KR19990010677A - How to Play Bumper - Google Patents

Abstract

The present invention relates to a method for regenerating a bumper for a vehicle, and more particularly, a paint defect or a paint coated on a waste bumper, which is used as an automobile exterior part, as N-methyl-2-pyrrolidone (hereinafter referred to as NMP). The present invention relates to a method for regenerating a bumper for automobiles which is improved to be recycled by raising physical properties of the regenerated thermoplastic resin to a level equivalent to that of the new resin by effectively removing the same using treatment, physical stirring, and heat.

Description

How to Play Bumper

The present invention relates to a method for regenerating a bumper for a vehicle, and more particularly, to effectively remove a paint defect or a paint applied to a waste bumper, which is used as an automotive exterior part, by effectively removing NMP treatment, physical stirring, and heat. The present invention relates to a method for regenerating bumpers for automobiles, which is improved to be recycled by raising physical properties of thermoplastic resins to the same level as new resins.

In cars, bumpers not only protect the body in minor collisions, but also enhance the body appearance. Polyurethanes, polycarbonates and polybutylene terephthalate alloys are used as such bumper materials for automobiles, but in recent years, the use of thermoplastic polyolefin resins (TPO resins) such as polypropylene, which is particularly easy to recycle, has been increasing.

Bumpers made of these materials are usually painted and used in the same color as the car body for the purpose of unity with the car body, high-quality feeling, and the like. In general, polyurethane, polycarbonate, and polybutylene terephthalate alloys are coated without a separate pretreatment process, and thermoplastic polyolefin resins, which are nonpolar resins, have a low reactivity with paints to improve coating adhesion. (primer) is treated on the surface, and then the coating material, which is a thermosetting resin, is treated. When the paint, which is a thermosetting resin, is mixed during regeneration of the waste bumper, it causes deterioration of physical properties such as elongation and impact strength of the resin, and the coating film is exposed to the outside of the molded article to reduce the appearance quality of the molded article. Accordingly, a technique for removing the coating film during bumper regeneration is essential, and various techniques have been disclosed so far.

As a technique developed so far, there is a method of removing the coating film from the bumper surface by a shot blast, but in this case, it is difficult to remove the coating film of the curved portion.

Japanese Patent Laid-Open Publication Nos. Hei 6-226742 and Hei 7-108800 disclose a technique of peeling a flame onto the surface of a bumper so that the coating film and the substrate can be peeled off, but such a method is also difficult to treat the curved portion, and the flame There is a problem that the thermoplastic substrate is easily melted or deteriorated during spinning, and mass production is difficult.

On the other hand, the coated bumper is pulverized and deposited in an organic solvent to remove the coating film. Japanese Patent Laid-Open Publication Nos. Hei 6-31731 and Hei 5-185024 also use a pyridine solution or a saturated sodium hydroxide solution of methanol. Techniques for removing are disclosed. However, this method has a problem in that the cost of organic solvents or chemicals required to remove the coating film is expensive and a post-treatment process of the solvent used after removing the coating film, for example, a wastewater treatment facility, is required.

In order to solve the problem of the conventional film removal method using the technique of pulverizing the conventional bumper as described above and treating with an organic solvent, by physically stirring with immersion and heat treatment in NMP solution and then crushing and extruding, It is an object of the present invention to provide a method for regenerating a bumper for automobiles, which is harmless to the environment by recovering and reusing NMP without affecting the physical properties.

The present invention is a method of regenerating a bumper by removing the coating film of the waste bumper, characterized in that the waste bumper is deposited with NMP solution and stirred together with heat treatment to remove the coating film, followed by grinding and re-extrusion molding.

This will be described in more detail as follows.

The present invention removes the thermosetting coating film by immersing the waste bumper in NMP solution together with immersion and heat treatment, and then pulverizes and re-extrudes the physical properties of the recycled resin to be equal to or higher than that of the new resin and recovers and reuses NMP. The present invention relates to a method of regenerating a bumper that is harmless to the environment.

The present invention first secures a waste bumper or a defective painting product to a fixing mechanism, and then removes foreign substances such as dust adhered to the outer surface of the bumper, which are caused by deterioration of physical properties when incorporated into the regeneration bumper, by using high pressure air.

Then, deposit a waste bumper or defective product in a stirrer containing 95% or more NMP solution, raise the temperature in the vessel to 80 ~ 90 ℃ and stir the solution at 700 ~ 1200 rpm for 7 to 15 minutes Remove it. Here, NMP dissolves a primer layer and cancels the bond force between resin and a coating film, and isolates a coating film. If the reaction temperature is less than 80 ℃ there is a problem that the deposition time is long, if it exceeds 90 ℃ there is a risk of NMP evaporation is not preferred. In addition, agitation is performed to reduce the separation time of the coating film. However, if the stirring speed is less than 700 rpm, sufficient shear force cannot be given between the resin and the paint. If the stirring speed is higher than 1200 rpm, the temperature in the solvent may increase rapidly due to friction. Not desirable

Next, the bumper from which the coating film has been removed is lifted onto the surface of the stirrer to remove the NMP solution buried on the surface of the bumper using pressurized air of 5 to 15 kgf / cm 2 or more. This is because the second contamination occurs when the NMP solution is wiped off with another solvent.

In this way, a bumper from which impurities such as NMP and other impurities are removed together with the coating film is put into a grinder in the same manner as in the conventional method, and pulverized to a size of 5 to 10 mm, and the pulverized product is compounded with a zinc-based heat stabilizer in a twin screw extruder to produce recycled pellets. The new bumper is manufactured by injection molding.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1

Waste bumper made of polyolefin resin is removed by using high pressure air to remove foreign substances such as dust on the surface, and this is deposited in a stirrer containing NMP solution of more than 95% concentration and then stirred at 85 ℃ and average stirring speed 900 ~ 970 rpm. After the removal of the NMP solution, the remaining NMP solution was also removed by applying high pressure air, and put in a pulverizer in the same manner as in the conventional method, pelletized by pulverization and a twin screw extruder, and a new bumper was manufactured.

Comparative Example 1

A new bumper was manufactured in the same manner with the same polyolefin-based resin as in Example 1. However, the temperature conditions of the NMP solution in the stirrer were carried out at room temperature.

Comparative Example 2

A new bumper was manufactured in the same manner with the same polyolefin-based resin as in Example 1. However, stirring was not performed after immersion in NMP solution.

Comparative Example 3

A new bumper was manufactured by the method of pulverizing, extruding, and molding according to a conventional method with the same polyolefin-based resin as in Example 1 without removing the coating film.

Experimental Example

By injection molding the specimen of the new bumper prepared according to the Examples and Comparative Examples 1 to 3 by measuring the tensile strength, elongation, flexural modulus, impact strength at -10 ℃, heat deformation temperature (HDT) and paintability The results are shown in Table 1 below.

Elongation and tensile strength were measured by ASTM D 638 method, impact strength was measured by ASTM D 256 method, flexural modulus was measured by ASTM D 790 method, and heat deflection temperature (HDT) was measured by ASTM D 648 method. The toughness was measured by the JIS K 5400 method.

division Example Comparative Example One 2 3 Tensile Strength (㎏ / ㎠) 320 250 250 200 % Elongation More than 600 220 190 25 Flexural modulus (㎏ / ㎠) 7500 7700 8500 9000 Impact strength (kgcm / cm) 10.5 5.2 6.4 2.9 Heat Deflection Temperature (HDT (℃)) 107 100 98 82 Paintability ○ △ △ × (Note) ○: Good △: Normal ×: Poor

The present invention can prevent the mixing of paint by removing the coating film of the waste bumper to prevent the mixing of the paint to obtain a regeneration bumper with little deterioration of physical properties, and also by using NMP having a boiling point of 220 ℃ to reduce evaporation in the air and recover it Not only can it be reused, but a small amount of NMP remaining in the extruder reacts with the remaining coating film to be decomposed to the environment to obtain a harmless effect.

Claims (3)

A method of regenerating a bumper by removing a coating film of a waste bumper, wherein the waste bumper is deposited in a N-methyl-2-pyrrolidone solution and stirred together with a heat treatment to remove the coating film, followed by grinding and re-extrusion molding. A method of regenerating a bumper for automobiles. The method of claim 1, wherein the heat treatment temperature of the N-methyl-2-pyrrolidone solution is 80 ~ 90 ℃. The method of claim 1, wherein the stirring speed of the N-methyl-2-pyrrolidone solution is 700 to 1200 rpm.