JP4077491B2 - Resin lid - Google Patents

Description

  The present invention relates to a resin lid, and more particularly to a resin lid with improved impact resistance.

  Conventionally, a synthetic resin, such as a resin lid made of polyvinyl chloride, has been used as a lid that covers the upper opening of the riser pipe such as a manhole, but depending on its size and wall thickness, impact resistance is not sufficient. In some cases, the vehicle may be damaged by a vehicle impact or a falling object. Although the resin material which improved the impact resistance by adding the modifier to the whole resin lid can also be used for the whole lid, the cost will be greatly increased. For this reason, a metal lid is used instead of a resin lid for applications in which impact resistance is important.

  On the other hand, when injection molding of housing materials such as household electrical appliances made of resin raw materials and pipe fittings, unnecessary parts such as gates and scrap are generated, or when plastic resin pipes are continuously extruded, molding A large amount of scrap may be generated in the initial stage until the conditions stabilize. In addition, when a synthetic resin pipe that has deteriorated due to the end of its useful life is renewed, a large amount of used waste material may be generated. In recent years, disposal of such resin scrap and used waste has become a major problem.

Conventionally, resin scraps and used waste materials have been disposed of by incineration or landfill. However, when resin scraps are incinerated, there is a problem that dioxins are generated and the environment is polluted. Yes. In addition, when resin scraps and waste materials are buried in the ground, the place where they are buried becomes a problem, as well as the synthetic resin is not decomposed and corroded over a long period of time. Has reached. Therefore, it has been proposed to grind resin scraps and used waste materials and use them as recycled raw materials (see, for example, Patent Document 1), but the response is not sufficient. there were.
JP 2001-41362 A

  Accordingly, an object of the present invention is to provide a resin lid using a resin molded product having a three-layer structure in which the impact resistance of the resin lid is effectively improved.

In order to achieve the above object, the resin lid of the present invention comprises a resin molded product formed in a three-layer structure having an intermediate layer and inner and outer layers covering the inner and outer surfaces of the intermediate layer by injection molding . in the resin-made cover which is installed so as to cover the upper opening, the intermediate layer, formed of polyvinyl chloride containing modifier for improving the impact resistance, the inner and outer layers, containing the modifying agent It is characterized by being formed from unused polyvinyl chloride , and the mixing ratio of the polyvinyl chloride modifier forming the intermediate layer is 100 parts by weight of unused polyvinyl chloride containing no modifier. It is characterized by being 8 to 15 parts by weight.

According to the resin lid of the present invention, the impact resistance of the resin lid is improved by using polyvinyl chloride containing a modifier in the intermediate layer of the three-layer structure. The required impact resistance can be obtained at a lower cost compared to the case where a modifier is added.

  FIG. 1 is a cross-sectional view of a resin lid showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a manhole showing a use state of the resin lid. As shown in FIG. 2, the resin lid 10 is mounted via a lid receiving frame 31 so as to cover the upper opening of the rising pipe 30 provided on the upper part of the drainage tub 20 to which the drain pipes 21 and 22 are connected. It is what is done.

  The resin lid 10 has a disc-shaped lid body 11 and a slot 12 provided in a ring shape on the inner peripheral surface of the back surface of the lid body 11. It has been subjected. The resin lid 10 is attached so that packing is attached to the outer periphery of the opening portion 12 and inserted into the small diameter portion of the lid receiving frame 31, and the lid main body 11 is fitted into the large diameter portion of the lid receiving frame 31. .

The resin lid 10 is a resin molded product having a three-layer structure having an intermediate layer A, an inner layer B and an outer layer C covering the inner and outer surfaces of the intermediate layer A, and the intermediate layer A has an impact resistance. using polyvinyl chloride containing modifier to improve, said inner layer B and the outer layer C is manufactured by injection molding using a polyvinyl chloride unused containing no recycled materials.

  In addition, in the manhole shown in FIG. 1, the intermediate | middle layer using the resin raw material containing the recycled raw material obtained by grind | pulverizing the resin scrap and waste material as the drainage basin 20, the riser pipe 30, and the lid receiving frame 31, and the recycled raw material Three-layered resin molded products comprising the inner layer and the outer layer using unused resin raw materials not contained are used.

Said as a modifier used for the intermediate layer A, rubber-based materials, can be used, for example MBS resin, as other additives, tin stabilizers, heat stabilizers, lubricants, processing aids, Various additives such as pigments, plasticizers, fillers, antistatic agents, ultraviolet absorbers, flame retardants and the like can be added.

  As a suitable blending example, 8 to 15 parts by weight of a modifier, 0.5 to 3 parts by weight of a stabilizer, 0.1 to 1.0 part by weight of a lubricant, and a processing aid 0 with respect to 100 parts by weight of polyvinyl chloride. 0.1 to 1.0 part by weight and 0.1 to 1.0 part by weight of pigment.

Further, recycled materials obtained by crushing the resin scrap and waste material, polyvinyl chloride le or Ranaru resin molded article, For example, building materials of waste, such as casing and pipe fittings of household electrical products, during injection molding It was obtained by crushing unnecessary members such as gates and scrap generated in the above. As the main component of the resin raw material constituting the intermediate layer A of the drainage basin 20, the riser pipe 30 and the lid receiving frame 31, it is possible to use only the recycled raw material or a mixture of this recycled raw material and an unused resin raw material. can, also, as the resin material constituting the inner layer B and the outer layer C, and a resin material with the intermediate layer a compatible, polyvinyl chloride Le containing no recycled material can be used.

  As described above, various resin raw materials can be used as the intermediate layer A of the drainage basin 20, the rising pipe 30 and the lid receiving frame 31, the inner layer B and the outer layer C covering the inner and outer surfaces of the intermediate layer A, and are made of vinyl chloride resin. Considering the current situation in which a large amount of used waste material and scrap is generated and the fact that pipes made of hard vinyl chloride resin are frequently used as the drain pipes 21 and 22 connected to the drainage basin 20, the intermediate layer A A recycled raw material made of hard vinyl chloride resin can be suitably used, and an unused hard vinyl chloride resin containing no recycled raw material can be suitably used for the inner layer B and the outer layer C covering the inner and outer surfaces of the intermediate layer A.

  The riser tube 30 can be manufactured by applying a conventional three-layer tube extrusion molding technique, but the lid 10, the drainage basin 20, and the lid receiving frame 31 are injection molding machines having two resin flow paths. Can be manufactured using. The injection molding of the lid 10 is a process for injecting an unused resin raw material containing no recycled raw material into a gate of a mold having a molding cavity corresponding to the outer shape of the lid 10 as indicated by an imaginary line in FIG. A nozzle 40 of an injection molding machine provided with one resin flow path 41 and a second resin flow path 42 for injecting the resin raw material containing the modifier is brought into contact with the two raw resin from the nozzle 40. This is done by injecting a predetermined amount into the molding cavity in a predetermined order. Although the position of the gate is arbitrary, the gate mark (gate opening) can be made inconspicuous by positioning the gate at the lower end of the differential opening 12 provided in the lower part of the lid 10.

  In the injection molding operation, after a mold is clamped to form a molding cavity, first, a predetermined amount of an unused resin material that does not contain a recycled material is injected from the first resin channel 41. Next, the resin raw material containing the modifier and the regenerated raw material is injected from the second resin flow path 42 into the molding cavity, and the inside of the cavity is almost filled with the resin raw material.

  At this time, the resin raw material containing the modifier injected later into the unused resin raw material that does not contain the recycled raw material previously injected into the molding cavity, and both resin raw materials reach the end of the cavity. Go around evenly. That is, the inner layer B and the outer layer C are uniformly distributed to the end of the cavity in a state where the surface of the resin raw material containing the modifier and the regeneration raw material to be the intermediate layer A is covered with the skin layers (the inner layer B and the outer layer C). The intermediate layer A does not protrude from the surface. In addition, the ratio of the resin raw material which does not contain the reproduction | regeneration raw material which injects first, and the resin raw material which contains the modifier inject | emitted after that is the thickness of the intermediate | middle layer A, the inner layer B, and the outer layer C, the resin raw material It can be set as appropriate in consideration of the type of the above.

  Finally, a small amount of unused resin material that does not contain a regenerated material is injected from the first resin channel 41 into the molding cavity. As a result, the gate opening corresponding to the gate can be covered with the resin raw material not containing the regenerated raw material, and the staying resin at the tip of the nozzle 40 is not containing the modifier or the regenerating raw material for the next shot. The resin raw material used can be substituted. When the mold is opened through the above molding steps, the lid 10 having a good appearance can be obtained as shown in FIG.

It is sectional drawing of the resin-made lid | covers which show one example of this invention. It is sectional drawing of the manhole which shows the use condition of resin-made lids.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Resin lid | cover, 11 ... Lid main body, 12 ... Mouth part, 20 ... Drainage tank, 21, 22 ... Drain pipe, 30 ... Rising pipe, 31 ... Lid receiving frame, 40 ... Nozzle, 41 ... First resin flow Path 42 second resin flow path A intermediate layer B inner layer C outer layer

Claims (2)

In a resin lid formed by a resin molded product formed in a three-layer structure having an intermediate layer and an inner layer and an outer layer covering the inner and outer surfaces of the intermediate layer by injection molding, the resin lid installed so as to cover the upper opening of the riser pipe , The intermediate layer is formed of polyvinyl chloride containing a modifier for improving impact resistance, and the inner layer and the outer layer are formed of unused polyvinyl chloride containing no modifier. Resin lid. The mixing ratio of the modifier in the polyvinyl chloride forming the intermediate layer is 8 to 15 parts by weight with respect to 100 parts by weight of unused polyvinyl chloride not containing the modifier. Item 2. A resin lid according to Item 1.

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