What is the coating of sublimation paper？
Created on 08.01
The coating on sublimation paper is a specially formulated layer applied to one side of the paper. Its primary purpose is to temporarily hold the liquid sublimation ink after printing, then release nearly all of that ink as a vapor when heat and pressure are applied during the transfer process.
Here's a breakdown of the key components and functions of the coating:
1. Binder: The primary component, usually a modified starch or a synthetic polymer (like PVA - Polyvinyl Alcohol). This forms the base matrix that holds the ink droplets in place on the paper surface after printing.
- Crucial Property: It must form a weak, temporary bond with the ink. This bond is strong enough to keep the ink on the paper while it's handled and dried, but weak enough to completely release the ink vapor when heated during pressing.
2. Release Agents: These are additives designed to facilitate the clean and complete transfer of ink from the paper to the substrate under heat and pressure. They prevent the ink from bonding too strongly to the paper coating itself.
- Goal: Achieve near 100% ink release for maximum color vibrancy and efficiency.
3. Sizing Agents/Barriers: These components control the absorption and spread of the ink droplet when it hits the paper.
- Purpose: They create a slight barrier, preventing the ink from soaking too deeply into the paper fibers. This keeps the ink concentrated near the surface where it can easily vaporize and transfer.
- Benefit: Results in sharper image definition, prevents "bleeding" or feathering of ink dots, and improves color density.
4. Fast-Drying Agents: Help the ink dry quickly on the surface of the paper after printing. This prevents smudging and allows for faster handling and pressing.
5. Absence of Certain Additives: Unlike regular inkjet paper coatings designed to absorb ink permanently (which often contain silica, alumina, or special polymers for dye fixation), sublimation paper coatings deliberately avoid these permanent fixing agents. Permanent fixation on the paper is the opposite of what's needed.
Why is this Coating SO Important?
- High Ink Release: Essential for vibrant, saturated colors on the final product. Poor release leaves ink on the paper, resulting in dull, washed-out transfers.
- Sharp Image Detail: Controls ink spread, preventing bleeding and maintaining fine lines and details.
- Efficiency: Maximizes the amount of ink transferred to the substrate, reducing waste.
- Fast Drying: Improves workflow speed.
- Prevents Ghosting/Sticking: A good release coating minimizes the risk of the paper sticking to the substrate or leaving a faint residue ("ghosting") during transfer.
In essence: The sublimation paper coating acts as a sophisticated temporary parking lot for the liquid ink. It holds the ink precisely where it landed after printing, dries it quickly, and then lets go of virtually all of it instantly when heat turns it into a gas, allowing it to penetrate the target substrate and create a permanent, vibrant image. The specific formulation of binders, release agents, and sizing is what differentiates high-performance sublimation paper from regular paper or even other types of inkjet transfer papers.
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