Shrinkage of packaging and printing ink film for flow ping bad and one of the fault occurred. After printing ink, wet ink film in leveling process in a small round after retraction, exposing bare their content materials (bottom) or on a ink layer. Produce shrinkage is the main reason of the printing ink film of the upper part and the surface tension of the different. Some people think that: a wet ink film can be regarded as a double up liquid ink film. In the film process, when the upper wet ink film below the surface tension of the wet ink film of surface tension, happened porosity, and this is because that the relationship between the material wet printing. Sometimes happen this phenomenon in was about to, the wet ink film lost liquidity and happened to inhibit the shrinkage happens. For example in some gravure or Indian offset printing operations, as the temperature rise wet ink film, and liquidity, may cause the second craters.

In theory: remedial measures is to improve the flow of wet ink film, flow ping sex. Surface tension of the ink should not only low, and that the printing material wettability also better. Because the upper wet ink film and wet ink film below the interface of the difference of tension of existence, in the packaging and printing, the system the surface tension of the drop, the printing ink will develop into a complete the cloth ink film. This might have shrinkage of fault, the specific methods: (1) in the printing ink appropriate to join flow ping agent; (2) with low surface tension of solvents; (3) to their surfaces wetting processing (such as printing with solvents before printing material surface that will wipe clean); (4) control the environment of printing work temperature and humidity; (5) choose appropriate explanation agent; 6 reduce printing ink printing and the surface tension between carrier, printing ink and carrier has good wet sex the riser and cause not formed between material surface tension of gradient); 7 solvent evaporation speed adjustment, reduce the viscosity, improve the liquidity of ink, extend the flow flat time; 8) in the packaging and printing ink ink film surface to form a very thin layer of single molecule to provide stability and uniform surface tension.

In order to the correct choice of printing ink the shrinkage of the agent, the following the introduction of shrinkage agent choice.

Solvent class: generally refers to the mixture of high boiling point solvents, is not only a kind of good solvent and pigment good moisturizer (because the solvent evaporation and make the ink (film) body for the dissolution of the sex becomes poor and produce shrinkage, or the baking Indian offset printing inks produce such shortcomings, boiling mark blister).

Colophony kind: generally have vinegar butyl cellulose, especially the compatibility of limited type gather the shrinkage of acrylate resin. Its dosage for acrylic acid resin 1% ~ 1.5%, 0.5% ~ 1% of epoxy resin, polyester resin around 1%.

Organic silicone kind of its function in addition to prevent shrinkage and flow ping, anti-uplift color hair flower, defoaming action. For example XH204 domestic water silicone oil in water-soluble acrylic the printing ink will help promote the flow of printing ink flow, add gentle role.

In addition to the above the shrinkage of the agent, surfactant of polymer and no silicon of fluorine surfactant, it to prevent the ink film of porosity, and improve flow ping and improve printing (graphic) ink film gloss and very effective.

To prevent the packaging and printing ink ink film is to improve the shrinkage of ink in the packaging and printing packaging decoration effect of the important measures. Using different prevent shrinkage, flow ping agent aims to improve printing high print quality, make its printing (surface ink film) grade get extension.

Although they breed type many, but its use also has a limit. Sometimes even improper use or improper dosage, not only it is difficult to meet the proper role, and sometimes bring side effects.

Many years of practice shows: before using, deal with different varieties, dosage strictly screening and test, for the best varieties and the most appropriate dosage. In addition to the contrast test choice by batch more scientific process flow, and even included in the application process for printing add method and so on. Only in this way can we improve our country packaging and printing products product quality, to the practice of the more abundant accumulation theoretical knowledge.