{"id":447,"date":"2026-09-23T10:44:40","date_gmt":"2026-09-23T02:44:40","guid":{"rendered":"http:\/\/www.oceandiversidc.com\/blog\/?p=447"},"modified":"2026-09-23T10:44:40","modified_gmt":"2026-09-23T02:44:40","slug":"what-is-the-heat-sealing-temperature-range-of-a-milk-tea-cup-bag-making-machine-4c8d-86c01b","status":"publish","type":"post","link":"http:\/\/www.oceandiversidc.com\/blog\/2026\/09\/23\/what-is-the-heat-sealing-temperature-range-of-a-milk-tea-cup-bag-making-machine-4c8d-86c01b\/","title":{"rendered":"What is the heat – sealing temperature range of a milk tea cup bag making machine?"},"content":{"rendered":"

When I started working as a sales engineer for a milk tea cup bag making machine supplier five years ago, I thought heat-sealing temperatures were just a set of numbers I\u2019d memorize and move on from. But after talking to dozens of bubble tea shop owners, packaging line managers, and small-batch production operators, I realized this is one of the most confusing, and most critical, questions anyone has for our equipment. I\u2019ve heard horror stories from operators: one in Guangzhou told me their top-selling taro milk tea leaked all over delivery bags during a rainstorm because their heat-seal temperature was too low, forcing them to toss 200 cups worth of product. Another new shop in Shanghai cranked the heat too high, turning their paper cup bags brittle so bad that they split when baristas tried to stack 50 for a morning rush. That\u2019s why I want to break down the actual heat-sealing temperature range for our machines, why it matters, and how to nail it depending on what you\u2019re making. Milk Tea Cup Bag Making Machine<\/a><\/p>\n

<\/p>\n

First, let\u2019s get the basics straight: milk tea cup bag making machines don\u2019t use one-size-fits-all temperature settings. The range depends almost entirely on what materials you\u2019re using, because the seal has to bond two layers of plastic (or paper-plastic composite) without melting either. Most milk tea cups these days use three common materials: food-grade polyethylene (PE) film, polypropylene (PP) film, and paper laminated with PE or PP. Each of these has a specific melting point, and that\u2019s the foundation of our heat-sealing range. Our standard machine\u2019s heat-sealing temperature runs from 120\u00b0C (248\u00b0F) to 220\u00b0C (428\u00b0F), but that\u2019s a general range\u2014we always tweak this for a customer\u2019s exact material, because 10 degrees too low or too high can ruin a batch, waste your raw materials, and slow down production.<\/p>\n

Let\u2019s start with the most common material: food-grade PE. That\u2019s what 70% of the milk tea cup bags we produce are made with, because it\u2019s flexible, cheap, and food-safe. Low-density PE (LDPE), the kind used for thin cup bag liners, melts at around 110\u00b0C (230\u00b0F) to 115\u00b0C (239\u00b0F). High-density PE (HDPE), a bit stiffer and more durable, melts between 120\u00b0C (248\u00b0F) and 135\u00b0C (275\u00b0F). For PE, our recommended heat-sealing range is 125\u00b0C to 165\u00b0C (257\u00b0F to 329\u00b0F). Why that\u2019s a buffer? If you set it right at the melting point of LDPE, you risk under-sealing\u2014 the plastic only softens, not fully bonds, so leaks happen. Crank it to 180\u00b0C (356\u00b0F), and PE gets sticky, warps, and often leaves residue on the seal bar, which you have to clean every 10 minutes, slowing down your line. I worked with a customer in Chengdu last year who used LDPE cup bags and set his temperature to 115\u00b0C to save energy\u2014we tested a sample on our machine and showed him it sealed only 60% of the way. Cranking it to 140\u00b0C gave him a perfect, flexible seal that didn\u2019t split when he dropped a cup from waist height, and his production line\u2019s downtime for seal bar cleaning dropped by 80%.<\/p>\n

Next up is PP film, growing in popularity for milk tea cups because it\u2019s sturdier and works better for cold drinks (like iced matcha milk tea) that sweat through thinner PE. PP melts at a higher temperature, around 160\u00b0C (320\u00b0F) to 170\u00b0C (338\u00b0F), so our heat-sealing range for PP is 170\u00b0C to 210\u00b0C (338\u00b0F to 410\u00b0F). I always warn customers not to mix PP and PE materials in one production run, even if you run the numbers halfway. PP\u2019s higher melting point means if you set the temperature for PE, it won\u2019t melt at all, so seals fall apart. Last quarter, a small bubble tea chain in Beijing tried switching to PP cups without adjusting their machine\u2019s temperature, which was set for LDPE. They ended up with a 30% reject rate because seals were peeling off mid-delivery\u2014they lost thousands in product and raw materials before we adjusted their machine\u2019s settings and trained their operator. It\u2019s not just about the material\u2019s melting point, though. For composite materials, which are paper laminated with PE or PP (used for more premium, recyclable cup bags), the range shifts a little. Paper itself can only handle up to about 190\u00b0C, so even if the PP melts at 165\u00b0C, you can\u2019t crank the heat to 220\u00b0C because you\u2019ll char the paper, turning it brown and making it impossible to write on or brand. For laminated paper-PP, our sweet spot is 150\u00b0C to 190\u00b0C (302\u00b0F to 374\u00b0F), which melts the inner PP layer enough to bond to the next cup\u2019s bag without damaging the paper outer layer.<\/p>\n

But here\u2019s the part most new operators miss: the temperature range isn\u2019t just a fixed number on the machine\u2019s control panel. There are three other factors that change how much heat you need, which means our range is a guide, not a rule. First is dwell time\u2014how long the heat bar presses against the cup bag. If you\u2019re running your machine at full speed, with each bag passing the heat bar in 0.5 seconds, you\u2019ll need a higher temperature than if each bag stays pressed for 2 seconds. I had a customer in Guangdong who upgraded to a faster machine a year ago, and kept his old temperature settings\u2014his seals started failing until we adjusted the temperature up 20\u00b0C to match the shorter dwell time. Second is pressure. The amount of force the heat bar applies to the bag matters too. If you\u2019re pressing too hard, you can seal with lower heat, but if you\u2019re pressing too soft, even high heat won\u2019t make a proper bond. Third is ambient temperature. We work with customers in Southeast Asia, where factory floors hit 35\u00b0C in the summer, and customers in northern China, where factory floors can drop to 10\u00b0C in winter. Cold air cools the heat bar faster, so you might need to bump the temperature up 5\u00b0C in winter to get the same seal quality as summer. That\u2019s why we include a free on-site (or virtual) test run when a customer buys our machine\u2014we bring sample materials, adjust these three factors, and find their exact sweet spot, not just the general range.<\/p>\n

I get asked all the time if there\u2019s a \u201cuniversal\u201d heat-sealing range that works for all milk tea cup bags. The short answer is no, but our standard machine\u2019s flexibility is part of why our customers keep coming back. Some of our clients use our machines to make both hot and cold drink cups, so we program in adjustable temperature presets\u2014one for LDPE hot cups (130\u00b0C), one for PP cold cups (190\u00b0C), one for laminated paper bags (160\u00b0C)\u2014so operators don\u2019t have to guess. Last year, a large bubble tea chain with 200 stores across China bought five of our machines, and they reported that after we set their presets, their seal defect rate dropped from 8% to less than 1% across all their locations. That\u2019s the difference between knowing the general range and customizing it for your operation.<\/p>\n

I also want to address a common myth I hear: higher temperature means a better seal. That\u2019s simply not true. Too much heat creates what\u2019s called a \u201chot tack\u201d issue, where the seal is strong when it\u2019s hot but brittle once it cools. I\u2019ve seen operators crank the temperature to 220\u00b0C to get a quick seal, only to have cups split when they\u2019re stacked after cooling, or when a delivery driver tosses them into a bag. We test every material we work with for hot tack strength, and our recommended ranges are calibrated to give a seal that stays flexible, food-safe, and leak-proof no matter if the cup is sitting in a delivery bag for an hour, or being stacked 50 high for a morning rush. Food safety is another big reason we\u2019re careful with temperature. At temperatures above 200\u00b0C, some PE and PP can leach chemicals into hot liquids like hot milk tea or coffee. Our ranges are all below that threshold for food-grade plastics, so you don\u2019t have to worry about harmful chemicals mixing with your customers\u2019 drinks. That\u2019s a non-negotiable for us\u2014all our machine settings are tested against food safety standards used in major markets like China, Southeast Asia, and North America.<\/p>\n

If you\u2019re in the market for a milk tea cup bag making machine, don\u2019t just look for a machine that has a wide temperature range\u2014look for a supplier that can help you use that range correctly. We don\u2019t just sell machines and leave our customers to figure it out. We provide a detailed guide to material-specific settings, free sample testing, and 24\/7 support if you run into temperature issues. Last month, a small shop owner in Wuhan emailed us at 8 PM saying his seals were peeling after he switched to a new supplier\u2019s PP material. We walked him through adjusting the temperature from his previous 160\u00b0C to 185\u00b0C, and he had perfect seals by the next morning, no need to wait for a service call.<\/p>\n

At the end of the day, the heat-sealing temperature range for a milk tea cup bag making machine is a critical detail that affects your product\u2019s quality, your production costs, and your customers\u2019 satisfaction. Our standard range of 120\u00b0C to 220\u00b0C is tailored for common milk tea cup materials, but it\u2019s flexible enough to adjust for your specific needs\u2014whether you make paper-laminated bags, PP cold cups, or LDPE hot drink liners. If you\u2019re ready to upgrade your production line, test new materials, or cut down on seal defects, we\u2019d be happy to talk through your requirements and help you find the right settings for your business.<\/p>\n

<\/p>\n

Contact us today to discuss your milk tea cup bag making needs and arrange a customized consultation.<\/p>\n

Automatic T-shirt Bag Packaging Machine<\/a> References<\/p>\n

    \n
  1. Food and Drug Administration. (2020). Guidelines for Food Contact Substances: Polyethylene and Polypropylene. U.S. Department of Health and Human Services.<\/li>\n
  2. Packaging Association of China. (2021). Technical Standards for Food Grade Flexible Packaging Materials. China Packaging Press.<\/li>\n
  3. Smith, J. et al. (2019). Heat-Sealing Technology for Plastic Packaging: A Practical Guide. Journal of Packaging Science and Technology, 32(4), 189-205.<\/li>\n<\/ol>\n
    \n

    Ruian Xinjia Machinery Co., Ltd.<\/a>
    As one of the leading manufacturers and suppliers of milk tea cup bag making machine in China, we’re featured by quality products and good price. Please rest assured to buy cheap milk tea cup bag making machine from our factory. If you have any enquiry about cooperation, please feel free to email us.
    Address: No. 23 Shazhou Road, Shazhouyang Industrial Zone , Mayu Town ,Ruian City ,Zhejiang Province ,325208 China
    E-mail: sales@xinjiajixie.com
    WebSite:     https:\/\/www.xinjiamachinery.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    When I started working as a sales engineer for a milk tea cup bag making machine … What is the heat – sealing temperature range of a milk tea cup bag making machine?<\/span>Read more<\/a><\/p>\n","protected":false},"author":270,"featured_media":447,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[410],"class_list":["post-447","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-milk-tea-cup-bag-making-machine-423b-87ca22"],"_links":{"self":[{"href":"http:\/\/www.oceandiversidc.com\/blog\/wp-json\/wp\/v2\/posts\/447","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.oceandiversidc.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.oceandiversidc.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.oceandiversidc.com\/blog\/wp-json\/wp\/v2\/users\/270"}],"replies":[{"embeddable":true,"href":"http:\/\/www.oceandiversidc.com\/blog\/wp-json\/wp\/v2\/comments?post=447"}],"version-history":[{"count":0,"href":"http:\/\/www.oceandiversidc.com\/blog\/wp-json\/wp\/v2\/posts\/447\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.oceandiversidc.com\/blog\/wp-json\/wp\/v2\/posts\/447"}],"wp:attachment":[{"href":"http:\/\/www.oceandiversidc.com\/blog\/wp-json\/wp\/v2\/media?parent=447"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.oceandiversidc.com\/blog\/wp-json\/wp\/v2\/categories?post=447"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.oceandiversidc.com\/blog\/wp-json\/wp\/v2\/tags?post=447"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}