{"id":8573,"date":"2026-07-07T09:00:00","date_gmt":"2026-07-07T08:00:00","guid":{"rendered":"https:\/\/uplastech.com\/colour-masterbatch\/"},"modified":"2026-11-02T02:25:13","modified_gmt":"2026-11-02T02:25:13","slug":"colour-masterbatch","status":"publish","type":"post","link":"https:\/\/uplastech.com\/tr\/colour-masterbatch\/","title":{"rendered":"Colour Masterbatch: Carrier Resin, Let-Down Ratio and Dispersion"},"content":{"rendered":"<style>\n.upl-blog{font-size:17px;line-height:1.78;color:#1f2937}\n.upl-blog p{margin:0 0 18px}\n.upl-blog h2{font-size:26px;line-height:1.3;color:#0b2b33;margin:46px 0 14px;font-weight:700;letter-spacing:-.015em}\n.upl-blog h3{font-size:19.5px;color:#0d3b47;margin:28px 0 10px;font-weight:700}\n.upl-blog ul,.upl-blog ol{margin:0 0 20px;padding-left:22px}\n.upl-blog li{margin:0 0 9px}\n.upl-blog figure{margin:0 0 34px}\n.upl-blog figure img{width:100%;height:auto;display:block;border-radius:10px}\n.upl-blog figcaption{font-size:13px;color:#6b7280;margin-top:10px;line-height:1.5}\n.upl-blog .toc{background:none;border:0;border-radius:0;padding:0;margin:0 0 34px}\n.upl-blog .toc .lwptoc{margin:0}\n.upl-blog .toc h4{margin:0 0 10px;font-size:13px;letter-spacing:.1em;text-transform:uppercase;color:#0d5563}\n.upl-blog .toc ol{margin:0;padding-left:18px;font-size:14.5px}\n.upl-blog .toc li{margin-bottom:6px}\n.upl-blog table{width:100%;border-collapse:collapse;font-size:14.5px;margin:0 0 10px}\n.upl-blog th{background:#0d3b47;color:#fff;text-align:left;padding:11px 13px;font-weight:600;font-size:13.5px;border:0}\n.upl-blog td{padding:11px 13px;border:0;border-bottom:1px solid #e8ebed;vertical-align:top}\n.upl-blog tbody tr:nth-child(even){background:#fafbfc}\n.upl-blog .tablecap{font-size:12.5px;color:#6b7280;margin:0 0 30px}\n.upl-blog .myth{background:#fff8ef;border:1px solid #f6ddbd;border-radius:8px;padding:16px 20px;margin:0 0 26px;font-size:15.5px}\n.upl-blog .myth b{color:#a85c10}\n.upl-blog .callout{background:#f2f8f9;border-radius:8px;padding:18px 22px;margin:0 0 26px;font-size:15.5px;border-left:3px solid #14707f}\n.upl-blog .faq h3{border-top:1px solid #eceff1;padding-top:22px;margin-top:0;font-size:18px}\n.upl-blog .faq h3:first-of-type{border-top:0;padding-top:0}\n.upl-blog .cta{background:linear-gradient(135deg,#0b2b33,#0d5563);color:#fff;border-radius:12px;padding:34px;margin:48px 0 30px}\n.upl-blog .cta h2,.upl-blog .cta .cta-h{color:#fff;margin:0 0 10px;font-size:24px;font-weight:700;line-height:1.3}\n.upl-blog .cta p{color:#c9dee3;margin:0 0 20px;font-size:16px}\n.upl-blog .btn{display:inline-block;background:#e07a1f;color:#fff;text-decoration:none;font-weight:700;padding:13px 26px;border-radius:8px;font-size:15.5px}\n.upl-blog .rel{border-top:1px solid #e8ebed;margin-top:40px;padding-top:26px}\n.upl-blog .rel h4{font-size:13px;letter-spacing:.1em;text-transform:uppercase;color:#6b7280;margin:0 0 14px}\n.upl-blog .rel ul{list-style:none;padding:0;margin:0}\n.upl-blog .rel li{padding:11px 0;border-bottom:1px dashed #e8ebed}\n.upl-blog .rel a{text-decoration:none;font-weight:600;font-size:15.5px}\n@media(max-width:640px){.upl-blog h2{font-size:22px}.upl-blog table{font-size:13px}.upl-blog .cta{padding:24px}}\n\/* \u5355\u7bc7\u9875\u9690\u85cf WhatsApp \u95ee\u5019\u5361\uff0c\u53ea\u4fdd\u7559\u5706\u5f62\u6c14\u6ce1\uff0c\u907f\u514d\u906e\u6321\u4fa7\u680f\u8be2\u76d8\u63d0\u4ea4\u6309\u94ae\u3002\n   \u6ce8\u610f\uff1aClick to Chat \u7684\u70b9\u51fb\u903b\u8f91\u662f\u300c\u95ee\u5019\u5361\u5143\u7d20\u5b58\u5728\u5c31\u4e0d\u8df3\u8f6c\u300d\uff0c\u53ea\u9760 CSS \u9690\u85cf\u4f1a\u8ba9\u6c14\u6ce1\u53d8\u6210\u6b7b\u94fe\u63a5\u3002\n   Code Snippets #9\u300cUPL single post: WhatsApp bubble jumps straight to chat\u300d\u8d1f\u8d23\u628a\u8be5\u8282\u70b9\u4ece DOM \u79fb\u9664\uff0c\n   \u4e0b\u9762\u8fd9\u6761 CSS \u53ea\u662f\u79fb\u9664\u524d\u7684\u89c6\u89c9\u515c\u5e95\u3002\u5220 #9 \u524d\u5fc5\u987b\u5148\u5220\u8fd9\u6761\u89c4\u5219\u3002 *\/\nbody.single-post .ht_ctc_chat_greetings_box{display:none !important}\n<\/style>\n<div class=\"upl-blog\">\n<figure>\n<img fetchpriority=\"high\" decoding=\"async\" src=\"https:\/\/uplastech.com\/wp-content\/uploads\/2026\/11\/colour-masterbatch.jpg\" alt=\"Small cylindrical colour masterbatch pellets in two shallow steel trays beside an extruder hopper, one batch deep blue and one natural, on a workshop bench\" width=\"1536\" height=\"909\"><figcaption>The pellet looks uniform. The pigment inside it is what has to disperse.<\/figcaption><\/figure>\n<div class=\"toc\"><\/div>\n<h2 id=\"what\">What is in a masterbatch<\/h2>\n<p>A colour masterbatch is three things: pigment or dye, a carrier resin, and a set of additives that help the pigment wet out and stay dispersed. The pigment is typically 20 to 50 percent by weight. The carrier is the same family as the resin it will be let down into, or a compatible one. The additives are dispersants, waxes and sometimes a stabiliser.<\/p>\n<p>The pellet you buy is not a uniform material. It is a frozen suspension, and the quality of that suspension was decided in a twin screw extruder before the pellet was cut. A well made masterbatch has pigment particles broken down to their primary size and wetted by the carrier, so that when it melts in your machine the pigment is already distributed and only needs to be diluted.<\/p>\n<p>That distinction between dispersion and distribution is the key to most colour problems. Distribution is mixing: spreading the pigment evenly through the melt. Dispersion is breaking up the agglomerates into individual particles. Your extruder screw does distribution well and dispersion badly, because it does not generate enough local shear. If the masterbatch arrives with undispersed agglomerates, they will still be there in the product as specks.<\/p>\n<p>This is why the masterbatch supplier's dispersion quality matters more than the pigment loading. Two masterbatches at the same loading can behave completely differently in the same machine, and the difference is not visible in the certificate. It shows up as specks, as streaks or as a colour that reads differently under different lighting.<\/p>\n<h2 id=\"carrier\">The carrier has to match the resin<\/h2>\n<p>The carrier is the reason a masterbatch has a recommended resin family on the label. A carrier that is compatible with the base resin melts at a similar temperature, has a similar viscosity and bonds to the base resin across the interface. When it does, the masterbatch disperses and the colour is uniform. When it does not, the carrier forms discrete domains and the colour is patchy no matter how long you mix.<\/p>\n<p>The chart on the left shows the consequence. A matched carrier holds the colour difference under the visible limit of one dE all the way to a 50 to 1 let-down. A universal carrier crosses that limit at about 33 to 1. A wrong carrier is already visible at 10 to 1 and reaches four and a half dE at 50 to 1, which is a different colour, not a shade variation.<\/p>\n<figure>\n<img decoding=\"async\" src=\"https:\/\/uplastech.com\/wp-content\/uploads\/2026\/11\/colour-masterbatch-chart.jpg\" alt=\"Colour difference rising with let-down ratio for three carrier systems, with the visible limit of one dE marked, plus a bar chart of colour problem sources\" width=\"1536\" height=\"909\"><figcaption>Left: a matched carrier holds the shade; a wrong one does not. Right: what causes colour problems.<\/figcaption><\/figure>\n<p>Universal masterbatches are a real product and they work, within limits. They use a carrier with broad compatibility, often an EVA or a low molecular weight olefin blend, and they trade dispersion quality and let-down ratio for flexibility. For short runs, for colour trials or for a plant that runs many resins through one line, that trade is worth making. For a long production run in one resin, a matched carrier is better in every dimension except inventory.<\/p>\n<p>PVC, PET and polyamide are the three families where the carrier question becomes critical. PVC needs a plasticiser-compatible carrier and cannot tolerate a polyolefin one at all. PET needs a low melting carrier and a dried masterbatch, because moisture in the carrier hydrolyses the base resin. Polyamide needs a carrier that can survive the drying and the melt temperature, which rules out most polyolefin carriers.<\/p>\n<table>\n<thead>\n<tr>\n<th>Base resin<\/th>\n<th>Carrier to specify<\/th>\n<th>What goes wrong otherwise<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>PE, PP<\/td>\n<td>Same polyolefin, LLDPE or PP based<\/td>\n<td>Little; universal carriers work to about 30:1<\/td>\n<\/tr>\n<tr>\n<td>PVC<\/td>\n<td>Plasticiser based, phthalate or citric<\/td>\n<td>Carrier does not fuse, colour is streaky and dull<\/td>\n<\/tr>\n<tr>\n<td>PET<\/td>\n<td>Low melting polyester, dried<\/td>\n<td>Hydrolysis, IV drop, colour shifts dark<\/td>\n<\/tr>\n<tr>\n<td>PA, PA6, PA66<\/td>\n<td>Polyamide carrier, dried<\/td>\n<td>Blistering, weak weld lines, colour mottling<\/td>\n<\/tr>\n<tr>\n<td>ABS, PC<\/td>\n<td>Styrenic or polycarbonate carrier<\/td>\n<td>Surface streaks, gloss difference at the gate<\/td>\n<\/tr>\n<tr>\n<td>PMMA<\/td>\n<td>Acrylic carrier<\/td>\n<td>Haze, loss of clarity in transparent parts<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 1 \u2014 Match the carrier to the resin, not to the colour<\/p>\n<h2 id=\"letdown\">Let-down ratio and why 2 percent is not universal<\/h2>\n<p>Let-down ratio is the ratio of base resin to masterbatch, so 25 to 1 means one part masterbatch to twenty five parts resin, which is four percent. The number is set by the pigment loading in the masterbatch and by how strong the colour needs to be, and it is a property of the pair rather than a universal rule.<\/p>\n<p>The reason two percent is quoted so often is that it is a convenient dosing rate for a volumetric feeder and it works for many standard colours at 30 to 40 percent pigment loading. It is not a specification. A white masterbatch at 50 percent titanium dioxide might need 5 percent to be opaque, while a black at 40 percent carbon black might need 1 percent to be black.<\/p>\n<p>The practical constraint is dosing accuracy. A volumetric feeder at 2 percent has an error of perhaps plus or minus 0.2 percent, which is ten percent of the dose and a visible colour difference. The same feeder at 5 percent has the same absolute error, which is four percent of the dose and invisible. Low let-down ratios amplify every dosing error, which is why a colour that is difficult to hold usually needs a more concentrated masterbatch, not a less concentrated one.<\/p>\n<p>Gravimetric dosing removes most of this problem by weighing the masterbatch rather than metering its volume, and it also records what was actually used. For any colour where a dE of one matters, gravimetric dosing pays for itself in reduced giveaway and fewer rejects. The chart's steep curve for a wrong carrier is the same shape as the curve for a badly dosed correct one.<\/p>\n<h2 id=\"dispersion\">Dispersion: the part you cannot see until it fails<\/h2>\n<p>Undispersed pigment shows up in three ways, and only one of them is a colour problem. The first is specks: visible particles of agglomerate in an otherwise uniform surface. The second is streaks: lines of concentrated colour running in the flow direction, typical of a masterbatch that melted later than the base resin. The third is a strength loss, which appears in a thin section or a weld line and has nothing to do with colour at all.<\/p>\n<p>The strength loss is the one that gets missed. An agglomerate is a stress concentration. In a thin wall, a fibre-filled compound or a part that sees impact, an undispersed particle is a crack initiation site, and the part fails at a lower load than the design assumed. A black speck in a cosmetic part is a reject; the same speck in a structural part is a field failure.<\/p>\n<p>The fix is upstream. Ask the masterbatch supplier for a dispersion rating, measured by a filter pressure test or a microscopy count, and specify a maximum agglomerate size for critical parts. In the plant, the things that help are a mixing section in the screw, adequate back pressure, and a melt temperature high enough to actually melt the carrier. A machine running cold to protect the polymer will not disperse a masterbatch.<\/p>\n<p>Screens and filters are a diagnostic as well as a fix. A screen pack that blinds quickly, or a pressure rise that is faster than the base resin alone would cause, is telling you the masterbatch is carrying undispersed material. Recording the pressure rise per tonne of compound is a cheap and sensitive dispersion test.<\/p>\n<h2 id=\"testing\">Testing colour and agreeing a tolerance<\/h2>\n<p>Colour is measured as a difference, not as an absolute. A spectrophotometer reads the sample, compares it to a standard under a defined illuminant and geometry, and reports the difference in L, a and b. The single number dE combines the three into a distance, and the standard for visible difference in most industrial work is about one.<\/p>\n<p>The measurement conditions have to be agreed or the numbers are not comparable. Which illuminant, D65 or A. Which observer, two or ten degrees. Which geometry, specular included or excluded. Whether the sample is a plaque, a chip or the finished part. Two labs measuring the same part under different conditions can disagree by more than the tolerance, and neither is wrong.<\/p>\n<p>The standard itself should be a physical sample, not a number. A colour that exists only as a set of L, a, b values cannot be checked against a supplier's plaque, and the plaque will drift with age and light. Keep a master plaque in the dark, replace it on a schedule, and record the date on it so nobody is comparing against a faded reference.<\/p>\n<p>Metamerism is the trap at the end of this process. Two colours can match under D65 and differ under tungsten, because their spectral curves cross. For any product that will be seen under more than one light source, measure under at least two and set a limit on the difference between them. A colour that is approved in the office and wrong in the shop is a metameric match, not a bad batch.<\/p>\n<table>\n<thead>\n<tr>\n<th>Let-down ratio<\/th>\n<th>Pigment in masterbatch<\/th>\n<th>Typical use<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>50:1 (2 %)<\/td>\n<td>20 to 30 %<\/td>\n<td>Pale tints, low cost, wide dosing tolerance needed<\/td>\n<\/tr>\n<tr>\n<td>33:1 (3 %)<\/td>\n<td>30 to 40 %<\/td>\n<td>Standard colours, the common default<\/td>\n<\/tr>\n<tr>\n<td>25:1 (4 %)<\/td>\n<td>35 to 45 %<\/td>\n<td>Strong or dark colours, tight colour control<\/td>\n<\/tr>\n<tr>\n<td>20:1 (5 %)<\/td>\n<td>40 to 50 %<\/td>\n<td>Opacified white, high hiding power<\/td>\n<\/tr>\n<tr>\n<td>10:1 (10 %)<\/td>\n<td>50 %+<\/td>\n<td>Very dark or highly loaded, short runs<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 2 \u2014 Ratio and loading move together<\/p>\n<h2 id=\"dosing\">Dosing hardware and keeping it honest<\/h2>\n<p>A volumetric feeder is a screw or a disc that delivers a fixed volume per revolution. It is simple, cheap and adequate for a stable colour at a high let-down rate. Its weakness is that the bulk density of a masterbatch varies between batches, so the same volume is a different mass, and the colour moves with the density rather than with the setting.<\/p>\n<p>A gravimetric feeder weighs the masterbatch as it doses and corrects the screw speed to hold the target rate. It costs more and it holds colour to a fraction of the variation. It also produces a record, which is the part that matters when a customer asks why one pallet is a shade different from another. For any colour where dE 1.0 is a real limit, the record is worth as much as the accuracy.<\/p>\n<p>Where the feeder sits matters too. Dosing onto the screw throat with the base resin gives good premixing. Dosing downstream, into a side feeder on a twin screw, gives better dispersion for difficult pigments but needs a machine designed for it. Adding masterbatch by hand at the hopper is acceptable for a trial and unacceptable for production, because the dose is whatever the operator scoops.<\/p>\n<p>The last piece is the check that the dose is what the setting says. Weigh a sample of the finished product, compare its colour against the standard, and compare the masterbatch consumption against the production weight. If the plant used four kilos of masterbatch to make a tonne of product, the dose was 4 percent regardless of what the feeder display says.<\/p>\n<div class=\"faq\">\n<h3>Why does my colour look different on a different machine?<\/h3>\n<p>Almost always dispersion rather than the masterbatch. A machine with a shorter screw, lower back pressure or a colder barrel does not break down the agglomerates, so the same masterbatch gives a different colour. Check melt temperature and back pressure before changing the masterbatch.<\/p>\n<h3>Can I use a universal masterbatch for everything?<\/h3>\n<p>For short runs and colour trials, yes. Above about 30 to 1 let-down the colour difference becomes visible, and in PVC, PET or polyamide the carrier may not be compatible at all. Match the carrier for production.<\/p>\n<h3>What is a normal let-down ratio?<\/h3>\n<p>Between 20 to 1 and 50 to 1, which is 2 to 5 percent. The number is set by the pigment loading in the masterbatch and by the colour you need, not by a universal rule. Low ratios need better dosing accuracy.<\/p>\n<h3>Why are there specks in my coloured parts?<\/h3>\n<p>Undispersed pigment agglomerates. The masterbatch arrived with them or the machine did not melt the carrier fully. Raise melt temperature and back pressure, add a mixing section, and ask the supplier for a dispersion rating.<\/p>\n<h3>How do I set a colour tolerance?<\/h3>\n<p>Agree the illuminant, the observer, the geometry and the sample form, then set a maximum dE, usually 1.0. Keep a physical master plaque in the dark as the reference, and check metamerism under a second light source.<\/p>\n<h3>Do I need a gravimetric feeder for colour?<\/h3>\n<p>If the colour has to hold within dE 1.0, yes. Volumetric feeders vary with bulk density between batches and produce no record. Gravimetric dosing holds the rate and gives you the evidence when a customer asks.<\/p>\n<\/div>\n<div class=\"cta\">\n<p class=\"cta-h\">Colour that drifts between batches or between machines?<\/p>\n<p>Send the colour standard, the resin and the let-down ratio you are using. We will tell you whether it is the carrier, the dispersion or the dosing.<\/p>\n<p><a class=\"btn\" href=\"https:\/\/uplastech.com\/tr\/plasti%cc%87k-ekstruzyon-cozumleri%cc%87\/\">Ask about colour masterbatch<\/a>\n<\/div>\n<div class=\"rel\">\n<h4>Continue reading<\/h4>\n<ul>\n<li><a href=\"https:\/\/uplastech.com\/tr\/profile-colour-matching\/\">Profile Colour Matching: Getting the Shade Right First Time<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/colour-streaks-injection-molding\/\">Colour Streaks in Injection Moulding: Causes and Fixes<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/extrusion-gravimetric-dosing\/\">Gravimetric Dosing on an Extrusion Line<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/sheet-surface-gloss\/\">Sheet Surface Gloss: What Controls It and What Does Not<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/coextrusion-adhesion\/\">Coextrusion Adhesion: Why the Layers Separate<\/a><\/li>\n<\/ul>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>A masterbatch is a pigment dispersed in a carrier resin, and the carrier is the part that decides whether the colour arrives evenly, at the ratio you planned, in the resin you are actually running.<\/p>","protected":false},"author":1,"featured_media":8572,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17],"tags":[],"class_list":["post-8573","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-plastic-extrusion-process"],"meta_box":{"post-to-quiz_to":[]},"_links":{"self":[{"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/posts\/8573","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/comments?post=8573"}],"version-history":[{"count":1,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/posts\/8573\/revisions"}],"predecessor-version":[{"id":8587,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/posts\/8573\/revisions\/8587"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/media\/8572"}],"wp:attachment":[{"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/media?parent=8573"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/categories?post=8573"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/tags?post=8573"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}