Physical and Mechanical Properties

PA before stretching	PA after stretching

PA is characterized by very high service life and resistance to aging. Glass fibre reinforced PA displays a higher E-module and a higher toughness. The abrasion behavior is good. If used with bearings, an additive of MoS2 or PTFE/Silicone gives excellent slip and minimal lubrication qualities.

Polyamide is suitable for sawing, boring, turning, grinding, polishing, welding (see below), lacquering and printing.

Important note

If parts made from PA have not been stored in the original packaging but at a dry and warm place, then they should be kept in warm water for 24-48 hours before assembly. PA parts shouldn't be assembled in frozen condition (i.e. after transport or stocking). Minimum core temperature of articles for assembly is > 4 °C (depending on environment temperature 24-48 h in closed original packaging are needed for rewarming).

Optical and Chemical Properties

PA can be disposed by its polar amide groups in its polymer chains upon others into following basic grades: 4.6, 6, 6.6, 6.10, 11, 12.

Depending on the type of PA the basic tint is yellow-white, water-white or light-white and is all-round dye able. PA goes yellow with age and if it is exposed to UV-rays. Thus the colour is not consistent over a long period if used in parts in its natural colour.

Given increased crystalline properties PA displays good resistance to aliphatic and aromatic hydrocarbons, oil, lubricants, grease, some types of alcohol, ester, ketones, ether, organic and inorganic bases up to a medium concentration, chlorated hydrocarbons such as carbon tetrachloride, Freon, paints and varnishes. Chloroform and methyl chloride produce very strong swelling. Alcohols such as methanol and ethanol have a similar effect as water or salt-water (light swelling, low reduced mechanical strength). PA is not resistant to solutions of oxidisation media, mineral acids and formic acid, strong lyes, phenols, cresols and glycols.

Resistance to Weather and Ageing

PA is adequately resistant to ageing and weather conditions. For external use the level of resistance can be increased by using a correct colouration , e.g. soot. In the case of glass fibre reinforcing polyamide the surface enlargement of parts produced by the glass fibre means that surface of parts is more stressed. The mechanical properties are not influenced to any great extent. Addition of suitable UV stabilisers (HALS) prolongates outdoor usage of PA moulded parts in any colours up to 10-20 years.

Special Uses - Product Ranges

Glass fibre and other fillers which increase strength, MoS2 and PTFE/Silicone designed to improve slide qualities, various stabilisers, materials with good conductivity or the improvement of the electrical conductivity - fibers, textiles, tubes, screws, nuts, shims, cogs, door and furniture fittings, slide bearings, sliding elements, bearing sleeves, fan wheels, pump casings, filter pads.

Thermic Properties

Physiological Behaviour and Joint

It is not advisable to bring PA into contact with foodstuff, which contain water if these are subject to heat for a longer period of time. Dry, non-reinforced injection-moulded parts made of PA can be welded via ultrasonic welding, friction- or vibration welding and hot element welding to give sound, tough joints. Dampness and glass fibre reduce the weld ability. For purposes of adhesion, solvents and varnishes based on phenol or resorcinol, concentrated formic acid, impact adhesives and cyanate glues are particularly suited for PA.

Physical and Mechanical Properties

With 0,90-0,91 g/ccm PP is a very light, partially crystalline thermoplastic material belonging to the class of polyolefins. PP has a good stress crack resistance, a good toughness and an excellent permanent fatigue strength in suitable thin wall thicknesses. As opposed to homopolymeric PP copolymeric PP displays a very good notched impact behaviour and therefore it is suitable for some technical purposes. The service life decreases as temperature increases. PP is water repellent (hydrophobic) like the most polyolefins. As regards hardness and strength partially crystalline PP is at the upper limits of partially crystalline HD-PE and bridges the gap to partly crystalline PA 6. With novel catalysts properties (metallocene and other) will be reached covering the whole range of the harder thermoplastic polyolefin-based elastomers (TPE), as far as long way into Nylon 6 range.

Optical and Chemical Properties

In its natural colour PP is transparent, but not glassy. As the wall thickness of parts reduces, PP moulded parts become increasingly transparent. Random-Copolymers are nearly glassy moulded in thin-walled parts. PP moulded parts are non-polar and therefore can only be attacked by very few chemicals. It is resistant to water (repellent, too), salt solutions, acids and alkalis. It is resistant to alcohol solutions up to 60°C and to solutions of washing lyes. It swells up when it is exposed to halogenated hydrocarbons and at increased temperatures by grease, oil and wax. Given suitable colouration on a polyurethane or acrylic base PP can be varnished. 

Resistance to Weather and Ageing

In the visible range PP is adequately resistant to radiation. UV rays produce oxidation of the PP parts surface and lead therefore to brittleness and eventually to disintegration. A suitable colouration, e.g. soot, acts as a stabiliser, but reduces the resistance to ageing through heat. Addition of suitable UV stabilisers (HALS) prolongates outdoor usage of PP moulded parts in any colours up to 10-20 years.

Special Uses - Product Ranges

Glass fibre and other fillers designed to strengthen the material, various stabilisers, conductive materials for improving electrical conductivity, addition of PP-based thermoplastic elastomers (TPO) for softer and toughening setting - Storage and transport containers, covers, fan wheels, furniture fittings, housings for electrical appliances.

Thermic Properties

The temperature range for permanent use of mechanical unloaded and non-reinforced PP parts reaches from -40 to 110°C. For a short time same PP parts can also withstand temperatures of about 140°C. It starts to burn with a very light smell of wax at about 330°C. It burns with a weak flame and produces burning drops.

Physiological and Joint Behaviour

PP tastes and smells neutral and can be exposed to the skin unless additives are used which are harmful to health. Some producers attest compatibility to foodstuff for their PP. Thanks to its good chemical consistency because of the non-polar parts surface only impact glues can be used. The surface of parts must be scuffed or based-coated first. Same effect has flaming and corona discharge. PP can be jointed via heat element, friction-, vibration- or hot gas welding. 
 

Physical and Mechanical Properties

With 0,90-0,96 g/cm³ PE is a very light, partially crystalline thermoplastic material belonging to the class of polyolefins. VLD= Very Low Density ~0,90 g/cm³ and HD= High Density ~0,96 g/cm³ limit the range of density. PE in its normal condition is water repellent (hydrophobic) like the most Polyolefin’s. PE is very tough. The E-module, the tensile strength and the surface hardness have low values, growing up from VLD-PE to HD-PE. Good resistance to expansion cracks is principally given in the case of VLD-PE and LLD/MLD-PE. With increasing density, increasing melting index and increasing wall thickness PE becomes more sensitive to expansion cracks. If parts made of HD-PE (choice due to hardness and strength) are be exposed so wall thickness, melting index and density must bei optimal low.

Optical and Chemical Properties

In its natural colour PE is translucent. With reducing wall thickness of parts, PE moulded parts become increasingly transparent. Given correspondingly-designed injection moulding tools VLD/LLD-PE parts demonstrate a very shiny surface. Natural coloured PE parts are UV-sensitive and go yellow with time. - PE moulded parts have a non-polar surface and can therefore only be attacked by very few chemicals. PE is resistant to acids, lyes, alcohol, oil, and salt solutions. HD-PE is also resistant to benzin. VLD-PE and LD-PE swell in aliphatic and aromatic hydrocarbons. PE is not resistant to very strong oxidation media, e.g. nitric acid. The steam permeability level is small; gas permeability level is quite high in comparison to other plastics.

Resistance to Weather and Ageing

In the visible range PE is adequately resistant to radiation. UV rays produce oxidation of the PE parts surface and lead therefore to brittleness and to disintegration over time. A suitable colouration, e.g. soot, acts as a stabiliser, but reduces the resistance to ageing through heat. Addition of suitable UV stabilisers (HALS) prolongates outdoor usage of PE moulded parts in any colours up to some years.

Special Uses - Product Ranges

Fillers for more cheapening of material, various stabilisers, addition of PE-based thermoplastic elastomers (TPO) for softer and toughening setting - Transport containers, shims, pipe plugs, furniture fittings, one-way parts, substitution of soft PVC by VLD-PE for highly elastic parts.

Thermic Properties

The temperature range for permanent use of mechanical unloaded parts are, in the case of VLD-PE -50 to 80°C, in the case of LD-PE -50 to 95°C and in the case of HD-PE -50 to 105°C. PE lits at about 340°C. PE burns also outside the flame with a significant smell of wax weakly glowing and then drips down burning.

Physiological and Joint Behaviour

PE is physiological harmless as far as additives are used which are harmful to health. Some producers attest compatibility to foodstuff for their PE. Thanks to its good chemical consistency because of the non-polar parts surface only impact glues can be used. The surface of parts must be scuffed very accurately and based-coated first. Same effect has flaming and corona discharge. Better is to avoid gluing and varnishing PE moulded parts. PE can be jointed via heat element, friction-, vibration- or hot gas welding.
 

Physical and Mechanical Properties

With 1,14-1,56 g/cm³ PVC-soft is a relative heavy (caused of its halogen component [Cl]), amorphous thermoplastic material. Depending on used plasticizers there are soft rubber type mixtures of 40 Shore A (Shore A = unit hardness for soft plastic) to hard rubber mixtures of 98 Shore A. The latter can be placed approximately at the crossover range between LD- to HD-PE. In comparison to soft rubber the oscillation resistance and tendency of creep properties are greater. The high attenuation and the concomitant resilience are suitable for absorbing bumps and vibrations. PVC only absorbs water to a slight extent. Soft PVC is very tough and has a very high stress fracture resistance.

Optical and Chemical Properties

As regards the chemical resistance of soft PVC as against not soft set PVC (PVC= hard PVC) you have to make allowances depending on the type and percentage of the plasticiser(s). While assembly or application moulded parts of soft PVC can only be exposed to such varnished or coated components which don't cause any migration of the plasticiser. Same for present of solvents of the plasticiser. Raw PVC is resistant to benzin, oil, thinned lyes and acids as well as salt solvents of all kinds. PVC is not resistant to organic solvents such as alcohol, ether, ester, ketone, aromatic hydrocarbons, chlorinated hydrocarbons, strong lyes and acids. Moulded parts from natural coloured soft PVC are glassy-transparent made up. The material goes with production a little bit yellow, which is made up a little bit blue. This can be visible at the smaller sides of moulded parts depending on the light refraction. Given correspondingly-designed injection moulding tools soft PVC parts have a very good glossy surface.

Resistance to Weather and Ageing

The resistance of soft PVC to light, weather and ageing is well and can be advanced by suitable colouration. Soot based black colouring results in an excellent UV resistance and reducing of warmness ageing resistance.

Special Uses - Product Ranges

Conductive fillers for discharging power, various additives and stabilisers - Cable grommets, small elastic feet, suction pads, door bumpers, ferrules, plugs, shock damping elements, glass panel bumpers, adhering elements.

Thermic Properties

Without any mechanical load the permanent operating temperature range is about -25 to max. 80°C depending on the wall thickness of moulded parts and percentage of the plasticiser(s). Harder settings drift the range to higher temperatures. Raw PVC is flame-retardant because of its halogen component (Cl). Percentage and type of plasticiser(s) characterise the burning behaviour and demerged substances.

Physiological and Joint Behaviour

Soft PVC contains plasticisers which can migrate depending on exposed substances. Given contact with foodstuffs specials plasticisers must be used. Soft PVC can be glued together with Polycarbonate (PC)- and THF-based solvent glue, Polyurethane (PUR)- and Polyester dual-component glue, polychlorinated Butadiene and with vinyl polymers.

ABS (1,04-1,05 g/cm³)  is a relative light, amorphous technical thermoplastic. It is relative hard and stiff and has good impact resistance, better than allied impact resistant Polystyrene (SB). ABS features high resistance to changing temperatures and low water absorption (low hygroscopic). It is low weathering resistant. ABS will be often selected for glossy cases, multi-component-moulding parts, chrome-plated parts and for laser-labelled parts. Natural colour is beige up to yellow-brown and with special types transparent colour is possible. ABS will be processed at 240-260 °C and inflames at 400 °C with glaring and sooting flame with sweetish smell.

Additives are substances, which are added to a pure plastic for enlarging and optimising its properties and to optimise its costs to use relationship.  As a rule each plastic on the market offered for processors contains already several additives. Aside there are additives, which processors can add by themselves or versed compounding plants can incorporate into their compounds. Additives are dived by function into following groups in essence:

Compounds are process-ready material recipes as granules or powder. Ingredients are one or more plastics and depending on tasks additives, colours, fillers and reinforcements. As a rule compounds for thermoplastics and elastoplastic thermoplastics will be produced on fitted compounding extruders with following granulators or pelletizers. This is a very material-gentle production which leads to very homogenous compounds. High-filled high-viscose compounds e.g. for production of ceramic or metal powder preforms, in which plastics are only binder, will be produced in kneader mixers.

Colourings of plastics take place with organic or inorganic colours or effect pigments, which are mixed into plastics whilst processing or compounding with as a rule 0,5-5% in form of colour powder, liquid colour (with liquid carrier), paste colour (with paste carrier) or colour master batch (pressed colour granule or colour granules with low, neutral effective plastic carrier). On high requirements for colour adaptions of item list parts of different materials (plastic, metals, wood) as a rule compounders or colouring manufacturers have to take on responsibility. Calling for compounders or  colouring manufacturers involves mostly a significant price increase for the item list parts. The technical adpation of colourings of different item list parts will be as a rule avoided by choosing different colours.

Fillers are as a rule budget-priced cost-reducing substances, which don't match with their part or only in controlled way (wood flour and more).

Reinforcements give loaded plastic parts or half-finished products a better stiffness, higher mechanical strength and higher heat resistance. To be used are embedded reinforcements in the form from fibres, textures, bowls and graining consisting of glass, carbon, plastic and minerals (light materials near the weight of plastic), which partly equipped with coupling agents and directional embedding enable further enlargement of strength. Also are self-reinforcements possible by stretching of fibres like those of Nylon and Polyethylene.
 

Thermoplastics are divided in amorphous and partially crystalline types, whereas amorphous structures in a rule are clear-transparent and partially crystalline structures are translucent up to a shielding colour.

amorphous

partially crystalline

As a rule blends are special mixtures of two thermoplastics. Possible is that only by chemical adapting, because thermoplastics are incompatible among each other (distortion, decomposition, delaminating) or they are only adhered among each other by coating of one thermoplastic on another in the injection mould. Well known blends are PA+ABS, PC+ABS, PC+PET, PC+PBT.

Macromolecules contain a great number of atoms, which are chemical bond by primary valences and will be differentiated by Staudinger in linear molecules and ball molecules or in case of plastics depending on their degree of polymerization (Hemicolloids - degree of polymerization 10 up to 100, Mesocolloids - degree of polymerization 100 up to 500 und Eucolloids - degree of polymerization > 500).

Monomers are single molecules of plastics and possess at least one functional group (reaction- or bonding group as condition for the bonding in polymers).

Polymers or plastics are differentiated in heteropolymers (bonding of equal monomers) and copolymers (bonding of monomers with differing monomers, groups or atoms) and are produced by polymerization, polyaddition or polycondensation (type is plastic-specific) and contain, depending on degree of polymerization, an equivalent number of in primary valences bond monomers.  Plastics are differentiated classified by their primary chains into molecular closely or widely spread and by their molecular weight between low- and ultra high molecular.

PC (1,2 g/cm³)  is a middle-weight, amorphous technical thermoplastic. It is very hard and has an excellent fracture toughness. PC features high heat deflection temperature, low temperature dependence and low water absorption (low hygroscopic). PC will be mostly selected for indoor parts as high transparent cases and covers, for high fracture-tough components, so as for optical parts (CD’s, DVD’s, lamp components, lenses). Natural colour is highly clear-transparent. PC will be processed at 320-350 °C and burns in the flame and goes out outside.

POM (1,42 g/cm³)  is a relative heavy, partially crystalline technical thermoplastic with structure -(CH2-O-)n for homopolymers. POM features in the range of not reinforced thermoplastics with very high strength and stiffness (also at long-term stress and at low temperatures) beside high dimensionally stability and excellent fatigue strength. Wear resistance is nearly as well as at PA. POM will preferred selected for technical applications like snap-in joints, slide bearings (also with Silicon- or PTFE-additives), rolls and gear tooth components. Natural colour is whitely-opaque. POM will be processed at 180-190 °C, inflame itself at 375 °C and burns at 323 °C with a light bluely flame with penetrative Formaldehyde smell.

PTFE (2,16 g/cm³) is a very heavy, partially crystalline technical thermoplastic with a Shore D hardness of 55-60. Its structure is CnF2n and it belongs to the class of polyhalogenolefines. Indeed PTFE is a thermoplastic material, but with near melting and disintegration temperature. Due to this PTFE can be as a rule only processed by sintering or pressure sintering and degrees of freedom for design are limited to simple designs. It was detected in 1938 by Roy Plunkett and was applied for a patent in1941 by Dupont. PTFE bends to creep under pressure and has to be stabilized by addition of glass fibers or other strength increasing additives. PTFE is very less reactive. Self aggressive acids like aqua regia cannot attack PTFE. PTFE has one of the lowest coefficients of friction of solid materials. PTFE slips on PTFE like wet ice on wet ice. Also sticking friction is equal to sliding friction so that the transition from standstill to movement acts without the stick-slip-effect. One impressive practise example for that was the movement of the new 12,500 tons heavy Oberkassel Bridge in Düsseldorf/Germany for 47,5m on PTFE slide bearings on April 7th and 8th 1976. It exist nearly no material with adhere to PTFE, due to the extremely low surface tension. PTFE is supremely resistant to all acids and lyes, alcoholes, ketones, oils, etc. and is not resistant to sodium. Furthermore PTFE is resistant to frost down to −200 °C; only glue able after pretreatment; physiological harmless; not combustible. Its natural colour is due to standard types covering white. The working temperature reaches up to 260 °C. PTFE melts at 327 °C and disintegrates above into high aggressive hydrogen fluoride acid and high toxic pyrolysis products.

Since a few years PTFE is being used for the range of furniture glides. There a unique composit of rubber and PTFE can be named, which delivers an excellent silencer and an optimal floor protection so as minimal values for sticking and sliding friction while moving furniture. This type as a rule is a 2-3 mm flat and one side spherical rubber circular blank (square and rectangular, too) on which is applied a more 1/10 mm strong foil of PTFE under high pressure and temperature. These universal slide inserts can bei equipped with a nail for wooden chair legs or other wooden furniture, can be glued on or can be inserted in furniture glides. Please look at our WebShop range under the category "Glides (furniture, framework)" for article series UG/RE, UG/RU, UGN/RU, GLUG, GGUG2000 and KKSGUG UG/RE, UG/RU, UGN/RU, GLUG, GGUG2000 and KKSGUG. PTFE slide inserts are useful for easy moving of furniture on the most floors. PTFE slide inserts makes moving of furniture on textile floors much easier. For seating furniture on smooth floors PTFE is not suitable, because seating furniture move unintended.

PU is a very multi-purpose plastic material. Depending on recipe and production process PU is available as thermoplastic (thermoplastic elastomer), elastomer or thermoset. PU products we see in all ranges of our everydays life (matresses, soles of shoes, tires of wheels and castors, insulating materials, noise insulation elements, resin laquer, glues, insulating foams and a lot more).

SB (1,04-1,05 g/cm³)  is a relative light, amorphous thermoplastic. It is relative hard and stiff and has good impact resistance, better than Polystyrene (PS). It is not weathering resistant. SB will be mostly selected (also foamed --> SFM) for budget-priced indoor cases and case components. Natural colour is strong shielding whitely-opaque. SB will be processed at 180-280 °C, is easy inflaming, burns with glaring and strong sooting flame with sweetish smell and light smelling to burned rubber.

Nitrile rubber is a synthetic rubber. The acronym is derived from NBR Nitrile Butadiene Rubber (nitrile-butadiene rubber). Nitrile rubber is obtained by copolymerization of acrylonitrile (ACN) and 1,3-butadiene. The products manufactured from nitrile rubber vulcanizates have good resistance to oils, greases and hydrocarbons, good aging characteristics and low abrasion. Depending on the mix-up the thermal scope is between -30 ° C to +100 ° C, briefly up to 130 ° C; at higher temperatures the material hardens. Depending on the article, the material has a hardness between 60 and 80 Shore.

The array of side chains at main chains of macromolecules decides essential the properties of plastics (amorphous or partially crystalline and with that clear-transparency or translucent up to shielding natural colour, the chemical resistance, the mechanical properties and so on). Following three types will be differed: atactic, isotactic and syndiotactic:

atactic - side chains in unbalanced array at main chain

isotactic - side chains in regular one-sided array at main chain

syndiotactic - side chains in regular alternating array at main chain

Is a collective term for thermoplastics with properties like real elastomers (with cross linked molecule chains: synthetic rubber). These are classified depending on their allied thermoplastics in:

These are different to plastomers (with weight 0,9 g/cm³ very light thermoplastics with very short molecule chains - e.g. Polyolefinplastomers [POP's]).

are hard or even brittle at room temperature. By warming in certain temperature ranges they soften and plasticise, because the not fixed unmashed molecule chains begin to move against each other. With more warming molecule chains begin to "flow" and the thermoplastic melts. Thermoplastics begin gradually to decompose above the melting temperature. In the presence of Oxygen or open fire the thermoplastic burns with open flame or by charing. 

Thermoplastics are in quantity the largest group under he sythetic polymers (= plastics). As examples are mentioned the four most important: Polyethylene, Polypropylene, Polystyrene and Polyvinylchloride. This four mass plastics take two third of the whole plastic production. They ambient us daily in form of wrapping, device housings and in a large range of articles of daily use.

Under collective term thermosetting plastics (before processing one- or multicomponent resins or powders) are collected hard, not again thermal plasticisable plastics with with 3-dimensional close-mashed cross-linked molecule chains, which are primarily the following:

Epoxy resin (EP)
Urea-Formaldehyde resin (UF)
Melamine-Formaldehyde resin (MF)
Acrylic resin (MMA)
Phenol-Formaldehyde resin (PF)
Polyester resin (unsaturated Polyester = UP)

Cross-linked thermoplastics (by radiation and/or addition of cross-linking agents - for example cross-linked PE [VPE or PE-X] for water tubes and for films for enhancement of mechanical properties, chemical resistance and continuous operating temperature).

Diverse thermosetting plastic formulations will be standardised encountered under the term cured resin (e.g. “form stuff” FS31).

Under collective term elastomers are soft-elastic, not again thermal plasticisable plastics with 3-dimensional wide-mashed cross-linked molecule chains collected, which are primarily the following:

Acrylic Ester rubber (ACM, ANM, AR)
Brominated Butyl rubber (BIIR)
Butyl rubber (GR-I, IIR)
Chlorinated Butyl rubber (CIIR)
Chlorosulphonated Polyethylene (CSM)
Epichlorhydrin rubber (CO, CHR, ECO, ETER)
Ethylene-Propylene-Terpolymers (EPDM)
Ethylene-VAC-Copolymers (EVA, E/VA)
Fluorine rubber (FPM, CFM, MFQ)
Nitrile rubber (GR-N, NBR)
Polybutadiene (BR)
Polychloroprene, Chloroprene rubber (CR)
Polyisoprene, natural rubber (NK, NR)
Polysulphide rubber (SR)
Silicone rubber (SI)
Styrene-Butadiene rubber (GR-S, SBR)
Urethane rubber (AU, EU)

Rubber in liquid form is characterized with a "L" in the front of material short cut (e.g. LBR). Mixtures of defined rubbers in defined mixture relations under addition of homogenizers or compatibilizers are limited and partly with extensive complexity possible and are offered mostly by raw material producers of the chemical industry or chemical specialists.

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