Laminating film is a film bonded across its full surface to another material, by an adhesive, by heat or by its own adhesive layer. What it means in practice depends on the industry. In print finishing it is a PP or PET film of 12 to 30 µm that protects paper and board (Druckmarkt, issue 110). In the graphics trade it is a double-sided mounting film for photos and prints, 0.07 mm thick without the liner (igepa, MasterMount KAP data sheet). In electrical engineering it is the polyester film inside a laminated insulating material: bonded to 50 µm aramid paper, the composite reaches thermal class F at 155 °C (SynFlex, SynTherm NP/50 data sheet). This article sorts out the meanings, explains processes and adhesives and shows what lamination does for an insulating material and what it does not. We convert laminated film composites from our insulation materials into rolls and die-cut parts, but we do not sell mounting films for photos and posters.
Laminated insulating film from GOBA: supply forms, thicknesses and enquiry
GOBA supplies Laminated insulating film from a single piece, as material or as a finished part to your drawing.
- Supply forms
- Roll and slit roll, Sheet and board, Cut-to-size, Die-cut part to drawing, Formed part (folded, embossed or bent)
- Thicknesses
- To your specification. GOBA processes materials from 7 µm to 3 mm.
- Versions
- Laminated insulating films such as NMN, NKN and DMD, made of polyester or polyimide film with aramid paper or nonwoven. As die-cut parts also self-adhesive or kiss cut on a carrier liner.
- Slit rolls
- Widths from 5 to 1,600 mm, tolerance ±0.1 mm, cores of 25, 55, 76 or 152 mm
- Die-cut and formed parts
- Material thickness 0.023 to 3.0 mm, dimensions up to 1,000 × 2,000 mm
- Quantity
- From 1 piece, from sample to series
- Lead time
- Two weeks at most when the material is in stock
What we need for your quotation
- Drawing or dimensions
- Quantity
- Material and thickness
For rolls also width, length, core diameter, core material (for example plastic) and tolerances.
Laminating terms mean different things in different industries
In process terms, laminating means bonding two or more webs across their full surface with a laminating agent, usually an adhesive, and DIN 8593-8 classes it as adhesive bonding (verpackungswirtschaft.de). German has two words for it, kaschieren and laminieren, and the trade sources draw the line between them in different places. Ask two suppliers and you often get two answers.
| Source | Kaschieren means | Laminieren means |
|---|---|---|
| Wikipedia, verpackungswirtschaft.de | bonding opaque layers, such as printed board onto grey board | at least one layer is transparent, such as gloss film on a print |
| Druckmarkt (print finishing) | applying film to one side of the printed sheet | enclosing the material on both sides, with no open cut edge |
| Neschen (maker of filmolux and gudy) | umbrella term for processing self-adhesive and heat-seal films | protecting with a one-sided adhesive film; sealing on both sides is called hot sealing there |
| Electrical insulation (IEC 60626-1) | bonding film to paper, nonwoven or metal | the result is a laminate, called a combined flexible material in the standard |
Neither word is good enough for a purchase order. Write down the build-up instead: which layers in which order, the thickness of each, whether an adhesive is exposed and what covers it. “PET 50 µm, aramid paper 50 µm on one side” reads the same to every manufacturer, “laminated film” reads differently to each.
Seven products sold as laminating film
A search for the German term Kaschierfolie leads to shops for art supplies, print finishing, office equipment and dental technology. The table sorts out what each of them means.
| Meaning | Build-up and key figure | Use |
|---|---|---|
| Mounting film, double-sided adhesive | 12 µm PET, acrylic on both sides, 0.07 mm without liner (igepa) | mounting photos and prints onto boards |
| Thermal laminating film on the roll | 12 to 15 µm BOPP plus 6 to 12 µm EVA adhesive, laminated at 100 to 130 °C (arrsys) | book covers, brochures, folding cartons |
| Laminating film and pouches | PET with EVA, 80 to 250 µm per half, processed at 60 to 80 °C (Wikipedia) | ID cards, menus, notices |
| Furniture and decor film | finish or decor film, laminated onto the board with white glue, UF resin or hotmelt at 20 to 35 m/min (Hymmen) | furniture fronts on chipboard and MDF, flooring |
| PE laminating film | flat film of LDPE, HDPE or EVA (Dürrbeck) | moisture barrier on insulation boards, carrier for bitumen sheets |
| Dental laminating film | transparent, 0.15 mm thick, round with 125 mm diameter (Scheu-Dental) | protective cover for study and orthodontic models |
| Laminated insulating film | polyester film bonded to pressboard, aramid paper, nonwoven or metal (SynFlex, Müller-Ahlhorn) | slot, layer and phase insulation, shielding |
Mounting films for photos, laminating pouches, furniture and dental films are available from art and graphics suppliers, office retailers and dental distributors. For printers and converters we supply polyester and PP films for laminating applications, as rolls or sheets that suit standard laminating systems, described on our page for the printing industry. From here on, the article is about laminated insulating film and the processes behind it.
How laminating film bonds: six processes
Two questions separate the processes: where does the adhesive come from, and does it need heat? The six below are the common ones in printing, packaging and insulation.
- In wet lamination the webs meet while the adhesive is still wet. It is usually a water-based dispersion, so one layer has to absorb the water, as a rule paper or board. Industrial lines run well above 100 m/min (Druckmarkt).
- Dry lamination uses a solvent-based adhesive whose solvent evaporates in a drying tunnel before the webs meet. It is the process for two closed layers, film on film or film on aluminium.
- Solventless lamination uses a polyurethane with 100 % solids that cures chemically. There is no drying tunnel, and 1.0 to 3.0 g/m² of adhesive is enough, against 2.5 to 5 g/m² for solvent-based systems (verpackungswirtschaft.de).
- In extrusion lamination, molten polyethylene is itself the adhesive and bonds the webs as it cools.
- Thermal laminating film comes precoated with a hotmelt, usually EVA. BOPP-EVA film laminates at 100 to 130 °C (arrsys), heat-seal films for graphics at 85 to 120 °C (Neschen), and pouches in an office laminator at 60 to 80 °C (Wikipedia).
- Cold laminating film carries a pressure-sensitive adhesive, usually acrylic, that bonds under pressure at room temperature. Neschen uses water-based acrylic dispersions in its mounting films.
Thermal is the cheaper choice in materials: film and adhesive for hot roll lamination often cost only about half as much as cold laminating film (Wikipedia, Lamination). Cold is right as soon as the substrate cannot take the heat. Neschen gives a clear example: inkjet inks boil between 70 and 100 °C, so residual moisture evaporates under a heat-seal film and leaves bubbles. For inkjet prints and photos the manufacturer therefore recommends cold lamination only. In insulation, the film and paper composite arrives fully laminated from the manufacturer. At most, the converter adds a self-adhesive finish.
The laminating adhesive decides what the composite can take
Film and paper have data sheets, while the adhesive between them is often just a footnote. Yet it determines adhesion, temperature limit and ageing of the whole composite.
| Adhesive | Process | Key figure | What to watch |
|---|---|---|---|
| Polyurethane, solvent-based | dry lamination | 2.5 to 5 g/m² dry | needs a drying tunnel and solvent |
| Polyurethane, solventless | chemical cure | 1.0 to 3.0 g/m² | aromatic systems hydrolyse from about 105 °C, so aliphatic ones, stable up to 135 °C, are used for sterilisation |
| Acrylic pressure-sensitive adhesive | cold lamination, mounting films, tapes | 30 g/m² per side, 7 N/25 mm after 20 min, 9 N/25 mm after 24 h | bond strength rises over 24 hours, upper limit in the data sheet around 150 °C |
| EVA hotmelt | thermal lamination | 6 to 12 µm layer | thermoplastic, check for warm installation sites |
| Modified acrylic adhesive, cured | flexible copper laminates on Kapton | 13 to 51 µm layer | supplied fully cured |
Sources: verpackungswirtschaft.de for polyurethane, igepa MasterMount KAP (tested to AFERA 5001) for acrylic, arrsys for EVA, DuPont Pyralux LF for the copper laminate. For insulating materials this leads to a rule we also explain in the article on composite materials: the adhesive layer has to hold the same thermal class as the plies, otherwise the adhesive sets the class. A PET and Nomex composite such as SynTherm NP/50 carries class F at 155 °C to IEC 60085 as a system, although PET on its own runs in class B at 130 °C. So ask for the thermal class of the finished composite, not that of its plies.
Self-adhesive and double-sided laminating film, layer by layer
A double-sided laminating film is itself a composite of four layers. The data sheet of igepa MasterMount KAP lists them from top to bottom:
- open adhesive layer of pure acrylic, 30 g/m², permanent
- carrier of transparent PET film, 12 µm
- second adhesive layer, 30 g/m², removable in this version
- liner of coated release paper, 90 g/m²
Without the liner that makes 0.07 mm. The manufacturer states a temperature range of -40 to +150 °C, processing from 10 °C and a shelf life of two years. A transfer adhesive does without a carrier: 3M 467MP consists only of 58 µm acrylic adhesive on a liner and is rated from -40 to 149 °C (data sheet values via DigiKey). The Zenith mounting film sold in art shops follows the same build-up with 12 µm PET and pure acrylic.
In insulation the same idea is called self-adhesive finishing. Müller-Ahlhorn offers a pressboard, PET film and pressboard laminate as a self-adhesive die-cut part as well. We supply insulating parts as stamped and bent parts, flat, pre-bent, self-adhesive or with defined tape application, and on request as a kiss cut on a carrier liner so that assembly can peel the part off directly. Choose the tape for the installation site. The 150 °C in a mounting film data sheet describes a service range, and that is not a thermal class to IEC 60085. On an insulating part the tape needs proof of the continuous temperature at the installation site, all the more on an aramid paper part for class H at 180 °C. That is why we ask for the thermal class with every enquiry.
Laminated insulation: what the paper ply does and what it does not
In motors and transformers, laminating film is usually polyester film bonded to pressboard, aramid paper or nonwoven. The film blocks the voltage. The paper ply absorbs impregnating resin, protects the film at the edges of the lamination stack and, with aramid, raises the thermal class (SynFlex, SynKraft KP and SynTherm NP/50 data sheets). The SynTherm NP/50 range shows which ply carries the kilovolts: the aramid paper stays at 50 µm in every thickness, and the breakdown value grows with the film.
| Material | Build-up | Total thickness | Breakdown per data sheet | Test basis | Thermal class |
|---|---|---|---|---|---|
| SynTherm NP/50 | PET 23 µm, Nomex 50 µm | 0.08 mm | 5 kV | IEC 60626-2 | F (155 °C) |
| SynTherm NP/50 | PET 50 µm, Nomex 50 µm | 0.10 mm | 7 kV | IEC 60626-2 | F (155 °C) |
| SynTherm NP/50 | PET 125 µm, Nomex 50 µm | 0.18 mm | 12 kV | IEC 60626-2 | F (155 °C) |
| SynTherm NP/50 | PET 250 µm, Nomex 50 µm | 0.30 mm | 18 kV | IEC 60626-2 | F (155 °C) |
| SynKraft KP | PET 50 µm, pressboard | 0.10 mm | 10 kV | IEC 60626 | B (130 °C) |
| Nomex 410, on its own | aramid paper 50 µm | 0.05 mm | about 0.9 kV (18 kV/mm) | ASTM D149 | up to 220 °C |
| HOSTAPHAN RN, unlaminated | PET 125 µm | 0.125 mm | 23 kV | DIN 40634 | B (130 °C) |
Sources: SynFlex, SynTherm NP/50 (06/24) and SynKraft KP (10/18); DuPont, Nomex 410 technical data sheet; HOSTAPHAN RN according to Mitsubishi in the SynFlex product data sheet (06/24). With the paper ply unchanged, the value rises from 5 to 18 kV as the film grows from 23 to 250 µm. The 50 µm aramid paper itself reaches just under 1 kV. The bare 125 µm film appears with 23 kV, almost twice the figure of the composite with the same film. That does not show that lamination weakens the film, because film and composite are tested to different standards. How much the test moves the number is clear from the same 50 µm film: 10 kV in SynKraft KP, 7 kV in SynTherm NP/50, 7.7 kV in a NEPTCO shielding laminate. For design this means the voltage withstand comes from the film thickness. You buy the paper ply for edge protection, resin uptake and, with aramid, the thermal class. Design a composite to its own data sheet and never scale up from the value of the HOSTAPHAN or Mylar core film.
That leaves the objection from purchasing that a laminate costs more than a film. It is true, and our answer is one ply for as long as it is enough. A composite pays off only when two requirements apply at once, such as voltage withstand and edge protection in a tight slot, or class F with a PET core. The laminate types with build-up and minimum voltage are covered in the articles on DMD laminate, NMN laminate and insulating paper for electric motors.
Metal-laminated films shield on one side and insulate on the other
Aluminium or copper laminated onto PET gives a film that conducts on the outside and insulates on the inside. The shielding laminate NEPTAPE 973 consists of 51 µm polyester film and 9 µm aluminium, is 61 µm thick, has a resistance of 350 Ω/km at 10 mm width, and its PET ply withstands 7.7 kV (NEPTCO data sheet). It wraps and shields multipair cables. For flexible circuit boards DuPont laminates copper onto Kapton of 13 to 127 µm with 13 to 51 µm of acrylic adhesive (Pyralux LF).
We process PET-aluminium composite film for cable sheathing and enclosure linings in EMC shielding film slitting, along with copper foil from 6 to 200 µm, bare or with a conductive adhesive layer. We pay close attention to burr-free cut edges, because even the slightest deformation impairs contact and with it the shielding effect. The physics is explained in the article on EMC shielding, the metal in the article on copper foil.
Slitting and die-cutting laminated film: five sources of failure
A composite behaves differently under the blade than a single film, because the cut runs straight through the adhesive joint. Five points matter:
- Adhesive at the cut edge. If adhesive squeezes out of a self-adhesive film, the edges stick together on the finished roll and the film is hard to unwind. Blade setting and cutting method have to prevent adhesive transfer.
- Delamination. In shear cutting, the circular blades put the adhesive layer under shear. If the lamination is weak or the blade gap too wide, the edge opens. Blade gap and winding tension have to suit the build-up, and the first cut shows whether the joint stays closed.
- Cutting depth in kiss cutting. The tool separates face material and adhesive, and the liner must stay intact, otherwise the matrix stripping tears parts away with the waste.
- Aged surface. Corona treatment makes film bondable, but its effect fades over time. Freshly treated film is therefore laminated promptly, with details in the article on corona discharge.
- Flatness. Thin material laminated on one side curls, and laminating machines counter this with an anti-curl unit (Druckmarkt). For sheets and flat die-cut parts, flatness therefore belongs in first article inspection.
Laminates and multilayer composites go through our contract slitting into rolls from 5 to 1,600 mm wide with a tolerance of ±0.1 mm, wound on cores of 25, 55, 76 or 152 mm. Mother rolls up to 1,000 kg are loaded hydraulically, and we slit at up to 400 m/min, depending on the material. In stamping and forming we process material from 0.023 to 3.0 mm into parts up to 1,000 x 2,000 mm, with steel rule dies for samples and small batches and solid steel tools for series.
Requesting laminated film from GOBA
We supply laminated insulating films such as NMN, NKN and DMD, self-adhesive insulating parts and slit metal-laminated films. Delivery forms are roll, sheet, cut piece, die-cut part and formed part, from a single piece and within two weeks at most when the material is in stock. To get the quotation right the first time, we need:
- drawing and quantity, for series the annual demand
- the build-up with all plies, the thickness of each ply and the total thickness
- the thermal class at the installation site, so that laminate and adhesive match
- whether the part is self-adhesive, with which liner, kiss cut or cut through
- for rolls also width, running length, core diameter, core material and tolerances
When it comes to choosing laminate, thermal class and adhesive, our technical consulting teamcan help. If the drawing only says “laminated”, we ask which plies are meant.
