CPL Laminate:
Features and Applications
What is CPL?
Composition
- One or more layers of kraft paper impregnated with phenolic resin, forming the core of the product and providing the laminate with strength and stability.
- A decorative layer, placed on top of the kraft paper, which represents the visible part of the laminate. It consists of decorative paper impregnated with melamine resin, giving the laminate its aesthetic appearance.
- An optional outer layer, known as an “overlay,” which provides additional resistance. It is usually impregnated with melamine resins and has the capacity to completely dissolve during the formation of the laminate in the press, resulting in a transparent finish.
Phenol is an organic compound derived from oil production. Prolonged exposure to this substance can cause severe damage to both people and the surrounding environment, making it toxic and not sustainable. For this reason, sustainable alternatives have been introduced in the CPL laminate production process, replacing phenol with eco-friendly thermosetting resins like those used by the Puricelli Group: a combination of agricultural urea, melamine, and additives.
PRODUCTION
First, the process begins with the preparation of thermosetting resins, which are then used to impregnate the paper.
In the impregnation phase, kraft paper and decorative paper are presented in rolls that are impregnated using specific machinery: the rolls of paper are immersed in resin tanks and passed through rollers that remove excess resin. The kraft paper, which forms the core of the product, is generally impregnated with phenolic resins or, alternatively, with eco-friendly thermosetting resins. The decorative paper, which represents the aesthetic aspect of the laminate, is impregnated with melamine resins.
After this process, the paper rolls run parallel through special ovens for drying.
Next, the dried, impregnated rolls of kraft and decorative paper are sent to the continuous press. This machine, also known as a “calender” or “belt press,” consists of two parallel steel belts between which the decorative sheet and various layers of impregnated kraft paper are inserted. The press applies constant heat (between 150°C and 170°C) and pressure (between 30 and 70 bar) along the entire length of the laminate, allowing the resins to fully polymerize and bond the paper layers into a single, compact, and resistant material. This continuous pressing process usually lasts only a few minutes and allows for uninterrupted production.
The surface texture (matte, wood effect, ceramic effect, etc.) is imprinted during this phase by press plates designed to impart the desired finish when in contact with the resin. Alternatively, highly resistant “release” papers with embossed structures can be used between the press and the laminate, leaving an imprint upon contact.
At this stage, the CPL laminate is cut to the desired dimensions using high-precision cutting machines. Edges are trimmed, and further processing may be carried out if necessary to adapt the laminate to specific customer requirements.
Finally, quality checks are performed to ensure the final product meets the required standards for quality, durability, color, and finish. The material is then prepared and packed for transport and assembly, ensuring minimal damage during handling.
This continuous pressing process not only ensures uniform quality of the final product but also enables efficient production of large quantities of CPL.
Origins and Evolution
Building on Baekeland’s idea, Emil Liebich further developed the concept by mixing phenol-formaldehyde thermosetting resins with paper, creating a material stable against light and abrasion and non-conductive to electricity.
In the 1920s, the first high-pressure laminates (HPL) were produced by polymerizing kraft paper impregnated with these thermosetting resins between steel plates. Initially, these laminates were mostly technical, used primarily for electrical components.
HPL laminates were later used for the production of decorative panels, making the laminate market even more attractive. Many laminate manufacturers were founded, and existing companies adopted patents and technological know-how for the production of these products, including in Europe. A pioneer in Italy, Puricelli was founded in 1948 and opened its innovative plastic laminate manufacturing plant in Costa Masnaga in 1962.
In the following decades, research, innovation, and the development of new varieties of HPL opened up endless application possibilities across various market sectors, creating a wide range of products.
Over time, the industry sought more efficient and cost-effective materials while maintaining the aesthetic and functional qualities of HPL laminates. From this need, CPL laminate was born, characterized by a continuous production process with controlled pressure, reducing costs and increasing productivity.
In the 1980s, despite skepticism from other manufacturers, Puricelli Group in Italy began producing the first CPL laminates, expanding its offerings with flexible laminates for covering curved surfaces. The first press for processing sheets and rolls of laminates was introduced in their Lombardy plant.
The evolution of this type of product has been driven by growing demand for more functional and decorative materials for furniture and interior design. In the 1950s and 1960s, with the advent of modern design, CPL laminate gained popularity due to its ability to mimic various natural materials such as wood and stone, while being more affordable and easier to maintain. Printing and finishing techniques constantly improved, allowing the production of laminates with increasingly realistic and appealing textures and colors.
Moreover, ongoing technological innovation in materials has led to the development of CPL laminates with advanced properties, such as fire and chemical resistance, offering a wider range of finishes and applications, enabling the creation of durable and versatile surfaces for various uses.
In the 2000s, the increasing focus on sustainability, not just environmental, led to years of research and experimentation to develop sustainable and eco-friendly production methods for laminates, such as using low-formaldehyde-emission resins and paper from sustainably managed forests. One example is the Puricelli Group, which had already introduced water-based resins in the market for laminates several years earlier. In 2007, to protect not only the environment but also the people involved in the production and use of laminates, they introduced a new phenol-free resin.
In those same years, increasingly innovative digital printing technologies enabled the customization of laminates with complex designs and high-resolution images, opening new creative possibilities and, consequently, new applications in interior design: doors, furniture, and countertops.
ADVANTAGES
CPL laminate is designed to withstand heat and humidity, maintaining its structural integrity and appearance over time, thanks in part to the outer protective layer that ensures resistance to water, mold, and bacteria. Its durability is another strong point: it offers a long lifespan due to its resistance to scratches, impacts, and abrasions. Compared to other materials, CPL laminate represents a cost-effective yet high-quality option that does not compromise on aesthetics or functionality.
Easy to work with and install, CPL reduces labor time and costs, making it a convenient choice for many applications.
Therefore, its characteristics of resistance, dimensional stability, robustness, durability, and aesthetic quality, combined with its excellent price, make it an attractive option for architects and interior designers, who choose it also for the numerous variants available on the market.
APPLICATIONS
Continuous press laminate is also perfect for numerous applications on vertical and horizontal surfaces in environments like offices and commercial spaces: partition panels, reception coverings, counters, and work surfaces.
Technical Characteristics
CPL laminate is available in a variety of formats, thicknesses, colors, and textures, making it extremely versatile for different applications in interior design and furnishing.
Thicknesses and Formats
Thinner thicknesses are mainly used for decorative coverings and surfaces that do not require significant structural strength and are less subject to wear, such as wall coverings or curved surfaces. In contrast, thicker laminates offer superior strength, ideal for countertops, furniture, doors, partition panels, cabinet doors, and surfaces that require good resistance to scratches and impacts.
Standard formats of CPL laminate can vary, but panels often have widths ranging from 900 mm to 1800 mm and lengths that can exceed 4000 mm. These dimensions allow great flexibility in the use of the material, facilitating the application on extensive surfaces without the need for intermediate joints that could compromise the aesthetics and functionality of the product.
After pressing, CPL sheets can be cut to the desired width and length directly in line, allowing great flexibility in the final dimensions of the product.
Texture and Digital Printing
It is available in a wide range of colors, and thanks to the introduction of digital printing, panels can be decorated with any graphic or image, even photographic, that the customer desires. Any decoration can be created without limitations, making each project unique.
The technological evolution of recent years has allowed the processing of the overlay (the last resin layer) to achieve a three-dimensional effect, combining high photographic quality used to reproduce the image of the material being replicated with an irregular, rough, or rugged surface that is so realistic it perfectly simulates the look of wood, stone, or concrete.
So, the texture is sometimes designed to give the material a more authentic appearance, imitating and trying to replicate a surface that exists in nature. Other times, applying a particular finish serves to enhance the sensory and aesthetic value.
These surface “roughnesses” also help mask the wear effects that can result from the everyday use of kitchen surfaces, although they should not be too pronounced to avoid trapping dirt. Indeed, the choice of finish should be evaluated not only for its aesthetic value but also based on the intended use of the final product.
In the CPL laminate production cycle, the texture is imprinted during the pressing phase, thanks to the press plates or, alternatively, through “release” papers. A wide variety of textures can be achieved on CPL laminate, with the only limitation being glossy finishes: the glossy effect specifically requires high temperatures and long times, conditions not typical of the continuous laminate production process.
As for colors, there are pre-pigmented decorative papers, or alternatively, these can be dyed to the desired color. For digital printing, the printed decorative paper cannot be impregnated, as the ink would expand, ruining the overall final result. In this specific case, the paper is interlaminated: the decorative print created with digital printing is inserted, and a transparent overlay impregnated with melamine resin is applied on top to provide the necessary grip and ensure the desired print appears on the laminate.
Maintenance and Installation
Ease of maintenance and installation are two particularly relevant advantages of CPL laminates, especially when choosing these products for interior furnishing. Specifically, CPL laminate is a product that, depending on use, maintenance, and environmental conditions, can last many years, from 10 to 20 years, often even longer. Therefore, it is important to know how to clean, repair, and install these laminates to prevent and manage damages that could otherwise be avoided.
How to Clean CPL Laminates
Aggressive or abrasive products commonly used for polishing, such as steel wool and abrasive powder, are not recommended for cleaning laminates, as they may cause scratches or superficial marks, damaging the surface. Similarly, descaling products may contain highly corrosive substances that could damage the laminate.
How to Repair CPL Laminates
Following the specific recommendations of the manufacturer is always the best way to ensure proper maintenance and management of this type of product. Generally, manufacturers provide detailed guides on the use, cleaning, and maintenance of their CPL laminates to maximize the lifespan and performance of the panels.
How to Install CPL
For CPL laminate applications in indoor environments, the most frequently used technique is bonding the laminate to a substrate using water-based two-component adhesives: eco-friendly, non-toxic, and non-harmful glues, ideal for closed environments. Another significant advantage of this method is the ability to achieve a smooth and uniform surface without visible screws or other elements. In some cases, CPL panels can also be mounted using hooking or interlocking systems, reducing the need for glue or visible screws and making the process much faster and more straightforward.
Differences Between CPL Laminates and Other Materials
CPL vs HPL Compact
CPL (Continuous Pressure Laminate) and HPL Compact (High Pressure Laminate) are the two main types of laminate on the market.
In terms of basic materials, their composition is the same, consisting of layers of kraft paper, decorative paper, and protective layers impregnated with thermosetting resins. Both are used for surface cladding and design products, offering a wide range of finishes and colors, allowing for great creative freedom.
However, they have significant differences in terms of production, thickness, and consequently, their applications.
CPL is produced through a continuous process where the layers, impregnated with thermosetting resins, run parallel in coils inside a belt press, where they are pressed together under constant heat and pressure. In contrast, the HPL Compact production process involves stacking these layers as sheets rather than coils, which are then pressed at high pressure and temperature in a multi-layer industrial press. Furthermore, CPL can be cut to the desired dimensions immediately after pressing, while HPL Compact sheets can be cut either before pressing or afterwards.
The CPL production cycle is very rapid, lasting only a few minutes, whereas HPL takes about 40-50 minutes.
CPL is manufactured in thicknesses ranging from 0.1 mm to 1.2 mm, while HPL is available in thicknesses from 0.8 mm to 3 mm for the thin variety, and from 4 mm to 25 mm for the Compact.
So, the continuous production of CPL allows for thinner, flexible, and durable sheets, while HPL Compact’s high-pressure, high-temperature production process results in thicker sheets that are highly resistant to impact and various weather conditions.
In terms of applications, CPL is ideal for surface coverings such as doors, cabinet fronts, and partition panels, while HPL Compact is suited for both interior and exterior environments, such as kitchen countertops, ventilated facades, tables, and flooring.
Additionally, CPL is less expensive to produce because more square meters of the product can be manufactured in the same amount of time.
CPL vs Melamine
CPL and melamine are two materials widely used for decorative surfaces and cladding, but they differ in composition, characteristics, and uses.
Melamine consists of a single layer of decorative paper impregnated with melamine resins, which is usually applied to a chipboard or MDF (Medium Density Fiberboard) panel for cladding. These sheets are then subjected to high heat and pressure, hardening the resin and bonding the decorative paper to the support panel, creating a hard and resistant surface.
Both melamine and CPL are composed of sheets impregnated with melamine resin; however, CPL is made up of multiple compressed and thermoset layers of paper, making it thicker and more resistant than melamine, which consists of only one sheet.
Melamine is produced at lower temperatures and pressures than CPL, using a traditional flat press, making melamine less resistant compared to CPL and more susceptible to scratches, impact damage, and wear over time. Melamine is cheaper than CPL, but its aesthetic range is generally more limited.
Like CPL, melamine is easy to clean and maintain. However, while it offers good resistance to surface moisture, it may not be the best choice in environments with constant humidity or extreme temperature changes, as it can deform or swell, especially if the support panel is compromised.
CPL vs PVC
PVC, which stands for “polyvinyl chloride,” is a plastic material derived from natural raw materials. It consists mainly of chlorine derived from common salt and ethylene obtained from petroleum. This composition and production method is the main difference from CPL, which is made of layers of paper and resins subjected to constant pressure and temperature.
Both CPL and PVC are commonly used for surface cladding.
A shared characteristic of PVC and CPL is moisture resistance, making them suitable for use in environments such as bathrooms and kitchens. They are also easy to clean, maintain, and offer good durability. PVC is also used outdoors, for flooring and wall cladding.
However, PVC can be less resistant to impacts, scratches, and heat compared to CPL, and while its aesthetic qualities have improved over time, it cannot compete with the variety of textures, colors, and realism offered by CPL.
Another difference lies in their environmental impact and sustainability. CPL, being a paper-based product with thermosetting resins, is considered more sustainable than PVC, which is a petroleum-based plastic and can emit volatile organic compounds (VOCs) during production and use.
