Process characteristics of commonly used plastics
2020-12-24 08:17:54
The process characteristics of commonly used plastics are as follows:
PE (polyethylene)
1. The shrinkage is large and it is prone to bending and deformation.
2. Cooling time is required and the forming energy rate is not good.
3. The molded product has a low depression and requires forced release.
4. The molding shrinkage rate is greatly affected by the mold temperature and the stability is poor.
5. Good fluidity and good thermal stability, but the molecular compatibility is easy to deform.
6. Lighter and softer than water.
7. Not heat resistant, and then poor printing.
8. Good resistance to chemicals, water and electrical insulation.
PC (polycarbonate)
1. The melt has a high viscosity and must be formed by high pressure and high temperature.
2. The residual stress is prone to breakage.
3. Due to the high hardness, it is easy to damage the mold.
4. There is scrap extrusion.
5. Transparent, strong, and low temperature stability.
6. Excellent weather resistance, optical rotation resistance, impact resistance, heat resistance and Creep resistance.
7. Good mechanical properties at high and low temperatures.
PP (polypropylene)
1. Poor fluidity, poor filling, flow marks, insufficient pressure, easy to dent, high pressure forming.
2. When used for optical purposes, transparency is a problem, and when dissimilar materials are mixed, attention must be paid to decomposition.
3. Excellent formability and high mechanical strength than PE.
4. Good water resistance, chemical resistance and electrical insulation.
5. It is prone to deformation, warping and depression.
6. Adhesive, the lightest plastic.
7. Low specific gravity (about 0.90), FDA grade, good transparency, non-hygroscopic, low price, heat resistance and general mechanical strength are not very high, foaming rate is not high, and printing is poor.
PVC (polyvinyl chloride [hard])
1. Poor thermal stability, the forming temperature is close to the decomposition temperature range.
2. Poor fluidity and poor appearance.
3. Will corrode the mold.
4. It is most likely to burn and produce acid gas.
5. Good strength, electrical insulation and chemical resistance.
6. Adding plasticizer will soften.
7. Poor heat resistance.
8. High specific gravity (1.4), flame resistance, good printability, different formulations with different characteristics, wide application range, low cost, high environmental impact, easy to crack when processing temperature exceeds 190 °C, and release HCI corrosive gas.
ABS (acrylonitrile-butadiene-styrene copolymer)
1. It is a kind of vinyl, which is a common material and is easy to form.
2. Good fluidity, chemical plating adhesion and heat resistance.
3. The performance of the molded product is stable.
4. The surface appearance of the gate portion and the formation of obvious fusion lines.
5. Milky white, translucent.
6. Impact resistance is better than PS.
7. ABS, mechanical strength and heat resistance of various properties can be obtained from the change of composition ratio of each polymer. It is excellent in general-purpose plastics, surface gloss, surface spray and electroplating property, hygroscopicity, yellow color. Generally, the finished product must be dyed.
AS (SAN) (acrylonitrile-styrene copolymer)
1. It is a kind of vinyl, which is a common material and is easy to form.
2. Good fluidity, good formability and good forming energy.
3. Easy to split.
4. It is prone to waste.
TPE (TPR) (thermoplastic elastomer)
1. Soft, elastic and good to the touch.
2. Easy to process, fast, and recyclable.
TPU (TPU resin)
1. Excellent mechanical properties and good elasticity.
2. Good wear resistance and chemical resistance.
3. Good compatibility with blood and cellular tissue.
4. Easy to process.
PMMA (polymethyl methacrylate [acrylic])
1. Strong toughness, colorless and transparent.
2. Excellent optical, insulating, processability and weather resistance.
POM (polyoxymethylene)
1. Commonly known as plastic steel, easy to thermal decomposition, chemical resistance and good resistance to Creep.
2. Excellent wear resistance, self-lubricity, toughness, durability, heat resistance and chemical resistance.
3. Good mechanical and impact resistance.
4. No self-extinguishing, poor acid resistance, and high mold shrinkage.
5. Similar to nylon, wear-resistant similar to PC.
6. High mechanical properties, excellent elastic recovery, poor thermal stability and high specific gravity (1.41).
PPO (polyoxyethylene diphenyl)
1. Excellent electrical properties, hot water resistance and flame resistance.
2. Poor chemical resistance and processability.
PPS (polyphenylene sulfide)
1. Good heat resistance and flame resistance, high HDT, high mechanical strength at high temperatures.
2. The crystallization rate is fast and the crystallinity is as high as 60~65%.
3. Good dimensional stability, good electrical properties, low melt viscosity and good formability.
4. Good chemical resistance and excellent chemical resistance (except concentrated nitric acid), which is equivalent to TEFLON, and no solvent can dissolve PPS at 200 °C.
5. Impact resistance, weather resistance, toughness and friction and wear characteristics are poor.
6. There will be burrs and the mechanical properties will be affected by the mold temperature.
PS (polystyrene)
1. It is a vinyl, which is a common material.
2. Good fluidity, good formability and good forming energy.
3. Easy to split and not impact (GPPS).
4. It is prone to waste.
5. Colorless, transparent, easy to dye, and good insulation.
6. Excellent water resistance and chemical resistance.
BT (BT resin)
1. Good heat resistance and board adhesion.
2. It can meet the board requirements for high speed transmission.
3. It can prevent leakage.
CA (cellulose acetate)
1. Good fluidity and good formability.
2. The surface is smooth and beautiful, with good dimensional accuracy and easy coloring.
3. Transparent, flexible and processable.
CE (cyanate resin)
1. The pure cyanate has a dielectric constant of 2.8.
2. Different kinds of reinforcing fibers can be used to make substrates with different dielectric constants. When reinforced with quartz fiber, the dielectric constant value can be as low as 3.1.
EP (epoxy resin [cold gel])
1. The metal has high adhesion and good chemical resistance.
2. High mechanical strength and good insulation.
3. The traditional epoxy resin is called a bifunctional epoxy resin. It will continue to burn after ignition, until the carbon, hydrogen and oxygen in the polymer are burned.
ETFE (ethylene-tetrafluoroethylene copolymer)
1. A type of thermoplastic fluororesin.
2. Good electrical properties: Excellent insulation with very low dielectric constant.
3. Good heat resistance.
4. Flame resistance: Oxygen Index 95%, UL94, V-0, is a flame-resistant material that can be used for different purposes.
5. Excellent chemical resistance: almost no reaction to all chemicals.
6. High mechanical strength.
7. Low friction, low non-stickiness.
8. Excellent weather resistance: direct exposure to sunlight, rain or exhaust without loss or deformation, long-term exposure to outdoor characteristics has not changed.
9. Chemical resistance.
10. When adding GF or CF, it can increase its vibration.
11. High shrinkage.
FR-PET (reinforced polyethylene terephthalate)
1. Excellent electrical characteristics, good weather resistance, excellent mechanical properties, and small creep.
2. Good heat resistance.
3. Fast crystallization, excellent formability and good fluidity.
4. Low water absorption and good dimensional stability.
5. Good surface gloss and good coloration.
6. Resistant to organic solvents, oils, and weak acids.
7. Heat resistance is better than FR-PBT.
MF (melamine silicone resin [trimeric amine silicone resin science porcelain, melamine melamine])
1. Same as UF, only the water resistance surface hardness is large.
2. Flame resistant, colorless, and easy to color.
M-PPE (modified polyoxymethylene resin)
1. Good processing stability.
2. Excellent mechanical properties.
3. Good heat resistance and water resistance.
4. Self-extinguishing.
5. Good electrical characteristics.
6. The molding shrinkage rate is small.
7. Poor chemical resistance.
LCP type I (liquid crystal polymer)
1. The highest heat resistance.
2. Good chemical resistance, dimensional stability and self-lubricating properties.
3. Deterioration occurs in bending strength and high-concentration alkali vapor.
4. The anisotropy is large, it must be formed at high temperature, and the price is high.
LCP Type II (Liquid Crystal Polymer)
1. Good chemical resistance, high fluidity, vibration absorption characteristics and mechanical strength.
2. The coefficient of longitudinal expansion is small.
3. The bending strength is poor and the anisotropy is large.
4. The strength will be affected by the thickness.
5. Unfilled grades are prone to surface peeling.
LCP type III (liquid crystal polymer)
1. Good chemical resistance, high fluidity, vibration absorption characteristics and formability.
2. The bending strength is poor and the anisotropy is large.
PA (polyamide)
1. The solution has low viscosity and good fluidity.
2. The safety of shrinkage is poor and it is easy to form waste.
3. When the melting temperature is high, the hardness is high, and there is damage to the mold, the screw, and the like.
4. Its viscosity is highly sensitive to heating temperature and is also a hygroscopic plastic.
5. It has good fluidity at high temperature, it is not easy to melt itself, and it is easy to cool and solidify after melting.
6. Strong, self-slip but wear-resistant, shock-absorbing, heat-resistant, cold-resistant, and chemical-resistant.
7. Good mechanical strength, glass fiber reinforcement effect, gas shielding and moisture absorption.
8. Insufficient strength at low temperature.
9. Large changes in size and physical properties after moisture loss.
10. Poor dimensional stability.
PAI (polyetherimide)
1. High mechanical strength and high hardness.
2. Flame retardant, UL94VO, good weather resistance.
3. Excellent chemical resistance and heat resistant water.
4. Excellent electrical characteristics, easy molding and good dimensional stability.
5. Good heat resistance and excellent creep resistance.
6. The change of the elastic modulus below 260 °C is small.
7. Poor formability, fluidity, alkali resistance and hygroscopicity.
8. The price is high.
PAR (polyarylate)
1. Excellent mechanical properties, colorless and transparent (unfilled).
2. Temperature resistance and HDT are above 150 °C, low temperature and impact resistance.
3. Not easy to burn, oxygen index 36.8, UL94VO.
4. Excellent weather resistance, UV resistance and electrical properties.
5. The impact strength is large and the thickness dependence is small.
6. High temperature potential is good.
7. Solvent resistance, acid and alkali resistance and poor fluidity.
PBT (polybutylene terephthalate)
1. Good moldability, weather resistance, heat resistance, heat aging, electrical properties, fatigue resistance, abrasion resistance, hot water resistance and chemical resistance.
2. It is a saturated polyester with PET. It has high meltability, rapid crystallinity and fast curing speed.
3. Poor impact strength.
PCTFE (polychlorotrifluoroethylene)
1. The viscosity of the melt is extremely high and must be formed by high pressure.
2. It is prone to discoloration.
PDAP or DAP (poly(o-butylene terephthalate))
1. High strength, good insulation, chemical resistance and heat resistance.
2. Good dimensional stability and good wear resistance when wet.
3. Can be formed at low pressure.
PEEK (poly(phenylene ether ether ketone)]
1. High temperature resistance, good thermal stability, super high heat resistance (excellent to PPS), HDT above 315 °C, and UL continuous use temperature of 250 °C.
2. High mechanical strength such as impact resistance, wear resistance, creep resistance and fatigue resistance.
3. Chemical resistance (except concentrated sulfuric acid) and hot water resistance (PPS, PES or higher).
4. It is resistant to gamma rays, flame retardant and extrusion processability.
5. Excellent electrical properties under high temperature and high humidity.
6. The minimum amount of smoke and radiation resistance.
7. The price is high, it must be formed at high temperature, and the fluidity is poor.
8. Good toughness, strength and rigidity.
9. Good flame resistance, no need to add flame retardant.
10. Poor processing.
PEI (polyamide imide)
1. Used in injection molding, the highest tensile strength.
2. The best resistance to latent denaturation (normal temperature ~ 150 ° C).
3. Flame retardant, UL94VO, oxygen consumption index of 42.
4. Good wear resistance, temperature resistance, oil resistance and chemical resistance.
5. Good flame resistance and weather resistance, low smoke generation and good transparency (unfilled).
6. The change of the elastic modulus below 150 °C is small.
7. Must be formed at high temperature, with poor fluidity, alkali resistance and hygroscopicity.
PES/PESF (polyether)
1. -100~170°C, excellent mechanical strength and temperature resistance.
2. Good dimensional stability and good transparency (not filled).
3. High temperature resistant steam and hot water and acid and alkali.
4. High oxygen consumption index (UL94V0), flame retardant.
5. Excellent electrical characteristics.
6. Less smoke.
7. Excellent high temperature potential.
8. Below 180 °C, the elastic modulus changes little.
9. Poor solvent resistance and weather resistance, high temperature molding.
PF (phenolic resin [bakelite])
1. High mechanical strength, insulation, combustion resistance, water resistance, acid resistance, oil resistance and stability.
2. Dark color is not alkali resistant, easy to change color, and has limited dyeing.
PFA (tetrafluoroethylene copolymer)
1. A type of thermoplastic fluororesin.
2. Good electrical properties: Excellent insulating material with very low dielectric constant and very low dielectric dissipation factor.
3. Heat resistance: Wide temperature range (-200 ° C to +280 ° C).
4. Flame resistance: Oxygen Index 95%, is a flame-resistant material that can be used for different purposes.
5. Excellent chemical resistance: almost no reaction to all chemicals.
6. High mechanical strength.
7. Low surface energy: low friction, low non-stickiness, and high water repellency and oil repellency on the surface of water and oil, which can increase the reliability of raw materials.
8. Excellent weather resistance: direct exposure to sunlight, rain or exhaust without loss or deformation, long-term exposure to outdoor characteristics has not changed.
9. Good chemical resistance, low friction coefficient and non-adhesiveness.
10. Poor formability, high shrinkage and high price.
PI (polyimide)
1. The highest heat resistance.
2. Excellent wear resistance, creep resistance and radioactivity.
3. Excellent chemical resistance and strong acid resistance.
4. It is difficult to shoot and eject.
5. The change in the spring constant at 240 ° C is small.
6. Good chemical resistance (except concentrated nitric acid).
7. Poor moldability and moisture absorption.
8. The crystallization temperature is high.
9. The dimensional change is very small, and the thermal expansion in the X and Y directions is small, which can prevent the adhesion of the copper foil from being deteriorated due to heat, and the thermal expansion in the Z direction is small, and the hole of the multilayer board can be avoided. The wall copper layer is thermally fractured.
PSF (polysulfone)
1. The mechanical strength is high at -100 ° C ~ 150 ° C, and the electrical characteristics remain stable.
2. Temperature resistance, UL746, HDT are above 150 °C.
3. Good chemical resistance, hot water and water vapor are the most prominent, and can maintain excellent electrical properties under temperature changes.
4. It can resist the deterioration of oxygen and ozone at high temperature.
5. Non-toxic, FDA and hygienic specifications are acceptable, amber transparent.
6. Good acid and alkali resistance, good transparency when not filled.
7. Poor solvent resistance, release property and fluidity.
PTFE (polytetrafluoroethylene)
1. High and low temperature electrical insulation is good.
2. The chemical resistance is extremely strong.
3. Good heat resistance, wear resistance and stability.
PU or PUR (polyurethane)
1. Flexible and strong.
2. Good wear resistance, heat resistance, oil resistance and aging resistance.
3. Slightly resistant to acids, alkalis and hot water.
PVA (polyvinyl alcohol)
1. Colorless transparent elastomer.
2. Good heat resistance.
3. The insulation softening point is high.
PVAC (polyvinyl acetate)
1. Colorless and transparent.
2. Adequate and excellent resistance to light.
3. Poor heat resistance.
4. High water absorption and most solvents are soluble.
PVDC (polyethylene formaldehyde)
1. Larger than PVC resistant.
2. Good heat resistance.
3. The film has low gas permeability.
UF (urinary aldehyde resin [electric jade])
1. Colorless, coloring free.
2. Similar to PF, it is slightly inferior, water resistance and weather resistance are not good.
UP (unsaturated polyester [cold gel])
1. Excellent insulation.
2. The fiberglass reinforcement UP has high mechanical strength.
3. Heat-resistant, chemical-resistant, low-pressure forming, water resistant.
SP or SI (silicone plastic [or silicone resin])
1. High temperature resistance and good insulation.
2. Unique surface physical properties, mold release, defoaming and abrasion resistance.
3. It is resistant to sunlight, chemicals and non-toxic.
A captive bolt pistol (also variously known as a cattle gun, stunbolt gun, bolt gun, or stunner) is a device used for stunning animals prior to slaughter.
The principle behind captive bolt stunning is a forceful strike on the forehead using a bolt to induce unconsciousness. The bolt may or may not destroy part of the brain.
The bolt consists of a heavy rod made of non-rusting alloys, such as stainless steel. It is held in position inside the barrel of the stunner by means of rubber washers. The bolt is usually not visible in a stunner in good condition. The bolt is actuated by a trigger pull and is propelled forward by compressed air or by the discharge of a blank round ignited by a firing pin. After striking a shallow but forceful blow on the forehead of the animal, spring tension causes the bolt to recoil back into the barrel.
The captive bolt pistols are of three types: penetrating, non-penetrating, and free bolt. The use of penetrating captive bolts has, largely, been discontinued in commercial situations in order to minimize the risk of transmission of disease.
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