{"id":7326,"date":"2026-10-24T18:28:20","date_gmt":"2026-10-24T17:28:20","guid":{"rendered":"https:\/\/uplastech.com\/pp-injection-molding\/"},"modified":"2026-10-25T04:34:40","modified_gmt":"2026-10-25T04:34:40","slug":"pp-injection-molding","status":"publish","type":"page","link":"https:\/\/uplastech.com\/pl\/pp-injection-molding\/","title":{"rendered":"Custom PP Injection Molding"},"content":{"rendered":"<style>\n.upl-page{font-size:17px;line-height:1.78;color:#1f2937}\n.upl-page p{margin:0 0 18px}\n.upl-page h1{font-size:38px;line-height:1.16;letter-spacing:-.025em;color:#0b2b33;margin:0 0 18px;font-weight:800}\n.upl-page h2{font-size:26px;line-height:1.3;color:#0b2b33;margin:48px 0 14px;font-weight:700;letter-spacing:-.015em}\n.upl-page h3{font-size:19px;color:#0d3b47;margin:26px 0 10px;font-weight:700}\n.upl-page ul,.upl-page ol{margin:0 0 20px;padding-left:22px}\n.upl-page li{margin:0 0 9px}\n.upl-page .lead{font-size:19px;line-height:1.65;color:#4b5563;margin:0 0 36px}\n.upl-page a{color:#0d6b7d}\n.upl-page strong{color:#0b2b33}\n.upl-page .sec-note{font-size:13px;color:#6b7280;margin:-4px 0 26px}\n.upl-page .stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:16px;margin:0 0 20px}\n.upl-page .stat{background:#f7fafb;border:1px solid #e3ebee;border-left:3px solid #14707f;border-radius:8px;padding:16px 20px}\n.upl-page .stat b{display:block;font-size:24px;line-height:1.2;color:#0b2b33;letter-spacing:-.02em;margin-bottom:4px}\n.upl-page .stat span{font-size:12.5px;color:#6b7280;letter-spacing:.04em;text-transform:uppercase;font-weight:600}\n.upl-page .prod-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:26px;margin:0 0 16px}\n.upl-page .prod{background:#fff;border:1px solid #e6ebed;border-radius:12px;overflow:hidden;display:flex;flex-direction:column;scroll-margin-top:96px}\n.upl-page .prod img{width:100%;height:198px;object-fit:cover;display:block;background:#f2f5f6}\n.upl-page .prod .txt{padding:17px 20px 21px;flex:1}\n.upl-page .prod h3{margin:0 0 8px;font-size:17.5px;line-height:1.35;color:#0b2b33}\n.upl-page .prod p{margin:0;font-size:14.5px;color:#5b666b;line-height:1.62}\n.upl-page table{width:100%;border-collapse:collapse;font-size:14.5px;margin:0 0 10px}\n.upl-page th{background:#0d3b47;color:#fff;text-align:left;padding:11px 13px;font-weight:600;font-size:13.5px;border:0}\n.upl-page td{padding:11px 13px;border:0;border-bottom:1px solid #e8ebed;vertical-align:top}\n.upl-page tbody tr:nth-child(even){background:#fafbfc}\n.upl-page .tablecap{font-size:12.5px;color:#6b7280;margin:0 0 30px}\n.upl-page .callout{background:#f2f8f9;border-radius:8px;padding:18px 22px;margin:0 0 26px;font-size:15.5px;border-left:3px solid #14707f}\n.upl-page .faq h3{border-top:1px solid #eceff1;padding-top:22px;margin-top:0;font-size:18px}\n.upl-page .faq h3:first-of-type{border-top:0;padding-top:0}\n.upl-page .cta{background:linear-gradient(135deg,#0b2b33,#0d5563);color:#fff;border-radius:12px;padding:36px;margin:52px 0 20px}\n.upl-page .cta h2{color:#fff;margin:0 0 10px;font-size:25px}\n.upl-page .cta p{color:#c9dee3;margin:0 0 22px;font-size:16px}\n.upl-page .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@media(max-width:640px){.upl-page h1{font-size:28px}.upl-page h2{font-size:22px}.upl-page .prod img{height:180px}.upl-page table{font-size:13px}}\n<\/style>\n<div class=\"upl-page\">\n<p class=\"lead\">Polypropylene is the lightest of the volume thermoplastics and the cheapest per part once you account for density. It shrugs off acids, bases and most solvents, and a properly gated living hinge will flex a million cycles without cracking. The catch is shrinkage of one to two percent and a tendency to warp \u2014 both manageable, but only if the tool is designed for them from the start.<\/p>\n<p>  <img decoding=\"async\" src=\"https:\/\/uplastech.com\/wp-content\/uploads\/2026\/10\/polypropylene-parts.jpg\" alt=\"Custom PP Injection Molding \u2014 Bottle caps and closures\" style=\"width:100%;border-radius:12px;margin:0 0 30px\"><\/p>\n<div class=\"stats\">\n<div class=\"stat\"><b>100 \u2013 110 \u00b0C<\/b><span>HDT at 0.45 MPa<\/span><\/div>\n<div class=\"stat\"><b>25 \u2013 40 MPa<\/b><span>Tensile strength<\/span><\/div>\n<div class=\"stat\"><b style=\"font-size:18px\">0.90 \u2013 0.91 g\/cm\u00b3<\/b><span>G\u0119sto\u015b\u0107<\/span><\/div>\n<\/p><\/div>\n<p class=\"sec-note\">Typical values for standard moulding grades. Exact figures depend on the specific compound or grade \u2014 confirm against your drawing before quoting.<\/p>\n<h2>Key properties<\/h2>\n<table>\n<thead>\n<tr>\n<th>W\u0142asno\u015b\u0107<\/th>\n<th>Typical value<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>G\u0119sto\u015b\u0107<\/td>\n<td>0.90 \u2013 0.91 g\/cm\u00b3<\/td>\n<\/tr>\n<tr>\n<td>Tensile strength<\/td>\n<td>25 \u2013 40 MPa<\/td>\n<\/tr>\n<tr>\n<td>Flexural modulus<\/td>\n<td>1.2 \u2013 1.7 GPa<\/td>\n<\/tr>\n<tr>\n<td>HDT at 0.45 MPa<\/td>\n<td>100 \u2013 110 \u00b0C<\/td>\n<\/tr>\n<tr>\n<td>Mould shrinkage<\/td>\n<td>1.0 \u2013 2.5 %<\/td>\n<\/tr>\n<tr>\n<td>Water absorption (24 h)<\/td>\n<td>&lt; 0.02 %<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Values are typical for unfilled moulding grades at 23 \u00b0C unless stated. Glass-filled and specialty grades differ.<\/p>\n<h2>Typical applications<\/h2>\n<ul>\n<li>Bottle caps and closures<\/li>\n<li>Food containers and thin-wall packaging<\/li>\n<li>Living-hinge lids and flip tops<\/li>\n<li>Automotive battery trays and interior panels<\/li>\n<li>Chemical tanks and laboratory ware<\/li>\n<\/ul>\n<h2>Processing notes<\/h2>\n<ul>\n<li>No drying needed in most cases \u2014 PP absorbs almost no water. Skip the dryer and save a process step.<\/li>\n<li>Melt 200 \u2013 260 \u00b0C, mould 20 \u2013 60 \u00b0C. A cold mould gives the best gloss and the shortest cycle.<\/li>\n<li>Shrinkage of 1.5 % means a 100 mm span moves 1.5 mm. Design ribs and bosses so that differential shrinkage pulls the part flat rather than into a banana.<\/li>\n<li>For living hinges, gate so the melt flows across the hinge line, and keep the hinge thin \u2014 0.25 to 0.4 mm \u2014 with a sharp entry radius.<\/li>\n<\/ul>\n<div class=\"callout\">\n    <strong>Tooling, not just material.<\/strong> Every material above behaves differently in the tool \u2014 shrinkage, gate position, cooling and ejection all change. We review the DFM against the specific grade before the tool is cut, so the first shot is a sample, not a surprise.\n  <\/div>\n<div class=\"faq\">\n<h2>Frequently asked questions<\/h2>\n<h3>Why does my PP part warp even though the tool is correct?<\/h3>\n<p>Almost always differential shrinkage between a thick boss and a thin wall, or uneven cooling between the two halves. Packing profile and mould temperature balance fix it more often than a tool change does.<\/p>\n<h3>Is PP suitable for food contact?<\/h3>\n<p>Yes, in a food-contact grade with the appropriate declaration. We supply the migration documentation your market requires, whether that is EU 10\/2011 or FDA 21 CFR.<\/p>\n<\/p><\/div>\n<h2>Related materials<\/h2>\n<ul class=\"related\">\n<li><a href=\"\/pl\/abs-injection-molding\/\">ABS Injection Molding<\/a><\/li>\n<li><a href=\"\/pl\/pc-injection-molding\/\">PC Injection Molding<\/a><\/li>\n<li><a href=\"\/pl\/pe-injection-molding\/\">PE Injection Molding<\/a><\/li>\n<li><a href=\"\/pl\/nylon-pa-injection-molding\/\">Nylon Injection Molding<\/a><\/li>\n<li><a href=\"\/pl\/pom-acetal-injection-molding\/\">POM Injection Molding<\/a><\/li>\n<li><a href=\"\/pl\/acrylic-pmma-injection-molding\/\">PMMA Acrylic Injection Molding<\/a><\/li>\n<\/ul>\n<p><a href=\"\/pl\/injection-molding\/\">\u2190 All Injection Molding Solutions<\/a><\/p>\n<div class=\"cta\">\n<h2>Send us your PP drawing<\/h2>\n<p>Upload a 3D model or a 2D drawing and we will come back with a DFM review, a tooling cost and a piece price \u2014 usually within two working days.<\/p>\n<p>    <a class=\"btn\" href=\"\/pl\/kontakt\/\">Request a quote<\/a>\n  <\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Polypropylene is the lightest of the volume thermoplastics and the cheapest per part once you account for density. It shrugs off acids, bases and most solvents, and a properly gated living hinge will flex a million cycles without cracking. The catch is shrinkage of one to two percent and a tendency to warp \u2014 both [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_seopress_titles_title":"Custom PP Injection Molding | Uplastech","_seopress_titles_desc":"Custom polypropylene injection moulding for caps, closures, containers and living hinges. 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