{"id":3710,"date":"2026-09-09T01:26:13","date_gmt":"2026-09-09T01:26:13","guid":{"rendered":"https:\/\/szfilmfactory.com\/?p=3710"},"modified":"2026-09-21T02:19:36","modified_gmt":"2026-09-21T02:19:36","slug":"coefficient-of-friction-in-bopp-film","status":"publish","type":"post","link":"https:\/\/szfilmfactory.com\/ru\/blog\/coefficient-of-friction-in-bopp-film\/","title":{"rendered":"Coefficient of Friction (COF) in BOPP Film Explained"},"content":{"rendered":"<p class=\"wp-block-paragraph\"><strong>The coefficient of friction (COF) in BOPP film measures how easily one film surface slides against another surface.<\/strong> A lower COF means easier sliding, while a higher COF means more resistance. For BOPP film, the right COF is important for stable feeding, winding, packaging, lamination, and other converting processes.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What Does COF Mean in BOPP Film?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>COF is a numerical value that describes the friction between two surfaces.<\/strong> It is usually expressed as a ratio between the friction force and the normal force.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The basic formula is:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>COF = Friction Force \/ Normal Force<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A lower COF usually means the film slides more easily. A higher COF provides more resistance to sliding.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In BOPP film, COF can be measured between:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Film and film<\/li>\n\n\n\n<li>Film and metal<\/li>\n\n\n\n<li>Film and other materials used in processing<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The actual COF value depends on the film formulation, surface treatment, additives, temperature, pressure, and testing conditions.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Why Is COF Important for BOPP Film?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>COF directly affects how BOPP film runs during converting and packaging.<\/strong> The wrong COF can cause feeding problems, unstable film movement, poor stacking, or processing delays.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For example, a film with a very low COF may slide too easily during certain operations. A film with a high COF may create too much resistance during high-speed feeding or film handling.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is why COF should not be judged as simply \u201chigh\u201d or \u201clow.\u201d <strong>The right COF depends on the final application and production equipment.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For packaging films, COF can affect:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Film feeding and machine speed<\/li>\n\n\n\n<li>Bag making and wrapping<\/li>\n\n\n\n<li>Film stacking<\/li>\n\n\n\n<li>Winding performance<\/li>\n\n\n\n<li>Lamination and converting<\/li>\n\n\n\n<li>Automatic packaging stability<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Need help selecting the right BOPP film? <strong><a href=\"https:\/\/szfilmfactory.com\/ru\/contact\/\" target=\"_blank\" rel=\"noreferrer noopener\">Shunzhan New Materials <\/a>can provide technical testing reports to help customers choose a film with a suitable COF for their application.<\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Static COF vs. Kinetic COF<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Static COF measures the resistance before the film starts moving, while kinetic COF measures the resistance while the film is already sliding.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">These two values provide different information.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Static COF<\/strong> shows how difficult it is to start sliding.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Kinetic COF<\/strong> shows how much resistance exists during continuous sliding.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Both values can be useful when evaluating BOPP film for automated packaging or converting equipment. A stable relationship between static and kinetic COF can help support smoother film movement.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What Affects the COF of BOPP Film?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>COF is affected by both the film surface and the processing environment.<\/strong> The same BOPP film may show different results under different conditions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Important factors include:<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Film Additives<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Slip additives can reduce surface friction and lower COF.<\/strong> This is common in films that need easier handling and faster machine feeding.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Surface Treatment<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong><a href=\"https:\/\/szfilmfactory.com\/ru\/blog\/bopp-film-corona-treatment-decay-solutions\/\" target=\"_blank\" rel=\"noreferrer noopener\">Corona treatment<\/a> and other surface processes can change surface properties and influence COF.<\/strong> The effect depends on the film structure and treatment level.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Temperature and Humidity<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Testing conditions can affect COF results.<\/strong> Film surfaces may behave differently under different temperature and humidity conditions.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Counter Surface<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>COF changes depending on what the BOPP film is sliding against.<\/strong> Film-to-film COF and film-to-metal COF are not necessarily the same.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Aging and Storage<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Film properties can change after production and during storage.<\/strong> Additive migration and environmental exposure may affect the final surface behavior.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For this reason, COF test results should always be reviewed together with the test method and conditions.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How Is BOPP Film COF Tested?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>BOPP film COF is commonly tested by sliding one material against another under controlled conditions.<\/strong> A typical test measures the force needed to start and maintain sliding.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The test report may include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Static COF<\/li>\n\n\n\n<li>Kinetic COF<\/li>\n\n\n\n<li>Test material or counter surface<\/li>\n\n\n\n<li>Test temperature<\/li>\n\n\n\n<li>Humidity<\/li>\n\n\n\n<li>Test direction<\/li>\n\n\n\n<li>Sample condition<\/li>\n\n\n\n<li>Test standard<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>A COF number is meaningful only when its testing conditions are also understood.<\/strong> Two films should not be compared only by their COF values if they were tested under different conditions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">At Shunzhan New Materials, we can provide <strong>technical testing reports<\/strong> to support film selection and help customers evaluate whether a specific COF is suitable for their application.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How to Choose the Right COF for BOPP Film<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>The best COF is the one that matches the application, machine, and final product requirements.<\/strong> There is no single COF value that is ideal for every BOPP film.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For example, high-speed packaging may require good film slip to support smooth feeding. Other applications may need more surface resistance for better handling or stacking.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">When selecting a BOPP film, consider:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>What is the film application?<\/strong><\/li>\n\n\n\n<li><strong>What surface will the film contact?<\/strong><\/li>\n\n\n\n<li><strong>What machine speed and process are used?<\/strong><\/li>\n\n\n\n<li><strong>Is film slip or surface grip more important?<\/strong><\/li>\n\n\n\n<li><strong>What COF range has been proven on the customer&#8217;s equipment?<\/strong><\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Our team can use technical test data to help customers select a suitable film structure and COF.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">COF and BOPP Film Products<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>COF requirements can vary between different BOPP film applications.<\/strong> For example, packaging and heat-sealing applications may have different surface and processing requirements.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Shunzhan New Materials<\/strong> specializes in <strong>BOPP and PET films<\/strong>, including film solutions for packaging and converting applications. Depending on the project, customers can also review products such as <strong>BOPP heat seal film<\/strong> and other functional film options.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For technical parameters, our website also provides a <strong><a href=\"https:\/\/szfilmfactory.com\/ru\/film-tds-technical-data-sheets\/\" target=\"_blank\" rel=\"noopener\">TDS summary page<\/a><\/strong> where you can compare key film specifications and use the available technical data as a reference before making a selection.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Choose BOPP Film with the Right COF<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Choosing the right COF can improve film handling and reduce problems during production.<\/strong> Instead of selecting a film based on COF alone, it is better to evaluate COF together with the application, film structure, machine conditions, and test data.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Shunzhan New Materials<\/strong> can provide <strong><a href=\"https:\/\/szfilmfactory.com\/ru\/film-tds-technical-data-sheets\/\" target=\"_blank\" rel=\"noreferrer noopener\">technical testing reports and product data<\/a><\/strong> to help customers identify a suitable BOPP film for their process.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Need help with BOPP film selection?<\/strong> Contact us at <strong><a href=\"mailto:info@szfilmfactory.com\" target=\"_blank\" rel=\"noreferrer noopener\">info@szfilmfactory.com<\/a><\/strong> or send your requirements through our contact form to discuss the right film and COF for your application.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">FAQ<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">What is a good COF for BOPP film?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>There is no universal \u201cgood\u201d COF for BOPP film.<\/strong> The suitable value depends on the application, machine, contact surface, and processing conditions.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Does lower COF always mean better BOPP film?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>No.<\/strong> A lower COF improves sliding, but excessive slip may not be suitable for applications that require better film grip or stacking stability.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What is the difference between COF and slip?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>COF is the measured friction value, while slip describes how easily a material moves over another surface.<\/strong> In BOPP film discussions, the two terms are closely related.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Can COF affect packaging machine performance?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Yes.<\/strong> COF can affect film feeding, film movement, machine speed, and packaging stability.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Does corona treatment change BOPP film COF?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Yes, corona treatment can influence surface properties and COF.<\/strong> The actual change depends on the film structure, treatment level, additives, and test conditions.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Can COF change over time?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Yes.<\/strong> BOPP film COF may change during storage because of additive migration, temperature, humidity, and surface changes.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Should I compare static or kinetic COF?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Both can be useful.<\/strong> Static COF is important for starting movement, while kinetic COF is useful for evaluating continuous sliding during processing.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">How can I choose the right BOPP film for my machine?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Start with the application and machine requirements, then compare COF and other technical properties.<\/strong> Technical testing reports and TDS data can make the selection more reliable.<\/p>","protected":false},"excerpt":{"rendered":"<p>Coefficient of friction (COF) is a key property of BOPP film that affects film movement, feeding, packing, and converting performance. Learn how COF is tested and how the right COF can improve your production process.<\/p>","protected":false},"author":1,"featured_media":3711,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[29],"tags":[31,36,67,35],"class_list":["post-3710","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-case-studies-tech-support","tag-bopp-film","tag-buying-guides","tag-cof","tag-tech-support"],"uagb_featured_image_src":{"full":["https:\/\/szfilmfactory.com\/wp-content\/uploads\/2026\/09\/What-Is-COF.jpg",800,533,false],"thumbnail":["https:\/\/szfilmfactory.com\/wp-content\/uploads\/2026\/09\/What-Is-COF-150x150.jpg",150,150,true],"medium":["https:\/\/szfilmfactory.com\/wp-content\/uploads\/2026\/09\/What-Is-COF-300x200.jpg",300,200,true],"medium_large":["https:\/\/szfilmfactory.com\/wp-content\/uploads\/2026\/09\/What-Is-COF-768x512.jpg",768,512,true],"large":["https:\/\/szfilmfactory.com\/wp-content\/uploads\/2026\/09\/What-Is-COF.jpg",800,533,false],"1536x1536":["https:\/\/szfilmfactory.com\/wp-content\/uploads\/2026\/09\/What-Is-COF.jpg",800,533,false],"2048x2048":["https:\/\/szfilmfactory.com\/wp-content\/uploads\/2026\/09\/What-Is-COF.jpg",800,533,false],"trp-custom-language-flag":["https:\/\/szfilmfactory.com\/wp-content\/uploads\/2026\/09\/What-Is-COF-18x12.jpg",18,12,true]},"uagb_author_info":{"display_name":"Ivy","author_link":"https:\/\/szfilmfactory.com\/ru\/blog\/author\/szfilmoutlook-com\/"},"uagb_comment_info":0,"uagb_excerpt":"Coefficient of friction (COF) is a key property of BOPP film that affects film movement, feeding, packing, and converting performance. Learn how COF is tested and how the right COF can improve your production process.","_links":{"self":[{"href":"https:\/\/szfilmfactory.com\/ru\/wp-json\/wp\/v2\/posts\/3710","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/szfilmfactory.com\/ru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/szfilmfactory.com\/ru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/szfilmfactory.com\/ru\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/szfilmfactory.com\/ru\/wp-json\/wp\/v2\/comments?post=3710"}],"version-history":[{"count":4,"href":"https:\/\/szfilmfactory.com\/ru\/wp-json\/wp\/v2\/posts\/3710\/revisions"}],"predecessor-version":[{"id":3852,"href":"https:\/\/szfilmfactory.com\/ru\/wp-json\/wp\/v2\/posts\/3710\/revisions\/3852"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/szfilmfactory.com\/ru\/wp-json\/wp\/v2\/media\/3711"}],"wp:attachment":[{"href":"https:\/\/szfilmfactory.com\/ru\/wp-json\/wp\/v2\/media?parent=3710"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/szfilmfactory.com\/ru\/wp-json\/wp\/v2\/categories?post=3710"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/szfilmfactory.com\/ru\/wp-json\/wp\/v2\/tags?post=3710"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}