{"id":7747,"date":"2025-09-13T09:00:00","date_gmt":"2025-09-13T08:00:00","guid":{"rendered":"https:\/\/uplastech.com\/coextrusion-layer-adhesion\/"},"modified":"2025-09-13T09:00:00","modified_gmt":"2025-09-13T08:00:00","slug":"coextrusion-layer-adhesion","status":"publish","type":"post","link":"https:\/\/uplastech.com\/pt\/coextrusion-layer-adhesion\/","title":{"rendered":"Coextrusion Layer Adhesion: Why Layers Delaminate and How to Test"},"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\/10\/coextrusion-layer-adhesion.jpg\" alt=\"Coextruded multi-layer profile cross section under a peel test with layers separating\" width=\"1536\" height=\"909\"><figcaption>Two polymers will flow together perfectly and still come apart in service. Adhesion is a separate problem from coextrusion.<\/figcaption><\/figure>\n<div class=\"toc\"><\/div>\n<h2 id=\"why\">Why two polymers will not stick<\/h2>\n<p>Coextrusion is easy to describe and hard to do well. Two or more melts are brought together in a die, flow as a single stream, and leave as one piece. They bond because they are both molten and in intimate contact, and for a small number of polymer pairs that is genuinely all it takes.<\/p>\n<p>For most pairs it is not. Polymers are mutually insoluble, and two melts in contact will form a weak boundary layer unless there is some specific interaction between them. The relevant measure is the solubility parameter, \u03b4, expressed in (cal\/cm\u00b3)<sup>\u00bd<\/sup>. When two polymers have similar \u03b4 values they tend to be compatible; when the difference is large they are not, and the interface between them has essentially no strength.<\/p>\n<table>\n<thead>\n<tr>\n<th>Polymer<\/th>\n<th>\u03b4 (cal\/cm\u00b3)<sup>\u00bd<\/sup><\/th>\n<th>Notas<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>PE<\/td>\n<td>7.9<\/td>\n<td>Non-polar, low surface energy<\/td>\n<\/tr>\n<tr>\n<td>PP<\/td>\n<td>8.1<\/td>\n<td>Close enough to PE to bond<\/td>\n<\/tr>\n<tr>\n<td>PS<\/td>\n<td>9.1<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>PMMA<\/td>\n<td>9.3<\/td>\n<td>Bonds to PVC and PC<\/td>\n<\/tr>\n<tr>\n<td>PVC<\/td>\n<td>9.5<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>PC<\/td>\n<td>9.8<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>PET<\/td>\n<td>10.7<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>EVOH<\/td>\n<td>12.5<\/td>\n<td>Barrier layer, always needs a tie<\/td>\n<\/tr>\n<tr>\n<td>PA6<\/td>\n<td>13.6<\/td>\n<td>Highly polar, bonds to almost nothing<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 1 \u2014 Solubility parameters. A difference under about 1 gives a bond; above 2 the interface has no strength.<\/p>\n<p>The rule of thumb is that a \u03b4 difference below about 1 (cal\/cm\u00b3)<sup>\u00bd<\/sup> gives a usable bond, 1 to 2 is marginal and needs help, and above 2 the two layers will peel apart with almost no force.<\/p>\n<p>That single table explains most of the coextrusion industry. PE and PP differ by 0.2 and bond directly. PMMA and PVC differ by 0.2 and bond directly, which is why acrylic-capped PVC profile is a standard product. PE and PA6 differ by 5.7, which is why every PA\/PE structure in the world needs a tie layer.<\/p>\n<h2 id=\"three\">Three cases: compatible, incompatible, and tied<\/h2>\n<p>Every coextruded structure falls into one of three categories, and knowing which one you are in decides the whole design.<\/p>\n<table>\n<thead>\n<tr>\n<th>Case<\/th>\n<th>Exemplo<\/th>\n<th>What it needs<\/th>\n<th>Peel strength<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Compatible<\/td>\n<td>PE\/PP, PMMA\/PVC, PS\/PMMA<\/td>\n<td>Correct interface temperature only<\/td>\n<td>2 \u2013 6 N\/15mm, cohesive<\/td>\n<\/tr>\n<tr>\n<td>Marginal<\/td>\n<td>PC\/PMMA, PET\/PC<\/td>\n<td>Temperature and residence time control<\/td>\n<td>1 \u2013 3 N\/15mm<\/td>\n<\/tr>\n<tr>\n<td>Incompatible<\/td>\n<td>PE\/PA, PE\/EVOH, PP\/PET<\/td>\n<td>A tie layer, no alternative<\/td>\n<td>Fails without one<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 2 \u2014 The three cases. The middle case is the one that fails intermittently and is hardest to diagnose.<\/p>\n<p>The marginal case is the dangerous one because it works often enough to pass a trial. PC and PMMA will bond at a high enough interface temperature, and the bond will be adequate on a thick section running slowly and will fail on a thin section running fast, because the interface never got hot enough. If a structure is marginal, the process window has to be established by peel testing across the range, not at one set of conditions.<\/p>\n<p>For an incompatible pair there is no process window at all. A tie layer is a thin layer of a polymer that is compatible with both sides, usually a polyolefin grafted with maleic anhydride. The anhydride groups react with the polar groups on the PA or EVOH side, and the polyolefin backbone entangles with the PE side. The tie layer is typically 10 to 25 \u00b5m, and it is the reason a five-layer barrier film works.<\/p>\n<table>\n<thead>\n<tr>\n<th>Structure<\/th>\n<th>Layers<\/th>\n<th>Fun\u00e7\u00e3o<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>PE \/ tie \/ EVOH \/ tie \/ PE<\/td>\n<td>5<\/td>\n<td>Barrier packaging film<\/td>\n<\/tr>\n<tr>\n<td>PE \/ tie \/ PA \/ tie \/ PE<\/td>\n<td>5<\/td>\n<td>Thermoformable barrier, pouch<\/td>\n<\/tr>\n<tr>\n<td>PP \/ tie \/ EVOH \/ tie \/ PP<\/td>\n<td>5<\/td>\n<td>Retort and hot-fill<\/td>\n<\/tr>\n<tr>\n<td>PMMA \/ PVC<\/td>\n<td>2<\/td>\n<td>Weathering cap on window profile<\/td>\n<\/tr>\n<tr>\n<td>PE \/ PP<\/td>\n<td>2<\/td>\n<td>Soft-touch surface on a rigid core<\/td>\n<\/tr>\n<tr>\n<td>PMMA \/ ABS<\/td>\n<td>2<\/td>\n<td>Gloss cap on a structural substrate<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 3 \u2014 Common coextruded structures. Every five-layer structure exists because of a \u03b4 mismatch that a tie layer bridges.<\/p>\n<h2 id=\"peel\">The peel test, and what the number means<\/h2>\n<p>Adhesion is measured by peeling the layers apart at a controlled angle and speed, and reporting the force per unit width. The unit is N\/15 mm in packaging and N\/cm in industrial profile work, and the two are not interchangeable without care.<\/p>\n<p>The test standard matters more than people expect. T-peel, 90\u00b0 peel and 180\u00b0 peel give different numbers for the same bond, and peel speed changes the result for a viscoelastic material. A specification that says \"peel strength above 3 N\/15mm\" without a standard and a speed is not a specification.<\/p>\n<table>\n<thead>\n<tr>\n<th>Aplica\u00e7\u00e3o<\/th>\n<th>Typical requirement<\/th>\n<th>Note<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>General packaging film<\/td>\n<td>2.5 \u2013 3.5 N\/15 mm<\/td>\n<td>Below 2 the layer can delaminate in handling<\/td>\n<\/tr>\n<tr>\n<td>Retort \/ pasteurised pouch<\/td>\n<td>4 \u2013 6 N\/15 mm<\/td>\n<td>Heat and steam attack the interface<\/td>\n<\/tr>\n<tr>\n<td>Barrier tie layer<\/td>\n<td>Above 6 N\/15 mm, cohesive<\/td>\n<td>The tie should tear, not peel<\/td>\n<\/tr>\n<tr>\n<td>Pipe with a barrier layer<\/td>\n<td>Above 5 N\/cm<\/td>\n<td>Ring bending stresses the interface<\/td>\n<\/tr>\n<tr>\n<td>Weathering cap on profile<\/td>\n<td>Above 4 N\/cm<\/td>\n<td>Thermal cycling over years<\/td>\n<\/tr>\n<tr>\n<td>Soft-touch overmould<\/td>\n<td>Above 3 N\/cm<\/td>\n<td>Handling and cleaning<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 4 \u2014 Peel strength targets. The tie layer row is the important one: a good tie does not peel, it tears.<\/p>\n<p>The distinction between adhesive and cohesive failure is the most useful diagnostic in the whole subject. An adhesive failure separates cleanly at the interface: the peel force is low and one surface is mirror-smooth. A cohesive failure tears through one of the layers: the force is high and both surfaces are rough with polymer.<\/p>\n<p>A tie layer that fails cohesively is working correctly. The interface bond is stronger than the tie layer itself, so the tear goes through the weakest bulk material, which is what you want. A tie layer that fails adhesively at 1 N\/15mm is not doing its job, and the cause is almost always process rather than material.<\/p>\n<div class=\"callout\">\n<p><strong>Read the failure surface, not just the number.<\/strong> A 4 N\/15mm cohesive peel is a good bond. A 4 N\/15mm adhesive peel is a bond that is about to fail in service.<\/p>\n<\/div>\n<h2 id=\"process\">The process variables that actually set adhesion<\/h2>\n<p>Given a compatible or tied pair, adhesion is set by four things, and they are all about the interface rather than about the bulk.<\/p>\n<table>\n<thead>\n<tr>\n<th>Vari\u00e1vel<\/th>\n<th>Effect<\/th>\n<th>Practical direction<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Interface temperature<\/td>\n<td>Diffusion rate across the boundary<\/td>\n<td>Raise until both layers are above their melting range<\/td>\n<\/tr>\n<tr>\n<td>Contact time in the die<\/td>\n<td>How long diffusion has to happen<\/td>\n<td>Longer die land, lower line speed<\/td>\n<\/tr>\n<tr>\n<td>Interfacial shear<\/td>\n<td>Renews the interface, strips oxide and low-MW skin<\/td>\n<td>Some shear helps; too much causes instability<\/td>\n<\/tr>\n<tr>\n<td>Layer thickness ratio<\/td>\n<td>Thin layer cools faster, less diffusion time<\/td>\n<td>Keep the thin layer above its freezing point<\/td>\n<\/tr>\n<tr>\n<td>Contamina\u00e7\u00e3o<\/td>\n<td>Low-MW material, dust, release agent at the boundary<\/td>\n<td>Clean resin, no release agent in the outer layer<\/td>\n<\/tr>\n<tr>\n<td>Moisture<\/td>\n<td>Steam at the interface, bubbles and no bond<\/td>\n<td>Dry PA, EVOH, PET properly<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 5 \u2014 Process levers for adhesion. Interface temperature and contact time are the two that matter most.<\/p>\n<p>Interface temperature is the dominant variable, and it is not the same as either melt temperature. It is the temperature the two melts reach when they meet, which depends on both streams, on the die body temperature, and on how far the combined stream travels before it freezes. A die that is running hot on both extruders but has a cold zone at the combining point will produce a weak bond, and the extruder temperatures will look perfect.<\/p>\n<p>Contact time is the second lever and it is usually the one with no room to move. The die land length is fixed by the tool, and the line speed is fixed by the economics. What can change is the temperature, which is why raising the die temperature is the standard fix for a weak bond \u2014 and why it often brings its own problem, which is that the low-viscosity layer starts to migrate and the layer thicknesses drift.<\/p>\n<p>Interfacial shear is the subtle one. A small amount of shear at the boundary breaks up the stagnant layer and brings fresh polymer into contact, which improves the bond. Too much shear produces interfacial instability \u2014 the wavy, uneven layer thickness known as zig-zag or wave instability \u2014 and the bond becomes uneven along the length. This is why the die design and the viscosity match between layers matter: the two melts should have similar viscosities at the combining point, or the interface will be unstable no matter what the temperature is.<\/p>\n<h2 id=\"fail\">Failure modes and what they mean<\/h2>\n<table>\n<thead>\n<tr>\n<th>Symptom<\/th>\n<th>Likely cause<\/th>\n<th>Where to look<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Clean peel at low force<\/td>\n<td>Interface too cold, or incompatible pair without a tie<\/td>\n<td>Die temperature at the combining point<\/td>\n<\/tr>\n<tr>\n<td>Bond good at start of run, fails later<\/td>\n<td>Die zone drifting, or a cold spot building up<\/td>\n<td>Die temperature log over the shift<\/td>\n<\/tr>\n<tr>\n<td>Bubbles along the interface<\/td>\n<td>Moisture in the polar layer<\/td>\n<td>Dryer dew point, not the die<\/td>\n<\/tr>\n<tr>\n<td>Wavy layer thickness<\/td>\n<td>Viscosity mismatch, interfacial instability<\/td>\n<td>Melt temperature and viscosity of each stream<\/td>\n<\/tr>\n<tr>\n<td>Delamination in service, not at test<\/td>\n<td>Bond adequate but not aged; thermal cycling opens it<\/td>\n<td>Peel test after heat ageing<\/td>\n<\/tr>\n<tr>\n<td>Bond strong in the middle, weak at edges<\/td>\n<td>Edge cooling in the die, or die lip damage<\/td>\n<td>Die lip and edge heating<\/td>\n<\/tr>\n<tr>\n<td>Tie layer peels off with the substrate<\/td>\n<td>Tie chemistry wrong for the substrate<\/td>\n<td>Grade selection, not process<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 6 \u2014 Adhesion failures. The fourth row is a rheology problem that no temperature change will fix.<\/p>\n<p>The heat-ageing point is the one that catches packaging converters. A bond that measures 5 N\/15mm on the day of production can measure 1.5 N\/15mm after a week at 40 \u00b0C, because the interface continues to relax and any residual stress concentrates there. Retort structures are tested after the retort cycle for exactly this reason, and a specification that only tests the as-made film is testing the wrong thing.<\/p>\n<p>Edge weakness is a die problem that looks like a material problem. The edges of a coextruded stream cool faster than the centre, so the interface at the edge is colder and the bond is weaker. On a wide die this shows up as a film that delaminates from the edges inward, and the fix is edge heating or a die lip that is not over-cooled.<\/p>\n<h2 id=\"spec\">Specifying adhesion properly<\/h2>\n<p>Adhesion is the property most often left off a coextrusion specification, and it is the one that decides whether the product survives its service life.<\/p>\n<p>A usable specification names the test standard, the peel angle and speed, the specimen width, the conditioning, and whether the requirement applies before or after ageing. It also names the failure mode expected, because a cohesive peel at 3 N\/15mm is a better product than an adhesive peel at 5 N\/15mm.<\/p>\n<p>For a barrier structure, the requirement should be stated after the most severe condition the product will see \u2014 retort, pasteurisation, or a heat-ageing cycle \u2014 not as-made. For an outdoor profile with a weathering cap, it should be stated after thermal cycling, because a cap that peels after two winters is the failure mode that matters.<\/p>\n<p>It is also worth specifying the tie layer grade and thickness, because these are the two variables a converter can quietly change to save money. A 25 \u00b5m tie replaced with a 12 \u00b5m tie of a cheaper grade will still pass a hand peel and will fail a heat-aged peel test.<\/p>\n<div class=\"faq\">\n<h3>Why do my two layers not stick?<\/h3>\n<p>Either the polymers are incompatible \u2014 a solubility parameter difference above 2, like PE and PA \u2014 or the interface temperature is too low. Check the material pair first, then the die temperature at the combining point.<\/p>\n<h3>What is a tie layer and when do I need one?<\/h3>\n<p>A thin layer of a polymer compatible with both sides, usually a maleic anhydride grafted polyolefin. You need one whenever the two main layers differ by more than about 2 in solubility parameter \u2014 PE\/EVOH and PE\/PA are the classic cases.<\/p>\n<h3>What peel strength should I specify?<\/h3>\n<p>2.5\u20133.5 N\/15 mm for general packaging, 4\u20136 N\/15 mm for retort, and above 6 N\/15 mm cohesive for a barrier tie layer. Always name the test standard, the peel angle and whether the requirement applies after ageing.<\/p>\n<h3>Why does the bond fail only at the edges?<\/h3>\n<p>The edges of the coextruded stream cool faster, so the interface there is colder and diffusion is slower. It is a die edge-heating problem, not a material problem.<\/p>\n<h3>What causes wavy layer thickness?<\/h3>\n<p>Interfacial instability from a viscosity mismatch between the layers. The two melts need similar viscosities at the combining point, and the shear rate has to stay below the point where the interface breaks up.<\/p>\n<h3>Can PE and PA be coextruded without a tie?<\/h3>\n<p>No. Their solubility parameters differ by 5.7, so the interface has essentially no strength. Every PE\/PA structure uses a tie layer, and the tie has to be the right grade for the PA.<\/p>\n<h3>Why do bubbles appear along the interface?<\/h3>\n<p>Moisture in the polar layer. PA, EVOH and PET all absorb water, and at melt temperature it flashes to steam exactly at the boundary where the two streams meet. Check the dryer dew point, not the die.<\/p>\n<h3>Does a thicker tie layer give a stronger bond?<\/h3>\n<p>Only up to a point. The bond strength is set by the interface, not by the bulk of the tie, and a tie above about 25 \u00b5m adds cost without adding peel strength. What a thicker tie does buy is tolerance to process variation.<\/p>\n<\/div>\n<div class=\"cta\">\n<p class=\"cta-h\">Building a coextruded profile with a cap or a barrier layer?<\/p>\n<p>Tell us the layer structure, the substrate and what the part has to survive \u2014 weather, retort, chemical exposure. We will tell you whether the pair bonds directly, what tie layer it needs, and what peel strength is realistic.<\/p>\n<p><a class=\"btn\" href=\"https:\/\/uplastech.com\/pt\/custom-plastic-extrusion-profiles-guide\/\">Talk to a coextrusion engineer<\/a>\n<\/div>\n<div class=\"rel\">\n<h4>Continue reading<\/h4>\n<ul>\n<li><a href=\"https:\/\/uplastech.com\/pt\/co-extrusion-profiles\/\">Co-Extrusion Profiles: Materials and Design<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/pt\/packaging-tube-barrier-coextrusion\/\">Barrier Coextrusion for Packaging Tubes<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/pt\/extrusion-die-design\/\">Extrusion Die Design<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/pt\/pvc-profile-welding-fabrication\/\">PVC Profile Welding and Fabrication<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/pt\/defeitos-de-extrusao-de-plastico\/\">Plastic Extrusion Defects and Their Causes<\/a><\/li>\n<\/ul>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Two melts flow together perfectly and still peel apart. Solubility parameter, tie layers, the four process variables that set bond strength, and how to write a peel spec.<\/p>","protected":false},"author":1,"featured_media":7740,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"Coextrusion Layer Adhesion: Why Layers Delaminate and How to","_seopress_titles_desc":"Two melts flow together perfectly and still peel apart. Solubility parameter, tie layers, the four process variables that set bond strength, and how to wri","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"36","_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":"coextrusion layer adhesion","footnotes":""},"categories":[17,36],"tags":[],"class_list":["post-7747","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-plastic-extrusion-process","category-profile-extrusion"],"meta_box":{"post-to-quiz_to":[]},"_links":{"self":[{"href":"https:\/\/uplastech.com\/pt\/wp-json\/wp\/v2\/posts\/7747","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/uplastech.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/uplastech.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/uplastech.com\/pt\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/uplastech.com\/pt\/wp-json\/wp\/v2\/comments?post=7747"}],"version-history":[{"count":0,"href":"https:\/\/uplastech.com\/pt\/wp-json\/wp\/v2\/posts\/7747\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/uplastech.com\/pt\/wp-json\/wp\/v2\/media\/7740"}],"wp:attachment":[{"href":"https:\/\/uplastech.com\/pt\/wp-json\/wp\/v2\/media?parent=7747"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/uplastech.com\/pt\/wp-json\/wp\/v2\/categories?post=7747"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/uplastech.com\/pt\/wp-json\/wp\/v2\/tags?post=7747"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}