what is the sticky stuff on tape?

The sticky substance on tape is called adhesive. Adhesive is a material or substance that is applied to one surface or side of the tape to make it stick to other surfaces when pressure is applied. The primary purpose of the adhesive on tape is to bond the tape to various surfaces, allowing it to adhere securely.

The specific composition of the adhesive can vary depending on the type of tape and its intended use. Different types of tape may use different types of adhesives to achieve specific properties. For example:

1. Pressure-Sensitive Adhesives (PSAs): Most tapes, including standard adhesive tapes like masking tape, duct tape, and packaging tape, use pressure-sensitive adhesives. PSAs are designed to adhere when pressure is applied and can bond to a wide range of surfaces, including paper, plastic, glass, and metal.

2. Rubber-Based Adhesives: Some tapes, such as electrical tape, may use rubber-based adhesives. Rubber adhesives offer good flexibility and can provide a strong bond.

3. Acrylic-Based Adhesives: Clear tapes and some medical tapes may use acrylic-based adhesives. These adhesives are known for their transparency, durability, and resistance to yellowing over time.

4. Silicone-Based Adhesives: Certain specialty tapes, such as high-temperature Kapton tape or some medical-grade tapes, may use silicone-based adhesives. These adhesives are known for their high-temperature resistance and are often used in applications that require durability at elevated temperatures.

The adhesive on tape is carefully formulated to balance properties like tackiness, adhesion strength, durability, and the ability to release cleanly when the tape is removed. Different types of tape may have adhesive formulations optimized for their specific applications and requirements.

It's important to note that not all adhesives are the same, and their properties can vary widely. When selecting tape for a particular task, it's essential to consider the type of adhesive used and its compatibility with the surfaces and conditions where the tape will be applied.