The conventional properties of ink mainly refer to physical properties and printing adaptability. The physical properties mainly include the stability of the ink,
Tape fastness of ink, composite strength, resistance to cooking performance. Printing adaptability is mainly the printing stability of ink printing, shallow screen transfer, fog plate and anti-sticking performance.
Ink routine performance testing equipment and materials
Charn Viscosity Cup, stopwatch, scraper Fineness Meter, type tape, scraper rod, various printing substrates (Bopp\Pet\NY\Cpp\Pe), Shimadzu cooking test machine, heat sealing machine, thousand-type compound machine , small printing test machine, experimental version plus over dot
Test methods and instructions for routine physical properties and printing properties of inks
1#, Charne Cup Viscosity Determination Test the original viscosity of blue water-based gravure plastic ink, measured by Charne cup
2#, Ink Stability Observation Experiment Ink precipitation investigation is mainly to investigate whether the ink is precipitated, and the occurrence of adverse phenomena such as rough scraping fineness detection fineness change
3#, Determination of ink dilution rate In order to reduce the viscosity of the ink to the viscosity suitable for printing, the printing factory will add a certain amount of diluent. After adding the diluent, use a Charn cup to measure the ratio of the added diluent to the original ink when the ink viscosity of the diluted ink is in seconds. The diluent for water-based gravure plastic ink is distilled water and ethanol, and the diluent for solvent-based ink is composed of a good solvent for the main resin and an auxiliary solvent.
4#, Determination of ink printing stability Measure the state of the ink and the stability of various properties when the diluted ink is printed for a long time. For example, whether the ink is thicker, whether there are a large number of bubbles, whether the hue, viscosity, etc. have changed.
5#~7#, the tape fastness of each printing substrate of the ink is measured. After the ink is diluted, it is coated on the film with a steel wire bar. The solvent-based diluted ink is coated on the film with a steel wire bar. When the film is completely dry, the tape firmness of the ink is tested. Spend. The adhesive tape adopts the company's standard adhesive tape, and it is judged by examining the extent to which the ink is pulled from the substrate by the adhesive tape.
8#~9#, the water-boiling resistance test mainly tests the water-based gravure plastic composite ink’s water-boiling performance, the water-boiling condition is generally 1°C, and the water-boiling time is one minute. First, ink is printed on the printing film, and then compounded with glue and heat-sealing film through the composite process. After curing, it is made into packaging bags. During the test, boil the composite film according to the boiling conditions and take it out to see whether the ink is delaminated and whether the peel strength of the two-layer film at the ink is reduced.
10#~12#, the retort resistance test mainly tests the retort performance of water-based plastic composite ink, the retort conditions are 121°C, 30~45 minutes, and the pressure of the sealed retort is 5 atmospheres. The glue used is a cooking-resistant two-component aliphatic hydrocarbon polyurethane glue, and the composite structure is generally a substrate with better temperature resistance, such as cooking-resistant CPP film, NY film and aluminum foil, etc.
13#, the content resistance performance test mainly examines the film printed with water-based plastic ink, after compounding the bag, it contains various contents and seals it. Then carry out tests on various conditions of use such as resistance to steaming and cooking. Observe the damage of the bag, generally to see if the ink layer on the film is separated from the film, and whether there is a tunnel phenomenon. If it is separated or has a tunnel phenomenon, it means that the ink after bag making has poor retort resistance and high pressure resistance. , can not meet the requirements of food packaging cooking. By using water, edible oil, and edible vinegar to simulate the contents of acid and oil in the experiment
14#~15#, Blocking anti-adhesive was tested mainly to investigate the drying performance of water-based plastic ink. That is, whether the printing and winding can be carried out normally. If the ink sticks to the back of the plastic film after printing and winding, the printed matter will be scrapped and unnecessary losses will be caused. Its performance is measured in the laboratory by coating a plastic film with a 4# steel wire rod. After it is completely dry, cover it with the back of the same film and measure it with an industrial adhesive back Tester. The pressure of the instrument is adjusted to 5 kg. Take it out after 24 hours in a constant temperature box at 45°C to see if the ink layer is adhered to the back of the same film. If so, it means that the ink has poor anti-sticking performance. The sticking performance of water-based ink is related to the drying speed and printing speed of the ink. Since water-based gravure plastic ink uses a large amount of water as a solvent, its drying speed is very slow, and it is easy to cause sticking due to poor drying. Therefore, the printing of water-based plastic ink is generally at a low speed, and the gravure shallow screen can meet the requirements of normal printing.
16#~20#, color concentration test, shallow screen layer printing expressiveness test After the shallow screen layer experimental plate is printed on the printing machine, observe the expressiveness of the shallow screen and layer of the printed matter. Fog plate performance test After the printing machine has been printing for a long time, observe whether there is any ink stain on the non-graphic part of the printing plate due to unclean scraping.
Table 4.1 The performance parameters of the water-based gravure plastic ink made by the formula and the traditional solvent ink are compared in Table 4.2
Performance Experimental Results and Discussion
The detailed performance is shown in Table 4.2 above
It can be seen from the table that the original viscosity and anti-sedimentation performance of the ink are equivalent to the traditional solvent-based ink, which fully guarantees the storage stability requirements of the ink.
The tape fastness on each base material and the water boiling resistance, retort resistance performance and content resistance performance of the corresponding materials after compounding have also reached the performance indicators of traditional solvent inks.
Blocking、印刷色浓度、浅网层次印刷表现力、雾版性能,等以上测试主要是考察水性塑料油墨的印刷性能,由于水性凹版塑料复合油墨较溶剂性塑料复合油墨的原始粘度较低,水性油墨的颜料含量要高于溶剂性油墨,所以稀释油墨的色浓度远高于溶剂性油墨,这给水性油墨的浅版化提供了有利的条件,因为即使油墨浅版也能达到塑料油墨相同的色浓度,这给水性油墨干燥带来了较大的方便,同时水性油墨也因此具有很好的浅网转移性能。但是水性塑料凹版油墨的实地印刷较溶剂性油墨要差,这与溶剂“水”有很大的关系。“水”对塑料表面的润湿能力较溶剂要差,同时润滑能力也比具有粘滞性的溶剂要差,所以在凹版油墨后调整阶段需要补加一定量的蜡润滑剂聚乙烯蜡滑爽乳液一和成膜助剂来提高油墨的润滑性降低油墨的极性,这就可以减少刮刀和版辊的损伤和提高油墨的流平。总体来说此水墨的各项印刷适性均优于或达到了传统溶剂油墨的要求。
21#,是说明水性凹版塑料复合油墨的干燥速度要比溶剂性油墨要慢的多,水性油墨的干燥不仅要降低印刷速度,而且还要提高印刷机烘道的长度,温度和风量。溶剂性油墨烘道的长度一般要1米左右,温度为55℃上下,水性凹版塑料油墨的烘道要2米以上,温度也要提高一些。同时在印刷时为了提高印刷速度和流平性能,还需要在水溶剂中添加部分乙醇作为稀释剂来印刷。
In short, through the research on water-based gravure blue ink, it can be seen from Table 4.2 that water-based gravure plastic composite ink can completely replace solvent-based composite plastic ink in terms of printing strength, but the printing speed of gravure water-based plastic ink There is still room for improvement, which requires the improvement of printing equipment and the support of social policies.
