JP2005335243A - Resin molding component for chair and method for producing resin molding component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure strength and to have flexibility while improving appearance quality. <P>SOLUTION: A component is exposed while being attached to a chair 2 and has a core layer 3 of a synthetic resin material incorporated with a reinforcement and a skin layer 4 of a synthetic resin material without the reinforcement. The periphery of the core layer 3 is covered with the skin layer 4, In the component, the ratio of the core layer 3 is enlarged in proportion to the increase of required strength. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin molded part for a chair and a method for producing the resin molded part. More specifically, the present invention relates to a resin molded part for a chair in which a core layer having high strength is covered with a skin layer having excellent appearance quality, and a method for producing the resin molded part.

  As a resin molded product composed of a core layer and a skin layer, there is one disclosed in JP-A-2002-120255. This resin molded product is obtained by crushing a discarded thermosetting resin and mixing it with a thermoplastic resin to form a core layer, and a thermoplastic resin compatible with the thermoplastic resin in the core layer. The skin layer. Due to the compatibility problem between the thermosetting resin and the thermoplastic resin, the appearance quality of the core layer is poor and the strength is also weak. For this reason, while covering the core layer with a skin layer having excellent appearance quality, the appearance quality as a resin molded product is improved, and by integrating the thermoplastic resins of the core layer and the skin layer as a resin molded product, Ensuring strength. Since the thing discarded as the thermosetting resin of a core layer is recycled, it can aim at the effective use of resources and is meaningful.

JP 2002-120255 A

  However, although the strength of the resin molded product described above is secured by covering the core layer with a skin layer, the strength is insufficient particularly when applied to a plate-like component. In other words, the above-mentioned resin molded product is intended to recycle the thermosetting resin, and is merely intended to make up for the accompanying lack of strength of the core layer with the skin layer. It is not intended to increase strength.

  In addition, the resin molded parts that are exposed when assembled as a chair, in addition to ensuring the appearance quality and the parts strength, in addition to the flexibility, it also has a flexibility that gives the seat a fit. is necessary. However, in the above-mentioned resin molded product, it is difficult to ensure the strength and flexibility as a component of the chair, even though the appearance quality can be ensured.

  An object of the present invention is to provide a resin molded part for a chair capable of ensuring further strength while improving the appearance quality, and a method for producing a resin molded part suitable for the production thereof. Another object of the present invention is to provide a resin molded part for a chair having a bendability that improves sitting comfort and a method for producing a resin molded part suitable for the production thereof.

  In order to achieve such an object, a resin molded part for a chair according to claim 1 includes a core layer made of a synthetic resin material mixed with a reinforcing material, and a skin layer made of a synthetic resin material not mixed with a reinforcing material. The core layer is covered with a skin layer.

  A reinforcing material is mixed in the synthetic resin of the core layer, and the strength of the core layer is high, but the appearance quality is inferior because the reinforcing material is exposed on the surface. On the other hand, since the reinforcing material is not mixed in the synthetic resin material of the skin layer, the reinforcing material is not exposed on the surface and the appearance quality is excellent. Rather than forming all the resin molded parts for chairs with a skin layer, the core layer having a high strength is provided in the skin layer, so that the strength as a resin molded part for chairs can be further increased.

  Moreover, the resin molded part for a chair according to claim 2 has a higher proportion of the core layer as the required strength is higher. Therefore, it is possible to increase the strength of only the necessary parts and ensure the flexibility at the other parts.

  Moreover, the resin molded part for chairs of Claim 3 is exposed in the state assembled | attached to the chair. The skin layer covers the periphery of the core layer so that the appearance quality as a part to be used can be ensured.

  The resin molded part for a chair according to claim 4 is used as the back of the chair, and the lower layer and the mounting portion to the chair body have a higher proportion of the core layer than the upper part.

  When the seated person leans against the back of the chair, the seated person's back mainly hits the upper back of the chair and knocks it down, so a load acts mainly on the upper back of the chair, and it is mainly attached to the lower back and chair body. Bending stress concentrates on the part. The spine is composed of a core layer and a skin layer, but the ratio of the core layer is higher in the lower part and the attachment part to the chair body than in the upper part of the back, so the strength of the part where bending stress is concentrated Can be increased, and the portion of the seated person hitting the back can be softened.

  Furthermore, the invention according to claim 5 is a mold for molding the core material and the skin material so that the core material made of the synthetic resin mixed with the reinforcing material is covered with the skin material made of the synthetic resin not mixed with the reinforcing material. In the method of manufacturing a resin molded part to be filled in the product cavity, the steps of filling the core material and the skin material into the mold are the first injection step of injecting only the skin material, and the skin material after the first injection step. And a second injection step of injecting the core material, and a third injection step of injecting only the skin material after the second injection step, and the material injected in the first and second injection steps of the mold It reaches the product cavity, and the material injected in the third injection process reaches the sprue or gate of the molding die, and from the mixed portion of the core material and skin material to the core material only portion in the sprue or gate of the molding die. Migrate It is intended.

  Accordingly, in the step of filling the molding die with the material, first, the first injection step is performed, and only the skin material is injected. Next, the second injection process is performed to inject the skin material and the core material, and then the third injection process is performed to inject only the skin material. In other words, the material filling is a cycle of skin material → skin material and core material → skin material, and only the skin material is injected at the beginning and end of one cycle, so the next one cycle is repeated as it is after the end of one cycle. be able to.

  At this time, if the skin material injected in the third injection process reaches the product cavity, only the skin material is filled in the product cavity near the gate. Cannot be mixed material. However, in the present invention, the skin material injected in the third injection process does not reach the product cavity, but only reaches the sprue or gate in front of the product cavity. Material and skin material can be mixed.

  Thus, the resin molded part for a chair according to claim 1 comprises a core layer made of a synthetic resin material mixed with a reinforcing material and a skin layer made of a synthetic resin material not mixed with the reinforcing material, Since the periphery of is covered with a skin layer, the strength as a part can be further increased by the core layer.

  Moreover, in the resin molded part for a chair according to claim 2, since the ratio of the core layer is larger as the required strength is higher, only the required part is made stronger and the flexibility is ensured in other parts. Can do.

  The resin molded part for a chair according to claim 3 is a part that is exposed in a state assembled to the chair. Since the skin layer covers the periphery of the core layer, and the skin layer forms the surface, it is possible to ensure the appearance quality as a part that is exposed and used.

  Further, in the resin molded part for a chair according to claim 4, since it is used as the back of the chair and the ratio of the core layer is larger in the lower part and the attachment part to the chair body than in the upper part, the bending stress is increased. The strength of the concentrated portion can be increased, and the portion that the seated person touches can be softened. For this reason, it is possible to give the seated person a sense of security by ensuring rigidity and a feeling of fit by ensuring flexibility, and the sitting comfort of the chair can be improved.

  Furthermore, in the method of manufacturing a resin molded part according to claim 5, the step of filling the molding material with the core material and the skin material includes a first injection step of injecting only the skin material, and a skin after the first injection step. A second injection step of injecting the material and the core material, and a third injection step of injecting only the skin material after the second injection step, and molding the material injected in the first and second injection steps The material injected in the third injection step is made to reach the sprue or gate of the molding die, and only the core material from the mixed portion of the core material and skin material in the sprue or gate of the molding die. Therefore, the filling of the material becomes a cycle of skin material → skin material and core material → skin material, and the first and last of one cycle can be the injection of skin material only, so one cycle ends. , It can be carried out as it is repeated the next one cycle. For this reason, the productivity of resin molded parts can be improved. In the third injection process, the injected skin material does not reach the product cavity, but only reaches the sprue or gate in front of the product cavity. Can be mixed. For this reason, the intensity | strength in the site | parts near the gate of the manufactured resin molded component can be improved.

  Hereinafter, the configuration of the present invention will be described in detail based on the best mode shown in the drawings.

  1 to 3 show an example of an embodiment of a resin molded part for a chair according to the present invention. The resin molded part 1 for a chair is a part that is exposed in a state where it is assembled to the chair 2, and is made of a core layer 3 made of a synthetic resin material mixed with a reinforcing material and a synthetic resin material not mixed with a reinforcing material. The skin layer 4 is provided, the periphery of the core layer 3 is covered with the skin layer 4, and the proportion of the core layer 3 increases as the required strength increases. In this embodiment, the resin molded part 1 for a chair is a part used as the back of the chair 2 (hereinafter referred to as the back 1 as appropriate), and the proportion of the core layer 3 is lower than the upper part 1a and the chair body (this embodiment). The number of attachment portions 1c to the frame) 5 is larger. Here, the ratio of the core layer 3 refers to the ratio of the core layer 3 with respect to the total of the core layer 3 and the skin layer 4 constituting the target site. The higher the required strength, the greater the proportion of the core layer 3 than the other required low strength portions.

  The synthetic resin material of the skin material 6 constituting the skin layer 4 and the synthetic resin material of the core material 7 constituting the core layer 3 may be, for example, a thermoplastic resin or a thermosetting resin. It is preferable to use a material, and it is preferable to use a thermoplastic resin. For example, when polypropylene is used as the skin material 6, polypropylene is also used for the core material 7, and when polyamide is used as the skin material 6, it is preferable to use polyamide for the core material 7. However, it goes without saying that the present invention is not limited to these resins. The reinforcing material mixed in the core material 7 is, for example, glass fiber, talc, mineral, carbon fiber, boron fiber, or the like. That is, the core material 7 is, for example, a reinforced resin such as FRP, and the strength of the core layer 3 is large, but the appearance quality of the core layer 3 is inferior because the reinforcing material is exposed on the surface. On the other hand, the skin layer 4 is excellent in appearance quality including good touch feeling.

  A groove 8 extending in the width direction is formed at the lower end of the spine 1. A backing plate 9 is inserted into the groove 8 and the mounting portion 1 c is sandwiched between the chair 5 and the frame 5. The back 1 is fixed to the frame 5 by screwing a mounting screw (not shown) into the backing plate 9. The spine 1 is used as it is without being covered with a skin member or the like.

  The back 1 as a resin molded part for a chair is manufactured by, for example, an MMP (Mold Master Plate) injection molding method (sandwich molding method), a two-color injection molding method, or the like. An example is shown in FIG. The core layer injection machine 10 and the skin layer injection machine 11 are respectively attached to the molding die 12. Between each of these injection machines 10 and 11 and the mold 12, a double ring adapter 13 having a tip 13 a connected to the injection port 12 a of the mold 12 is arranged. The skin layer injector 11 is connected to the base end 14 a of the portion 14, and the core layer injector 10 is connected to the base end 15 a of the inner ring portion 15. When only the skin layer injection machine 11 of the two injection machines 10 and 11 is operated, only the skin material 6 is injected into the injection port 12a. When the two injection machines 10 and 11 are operated simultaneously, the skin material 6 and the core material 7 are simultaneously injected into the injection port 12a. At this time, the skin material 6 passes through the outer ring portion 14, and the core material 7 passes through the inner ring portion 15. Therefore, the skin material 6 and the core material 7 are centered on the core material 7, and the periphery thereof is the skin material 6. Is injected to cover. That is, the core material 7 and the skin material 6 are filled in the product cavity 12 g of the mold 12 so that the skin material 6 covers the core material 7. The ratio of the skin material 6 and the core material 7 can be adjusted by adjusting the amount of the material, that is, the amount of the skin material 6 and the core material 7 injected by each of the injection machines 10 and 11.

  The molding die 12 is a mold. The molding die 12 is divided into a fixed die 12b and two movable dies 12c and 12d. The first movable die 12c moves in the direction of arrow A in FIG. 1, and the second movable die 12d moves in the direction of arrow B in FIG. The fixed mold 12b is provided with an injection port 12a and a sprue 12e, and the second movable mold 12d is provided with a gate 12f on the abutting surface with the fixed mold 12b. The gate 12f is provided at a position corresponding to the lower end of the spine 1 so that the processing traces obtained by removing the injection molded product (workpiece) from the molding die 12 and removing the resin at the gate 12f and sprue 12e portions are not conspicuous. Yes.

  As shown in FIG. 5, the step of filling the core material 7 and the skin material 6 into the molding die 12 includes a first injection step S21 in which only the skin material 6 is injected, and the skin material 6 after the first injection step S21. And a second injection step S22 for injecting the core material 7 and a third injection step S23 for injecting only the skin material 6 after the second injection step S22. In the first and second injection steps S21 and S22, the injected material reaches the product cavity 12g of the molding die 12, and in the third injection step S23, the injected material is sprue 12e or gate 12f of the molding die 12. The sprue 12e or gate 12f of the molding die 12 is shifted from the mixed portion of the core material 7 and the skin material 6 to the portion of the core material 7 alone. Note that the sprue 12e or gate 12f of the molding die 12 is a passage that guides material to the product cavity 12g, and is removed together with the product portion when the workpiece is released from the product portion. It means the part filled with the resin to be removed.

  Therefore, the filling of the material is a cycle of skin material 6 → skin material 6 and core material 7 → skin material 6. For example, the material (skin material 6) injected in the first injection step S21 is denoted by reference numeral P1 in FIG. The material (skin material 6 and core material 7) filled in the back side from the position shown and injected in the second injection step S22 is filled in the back side from the position shown by the symbol P2 in FIG. The material (skin material 6) injected in the injection step S23 is filled in front of the position P2. In the present embodiment, the position P1 is positioned near the center of the spine 1 in the height direction, and the position P2 is positioned in the middle of the sprue 12e. That is, the sprue 12e of the molding die 12 is shifted from the mixed portion of the core material 7 and the skin material 6 to the core material 7 only. A resin reservoir (not shown) may be provided in the middle of the sprue 12e, and the resin reservoir may be shifted from the mixed portion of the core material 7 and the skin material 6 to the core material 7 only.

  When the resin filled in the molding die 12 is hardened to some extent, the movable dies 12c and 12d are opened and the workpiece is taken out (work release). At this time, the resin hardened in the gate 12f and the sprue 12e is also removed from the mold 12 together as part of the work. Thereafter, the resin hardened in the gate 12f and the sprue 12e is removed from the workpiece.

  The spine 1 manufactured in this manner has an upper portion 1a, that is, a portion corresponding to the back side of the position P1 of the product cavity 12g is formed of the skin layer 4, and the lower portion 1b and the mounting portion 1c, that is, the position P1 of the product cavity 12g. The portion corresponding to the near side is made up of the core layer 3 and the skin layer 4. The ratio of the core layer 3 to the skin layer 4 is, for example, core layer 3: skin layer 4 = 7: 3. The ratio of the core layer 3 to the entire material may be uniform throughout the lower portion 1b and the attachment portion 1c, or may be changed continuously or stepwise in the material filling direction. Further, the ratio of the core layer 3 to the entire material including the upper portion 1a, that is, relative to the entire spine 1 may be changed continuously or stepwise.

  When the occupant of the chair 2 leans against the back 1, the back of the occupant mainly hits the upper part 1a of the back 1 and falls down, so that the load acts mainly on the upper part 1a and is bent mainly on the lower part 1b and the mounting part 1c. Stress is concentrated. The core layer 3 does not exist in the upper part 1a of the spine 1, and the ratio of the core layer 3 to the whole material is larger in the lower part 1b and the attachment part 1c than in the upper part 1a. For this reason, while being able to increase the intensity | strength of the lower part 1b and the attaching part 1c which are parts where a bending stress concentrates, the upper part 1a which is a part which a seated person touches can be made soft. That is, it is possible to secure both strength and flexibility as the back 1, which is a component of the chair 2, and to give the seated person a sense of security, stability and fit, and to improve the sitting comfort of the chair 2. Can do.

  In the present invention, the filling of the material is a cycle of skin material 6 → skin material 6 and core material 7 → skin material 6, and only the skin material 6 is injected at the beginning and end of one cycle. The next cycle can begin. For this reason, the productivity of the spine 1 can be improved. Even if only the skin material 6 is injected at the beginning and end of one cycle, only the core material 7 is detected from the position P2, that is, the mixed portion of the core material 7 and the skin material 6 (the material portion of the second injection step S22). Since the transition position to the portion (the material portion of the third injection step S23) is located at the sprue 12e or the gate 12f of the molding die 12, the core layer is formed on the lower portion 1b and the mounting portion 1c that require strength. 3, and when the workpiece is removed from the mold 12, the mixed portion of the core material 7 and the skin material 6 can be removed together from the mold 12. Only the skin material 6 can first be injected into the cavity 12g, and the upper portion 1a can be made an area of only the skin layer 4.

  In other words, in order to improve the productivity, simply filling the material with the cycle of skin material 6 → skin material 6 and core material 7 → skin material 6, for example, as shown in FIG. 6 reaches the product cavity 12g, and the part close to the gate 12f of the workpiece becomes an area of only the skin layer 4 where the core layer 3 does not exist. For this reason, the strength of the portion close to the gate 12f cannot be increased. Especially for the back 1 of the chair 2 and the like, it is necessary to make the position of the gate 12f correspond to the lower end of the lower portion 1b of the back 1 so that the gate removal processing trace is not conspicuous. It is difficult to make the core layer 3 exist in the part 1c and the periphery thereof. On the contrary, in order to make the core layer 3 exist in the attachment portion 1c and the periphery thereof, that is, the portion close to the gate 12f, if the last step of the material filling cycle is the injection process of the skin material 6 and the core material 7, for example, The core material 7 remains in a portion that is not removed together with the workpiece, such as the inside of the tip 13a, and the next material filling cycle starting from the skin material 6 cannot be started as it is.

  On the other hand, in the present invention, the filling of the material is a cycle of skin material 6 → skin material 6 and core material 7 → skin material 6, and position P2 is located at sprue 12e or gate 12f of molding die 12. Therefore, after completing one cycle of material filling, the next cycle can be started as it is, and there are a portion corresponding to the position of the gate 12f and a portion requiring a high strength. Even if it is the resin molded part 1 which corresponds, the intensity | strength of the part can be enlarged. In other words, productivity can be improved, and an area of only the skin layer 4 is formed on the innermost side of the product cavity 12g, and the skin layer 4 and the core layer 3 are mixed in a portion near the gate 12f of the product cavity 12g. Can be made.

  In the present invention, the resin molded part 1 is composed of the skin layer 4 and the core layer 3, the core layer 3 increases the strength, and the core layer 3 is covered with the skin layer 4 so that the appearance quality is inferior. Exposure of layer 3 is prevented. That is, it is possible to satisfy both the increase in strength as the resin molded part 1 and the appearance quality including good touch feeling. Here, the core material 7 of the core layer 3 is a synthetic resin material mixed with a reinforcing material, which further increases the component strength. That is, the present invention does not compensate for the insufficient strength of the core layer with the strength of the skin layer as in the conventional resin molded product, and the skin layer 4 alone has sufficient strength. Increases strength. For this reason, bending stress acts and it is suitable for the resin molded part 1 for chairs used over a long period of time. In particular, it is suitable for application to plate-like parts such as the back 1, a seat, and an armrest.

  In addition, when the intensity | strength of resin is made high, it is possible that impact resistance falls. That is, it can be considered that the impact resistance of the core layer 3 is lower than that of the skin layer 4. However, even when the impact resistance of the core layer 3 is lower than the impact resistance of the skin layer 4, the impact applied from the outside of the resin molded part 1 for the chair directly acts on the skin layer 4. Since it does not directly act on the core layer 3, the impact can be absorbed by the skin layer 4, and the impact resistance of the resin molded part 1 for a chair is excellent.

  Moreover, since it can be used as it is with the back 1 exposed, the manufacturing cost of the chair 2 can be reduced.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the above description, the resin molded part for a chair is the spine 1, but is not limited to the spine 1, and may be, for example, a seat or an armrest.

  In the above description, the resin molded part is for a chair. However, the resin molded part is not limited to a chair resin molded part, and may be other resin molded parts. For example, resin-molded parts such as various furniture other than chairs, car parts, household appliances, daily necessities, resin-molded parts for health appliances, and outer shell cases of various products that are often subject to impact may be used. In terms of good tactile sensation, it can be suitably applied to parts such as handrails and handles.

  In the above description, the manufacture of resin molded parts for chairs has been described. However, the manufacturing method of the present invention is not limited to the manufacture of resin molded parts for chairs, but is applied to the manufacture of resin molded parts other than for chairs. May be. For example, it can be applied to the manufacture of resin molded parts such as various furniture other than chairs, car parts, household appliances, daily necessities, resin molded parts for health equipment, and outer shell cases of various products that are subject to shock. good. In short, it can be suitably applied to resin molded parts that require strength and appearance or good tactile sensation, and there is no need to separately paint or the like in order to improve the appearance. For example, when a box-shaped part is to be formed and the gate must be positioned at the opening edge thereof, the manufacturing method of the present invention can be applied to maintain the appearance of the box-shaped part. In particular, the strength of the opening edge can be increased.

  In the above description, the sprue 12e of the molding die 12 is shifted from the mixed portion of the core material 7 and the skin material 6 to the portion of the core material 7 alone, but may be shifted at the gate 12f. In addition, a resin reservoir may be provided in the middle of the gate 12f, and the transition may be made in this resin reservoir.

  Moreover, in the above description, the resin molded part 1 for a chair used in an exposed state when assembled to a chair is taken as an example, but for example, a chair used in a state covered with a cover, a skin member, or the like. It may be applied to the resin molded part 1 for use.

  Furthermore, in the above description, the ratio of the core layer 3 is increased as the required strength of the resin molded part 1 for a chair is increased. However, the ratio of the core layer 3 is not changed partially as described above. May be uniform.

It is sectional drawing of the state which showed an example of embodiment of the resin molded part for chairs of this invention, and filled the material for shaping | molding. It is a side view of the chair using the resin molded part for chairs of this invention. It is a top view of the chair which uses the resin molded part for chairs of this invention. It is a conceptual diagram of the apparatus which manufactures the resin molded part for chairs of this invention. It is a figure which shows a material filling cycle. It is a figure for demonstrating the point which becomes a problem in general resin molding.

Explanation of symbols

1 Back (resin molded part for chair)
DESCRIPTION OF SYMBOLS 1a Back upper part 1b Back lower part 1c Back attachment part 2 Chair 3 Core layer 4 Skin layer 5 Chair main body 6 Skin material 7 Core material 12 Molding type 12e Molding type sprue 12f Molding type gate 12g Molding type Product cavity S21 First injection step S22 Second injection step S23 Third injection step

Claims (5)

  A core layer made of a synthetic resin material mixed with a reinforcing material and a skin layer made of a synthetic resin material not mixed with a reinforcing material, and the periphery of the core layer is covered with the skin layer Resin molded parts for chairs.   The resin molded part for a chair according to claim 1, wherein a portion having a higher required strength has a higher proportion of the core layer.   The resin molded part for a chair according to claim 1 or 2, wherein the resin molded part is exposed in a state assembled to a chair.   2. The resin molded part for a chair according to claim 1, wherein the resin layer is used as a back of the chair, and the ratio of the core layer is higher in the lower part and the attachment part to the chair body than in the upper part. Resin molding in which the core material made of a synthetic resin mixed with a reinforcing material is covered with the skin material made of a synthetic resin not mixed with the reinforcing material in the product cavity of the molding die. In the method for manufacturing a component, the step of filling the molding material with the core material and the skin material includes a first injection step of injecting only the skin material, and the skin material and the skin after the first injection step. A second injection step of injecting a core material; and a third injection step of injecting only the skin material after the second injection step, and molding the material injected in the first and second injection steps Reaching the product cavity of the mold, the material injected in the third injection step reaches the sprue or gate of the mold, and the core material and the skid at the sprue or gate of the mold. Method for producing a resin molded part, wherein the shifting from mixed portion of wood to parts of only the core material.