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Article

Gülçin Baysal, Gizem Keleş, Berdan Kalav, F. Seniha Güner and Burçak Karagüzel Kayaoğlu

In this study, it is aimed to synthesize ultraviolet (UV)-curable water-borne polyurethane acrylate (WPUA) binders using different types of polyols (poly (propylene…

Abstract

Purpose

In this study, it is aimed to synthesize ultraviolet (UV)-curable water-borne polyurethane acrylate (WPUA) binders using different types of polyols (poly (propylene glycol), PPG1000 and PPG2000 and poly (ethylene glycol), PEG1000 and PEG2000) at different molecular weights, DMPA (2,2-bis(hydroxymethyl) propionic acid) at different amounts and isophorone diisocyanate (IPDI) and use for pigment printing on synthetic leather.

Design/methodology/approach

UV-cured films were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC). The effect of binder structure on printing performance was determined with hardness, crock fastness, abrasion resistance and color measurements.

Findings

The highest abrasion resistance (60,000 cycles) and crock fastness values (dry crock and wet crock: 3/4) were obtained with binder PEG-C synthesized with PEG2000 and lower DMPA amount of 4.89 wt%; however, PEG-C binder showed lower hardness values. Due to lower urethane groups in PEG-C binder, more flexible films were obtained which imparted good adhesion property to printing film. Synthesized binders provided lower crock fastness and abrasion resistance properties than commercial WPUA binder.

Originality/value

Pigmented formulations including UV-curable water-borne synthesized PUA binder were developed and for the first time applied onto synthetic leather using screen printing method. Within this context, a new environmentally friendly printing method was proposed in this study including binder synthesis in the preparation of printing formulations.

Details

International Journal of Clothing Science and Technology, vol. 33 no. 2
Type: Research Article
ISSN: 0955-6222

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Article

Kim Clay, Ian Gardner, Eric Bresler, Mike Seal and Stuart Speakman

The industry standard for applying the identification nomenclature to Printed Circuit Boards (PCBs) is silkscreen legend printing, using white ink. This multi‐step process…

Abstract

The industry standard for applying the identification nomenclature to Printed Circuit Boards (PCBs) is silkscreen legend printing, using white ink. This multi‐step process has minimal flexibility for applying unique legends e.g. serialization numbers to individual boards. This paper describes a new, alternative single step direct legend printing system which uses piezoelectric inkjet technology, the leading digital imaging method for a variety of industrial applications. The advantages that this, inherently clean and efficient, drop‐on‐demand, printing process brings to legend printing include increased flexibility, shorter process times, good legend definition, accurate placement, small footprint equipment and reduced labour and material usage.

Details

Circuit World, vol. 28 no. 2
Type: Research Article
ISSN: 0305-6120

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Article

Tao Zhang, Kairui Zhang, Tao Li, Chaoxia Wang and Fan Yang

– The purpose of this paper is to prepare waterborne UV-curable pigment pastes for cotton fabric printing.

Abstract

Purpose

The purpose of this paper is to prepare waterborne UV-curable pigment pastes for cotton fabric printing.

Design/methodology/approach

O/W (oligomer-in-water) emulsions of polyurethane acrylate (PUA) oligomer in sodium dodecyl benzene sulphonate (SDBS) aqueous solution were prepared by ultrasonic emulsification method.

Findings

The present work studies various factors affecting the stability and droplet size of the O/W emulsion stabilised by SDBS. The optimal emulsifier concentration was 2.5 per cent, under which condition the stability of the emulsion increased as the emulsifier content increased, with a subsequent decrease in the droplet size of the emulsion, while above which emulsion agglomeration occurred. Increasing the power and duration of ultrasonic dispersion resulted in increased emulsion stability and decreased droplet size, while increases in the oligomer content reduced the emulsion stability. Darocure 1173 mixed with PUA and then emulsified in the SDBS aqueous solution guaranteed uniform dispersion of the photoinitiator, resulting in faster curing speed.

Originality/value

This paper presents a new method for making waterborne externally emulsified oligomers for UV curing, and finds that it is easy to convert the existing oligomers into waterborne equivalents by this method. Cotton fabrics printed with the oligomer emulsion based pastes were found to have good colour strength and crockfastness.

Details

Pigment & Resin Technology, vol. 43 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

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Article

J.W. Davison

In this paper the types of screen printing inks available for curing by ultra‐violet light are described. A comparison is made with conventional thermally cured inks and…

Abstract

In this paper the types of screen printing inks available for curing by ultra‐violet light are described. A comparison is made with conventional thermally cured inks and the author asserts that the current drive towards energy conservation and reduction in atmospheric pollution has been a powerful stimulus to the development of UV cured inks. The cost effectiveness of these inks is examined by reference to the energy required, operational costs, equipment, the ink itself and reject rates.

Details

Circuit World, vol. 3 no. 1
Type: Research Article
ISSN: 0305-6120

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Article

Tony Smith

A FORM of ultra‐violet curing was carried out by the Egyptians more than 3000 years ago when mummies were prepared by coating them with a resinous material and then left…

Abstract

A FORM of ultra‐violet curing was carried out by the Egyptians more than 3000 years ago when mummies were prepared by coating them with a resinous material and then left in the sun to cure. However, great advances in this method of accelerated drying have only taken place in the last 14 years.

Details

Pigment & Resin Technology, vol. 13 no. 10
Type: Research Article
ISSN: 0369-9420

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Abstract

Details

Pigment & Resin Technology, vol. 33 no. 4
Type: Research Article
ISSN: 0369-9420

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Article

C.A. Smith

The introduction of inks that cured, rather than dried, brought a completely new solution to the problem of drying. Ink is physically a liquid and will only dry when…

Abstract

The introduction of inks that cured, rather than dried, brought a completely new solution to the problem of drying. Ink is physically a liquid and will only dry when excited by some form of radiation. This is available in two forms.

Details

Pigment & Resin Technology, vol. 10 no. 9
Type: Research Article
ISSN: 0369-9420

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Article

Lifang Wu, Lidong Zhao, Meng Jian, Yuxin Mao, Miao Yu and Xiaohua Guo

In some three-dimensional (3D) printing application scenarios, e.g., model manufacture, it is necessary to print large-sized objects. However, it is impossible to…

Abstract

Purpose

In some three-dimensional (3D) printing application scenarios, e.g., model manufacture, it is necessary to print large-sized objects. However, it is impossible to implement large-size 3D printing using a single projector in digital light processing (DLP)-based mask projection 3D printing because of the limitations of the digital micromirror device chips.

Design/methodology/approach

A multi-projector DLP with energy homogenization (EHMP-DLP) scheme is proposed for large-size 3D printing. First, a large-area printing plane is established by tiling multiple projectors. Second, the projector set’s tiling pattern is obtained automatically, and the maximum printable plane is determined. Third, the energy is homogenized across the entire printable plane by adjusting gray levels of the images input into the projectors. Finally, slices are automatically segmented based on the tiling pattern of the projector set, and the gray levels of these slices are reassigned based on the images of the corresponding projectors.

Findings

Large-area high-intensity projection for mask projection 3D printing can be performed by tiling multiple DLP projectors. The tiled projector output energies can be homogenized by adjusting the images of the projectors. Uniform ultraviolet energy is important for high-quality printing.

Practical implications

A prototype device is constructed using two projectors. The printable area becomes 140 × 210 mm from the original 140 × 110 mm.

Originality/value

The proposed EHMP-DLP scheme enables 3D printing of large-size objects with linearly increasing printing times and high printing precision. A device was established using two projectors to practice the scheme and can easily be extended to larger sizes by using more projectors.

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Article

Qinguo Fan, Hongxia Xue and Yong K. Kim

Woven and knitted polyester fabrics were pretreated with formulations containing waterborne UV curable resins and silica particles to improve inkjet print quality. The…

Abstract

Woven and knitted polyester fabrics were pretreated with formulations containing waterborne UV curable resins and silica particles to improve inkjet print quality. The selected formulations were applied with low add-on to reduce the adverse effect on fabric hand without sacrificing the print quality. A print pattern with block areas and lines in cyan, magenta, yellow, and black colors was designed and inkjet printed on the pretreated fabrics with a wide-format inkjet printer (Encad Novajet 750) to investigate the effects of the UV curable pretreatment on the inkjet print color qualities including color depth, color gamut and color lightness.

Experimental results show that both the color depth and gamut of prints on the pretreated taffeta and knitted polyester fabrics were enhanced compared to those on untreated polyester fabrics. However, both the color depth and gamut of the prints on the pretreated satin polyester fabrics were reduced. The lightness change of the inkjet printed colors on pretreated knitted fabrics is similar to that of untreated fabrics whereas the lightness change of prints on pretreated satin and taffeta fabrics shows some differences. All colors have increased lightness on pretreated satin fabrics. However, magenta and black have decreased lightness on the pretreated taffeta fabrics.

Details

Research Journal of Textile and Apparel, vol. 12 no. 1
Type: Research Article
ISSN: 1560-6074

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Article

Evgeny Morozov, Mikhail Novikov, Vyacheslav Bouznik and Gleb Yurkov

Active employment of additive manufacturing for scaffolds preparation requires the development of advanced methods which can accurately characterize the morphologic…

Abstract

Purpose

Active employment of additive manufacturing for scaffolds preparation requires the development of advanced methods which can accurately characterize the morphologic structure and its changes during an interaction of the scaffolds with substrate and aqueous medium. This paper aims to use the method of nuclear magnetic resonance (NMR) imaging for preclinical characterization of 3D-printed scaffolds based on novel allyl chitosan biocompatible polymer matrices.

Design/methodology/approach

Biocompatible polymer scaffolds were fabricated via stereolithography method. Using NMR imaging the output quality control of the scaffolds was performed. Scaffolds stability, polymer matrix homogeneity, kinetic of swelling processes, water migration pathways within the 3D-printed parts, effect of post-print UV curing on overall scaffolds performance were studied in details.

Findings

NMR imaging visualization of water uptake and polymer swelling processes during the interaction of scaffolds with aqueous medium revealed the formation of the fronts within the polymer matrices those dynamics is governed by case I transport (Fickian diffusion) of the water into polymer network. No significant difference was observed in front propagation rates along the polymer layers and across the layers stack. After completing the swelling process, the polymer scaffolds retain their integrity and no internal defects were detected.

Research limitations/implications

NMR imaging revealed that post-print UV curing aimed to improve the overall performance of 3D-printed scaffolds might not provide a better quality of the finish product, as this procedure apparently yield strongly inhomogeneous distribution of polymer crosslink density which results in subsequent inhomogeneity of water ingress and swelling processes, accompanied by stress-related cracks formation inside the scaffolds.

Practical implications

This study introduces a method which can successfully complement the standard tests which now are widely used in either additive manufacturing or scaffolds engineering.

Social implications

This work can help to improve the overall performance of the polymer scaffolds used in tissue engineering.

Originality/value

The results of this study demonstrate feasibility of NMR imaging for preclinical characterization of 3D printed biocompatible polymer scaffolds. The results are believed to contribute to better understanding of the processes vital for improving the design of 3D-printed polymer scaffolds.

Details

Rapid Prototyping Journal, vol. 25 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

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