functions of polyurethane binder in printing ink

The functions of polyurethane resin in inks are as follows:

1. Excellent yellowing resistance.
Polyurethane resin for ink is mainly synthesized from aliphatic polyester and aliphatic isocyanate as the main raw materials during the preparation process. Compared with aromatic polyurethane, it has excellent optical stability, and the film has excellent Yellowing resistance.

2. Excellent adhesion fastness to film substrates.
The molecular segments of the polyurethane binder for ink contain polar groups such as urethane, allophanate, ester bonds, and ether bonds, and are compatible with a variety of polar substrates, PET The polar groups on the surface of plastics such as PA and PA form hydrogen bonds, thereby forming joints with a certain connection strength. After the polyurethane resin is made into ink, it has good adhesion fastness when printed on the surface of polar plastic substrates.

3. Has good affinity and wettability with pigments

Polyurethane resin for ink is generally prepared from polyester or polyether polyol, alicyclic diisocyanate and diamine/diol chain extender. Due to the introduction of urea bonds in PU resin, polyurethane-urea resin (PUU) is formed, which makes it have good dispersion and wetting properties for pigments.

4. Good resin compatibility.
Polyurethane resin for ink has good compatibility with aldehyde-ketone resin, chlorine-vinegar resin, etc., and can be appropriately added to your own process formula according to actual conditions to improve the overall performance of the ink.

5.Excellent film-forming properties

The structure of ink polyurethane resin is different from the polyurethane resin used in other fields. Traditional polyurethane mainly reacts with polyester polyol/polyether polyol and isocyanic acid to form hydroxyl-terminated polyurethane resin. The polar group in the molecular structure is aminomethyl. Mainly acid ester, the molecular cohesion is not enough to meet the film-forming performance requirements of resin for ink. Therefore, polyurethane resin for ink introduces urea group on the basis of traditional polyurethane to greatly improve the cohesive strength and film-forming properties of the resin itself.

6. Good solvent release:

The dissolving effect of organic solvents on resin is to attract solute molecules through the polarity of solvent molecules, which is commonly known as like dissolves. Traditional polyurethane resins have a wide range of compatibility with organic solvents. However, in the process of making inks, in order to adjust the ink flow properties and viscosity, alcoholic organic solvents need to be added. This will greatly reduce the stability of the resin system for traditional polyurethane resins. properties, turbidity, flocculent precipitation and other incompatibility phenomena may occur. However, the polyurethane resin used in ink is miscible with alcohol due to the presence of urea groups, but it should be noted that alcohol solvents are still pseudo-solvents. In the microscopic state, alcohol solvents wrap the polyurethane resin molecules, rather than true solvents due to the polarity of the molecules. Penetrating through the molecule, the ink made of polyurethane resin has good fluidity.

 

Polyurethane resin is a versatile material that can be used in the preparation of gravure printing ink for film. Gravure printing is a method of printing that uses engraved cylinders to transfer ink onto a substrate, and it is commonly used for high-volume printing applications such as packaging and labeling.

as a binder to provide adhesion and durability to the ink. It can also be used to adjust the viscosity and flow properties of the ink, which is important for ensuring consistent print quality and optimal ink transfer to the substrate.

We could provide solvent based polyurethane resin, polyurethane emulsion, acrylic resin, waterborne polyurethane dispersion to meet diversified requirement.