JPH0584746A - Method for peeling, separating and recovering coated film of polypropylene resin molded product - Google Patents

Abstract

PURPOSE:To recover a resin base material as a reclamation raw material by roughly grinding a polypropylene resin having a film applied thereto and adding water and methylene chloride to heat the ground matter under stirring to peel off the film therefrom. CONSTITUTION:A raw material obtained by roughly grinding a polypropylene resin molded product having a film applied thereto and methylene chloride are received in a container equipped with a stirrer and water is added to the container in order to reduce the volatilization of the solvent. The resulting mixture is heated to a temp. of about 40 deg.C equal to or below the b.p. of methylene chloride to be stirred at a high speed. After the film is peeled off by the dissolution or swelling of a primer, stirring is stopped. The peeled film is settled and a polypropylene resin floats. This floating matter is recovered to be used as a reclamation raw material.

Description

Detailed Description of the Invention

This invention reuses a coated polypropylene molded article such as an automobile bumper, so that the coating film is peeled off and the peeled coating film piece is automatically separated to recycle the resin substrate. The present invention relates to a coating film peeling automatic separation and collection method that can be collected as a raw material.

[0002]

2. Description of the Related Art In many polypropylene molded products such as automobile bumpers, the surface of which is coated and it is difficult to remove the coating by peeling it off, so that the fields in which the base resin can be reused have been limited. That is, when coating film pieces are mixed in the recycled product, cracking and impact resistance are reduced.

[0003]

[Problems to be Solved] An automobile bumper, which is a large-sized molded product of polypropylene resin, has a urethane-based paint applied on the surface of the molded product through a chlorinated polyethylene-based primer. Therefore, simply scrapping a scrap car bumper cannot be a recycled material. In the present invention, the coating film adhering to the coarsely pulverized product is peeled off in the solution, and the specific gravity difference is used to further remove the base material (Spg = 0.918 to 0.92) and the peeled coating film (Spg = 1. It is intended to provide a method capable of easily recovering a substrate by automatically separating 5-1.8).

[0004]

In the present invention, a chlorinated hydrocarbon, particularly methylene chloride, is effective as a solvent or a swelling agent for a chlorinated polyethylene-based primer. Further, it is effective to allow a small amount of water to coexist for the purpose of reducing or preventing methylene chloride from being vaporized during the treatment process.

Further, in order to promote the contact and peeling of the primer, it is necessary to heat the solvent to a temperature below the boiling point of the solvent and mechanically stir it.

Therefore, the container used in the present invention is a jacketed dissolution vessel into which a stirrer can be charged or which is fixedly provided. In this container, the upper surface of the solvent layer is covered with a water vapor diffusion preventing layer. The roughly pulverized raw material with a coating film may be charged in this state, but a solvent and water may be sequentially added to the raw material.

[0007]

[Example] A raw material 30k roughly crushed by a crusher into an appropriate size (for example, 0.5 cm ³ or less) and shape
g into the container 1, and methylene chloride (Spg = 1.3
(8, boiling point 40.2 ° C.) 100 L, and water 10 L were added.
With the lid 2 on, warm water is supplied to the jacket to heat the jacket to 40 ° C., and the speed of the stirrer 3 is set to 500 rpm. p. m. Was stirred for 1 hour. By this stirring, the water-soluble substance adhering to the surface of the ground pieces is dissolved in water, and the fixed portion sinks together with the coated pieces. Further, the oil content is transferred into the solvent. After that, the heating is stopped, and 20 r. p. m. After stirring for 10 minutes, the stirring was stopped and the mixture was allowed to stand. After 30 minutes, the liquid layer becomes the first two-layer state and the coating film piece 6 (white coating film Spg = 1.5 to 1.8) having a specific gravity larger than that of methylene chloride is formed on the container bottom portion 4.
Settled in. The base material (Spg = 0.918-0.92) from which the coating film was removed floats on the upper layer and the water layer of the solvent layer.

The recovery of the floating base material can be easily performed by pouring water and overflowing in addition to removing the squeeze, and the recovered material can be used as a recycled raw material immediately after drying the water content. The sedimented coating film piece is placed in an appropriate receiver together with a part or all of methylene chloride by opening the discharge valve 5 and then filtered. The dry weight of the coating film piece was about 135 g. (Removal rate about 92
%) It is possible to remove up to 95% depending on the treatment time. Of course, methylene chloride can be used again.

[0009]

[Effect] According to the present invention, the base resin and the coating film can be easily separated by automatically separating them in a solution by utilizing the difference in specific gravity between them, and the collected pieces are washed with water and a solvent, so that they can be regenerated as they are. It can be a raw material. Further, since the upper surface of the solvent is covered with the water layer, there is also an advantage that the solvent is less likely to vaporize.

[Brief description of drawings]

FIG. 1 is a sectional view of a container

[Explanation of symbols]

 3 is a stirrer 5 is a discharge valve 6 is a strip of coated film

Claims (1)

[Claims] 1. A coating primer obtained by roughly pulverizing a polypropylene resin molded product, water and methylene chloride in a container equipped with or capable of being charged with a stirring blade, heated to about 40 ° C., and coated under high speed stirring. Is dissolved or swelled to peel off the coating film, and then the stirring is stopped to allow the peeled coating film to settle at the bottom of the container, and the coarsely pulverized material floating on the liquid surface is recovered as a raw material for regeneration. A method for separating and collecting coating films from polypropylene resin molded products.