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Aa
Absorber
Absorbers are materials or constructions that absorb sound. Porous foams and fibrous materials are often used to absorb airborne sound. Tough plastic heavy foils are applied to solid structures such as thin-walled metal sheets to absorb structure-borne sound.Absorber classes
Acoustic elements are assigned to one of the absorber classes A, B, C, D or E according to a procedure defined in DIN EN 11654, which is based on the respective assessed sound absorption coefficient. The choice of class depends on the acoustic requirements of a room, as the materials of the various absorber classes are used to supplement the sound absorption already present in rooms depending on the frequency, so the type of material and the extent to which acoustic elements are required depends on the type of use of a room. As balanced room acoustics also require the reflection of sound waves, sound-reflecting acoustic panels are also manufactured, which are categorised as unclassified.A highly absorbent, weighted sound absorption coefficient αw: 0.90 ... 1.0 B highly absorbent, weighted sound absorption coefficient αw: 0.80 ... 0.85 C highly absorbent, weighted sound absorption coefficient αw: 0.60 ... 0.75 D absorbent, weighted sound absorption coefficient αw: 0.30 ... 0.55 E low absorbing, weighted sound absorption coefficient αw: 0.15 ... 0.25 not classified, weighted sound absorption coefficient αw: 0.00 ... 0,10Absorbtion
Absorption (damping) comes from the Latin and means to suck in or devour. Absorption is the absorption of sound waves by an absorbing material.Acoustics
The theory of sound and mechanical vibrations is called acoustics.Ageing
Ageing is the gradual destruction of elastomers by oxygen, ozone, light, heat, moisture and high-energy radiation, which individually or together can cause progressive irreversible damage.Airborne sound
Airborne sound is sound that propagates in the air by means of sound waves.Audible range
The human ear can perceive sounds in a frequency range from around 16 to around 16000 Hertz.
Bb
Building acoustics
Building acoustics deals with the effects of structural conditions on the propagation of sound between building rooms and between the interior of the room and the outside world. The following sub-areas of building acoustics are covered: structure-borne sound, airborne sound insulation, sound insulation of technical and sanitary facilities.
Cc
Causation of vibrations
Moving parts on machines, devices, appliances and vehicles generate vibrations and noise. They are caused by uneven or rotating movements of unbalanced masses. Vibrations and shocks have a disturbing effect on the environment in the form of shocks and noise.Cell structure of foam
Depending on the material type or material treatment, the cell structure is open, semi-open or closed. Closed-cell foams are, for example, cellular rubbers or cross-linked PE foams. Open-cell foams are usually PUR foams. During subsequent material treatment, such as reticulation, the cell walls are removed by means of a controlled gas explosion, resulting in open or semi-open cells in filter foams, for example.Cold foam
The best and most valuable of the foams is cold foam. It can be compared to natural latex foam and is usually used in the block foam process. Cold foam is a polyether foam which, in contrast to standard foam, is classified as a highly elastic HR foam (HR = High Resilent). Cold foam has the following advantages: open-cell, high air permeability, breathable, irregular, coarse pore structure, open-cell, high elasticity with a supple feel.Compression hardness
Compression hardness, also known as compression resistance, is the pressure required to compress a foam. With a compression hardness of 60, 6.6 kPa (kiloPascal) is required to compress the foam to 40%. The compression hardness of a foam describes its strength.Compression set
The compression set (compression set) is a measure of how elastomers behave during prolonged, constant compression set and subsequent relaxation. A DVR of 0 % would mean that the rubber fully regains its original thickness, a DVR of 100 % indicates that the rubber was fully deformed during the test and shows no recovery.Compression transfer molding process (CTM)
In the compression transfer molding (CTM) injection molding process, rubber compound is injected through channels into the mold cavities as the press is fed. CTM molds are made up of three parts (upper, middle and lower part). As the compression transfer moulding (CTM) process generates frictional heat through injection into the cavities, the vulcanization time is reduced. The transfer molding process is particularly suitable for the production of small rubber moulded parts in moulds with many cavities.Compressive stress rubber
Under compressive stress, the limit of linearity is 15% deformation in relation to the rubber layer thickness. The influence of the shape factor must be taken into account when designing a rubber spring for the compression range. The shape factor is the ratio of the action pressure area to the free compression area of the rubber spring. This is due to the prevented transverse expansion and thus the variable modulus of elasticity c of the incompressible rubber material.CR Chloroprene rubber
CR chloroprene rubber, is also very common under the trade name Neoprene. CR rubber achieves quite good ozone and ageing resistance but only satisfactory oil resistance. Thanks to the high chlorine content, CR rubber has good flame resistance. Wherever good flame resistance, good chemical resistance and good aging properties are required, CR chloroprene rubber can be used.Cross-linked foam
In a cross-linked foam, the molecular chains branch out and are chemically and physically bonded together through polymerization. This cross-linking results in an increase in mechanical and thermal resilience. The cross-linked foams in our range include Plastazote PE foam, for example.Cross-linked foam
The cross-linked foam is chemically and physically bonded together by polymerization, the molecular chains branch out, which leads to an increase in mechanical and thermal resilience.
Dd
Decibel (dB)
Decibel (dB) is the unit of volume.Difference between cellular rubber and sponge rubber
Cellular rubber and sponge rubber are often confused; the difference lies in the material properties due to the different manufacturing processes. Sponge rubber has open cells and a dense outer skin. Due to the outer skin, sponge rubber is particularly suitable for increased mechanical stress and abrasion. However, if the outer skin of the sponge rubber is damaged, it can soak up water. Cellular rubber has no outer skin, but cellular rubber has closed cells. This means that cellular rubber is always watertight and airtight. Sponge rubber or cellular rubber are foamed rubber qualities (EPDM, SBR, CR, NBR) and can adapt very well to the substrate, which is why they are mainly used for seals.Difference between structure-borne and airborne sound
In simple terms, the propagation medium is the difference between structure-borne sound and airborne sound. Airborne sound propagates through the air in the form of sound waves. Structure-borne sound, however, propagates in solid bodies such as steel, concrete, wood, stone, etc. This includes, for example, impact sound or the noise generated by building services systems.Diffuse and direct sound
Diffuse sound is the sound that is present after reflections from boundary surfaces in rooms.
Ee
Elastomer/metal bond
Continuous quality tests at all processing stages ensure a high and consistent standard for the bond. The final test is a test according to a sampling plan of the adhesive strength by visual inspection at the edge zone at 1.5 - 3 N/mm2 tensile force or even by tearing to destruction. In general, it can be said that elastomer/metal bonds after cross-linking of the elastomer with simultaneous bonding reaction of the adhesive system, statically tested, only show a fracture in the elastomer.Elastomers
Elastomers are dimensionally stable but deformable plastics which return to their original shape after being subjected to tensile or compressive stress. Elastomers are also commonly referred to as rubber.EN 45545
The rail vehicle standard DIN EN 45545-2 (CEN TS 45545-2) is a European rail vehicle standard. This standard completely replaces national standards such as DIN 5510. The set of requirements R1 attached to the standard is one of the most difficult to fulfill in terms of test methods. The operating class 1-4 attached to the standard regulates the hazard level HL 1-4.EPDM Ethylene propylene diene rubber
EPDM rubber has good resistance to oxygen, ozone and temperature. EPDM is also characterized by above-average chemical resistance. However, its resistance to mineral oil and grease is rather poor. Thanks to its very good resistance to weathering and hot water, EPDM rubber is used as profiles and sealing elements.
Ff
FDA compliant
The FDA (Food and Drug Administration) is an American supervisory authority that is responsible for monitoring all goods marketed in the USA. This also includes all imports into the USA, which is why the regulations of the FDA authority are also important for European manufacturers. These regulations are binding for exporters to the USA. The FDA has extremely strict requirements in the food sector, where a large number of rubber and plastic products are used and therefore also come into contact with food or drinking water. The materials must not release any substances into the food. This means that all plastics that come into contact with food should be FDA-compliant.Flowing and setting a spring element
Flow is the time-dependent increase in the elastic spring deflection of a spring under constant load. It is a consequence of the reduction in restoring force. The increase in spring travel, which has already reached half its value after 24 hours of loading, can usually be neglected in practice and does not affect the vibration behavior. The permanent residual deformation, including the settling that depends on the number of load cycles and the amplitude and is comparable to the flow, is less than 10% of the elastic spring deflection with elastically good elastomer qualities.Foaming process
Depending on the type of foam production, a distinction is made between: - In physical foaming, the material is foamed by a physical process; - In chemical foaming, gases are produced during the production of the plastic, which foam up the material. - In mechanical foaming, air is stirred into the resin or paste to be foamed and the foam solidifies due to the cross-linking of the resin.FPM Fluororubber
FPM fluoro rubbers are also known under the brand name Viton. FPM rubber is flame-retardant and, of all elastomers, has outstanding resistance to high temperatures, ozone, oxygen and chemicals.Frequency
Frequency is the number of oscillations of the sound per second (Hertz Hz).
Hh
Heavy foil
Heavy foils are mainly used for the soundproofing of metal and plastic components that are exposed to strong vibrations. By applying heavy foils, the mass of these elements is increased and a reduction in noise is achieved. This is known as structure-borne noise damping. Heavy foils made of bitumen or bitumen-free plastic are also suitable for airborne sound insulation.Hertz
Unit of frequency. 1 Hz = one complete oscillation per second.Hysteresis damping
All elastomer materials have hysteresis damping. The damping depends on the rubber quality, temperature, deformation speed, deformation acceleration, shaping and type of stress.
Ii
Impact sound
When floors are walked on, structure-borne sound is stimulated, some of which is emitted as airborne sound. This radiation can be reduced by impact sound insulation.Impedance tube
The impedance tube is used to measure the absorption coefficient of a material at vertical sound incidence.Installation sound
Installation noise is the noise caused by heating and air-conditioning units, fans, hydraulic systems and elevators.Insulation
Insulation is the containment of airborne or structure-borne noise or vibrations.Insulation of structure-borne sound
The known effects of structure-borne noise make it imperative to create effective vibration insulation. A technologically relatively simple type of structure-borne sound insulation is achieved by installing an intermediate layer as close as possible to the source of interference, which interrupts the path of the sound vibrations. For example, motors are placed on specially designed vibration isolation bodies, which thus become a vibration system that is virtually independent of the surroundings or support. The same applies to building floors that are periodically subjected to powerful horizontal and vertical impulses at the same time, which are then made vibration-free both horizontally and vertically by means of insulation.
Mm
Main excitation frequency
It is essential to correctly identify the main excitation frequency that dominates in each vibration system. The majority of vibration-generating systems that require elastic mounts are combinations of drive motors and driven machines. In most cases, other vibrations with higher frequencies are superimposed on the fundamental vibration of driven machines and aggregates, which arise from the unbalanced movements of masses and cause vibrations that can also occur non-uniformly or periodically. In this way, the excitation frequencies can be determined fairly accurately from the rotational speeds, as is the case with motors. In many other cases, such as textile machines and machine tools, they are almost impossible to determine by calculation and vibration measurements should be carried out.MVSS
Acoustic foams with the FMVSS 302 fire protection class are mainly used in vehicle construction and mechanical engineering. Flame retardants are added to the foam to reduce the speed at which flames spread in the event of a fire. (4 inches/minute) The test procedure introduced in the USA as the Federal Motor Vehicle Safety Standard (FMVSS 302) is used by most car manufacturers worldwide.MVSS 302
Acoustic foams with fire protection class FMVSS 302 are mainly used in vehicle construction and mechanical engineering. Flame retardants are added to the foam to reduce the speed at which flames spread in the event of a fire. (4 inches/minute) The test procedure introduced in the USA as the Federal Motor Vehicle Safety Standard (FMVSS 302) is used by most car manufacturers worldwide.
Nn
Natural or synthetic rubber
To roughly define natural rubber or synthetic rubber, natural rubber (NR) is a naturally produced material that is a model for all synthetically produced elastomeric materials in terms of its structure. NR has a very high tensile strength, particularly in the case of soft elastomer qualities, high elasticity, flexibility at low temperatures and outstanding dynamic properties, which are rarely achieved by synthetic elastomers in this combination and therefore still make NR indispensable today for some applications, particularly for vibration isolation systems. Dynamic hardening must also be taken into account when designing elastomer springs. In the case of low-damping elastomer materials such as NR, it can generally be neglected. With high-damping compounds, the dynamic spring stiffness can be several times higher than the static stiffness. However, if extreme demands are placed on a product with regard to certain resistances, including oxidation and damping properties, it is essential to switch to a synthetic rubber.Natural rubber NR
Natural rubber is obtained by tapping rubber trees to obtain a white aqueous milk (latex) containing natural rubber. Natural rubber (NR) is an excellent material and has very high tensile strength, elasticity, flexibility at low temperatures and very good dynamic properties. This extraordinary combination is only achieved to a limited extent by synthetic elastomers, which is why natural rubber is still irreplaceable today for various applications. Additional treatment with protective agents is necessary for greater resistance to ageing and ozone, and NR natural rubber is not resistant to mineral oils and greases. NR is available for hardness ranges Shore A 30-90. Areas of application: Molded rubber parts, rubber bellows, rubber membranes, rubber flat seals, etc.NBR Nitrile rubber
NBR acrylonitrile butadiene rubber (nitrile rubber) impresses with its exceptionally good resistance to mineral oil and fuel, as well as low compression set. NBR is therefore the perfect oil and fuel-resistant sealing material. A negative aspect of NBR rubber is its very poor resistance to ozone.Non-crosslinked foam
An uncrosslinked foam has unbranched molecular chains. This results in lower mechanical and thermal resilience. Non-crosslinked foams are mainly used for logistics packaging.NR/SBR natural/styrene-butadiene rubber
Natural/SBR rubber is particularly valued in environments where they are exposed to heavy wear due to friction or in constantly abrasive elements. The NR/SBR quality has no resistance to mineral oils and greases.
Pp
Primer
A primer with a 2-component adhesion system is used to improve the adhesion properties. The primer does not contain a cross-linking agent, so the bond to the substrate is created solely by physical forces. (adhesion)PU Polyurethane rubbers
Polyurethane rubbers are characterized by excellent wear behaviour and exceptionally high tear resistance. The high elasticity and good resistance to high-energy radiation are further positive factors. They are also resistant to oxygen, ozone, mineral oils and greases. Hydrolysis resistance to aqueous media is limited. AU polyurethane rubbers are mainly used as wipers or rollers and wheels.
Rr
REACH and foam
Vibraplast AG only processes REACH-compliant foams.Rebound elasticity
Rebound elasticity is the energy returned as a percentage and is used to assess the elasticity behavior, which indicates the extent to which the material is elastic and the extent to which it is viscous. The less deformation energy is converted into heat, the greater the elasticity. This test is particularly suitable for providing initial indications of the dynamic behavior of an elastomer by simple means. The rebound elasticity is strongly dependent on the temperature.Reflection
Reflection is the bouncing back of sound waves.Resonance
Resonance is when a vibrating system is excited at its natural frequency.Reticulate
Reticulation is a post-treatment of foams to achieve liquid, air or gas permeability. The cell membranes between the foam webs are removed, but the basic structure of the foam is retained. Only the thin intermediate skins of the foam are removed, resulting in an open-cell foam that is permeable to air or liquids.Reverberation
Reverberation is the echo that you hear after the sound excitation in rooms and musical instruments has ended.Reverberation time
Reverberation time is the reverberation of a room. The longer the reverberation time, the longer a sound event can be heard in the room and the more it reverberates.Room acoustics
One area of acoustics is room acoustics, which deals with the distribution of sound levels in rooms. Room acoustics deals with the acoustic room climate in interiors, which contributes to the improvement of speech or music intelligibility and the reduction of sound levels.Room sound attenuation
Installing sound absorbers on the interior surfaces of a room reduces sound reflection, thus shortening the reverberation time and improving the acoustics of the room.Rubber
Rubber is the non-crosslinked starting product that is used in the production of elastomers (rubber). A distinction is made between natural and synthetic rubbers.Rubber processing method
The vulcanizing tool or mould required contains one or more nests depending on the size, sensitivity and output of the rubber/metal part. The mold is first loaded with the prepared metal in the open state and then, depending on the process, with the exact volume mixture in the open or closed mold state. Possible processing methods are compression molding, transfer molding or injection molding.Rubber stress types
When designing bonded rubber springs, it is important to note that the degree of deformation varies depending on the type of load, even when the same force is applied. It is up to the designer to select the direction of force to apply to the rubber in compression, tension, shear or bending. Shear stresses produce the greatest deformations, compressive stresses the smallest. Tensile stresses should be avoided due to the non-linear spring characteristic, the tendency to flow and the poorer application of force.Rubber-metal connection
The most commonly used material for rubber-metal compounds is steel, but other metals such as zinc, aluminum, zinc and alloys can also be used.Rubber-plastic connection
Instead of metals in rubber-metal compounds, plastics can also be used. In addition to weight reduction, freedom from corrosion is a further advantage. Complex plastic parts can also be produced efficiently by injection molding. The plastics are degreased and mechanically prepared in a similar way to metal and coated with an adhesion promoter. For the production of rubber/plastic compounds, thermoplastics must be dimensionally stable at a vulcanization temperature of 160-200°C, otherwise the plastic part may deform during rubber/plastic moulding production.
Ss
Schalldämmung
Bei der Schalldämmung steht die akustische Trennung von Räumen, gegen nicht erwünschtem Schall von Nachbarräumen oder von aussen in Vordergrund. Die Ausbreitung von Luft- oder Körperschall wird beim Übergang zwischen zwei Medien durch Reflexion verhindert.Secondary path transmission
By-path transmission is the transmission of sound via adjacent walls, floors and ceilings.Shear stress
Under shear stress, the linearity limit is 35% deformation in relation to the rubber layer thickness. The shear modulus G is the only material constant of elastomers and is fixed for each compound depending on the Shore hardness.Shear stress
Under shear stress, the linearity limit is 35% deformation in relation to the rubber layer thickness. The shear modulus G is the only material constant of elastomers and is fixed for each compound depending on the Shore hardness.Shielding dimension
Reduction of the sound level of sound beams by shielding such as noise barriers or partitions is called shielding factor.Shore A hardness
Hardness is commonly expressed with the designation Shore A. The resistance to penetration by a cone is measured. Finished parts whose test surface deviates from a diameter of at least 30 mm and a test thickness of at least 6 mm are only to be regarded as comparative values for values measured under the same conditions, not as material constants.Shore hardness
The most commonly used hardness test for elastomers is the Shore hardness test according to DIN ISO 7619-1. Shore hardness is defined as the resistance of a rubber sample to penetration by a conical body of a certain size under a defined compressive force. Depending on the design of the measuring body, a distinction is made between Shore A for softer elastomer compounds and Shore D for harder elastomer compounds. In order to achieve an impeccable measurement of Shore hardness, the standard specifies a specimen thickness of 6 mm. If measurements are carried out on finished parts with a thinner wall thickness, these usually lead to incorrect results. Commercially available elastomer compounds for technical molded rubber parts are in a hardness range of 20-90 Shore A.SI/MVQ Silicone rubber
SI/MVQ is a silicone rubber which has very high heat resistance and extreme cold resistance as well as very good resistance to oxygen, ozone and UV rays.Sound
Sound is vibrations from 16 to 16,000 Hz in solid bodies (structure-borne sound) and in the air (airborne sound).Sound absorption
Sound absorption can be understood as the prevention of sound propagation through the absorption of airborne sound. The sound energy is converted into inaudible vibration waves during sound absorption and the reflection at a boundary surface is reduced accordingly. The acoustics within the room are improved and noise is reduced.Sound absorption
Sound waves never propagate without loss, but are always subject to a greater or lesser degree of attenuation - absorption. A high degree of absorption can be achieved with porous materials. Sound absorption is of great importance for the acoustic experience of the users of a room. Appropriate sound absorption allows the room to be adapted to its intended use.Sound absorption coefficient
The sound absorption coefficient α defines the ratio of absorbed to incident sound energy. Complete reflection results in α=0, while complete absorption results in α=1. Sound absorption refers to the reduction of sound energy primarily through conversion into heat. The movement of the air molecules (=sound) is converted into heat energy. (Absorbing is synonymous with “swallowing” and “soaking up”) The degree of sound absorption is frequency-dependent, which is why the measurement is carried out in the frequency range 100 to 5000 Hz.Sound attenuation
Sound absorption can be understood as the prevention of sound propagation through the absorption of airborne sound. During sound absorption, the sound energy is converted into inaudible vibration waves and thus the reflection at a boundary surface is reduced accordingly. The acoustics within the room are improved and noise is reduced.Sound bridges
Sound bridges are the most undesirable transmission paths for sound and can be largely eliminated with various noise reduction measures.Sound insulation composite systems
In order to achieve optimum results, combined materials can also be combined as composite systems for structure-borne sound insulation or airborne sound insulation. For example, multi-layer PUR foams supplemented with a viscoelastic heavy foil.Sound propagation
Sound waves propagate in a spherical shape at the speed of sound and decrease in intensity with increasing distance. This process is strongly influenced by the absorption of sound waves. A distinction is made between two borderline cases: 1. undisturbed sound propagation in a free field 2. total sound reflection. The type of sound propagation in the working area of a company will generally lie between these two idealized extreme cases. In room acoustics, the structural design of the environment or the surrounding room is described by parameters such as sound absorption coefficient, sound reduction index, insertion loss and reverberation time. These parameters are important aids in noise reduction technology.Sound reduction index
The sound reduction index R is a logarithmic value that describes the airborne sound insulation performance. The sound reduction index is given in decibels.Sound reduction index (R)
Indicates the airborne sound insulation of a building element. R = 10 log (incident sound power / transmitted sound power).Sound reflection
The reflection of a sound source from an obstacle, e.g. walls, windows, ceilings, floors, machines, etc., is an important factor in all noise problems relating to sound insulation or sound attenuation. Reflection depends on the frequency and direction of the sound wave to the obstacle as well as the nature and surface structure of the reflecting obstacle. The returning, reflected wave is superimposed with the outgoing wave and, depending on the existing conditions, in extreme cases results in a cancellation or amplification of the sound wave. In principle, it can be said that strong reflection occurs with sound-hard walls and high sound absorption can be achieved with sound-soft walls.Spring characteristic
The spring characteristic curve is the relationship between the applied force and the change in shape or displacement resulting from its effect. The spring properties depend on the elastic modulus of the elastomer and the geometric dimensions. Therefore, the binding identification of a bonded rubber spring is not the measured elastomer hardness in Shore A but the spring characteristic curve. A spring stiffness of ±12% means approx. ± 3 Shore A. For standard parts without special measures, the spring stiffness tolerance is ± 20%.Standard quality foam
The density and compression hardness describe the technical quality of a foam. The compression hardness describes the indentation behavior of foams at a defined force. The higher this value, the harder the foam feels An important quality feature of a foam is the density or volume weight (m3 kilograms per cubic meter). The rule of thumb is - 20 - 30 kg/m3 => quality for seat and back upholstery, inexpensive mattresses, - 30 - 40 kg/cbm => standard to superior quality for seat and back upholstery, mattresses, boat, camping or garden pads, etc. - 40 - 50 kg/cbm => high to very high quality and very good permanently elastic quality for a wide range of applications.Storage
Elastic mounting using vibration isolation elements for machines prevents the introduction of structure-borne noise into the building fabric. This measure minimizes the introduction of structure-borne noise at the source.Structure-borne sound
Structure-borne sound is sound that propagates in a solid body. The transmission of sound to a solid body causes it to vibrate. For example, sound propagates through thin-walled sheet metal or masonry.Structure-borne sound insulation
While the construction materials of machines and buildings such as cast iron, steel and concrete are good sound conductors and are therefore described as sound-hard in line with the material consistency, rubber, on the other hand, conducts sound poorly and is very well suited as a sound-soft material for structure-borne sound insulation. The insulating effect for structure-borne sound waves is achieved by their partial reflection at the interface of the materials and only some of them penetrate into the intermediate layer.
Tt
Thermal conductivity
The thermal conductivity is decisive for the thermal insulation properties of an insulating material. The thermal insulation property indicates the thermal energy (W) that flows through a component per meter (m) at a temperature difference of 1 Kelvin. The unit of measurement is W/mK and is abbreviated to Klein-Lambda (λ). The basic rule is that the smaller this value, the better the thermal insulation properties of the insulating material. Examples: PUR foam 0.037 / polyester fiber mats Vibra®fiber 0.037 / melamine foam Basotect® 0.033Thermoplastic elastomers
Thermoplastic elastomers (TPE) are plastics that can be compared with classic elastomers at room temperature. However, TPE plastics can be plastically deformed when heat is applied.Thermosets
Thermosets are hard and partially glass fiber-reinforced polymer materials. Once a thermoset plastic has hardened, it can no longer be reshaped. If high demands are placed on chemical resistance, heat resistance, chemical resistance and electrical insulation properties, thermoset plastic is the right material.
Uu
UL 94 fire standard
The UL 94 standard was developed to test the fire safety of plastics, in particular foams. This standard was originally used in the USA for testing plastics. However, it has since become established worldwide for classifying the flame resistance and fire safety of plastics/foams.
Vv