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Cosmetics packaging hose plastic PET injection and blowing tube billet process points
by：Lisson
2020-11-16
Article reading PET is Polyethylene
terephthalate PET, application in the field of beverage packaging promotes the rapid development of beverage packaging industry. At the same time, the development of the beverage packaging industry also provides development space for the application of PET. Strictly control the PET injection preform and blow hose technology is the key to ensure the appearance of the PET hose and its economy.
plastic explanation PET billet injection and blowing hose process points
PET is Polyethylene
terephthalate PET, application in the field of beverage packaging promotes the rapid development of beverage packaging industry. At the same time, the development of the beverage packaging industry also provides development space for the application of PET. Strictly control the PET injection preform and blow hose technology is the key to ensure the appearance of the PET hose and its economy.
the characteristics of PET
PET is the product of ethylene glycol and terephthalic acid condensation is saturated thermoplastic polymer. PET molecule has a linear and half a crystalline state. The most simple, the process of production of PET is terephthalic acid with ethylene glycol reaction monomer ( The esterification) , and then condensed growth chain polymer PET polymerization degree changes with temperature and pressure. PET, like a lot of plastic, there are three states in the manufacturing process of change, namely the glassy state, high elastic state, viscous flow state. Which involves three temperature shift: the crystallization temperature of glass transition temperature Tg, Tc, melting point, Tf.
from the amorphous glassy state to the rubbery state change of glass transition, which represents the long chain segment began to exercise. External heating can add molecules ( Link) Degrees of freedom in the glassy state solidification molecules can move now. Glassy state transition depends on the morphology of PET. When the characteristic viscosity ( IV） High crystallization is obvious, the molecular chain of degrees of freedom is restricted, at the same time,
high Tg. As the temperature rises gradually produce local spherulite, lead to local chain because of intermolecular forces and rearrangement, namely the crystallization. For PET, maximum crystallinity of about 55%, the limit is caused by aromatic ring rearrangement is slow, so that the aromatic ring of the obstruction of crystal formation. If T < c, PET viscosity retards segment to orderly movement ( No crystallization) ； T > Tc, prevent heat action of amorphous zones ( Tendency of crystal) 。 Melting point temperature of Tf all crystal disintegration.
PET dryer and dryer
hydrolysis
solid PET easy absorption of moisture from the air. Storage, the PET will hygroscopic until saturated and environmental conditions. Saturation value up to 0. A 6% weight. Usually, when the PET shipments from other suppliers, the moisture content lower than 0. A 1% weight. In order to get the best product performance, it is necessary to reduce the moisture content to zero. 004%, the best is 30 PPM before melting.
if the resin containing water, even if low will cause a series of reactions: when the temperature is higher than PET melting point ( About 250 ℃) , the water can quickly cause polymer degradation ( Due to the degradation of water chemical chain cut off) Because it will reduce the molecular weight, lower apparent viscosity and related physical properties. In fact, hydrolysis under low temperature ( Such as 150 ℃) Begin to happen, but the speed is low, its speed increased with temperature increase. Under the condition of drying and molding, IV reduction cannot be greater than zero. 02dl/g。 Reduced viscosity is too big, can lead to crystallization rate increases, adverse to the transparency of the tube billet, and resulting in a decline in the mechanical properties of the soft tube, bearing strength and impact strength decreased.
thermal degradation
the influence of temperature on the dry PET is very complex, it not only affects the rate of diffusion of water vapour, also has influence to the dry chemical process, so eventually will affect the performance of the resin. Considering potential hydrolysis and thermal process is very necessary, as mentioned above, with the
IV drop, hydrolysis accelerated at above 150 ℃, because hot transformation process is faster than diffusion process, premature drying temperature increase is unfavorable. Also, even if most of the water vapor can be siphoned off, but too high temperature ( Such as higher than 180 ℃) Will lead to the thermal degradation and thermal oxidation ( In the dry air system) So that the polymer chain rupture, also release the byproduct material, resulting in a decline in physical properties. A by-product of AA composition, physical properties of change will be expressed in the tube billet, such as
mist crystallization, IV drop, yellow, etc.
PET dryer drying principle and basic performance in desiccant bed dryer, the air is absorbed moisture first desiccant moisture absorption, a hot air blower to dry hot air pressure into the bucket. Return air through the desiccant drying cycle again, after being heated, desiccant release moisture, after cooling and absorbs moisture. So, must minimize the gas path of the two separated, desiccant and exist.
terephthalate PET, application in the field of beverage packaging promotes the rapid development of beverage packaging industry. At the same time, the development of the beverage packaging industry also provides development space for the application of PET. Strictly control the PET injection preform and blow hose technology is the key to ensure the appearance of the PET hose and its economy.
plastic explanation PET billet injection and blowing hose process points
PET is Polyethylene
terephthalate PET, application in the field of beverage packaging promotes the rapid development of beverage packaging industry. At the same time, the development of the beverage packaging industry also provides development space for the application of PET. Strictly control the PET injection preform and blow hose technology is the key to ensure the appearance of the PET hose and its economy.
the characteristics of PET
PET is the product of ethylene glycol and terephthalic acid condensation is saturated thermoplastic polymer. PET molecule has a linear and half a crystalline state. The most simple, the process of production of PET is terephthalic acid with ethylene glycol reaction monomer ( The esterification) , and then condensed growth chain polymer PET polymerization degree changes with temperature and pressure. PET, like a lot of plastic, there are three states in the manufacturing process of change, namely the glassy state, high elastic state, viscous flow state. Which involves three temperature shift: the crystallization temperature of glass transition temperature Tg, Tc, melting point, Tf.
from the amorphous glassy state to the rubbery state change of glass transition, which represents the long chain segment began to exercise. External heating can add molecules ( Link) Degrees of freedom in the glassy state solidification molecules can move now. Glassy state transition depends on the morphology of PET. When the characteristic viscosity ( IV） High crystallization is obvious, the molecular chain of degrees of freedom is restricted, at the same time,
high Tg. As the temperature rises gradually produce local spherulite, lead to local chain because of intermolecular forces and rearrangement, namely the crystallization. For PET, maximum crystallinity of about 55%, the limit is caused by aromatic ring rearrangement is slow, so that the aromatic ring of the obstruction of crystal formation. If T < c, PET viscosity retards segment to orderly movement ( No crystallization) ； T > Tc, prevent heat action of amorphous zones ( Tendency of crystal) 。 Melting point temperature of Tf all crystal disintegration.
PET dryer and dryer
hydrolysis
solid PET easy absorption of moisture from the air. Storage, the PET will hygroscopic until saturated and environmental conditions. Saturation value up to 0. A 6% weight. Usually, when the PET shipments from other suppliers, the moisture content lower than 0. A 1% weight. In order to get the best product performance, it is necessary to reduce the moisture content to zero. 004%, the best is 30 PPM before melting.
if the resin containing water, even if low will cause a series of reactions: when the temperature is higher than PET melting point ( About 250 ℃) , the water can quickly cause polymer degradation ( Due to the degradation of water chemical chain cut off) Because it will reduce the molecular weight, lower apparent viscosity and related physical properties. In fact, hydrolysis under low temperature ( Such as 150 ℃) Begin to happen, but the speed is low, its speed increased with temperature increase. Under the condition of drying and molding, IV reduction cannot be greater than zero. 02dl/g。 Reduced viscosity is too big, can lead to crystallization rate increases, adverse to the transparency of the tube billet, and resulting in a decline in the mechanical properties of the soft tube, bearing strength and impact strength decreased.
thermal degradation
the influence of temperature on the dry PET is very complex, it not only affects the rate of diffusion of water vapour, also has influence to the dry chemical process, so eventually will affect the performance of the resin. Considering potential hydrolysis and thermal process is very necessary, as mentioned above, with the
IV drop, hydrolysis accelerated at above 150 ℃, because hot transformation process is faster than diffusion process, premature drying temperature increase is unfavorable. Also, even if most of the water vapor can be siphoned off, but too high temperature ( Such as higher than 180 ℃) Will lead to the thermal degradation and thermal oxidation ( In the dry air system) So that the polymer chain rupture, also release the byproduct material, resulting in a decline in physical properties. A by-product of AA composition, physical properties of change will be expressed in the tube billet, such as
mist crystallization, IV drop, yellow, etc.
PET dryer drying principle and basic performance in desiccant bed dryer, the air is absorbed moisture first desiccant moisture absorption, a hot air blower to dry hot air pressure into the bucket. Return air through the desiccant drying cycle again, after being heated, desiccant release moisture, after cooling and absorbs moisture. So, must minimize the gas path of the two separated, desiccant and exist.
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