Characteristic selection and application of the mo

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Characteristic selection and application of cooking resistant plastic ink pigments (I)

many kinds of food need to be sterilized at high temperature together with plastic packaging. If the cooking resistance of the ink is poor, there will be apparent color change or fading after high temperature cooking; In order to maintain the normal color of printed plastic bags after high-temperature cooking, it is very important to choose high-temperature cooking resistant plastic ink; The key technology of high temperature cooking of ink is the selection of pigments in ink

high temperature cooking resistance of ink mainly refers to the heat resistance of ink, that is, the degree of color change resistance of ink layer under heating. The heat resistance of plastic ink mainly refers to the heat resistance of packaging in the process of cooking, heat sealing and compounding. The poor heat resistance is mainly manifested in the fading of ink layer, discoloration, unclear graphics and texts, etc. The heat resistance of ink mainly depends on pigment and binder. The heat resistance of binder is poor, and it will change from white to brown after heating. Therefore, the heat resistance of light color ink depends on binder, and the heat resistance of color ink depends on pigment. This paper will take red organic pigment ink as an example to analyze and discuss the heat resistance of ink and the selection of pigment

heat resistance experiment of organic pigments

conduct 20 ° angle deflection axial tension experiment. The cooking resistant plastic ink is composed of binders composed of different resins, colorants and auxiliary agents (such as fillers, wetting agents, viscosity reducers, etc.). Organic pigments are insoluble in water and organic solvents. They are highly dispersed particulate colorants with bright colors, high coloring intensity, good light resistance, weather resistance, heat resistance, solvent resistance, migration resistance and dispersion

in this experiment, four kinds of red pigments were selected as colorants of plastic cooking resistant ink for testing, because red pigments are commonly used in printing inks, and the types of red organic pigments in solvent inks are the most; Moreover, the heat resistance of red pigments is generally divided into four levels, which are bright in color, and even subtle discoloration can be identified

1. experimental pigments and instruments

1) experimental pigments

the four red pigments selected in this experiment are:

① golden red C (yellow red) pigment, pigment index number: p.r.53:1, yellow powder, which is generally produced by c.l.t acid diazo coupling method

② YONGGU red f4r (fr3560) pigment, pigment index number: p.r.8, is a red powder with bright color, good alkali resistance, general sun resistance, poor heat resistance, blue bright red in case of concentrated nitric acid, yellow bright red in case of concentrated sulfuric acid, and no color change in case of sodium hydroxide

③ lisolbo red BK (n53) pigment, pigment index number: p.r.57:1, is a dark red powder with blue light, bright color, high coloring power, insoluble in ethanol, golden red after dissolving in hot water, good acid and alkaline resistance, general sun resistance, heat resistance up to 150 ℃, red in case of concentrated sulfuric acid, magenta precipitation after dilution, brownish red precipitation in case of aqueous solution in case of hydrochloric acid, brown in case of concentrated sodium hydroxide

④ YONGGU red 2B (bright red) pigment, pigment index number: p.r.48:2, purplish red powder, insoluble in water and ethanol, purplish red in case of concentrated sulfuric acid, blue red precipitation after dilution, brownish red in case of concentrated nitric acid, red in case of concentrated sodium hydroxide, good heat resistance

2) main instrument

kgz-1a gloss meter; SM-II sanding machine; Pb203-n electronic balance; Xxqg02 steam sterilizer; XD scraper fineness meter: dmde450 optical coating machine; D-8401 type multifunctional speed regulating agitator

3) experimental raw materials and drugs

resin a solution, resin B solution, DCHP, low molecular wax, 4 kinds of pigments, toluene (analytical pure), butanone (analytical pure)

2. Preparation of experimental ink

first mix the resin a solution, low molecular wax, DCHP, toluene and butanone according to the formula, and stir them for 10 minutes as part a; Then add an appropriate amount of resin B solution and stir it for about 60 minutes as part B, so that all components are mixed evenly

① pour the fully stirred ink into the sand mill for grinding, so that the ground ink has various rheological properties and printability that the ink should have

② put the prepared ink into the sample bottle, seal it tightly, and stick a label for testing

the formula and preparation process used in this test are carried out according to the conventional methods of industrial production ink

the ink prepared with the same quality of raw materials, from large to small, is golden red C, YONGGU red f4r, lisolbo red BK, YONGGU red 2B. Among them, the volume of golden red C ink is about three times that of YONGGU red 2B ink. The prepared YONGGU red 2B ink is very thick and difficult to filter. Therefore, when testing, you should first dilute the YONGGU red 2B ink to an appropriate concentration with solvent

3. preparation of experimental samples and heat resistance test

1) preparation of samples

the prepared ink is printed on PET film, BOPA film and BOPA film treated by ion bombardment respectively. The ink performance test shall be sampled according to the standard requirements. The reference gold for the heat resistance test shall see whether the pull rod swings left and right. It belongs to the ink heat resistance test standard, and 20mm shall be cut × Several pieces of 100mmpet film and BOPA film are standby

2) please pay attention to the following items for pigment heat resistance test content

① dry dry the four pigments at 100 ℃ and 40 minutes respectively, and compare them with the standard sample after cooling to investigate their color changes

② dry the samples of 8 kinds of inks under 5 conditions such as 100 ℃ and 40 minutes, and compare them with the standard samples after cooling. However, if we buy a tensile testing machine with poor quality due to price, we will investigate the color change

③ eight samples of four inks were boiled and boiled with tap water at 100 ℃ and 40 minutes. After cooling, they were compared with the standard samples to investigate the color change, fading and color change of water

4. experimental standard

this experiment is carried out according to the national standard for inspection methods of intaglio plastic ink, including gloss inspection, fineness inspection, initial dryness inspection, adhesion fastness inspection, anti adhesion inspection, color inspection standard and ink fluidity inspection standard

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