Continuous fiber reinforced wood-plastic straight runner co-extrusion device and use method

Abstract

The invention discloses a continuous fiber reinforced wood-plastic straight runner co-extrusion device and a use method, and relates to the field of wood fiber material preparation. The problems that in the prior art, the mechanical property of a plate is lost due to runner bending, continuous fibers need to be pretreated before extrusion forming, and the working procedure is tedious are solved. The extrusion side of an extruder is connected with a first leading-in mold, continuous fibers enter the first leading-in mold, a dipping mold and a second leading-in mold are sequentially connected with the first leading-in mold, dipping treatment is completed when the continuous fibers pass through the dipping mold, and the extrusion side of a co-extruder is connected with the dipping mold. Preparing plant fiber / polymer composite material master batches; winding the continuous fiber around a lead frame and then passing through a combining mold; and heating the extruder and the co-extruder, putting the plant fiber / polymer composite material master batch into the extruder after a set temperature is reached, putting the impregnated material into the co-extruder, and starting to extrude. The method is used for preparing the wood-plastic plate.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of wood fiber materials, and in particular to a continuous fiber reinforced wood-plastic straight flow channel co-extrusion device and a use method thereof. Background Art

[0002] Wood-plastic composite materials are composite materials made of thermoplastic plastics (polyethylene, polypropylene, polyvinyl chloride and other high molecular polymers) as the matrix and biomass fibers (wood fibers, straw, flax fibers, etc.) as reinforcing materials, mixed in a certain proportion and prepared by extrusion, injection molding or hot pressing. On the one hand, the filling of biomass fibers can improve the mechanical properties of the polymer, and on the other hand, the coating of the polymer matrix can protect the biomass fibers from direct contact with the external environment and fiber damage. Wood-plastic composite materials have a wide range of raw materials and are inexpensive. They have both the beautiful texture and processability of wood and the reusability of thermoplastic polymers.

[0003] Wood-plastic composites can make full use of wood processing residues and waste plastics, which has positive significance for alleviating the shortage of forest resources and the treatment of waste plastics. In addition, wood-plastic composites also have excellent water resistance and a long service life, so wood-plastic composites are widely used in floor laying, interior decoration, automotive interior and other fields. However, due to the interface incompatibility between polar biomass fibers and non-polar plastic matrix in wood-plastic composites and the lack of strength of the matrix itself, the mechanical strength of wood-plastic composites is low, making it difficult to apply wood-plastic composites to load-bearing structural materials. Therefore, how to improve the mechanical properties of wood-plastic composites on a large scale and efficiently and realize their engineering applications in load-bearing structural materials still needs further exploration and research.

[0004] The main methods for improving the mechanical properties of wood-plastic composites include adding interfacial compatibilizers, wood powder modification, matrix modification, and additional addition of reinforcing fibers. The addition of reinforcing fibers can improve the mechanical properties of wood-plastic composites, and the reinforcing effect changes with the changes in fiber type and fiber content. According to the fiber size, the reinforcing fibers can be divided into short fibers and continuous fibers. The addition of a small amount of short fibers can improve the mechanical properties of wood-plastic to a certain extent, but when the fiber addition amount is high, fiber agglomeration will occur to produce stress concentration points, which will lead to a decrease in the performance of the composite material. In contrast, the addition of continuous fibers can effectively avoid fiber agglomeration and obtain better reinforcement effects. At the same time, continuous fibers have the advantage of being woven and processed. In addition, the size of continuous fibers is much larger than the critical length of the fibers, which is conducive to giving full play to the mechanical advantages of the fibers themselves.

[0005] However, the continuous fiber reinforced wood plastic products popular in the market today have curved mold runners due to the need for continuous fiber embedding during the preparation process. For example, the patent number is CN106065194A, and the patent name is an invention patent for a continuous fiber reinforced wood plastic composite material and its preparation method. Figure 1 , Figure 1 The direction of the arrow in the figure is the extrusion direction of the WPC melt, which is bent. This bent extrusion method takes into account the fluidity of the WPC melt and ensures that the melt passes smoothly through the curved flow channel. Measures such as increasing lubrication and increasing the plastic content are taken, which greatly weakens the mechanical strength of the WPC product: There are two reasons why the curved flow channel reduces the performance of WPC: 1. It is necessary to add excessive lubricants or increase the plastic content to ensure the fluidity of the WPC melt, which will lead to a decrease in the strength of the WPC product. 2. The curved flow channel will cause the WPC melt to flow poorly at the bend of the flow channel, causing excessive pressure here, forming a high temperature and high pressure environment; and wood powder is very easy to degrade under high temperature and high pressure, which is also an important factor leading to the decrease in the strength of WPC products.

[0006] The flow direction of the wood-plastic melt in a curved flow channel will change at the bend, which will destroy the original structural uniformity of the wood-plastic melt and further damage the mechanical properties of the wood-plastic composite material. On the other hand, in order to improve the interface bonding between the continuous fiber and the wood-plastic matrix, the continuous fiber is usually required to be pre-impregnated before use, and the conventional pre-impregnation operation is cumbersome and has specific requirements for the impregnation equipment.

[0007] In summary, in the existing continuous fiber reinforced wood-plastic composite extrusion process, the mechanical properties of the board are lost due to the bending of the flow channel and the continuous fiber needs to be pretreated before extrusion molding, resulting in cumbersome procedures. Summary of the invention

[0008] The purpose of the present invention is to solve the problems of loss of mechanical properties of the board due to flow channel bending during the extrusion process of the existing continuous fiber reinforced wood-plastic composite material and the need to pretreat the continuous fiber before extrusion molding, resulting in cumbersome procedures, and further provide a continuous fiber reinforced wood-plastic straight flow channel co-extrusion device and a use method.

[0009] The technical solution of the present invention is:

[0010] A continuous fiber reinforced wood plastic straight flow channel co-extrusion device comprises an extruder and a co-extruder, and also comprises continuous fiber, a first introduction die, an impregnation die and a second introduction die. The extrusion side of the extruder is connected with the first introduction die, the continuous fiber enters the first introduction die, the impregnation die and the second introduction die are connected with the first introduction die in sequence, and the continuous fiber completes the impregnation treatment when passing through the impregnation die. The extrusion side of the co-extruder is connected with the impregnation die, and the wood plastic melt in the extruder is extruded in a straight line after passing through the first introduction die, the impregnation die and the second introduction die.

[0011] Furthermore, the first introduction mold, the impregnation mold and the second introduction mold are provided with continuous fiber channels that are interconnected.

[0012] Preferably, the distance between the continuous fiber channels along the centerline tapers.

[0013] Furthermore, the impregnation mold is provided with an impregnation material feeding hole.

[0014] Furthermore, it also includes a dipping material bin, which is installed on the output side of the co-extruder and connected to the dipping material feeding hole on the dipping mold.

[0015] Furthermore, it also includes a wire rack, which is installed on the upper and lower sides of a combined mold consisting of a first introduction mold, a dipping mold and a second introduction mold.

[0016] Preferably, a plurality of conductor rollers are respectively provided on the upper end and the lower end of the conductor rack.

[0017] The present invention also provides a method for using a continuous fiber reinforced wood-plastic straight flow channel co-extrusion device, which comprises the following steps:

[0018] Step 1: drying the plant fibers and thermoplastic polymer particles;

[0019] Step 2: Put the plant fiber, thermoplastic polymer particles, lubricant and coupling agent into a high-speed mixer and mix them evenly, wherein the plant fiber content is 60-80%, the polymer content is 35-15%, and the auxiliary agent content is 5%;

[0020] Step 3: pelletizing the material obtained in step 2 through a twin-screw extruder, and after cooling, pulverizing it in a pulverizer to obtain a plant fiber / polymer composite material masterbatch;

[0021] Step 4: Pass the continuous fiber around the lead frame and through the bonding die;

[0022] Step 5: Heat up the extruder and the co-extruder. After reaching the set temperature, put the plant fiber / polymer composite masterbatch into the extruder, put the impregnated material into the co-extruder and start extrusion.

[0023] Furthermore, the granulation process in step 3 is as follows: the mixed material is put into a twin-screw extruder, and is combined into a composite material after melt blending, and the heating range is 150° C.-190° C. The screw speed is 50-70 rpm, and the feeding speed is 5-15 rpm.

[0024] Furthermore, the continuous fiber in step 4 is basalt fiber, glass fiber, carbon fiber, aramid fiber, cotton fiber or hemp fiber.

[0025] Compared with the prior art, the present invention has the following effects:

[0026] 1. The present invention arranges the extruder 7, the first introduction mold 4, the impregnation mold 3 and the second introduction mold 2 in a straight line, so that the wood-plastic melt in the preparation process of continuous fiber reinforced wood-plastic can flow straightly. The straight flow has a certain directional effect on the wood powder. The wood powder can be arranged along the basic direction during the extrusion process. The normal flow of the wood-plastic melt can be ensured without adding excessive lubricants or increasing the content of plastics, thereby effectively improving the mechanical strength of the wood-plastic composite product.

[0027] 2. The straight flow of the wood-plastic melt of the present invention can avoid the problem of weakened board performance and non-uniform board uniformity (mainly referring to the wood powder accumulation part and non-accumulation part) caused by the bending behavior during the flow process (because the accumulation of wood powder will cause excessive pressure here, forming a high temperature and high pressure environment; and wood powder is very easy to degrade under high temperature and high pressure). 3. The continuous fiber impregnation process of the device is realized simultaneously during the extrusion process of the wood-plastic composite material, without the need for a separate impregnation device to impregnate the fibers in advance. The impregnation material becomes a molten state in the co-extruder and is injected into the impregnation tank of the impregnation mold through the feed hole. The impregnation tank is connected to the continuous fiber introduction pipe, so that the impregnation liquid can be filled in the pipe to achieve the effect of fully impregnating the fibers.

[0028] 4. The discharge hole of the present invention located on the other side of the impregnation mold (communicated with the prepreg hole 9, Figure 2 The middle impregnation mold 3 is connected to the outside world, and the excess impregnation liquid flows out under the action of pressure, so that the impregnation liquid can be recycled and reused.

[0029] 5. In the wood-plastic composite board produced by this device, the position of the continuous fiber in the finished product is controllable, generally located on the upper and lower surfaces of the finished product (the continuous fiber in the prior art is generally located in the middle of the wood-plastic board), which has a better enhancement performance in mechanical properties, especially in bending properties. For example: the bending strength of the wood-plastic composite material reinforced with continuous glass fiber is increased by 47.3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1It is a structural schematic diagram of a continuous fiber reinforced wood-plastic composite material preparation device in the prior art;

[0031] Figure 2 It is a front view of the present invention;

[0032] Figure 3 yes Figure 2 A top view of

[0033] Figure 4 1 is a schematic diagram of the overall structure of the extruded wood-plastic profile of the present invention; (the lead frame 11 is removed in this figure).

[0034] Figure 5 It is a cross-sectional schematic diagram of the combined mold;

[0035] Figure 6 The figure is a schematic diagram of a cross section of a wood-plastic board that can be processed by the continuous fiber reinforced wood-plastic straight flow channel co-extrusion device of the present invention. In addition, the position of the fiber of the wood-plastic board prepared by the co-extrusion device of the present invention in the wood-plastic product has the advantages of being designable and controllable. In particular, by adjusting the position of the fiber outlet in the mold, the fiber can be placed at any position in the wood-plastic cross section.

[0036] Figure 7 It is a schematic diagram of the co-extruder 5 and the impregnation die 3 of the present invention.

[0037] Figure 8 It is a schematic cross-sectional view of the internal flow channel of the impregnation mold 3 of the present invention.

[0038] The following are marked in the figure:

[0039] 1. continuous fiber reinforced wood plastic board, 2. second introduction mold, 3. impregnation mold, 4. first introduction mold, 5. co-extruder, 6. continuous fiber, 7. extruder, 8. continuous fiber channel, 9. impregnation material feeding hole, 10. impregnation material silo, 11. wire rack, 12. wire roller. DETAILED DESCRIPTION

[0040] Specific implementation method 1: Combination Figures 2 to 8 This embodiment is described. This embodiment includes an extruder 7 and a co-extruder 5. It also includes a continuous fiber 6, a first introduction die 4, an impregnation die 3, and a second introduction die 2.

[0041] The extrusion side of the extruder 7 is connected to the first introduction mold 4, the continuous fiber 6 enters the first introduction mold 4, the impregnation mold 3 and the second introduction mold 2 are connected to the first introduction mold 4 in sequence, and the continuous fiber 6 completes the impregnation treatment when passing through the impregnation mold 3, the extrusion side of the co-extruder 5 is connected to the impregnation mold 3, and the wood-plastic melt in the extruder 7 passes through the first introduction mold 4, the impregnation mold 3 and the second introduction mold 2 and is extruded in a straight line.

[0042] The present invention can realize a continuous fiber filling method in a straight flow channel, thereby avoiding the performance loss of the wood-plastic composite material caused by the bending of the flow channel. In addition, for the impregnation of continuous fibers, the present invention can realize an integrated process of impregnation and extrusion, thereby eliminating the pretreatment process of continuous fibers in conventional methods, thereby reducing costs and simplifying operations.

[0043] The fibers in the wood-plastic composite board produced by the present invention are embedded near the upper and lower surfaces of the board. When subjected to external force, the force can be transmitted to the continuous fibers more quickly, and the fiber reinforcement effect can be fully exerted before the board fails. The bending strength of the wood-plastic composite material reinforced with continuous glass fibers is increased by 47.3%.

[0044] Specific implementation method 2: Combination Figure 5 The present embodiment is described. In the present embodiment, the first introduction mold 4, the impregnation mold 3 and the second introduction mold 2 are provided with continuous fiber channels 8 that are interconnected.

[0045] With such arrangement, the continuous fiber channel 8 in this embodiment can ensure continuous and smooth transportation of the fibers. Other components and connection relationships are the same as those in the first embodiment.

[0046] Specific implementation method three: Combination Figure 5 To illustrate this embodiment, the distance of the continuous fiber channel 8 along the center line of this embodiment gradually decreases. This arrangement facilitates the gradual transition to the upper and lower parts of the board during the fiber conveying process. Other components and connection relationships are the same as those of the specific embodiment 1 or 2.

[0047] Specific implementation method four: Combination Figure 5 To explain this embodiment, the impregnation mold 3 of this embodiment is provided with an impregnation material feeding hole 9. Such a configuration facilitates the introduction of the impregnation liquid into the impregnation mold 3, so that the continuous fibers 6 are impregnated during the conveying process, omitting the impregnation process in the prior art, thereby improving the efficiency of the board preparation. The other components and connection relationships are the same as those of the first, second or third embodiments.

[0048] Specific implementation method five: Combination Figure 7 To explain this embodiment, this embodiment further comprises a dipping material silo 10 , which is installed at the output side of the co-extruder 5 and connected to the dipping material feed hole 9 on the dipping die 3 .

[0049] Such arrangement facilitates continuous supply of impregnation material to the continuous fibers 6, thereby ensuring the impregnation effect of the continuous fibers 6. Other components and connection relationships are the same as those of the first, second, third or fourth specific embodiments.

[0050] Specific implementation method six: Combination Figure 2To explain this embodiment, this embodiment further includes a lead frame 11 , which is installed on the upper and lower sides of the combined mold composed of the first introduction mold 4 , the impregnation mold 3 and the second introduction mold 2 .

[0051] In this way, the continuous fiber reinforced wood-plastic straight flow channel co-extrusion device of this embodiment, the fiber introduction mold (first introduction mold 4, second introduction mold 2) and the fiber impregnation mold (impregnation mold 3) together constitute a combination mold, the fiber enters the mold through the first introduction mold 4, and passes through the impregnation mold 3 containing the impregnation liquid, and then the second introduction mold 2 completes the combination between the impregnated continuous fiber and the wood-plastic matrix. Other components and connection relationships are the same as any one of the specific embodiments one to five.

[0052] Specific implementation method seven: Combination Figure 2 To explain this embodiment, a plurality of guide rollers 12 are respectively provided on the upper and lower ends of the guide frame 11 of this embodiment. Such a configuration facilitates the guidance of the input of the continuous fiber 6 and prevents the continuous fiber 6 from being knotted during the conveying process, thereby causing the continuous fiber channel 8 to be blocked. The other components and connection relationships are the same as any one of the specific embodiments 1 to 6.

[0053] Specific implementation method eight: Combination Figures 2 to 8 This embodiment describes a method for using a continuous fiber reinforced wood-plastic straight flow channel co-extrusion device, which includes the following steps:

[0054] Step 1: drying the plant fibers and thermoplastic polymer particles;

[0055] Step 2: Put the plant fiber, thermoplastic polymer particles, lubricant and coupling agent into a high-speed mixer and mix them evenly, wherein the plant fiber content is 60-80%, the polymer content is 35-15%, and the auxiliary agent content is 5%;

[0056] Step 3: pelletizing the material obtained in step 2 through a twin-screw extruder, and after cooling, pulverizing it in a pulverizer to obtain a plant fiber / polymer composite material masterbatch;

[0057] Step 4: passing the continuous fiber around the conductor frame 11 and passing through the bonding mold;

[0058] Step 5: The extruder 7 and the co-extruder 5 are heated up. After reaching the set temperature, the plant fiber / polymer composite material masterbatch is put into the extruder 7, and the impregnated material is put into the co-extruder 5 and starts extrusion.

[0059] In this way, the cross section of the continuous fiber reinforced wood plastic board prepared by the continuous fiber reinforced wood plastic straight flow channel co-extrusion device and preparation method of the present invention is as follows: Figure 6The continuous fiber reinforced wood plastic board is composed of a shell layer, a core layer, and continuous fibers close to the upper and lower surfaces. Other components and connection relationships are the same as any one of the specific embodiments 1 to 7.

[0060] Specific implementation method nine: Combination Figures 2 to 8 To illustrate this embodiment, the granulation process in step 3 of this embodiment is as follows: the mixed material is put into a twin-screw extruder, and after melt blending, it is combined into a composite material, and the heating interval is 150°C-190°C. The screw speed is 50-70rpm, and the feeding speed is 5-15rpm. Such an arrangement can ensure that the wood powder and the polymer are blended uniformly during the granulation process, and the granulation process is smooth. The other components and connection relationships are the same as any one of the specific embodiments one to eight.

[0061] Specific implementation method ten: Combination Figures 2 to 8 To illustrate this embodiment, the continuous fiber in step 4 of this embodiment is basalt fiber, glass fiber, carbon fiber, aramid fiber, cotton fiber or hemp fiber. This arrangement can give full play to the mechanical advantages of the fiber itself. The other components and connection relationships are the same as any one of the specific embodiments 1 to 9.

[0062] Combination Figures 2 to 8 The working principle of the present invention is described:

[0063] Step 1: drying the plant fiber and the thermoplastic polymer particles; wherein the plant fiber is wood powder, bamboo powder or straw powder, and the thermoplastic polymer particles are polyethylene, polypropylene or polystyrene;

[0064] Step 2: Put the plant fiber, thermoplastic polymer particles, lubricant and coupling agent into a high-speed mixer and mix them evenly, wherein the plant fiber content is 60-80%, the polymer content is 35-15%, and the auxiliary agent content is 5%;

[0065] The auxiliary agent is maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, an anti-aging agent or a lubricant;

[0066] Step 3: pelletizing the material obtained in step 2 through a twin-screw extruder, and after cooling, pulverizing it in a pulverizer to obtain a plant fiber / polymer composite material masterbatch;

[0067] Step 4: passing the continuous fiber around the conductor frame 11 and passing through a combining mold; wherein the number of continuous fiber channels in the combining mold is 10-50;

[0068] Step 5: heating the extruder 7 and the co-extruder 5, and after reaching the set temperature, putting the plant fiber / polymer composite material masterbatch into the extruder 7, and putting the impregnated material into the co-extruder 5 and starting extrusion;

[0069] Wherein, the impregnating material is ethylene-vinyl acetate copolymer, polyurethane, epoxy resin, etc.; the heating range of the extruder 7 is 150-180°C; the heating range of the co-extruder 5 is 150-200°C.

[0070] In the use method of the present invention, the continuous fibers do not need to be impregnated in advance, and the impregnation is completed during the extrusion process, thereby reducing the complexity of the operation.

[0071] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A continuous fiber reinforced wood plastic straight flow channel co-extrusion device, comprising an extruder (7) and a co-extruder (5), characterized in that: It also includes a continuous fiber (6), a first introduction mold (4), an impregnation mold (3) and a second introduction mold (2), The extrusion side of the extruder (7) is connected to the first introduction die (4), the continuous fiber (6) enters the first introduction die (4), the impregnation die (3) and the second introduction die (2) are connected to the first introduction die (4) in sequence, and the continuous fiber (6) completes the impregnation treatment when passing through the impregnation die (3), the extrusion side of the co-extruder (5) is connected to the impregnation die (3), and the wood-plastic melt in the extruder (7) passes through the first introduction die (4), the impregnation die (3) and the second introduction die (2) and is extruded in a straight line.

2. A continuous fiber reinforced wood plastic straight flow channel co-extrusion device according to claim 1, characterized in that: The first introduction mold (4), the impregnation mold (3) and the second introduction mold (2) are provided with continuous fiber channels (8) that are interconnected.

3. A continuous fiber reinforced wood plastic straight flow channel co-extrusion device according to claim 2, characterized in that: The distance between the continuous fiber channels (8) along the center line gradually decreases.

4. A continuous fiber reinforced wood plastic straight flow channel co-extrusion device according to claim 1 or 3, characterized in that: The impregnation mold (3) is provided with an impregnation material feeding hole (9).

5. The continuous fiber reinforced wood plastic straight flow channel co-extrusion device according to claim 4, characterized in that: The invention also comprises a dipping material silo (10), which is installed on the output side of the co-extruder (5) and connected to a dipping material feed hole (9) on the dipping die (3).

6. A continuous fiber reinforced wood plastic straight flow channel co-extrusion device according to claim 5, characterized in that: It also includes a wire frame (11), which is installed on the upper and lower sides of a combined mold consisting of a first introduction mold (4), an impregnation mold (3) and a second introduction mold (2).

7. A continuous fiber reinforced wood plastic straight flow channel co-extrusion device according to claim 6, characterized in that: A plurality of conductor rollers (12) are respectively arranged on the upper end and the lower end of the conductor frame (11).

8. A method for using the continuous fiber reinforced wood plastic straight flow channel co-extrusion device according to any one of claims 1 to 7, characterized in that: It includes the following steps: Step 1: drying the plant fibers and thermoplastic polymer particles; Step 2: Put the plant fiber, thermoplastic polymer particles, lubricant and coupling agent into a high-speed mixer and mix them evenly, wherein the plant fiber content is 60-80%, the polymer content is 35-15%, and the auxiliary agent content is 5%; Step 3: pelletizing the material obtained in step 2 through a twin-screw extruder, and obtaining a plant fiber / polymer composite masterbatch after cooling; Step 4: passing the continuous fiber around the conductor frame (11) and then passing through a bonding die; Step 5: The extruder (7) and the co-extruder (5) are heated up, and after reaching the set temperature, the plant fiber / polymer composite material masterbatch is put into the extruder (7), and the impregnated material is put into the co-extruder (5) and starts extrusion.

9. The method for using the continuous fiber reinforced wood plastic straight flow channel co-extrusion device according to claim 8, characterized in that: The granulation process in step 3 is as follows: the mixed material is put into a twin-screw extruder, and is combined into a composite material after melt blending, and the heating range is 150° C.-190° C. The screw speed is 50-70 rpm, and the feeding speed is 5-15 rpm.

10. The method for using the continuous fiber reinforced wood plastic straight flow channel co-extrusion device according to claim 9, characterized in that: The continuous fiber in step 4 is basalt fiber, glass fiber, carbon fiber, aramid fiber or hemp fiber.

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