KR102139014B1 - Method for manufacturing complex resin material for bicycle frame having excellent durability and light weight property - Google Patents

Abstract

The present invention relates to a composite resin molding material and a method of producing the same, wherein the composite resin molding material is composed of a resin having a low specific gravity and excellent strength, and thus is capable of forming, via injection molding, a bicycle frame that is light-weight and has a high durability with low manufacturing costs and various colors. The composite resin molding material of the present invention is produced through the steps of: mixing 88-96 wt% of polyester glycol (PETG) resin chips, 1-9 wt% of polyolefin (POE) resin chips, 1.5 wt% of a heat stabilizer for preventing the resin from degrading at high temperatures, 0.5 wt% of an anti-foaming agent, 1.0 wt% of a surfactant, and 0.3-2 wt% of color resin chips; melting the mixed resin chips into a resin mixture by heating; and extruding the melted resin mixture, followed by cooling and drying the same.

Description

Method for manufacturing composite resin molding material for bicycle frame having excellent durability and light weight, and composite resin molding material manufactured thereby {Method for manufacturing complex resin material for bicycle frame having excellent durability and light weight property}

The present invention relates to a composite resin molding material that can be molded into a bicycle frame, and more specifically, it is made of excellent resin with low specific gravity and light weight, high durability through injection molding, and low production cost and various colors of bicycles. It relates to a composite resin molding material capable of manufacturing a frame and a method of manufacturing the same.

Bicycles are not just a simple means of transportation, but are becoming a new means of transportation in the city, and the range of use is expanding, such as use for leisure trips up and down the mountain or traveling long distances. In particular, industrial environments such as high oil prices due to exhaustion of fossil fuels and CO ₂ emission regulations to cope with climate change are changing, and thus demand for bicycles, which are non-motorized, pollution-free, and eco-friendly transportation, is increasing significantly.

In the bicycle, a front frame and a rear frame form a body, and wheels are respectively connected to the lower portion of the frame, and a saddle that can be seated by a user is installed in the center to be adjustable. The bicycle frame corresponding to the main configuration that determines the strength and weight of the bicycle is largely composed of the front frame and the rear frame. In general, the front frame has a structure in which the head tube and seat tube are connected and supported by the top tube and the down tube. have.

Such a bicycle frame has been developed to have a high tensile strength and light weight, and the Korean Patent Publication No. 2015-0061048 discloses a bicycle frame made of titanium. In addition to titanium, metals having excellent physical properties such as chromium molybdenum alloy steel and stainless steel are used.

In addition, recently, a bicycle frame made of carbon fiber reinforced plastic has been released as disclosed in Korean Patent Application Publication No. 2016-0081266, and such a bicycle is light in weight and has excellent driving comfort, so that consumer satisfaction is very high.

However, the bicycle frame made of carbon fiber reinforced plastic has a high production cost, which makes it difficult to mass-produce, and metal materials and carbon fiber reinforced plastic have limitations in color production.

Republic of Korea Patent Publication No. 10-2015-0061048 (Titanium bicycle frame, titanium bicycle frame manufacturing method) Republic of Korea Patent Publication No. 2016-0081266 (Bicycle frame using carbon fiber reinforced composite material)

Accordingly, the present invention has the object to provide a molding material for a bicycle frame capable of mass production at low production cost, light weight and durability, and capable of producing various colors, and a method of manufacturing the same.

In order to solve the above problems, the present invention is 88 to 96% by weight of polyester glycol (PETG) resin chip, 1 to 9% by weight of polyolefin (POE) resin chip, 0.5 to 1.5% by weight of heat stabilizer, 0.3 to 0.7 Mixing a weight percent antifoaming agent, 0.5 to 1 weight percent surfactant, and 0.3 to 2 weight percent colored resin chips, heating the mixed resin chips to melt the resin mixture, and extruding the melted resin mixture. It provides a method for manufacturing a composite resin molding material for a bicycle frame comprising a step of cooling and drying.

In the present invention, the polyolefin resin chip is a polyethylene resin, a polyethylene copolymer resin chip, a polypropylene resin chip, a polypropylene copolymer resin chip, or a resin chip in which they are mixed.

In addition, in the present invention, after the resin chip is heated to 250 to 260°C and melted, the melted resin mixture is extruded while being stirred by a rotating screw.

And, the present invention provides a composite resin molding material for a bicycle frame manufactured by the above-described method.

The molding material of the present invention is made of solid chips of excellent resin material having a lower specific gravity than metal and can be manufactured to produce a lightweight and high-durability automobile frame at low production cost through injection molding. In case of a safety accident, the shock can be absorbed, and it can be expressed in various colors to create an aesthetic bicycle frame.

1 is a flow chart of a method for manufacturing a composite resin molding material for a bicycle frame according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

This embodiment is provided to more fully describe the present invention to a person having average knowledge in the art, and in the description of the embodiment, in principle, known functions or known configurations, such as related known functions, are already provided. If it is determined that the technical features of the present invention may be unnecessarily obscured by those skilled in the art, the detailed description thereof will be omitted.

1 is a flow chart showing a method of manufacturing a composite resin molding material for a bicycle frame according to the present invention, the present invention is a step of mixing a polyester glycol (PETG) resin chip, polyolefin (POE) resin chip, additives and colored resin chip (S110), heating the mixed resin chip to melt the resin mixture (S120), and cooling the melted resin mixture to extrude (S130).

Polyester glycol (PETG) to be mixed in step S110 is prepared by mixing the polymer material of polyester (PET) and glycol (Glycol). As glycol, ethylene glycol (Ethylene Glycol, EG), Diethlylene Glycol (DEG), and tripropylene glycol (Triprophylene Glycol, TPG) can be used, and polyester and glycol are mixed in a weight ratio of 1: 0.5 to 5.0. Polyester glycol (PETG) can be prepared. Polyester glycol (PETG) is formed of solid chips to facilitate storage or extrusion.

The polyester glycol (PETG) produced as described above has excellent tensile strength, impact strength, and flexural strength, as well as excellent chemical resistance, so that it is not damaged or deformed even when exposed to the external environment, and is also durable and has no whitening phenomenon. Can be molded back. Therefore, a colored resin chip may be added to polyester glycol (PETG), which is highly transparent, to express color. The colored resin chip is manufactured by including dyes and dispersants of various colors, and various colors can be expressed by the color of the added dye, so that the bicycle frame can be designed in various colors.

Polyolefin (POE) mixed with polyester glycol (PETG) may be a polyethylene resin, a polyethylene copolymer resin, a polypropylene resin, a polypropylene copolymer resin, or a resin mixed with them. Polyolefin (POE) is added to improve the moldability and elasticity of polyester glycol (PETG), and is added at 1 to 9% by weight to 88 to 96% by weight of polyester glycol (PETG). When the polyolefin (POE) exceeds 9% by weight, the moldability and tensile strength are lowered and defects are easily generated due to a temperature difference. When the polyolefin (POE) is less than 1% by weight, elasticity of the composite resin molding material deteriorates. Polyolefin (POE) is formed of a solid chip like polyester glycol (PETG), and a colored resin chip is added to the mixed resin chip for color expression.

The colored resin chip is preferably 0.3% by weight to 2% by weight relative to the total weight of the molding material. If the colored resin chip is less than 0.3% by weight, it is difficult to develop color, and when it exceeds 2% by weight, there is no longer any effect of color development, and the extrusion moldability of the molding material deteriorates.

In this way, an additive for improving extrusion moldability is mixed with a polyester glycol (PETG) resin chip, a polyolefin (POE) resin chip, and a colored resin chip. As an additive, a thermal stabilizer to prevent the resin from being destroyed from high heat, an antifoaming agent and a surfactant are used to stably mold the composite resin molding material.

Heat stabilizers trimethylphosphate, triethyl phosphate, tributyl phosphate, tributoxyethyl phosphate, tricresyl phosphate, triaryl phosphate isopropyllay One or two or more selected from triryl phosphate isopropylated and hydroquinone bis-(diphenyl phosphate) may be used. Further, as the antifoaming agent, one or two or more of polydimethylsiloxane-based, modified polydimethylsiloxane-based, non-silicone-based polymer solutions, and mineral oil-based polymers may be mixed and used. In addition, as the surfactant, known ionic and nonionic surfactants can be used. Based on the total weight, 0.5 to 1.5% by weight of the heat stabilizer is added, 0.3 to 0.7% by weight of the antifoaming agent, and 0.5 to 1% by weight of the surfactant.

In step S120, a mixed resin chip in which a polyester glycol (PETG) resin chip, a polyolefin (POE) resin chip, and a colored resin chip is mixed is heated to melt into a resin mixture. A screw extrusion molding machine may be used to melt and evenly mix the resin chips to be mixed in this way. When the resin chip mixed into the inner space of the screw pressure molding machine is introduced, it is heated and melted at 250 to 260°C by a heater to form a paste, and is homogeneously mixed by rotation of the screw.

In step S130, the molten resin mixture is extruded and dried by cooling, and a screw rotating inside the screw pressure molding machine advances in a uniaxial direction to press and extrude the resin mixture in a paste state. After cutting the extruded resin mixture to a predetermined size, cooling and drying the composite resin molding material is completed.

The examples and comparative examples of the present invention prepared as described above will be described below.

<Example>

Polyester glycol (PETG) resin chip 89% by weight, polypropylene resin chip 7% by weight, stabilizer 1.5% by weight, antifoaming agent 0.5% by weight, surfactant 1% by weight, carbon black resin chip 1% by weight inside space of the screw pressure molding machine And melted by heating to 250°C. Then, the resin mixture in the molten paste state was stirred by rotating the screw, and then the screw was advanced and discharged to one side. The discharged resin mixture was cut and dried to a length of 2 cm to prepare a composite resin molding material.

<Comparative Example 1>

A composite resin molded material was prepared in the same manner as in Example except that 95.5% by weight of a polyester glycol (PETG) resin chip and 0.5% by weight of a polypropylene resin chip were mixed.

<Comparative Example 2>

A composite resin molding material was prepared in the same manner as in Example except that 90% by weight of a polyester glycol (PETG) resin chip and 6% by weight of a polypropylene resin chip were mixed.

The results of measuring the strength (tensile strength, impact strength, flexural strength) and flexural modulus of Examples and Comparative Examples 1 and 2 thus prepared are shown in Table 1 below.

division Example Comparative Example 1 Comparative Example 2 Tensile strength (MPa) 72.7 73.1 49.5 Impact strength (J/m) 65.3 66.4 54.6 Flexural strength (MPa) 113.6 103.2 114.4 Flexural modulus (GPa) 6.3 3.4 6.4 color black Transparency Transparency

As shown in Table 1, the embodiment of the present invention was excellent in tensile strength, impact strength, as well as flexural strength and flexural modulus. Comparative Example 1 had excellent tensile strength and impact strength, but the flexural strength and flexural modulus were low. Comparative Example 2 had good flexural strength and flexural modulus, but low tensile strength and impact strength. Further, unlike Comparative Examples 1 and 2, which were not transparently colored, the examples were expressed in black.

As described above, the molding material of the present invention is made of a solid resin chip having a low specific gravity and high strength, so that a lighter and more durable automobile frame can be manufactured at low production cost through injection molding, and the elastic modulus is also excellent. In the event of a safety accident, such as losing paper, the shock can be cushioned, and the desired color can be expressed to create an aesthetic bicycle frame.

The present invention described above is not limited to the described embodiments, and it is obvious to those skilled in the art that various modifications and modifications can be made without departing from the spirit and scope of the present invention. Therefore, such modifications or modifications will have to belong to the claims of the present invention.

Claims (4)

In the manufacturing method of the molding material for the bicycle frame,
88~96% by weight of polyester glycol (PETG) resin chip, 1~9% by weight of polyolefin (POE) resin chip, 0.5~1.5% by weight of heat stabilizer, 0.3~0.7% by weight of antifoaming agent, 0.5~1% by weight Mixing a surfactant and a colored resin chip of 0.3 to 2% by weight;
Heating the mixed resin chips to melt the resin mixture; And,
Method of manufacturing a composite resin molding material for a bicycle frame comprising; extruding the molten resin mixture to cool and dry. According to claim 1,
The polyolefin resin chip,
Polyethylene resin, polyethylene copolymer resin chip, polypropylene resin chip, polypropylene copolymer resin chip, or a method of manufacturing a composite resin molding material for a bicycle frame, characterized in that a mixed resin chip. According to claim 1,
A method of manufacturing a composite resin molding material for a bicycle frame, wherein after melting the resin chip by heating at 250 to 260°C, the molten resin mixture is extruded while being stirred by a rotating screw. A composite resin molding material for a bicycle frame manufactured by the method of any one of claims 1 to 3.

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