Glue is everywhere. You see it in your home, office, and even in huge buildings. In simple words, glue is what holds things together. It is a substance that bonds materials. Adhesives are another name for glues. They are essential in our daily lives and many industries.
The History of Glue
Early humans used natural adhesives. The evidence of these marks are present in the form of cave paintings. They mostly used resins from trees. Ancient civilizations like Egyptians, Greeks, and Romans also used glue. They used to use animal, fish, and plant-based glues such as collagen, beeswax, and tar. So these were early forms of glue. You can learn more about glue history from Aleene’s Learn All About Glue’s History and Interesting Facts.
In the Middle Ages, fish-based glues were common. Later, rubber-based adhesives in the 18th century invented. The Industrial Revolution brought synthetic adhesives, marking a significant shift. The modern era, particularly the 1930s and 1940s with the rapid growth of the chemical and plastic industry and the demands of World War II, saw the development of specialized adhesives like neoprenes, epoxies, and acrylonitriles, as explained by ScienceABC – What Is Glue Made Of?. Post-WWII, these glues became widely available, leading to the creation of waterproof glues and even adhesives for space shuttles.
Polyvinyl acetate (PVA) glue, a common type today, was discovered by Fritz Klatte in 1912, with details provided by Vinyl acetate – American Chemical Society. Hermann Staudinger rediscovered PVA in 1924, a story told by The Story of the Birth of New Products: KURALON and PVA – Kuraray. The first PVA-based glue for general use was introduced in 1947.
Key Components of Glue
Glue is made of several key components that work together. The main parts are:
Adhesive Agent
This is the core ingredient that makes glue stick, and it can be natural or synthetic. Glues – Do-It-Yourself Products Fact Sheet: To assess the risks for the consumer – NCBI and Loyal – How Glue is Made: Understanding the Adhesive Ingredients and Process provide further explanation.
Solvents
What they are: Solvents are liquids. In simple words, they are like water in paint.
What they do: You will see solvents dissolve the sticky part of the glue. This makes glue runny. Runny glue is easy to spread and use.
Examples: Water is a common solvent in glue. Think of school glue, it is often water-based. But, some glues use stronger solvents. Acetone and toluene are organic solvents. These are used in stronger glues.
Additives
What they are: Additives are extra things put in glue. This point is noticeable. They are not the main sticky part.
What they do: Additives help glue work better. They can make glue last longer. They can also make it stronger or more flexible. It depends on what the glue needs to do.
Fillers
What they are: Fillers are like powder added to glue. Examples are talc, calcium carbonate, and silica. These are like very fine sand or powder.
What they do: You will see fillers do a few things. First, they can make glue cheaper to make. Second, they can change how glue works. They might make it thicker or stronger in some ways.
Resins
What they are: Resins are special substances. This point is important. They are different from the main sticky agent.
What they do: Resins are added to make glue stickier and stronger. They boost the adhesive strength. So, you see, resins are like strength boosters for glue.
Preservatives
What they are: Preservatives are things that keep glue fresh. Think of food preservatives that keep food from spoiling.
What they do: Preservatives help glue last longer in the bottle. They stop glue from going bad or drying out too fast in the container. They extend the shelf life.
Moisturizers
What they are: Moisturizers are substances that control water. You will see them in skin creams too.
What they do: In glue, moisturizers control how fast glue dries. They can slow down drying. This gives you more time to position things before the glue sets hard.
Other additives like stabilizers, plasticizers, and thickening agents can add elasticity and aid in curing. Polymers, large molecules crucial in modern adhesives (both synthetic and natural), are highlighted by Adhesive | Definition, Types, Uses, Materials, & Facts – Britannica.
Types of Glue Based on Origin: Natural vs. Synthetic
Glue types can be categorized as natural or synthetic.
Natural Glues
Natural glues come from nature. So the basic point is, they are not man-made. You will see they are from plants and animals.
Animal-Based Glues
Source: Animal glues come from collagen. This point is noticeable. Collagen is in animal parts. It is in hides, bones, and tissues.
Manufacturing: Next thing is, to get collagen, they boil animal parts. Then, they clean it up. This makes it pure for glue.
Types: You will see different types of animal glues. Hide glue and bone glue are types. Fish glue is another type. Fish glue includes isinglass and rabbit-skin glue. Keratin glues and gelatin glues are also from animals.
Properties: This point is important. Animal glues stick strongly. But, you can undo them. They are reversible. They also mix with water, so they are water-soluble.
Uses: Animal glues are used in woodworking. Bookbinding also uses them. Art work repairs use animal glues too. Cabinet makers and musical instrument makers use them. They are also used in cloth making and for sealing glass. Animal glues are even used as glue-size for painting prep.
Plant-Based Glues
Source: Plant glues come from starches. So, you see, starches are from plants like rice and wheat. Corn and potatoes also have starches. Natural gums and plant resins are also used.
Manufacturing: Next thing is, to make plant glue, they take starches from plants. Then, they make them into pastes.
Types: You will see different plant glues. Starch glues and dextrin glues are types. Natural gums are also plant-based. Gum arabic, agar, and algin are natural gums. Tree resins are also plant glues.
Properties: This point is noticeable. Plant glues are often safe, non-toxic. They are usually made with water, so they are water-based.
Uses: Plant glues are used for food boxes, food packaging. Wallpaper also uses plant glues. Cardboard boxes, envelopes, and labels use them. For crafts and school work, plant glues are common.
Synthetic Glues
Synthetic glues are man-made. This point is noticeable. They are made to work in different ways. So, you see, they changed how we use glue today.
PVA (Polyvinyl Acetate) Glue
Composition: So the basic point is, PVA glue is made of polyvinyl acetate. It is like a milky liquid. It has water in it. Sometimes, it may have alcohol or other things to keep it fresh or make it thicker.
Manufacturing: Next thing is, to make PVA glue, they take vinyl acetate bits. Then, they mix them in water to join together. This joining process is called polymerization.
Properties: You will see PVA glue as white school glue. It is water-based, so it is easy to clean. It is also non-toxic, which is good for kids. When it dries, it bends a little. It is simple to use and works well for many things. It is a type of plastic polymer that melts when heated.
Uses: PVA glue is for paper and wood. Kids use it for crafts. You can use it at home and school. Paper mache, a type of art, also uses PVA glue.
Epoxy Glue
Composition: Epoxy glue is different. It has two parts. You need to mix them to use it. One part is called epoxide resin. It is made from chemicals. The other part is a hardener.
Manufacturing: This point is important. To make epoxy glue work, you mix the resin and hardener. When you mix them, a chemical change happens. This change makes the glue hard and strong.
Properties: You will see epoxy glue is very strong. It lasts long and is tough. It does not bend easily. It is a two-part glue. You must mix both parts to make it work.
Uses: Epoxy glue is for big jobs. Construction workers use it. Car repair shops use it. It can stick metal, plastic, and ceramics. For heavy things, epoxy glue is good. Electronics and even space jobs use epoxy glue because it is so strong.
Cyanoacrylate (Super Glue)
Composition: Super glue is also synthetic. It is made of cyanoacrylate. Ethyl cyanoacrylate is a common type. It is a liquid form.
Manufacturing: Next thing is, to make super glue, they take cyanoacrylate bits. Then, they join them together in a process called polymerization.
Properties: This point is noticeable. Super glue works very fast. It sticks right away when it touches a little water in the air. But, it can break easily if you bend it. It is a one-part glue. You use it straight from the bottle.
Uses: Super glue is for quick fixes. For small things, it is useful. It can stick metal, plastic, and ceramics quickly.
Polyurethane Glue
Composition: Polyurethane glue is another type. It is made of polyurethane prepolymers. It is a type of liquid plastic.
Properties: You will see polyurethane glue is bendy but strong. It gets hard when it meets air moisture. It is moisture-cured, meaning it uses moisture from the air to set.
Uses: Construction and woodworking use polyurethane glue. It is also used for machines and musical instruments. Packaging also uses this type of glue.
Other Synthetic Glues
So, you see, there are many other synthetic glues. You will see contact cements, which stick when they touch. Hot-melt glues melt when hot and set when cool. Pressure-sensitive glues stick when you press them, like stickers. UV-cured glues need special light to set. Silicone resins are like rubbery glues. There are also silyl modified polymers, polyvinyl alcohol, PVC, PVCE, and polyvinylpyrrolidone. Epoxy putty is like clay epoxy glue. Polyamide adhesives and rubber-based adhesives are also synthetic glues.
How Glue Works?
This point is important: how does glue actually work? In simple words, glue sticks things together because of a few ways it acts.
Adhesion Mechanisms
So, the basic point is, glue uses different ways to stick. These are called adhesion mechanisms.
Adsorption Theory
Next thing is, think about surfaces touching. Adsorption theory is about glue and surface meeting. Imagine two flat surfaces coming together very closely. Forces between atoms, called valence forces, help them stick a little. This is like a very light stickiness just from touching.
Mechanical Adhesion
You will see that surfaces are not perfectly smooth. Mechanical adhesion is about glue filling in tiny gaps. Think of glue going into small spaces and pores on surfaces. When glue hardens in these spaces, it makes a physical lock. It is like puzzle pieces fitting together. This creates a strong hold.
Diffusion Theory
This point is noticeable. Sometimes, glue and the thing you are gluing mix a little. Diffusion theory says molecules from glue and material can mix at the joining area. Imagine sugar dissolving in water. At the point where glue meets material, some molecules mix. This mixing makes a bond.
Chemisorption
This point is important. Sometimes glue makes real chemical links. Chemisorption is when glue and the material form chemical bonds. It is like a strong handshake, not just touching. These chemical bonds are very strong and hard to break.
Electrostatic Attraction
You will see another way glue can stick. Electrostatic attraction is like magnets. Imagine tiny charges in molecules. Glue and materials can have opposite charges. These opposite charges attract each other, like magnets sticking. This attraction helps in bonding.
Factors Affecting Bond Strength
So, you see, how strong glue sticks depends on a few things.
The Adhesive itself
Some glues are just stronger than others. Think about epoxy versus school glue. Epoxy is much stronger because of its chemical makeup.
The Material being glued
Glue sticks to some materials better. For example, wood glue works great on wood. But it may not work as well on very smooth plastic.
The Surface
Rough surfaces are often better for glue. Glue can grip into rough areas. Clean surfaces are also key. Oil or dirt can stop glue from sticking well. So, you should clean surfaces before gluing.
The Interphase Composition
This is about the area where glue and material meet. How well glue flows into the surface and how it interacts there matters a lot for bond strength.
Cohesion vs. Adhesion
Simultaneously, two things are working when glue sticks.
Adhesion
This is when glue sticks to other materials. It is glue sticking to the wood, paper, or plastic you are using.
Cohesion
This is when glue sticks to itself. It is the glue molecules holding onto each other inside the glue layer.
So the basic point is, both adhesion and cohesion are needed for glue to work well. Adhesion makes glue grab onto surfaces. Cohesion keeps the glue itself strong.
Glue Industry and Domestic Applications
You will see glue used in many ways. In simple words, glue is helpful everywhere. From home tasks to big industries, glue is important. Its many uses make it key in daily life and special jobs.
Household and Everyday Uses
So, you see, glue is very useful at home for many repairs. For example, you can use wood glue for fixing a broken chair leg. Or, use PVA glue for mending a torn book cover. DIY fans use glue for making paper crafts or putting together scrapbooks. You will see glue in stationery too.
Glue sticks help in sealing envelopes. Liquid glues are good for attaching labels in offices or schools. Furniture assembly also needs glue. When you put together furniture, glue makes joints strong. From small fixes to fun projects, household glue is always useful.
Industrial Applications
Next thing is, glue is not just for homes. It is also vital for industries.
Construction
Construction work uses strong glues. Installing subflooring uses glue to stop squeaking and make it stable. Affixing moldings uses glue for a neat look. Laminating beams makes them stronger with glue. Prefab buildings use glue to join panels. Woodworkers use glue a lot. They use it for making furniture and building cabinets. Even for floors, glue helps in securing tiles or wood.
Automotive
In car making, glue is replacing screws. This point is important. Glue makes cars lighter and stronger. Bonding windshields to cars uses glue to make them safe and watertight. Putting interior panels in cars uses glue for a smooth finish. Glue also helps in joining car body parts to make them light. Sensors in cars are also secured with glue.
Packaging
Packaging needs glue to work well. Sealing cardboard boxes uses glue fast in factories. Labeling products uses sticky glue labels for everything we buy. For food, food packaging uses safe glues. Even for fragile items, special glue helps in making safe packaging.
Aerospace and Electronics
Aerospace and electronics need very strong glue. Joining aircraft panels uses special glue to make planes strong. Satellites need glue that works in space, even in cold or hot areas. In electronics, glue attaches tiny chips to boards. This makes computers and phones work. Covering electronic parts with epoxy glue keeps them safe from water.
Medical
This point is noticeable. Even doctors use glue. Surgery uses fibrin glue to help in cuts. Adhesive bandages are simple medical glues we all use for small cuts. Scientists are finding new ways to use glue inside the body for fixing tissues.
Other Industries
Simultaneously, glue helps in many other jobs. Bookbinding uses glue to hold pages and covers together. Furniture makers use glue for cloth parts and decorations. Textile industry uses glue in clothes. Even making paper uses glue in the process.
Safety Precautions to Use Glue
Handle glues with care
So, you see, glue is not always harmless. Some glues have chemicals. You need to be careful when you use them.
VOCs in some glues
Next thing is, some glues have VOCs. VOCs mean volatile organic compounds. In simple words, these are chemicals that can go into the air. You can’t see them, but you can breathe them in. Some synthetic glues have VOCs.
Ensure ventilation
You will see if you use glues with VOCs, you need fresh air. Ventilation means having good airflow. Open windows when you are using these glues. If you are in a workshop, make sure the fans are on. Good air helps to take away the VOCs so you don’t breathe too much of them.
Avoid skin and eye contact
This point is noticeable. Glue can irritate your skin or eyes. Try not to get glue on your skin. If you do, wash it off with water right away. Especially, keep glue away from your eyes. If glue gets in your eyes, wash them with lots of water and see a doctor.
Read labels
So the basic point is, always read the glue label. Labels tell you if the glue has VOCs. Labels also give you safety tips on how to use the glue safely. Follow what the label says to stay safe.
Use gloves
You will see for some glues, it is good to use gloves. Gloves stop glue from touching your skin. If you are using strong glues or glues with VOCs, gloves are a good idea.
Work in a well-ventilated area
Simultaneously, not just opening windows, but work in a space where air moves freely. This is extra important when you are using a lot of glue or using it for a long time. Fresh air is your friend when using glues with chemicals.
How to make DIY Glue
You can even make your own glue. This point is noticeable. It is fun and easy to do at home, even if you are just starting out.
Homemade Natural Glue Recipes
So, the basic point is, you can use simple things from your kitchen to make glue. Here are two easy recipes.
Flour and Water Paste
This is the simplest glue you can make. You will see it uses just two things.
- Ingredients:
- Flour (all-purpose flour works fine) – about 1/4 cup
- Water – about 1/2 cup
- Instructions:
- Get a small bowl.
- Put the flour in the bowl.
- Slowly add water, a little at a time.
- Mix it well as you add water. You want to make it smooth, like a thick paste. If it is too thick, add a tiny bit more water. If it is too runny, add a little more flour.
- Keep mixing until there are no lumps. It should look like smooth, white paste.
- Beginner Tips:
- Use cold water. It mixes better with flour at first.
- Add water slowly to avoid lumps.
- Mix really well. Lumps will make your glue weak.
- This glue is best to use right away. It does not keep for long.
Cornstarch and Vinegar Glue
Next thing is, this glue is a little stronger than flour paste. It uses cornstarch and vinegar.
- Ingredients:
- Cornstarch – 1 tablespoon
- Water – 1/4 cup
- White vinegar – 1 teaspoon
- Instructions:
- Get a small saucepan. You will need to heat this on the stove.
- Put cornstarch and water in the saucepan.
- Mix them together until smooth. Make sure there are no lumps of cornstarch.
- Turn on the stove to low heat.
- Cook the mix, stirring all the time. It will start to thicken up.
- Keep stirring until it looks like a thick, clear gel. This might take a few minutes.
- Take it off the heat.
- Stir in the vinegar. This helps to keep it longer and makes it stick better.
- Let it cool down completely before using.
- Beginner Tips:
- Keep the heat low. You don’t want to burn the cornstarch.
- Stir constantly while heating. This stops it from sticking to the pan and clumping.
- Let it cool fully. It will get thicker as it cools.
- Store this glue in a closed jar in the fridge if you are not using it all at once. It will last a bit longer than flour paste.
Conclusion
Glue is a complex substance made from diverse materials, from natural collagen to synthetic polymers, with a long history and wide range of uses. It continues to evolve, with future innovations promising even better adhesives, ensuring its essential role.
Jiuju Tech Strong Adhesives and Epoxies
Jiuju Tech makes different kinds of adhesives and epoxies. In simple words, they make things that stick really well. If you are looking for glue for your projects, Jiuju Tech is worth considering. You will see we have glues for different materials and different jobs. Whether you are working with wood, metal, plastic, or something else, Jiuju has a glue for you.
