how to extrude hmw-ldpe film.
Although low-density polyethylene is still no stranger to most filmmakers, it is not brand new.
It has been offered in small-scale commercial form for several years, but may have been \"ahead\" by the time it debuted in early 1980 (see PT, Nov. \'84, pp. 47, 55).
USI Div last year.
Quantum chemistry Corporation
Cincinnati, feels like it\'s time to \"re-introduce\" this material because of the expansion of long-term use
Straw high density polyethylene film blowing machinery creates new opportunities for HMWHDPE.
Quantum is considered to be the only producer of this material and currently offers three levels of PetrotheneHMW-
Low density polyethylene resin, from 0. 25 to 0. 5 melt index. .
Two Olympic Games0. 925 density)
The third is EVA polymer.
Polyethylene NA 351 (0. 3 MI)
Suitable for a wide range of applications. NA 355 (0. 5 MI)
It is recommended in the most important place or where better cuts are needed. NA 357 (4. 5% VA content)
For use requiring special toughness, low toughness
Temperature characteristic, or low sealing temperature. These high-
Strength resin is also suitable for combination with other plastics by co-extrusion or mixing. With long-
Now the more common straw equipment on the market, may be re-
Through the inspection of processors, as a means to improve the utilization rate of products, and open up niche markets such as commodity bags, transparent shrink film, High
Gloss coextrusion film, heavy duty textile and heavy duty-
Custom duty production bags.
Other potential applications include ice bags, fast frozen food bags, roller liners, and clear films that need to be measured.
Comparison with other movies
Compared to traditional low density polyethylene and llannan, low density polyethylene has a higher viscosity, providing excellent bubble stability.
The combination of high viscosity and molecular chain branching gives the flow properties that allow extrusion under a wide range of operating conditions.
Due to its unique performance, HMW-
Low density polyethylene can compete with various resins in applications.
Compared with the traditional PEclarity packaging film, HMW-
Low density polyethylene is harder and has better tensile, puncture and impact strength and equivalent optical properties.
The extrusion can be long.
The stem or \"pocket\" bubbles, which usually produce better optical properties. HMW-
Low density polyethylene can also compete in heavy duty
Heavy film applications.
Compared to standard 7.
5% EVA a total of 0.
5 miles for heavy duty-
HMW-liner film on duty
The impact strength is low, but the tear resistance is good (both MD and TD)
Puncture resistance and stiffness.
Compared with 0 low density polyethylene homopolymers. 3 MI and 0.
918 density, HMW-
The impact performance of LDPEfilm is similar, the tear and stiffness are better, and the optical performance is better. Table : HMW-LDPE VS.
Other sports movies
Drop impact strength of HMW-
The thickness of low-density polyethylene per mil is higher than that of traditional low-density polyethylene, even higher than that of LLDPE.
This emphasizes long-Straw extrusion.
With the increase of the meter, the impact/mil values of the standard ldpe and llandy remain relatively constant. HMW-
For films below 1 mil, low density polyethylene has a very high impact/mil, which eventually tends to be stable at about 2 mil as the specification decreases. HMW-
Low density polyethylene also has better optical properties compared to the other two high optical properties
HMW-strength resinHDPE and LLDPE. Table : HMW-LDPE & HMW-HDPE IN LONG-
Stem extrusion melting index, total energy, feetlbTens. Str.
, PsiElongation, % 1% cut line mod.
, Psi treatment conditions long-
Stem extrusion hmw-
Either of the two standard bubbles can blow low density polyethylene into a film: a traditional \"pocket\" bubble, used with low density polyethylene, with high definition and high yield,
5 miles, unless mixed with llannan. Long-
Straw extrusion with high density polyethylene properties provides twice as much impact as impact/mil and allows stretching to 0.
Although the definition is slightly lower, but 5 mil.
By changing the type of air ring used in the process, both methods can be obtained. A dual-
The lip air ring pulls the bubbles into the air-
Ring in the shape of a traditional bubble. A single-
The lip gas ring allows bubbles to rise in the bar and expand when the tensile force overcomes its sticky elasticity.
During the rapid expansion process below the frost line, significant molecular orientation was produced, optimizing the impact strength of the film.
The high melt viscosity and molecular weight of the resin enhance this effect. HMW-
Low density polyethylene can be extruded through the groove
Feed extruder developed for HWM-HDPE long-stalk film.
The meter is usually between 0. 5 and 1. 5mil. HMW-LDPE long-
Use the same mold gap for straw extrusion-about 40mils -as for HMW-HDPE.
Extrusion under these conditions, the melting temperature can be as low as 370-
380 F, about 50 [degrees]
Lower than HMW-HDPE.
In addition, there are fewer trends --
Temperature coverage with HMW-
Because the shear heat ratio produced in the extruder is HWM-HDPE.
HMW-speed output per screw
Low density polyethylene below HMW-
High density polyethylene, which means that in order to achieve equivalent output through the groove, the speed of the extruder screw must be increasedfeed extruders.
Normally this is not a problem because HME-
Low density polyethylene is usually cooler than HMW-running and lower pressureHDPE.
For example, HMW-
Quantum runs high density polyethylene on 100-
Feed extruder with 4-in. diam.
Died at 120/hour at 125 rpm;
Watch this output with HMW
Increase screw speed to 175 rpm. HMW-
Low Density Polyethylene has the high melting strength required for a long handle.
In order to obtain symmetrical bubbles, good thickness control is possible in addition to standard gap adjustment, no special mold adjustment is required. Long-
The optical properties and puncture resistance of the stem film are not affected by the blowup ration (BUR).
However, the impact of BUR drop has increased dramatically with the increase of BUR.
MD tear strength and stiffness decrease as the drill increases.
Since these resins are harder than ordinary resins, the film blown with a large 4:1 drill has a modulus similar to the ordinary 0. 922-
Uniform density polymer film.
Get the best performance at around 3:1 BUR. TANDEM AIR-
A few years ago, former Chemplex Co.
Now merged into quantum, it is found that the tandem air ring is a way to improve the output rate and clarity of HMWLDPE long-
Straw extrusion (see PT Nov. \'84,pp. 47, 55).
The main air ring is a regular single-in-series setting-
Lip type mounted directly on the mold.
The second ring is ual-
Lip models from 30 to 51.
Above the first ring
A moderate shallow lip was found to achieve the best results.
The secondary gas ring \"locks\" The bubbles in place, increases stability and provides a high pass rate of up to 14% while reducing the high ation value by about 60%.
Although the toughness and strength of the film are reduced by tandem Air
These properties are still far higher than the traditional clarity, indicating potential measurements. Clarity of HMW-
Also, the double material is better. air-ring long-
Squeeze straw than any other method.
On the other hand, in order to achieve these benefits, it may be a bit tricky to set up a double air ring and it may take some attempts and errors.
Standard low density polyethylene film extrusion line can also be used to runLDPE.
It\'s hard to squeeze out though below 1.
With 5 mil in the pocket, good performance can be achieved on all meters.
The TD orientation caused by pocket extrusion is significantly smaller than long-
So the impact strength of the film may be lower.
Optical properties of Hmw-
When from long-
Squeeze handle to pocket.
HMW-compared to typical low density polyethylene clear film-
The pocket has better impact, stiffness and strength properties, which are perpendicular to the same.
When squeezing regular bag-shaped bubbles, 10-
30% can be dried-
Mixed into resin.
Filmgauges is as low as 0.
The application research laboratory in quantum has reached 5 mil, of which HMW-
Low density polyethylene was prepared by mixing 30% of hexene llldpe with 2. 5 MI and 0.
918 density drill at 3:1.
30% the addition of llonomia has little effect on the film fog or gloss, although \"see-
Through Clarity \"(NAS)
Relative to 100% HMW-LDPE.
Increase the tensile strength and tear strength;
And thoughtotal darts
With the addition of llannan, the drop impact energy is reduced and the puncture resistance is increased. COEXTRUDED HMW-LDPEHMW-
Low density polyethylene is also a good choice for co-extrusion.
When used as an outer layer in HMW-
Polyethylene structure, low
The density resin has a high gloss and good heat sealing.
Because it\'s natural, so
The straw extrusion, co-extrusion material has more stable bubbles, thus providing better thickness control.
It also allows to run coextrusion with high Frost lines, providing excellent directions.
Photo: high strength of HMW-
It is recommended to use low density polyethylene film in large product bags, ice bags, fast food
Freezer bag, drun liner, shrink film, heavy duty textile, even low definition film.