Protecting your Surroundings . . . . . . . . . . . 95 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Objective 7 and 8

8.

Carrying Out the Work and Waste Management . . . . . . . . . . . . 97 Carrying out the Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Waste management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 Work-related Injuries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Objective 2, 9 and 11

9.

First Aid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 General First Aid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 Emergency Response Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 Drops and Splashes in Eyes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Drops and Stains on the Skin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Skin Corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Shortness of Breath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

Objective 10

10.

Safety Culture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 What is Safety Culture? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 Developing the Safety Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 Behavior and Attitudes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 Safe Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

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Preface Epoxy and isocyanates possess extraordinary properties in terms of strengths and durability, which is why they are used in many contexts in different products and production processes. However, they belong to the category of hazardous substances and materials, for which there are a number of legal regulations and safety rules. To be able to work with epoxy and isocyanates professionally in a safe and responsible way that protects the safety of yourself and your surroundings, a two-day course (AMU (Labour Market Training Course) course no. 47942) is required. This is a legal requirement.

This book is specifically targeted for the abovementioned course, and therefore the book carries the same title as the training course: Personal Safety when Working with Epoxy and Isocyanates This book covers: • What is epoxy and isocyanates, and where are they used?

• Which health risks are associated with the substances?

• The legislation and regulation of the area, including Danish Working Environment Authority guidelines.

• Rules regarding labelling of products – and how to understand this information.

• Personal protective equipment and its use, including how to correctly put on and remove the equipment.

• How to protect your surroundings.

• Carrying out the work and waste management.

• First aid.

• Safety culture.

Preface 16th A lot has happened since the 15th edition of this book was released in 2014. Some of the relevant legislation, regulations and guidelines have been changed and the book has been updated accordingly. However, we have deliberately toned down the references to specific legislation, and instead made endnote references for those who want to read further about the specific law or guideline.

The idea behind this is that students should stay focused on what matters to the safety aspect of the work and not be disturbed by paragraphs and numbers.

Deadlines for various transitional arrangements have been passed, which means that the book, for example, no longer describes the old orange hazard pictograms, or the R and S statements.

An important change since the 15th edition is that the action-oriented learning objectives for the course from The Educational Secretariat for Industry have been tightened and clarified. The objectives and intentions of the new course are dealt with in Chapter 1. One of the points is that there should be more focus on practical skills.

The book provides the theoretical basis to be used in the course, while the practical exercises are organized and carried out at the various course locations.

As a new feature, we have included various tests and suggestions for practical exercises in the chapters where this is relevant. “Test yourself exercises” give students an opportunity to check if they have understood the most important points from the course.

The practical exercises should support the focus on the practical skills. Both tests/exercises and practical exercises are intended as a catalog of ideas, which the individual teacher can choose from to complement his or her own instruction material in consideration of the time frame and the specific group of students.

The publisher is very pleased to receive suggestions from the book’s users regarding tests and practical exercises that would be useful to include in future editions of this book.

In addition to being a useful reference book, which is nice to have at hand, even after the course is over, it is now also a personal workbook. It is therefore a good idea if the student writes their name on, for example, the inside of the book cover.

Preface

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The publisher would like to thank everyone who contributed to this book, and especially Ejnar Als Brix, TECHCOLLEGE, who undertook the sizeable task of giving the book a much needed update.

Praxis October 2019

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preface

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ยง 1.

Mandatory Training Course

ยง

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Before you are allowed to work with epoxy and isocyanates, you must have completed and passed a course. This applies to everyone – both apprentices, unskilled and skilled workers. The rules are first and foremost put in place to protect you and your surroundings when working with hazardus substances and materials.

Course Objectives

The course will ensure that you are able to perform the work on epoxy and isocyanates in a healthy and safety manner with regards to yourself and your surroundings.

They are all expressions of knowledge, skills and competences that you must take away with you when this course is over.

Objective 1:

Objective 2:

Objective 3:

Objective 4: Objective 5:

Objective 6:

Objective 7: Objective 8:

Objective 9: Objective 10:

Objective 11:

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1 . M a n d ato r y

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The Danish board of education for the manufacturing industry, Industrial Educations, has formulated the 11 action-oriented objectives for the course “Personal Safety when Working with Epoxy and Isocyanates” (course no. 47942).

You must be able to ensure that work on epoxy and isocyanates follows the Danish Working Environment Authority’s guidelines for work with substances and materials and work with epoxy and isocyanates, until the substances and materials have cured and the danger of harmful effects has stopped.

You must be able to choose and correctly use the right protective equipment and possibly other safety precautions by reading workplace instructions, safety data sheets and any code numbers.

You must be able to put on, remove and use personal protective equipment, including gloves, respiratory protective equipment and protective suits in such a way that your skin, hands and surroundings are not contaminated with epoxy and isocyanates, and so that airways are not exposed to aerosols, gases and vapors.

You must be able to identify health risks related to carrying out the work.

You must be familiar with the general prevention principles of the working environment legislation, including insight into the substitution principle and its application.

You must be able to identify prohibited work situations, including knowledge of the prohibition on spraying epoxy and isocyanates outside spray booths and the like.

You must be able to ensure that the necessary warning signs are installed and if necessary other signposting while performing the tasks.

You must be able to ensure that employees other than those working with the substances and materials, do not stay so close to work that they may be exposed to health hazards.

You must be able to take hygiene precautions and welfare measures correctly in connection with the work performed.

You must be able to provide first aid and perform emergency management if a person comes into contact with epoxy and isocyanates, this includes using emergency shower and eye-flushing equipment.

You must be able to handle hazardous waste, including disposing used packaging, gloves and suits in a safe, healthy and environmentally responsible way, so that no one can get residues of not fully cured epoxy and isocyanates on skin and hands.

Training Course

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Requirements to the Course The epoxy and isocyanate course must contain both theory and practical exercises.

You must be able to deal with both large and small quantities of epoxy resins and isocyanates, regardless of your educational and professional background. This means that even though you know from the start that you must work with epoxy in connection with the production of wind turbine blades, you must also have the necessary knowledge about, for example, bonding car windows with isocyanates, and vice versa.

The course must contain all the subjects necessary for you to acquire the qualifications required in the Danish Working Environment Authority’s Executive Order on Work with Substances and Materials, Appendix 3. [1-1] In the theoretical part of the course, it is important that you learn how to read instructions for use, safety data sheets and MAL codes, so that you can read the product’s degree of danger and make the correct choices in terms of protective equipment and any other safety precautions based on the product’s properties.

oving protective equipment, so neither you nor others come into contact with the substances and materials. It must also include exercises in work site arrangement, product handling as well as first aid and emergency management.

Prohibition Some people are prohibited from working with epoxy and isocyanates: [1-2] • Persons with eczema or epoxy allergy must not work with substances and materials containing epoxy.

• Persons suffering from asthma or eczema, as well as persons with chronic lung disorders or skin or respiratory allergies to isocyanates, must not work with isocyanate-containing substances and materials.

• Persons with severe sweating of the hands (hyperhidrosis manuum) must not work with epoxy or isocyanate-containing substances and materials.

You must also not work with epoxy and isocyanates before 18 years of age, unless you have an apprenticeship.

In the practical part of the course, exercises should be included in the correct putting on and rem-

1 . M a n d ato r y

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Training Course

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Exercises Most likely the following questions have been clarified, before you started this course. Therefore, you should know the correct answers to the questionnaire below.

We recommend that you write your name on the inside of the book cover.

Writing your answers in the book, makes it your private workbook.

Are any of the following persons permitted to work with epoxy and / or isocyanates? Tick yes or no.

Questions

YES

NO

Persons suffering from ezcema Persons suffering from epoxy allergy Persons suffering from asthma Persons suffering from chronic lung disorder Persons with a skin allergy towards isocyanates Persons with respiratory allergies towards isocyantes Persons suffering from severe sweating of the hands Persons under 18 years of age, and without an apprenticeship Persons, who can answer no to all eight questions, are permitted to work with products containing epoxy and isocyanates upon completing this safety course.

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1 . M a n d ato r y

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Training Course

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2.

Product Knowledge

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Historical Background of Epoxy and Isocyanates Plastic products were first produced in 1862. They were based on plant matter; cellulose fibers from cotton were treated with nitric acid thus forming cellulose nitrate or celluloid. The combination of cellulose and nitric acid resulted in a transparent and ductile, but at the same time highly flammable, material.

In 1909 a new raw material was discovered, coal tar. This was utilized in the manufacturing of Bakelite, which was used for insulation of electrical installations, cameras and telephones.

In the 1930s, the manufacturing of plastics from crude oil began.

Over time new plastic materials emerged, and in the 1950s new types of synthetic plastics with greater mechanical strength and stability were introduced, including epoxy resins.

An isocyanate was first produced synthetically in 1848. In 1937, the German chemical group IG Farben developed a method for synthetically manufacturing polyurethane plastics (shortened PUR or PU) using isocyanates and it was within this area, isocyanates were introduced to the manufacturing industry in the 1950s.

Today polyurethanes containing isocyanates are a vast group of materials.

Usage Isocyanate-containing products and epoxy products have become widely used in the trades and industries. The products are especially used within the building sector, the metal industry, the plastics industry, and by electronic manufacturers. The products are used in material production, casting, installation and bonding as well as for surface treatment in construction works and for installation of machinery and inventory. Products can be configured to achieve specific qualities.

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2.

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Epoxy Epoxy products are used for the following purposes: • Anti-corrosive primers • Manufacturing of wind turbine blades • Car paint • Floor paint/surface treatment • Fillers • Adhesives • Joint filler for concrete and tiles • Concrete vapor barriers • Insulation of electrical wiring and circuits • Orthopedic prostheses • Dental bridges • Furniture • Grips on tools • Jewelry Epoxy products are used because they are moldable, insulating and light.

Epoxy Exposure Epoxy exposure may occur in various ways, such as: • Contamination of the working environment • No or unsuitable protective equipment • Airborne exposure • Evaporation • Heating up • Spray (epoxy-based paint or gel coat) • Dust from grinding • Spills • Accidents • Drops There may be both primary and secondary exposure to epoxy resins and hardeners.

It is important to note that epoxy can be allergenic both in connection with mixing, application and machining, e.g. grinding of the non-fully cured substance.

In some cases, it will be necessary to protect the respiratory system when handling and using epoxy resins and hardeners containing organic and reactive solvents.

Product Knowledge

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Epoxy – examples of usage Epoxy adhesive (e.g. Araldite)

Wind turbine blades

Grips on tools

Anti-corrosive primers (e.g. for ships)

Car paint

Allergic reactions in the form of eczema due to contact with epoxy resin typically occurs on hands and forearms, whereas facial eczema typically occurs via evaporation from a hardener. Allergy can occur after just a single exposure and a single drop may be enough to trigger it. Nevertheless, the more frequently you are exposed, the higher the risk of developing an allergy.

Isocyanates Products containing isocyanates are for instance used in: • Paints and lacquers • Manufacturing of wind turbine blades • Adhesives • Joint filler • Insulation • Floor coating • Imbedding of electronics • Alternatives to rubber • Soft and rigid foams

Products with isocyanates are used in widely different industries, due to their technical and economical properties: • The auto industry • The metal industry • The plastics industry • The construction industry • Wood and furniture industries • The electronics industry • The paint and coating industries • The printing industry – inks and laminating • The household appliance industry • The health sector – fast hardening plastics instead of plaster Exposure to Isocyanates Exposure to isocyanates occurs during work processes where polyurethane products are made or used. This is referred to as primary exposure.

Common polyurethane products are foam rubber, foam insulation, joint filler, adhesives, paints and coatings. Employees in industries producing foam rubber, furniture, paints and coatings, car paint,

2.

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Product Knowledge

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Isocyanates – examples of usage Insulation for district heating pipes

Spray foam insulation Imbedding of electronics

Printing ink and lamination

Auto glass bonding

and in the construction industry, are often exposed to isocyanates.

Exposure to isocyanates can also occur during work processes in which polyurethane products are heated to temperatures above 150 °C. This is referred to as secondary exposure.

Adhesives

Welders, auto aligners, foundry workers (bonding material in casting sand), workers in the electronics industry (welding circuit boards) thus may be exposed to isocyanates.

The heating of other plastics such as urea- and phenol formaldehyde, Bakelite and urethane oils may release isocyanate compounds.

This will typically occur when welding, soldering and other types of hot work are performed on surfaces treated with polyurethane products (paints, coatings, adhesives etc.)

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Product Knowledge

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Chemical Composition An isocyanate or epoxy product consists of a resin part and a hardener or accelerator. This is referred to as a 2-component system.

In addition to the pure resin and hardener, epoxy products consist of a variety of ancillary substances.

It is also possible to generate resins, which consist of long, heavy molecules with a molecular weight greater than or equal to 700 (≥700). These resins may be of high viscosity/thin.

Epoxy compounds, especially the low-molecular type, easily react with biological materials, and may thus be hazardous to health.

These can be mixed into the hardener or resin but can also be added immediately prior to use – a 3-component system.

Epoxy resins with an average molecular weight ≤ 700 are called low-molecular (= major health risk) Epoxy resins with a molecular weight ≥ 700 are called high-molecular (=health risk, especially when the monomers content ≥ 1 %).

The uncured epoxy consists of molecular chains, which have an epoxy group at both ends. A simple epoxy group consists of two carbon atoms and an oxygen atom.

At an average molecular weight of 380, the epoxy resin is liquid at room temperature. An epoxy resin at an average molecular weight of 1,000 will appear firm at room temperature.

Epoxy resins have a molecular weight between 340 and 200,000.

Chemical composition, epoxy group

When these are mixed, a chemical reaction will occur and a plastic is formed. This is called a polymer. The mixture will set and harden. The original molecular composition determines how hard the mixture becomes. You can achieve materials that are as hard as metal, or flexible enough to use as soles on shoes.

This process is called a hardening or curing (polymerization).

Epoxy Resins An epoxy resin is defined as a molecule with more than one epoxy group, and which can harden into a useable plastic material.

The most frequently applied epoxy resins consist of various diglycidyl ethers. They are generated from epichlorohydrin and bisphenol A. This type of resin is designated as Bisphenol A diglycidyl ether (DGEBA), molecular formula C21H24O4.

By varying the ratio between bisphenol A and diglycidyl ether, it is possible to generate resins which consist of short, light molecules with a low molecular weight (<700), which may appear liquid.

In practice an epoxy resin will be a mixture and the molecular weight given is the average molecular weight.

Hardeners The hardener is necessary to achieve a functional product. The choice of hardener determines the properties of the final product.

Epoxy groups can react with various types of hardeners, which may affect the speed of the hardening/curing process, ranging from minutes to days. The hardener also determines whether it is a cold curing or hot curing epoxy system.

Since the hardener is used in large measures, it has a great effect on the properties of the cured epoxy.

Hardeners are divided into these categories: • Acid anhydride • Aliphatic and aromatic polyamides • Catalytic hardeners For each epoxy base, chemical calculations and tests are made, in order to determine the correct mixing ratio with a chosen hardener.

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It is therefore very important to always choose the proper materials and to observe the mixing ratio specified by the manufacturer. Otherwise, unintended reactions may occur, or the product may not harden at all.

Epoxy system may also have added accelerators (catalysts) to aid the hardening process. These are often amines or phenols.

Dissolving Agents Dissolving agents are added to make the resin, or the composite of resin and hardener, adequately liquid for practical handling.

Like in standard dissolving agents, which evaporate during the curing process, hydrocarbons, alcohols, esters etc. are used.

Reactive dissolving agents, which are used in the curing process itself and thereby remains (chemically combined) in the finished product, particularly uses low molecular epoxy composites.

A number of these reactive dissolving agents evaporate easily and are associated with high health risks. The lowest molecular resins, and therefore the most liquid ones, can be utilized without any form of dissolving agents or may be dispersed in water.

Other Additives Other than hardeners and dissolving agents, epoxy systems may contain pigments, fillers and other additives.

Products Containing Isocyanates Isocyanates is a generic term for chemical substances with one or more functional isocyanate groups (NCO) in their molecular structure.

The resin is a polyol, which chemically is an alcohol. Polyols have a high viscosity and are therefore not very hazardous to the health. Pure polyols are not hazardous to the health.

Isocyanates are aggressive chemicals, which can react with water, alcohols, amines, etc.

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Isocyanates pose the greatest health risk associated with the manufacturing of polyurethane products.

Isocyanates in the form of fumes, mists (aerosols), or (unreacted) drops of PUR spray mixtures, are harmful when inhaled. Even very small quantities irritate the nose, throat, or lungs.

The hardener is a diisocyanate or a related substance. Diisocyanates have two functional isocyanate groups and are used as a starting point for the formation of polyurethanes (often called monomeric isocyanates).

Common diisocyanates (hardeners): • MDI – Methylene diphenyl diisocyanate (harmful to health) • TDI – Toluene diisocyanate (very toxic) • HDI – Hexamethylene diisocyanate (toxic) • IPDI – Isophorone diisocyanate (toxic) One reason that TDI is classified as very toxic is the fact that when heated (to approx. +150 °C) it will release isocyanates. This is called secondary exposure.

TDI (2,4- and 2,8- toluene diisocyanate) is listed on the Danish Working Environment Authority’s list of substances that are considered carcinogenic.

Polyurethane – PUR Many polyurethane products (PUR) are now available for filling, grouting and bonding. These are the so-called prepolymeric polyurethanes, in which polyol and isocyanate are combined in a container. The chemical reaction only starts when the substances come out of the container and come into contact with the humidity of the air. Here it is important to ensure the necessary ventilation and protect the respiratory system.

Polyurethane is formed when an isocyanate reacts with an artificial resin Polyurethanes may appear as: • Solid thermoplastics • Foamed plastics, that may be rigid, half-rigid, or flexible • Thermoplastic elastomers

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• • • •

Adhesives Joint filler Surface treatment/coating Elastic fibers

Polyurethane is produced when an isocyanate reacts with a resin. Polyurethane foam (foamed plastics) consists of three things: • Polyols, which are the resin part.

• Hardener, generally an isocyanate, that causes the mass to harden quickly.

• Various additives, that among other things, are used to ensure the durability of the foam.

Foamed plastics can be produced via chemical foaming, which occurs when the combined substances release carbon dioxide.

Foamed plastics are typically used in mattresses or furniture.

Other Additives In paints and others coating products, various other additives can be found: • Dissolving agents • Plasticizers • Wetting agents • Matting agents • Emulsifiers • Anti-degradants • Anti-skin agents • Anti-sediment agents • Coloring agents and pigments

The chemical substance carbon dioxide (CO2) which is a greenhouse or atmospheric gas.

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EXERCISES 1. Write 5 examples of the use of epoxy-containing products. Several industries must be represented. Searching the Internet is allowed.

The task can be solved in groups of 2-3 people:

2. Write 5 examples of the use of isocyanate-containing products. Several industries must be represented. Searching the Internet is allowed.

The task can be solved in groups of 2-3 people:

_______________________________________

_______________________________________

_______________________________________

_______________________________________

_______________________________________

_______________________________________

_______________________________________

_______________________________________

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3. Which of these two epoxy compounds reacts most easily with biological material, such as your skin, and is therefore a major health hazard?

(Tick)

■ Low molecular weight epoxy resin (average molecular weight ≤ 700).

■ High molecular weight epoxy resin (average molecular weight ≥ 700).

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S LI H N IO IT ED

3. EDITION

G EN

3. EDITION

Get ready to work with epoxy and isocyanates.

Personal Safety When Working with Epoxy and Isocyanate covers everything worth knowing about: • What is epoxy and isocyanates, and where are they used?

• Which health risks are associated with the substances?

• Rules regarding labelling of products – and how to understand this information.

• Personal protective equipment and its use, including how to correctly put on and remove the equipment.

• How to protect your surroundings.

• Carrying out the work and waste management.

• First aid.

• Safety culture.

The book is specifically targeted for the mandatory training course “Personal Safety when Working with Epoxy and Isocyanates” which is both a labour market training course and a mandatory course in several vocational education programmes.

The book includes tests, quizzes and practical exercises.

ISBN 978-87-571-2988-5

9 788757 129885

Personal Safety When Working with Epoxy and Isocyanate

• The legislation and regulation of the area, including Danish Working Environment Authority guidelines.

Personal Safet y When Working with

epoxy and isocyanatE

praxis.dk

varenr. 101011-1

Praxis – Erhvervsskolernes Forlag

9 788757 12988 5

Epoxy-e_Omslag.indd 1

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