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Master thesis project: Optimization of dyeing temperature on tissue paper

Intresseområde (Area of interest): Ingenjör Miljö

Uppdragstyp (Type of assignment): Examensarbete/Uppsats

Beskrivning (description)

Tissue especially napkins and tablecloths come in a lot of different colours and varieties. The dyeing operation is made in the stock preparation before the tissue is formed by the paper machine. The dyeing of tissue is controlled by charges i.e opposite charged particles attracts and identically charged repulses. The cellulose fibres and the dye molecules are both negatively charged which requires fixation. The fixation is made by positively charged chemicals which fastens the negative particles together. One of the many challenges to dye tissue is to eliminate bleeding, e.g the colour releases when you dry your mouth (the tissue gets wet). This could happen if the dye is not fastened by the fixation chemicals.
In the papermaking process freshwater sometimes is needed especially during colour changes. This requires heating of the water and this is made by steam. The demand and use of steam should be as low as possible due to environmental/cost reasons. Therefore, is it important to understand how the temperature of the water influences the dye- and chemical consumption and other water parameters such as pH and charge.

Project goal
The goal of the thesis is to optimize the dyeing process by finding the temperature that gives the lowest dye consumption and still fulfil specification regarding colour values and colour fastness.

Proposed thesis project
The thesis project will use dyes, chemicals (salt, alum and fixing agents) and pulp as materials. Lab dyed samples will be done at different temperatures. The samples will be tested regarding colour values and colour fastness. Process water and back water will be analysed regarding remaining colour, pH and charge. The work can be done at Rexcell Tissue & Airlaid AB.

For the applicant
The project is suitable for chemical engineering students writing their master thesis. Travel expenses and reimbursement are paid according to agreement.

Sista ansökningsdag (application deadline): 2019-01-11

Arbetsgivare (employer)

Rexcell Tissue & Airlaid AB




Kontaktperson (contact person)

Marcus Martinsson