JP5705532B2 - Resin lid for use in any of trough, cable duct, and pit for storing cable, and method for manufacturing the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a resin lid for a trough or the like that accommodates a cable or the like inside and is disposed beside a track.

  Conventionally, a trough made of concrete or resin is used on the side of the track, and various cables are stored in the trough and installed over a long distance. The trough is usually covered with a lid to prevent rainwater, earth and sand from entering the trough.

  In recent years, a trough and a lid for a trough are made of resin in consideration of laying workability and the like. In particular, recycled plastics are used in consideration of recent environmental problems and costs.

  As a lid for such a trough made of resin, there is a pit lid made of synthetic resin that is placed on the step portions on both edges of the upper opening of the pit (Patent Document 1).

Utility Model Registration No. 3007971

  By the way, such a trough lid is laid on the side of the track over a long distance, but the appearance of the laid lid is not always good. For example, when recycled plastic is used, the resin may expose a plurality of colors such as black or gray, and it is difficult to color the resin with any color or to print a photograph or text on the surface. However, if the paint is applied after molding, the paint or the like is difficult to get on the olefin resin, so that the paint may be peeled off. In addition, when recycled plastic is used, fine cracks and surface roughness may occur on the surface during molding. However, it is disadvantageous in cost to form the entire lid with a special colored resin or the like.

  On the other hand, there is a method in which the product molded on the primary side is left in the same mold core, put into the cavity on the secondary side, the secondary side material is poured, and the different materials are molded integrally. In this method, since two molds are required and two injection devices are required, the cost of equipment and the like becomes a problem.

  In addition, there is a method of obtaining a two-layered resin molded body by heating a film on the surface layer and inserting a film formed by a vacuum press or the like into an injection mold and performing injection molding. However, in this case, the film must be formed into a surface shape in advance, and the productivity is not always good.

  On the other hand, an operator or the like may walk on such a trough lid. At this time, since the trough lid is made of resin, in order to prevent the operator from slipping on the lid, unevenness for preventing slip is usually formed on the trough lid.

  On the other hand, in order to improve the appearance of the lid, if the lid is to be coated with a resin, the coating resin does not follow the unevenness at the time of manufacture, and wrinkles and the like are formed in the vicinity of the convex portion of the lid. However, when the coating resin is made thicker, there arises a problem of peeling of the coating and cost.

The present invention has been made in view of such problems, and has a simple structure, excellent appearance even when recycled plastic (recycled resin) is used, and generation of wrinkles even when unevenness is formed on the surface. An object of the present invention is to provide a resin lid for use in any of troughs, cable ducts, and pits for storing inexpensive cables .

In order to achieve the above-described object, the first invention is a resin lid having a multilayer structure having a resin main body layer and a coating layer formed on the surface of the main body layer. In addition, the coating layer is a resin foam, an uneven shape is formed on the cover layer on the surface of the lid, the uneven height of the uneven shape is 20 mm or less, and the thickness of the resin foam is 0.5 to It is 5 mm, and the expansion ratio of the resin foam is 1.5 to 5 times, and is a resin lid used for any of troughs, cable ducts, and pits for storing cables .
2nd invention is a resin-made cover body, Comprising: It is a multilayer structure which has a resin-made main body layer and the coating layer formed in the surface of the said main body layer, The said coating layer is a resin foam. The cover layer on the surface of the lid has an uneven shape, and the main body layer has an uneven shape corresponding to the uneven shape formed on the cover layer at the interface with the cover layer, The height of the irregularities of the shape is 20 mm or less, the thickness of the resin foam is 0.5 to 5 mm, and the expansion ratio of the resin foam is 1.5 to 5 times. Resin lid used for troughs, cable ducts, and pits.

  The coating layer includes at least one of an ultraviolet absorber for improving weather resistance, an inorganic powder for improving wear resistance, glass fiber, an antistatic agent, a flame retardant, and a heat insulating / heat shielding agent. It may contain.

  The main body layer is preferably a recycled resin containing polyethylene or polypropylene. It is desirable that the resin constituting the main body layer and the resin constituting the covering layer have compatibility, and the main body layer and the covering layer are integrated by fusion.

According to the first and second inventions, since the resin lid has a multi-layer structure, and the coating layer as the surface layer is a foamed resin, an uneven shape is formed on the top surface of the lid without making the coating layer thicker than necessary. In this case, there is no occurrence of wrinkles or the like. That is, if a foam material is used when forming the coating layer, it can be compressed not only in the elongation of the material but also in the thickness direction, so that the surface uneven shape can be more reliably followed.

  Further, the two layers can be reliably fused by partially melting the joint surface of the coating layer by utilizing the heat of the melted resin of the main body layer. On the other hand, if the coating layer is molded with a non-foamed material, the heat of the molten resin of the main body layer easily escapes to the mold through the coating layer, so the temperature of the joint surface with the coating layer is unlikely to rise, Sexuality gets worse. That is, by using a foam, since there is a heat insulating effect of the coating layer, it is difficult for heat to escape to the mold, the temperature of the bonding surface between the main body layer and the coating layer is increased, and the coating layer is easily melted.

  In particular, if the main body layer is made of a recycled resin containing polyethylene or polypropylene, the cost is low, and the resin can be reused, so the burden on the environment is small.

  Moreover, if the resin which comprises a coating layer is made to contain the ultraviolet absorber which improves a weather resistance, degradation, such as a crack by an ultraviolet-ray, can be prevented. In addition, the resin constituting the coating layer contains inorganic powder or glass fiber that improves wear resistance, thereby improving the strength when the worker walks on the lid and preventing wear. it can.

3rd invention is a manufacturing method of the resin lid which has concavo-convex shape on the surface of a foam, the concavo-convex height of the concavo-convex shape is 20 mm or less, and thickness is 0.5-5 mm, A sheet-like or board-like foam with a foaming ratio of the resin foam of 1.5 to 5 times is placed in a mold having an uneven shape on one side, and a molten resin is placed on the foam Then, the trough for storing the cable , wherein pressing is performed by the mold, the foam and the molten resin are fused to form an uneven shape on the foam side, and the shape is a lid . This is a method for manufacturing a resin lid used for either a cable duct or a pit .

According to the third aspect of the invention, it is possible to form a resin lid body that is simple and low cost and excellent in appearance, and the main body layer and the coating layer can be reliably fused.

  According to the present invention, an inexpensive resin lid having a simple structure and excellent in appearance even when using recycled plastic (recycled resin) or the like is formed, and there is no generation of wrinkles even when unevenness is formed on the surface. Can be provided.

The perspective view which shows the lid | cover 1 for troughs. It is sectional drawing of the lid | cover 1 for troughs, (a) is the sectional view on the AA line of FIG. 1, (b) is the B section enlarged view of (a). The figure which shows the manufacturing process of the lid | cover 1 for troughs. The figure which shows the manufacturing process of the lid | cover 1 for troughs. The figure which shows the other manufacturing process of the lid | cover 1 for troughs.

  Hereinafter, the trough lid 1 according to the embodiment of the present invention will be described. 1 is a perspective view showing a trough lid 1, FIG. 2 is a cross-sectional view of the trough lid 1, FIG. 2A is a cross-sectional view taken along the line AA in FIG. 1, and FIG. It is the B section enlarged view of (a). In the following description, a trough lid will be described, but the resin lid of the present invention can also be applied to lids for cable ducts, drainage grooves, pits, and the like.

  The trough lid 1 has a substantially rectangular shape in plan view. The trough lid 1 has a multi-layer structure mainly composed of a main body layer 3 constituting the trough lid 1 and a covering layer 5 covering the upper surface of the trough lid 1. In addition, another layer such as an adhesive layer may be further formed between the main body layer 3 and the covering layer 5.

  Further, the shape of the trough lid of the present invention is not limited to the illustrated example, and the length, width, thickness, surface form, and the like are appropriately set, and a bent shape, an L shape, or the like is used depending on the part to be used. The outer shape is set as appropriate. For example, in accordance with the corresponding trough shape, a step may be provided on the side of the trough lid, or a rib or the like may be formed on the bottom surface side. The upper surface of the trough lid 1 may be flat (except for the convex portion 7), or the trough lid 1 may be bent or bent slightly upward so that the side of the trough lid 1 is laid down. You may form so that an edge part may become low. Moreover, you may form the handle (notch) used at the time of handling in the side part of the lid | cover for troughs.

  The body layer 3 is made of resin, and the material is not specified as long as it has a certain degree of strength and durability. However, considering the workability such as cost and weight reduction, recycled plastic (for example, general recovered by container packaging recycling method) A resin composition made of waste plastic (70% by mass of polyethylene, 20% by mass of polypropylene, 10% by mass of polystyrene) or the like can be used.

  The coating layer 5 is a resin foam, and for example, a foam such as polypropylene, polyethylene, EVA, and PET can be used. As a foam, it is desirable that the expansion ratio is 1.5 to 5 times. When the expansion ratio is 1.5 times or less, it is impossible to follow the unevenness on the upper surface of the trough lid 1 during molding, which will be described later, and wrinkles may occur. Further, when the expansion ratio is 5 times or more, the strength and the like are lowered. Furthermore, since the resin foam absorbs the press pressure at the time of molding and the contact surface pressure with the main body layer is lowered to deteriorate the adhesion, there is a risk of peeling. Furthermore, the bubble diameter is desirably 500 μm or less. When the bubble diameter is larger than 500 μm, the resin portion and the bubble portion are larger and the foam coating layer is not easily crushed at the time of pressing, the surface pressure becomes non-uniform, and the adhesion tends to vary.

  In addition, it is desirable that the resin constituting the coating layer 5 and the resin constituting the main body layer 3 have compatibility. Further, the melting point of the resin constituting the coating layer 5 may be higher than the melting point of the resin constituting the main body layer 3.

  An uneven shape is formed on the surface of the trough lid 1 for the purpose of preventing slipping. This unevenness also functions as a rib and contributes to improving the strength of the trough lid. In addition, although the figure shows the example in which only the convex part 7 was formed, it may replace with the convex part 7 or in addition to the convex part 7, you may form a recessed part. In the following description, an example in which the convex portion 7 is formed will be described. Moreover, the pattern (unevenness | corrugation shape, arrangement | positioning, etc.) of the convex part 7 is not restricted to the illustrated example.

  As shown in FIG. 2, in the convex part 7, the main body layer 3 and the coating layer 5 are formed in a convex shape. Here, the thickness of the main body layer 5 is appropriately set according to the design thickness of the trough lid 1. The thickness of the coating layer 5 is set according to the height of the convex portion 7 or the like. Note that the cross-sectional shape of the convex portion 7 does not have to be an arc shape as shown in the figure, and may be a rectangular shape such as a trapezoidal shape having a flat portion on the surface, or a wave in which irregularities are repeatedly arranged on the entire surface. It is good as a type.

  When the height of the convex portion 7 (height C in FIG. 2B) increases, the thickness of the coating layer 5 (thickness D in FIG. 2B) is set to the height of the convex portion 7 (in the case of the concave portion). Needs to have a thickness corresponding to the depth). That is, when the height of the convex portion 7 is increased, it becomes difficult for the coating layer 5 to follow the convex shape when the trough lid 1 is molded, and the generation of wrinkles or the like cannot be suppressed. Therefore, the thickness of the coating layer 5 is set according to the uneven height.

  For example, the height of the convex portion 7 is desirably 20 mm or less. This is because if the thickness is 20 mm or more, the coating layer may be wrinkled even if it is a foam. At this time, the covering layer 5 (the thickness of the foam described later) is preferably 0.5 to 5 mm. If the thickness of the coating layer is too thin, the shape of the projection cannot be followed and wrinkles may occur, and if it is too thick, the resin foam absorbs the pressing pressure during molding and the contact surface with the main body layer This is because the pressure is lowered and the adhesiveness is lowered, so that there is a risk of peeling at the interface between the main body layer and the coating layer.

  Next, a method for manufacturing the trough lid 1 will be described. 3 to 4 are schematic views showing the manufacturing process of the trough lid 1. First, as shown in FIG. 3 (a), a foam 9 manufactured in advance is placed in a lower mold 11a in which a concave portion 13 having a shape corresponding to the convex portion 7 formed on the surface is formed. (The direction of arrow E in the figure). FIG.3 (b) is a figure which shows the state in which the foam 9 was installed in the metal mold | die 11a.

  The foam 9 is a sheet-like or board-like foam having a plurality of pores inside as described above. As the foam 9, for example, “F-cell” (registered trademark) manufactured by Furukawa Electric Co., Ltd. can be used.

  Next, as shown in FIG. 4A, a molten resin 15 (having viscosity) is disposed on the foam 9. The molten resin 15 is configured in an amount corresponding to the shape of the lid manufactured in advance. From this state, the upper mold 11b is pressed against the molten resin 15 (in the direction of arrow F in the figure).

  FIG. 4B is a diagram showing a state where the press is completed by the mold 11b. The molten resin 15 is molded into the shape of the trough lid 1 by the molds 11a and 11b. At this time, the foam 9 is pressed against the mold 11 a side by the molten resin 15, and the concave portion 13 is deformed along the shape of the concave portion 13 to form the convex portion 7.

  The molten resin 15 constitutes the main body layer 3, and the foam 9 constitutes the coating layer 5. At the interface between the molten resin 15 and the foam 9, the foam 9 is partially softened by the heat and press pressure of the molten resin 15, and the molten resin 15 and the foam 9 are fused and integrated. At this time, if the resins constituting each other have compatibility, they can be integrated more reliably.

  In addition, since the foam 9 has many pores inside and has poor heat conduction, the temperature near the interface between the foam 9 and the molten resin is reliably increased by the heat from the molten resin 15. Therefore, heat does not escape to the mold, the interface can be reliably fused, and the entire foam can be prevented from melting. Therefore, it is possible to prevent the molten resin 15 from exuding below the foam 9 (on the mold 11a side).

  After completion of molding, cooling is performed for a predetermined time, the mold is opened, and the trough lid 1 molded with a take-out pin or the like (not shown) is removed from the mold 11a, whereby the molding of the trough lid 1 is completed.

  If the foam 9 contains a pigment or the like in advance, the trough lid 1 having a desired color can be formed. Moreover, the trough lid | cover 1 which has a desired pattern, a photograph, a character, and a color can be obtained by giving a printing process to the surface of the foam 9 previously. In addition, by applying a pigment only to the concave part of the mold for press molding, only the convex part of the molded product can be colored, so only the convex part of the molded product is colored, and characters and figures are drawn on the lid. Can do. If it does in this way, the logo mark of the company which uses a resin-like cover body can also be raised and used, and the kind and use of the cable in a trough can be described on a cover body.

  In the present invention, the main layer 3 (molten resin 15) and the coating layer 5 (foam 9) are usually added with an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, a heat insulation / heat shield. You may mix | blend suitably additives, such as ceramic beads which have an effect, in the range which does not impair the characteristic of this invention. In particular, by applying the additive only to the coating layer 5, the characteristics can be maintained without being added to the main body layer 3, and the cost can be reduced.

  For example, if the foam 9 contains an ultraviolet absorber, the weather resistance of the surface of the molded trough lid can be improved, and deterioration due to sunlight or the like can be prevented. In addition, by adding an inorganic material such as glass fiber or inorganic powder that improves mechanical properties to the foam 9 in advance, the wear resistance of the surface of the molded trough lid, the strength of the trough lid, etc. Can be improved. Further, if an antistatic agent is contained, it is possible to prevent the influence of static electricity that the operator receives while passing on the lid. Furthermore, for example, if a predetermined amount of a flame retardant such as aluminum hydroxide or magnesium hydroxide is contained, it is possible to prevent the spread of fire from the outside.

  According to the present invention, a trough lid having an excellent appearance can be obtained. In particular, even if recycled plastic is used as the material for the trough lid, a coating layer is formed, so that a trough lid with a desired appearance that has no surface roughness, low cost and high environmental adaptability is provided. Can be obtained.

  In addition, since the material constituting the coating layer 5 is the foam 9, even when an uneven shape such as a slip stopper is formed on the surface of the trough lid 1, the foam 9 itself is formed when the trough lid 1 is formed. However, it is possible to follow a slight thickness change and shape change, so that the generation of wrinkles in the vicinity of the uneven shape can be prevented. Further, it is possible to prevent cracking of the coating layer at the time of molding of the trough lid, and leakage of the internal molten resin to the outside.

  Further, it is possible to easily add functions such as weather resistance and wear resistance to the coating layer 9, and even in this case, it is not necessary to add the additive to the main body layer 3. . For this reason, it is only necessary to add the additive to the coating layer 9 and only the minimum necessary additive can be used, so that the weather resistance and the wear resistance can be improved efficiently.

  The method for manufacturing the trough lid 1 is not limited to the above-described example. For example, FIG. 5 is a schematic diagram showing another manufacturing process. First, the main body layer 3 having a predetermined shape is formed by a known method. The main body layer 3 may be manufactured by press molding, for example. At this time, the portion corresponding to the convex portion 7 formed on the surface of the completed trough lid 1 has a shape corresponding to the shape of the convex portion 7 in advance (in consideration of the thickness of the covering layer rather than the convex portion 7). A slightly small convex portion 7a is formed.

  Next, as shown to Fig.5 (a), the shape | molded main body layer 3 is arrange | positioned on the metal mold | die 11c. A foam 9 is disposed on the main body layer 3. In this case, for example, the melting point of the foam 9 may be set higher than the melting point of the main body layer 3, and the foam may be disposed on the main body layer 3 in a state where the foam 9 is softened.

  In this state, the mold 11d is lowered to press the foam 9 against the main body layer 3 (in the direction of arrow G in the figure). FIG. 5B is a diagram showing a state in which the main body layer 3 and the clothing layer 5 are formed by the molds 11c and 11d. In the mold 11d, a concave portion 13a having a shape corresponding to the formed convex portion 7 is formed at a portion corresponding to the convex portion 7a.

  By pressing with the molds 11c and 11d, the convex part 7 is formed on the foam 9 by the concave part 13a of the mold 11d. That is, the convex part 7 is formed on the convex part 7a. At this time, the foam 9 is deformed into the shape of the convex portion 7, but since the foam 9 has pores inside, it can easily follow the deformation of the thickness. Therefore, there is no occurrence of wrinkles in the vicinity of the convex portion 7.

  After completion of the molding, cooling is performed for a predetermined time, and the trough lid 1 molded with a take-out pin or the like (not shown) is extracted from the molds 11c and 11d, and the molding of the trough lid 1 is completed.

  Note that an adhesive may be applied in advance to at least one of the upper surface of the main body layer 3 or the rear surface of the foam body 9 to bond the foam body 9 and the main body layer 3 together. Further, a sheet or the like as an adhesive may be disposed between the main body layer 3 and the foam 9. For example, a hot melt type adhesive sheet may be arranged, and an adhesive layer may be formed between the coating layer 5 and the main body layer 3 by heat during pressing to integrate the two.

  The covering layer 5 may be formed of a plurality of layers (a plurality of foams). Moreover, the coating layer 5 does not necessarily need to be formed on the entire upper surface of the main body layer, or the coating layer 5 may be formed on the side surface of the main body layer 3 as necessary.

  As described above, the trough lid of the present invention can be obtained by any manufacturing method. In addition to the press molding described above, the manufacturing method can be appropriately selected according to the type and size of the resin lid to be molded, such as injection molding, compression molding, and extrusion molding.

  At this time, the main body layer 3 is made of recycled plastic, and the clothing layer 5 is made of foam, so that the appearance is low because there is no generation of surface wrinkles during production, and coloring, patterns, printing, etc. are possible. In addition to being easy to impart functions such as weather resistance and wear resistance, the amount of additive used is also the minimum required (amount corresponding to the surface coating layer 5), so the cost is low. This is also advantageous.

  Hereinafter, the aspect and appearance of the resin lid were evaluated. As the lid, one having a length of 500 mm × width of 200 mm × thickness of 15 mm was used. On the surface, protrusions having respective heights were formed. As the main body layer, a recycled resin of 70% by mass of polyethylene, 20% by mass of polypropylene, and 10% by mass of polystyrene was used.

  Each molded product was molded by the manufacturing method shown in FIGS. The molten resin was extruded by a twin screw extruder at a resin temperature of 230 ° C. and placed in a mold.

  About each molded article after shaping | molding, it was confirmed visually whether the wrinkles generate | occur | produced in the convex part vicinity of the surface. Moreover, it was confirmed visually that there was no peeling of the coating layer. Table 1 shows the conditions and evaluation results of each molded product.

  The “convex height” in the table is the height of the convex portion on the surface of the molded product. The expansion ratio and thickness are the expansion ratio and thickness of the foam constituting the coating layer, and “non-foaming” is a resin sheet that is not a foam. For “wrinkles” and “peeling”, “x” indicates that the surface of the coating layer is wrinkled, and peeling is observed on the coating layer. did.

  As is apparent from the table, the product No. 1-No. No wrinkles or peeling was seen in 5. On the other hand, no. Since the coating layer 6 was not a foam, wrinkles were observed. No. In No. 7, since the coating layer was not a foam and the coating layer was thick, wrinkles and peeling were confirmed. That is, it can be seen that it is difficult to follow the convex portions on the surface of the molded product only by the thickness of the coating layer.

  No. In No. 8, wrinkles were confirmed even when a foam was used for the coating layer because the height of the convex portion exceeded 25 mm and 20 mm. No. In No. 9, since the coating layer was too thin, it could not follow the convex portion and wrinkles occurred. No. No. 10 caused peeling because the expansion ratio was too high. No. No. 11 was peeled off because the coating layer was too thick.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs.

DESCRIPTION OF SYMBOLS 1 ......... Trough cover 3 ......... Main body layer 5 ......... Coating layers 7, 7a ......... Protrusion 9 ...... Foam bodies 11a, 11b, 11c, 11d ......... Molds 13, 13a ... ... Recess 15 ......... Molded resin

Claims (6)

A resin lid,
A resin body layer;
A multilayer structure having a coating layer formed on the surface of the main body layer,
The coating layer is a resin foam,
An uneven shape is formed on the cover layer on the surface of the lid,
The uneven height of the uneven shape is 20 mm or less, the thickness of the resin foam is 0.5 to 5 mm, and the expansion ratio of the resin foam is 1.5 to 5 times. Resin lid used for any of troughs, cable ducts, and pits that store cables . A resin lid,
A resin body layer;
A multilayer structure having a coating layer formed on the surface of the main body layer,
The coating layer is a resin foam,
An uneven shape is formed on the cover layer on the surface of the lid,
In the main body layer, an uneven shape corresponding to the uneven shape formed in the covering layer is formed at the interface with the covering layer ,
The uneven height of the uneven shape is 20 mm or less, the thickness of the resin foam is 0.5 to 5 mm, and the expansion ratio of the resin foam is 1.5 to 5 times. Resin lid used for any of troughs, cable ducts, and pits that store cables . The resin body used for any of the trough, cable duct, and pit for housing the cable according to claim 1, wherein the main body layer is a recycled resin containing polyethylene or polypropylene. . The resin constituting the main body layer and the resin constituting the covering layer have compatibility, and the main body layer and the covering layer are integrated by fusion. A resin lid used for any of the trough, cable duct, and pit for storing the cable according to any one of Items 3 to 4. The coating layer has at least one of an ultraviolet absorber for improving weather resistance, or an inorganic powder, glass fiber for improving wear resistance, and further an antioxidant, an antistatic agent, a flame retardant, and a heat insulating / heat shielding agent. 5. A resin lid used for any of troughs, cable ducts, and pits for storing cables according to any one of claims 1 to 4, characterized in that any one of them is contained. A method for producing a resin lid having an uneven shape on the surface of a foam ,
The uneven height of the uneven shape is 20 mm or less,
A sheet-like or board-like foam having a thickness of 0.5 to 5 mm and a foaming ratio of the resin foam of 1.5 to 5 times is placed in a mold having an uneven shape on one surface,
A molten resin is placed on the foam and pressed by the mold, and the foam and the molten resin are fused to form an uneven shape on the foam side, and a lid shape is formed. A method of manufacturing a resin lid used for any of troughs, cable ducts, and pits for storing cables characterized by the above.

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