{"id":2548,"date":"2026-07-21T15:54:28","date_gmt":"2026-07-21T15:54:28","guid":{"rendered":"https:\/\/www.fhysilicone.com\/?p=2548"},"modified":"2026-07-21T15:54:35","modified_gmt":"2026-07-21T15:54:35","slug":"self-bonding-lsr-to-pc-adhesion-methods-design-rules","status":"publish","type":"post","link":"https:\/\/www.fhysilicone.com\/fr\/self-bonding-lsr-to-pc-adhesion-methods-design-rules\/","title":{"rendered":"Collage autonome du LSR sur le PC : m\u00e9thodes d'adh\u00e9sion et r\u00e8gles de conception"},"content":{"rendered":"<p class=\"wp-block-paragraph\">Le caoutchouc de silicone liquide auto-adh\u00e9sif surmoul\u00e9 sur du polycarbonate permet d'associer, en une seule pi\u00e8ce int\u00e9gr\u00e9e, un composant structurel rigide \u00e0 une surface souple assurant l'\u00e9tanch\u00e9it\u00e9, l'amortissement, la pr\u00e9hension ou l'isolation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Cette combinaison de mat\u00e9riaux rigides et souples est largement utilis\u00e9e dans les dispositifs m\u00e9dicaux, les produits respiratoires, l'\u00e9lectronique, les appareils portables, les bo\u00eetiers \u00e9tanches, les composants optiques, les capteurs automobiles, les connecteurs et les ensembles de gestion des fluides. Le polycarbonate assure la structure de support rigide, tandis que le caoutchouc LSR apporte \u00e9lasticit\u00e9, \u00e9tanch\u00e9it\u00e9 et une interface souple.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Toutefois, il ne faut jamais partir du principe que l'adh\u00e9rence entre le LSR et le PC sera bonne.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Le terme \u201c auto-adh\u00e9sif \u201d ne signifie pas que tous les LSR auto-adh\u00e9sifs adh\u00e8rent \u00e0 toutes les qualit\u00e9s de polycarbonate dans toutes les conditions de moulage. L'adh\u00e9rence d\u00e9pend de la formulation exacte du LSR, de la nuance de r\u00e9sine PC, des additifs, de l'\u00e9tat de la surface, de la temp\u00e9rature du moule, du temps de durcissement, de la temp\u00e9rature de l'insert, de la g\u00e9om\u00e9trie du joint, du contr\u00f4le de la contamination et de l'environnement post-moulage.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Les fournisseurs de mat\u00e9riaux recommandent express\u00e9ment de tester chaque combinaison de LSR et de substrat avant la production en s\u00e9rie, car les diff\u00e9rentes qualit\u00e9s de plastique peuvent pr\u00e9senter des propri\u00e9t\u00e9s de surface diff\u00e9rentes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ce guide pr\u00e9sente les principales m\u00e9thodes d'adh\u00e9sion, les crit\u00e8res de s\u00e9lection des mat\u00e9riaux, les principes de conception des moules, les contr\u00f4les de processus, les proc\u00e9dures d'essai et les modes de d\u00e9faillance courants li\u00e9s au surmoulage par auto-adh\u00e9rence du caoutchouc LSR sur du PC.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/Self-Bonding-LSR-to-PCAdhesion-Methods-Design-Rules-1024x768.png\" alt=\"\" class=\"wp-image-2549\" srcset=\"https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/Self-Bonding-LSR-to-PCAdhesion-Methods-Design-Rules-1024x768.png 1024w, https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/Self-Bonding-LSR-to-PCAdhesion-Methods-Design-Rules-300x225.png 300w, https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/Self-Bonding-LSR-to-PCAdhesion-Methods-Design-Rules-768x576.png 768w, https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/Self-Bonding-LSR-to-PCAdhesion-Methods-Design-Rules-16x12.png 16w, https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/Self-Bonding-LSR-to-PCAdhesion-Methods-Design-Rules-600x450.png 600w, https:\/\/www.fhysilicone.com\/wp-content\/uploads\/2026\/07\/Self-Bonding-LSR-to-PCAdhesion-Methods-Design-Rules.png 1448w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Qu'est-ce que le LSR auto-adh\u00e9sif ?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Le LSR auto-adh\u00e9sif est un caoutchouc de silicone liquide sp\u00e9cialement formul\u00e9 pour d\u00e9velopper une adh\u00e9rence \u00e0 certains thermoplastiques ou m\u00e9taux au cours du processus de moulage et de durcissement.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Le LSR standard n'assure g\u00e9n\u00e9ralement pas une adh\u00e9rence chimique fiable sur du polycarbonate non trait\u00e9. Un assemblage classique peut donc n\u00e9cessiter :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Verrouillage m\u00e9canique<\/li>\n\n\n\n<li>Un guide d'introduction distinct<\/li>\n\n\n\n<li>Traitement au plasma<\/li>\n\n\n\n<li>Un adh\u00e9sif<\/li>\n\n\n\n<li>Assemblage secondaire<\/li>\n\n\n\n<li>Composants d'\u00e9tanch\u00e9it\u00e9 suppl\u00e9mentaires<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Le LSR auto-adh\u00e9sif ou sans appr\u00eat permet d'\u00e9liminer certaines de ces op\u00e9rations en adh\u00e9rant directement \u00e0 un substrat compatible lors du surmoulage.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Momentive d\u00e9finit le LSR auto-adh\u00e9sif comme un mat\u00e9riau con\u00e7u pour adh\u00e9rer directement \u00e0 des substrats sp\u00e9cifiques lors du moulage, sans n\u00e9cessiter d'appr\u00eat ni d'\u00e9tape de collage secondaire.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Le terme \u201c sp\u00e9cifique \u201d est important. L'acheteur doit s'assurer que la nuance de LSR choisie a \u00e9t\u00e9 con\u00e7ue et test\u00e9e pour la r\u00e9sine PC exacte utilis\u00e9e dans le produit final.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Pourquoi associer le LSR au polycarbonate ?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Le polycarbonate est couramment utilis\u00e9 pour la fabrication de composants rigides destin\u00e9s aux secteurs m\u00e9dical, \u00e9lectronique, industriel et optique. Selon sa composition, il peut offrir :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Haute r\u00e9sistance aux chocs<\/li>\n\n\n\n<li>Stabilit\u00e9 dimensionnelle<\/li>\n\n\n\n<li>Moulabilit\u00e9<\/li>\n\n\n\n<li>Transparence<\/li>\n\n\n\n<li>Rigidit\u00e9 structurelle<\/li>\n\n\n\n<li>Disponibilit\u00e9 dans les cat\u00e9gories destin\u00e9es au secteur de la sant\u00e9<\/li>\n\n\n\n<li>Disponibilit\u00e9 dans des nuances compatibles avec la st\u00e9rilisation<\/li>\n\n\n\n<li>Int\u00e9gration de clips, de nervures, de bossages, de rainures et d'\u00e9l\u00e9ments optiques<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Les grades de polycarbonate destin\u00e9s au secteur de la sant\u00e9 sont disponibles avec des \u00e9valuations de biocompatibilit\u00e9 et des programmes de gestion contr\u00f4l\u00e9e des changements ; toutefois, il convient de v\u00e9rifier aupr\u00e8s du fournisseur de r\u00e9sine le grade exact et la disponibilit\u00e9 dans chaque r\u00e9gion.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">LSR peut ajouter :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u00c9tanch\u00e9it\u00e9<\/li>\n\n\n\n<li>Vannes flexibles<\/li>\n\n\n\n<li>Surfaces douces au toucher<\/li>\n\n\n\n<li>Isolation antivibratoire<\/li>\n\n\n\n<li>Isolation \u00e9lectrique<\/li>\n\n\n\n<li>Amortissement<\/li>\n\n\n\n<li>Membranes souples<\/li>\n\n\n\n<li>Interfaces en contact avec la peau<\/li>\n\n\n\n<li>Joints int\u00e9gr\u00e9s<\/li>\n\n\n\n<li>Protection contre la poussi\u00e8re<\/li>\n\n\n\n<li>Fonctionnalit\u00e9s sensibles \u00e0 la pression<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Le surmoulage de ces deux mat\u00e9riaux permet de r\u00e9duire le nombre de composants et d'\u00e9viter l'installation d'un joint s\u00e9par\u00e9.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Applications courantes de la conversion de LSR vers PC<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Parmi les applications typiques des syst\u00e8mes \u00e0 deux composants, on peut citer :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Armatures et joints d'\u00e9tanch\u00e9it\u00e9 pour masques respiratoires<\/li>\n\n\n\n<li>Bo\u00eetiers pour dispositifs m\u00e9dicaux<\/li>\n\n\n\n<li>Joints pour \u00e9quipements de diagnostic<\/li>\n\n\n\n<li>Composants destin\u00e9s \u00e0 l'administration de m\u00e9dicaments<\/li>\n\n\n\n<li>Vannes de r\u00e9gulation des fluides<\/li>\n\n\n\n<li>Bo\u00eetiers pour appareils portables<\/li>\n\n\n\n<li>Boutons \u00e9lectroniques et membranes<\/li>\n\n\n\n<li>Bo\u00eetiers de connecteurs \u00e9tanches<\/li>\n\n\n\n<li>Bo\u00eetiers de capteurs<\/li>\n\n\n\n<li>Composants d'\u00e9clairage<\/li>\n\n\n\n<li>Bo\u00eetiers pour batteries et composants \u00e9lectroniques<\/li>\n\n\n\n<li>Ensembles optiques<\/li>\n\n\n\n<li>Joints d'\u00e9tanch\u00e9it\u00e9 pour radars et cam\u00e9ras automobiles<\/li>\n\n\n\n<li>Poign\u00e9es pour appareils portables<\/li>\n\n\n\n<li>Produits de sant\u00e9 r\u00e9utilisables<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Le surmoulage de polycarbonate avec du caoutchouc LSR est utilis\u00e9 dans les produits m\u00e9dicaux tels que les masques respiratoires et d'autres dispositifs n\u00e9cessitant des \u00e9l\u00e9ments d'\u00e9tanch\u00e9it\u00e9 moul\u00e9s.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Principales m\u00e9thodes d'adh\u00e9sion<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Il existe quatre strat\u00e9gies principales pour relier le LSR au PC :<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>LSR auto-adh\u00e9sif sans appr\u00eat<\/li>\n\n\n\n<li>Collage assist\u00e9 par appr\u00eat<\/li>\n\n\n\n<li>Activation ou traitement de surface<\/li>\n\n\n\n<li>Verrouillage m\u00e9canique<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Une conception robuste peut recourir \u00e0 plusieurs m\u00e9thodes.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">M\u00e9thode 1 : LSR \u00e0 adh\u00e9rence spontan\u00e9e sans appr\u00eat<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Le moulage LSR sans appr\u00eat et \u00e0 adh\u00e9rence spontan\u00e9e est souvent la m\u00e9thode privil\u00e9gi\u00e9e pour le moulage \u00e0 deux composants \u00e0 grand volume.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">L'insert en polycarbonate ou la pi\u00e8ce de premi\u00e8re injection est positionn\u00e9(e) dans le moule en LSR, puis le silicone auto-adh\u00e9sif est inject\u00e9 directement sur la surface d'assemblage expos\u00e9e. Au cours du durcissement, le LSR d\u00e9veloppe une adh\u00e9rence au polycarbonate compatible.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Parmi les avantages potentiels, on peut citer :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Moins d'\u00e9tapes de fabrication<\/li>\n\n\n\n<li>Pas d'application manuelle d'appr\u00eat<\/li>\n\n\n\n<li>Risque de contamination r\u00e9duit<\/li>\n\n\n\n<li>R\u00e9duction de l'utilisation de solvants<\/li>\n\n\n\n<li>Am\u00e9lioration de l'automatisation<\/li>\n\n\n\n<li>Un flux de production plus court<\/li>\n\n\n\n<li>R\u00e9duction de la main-d'\u0153uvre li\u00e9e \u00e0 l'assemblage<\/li>\n\n\n\n<li>Une r\u00e9partition plus homog\u00e8ne de la colle<\/li>\n\n\n\n<li>Meilleure adaptation au moulage en deux \u00e9tapes<\/li>\n\n\n\n<li>R\u00e9duction des stocks de produits en cours de fabrication<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">WACKER indique que certaines qualit\u00e9s de LSR auto-adh\u00e9sives peuvent adh\u00e9rer au PC sans traitement pr\u00e9alable du substrat et permettent une production automatis\u00e9e \u00e0 plusieurs composants.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Momentive propose \u00e9galement des gammes de LSR auto-adh\u00e9sifs, con\u00e7ues pour une adh\u00e9rence sans appr\u00eat sur le PC et d'autres thermoplastiques s\u00e9lectionn\u00e9s.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Limites de la liaison sans appr\u00eat<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Le collage sans appr\u00eat peut \u00e9chouer dans les cas suivants :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>La version PC n'est pas compatible<\/li>\n\n\n\n<li>La r\u00e9sine contient des additifs inadapt\u00e9s<\/li>\n\n\n\n<li>La surface est contamin\u00e9e<\/li>\n\n\n\n<li>L'insert est trop froid<\/li>\n\n\n\n<li>Le temps de durcissement est insuffisant<\/li>\n\n\n\n<li>La pression au niveau de l'interface est insuffisante<\/li>\n\n\n\n<li>Le LSR est moul\u00e9 sur l'envers d'un film ou d'un composant enduit<\/li>\n\n\n\n<li>L'ordinateur a vieilli ou a \u00e9t\u00e9 contamin\u00e9 pendant son stockage<\/li>\n\n\n\n<li>L'interface est soumise \u00e0 une contrainte de pelage<\/li>\n\n\n\n<li>La surface du moule est contamin\u00e9e<\/li>\n\n\n\n<li>La combinaison de mat\u00e9riaux n'a pas \u00e9t\u00e9 valid\u00e9e<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Le fait qu'un essai se soit av\u00e9r\u00e9 concluant avec une nuance de PC ne prouve pas la compatibilit\u00e9 avec une autre nuance issue de la m\u00eame famille de r\u00e9sines.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">M\u00e9thode 2 : Collage assist\u00e9 par appr\u00eat<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Il est possible d'appliquer un appr\u00eat sur la surface de collage en PC avant le moulage au LSR.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">L'appr\u00eat sert de couche favorisant l'adh\u00e9rence entre le silicone et le substrat thermoplastique.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">On peut envisager l'utilisation d'un appr\u00eat dans les cas suivants :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Le LSR s\u00e9lectionn\u00e9 n'est pas auto-adh\u00e9sif.<\/li>\n\n\n\n<li>L'adh\u00e9rence sans appr\u00eat n'est pas constante<\/li>\n\n\n\n<li>La surface du PC est difficile \u00e0 coller<\/li>\n\n\n\n<li>Cette application n\u00e9cessite une marge d'adh\u00e9rence suppl\u00e9mentaire<\/li>\n\n\n\n<li>Le projet utilise une qualit\u00e9 LSR existante<\/li>\n\n\n\n<li>Le volume de production ne justifie pas la mise en place d'un nouveau syst\u00e8me de gestion des mat\u00e9riaux<\/li>\n\n\n\n<li>Le verrouillage m\u00e9canique est limit\u00e9<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Il existe dans le commerce des appr\u00eats \u00e0 base de silicone destin\u00e9s \u00e0 am\u00e9liorer l'adh\u00e9rence sur les plastiques et d'autres substrats, mais il convient de v\u00e9rifier leur compatibilit\u00e9 avec le syst\u00e8me PC et LSR choisi.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Risques li\u00e9s au processus d'appr\u00eat<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">L'application de l'appr\u00eat introduit des contr\u00f4les suppl\u00e9mentaires :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Nettoyage des surfaces<\/li>\n\n\n\n<li>\u00c9paisseur de l'enduit<\/li>\n\n\n\n<li>Uniformit\u00e9 de la couverture<\/li>\n\n\n\n<li>Temps de s\u00e9chage<\/li>\n\n\n\n<li>Dur\u00e9e de conservation de l'appr\u00eat<\/li>\n\n\n\n<li>Manipulation des solvants<\/li>\n\n\n\n<li>Formation des op\u00e9rateurs<\/li>\n\n\n\n<li>Contr\u00f4les environnementaux<\/li>\n\n\n\n<li>Masquage des zones non \u00e0 souder<\/li>\n\n\n\n<li>Tra\u00e7abilit\u00e9 des lots<\/li>\n\n\n\n<li>\u00c9valuation r\u00e9glementaire<\/li>\n\n\n\n<li>\u00c9ventuelles imperfections esth\u00e9tiques<\/li>\n\n\n\n<li>Augmentation des co\u00fbts de cycle et de main-d'\u0153uvre<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Une quantit\u00e9 excessive d'appr\u00eat peut entra\u00eener la formation de d\u00e9p\u00f4ts, de marques visibles, l'affaiblissement des couches limites ou des variations dimensionnelles.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Une quantit\u00e9 insuffisante d'appr\u00eat peut laisser des zones non adh\u00e9rentes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Pour les produits \u00e0 usage m\u00e9dical ou destin\u00e9s \u00e0 entrer en contact avec des denr\u00e9es alimentaires, chaque appr\u00eat et chaque solvant doit \u00eatre pris en compte dans l'\u00e9valuation des mat\u00e9riaux et la conformit\u00e9 r\u00e9glementaire.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">M\u00e9thode 3 : Activation de surface<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Le traitement de surface peut augmenter l'\u00e9nergie de surface et am\u00e9liorer l'adh\u00e9rence dans certains syst\u00e8mes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Parmi les m\u00e9thodes envisageables, on peut citer :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Plasma atmosph\u00e9rique<\/li>\n\n\n\n<li>Plasma \u00e0 basse pression<\/li>\n\n\n\n<li>Traitement contre le coronavirus<\/li>\n\n\n\n<li>Traitement \u00e0 la flamme<\/li>\n\n\n\n<li>Traitement par UV et ozone<\/li>\n\n\n\n<li>Traitement chimique de surface<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Le traitement au plasma est utilis\u00e9 dans certains syst\u00e8mes de collage au silicone afin d'am\u00e9liorer l'adh\u00e9rence lorsque celle-ci s'av\u00e8re insuffisante sur un substrat non trait\u00e9.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Cependant, l'activation de la surface est sensible au temps. La surface trait\u00e9e peut perdre progressivement son \u00e9tat activ\u00e9 avant le surmoulage.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Un processus valid\u00e9 doit d\u00e9finir :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>M\u00e9thode de traitement<\/li>\n\n\n\n<li>Puissance<\/li>\n\n\n\n<li>Gaz<\/li>\n\n\n\n<li>Distance<\/li>\n\n\n\n<li>Vitesse de traitement<\/li>\n\n\n\n<li>Nombre de passages<\/li>\n\n\n\n<li>D\u00e9lai maximal avant le moulage<\/li>\n\n\n\n<li>Conditions de stockage<\/li>\n\n\n\n<li>Exigences en mati\u00e8re de propret\u00e9 des surfaces<\/li>\n\n\n\n<li>M\u00e9thode d'inspection ou de surveillance<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Aucun traitement de surface ne doit \u00eatre mis en \u0153uvre sans un plan de validation contr\u00f4l\u00e9.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">M\u00e9thode n\u00b0 4 : Verrouillage m\u00e9canique<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Le verrouillage m\u00e9canique utilise la forme du composant en PC pour maintenir physiquement le silicone durci en place.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Parmi les caract\u00e9ristiques communes, on peut citer :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Trous traversants<\/li>\n\n\n\n<li>Machines \u00e0 sous<\/li>\n\n\n\n<li>Contre-d\u00e9pouilles<\/li>\n\n\n\n<li>Rainures<\/li>\n\n\n\n<li>Windows<\/li>\n\n\n\n<li>Perforations<\/li>\n\n\n\n<li>Nervures de retenue<\/li>\n\n\n\n<li>Fonctionnalit\u00e9s de Dovetail<\/li>\n\n\n\n<li>Bords enveloppants<\/li>\n\n\n\n<li>Brides fix\u00e9es par embo\u00eetement<\/li>\n\n\n\n<li>Poches d'ancrage \u00e9largies<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Le LSR s'\u00e9coule \u00e0 travers ou autour de ces \u00e9l\u00e9ments et se fixe m\u00e9caniquement apr\u00e8s durcissement.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Un verrouillage m\u00e9canique est utile dans les cas suivants :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>L'adh\u00e9rence chimique est incertaine<\/li>\n\n\n\n<li>L'application subit une contrainte de pelage<\/li>\n\n\n\n<li>Ce lien est essentiel \u00e0 la s\u00e9curit\u00e9<\/li>\n\n\n\n<li>Le produit est soumis \u00e0 des flexions r\u00e9p\u00e9t\u00e9es<\/li>\n\n\n\n<li>L'interface entre en contact avec de l'eau ou des produits chimiques<\/li>\n\n\n\n<li>Un vieillissement prolong\u00e9 peut r\u00e9duire l'adh\u00e9rence<\/li>\n\n\n\n<li>La conception n\u00e9cessite un syst\u00e8me de retenue redondant.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Le verrouillage m\u00e9canique peut renforcer la liaison chimique, mais il ne doit pas servir \u00e0 compenser un processus de moulage non ma\u00eetris\u00e9.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Le choix des mat\u00e9riaux est la premi\u00e8re d\u00e9cision \u00e0 prendre en mati\u00e8re de conception<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Les nuances LSR et PC doivent \u00eatre choisies en tant que paire de mat\u00e9riaux ayant fait l'objet d'essais.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ne choisissez pas le PC en vous basant uniquement sur ses propri\u00e9t\u00e9s m\u00e9caniques, et choisissez le LSR s\u00e9par\u00e9ment, \u00e0 un stade ult\u00e9rieur.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">L'\u00e9valuation devrait porter sur :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>D\u00e9nomination commerciale et qualit\u00e9 exactes du LSR<\/li>\n\n\n\n<li>D\u00e9nomination commerciale et cat\u00e9gorie exactes du PC<\/li>\n\n\n\n<li>Couleur de l'ordinateur<\/li>\n\n\n\n<li>Couleur LSR<\/li>\n\n\n\n<li>Additifs pour PC<\/li>\n\n\n\n<li>Syst\u00e8me ignifuge<\/li>\n\n\n\n<li>Stabilisateurs UV<\/li>\n\n\n\n<li>Additifs internes de d\u00e9moulage<\/li>\n\n\n\n<li>Renfort en verre<\/li>\n\n\n\n<li>Statut \u00ab \u00e0 usage m\u00e9dical \u00bb ou \u00ab en contact avec les aliments \u00bb<\/li>\n\n\n\n<li>Exigences en mati\u00e8re de st\u00e9rilisation<\/li>\n\n\n\n<li>Exigences en mati\u00e8re de transparence<\/li>\n\n\n\n<li>Compatibilit\u00e9 avec les temp\u00e9ratures de transformation<\/li>\n\n\n\n<li>Exigences en mati\u00e8re de contr\u00f4le des modifications<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">WACKER pr\u00e9cise que, m\u00eame lorsqu'une s\u00e9rie de LSR est con\u00e7ue pour adh\u00e9rer au PC et \u00e0 d'autres plastiques haute performance, chaque substrat doit faire l'objet d'essais avant la production en s\u00e9rie, car les propri\u00e9t\u00e9s de surface varient.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Ne consid\u00e9rez pas toutes les cat\u00e9gories de PC comme \u00e9quivalentes<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Deux types de polycarbonate peuvent pr\u00e9senter des diff\u00e9rences au niveau :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Poids mol\u00e9culaire<\/li>\n\n\n\n<li>Indice de fluidit\u00e9 \u00e0 chaud<\/li>\n\n\n\n<li>R\u00e9sistance \u00e0 la chaleur<\/li>\n\n\n\n<li>Emballage antiadh\u00e9sif<\/li>\n\n\n\n<li>Colorants<\/li>\n\n\n\n<li>Retardateurs de flamme<\/li>\n\n\n\n<li>Renfort<\/li>\n\n\n\n<li>Additifs anti-UV<\/li>\n\n\n\n<li>Modificateurs d'impact<\/li>\n\n\n\n<li>Dossiers m\u00e9dicaux<\/li>\n\n\n\n<li>Compatibilit\u00e9 avec la st\u00e9rilisation<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Ces diff\u00e9rences peuvent avoir une incidence sur le comportement au moulage et l'adh\u00e9rence \u00e0 l'interface.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Une nuance de PC naturel et une nuance de PC noir ignifug\u00e9 doivent \u00eatre consid\u00e9r\u00e9es comme deux substrats distincts lors des essais de qualification d'adh\u00e9rence.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tout changement de fournisseur de r\u00e9sine, de type de r\u00e9sine, de pigment, de teneur en mat\u00e9riaux recycl\u00e9s ou d'ensemble d'additifs doit donner lieu \u00e0 une r\u00e9vision technique.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Compatibilit\u00e9 thermique<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Le LSR n\u00e9cessite de la chaleur pour durcir, tandis que le PC peut se ramollir, se d\u00e9former, se d\u00e9colorer ou accumuler des contraintes internes s'il est expos\u00e9 \u00e0 des conditions de moulage inadapt\u00e9es.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">L'ordinateur s\u00e9lectionn\u00e9 doit r\u00e9sister \u00e0 :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Temp\u00e9rature du moule en LSR<\/li>\n\n\n\n<li>Pr\u00e9chauffage de l'insert<\/li>\n\n\n\n<li>Pression d'injection<\/li>\n\n\n\n<li>Temps de durcissement<\/li>\n\n\n\n<li>Cycles de moulage r\u00e9p\u00e9t\u00e9s<\/li>\n\n\n\n<li>Chauffage localis\u00e9 \u00e0 l'interface<\/li>\n\n\n\n<li>Post-durcissement, si n\u00e9cessaire<\/li>\n\n\n\n<li>St\u00e9rilisation<\/li>\n\n\n\n<li>Vieillissement thermique<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Lorsqu'un PC standard ne supporte pas les conditions de durcissement requises pour le LSR, on peut envisager d'utiliser un polycarbonate r\u00e9sistant \u00e0 des temp\u00e9ratures plus \u00e9lev\u00e9es ou un LSR durcissant \u00e0 basse temp\u00e9rature.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Des grades sp\u00e9ciaux de polycarbonate r\u00e9sistants aux temp\u00e9ratures \u00e9lev\u00e9es ont \u00e9t\u00e9 mis au point pour les applications de surmoulage LSR dans lesquelles la r\u00e9sistance thermique standard peut s'av\u00e9rer insuffisante.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dow propose \u00e9galement des solutions LSR \u00e0 durcissement \u00e0 basse temp\u00e9rature, destin\u00e9es aux substrats thermosensibles et aux sections surmoul\u00e9es \u00e9paisses.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">S\u00e9chage et manipulation de l'insert en PC<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Le PC est sensible \u00e0 l'humidit\u00e9 pendant son processus de moulage ; il est donc indispensable de respecter les recommandations du fournisseur de thermoplastiques en mati\u00e8re de s\u00e9chage et de mise en \u0153uvre lors de la fabrication de l'insert rigide.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Apr\u00e8s le moulage, l'insert doit \u00eatre prot\u00e9g\u00e9 contre :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>P\u00e9trole<\/li>\n\n\n\n<li>Poussi\u00e8re<\/li>\n\n\n\n<li>Empreintes digitales<\/li>\n\n\n\n<li>Sprays de d\u00e9moulage<\/li>\n\n\n\n<li>R\u00e9sidus de nettoyage<\/li>\n\n\n\n<li>Contamination de l'emballage<\/li>\n\n\n\n<li>Condensation<\/li>\n\n\n\n<li>Dur\u00e9e de stockage excessive<\/li>\n\n\n\n<li>Contact avec des gants incompatibles<\/li>\n\n\n\n<li>Huiles de silicone provenant d'activit\u00e9s non li\u00e9es<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">La zone de collage doit rester propre et s\u00e8che avant le surmoulage au LSR.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Le processus de nettoyage approuv\u00e9 doit d\u00e9finir :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Produit nettoyant<\/li>\n\n\n\n<li>Concentration<\/li>\n\n\n\n<li>Mode d'emploi<\/li>\n\n\n\n<li>M\u00e9thode de s\u00e9chage<\/li>\n\n\n\n<li>Dur\u00e9e maximale de conservation<\/li>\n\n\n\n<li>Emballage<\/li>\n\n\n\n<li>Gants de manutention<\/li>\n\n\n\n<li>Crit\u00e8res d'acceptation<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u00c9vitez d'utiliser un produit nettoyant agressif sans avoir v\u00e9rifi\u00e9 son effet sur la fissuration sous contrainte du PC et la chimie de surface.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Moulage en une seule \u00e9tape, moulage par insertion et moulage en deux \u00e9tapes<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Surmoulage d'inserts<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">La pi\u00e8ce en plastique est moul\u00e9e lors d'une op\u00e9ration distincte, puis contr\u00f4l\u00e9e, stock\u00e9e et enfin plac\u00e9e dans le moule en LSR.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Parmi les avantages, on peut citer :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Optimisation distincte de chaque processus de moulage<\/li>\n\n\n\n<li>Planification flexible de la production<\/li>\n\n\n\n<li>Baisse des investissements dans les \u00e9quipements \u00e0 plusieurs composants<\/li>\n\n\n\n<li>Un d\u00e9veloppement initial plus simple<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Parmi les inconv\u00e9nients, on peut citer :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Manutention suppl\u00e9mentaire<\/li>\n\n\n\n<li>Contamination de surface<\/li>\n\n\n\n<li>Insert de refroidissement<\/li>\n\n\n\n<li>Stock<\/li>\n\n\n\n<li>Chargement manuel<\/li>\n\n\n\n<li>Erreurs de positionnement<\/li>\n\n\n\n<li>Intervalle plus long entre les \u00e9tapes de moulage<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Moulage en deux \u00e9tapes<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">La pi\u00e8ce en PC est moul\u00e9e lors de la premi\u00e8re injection, puis transf\u00e9r\u00e9e directement dans une autre cavit\u00e9 pour le surmoulage LSR.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Parmi les avantages potentiels, on peut citer :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Surface en PC chaude, tout juste moul\u00e9e<\/li>\n\n\n\n<li>R\u00e9duction de la contamination<\/li>\n\n\n\n<li>Court d\u00e9lai entre les \u00e9tapes de moulage<\/li>\n\n\n\n<li>Am\u00e9lioration de l'automatisation<\/li>\n\n\n\n<li>Manipulation r\u00e9duite<\/li>\n\n\n\n<li>Higher production consistency<\/li>\n\n\n\n<li>R\u00e9duction des stocks de produits en cours de fabrication<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">WACKER describes self-adhesive LSR as suitable for large-series overmolded parts produced through multicomponent or shuttle-mold processes.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Rotary or Shuttle Mold<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">A rotary mold, index plate, or shuttle system transfers the PC component from the thermoplastic cavity to the LSR cavity.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The design must account for:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Different mold temperatures<\/li>\n\n\n\n<li>PC cooling and shrinkage<\/li>\n\n\n\n<li>LSR curing temperature<\/li>\n\n\n\n<li>Positionnement de l'insert<\/li>\n\n\n\n<li>Cavity alignment<\/li>\n\n\n\n<li>Cycle balancing<\/li>\n\n\n\n<li>Robot access<\/li>\n\n\n\n<li>Mold-surface isolation<\/li>\n\n\n\n<li>Differential thermal expansion<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Design the Interface for Shear, Not Peel<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Adhesive joints usually perform better when loads act in shear or compression rather than peeling the silicone away from the PC edge.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Avoid designs where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A thin silicone lip can be lifted easily<\/li>\n\n\n\n<li>The bond line terminates at a sharp exposed edge<\/li>\n\n\n\n<li>Repeated user contact pulls directly on the interface<\/li>\n\n\n\n<li>Assembly force peels the silicone backward<\/li>\n\n\n\n<li>Fluid pressure opens the bond line<\/li>\n\n\n\n<li>A cable pulls perpendicular to the interface<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Prefer designs where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The LSR wraps around the PC edge<\/li>\n\n\n\n<li>The interface has adequate overlap<\/li>\n\n\n\n<li>Loads are distributed over a wide area<\/li>\n\n\n\n<li>Mechanical anchors support the bond<\/li>\n\n\n\n<li>The bond edge is protected<\/li>\n\n\n\n<li>Sealing pressure pushes the LSR toward the PC<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Increase Bonding Area Carefully<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A larger bonding area can improve total retention, but more area does not automatically solve poor adhesion.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The interface should be:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Wide enough for stable bonding<\/li>\n\n\n\n<li>Accessible to LSR flow<\/li>\n\n\n\n<li>Properly vented<\/li>\n\n\n\n<li>Free of sharp changes in thickness<\/li>\n\n\n\n<li>Protected from trapped air<\/li>\n\n\n\n<li>Designed for uniform heating<\/li>\n\n\n\n<li>Easy to inspect<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Long narrow bonding paths can trap air or create incomplete filling.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Add Mechanical Anchors in Critical Areas<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Mechanical locking features should be considered near:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Languettes \u00e0 tirer<\/li>\n\n\n\n<li>Hinges<\/li>\n\n\n\n<li>User-contact edges<\/li>\n\n\n\n<li>Sorties de c\u00e2bles<\/li>\n\n\n\n<li>Valve regions<\/li>\n\n\n\n<li>Membranes minces<\/li>\n\n\n\n<li>Corners<\/li>\n\n\n\n<li>High-pressure sealing areas<\/li>\n\n\n\n<li>Areas exposed to repeated bending<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Through-holes allow the LSR on one side of the PC to connect with silicone on the opposite side, creating a strong physical lock.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The hole diameter and spacing must allow complete filling without weakening the plastic structure.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Avoid Sharp Corners<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Sharp PC corners can:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Restrict LSR flow<\/li>\n\n\n\n<li>Create air traps<\/li>\n\n\n\n<li>Concentrate stress<\/li>\n\n\n\n<li>Cut or tear the silicone<\/li>\n\n\n\n<li>Reduce effective bonding area<\/li>\n\n\n\n<li>Create thin sections<\/li>\n\n\n\n<li>Encourage crack initiation<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Use appropriate radii at the interface.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The radius must be large enough to improve flow and stress distribution while still meeting the functional geometry.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Control LSR Thickness<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Very thin LSR sections may:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Cure too quickly at the surface<\/li>\n\n\n\n<li>Fill incompletely<\/li>\n\n\n\n<li>Tear during demolding<\/li>\n\n\n\n<li>Provide insufficient peel-test width<\/li>\n\n\n\n<li>Create inconsistent bond strength<\/li>\n\n\n\n<li>Be damaged during use<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Very thick sections may:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Require longer curing<\/li>\n\n\n\n<li>Increase cycle time<\/li>\n\n\n\n<li>Create temperature gradients<\/li>\n\n\n\n<li>Increase shrinkage effects<\/li>\n\n\n\n<li>Distort the PC insert<\/li>\n\n\n\n<li>Trap air<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The thickness should be consistent where possible.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Gradual transitions are preferable to sudden changes.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Gate Location<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The LSR gate should be positioned to promote complete and uniform filling of the bonding interface.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A poor gate location can cause:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Air entrapment<\/li>\n\n\n\n<li>Flow hesitation<\/li>\n\n\n\n<li>Uneven interface pressure<\/li>\n\n\n\n<li>Premature curing<\/li>\n\n\n\n<li>Weak weld lines<\/li>\n\n\n\n<li>Incomplete encapsulation<\/li>\n\n\n\n<li>Excessive pressure on the PC insert<\/li>\n\n\n\n<li>Insert displacement<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The gate should not direct a high-velocity material stream against a fragile PC wall.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The gate vestige should also be positioned away from:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Sealing surfaces<\/li>\n\n\n\n<li>Cosmetic surfaces<\/li>\n\n\n\n<li>Membranes minces<\/li>\n\n\n\n<li>User-contact areas<\/li>\n\n\n\n<li>Critical bond edges<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Venting and Vacuum<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">LSR can flow into very small gaps, but trapped air can still prevent full contact with the PC surface.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Air traps may create:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Local unbonded spots<\/li>\n\n\n\n<li>Bulles<\/li>\n\n\n\n<li>Surface burns<\/li>\n\n\n\n<li>Short filling<\/li>\n\n\n\n<li>Weak bond initiation points<\/li>\n\n\n\n<li>Leak paths<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Vacuum-assisted molding and properly located vents can improve filling consistency.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Vents must be designed carefully because low-viscosity uncured LSR can create flash.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Protect the Nonbonding Areas<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Self-bonding LSR should bond to the PC component but release cleanly from the mold.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The mold may require:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Appropriate tool steel<\/li>\n\n\n\n<li>Rev\u00eatement de surface<\/li>\n\n\n\n<li>Controlled polish<\/li>\n\n\n\n<li>Defined texture<\/li>\n\n\n\n<li>Temperature balance<\/li>\n\n\n\n<li>Selective release treatment<\/li>\n\n\n\n<li>Protected shutoff areas<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">WACKER reports that its PC-bonding LSR technology is designed to adhere to the hard component without bonding to the mold, supporting automated production.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">However, actual release performance must be proven with the production tool.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Shutoff Design<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The boundary between exposed PC and overmolded LSR requires precise shutoff geometry.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Poor shutoffs may cause:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Silicone flash on the PC surface<\/li>\n\n\n\n<li>Cosmetic defects<\/li>\n\n\n\n<li>Leakage paths<\/li>\n\n\n\n<li>Difficult trimming<\/li>\n\n\n\n<li>Damage to optical areas<\/li>\n\n\n\n<li>Uncontrolled bond edges<\/li>\n\n\n\n<li>PC deformation<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The shutoff should:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Support the PC insert<\/li>\n\n\n\n<li>Prevent insert movement<\/li>\n\n\n\n<li>Avoid excessive clamping stress<\/li>\n\n\n\n<li>Limit flash<\/li>\n\n\n\n<li>Protect finished surfaces<\/li>\n\n\n\n<li>Account for PC dimensional tolerance<\/li>\n\n\n\n<li>Remain maintainable throughout tool life<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">PC Insert Temperature<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A warm PC insert can improve bonding in some systems because the interface reaches the required reaction temperature more quickly.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">An insert that is too cold may:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Delay adhesion development<\/li>\n\n\n\n<li>Increase cure-time requirements<\/li>\n\n\n\n<li>Create weak areas<\/li>\n\n\n\n<li>Cause condensation in humid environments<\/li>\n\n\n\n<li>Produce inconsistent bonding between cycles<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">An insert that is too hot may:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Deform<\/li>\n\n\n\n<li>Accumulate stress<\/li>\n\n\n\n<li>Lose dimensional accuracy<\/li>\n\n\n\n<li>Increase sticking<\/li>\n\n\n\n<li>Affect optical quality<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The validated process should define the acceptable insert-temperature range at the time of overmolding.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Mold Temperature and Cure Time<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Self-bonding LSR requires enough time and temperature to cure and develop adhesion.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Insufficient cure can lead to:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Adhesive failure<\/li>\n\n\n\n<li>Soft or tacky silicone<\/li>\n\n\n\n<li>Poor mechanical properties<\/li>\n\n\n\n<li>Unstable dimensions<\/li>\n\n\n\n<li>Weak peel strength<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Excessive heat exposure can:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Deform PC<\/li>\n\n\n\n<li>Increase cycle time<\/li>\n\n\n\n<li>Discolor the plastic<\/li>\n\n\n\n<li>Affect additives<\/li>\n\n\n\n<li>Increase internal stress<\/li>\n\n\n\n<li>Reduce production efficiency<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Use the material supplier\u2019s recommended processing window as the starting point and develop a validated production window through trials.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Pressure at the Interface<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The LSR must contact the PC surface continuously before curing.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Insufficient interface pressure may create:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Dry spots<\/li>\n\n\n\n<li>Air pockets<\/li>\n\n\n\n<li>Partial adhesion<\/li>\n\n\n\n<li>Weak edges<\/li>\n\n\n\n<li>Leak paths<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Excessive injection pressure may:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Move the insert<\/li>\n\n\n\n<li>Deform thin PC walls<\/li>\n\n\n\n<li>Open shutoffs<\/li>\n\n\n\n<li>Create flash<\/li>\n\n\n\n<li>Damage optical surfaces<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Balanced filling is usually more important than maximum injection pressure.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Cure Inhibition and Contamination<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Platinum-cured LSR can be affected by certain contaminants.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Potential sources include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Mat\u00e9riaux contenant du soufre<\/li>\n\n\n\n<li>Amines<\/li>\n\n\n\n<li>Phosphorus compounds<\/li>\n\n\n\n<li>Some adhesives<\/li>\n\n\n\n<li>Some pigments<\/li>\n\n\n\n<li>Rubber gloves<\/li>\n\n\n\n<li>Lubrifiants<\/li>\n\n\n\n<li>Cleaning products<\/li>\n\n\n\n<li>Residues from other elastomers<\/li>\n\n\n\n<li>Mat\u00e9riaux d'emballage<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">WACKER warns that amines, sulfur, and phosphorus compounds can interfere with platinum-catalyzed LSR systems.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The production area should control contact materials and cross-contamination.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Adhesion Failure Modes<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">D\u00e9faillance de l'adh\u00e9rence<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The silicone separates cleanly from the PC surface.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This usually indicates that the interface bond is weaker than the silicone itself.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Parmi les causes possibles, on peut citer :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Incompatible material pair<\/li>\n\n\n\n<li>Contamination de surface<\/li>\n\n\n\n<li>Insufficient temperature<\/li>\n\n\n\n<li>Short cure time<\/li>\n\n\n\n<li>Incorrect LSR mixing<\/li>\n\n\n\n<li>Aged or unsuitable PC surface<\/li>\n\n\n\n<li>Inadequate treatment<\/li>\n\n\n\n<li>Incorrect primer<\/li>\n\n\n\n<li>Poor primer application<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Rupture coh\u00e9sive<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The silicone tears while a layer remains attached to the PC.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This indicates that the interface bond is stronger than the local silicone strength.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Cohesive failure is often the preferred result during peel testing.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">WACKER reports cohesive failure in peel testing for selected PC and self-bonding LSR combinations, with the silicone tearing while the interface remained intact.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Mixed Failure<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Part of the interface separates cleanly while another area tears through the silicone.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Mixed failure may indicate:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Uneven surface condition<\/li>\n\n\n\n<li>Temperature variation<\/li>\n\n\n\n<li>Partial contamination<\/li>\n\n\n\n<li>Air entrapment<\/li>\n\n\n\n<li>Uneven primer<\/li>\n\n\n\n<li>Inconsistent interface pressure<\/li>\n\n\n\n<li>Variable cure<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">PC Substrate Failure<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The PC cracks or breaks before the silicone bond separates.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This may indicate strong adhesion, but it can also reveal:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Excessive stress concentration<\/li>\n\n\n\n<li>Weak PC geometry<\/li>\n\n\n\n<li>Internal molding stress<\/li>\n\n\n\n<li>Chemical attack<\/li>\n\n\n\n<li>Poor mechanical design<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Peel Testing<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A 90-degree or 180-degree peel test is commonly used to compare adhesion between material combinations and process conditions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A controlled test should define:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Specimen geometry<\/li>\n\n\n\n<li>Bonding width<\/li>\n\n\n\n<li>LSR thickness<\/li>\n\n\n\n<li>PC thickness<\/li>\n\n\n\n<li>Peel angle<\/li>\n\n\n\n<li>Pull speed<\/li>\n\n\n\n<li>Dur\u00e9e de conditionnement<\/li>\n\n\n\n<li>Temp\u00e9rature d'essai<\/li>\n\n\n\n<li>Quantit\u00e9 d'\u00e9chantillons<\/li>\n\n\n\n<li>Mode de d\u00e9faillance<\/li>\n\n\n\n<li>Minimum peel strength<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Report both the force and failure mode.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A high force followed by clean adhesive separation may indicate a different risk than a lower force with consistent cohesive tearing.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">WACKER reports peel-test results for selected self-adhesive LSR and PC combinations, but those supplier values should not be used as automatic acceptance criteria for a different product geometry or resin grade.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Tensile Pull Testing<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">For buttons, inserts, connectors, and circular seals, a tensile pull or push-out test may better represent the actual load.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The test fixture should reproduce the expected service direction.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Possible measurements include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Maximum pull force<\/li>\n\n\n\n<li>Force at first separation<\/li>\n\n\n\n<li>Displacement at failure<\/li>\n\n\n\n<li>Failure location<\/li>\n\n\n\n<li>Percentage of cohesive failure<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Leak Testing<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">When the LSR functions as a waterproof seal, bond testing alone is not enough.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The assembly may also require:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Air-pressure decay testing<\/li>\n\n\n\n<li>Vacuum decay testing<\/li>\n\n\n\n<li>Water spray testing<\/li>\n\n\n\n<li>Immersion testing<\/li>\n\n\n\n<li>Bubble testing<\/li>\n\n\n\n<li>Burst-pressure testing<\/li>\n\n\n\n<li>Fluid-pressure testing<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Leak testing should be repeated after environmental conditioning.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Environmental Validation<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The LSR-to-PC bond should be evaluated after relevant exposures, such as:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Cycles thermiques<\/li>\n\n\n\n<li>High-temperature aging<\/li>\n\n\n\n<li>Low-temperature exposure<\/li>\n\n\n\n<li>Forte humidit\u00e9<\/li>\n\n\n\n<li>Water immersion<\/li>\n\n\n\n<li>Produits d\u00e9tergents<\/li>\n\n\n\n<li>D\u00e9sinfectants<\/li>\n\n\n\n<li>Skin oils<\/li>\n\n\n\n<li>Automotive fluids<\/li>\n\n\n\n<li>Exposition aux UV<\/li>\n\n\n\n<li>Vibration<\/li>\n\n\n\n<li>Mechanical shock<\/li>\n\n\n\n<li>Repeated flexing<\/li>\n\n\n\n<li>St\u00e9rilisation<\/li>\n\n\n\n<li>Vieillissement acc\u00e9l\u00e9r\u00e9<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">A bond that performs well immediately after molding may weaken after aging or chemical exposure.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Sterilization Considerations<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">For healthcare products, evaluate the complete PC-LSR assembly after the intended sterilization process.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Possible methods include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Oxyde d'\u00e9thyl\u00e8ne<\/li>\n\n\n\n<li>Steam<\/li>\n\n\n\n<li>Rayonnement gamma<\/li>\n\n\n\n<li>Faisceau d'\u00e9lectrons<\/li>\n\n\n\n<li>Radiographie<\/li>\n\n\n\n<li>Peroxyde d'hydrog\u00e8ne vaporis\u00e9<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The sterilization process can affect:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>PC transparency<\/li>\n\n\n\n<li>PC stress cracking<\/li>\n\n\n\n<li>Duret\u00e9 du silicone<\/li>\n\n\n\n<li>Silicone elongation<\/li>\n\n\n\n<li>R\u00e9sistance d'adh\u00e9rence<\/li>\n\n\n\n<li>Couleur<\/li>\n\n\n\n<li>Dimensions<\/li>\n\n\n\n<li>Force d'\u00e9tanch\u00e9it\u00e9<\/li>\n\n\n\n<li>Substances extractibles<\/li>\n\n\n\n<li>Vieillissement \u00e0 long terme<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Certain self-bonding LSR and PC systems have demonstrated compatibility with repeated steam sterilization, but this performance is material-grade-specific and does not apply automatically to all combinations.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Quality-Control Plan<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A production control plan may include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>PC resin verification<\/li>\n\n\n\n<li>LSR batch verification<\/li>\n\n\n\n<li>Pigment verification<\/li>\n\n\n\n<li>Insert dimensions<\/li>\n\n\n\n<li>Insert cleanliness<\/li>\n\n\n\n<li>Insert temperature<\/li>\n\n\n\n<li>Temp\u00e9rature du moule<\/li>\n\n\n\n<li>Pression d'injection<\/li>\n\n\n\n<li>Temps de durcissement<\/li>\n\n\n\n<li>Inspection visuelle<\/li>\n\n\n\n<li>Inspection rapide<\/li>\n\n\n\n<li>Bond-edge inspection<\/li>\n\n\n\n<li>Peel or pull testing<\/li>\n\n\n\n<li>Contr\u00f4le d'\u00e9tanch\u00e9it\u00e9<\/li>\n\n\n\n<li>Tests fonctionnels<\/li>\n\n\n\n<li>Tra\u00e7abilit\u00e9 des lots<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">For medical, automotive, or safety-critical products, define the testing frequency and acceptance criteria before mass production.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Change Control<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Adhesion is sensitive to material and process changes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Require notification before changing:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>PC grade<\/li>\n\n\n\n<li>PC supplier<\/li>\n\n\n\n<li>PC manufacturing site<\/li>\n\n\n\n<li>Couleur de l'ordinateur<\/li>\n\n\n\n<li>Additive package<\/li>\n\n\n\n<li>Emballage antiadh\u00e9sif<\/li>\n\n\n\n<li>Recycled content<\/li>\n\n\n\n<li>LSR grade<\/li>\n\n\n\n<li>LSR supplier<\/li>\n\n\n\n<li>LSR pigment<\/li>\n\n\n\n<li>Introduction<\/li>\n\n\n\n<li>Produit nettoyant<\/li>\n\n\n\n<li>Traitement de surface<\/li>\n\n\n\n<li>Mold coating<\/li>\n\n\n\n<li>Temp\u00e9rature du moule<\/li>\n\n\n\n<li>Conditions de gu\u00e9rison<\/li>\n\n\n\n<li>Production site<\/li>\n\n\n\n<li>M\u00e9thode de st\u00e9rilisation<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">SABIC notes that its healthcare polycarbonate portfolio uses formula-lock and management-of-change controls, illustrating why controlled resin sourcing matters in regulated applications.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Recommended Development Process<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Phase 1: Define the Application<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Document:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Fonctionnalit\u00e9s du produit<\/li>\n\n\n\n<li>Bonding purpose<\/li>\n\n\n\n<li>Sealing requirement<\/li>\n\n\n\n<li>Expected load<\/li>\n\n\n\n<li>Temp\u00e9rature<\/li>\n\n\n\n<li>Exposition \u00e0 des substances chimiques<\/li>\n\n\n\n<li>St\u00e9rilisation<\/li>\n\n\n\n<li>Service life<\/li>\n\n\n\n<li>Regulatory market<\/li>\n\n\n\n<li>Volume annuel<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Phase 2: Screen Material Pairs<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Select several candidate combinations of:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Self-bonding LSR grade<\/li>\n\n\n\n<li>PC grade<\/li>\n\n\n\n<li>Couleur<\/li>\n\n\n\n<li>Duret\u00e9<\/li>\n\n\n\n<li>R\u00e9sistance \u00e0 la chaleur<\/li>\n\n\n\n<li>Regulatory status<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Request supplier adhesion tables or technical support where available.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Phase 3: Produce Test Plaques<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Mold standardized plaques using representative:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>PC processing conditions<\/li>\n\n\n\n<li>LSR processing conditions<\/li>\n\n\n\n<li>Surface conditions<\/li>\n\n\n\n<li>Interface thickness<\/li>\n\n\n\n<li>Temps de durcissement<\/li>\n\n\n\n<li>Insert temperature<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Compare peel strength and failure mode.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Phase 4: Prototype the Real Geometry<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Test actual components because plaque results may not represent:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Corner flow<\/li>\n\n\n\n<li>Thin sections<\/li>\n\n\n\n<li>Gate location<\/li>\n\n\n\n<li>Mouvement d'insertion<\/li>\n\n\n\n<li>Bond-edge geometry<\/li>\n\n\n\n<li>Mechanical stresses<\/li>\n\n\n\n<li>Pression d'\u00e9tanch\u00e9it\u00e9<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Phase 5: Establish the Process Window<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Test combinations of:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Low and high mold temperature<\/li>\n\n\n\n<li>Short and long cure time<\/li>\n\n\n\n<li>Low and high insert temperature<\/li>\n\n\n\n<li>Minimum and maximum holding time<\/li>\n\n\n\n<li>Material-lot variation<\/li>\n\n\n\n<li>PC color variation<\/li>\n\n\n\n<li>LSR pigment variation<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Phase 6: Complete Environmental Testing<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Evaluate bonded samples after the required aging, fluid, thermal, mechanical, and sterilization conditions.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Phase 7: Validate Production<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Valider :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Material handling<\/li>\n\n\n\n<li>PC molding<\/li>\n\n\n\n<li>Insert storage<\/li>\n\n\n\n<li>Nettoyage des surfaces<\/li>\n\n\n\n<li>Insert transfer<\/li>\n\n\n\n<li>LSR metering and mixing<\/li>\n\n\n\n<li>Param\u00e8tres de moulage<\/li>\n\n\n\n<li>D\u00e9moulage<\/li>\n\n\n\n<li>Inspection<\/li>\n\n\n\n<li>Emballage<\/li>\n\n\n\n<li>Tra\u00e7abilit\u00e9<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Informations \u00e0 inclure dans un appel d'offres<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Provide the molding supplier with:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>PC trade name and exact grade<\/li>\n\n\n\n<li>LSR trade name and exact grade, when selected<\/li>\n\n\n\n<li>Dessin en deux dimensions<\/li>\n\n\n\n<li>Mod\u00e8le en trois dimensions<\/li>\n\n\n\n<li>Bonding-area dimensions<\/li>\n\n\n\n<li>Required LSR hardness<\/li>\n\n\n\n<li>PC and LSR colors<\/li>\n\n\n\n<li>Mechanical load direction<\/li>\n\n\n\n<li>Required peel or pull strength<\/li>\n\n\n\n<li>Waterproof or leak requirement<\/li>\n\n\n\n<li>Temp\u00e9rature de fonctionnement<\/li>\n\n\n\n<li>Exposition \u00e0 des substances chimiques<\/li>\n\n\n\n<li>M\u00e9thode de st\u00e9rilisation<\/li>\n\n\n\n<li>Exigences r\u00e9glementaires<\/li>\n\n\n\n<li>Quantit\u00e9 annuelle<\/li>\n\n\n\n<li>Quantit\u00e9 de prototypes<\/li>\n\n\n\n<li>Cosmetic requirements<\/li>\n\n\n\n<li>Flash autoris\u00e9<\/li>\n\n\n\n<li>Test requirements<\/li>\n\n\n\n<li>Packaging and cleanliness requirements<\/li>\n\n\n\n<li>Exigences en mati\u00e8re de tra\u00e7abilit\u00e9<\/li>\n\n\n\n<li>Change-notification requirements<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">When the materials have not yet been selected, ask the supplier to propose and test at least two compatible LSR-to-PC combinations.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Supplier Qualification Questions<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Ask the LSR overmolding supplier:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Which self-bonding LSR grades have you molded onto PC?<\/li>\n\n\n\n<li>Which exact PC grades have been validated?<\/li>\n\n\n\n<li>Can you provide peel-test samples?<\/li>\n\n\n\n<li>Do you use insert molding or two-shot molding?<\/li>\n\n\n\n<li>How do you control insert temperature?<\/li>\n\n\n\n<li>How do you prevent PC surface contamination?<\/li>\n\n\n\n<li>Is primer required?<\/li>\n\n\n\n<li>Is plasma treatment required?<\/li>\n\n\n\n<li>How do you monitor LSR mixing ratio?<\/li>\n\n\n\n<li>How do you control cure inhibition?<\/li>\n\n\n\n<li>What mold coatings are used?<\/li>\n\n\n\n<li>How do you inspect the bond line?<\/li>\n\n\n\n<li>Can you conduct peel, pull, and leak testing?<\/li>\n\n\n\n<li>How do you manage material changes?<\/li>\n\n\n\n<li>Can production lots be traced to both raw-material batches?<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Conclusion<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Successful self-bonding of LSR to polycarbonate depends on the complete material and process system.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The most important rules are:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Select the LSR and PC as a tested pair.<\/li>\n\n\n\n<li>Do not assume that all PC grades behave the same.<\/li>\n\n\n\n<li>Keep the bonding surface clean and controlled.<\/li>\n\n\n\n<li>Design the joint to resist shear rather than peel.<\/li>\n\n\n\n<li>Add mechanical locking for critical applications.<\/li>\n\n\n\n<li>Protect bond edges from user handling and fluid pressure.<\/li>\n\n\n\n<li>Balance mold temperature, insert temperature, cure time, and PC heat resistance.<\/li>\n\n\n\n<li>Test actual production geometry, not only material plaques.<\/li>\n\n\n\n<li>Validate the bond after aging, chemicals, thermal cycling, and sterilization.<\/li>\n\n\n\n<li>Control every material and process change.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Primerless self-bonding LSR can reduce assembly steps and support automated production, but reliable adhesion must be demonstrated with the exact materials, tooling, process window, and service conditions intended for the final product.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Foire aux questions<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Does every self-bonding LSR adhere to polycarbonate?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">No. Self-bonding LSR grades are developed for selected substrates. The exact LSR and PC combination must be tested before mass production.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Is primer required when overmolding LSR onto PC?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Not always. A compatible self-bonding LSR may adhere to PC without primer. Primer may be required when the material pair does not provide sufficient primerless adhesion.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Can plasma treatment improve LSR-to-PC adhesion?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">It may improve adhesion in selected systems, but the treatment parameters and maximum delay before molding must be validated.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What is the strongest LSR-to-PC joint design?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">A wide interface loaded mainly in shear, combined with protected edges and mechanical interlocking, generally provides a more robust design than a thin exposed edge loaded in peel.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Why does the silicone peel away cleanly from the PC?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Clean separation indicates adhesive failure. Common causes include incompatible materials, contamination, insufficient heat, short cure time, low insert temperature, or inadequate surface treatment.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What is cohesive failure?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Cohesive failure occurs when the silicone tears while some silicone remains attached to the PC. It indicates that the interface is stronger than the silicone at the failure location.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Can a PC-LSR assembly be steam sterilized?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Some material combinations are suitable for repeated steam sterilization, but compatibility is grade-specific. The complete molded assembly must be tested after the intended number of cycles.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Should mechanical locks be added when using self-bonding LSR?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Mechanical locks are recommended for critical areas exposed to peel, pressure, repeated flexing, or safety-related loads. They provide additional retention if chemical adhesion weakens.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Can an internal mold-release additive in PC affect adhesion?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Potentially. Additives can change the surface characteristics of the plastic. The exact resin grade, color, and additive package should therefore be tested as part of the approved material combination.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">How should adhesion be tested?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Use a defined peel, tensile pull, push-out, or functional test that represents the real product load. Record both maximum force and failure mode.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">SEO Information<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>SEO Title:<\/strong> Self-Bonding LSR to PC: Adhesion Methods &amp; Design Rules<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Meta Description:<\/strong> Learn how to bond self-adhesive LSR to polycarbonate using primerless materials, primers, plasma treatment and mechanical locks, with practical mold-design and testing rules.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>URL Slug:<\/strong> <code>\/self-bonding-lsr-to-pc-adhesion-design-rules\/<\/code><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>TAGS:<\/strong> self-bonding LSR,LSR to polycarbonate,LSR overmolding,polycarbonate overmolding,primerless LSR,silicone plastic bonding,LSR adhesion,PC silicone overmolding,two-shot silicone molding,medical LSR overmolding,custom LSR parts,LSR bond testing<\/p>","protected":false},"excerpt":{"rendered":"<p>Self-bonding liquid silicone rubber overmolded onto polycarbonate can combine a rigid structural component with a flexible sealing, cushioning, gripping, or insulating surface in one integrated part. This hard-soft combination is widely considered for medical devices, respiratory products, electronics, wearable devices, waterproof housings, optical components, automotive sensors, connectors, and fluid-handling assemblies. Polycarbonate provides the rigid supporting [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":2549,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"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":"","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":[1],"tags":[2018,2025,2021,2017,2020,2024,2023,2026,2022,2007,2019],"class_list":["post-2548","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry-news","tag-cielab-silicone-color","tag-colored-medical-silicone","tag-delta-e-color-matching","tag-lsr-color-masterbatch","tag-lsr-color-validation","tag-medical-grade-silicone-colorant","tag-medical-lsr-color-matching","tag-medical-lsr-molding","tag-medical-silicone-pigments","tag-medical-silicone-purity","tag-sterilization-color-change"],"_links":{"self":[{"href":"https:\/\/www.fhysilicone.com\/fr\/wp-json\/wp\/v2\/posts\/2548","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fhysilicone.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fhysilicone.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fhysilicone.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fhysilicone.com\/fr\/wp-json\/wp\/v2\/comments?post=2548"}],"version-history":[{"count":1,"href":"https:\/\/www.fhysilicone.com\/fr\/wp-json\/wp\/v2\/posts\/2548\/revisions"}],"predecessor-version":[{"id":2550,"href":"https:\/\/www.fhysilicone.com\/fr\/wp-json\/wp\/v2\/posts\/2548\/revisions\/2550"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.fhysilicone.com\/fr\/wp-json\/wp\/v2\/media\/2549"}],"wp:attachment":[{"href":"https:\/\/www.fhysilicone.com\/fr\/wp-json\/wp\/v2\/media?parent=2548"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fhysilicone.com\/fr\/wp-json\/wp\/v2\/categories?post=2548"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fhysilicone.com\/fr\/wp-json\/wp\/v2\/tags?post=2548"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}