{"id":7948,"date":"2025-12-09T09:00:00","date_gmt":"2025-12-09T09:00:00","guid":{"rendered":"https:\/\/uplastech.com\/silicone-calendering\/"},"modified":"2025-12-09T09:00:00","modified_gmt":"2025-12-09T09:00:00","slug":"silicone-calendering","status":"publish","type":"post","link":"https:\/\/uplastech.com\/ja\/silicone-calendering\/","title":{"rendered":"Silicone Calendering: Sheet and Coated Fabric in One Pass"},"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-calendering.jpg\" alt=\"Achievable thickness tolerance against target sheet thickness, and cure time against oven temperature\" width=\"1536\" height=\"909\"><figcaption>Tolerance tightens from eight percent on a 0.2 mm sheet to two percent at 2 mm, while cure time drops from 60 seconds at 120 C to 12 at 180 C.<\/figcaption><\/figure>\n<div class=\"toc\"><\/div>\n<h2 id=\"machine\">A calender is four rolls and three gaps<\/h2>\n<p>A calender is a stack of horizontal rolls running at controlled temperatures, with a precise gap between each pair. Silicone compound is fed into the first nip, transferred as a thin band onto the next roll, and reduced at each gap until it leaves the last nip at the target thickness.<\/p>\n<p>The gaps do the metering. There is no die and no screw pumping the material through an orifice, so the output is a continuous sheet whose thickness is set mechanically by the roll separation and the roll speed ratio. That is why calendering can run at 20 to 40 metres a minute and still hold a tolerance that a single-screw extruder cannot.<\/p>\n<p>Roll temperature is the second control. Silicone compound is thixotropic and highly viscous, so it needs to be warm enough to flow into the nip but cool enough not to start curing. Rolls run at 40 to 80 C, well below the cure temperature, and the sheet leaves the last nip as a soft, uncured band.<\/p>\n<h2 id=\"tolerance\">Thickness tolerance follows the target<\/h2>\n<p>The tolerance a calender can hold is a percentage of the target, because it comes from the roll gap and the roll runout rather than from an absolute setting. A 0.2 mm sheet holds about plus or minus 8 percent, a 0.5 mm sheet 5 percent, a 1.0 mm sheet 3.5 percent, a 1.5 mm sheet 2.5 percent and a 2.0 mm sheet 2.0 percent.<\/p>\n<p>In absolute terms that is plus or minus 16 micrometres on the thin sheet and 40 micrometres on the thick one. The thin sheet is harder in relative terms because the same roll runout is a larger fraction of the gap, and because the material has less chance to level out in the last nip.<\/p>\n<p>This is the number that decides whether a sheet can be used for a gasket or a diaphragm. A 0.2 mm silicone sheet at plus or minus 8 percent is plus or minus 16 micrometres, which is fine for a flat gasket but marginal for a diaphragm whose deflection depends on thickness squared. A 1 mm sheet at 3.5 percent is more consistent in absolute terms and is usually the better choice where thickness is functional.<\/p>\n<table>\n<thead>\n<tr>\n<th>Target thickness<\/th>\n<th>Tolerance<\/th>\n<th>Absolute band<\/th>\n<th>Typical use<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>0.2 mm<\/td>\n<td>+\/- 8 percent<\/td>\n<td>+\/- 16 micrometres<\/td>\n<td>Thin gaskets, insulation<\/td>\n<\/tr>\n<tr>\n<td>0.5 mm<\/td>\n<td>+\/- 5 percent<\/td>\n<td>+\/- 25 micrometres<\/td>\n<td>Diaphragms, thin sheeting<\/td>\n<\/tr>\n<tr>\n<td>1.0 mm<\/td>\n<td>+\/- 3.5 percent<\/td>\n<td>+\/- 35 micrometres<\/td>\n<td>General purpose sheet<\/td>\n<\/tr>\n<tr>\n<td>1.5 mm<\/td>\n<td>+\/- 2.5 percent<\/td>\n<td>+\/- 38 micrometres<\/td>\n<td>Seals, pads<\/td>\n<\/tr>\n<tr>\n<td>2.0 mm<\/td>\n<td>+\/- 2.0 percent<\/td>\n<td>+\/- 40 micrometres<\/td>\n<td>Thick sheet, matting<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 1 \u2014 What a calender holds, in percent and in absolute terms.<\/p>\n<h2 id=\"compound\">The compound is not a thermoplastic<\/h2>\n<p>The material on the calender is a high-consistency silicone rubber: a gum base with filler, pigment, and a platinum catalyst plus an inhibitor that holds the cure back at room temperature. It behaves nothing like a thermoplastic melt. It has almost no die swell, it does not freeze on cooling, and it will cure in the machine if the rolls get too warm or if the compound sits too long.<\/p>\n<p>The inhibitor is what makes the process possible. It keeps the compound workable at 40 to 80 C for hours, and it is consumed or driven off at the cure temperature, which is why the sheet can be handled soft and then cured in an oven without a catalyst change. The inhibitor concentration also sets the cure speed, so a compound made for a fast line and one made for a slow line are not interchangeable.<\/p>\n<p>Because the material is uncured when it leaves the calender, the sheet is fragile. It has very little green strength, it marks if it is touched, and it will slump if it is hung. The handling between the last nip and the oven is often the limiting factor on line speed, not the calender itself.<\/p>\n<h2 id=\"fabric\">Coating fabric: the friction coat<\/h2>\n<p>The largest use of silicone calendering is not sheet at all. It is coated fabric, where a thin silicone layer is pressed into a woven or knitted substrate in the same nip. The compound is fed onto the fabric as it enters the gap, and the pressure of the nip forces it into the weave.<\/p>\n<p>This is called friction coating, and it is different from spreading a coating on top. The silicone penetrates the yarns, so the bond is mechanical rather than adhesive, and the result survives flexing and washing that a surface coating would not. A typical coat weight is 100 to 250 grams per square metre on a 200 gram fabric, and the fabric has to be dry and free of size before it enters the nip.<\/p>\n<p>The substrate decides the properties. A polyester fabric gives strength and dimensional stability up to about 150 C, a glass fabric goes higher but is brittle in flex, and a nylon fabric gives the best flex life at moderate temperature. The silicone provides the release, the weather resistance and the temperature range, not the mechanical strength.<\/p>\n<table>\n<thead>\n<tr>\n<th>Substrate<\/th>\n<th>Coat weight<\/th>\n<th>Service temperature<\/th>\n<th>Where it is used<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Polyester woven<\/td>\n<td>100 to 200 g\/m2<\/td>\n<td>Up to 150 C<\/td>\n<td>Flexible ducting, compensators<\/td>\n<\/tr>\n<tr>\n<td>Glass woven<\/td>\n<td>150 to 250 g\/m2<\/td>\n<td>Up to 250 C<\/td>\n<td>Heat shields, expansion joints<\/td>\n<\/tr>\n<tr>\n<td>Nylon woven<\/td>\n<td>100 to 180 g\/m2<\/td>\n<td>Up to 120 C<\/td>\n<td>Inflatable structures, rescue slides<\/td>\n<\/tr>\n<tr>\n<td>Non-woven felt<\/td>\n<td>200 to 400 g\/m2<\/td>\n<td>Up to 200 C<\/td>\n<td>Insulation blankets, seals<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 2 \u2014 Common substrates, coat weights and the service temperature each one allows.<\/p>\n<h2 id=\"cure\">The cure window narrows as it gets hotter<\/h2>\n<p>The sheet leaves the calender uncured and goes into a horizontal or vertical oven. Cure time falls steeply with temperature: 60 seconds at 120 C, 35 seconds at 140 C, 20 seconds at 160 C and 12 seconds at 180 C. That looks like a straightforward speed advantage, and it is, up to a point.<\/p>\n<p>The problem is that the same heat that cures the sheet also drives the inhibitor off and starts the reaction in the compound still on the rolls. At 180 C the sheet cures in 12 seconds, but the process window around that temperature is only a few degrees wide, and a small drift produces either an undercured sheet that is tacky or an overcured one that is brittle and has lost its tear strength.<\/p>\n<p>The practical compromise for most lines is 150 to 165 C. The cure is fast enough to run the calender at its mechanical limit, and the window is wide enough that a normal oven control can hold it. Running at 180 C is done, but usually with a dedicated line, a tighter oven control and a compound formulated for it.<\/p>\n<div class=\"callout\">Cure is not a matter of hitting a temperature. It is a matter of time at temperature, and a sheet that is 5 C cold needs roughly 25 percent more dwell. Measure the cure with a solvent swell or a hardness check, not with the oven display.<\/div>\n<h2 id=\"specify\">What to specify<\/h2>\n<p>Calendered silicone is bought on a handful of numbers, and the ones that cause trouble are the ones buyers leave out.<\/p>\n<ul>\n<li>Thickness and tolerance, quoted in both percent and micrometres.<\/li>\n<li>Hardness in Shore A, and the tolerance on it, usually plus or minus 5 points.<\/li>\n<li>Cure system and the cure state, verified by a solvent swell or a compression set test.<\/li>\n<li>Tensile strength and tear strength, because a calender can hit a thickness and miss the properties.<\/li>\n<li>For coated fabric, the substrate, the yarn count, the coat weight and the adhesion.<\/li>\n<li>Whether the sheet is supplied with a release liner, and which liner.<\/li>\n<\/ul>\n<p>The cure state is the one to insist on. A sheet that is 90 percent cured will pass a visual inspection, feel correct, and fail in service because the compression set is double what it should be. A solvent swell test takes ten minutes and settles it.<\/p>\n<div class=\"faq\">\n<h3>What thickness tolerance can silicone calendering hold?<\/h3>\n<p>About plus or minus 8 percent on a 0.2 mm sheet, 5 percent at 0.5 mm, 3.5 percent at 1.0 mm and 2 percent at 2.0 mm. The tolerance is a percentage because it comes from the roll gap.<\/p>\n<h3>Why is the compound uncured when it leaves the calender?<\/h3>\n<p>Because the rolls run at 40 to 80 C, well below the cure temperature. An inhibitor holds the platinum cure back until the sheet reaches the oven, which is what allows the material to be worked at all.<\/p>\n<h3>What is friction coating?<\/h3>\n<p>Pressing silicone compound into a fabric in the calender nip so that it penetrates the weave. The bond is mechanical, and it survives flexing better than a surface coating.<\/p>\n<h3>What cure temperature should a silicone calender run?<\/h3>\n<p>150 to 165 C for most lines. It is fast enough to keep up with the calender and wide enough for normal oven control. 180 C cures in 12 seconds but leaves only a few degrees of margin.<\/p>\n<h3>Can calendered silicone sheet be used for food contact?<\/h3>\n<p>Yes, with a platinum-cured compound and a post-cure to drive off volatiles. The sheet also has to be tested for extractables, because calendering introduces no solvent but the compound can contain plasticiser.<\/p>\n<h3>How is calendered sheet different from moulded sheet?<\/h3>\n<p>Calendered sheet is continuous and cheaper per square metre, with a tolerance set by the roll gap. Moulded sheet can be thicker and is used where the volume does not justify a calender.<\/p>\n<\/div>\n<div class=\"cta\">\n<p class=\"cta-h\">Need a silicone sheet or a coated fabric to a tight thickness?<\/p>\n<p>Tell us the thickness, the tolerance and the cure state you need to prove. We will quote the calendered route and say whether the tolerance is realistic on the target gauge.<\/p>\n<p><a class=\"btn\" href=\"https:\/\/uplastech.com\/ja\/silicone-rubber-products\/\">Ask about silicone sheet<\/a>\n<\/div>\n<div class=\"rel\">\n<h4>Continue reading<\/h4>\n<ul>\n<li><a href=\"https:\/\/uplastech.com\/ja\/silicone-extrusion-process\/\">Silicone Extrusion: Curing, Tolerances and the Soft Profile<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/ja\/hcr-solid-silicone-rubber\/\">HCR Solid Silicone Rubber: Compound, Milling and Moulding<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/ja\/silicone-compound-formulation\/\">Silicone Compound Formulation: Filler, Catalyst and Inhibitor<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/ja\/medical-grade-silicone\/\">Medical Grade Silicone: What the Certification Actually Covers<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/ja\/food-grade-silicone\/\">Food Grade Silicone: Compliance, Cure and Extractables<\/a><\/li>\n<\/ul>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>A calender holds thickness by the roll gap, not by a die, so a 0.2 mm silicone sheet carries an eight percent tolerance while a 2 mm sheet holds two. Cure time then falls from 60 seconds to 12 as the oven goes from 120 C to 180 C.<\/p>","protected":false},"author":1,"featured_media":7947,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"Silicone Calendering: Sheet, Fabric and Cure","_seopress_titles_desc":"Silicone calendering explained: roll gaps and thickness tolerance by target, why the compound is not a thermoplastic, friction coating onto fabric, the narrowin","_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-7948","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\/ja\/wp-json\/wp\/v2\/posts\/7948","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/uplastech.com\/ja\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/uplastech.com\/ja\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/uplastech.com\/ja\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/uplastech.com\/ja\/wp-json\/wp\/v2\/comments?post=7948"}],"version-history":[{"count":0,"href":"https:\/\/uplastech.com\/ja\/wp-json\/wp\/v2\/posts\/7948\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/uplastech.com\/ja\/wp-json\/wp\/v2\/media\/7947"}],"wp:attachment":[{"href":"https:\/\/uplastech.com\/ja\/wp-json\/wp\/v2\/media?parent=7948"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/uplastech.com\/ja\/wp-json\/wp\/v2\/categories?post=7948"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/uplastech.com\/ja\/wp-json\/wp\/v2\/tags?post=7948"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}