JP6300997B1 - Molding method of reinforced fiber-containing resin molded product - Google Patents

Abstract

The present invention provides a method capable of appropriately distributing and mixing reinforcing fibers in a resin material to form a reinforcing fiber-containing resin molded article having good quality. A melting promoting portion is provided between a front end of a flight portion 25 of a screw 21 in a metering zone C and a backflow preventing valve portion 51 of a distribution / mixing backflow preventing valve 27. The range set to the maximum temperature of the heating cylinder 20 is set to 20 to 140 ° C. higher than the melting point of the resin material. In the heating cylinder 20 of the injection apparatus 2, the screw 21 is rotated at 40 to 120 revolutions / minute, the molding material is sent from the flight part 25 of the screw 21 to the melting promoting part 26, and the resin material is sufficiently melted. The material is sent to the distribution / mixing backflow prevention valve 27 to distribute and mix the reinforcing fibers of the resin material, and further sent to the front of the heating cylinder 20 to store a predetermined amount of molding material. The back pressure of the screw 21 at this time is set to 0 to 5 MPa. [Selection] Figure 1

Description

  The present invention relates to a method for molding a reinforced fiber-containing resin molded product, and in particular, an injection including a heating cylinder, a screw fitted into the heating cylinder, and a distribution mixing backflow prevention valve provided at the tip of the screw. The present invention relates to a method for molding a reinforcing fiber-containing resin molded product by using an apparatus and introducing a molding material containing a thermoplastic resin material and reinforcing fibers into the heating cylinder.

  For example, Patent Documents 1 and 2 are known as conventional techniques related to injection molding for molding a resin molded product. Patent Document 1 discloses a uniaxial plasticizing screw for injection molding in which a mixing portion and a backflow prevention valve are provided at the tip. And patent document 1 describes that resin exceeding the eccentric flight A, B, C provided in the measurement part of a screw receives a local shear, and the fusion | melting of unmelted resin is accelerated | stimulated (paragraph [ 0019]).

On the other hand, Patent Document 2 discloses an invention relating to a method for injecting a reinforcing fiber-containing thermoplastic resin composition into a mold using a screw type injection machine and an injection apparatus for carrying out the method. Patent Document 2 describes that a full flight screw is adopted as a screw in the screw type injector, and a mixing head having a check ring mechanism is attached to the tip (paragraph [0022]). ).

JP 7-256717 A JP-A-9-150436

  Among the above-mentioned conventional techniques, those described in Patent Document 1 do not describe using reinforcing fibers as a resin material and distributing and mixing the resin and fibers. Therefore, Patent Literature 1 does not disclose what molding conditions are optimal when molding a reinforced fiber-containing resin molded product.

  Moreover, in the thing of patent document 2, the molten resin extruded from the melt extruder is thrown into the screw type | mold injection machine with the reinforced fiber cut | judged with the roving cutter, and it transfers to the front-end | tip with a screw. At this time, there is a possibility that mixing of the molten resin and the reinforcing fiber by the screw is insufficient, and the resin material is not sent to the mixing head in a molten state capable of properly distributing the reinforcing fiber, and as a result, the fiber may not be sufficiently opened. In addition, there is a problem that the reinforcing fiber having a larger flow resistance may be caught by the check ring mechanism of the mixing head and clogged.

  The present invention has been made in view of the above-described problems, and provides a method capable of appropriately distributing and mixing reinforcing fibers in a resin material and molding a reinforcing fiber-containing resin molded product having good quality such as strength. The purpose is to do.

In order to achieve the above object, the invention related to the method for molding a reinforcing fiber-containing resin molded article according to claim 1 is provided with a heating cylinder, a screw fitted in the heating cylinder, and a tip side of the screw . The molten resin material and the reinforcing fiber are mixed to uniformly distribute the reinforcing fiber to the resin material, and when the molding material is stored in front of the heating cylinder, the molding material flows to the front of the heating cylinder, and An injection device including a distribution mixing backflow prevention valve that prevents the molding material from flowing backward to the rear of the heating cylinder at the time of injection is used, and the molding material containing the thermoplastic resin material and the reinforcing fiber is put into the heating cylinder. a method of molding a reinforced fiber containing resin molded article, the between the flight portion of the screw the distributive mixing check valve, is configured to have a larger diameter than the diameter of the shaft portion of the flight portion of the screw the Resin material May be provided a melt acceleration portion to promote fusion, by rotating the screw about an axis, and kneaded with heating the molding material, suitably distribute the reinforcing fibers in the distributive mixing check valve in the resin material said molding material thermally sufficiently heated to melting conduction to the resin material from the heating cylinder close to the inner hole of the heating tube mixed to the extent sufficient to by the melt acceleration portion, the The molding material in a state where the resin material is sufficiently melted is sent to the distribution mixing backflow prevention valve, and in the distribution mixing backflow prevention valve, the distribution of the reinforcing fibers of the molding material is promoted, and the front of the heating cylinder is performed. The molding material promoted to be distributed is stored, the screw is advanced in the axial direction, and the molding material stored in front of the heating cylinder is injected into a molding die.
In the invention of claim 1, a melting accelerating portion is provided between the flight portion of the screw and the distribution mixing backflow prevention valve . Cull melt promoting portion or is configured to have a larger diameter than the diameter of the shaft portion of the flight portion of the screw. The molding material heated and kneaded in the flight part of the screw is brought close to the inner hole of the heating cylinder in the melting acceleration part, and the heat from the heating cylinder is conducted. to a degree sufficient to distributive mixing, it is sufficiently heated to melting. In this state, the molding material is sent to the distribution and mixing check valve. Therefore, in the distribution / mixing backflow prevention valve, the distribution of the reinforcing fibers is promoted with respect to the sufficiently melted resin material, and as a result, the reinforcing fibers are uniformly distributed and mixed. In addition, since the resin material of the molding material is sufficiently melted and has fluidity, the reinforcing fiber is not caught by the distribution mixing backflow prevention valve and clogged. After that, when the molding material in which the reinforcing fibers are properly distributed and mixed is stored in front of the heating cylinder, the screw is advanced in the axial direction and injected into the molding die. Is formed.

In order to achieve the above object, the invention related to the method for molding a reinforcing fiber-containing resin molded article according to claim 2 is provided on a heating cylinder, a screw fitted in the heating cylinder, and a tip side of the screw. The molten resin material and the reinforcing fiber are mixed to uniformly distribute the reinforcing fiber to the resin material, and when the molding material is stored in front of the heating cylinder, the molding material flows to the front of the heating cylinder, and An injection device including a distribution mixing backflow prevention valve that prevents the molding material from flowing backward to the rear of the heating cylinder at the time of injection is used, and the molding material containing the thermoplastic resin material and the reinforcing fiber is put into the heating cylinder. In the method of molding a reinforced fiber-containing resin molded product , a plurality of protrusions are provided between the screw flight portion and the distribution mixing backflow prevention valve, and the reinforcing fibers of the molding material are distributed and mixed into the resin material. By said tree A melting promoting part is provided to promote melting of the material, the screw is rotated around the axis, the molding material is heated and kneaded, and the reinforcing fiber is appropriately applied to the resin material by the distribution mixing backflow prevention valve. The molding material is brought close to the inner hole of the heating cylinder by the melting promoting part to a sufficient extent to be distributed and mixed into the heating cylinder to conduct heat from the heating cylinder and sufficiently heat and melt the resin material, The molding material in a state where the resin material is sufficiently melted is sent to the distribution mixing backflow prevention valve, and in the distribution mixing backflow prevention valve, the distribution of the reinforcing fibers of the molding material is promoted, and the front of the heating cylinder is performed. storing the molding material is facilitated distribution, by advancing the screw in the axial direction, characterized in that injection of the molding material accumulated in front of the heating cylinder into a mold.
In the invention of claim 2, a melting accelerating portion is provided between the flight portion of the screw and the distribution mixing backflow prevention valve . Cull melt promoting portion or has a plurality of projections, it is intended to promote the melting of the resin material by distributive mixing the reinforcing fibers of the molding material to the resin material. The molding material heated and kneaded in the flight part of the screw is the melting accelerating part, and the reinforcing fibers are distributed and mixed with the resin material by a plurality of protrusions. It melts sufficiently to a sufficient extent. In this state, the molding material is sent to the distribution and mixing check valve. Therefore, in the distribution / mixing backflow prevention valve, the distribution of the reinforcing fibers is promoted with respect to the sufficiently melted resin material, and as a result, the reinforcing fibers are uniformly distributed and mixed. In addition, since the resin material of the molding material is sufficiently melted and has fluidity, the reinforcing fiber is not caught by the distribution mixing backflow prevention valve and clogged. After that, when the molding material in which the reinforcing fibers are properly distributed and mixed is stored in front of the heating cylinder, the screw is advanced in the axial direction and injected into the molding die. Is formed.

The invention according to method of molding a reinforced fiber-containing resin molded article according to claim 3, in order to achieve the above object, the invention described in any one of claims 1 or 2, wherein the melt accelerator portion among the front Stories heating cylinder and the temperature of the front side from the corresponding position, and wherein the set Teisu Rukoto to 20 to 140 ° C. range higher than the melting point of the resin material.
In the invention of claim 3, in the invention of any one of claims 1 or 2, the temperature of the front side from a position corresponding to the melting promoting portion among the heating cylinder, the melting point of the resin material 20 to 140 By setting the temperature higher, the resin material of the molding material can be reliably melted .

The invention according to the molding method of reinforcing fiber-containing resin molded article according to claim 4, in order to achieve the above object, the invention according to any one of claims 1 to 3, a pre-Symbol screw, 40～120Min ^- The back pressure is set to 0 to 5 MPa by rotating around the axis at a rotation speed of ¹ .
In invention of Claim 4, in invention of any one of Claims 1-3, a screw is rotated around an axis | shaft with the rotation speed of 40-120min < ^-1 >, The back pressure shall be 0-5 MPa. The mixing material backflow prevention valve in a state where the resin material of the molding material is surely sufficiently melted by heating and kneading the molding material in the flight part and then promoting the melting of the resin material in the melting acceleration part. Can be sent to .

In order to achieve the above object, the invention according to the method for molding a reinforcing fiber-containing resin molded article according to claim 5 is the invention according to any one of claims 1 to 4, wherein the reinforcing fiber has a fiber length of 2. A glass fiber having a diameter of ˜30 mm and a diameter of 8 to 17 μm, or a carbon fiber having a fiber length of 2 to 30 mm and a diameter of 7 to 10 μm is used.
In invention of Claim 5, in the invention of any one of Claims 1-4, fiber length is 2-30 mm, the diameter is 8-17 micrometers glass fiber, or fiber length is 2-30 mm, and a diameter is. Even if it is a molding material that is relatively difficult to distribute, such as 7 to 10 μm carbon fiber, it is realized to appropriately distribute and mix and mold a reinforced fiber-containing resin molded product having good quality such as strength.

In order to achieve the above object, the invention related to the method for molding a reinforcing fiber-containing resin molded article according to claim 6 uses a styrene resin as the resin material in the invention according to any one of claims 1 to 4. The glass fiber is used for the reinforcing fiber.
In invention of Claim 6, in the invention of any one of Claims 1-4, glass fiber is suitable for styrene resin by using a styrene resin for a resin material and using a glass fiber for a reinforcing fiber. It is realized to form a reinforced fiber-containing resin molded product having good quality such as strength by distributing and mixing.

In order to achieve the above object, the invention according to the method for molding a reinforcing fiber-containing resin molded article according to claim 7 is characterized in that in the invention according to any one of claims 1 to 6, the resin material and the reinforcing fiber are used. The ratio of the reinforcing fibers to the total material combined is 10 to 60% by weight.
In invention of Claim 7, in the invention of any one of Claims 1-6, the ratio of the said reinforcement fiber with respect to the whole material which match | combined the said resin material and the said reinforcement fiber is 10 to 60 weight%. Even so, it is realized that the reinforcing fiber is appropriately distributed and mixed with the resin material, and a reinforcing fiber-containing resin molded article having good quality such as strength is formed.

  According to the present invention, a reinforcing fiber-containing resin molded article having good quality such as strength can be formed by appropriately distributing and mixing reinforcing fibers with a resin material.

It is sectional drawing which showed one Embodiment of the shaping | molding apparatus used for this invention. It is sectional drawing which showed another embodiment of the shaping | molding apparatus used for this invention.

  First, an embodiment of a molding apparatus used in the present invention will be described with reference to FIG. The molding apparatus in the present embodiment includes a molding material supply device 1, an injection device 2, a molding die 3, and a mold clamping device 4.

The molding material supply device 1 includes a feed device 10 that individually supplies a resin material and a reinforcing fiber, and a weight measuring unit 11 that measures the weight of the resin material and the reinforcing fiber supplied by each feed device 10. . Each feed device 10 includes a cylinder 12 having a hopper 12a, a feed screw 13 fitted in the cylinder 12, and a servo motor 14 that rotationally drives the feed screw 13 around an axis in a controllable manner. The weight measuring means 11 can be configured by providing a load cell below the cylinder 12, for example. Each feed unit 10 controls the number of revolutions per unit time of the servo motor 14 for driving the feed screw 13 while measuring the respective weight of reinforcing fibers and Riki fat material by the weight measuring unit 11, and a resin material The supply amount of the reinforcing fiber can be controlled, and the supply amount of the resin material and the reinforcing fiber can also be controlled by simply setting the rotation speed per unit time of the feed screw 13. Further, the molding material supply device 1 may supply pellets made of resin material containing reinforcing fibers, or the continuous holes in the form of threads are dropped directly into the drop hole 20a of the heating cylinder 20 of the injection device 2. Alternatively, the continuous reinforcing fiber in the form of a thread may be cut into a predetermined length on the drop hole 20a of the heating cylinder 20 of the injection apparatus 2 and supplied into the drop hole 20a.

  The injection device 2 includes a heating cylinder 20, a screw 21 that is inserted in the heating cylinder 20 so as to be rotatable about an axis and movable in the axial direction, and a cylinder head that has a nozzle 22 a that touches the mold 3. 22 and heating means 23 for heating the heating cylinder 20 in a controllable manner. A drop hole 20a for feeding a molding material is formed above the base end side of the heating cylinder 20 (also referred to as the upstream side, which is the right side in the figure), and is supplied from each feed device 10 to the drop hole 20a. A chute 24 is provided to guide the molding material to be dropped to the drop hole 20a. A plurality of heating means 23 are provided on the cylinder head 22 including the heating cylinder 20 and the nozzle 22a, and each is heated so as to be controlled at a predetermined temperature. Generally, a band heater that generates heat when energized is employed. The heating cylinder 20 and the cylinder head 22 are set with appropriate temperatures separating the ranges. The band heater 23 is provided according to a range in which appropriate temperatures of the heating cylinder 21 and the cylinder head 22 are set. Further, a cooling means (not shown) is provided around the dropping hole 20a of the heating cylinder 20 to prevent the molding material from being inadvertently heated when being put into the heating cylinder 20.

  The screw 21 includes a flight part 25, a melting promotion part 26, a distribution / mixing backflow prevention valve 27, and a screw head 28 from the base end side toward the front front end side (left side in the figure). The flight portion 25 of the screw 21 is formed with a feed zone A, a compression zone B, and a metering zone C from the proximal end side toward the distal end side. The shaft 21a of the screw 21 has a relatively small diameter in the feed zone A, a relatively large diameter in the metering zone C, and a relatively small diameter in which the compression zone B continues from the feed zone A to the metering zone C. Are set to gradually change to a relatively large diameter.

  The screw 21 in the present embodiment is a ratio L of a length L from the proximal end of the flight portion 25 to the distal end side of the fusion promoting portion 26 with respect to the diameter D (up to a spacer described later of the distribution / mixing backflow prevention valve 27). / D is set to 18. However, the L / D of the screw 21 is not limited to this, and can be set to about 18 to 28. The diameter D of the screw 21 is not particularly limited, but a screw having a diameter of about 30 to 200 mm is often used.

Further, the compression ratio of the screw 21, that is, the volume ratio of the feed zone A and the metering zone C of the groove formed by the flight portion 25 and the shaft portion 21a of the screw 21 is more preferably 1.5 to 2.5. Can be set to 1.7 to 1.8. The surface of the screw 21 and the surface of the inner hole 20b of the heating cylinder 20 are preferably preliminarily subjected to wear resistance processing when glass fiber is used as the reinforcing fiber.

  The distribution mixing backflow prevention valve 27 includes a spacer 50 provided in front of the melting promoting portion 26 of the screw 21 and a cylindrical ring 51 provided between the spacer 50 and the screw head 28 so as to be movable in the axial direction. And.

The spacer 50 is formed with a smaller diameter than the inner hole 20 b of the heating cylinder 20. Therefore, a gap capable of feeding the molding material is formed between the outer peripheral surface of the spacer 50 and the inner hole 20 b of the heating cylinder 20. Further, the rear end surface 51 a of the ring 51 can close the gap between the outer peripheral surface of the spacer 50 and the inner hole 20 b of the heating cylinder 20 when it moves backward in the axial direction and contacts the spacer 50. It is designed as follows. Further, a stopper 28a is formed at the rear end of the screw head 28 to abut against the ring 51 when it moves forward and restrict the forward movement of the ring 51. A plurality of recesses 53 are disposed in the shaft portion 52 between the spacer 50 and the screw head 28. A plurality of holes 54 are formed in the ring 51. Further, the shaft portion 52 is designed such that the outer diameter thereof is smaller than the inner diameter of the ring 51. Hole 54 of the recess 53 and the ring 51 of the shaft portion 52 in a state where-ring 51 abuts against the stopper 28a of the screw head 28 moves forward, ring between the recess 53 and 53 adjacent to each other in the axial direction 51 Are arranged in such a relationship that the concave portion 53 is located between the holes 54 and 54 adjacent to each other in the axial direction.

  When the molding material is fed forward from the fusion promoting portion 26 through the gap between the outer peripheral surface of the spacer 50 and the inner hole 20b of the heating cylinder 20 by the rotation around the axis of the screw 21, the ring is caused by the pressure of the molding material. 51 moves axially forward. And it sends out so that the recessed part 53 formed in the axial part 52, the space 55 between the ring 51 and the axial part 52, and the hole 54 of the ring 51 may meander alternately, and, thereby, the resin material of a molding material The reinforcing fiber is distributed and mixed. Further, when the molding material is injected by advancing from the state in which the screw 21 is retracted, the ring 51 moves relative to the shaft portion 52 rearward in the axial direction by the pressure of the molding material and comes into contact with the spacer 50, The rear end surface 51a of the 51 closes the gap between the outer peripheral surface of the spacer 50 and the inner hole 20b of the heating cylinder 20, thereby preventing the back flow of the molding material.

  The melting promoting portion 26 is disposed on the upstream side of the distribution / mixing backflow prevention valve 27, that is, on the base end side of the screw 21, and promotes melting of the resin material. In the embodiment shown in FIG. A cylindrical outer peripheral surface that is disposed between the distal end side end of the flight portion 25 of the screw 21 and the distribution mixing backflow prevention valve 27 and is designed to have a larger diameter than the shaft portion 21a in the metering zone C. It is comprised by. By designing the outer peripheral surface of the melting promoting portion 26 to have a large diameter in this way, the interval between the heating cylinder 20 and the inner hole 20b is narrowed, and as a result, the heat of the heating cylinder 20 heated by the band heater 23 is used as a molding material. (This heating is referred to as external heating and is distinguished from shear heating by rotation around the axis of the screw 21), thereby promoting the melting of the resin material without breaking the reinforced resin.

  The melting promoting portion 26 is not limited to the embodiment shown in FIG. 1, and as shown in FIG. 2, a dull image portion formed by forming a plurality of protrusions 26a on the shaft portion 21a of the screw 21. Can also be configured. Further, the melting accelerating portion 26 is not limited to the embodiment shown in FIG. 1 and FIG. 2 as long as it can promote melting of the resin material. It can also be comprised by a recessed part, a some protrusion, or a groove | channel. When the melting promoting portion 26 is constituted by a plurality of recesses, a plurality of protrusions or grooves, the plurality of recesses, protrusions or grooves can be arranged so as to extend in the axial direction, and in the axial direction. Alternatively, they can be arranged in a spiral at a predetermined angle. Further, the melting promoting part 26 is configured by extending the flight part 25 of the screw 21 forward from the metering zone C, or is made intermittent by cutting out the extended flight part at a predetermined interval. Alternatively, a subflight lower (smaller in diameter) than the flight part 25 such as the metal ring zone C of the screw 21 is provided as in the so-called subflight, or the axis of the flight part 25 such as the metal ring zone C of the screw 21 is provided. It can also be configured by forming the flight part for melting promotion with a short (narrow) pitch in the direction or by forming a plurality of so-called eccentric flight parts. In these cases, the height from the shaft portion 21a of the screw 21 to the inner hole 20b of the heating cylinder 20 in the melting promoting portion 26 is the height from the shaft portion 21a to the inner hole 20b of the heating cylinder 20 in the metering zone C. It is desirable that the diameter of the shaft portion 21a of the screw 21 in the melting promotion portion 26 is set to be 1.0 to 0.4 times larger than the diameter of the shaft portion 21a in the metering zone C. In the case of adopting the melting promoting part exemplified in addition to that shown in FIG. 1, not only the melting of the resin material is promoted but also the function of distributing and mixing the reinforcing fibers into the resin material material is provided.

A screw head 28 is disposed at a further front end of the distribution / mixing backflow prevention valve 27. In the stopper 28a of the screw head 28, a plurality of grooves 29 that can feed the molding material to the front of the heating cylinder 20 are formed in the circumferential direction. The front of the screw head 28 from the stopper 28a can be designed in a substantially conical shape, and the mixing and mixing backflow prevention valve 27 and the front of the heating cylinder 20 are communicated to distribute and mix the molding material that has been distributed and mixed. A plurality of grooves (not shown) that can be sent from the backflow prevention valve 27 to the front of the heating cylinder 20 can be formed in the cylindrical portion .

  The molding die 3 is composed of a fixed die 30 and a movable die 31, and a cavity 32 having a shape corresponding to the shape of the molded product is formed by closing both the dies 30 and 31. The mold clamping device 4 includes a stationary platen 40 to which the stationary die 30 is attached, a movable platen 41 to which the movable die 31 is attached, and the stationary platen 40 is supported at the end and the movable platen 41 is inserted into an intermediate portion to move the movable platen 41. The tie bar 42 that supports the fixed platen 40 so as to be movable toward and away from the fixed platen 40 and the movable platen 41 are opened and closed by moving toward and away from the fixed platen 40, and the movable die 31 is moved relative to the fixed die 30. And a mold opening / closing means (not shown) for clamping the mold with a predetermined force when the mold is closed.

  Next, an embodiment of the method for molding a reinforced fiber-containing resin molded product of the present invention will be described in detail by using a molding apparatus configured as described above. In this embodiment, polypropylene pellets are employed as the thermoplastic resin, and glass fibers are employed as the reinforcing fibers. The glass fiber has a fiber length of 2 to 30 mm (more preferably, a fiber length of 3 to 15 mm), a diameter of 6 to 17 μm, and a glass fiber that is further bound with a binding material. Further, the molding material contains additives such as a modifier in addition to polypropylene and glass fiber, and contains 10 to 60% by weight, preferably 20 to 40% by weight of glass fiber with respect to the whole molding material. To do.

  Prior to molding the reinforced fiber-containing resin molded product, in this embodiment, between the front tip in the metering zone C of the flight part 25 of the screw 21 and the backflow prevention valve part 51 of the distribution mixing backflow prevention valve 27. In addition, a melting promoting portion 26 is provided.

  When molding a reinforced fiber-containing resin molded product, the glass fibers bound with the polypropylene pellets are individually fed into the hopper 12a of each feed device 10. The weight of the polypropylene, glass fiber, and additive contained in the molding material is accurately measured by the load cell 11 provided in the cylinder 12 of each feed device 10, and the servo motor 14 is controlled based on the measurement result. An accurate amount of the molding material can be put into the heating cylinder 20 of the injection apparatus 2 at the set ratio.

The rotation speed (rotational speed) around the axis of the screw 21 in the heating cylinder 20 of the injection apparatus 2 is 40 to 120 rotations / minute (min ⁻¹ ), more preferably 50 to 100 rotations / minute (min. ^-1 ) and the peripheral speed of the screw 21 is about 5000 to 15000 mm / min. The rotational speed of the screw 21 can be appropriately controlled according to the type of molding material, the diameter of the screw 21, and the like.

  The molding material supplied into the heating cylinder 20 is sequentially fed from the feed zone A to the compression zone B and the metering zone C along the flight part 25 of the screw 21 that is rotationally driven around the axis. At this time, each position of the cylinder head 22 including the heating cylinder 20 and the nozzle is heated to a temperature suitable for each position by the band heater 23. As the space of the feed zone A, compression zone B, and metering zone C of the screw 21 formed between the heating cylinder 20 gradually narrows, the polypropylene of the molding material generates shear heat due to the rotation of the screw 21, and The external heating is performed by the heat conducted from the heating cylinder 20 heated by the band heater 23. Therefore, the polypropylene is almost melt plasticized from the feed zone A upstream of the heating cylinder 20 to the downstream metal ring zone C through the compression zone B, and the glass fibers are dispersed and mixed. Will be.

  Here, the glass fiber contained in the molding material is broken when subjected to excessive stress in the heating cylinder 20 due to the rotation of the screw 21 or the like, and a molded product containing the set length of glass fiber is molded. Can not be. In this case, a reinforced fiber-containing resin molded product having good quality such as strength cannot be molded. On the other hand, if the polypropylene contained in the molding material is not sufficiently melt plasticized, the glass fibers cannot be mixed uniformly. If the glass fibers cannot be mixed uniformly, a reinforced fiber-containing resin molded product with good quality such as strength cannot be formed.

Therefore, in the present embodiment, the molding material is sent from the flight part 25 of the screw 21 to the melting promoting part 26. Further, in the present embodiment, of the band heaters 23 provided in the heating cylinder 20 and the cylinder head 22, the heating cylinder 20 heated by the band heater 23a located second from the front tip side excluding the nozzle 22a. Set the range to the maximum temperature. The temperature of the heating cylinder 20 in the range heated by the second band heater 23a from the front tip side can be set to about 280 ° C., for example. Furthermore, in this embodiment, 40～120Min as described above the rotation speed of the screw 21 ^-1, more preferably set to 50～100Min ^-1, also as described below the back pressure of the screw 21 0 Set to ~ 5 MPa. The melting point of polypropylene is that of a homopolymer used in general injection molding, and is 160 to 165 ° C. Depending on the melting point depending on the type of polypropylene, the thermoplastic resin may be other than polypropylene. In the case of adopting the above, the heating temperature of the heating cylinder 20 can be set according to the melting point depending on the type of the thermoplastic resin. Here, in the above description, the relationship between the melting point of the thermoplastic resin material and the setting of the heating temperature of the heating cylinder 20 is as follows. That is, the range set to the maximum temperature of the heating cylinder 20 including the cylinder head 22 (usually the cylinder head 22 positioned at the front end of the heating cylinder 20 or the vicinity of the front where the cylinder head 22 of the heating cylinder 20 is attached) The temperature of the range is set higher by 20 to 140 ° C. (more preferably 20 to 70 ° C.) than the temperature of the melting point.

  A molding material containing polypropylene plasticized and melted by rotation about the axis of the screw 21 and dispersed glass fibers mixed therewith is sent out from the flight part 25 to the melting promoting part 26. In the melting promoting portion 26 in the embodiment shown in FIG. 1, the width (height) of the flow path is narrower than the metalling zone C of the flight portion 25 (the diameter of the shaft portion 21a of the screw 21 in the melting promoting portion 26 is smaller). Therefore, the molding material is further externally heated by the band heater 23 via the heating cylinder 20. Thus, the molding material has a size larger than the diameter of the shaft 21 a of the screw 21 in the metering zone C). Therefore, the polypropylene of the molding material melt-plasticized in the flight part 25 is further promoted to melt, and as a result, there is no remaining melt of the polypropylene and the polypropylene is sufficiently melted. Here, the state in which the polypropylene as the resin material is sufficiently melted means that the flight portion 25 has a degree sufficient to appropriately distribute and mix the glass fiber as the reinforcing fiber into the polypropylene by the distribution and mixing backflow prevention valve 27. This means that the melt-plasticized polypropylene is further melted, which means that the unmelted polypropylene does not remain and is completely melted.

  In the embodiment shown in FIG. 2, the diameter of the shaft portion 21a of the screw 21 in the melting promotion portion 26 is substantially the same as the diameter of the shaft portion 21a of the screw 21 in the metering zone C. By forming a plurality of projections 26a such as a dull image portion on the shaft portion 21a of the screw 21 at 26, not only the polypropylene is externally heated by the band heater 23, but also melting is promoted, and the glass fiber relative to the polypropylene Distribution is also promoted.

The molding material in which the polypropylene is sufficiently melted in the melting accelerating portion 26 is further sent from the melting accelerating portion 26 to the distribution and mixing backflow prevention valve 27 by the rotation around the axis of the screw 21. At this time, it is moved forward relative to the shaft portion 52 by the pressure of the molding material sent from the upstream (base end side of the screw 21) toward the downstream side (front tip side of the screw 21). The rear end surface 51 a of the ring 51 of the prevention valve 27 is in a state of being separated from the spacer 50 provided on the screw 21. Therefore, the molding material flows between the outer peripheral side surface of the spacer 50 and the inner hole 20 b of the heating cylinder 20 and flows in front of the spacer 50. Then, the molding material alternately passes through the recesses 53 formed in the shaft portion 52, the space 55 between the ring 51 and the shaft portion 52, and the hole 54 of the ring 51. The molding material at this time does not flow linearly in parallel with the axial direction of the screw 21 but flows meandering. Therefore, the glass fiber is distributed and mixed in a uniform distribution by the distribution / mixing backflow prevention valve 27 to the polypropylene which has been melted externally without being subjected to shearing heat generation by the melting promoting portion 26. Thereafter, most of the distributed and mixed molding material passes through the groove 29 of the stopper 28 a and is fed forward in the heating cylinder 20.

  As the molding material is sent and stored in front of the heating cylinder 20, the screw 21 moves backward in the axial direction. The back pressure of the screw 21 at this time is set to be 0 to 5 MPa in terms of resin pressure. By setting the back pressure of the screw 21 in this manner, the glass fiber is not stressed. Therefore, the glass fiber is mixed with polypropylene while maintaining a predetermined length without breaking, and the heating cylinder 20 It will be sent forward and stored.

  When the molding material stored in front of the heating cylinder 20 reaches a set amount (measuring step) and, as a result, the screw 21 is retracted to a predetermined position, the injection device 2 prepares for the injection step in the next cycle of the molding material. Is in a standby state. In this standby state, the ring 51 is moved rearward in the axial direction relative to the shaft portion 52 by the pressure of the molding material by rotating the screw 21 in the opposite direction around the axis or moving the screw 21 in the axial direction. The rear end surface 51a of the ring 51 may be brought into contact with the spacer 50 to close the gap between the outer peripheral surface of the spacer 50 and the inner hole 20b of the heating cylinder 20.

  In addition, at the same time as the molding material measuring step of storing a predetermined amount of molding material in front of the heating cylinder 20 by the injection device 2, until the molding material is filled into the cavity 32 in the previous cycle and the molded product has a stable shape, For example, the mold is cooled until the temperature of the mold reaches about 40 ° C. (preferably in the range of 35 to 50 ° C.) (cooling step of the molded product). That is, the molding material weighing step and the molded product cooling step are performed in a partially overlapping manner. In general, the cooling process of a molded product often takes longer than the weighing process of a molding material. Therefore, the injection device 2 is in a standby state until the cooling process of the molded product is completed after the weighing process.

  When the cooling process of the molded product is completed, the movable mold 31 is released from the fixed mold 30 by the mold clamping device 4 and the mold is opened, and the molded product is taken out from the molding die 3, and then is fixed to the fixed mold 30 by the mold clamping device 4. On the other hand, the movable mold 31 is closed and clamped, and the nozzle of the heating cylinder is touched by the fixed mold to advance the screw 21 in the axial direction, and a predetermined amount of molding material stored in front of the heating cylinder 20 is stored. Into the cavity 32 by injection filling. At the time of injection filling, the ring 51 is moved axially rearward relative to the shaft portion 52 due to the pressure of the molding material, the rear end surface 51a of the ring 51 abuts against the spacer 50, and the outer peripheral surface of the spacer 50 and the heating cylinder The gap between the 20 inner holes 20b is closed to prevent the back flow of the molding material.

  The injection speed at this time can be 20 to 90 mm / sec (more desirably 30 to 70 mm / sec). Here, the injection speed in general injection molding is about 100 mm / sec. In contrast, in the present embodiment, the injection is performed at an injection speed that is slower than the injection speed in general injection molding. Thus, the glass fiber of the set length is contained by preventing the glass fiber from breaking by making the injection speed of the molding material containing glass fiber slower than the injection speed in general injection molding. The molded product can be molded,

  In addition to polypropylene, thermoplastic resins include crystalline resins such as polyethylene, polyamide, polyacetal, and polyethylene terephthalate, styrene resins such as GPPS or HIPS, AS, and ABS, and amorphous resins such as acrylic and polycarbonate. Can be used.

Moreover, the molding material in the case of shape | molding the components for household appliances especially as a molded article may combine a styrene resin as a thermoplastic resin, and a glass fiber as a reinforced fiber. In this case, the melting temperature defined as the melting point of the styrene resin is 100 ° C. Assuming that this melting temperature is substantially the same as the glass transition temperature Tg, the maximum temperature of the heating cylinder 20 and cylinder head 22 (excluding the nozzle 22a) is 180 to 240 ° C, which is obtained by adding 80 to 140 ° C to this melting temperature. Can be set to Then, the maximum heating temperature shall be the most forward or set temperature of the band heater 23 a provided in the second position from the top front of the cylinder head 22 excluding the heating cylinder 20 and the nozzle 22a among the band heater 23 Can do.

  Furthermore, the reinforcing fibers are not limited to glass fibers, and other fibers such as carbon fibers and a mixture of glass fibers and carbon fibers can also be adopted. When carbon fiber is employed, the content is 10 to 60% by weight (preferably 20 to 40% by weight) of the entire molding material, and the fiber length is 2 to 30 mm (more preferably the fiber length is 3 to 15 mm). The fiber diameter is preferably 5 to 15 μm (preferably 7 to 8 μm). In the present invention, even if the diameter of the carbon fiber is as thin as 7 to 8 μm, it can be distributed and mixed well. In the present invention, even if the diameter of the carbon fiber is as thin as 7 to 8 mm, it can be distributed and mixed well. Further, the reinforcing fiber may be a recycled fiber.

  Furthermore, although the thermoplastic resin material and the reinforcing fiber occupy the main proportion of the molding material, both the resin material and the reinforcing fiber may not be one type. Furthermore, the additive may contain a colorant, a lubricant, a flame retardant, a stabilizer and the like as necessary in addition to the modifier.

Here, the above-described configuration is summarized as follows.
1. In the state where the resin material of the molding material sent from the flight unit 25 is sufficiently melted by the melting acceleration unit 26 provided in advance on the upstream side of the distribution mixing backflow prevention valve 27 of the screw 21, this molding material is distributed and mixed. The mixture is fed to the backflow prevention valve 27, and the sufficiently melted resin material and reinforcing fiber are distributed and mixed by the distribution mixing backflow prevention valve 27.
2. The front tip side of the heating cylinder 20 is heated by 20 to 140 ° C. higher than the melting point of the resin material from the position corresponding to the melting promoting portion 26 on the upstream side of the distribution mixing backflow prevention valve 27 of the screw 21.
3. The rotational speed of the screw 40~120min ^-1, more preferably set to 50~100min ^-1, set the back pressure of the screw on the 0 to 5 MPa.

  Each of the above configurations 1 to 3, together with the molding material in a sufficiently molten state, prevents the breakage of the reinforcing resin as much as possible and sends it to the distribution / mixing backflow prevention valve to distribute and mix the reinforcing fibers into the resin material. it can. Therefore, the above configurations 1 to 3 can be performed alone or in combination as appropriate.

  1: Molding material supply device, 2: Injection device, 3: Mold, 4: Clamping device, 20: Heating cylinder, 21: Screw, 23: Band heater (heating means), 25: Flight part, 26: Melting promotion 27: Distributive mixing backflow prevention valve 50: Spacer 51: Backflow prevention valve

Claims (7)

A heating cylinder, a screw fitted in the heating cylinder, provided on the tip side of the screw, mixing the molten resin material and the reinforcing fiber, and uniformly distributing the reinforcing fiber to the resin material; An injection device comprising a distribution mixing backflow prevention valve that prevents the molding material from flowing in front of the heating cylinder when storing the molding material in front of the heating cylinder, and prevents the molding material from flowing backward to the rear of the heating cylinder during injection. a method of using a molding material containing and the reinforcing fibers of the thermoplastic resin material is charged into the heating cylinder, forming the reinforcing fiber-containing resin molded article,
Provided between the flight part of the screw and the distribution mixing backflow prevention valve is a melting promoting part configured to be larger than the diameter of the shaft part in the flight part of the screw to promote the melting of the resin material. Every
Rotating the screw around an axis to heat and knead the molding material, and the melting promoting portion to an extent sufficient to appropriately distribute and mix the reinforcing fiber to the resin material with the distribution and mixing backflow prevention valve said molding material thermally sufficiently heated to melting conduction to the resin material from the heating cylinder close to the inner hole of the heating cylinder by the molding of a state where the resin material is sufficiently melted Sending the material to the distribution mixing backflow prevention valve, promoting the distribution of the reinforcing fibers of the molding material in the distribution mixing backflow prevention valve, and storing the molding material whose distribution is promoted in front of the heating cylinder;
A method for molding a reinforced fiber-containing resin molded product, wherein the screw is advanced in the axial direction and the molding material stored in front of the heating cylinder is injected into a molding die. A heating cylinder, a screw fitted in the heating cylinder, provided on the tip side of the screw, mixing the molten resin material and the reinforcing fiber, and uniformly distributing the reinforcing fiber to the resin material; An injection device comprising a distribution mixing backflow prevention valve that prevents the molding material from flowing in front of the heating cylinder when storing the molding material in front of the heating cylinder, and prevents the molding material from flowing backward to the rear of the heating cylinder during injection. In the method of charging a molding material containing the thermoplastic resin material and reinforcing fibers into the heating cylinder, and molding a reinforcing fiber-containing resin molded product ,
A melting accelerating portion that has a plurality of projections between the flight portion of the screw and the distribution mixing backflow prevention valve and promotes melting of the resin material by distributing and mixing the reinforcing fibers of the molding material into the resin material. Set up
Rotating the screw around an axis to heat and knead the molding material, and the melting promoting portion to an extent sufficient to appropriately distribute and mix the reinforcing fiber to the resin material with the distribution and mixing backflow prevention valve The reinforcing fibers are distributed and mixed with the resin material in advance by the plurality of protrusions to sufficiently melt the resin material, and the molding material in a state where the resin material is sufficiently melted is sent to the distribution and mixing check valve. The distribution mixing backflow prevention valve promotes the distribution of the reinforcing fibers of the molding material, and stores the molding material whose distribution is promoted in front of the heating cylinder,
Wherein the screw is advanced in the axial direction, <br/> molding method of strengthening the fiber-containing resin molded article you characterized in that injection of the molding material accumulated in front of the heating cylinder into a mold. The temperature of the front side from a position corresponding to the said molten promoting portion among the front Symbol heating cylinder, and wherein the set Teisu Rukoto to 20 to 140 ° C. range higher than the melting point of the resin material according to claim 1 or 2 A method for molding a reinforced fiber-containing resin molded product according to any one of the above . The pre-Symbol screw, is rotated around the axis at a rotational speed of 40～120Min ^-1, reinforcing fibers according to any one of claims 1 to 3, characterized in that the back pressure and 0~5MPa Molding method of contained resin molded product.   5. A glass fiber having a fiber length of 2 to 30 mm and a diameter of 8 to 17 μm, or a carbon fiber having a fiber length of 2 to 30 mm and a diameter of 7 to 10 μm is used as the reinforcing fiber. The molding method of the reinforced fiber containing resin molding of any one of these.   The method for molding a reinforced fiber-containing resin molded article according to any one of claims 1 to 4, wherein a styrene-based resin is used as the resin material and a glass fiber is used as the reinforcing fiber.   The reinforcing fiber content according to any one of claims 1 to 6, wherein a ratio of the reinforcing fiber to the entire material including the resin material and the reinforcing fiber is 10 to 60% by weight. Molding method for resin molded products.

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