Method for manufacturing grid-shaped plastic plywood using waste plastic and the plastic plywood

Abstract

The present invention relates to a method for manufacturing a grid-type plastic plywood using waste plastic and the plastic plywood said, comprising the steps of: selecting usable waste plastic among PET, PP, and HDPE; selecting only PET from the selected waste plastic, or selecting waste plastic composed of a mixture of PP and HDPE and two or three types; melting at 250°C, which is higher than the melting temperature of PET, to form a grid-type plastic bottom plate (110) and a cover plate (130) of a predetermined size (S110); applying an adhesive layer to the upper surface of the bottom plate protrusion (111) of the bottom plate (110) formed in the molding step (S110), and then attaching the cover plate (130) to form a grid-type plastic plywood (S120); and applying an adhesive layer (131) to the upper surface of the cover plate (130), and then attaching a surface plate (150) to the adhesive layer (131) (S130). Including the above, in the manufacture of plywood, waste plastic is utilized to injection mold the bottom plate and the cover plate, respectively, and bond them together with a protruding adhesive layer to easily produce a grid-type recycled plastic plywood, thereby simplifying the production process and reducing the production cost when manufacturing grid-type recycled plastic plywood.

Description

Technology Field

[0001] The present invention relates to a method for manufacturing a grid-type plastic plywood using waste plastic and the plastic plywood said. More specifically, the invention relates to a method for manufacturing a grid-type plastic plywood using waste plastic and the plastic plywood said, wherein the bottom plate and the cover plate of the plastic plywood are formed using waste plastic, the bottom plate and the cover plate are bonded together, and then the surface plate is bonded together, thereby comprising a bottom plate made of waste plastic and a surface plate made of wood. Background Technology

[0002] Generally, plywood is manufactured by cutting large-diameter timber, such as tropical hardwoods like Nawang (Philippine mahogany), to make veneers, and then bonding multiple veneers together.

[0003] However, as the large-diameter tropical hardwoods used as raw materials gradually became depleted and the price of large-diameter tropical hardwoods became very high, and as plywood was manufactured by bonding several sheets of expensive wood veneer, there was a combination of complex and costly manufacturing processes.

[0004] Therefore, the aim is to provide a groundbreaking technology that utilizes inexpensive waste plastic as a raw material for plywood manufacturing instead of bonding multiple sheets of veneer.

[0005] In the past, plywood was made by bonding and compressing multiple layers of veneers formed by thinly slicing hardwoods such as lauan or various softwoods. Additionally, as building materials other than wood plywood, urethane foam panels and styrofoam panels, which are made by filling urethane foam or styrofoam between two sheets of steel, have been used as building materials for various wall and ceiling materials.

[0006] As environmental pollution has intensified recently, there is a global trend toward strengthening environmental protection policies. In particular, indiscriminately discarded waste plastic is identified as one of the major sources of environmental pollution; when waste plastic breaks down into microplastics and enters oceans and rivers, it serves as food for fish and birds, disrupting ecosystems and ultimately posing a serious threat to human health.

[0007] Accordingly, the issue of waste plastic disposal is emerging as a social issue, but currently, domestic waste plastics such as transparent plastics and polyethylene terephthalate (PET) are recycled on a limited basis, accounting for only about 10% of the total amount generated.

[0008] The remaining 90% of waste plastic is incinerated, landfilled, or dumped into the sea, which is a major cause of environmental pollution.

[0009] As plastics take at least several decades to decompose when landfilled and generate harmful gases that cause air pollution when incinerated, the circular utilization of waste plastics is emerging as a critical issue.

[0010] For example, the following patent document 1 discloses a ‘plywood having a grid-shaped plastic plate as the core material’.

[0011] A plywood having a grid-shaped plastic plate as a core material according to Patent Document 1 below is formed by integrally molding a grid-shaped plastic plate such that a top plate and a bottom plate are formed with flat plastic plates and a plurality of partitions are formed in a longitudinal row between the top plate and the bottom plate, and then applying adhesive to the upper and lower surfaces of the grid-shaped plastic plate and bonding a single sheet of wood veneer or multiple sheets in a longitudinal row onto the adhesive.

[0012] This type of plywood is formed by integrally molding a grid-shaped plastic plate, in which flat boards are used to form the top and bottom plates, and multiple partitions are formed in a longitudinal row between the top and bottom plates. Adhesive is applied to the upper and lower surfaces of the plastic plate, and a single veneer is bonded onto the adhesive, or multiple veneers are bonded in a longitudinal row. The veneers are primarily made of wood, but plastic or steel plates are used as a substitute when necessary.

[0014] Patent Document 2 below discloses a ‘method for manufacturing interior plywood’.

[0015] The method for manufacturing interior plywood according to Patent Document 2 below comprises the steps of: crushing waste plastic to prepare waste plastic flakes; manufacturing a plastic composition including the waste plastic flakes and the first plastic; extruding the plastic composition to manufacture a unit plate; and bonding the sides of two or more unit plates together with an adhesive composition to manufacture a plate-shaped intermediate molded body. Prior art literature

[0016] Korean Patent Publication No. 10-2021-0152159 Korean Patent Publication No. 10-2024-0084230 Korean Patent Publication No. 10-2006-0034256 The problem to be solved

[0017] The objective of the present invention is to solve the aforementioned problems by providing a method for manufacturing a grid-type plastic plywood using waste plastic and the plastic plywood said, wherein one or more materials selected from among hard PET, PP, and HDPE from among discarded plastics are melted at a high temperature, a flat rectangular bottom plate having a plurality of bottom plate protrusions formed on its upper surface and a flat cover plate of the same size as the bottom plate are injection molded, the bottom plate and the cover plate are bonded to produce a grid-type recycled plastic plywood, and a surface plate is bonded thereon to easily produce the plywood. means of solving the problem

[0018] To achieve the above-mentioned purpose, the method for manufacturing a grid-type plastic plywood using waste plastic according to the present invention comprises the following steps: selecting usable waste plastics among PET, PP, and HDPE, selecting only PET from the selected waste plastics, or selecting waste plastics composed of a mixture of PP and HDPE and two or three types, and melting them at 250°C, which is higher than the melting temperature of PET, to form a grid-type plastic bottom plate (110) and a cover plate (130) of the grid-type plastic to a predetermined size (S110); applying an adhesive layer to the upper surface of the bottom plate protrusion (111) of the bottom plate (110) formed in the molding step (S110), and then attaching the cover plate (130) to form a grid-type plastic plywood (S120); and applying an adhesive layer (131) to the upper surface of the cover plate (130), and then attaching a surface plate (150) to the adhesive layer (131) (S130).

[0019] The above molding step (S110) is performed as a continuous molding process to increase production efficiency.

[0021] Meanwhile, the method for manufacturing a grid-type plastic plywood using waste plastic according to the present invention comprises: a bottom plate (110) formed to a predetermined size; a bottom plate protrusion (111) formed to a predetermined height on the upper surface of the bottom plate (110) and spaced apart from the upper surface of the bottom plate (110) by a predetermined distance; a cover plate (130) attached to the upper surface of the bottom plate protrusion (111); and a surface plate (150) attached to the upper surface of the cover plate (130).

[0023] An adhesive layer (112) is formed on the upper surface of the lower plate protrusion (111) so that the cover plate (130) can be adhered thereto, and an adhesive layer (131) is formed on the upper surface of the cover plate (130) so that the surface plate (150) can be adhered thereto.

[0025] A thermosetting adhesive can be used to bond the lower plate (110) and the cover plate (130), thereby improving bond strength and durability.

[0027] The adhesive layer (131) is uniformly applied to the entire upper surface of the cover plate (130) to optimize the adhesive strength.

[0029] The height of the lower plate protrusion (111) can be set between 5mm and 10mm to increase the strength of the grid-like structure.

[0031] The above-mentioned molded bottom plate (110) and cover plate (130) can provide high strength and heat resistance through a cooling process.

[0033] The above adhesive uses an eco-friendly water-based adhesive, which can minimize the impact on the environment.

[0035] The above surface plate (150) may be coated with a UV blocking coating to enhance durability.

[0037] The lower plate (110) and the cover plate (130) are molded in different colors to facilitate visual distinction.

[0039] The above-mentioned grid-type plastic plywood may be additionally waterproofed so that it can be used as a building material. Effects of the invention

[0040] As described above, according to the method for manufacturing a grid-type plastic plywood using waste plastic and the plastic plywood according to the present invention, in the manufacture of plywood, waste plastic is utilized to injection mold the bottom plate and the cover plate, respectively, and bond them together with a protruding adhesive layer to easily produce a grid-type recycled plastic plywood. This simplifies the production process and reduces the production cost when manufacturing grid-type recycled plastic plywood.

[0041] In addition, while conventionally, to manufacture thick plywood, multiple veneers had to be bonded together, the thickness of the plywood can be freely adjusted by adjusting the thickness of the bottom plate and the cover plate or by adjusting the spacing of the bottom plate protrusions.

[0042] In addition, since multiple spaces are formed between the bottom plate and the cover plate by the bottom plate protrusions, it has a greater effect in blocking external heat conduction and superior sound insulation compared to ordinary plywood.

[0043] Furthermore, given the reality that massive amounts of waste plastic are generated globally and cause serious pollution, selecting rigid PET, PP, and HDPE from discarded plastics and utilizing them as materials for plywood manufacturing allows for the effective recycling and utilization of waste plastic, while also having a significant effect on pollution prevention. Brief explanation of the drawing

[0044] FIG. 1 is a process diagram illustrating a method for manufacturing a grid-type plastic plywood using waste plastic according to a preferred embodiment of the present invention. FIG. 2 is an exploded perspective view illustrating a grid-type plastic plywood using waste plastic according to a preferred embodiment of the present invention. FIG. 3 is a three-dimensional view illustrating a grid-type plastic plywood using waste plastic according to a preferred embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating a grid-type plastic plywood using waste plastic according to a preferred embodiment of the present invention. Specific details for implementing the invention

[0045] Below, with reference to the attached drawings, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention.

[0046] However, since the description of the present invention is merely an example for structural or functional explanation, the scope of the rights of the present invention should not be interpreted as being limited by the examples described in the text.

[0047] For example, since the embodiments can be modified in various ways and can take various forms, the scope of the present invention should be understood to include equivalents capable of realizing the technical concept.

[0048] Furthermore, since the purposes or effects presented in this invention do not imply that specific embodiments must include all of them or only such effects, the scope of the rights of this invention should not be understood as being limited by them.

[0049] In this specification, the embodiments provided are intended to make the disclosure of the invention complete and to fully inform those skilled in the art of the scope of the invention. The invention is defined only by the scope of the claims.

[0050] Accordingly, in some embodiments, well-known components, well-known operations, and well-known techniques are not specifically described to avoid the invention being interpreted ambiguously.

[0051] Meanwhile, the meaning of the terms described in this invention is not limited to their dictionary meanings and should be understood as follows.

[0052] Unless otherwise defined, all terms used herein have the same meaning as generally understood by those skilled in the art to which this invention pertains.

[0053] Terms defined in commonly used dictionaries should be interpreted as having meanings consistent with the context of the relevant technology, and should not be interpreted as having an ideal or overly formal meaning unless explicitly defined in the present invention.

[0055] Hereinafter, a method for manufacturing a grid-type plastic plywood using waste plastic according to a preferred embodiment of the present invention and the plastic plywood said will be described in detail with reference to the attached drawings.

[0056] A method for manufacturing a grid-type plastic plywood using waste plastic according to a preferred embodiment of the present invention comprises the steps of: selecting usable waste plastic among PET, PP, and HDPE; selecting only PET from the selected waste plastic, or selecting waste plastic composed of a mixture of PP and HDPE and two or three types; melting at 250°C, which is higher than the melting temperature of PET, to form a grid-type plastic bottom plate (110) and a cover plate (130) of a predetermined size (S110); applying an adhesive layer to the upper surface of the bottom plate protrusion (111) of the bottom plate (110) formed in the molding step (S110), and then attaching the cover plate (130) to form a grid-type plastic plywood (S120); and applying an adhesive layer (131) to the upper surface of the cover plate (130), and then attaching a surface plate (150) to the adhesive layer (131) (S130).

[0057] FIG. 1 is a process diagram illustrating a method for manufacturing a grid-type plastic plywood using waste plastic according to a preferred embodiment of the present invention.

[0058] The waste plastics used in the present invention are hard PET (polyethylene terephthalate), PP (polypropylene), and HDPE (High Density Polyethylene).

[0059] In other words, among the collected waste plastics, PVC (Polyvinyl Chloride) and LDPE (Low Density Polyethylene), which is mainly vinyl, are not used.

[0060] Waste plastics are classified and discharged into hard PET (polyethylene terephthalate), PP (polypropylene), HDPE (High Density Polyethylene), PVC (Polyvinyl Chloride), etc., and mainly vinyl-type LDPE (Low Density Polyethylene), styrofoam, and other plastics mixed with other materials.

[0061] Hard plastics are selected and used, including PET, which is the main raw material for PET bottles; PP, which is the raw material for caps; and HDPE, which is used for shampoo or detergent containers or children's toys.

[0062] PVC that emits harmful gases at high temperatures, LDP vinyl, styrofoam, and other plastics mixed with other materials are excluded from sorting.

[0063] In this way, by excluding PVC, LDPE, styrofoam, and other plastics, the waste plastic used in plywood has the effect of maintaining relatively uniform quality when manufacturing grid-type recycled plastic sheets.

[0064] That is, among PET, PP, and HDPE, usable waste plastics are sorted, and among the sorted waste plastics, only PET is selected and used, or waste plastics consisting of a mixture of PP and HDPE and two or three types are sorted.

[0065] When one or more of the selected PET, PP, and HDPE are selected and melted at around 250°C, which is slightly higher than the crystal melting temperature of PET (230°C), the PET melts, and PP and HDPE, which melt at a slightly lower temperature than PET, also melt together.

[0066] The reason it melts at around 250°C, which is slightly higher than PET, is that some impurities may be mixed in the waste plastic used as material.

[0067] FIG. 2 is an exploded perspective view illustrating a grid-type plastic plywood using waste plastic according to a preferred embodiment of the present invention, FIG. 3 is a perspective view illustrating a grid-type plastic plywood using waste plastic according to a preferred embodiment of the present invention, and FIG. 4 is a cross-sectional view illustrating a grid-type plastic plywood using waste plastic according to a preferred embodiment of the present invention.

[0068] As shown in FIGS. 2 to 4, the selected waste plastic is melted at 250°C, which is higher than the melting temperature of PET, to form a grid-shaped plastic bottom plate (110) and a cover plate (130) of a predetermined size (S110).

[0069] In this way, the molten mixture of one or more of PET, PP, and HDPE is formed with a plurality of lower plate protrusions (111) spaced at regular intervals on the upper surface of a flat rectangular lower plate (110).

[0070] In addition, a cover plate (130) made of a flat rectangular plate of the same size as the bottom plate (110) is injection molded.

[0071] By applying an adhesive layer (112) to the upper surface of the lower plate protrusions (111) that protrude in a longitudinal row on the upper surface of the lower plate (110) produced by injection molding in this manner, and attaching a cover plate (130) thereon, a grid-shaped raw plastic plywood is produced in which the lower plate (110) and the cover plate (130) are integrated.

[0072] An adhesive layer (112) is formed on the upper surface of the lower plate protrusion (111) so that the cover plate (130) can be adhered thereto, and an adhesive layer (131) is formed on the upper surface of the cover plate (130) so that the surface plate (150) can be adhered thereto.

[0073] An adhesive layer is applied to the upper surface of the lower plate protrusion (111) of the lower plate (110) formed in the above molding step (S120), and then the cover plate (130) is attached to form a grid-shaped plastic plywood (S120).

[0074] An adhesive layer (131) is applied to the upper surface of the cover plate (130), and then a surface plate (150) is attached to the adhesive layer (131) (S130).

[0075] A layer of adhesive (131) is applied to the upper surface of the grid-shaped plastic plywood produced in this way, and a wooden surface plate (150) is bonded thereto to manufacture the plywood.

[0076] The grid-shaped plastic plywood thus has a wooden surface plate (150) attached to its surface, so that the structure of the plywood with the wooden surface plate (150) attached to its surface can be obtained just like a regular plywood.

[0077] The grid-type plastic plywood according to the present invention has the effect of easily producing a grid-type plastic plywood, which is the main material of the plywood, by selectively collecting only hard PET, PP, and HDPE, melting one or more of the collected waste plastics at around 250°C, and then injection molding the bottom plate (110) and the cover plate (130) and bonding them with an adhesive layer (112).

[0078] Meanwhile, compared to the conventional method of manufacturing plywood by bonding multiple sheets of veneer, this method is simpler to manufacture and has the effect of enabling the production of plywood at a low cost by using waste plastic as the main material.

[0079] Currently, global plastic production reached 460 million tons as of 2020, but the recycling rate remains at around 9%, and a massive amount of waste plastic is mostly buried underground or incinerated, while a large amount of plastic flows into the ocean, causing severe environmental pollution.

[0080] Currently, methods such as physical, chemical, and thermal recycling are used to recycle waste plastics that are difficult to recycle. However, physical recycling is currently being used in extremely limited ways, such as by selecting only PET from recyclable waste plastics, washing and crushing it, compressing it into pellets, and using them as raw materials for automotive parts and home appliances.

[0081] The present invention has the effect of significantly reducing environmental pollution caused by waste plastics by enabling the use of medium-hard PET, PP, and HDPE waste plastics, which cause serious environmental pollution, as raw materials.

[0082] In addition, since a plurality of air layer spaces are formed between the bottom plate (110) and the cover plate (130) by the bottom plate protrusion (111), the sound insulation function is significantly improved compared to conventional plywood made by bonding multiple sheets together, and there is an effect of blocking heat from hot or cold temperatures from the outside of the structure.

[0083] The above grid-type plastic plywood comprises a bottom plate (110) formed to a predetermined size, bottom plate protrusions (111) formed to a predetermined height on the upper surface of the bottom plate (110) and spaced apart from the upper surface of the bottom plate by a predetermined distance, a cover plate (130) attached to the upper surface of the bottom plate protrusions (111), and a surface plate (150) attached to the upper surface of the cover plate (130).

[0084] The bottom plate (110) and the cover plate (130) are formed with the same size, and since the bottom plate (110) and the cover plate (130) are molded from waste plastic, the cost associated with manufacturing the plywood can be significantly reduced. Furthermore, since the cover plate (130) is attached to the upper surface of the bottom plate protrusion (111), the height of the bottom plate protrusion (111) can be freely formed.

[0085] That is, by forming the height of the lower plate protrusion (111) low, the height of the grid-shaped plastic plywood can be lowered, and by forming the height of the lower plate protrusion (111) high, the height of the grid-shaped plastic plywood can be freely adjusted.

[0086] In addition, by forming an internal empty space layer between the bottom plate (110) and the cover plate (130), it is possible to block inter-floor noise when used as a floor plate material, and to use it as a soundproofing material when used as a wall.

[0087] An adhesive layer (112) is formed on the upper surface of the lower plate protrusion (111) so that the cover plate (130) can be adhered thereto, and an adhesive layer (131) is formed on the upper surface of the cover plate (130) so that the surface plate (150) can be adhered thereto.

[0088] Since the above cover plate (130) is attached to the adhesive layer (112) applied to the upper surface of the lower plate protrusion (111), the working time for applying the adhesive layer (112) can be significantly reduced.

[0089] In addition, since the surface plate (150) is integrally attached to the adhesive layer (131) of the cover plate (130), the surface plate (150) can be firmly attached so that it does not separate from the cover plate (130).

[0090] The lower plate (110) and the cover plate (130) are made of waste plastic, and the surface plate (150) is made of wood.

[0091] The above surface plate (150) is made of wood having a certain thickness, and the surface plate (150) can produce the same surface condition as plywood made of wood.

[0092] In other words, the user perceives the bottom plate (110) and cover plate (130) made of waste plastic not to be exposed to the outside, and the surface plate (150) exposed to the outside as being made of wood, thereby creating the effect of a plywood made of ordinary wood.

[0094] Although the invention made by the inventors has been specifically described according to the above embodiments, the present invention is not limited to the above embodiments and can be modified in various ways without departing from the gist thereof. Explanation of the symbols

[0095] 110: Bottom plate 111: Bottom plate protrusion 112: Adhesive layer 130: Cover plate 131: Adhesive layer 150: Surface plate

Claims

Claim 1 A method for manufacturing a grid-type plastic plywood using waste plastic comprises the steps of: selecting usable waste plastics among PET, PP, and HDPE; selecting only PET from the selected waste plastics, or selecting waste plastics composed of a mixture of PP and HDPE and two or three types; melting the selected waste plastics at 250°C, which is higher than the melting temperature of PET, to form a grid-type plastic bottom plate (110) and a cover plate (130) of a predetermined size (S110); applying an adhesive layer to the upper surface of the bottom plate protrusion (111) of the bottom plate (110) formed in the molding step (S110), and then attaching the cover plate (130) to form a grid-type plastic plywood (S120); and applying an adhesive layer (131) to the upper surface of the cover plate (130), and then attaching a surface plate (150) to the adhesive layer (131) (S130). A method for manufacturing a grid-type plastic plywood using waste plastic, comprising Claim 2 A method for manufacturing a grid-type plastic plywood using waste plastic, wherein, in claim 1, the molding step (S110) is performed as a continuous molding process to increase production efficiency. Claim 3 A grid-type plastic plywood made using waste plastic manufactured by the method for manufacturing a grid-type plastic plywood described in claim 1, wherein the grid-type plastic plywood comprises: a bottom plate (110) formed to a predetermined size; a bottom plate protrusion (111) formed to a predetermined height on the upper surface of the bottom plate (110) and spaced apart from the upper surface of the bottom plate (110) by a predetermined interval; a cover plate (130) attached to the upper surface of the bottom plate protrusion (111); and a surface plate (150) attached to the upper surface of the cover plate (130). Claim 4 A grid-type plastic plywood made using waste plastic, characterized in that, in paragraph 3, an adhesive layer (112) is formed on the upper surface of the lower plate protrusion (111) so that the cover plate (130) can be adhered thereto, and an adhesive layer (131) is formed on the upper surface of the cover plate (130) so that the surface plate (150) can be adhered thereto. Claim 5 A grid-type plastic plywood made from waste plastic, characterized in that, in claim 4, a thermosetting adhesive is used to bond the bottom plate (110) and the cover plate (130), thereby improving bond strength and durability. Claim 6 A grid-type plastic plywood made from waste plastic, characterized in that, in claim 4, the adhesive layer (131) is uniformly applied to the entire upper surface of the cover plate (130) to optimize adhesive strength. Claim 7 A grid-type plastic plywood made from waste plastic, characterized in that, in claim 4, the height of the lower plate protrusion (111) is set between 5mm and 10mm to increase the strength of the grid-type structure. Claim 8 A grid-type plastic plywood made from waste plastic, characterized in that, in claim 4, the molded bottom plate (110) and cover plate (130) provide high strength and heat resistance through a cooling process. Claim 9 A grid-type plastic plywood made from waste plastic, characterized in that, in paragraph 4, the adhesive used is an environmentally friendly water-based adhesive to minimize environmental impact. Claim 10 In paragraph 3, the above surface plate (150) is characterized by having a UV blocking coating applied to enhance durability, a grid-type plastic plywood made of waste plastic. Claim 11 In paragraph 3, the bottom plate (110) and the cover plate (130) are molded in different colors to facilitate visual distinction, and the grid-shaped plastic plywood made using waste plastic. Claim 12 In paragraph 3, the grid-shaped plastic plywood made from waste plastic is characterized by having an additional waterproofing treatment so that it can be used as a building material.

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