{"id":7756,"date":"2025-09-15T09:00:00","date_gmt":"2025-09-15T08:00:00","guid":{"rendered":"https:\/\/uplastech.com\/polystyrene-thermoforming\/"},"modified":"2025-09-15T09:00:00","modified_gmt":"2025-09-15T08:00:00","slug":"polystyrene-thermoforming","status":"publish","type":"post","link":"https:\/\/uplastech.com\/tr\/polystyrene-thermoforming\/","title":{"rendered":"Polystyrene Thermoforming: GPPS, HIPS and the Brittleness Problem"},"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\/polystyrene-thermoforming.jpg\" alt=\"Clear GPPS cups and white HIPS trays on a thin-gauge thermoforming line\" width=\"1536\" height=\"909\"><figcaption>Polystyrene is the cheapest transparent pack in the world and the one most likely to arrive cracked. Both facts come from the same molecular structure.<\/figcaption><\/figure>\n<div class=\"toc\"><\/div>\n<h2 id=\"why\">Why polystyrene still owns the disposable pack<\/h2>\n<p>Polystyrene has been under environmental pressure for a decade and it is still one of the highest-volume thin-gauge materials in the world. The reason is not inertia. It is that PS does four things at once better and cheaper than anything else.<\/p>\n<p>It is transparent without additives. It is stiff enough that a 0.4 mm wall behaves like a structural part. It absorbs almost no water, so it does not need drying and the cycle can run in seconds. And it takes print, adhesive and heat sealing without surface treatment.<\/p>\n<p>Those four properties come from a rigid, non-polar, amorphous chain. The same rigidity is what makes it brittle, and the same non-polarity is what makes it cheap to dry. PS is a package deal: you cannot keep the advantages and remove the weakness.<\/p>\n<table>\n<thead>\n<tr>\n<th>M\u00fclkiyet<\/th>\n<th>Why it matters in thin gauge<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Amorphous, clear<\/td>\n<td>No crystallisation haze, no drying for clarity<\/td>\n<\/tr>\n<tr>\n<td>High stiffness (E \u2248 3200 MPa)<\/td>\n<td>Thin walls hold shape; less material per pack<\/td>\n<\/tr>\n<tr>\n<td>Moisture absorption 0.02 \u2013 0.05%<\/td>\n<td>No dryer, no hydrolysis, cycle measured in seconds<\/td>\n<\/tr>\n<tr>\n<td>Low specific heat<\/td>\n<td>Heats and cools fast \u2014 the fastest thin-gauge cycle of any common material<\/td>\n<\/tr>\n<tr>\n<td>Good printability<\/td>\n<td>Solvent and UV inks wet out without corona treatment<\/td>\n<\/tr>\n<tr>\n<td>Low cost<\/td>\n<td>Cheapest of the clear packaging polymers<\/td>\n<\/tr>\n<tr>\n<td>Brittle<\/td>\n<td>The one weakness, and it decides the wall thickness<\/td>\n<\/tr>\n<tr>\n<td>Service limit about 75 \u00b0C<\/td>\n<td>Rules out hot fill and microwave<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 1 \u2014 What polystyrene brings to a thin-gauge line. The first six rows are why it survives, the last two are why it is being replaced.<\/p>\n<p>The cycle advantage is larger than it sounds. Because PS needs no drying and has a low specific heat, a thin-gauge PS line can run at 6 to 12 cycles per minute where a PET line of the same geometry runs at 5 to 8, and a PP line at 4 to 6. On a commodity pack with a cent of margin, that difference decides the quote.<\/p>\n<h2 id=\"grades\">GPPS and HIPS are different products<\/h2>\n<p>\"Polystyrene\" covers two materials that behave differently enough to be treated as separate specifications.<\/p>\n<p>GPPS \u2014 general purpose polystyrene \u2014 is the homopolymer. It is water-clear, stiff, and brittle. It is what a clear deli lid, a disposable cup and a transparent blister are made of.<\/p>\n<p>HIPS \u2014 high impact polystyrene \u2014 is GPPS with 5 to 12% polybutadiene rubber grafted in. The rubber particles absorb impact by initiating many small crazes instead of one crack, which raises impact strength by a factor of five to ten and turns the material opaque white. It is what a refrigerator liner, a yoghurt pot and an electronics tray are made of.<\/p>\n<table>\n<thead>\n<tr>\n<th>M\u00fclkiyet<\/th>\n<th>GPPS<\/th>\n<th>HIPS<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>G\u00f6r\u00fcn\u00fc\u015f<\/td>\n<td>Water clear<\/td>\n<td>Opaque white to ivory<\/td>\n<\/tr>\n<tr>\n<td>Butadiene content<\/td>\n<td>0<\/td>\n<td>5 \u2013 12%<\/td>\n<\/tr>\n<tr>\n<td>Yo\u011funluk<\/td>\n<td>1.05 g\/cm\u00b3<\/td>\n<td>1.04 \u2013 1.05 g\/cm\u00b3<\/td>\n<\/tr>\n<tr>\n<td>Notched Izod<\/td>\n<td>15 \u2013 25 J\/m<\/td>\n<td>80 \u2013 150 J\/m<\/td>\n<\/tr>\n<tr>\n<td>Tensile modulus<\/td>\n<td>3200 MPa<\/td>\n<td>1800 \u2013 2200 MPa<\/td>\n<\/tr>\n<tr>\n<td>Forming temperature<\/td>\n<td>130 \u2013 160 \u00b0C<\/td>\n<td>140 \u2013 170 \u00b0C<\/td>\n<\/tr>\n<tr>\n<td>K\u00fc\u00e7\u00fclme<\/td>\n<td>0.4 \u2013 0.6%<\/td>\n<td>0.4 \u2013 0.7%<\/td>\n<\/tr>\n<tr>\n<td>Service limit<\/td>\n<td>70 \u00b0C<\/td>\n<td>75 \u00b0C<\/td>\n<\/tr>\n<tr>\n<td>Relative cost<\/td>\n<td>1.0<\/td>\n<td>1.15 \u2013 1.30<\/td>\n<\/tr>\n<tr>\n<td>Typical pack<\/td>\n<td>Clear lid, cup, blister<\/td>\n<td>Tray, pot, electronics insert<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 2 \u2014 GPPS against HIPS. The impact difference is a factor of five; the stiffness difference runs the other way.<\/p>\n<p>The trade is stiffness against toughness, and it is not a small trade in either direction. A HIPS tray is about 40% less stiff than the same geometry in GPPS, which means it needs a thicker wall or a rib to carry the same load. Designers who switch from GPPS to HIPS for impact resistance often find they have to add 20% material, and the cost advantage of the tougher grade disappears.<\/p>\n<h2 id=\"drying\">Almost no drying, which is why the cycle is fast<\/h2>\n<p>The moisture absorption of PS is 0.02 to 0.05%, roughly a hundredth of PET and a tenth of PMMA. That single number is why a PS line does not have a dryer, and why it can start up in ten minutes where a PET line needs four hours.<\/p>\n<table>\n<thead>\n<tr>\n<th>Malzeme<\/th>\n<th>Equilibrium moisture<\/th>\n<th>Drying required<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>PS, HIPS<\/td>\n<td>0.02 \u2013 0.05%<\/td>\n<td>None in normal conditions<\/td>\n<\/tr>\n<tr>\n<td>PP<\/td>\n<td>Under 0.02%<\/td>\n<td>None<\/td>\n<\/tr>\n<tr>\n<td>PVC (rigid)<\/td>\n<td>0.1 \u2013 0.3%<\/td>\n<td>Sometimes, for clarity<\/td>\n<\/tr>\n<tr>\n<td>PMMA<\/td>\n<td>0.3 \u2013 0.4%<\/td>\n<td>Yes, before forming<\/td>\n<\/tr>\n<tr>\n<td>PET, APET<\/td>\n<td>0.4%<\/td>\n<td>Yes \u2014 hydrolysis risk<\/td>\n<\/tr>\n<tr>\n<td>PC<\/td>\n<td>0.15 \u2013 0.35%<\/td>\n<td>Yes \u2014 bubbles and haze<\/td>\n<\/tr>\n<tr>\n<td>PA<\/td>\n<td>1.5 \u2013 3.0%<\/td>\n<td>Yes, mandatory<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 3 \u2014 Moisture absorption by material. PS and PP are the two that genuinely do not need a dryer.<\/p>\n<p>The exception is a PS sheet that has been stored in an unheated warehouse through a humid season. Condensation on the sheet surface, rather than absorption into it, will produce bubbles and a mottled appearance on the formed part. That is a storage problem rather than a drying problem, and the fix is to let the roll come to room temperature in its wrapper before opening it \u2014 not to install a dryer.<\/p>\n<h2 id=\"brittle\">The brittleness problem<\/h2>\n<p>Everything difficult about PS thin-gauge packaging traces back to one property. GPPS has a notched impact strength of 15 to 25 J\/m, which is roughly a tenth of HIPS and a fortieth of polycarbonate. A 0.4 mm GPPS wall will crack from a knock that a 0.4 mm PP wall would not notice.<\/p>\n<p>This shows up as a cluster of complaints that all sound different and are all the same problem: lids that crack at the rim when they are snapped on, trays that split at the corner when they are demoulded, packs that arrive broken after a pallet drop, and blisters that crack at the hanger hole in retail.<\/p>\n<table>\n<thead>\n<tr>\n<th>Symptom<\/th>\n<th>Where the stress comes from<\/th>\n<th>Fix<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Crack at the rim on closing<\/td>\n<td>Interference fit too tight<\/td>\n<td>Open the fit 0.1 mm, add a radius<\/td>\n<\/tr>\n<tr>\n<td>Split at a corner on demould<\/td>\n<td>Sharp internal radius<\/td>\n<td>Radius to at least one wall thickness<\/td>\n<\/tr>\n<tr>\n<td>Breakage in transit<\/td>\n<td>Wall too thin, or nesting too tight<\/td>\n<td>Thicker wall, looser nesting<\/td>\n<\/tr>\n<tr>\n<td>Crack at the hanger hole<\/td>\n<td>Stress concentration at the hole edge<\/td>\n<td>Reinforcing boss, or move the hole<\/td>\n<\/tr>\n<tr>\n<td>Crazing after printing<\/td>\n<td>Solvent attack plus residual stress<\/td>\n<td>Anneal before printing, milder solvent<\/td>\n<\/tr>\n<tr>\n<td>Crack at a heat seal<\/td>\n<td>Seal temperature too high, brittle seal<\/td>\n<td>Lower seal temperature, longer dwell<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 4 \u2014 Brittle failure modes in PS packaging. Five of the six are geometry, not material.<\/p>\n<p>The good news is that most of these are design fixes rather than material changes. A GPPS part with generous radii, an even wall and a wall thickness above about 0.35 mm performs acceptably in most packaging applications. A GPPS part with sharp corners and a 0.25 mm wall will fail regardless of how carefully it is handled.<\/p>\n<p>The demould crack is worth a specific note because it is often blamed on the sheet. A part that cracks as it leaves the mould was formed at too low a temperature, so the material was still stiff when the mould pushed it, and the stress was locked in at the corner. Raising the sheet temperature by 10 \u00b0C fixes it, and the operator usually tries three other things first.<\/p>\n<h2 id=\"process\">Forming parameters<\/h2>\n<table>\n<thead>\n<tr>\n<th>Parametre<\/th>\n<th>GPPS<\/th>\n<th>HIPS<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Sheet temperature<\/td>\n<td>130 \u2013 155 \u00b0C<\/td>\n<td>140 \u2013 165 \u00b0C<\/td>\n<\/tr>\n<tr>\n<td>Mould temperature<\/td>\n<td>20 \u2013 45 \u00b0C<\/td>\n<td>25 \u2013 50 \u00b0C<\/td>\n<\/tr>\n<tr>\n<td>Vacuum<\/td>\n<td>\u22120.5 to \u22120.7 bar<\/td>\n<td>\u22120.5 to \u22120.7 bar<\/td>\n<\/tr>\n<tr>\n<td>Plug assist<\/td>\n<td>Usually needed above 0.8 : 1 draw<\/td>\n<td>Usually needed above 0.7 : 1<\/td>\n<\/tr>\n<tr>\n<td>Draw ratio limit<\/td>\n<td>1.5 : 1<\/td>\n<td>1.3 : 1<\/td>\n<\/tr>\n<tr>\n<td>\u00c7evrim s\u00fcresi<\/td>\n<td>2 \u2013 5 s<\/td>\n<td>3 \u2013 6 s<\/td>\n<\/tr>\n<tr>\n<td>Shrinkage allowance<\/td>\n<td>0.5%<\/td>\n<td>0.55%<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 5 \u2014 Forming settings. HIPS needs a slightly hotter sheet and has a lower draw limit because the rubber phase softens earlier.<\/p>\n<p>PS forms at a lower temperature than any other common thin-gauge material, which is both an advantage and a trap. The advantage is a short heat cycle and low energy cost. The trap is that a heater set for PET will crystallise nothing but will overheat PS to the point where it sags into the oven and the sheet touches the elements.<\/p>\n<p>The draw ratio limit for PS is generous compared with PP, because the material has good melt strength and does not sag. A 1.5 to 1 cup is routine in GPPS, which is why the disposable cup industry is built on it.<\/p>\n<h2 id=\"secondary\">Static, print and the secondary operations<\/h2>\n<p>PS takes secondary operations better than most packaging materials, and three of them are effectively free.<\/p>\n<p><strong>Printing.<\/strong> GPPS and HIPS both accept solvent-based and UV-cured inks without corona treatment, because the surface energy is already around 40 mN\/m. A PS cup printed six colours inline is standard; the same job on PP needs flame or corona treatment first.<\/p>\n<p><strong>Heat sealing.<\/strong> PS seals to itself and to coated board at 130 to 160 \u00b0C, which is low enough that the seal does not distort the part. This is why PS is the default for blister packs on printed card.<\/p>\n<p><strong>Anti-static.<\/strong> Plain PS has a surface resistivity of 10\u00b9\u00b2 to 10\u00b9\u2074 \u03a9, which is enough to hold a dust film and enough to damage an unprotected PCB. An anti-static grade brings it to 10\u2079 to 10\u00b9\u00b9 \u03a9, and for electronics packaging it is not optional.<\/p>\n<table>\n<thead>\n<tr>\n<th>Operation<\/th>\n<th>PS performance<\/th>\n<th>Note<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Solvent \/ UV print<\/td>\n<td>Excellent, no treatment<\/td>\n<td>Surface energy about 40 mN\/m<\/td>\n<\/tr>\n<tr>\n<td>Heat seal to coated card<\/td>\n<td>Excellent, 130 \u2013 160 \u00b0C<\/td>\n<td>The blister standard<\/td>\n<\/tr>\n<tr>\n<td>RF \/ ultrasonic seal<\/td>\n<td>\u0130yi<\/td>\n<td>Used for cups and lids<\/td>\n<\/tr>\n<tr>\n<td>Anti-static grade<\/td>\n<td>Available, 10\u2079 \u2013 10\u00b9\u00b9 \u03a9<\/td>\n<td>Required for electronics<\/td>\n<\/tr>\n<tr>\n<td>Die cutting<\/td>\n<td>M\u00fckemmel<\/td>\n<td>Brittle, so it cuts cleanly<\/td>\n<\/tr>\n<tr>\n<td>Solvent bonding<\/td>\n<td>Good with DCM or toluene<\/td>\n<td>Rarely used in packaging<\/td>\n<\/tr>\n<tr>\n<td>Hot filling<\/td>\n<td>Not possible above 75 \u00b0C<\/td>\n<td>Rules out hot fill entirely<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 6 \u2014 Secondary operations. The die cutting row is the flip side of brittleness: PS cuts beautifully because it does not stretch.<\/p>\n<h2 id=\"replace\">Where PS is being replaced, and where it is not<\/h2>\n<p>Legislation in a number of markets has pushed single-use PS out of food service, and the substitution is not uniform.<\/p>\n<p><strong>Hot food and hot drink.<\/strong> PS is genuinely unsuitable and always was. PP has replaced it on the merits, not because of regulation.<\/p>\n<p><strong>Cold food containers.<\/strong> PP and PET have taken share. PP wins on toughness and heat resistance, PET on clarity and recyclability. PS keeps the very low-cost end where stiffness matters more than either.<\/p>\n<p><strong>Electronics trays.<\/strong> PS has largely held, because HIPS plus anti-static is a combination that is cheap, dimensionally stable and easy to mould into a complex nest. The alternatives cost more and do not print as well.<\/p>\n<p><strong>Medical and diagnostic.<\/strong> GPPS is still used for clear diagnostic housings and pipette trays, where the requirement is optical clarity plus dimensional stability and the volume does not justify a tool in another material.<\/p>\n<p>The honest summary is that PS is losing the high-visibility food service applications and holding the invisible industrial ones. A converter who only reads the trade press would think the material was disappearing; a converter who looks at the order book sees a stable industrial base and a shrinking consumer one.<\/p>\n<div class=\"faq\">\n<h3>What is the difference between GPPS and HIPS?<\/h3>\n<p>GPPS is clear, stiff and brittle. HIPS has 5\u201312% butadiene rubber grafted in, which makes it opaque white, five to ten times tougher in impact, and about 40% less stiff.<\/p>\n<h3>Does polystyrene need drying before forming?<\/h3>\n<p>Normally no. PS absorbs 0.02\u20130.05% moisture, which is a hundredth of PET. The exception is a cold roll brought into a humid shop \u2014 let it reach room temperature inside its wrapper before opening.<\/p>\n<h3>Why does my PS part crack when it comes out of the mould?<\/h3>\n<p>The sheet was too cold. Forming a stiff sheet forces the material into the corner and locks in stress, which releases as a crack on demould. Raise the sheet temperature by 10 \u00b0C.<\/p>\n<h3>Can polystyrene be microwaved?<\/h3>\n<p>No. The service limit is about 75 \u00b0C, and a microwave will exceed that. Use PP or CPET for anything that has to be reheated.<\/p>\n<h3>What draw ratio can PS handle?<\/h3>\n<p>About 1.5 to 1 in GPPS and 1.3 to 1 in HIPS, which is generous compared with PP. The disposable cup industry is built on GPPS at that ratio.<\/p>\n<h3>Can PS be recycled?<\/h3>\n<p>Technically yes, and GPPS and HIPS are both mechanically recyclable. Practically, collection rates for post-consumer PS packaging are low and many markets have restricted single-use PS food service, so recycled content is hard to source.<\/p>\n<h3>How do I make PS packaging anti-static?<\/h3>\n<p>Specify an anti-static grade, which brings surface resistivity from 10\u00b9\u00b2\u201310\u00b9\u2074 \u03a9 down to 10\u2079\u201310\u00b9\u00b9 \u03a9. For electronics packaging this is a requirement, not a preference.<\/p>\n<h3>Why does PS print better than PP?<\/h3>\n<p>Its surface energy is already around 40 mN\/m, so ink wets out without treatment. PP sits at about 31 mN\/m and needs flame or corona treatment before anything will adhere.<\/p>\n<\/div>\n<div class=\"cta\">\n<p class=\"cta-h\">Running PS, HIPS or a switch away from it?<\/p>\n<p>Send the pack drawing and tell us whether it sees heat, whether it carries electronics and what happens if it cracks. We will tell you whether PS is still the right answer and what the wall thickness has to be.<\/p>\n<p><a class=\"btn\" href=\"https:\/\/uplastech.com\/tr\/custom-vacuum-forming\/\">Talk to a thin-gauge thermoforming engineer<\/a>\n<\/div>\n<div class=\"rel\">\n<h4>Continue reading<\/h4>\n<ul>\n<li><a href=\"https:\/\/uplastech.com\/tr\/pet-rpet-thermoforming\/\">PET and rPET Thermoforming: Crystallinity and the Forming Window<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/pp-thin-gauge-thermoforming\/\">PP Thin-Gauge Thermoforming: Shrinkage and Warpage<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/blister-packaging-design\/\">Blister Packaging Design<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/thick-gauge-vs-thin-gauge-thermoforming\/\">Thick Gauge vs Thin Gauge Thermoforming<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/vacuum-forming-defects-troubleshooting\/\">Vacuum Forming Defects: Troubleshooting<\/a><\/li>\n<\/ul>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>The cheapest clear pack in the world and the one most likely to arrive cracked. Why PS needs no dryer, and the six places brittleness shows up in a design.<\/p>","protected":false},"author":1,"featured_media":7749,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"Polystyrene Thermoforming: GPPS, HIPS and the Brittleness Pr","_seopress_titles_desc":"The cheapest clear pack in the world and the one most likely to arrive cracked. 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