CN1166506C - Single-screw extruder for hard polyvinyl chloride - Google Patents

Abstract

The present invention relates to a new technique for a single-screw extruder for hard polyvinyl chloride. The size of spiral flute depth at an outlet of a screw compression section is reduced, so the geometric compression ratio of the screw compression section is enlarged, the conveying pressure of materials is reinforced and a shallow slot banburying section is arranged at the outlet of the screw compression section. The spiral flute depth of the shallow slot banburying section is from 0.1mm to 1mm. A deep slot pushing section is arranged at an outlet of the shallow slot banburying section, and spiral flute depth at an outlet of the deep slot pushing section is from 1mm to 4mm. Product materials produced by the new technique of the present invention has high density. Under the same quality requirement, a proportion of filling materials can be increased, and thus, the cost of an original auxiliary material formula is reduced by 30%; the accommodation of used raw materials is wide; high molecular weight resin with large processing viscosity number can be used; a proportion of a lubricating agent can be reduced; the produced product material of the present invention has the advantages of strong shock resistant force, good toughness, light surface, good ageing resistance, little investment of machinery equipment, good operational stability, low repairing cost of the machinery equipment and obvious energy saving effect.

Description

A kind of RPVC single-screw extruder that is used for

Technical field

What the present invention relates to is a kind of single screw rod and application thereof that RPVC is extruded that be used for.Belong to the plastics machinery field.

Background technology

The extrusion system of single screw extrusion machine is made up of machine barrel and single screw rod, and screw rod is a critical piece, and by its rotation, the material in the machine barrel just can be moved, and obtains the frictional heat of supercharging and part, quantitatively is transported to head and moulding to level pressure behind the mixing.According to the three kinds of physical state change procedures of plastics material in extruder and the job requirement at each position of screw rod, usually screw rod is divided into three sections of feeding section (claim not only solid conveying section), melt zone (claim not only compression section) and homogenizing zones (but also claiming metering section), wherein the outlet of feeding section promptly is the import of melt zone, and the outlet of melt zone promptly is the import of homogenizing zone.The effect of feeding section is that convey materials is given melt zone and homogenizing zone; The effect of melt zone is compacting material and fused materials; The effect of homogenizing zone is that the material from melt zone is further sent into head the even and quantitative level pressure constant temperature of plasticizing.

The extrusion of tradition RPVC list screw rod extruding technology is described below: before the start, by outer heater machine barrel is carried out preheating, make barrel zone temperature be controlled to be the temperature required of the preliminary fusion of RPVC energy, starter motor then, the screw rod rotation, RPVC mixture (hereinafter to be referred as material) is entered machine barrel from loading hopper, and material is to be solid-state shape, is fed forward under the effect of screw rod rotation.After material enters melt zone from feeding section along with material continue be fed forward, because the degree of depth of screw channel shoals gradually, and the inhibition of screen pack, flow distribution plate and head, material further is compacted, meanwhile, material is subjected to the heating from the outer heater of machine barrel again, material temperature constantly raises, fused materials (being called liquid phase or molten bath) amount constantly increases, the solid material of fusion (being called solid phase or Solid Bed) amount does not then constantly reduce, to the melt zone end, whole or most of fusions of material and change viscous state into.After material enters homogenizing zone, further plastified and homogenising, and made it to clamp-on head.In more than describing, reflect that clearly material is heated to be from solid-state that to melt to the plasticizing process that is heated into viscous state very long, this is because the melt zone geometrical compression ratio of traditional single screw rod is little at present, is generally 2-5 doubly, and melt zone exit spiral groove depth size is big, be generally 2mm-4mm, thereby make between material and machine barrel, material and screw rod, material and the material friction level low, material plasticizing can only rely on the external world to heat, thus material inside be heated very slow, melting time is long, and plasticizing process is slow.Because polyvinyl chloride self has the thermal degradation tendency, if plasticizing process is slow, must cause material thermal degradation phenomenon in process serious, plasdcizing rate is low, and polyvinyl chloride primary particle nuclear is opened only below 60%～70%; Again owing to import, the outlet spiral groove depth of traditional single screw rod homogenizing zone are measure-alike, in the material plasticizing course of conveying, material becomes viscous state substantially when the screw rod melt zone, after being subjected to the inhibition of screen pack, flow distribution plate and head etc., material is fed forward difficulty, cause feed back, leakage current, skidding serious, this has also directly influenced the compacting of melt zone material and the effect and the efficient of material plasticizing, thereby causes the every performance indications of material of the RPVC product that traditional single screw rod extruding technology produces quite low.Because in the extrusion of this traditional single screw rod extruding technology, material plasticizing efficient is low, lack of homogeneity, production efficiency are low, product quality can't be stablized, yield rate is low, and therefore traditional single screw rod is extruded the RPVC technology and is eliminated substantially.

Summary of the invention

The objective of the invention is to the defective that exists at above-mentioned conventional art, overcome that single screw rod extruding technology melting effect is poor, the shortcoming of material lack of homogeneity, propose a kind of single screw rod new technology that RPVC is extruded that is used for.Technical solution of the present invention: include feeding section, screw compression section, feeding section is located at the leading portion of screw compression section, and shallow slot banburying section is set in the exit of screw compression section, and the spiral groove depth of shallow slot banburying section is 0.1mm-1mm; Deep trouth is set in the exit of shallow slot banburying section pushes section, the exit spiral groove depth that deep trouth pushes section is 1mm-4mm.Employing reduces screw compression section outlet spiral groove depth size, strengthen the geometrical compression ratio of compression section, strengthen the material discharge pressure, and shallow slot banburying section is set in the exit of compression section, thereby effectively strengthen the friction level between material and machine barrel, material and screw rod, material and the material, make material under high pressure obtain abundant banburying, quicken self plasticizing efficiency of material, improve the uniformity of material.Owing to be provided with shallow slot banburying section, can reduce the conveying capacity of plastic state material.Therefore, deep trouth is set in the exit of shallow slot banburying section pushes section, the outlet groove depth of shallow slot banburying section is progressively strengthened, toward head, mould enough propelling movement abilities are arranged to guarantee the plastic state material.The present invention has strengthened the geometrical compression ratio of compression section, improved the discharge pressure of material, shortened material plastifies into the viscosity flow shape from the solid shape fusion time significantly, because fusion time is short, suppressed the thermal degradation phenomenon of polyvinyl chloride in process effectively, the viscous state material passes through shallow slot banburying section again, under high pressure is able to abundant banburying, makes the primary particle opening degree of polyvinyl chloride can reach more than 90%; Push section owing to be provided with deep trouth in the exit of screw rod, strengthened the propelling movement ability of viscous state material, improved the pressure of material in head, mould, thereby strengthened the material density of goods significantly.Utilize this technology, make single screw extrusion machine can not only produce the chemical building material that meets state quality standard, and can be aspect multinomial technical parameter and technical indicator, and can produce, produce the chemical building material of very special quality requirement considerably beyond the expensive advanced twin-screw extruding technology of investment.

Advantage of the present invention:

1, utilization the technology of the present invention, because the material plasticizing time is short, in the raw and auxiliary material prescription, be used to contain the stabilizing agent of polyvinyl chloride thermal degradation tendency can be few significantly with or even do not use, owing to material pressure in machine barrel is big, material density height is under equal quality requires simultaneously, can increase the inserts ratio greatly, more than two factors can reduce the composition of raw materials cost up to about 30%;

2, use the raw material wide accommodation, can use the big super high molecular weight resin of processing viscosity number, and can reduce the ratio of lubricant, provide advantage for improving quality of item;

3, the product material density height of Sheng Chaning can be produced the twin-screw production technology high density product that is beyond one's reach, and anti-impact force is strong, good toughness, surface-brightening, and ageing resistace is good;

4, the plant equipment investment is little, and its investment is less than 1/10th of advanced twin-screw extrusion equipment, and operational stability is good, and the machinery maintenance cost is low;

5, energy-saving effect is remarkable, than prior art energy savings about 20%.

Accompanying drawing 1 is the single screw rod schematic diagram in the conventional art

Accompanying drawing 2 is single screw rod schematic diagrames of the present invention

In the accompanying drawing 1 is feeding section, the 2nd, compression section, the 3rd, and shallow slot banburying section, the 4th, deep trouth pushes section, the 5th, homogenizing zone

Implementation method

Embodiment 1: 2 described screw rods in conjunction with the accompanying drawings, and selecting the extruder bore for use is ф 65mm, and the feed opening degree of depth of screw rod is 8mm, and the groove depth of shallow slot banburying section 3 is 0.1mm, and the outlet groove depth that deep trouth pushes section 4 is 1mm;

Embodiment 2: 2 described screw rods in conjunction with the accompanying drawings, and selecting the extruder bore for use is ф 65mm, and the feed opening degree of depth of screw rod is 8mm, and the groove depth of shallow slot banburying section 3 is 0.3mm, and the outlet groove depth that deep trouth pushes section 4 is 1.5mm;

Embodiment 3: 2 described screw rods in conjunction with the accompanying drawings, and selecting the extruder bore for use is ф 65mm, and the feed opening degree of depth of screw rod is 8mm, and the groove depth of shallow slot banburying section 3 is 1mm, and the outlet groove depth that deep trouth pushes section 4 is 4mm;

It is 22 kilowatts that above-mentioned three embodiment all adopt power of motor, 44 rev/mins of screw speeds, before the start, with heater machine barrel is carried out preheating, temperature is added to adapts to when starting shooting, starter motor, make the screw rod rotation, material is solid-state in loading hopper adding machine barrel, in extrusion, the material in the feeding section 1 enters in the screw compression section 2, along with screw compression section 2 spiral groove depths shoal rapidly, and flow distribution plate and head inhibition under, material is compacted very soon, when pressure increases sharply, again because the groove depth of screw rod shallow slot banburying section 3 has only 0.1mm, 0.3mm, 1mm, therefore, material and machine barrel, material and screw rod, frictional force between material and the material also strengthens rapidly, yet produces strong mixing and shear action, 2 rapid plasticizings are the viscous state material in the compression section to make solid material, carry out the high pressure banburying thereby enter shallow slot banburying section 3, push section 4 by deep trouth again material is clamp-oned head, mould cools off then, typing.

Formula for a product cost of the present invention is low, and manufacturing cost is low, and the product material of manufacturing is tight, the hardness height, and anti-impact force is strong, and good toughness improves the engineering application power of product greatly, and its economic benefit and obvious social benefit have a extensive future.

Claims (1)

1, a kind of RPVC single-screw extruder that is used for, include feeding section (1), screw compression section (2), feeding section (1) is located at the leading portion of screw compression section (2), it is characterized in that in the exit of screw compression section (2) shallow slot banburying section (3) being set, the spiral groove depth of shallow slot banburying section (3) is 0.1mm-1mm; Deep trouth is set in the exit of screw rod shallow slot banburying section (3) pushes section (4), the exit spiral groove depth that deep trouth pushes section (4) is 1mm-4mm.

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