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This paper aims to address the problem of uncertain product quality in digital light processing (DLP) three-dimensional (3D) printing, a scheme is proposed to qualitatively estimate whether a layer is printed with the qualified quality or not cured .

A thermochromic pigment whose color fades at 45°C is prepared as the indicator and it is mixed with the resin. A visual surveillance framework is proposed to monitor the visual variation in a period of the entire curing process. The exposure region is divided into 30 × 30 sub-regions; gray-level variation curves (curing curves) in all sub-regions are classified as normal or abnormal and a corresponding printing control strategy is designed to improve the percentage of qualified printed objects.

The temperature variation caused by the releasing reaction heat on the exposure surface is consistent in different regions under the homogenized light intensity. The temperature in depth begins to rise at different times. The temperature in the regions near the light source rises earlier, and that far from the light source rises later. Thus, the color of resin mixed with the thermochromic pigment fades gradually over a period of the entire solidification process. The color variation in the regions with defects of bubbles, insufficient material filling, etc., is much different from that in the normal curing regions.

A temperature-sensitive organic chromatic chemical pigment is prepared to present the visual variation over a period of the entire curing process. A novel 3D printing scheme with visual surveillance is proposed to monitor the layer-wise curing quality and to timely stop the possible unqualified printing resulted from bubbles, insufficient material filling, etc.

Microencapsulated organic thermochromic pigments may have varied industrial applications, such as in windows and greenhouse roofs. Two black coloured commercial microencapsulated pigments from A and B brands are used in this work. The study is conducted with UVA irradiation, and simulation of atmospheric conditions (weathering tester QUV). After a few degradation cycles, the colour of the substrate becomes a yellowish hue, which suggests that chemical degradation of the components of the microcapsule has occurred. Some tests that include DSC are carried out in order to obtain information on the composition of the microcapsules.

Extraction with organic solvents provides several fractions that are analysed by ¹H-NMR and IR. It is concluded that the material of the microcapsules is melamine formaldehyde and two of the core components are probably crystal violet and benzotriazole, which are assumed to act as a UV absorber and promoter of proton transfer. SEM analyses of the pigments before and after degradation show that the microcapsules maintain their shape. A study is also implemented on the effect of adding DABCO to the suspensions of the pigments, which are then irradiated with UV light. A somewhat protecting effect is observed.

This paper aims to demonstrate that, in line with the emerging trend of multifunctional yarn development, cotton yarn can effectively harness renewable solar energy to achieve photothermal conversion and thermochromism. This innovation not only maintains the comfort associated with natural fiber cotton yarn but also enhances its ultraviolet (UV) light resistance.

In this work, 4% zirconium carbide (ZrC) and thermochromic powder were adhered to cotton yarn through polyurethane (PU) by sizing coating method. After sizing, the two cotton yarns are twisted by ring spinning to obtain composite yarns with photothermal conversion and thermochromic functions.

The yarn obtained by cotton/6%PU/8% thermochromic dye single yarn and cotton/6%PU/4% ZrC single yarn composite is the best match. After 5 min of infrared light, the temperature of the composite yarn rose to the maximum, increasing by 36.1°C. The ΔE* value before and after irradiation of infrared lamp is 26.565, which proves that the thermochromic function is good. The yarn dryness unevenness was significantly reduced by 27.2%. The composite yarn has a UPF value of up to 89.22, and its performance characteristics remain stable after 100 minutes of washing.

The composite yarn’s photothermal conversion and thermochromism functions are mutually reinforcing. Using sunlight can simultaneously achieve heating and discoloration effects without consuming additional energy. The cotton yarn used in this application is versatile, and suitable for a wide range of uses including clothing, temperature visualization detection and other scenarios.

Stimulant-sensitive materials exhibit physical or chemical reversible changes in their properties as a result of environmental variables. One of these materials is thermochromic materials. Materials with thermochromic sensitivity change their color with heat exchange. For this reason, it can be used in many different fields such as security inks. Such substances decompose rapidly by being affected by weather conditions. Furthermore, the particle sizes are larger than normal pigments, and therefore, it is difficult to stabilize thermochromic dyes. Because of all these adverse conditions, thermochromic colorants must be protected before use in the ink. This protection is planned to be provided by the microcapsulation technique. The purpose of this study is to determine the thermochromic printing inks that can be stored stably by microcapsulation technique, to protect it from environmental conditions and the determination of printability parameters.

In this study, capsules with a core material of thermochromic dyeing with polyurea formaldehyde (PUF) or poly-phenolmelamine formaldehyde (PMF) shell were synthesized at appropriate pH and temperature using the appropriate solvent and mixing speed. The chemical structure and dimensions of the obtained capsules were examined by ATR-FTIR and scanning electron microscopy, respectively. The produced thermochromic microcapsules were mixed with alkyd resin and mineral oil and screen printing ink was obtained. Printability tests such as surface morphology, color, gloss and light fastness were applied.

As a result, it was determined that PMF is not a suitable encapsulation technique for thermochromic dyes under suitable conditions and eliminates thermochromic property by providing heat stability. It was found that PUF microcapsulation can be used in thermochromic dyestuff encapsulation and does not lose the thermochromic property. It has also been found that PUF microcapsules increase the lightfastness and stability of thermochromic dye ink.

This study provides experimental research on the encapsulation of a thermochromic dye and its use in ink.

Sea‐Nine Biocide ‐ Rohm and Haas Company announced that Sea‐Nine 211 biocide has been registered for use in marine paints by the US Environmental Protection Agency. Sea‐Nine 211 is the first new generation organic biocide to earn this registration.

This paper aims to analyse the tack stability measurement readings of thermochromic offset inks. For this purpose, three reversible leuco-dye formed thermochromic inks were used to evaluate their tack. The used inks differ in their activation temperature, colour, drying mechanism, viscosity and chemical content. Thermochromic offset inks differ from conventional inks in formulation and size of colourants due to the presence of the microcapsules.

Printing inks in offset lithography must have sufficient tack so they can be transported from a reservoir onto the substrate. The ink transfer takes place through the ink splitting by inking rollers, printing plate and blanket transport. An IGT Tackoscope device was used to produce the dynamic readings of ink tack as a function of distribution and splitting time. The data can be used for prediction of the ink press stability under controlled settings, such as temperature.

This research explains the temperature and velocity influence on the tack stability measurement readings of thermochromic inks. It also gives an insight of the chemical compounds that dictate the tack measuring reading results.

Development of new printing inks, such as thermochromic printing inks, may affect the printing of different products. The research was conducted due to a lack of available data for the tack of thermochromic inks.

The Mearl Corporation, New York, NY, announces the introduction of Mearlin (R) Aztec Gold, the newest addition to the company's expanded offering of golden pearlescent luster pigments which now consists of 17 different grades.

A system for wetting down a given amount of pigment without using cumbersome trial‐and‐error methods was recently described by the Montreal and Toronto Societies for Coatings Technology in a paper presented by Walter Fibiger. The method is said to yield a reliable oil absorption figure for pigments with high specific surface areas, notably organic pigments.

Surfex '88 is the first UK exhibition with the new Akzo Corporate Identity to operate in a more market orientated structure. Within the chemical division of Akzo a group has been formed to promote the wide range of Akzo chemicals for coatings applications. Among the products that can be discussed will be:

To evaluate the photo, thermo, piezo and solvatochromism of new bis‐imidazole derived from three isomers of chlorobenzaldehyde.

The synthesis of the three new bis‐imidazoles was accomplished using modified procedure of the previously reported method, by dissolving the imidazol derivative and cooling in ice bath, and adding potassium ferricyanide drop wise. The compounds were used evaluate the effects of the position of the substitutions on the aromatic ring, on the photo, thermo and piezochromic properties.

New bis‐imidazole derived from 2‐chloro, 3‐chloro and 4‐chloro phenyl have been synthesised and their photochromic properties upon irradiation with ultraviolet light were studies in different solvents. The photochromic properties and performance were affected remarkably upon changing the solvent. Also, the thermochromic properties upon heating in different solvents were studied. The dimers showed piezochromism on grinding.

The method reported for the synthesis is simple. The new compounds showed photochromic, thermochromic, piezochromic, and solvatochromic making them potential candidates for many applications such as sensors, optical data storage and heat sensitive materials.

The method for preparation was modified and improved. The materials prepared were new compounds.