WO2021027071A1

WO2021027071A1 - Method for manufacturing biaxially stretched pvc pipe

Info

Publication number: WO2021027071A1
Application number: PCT/CN2019/113633
Authority: WO
Inventors: 何志才; 陈卫; 黄剑; 陈智勇
Original assignee: 永高股份有限公司
Priority date: 2019-08-13
Filing date: 2019-10-28
Publication date: 2021-02-18
Also published as: CN110341173A

Abstract

A method for manufacturing a biaxially stretched PVC pipe, comprising an air-blowing pipe (1), an air-blowing pipe positioning and reciprocating device, a heating device (6), an expansion shaping device (8), a cooling device (9), and a traction device. The traction device comprises a first traction means (5) and a second traction means (10). An expansion pipeline (7) is fixed on the tail end of the air-blowing pipe (1). One end of the air-blowing pipe (1) is connected to an extruder head. The air-blowing pipe (1) is fixed by the air-blowing pipe positioning and reciprocating device and performs reciprocating motion within a certain range. The specific production process comprises: an extruder produces a thick-walled pipe blank (20); after being cooled and shaped, the pipe blank (20) is performed the first axial stretching by the first traction means (5); the heating device (6) heats the pipe blank (20) performed the first axial stretching to 110-150ºC; the expansion shaping device (8) performs expansion shaping on the pipe blank (20) completed heating; the cooling device (9) cools the pipe blank (20) completed expanding for 15-30 s; the cooled pipe blank (20) enters the second traction means (10). The manufacturing method is low in processing cost, and the manufactured pipe has uniform thickness and uniform overall performance.

Description

A method for preparing biaxially stretched PVC pipe

Technical field

The invention relates to the technical field of polymer materials, in particular to a method for preparing biaxially stretched PVC pipes.

Background technique

Due to its high modulus, high strength and low price, PVC pipe is the most widely used plastic piping system in the world, and it has been widely used in many areas of modern society. my country's plastic pipe industry has developed rapidly and has become one of the world's largest countries in the production and application of plastic pipes. However, PVC pipes also have some shortcomings: poor high temperature resistance, easy to deform when working in a hot environment, not suitable for hot water pipes; low toughness and strength, and poor resistance to cracking and impact.

Biaxially oriented polyvinyl chloride (PVC-O) pipes are pipes manufactured through a special orientation process. This process is to stretch the PVC-U pipes produced by extrusion methods in axial and radial directions. The long-chain PVC molecules in the pipe are arranged biaxially to obtain a new type of PVC pipe with high strength, high toughness, high impact resistance and fatigue resistance, which is far better than ordinary PVC-U pipes. The research and development of PVC-O pipes can greatly save raw material resources, reduce costs, improve product performance, and have obvious economic and social benefits.

The existing production process of PVC-O pipes expands the PVC pipes in sections, and only expands the joints of the expanded pipes once, which leads to the easy de-orientation of the PVC pipes at the joints and affects the overall performance of the PVC-O pipes. .

Summary of the invention

In order to overcome the above-mentioned problems in the prior art, the present invention proposes a method for preparing biaxially stretched PVC pipes.

The technical solution adopted by the present invention to solve its technical problems is: a method for preparing biaxially stretched PVC pipes, including blowing pipe, blowing pipe positioning and reciprocating device, heating device, expansion setting device, cooling device and traction device. The traction device includes a first traction device and a second traction device, the end of the blowing tube is fixed with an expansion cloth tube, one end of the blowing tube is connected with the extruder head, and the blowing tube is fixed by the blowing tube positioning and reciprocating device And realize the reciprocating movement within a certain range; the specific production process is: the extruder produces thick-walled tube blanks, after cooling and shaping, the first traction device performs the first axial stretching, and the heating device will pass through the The first-time axially stretched tube is heated to 110-150°C, the expansion and setting device expands and sets the heated tube, and the cooling device cools the expanded tube for 15-30 seconds. The cooled billet enters the second traction device.

In the above-mentioned method for preparing a biaxially stretched PVC pipe, the blowing tube positioning and reciprocating device includes a blowing tube support, a spring fixed end and a spring.

In the above-mentioned method for preparing a biaxially stretched PVC pipe, the speed ratio of the first traction device and the second traction device is 1.1 to 3.

In the above-mentioned method for preparing biaxially stretched PVC pipes, the expansion and shaping device includes an air cylinder, a fixed template, a guide rod, a movable template, and a stereotype mold. The stereotype mold is fixedly installed on one side of the movable template. The other side is fixedly connected with the cylinder piston, the cylinder is fixedly installed on the fixed template, the guide rod penetrates the movable template and the fixed template, and the expansion and setting device can realize linear reciprocating motion.

In the above-mentioned method for preparing biaxially stretched PVC pipes, the shaping die is respectively provided with an expansion section, a transition section and a shaping section along the movement direction of the tube blank, and the length ratio of the expansion section, the transition section and the shaping section is 2: 1:2, the temperature of the expansion section is set to 130-135°C, the temperature of the transition section is set to 110-120°C, and the temperature of the shaping section is set to 80-95°C.

In the above-mentioned method for preparing biaxially stretched PVC pipes, the working process of the expansion setting device is: after the tube blank reaches the expansion setting device, the setting mold is closed while the pipe is expanded and inflated, and the expansion pressure is maintained after the expansion pipe is full. At the same time, the expansion tube and the shaping mold move forward synchronously with the tube blank. After reaching a certain position, the expansion tube deflates and the shaping mold opens. The expansion tube and shaping mold quickly return to the starting position at the same time, and the expansion process is repeated.

In the above-mentioned method for preparing a biaxially stretched PVC pipe, the expansion pressure of the expansion setting device is 0.2-0.5 MPa when it is working.

The beneficial effect of the present invention is that the method for preparing biaxially stretched PVC pipes provided by the present invention effectively solves the problem of molecular chain de-orientation at the pipe joints during segmented expansion, and ensures the overall performance of the biaxially stretched PVC pipes. The invention realizes the continuous operation of the biaxial stretching tube, has simple structure, precise control, easy to realize industrialization, saves energy consumption, and reduces production costs; the invention has simple operation, low processing cost, raw material saving, and uniform thickness of the prepared tube , The overall performance is uniform.

Description of the drawings

The present invention will be further described below in conjunction with the drawings and embodiments.

Figure 1 is a schematic diagram of the production process of the present invention;

Fig. 2 is a schematic diagram of the expansion setting device along the direction A in Fig. 1;

Figure 3 is a sectional view of the shaping mold;

Figure 4 is a schematic diagram of the continuous working cycle of the expansion pipe.

In the figure: 1. Blow pipe, 2. Blow pipe support, 3. Spring fixed end, 4. Spring, 5. First traction device, 6. Heating device, 7. Expanding cloth pipe, 8. Expanding setting device, 9. Cooling Device, 10. Second traction equipment, 11. Cylinder, 12. Fixed template, 13. Guide rod, 14. Moving template, 15. Shaping mold, 16. Cylinder piston, 17. Expansion section, 18. Transition section, 19. Shaping section, 20. Tube blank.

detailed description

To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

A method for preparing a biaxially stretched PVC pipe, including a blowing tube 1, a blowing tube positioning and reciprocating device, a heating device 6, an expansion setting device 8, a cooling device 9, and a traction device, the traction device including a first traction device 5 And the second traction device 10, the end of the blowing tube 1 is fixed with an expanding cloth tube 7, one end of the blowing tube 1 is connected with the extruder head, the blowing tube 1 is fixed by the blowing tube positioning and reciprocating device and fixed at a certain The reciprocating movement is realized within the range; the specific production process is: the extruder produces the thick-walled tube 20. After cooling and shaping, the first traction device 5 performs the first axial stretching, and the heating device 6 passes through the The primary axially stretched tube 20 is heated to 110-150°C, the expansion and setting device 8 expands and sets the heated tube 20, and the cooling device 9 cools the expanded tube 20 15 In ~30s, the cooled tube blank 20 enters the second traction device 10.

Further, the blowing tube positioning and reciprocating device includes a blowing tube support 2, a spring fixed end 3, and a spring 4.

Further, the speed ratio of the first traction device 5 and the second traction device 10 is 1.1-3.

Further, the expansion setting device 8 includes an air cylinder 11, a fixed template 12, a guide rod 13, a movable template 14, and a setting mold 15. The setting mold 15 is fixedly installed on one side of the movable template 14 and the other of the movable template 14 The side is fixedly connected with the cylinder piston 16, the cylinder 11 is fixedly installed on the fixed template 12, the guide rod 13 penetrates the movable template 14 and the fixed template 12, and the expansion and setting device 8 can realize linear reciprocating motion.

Further, the shaping die 15 is respectively provided with an expansion section 17, a transition section 18 and a shaping section 19 along the movement direction of the tube blank 20. The length ratio of the expansion section 17, the transition section 18 and the shaping section 19 is 2:1:2. The temperature of the expansion section 17 is set to 130-135°C, the temperature of the transition section 18 is set to 110-120°C, and the temperature of the shaping section 19 is set to 80-95°C.

Further, the working process of the expansion setting device 8 is: after the tube blank 20 reaches the expansion setting device 8, the setting mold 15 is closed while the expanded cloth tube 7 is inflated. After the expanded cloth tube 7 is full, the expansion pressure is maintained while expanding the cloth tube 7 Synchronously move forward with the shaping mold 15 along with the tube blank 20. After reaching a certain position, the expanded cloth tube 7 is deflated and the shaping mold 15 is opened. The expanded cloth tube 7 and the shaping mold 15 quickly return to the starting position at the same time, and the expansion is repeated. process.

Further, the expansion pressure of the expansion setting device 8 is 0.2-0.5 MPa when working.

The above embodiments are only exemplary embodiments of the present invention and are not used to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions should also be regarded as falling within the protection scope of the present invention.

Claims

A method for preparing biaxially stretched PVC pipes, including blowing pipe (1), blowing pipe positioning and reciprocating device, heating device (6), expansion setting device (8), cooling device (9) and traction device, and its characteristics The traction device includes a first traction device (5) and a second traction device (10), an expansion tube (7) is fixed at the end of the blowing tube (1), and one end of the blowing tube (1) is connected to the extruder. The machine head is connected, the blowing pipe (1) is fixed by the blowing pipe positioning and reciprocating device, and realizes reciprocating movement within a certain range; the specific production process is: the extruder produces a thick-walled pipe (20), which is cooled After being shaped, the first pulling device (5) performs the first axial stretching, and the heating device (6) heats the tube blank (20) that has undergone the first axial stretching to 110-150°C. The expansion and setting device (8) expands and sets the heated tube (20), and the cooling device (9) cools the expanded tube (20) for 15-30s, and the cooled tube (20) Enter the second traction device (10).
The method for preparing a biaxially stretched PVC pipe according to claim 1, wherein the blowing tube positioning and reciprocating device comprises a blowing tube support (2), a spring fixed end (3) and a spring (4) .
The method for preparing biaxially stretched PVC pipes according to claim 1, wherein the speed ratio of the first traction device (5) and the second traction device (10) is 1.1 to 3.
The method for preparing a biaxially stretched PVC pipe according to claim 1, wherein the expansion and setting device (8) includes a cylinder (11), a fixed template (12), a guide rod (13), and a movable The template (14), the shaping mold (15), the shaping mold (15) is fixedly installed on one side of the movable template (14), and the other side of the movable template (14) is fixedly connected with the cylinder piston (16). The air cylinder (11) is fixedly installed on the fixed template (12), the guide rod (13) penetrates the movable template (14) and the fixed template (12), and the expansion setting device (8) can realize linear reciprocating motion.
The method for preparing biaxially stretched PVC pipes according to claim 1, characterized in that the shaping die (15) is respectively provided with an expansion section (17) and a transition section (17) along the direction of movement of the tube blank (20). 18) and the shaping section (19), the length ratio of the expansion section (17), the transition section (18) and the shaping section (19) is 2:1:2, and the temperature of the expansion section (17) is set to 130-135 The temperature of the transition section (18) is set to 110-120°C, and the temperature of the shaping section (19) is set to 80-95°C.
The method for preparing a biaxially stretched PVC pipe according to claim 1, characterized in that the working process of the expansion setting device (8) is: after the tube blank (20) reaches the expansion setting device (8), it is shaped The mold (15) is closed and the tube (7) is inflated at the same time. After the tube (7) is full, the expansion pressure is maintained. At the same time, the tube (7) and the shaping mold (15) are moved forward synchronously with the tube blank (20). After moving and reaching a certain position, the expanded cloth tube (7) is deflated and the shaping mold (15) is opened. The expanded cloth pipe (7) and the shaping mold (15) quickly return to the starting position at the same time, and the expansion process is repeated.
The method for preparing a biaxially stretched PVC pipe according to claim 1, wherein the expansion pressure of the expansion setting device (8) is 0.2-0.5 MPa during operation.