CN1038990C - Multi-side thread-groove convective screw - Google Patents
Multi-side thread-groove convective screw Download PDFInfo
- Publication number
- CN1038990C CN1038990C CN92114886A CN92114886A CN1038990C CN 1038990 C CN1038990 C CN 1038990C CN 92114886 A CN92114886 A CN 92114886A CN 92114886 A CN92114886 A CN 92114886A CN 1038990 C CN1038990 C CN 1038990C
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- Prior art keywords
- screw channel
- section
- effect
- screw
- screw rod
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/50—Details of extruders
- B29C48/505—Screws
- B29C48/59—Screws characterised by details of the thread, i.e. the shape of a single thread of the material-feeding screw
Abstract
The present invention belongs to improvement for a screw rod used for extrusion and injection. A melting section or/and a metering section of the screw rod is/are provided with a milling-melting section (an HP section for short). The HP section has the structure that the bottom of a spiral slot is in a regular polygon shape, and a multi-head spiral edge is arranged on the screw rod. The HP section generates branching effect, convection effect, pressurization and decompression effect, elongational flow effect, shearing effect, surface updating effect, calendering effect, continuous velocity distribution changing effect, etc. on a polymer, and realizes dispersing melting. Experiment shows that the milling and melting performance is higher than that of a double-slot corrugating screw rod. The present invention has low power consumption and uniform polymer temperature distribution. Thus, the present invention is especially suitable for high milling situations such as blending, copolymerization, filling and modification, and can perform the function at a high speed.
Description
The present invention relates to polymer processing field, it belongs to extrudes or a kind of improvement of injection screw rod.
Extrude or the common three-stage screw of injection, use till today because of it is simple in structure.But it exists, and melting rate is low, mixing behavior difference and shortcomings such as inhomogeneous and power consumption height, to such an extent as to the radial temperature difference of extruder or injector exit melt is big, influence mechanical performance, electrical property and the optical property of goods, even may make goods hallrcuts occur, reduce yield rate.For many years, people have done many improvement to common three-stage screw.At US--4, the wavy screw rod of a kind of double flute is disclosed in 173,417, its purpose is to improve fusion and mixing behavior.Its formation is barrier spiral shell rib to be set screw channel is divided into wide two halves, and spiral groove depth becomes cyclically-varying, and two halves screw channel waveform is anti-phase.There is following weak point in it:
1. owing to be provided with the barrier rib in wavy section of double flute two fens screw channels are separated, so generally have only melt just can cross the barrier rib convection current takes place, solid particle then is retained in the screw channel, can not cross the barrier rib and participates in the convection current between the screw channel in two fens.
2. for above-mentioned reasons, if double flute is arranged on melt zone for wavy section, can only place this section latter half.Therefore, can't give full play to the advantage of wavy section of double flute.
3. in wavy section of double flute, when polymer flowed a circle along screw channel, melt flowed back and forth that number of times for once in " supercharging-decompression " that is subjected to polymer between two fens screw channels.
4. in wavy section of the double flute, effects such as the shunting that polymer is subjected to, calendering, shearing, Surface Renewal and VELOCITY DISTRIBUTION change are very little or less.
Therefore, the fusion of the wavy screw rod of double flute and mixing behavior are also not really high, generally also other mixing elements will be set during use.
The objective of the invention is at having the weak point that various screw rods exist both at home and abroad now, start with from the structure of improving screw channel, spiral shell rib, develop a kind of screw rod with fusion efficiently and mixing combination property, to adapt to high mixing requirement, improve the added value of goods as blend, copolymerization, filling and enhancing.
Purpose of the present invention can reach by following measure:
A kind of by polygon screw channel convection type screw rod that feed zone, melt zone and metering section constituted, it is characterized in that melt zone or/and metering section is provided with mixing-melt zone, the structure of this mixing-melt zone is: the screw channel bottom is regular polygon, its limit number is got D/10 at most, round numbers, wherein D represents screw diameter, and its unit is a millimeter, and the limit is counted minimum and got 3; Screw rod is provided with bull spiral shell rib, and a number of its spiral shell rib is identical with the limit number of screw channel bottom regular polygon.
The structure of mixing-melt zone (being called for short the HP section) has produced multiple effect to polymer.Explain its mechanism and operation principle below by these effects.
At first, just be divided into multiply and flow, promptly produce shunt effect when polymer enters the HP section.Its number of share of stock also is that bottom land limit number is identical with spiral shell rib head number.
Second, polymer enters on the screw channel certain on one side the time, shown in Figure 2 as screw channel expanded view and polymer flow signal, because the degree of depth of section start A half screw channel is less, resistance is bigger, the situation of B half screw channel is then just in time opposite, and this makes in the most B of inflow of polymer half screw channel, with existing mixed with polymers in B half screw channel; Then, A half screw channel deepens gradually, B half screw channel is then corresponding to shoal, make most polymer in B half screw channel flow into A half screw channels and with A half screw channel in existing mixed with polymers, each limit of screw channel all makes most polymer flow once back and forth in the two halves screw channel, and its number of times that flows back and forth was identical with bottom land limit number when polymer flowed a circle along screw channel.Be the such convection current of most of polymer generation in the two halves screw channel: B → A → B → A ..., make polymer be subjected to abundant convection current melange effect.
The 3rd, because the two halves screw channel by shoaling deeply, more from light to dark, constantly repeats, the number of times that repeats in every circle screw channel is identical with bottom land limit number, and this makes polymer be subjected to " supercharging-decompression " effect of corresponding number of times.
The 4th, the uniqueness of groove depth change strengthened the screw channel interpolymer along laterally with flowing radially, produced the extension flowing effect.
The 5th, when polymer flows a circle along screw channel, the turning that must cross the screw channel bottom repeatedly, its number of times is identical with bottom land limit number.This moment, polymer was approached into many thin layers because of being subjected to shear action by being cut, and made its surface continual renovation.Stratiform circulation takes place at the place, forward and backward position at bottom land turning in polymer, has promptly produced rolling effect.
The 6th, because the screw channel bottom is the unique distribution of regular polygon and groove depth, the VELOCITY DISTRIBUTION of screw channel interpolymer is changed by continuous several times ground, and polymer unit is rearranged continually.
Fig. 1 is the structural representation of mixing-melt zone (abbreviating the HP section as) of 4 for bottom land limit number.
Fig. 2 is mixing-melt zone of the 4 screw channel expanded view and polymer flow schematic diagram of (tube is called the HP section) for bottom land limit number.
Fig. 3 is the stratiform circulation schematic diagram of the forward and backward formation in bottom land turning of mixing-melt zone (abbreviating the HP section as) of 4 for bottom land limit number.
Fig. 4 is the structural representation of mixing-melt zone (abbreviating the HP section as) of 8 for bottom land limit number.
The invention will be further described below in conjunction with drawings and Examples.
One screw diameter D is 45 millimeters, and its melt zone and metering section are provided with HP section as shown in Figure 1.The screw channel bottom 2 of HP section is square, and screw rod is provided with spiral shell rib 1, and its number is four, and promptly the limit number with the screw channel bottom is identical.As shown in Figure 2, at the I-I section, two halves screw channel A is identical with the mean depth of B; At the II-II section, the mean depth of A half screw channel is bigger than B half screw channel; The situation at III-III place, cross section is opposite with section II-II just in time.In each circle screw channel, all repeat above-mentioned groove depth Changing Pattern, its groove depth change frequency is identical with the limit number of screw channel bottom, and present embodiment is four times.The HP section has constituted the construction unit of a series of repetitions, and the groove depth of each construction unit all by rule as above variation takes place once.In Fig. 3,3 is machine barrel, and 4 is screw rod, and 5 is the screw channel bottom corners, the stratiform circulation that forms before and after 6 expression screw channel bottom corners, 5 places.In the limit number of screw channel bottom is four HP section, when polymer when screw channel flows a circle, before and after the bottom land turning, form eight stratiform circulation 6, make polymer be subjected to rolling effect, further strengthen fusion and mixing function; Simultaneously polymer also will be crossed the turning 5 four times of screw channel bottom, is subjected to certain shear action, is approached into many thin layers and cut, and makes its surface constantly obtain upgrading, and has improved heat transfer property greatly.
One screw diameter D is 120 millimeters, it melt zone or metering section on as shown in Figure 4 HP section is set.The screw channel bottom 2 of HP section is octagon, and screw rod is provided with spiral shell rib 1, and its number is eight, and promptly the limit number with the screw channel bottom is identical.Operation principle is with embodiment 1.In each circle screw channel, its groove depth change frequency is eight times, and 16 stratiform circulation of the forward and backward formation in screw channel bottom corners place make polymer be subjected to rolling effect, and simultaneously polymer also will be crossed the turning eight times of screw channel bottom.
The present invention compared with prior art has following advantage:
1, in wavy section of double flute, when polymer flowed a circle along screw channel, melt only took place to flow back and forth once, And in the HP section, polymer flows back and forth, " supercharging-decompression " number of times is identical with the limit number of screw channel bottom. Because mixing behavior improves with increasing of above-mentioned number of times, effectively strengthened mixed so be provided with the screw rod of HP section The refining function.
2, in the HP section, admittedly molten two components all are in the continuous Convection states, strengthened the horizontal of them With Radial Flow, produced calendering, cut thin and the Surface Renewal effect, greatly improved heat transfer property, strengthened Mixing-the melting function.
3, because advantage 1,2 makes the HP section have the mixing and dispersion milling performance of very high distribution.
4, the structure of HP section makes solid particle and the melt all can convection current between the two halves screw channel, so can be molten The section of melting top arranges the HP section, and it is broken hard Solid Bed gradually, and solid particle is dispersed in the melt-flow, Form solid-melt blend, realized " dispersion melting mechanism ", its melting behaviour ratio is obeyed classical The screw rod of Maddock melting mechanism is much higher.
5, HP section screw rod is obeyed " dispersion melting mechanism ", can reduce the required mechanical output consumption of melting. When screw speed is 100r/min, be respectively with the power-law exponent that represents melt viscosity 0.34, LDPE, HDPE and these three kinds of plastics of LLDPE of 0.50 and 0.60 Be example, mechanical output reduction amplitude is respectively 29%, 35% and 39%. Melt viscosity is more big, melting It is more big that mechanical output consumption reduces amplitude, and visible HP section screw rod is more favourable for processing high viscosity polymer, has Solved to effect the problem that requires high power motor when adopting common screw.
6, because in the HP section, solid particle is dispersed in the melt, the contact-making surface between solid and the melt two-phase Long-pending is that heat transfer area increases greatly, and solid temperature can raise quickly. The temperature difference of melt and solid is littler, and is namely molten The section of melting screw channel interpolymer temperature distribution uniform. In addition, the mean temperature of polymer is lower.
7, " dispersion melting " can accelerate melting, reduce melting length, and rotating speed is more high, melting length subtracts Little amplitude is also more big, and therefore, HP section of the present invention more can be made the most of the advantage under high speed.
Claims (1)
1, a kind of by polygon screw channel convection type screw rod that feed zone, melt zone and metering section constituted, it is characterized in that melt zone or/and metering section is provided with mixing-melt zone, the structure of this mixing-melt zone is: the screw channel bottom is regular polygon, its limit number is got D/10 at most, round numbers, wherein D represents screw diameter, and its unit is a millimeter, and the limit is counted minimum and got 3; Screw rod is provided with bull spiral shell rib, and a number of its spiral shell rib is identical with the limit number of screw channel regular polygon that the bottom is; The degree of depth of arbitrary limit screw channel is all by following cyclically-varying: along the Flow of Goods and Materials direction, left and right two halves screw channel, the mean depth of left half screw channel of elder generation is littler than right half screw channel, and the mean depth of two halves screw channel is identical then, and the mean depth of last left half screw channel is bigger than right half screw channel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN92114886A CN1038990C (en) | 1992-12-24 | 1992-12-24 | Multi-side thread-groove convective screw |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN92114886A CN1038990C (en) | 1992-12-24 | 1992-12-24 | Multi-side thread-groove convective screw |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1077158A CN1077158A (en) | 1993-10-13 |
| CN1038990C true CN1038990C (en) | 1998-07-08 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN92114886A Expired - Fee Related CN1038990C (en) | 1992-12-24 | 1992-12-24 | Multi-side thread-groove convective screw |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1038990C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102501348B (en) * | 2011-09-28 | 2014-06-11 | 华南理工大学 | Preparation method of high polymer material scaffolds for tissue engineering |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52136264A (en) * | 1976-05-12 | 1977-11-14 | Toshiba Machine Co Ltd | Mixing extruder |
| JPS5597943A (en) * | 1979-01-22 | 1980-07-25 | Nakatani Kikai Kk | Kneading extruder |
| JPS5967028A (en) * | 1982-10-09 | 1984-04-16 | Mitsubishi Heavy Ind Ltd | Highly kneading screw |
| JPS59103733A (en) * | 1982-12-06 | 1984-06-15 | Mitsubishi Heavy Ind Ltd | Efficient kneading screw |
| JPS59103732A (en) * | 1982-12-06 | 1984-06-15 | Mitsubishi Heavy Ind Ltd | Efficient kneading screw |
-
1992
- 1992-12-24 CN CN92114886A patent/CN1038990C/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52136264A (en) * | 1976-05-12 | 1977-11-14 | Toshiba Machine Co Ltd | Mixing extruder |
| JPS5597943A (en) * | 1979-01-22 | 1980-07-25 | Nakatani Kikai Kk | Kneading extruder |
| JPS5967028A (en) * | 1982-10-09 | 1984-04-16 | Mitsubishi Heavy Ind Ltd | Highly kneading screw |
| JPS59103733A (en) * | 1982-12-06 | 1984-06-15 | Mitsubishi Heavy Ind Ltd | Efficient kneading screw |
| JPS59103732A (en) * | 1982-12-06 | 1984-06-15 | Mitsubishi Heavy Ind Ltd | Efficient kneading screw |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1077158A (en) | 1993-10-13 |
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| C14 | Grant of patent or utility model | ||
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| C15 | Extension of patent right duration from 15 to 20 years for appl. with date before 31.12.1992 and still valid on 11.12.2001 (patent law change 1993) | ||
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