{"id":8162,"date":"2026-02-19T09:00:00","date_gmt":"2026-02-19T09:00:00","guid":{"rendered":"https:\/\/uplastech.com\/silicone-kitchenware\/"},"modified":"2026-02-19T09:00:00","modified_gmt":"2026-02-19T09:00:00","slug":"silicone-kitchenware","status":"publish","type":"post","link":"https:\/\/uplastech.com\/it\/silicone-kitchenware\/","title":{"rendered":"Silicone Kitchenware: Heat Resistance Is a Curve, Not a Number"},"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\/silicone-kitchenware.jpg\" alt=\"Pale grey silicone kitchenware on a stainless bench, a flexible spatula, a six-cup muffin mould and a trivet, with a hot-air gun and thermocouple probe\" width=\"1536\" height=\"909\"><figcaption>Spatula, muffin mould and trivet in a stainless tray. All three are the same compound at different thicknesses.<\/figcaption><\/figure>\n<div class=\"toc\"><\/div>\n<h2 id=\"curve\">Nothing fails at a line<\/h2>\n<p>A silicone spatula is usually sold with a number on the pack, 230 C or 250 C, and the number implies a threshold. The material does not have one. It has a curve, and the curve is gentle at first and steep at the end.<\/p>\n<p>Measured as tensile strength retained against temperature, a typical kitchen-grade silicone holds 104 percent at minus 40 C, 100 percent at 23 C, 94 percent at 100 C, 86 percent at 150 C, 72 percent at 200 C and 48 percent at 250 C. There is no cliff; there is a slide that starts around 150 C and accelerates.<\/p>\n<p>That matters because the rating on the pack is a continuous-use temperature, not a failure temperature. A spatula rated at 230 C still has about 55 percent of its strength at that temperature, which is enough to stir a pan and not enough to lever a roast out of a tin. The number describes a working range, not a limit.<\/p>\n<figure>\n<img decoding=\"async\" src=\"https:\/\/uplastech.com\/wp-content\/uploads\/2026\/10\/silicone-kitchenware-chart.jpg\" alt=\"Tensile strength retained falling from 104 percent at minus 40 C to 48 percent at 250 C, and strength after ageing by cure system\" width=\"1536\" height=\"909\"><figcaption>Left: strength retained against temperature, 104 percent cold and 48 percent at 250 C. Right: strength after 70 hours at 225 C, by cure system.<\/figcaption><\/figure>\n<h2 id=\"time\">Time does what temperature does, only slower<\/h2>\n<p>A spatula that sits in a drawer for two years at 25 C has been aged, just not much. A spatula that goes through a dishwasher three times a week has been aged at 70 C in a detergent solution, which is a much harsher exposure than the number suggests.<\/p>\n<p>The two effects combine. Heat at the moment of use softens the material and lowers its strength; heat over time crosslinks or cleaves the network and changes it permanently. A part that is used at 200 C for a minute a day is not the same as one that is aged at 200 C for a week, but both end up on the same curve.<\/p>\n<p>This is why the ageing test is run at a temperature above the use temperature. Seventy hours at 225 C is a stand-in for a much longer period at a lower temperature, and the result is quoted as a percentage of the original strength so that it can be compared across compounds.<\/p>\n<h2 id=\"cure\">The cure system decides what survives<\/h2>\n<p>After 70 hours at 225 C, a peroxide-cured silicone retains 62 percent of its tensile strength, a platinum-cured one 78 percent and a platinum-cured one that has been post-cured 91 percent. That spread is larger than the spread between two different base polymers.<\/p>\n<p>The reason is the same as in any addition-cured system. A peroxide cure leaves a network with a fraction of unreacted sites and ionic residues, and heat attacks those sites. A platinum cure leaves a cleaner network, and post-cure removes the low-molecular-weight fraction that would otherwise volatilise and leave voids.<\/p>\n<p>The practical consequence is that two spatulas that both say 'food grade silicone, 230 C' can differ by a factor of three in how long they last. The rating is a material claim; the cure system and the post-cure are what actually deliver it.<\/p>\n<table>\n<thead>\n<tr>\n<th>Cure system<\/th>\n<th>Strength after 70 h at 225 C<\/th>\n<th>Costo<\/th>\n<th>Utilizzo<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Peroxide<\/td>\n<td>62%<\/td>\n<td>Lowest<\/td>\n<td>Short-life, low-cost lines<\/td>\n<\/tr>\n<tr>\n<td>Platinum<\/td>\n<td>78%<\/td>\n<td>Medio<\/td>\n<td>General kitchenware<\/td>\n<\/tr>\n<tr>\n<td>Platinum + post-cure<\/td>\n<td>91%<\/td>\n<td>Highest<\/td>\n<td>Premium, long-life claims<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 1 \u2014 What is left after ageing, by cure system<\/p>\n<h2 id=\"design\">Thickness changes the answer more than the compound<\/h2>\n<p>A thin spatula blade heats through in seconds and cools in seconds; a thick muffin mould heats slowly and holds its heat. The same compound in a 1 mm blade and a 6 mm mould is not experiencing the same temperature, even in the same oven.<\/p>\n<p>This is why a muffin mould can be rated at 230 C and a thin scraper at 200 C from the same factory. The rating follows the part, not the drum. It also means that a thin part which is left resting on a hot hob will degrade much faster than the rating suggests, because the contact temperature is far above the air temperature.<\/p>\n<p>The design consequence is that thin, flexible parts should be designed to be used briefly and not left in contact with heat, and thick parts can carry a continuous rating. Neither of those is a material property; both are geometry.<\/p>\n<table>\n<thead>\n<tr>\n<th>Part<\/th>\n<th>Typical thickness<\/th>\n<th>Realistic continuous use<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Spatula blade<\/td>\n<td>1-2 mm<\/td>\n<td>200 C, brief contact<\/td>\n<\/tr>\n<tr>\n<td>Spoon or ladle<\/td>\n<td>3-5 mm<\/td>\n<td>220 C<\/td>\n<\/tr>\n<tr>\n<td>Muffin mould<\/td>\n<td>2-3 mm wall<\/td>\n<td>230 C<\/td>\n<\/tr>\n<tr>\n<td>Baking mat<\/td>\n<td>0.6-1 mm<\/td>\n<td>230 C, even heat<\/td>\n<\/tr>\n<tr>\n<td>Handle sleeve<\/td>\n<td>2-3 mm<\/td>\n<td>180 C, no direct contact<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 2 \u2014 Thickness against realistic continuous use<\/p>\n<h2 id=\"failure\">How they actually fail<\/h2>\n<p>The first failure is usually not a break. It is a surface that goes tacky, or a colour that yellows, or a blade that has taken a set and no longer lies flat. All three are the same process: the network is changing and the low-molecular-weight fraction is migrating to the surface.<\/p>\n<p>The second is tearing at a stress concentration. A spatula blade that has lost half its strength will still stir, but it will tear at the junction with the handle, which is where the mould has a sharp internal corner and where the strain is highest.<\/p>\n<p>The third is odour and taste transfer. A part that has been overheated holds volatiles that then transfer to food, and no amount of washing removes them. This is the failure that gets a product returned, and it is invisible until it happens.<\/p>\n<div class=\"myth\">Myth: a higher temperature rating means a longer-lasting product. The rating is a point on a curve. What determines life is the cure system, the post-cure and the thickness, and a well-made 200 C part will outlast a cheap 250 C one.<\/div>\n<h2 id=\"buy\">What to ask a supplier<\/h2>\n<p>Ask for the cure system and the post-cure cycle, not just the temperature rating. Ask for the ageing result, with the temperature and the time, because 70 hours at 225 C and 168 hours at 200 C are different tests and produce different numbers.<\/p>\n<p>Ask what the part is tested against for food contact, and in which simulant. And ask whether the colour is on a platinum-compatible masterbatch, because a colour change can move the part to a different cure system without anyone noticing.<\/p>\n<p>Finally, ask what the realistic continuous-use temperature is for the specific part geometry, not for the compound. A supplier who answers that question has thought about the product; one who quotes the drum data sheet has not.<\/p>\n<div class=\"faq\">\n<h3>Is silicone safe above its rated temperature?<\/h3>\n<p>For brief contact, usually yes, with a loss of strength. Above about 250 C the material starts to decompose and to release volatiles, and that is a different situation from softening.<\/p>\n<h3>Why does my spatula go sticky?<\/h3>\n<p>The network is degrading and low-molecular-weight material is coming to the surface. It is the visible sign of the same ageing that the strength test measures, and it is not reversible.<\/p>\n<h3>Can silicone kitchenware go in the dishwasher?<\/h3>\n<p>Yes, and it will survive many cycles. Detergent at 70 C is a harsher exposure than the same temperature in water, and it accelerates the surface change rather than the bulk strength loss.<\/p>\n<h3>Does colour affect heat resistance?<\/h3>\n<p>Some pigments do. A pigment can act as a catalyst poison in a platinum cure, leaving the part under-cured and less heat resistant, and dark pigments absorb radiant heat faster. A colour change should be re-tested.<\/p>\n<h3>What is the difference between 230 C and 250 C ratings?<\/h3>\n<p>Usually the cure system and the post-cure, not the polymer. A 250 C rating on a platinum-cured, post-cured part is credible; on a peroxide part it is a marketing number.<\/p>\n<h3>How long should silicone kitchenware last?<\/h3>\n<p>A well-made platinum-cured, post-cured part used within its rating should last years of normal use. The failure that ends its life is usually localised overheating, not cumulative ageing.<\/p>\n<\/div>\n<div class=\"cta\">\n<p class=\"cta-h\">Developing a silicone kitchen product?<\/p>\n<p>Send the part drawing and the use case. We will tell you which cure system and post-cure the rating actually requires, and what that costs per unit.<\/p>\n<p><a class=\"btn\" href=\"https:\/\/uplastech.com\/it\/silicone-rubber\/\">Ask about silicone kitchenware<\/a>\n<\/div>\n<div class=\"rel\">\n<h4>Continue reading<\/h4>\n<ul>\n<li><a href=\"https:\/\/uplastech.com\/it\/silicone-post-curing\/\">Silicone Post-Curing: Volatiles, Extractables and the Oven<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/it\/silicone-baby-products\/\">Silicone Baby Products: Volatiles, Extractables and the Post-Cure<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/it\/silicone-hardness-shore-a\/\">Silicone Hardness Shore A: What the Number Does and Does Not Say<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/it\/silicone-compression-molding\/\">Silicone Compression Moulding: Cycle, Flash and Tolerance<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/it\/silicone-rubber\/\">Custom Silicone Rubber: Moulding, Extrusion and Assembly<\/a><\/li>\n<\/ul>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>A silicone spatula rated to 230 C still has 48 percent of its strength left at 250 C. It does not fail at a temperature, it fades along a curve. That changes what the rating means and what the customer should expect after two years in a drawer.<\/p>","protected":false},"author":1,"featured_media":8160,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"Silicone Kitchenware: Heat Resistance and Post-Cure","_seopress_titles_desc":"How silicone kitchenware actually behaves against temperature, why a continuous-use rating is not a failure point, and how the cure system decides what is left","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"39","_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":[39],"tags":[],"class_list":["post-8162","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-silicone-rubber-products"],"meta_box":{"post-to-quiz_to":[]},"_links":{"self":[{"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/posts\/8162","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/comments?post=8162"}],"version-history":[{"count":0,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/posts\/8162\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/media\/8160"}],"wp:attachment":[{"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/media?parent=8162"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/categories?post=8162"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/uplastech.com\/it\/wp-json\/wp\/v2\/tags?post=8162"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}