CN1239035A

CN1239035A - Method and apparatus for extruding out and blow moulding

Info

Publication number: CN1239035A
Application number: CN 98102264
Authority: CN
Inventors: 段启圣; 李茂松; 刘信助; 李玛琍
Original assignee: Industrial Technology Research Institute ITRI
Current assignee: Industrial Technology Research Institute ITRI
Priority date: 1998-06-15
Filing date: 1998-06-15
Publication date: 1999-12-22

Abstract

A method and apparatus for extruding out and blow moulding features that an extruder is used to heat the polyester material (PET) until it is fuxed and then to extrude it out, the fused PET flows through die to become parison, the parison is cooled by wind from wind ring the then comes in mould and finally it is shaped by blow moulding.

Description

Extrusion-blown modling manufacturing process and device thereof

Present invention is directed to a kind of extrusion-blown modling manufacturing process and device thereof, can increase substantially the resistance to impact (anti-dropping hammer property) of PET goods.

Because the PVC container has and reclaim to be difficult for and can to cause problem such as environmental pollution, and pet container character is good and cost is low, therefore PVC container market is almost replaced by pet container fully in recent years, yet this only limits to PET and penetrates and blow out to describe device, as for PET extrusion-blown modling forming containers, cause can't be by the test of dropping hammer, so a large amount of yet so far commercialization; The relevant extrusion-blown modling forming technique of following explanation earlier.

See also Fig. 4, Fig. 4 can be used to illustrate public extrusion-blown modling forming technique: PET polyester grain (raw material) 1 is sent into hopper 23, then by the dehumidifying of dehumidifying drying machine 25 and preheating it, the PET polyester grain that will dry by the fire again behind the universe is delivered in the extruder 24, PET polyester grain is heated plasticizing in the heating jacket of extruder 24, and the screw rod pressurized delivered by extruder 24 extremely exports in the die head 26 that joins with extruder 24 simultaneously, make the PET melt form a hollow tubular type embryo via die head 26, this tubular shape embryo is flowed out by mould mouth 27, then by mould 29 scope districts, matched moulds is incorporated blow needle into immediately, with blowing extension type embryo, promptly become the pet container of required form after the cooling.

In above-mentioned public extrusion-blown modling shaping processing procedure, because its type embryo of extruding is a molten mass, thus when blow molding, can't cause effective molecule orientation and crystallization, and the pet container of making at last can't be by shock-testing.

All set about from material for this research partly in the whole world at present, and expectation increases side chain and material upgrading by improving molecular weight, improves the impact strength of its PET product.IV (the intrinsic viscosity Inherent Viscosity) value of business-like at present extrusion blow level (Extrusion Blow) PET is all greater than 1.0, it increases formability by increasing side chain (as DupontPET 7067) or adding CHDM upgrading (as Kodapak PET 13339), though the impact strength of its goods has improvement, but still can't be by shock-testing, the existing market reaction is unsatisfactory.

The present invention's purpose is to provide a kind of improved extrusion-blown modling manufacturing process and device, can increase substantially the resistance to impact (anti-dropping hammer property) of its PET goods, and material need not make significantly upgrading, can reduce material cost.

The present invention system utilizes extruder that the PET polyester material is heated into melten gel and extrudes, and makes melten gel flow through die head then and becomes the type embryo, utilizes vane to blow out freezing wind with the cooling of type embryo again, makes the type embryo of this cooling enter mould and blow molding then.Because PET type embryo before entering mould, cools off it with freezing wind earlier,, improve the impact strength of goods so easily cause the molecule orientation in mould so PET type embryo is to come blowing and twin shaft to be shaped to extending with the lower temperature state.

The present invention all can obtain gratifying result to the PET polyester material of IV value more than 0.85 (containing), and material need not made significantly upgrading, can reduce material cost.

For above-mentioned purpose, feature and the advantage that makes the present invention can become apparent, hereinafter be described with reference to the accompanying drawings preferred embodiment of the present invention.Wherein:

Fig. 1 is the schematic diagram that the present invention is applied to continous way extrusion blow building mortion;

Fig. 2 A system represents one of the present invention's vane mounting means example according to Fig. 1;

Fig. 2 B system represents another example of the present invention's vane mounting means according to Fig. 1;

Fig. 3 is the schematic diagram that the present invention is applied to accumulate formula extrusion blow building mortion;

Fig. 4 is the schematic diagram of public continous way extrusion blow building mortion.

Illustrate that now the present invention is applied to the situation of continous way extrusion blow building mortion, see also Fig. 1, PET polyester grain (raw material) 1 sent into hopper 3 after batch mixer 13 evenly stirs, then by dehumidifying heat pump 15 dehumidifying and preheating it (more than 150 ℃, moisture content is below 0.05%), PET polyester grain after will drying again is delivered in the extruder 4, PET polyester grain is heated plasticizing in the heating jacket of extruder 4, and the screw rod pressurized delivered by extruder 4 extremely exports in the die head 6 that joins with extruder 4 simultaneously, make the PET melt form a hollow tubular type embryo via die head 6, this tubular shape embryo is flowed out by mould mouth 7, entering one then joins but has in the vane 8 of insulation efficiency with mould mouth 7, utilize freezing wind with tubular-type embryo surface cooling (being cooled to below 220 ℃) by 240 ℃～250 ℃, PET tubular-type embryo viscosity and melt strength are increased, fall and impel partly crystallization to prevent to manage embryo.Freezing wind is by an air blast 17 general air 2 to be squeezed in the refrigerator 16, and the temperature of wind is reduced to below 15 ℃, blows out via vane 8 inner edges, with cooling PET type embryo again.The tubular-type embryonic breeding of cooling by mould 9 scope districts, and matched moulds is incorporated blow needle into immediately, with greater than 6kg/cm ²Blast come blowing extension type embryo, promptly become the pet container of required form after the cooling.

The pet container that is shaped has burr, must further repair remove and end product.Repair the burr that remove and be admitted to pulverizer 12 rubbing slabbings, draw back batch mixer 13 then and use with 1 even mixing of PET raw material.

Compare with public extrusion-blown modling forming technique, the present invention has set up vane 8, refrigerator 16, and equipment such as air blast 17 more, make PET type embryo before entering mould 9, earlier with freezing wind with its cooling (to below 220 ℃), so PET type embryo is to come blowing and twin shaft to be shaped to extending with the lower temperature state in mould 9, improves the impact strength of goods so easily cause the molecule orientation.Refrigerator 16 and air blast 17 are known technology, therefore no longer describe in detail, introduce the structure of vane 8 below.

Vane 8 is an annulation, sees also Fig. 2 A, wherein between mould mouth and the vane 8 be with screw 82 be aided with heat insulating washer 81 link fixing, and between vane 8 and the mould mouth 7 more than F needs greater than 5mm.The purpose that spacing distance F and heat Insulation film 81 are set is to avoid the heat of mould mouth 7 to reach vane 8 and heat freezing wind.Vane 8 bodies are divided into loam cake 83 and lower cover 84, and the two engages air outlet 86 sizes of mat rotation lower cover 84 adjustable rectification campaign rings 8 by the thread rotation.In the vane body, the above baffle plate 85 of at least two circles is set, so that the freezing wind that two limits enter can evenly distribute.

Attention is in addition, manages 61 6 li former being provided with in the blowing of die head, and one of interior pipe 61 end and refrigerator 16 are joined in the present invention, in order to introduce freezing wind, blow out by mould mouth 7 then, this design can be cooled off from type embryo inside, cooperate aforementioned vane 8 effects, can make the cooling of type embryo rapider evenly.In be provided with an adiabatic space 62 between pipe 61 and the die head heart, and adiabatic space 62 two ends impose sealed, thermally insulatedly 63, and inside vacuumizes, and manages 61 and heat freezing wind in penetrating with the heat of avoiding die head 6.

Vane also can be linked to the outer rim of mould mouth 7, shown in Fig. 2 B except that being linked to the lower edge of mould mouth 7 shown in Fig. 2 A.

The present invention also is suitable for for accumulating formula extrusion blow building mortion, sees also Fig. 3, gives same label with last embodiment components identical among the figure, and omits its explanation.PET polyester grain is delivered to extruder 4, and in the heating jacket of extruder 4, be heated plasticizing and simultaneously by the storage to the accumulating device 18 of the screw rod pressurized delivered of extruder 4, after treating to accumulate enough melten gels in the accumulating device 18, utilize an oil pressure plunger 19 this melten gel that accumulates to be injected in the die head 6 that joins with it, then carry out the subsequent step identical with last embodiment.

The present invention all can obtain gratifying result to the PET polyester grain of IV value more than 0.85 (containing).Now utilize public extrusion blow forming technique (processing procedure 1) and the present invention's extrusion blow forming technique (processing procedure 2) to make the plastic cement bottle respectively, goods are done shock-testing, and the formability and the transparency that compare the two, the result as table 1 to shown in the table 4, wherein shock-testing is that the extrusion blow bottle that is shaped is filled water and capping, freely falls from height h then and hits smooth ground; And formability means that the type embryo drips vertical degree, and easily dripping hangs down then can't be shaped.Formability, impact strength, transparency level are divided into: poor, can, good, excellent level Four.

Comparing embodiment 1

Raw material: shin PET U3396 A (IV=0.96)

Flat bottle/the bottle of formed products: 400c.c. is heavy: 34g

Table 1

Comparing embodiment 2

Raw material: KURA PET KS710 B (IV=1.25)

Formed products: 1.5l round bottle/bottle is heavy: 63g

Table 2

Comparing embodiment 3

Raw material: shin PET 7644-2 (IV=1.12)

Formed products: 1.5l round bottle/bottle is heavy: 75g

Table 3

Comparing embodiment 4

Raw material: KURA PET KS710 B (IV=1.25)

Formed products: 350c.c. round bottle/bottle is heavy: 38g

Table 4

Though the front is that example explains with PET material (genus crystalline material), in fact the present invention is all suitable for crystallization and amorphous material.Though therefore the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; anyly be familiar with those skilled in the art; without departing from the spirit and scope of the invention; still can do some and change and retouching, so the present invention's protection domain should be defined with appended claim and is as the criterion.

Claims

1. extrusion-blown modling manufacturing process may further comprise the steps:

(a) the PET polyester material is heated into melten gel and extrudes;

(b) this melten gel of moulding and become the type embryo;

(c) this type embryo is lowered the temperature and increase the viscosity of this type embryo and melt strength;

(d) the type embryo blow molding that will lower the temperature.

2. extrusion-blown modling manufacturing process as claimed in claim 1 wherein, is cooled to below 220 ℃ in this type embryonal system of step (c).

3. extrusion-blown modling manufacturing process as claimed in claim 1, wherein, at the intrinsic viscosity of the PET polyester material of step (a) more than 0.85 or 0.85.

4. extrusion-blown modling building mortion comprises:

Extruder is heated into melten gel with the PET polyester material and extrudes;

Die head is linked to this extruder, and this melten gel is flowed through this die head and become the outflow of type embryo;

Heat sink is used for this type embryo cooling;

Mould is used so that the type embryo of this cooling enters the blow molding then of this mould.

5. extrusion-blown modling building mortion as claimed in claim 4 wherein also comprises an accumulating device, is connected between this extruder and this die head, and the melten gel of being extruded by this extruder is introduced into this accumulating device and stores, and delivers to this die head again after waiting to accumulate both quantitative melten gel.

6. as claim 4 or 5 described extrusion-blown modling building mortions, wherein, this heat sink system is made up of the air blast that joins in regular turn, refrigerator and vane, and this air blast is squeezed into air this refrigerator and become cold air, by this vane this cold air is blown in this type embryo then and lowers the temperature.

7. extrusion-blown modling building mortion as claimed in claim 6, wherein, the mould mouth lower edge of this die head is fixed in this vane system.

8. extrusion-blown modling building mortion as claimed in claim 7 wherein, stays a set interval between the mould mouth of this vane and this die head.

9. extrusion-blown modling building mortion as claimed in claim 8, wherein, this is at interval greater than 5mm.

10. extrusion-blown modling building mortion as claimed in claim 7, wherein, a side surface of facing this mould mouth at this vane also is provided with heat insulating washer.

11. extrusion-blown modling building mortion as claimed in claim 6, wherein, the mould mouth outer rim of this die head is fixed in this vane system.

12. extrusion-blown modling building mortion as claimed in claim 11 wherein, stays a set interval between the mould mouth of this vane and this die head.

13. extrusion-blown modling building mortion as claimed in claim 12, wherein, this is at interval greater than 5mm.

14. extrusion-blown modling building mortion as claimed in claim 11, wherein, a side surface of facing this mould mouth at this vane also is provided with heat insulating washer.

15. extrusion-blown modling building mortion as claimed in claim 6 wherein, still be provided with pipe in this die head, and one of pipe end is connected with this refrigerator in being somebody's turn to do, the blow cold air that the other end then produces this refrigerator is in this type embryo inside.

16. extrusion-blown modling building mortion as claimed in claim 15 wherein, is provided with a vacuum heat-insulation chamber between pipe and this die head in this, reaches in this with the heat that completely cuts off this die head and manages.

17. extrusion-blown modling building mortion as claimed in claim 16, wherein, this vacuum heat-insulation chamber system seals with adiabatic material.