The Problem of Material Selection in High-Temperature Cooked Intaglio Compound Ink Formula(I)

1 Introduction

China's flexible packaging technology has developed rapidly and its level has been continuously improved. The flexible packaging materials produced are of various styles, of which the composite flexible packaging material has become one of the more mature domestic main packaging materials. For example, PET, BOPP, VMPET, VMCPP, PE, CPP, and AL are used as film substrates, and the trend toward flexible packaging is toward high barrier properties and high-temperature cooking resistance. In particular, external flexible packaging materials such as foods and pharmaceuticals require high-temperature anti-virus, environmental protection, and other high performance. This requires a combination of printing inks suitable for high-temperature cooking resistance to meet such high-performance conditions. As a result, high-temperature cooking-intaglio plastic composite ink came into being.

2 High temperature resistant cooking gravure plastic composite

Ink and its characteristics:

The high temperature resistant cooking gravure plastic compound ink uses the relevant chloroacetic resin and special polyurethane as the linking material, and adds a series of special auxiliaries and organic solvents, together with organic pigments with high temperature resistance, uniformly stirring, dispersing and grinding, and adhering. Paired with color. It is suitable for printing in low-speed to high-speed plastic film, and the substrate is generally a composite plastic film of PET, BOPP, NYLON (nylon) and aluminized film. The printed products can be used in ordinary composite processes, and are more suitable for high-temperature cooking compound processes. The ink film solvent residues are low, odorless, non-toxic, environmentally safe and can be used for the packaging of food and medicine, and meet the sanitary requirements.

High temperature resistant cooking gravure plastic composite ink has the following characteristics:

1 High attachment fastness, suitable for a variety of printing films;

2 Low viscosity, good leveling property, large solid content, bright color, high color concentration, good dot reproducibility, suitable for multi-color printing;

3 Excellent printability, good ink transferability, suitable for different machine speeds and depths;

4 The printed products can be cooked at high temperature. Usually the single-component can be boiled (90～100)°C in high temperature cooking and (100～120)°C in high-temperature cooking. The addition of 3%～4% curing agent in two-component printing can improve the ink. Printed products of high temperature performance, film properties, printability, composite fastness.

3 recipe design points

3.1 Selection of Binder

Experience ink viscosity, fluidity, drying, transferability, gloss and fixing properties are mainly determined by the link material, and its characteristics such as acid and alkali resistance, high temperature resistance, etc., are also inseparable with the properties of the link material. Therefore, the focus of the development of high-temperature cooking-resistant intaglio plastic compound ink formulations lies in the research and selection of related materials.

At present, it can be applied to the high-temperature resistant intaglio plastic composite ink formulation of the linking material, and the ink body of the improved ink is only the chloroacetic resin and the polyurethane resin. Chloro-acetic acid resin is a copolymer of vinyl chloride (VC) and vinyl acetate (VAC), which is essentially a dry paint base. A film is formed after the volatile organic solvent contained in the formula is evaporated. In the high temperature resistant cooking gravure plastic compound ink formula, generally used after the film has a high tenacity, durable softness, abrasion resistance, low water swell, low permeability, high temperature cooking and other characteristics of the vinegar vinegar Resin. Since gravure inks are used on a variety of plastic film substrates, the surface of these plastic films is smooth. Therefore, when selecting this type of chloroacetic resin in the ink formulation, it should be considered that the chloroacetic resin molecules have carboxyl groups (—COOH). A class of chlorocyanic resins therefore exhibit excellent adhesion on smooth-surfaced substrates, especially for substrates such as aluminum foil. Therefore, the carboxyl-containing vinyl chloride and vinyl acetate as well as the dimer of dicarboxylic acid (ie, the ternary chloroacetic resin) are one of the indispensable linking materials in the high-temperature cooking-retarding plastic composite ink formulation. Ketones, esters, and chlorinated hydrocarbons are commonly used solvents for carboxyl-containing chloroacetic resins. The ternary chloro-acetate resins used in inks are generally formulated with a mixed solvent of butanone, isopropyl alcohol, ethyl acetate, and toluene. Chloro-acetate resin solution with a solid content of about 20% is stored in a barrel or storage tank for use.

Polyurethane plastic (PU), the chemical name is polyurethane foam, which is a foam plastic obtained by reacting a polyurethane monomer resin solution with a polyether polyol or a polyester polyol through a catalyst and other additives, according to raw materials. The components are different, divided into two kinds of polyether and polyester, and there are soft and hard points. The polyurethane resin solution used in the ink formulation is only the monomer composition of the above-mentioned polyurethane plastic (PU), which is modified and compounded with organic solvents such as ketones and esters, and the solid content is generally about 30%, which is colorless or shallow. Yellow transparent viscous liquid. As a binder for inks, the polyurethane resin liquids generally contain -NCO groups, and the degree of polymerization of the molecules is small, but the molecular structure is complicated and there are many kinds of them. Among them, simple monomers have toluene diisocyanate (TDI), two. Phenyl methane diisocyanate (MDI), polyphenyl poly methyl polyisocyanate (PAPI), trihydroxy polyether (glycerol polyether). Polyurethane adhesives for inks sold in the market are modified polyurethane monomer resin liquids, and some important molecular functional groups are introduced to provide various excellent properties after film formation. Especially with some curing agents (the main component is polyether or polyester polyol compound) can produce ink film with different properties, such as having soft, high tensile strength, good oil and solvent resistance , Excellent insulation and barrier properties; especially high temperature resistance, when designing high-temperature cooking-resistant intaglio plastic compound ink formulations, consideration should be given to the selection of such polyurethane resin solution as the main linking agent.

When choosing a polyurethane resin liquid for inks, the required ink has excellent adhesion with the plastic film, the ink film has good resistance to heat and boiling resistance, good solvent release, and a small amount of residual, and the pigment is Good wetness, high gloss properties. Polyurethane resin solutions for inks currently on the market are mainly composed of polyurethane compounds, isopropyl alcohol, butanone, toluene, and the like. The appearance is colorless or light yellow transparent viscous liquid, and the solid content is generally 25 % to 35%; the amount added in the ink formulation is usually 35% to 45%.