{"id":10994,"date":"2026-03-12T09:29:23","date_gmt":"2026-03-12T09:29:23","guid":{"rendered":"https:\/\/fsxchemical.com\/?p=10994"},"modified":"2026-08-29T09:31:51","modified_gmt":"2026-08-29T09:31:51","slug":"alkali-addition-timing-sodium-alginate-reactive-printing-paste-stability","status":"publish","type":"post","link":"https:\/\/fsxchemical.com\/vi\/blog\/alkali-addition-timing-sodium-alginate-reactive-printing-paste-stability\/","title":{"rendered":"How Alkali Addition Timing Affects Sodium Alginate Reactive Printing Paste Stability"},"content":{"rendered":"<p class=\"wp-block-wd-paragraph wd-39631ba5\"><em>Alkali is essential for reactive dye fixation, but when it is added to a sodium alginate printing paste can materially affect the usable working window. Adding alkali too early exposes the reactive dye to an alkaline aqueous environment before printing and steaming, increasing the risk of premature dye hydrolysis and shade loss. At the same time, alkali changes pH and ionic strength, which can also change the rheology of the complete printing paste depending on the alginate grade, water quality, temperature and auxiliary package. This guide explains why alkali-last addition is often used, how sodium bicarbonate differs from stronger alkali routes, and how textile mills should validate paste stability from preparation through steaming and wash-off.<\/em><\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-fefea575\">Why Alkali Addition Timing Matters<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-7fc7ea4d\">Reactive dyes require alkaline conditions to react efficiently with suitable cellulose fibers such as cotton and viscose.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-dcb40883\">That creates a practical tension:<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-d1042536\"><strong>The dye needs alkali for fixation\u2014but the color paste should not spend unnecessary time in alkaline water before printing.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-99a3901d\">If alkali is added too early, the paste may remain alkaline for hours before it reaches the fabric and steamer.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-e01925f2\">During that time, several changes can occur:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Reactive dye can hydrolyze in the aqueous phase.<\/li>\n\n\n\n<li>Shade and color yield can drift.<\/li>\n\n\n\n<li>Paste viscosity can change.<\/li>\n\n\n\n<li>The usable production window can shorten.<\/li>\n\n\n\n<li>Warm color-kitchen conditions can accelerate instability.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-1b1d9a05\">This is why many reactive-printing procedures prepare the sodium alginate base first, dissolve the dye and auxiliaries, cool the system where needed, and add alkali as close to printing as practical.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-03949954\">The exact timing should be validated by the mill rather than copied as a universal rule.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-1d4381d5\">Two Different Aging Mechanisms: Dye Hydrolysis vs. Paste Rheology<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-d8d1748b\">When an alkali-containing reactive paste ages, two different types of instability can occur.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-3f45c0dc\">1. Reactive Dye Chemical Aging<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-89b8d241\">The reactive dye is designed to react with nucleophilic hydroxyl groups on cellulose under alkaline conditions.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-8ea373ed\">But water also contains hydroxyl functionality.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-227808a3\">If the dye remains in an alkaline aqueous paste before reaching the fiber, part of the reactive group can hydrolyze.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-c0418941\">Hydrolyzed reactive dye has lost the reactive functionality needed for efficient covalent fixation to cellulose.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-ced72042\">This can reduce useful fixation and increase unfixed dye in washing.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-fa36ee28\">2. Printing-Paste Rheological Aging<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-1bb4a1b4\">Separately, the complete paste may change in:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u0110\u1ed9 nh\u1edbt<\/li>\n\n\n\n<li>Shear response<\/li>\n\n\n\n<li>Gel or particle formation<\/li>\n\n\n\n<li>Foam<\/li>\n\n\n\n<li>Screen running<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-4b0d0bfb\">These changes can come from pH, ionic strength, temperature, water hardness, auxiliaries or the alginate grade.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-13fd0be3\"><strong>Do not assume that every old-paste color loss is caused by sodium alginate degradation.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-e3ec32ba\">Likewise, a stable viscosity reading does not prove the reactive dye is still chemically fresh.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-b37f76cf\">What Does Alkali Actually Do in Reactive Printing?<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-9e13e3a6\">Alkali raises the pH so cellulose hydroxyl groups become more reactive toward the reactive dye during fixation.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-b76e1b0e\">In a simplified process:<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-d3095224\"><strong>Reactive Dye + Cellulose + Alkali + Heat\/Moisture \u2192 Dye-Fiber Covalent Fixation<\/strong><\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-b6ff6e01\">Common alkali systems can include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Natri bicacbonat<\/li>\n\n\n\n<li>Sodium carbonate<\/li>\n\n\n\n<li>Blended alkali systems<\/li>\n\n\n\n<li>Other route-specific alkaline packages<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-70bd7df6\">The correct alkali depends on:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Reactive dye class<\/li>\n\n\n\n<li>Dye reactivity<\/li>\n\n\n\n<li>V\u1ea3i<\/li>\n\n\n\n<li>Steaming or fixation conditions<\/li>\n\n\n\n<li>Required paste stability<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-b5ca3162\">A higher pH is not automatically better.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-e2dcc6dc\">The target is enough alkalinity during fixation without creating unnecessary pre-print hydrolysis or paste instability.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-d21be856\">Single-Phase Printing: Why Alkali Is Commonly Added Late<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-664ad672\">In single-phase reactive printing, dye, thickener and alkali are present in the same printing paste.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-f80bc43f\">A practical preparation sequence often follows:<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-dbb8a31a\"><strong>Sodium Alginate Base \u2192 Dye\/Auxiliary Solution \u2192 Mix \u2192 Cool if Needed \u2192 Add Alkali \u2192 Final Adjustment \u2192 Print<\/strong><\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-98eee7ec\">The purpose of late alkali addition is not to suggest that sodium alginate instantly fails in alkaline conditions.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-9515c35d\">It is mainly to minimize the time during which reactive dye is exposed to alkaline water before fixation.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-0c4ff175\">Late addition can also help the mill:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Keep a neutral or lower-pH master paste available longer.<\/li>\n\n\n\n<li>Activate only the quantity needed for the upcoming print run.<\/li>\n\n\n\n<li>Reduce waste from unused alkaline color paste.<\/li>\n\n\n\n<li>Compare pot life more predictably.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-3c017e76\">This is particularly useful in color kitchens preparing multiple shades.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-1c18e96e\">Two-Phase Printing: Separating Alkali from the Color Paste<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-c57f4362\">In two-phase reactive printing, the alkali is not necessarily stored inside the dye-containing printing paste.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-acca8284\">Instead, the alkaline component can be introduced in a separate process stage, depending on the mill&#8217;s equipment and dye system.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-80fa184a\">This can reduce the time that reactive dye remains in alkaline water before fixation.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-668abcd5\">Potential advantages include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Longer color-paste storage window<\/li>\n\n\n\n<li>Lower risk of premature dye hydrolysis<\/li>\n\n\n\n<li>More stable shade during long runs<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-23dd776c\">However, the process becomes more dependent on:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Uniform alkali application<\/li>\n\n\n\n<li>Fabric pickup<\/li>\n\n\n\n<li>S\u1ea5y kh\u00f4<\/li>\n\n\n\n<li>Registration of the complete process<\/li>\n\n\n\n<li>Steaming\/fixation control<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-bd53066a\">Two-phase printing is therefore not automatically better; it is a different process architecture with different control points.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-7e98e9de\">Sodium Bicarbonate vs. Sodium Carbonate and Stronger Alkali Routes<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-56e5b5c1\">Sodium bicarbonate is widely used in reactive printing because it is a relatively mild alkali at room temperature and can provide a useful balance between paste stability and fixation.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-3c101394\">During heating and steaming, the effective alkalinity can increase, supporting reactive dye fixation.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-f79376c9\">Stronger alkali systems can provide faster or stronger alkaline conditions but may also reduce the pre-print stability window for some dye systems.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-221c4a8c\">That means alkali timing becomes more important as:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Alkalinity increases<\/li>\n\n\n\n<li>Paste temperature increases<\/li>\n\n\n\n<li>Dye reactivity increases<\/li>\n\n\n\n<li>Holding time increases<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-43bdcc9b\">Do not replace sodium bicarbonate with sodium carbonate or another stronger alkali on a universal one-to-one basis.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-8f93e31f\">Validate the actual reactive dye class and fixation route.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-f15d153c\">How Early Alkali Addition Can Increase Reactive Dye Hydrolysis<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-1276a123\">Reactive dye hydrolysis is one of the main reasons alkali timing matters.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-9802c2f1\">When the reactive dye remains in alkaline water, part of the dye can react with water instead of cellulose.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-c96ed9f2\">This can produce:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Lower effective fixation<\/li>\n\n\n\n<li>Lower final K\/S<\/li>\n\n\n\n<li>Shade drift<\/li>\n\n\n\n<li>More unfixed color in washing<\/li>\n\n\n\n<li>Higher wash-water color load<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-c0e18659\">The rate depends on:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Dye reactive group chemistry<\/li>\n\n\n\n<li>pH<\/li>\n\n\n\n<li>Nhi\u1ec7t \u0111\u1ed9<\/li>\n\n\n\n<li>Time<\/li>\n\n\n\n<li>Dye concentration<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-df17cdc9\">A more reactive dye may require a shorter alkaline holding window than a more storage-stable dye system.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-8cd67084\">This is why \u201cpaste can stand for X hours\u201d should not be treated as a universal sodium alginate property.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-79be24c2\">Pot life belongs to the complete <strong>dye + alkali + thickener + temperature<\/strong> system.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-124bd960\">How Alkali Can Change Sodium Alginate Paste Rheology<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-b60e07cd\">Sodium alginate is generally compatible with the moderate alkaline conditions used in many reactive printing systems, but the complete paste can still show rheological changes after alkali addition.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-ba9d0459\">Possible causes include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Higher ionic strength<\/li>\n\n\n\n<li>Different sodium-ion concentration<\/li>\n\n\n\n<li>Water hardness<\/li>\n\n\n\n<li>Interaction with dyes or auxiliaries<\/li>\n\n\n\n<li>Nhi\u1ec7t \u0111\u1ed9<\/li>\n\n\n\n<li>Long holding time<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-0dbf71ee\">Possible observations include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Viscosity decrease<\/li>\n\n\n\n<li>Viscosity increase<\/li>\n\n\n\n<li>Different shear thinning<\/li>\n\n\n\n<li>Gel particles<\/li>\n\n\n\n<li>Different screen release<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-5bb2df5d\"><strong>Do not diagnose \u201calkaline hydrolysis of alginate\u201d from one viscosity change alone.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-aff92e5b\">First compare the same alginate paste with and without alkali under the same temperature, holding time and water conditions.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-2b07c9f5\">Why Temperature Makes Timing More Important<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-1b385e0c\">Temperature accelerates chemical reactions.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-3bba17f0\">A color paste prepared at 20\u201325\u00b0C may age differently from the same paste held in a hot production area.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-7cf06c85\">Higher temperature can accelerate:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Reactive dye hydrolysis<\/li>\n\n\n\n<li>Paste viscosity drift<\/li>\n\n\n\n<li>Evaporation<\/li>\n\n\n\n<li>Microbial or storage changes in longer holding situations<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-a2d36bce\">This creates an important production rule:<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-5ddc4f4a\"><strong>Alkali timing should be validated at the real color-kitchen temperature\u2014not only under laboratory air conditioning.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-37c09a9d\">If seasonal conditions are very different, repeat the pot-life study in the hotter season.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-94b9344a\">Paste Holding Time: Build a Real Working Window<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-3a9c6d75\">Do not approve an alkali-containing printing paste with only an immediate test.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-32f822f1\">Record the paste at several realistic time points, for example:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Immediately after alkali addition<\/li>\n\n\n\n<li>Before printing starts<\/li>\n\n\n\n<li>During the expected production run<\/li>\n\n\n\n<li>Near the end of the planned working period<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-f09da9a2\">At each point, check:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u0110\u1ed9 nh\u1edbt<\/li>\n\n\n\n<li>pH<\/li>\n\n\n\n<li>H\u00ecnh th\u1ee9c<\/li>\n\n\n\n<li>Screen running<\/li>\n\n\n\n<li>Printed color<\/li>\n\n\n\n<li>Final K\/S after steaming\/washing<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-0e1457fc\">The correct maximum holding time is the point at which all important properties remain inside the mill&#8217;s approved window.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-23b7b5fc\">Do not use a universal \u201csame-day\u201d or \u201c24-hour\u201d rule without validation.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-a8404bbc\">Recommended Trial Logic for Addition Order<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-4f6eb7a4\">A useful development comparison can include several preparation routes.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-65004dfb\">Route A: Alkali Added Early<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-72db0805\">Prepare the full color paste including alkali and hold for the realistic pre-print period.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-da81c867\">Route B: Alkali Added Late<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-b86cec01\">Prepare the alginate\/dye master paste, hold it under the same conditions, then add alkali shortly before printing.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-bf245256\">Route C: Two-Phase Reference Where Available<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-e737bb1c\">Keep the dye paste and main alkali function in separate process stages.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-74a066b8\">Then compare all routes using the same:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>V\u1ea3i<\/li>\n\n\n\n<li>Dye loading<\/li>\n\n\n\n<li>Printing machine<\/li>\n\n\n\n<li>S\u1ea5y kh\u00f4<\/li>\n\n\n\n<li>H\u1ea5p<\/li>\n\n\n\n<li>Gi\u1eb7t gi\u0169<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-90fc4dd5\">This makes the effect of timing visible instead of relying on assumptions.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-128afaf7\">Water Hardness, Calcium and Alkali Timing<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-1330a2aa\">Plant water is another variable.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-9802347a\">Calcium can strongly interact with sodium alginate and create:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Local viscosity increase<\/li>\n\n\n\n<li>Gel particles<\/li>\n\n\n\n<li>Filtration residue<\/li>\n\n\n\n<li>Calcium-alginate-type insoluble structures<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-49f3e11c\">Alkali addition can also change the ionic environment of the paste.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-5314eef0\">If paste stability changes after alkali addition, compare:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Plant water<\/li>\n\n\n\n<li>Soft\/DI reference water<\/li>\n\n\n\n<li>Total hardness<\/li>\n\n\n\n<li>Calcium level<\/li>\n\n\n\n<li>Conductivity<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-724674c3\">Otherwise, a water-quality problem can be mistaken for an alkali-timing problem.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-a290b7af\">Review the related guide on <a href=\"https:\/\/fsxchemical.com\/vi\/water-hardness-calcium-sodium-alginate-printing-paste\/\">water hardness and calcium ions in sodium alginate printing paste<\/a> when calcium-related gelation is suspected.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-fcf5b267\">Screen Running and Print Definition After Alkali Addition<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-7f8fd8e8\">A paste can maintain acceptable average viscosity but still change its machine behavior after alkali addition.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-1f893731\">Evaluate:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Screen passage<\/li>\n\n\n\n<li>Squeegee transfer<\/li>\n\n\n\n<li>Fine-line sharpness<\/li>\n\n\n\n<li>Solid-area uniformity<\/li>\n\n\n\n<li>Foam<\/li>\n\n\n\n<li>Screen drying<\/li>\n\n\n\n<li>Long-run consistency<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-e9497a55\">If late alkali addition produces a better fresh paste but the viscosity has not fully equilibrated before printing, the machine may see another kind of variation.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-bdcdb61d\">Therefore, \u201cadd immediately before printing\u201d does not necessarily mean \u201cadd seconds before the screen.\u201d<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-092e3fad\">Define a short but controlled mixing\/equilibration period that gives uniform alkali distribution before the paste enters production.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-8a3d7020\">Color Yield, Shade and Background Cleanliness<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-5bde5d39\">When comparing alkali timing, evaluate the finished print\u2014not only the wet paste.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-b0e00697\">Look for:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>K\/S or color strength<\/li>\n\n\n\n<li>Shade change<\/li>\n\n\n\n<li>Brightness<\/li>\n\n\n\n<li>Background staining<\/li>\n\n\n\n<li>\u0110\u1ed9 s\u1eafc n\u00e9t c\u1ee7a c\u1ea1nh<\/li>\n\n\n\n<li>Penetration<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-a09e8c81\">An old alkaline paste can still print cleanly but give lower final color because part of the reactive dye has already hydrolyzed.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-567c6499\">Conversely, a very fresh high-alkali paste can produce acceptable color but poor screen stability if the chemical package is not fully compatible.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-b4dea1f9\">This is why color and rheology must be approved together.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-cbb72809\">Steaming: Where Alkali Must Finally Do Its Job<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-0379911f\">The purpose of delaying alkali is not to reduce fixation.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-663c6ca3\">The goal is to preserve dye reactivity before printing while still creating the correct alkaline condition during fixation.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-00716f55\">During steaming, moisture and heat allow:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Dye dissolution\/mobility<\/li>\n\n\n\n<li>Fiber swelling<\/li>\n\n\n\n<li>Alkali activation<\/li>\n\n\n\n<li>Dye-fiber reaction<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-3b28cf37\">The correct steaming temperature and time depend on the reactive dye class, fabric and process.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-0d4ba700\">Do not publish or adopt one universal steaming schedule from a generic article.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-498d130c\">Use the dye supplier&#8217;s process as the starting condition and validate the complete paste.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-e32767a7\">Wash-Off and Hydrolyzed Dye<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-676e0c36\">After fixation, unfixed and hydrolyzed reactive dye must be removed during rinsing and soaping.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-07c492cc\">If early alkali addition increases dye hydrolysis, the mill can see:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>More color in wash water<\/li>\n\n\n\n<li>More intensive washing demand<\/li>\n\n\n\n<li>Higher risk of back-staining<\/li>\n\n\n\n<li>Lower useful fixation efficiency<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-14c3374d\">Sodium alginate itself should also wash away cleanly under the validated water conditions.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-b3b7e999\">Final approval should therefore include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u0110\u1ed9 s\u1ea1ch sau khi r\u1eeda tr\u00f4i<\/li>\n\n\n\n<li>White-ground cleanliness where relevant<\/li>\n\n\n\n<li>Rubbing\/washing fastness<\/li>\n\n\n\n<li>Fabric hand<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-d7cbbfcd\">How to Build an Alkali-Timing Stability Test<\/h2>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-284f2e37\">Step 1: Prepare One Sodium Alginate Master Paste<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-389c19b0\">Use the same alginate batch, concentration, water and hydration method.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-184e86b6\">Step 2: Prepare One Dye\/Auxiliary Master<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-03c4dc47\">Use the same dye lot and supporting chemicals.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-01c10f5b\">Step 3: Split into Equal Samples<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-e8b1ff1c\">This reduces batch-to-batch preparation variation.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-df123090\">Step 4: Add Alkali at Different Times<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-40d96327\">For example:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Sample A: Alkali added at time zero<\/li>\n\n\n\n<li>Sample B: Alkali added after part of the holding period<\/li>\n\n\n\n<li>Sample C: Alkali added shortly before the controlled printing trial<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-c46938d1\">The exact intervals should match the factory&#8217;s real workflow.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-861d86e9\">Step 5: Standardize Mixing After Alkali Addition<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-f4608e4e\">Use the same mixing time and intensity.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-64c219a3\">Step 6: Measure Before Printing<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-b506408a\">Record:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u0110\u1ed9 nh\u1edbt<\/li>\n\n\n\n<li>pH<\/li>\n\n\n\n<li>Nhi\u1ec7t \u0111\u1ed9<\/li>\n\n\n\n<li>H\u00ecnh th\u1ee9c<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-55415609\">Step 7: Print and Process Identically<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-1c064077\">Use the same fabric, screen, drying, steaming and washing conditions.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-0d550ea1\">Step 8: Evaluate Finished Results<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-aa228584\">Compare:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>K\/S<\/li>\n\n\n\n<li>Shade<\/li>\n\n\n\n<li>Print definition<\/li>\n\n\n\n<li>R\u1eeda tr\u00f4i<\/li>\n\n\n\n<li>Fastness<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-6b8db7b5\">This test directly shows whether late alkali addition creates a measurable production benefit.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-0bd84c4a\">Production Approval Workflow<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-1cb461eb\">After laboratory screening, approve the preferred timing route at production scale.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-9671217f\">Verify:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Large-batch mixing uniformity<\/li>\n\n\n\n<li>Alkali dosing accuracy<\/li>\n\n\n\n<li>Short equilibration after alkali addition<\/li>\n\n\n\n<li>Color-kitchen holding time<\/li>\n\n\n\n<li>Machine running stability<\/li>\n\n\n\n<li>Beginning-to-end shade consistency<\/li>\n\n\n\n<li>Steaming repeatability<\/li>\n\n\n\n<li>R\u1eeda tr\u00f4i<\/li>\n\n\n\n<li>Repeat-batch consistency<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-d94a7c2c\">Keep a record of:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Alginate batch<\/li>\n\n\n\n<li>Dye lot<\/li>\n\n\n\n<li>Alkali type and dosage<\/li>\n\n\n\n<li>Time of alkali addition<\/li>\n\n\n\n<li>Paste temperature<\/li>\n\n\n\n<li>Time printing started<\/li>\n\n\n\n<li>Time printing ended<\/li>\n\n\n\n<li>Finished color reference<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-33f56fcd\">This turns alkali timing from an operator habit into a controlled process variable.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-ce1e0052\">Troubleshooting Table<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Observed Problem<\/th><th>First Variables to Check<\/th><th>Do Not Assume<\/th><\/tr><\/thead><tbody><tr><td>Old alkaline paste gives lower K\/S<\/td><td>Dye hydrolysis, holding time, temperature, pH<\/td><td>Alginate viscosity is the only cause<\/td><\/tr><tr><td>Viscosity changes immediately after alkali<\/td><td>Ionic strength, water hardness, alginate grade, mixing<\/td><td>Alginate has necessarily degraded<\/td><\/tr><tr><td>Fresh paste prints well but changes during shift<\/td><td>Pot life, paste temperature, evaporation, dye hydrolysis<\/td><td>Machine settings are the only cause<\/td><\/tr><tr><td>Late-added alkali gives uneven first meters<\/td><td>Mixing\/equilibration time, dosing uniformity<\/td><td>Late addition is inherently unstable<\/td><\/tr><tr><td>Shade drifts but viscosity stays constant<\/td><td>Reactive dye hydrolysis and temperature<\/td><td>Stable viscosity proves fresh dye chemistry<\/td><\/tr><tr><td>Gel particles appear after alkali addition<\/td><td>Calcium, hard water, local concentration, mixing order<\/td><td>Alkali alone is responsible<\/td><\/tr><tr><td>Wash water becomes more heavily colored<\/td><td>Hydrolyzed\/unfixed dye, alkali timing, fixation<\/td><td>More washing chemical is the first solution<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-c3446c69\">Total Cost in Use<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-384648fc\">Alkali timing is also a commercial variable.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-283f0c0b\">Early alkali addition can increase:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Unused color-paste waste<\/li>\n\n\n\n<li>Shade correction<\/li>\n\n\n\n<li>Reprinting<\/li>\n\n\n\n<li>Wash-off load<\/li>\n\n\n\n<li>Wastewater color<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-77ae1a8d\">Late controlled addition can reduce some of those losses, but it may require:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>More disciplined color-kitchen procedures<\/li>\n\n\n\n<li>Accurate alkali dosing<\/li>\n\n\n\n<li>Additional mixing control<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-cd40b902\">A useful framework is:<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-46b96bca\"><strong>Total Cost in Use = Alginate + Dye + Alkali\/Auxiliaries + Color-Paste Waste + Machine Loss + Steaming\/Washing + Rework<\/strong><\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-9ddf9b5d\">The best alkali-timing policy is the one that gives stable shade and rheology at the lowest repeatable production cost.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-d61bc4b6\">What Information Should You Send to a Sodium Alginate Supplier?<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-3628628f\">If your reactive paste changes after alkali addition, send:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Current sodium alginate TDS or sample<\/li>\n\n\n\n<li>Alginate concentration<\/li>\n\n\n\n<li>Viscosity and complete test method<\/li>\n\n\n\n<li>Reactive dye brand\/class<\/li>\n\n\n\n<li>Dye loading<\/li>\n\n\n\n<li>Alkali type and dosage<\/li>\n\n\n\n<li>Exact timing of alkali addition<\/li>\n\n\n\n<li>Paste pH<\/li>\n\n\n\n<li>Paste temperature<\/li>\n\n\n\n<li>Holding time before and during printing<\/li>\n\n\n\n<li>Water hardness\/calcium where relevant<\/li>\n\n\n\n<li>Complete or simplified formula<\/li>\n\n\n\n<li>Flat or rotary screen<\/li>\n\n\n\n<li>Steaming conditions<\/li>\n\n\n\n<li>Washing\/soaping process<\/li>\n\n\n\n<li>Current viscosity, shade, fixation or wash-off problem<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-08d39b9b\">FSX Chemical can use this information through <a href=\"https:\/\/fsxchemical.com\/vi\/dich-vu\/cac-mau-trung-khop\/\">M\u1eabu v\u00e0 vi\u1ec7c k\u1ebft h\u1ee3p<\/a> to compare a relevant sodium alginate route under the customer&#8217;s actual alkali-timing and process conditions.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-3c7ad4ea\">How Should a Mill Control Alkali Addition Timing?<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-1befeaae\">A practical decision chain is:<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-907fe2b7\"><strong>Prepare Stable Alginate\/Dye Master \u2192 Define Alkali Type \u2192 Add at Controlled Time \u2192 Mix\/Equilibrate \u2192 Print Within Validated Window \u2192 Steam \u2192 Wash \u2192 Check Shade and Fastness<\/strong><\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-1b0d105e\">The key principles are:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Alkali is required for fixation, but unnecessary alkaline holding time increases pre-print risk.<\/strong><\/li>\n\n\n\n<li><strong>Reactive dye hydrolysis and sodium alginate rheology are separate stability questions.<\/strong><\/li>\n\n\n\n<li><strong>Late alkali addition is often useful, but it still requires controlled mixing and a defined equilibration time.<\/strong><\/li>\n\n\n\n<li><strong>Sodium bicarbonate and stronger alkali systems should not be treated as interchangeable.<\/strong><\/li>\n\n\n\n<li><strong>Temperature and water quality can shorten the usable working window.<\/strong><\/li>\n\n\n\n<li><strong>Approve timing from the finished print after steaming and washing\u2014not from paste viscosity alone.<\/strong><\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-26b7420f\">Frequently Asked Questions<\/h2>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-f281ea9f\">1. Why is alkali added to reactive printing paste?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-5a1977b2\">Alkali creates the alkaline condition needed for reactive dye fixation with suitable cellulose fibers during steaming or another approved fixation process.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-8a5f2c8d\">2. Should alkali be added to sodium alginate paste at the beginning?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-67e48058\">Not automatically. In many single-phase systems, alkali is added relatively late to reduce the time reactive dye spends in alkaline water before printing.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-17e9a68a\">3. Why can early alkali addition reduce color yield?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-4a0ddedd\">Reactive dye can hydrolyze in alkaline water before reaching cellulose, reducing the amount of dye still capable of covalent fixation.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-aeac9560\">4. Does alkali destroy sodium alginate?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-d91c1972\">Not necessarily. Sodium alginate is compatible with many normal reactive-printing alkali conditions. A viscosity change after alkali addition should be investigated for ionic strength, water hardness, temperature and other formula effects before concluding polymer degradation.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-8dad2cae\">5. Is sodium bicarbonate better than sodium carbonate?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-69816be6\">Neither is universally better. Sodium bicarbonate is milder and often offers a useful paste-stability\/fixation balance, while stronger alkali routes may suit other dye classes and processes.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-3a2789f4\">6. How long can reactive printing paste be stored after alkali addition?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-375e9a82\">There is no universal holding time. It depends on dye reactivity, alkali type, pH, temperature, alginate grade and complete formulation. Build a mill-specific pot-life test.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-1dbcdf37\">7. Can viscosity stay stable while the dye is already hydrolyzing?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-3a739fd1\">Yes. Rheological stability and dye chemical stability are different. Always compare the finished print as well as paste viscosity.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-194082de\">8. Does late alkali addition mean printing immediately after dosing?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-4e7215d4\">Not necessarily. The paste still needs controlled mixing and enough time for uniform alkali distribution. Define a short, repeatable equilibration step.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-f837e095\">9. Does hot weather shorten reactive paste pot life?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-040a1906\">It can. Higher temperature generally accelerates reactive dye hydrolysis and can also increase paste viscosity drift or evaporation.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-5eddd4d3\">10. Can hard water make alkali-related paste instability worse?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-ac8d144c\">Yes. Calcium can interact strongly with sodium alginate, so a water-quality problem can appear when the ionic environment changes after alkali addition.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-e9b532db\">11. Is two-phase reactive printing more stable?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-de28e847\">Separating the main alkali function from the stored color paste can extend dye-paste stability, but two-phase routes require separate control of alkali application, pickup and fixation.<\/p>\n\n\n\n<h3 class=\"wp-block-wd-title title wd-f6b30468\">12. What should I send FSX Chemical for alkali-timing troubleshooting?<\/h3>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-8adaa889\">Send the alginate TDS\/sample, reactive dye, alkali type\/dosage, timing of addition, pH, temperature, holding time, water data, viscosity method and steaming\/washing conditions.<\/p>\n\n\n\n<h2 class=\"wp-block-wd-title title wd-a2e0a890\">Optimize Sodium Alginate Paste Stability Before Alkali Becomes a Problem<\/h2>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-aedcd5c5\">If your reactive printing paste loses color strength, drifts in viscosity or becomes less consistent during long runs after alkali addition, FSX Chemical can help separate dye hydrolysis from thickener and water-quality effects.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-1d67f2cb\">For a useful technical comparison, send:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Your current sodium alginate sample, TDS or COA<\/li>\n\n\n\n<li>Alginate concentration<\/li>\n\n\n\n<li>Viscosity and complete test method<\/li>\n\n\n\n<li>Reactive dye class and loading<\/li>\n\n\n\n<li>Alkali type and dosage<\/li>\n\n\n\n<li>When alkali is added<\/li>\n\n\n\n<li>Paste pH and temperature<\/li>\n\n\n\n<li>Holding time before\/during printing<\/li>\n\n\n\n<li>Plant-water hardness where relevant<\/li>\n\n\n\n<li>Complete or simplified paste formula<\/li>\n\n\n\n<li>Screen-printing route<\/li>\n\n\n\n<li>Steaming and washing conditions<\/li>\n\n\n\n<li>Current shade, viscosity, fixation or wash-off target<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-ac057d0f\">B\u1eaft \u0111\u1ea7u b\u1eb1ng <a href=\"https:\/\/fsxchemical.com\/vi\/dich-vu\/cac-mau-trung-khop\/\">M\u1eabu v\u00e0 vi\u1ec7c k\u1ebft h\u1ee3p<\/a> to build a controlled alkali-timing comparison.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-2516f207\">\u0110\u00e1nh gi\u00e1 <a href=\"https:\/\/fsxchemical.com\/vi\/product\/alginat-natri\/\">FSX Chemical Sodium Alginate<\/a> for current textile-printing grade options.<\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-ad47ff2e\">You can also <a href=\"https:\/\/fsxchemical.com\/vi\/dich-vu\/yeu-cau-bao-gia\/\">Request a Factory-Direct Quote<\/a> after the suitable grade and process window are confirmed or <a href=\"https:\/\/fsxchemical.com\/vi\/lien-he-voi-chung-toi\/\">Li\u00ean h\u1ec7 v\u1edbi FSX Chemical<\/a> for technical discussion\ud83d\udce7\u00a0<strong>Email<a href=\"https:\/\/fsxchemical.com\/vi\/lien-he-voi-chung-toi\/\">: Service@fsxchemical.com<\/a><\/strong><\/p>\n\n\n\n<p class=\"wp-block-wd-paragraph wd-3fdab335\"><strong>In reactive printing, alkali should be present strongly enough and long enough to drive fixation\u2014but not unnecessarily early enough to consume dye reactivity before the paste reaches the fabric.<\/strong><\/p>","protected":false},"excerpt":{"rendered":"<p>Alkali is required for reactive dye fixation, but adding it too early can expose reactive dye to alkaline water before printing and steaming. This can shorten the usable paste window through dye hydrolysis and, depending on the formula, rheological changes.<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_titles_title":"How Alkali Addition Timing Affects Sodium Alginate Reactive Printing Paste Stability","_seopress_titles_desc":"Learn how alkali addition timing affects sodium alginate reactive printing paste stability, dye hydrolysis, viscosity, shade consistency, steaming and wash-off.","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","footnotes":""},"categories":[1],"tags":[1498,1501,1388,1500,1115,87,1499],"class_list":["post-10994","post","type-post","status-publish","format-standard","hentry","category-technical-guides","tag-alkali-addition","tag-pot-life","tag-printing-paste-stability","tag-reactive-dye-hydrolysis","tag-reactive-printing","tag-sodium-alginate","tag-sodium-bicarbonate"],"acf":[],"_links":{"self":[{"href":"https:\/\/fsxchemical.com\/vi\/wp-json\/wp\/v2\/posts\/10994","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fsxchemical.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fsxchemical.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fsxchemical.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fsxchemical.com\/vi\/wp-json\/wp\/v2\/comments?post=10994"}],"version-history":[{"count":2,"href":"https:\/\/fsxchemical.com\/vi\/wp-json\/wp\/v2\/posts\/10994\/revisions"}],"predecessor-version":[{"id":10997,"href":"https:\/\/fsxchemical.com\/vi\/wp-json\/wp\/v2\/posts\/10994\/revisions\/10997"}],"wp:attachment":[{"href":"https:\/\/fsxchemical.com\/vi\/wp-json\/wp\/v2\/media?parent=10994"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fsxchemical.com\/vi\/wp-json\/wp\/v2\/categories?post=10994"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fsxchemical.com\/vi\/wp-json\/wp\/v2\/tags?post=10994"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}