Hey there! As a supplier of tissue machines, I often get asked about the sizing process in a tissue machine. It's a crucial part of making high - quality tissue products, so I thought I'd break it down for you.
What is Sizing in a Tissue Machine?
Sizing in a tissue machine is all about adding certain substances to the paper pulp to modify the properties of the final tissue product. It's like giving the tissue its unique features, whether it's making it more absorbent, stronger, or more resistant to water.
There are two main types of sizing: internal sizing and surface sizing. Let's start with internal sizing.
Internal Sizing
Internal sizing is done right when the pulp is being prepared. We add sizing agents to the pulp mixture. These agents are usually chemicals that react with the cellulose fibers in the pulp. For example, rosin - based sizing agents are quite common. When added to the pulp, they form a kind of hydrophobic layer around the fibers. This layer helps to reduce the penetration of water into the tissue.
Why is this important? Well, think about kitchen towels. You want them to be able to soak up spills, but you also don't want the water to just pass right through. With internal sizing, the kitchen towels can hold the water better. If you're interested in a Kitchen Towel Tissue Machine, we've got some great options that are designed to work well with different sizing processes.
Another type of internal sizing agent is alkyl ketene dimer (AKD) or alkenyl succinic anhydride (ASA). These are synthetic sizing agents that are very effective in making the tissue more water - resistant. They work by reacting with the hydroxyl groups on the cellulose fibers, creating a stable bond that repels water.
Surface Sizing
Surface sizing, on the other hand, is done after the paper has been formed on the tissue machine. It's like a finishing touch. We apply a thin layer of sizing solution on the surface of the tissue. This can be done using a size press or a spraying system.
The main purpose of surface sizing is to improve the surface properties of the tissue. It can make the tissue smoother, which is great for products like facial tissues. You don't want a rough - feeling facial tissue rubbing against your skin. A Facial Tissue Making Machine from us can produce tissues that are perfect for surface sizing applications.
Surface sizing also helps to increase the strength of the tissue. The sizing solution can fill in the gaps between the fibers on the surface, making the tissue more resistant to tearing. And if you want to add some extra features like ink - receptivity for printing on the tissue, surface sizing can do that too.
The Sizing Process Step by Step
Let's take a closer look at how the sizing process actually happens in a tissue machine.
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Pulp Preparation (for Internal Sizing)
- First, we start with the raw materials, which are usually wood pulp or recycled paper. The pulp is mixed with water to form a slurry.
- Then, the sizing agents are added to the slurry. The amount of sizing agent depends on the desired properties of the final tissue product. For example, if we want a highly water - resistant tissue, we'll add more of the sizing agent.
- The pulp and sizing agent mixture is then stirred thoroughly to ensure that the sizing agent is evenly distributed among the fibers.
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Paper Formation
- The pulp slurry is then fed onto the wire section of the tissue machine. Here, the water starts to drain away, and the fibers begin to form a web.
- As the web moves along the machine, more water is removed through pressing and drying processes.
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Surface Sizing (if applicable)
- After the paper has been formed and partially dried, it moves to the size press or spraying area.
- The sizing solution, which can be a starch - based solution or a synthetic polymer solution, is applied to the surface of the tissue.
- The tissue then goes through another drying process to remove the water from the sizing solution and set the sizing on the surface.
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Final Processing
- Once the sizing is complete, the tissue goes through further processing steps like calendering. Calendering is a process where the tissue is passed between rollers to make it smoother and more uniform in thickness.
- Finally, the tissue is wound onto reels or cut into the desired sizes for packaging.
Factors Affecting the Sizing Process
There are several factors that can affect the sizing process in a tissue machine.
Sizing Agent Selection
The type of sizing agent you choose is crucial. Different sizing agents have different properties and work better for different types of tissue products. For example, if you're making hand towels, you might want to use a sizing agent that gives the towel a good balance of absorbency and strength. Check out our Hand Towel Tissue Machine and we can help you select the right sizing agent for your needs.
pH of the Pulp
The pH of the pulp can have a big impact on the effectiveness of the sizing process. Most sizing agents work best within a certain pH range. For example, rosin - based sizing agents usually work best in an acidic environment, while AKD and ASA work better in a neutral to slightly alkaline environment.
Temperature and Drying Conditions
The temperature during the drying process can affect how the sizing agent sets on the tissue. If the temperature is too high, it can cause the sizing agent to break down or evaporate before it has a chance to bond properly with the fibers. On the other hand, if the temperature is too low, the sizing process might take too long, and the tissue might not dry evenly.
Importance of a Well - Executed Sizing Process
A well - executed sizing process is essential for producing high - quality tissue products. It can make the difference between a tissue that falls apart when you use it and a tissue that is strong, absorbent, and has a great feel.
For consumers, a well - sized tissue means a better user experience. Whether it's using a facial tissue to wipe your nose or a kitchen towel to clean up a mess, you want a tissue that performs well.
For manufacturers, a proper sizing process can lead to cost savings. By using the right sizing agents and processes, you can reduce waste, improve production efficiency, and increase the overall quality of your products.
Conclusion
So, that's the sizing process in a tissue machine in a nutshell. It's a complex but important part of making tissue products. As a tissue machine supplier, we're here to help you every step of the way. Whether you're just starting out in the tissue manufacturing business or you're looking to upgrade your existing equipment, we've got the knowledge and the machines to meet your needs.
If you're interested in learning more about our tissue machines or the sizing process, don't hesitate to reach out. We'd love to have a chat with you about your specific requirements and how we can help you produce top - notch tissue products. Let's start a conversation and see how we can work together to take your tissue manufacturing to the next level.
References
- "Tissue Paper Handbook" by James C. Paulapuro
- "Paper and Board Sizing" by K. G. A. P. van den Akker