JP2013028020A - Method of molding resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of molding a resin molded product that uses crystalline polymer resin and can easily and securely achieve a method of improving crystallinity of the resin.SOLUTION: In a molding die 11, by applying torsion force to crystalline polymer resin materials A'2, A'3 whose temperature is the melting point or lower and the crystallization temperature or higher, the resin materials A'2, A'3 are extended at a strain rate equal to or exceeding a critical extension strain rate, and are molded to undergo crystallization following an oriented melting state. At this time, it is preferable to apply, together with the torsion force, at least one of tensile force or compressive force along a direction approximately parallel with a rotating axis of the torsion force.

Description

  The present invention relates to a method for molding a resin molded product such as an automotive part, particularly a molded product using a crystalline polymer resin, and belongs to the field of resin molded product molding technology.

  Conventionally, so-called general-purpose plastics such as polypropylene, polyethylene, polystyrene, or polyvinyl chloride are widely used in various fields as a material for resin molded products because they are inexpensive and have excellent moldability. However, as a material for industrial products such as automobile parts and machine parts, sufficient mechanical strength and durability may not be obtained.

  For this reason, so-called engineering plastics such as polyethylene terephthalate, polycarbonate, and polyamide are preferably used as industrial product materials that require these characteristics. However, since engineering plastics are expensive, the material cost increases. There is a drawback.

  In order to cope with such a situation, Patent Document 1 discloses that engineering plastics can be used while using a general-purpose plastic material such as polypropylene by greatly improving the crystallinity at the time of molding a crystalline polymer resin melt. An invention that realizes mechanical strength and heat resistance corresponding to the above is disclosed.

  The present invention is characterized in that a melt of a crystalline polymer resin is stretched in a predetermined direction at a strain rate equal to or higher than a critical elongation strain rate in a state below the melting point and above the crystallization temperature, in other words, in a supercooled state. To do. The melt thus stretched becomes an oriented melt in which the polymer chains are stretched and aligned in parallel, and a large number of nuclei serving as crystallization base points are formed in the melt. In addition, since crystallization occurs at a very high rate, it is expected that a molded product having excellent mechanical strength and heat resistance can be obtained.

  Here, the critical elongation strain rate is the rate at which the crystal size becomes discontinuously smaller when the supercooled melt is stretched and the strain rate in the stretching direction is increased. By extending at a rate higher than the speed, the degree of crystallinity is greatly improved as compared with the case of crystallization by a conventional method.

  In Patent Document 1, as a method for realizing an elongation strain rate equal to or higher than the critical rate, a sample of a disk-shaped polymer resin melt is sandwiched between upper and lower plates, and this is kept in a supercooled state. , A method of crushing by moving one plate toward the other plate at a constant speed, a method of discharging the polymer resin melt at a high speed while rapidly cooling from the discharge port of the die, a polymer resin by a pair of drawing rollers A method of drawing a melt from a die while rapidly cooling it is disclosed.

International Publication WO2008 / 108251

  However, in the method of sandwiching the polymer resin melt sample between the upper and lower plates described in Patent Document 1, it is necessary to prepare the sample in advance and the periphery has an irregular shape. Other processes such as molding are required.

  In addition, the method of discharging the polymer resin melt from the die can only obtain a long product having a constant cross-sectional shape, and the method of drawing the polymer resin melt with a pair of rollers is also in the form of a film. In order to obtain a product by laminating them, the resin must be melted again, and the strength improved by crystallization is reduced.

  In contrast, a normal injection molding method using a mold has a higher degree of freedom in product shape than the above methods, but only a shear strain occurs at the time of injection. Even the critical elongation strain rate cannot be obtained.

  In view of the above problems, as a method of forming a polymer resin melt so as to cause elongation strain at a speed equal to or higher than the critical elongation strain rate while using a molding die, After the polymer resin melt containing the foaming agent is injected and filled in the cavity surrounded by, the movable mold moves at a high speed in the direction away from the fixed mold when the melt is in a supercooled state ( Hereinafter, it is also possible to extend the polymer resin material at a high speed in the core back direction by forming the polymer resin material while foaming.

  However, in this case, in order to obtain a very large core back speed, there is a disadvantage that a very expensive device such as a servo valve is required. Further, if the rising speed of the core back is insufficient, or if the polymer resin material in the cavity cannot sufficiently follow the movable mold in the core back, it is impossible to reliably realize an elongation strain higher than the critical elongation strain rate.

  Also, when press molding a polymer resin material, it is possible to extend a part of the resin material in the press direction at a speed equal to or higher than the critical elongation strain rate by pressing at a high speed. It is essential to use expensive equipment to obtain very high press speeds. Further, if the press speed is insufficient, it is impossible to reliably realize an elongation strain higher than the critical elongation strain rate.

  Then, this invention makes it a subject to provide the shaping | molding method of the resin molded product which can implement | achieve the said method of improving the crystallinity easily and reliably using crystalline polymer resin.

  In order to solve the above-described problems, the method for molding a resin molded product according to the present invention is configured as follows.

  First, the invention according to claim 1 of the present application applies a torsional force to a crystalline polymer resin material having a temperature not higher than a melting point and not lower than a crystallization temperature in a mold, thereby causing the resin material to stretch critically. It is characterized in that it is stretched at a strain rate equal to or higher than the strain rate and molded so as to be crystallized through an oriented melt state.

  Next, the invention according to claim 2 is the invention according to claim 1, wherein when the resin material is stretched at a strain rate equal to or higher than a critical elongation strain rate, the rotational shaft of the torsional force is combined with the torsional force. And applying at least one of a tensile force and a compressive force along a direction substantially parallel to.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the resin material is a general-purpose plastic.

  The invention according to claim 4 is the invention according to claim 3, wherein the general-purpose plastic is polypropylene.

  According to the first aspect of the present invention, the crystalline polymer resin material in a supercooled state (below the melting point and above the crystallization temperature) is strained at a critical elongation strain rate or higher by a torsional force applied in the mold. By stretching at a speed, the entangled polymer chains are stretched to form an oriented melt that is aligned in parallel, and a large number of nuclei that form the basis of crystallization are formed in the melt. In addition, since nanocrystals are formed at a high rate, a resin molded product having a very high degree of crystallinity can be obtained.

  In the invention described in claim 1, the torsional force necessary for realizing an elongation strain equal to or higher than the critical elongation strain rate of the crystalline polymer resin material is relatively easy by using an inexpensive servo motor or the like. You can definitely get it. That is, it is easy to avoid the need for an expensive device such as a servo valve or a lack of speed as in the case where only the force in the translational direction is applied to the resin material. Molding with high crystallinity can be realized easily and reliably.

  Furthermore, according to the invention described in claim 2, when the crystalline polymer resin material is stretched at a strain rate equal to or higher than the critical elongation strain rate, in addition to the torsional force, it is substantially parallel to the rotational axis of the torsional force. Since at least one of the tensile force or the compressive force along the direction is used, the resin material can be extended not only in the extending direction by the torsional force but also in the extending direction by the tensile or compressive force. Therefore, the elongation strain rate of the resin material can be further increased, and the crystallinity of the resin material can be further improved.

  According to the invention described in claim 3, since a crystalline general-purpose plastic such as polypropylene or polyethylene is used as the resin material, a molded product can be manufactured at low cost.

  Furthermore, according to the invention described in claim 4, since polypropylene which is widely used as the general-purpose plastic is adopted, it is further advantageous in terms of price and availability.

It is a block diagram of the shaping | molding apparatus used with the shaping | molding method which concerns on 1st Embodiment. It is the sectional view on the AA line of FIG. It is a figure which shows the state which the injection process of the apparatus shown in FIG. 1 completed. It is a figure which similarly shows the state of a crystallization process. It is a block diagram of the shaping | molding apparatus used with the shaping | molding method which concerns on 2nd Embodiment. It is a figure which shows the state of the crystallization process of the apparatus shown in FIG. It is a block diagram of the shaping | molding apparatus used with the shaping | molding method which concerns on 3rd Embodiment. It is a figure which shows the state pressed with the apparatus shown in FIG. It is a block diagram of the shaping | molding apparatus used with the shaping | molding method which concerns on 4th Embodiment. It is a figure which shows the state of the crystallization process of the apparatus shown in FIG. It is a block diagram of the shaping | molding apparatus used with the shaping | molding method which concerns on 5th Embodiment. It is the BB sectional drawing of FIG. It is a figure which shows the state which the injection process of the apparatus shown in FIG. 11 was completed. It is a figure which shows the state which the 1st core back process of the apparatus shown in FIG. 11 was completed. It is a figure which shows the state of the 1st crystallization process of the apparatus shown in FIG. It is a figure which shows the state which the 2nd core back process of the apparatus shown in FIG. 11 was completed. It is a figure which shows the state of the 2nd crystallization process of the apparatus shown in FIG. It is a block diagram of the shaping | molding apparatus used with the shaping | molding method which concerns on 6th Embodiment.

  Hereinafter, embodiments of the present invention will be described.

[First Embodiment]
FIG. 1 shows a molding apparatus 10 used for molding a resin molded product by the molding method according to the first embodiment of the present invention. The molding apparatus 10 injects a resin melt into a mold 11 having a first mold 12 and a second mold 13 and a cavity 15 surrounded by the first mold 12 and the second mold 13. And an injection device 16.

  The first mold 12 of the molding die 11 is provided with an injection passage 18 that leads to the surface constituting the cavity 15, that is, the molding surface 12 a and the exposed surface 12 b to the outside. The melt injected from 16 is guided to the cavity 15.

  On the other hand, the molding surface of the second mold 13 extends from the facing surface 13a of the first mold 12 to the molding surface 12a and from the periphery of the facing surface 13a toward the periphery of the molding surface 12a of the first mold 12. And a cylindrical inner peripheral surface 13b. The cylindrical inner peripheral surface 13b is provided with a plurality of protrusions 24 extending in the axial direction of the cylindrical inner peripheral surface 13b. As shown in FIG. 2, the protrusions 24 are arranged without gaps over the entire circumference of the cylindrical inner peripheral surface 13b, and each protrusion 24 is formed in, for example, a triangular cross section. Since the protruding portion 24 is provided in this way, the cylindrical inner peripheral surface 13b is an uneven surface as a whole, and thus the cylindrical inner peripheral surface 13b is supercooled as described later. As a result, the resin material in the cavity 15 whose viscosity has increased is easily adhered.

  However, the extending direction, arrangement, and cross-sectional shape of the protruding portion 24 are not limited to the above-described configuration. For example, the protruding portion 24 is in a direction inclined with respect to the axial direction of the cylindrical inner peripheral surface 13b. It may be extended. In addition, as a configuration for making the cylindrical inner peripheral surface 13b an uneven surface, a configuration other than the configuration in which the protrusions 24 are provided may be employed. For example, a plurality of grooves are formed in the cylindrical inner peripheral surface 13b. Alternatively, the concave and convex portions may be formed on the cylindrical inner peripheral surface 13b by applying a graining process or a blasting process.

  Returning to FIG. 1, a disk-shaped rotating body 20 is interposed between the molding surface 12 a of the first mold 12 and the facing surface 13 a of the second mold 13, and thereby the cavity Reference numeral 15 denotes a ring-shaped space surrounding the rotating body 20.

  For example, the tip of a rotating shaft 28 connected to a driving source such as a motor (not shown) is connected to the central portion of the rotating body 20, and when the rotating shaft 28 is rotationally driven by the driving source, the rotation is performed. Together with the shaft 28, the rotating body 20 is driven to rotate about the rotating shaft 28. In the present embodiment, the rotary shaft 28 is provided through the first mold 13, but may be provided through the second mold 12.

  A plurality of protrusions 22 extending in the thickness direction of the rotating body 20 are provided on the outer peripheral surface of the rotating body 20. As shown in FIG. 2, the ridges 22 are arranged without gaps over the entire circumference of the outer peripheral surface of the rotating body 20, and each ridge 22 is formed in a triangular cross section, for example. Thereby, since the outer peripheral surface of the rotating body 20 is also an uneven surface similar to the cylindrical inner peripheral surface 13b, the supercooled resin material can easily adhere to the outer peripheral surface of the rotating body 20. ing.

  However, as with the cylindrical inner peripheral surface 13b, various changes can be made to the configuration of the protruding portion 22 on the outer peripheral surface of the rotating body 20, and a groove is provided instead of the protruding portion 22. Concavities and convexities may be formed on the outer peripheral surface of the rotating body 20 by forming, applying a texture process, or performing a blasting process.

  Returning to FIG. 1, the injection device 16 includes a cylinder 16 a, a hopper 16 b that supplies a resin material into the cylinder 16 a at one end portion of the cylinder 16 a, and heat-melts the supplied resin material. A screw 16d that pumps the melt toward the discharge port 16c provided at the other end of the cylinder 16a; The cylinder 16 a is attached to the first mold 12 so that the discharge port 16 c is connected to one end of the injection passage 18 provided in the first mold 12 of the molding die 11.

  The type of the resin material is not particularly limited as long as it is a crystalline polymer resin. However, in terms of price and availability, crystalline general-purpose plastics such as polypropylene and polyethylene are preferably used, and among these, polypropylene is particularly preferable. Preferably used.

  Moreover, it is preferable to add to the resin material an ultra high molecular weight component having a main chain having a length equal to or longer than the distance between the outer peripheral surface of the rotating body 20 and the cylindrical inner peripheral surface 13b. Although details will be described later, the addition of the ultra-high molecular weight component facilitates the crystallization described below starting from the component. Alternatively, in place of the addition of the ultrahigh molecular weight component, a functional group (for example, a carboxyl group and a hydroxyl group) for attracting the ends of the polymer is added, thereby making a pseudo-comprising of a plurality of polymers attracted to each other. An ultrahigh molecular weight component may be formed, and the same effect can be obtained by this.

  Next, a method for molding a resin molded product using the molding apparatus 10 will be described.

  As shown in FIG. 3, first, the mold 11 is clamped by a mold opening / closing device (not shown). In parallel with this, the solid crystalline polymer resin material A is put into the hopper 16b of the injection device 16, and the screw 16d is operated in the cylinder 16a to heat the resin material A to the melting point or higher. And melted to obtain melt A ′.

  Next, as the injection process, the melt A ′ is injected into the cavity 15 by the injection device 16 and filled.

  Subsequently, when the melt A ′ in the cavity 15 is cooled and the temperature falls below the melting point and above the crystallization temperature, that is, at the timing when the melt A ′ enters a supercooled state, as shown in FIG. In addition, as a crystallization process, the rotating body 20 is rotated at a high speed together with the rotating shaft 28 by a driving source (not shown). Thereby, a torsional force along the rotation direction of the rotating body 20 is applied to the melt A ′ in the cavity 15, and an elongation strain along the rotation direction is generated.

  The rotational speed of the rotating body 20 is set to a speed at which the elongation strain rate of the melt A ′ is equal to or higher than the critical elongation strain rate. Therefore, the rotation of the rotating body 20 causes the melt A ′ to expand at a speed equal to or higher than the critical elongation strain rate, and the entangled polymer chain is stretched to become an aligned melt aligned in parallel and crystallized. Numerous nuclei serving as the base point of are formed in the melt A ′, and thereafter, crystallization occurs in a short time and at a very high rate. Since this crystallization occurs in a very short time, the rotation driving time of the rotating body 20 may be very short.

  In addition, as described above, if an ultrahigh molecular weight component is added to the resin material A in advance or a functional group for forming a pseudo ultrahigh molecular weight component is added, the ultrahigh molecular weight component or One end of the main chain of the pseudo ultra-high molecular weight component is constrained to the outer peripheral surface of the rotating body 20, and the other end is constrained to the cylindrical inner peripheral surface 13b, so that the component follows the rotation of the rotating body 20. Therefore, the elongation strain of the entire melt A ′ is promoted starting from the component.

  After the crystallization step, when the mold 11 is cooled to a predetermined temperature, the mold is opened, whereby a highly crystallized resin molded article excellent in mechanical strength and heat resistance can be obtained.

  According to this embodiment, in order to realize an elongation strain equal to or higher than the critical elongation strain rate of the crystalline polymer resin material, the torsional force generated by the high-speed rotation of the rotating body 20 is used, and the required torsional force is applied. The necessary rotational speed of the rotating body 20 can be obtained relatively easily and reliably by using an inexpensive servo motor or the like. Therefore, according to the present embodiment, it is possible to easily and reliably realize molding with an elongation strain equal to or higher than the critical elongation strain rate of the resin material, and thus with a high crystallinity.

  Further, since the injection process and the crystallization process are continuously performed using a single molding apparatus 10, a resin molded product having a high crystallinity can be efficiently produced.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS. Note that in the second embodiment, detailed description of the same configuration as in the first embodiment is omitted. In FIGS. 5 and 6, members having the same functions as those in the first embodiment are denoted by the same reference numerals.

  FIG. 5 shows a molding apparatus 30 used for molding a resin molded product by the molding method according to the second embodiment. The molding apparatus 30 injects a resin melt into a mold 11 having a first mold 12 and a second mold 13 and a cavity 15 surrounded by the first mold 12 and the second mold 13. And an injection device 16.

  The molding surface 12a of the first mold 12 is provided with, for example, a circular accommodation recess 32, and the accommodation recess 32 is, for example, a disc-shaped slide member 34 so as to close the open end of the accommodation recess 32. Is housed. One end of a support shaft 36 that passes through the bottom surface of the housing recess 32 is connected to the slide member 34. The other end of the support shaft 36 is connected to a drive source (not shown) for sliding the slide member 34 along with the support shaft 36 in the axial direction.

  On the other hand, the second mold 13 is provided with, for example, a circular through hole 40 at a position facing the accommodation recess 32, and a rotation projecting pin 42 is fitted into the through hole 40. The base end portion of the rotation projecting pin 42 is connected to a drive source (not shown) for rotating the rotation projecting pin 42 in the axial direction while rotating the shaft about the axial direction. Can be projected and retracted from the facing surface 13a to the first mold 12 side by sliding in the axial direction.

  The configuration of the injection device 16 and the resin material used are the same as those in the first embodiment.

  Moreover, it is preferable to add to the resin material an ultrahigh molecular weight component having a main chain having a length approximately equal to or longer than the radius of the housing recess 32, whereby crystallization described later easily occurs. Become. Alternatively, in place of the addition of the ultrahigh molecular weight component, a functional group (for example, a carboxyl group and a hydroxyl group) for attracting the ends of the polymer is added, thereby making a pseudo-comprising of a plurality of polymers attracted to each other. An ultrahigh molecular weight component may be formed, and the same effect can be obtained by this.

  Next, a method for molding a resin molded product using the molding apparatus 30 will be described.

  As shown in FIG. 5, first, the mold 11 is clamped by a mold opening / closing device (not shown). At this time, the surface of the slide member 34 on the cavity 15 side is flush with the molding surface 12a of the first die 12, and the tip surface of the rotary protruding pin 42 is flush with the facing surface 13a.

  In parallel with this, the solid crystalline polymer resin material A is put into the hopper 16b of the injection device 16, and the screw 16d is operated in the cylinder 16a to heat the resin material A to the melting point or higher. And melted to obtain melt A ′.

  Next, as the injection process, the melt A ′ is injected into the cavity 15 by the injection device 16 and filled.

  Subsequently, when the melt A ′ in the cavity 15 is cooled and the temperature falls below the melting point and above the crystallization temperature, that is, at the timing when the melt A ′ enters a supercooled state, as shown in FIG. In addition, as a crystallization process, while the slide member 34 is slid by the drive source (not shown) toward the bottom surface of the housing recess 32 until it comes into contact with the bottom surface, the rotary protrusion pin 42 is moved at high speed by another drive source (not shown). Slidably moved so as to protrude from the facing surface 13a toward the first mold 12 side. At this time, each slide movement of the slide member 34 and the rotation projecting pin 42 is performed at such a speed and timing that the distance between the members 34 and 42 in the slide direction is gradually reduced from the start of the slide movement to the end of the slide movement.

  In this crystallization step, the melt portion A′2 near the side surface of the rotary protruding pin 42 has a twisting force along the rotational direction of the rotary protruding pin 42 and a direction substantially parallel to the axial direction of the rotary protruding pin 42. A tensile force along the direction is applied, and an elongation strain in both directions occurs.

  On the other hand, the melt portion A′3 between the tip surface of the rotating protrusion pin 42 and the slide member 34 is substantially parallel to the axial direction of the rotating protrusion pin 42 together with the torsional force along the rotation direction of the rotating protrusion pin 42. A compressive force is applied along the various directions, and an elongation strain occurs in the rotational direction and shear direction of the rotary protruding pin 42.

  The rotation speed of the rotation protrusion pin 42 and the slide movement speed of the rotation protrusion pin 42 and the slide member 34 are set to a speed at which the elongation strain rate of the melt A ′ is equal to or higher than the critical elongation strain rate. However, the force causing the elongation strain of the melt portions A′2 and A′3 is mainly the torsional force, and the tensile force or the compressive force plays an auxiliary role. It is important to speed up.

  Through this crystallization step, the melt portions A′2 and A′3 are stretched at a speed equal to or higher than the critical elongation strain rate, and the entangled polymer chains are stretched to become an aligned melt aligned in parallel. A large number of nuclei as crystallization base points are formed in the melt portions A′2 and A′3, and thereafter, crystallization occurs in a short time and at a very high rate.

  In addition, as described above, if an ultrahigh molecular weight component is added to the resin material A in advance or a functional group for forming a pseudo ultrahigh molecular weight component is added, the ultrahigh molecular weight component or One end of the main chain of the pseudo ultra-high molecular weight component is constrained by the rotation projecting pin 42, and the other end is constrained by the inner wall surface of the housing recess 32 or the surface of the slide member 34, so that the component is rotated by the rotation projecting pin 42. Therefore, the elongation strain of the melt parts A′2 and A′3 as a whole is promoted starting from the component.

  After the crystallization step, when the mold 11 is cooled to a predetermined temperature, the mold is opened, thereby obtaining a resin molded product whose mechanical strength and heat resistance are partially enhanced by the crystallization. Can do.

  According to this embodiment, in order to realize an elongation strain equal to or higher than the critical elongation strain rate of the crystalline polymer resin material, the torsional force generated by the high-speed rotation of the rotary protruding pin 42 is mainly used, and the required torsional force is applied. Therefore, the rotational speed of the rotation protrusion pin 42 required for this can be obtained relatively easily and reliably by using an inexpensive servo motor or the like. Therefore, as in the first embodiment, it is possible to easily and reliably realize molding with an elongation strain equal to or higher than the critical elongation strain rate of the resin material, and thus with a high crystallinity.

  Further, according to the present embodiment, when the crystalline polymer resin material is stretched at a strain rate equal to or higher than the critical elongation strain rate, in addition to the twisting force, the crystalline polymer resin material is along a direction substantially parallel to the rotational axis of the twisting force. Resin materials are used not only in the extension direction (rotation direction) due to the torsional force but also in the extension direction due to the tensile force (a direction substantially parallel to the axial direction) and in the extension direction due to the compression force (shear direction) because tensile force and compression force are used Can be stretched. Therefore, the elongation strain rate of the resin material can be further increased, and the crystallinity of the resin material can be further improved.

  Furthermore, since the injection process and the crystallization process are continuously performed using a single molding apparatus 30, it is possible to efficiently produce a resin molded product with a partially increased degree of crystallinity. it can.

  In the second embodiment, at least one of the front end surface and the side surface of the rotation projecting pin 42, the surface of the slide member 34, and the inner wall surface of the housing recess 32 is easily adhered to the supercooled resin material. The resin material may be an uneven surface, which makes it easy for the resin material to extend following the rotation and sliding movement of the rotating protrusion pin 42. In this case, the configuration for forming the concavo-convex surface is not limited. For example, a configuration in which a plurality of protrusions are provided as in the first embodiment, or a configuration in which a plurality of grooves are formed, embossing For example, a configuration for performing blasting or a configuration for performing blasting may be employed.

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIGS. Note that in the third embodiment, detailed description of the same configurations as those of the first and second embodiments is omitted.

  FIG. 7 shows a molding apparatus 50 used for molding a resin molded product by the molding method according to the third embodiment. The molding apparatus 50 includes a molding die 51 having a fixed die 52 and a movable die 53.

  The molding surface 52a of the fixed mold 52 is provided with, for example, a circular receiving recess 56, and a disc-shaped slide member 57 is received in the receiving recess 56 so as to close the open end of the receiving recess 56. Has been. One end of a support shaft 58 that passes through the bottom surface of the housing recess 56 is connected to the slide member 57. The other end of the support shaft 58 is connected to a drive source (not shown) for sliding the slide member 57 together with the support shaft 58 in the axial direction. In addition to the receiving recess 56, a plurality of recesses 54 and 55 are provided on the molding surface 52 a of the fixed mold 52.

  On the other hand, the movable die 53 is provided with, for example, a circular through hole 62 at a position facing the housing recess 56, and a rotation projecting pin 63 is fitted into the through hole 62. A base end portion of the rotation projecting pin 63 is connected to a drive source (not shown) for rotating the rotation projecting pin 63 about the axial direction while sliding the rotational projecting pin 63 in the axial direction via the support shaft 64. The distal end portion of the rotation projecting pin 63 can be projected and retracted from the molding surface 53a to the fixed mold 52 side by sliding movement in the axial direction. Further, the molding surface 53a of the movable die 53 is provided with convex portions 60 and 61 at positions facing the plurality of concave portions 54 and 55 of the fixed die 52, respectively, and when the movable die 53 is clamped. The convex portions 60 and 61 and the concave portions 54 and 55 of the fixed mold 52 are engaged with each other (see FIG. 8).

  Next, a method for molding a resin molded product using the molding apparatus 50 will be described.

  As shown in FIG. 7, first, the sheet-like resin material B is placed on the molding surface 52 a of the fixed mold 52. At this time, the surface of the slide member 57 on the movable mold 53 side is flush with the molding surface 52 a of the fixed mold 52, and the tip surface of the rotary protruding pin 63 is flush with the molding surface 53 a of the movable mold 53. Yes.

  As the resin material B, the same resin material as in the first embodiment is used. Further, it is preferable to add an ultrahigh molecular weight component having a main chain having a length comparable to or longer than the thickness of the resin sheet B to the resin material, thereby causing crystallization described later. It becomes easy. Alternatively, in place of the addition of the ultrahigh molecular weight component, a functional group (for example, a carboxyl group and a hydroxyl group) for attracting the ends of the polymer is added, thereby making a pseudo-comprising of a plurality of polymers attracted to each other. An ultrahigh molecular weight component may be formed, and the same effect can be obtained by this.

  Next, the resin material B is heated to a temperature equal to or higher than the melting point by a heater (not shown). However, the sheet-shaped resin material B may be preheated and then placed on the molding surface 52a of the fixed mold 52.

  Subsequently, when the resin material B ′ thus heated is cooled and the temperature falls below the melting point and above the crystallization temperature, that is, at the timing when the resin material B ′ is in a supercooled state, FIG. As shown, the movable mold 53 is clamped and press-molded.

  Simultaneously with the mold clamping, the slide member 57 is slid by the drive source (not shown) toward the bottom surface of the housing recess 56 until it comes into contact with the bottom surface, and the rotation projecting pin 63 is moved by another drive source (not shown). While being rotated at a high speed, it is slid so as to protrude from the molding surface 53a to the fixed mold 52 side. At this time, each slide movement of the slide member 57 and the rotation projecting pin 63 is performed at a speed and timing such that the distance between the members 57 and 63 in the slide direction is gradually reduced from the start of the slide movement to the end of the slide movement.

  At this time, the resin portion B′1 in the vicinity of the side surface of the rotary protruding pin 63 is pulled along the direction substantially parallel to the axial direction of the rotating protruding pin 63 together with the torsional force along the rotating direction of the rotating protruding pin 63. A force is applied and an elongation strain in both directions occurs.

  On the other hand, the resin portion B′2 between the distal end surface of the rotation protrusion pin 63 and the slide member 57 is substantially parallel to the axial direction of the rotation protrusion pin 63 together with the torsional force along the rotation direction of the rotation protrusion pin 63. A compressive force along the direction is applied, and an elongation strain in the rotational direction and the shear direction of the rotary protruding pin 63 is generated.

  The rotation speed of the rotation protrusion pin 63 and the slide movement speed of the rotation protrusion pin 63 and the slide member 57 are set to a speed at which the elongation strain rate of the resin portions B′1 and B′2 is equal to or higher than the critical elongation strain rate. Has been. However, the force causing the elongation strain of the resin parts B′1 and B′2 is mainly the torsional force, and the tensile force or the compressive force plays an auxiliary role. It is important to be fast.

  Through this process, the resin parts B′1 and B′2 are stretched at a speed equal to or higher than the critical elongation strain rate, and the entangled polymer chain is stretched to become an aligned melt aligned in parallel and crystallized. Numerous nuclei are formed in the resin parts B′1 and B′2 and thereafter crystallization occurs in a short time and at a very high rate.

  In addition, as described above, if an ultrahigh molecular weight component is added to the resin material B in advance, or if a functional group for forming a pseudo ultrahigh molecular weight component is added, the ultrahigh molecular weight component or One end of the main chain of the pseudo ultra-high molecular weight component is constrained by the rotation projecting pin 63 and the other end is constrained by the inner wall surface of the accommodating recess 56 or the surface of the slide member 57, so that the component becomes the rotation projecting pin 63. Therefore, the strain of the resin portions B′1 and B′2 as a whole is promoted from the starting point.

  After the press molding, the mold 51 is opened when the mold 51 is cooled to a predetermined temperature, whereby a resin molded product having partially enhanced mechanical strength, heat resistance, etc. can be obtained by the above crystallization. .

  According to this embodiment, in order to realize an elongation strain equal to or higher than the critical elongation strain rate of the crystalline polymer resin material, the torsional force generated by the high-speed rotation of the rotary protruding pin 63 is mainly used, and the required torsional force is applied. Therefore, the rotational speed of the rotation protrusion pin 63 required for this can be obtained relatively easily and reliably by using an inexpensive servo motor or the like. Therefore, as in the first and second embodiments, it is possible to easily and reliably realize the molding with an elongation strain higher than the critical elongation strain rate of the resin material, and thus with a high degree of crystallinity.

  Further, according to the present embodiment, as in the second embodiment, in addition to the torsional force, a tensile force and a compressive force along a direction substantially parallel to the rotational axis of the torsional force are used. The elongation strain rate can be further increased, and the crystallinity of the resin material can be further improved.

  In the third embodiment, at least one of the front end surface and the side surface of the rotation projecting pin 63, the surface of the slide member 57, and the inner wall surface of the housing recess 56 is likely to be in close contact with the supercooled resin material. The resin material may be an uneven surface, which makes it easy for the resin material to extend following the rotation and sliding movement of the rotating protrusion pin 63. In this case, the configuration for forming the concavo-convex surface is not limited. For example, a configuration in which a plurality of protrusions are provided as in the first embodiment, or a configuration in which a plurality of grooves are formed, embossing For example, a configuration for performing blasting or a configuration for performing blasting may be employed.

[Fourth Embodiment]
A fourth embodiment of the present invention will be described with reference to FIGS. Note that in the fourth embodiment, detailed description of the same configurations as those of the first to third embodiments will be omitted.

  FIG. 9 shows a molding apparatus 70 used for molding a resin molded product by the molding method according to the fourth embodiment. The molding apparatus 70 is used for post-processing a resin molded product C molded by injection molding, for example, and has a molding die 71 having a fixed die 72 and a movable die 73.

  The molding surface 72a of the fixed mold 72 is provided with, for example, a circular receiving recess 76, and a disc-shaped slide member 77 is received in the receiving recess 76 so as to close the open end of the receiving recess 76. Has been. One end of a support shaft 78 that passes through the bottom surface of the housing recess 76 is connected to the slide member 77. The other end of the support shaft 78 is connected to a drive source (not shown) for sliding the slide member 77 together with the support shaft 78 in the axial direction.

  On the other hand, the movable mold 73 is provided with, for example, a circular through hole 80 at a position facing the accommodation recess 76, and a rotation projecting pin 82 is fitted into the through hole 80. The base end portion of the rotation projecting pin 82 is connected via a support shaft 82 to a drive source (not shown) for rotating the rotation projecting pin 82 about the axial direction while sliding the rotational projecting pin 82 in the axial direction. The distal end portion of the rotary protruding pin 82 can be projected and retracted from the molding surface 73a toward the fixed die 72 by sliding in the axial direction.

  Next, a method for molding a resin molded product using the molding apparatus 70 will be described.

  As shown in FIG. 9, first, for example, a sheet-shaped resin molded product C molded in advance by, for example, injection molding is placed on the molding surface 72 a of the fixed mold 72. At this time, the surface of the slide member 77 on the movable mold 73 side is flush with the molding surface 72 a of the fixed mold 72, and the distal end surface of the rotary protruding pin 82 is flush with the molding surface 73 a of the movable mold 73. Yes.

  As the material of the resin molded product C, the same resin material as in the first embodiment is used. In addition, it is preferable to add an ultrahigh molecular weight component having a main chain having a length comparable to or longer than the thickness of the resin molded product C to the resin material. It tends to happen. Alternatively, in place of the addition of the ultrahigh molecular weight component, a functional group (for example, a carboxyl group and a hydroxyl group) for attracting the ends of the polymer is added, thereby making a pseudo-comprising of a plurality of polymers attracted to each other. An ultrahigh molecular weight component may be formed, and the same effect can be obtained by this.

  Next, the resin molded product C is heated by a heater (not shown) at least in the upper part of the slide member 77 until the temperature reaches the melting point or higher.

  Subsequently, when the heated portion C′1 of the resin molded product C is cooled and the temperature is lowered to the melting point or lower and the crystallization temperature or higher, that is, the heated portion C′1 of the resin molded product C is in an overcooled state. At this timing, the movable mold 73 is clamped so that the heating portion C′1 of the resin molded product C is sandwiched between the molding surface 72a of the fixed mold 72 and the molding surface 73a of the movable mold 73.

  Simultaneously with the mold clamping, the slide member 77 is slid by the drive source (not shown) toward the bottom surface of the housing recess 76 until it comes into contact with the bottom surface, and the rotation projecting pin 82 is moved by another drive source (not shown). While being rotated at a high speed, it is slid so as to protrude from the molding surface 73a to the fixed mold 72 side. At this time, each slide movement of the slide member 77 and the rotation projecting pin 82 is performed at such a speed and timing that the distance between the both members 77 and 82 in the slide direction is gradually reduced from the start of the slide movement to the end of the slide movement.

  At this time, the resin portion C ′ 2 near the side surface of the rotary protruding pin 82 is pulled along the direction substantially parallel to the axial direction of the rotating protruding pin 82 together with the torsional force along the rotating direction of the rotating protruding pin 82. A force is applied and an elongation strain in both directions occurs.

  On the other hand, the resin portion C ′ 3 between the distal end surface of the rotation protrusion pin 82 and the slide member 77 is substantially parallel to the axial direction of the rotation protrusion pin 82 together with the torsional force along the rotation direction of the rotation protrusion pin 82. A compressive force along the direction is applied, and an elongation strain in the rotational direction and shear direction of the rotary protruding pin 82 is generated.

  The rotation speed of the rotation protrusion pin 82 and the slide movement speed of the rotation protrusion pin 82 and the slide member 77 are set to a speed at which the elongation strain rate of the resin portions C′2 and C′3 is equal to or higher than the critical elongation strain rate. Has been. However, the force causing the elongation strain of the resin portions C′2 and C′3 is mainly the torsional force, and the tensile force or the compressive force plays an auxiliary role. It is important to be fast.

  Through this process, the resin portions C′2 and C′3 are stretched at a speed equal to or higher than the critical elongation strain rate, and the entangled polymer chain is stretched to become an aligned melt aligned in parallel and crystallized. Numerous nuclei are formed in the resin portions C′2 and C′3, and thereafter, crystallization occurs in a short time and at a very high rate.

  Further, as described above, if an ultrahigh molecular weight component is added to a resin material in advance or a functional group for forming a pseudo ultrahigh molecular weight component is added, the ultrahigh molecular weight component or pseudo One end of the main chain of a typical ultra-high molecular weight component is constrained by the rotation projecting pin 82, and the other end is constrained by the inner wall surface of the accommodating recess 76 or the surface of the slide member 77. Since it becomes easy to extend following the rotation and slide movement, the elongation strain of the entire resin portions C′2 and C′3 is promoted starting from the component.

  After the press molding, when the mold 71 is cooled to a predetermined temperature, the mold is opened, thereby obtaining a resin molded product C partially improved in mechanical strength, heat resistance, etc. by the above crystallization. it can.

  According to this embodiment, in order to realize an elongation strain equal to or higher than the critical elongation strain rate of the crystalline polymer resin material, the torsional force generated by the high-speed rotation of the rotary protruding pin 82 is mainly used, and the required torsional force is applied. Therefore, the rotational speed of the rotation protrusion pin 82 required for this can be obtained relatively easily and reliably by using an inexpensive servo motor or the like. Therefore, as in the first to third embodiments, it is possible to easily and reliably realize the elongation strain equal to or higher than the critical elongation strain rate of the resin material, and thus molding at a high crystallinity.

  Further, according to the present embodiment, as in the second and third embodiments, in addition to the torsional force, a tensile force and a compressive force along a direction substantially parallel to the rotational axis of the torsional force are used. The elongation strain rate of the resin material can be further increased, and the crystallinity of the resin material can be further improved.

  In the fourth embodiment, at least one of the front end surface and the side surface of the rotation projecting pin 82, the surface of the slide member 77, and the inner wall surface of the housing recess 76 is likely to be in close contact with the supercooled resin material. The resin material may be an uneven surface, which makes it easy for the resin material to extend following the rotation and sliding movement of the rotary projecting pin 82. In this case, the configuration for forming the concavo-convex surface is not limited. For example, a configuration in which a plurality of protrusions are provided as in the first embodiment, or a configuration in which a plurality of grooves are formed, embossing For example, a configuration for performing blasting or a configuration for performing blasting may be employed.

[Fifth Embodiment]
A fifth embodiment of the present invention will be described with reference to FIGS. Note that in the fifth embodiment, detailed description of the same configurations as those of the first to fourth embodiments is omitted. 11 to 17, members having the same functions as those in the first embodiment are denoted by the same reference numerals.

  FIG. 11 shows a molding apparatus 90 used for molding a resin molded product by the molding method according to the fifth embodiment. The molding device 90 includes a molding die 91 having a fixed die 92 and a movable die 93, and an injection device 16 for injecting a resin melt into a cavity 95 surrounded by the fixed die 92 and the movable die 93.

  The fixed die 92 of the molding die 91 is provided with an injection passage 98 communicating with the surface constituting the cavity 95, that is, the molding surface 92a and the exposed surface 92b to the outside, and the injection device 16 passes through the injection passage 98. The injected melt is guided to the cavity 95. The molding surface 92a of the fixed die 92 is provided with a recess 96 for avoiding interference with the rotating body 100 described later.

  On the other hand, the molding surface of the movable die 93 includes a facing surface 93a facing the molding surface 92a of the fixed die 92, and a cylindrical inner peripheral surface 93b extending from the periphery of the facing surface 93a toward the periphery of the molding surface 92a of the fixed die 92. And have. The cylindrical inner peripheral surface 93b is provided with a plurality of protrusions 104 extending in the axial direction of the cylindrical inner peripheral surface 93b. As shown in FIG. 12, the ridges 104 are arranged without gaps over the entire circumference of the cylindrical inner peripheral surface 93b, and each ridge 104 is formed in, for example, a triangular cross section. Since the protruding portion 104 is provided in this way, the cylindrical inner peripheral surface 93b is an uneven surface as a whole, and thus the cylindrical inner peripheral surface 93b is in a supercooled state as described later. As a result, the resin material in the cavity 95 whose viscosity has increased is easily adhered.

  However, the extending direction, arrangement, and cross-sectional shape of the protrusion 104 are not limited to the above configuration. For example, the protrusion 104 is inclined in the direction inclined with respect to the axial direction of the cylindrical inner peripheral surface 93b. It may be extended. Further, as a configuration for making the cylindrical inner peripheral surface 93b an uneven surface, a configuration other than the configuration in which the protrusion 104 is provided may be adopted. For example, a plurality of grooves are formed in the cylindrical inner peripheral surface 93b. Alternatively, the concave and convex portions may be formed on the cylindrical inner peripheral surface 93b by performing a texture process or a blast process.

  Further, as shown in FIG. 11, a disk-like rotating body 100 is rotatably attached to the facing surface 93 a of the movable mold 93, so that the cavity 95 has a ring shape surrounding the rotating body 100. It has become a space. In a state where the mold is clamped, most of the rotating body 100 is accommodated in the concave portion 96 of the fixed mold 92.

  At the center of the rotating body 100, for example, the tip of a rotating shaft 108 connected to a driving source such as a motor (not shown) is connected. When the rotating shaft 108 is rotationally driven by the driving source, the rotating shaft 108 rotates. Together with the shaft 108, the rotating body 100 is driven to rotate about the rotating shaft 108. The rotating shaft 108 is provided through the movable mold 93.

  As shown in FIG. 11, the configuration of the injection device 16 is the same as that of the first embodiment. The cylinder 16 a of the injection device 16 is attached to the fixed mold 92 so that the discharge port 16 c is connected to one end of the injection passage 98 provided in the fixed mold 92.

  The cylinder 16a is connected to a foaming agent supply unit 120 that supplies a physical foaming agent into the cylinder 16a. Carbon dioxide or nitrogen is preferably used as the physical foaming agent, but the type of physical foaming agent used in the present invention is not limited to these.

  The blowing agent supply unit 120 includes a cylinder 122 that contains an inert gas such as carbon dioxide or nitrogen, and a blowing agent generator that generates a physical blowing agent by a known method using the inert gas supplied from the cylinder 122 as a raw material. 124 and a supply nozzle 126 for supplying the physical foaming agent generated by the generating device 124 into the cylinder 16a. The physical foaming agent supplied from the supply nozzle 126 into the cylinder 16a is dissolved in the resin melt in the cylinder 16a. Thereby, the resin melt in the cylinder 16a is injected into the cavity 95 of the mold 91 in a state containing the physical foaming agent.

  However, in this embodiment, a chemical foaming agent may be used instead of the physical foaming agent. In this case, the chemical foaming agent is supplied into the cylinder 16a through the hopper 16b.

  As the resin material, the same resin material A as in the first embodiment is used. In addition, it is preferable to add an ultrahigh molecular weight component having a main chain having a length equal to or longer than the interval between the outer peripheral surface of the rotating body 100 and the cylindrical inner peripheral surface 93b to the resin material. Therefore, the crystallization described later is likely to occur. Alternatively, in place of the addition of the ultrahigh molecular weight component, a functional group (for example, a carboxyl group and a hydroxyl group) for attracting the ends of the polymer is added, thereby making a pseudo-comprising of a plurality of polymers attracted to each other. An ultrahigh molecular weight component may be formed, and the same effect can be obtained by this.

  Next, a method for molding a resin molded product using the molding apparatus 90 will be described.

  As shown in FIG. 11, first, the mold 91 is clamped by a mold opening / closing device (not shown). In parallel with this, the solid crystalline polymer resin material A is put into the hopper 16b of the injection device 16, and the screw 16d is operated in the cylinder 16a to heat the resin material A to the melting point or higher. In addition to obtaining melt A ′ by melting, a physical foaming agent is supplied from the foaming agent supply unit 120 into the cylinder 16a, and the physical foaming agent is dissolved in the melt A ′.

  Next, as shown in FIG. 13, as the injection process, the melt A ′ is injected and filled into the cavity 95 by the injection device 16.

  Subsequently, as shown in FIG. 14, as the first core back process, the temperature of the melt A ′ of the crystalline polymer resin filled in the cavity 95 ′ is not higher than the melting point and not lower than the crystallization temperature. Immediately before cooling, that is, immediately before the melt A ′ becomes supercooled, as shown in FIG. 14, a mold opening / closing device (not shown) is operated to move the movable mold 93 away from the fixed mold 92. Core back in the direction. As a result, the volume of the cavity 95 'increases, and the polymer resin in the cavity 95' is molded while being foamed.

  Further, during the first core back step, the melt A ′ in the cavity 95 is further cooled and becomes a supercooled state, and as shown in FIG. 15, the first crystallization step is not shown. The rotating body 100 is rotationally driven at a high speed together with the rotating shaft 108 by a driving source. As a result, a torsional force along the rotational direction of the rotating body 100 is applied to the melt A ′ in the cavity 95, and elongation strain along the rotational direction is generated.

  The rotation speed of the rotating body 100 is set to a speed at which the elongation strain rate of the melt A ′ is equal to or higher than the critical elongation strain rate. Therefore, by the rotation of the rotating body 100, the melt A ′ is stretched at a speed equal to or higher than the critical elongation strain rate, and the entangled polymer chain is stretched to become an aligned melt aligned in parallel and crystallized. Numerous nuclei serving as the base point of are formed in the melt A ′, and thereafter, crystallization occurs in a short time and at a very high rate. Since this crystallization occurs in a very short time, the rotation driving time of the rotating body 100 may be extremely short.

  In addition, as described above, if an ultrahigh molecular weight component is added to the resin material A in advance or a functional group for forming a pseudo ultrahigh molecular weight component is added, the ultrahigh molecular weight component or One end of the main chain of the pseudo ultra-high molecular weight component is constrained to the outer peripheral surface of the rotating body 100, and the other end is constrained to the cylindrical inner peripheral surface 93b, so that the component follows the rotation of the rotating body 100. Therefore, the elongation strain of the entire melt A ′ is promoted starting from the component.

  Further, when the rotating body 100 is driven to rotate, a tensile force in the core back direction is applied to the melt A ′ in the cavity 95 along with the core back of the movable mold 93. In addition to the elongation strain, the elongation strain in a direction substantially parallel to the axial direction of the rotating body 100 also occurs. Therefore, the elongation strain of the melt A ′ is further promoted.

  If the thickness of the resin A′4 crystallized in the cavity 95 does not reach the predetermined thickness at the completion of the first crystallization step, the second core back step is continued as shown in FIG. Run. In the second core back step, injection from the cylinder 16a into the cavity 95 and the core back of the movable mold 93 are performed in parallel, and the melt A′5 in the cavity 95 is cooled during the core back. As shown in FIG. 17, at the timing when the supercooling state is reached, the rotating body 100 is again rotated at a high speed as the second crystallization step. As a result, the melt A′5 newly supplied into the cavity 95 in the second core back step is applied with a torsional force along the rotational direction of the rotating body 100, so that the melt A′5 extends in the rotational direction. Along with the occurrence of strain, a tensile force accompanying the core back is also applied, so that an extension strain in the core back direction also occurs. Therefore, like the first crystallization step, the melt A′5 is stretched at a rate equal to or higher than the critical elongation strain rate and crystallized in a short time and at a very high rate.

  By repeating such a series of steps, when the thickness of the resin A′4, A′5,... Crystallized in the cavity 95 reaches a predetermined thickness, the mold 91 is cooled to a predetermined temperature. By performing mold opening, a resin molded product with a high crystallinity having excellent mechanical strength and heat resistance can be obtained.

  According to this embodiment, in order to realize an elongation strain equal to or higher than the critical elongation strain rate of the crystalline polymer resin material, the torsional force generated by the high-speed rotation of the rotating body 100 is used, and the required torsional force is applied. The necessary rotational speed of the rotating body 100 can be obtained relatively easily and reliably by using an inexpensive servo motor or the like. Therefore, as in the first to fourth embodiments, it is possible to easily and reliably realize the elongation strain higher than the critical elongation strain rate of the resin material, and thus molding with a high degree of crystallinity.

  Further, according to the present embodiment, as in the second to fourth embodiments, in addition to the torsional force, a tensile force along a direction substantially parallel to the rotational axis of the torsional force is used. The elongation strain rate can be further increased, and the crystallinity of the resin material can be further improved.

  Furthermore, since the injection process, the core back process, and the crystallization process are continuously performed using a single molding apparatus 90, a resin molded product having a high crystallinity can be efficiently produced.

  Furthermore, according to this embodiment, since foaming is used for strain extension of the polymer resin melt A ′, a molded product having a high degree of crystallinity can be obtained while being a foam. Therefore, it is possible to obtain a molded product having the characteristics of a resin foam excellent in light weight, heat insulation, shock absorption, and the like, and the characteristics of a polymer crystal excellent in mechanical strength and heat resistance.

[Sixth Embodiment]
A sixth embodiment of the present invention will be described with reference to FIG. Note that in the sixth embodiment, detailed description of the same configurations as those of the first to fifth embodiments will be omitted.

  FIG. 18 shows a molding apparatus 130 used for molding a resin molded product by the molding method according to the sixth embodiment. The molding apparatus 130 includes a press mold 131 having a fixed mold 132 and a movable mold 133.

  The movable mold 133 is connected to a drive source (not shown) via a support shaft 138, and is driven by the drive source so as to move in the press direction while rotating around the axial direction of the support shaft 138. It has become.

  A plurality of protrusions 134 and 136 are provided on the molding surface 132a of the fixed mold 132 and the molding surface 133a of the movable mold 133, respectively. These protrusions 134 and 136 are formed, for example, in a triangular cross section, and extend radially from the centers of the molding surfaces 132a and 133a. Since the molding surfaces 132a and 133a are uneven as a whole due to the provision of the protrusions 134 and 136, the molding surfaces 134 and 136 are brought into a supercooled state as described later. The resin material having increased viscosity is easily adhered.

  However, the extending direction, arrangement, and cross-sectional shape of the protrusions 134 and 136 are not limited to the above configuration. Further, as a configuration for making the molding surfaces 132a and 133a uneven, a configuration other than the configuration in which the protrusions 134 and 136 are provided may be employed. For example, a plurality of grooves are formed in the molding surfaces 132a and 133a. However, unevenness may be formed on the molding surfaces 132a and 133a by applying a texture process, a texture process, or a blast process.

  Next, a method for molding a resin molded product using the molding apparatus 130 will be described.

  As shown in FIG. 18, first, a sheet-like resin material D is placed on the molding surface 132 a of the fixed mold 132. As the resin material D, the same resin material as in the first embodiment is used. In addition, it is preferable to add an ultrahigh molecular weight component having a main chain having a length comparable to or longer than the thickness of the resin material, whereby crystallization described later easily occurs. Become. Alternatively, in place of the addition of the ultrahigh molecular weight component, a functional group (for example, a carboxyl group and a hydroxyl group) for attracting the ends of the polymer is added, thereby making a pseudo-comprising of a plurality of polymers attracted to each other. An ultrahigh molecular weight component may be formed, and the same effect can be obtained by this.

  Next, the resin material D is heated to a temperature equal to or higher than the melting point by a heater (not shown). However, the sheet-shaped resin material D may be preliminarily heated and then placed on the molding surface 132a of the fixed mold 132.

  Subsequently, when the resin material D is cooled and the temperature drops below the melting point and above the crystallization temperature, that is, at the timing when the resin material D is in a supercooled state, the mold is clamped while rotating the movable mold 133 and pressed. Mold.

  Thereby, torsional force along the rotation direction of the movable mold 133 is applied to the resin material D, and elongation strain in the rotation direction is generated.

  The rotational speed of the movable mold 133 is set to a speed at which the elongation strain rate of the resin material D is equal to or higher than the critical elongation strain rate. As a result, the resin material D is stretched at a speed equal to or higher than the critical elongation strain rate, the entangled polymer chain is stretched to become an aligned melt aligned in parallel, and the nucleus serving as the crystallization base point is the resin material. Many are formed in D, and then crystallization occurs in a short time and at a very high rate.

  In addition, as described above, if an ultrahigh molecular weight component is added to the resin material D in advance or a functional group for forming a pseudo ultrahigh molecular weight component is added, the ultrahigh molecular weight component or One end of the pseudo-high molecular weight component main chain is constrained to the molding surface 132a of the fixed mold 132 and the other end is constrained to the molding surface 133a of the movable mold 133, so that the component is rotated by the movable mold 133. Since it tends to follow and extend, extension strain of the whole resin material D is promoted starting from the component.

  After the press molding, when the mold 131 is cooled to a predetermined temperature, the mold is opened, whereby a resin molded article having improved mechanical strength, heat resistance and the like can be obtained by the crystallization.

  According to this embodiment, in order to realize an elongation strain higher than the critical elongation strain rate of the crystalline polymer resin material, the torsional force generated by the high-speed rotation of the movable mold 133 is used, and the required torsional force is applied. The necessary rotational speed of the movable mold 133 can be obtained relatively easily and reliably by using an inexpensive servo motor or the like. Therefore, as in the first to fifth embodiments, it is possible to easily and reliably realize the elongation strain higher than the critical elongation strain rate of the resin material, and thus molding at a high crystallinity.

  As mentioned above, each shaping | molding method which concerns on 1st-6th embodiment can be applied to shaping | molding of all the parts made from resin, or a part of parts, Specifically, for example, the boss | hub part of various automobile parts Or it is applied suitably for shaping | molding of a fastening seat surface part, or a spare tire cover or a spare tire pan.

  Although the present invention has been described with reference to the above embodiment, the present invention is critically stretched by applying a torsional force to the supercooled crystalline polymer resin material in the mold. If it is the structure shape | molded so that it may be made to extend | stretch and crystallize at the strain rate more than a strain rate, it will not be limited to the above-mentioned embodiment.

  Furthermore, in any embodiment other than the above-described embodiment, when the resin material is stretched at a strain rate equal to or higher than the critical elongation strain rate, the tensile force along the direction substantially parallel to the rotational axis of the torsion force is provided together with the torsion force. It is preferable to apply at least one of a force and a compressive force, whereby the resin material can be more effectively extended.

  Finally, an example in which molding is performed by the method according to the first embodiment will be described.

  In this example, a crystalline polymer resin material is manufactured using the same apparatus as the molding apparatus 10 according to the first embodiment provided with a molding die having a clamping force of 220 tons and an injection apparatus manufactured by Nippon Steel Works. The polypropylene resin material (trade name: Novatec) manufactured by Nippon Polypro Co., Ltd. was used.

Then, the melting temperature of the resin material in the injection apparatus is set to 180 ° C., the mold temperature is set to 150 ° C., and the crystalline polymer resin material is melted at about 134 cm ³ from the cylinder of the injection apparatus into the mold cavity that is clamped. The liquid was slowly injected and filled. Then, it waited for about 10 seconds until the temperature of this melt fell to about 160 degreeC. This temperature was lower than the melting point of the resin and higher than the crystallization temperature, which caused the melt to be supercooled.

  When the waiting for about 10 seconds was completed, the rotating body 20 was rotated at 600 rpm. Then, after cooling until the mold temperature became 80 ° C. or lower, the mold was opened, and a resin molded product having a plate thickness of about 3 mm was taken out.

  When the strength of the central part of the molded product was measured, it was confirmed that the molded product had a desired high mechanical strength.

  As described above, since the molded product obtained by the present invention has the characteristics of a polymer crystal having excellent mechanical strength, heat resistance, etc., such a technology is required, for example, manufacturing technology for automobile parts and the like. It may be suitably used in the field.

10, 30, 50, 70, 90, 130: Molding device, 11, 51, 71, 91, 131: Mold, 20, 100: Rotating body, 34, 57, 77: Slide member, 42, 63, 82: Rotating protrusion pin, 132: fixed type, 133: movable type.

Claims (4)

  In the mold, the resin material is stretched at a strain rate equal to or higher than the critical elongation strain rate by applying a twisting force to the crystalline polymer resin material having a temperature equal to or lower than the melting point and equal to or higher than the crystallization temperature. A method for molding a resin molded product, characterized by molding so as to crystallize through a state.   When the resin material is stretched at a strain rate equal to or higher than a critical elongation strain rate, at least one of a tensile force and a compressive force along a direction substantially parallel to the rotational axis of the torsional force is applied together with the torsional force. The method for molding a resin molded product according to claim 1.   The method for molding a resin molded product according to claim 1, wherein the resin material is a general-purpose plastic.   The method for molding a resin molded product according to claim 3, wherein the general-purpose plastic is polypropylene.

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