CN102700108A - Coextruded mould of polrvinyl chloride and polymethylmethacrylate - Google Patents

Abstract

The invention provides a co-extrusion die of polyvinyl chloride and polymethyl methacrylate, which belongs to the field of extrusion die design and manufacturing, including a connector and subsequent die monomers, and the die monomers are sequentially provided with Divergent plate, diverter plate B5, diverter plate A, compression plate, die plate B, die plate A, the cavity in the connector and the mold monomer constitutes a flow channel for the material to enter and exit, and a core and a mold core are arranged in the flow channel. Insert, the connector has a polyvinyl chloride feed port, and the die plate B has a polymethyl methacrylate feed port; the flow channel includes a polyvinyl chloride flow channel and a polymethyl methacrylate Methyl acrylate flow channel, the polyvinyl chloride flow channel and polymethyl methacrylate flow channel converge in the die plate A, the confluence is the co-extrusion material confluence, and the co-extrusion material confluence is far from the die head The outlet of plate A is 18-22mm. The mold of the invention can make two kinds of materials with different characteristics compound together during the extrusion process, and the fusion interface is stable and uniform.

Description

A kind of polyvinyl chloride and polymethyl methacrylate co-extrusion die

technical field

The invention belongs to the field of extrusion die design and manufacture, and relates to the design and manufacture of a polyvinyl chloride and polymethyl methacrylate co-extrusion die.

Background technique

The production of modern plastic products has gradually developed from a single material to a composite material. So far, it has developed to composite materials such as plastic and rubber, metal materials, wood, fibers, inorganic materials or various plastics. Composite molding technology is characterized by its unique Excellent performance, widely used in construction, automobile, electronics and furniture industries.

Plastic co-extrusion processing technology is an extrusion composite molding technology that was applied in the early 1980s, and it has become one of the most advanced plastic molding processing methods in the contemporary era. The plastic co-extrusion process uses several extruders to supply different molten streams respectively, and the streams are merged and co-extruded in a compound head to obtain multi-layer composite products. It can make multiple layers of materials with different properties compound together during the extrusion process, so that the product has the excellent properties of several different materials and complements each other in terms of properties, so as to obtain performance and appearance with special requirements, such as anti-corrosion Oxidation, moisture resistance, moisture retention, thermoforming and thermal bonding capabilities, and mechanical properties such as strength, stiffness, and hardness. These multilayer composite materials with comprehensive properties have extremely wide application value in many fields. In addition, it can greatly reduce the cost of products, simplify the process, and reduce equipment investment. The compounding process does not use solvents and rarely produces three wastes. Therefore, co-extrusion technology has been used in the production of composite films, sheets, pipes, profiles and wires and cables.

The purpose of profile co-extrusion is mainly to extrude plastics of different properties to different parts of the same profile, so as to endow the profile with special functions or obtain the best performance and price ratio, diversify or multi-function the products, and improve product grades and reduce costs.

Since there are two kinds of melts in the co-extrusion die, their respective viscosities, flow velocities and pressures are not the same, it is easy to form irregular and uneven fusion interface; It is more complicated than general co-extrusion, and the interface fusion is difficult to control, so the uniform and stable interface fusion is the difficulty in the design of surface co-extrusion die structure

Contents of the invention

The purpose of the present invention is to provide a polyvinyl chloride and polymethyl methacrylate co-extrusion die, which can extrude materials with different properties to different parts of the same profile, and the interface fusion is uniform and stable.

The present invention provides a polyvinyl chloride and polymethyl methacrylate co-extrusion die, comprising a connector and subsequent mold monomers, the mold monomers are sequentially provided with a diverging plate, a splitter plate B, a splitter plate A, Compression plate, die head plate B, die head plate A, the cavity in the connecting head and the mold monomer constitute the flow channel for the material to enter and exit, the flow channel is provided with cores and inserts, and the connecting head is provided with poly Vinyl chloride feed port, polymethyl methacrylate feed port is opened on the die head plate B; the flow channel includes polyvinyl chloride flow channel and polymethyl methacrylate flow channel, the polyvinyl chloride The flow channel and the polymethyl methacrylate flow channel converge in the die plate A, and the confluence point is the confluence point of the co-extrusion material, and the confluence point of the co-extrusion material is 18-22mm away from the plane where the outlet on the die plate A is located .

Both the splitter plate A and the splitter plate B are provided with key grooves for assembling and supporting the mold core.

Dividing ribs are arranged in the flow channel.

The inlet size of the polyvinyl chloride flow channel on the compression plate is larger than the outlet size.

The mold also includes two sets of mold cells. The two groups of mold monomers share a polyvinyl chloride feed port, and the feed port is connected with two runners, and each runner supplies polyvinyl chloride to a mold monomer.

Effect of the present invention:

The polyvinyl chloride and polymethyl methacrylate co-extrusion die provided by the invention can make two kinds of materials with different characteristics compound together during the extrusion process, and the fusion interface is stable and uniform.

Through the design and manufacture of a new polyvinyl chloride and polymethyl methacrylate co-extrusion die, multiple extruders can simultaneously supply molten polyvinyl chloride and polymethyl methacrylate separately. Extrude two bundles of composite products, that is, simultaneously extrude two bundles of polyvinyl chloride and polymethyl methacrylate co-extruded profiles shown in Figure 1 on the same extrusion line, which is equivalent to the output of two conventional extrusion lines . It not only significantly improves production efficiency, reduces energy consumption, reduces investment in extrusion equipment, and greatly improves economic benefits, but also enables two materials with different characteristics to be combined with each other during the extrusion process, making the finished product It has the excellent characteristics of two different materials and complements each other in terms of characteristics. The main profile is used to make doors and windows, which not only insulates heat, keeps heat, saves energy, but also saves wood and steel. It is a profile that the country vigorously promotes. Polymethyl methacrylate is on the outside of the polyvinyl chloride profiled main material, that is, the part exposed to the sun, and has properties such as weather resistance, flame resistance, and impact resistance.

Description of drawings

Figure 1 Cross-sectional view of polyvinyl chloride and polymethyl methacrylate co-extruded profiles, in which 1-polyvinyl chloride 2-polymethyl methacrylate.

Fig. 2 is the front view of the mold of the present invention.

Fig. 3 is a top view of the mold of the present invention, wherein 12-runner A, 13-runner B.

Figure 4 is a cross-sectional view of A-A in Figure 3, where 1-die plate A, 2-die plate B, 3-compression plate, 4-manifold plate A, 5-manifold plate, B 6-divergent plate, 7-connection Head, 8-core, 9-insert, 10-polymethylmethacrylate supply port, 11-polyvinyl chloride supply port.

Fig. 5 is a front view of the compression plate.

Fig. 6 is a left view of the platen plate, wherein 14-polymethyl methacrylate flow channel, 15-polyvinyl chloride flow channel.

FIG. 7 is a front view of the die plate B. FIG.

Fig. 8 is a left view of the die plate B, wherein 14-polymethyl methacrylate flow channel, 15-polyvinyl chloride flow channel.

Fig. 9 Front view of die plate A.

Fig. 10 is a left view of the die plate A, wherein 15-polyvinyl chloride runner, 17-discharge port.

Fig. 11 is a partially enlarged view of part A in Fig. 10, where 14-polymethyl methacrylate runner, 16-coextrusion confluence.

Fig. 12 is a cross-sectional view of B-B in Fig. 9, wherein 14- is a polymethyl methacrylate flow channel.

the

Detailed ways

Below in conjunction with accompanying drawing 1-12, take polyvinyl chloride and polymethyl methacrylate co-extrusion die as an example, illustrate the design and manufacturing process of co-extrusion die, accompanying drawing 1 is exactly a kind of polyvinyl chloride and polymethacrylic acid Sectional view of methyl ester coextruded profiles. On the outside of the PVC fan body, the part exposed to the sun is covered with a weather-resistant, flame-resistant and impact-resistant polymethyl methacrylate (abbreviated code: PMMA, commonly known as plexiglass) layer with a molecular weight of 120,000 to 180,000. The thickness is generally 0.2 ~ 0.5mm. Polyvinyl chloride is a complex hollow special-shaped main material. The hollow can be used for heat insulation and heat preservation. In order to increase the strength, steel lining is added to make plastic steel doors and windows. It can replace wood and steel. It is a material actively promoted by the country. Polymethyl methacrylate is on the outside of the polyvinyl chloride profiled main material, that is, the part exposed to the sun, and has properties such as weather resistance, flame resistance, and impact resistance.

Determine the parameters according to the customer's technical contract and drawing requirements: preliminarily determine the compression ratio according to the empirical formula, generally 3 to 7, the compression ratio in this example is 4, initially determine the outlet clearance, and initially determine the length of the inlet cavity, the length of the shunt cavity, and the compression ratio. The length of the cavity and the length of the molding cavity are optimized and analyzed by simulation software to check whether the flow at the exit is balanced and the speed is consistent. Otherwise, the structural parameters of the mold must be adjusted to ensure that the melt at the exit of the die is evenly extruded.

Fig. 2 is exactly the structural diagram of polyvinyl chloride and polymethyl methacrylate co-extrusion die of the present invention.

The polyvinyl chloride and polymethyl methacrylate co-extrusion die includes the connector 7 and the following mold monomers, and the mold monomers are sequentially provided with a divergent plate 6, a diverter plate B5, a diverter plate A4, and a compression plate 3. Die head plate B2, die head plate A1, the cavity inside the connecting head 7 and the mold monomer constitutes a flow channel for the material to enter and exit, the flow channel is provided with a core 8 and an insert 9, and the connecting head 7 is A polyvinyl chloride feed port 11 is provided, and a polymethyl methacrylate feed port 10 is provided on the die plate B2; the flow path includes a polyvinyl chloride flow path 15 and a polymethyl methacrylate flow path 14. The polyvinyl chloride flow channel 15 and the polymethyl methacrylate flow channel 14 converge in the die plate A1, and the confluence is the co-extrusion material confluence 16, and the co-extrusion material confluence 16 is far from the die head The plane where the outlet 17 of the plate A1 is located has 18-22 mm, preferably 20 mm. The polyvinyl chloride feed port 11 of the mold is connected with the extruder through a flange, and the polymethyl methacrylate feed port 10 is connected with another extruder through a connecting hole, so that two extruders can simultaneously supply the extruder. The melted polyvinyl chloride and polymethyl methacrylate melts pass through their respective flow channels under the action of pressure. After being divided and compressed, they converge in the die plate A1. After further compression and shaping, they flow from the die The head plate A is slit-extruded to form a surface co-extruded plastic parison, and finally after cooling and shaping, a surface co-extruded plastic profile with a cross-sectional shape as shown in Figure 1 is formed.

Both the splitter plate A and the splitter plate B are provided with key grooves for assembling the support core 8 .

Dividing ribs are arranged in the flow channel.

The inlet size of the polyvinyl chloride flow channel on the compression plate 3 is larger than the outlet size. The melt is compressed to obtain sufficient density. The mating surface is also designed with threaded through holes and opening slots for assembly and disassembly. In the compression plate 3 of the present invention, a polymethyl methacrylate flow channel 14 is also designed on the outlet surface to diverge the molten polymethyl methacrylate from the die plate 2 .

The mold also includes two sets of mold cells. The two groups of mold monomers share the same polyvinyl chloride feed port 11, and the feed port 11 is connected with two runners A12 and B13, and each runner supplies polyvinyl chloride for one mold monomer. In this way, two bundles of polyvinyl chloride and polymethyl methacrylate surface co-extruded profiles shown in Figure 1 can be simultaneously extruded on the same extrusion line, which is equivalent to the output of two conventional extrusion lines.

The inlet structure of the connecting head 7 described in the present invention is determined according to the model of the customer’s extruder, the outlet cavity of the connecting head 7 is designed according to the shape, wall thickness, speed, and compression ratio of the main profile, and the outlet side of the connecting head 7 is matched Threaded holes are also designed on the surface to assemble the template on the right side.

The divergent plate 6 according to the present invention has the same inlet and outlet cavity as the outlet cavity of the connector 7, and the molten polyvinyl chloride plastic melt is preliminarily shunted through the core 8 tail cone, and the threaded through hole and opening groove are also designed on the mating surface , for assembly and disassembly.

The splitter plate A4 and the splitter plate B5 described in the present invention are designed with key grooves, which are used to assemble the support core 8, and a number of splitter ribs are designed in the cavity to divide the melt into several units with similar geometric characteristics for splitting, Stable molten plastic melt, threaded through holes and opening grooves are also designed on the mating surface for assembly and disassembly.

The gap area formed by the die plate B2, the die plate A1, the core 8 and the insert 9 in the present invention belongs to the forming section and is the most important area affecting the uniformity of the mold discharge, and the discharge gap must be uniform. Correspondingly designed threaded holes, through holes, counterbores and opening grooves are also designed on each mating surface for assembly and disassembly.

In addition to the above functions, the die plate B2 and die plate A1 of the present invention are also designed with a polymethyl methacrylate flow channel 14 (co-extrusion flow channel), and the die plate B2 is provided with polymethyl methacrylate. Ester feed port 10, the co-extruded polymethyl methacrylate flows out from the feed port in the die plate B2 through the polymethyl methacrylate flow channel 14 to the polymethyl methacrylate flow channel in the compression plate 3 14, and then through the polymethyl methacrylate flow channel 14 in the die plate B2 to flow and extrude. Then it is compressed and extruded through the polymethyl methacrylate flow channel 14 in the die plate A1, and merges with the polyvinyl chloride flow channel in the die plate A1. Extrusion junction 16 is 18-22mm away from the plane where outlet 17 on die plate A1 is located, preferably 20 mm.

In this embodiment, lifting holes, temperature measuring holes, and heating plate mounting holes are also designed around the mold (note: not shown in the structure diagram).

In this embodiment, each die plate cavity and die plate B2 co-extrusion flow channel are processed by slow wire cutting, compression plate 3 co-extrusion flow channel, die head plate B2 co-extrusion flow channel 1, die head plate A1 co-extrusion flow The channel is processed by a machining center, and the surface polishing is mainly performed by an extrusion honing machine. The surface roughness of each cavity is: Ra0.1.

In this embodiment, the connecting holes of each die plate and connecting head 7 are processed by CNC drilling machine. When the fitter assembles, the cavity is aligned, the gap is uniform, and the size meets the requirements of the drawing.

After the die head of this embodiment is assembled, it is molded and debugged on the extrusion production line, and the size and performance of the product are inspected. The results show that it fully meets the customer's requirements.

Claims (5)

1. A polyvinyl chloride and polymethyl methacrylate co-extrusion die, comprising a connector and subsequent die monomers, said die monomers are successively provided with divergent plate, splitter plate B, splitter plate A, compression plate, die plate B, and die plate A, the cavity in the connecting head and the mold monomer constitutes a flow channel for the material to enter and exit, and a core and an insert are arranged in the flow channel, and it is characterized in that: the connecting head There is a polyvinyl chloride feed port, and a polymethyl methacrylate feed port is opened on the die plate B; the flow channel includes a polyvinyl chloride flow channel and a polymethyl methacrylate flow channel, and the The polyvinyl chloride flow channel and the polymethyl methacrylate flow channel converge in the die plate A, and the confluence point is the confluence point of the co-extrusion material. 18-22mm. 2. The polyvinyl chloride and polymethyl methacrylate co-extrusion die according to claim 1, characterized in that: the splitter plate A and the splitter plate B are provided with key grooves for assembling and supporting the core. 3. The co-extrusion die of polyvinyl chloride and polymethyl methacrylate according to claim 2, characterized in that: said flow channel is provided with flow-distributing ribs. 4. The polyvinyl chloride and polymethyl methacrylate co-extrusion die according to claim 2 or 3, characterized in that: the inlet size of the polyvinyl chloride flow channel on the compression plate is larger than the outlet size. 5. The polyvinyl chloride and polymethyl methacrylate co-extrusion die according to claim 4, characterized in that: the die further comprises two sets of die monomers.

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