Flexo printing 1000 questions (517-534)

517. What matters should be paid attention to when preparing ink using Dongfeng brand adhesive?
Answer: The following matters should be noted when using the Dongfeng brand adhesive for ink formulation.
(1) Because the cross-linking agent FH, EH, H has high adsorption, when used with the reactive dyes, 4% finishing agent CHD (pH adjustment with 1% ammonia water) or 6% cycloethylene urea (DMEV) is applied. ) (solid content 50%) instead.
(2) If anti-inking or anti-printing reactive dyes are used in the ink formulation, the amount of ammonium sulfate should be determined according to the degree of difficulty of the anti-dyeing when ammonium sulfate is added to the finishing agent CHD, generally increasing to 3% to 7%. .
(3) Adding acetic acid to pigments can increase the permeability, but when printing with reactive dyes, non-volatile organic acids should be used instead of acetic acid. When the two colors of ink are in contact, penetrant JFC is used instead of acetic acid, and the amount is 0.5%~
1.0%.
(4) In order to increase the brilliance, fluorescent paste is usually added to the ink.

518. What is the reference recipe and conditions of use for the Luhua 106 adhesive printing?
Answer: Refer to Table 1 for the reference formula for the Luhua Label 106 adhesive printing.
Use conditions: pH value of 6.5 ~ 7.0; solid content of 38% ± 2%; fixing temperature of 150 °C; baking time of 3 minutes.

519. What is the reference recipe and conditions of use for the DECORPHOTO® 107 adhesive printing?
A: The reference formula for the stencil card 107 adhesive printing is shown in Table 2.
Conditions of Use: The adhesive is a general-purpose type, and no thickener is required for printing; the fixing temperature is 150°C; and the baking time is 3 minutes.

520. What is the reference formula and application conditions for the low-fire oil adhesive printing?
Answer: See Table 3 for the reference formula for the low flame oil adhesive printing.
Conditions of use: Can be used for rotary screen and manual screen printing, better for large area printing; sensitive to electrolyte; fixing temperature 150 °C; baking time 3 minutes.

521. What are the advantages and disadvantages of adding cross-linking agents to printing adhesives?
A: The printing adhesives are mostly linear thermoplastic resins, and the abrasion resistance and wash fastness are not good enough. Therefore, it is often necessary to add thermosetting resins and urea, precondensates of melamine and formaldehyde, or condensates of epichlorohydrin and ethylenediamine. Conduct cross-linking. The addition of a thermosetting resin can reduce the swelling of the film in water, which can increase the fastness, but at the same time it can also make the film hard and brittle. If the two resins are mixed directly during use, the stability of the binder will be reduced. Therefore, a resin having an active functional group may be used as a binder to introduce a hydroxyl group, an aldehyde group, a carboxyl group, an amide group, and an amino group into its molecular chain. As well as their substitutions, they can cross-link with a cross-linking agent having a multifunctional group to form a network-structured high polymer and improve fastness.

522. Commonly used monomers for printing adhesives can be classified according to their nature.
Answer: The monomers selected for printing adhesives can be classified into four types: hard monomers, soft monomers, reactive monomers, and reactive crosslinkable monomers.

523. How to use different brands of adhesive when printing fabric?
Answer: Comprehensive consideration should be given to fabric varieties, printing methods, process conditions, coating color, pattern size and cost, feel, fastness requirements, and objects to be used. Reasonable selection of different brands of adhesives.

524. What is cross-linking, degree of cross-linking, and cross-linking agent?
A: Cross-linking refers to the process in which a linear structure molecule contains a multifunctional group, and functions as a multifunctional group or high-energy radiation to form a bulk-structured molecule with a bridge bond.
The physical quantity indicating the degree of crosslinking is referred to as the degree of crosslinking.
The cross-linking agent refers to a substance that can act as a bridging member during the polycondensation of linear structure molecules and bonds the groups in the molecules to each other to form an insoluble mesh body.

525. What is a non-crosslinking adhesive?
A: Non-crosslinking adhesives are linear polymer materials. There are no groups in the molecule that can crosslink, and they cannot be cross-linked during film formation. Such as Dongfeng brand adhesives, 202 rubber pulp BA, etc. are non-cross-linked adhesives.

526. What is a diplomatic linkage adhesive?
A: The molecular structure of the diplomatic linkage adhesive contains carboxyl groups, amide groups, amino groups, etc., which can cross-link with the additional cross-linker functional groups, and react with external cross-linkers to form a network structure during film formation. Film, can improve the print color fastness.
527. What is a self-crosslinking adhesive?
Answer: The adhesive containing the self-crosslinking group of the macromolecule bond in the molecule is called a self-crosslinking adhesive, such as a 107 screen printing adhesive.

528. What is the effect of adding cross-linking agent to printing paste?
A: There are two main functions: one is to further improve the fastness of the adhesive; the other is to lower the film forming temperature of the adhesive.

529. How to choose cross-linking agent for fabric printing?
A: The choice of cross-linking agent should be based on the printing formulation, processing conditions, composition of the adhesive and production conditions and other conditions comprehensive consideration, a reasonable choice, the general amount of cross-linking agent EH is 0.5% to 2.0%.

530. What are the effects of thickeners in printing inks?
A: The thickener is one of the important components in the printing ink. It has the function of thickening the ink, promoting adhesion and emulsification, and giving the printed fabric a clear outline. The addition of a thickening agent to the printing ink can not only make the color vivid, but also replace the state pulp A containing a large amount of kerosene in the printing paste, thereby reducing the pollution.

531. What is the chemical composition and thickening mechanism of the thickener?
A: The chemical composition of the thickener is mainly a copolymer emulsion of butyl acrylate, styrene, acrylic acid, and methylol acrylamide. The thickening effect is formed by the fact that the carboxyl groups are negative and repel each other in the ionized state.

What is the property and use of 532.870 thickener?
A: 870 thickener PAS is an acrylic acid-based copolymer amine salt, is a white flowable emulsion, pH value of 7.0 ~ 8.0, easy to disperse, thickening ability, with structural viscosity characteristics, added in the printing paste A small amount can reach the required thickness. However, it is sensitive to electrolytes and cannot be mixed with strong acids, otherwise its thickening ability will be significantly reduced.

533. What role do emulsifiers play in printing inks?
A: The addition of an emulsifier to the printing ink can provide a good emulsifying and thickening effect, so that the ink will not be delaminated under long-term storage conditions and prevent the precipitation of pigment particles.

534. What role do diffusion agents play in printing inks?
A: Adding a certain amount of diffusing agent to the printing ink can promote the stability of the slurry. In addition, in the preparation of the adhesive, in order to make it into an aqueous dispersion, a certain amount of a diffusing agent is usually added at a content of 2% to 3% of the solid content.

Source: Coinprint