Resin molding apparatus and method for manufacturing resin molded article

Abstract

To improve the dispersibility of reinforcing fibers in a matrix resin by effectively removing impurities, etc., from the matrix resin and the reinforcing fibers contained in the matrix resin.SOLUTION: A plasticizing cylinder for plasticizing a base material resin and an injection cylinder for injecting a molten resin into a mold are connected to each other, a gas discharge nozzle is provided at a tip of the injection cylinder, and the plasticizing cylinder is provided with reinforcing continuous fiber supply means for supplying continuous reinforcing fibers from a vent opening of the plasticizing cylinder to the plasticizing cylinder and a plasma treatment unit for performing a plasma treatment on the reinforcing continuous fibers.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a novel resin molding apparatus and a method for manufacturing a resin molded product. [Background technology]

[0002] A widely known technique is to mix reinforcing fibers such as glass fiber or carbon fiber into a base resin to increase the strength of a resin molded product. For example, the following patent document proposes an injection molding machine that supplies continuous reinforcing fibers from a vent formed in the middle of a heating cylinder and mixes the reinforcing fibers into a molten resin to manufacture a resin molded product. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-166712 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the injection molding machines proposed in the above patent documents often leave impurities in the base resin and reinforcing fibers, and the reinforcing fibers are not sufficiently dispersed within the base resin, making it difficult to produce high-quality, strong, solid molded products. In response to this, the present invention aims to provide a resin molding apparatus for producing novel resin molded products that have significantly improved strength by improving the dispersibility of reinforcing fibers mixed into the base resin and removing impurities, and a method for producing resin molded products using this apparatus.

[0005] In order to solve the above problems, the present inventors analyzed and investigated conventional resin molding techniques, and found that there were three problems. First problem Dispersion of reinforcing fibers within the matrix resin When reinforcing fibers are mixed into molten resin during the resin molding process, the reinforcing fibers tend to orient in a certain direction, which can lead to a phenomenon known as agglomeration, where the fibers overlap, causing a decrease in strength. Second problem Adhesion between the base resin and reinforcing fibers Carbon fibers and the like are widely used as reinforcing fibers mixed into molten resins during resin molding. However, even if such fibers are manufactured as single strands, when they are sold commercially, their surfaces are coated with a thermosetting adhesive such as an epoxy resin, called a sizing agent, to prevent damage and make them easier for users to handle, and they are bundled together in units of several thousand and wound around a bobbin. However, because such sizing agents are thermosetting, they have poor adhesion to the thermoplastic resin matrix, reducing the adhesive strength at the interface. Third problem Reinforcing fibers cut during the manufacturing process In-line injection units, which are currently widely used to manufacture resin molded products, are equipped with a backflow prevention ring to prevent the molten resin from flowing back when it is injected into a mold. However, when the screw inside the cylinder is advanced to transfer the molten resin, this backflow prevention ring cuts the reinforcing fibers that have already been cut inside the cylinder into even shorter pieces than necessary. Therefore, the length of the reinforcing fibers contained in the manufactured molded product is shortened more than necessary, which reduces the strength.

[0006] In order to solve the above problems, the present inventors have proposed the following device and method. That is, claims 1 to 5 propose a resin molding device with a novel configuration that can solve the problems pointed out above. ●Claim 1 a vent opening for introducing continuous reinforcing fibers into the interior is formed on the upper surface of the peripheral wall intermediate portion; a plasticizing cylinder having a material discharge passage formed at its tip and a screw installed inside; The plasticizing cylinder is connected to an injection cylinder that is connected to the plasticizing cylinder through the material discharge path and has a gas discharge nozzle at its tip. the plasticizing cylinder is provided with a backflow prevention mechanism having a structure that prevents cutting of the reinforcing fibers when the flow of molten resin is interrupted during the injection process of the injection cylinder, a reinforcing fiber supply means that is disposed above the vent opening and that continuously supplies the reinforcing fibers, and a plasma treatment section that is disposed between the vent opening and the reinforcing fiber supply means and that performs plasma treatment on the reinforcing fibers, A resin raw material having a predetermined moisture content is supplied to the plasticizing cylinder, the gas discharge nozzle includes a resin injection port, a gas discharge port, and a filter structure; A resin molding device characterized in that heated molten resin is injected from the resin injection port toward a mold for molding, while moisture contained in the molten resin is gasified and exhausted from the gas discharge port, and the filter structure is configured to capture impurities contained in the heated molten resin and the moisture. In the present invention, the resin raw material may be thermoplastic resin pellets, resin powder, or any of these containing ultrafine fibrous materials (hereinafter referred to as "reinforcing short fibers"). ●Claim 2 In claim 1, The resin molding apparatus, wherein the resin raw material contains carbonated water, carbon dioxide gas, hydrocarbons, or organic solvents as subcritical reactants in place of or in addition to the water. In this invention, the resin raw material can be not only water, but also any substance that changes to a subcritical state when pressure and temperature are applied. Typical safe and easy-to-handle alternatives to water are carbonated water and carbon dioxide gas, but low-molecular hydrocarbons and organic solvents can also be used. FIG. 4A is a table showing examples of substances that can be used as subcritical reactants in the present invention. In the table, the critical conditions for water are a pressure of 218.3 atm and a temperature of 374.2°C. Carbon dioxide has a pressure of 72.8 atm and a temperature of 31.0°C. Methane, a hydrocarbon, has a pressure of 45.4 atm and a temperature of -82.6°C, and methanol, an organic solvent, has a pressure of 79.8 atm and a temperature of 239.6°C. All of these gases transition to a critical state at lower pressures and temperatures than water. From a safety standpoint, highly volatile gases are undesirable as subcritical reactants, but carbonated water, nonionic surfactants, and other substances that can be safely converted to a subcritical state can also be used, and the proportion of each substance contained in the resin raw material will vary depending on the substance. ●Claim 3 In claim 1 or 2, The resin molding device is provided with a laser processing section that irradiates the reinforcing fibers with a laser instead of the plasma processing section. ●Claim 4 In any one of claims 1 to 3, The backflow prevention mechanism is a resin molding device configured to close and open the material discharge path by controlling the forward and backward movement of the screw to insert the tip of the screw into a receiving port formed in the material discharge path formed at the tip of the plasticizing cylinder. ●Claim 5 In any one of claims 1 to 4, The plasticizing cylinder is provided with a screw having portions of different thicknesses, In the process of heating and melting the resin raw material, the resin molding device changes the moisture contained in the resin raw material heated and melted in the plasticizing cylinder to a state close to subcritical. Furthermore, claims 6 and 7 propose a resin molding method using a resin molding device with a novel configuration. ●Claim 6 A method for manufacturing a resin molded product using the resin molding apparatus according to any one of claims 1 to 5, a step of supplying a thermoplastic resin raw material having a predetermined moisture content into the plasticizing cylinder through a material inlet; feeding continuous reinforcing fibers into the plasticizing cylinder through the vent opening; a step of injecting the heated and melted resin raw material from a resin injection port of the gas ejection nozzle, while converting moisture contained in the heated and melted resin raw material into gas and evacuating it from a gas ejection port of the gas ejection nozzle; and capturing impurities contained in the molten resin and moisture. ●Claim 7 In claim 6, The method for producing a resin molded product, wherein the reinforcing fibers are thicker than the reinforcing short fibers. [Effects of the Invention]

[0007] According to the present invention, impurities and the like that tend to remain in the molten resin can be effectively removed by the gas discharge nozzle. Furthermore, a gas discharge nozzle is provided at the tip of the injection cylinder, and the molten resin is heated and pressurized to be injected into the mold, thereby increasing the fluidity of the molten resin. This in turn eliminates aggregation of the reinforcing short fibers contained in the base resin from the beginning and the reinforcing fibers supplied from the vent opening during the molding process, improving dispersion. Furthermore, impurities contained in the molten resin and water are physically captured by the gas emission nozzle before the molten resin is injected into the mold, and are also decomposed by the water in a near-subcritical state, so impurities can be effectively removed. Furthermore, the continuous reinforcing fibers are plasma-treated or laser-treated before being fed into the plasticizing cylinder to remove the sizing agent applied to the surface of the reinforcing fibers, thereby improving the adhesive bonding between the base resin and the reinforcing fibers. Furthermore, a backflow prevention mechanism is used that does not cut the mixed reinforcing fibers when transferring the molten resin from the plasticizing cylinder to the injection cylinder, so the reinforcing fibers contained in the resin molded product are not cut shorter than necessary, which would result in a decrease in strength. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a vertical cross-sectional view of a resin molding apparatus according to the present invention. [Figure 1A]FIG. 10 is a vertical cross-sectional view of a resin molding apparatus according to another embodiment of the present invention. [Figure 2] FIG. 2 is a schematic vertical cross-sectional view of a resin raw material containing reinforcing short fibers. [Figure 3] 1 is a flow diagram of a method for manufacturing a resin molded product according to the present invention. [Figure 4] 1 is a schematic longitudinal sectional structural view of a resin molded product to which the present invention is applied to a screw fastener. [Figure 4A] FIG. 1 illustrates an example of a subcritical reactant. [Figure 5] 1 is a photograph showing the appearance of a resin molded product, showing the results of a tensile strength test comparing the strength of a resin molded product produced by the method of the present invention with that of a resin molded product produced by a conventional method. [Figure 6] 1 is a graph showing tensile test data comparing the strength of a resin molded article produced by the method of the present invention with that produced by a conventional method. DETAILED DESCRIPTION OF THE INVENTION

[0009] As shown in Figure 1, the resin molding apparatus A according to the present invention is a so-called screw-plunger type apparatus, which combines a plasticizing cylinder B equipped with a screw 10 and an injection cylinder C equipped with a plunger 11. The injection cylinder C and a mold D can be connected or separated.

[0010] The plasticizing cylinder B is of the so-called DFFIM type (direct fiber injection molding) in which a vent opening 12 for introducing continuous reinforcing fibers L into the interior is formed on the upper surface of the middle part of the peripheral wall. An electric heating coil 13, which serves as a heating means, is wound around the peripheral wall, and is further covered with a heat insulating material 14. A material input hopper 15 (material input port) for storing resin raw material P (pellets) is provided at the base of the plasticizing cylinder B.

[0011] The screw 10 installed inside the plasticizing cylinder B plasticizes the resin raw material P heated by the heating means while transporting it forward. At its base, a motor device 16 for rotating the screw 10 and a hydraulic device 17 for moving the screw 10 forward and backward are connected. The shaft diameter and helical tooth shape of the screw 10 vary depending on the location.

[0012] The reinforcing fiber supply means 18 is disposed above the vent opening 12. In this example, a carbon bobbin 18a is provided around which reinforcing fiber L is continuously wound. The reinforcing fiber L may be, for example, carbon fiber or glass fiber, but is not limited to these.

[0013] The plasma treatment unit 19 is disposed in the fiber transfer path between the vent opening 12 and the reinforcing fiber supply means 18, and performs plasma treatment on the continuous reinforcing fibers L before they are supplied to the plasticizing cylinder B through the vent opening 12. The plasma treatment unit 19 is composed of a treatment chamber 19a through which the reinforcing fibers L are inserted, a plasma generator 19b, and a power supply unit 19c. This plasma treatment is performed at room temperature and pressure, and nitrogen or argon can be used as the gas. The plasma treatment improves hydrophilicity and removes sizing agents (epoxy resins) that bind the reinforcing fibers L together. The continuous reinforcing fibers L fed into the plasticizing cylinder B through the vent opening 12 are cut to an appropriate size in the plasticizing cylinder B and mixed into the molten resin. The inner wall of the plasticizing cylinder is designed with a structure that cuts the continuous cylinder fibers to an appropriate size.

[0014] FIG. 1A shows a resin molding apparatus A' according to another embodiment of the present invention. Unlike the resin molding device A shown in Figure 1, a laser device 19A is placed in the fiber transfer path of the reinforcing fiber supply means 18, and laser treatment is performed on the continuous reinforcing fiber L before it is supplied to the plasticizing cylinder B through the vent opening 12. The laser processing unit 19A is composed of a processing chamber 19a through which the reinforcing fibers L are inserted, a laser irradiation device 19d, and a power supply device 19c. This laser processing is performed at room temperature and normal pressure, and by irradiating the reinforcing fibers L with a laser, the sizing agent (epoxy resin) applied to the surface to converge the fibers is evaporated and decomposed and removed.

[0015] The backflow prevention mechanism 20 is intended to prevent the molten resin from flowing back into the plasticizing cylinder B when the molten resin accumulated in the resin reservoir of the injection cylinder C is injected toward the mold. The backflow prevention mechanism 20 of the novel structure is constructed by combining the tip 10a of the screw 10 and the receiving portion 23a of the material discharge path 23 formed between the tip 10a of the screw 10 and the plasticizing cylinder B. The tapered tip 10a of the screw 10 has a shape that corresponds to the receiving portion 23a, and by inserting and removing the tip 10a of the screw 10 into and from the receiving portion 23a formed at the tip of the plasticizing cylinder B, the flow path for the molten resin between the plasticizing cylinder B and the injection cylinder C is closed and opened. In other words, when the molten resin is transferred from the plasticizing cylinder B to the injection cylinder C, the tip 10a of the screw 10 is held so as to maintain a certain gap from the receiving section 23a, and when the injection cylinder C injects, the tip 10a of the screw 10 is inserted into the receiving section 23a and closed, thereby blocking the flow of the molten resin.However, even if the flow of the molten resin is blocked, the reinforcing fibers contained in the molten resin will not be cut, unlike a backflow prevention ring.

[0016] The backflow prevention mechanism 20 is not limited to this structure, but may have any structure as long as the tip of the screw 10 closes and opens the resin discharge port of the plasticizing cylinder B when the screw 10 of the plasticizing cylinder B moves forward and backward.

[0017] The injection cylinder C is connected to the plasticizing cylinder B through a resin discharge passage 23 via a backflow prevention mechanism 20, and is provided with a gas discharge nozzle 21 at its tip. An electric heating coil 13 is wound around the peripheral wall of the injection cylinder C, and the cylinder is further covered with a heat insulating material 14. The plunger 11 installed inside the injection cylinder C is used to pressurize and inject the resin inside the injection cylinder C, and a hydraulic device 17 is connected to its base to move the plunger 11 forward and backward.

[0018] The gas discharge nozzle 21 is provided with a material flow path (not shown) through which the molten resin passes, a resin discharge port 21a, and a gas discharge port 21b. Here, the material flow path has extremely thin branch paths (hairlines) with multiple inlets, and when the molten resin passes through the branch paths, the moisture contained in the molten resin is gasified and released from gas release port 21b. Also, the molten resin that has passed through the branch paths in this way is finally merged into one and injected from resin release port 21a, and this special structure changes the moisture contained in the molten resin to a state close to subcritical, but it is desirable to set the temperature of the gas release nozzle higher than that of the tip of the injection cylinder in order to induce the generation of subcriticality. In other words, the molten resin is heated and melted in the plasticizing cylinder B, sent to the injection cylinder C, and accumulated in the resin reservoir. When the molten resin is extruded by the hydraulic device 17, the pressure is suddenly increased as it passes through the narrow material flow path formed in the gas discharge nozzle 21, causing the water in the molten resin to change from water vapor to a near-subcritical state. To change the water to a near-subcritical state, the temperature must be raised above the carbonization temperature of the resin raw material, but as long as the molten resin contains water, the resin will not carbonize, and this water in a near-subcritical state significantly increases the fluidity of the molten resin. Furthermore, the moisture that has increased the fluidity of the molten resin in this way turns into gas when the molten resin passes through the shunt channel and is released from the gas release port 21b, running through the molten resin at high speed along the way. This action disperses the reinforcing fibers even if they aggregate within the molten resin, and impurities contained in the gas are captured by the extremely fine shunting channels as a filter, and are decomposed by the water in a near-subcritical state. Furthermore, the moisture contained in the molten resin becomes gas and passes through the molten resin at high speed, and then is released at high speed from the gas release port 21b, so it does not flow back into the injection cylinder C, and therefore the molded product does not foam. Due to these characteristics, the produced resin molded products are free of clumping of short reinforcing fibers and reinforcing fibers, and are evenly dispersed in three dimensions, resulting in high-strength molded products with no foaming.

[0019] Next, a method for manufacturing a resin molded product using the resin molding device A will be described. In one embodiment of this manufacturing method, resin pellets containing reinforcing short fibers are used as the resin raw material, and the method has the following features. The process includes the steps of supplying a resin raw material P containing reinforcing short fibers such as nanofibers and having a predetermined moisture content to the raw material inlet of the plasticizing cylinder B, supplying reinforcing fibers L such as continuous carbon fibers from a vent opening 12, changing the moisture in the molten resin to a state close to subcritical using an injection cylinder C including a gas discharge nozzle 21 and the gas discharge nozzle 21, and injecting the molten resin from the resin discharge port 21a of the gas discharge nozzle while discharging the moisture contained in the molten resin from the gas discharge port 21b of the gas discharge nozzle 21. Furthermore, the method shown in FIG. 3 includes step S8 of changing the water content in the molten resin to a state close to subcritical, but this step is not essential to the present invention, as it is sufficient to improve the fluidity of the molten resin without changing the water content to a state close to subcritical (see steps S1 to S10 in FIG. 3 for the above). Furthermore, pressurizing molten resin to bring the water to a state close to subcritical is a concept that includes subcritical and supercritical states, and it is sufficient that the water contained in the resin, when heated and pressurized, changes to properties close to those of subcritical water, which are not found in ordinary water vapor.

[0020] The production method using polypropylene as the resin raw material P will be further described. As shown in Figure 2, the resin raw material P is a pellet containing a mixture of a base material M and short reinforcing fibers S, and it maintains a certain moisture content. The short reinforcing fibers S are high-strength fibers with an average diameter of 100 nm and a length of approximately 800 nm, such as cellulose nanofibers or carbon nanofibers, and their moisture absorption is approximately 0.02%, which is roughly the same as the water absorption rate. Depending on the type of resin, if the resin raw material P is stored for a certain period of time, the moisture content will be approximately equal to the water absorption rate, so that the resin raw material P can be used without drying.

[0021] In the plasticizing cylinder B, the temperature and pressure are controlled for each section, and by rotating the screw 10, the resin raw material P stored in the hopper 15 is introduced into the cylinder and transported to the tip side, where various processes such as plasticization, venting (releasing miscellaneous gases), and the addition of reinforcing fibers L are carried out. The screw 10 may be rotated in accordance with the timing of transferring and filling the resin from the plasticizing cylinder B into the injection cylinder C. The backflow prevention mechanism 20 moves the screw 10 to the retracted position to open the screw, and at this time the plunger 11 of the injection cylinder C is gradually retracted in accordance with the filling of the resin, and during this retraction the feed speed of the continuous reinforcing fiber is synchronized with the screw rotation speed to perform the sizing removal process.

[0022] To explain in more detail, in the plasticizing cylinder B, in the region from the resin inlet 22 to the vent opening 12, the temperature is raised stepwise from 160°C to 280°C for plasticization and pressurization, and while plasticizing, the pressure is also raised stepwise to allow air to escape to the resin inlet 22. The temperature is controlled by controlling the electric heating coil 13, and the pressure is controlled in advance by controlling the shaft diameter and pitch of the screw 10. At the vent opening 12, the temperature is maintained at 200°C, while the pressure is reduced to prevent the kneaded, molten resin from ejecting. While miscellaneous gases such as volatile impurities, air, and moisture are exhausted from the vent opening 12, continuous reinforcing fibers L are introduced into the plasticizing cylinder B. The reinforcing fibers L may be made of the same material as the short reinforcing fibers S or a different material. Furthermore, from the viewpoint of strength, the reinforcing fibers L are preferably thicker than the short reinforcing fibers S, for example, with a diameter of 10 to 30 μm. Here, the continuous reinforcing fibers L have had a portion of the sizing agent removed by plasma treatment or laser irradiation treatment when introduced. After being kneaded with the resin raw material, the continuous reinforcing fibers L are repeatedly cut by the dull mage portion 10b formed at the tip of the shaft of the screw 10 as the screw 10 rotates, resulting in a length of, for example, approximately 2 mm. In the region ahead of the vent opening 12, the temperature is lowered to 180° C. to prevent carbonization of the resin, while the pressure is increased to prevent air from entering through the vent opening 12. When the transfer and filling of the resin from the plasticizing cylinder B to the injection cylinder C is completed, the screw 10 is advanced to close the backflow prevention mechanism 20.

[0023] On the other hand, the injection cylinder C has different temperature controls for the cylinder body and the gas discharge nozzle 21. That is, the cylinder body is set to 180°C to prevent carbonization of the resin, and the gas discharge nozzle 21 is set to 200°C to be suitable for releasing moisture. When injecting resin into mold D, plunger 11 is advanced, which forces the molten resin into gas discharge nozzle 21, applying sudden pressure to the gas discharge nozzle 21, causing the water contained in the molten resin to change to a state close to subcritical. The water thus brought to a near-subcritical state penetrates well into the gaps between the base resin, reinforcing fibers, and short reinforcing fibers, decomposing and dissolving any remaining sizing agent and impurities, thereby significantly improving the bonding and adhesion between the base resin and the reinforcing fibers and short reinforcing fibers. Thus, the molten resin containing the reinforcing fibers and reinforcing short fibers is accelerated and pressurized just before being injected into the mold D, that is, when passing through the gas emission nozzle 21, and at this time the moisture becomes a high-speed gas and is exhausted to the outside from the gas emission nozzle 21b.

[0024] As shown in Figure 3, the steps of the manufacturing method can be summarized as follows: The steps shown here are a chronological representation of the processing of the same resin raw material, and in reality, some steps are carried out in parallel at the same time. Step S1 is a process of putting resin raw material into a plasticizing cylinder. Step S2 is a process of plasticizing and pressurizing the resin raw material. Step S3 is a process of decompressing and venting the resin. Step S4 is a process of plasma treating the continuous reinforcing fibers. Step S5 is a process of feeding the plasma-treated continuous reinforcing fibers into a plasticizing cylinder. Step S6 is a process of pressurizing the molten resin. Step S7 is a process in which the molten resin is transferred from the plasticizing cylinder to the injection cylinder and filled in. After this process, the backflow prevention mechanism is closed. Step S8 is a process in which the molten resin is pressurized as it passes through the gas discharge nozzle, bringing the water in the resin into a state close to subcritical. Step S9 is a process of releasing moisture from the gas release nozzle. Step S10 is a process of injecting resin into the mold.

[0025] Finally, an example in which the resin molded product according to the present invention is applied to a screw-type molded product will be described. According to the present invention, resin pellets containing reinforcing short fibers are used as the resin raw material, and by mixing reinforcing fibers into these, a resin molded product X is obtained in which reinforcing fibers L and reinforcing short fibers S are dispersed within the matrix resin M, as shown in Figure 4. More specifically, while the reinforcing fibers L are dispersed mainly in the thicker parts of the molded product, the reinforcing short fibers S are dispersed uniformly throughout the molded product, including the finer details, as a result of the increased fluidity of the matrix resin. As a result, the molded product is extremely strong, with high bending and breaking resistance overall and with fine details that are also resistant to shattering.

[0026] In the above explanation, polypropylene has been used as an example of a type of resin, but the present invention can also be applied to thermoplastic resins such as polyethylene, ABS, acrylic, polyamide, polycarbonate, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), and polybutylene terephthalate.

[0027] Supported by test data Figure 5 shows the results of a comparison of the strength of molded products produced by the present invention and conventional methods. In this comparative example, the molded products were molded into dumbbell test pieces and subjected to a tensile test in which they were pulled at a constant speed. All dumbbell test pieces used PP as the base resin and contained approximately 1% cellulose nanofiber as short reinforcing fibers. S0 shows the appearance of the dumbbell test piece before tensioning, S1 shows a dumbbell test piece manufactured by a conventional method that was subjected to a tensile test, and S2 shows a dumbbell test piece manufactured by the method of the present invention that was subjected to a tensile test. As is clear from comparing S1 and S2, S1 broke linearly with only a slight stretch in the middle, whereas S2 broke with a significant stretch in the middle, with the middle branching into multiple branches, clearly showing an increase in tensile strength. Therefore, it was confirmed from the appearance that the manufacturing method of the present invention significantly increased the strength of resin molded products compared to conventional methods. FIG. 6 shows test data from the tensile test of the dumbbell test piece, with the vertical axis representing the pressure applied during the tensile test (MPa) and the horizontal axis representing the elongated length (mm). S2 barely elongates even when the pressure is increased at first, but when further pressure is applied, it reaches a peak value and then withstands a pressure of 1400 MPa and does not break even when stretched beyond 30 mm. In contrast, S1 elongates slowly as the applied pressure increases, and breaks before reaching 12 mm. From this test data, it is clear that the resin molded article produced by the method of the present invention is modified to have a significantly improved mechanical strength. [Explanation of symbols]

[0028] A Resin molding equipment B. Plasticizing cylinder C Injection cylinder M Base material resin L Reinforcement fiber S Reinforced short fiber 12 Vent opening 18 Reinforcing fiber supply means 19 Plasma processing section 19A Laser Device 20 Backflow prevention mechanism (10a,23a) 21 Gas discharge nozzle 21a Resin outlet 21b Gas outlet 23 Material release path

Claims

1. a vent opening for introducing continuous reinforcing fibers into the interior is formed on the upper surface of the peripheral wall intermediate portion; a plasticizing cylinder having a material discharge passage formed at its tip and a screw installed inside; The plasticizing cylinder is connected to the material discharge passage, and a gas discharge nozzle is provided at the tip of the cylinder. The structure is connected to an injection cylinder equipped with The plasticizing cylinder is a backflow prevention mechanism having a structure that does not cut the reinforcing fibers even when the flow of molten resin is blocked during the injection process of the injection cylinder; a reinforcing fiber supply means disposed above the vent opening and configured to continuously supply the reinforcing fibers; a plasma treatment unit disposed between the vent opening and the reinforcing fiber supply means, for subjecting the reinforcing fibers to a plasma treatment; A resin raw material containing water at a predetermined ratio is supplied to the plasticizing cylinder, the gas discharge nozzle is provided with a resin injection port and a gas discharge port, A resin molding device characterized in that heated molten resin is injected from the resin injection port toward a mold for molding, while moisture contained in the molten resin is gasified and exhausted from the gas discharge port, and the gas discharge nozzle is configured to capture impurities contained in the heated molten resin and the moisture.

2. In claim 1, The resin molding apparatus, wherein the resin raw material contains carbonated water, carbon dioxide gas, hydrocarbons, or organic solvents as subcritical reactants in place of or in addition to the water.

3. In claim 1 or 2, The resin molding device is provided with a laser processing section, instead of the plasma processing section, that irradiates the reinforcing fibers with a laser.

4. In any one of claims 1 to 3, The backflow prevention mechanism is a resin molding device configured to close and open the material discharge path by inserting the tip of the screw into a receiving port formed in the material discharge path formed at the tip of the plasticizing cylinder through the forward and backward movement of the screw.

5. In any one of claims 1 to 4, The plasticizing cylinder is equipped with a screw having portions of different thicknesses, so that during the process of heating and melting the resin raw material, the moisture contained in the resin raw material heated and melted within the plasticizing cylinder is changed to a state close to subcritical. This is a resin molding device.

6. A method for manufacturing a resin molded product using the resin molding apparatus according to any one of claims 1 to 5, a step of supplying a thermoplastic resin raw material having a predetermined moisture content into the plasticizing cylinder through a material inlet; feeding continuous reinforcing fibers into the plasticizing cylinder through the vent opening; a step of injecting the heated and melted resin raw material from a resin injection port of the gas ejection nozzle, while converting moisture contained in the heated and melted resin raw material into gas and evacuating it from a gas ejection port of the gas ejection nozzle; and capturing impurities contained in the molten resin and moisture.

7. In claim 6, The method for producing a resin molded product, wherein the reinforcing fibers are thicker than the reinforcing short fibers.

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