L&L Cavity Sealing and Acoustic products provide robust solutions for both cavity- and structure-borne noise reduction, allowing OEMs to comply with the highest vehicle acoustic standards.
Our products are designed to minimize noise entering the truck cab interior by managing noise propagation through and around the body structure, as well as reducing external noise generated by the vehicle when in use. Additional benefits are the elimination of metal body corrosion, thereby enhancing body durability and reducing vehicle maintenance costs.
L&L Seal systems demonstrate excellent adhesion to the diverse mix of substrates employed by CV manufacturers, including steel, aluminum, stainless steel, galvanized steel, glass fiber-reinforced plastics and engineering thermoplastics.
Ultimate NVH performance improvements can be achieved when our sealing, structural, and acoustic technologies are integrated using a ‘total vehicle’ approach. We gladly support our customers with design and engineering expertise in order to optimize vehicle performance using the very latest CAD and CAE systems.
Key solutions include:
- Expandable sealing tapes
- Room temperature curing elastic sealant and adhesives
- Extruded, injection-molded or metal carrier-based baffles
- Weld-through sealing tapes
- Extruded seam sealers
DECI-TEX® engineered sound absorption
L&L DECI-TEX® fiber-based, acoustic technology solutions are precisely tuned and engineered for customer-specific applications.
The primary benefits of the DECI-TEX® product range is the delivery of high acoustic and thermal performance, while being lighter in weight and with less material usage than comparable products. Most of our DECI-TEX® products are fully recyclable and perfectly safe during cab assembly and vehicle use.
Our current DECI-TEX® range includes:
- DECI-TEX® V: Vertically lapped, lofted sound absorption materials
- DECI-TEX® T: Thermoformable acoustic sheet-like materials. DECI-TEX® T can be overmolded with plastics to enable easy integration into larger assemblies
- DECI-TEX® X: Horizontal fiber-oriented structures designed to enhance layered thermal performance
An advantage of the DECI-TEX® Vertical Lap is that the acoustic performance is not too dependent on the thickness of the layer and local compression does not hamper the materials ability to absorb sound. Unlike spun plies or needle punch layers, the structure does not collapse over time and there is no risk of free fibers, so the sides can remain open where maximum acoustic performance is needed.
Unlike many competitors, our DECI-TEX® solutions are available in both part and sheet form.
As the DECI-TEX® technology covers several individual sheet solutions, made from different fibers in different weight and lofting techniques, it is readily possible to combine products within the range in order to further optimize customer solutions.
Typical commercial vehicle applications include:
- Dashboard insulators
- HVAC sound absorbing ducts
- Firewall/noise shields
- Driver and passenger floor mat decouplers (cab interior and engine bay side)
- Headliner acoustic/thermal trims
- Cabin trim
- Bus side-wall noise and thermal insulation
- Pass-by noise absorption solutions
Structural bonding adhesives and flexible sealants
Our adhesive technologies come in two product categories: heat-activated adhesives, for use in production processes where (e-coat) ovens are available for cure, and ambient-temperature cure adhesives.
Our heat-activated adhesives provide a class-leading combination of tensile properties and good elongation, allowing for multi-material bonding. With a deep understanding of metal lubricants, press oil and release agent chemistry, we are able to modify our products so that commonly required cleaning and pre-treatment steps (usually with hazardous chemicals) can be eliminated. As a result, our products reduce process complexity, accelerate cycle times, eliminate waste, and enhance part quality.
Ambient cure adhesives are based on novel acrylate and epoxy technologies. In addition to providing excellent physical properties, allowing for multi-material bonding, the acrylate-based adhesives offer:
- Very low odor
- Low shrinkage (= low read through)
- High peel-resistance (= improved crack propagation resistance)
Our flexible sealants are based on silyl modified polymers and are easy to apply without pre-treatment on most substrate types, give an aesthetic surface where needed, and exhibit high UV and low chalking properties.
L&L strives to develop adhesives with the lowest hazard labels in their respective classes. Certified flame-retardant products are available for bus and train applications.
Benefits of (heat activated) adhesives over welding and mechanical fastener systems in body-in-white solutions:
- Substrates that are incompatible with welding processes (e.g. plastics or composites to metals) can be bonded
- Stresses and impacts are distributed over a much wider area
- Elimination of corrosion associated with holes in galvanized or painted surfaces
- Reduced risk of galvanic or contact corrosion
- Elimination of brittle fracture or stress cracking associated with certain welding processes
Composite Body Solutions (L&L CBS and CCS)
L&L’s CBS and CCS structural reinforcement technology enables reduced weight while maintaining or improving vehicle durability, stiffness, crash worthiness, and therefore the overall truck and bus body structure performance.
Crash absorption and crash energy regulations and expectation have increased over the last few years and will continue to increase in the years to come. At the same time, truck and bus manufacturers are confronted with increasing fuel efficiency legislation or pollution constraints. Although adding metal to the cab can be a solution to crash energy absorption, it increases the weight of the cab, and thus leads to higher fuel consumption. Our unique expertise in formulating high-performance expandable structural adhesives provides customers with novel systems that provide optimum reinforcement exactly where it is needed in the vehicle structure without adding weight. When vehicles are designed with our solution from the beginning, in most cases there is no cost penalty either.
L&L has a detailed understanding of the design and engineering requirements of current and forthcoming CV crash safety and acoustic regulations. Using the latest material modeling and computer-aided/finite element analysis software, we have significant expertise in helping customers to optimize vehicle design using L&L Reinforce systems to demonstrate improved safety and lower structure-borne noise while also demonstrating reductions in overall vehicle weight.
L&L Structural Reinforcement technologies are available in several forms to suit a customer's vehicle assembly and design criteria. The dry-to-the-touch structural adhesive is pre-applied to either injection-molded carriers, stamped metal carriers or thermoset SMC carriers. In all cases, final assembly involves a heating step, and require e-coat capabilities at the truck manufacturer.
L&L Continuous Composite Systems:
Continuous composite systems are a highly structural product that can be used on its own to replace metal parts where weight is an issue, e.g. replacing steel or aluminum profiles. Compared to steel, 60 % of the weight can be reduced in many cases, compared with 30 % for aluminum. In practice, however, the higher price for composite compared to metal can only be overcome by combining multiple functions or profiles in one composite part. Composite parts do not corrode, are thermally and electrically insulating, and more than 1 material can often be formed in one die to combine profiles. Profiles can be overmolded by injection molding to increase their functionality as well.
When the CCS parts are used as a carrier for our dry-to-the-touch adhesives, they become a special form of the CBS platform and they can reinforce long, straight structures effectively.
Composite Panel Stiffener
L&L Products Composite Panel Stiffener is an epoxy-based, high expanding structural adhesive contained within a fiberglass reinforcement. It is designed to provide improved local reinforcement and NVH and specifically to deal with excessive panel vibration and noise issues. The product is heat-activated and therefore requires e-coat capabilities.
As a result of detailed analysis, our engineers can determine the ideal size and positioning of the Composite Panel Stiffener in order to provide our customers with optimal pricing and performance.
While in its green state, the panel stiffener offers excellent substrate adhesion and pliability, which allows for it to adhere around corners. Once heat is applied, the material will expand and cure, allowing for a stiffening patch with extra high performance due to the increased moment of inertia.
Typical application areas include door panels and lower cab reinforcements for truck cabs, as well as reinforcement of front, side and rear walls of buses as well as luggage doors.
Key product attributes:
- High performance stiffening due to increased moment of inertia
- Superior adhesion to a wide range of substrates in green state
- Enables thinner gauge panels to be used thereby saving weight
- Ability to hold around corners
- Price competitive
Heat-resistant DECI-TEX® fiber systems
Increased urbanization means that more and more people will live in cities in the near future. Local authorities are confronted with an increase in mobility in the form of two-wheelers and privately used cars, which leads to emissions of NOX and CO2 and other pollutants. Decreasing air quality leads to unwanted health effects and increasing health-related costs. To reverse this trend, emissions regulations are becoming more stringent. For internal combustion engines to emit less, exhaust gases need to be kept hot for the selective catalyst reduction unit to work effectively. Using its proprietary fiber technologies, L&L has developed fiber-based insulation parts that guarantee low temperature dissipation.
L&L thermal insulation parts are customizable to the layout of each specific exhaust system. They are available with a flexible casing as well as welded hard casings.
The same heat resistant fibers can also be used in pass-by noise insulation parts. Noise is another pollutant from internal combustion engines, and the amount of noise emitted by the truck to the surroundings is actively regulated. Pass-by noise insulation parts are placed in the engine bay to ensure low noise pollution, but as the engines run at increasingly high temperatures to deal with emission legislation, the pass-by noise insulation needs to be able to withstand higher and higher temperatures, sometimes up to 650°C.
L&L has the capability of developing both low- and high-temperature-resistant pass-by noise insulation parts, tuning the fiber-based systems used to each customer's needs.
L&L thermal insulation for exhaust systems:
- Available in both rigid (a metallic leak-proof solution) and flexible casings
- Able to be wrapped around any exhaust shape
- Excellent hot-strength-resistant, non-burning
- Provides anti-friction and air-pockets for improved retention of heat along the length and thickness of the insulation
- Non-toxic with excellent chemical resistance against grease, water, and mud