Introduction
What is glue made of? Many people are curious about this question. Whether you are building furniture, packaging products, or doing school assignments, glue is everywhere. To understand what glue is made of, we first need to look at the different kinds of adhesives. Not all glue is created equal.
From ancient natural sources to today’s synthetic formulas, glue has come a long way, and understanding its composition can help you choose the glue that best suits your needs.
A Brief History of Glue
Before we dive into what is glue made of, let’s take a look at the history of glue. Humans have been gluing things together for thousands of years. The oldest known glue dates back to around 200,000 BC, when people used birch bark tar to glue spearstones to wood. Today, glue is used in a variety of industries. The history of glue is quite fascinating, so let’s quickly review its origins.
Ancient Origins
The earliest evidence of human use of adhesives dates back to 200,000 BC, when Neanderthals began using birch bark tar as an adhesive.
About 5,000-6,000 years ago, the ancient Egyptians and Mesopotamians began using natural adhesives:
- Animal collagen glue: used to make furniture, tools, and tomb construction
- Plant resin glue: used to bond crafts and daily necessities
Classical Era
Ancient Greeks and Romans improved the glue-making process:
- Animal glue: made by boiling animal skins and bones, used in woodworking and artwork
- Egg white glue: used for bonding fine crafts
China developed a unique bonding technology:
- Rice paste glue: widely used in papermaking and book binding.
Middle Ages to 19th Century
Animal glue became the mainstream material for furniture making and bookbinding in Europe.
In the 18th century, the world’s first commercial glue factory appeared in the Netherlands.
In the 19th century, advances in chemical technology enabled people to better control the viscosity and strength of glue, laying the foundation for the emergence of modern synthetic glue.
20th Century–Present
The invention of synthetic polymers during and after WWII revolutionized adhesives.
Example: Polyvinyl acetate (PVA), epoxy resins, cyanoacrylate (super glue)
Today’s glues are formulated for specific industries: from medical adhesives to industrial-grade bonding.
Types of Glue by Composition
When it comes to what is glue made of, it all starts with the base ingredients, and these can vary widely depending on the application. Broadly speaking, adhesives fall into two major categories: natural and synthetic.
Natural glues are derived from animal or plant sources. Synthetic glues, on the other hand, are engineered using modern chemistry to meet specific industrial needs, offering stronger bonds, faster drying times, and greater resistance to heat and moisture. Let’s take a closer look at both types.
Natural Glue
- Animal glue: Made from animal collagen (bone, hide), often used in woodworking and traditional crafts.
- Plant glue: Derived from gum, corn, wheat, or potato starch. Used for paper gluing, labels, and cardboard lamination.
- Casein glue: A protein glue made from milk. Historically used in woodworking and packaging.
- Advantages: biodegradable, renewable, low toxicity
- Limitations: low water resistance, short shelf life, weak adhesion
Synthetic Glue
White glue: The main component is polyvinyl alcohol emulsion, which achieves a bonding effect by drying and forming a film.
All-purpose glue: The main component is cyanoacrylate, which solidifies instantly after contact with water vapor.
Epoxy resin glue: It adopts a two-component formula and forms a high-strength bond through chemical reaction after mixing.
Hot melt glue: The main component is ethylene-vinyl acetate copolymer (EVA), which is heated and melted and then cooled and solidified.
| Aspect | Natural Glue | Synthetic Glue |
| Main Ingredients | Animal collagen, casein, starch, plant resins | (PVA), epoxy, polyurethane, cyanoacrylate |
| Source | Derived from animals or plants | Made from petroleum-based chemicals |
| Biodegradability | Generally biodegradable | Often non-biodegradable |
| Bond Strength | Moderate, varies by material | High and customizable strength |
| Water Resistance | Poor to moderate | Can be highly water-resistant or waterproof |
| Shelf Life | Shorter, sensitive to storage conditions | Long shelf life, more stable |
| Drying Time | Often slow | Can range from quick |
| Applications | Woodworking, bookbinding, crafts, paper | Construction, packaging, automotive, and medical |
| Environmental Impact | Lower (natural origin, less toxic) | Higher (unless formulated to be eco-friendly) |
How Glue is Made?
Ever wondered how glue is made? It’s a step-by-step process that starts with blending raw materials like polymers and additives, followed by mixing, filtering, and packaging. Strict quality control is implemented throughout the production process to ensure that the performance of each batch of glue is stable and reliable.
1. Raw material preparation
First, we will select high-quality polyvinyl alcohol, resin, and other main raw materials, which determine the viscosity and safety of the glue. All raw materials must be strictly tested to ensure purity without impurities.
2. Mixing and stirring
The raw materials are placed in a large mixing tank, and the mixture is heated and stirred until a uniform and stable formula is formed. This process requires precise control of temperature and time.
3. Filling and cooling
After the glue is accurately injected into the packaging container through the fully automatic filling line, it moves and cools in the water. The water temperature is kept at 15-20℃, and the cooling time is about 5-8 minutes. Ensure that the glue is quickly set and maintained in the best condition.
4. Packaging
Once approved, glue is filled into appropriate containers, bottles, tubes, drums, or bulk tanks. A fully automatic packaging line is used to neatly stack the glue bottles/sticks into boxes. Labels and safety data sheets (SDS) are added.
Applications of Glue
The way glue is formulated directly affects how it performs on different materials. Each type of surface, whether it’s porous like wood or smooth like plastic, requires specific adhesive properties to ensure a strong, lasting bond. Here are some common applications:
1. Wood
Woodworking is one of the oldest and most common applications for glue. In furniture making, cabinetry, construction, and even musical instrument production, adhesives play a critical role in joining wood components together.
Wood glue needs to penetrate the porous grain of the wood to form a strong internal bond. Commonly used adhesives include PVA wood glue and polyurethane glue, both designed for deep penetration and structural strength.
2. Paper and Packaging
Glue is heavily used in the paper industry, particularly in printing, bookbinding, label production, envelope sealing, and packaging.
Since paper is highly absorbent and lightweight, the adhesive must offer quick tack, easy application, and a clean finish.
Common adhesives include dextrin glue, hot melt adhesives, and PVA. These adhesives are typically water-based or thermoplastic, chosen for their fast drying time, non-toxicity, and ease of cleanup.
3. Plastics
Bonding plastic materials presents unique challenges because plastics are often smooth, non-porous, and chemically resistant. As a result, standard adhesives won’t bond effectively.
They require powerful adhesives like cyanoacrylate (super glue) or specialty solvent-based glues that can chemically bond to the surface.
These adhesives are widely used in electronics, consumer goods, plastic models, automotive interiors, and packaging materials.
4. Textiles
In the textile and garment industry, glue is used for bonding fabrics, attaching trims, appliqués, or even assembling shoe components. Adhesives for textiles must be flexible, soft, and able to withstand washing and wear without cracking or peeling.
Common glue types include hot melt adhesives, fast-drying and used for bonding fabric layers or applying embellishments.
Textile glues are especially useful where stitching isn’t possible or when a clean finish is desired.
5. Stationery and Office Supplies
In homes, schools, and offices, glue is a daily necessity. These applications prioritize ease of use, safety, and a mess-free application.
Popular products include glue sticks, solid, twist-up adhesives are ideal for kids and paper crafts. White school glue (PVA) is safe, washable, and perfect for paper, cardboard, and light craft materials.
These glues are designed to be non-toxic, quick-drying, and easy to store, making them suitable for all ages and skill levels.
FAQ
What is hot glue made of？
Basic materials: thermoplastics (such as EVA, polyolefins), melted by heating, solidified by cooling.
Tackifying resin: improves viscosity (such as rosin, petroleum resin).
Wax: adjusts fluidity and softening point.
Additives: plasticizers (increase flexibility), antioxidants (anti-aging), pigments (coloring), etc.
How long does the glue last?
The durability of glue varies greatly. For example, white latex and 502 glue can usually last for several months to several years, while epoxy resin and polyurethane glue can last for more than 5 years or even permanently. The specific lifespan depends on the type of glue, bonding material, environmental conditions, and stress conditions.
How long does it take for glue to dry?
The drying time of glue varies greatly depending on the type:
502 glue: 5-30 seconds for surface drying, 24 hours for complete curing
White latex: 30 minutes for initial fixation, 24 hours for complete hardening
Epoxy resin glue: 5 minutes to 12 hours for initial curing, 24 to 72 hours for maximum strength
Different types of glue have different drying times. If you want to learn more about different types of glue, click 9 Essential Types Of Glues for Everyday Use.
Are horses still used to make glue？
Historically, glue was made from animal collagen found in horses, cattle, and other animals, especially their hooves and bones. But today, most glues are synthetic, made from materials like polyvinyl acetate or epoxy, which are cheaper, more efficient, and consistent in quality. While some specialty animal glues are still used in crafts and restoration, they typically come from cattle or fish, not horses.
Does environmentally friendly glue exist?
There are many environmentally friendly glues available on the market, such as biodegradable glue made from corn starch, non-toxic and odorless water-based glue, and PLA hot melt glue made from plant materials.
While maintaining environmental characteristics, these environmentally friendly glues have greatly improved their performance and can provide customized glue solutions for different industries, such as absorbable suture tape for medical use and low-temperature curing glue for the electronics industry.
How to remove glue residue?
Instant glue: Soften with acetone or a special glue dissolving agent, then wipe.
White latex/paste: Soak in warm water and scrub with soap or alcohol.
Hot melt glue: Scrape off the ice cubes after freezing and becoming brittle, or use a hair dryer to heat and soften, and wipe.
Epoxy resin: Soak in alcohol or white vinegar and polish.
Self-adhesive: Apply wind oil or cooking oil to dissolve and remove.
Conclusion
So, what is glue made of? From ancient animal glues to today’s high-performance synthetics, adhesives have evolved to meet the demands of modern life. Whether you’re a buyer looking for a custom formulation or simply curious about what makes things stick, knowing the basics of glue composition can help you choose the right product for the job—and maybe even appreciate the science behind every bond.
