JPH0332774A - Painting method for resin molding - Google Patents

Abstract

PURPOSE:To form a film of a prescribed film thickness on a base material by measuring a specified amt. of paint from a tank, supplying the paint by a discharge pump to the storage part of a spray gun and completely applying the paint of this storage part in one cycle. CONSTITUTION:The paint P of the amt. necessary for obtaining the film of one resin molding is measured by the discharge pump 6 which simultaneously executes a measuring stage and a supplying stage and is supplied into a cup 12a of the spray gun 12. Further, an operator uniformly executes many times of coating until the paint P in the cup is completely used in the coating stage. The painting operation is carried out with the above mentioned operation as one cycle, by which the need for counting the number of coating is eliminated, unlike the conventional system to control the number of coating. The mis- counting by the operator is, therefore, obviated and further, the film of the prescribed film thickness satisfying a standard value is surely formed without having a fluctuation in the discharge rate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for painting resin molded products, and more specifically, paint stored in a paint tank is supplied to a spray gun, and the paint is sprayed by operating the spray gun. The present invention relates to a method of forming a film by spraying the same on the base material of a resin molded product many times.

[Prior Art] Conventionally, as a method of painting this type of resin molded product, there is a method of forming a film on the surface of a polyurethane resin base material (see Japanese Patent Application Laid-Open No. 60-34814). When this coating method is applied to the pads of wheels, the polyurethane paint used in this coating method generally has a short pot life and is highly separable, making it unsuitable for handling large amounts of paint. Therefore, in order to be able to supply the paint little by little, it was necessary to apply the paint to the base material many times using a cup-type spray gun to ensure a predetermined film thickness.

In other words, for example, if a film thickness of about 3 μm can be obtained with one coating, and the desired film thickness standard is 20 μm or more, the film thickness of this standard value can only be obtained by repeating the coating process 7 times. This work was considered one cycle. For this reason, an indeterminate amount of paint for seven or more applications is supplied into the spray gun cup, and the operator counts the number of times the paint is applied in order to obtain a film with a thickness that satisfies the above-mentioned standard values. A method of managing the number of times the event is performed has been adopted.

[Problems to be Solved by the Invention] However, according to such a number-of-times management system, an operator may miscount the number of times of application and stop the application operation after a number of times less than the prescribed number of seven times, for example, six times. In this case, there is a problem that only a film having a thickness less than the standard value can be formed. Furthermore, there was also the problem that a coating with a thickness less than the standard value could be formed due to variations in the discharge amount due to changes in the paint in the cup.

The purpose of the present invention is to eliminate the need for operators to manage the number of coatings, to prevent variations in coating thickness due to miscounting of the number of coatings or variations in the amount of spraying, and to ensure that a coating of a predetermined thickness is deposited on the substrate. An object of the present invention is to provide a method for coating a resin molded article that can be formed.

[Means for Solving the Problems] Therefore, in order to achieve the above object, the present invention supplies paint stored in a paint tank to a spray gun, and by operating the spray gun, the paint is applied to a resin molded product. In a coating method in which a film is formed by spraying multiple times on a base material, a measuring step of measuring an amount of paint from a paint tank to form a film of a predetermined thickness on one base material, and the measured paint A resin molding process consisting of a supply process in which the paint is supplied to the reservoir of a spray gun by a discharge pump, and a coating process in which the paint supplied to the reservoir is completely applied and a coating of a predetermined thickness is formed on the base material in one cycle. The gist is how to paint products.

[Operation: Measure the amount of paint from the paint tank to form a film of a predetermined thickness on one substrate, supply the paint to the reservoir of the spray gun by the discharge pump, and spray in one cycle. By completely applying the paint in this reservoir, a film having a predetermined thickness is formed on the base material. Therefore, the operator can form a coating having a predetermined thickness on the substrate by repeating coating until the paint supplied to the storage section runs out, without counting the number of coatings.

[Example] Hereinafter, an example in which the present invention is embodied in a method of forming a film on the surface of a polyurethane resin base material constituting a pad of a steering wheel of an automobile will be described based on the drawings.

First, the outline of the equipment used to paint the surface of the base material constituting the pad will be approximately 1.
In a paint tank 1 having a capacity of 1, a paint P consisting of a urethane paint, methyl ethyl ketone as a diluent, and additives such as pigments is stored in a mixed state. In the paint P in the paint tank L, there is a pipe 3 connected to a pressure source 2.
The end of the pipe 3 is guided so that compressed air supplied from the pressure source 2 is blown into the paint P from the end of the pipe 3. Therefore, the paint P is stirred by the blown air, and sedimentation of the pigment is prevented. The piping 3 is provided with a residual pressure valve 4 for maintaining a constant air pressure in the paint tank 1, and a shutoff valve 5 for stopping the supply of compressed air to the paint tank 1, which can be opened and closed. It is set in.

A suction side end 6a of a variable displacement discharge pump 6 is connected to the paint tank l. This discharge pump 6 is connected to the pressure source 2 via a directional valve 7 and a first branch 10.
The piston 9 in the cylinder 8 reciprocates with the compressed air from the same pressure B2, and the paint P in the paint tank 1 is sucked in a certain amount at a time to the discharge side end 6b.
It is designed to be discharged from In this example, 18 to 5 Qmj! Using a discharge pump 6 of a type capable of discharging paint of 23 ml, which is the amount necessary to obtain a film with a thickness of 20 μm or more,
The discharge amount of the discharge pump 6 was set.

On the other hand, a spray gun 12 is connected to the first branch passage 10 via a second branch passage 11 .

This spray gun 12 is equipped with a cup 12a as a reservoir, and has a discharge side end 6 that is connected to the discharge pump 6.
A transport path 13 extending from b is connected to this cup 12a. Note that the capacity of this cup 12a is 70 ml. By operating the switch 12b of the spray gun 12, the compressed air causes the paint P in the cup 12a to be sprayed little by little in the form of mist.

The spray gun 12 is mounted on a mounting table (not shown) when not in use, and the cassop 12a
After applying the paint P inside in one cycle, spray gun 1
2 is attached to the mounting table, the limit switch 14 attached to the mounting table is activated so that the amount (23 mA) of paint P to be applied to the next substrate is supplied into the cup 12a. It has become.

Next, a method of forming a film on the surface of a base material using the coating apparatus configured as described above will be described.

First, the spray gun 12 with the empty cup 12a is mounted on the mounting table, and in this state, when the coating device is operated and the shutoff valve 5 is opened, compressed air at a constant pressure is supplied from the pressure source 2 into the paint tank l. Then, the paint P in the paint tank 1 is stirred. Then, as a measuring step of measuring an amount of paint P that can form a film of a predetermined thickness from this paint tank 1, a discharge pump 6 is discharged from the pressure source 2 via a direction switching valve 7.
Compressed air is supplied to the paint tank 1, and by returning the piston 9 of the discharge pump 6 with the compressed air, the paint tank 1
A certain amount (23 rrl in this case) of paint P is measured and sucked into the cylinder 8 of the discharge pump 6 from inside.

Then, as a supply step for supplying the measured paint P into the cup 1.2a of the spray gun 12, the piston 9 of the discharge pump 6 is operated to discharge the paint P in the cylinder 8 and into the cassob 12a. supply to Therefore,
In this embodiment, the discharge pump 6 serves both the metering process and the supply process.

Note that compressed air is supplied to this spray gun 12 via a second branch path 11.

When the paint P is supplied into the cup 12a of the spray gun 12 in the paint supply process as described above, the operator removes the spray gun 12 from the mounting table and operates the switch 12b to coat the surface of the base material. A coating step is started in which the atomized paint is evenly sprayed to form a predetermined film thickness on the surface of the base material. In this coating process, in one cycle, Kanobu 12a
Continue repeating the coating operation multiple times until the paint P inside is completely gone. When the sprayed paint dries, a film having a predetermined thickness meeting the standard value of 20 μm is formed on the surface of the base material, and the intended pad is obtained.

When all the paint P in the cassette 12a has been applied in the coating process, the 1 cycle ends, and the spray gun 12 is turned on! !
When installed on the mounting table, the same installation status will be displayed.
4, and based on the 1 negative output signal, the metering process and the supply process of the next cycle are started, the discharge pump 6 is operated, and a predetermined amount of paint P for coating the next base material is measured, It is supplied into the cassop 12a of the spray gun 12.

As described above, according to the coating method of this embodiment, the amount of paint P necessary to obtain a coating on one pad is measured and sprayed using the discharge pump 6, which performs the metering process and the supply process at the same time. The cassop 12a of the gun 12 is supplied by the operator.
Since the coating work is performed many times until =t=rp in a is used up and these are treated as one cycle, there is no need to count the number of times of application, unlike the conventional number of times management system. Therefore, it is possible to reliably form a film having a predetermined thickness that satisfies the standard value without causing any miscount by the operator or due to variations in the discharge amount.

Note that the present invention is not limited to the configuration of the above-mentioned embodiments, and may be applied to resin molded products other than steering wheel pads, such as coating of automobile bumpers, etc., without departing from the spirit of the invention. It can also be changed and made more concrete.

[Effects of the Invention] As detailed above, the coating method of the present invention eliminates the need for operators to manage the number of coatings, and prevents variations in film thickness due to miscounting of the number of coatings or variations in the amount of spraying. This provides an excellent effect in that a predetermined film j7 can be reliably formed on the base material.

[Brief explanation of drawings]

The figure is a circuit diagram of a coating device showing an embodiment of the present invention. ■...Paint tank, 6...Discharge pump, 12...
Spray gun, 12a...Cup as a reservoir, P
···paint.

Claims (1)

[Claims] 1. Supplying the paint (P) stored in the paint tank (1) to the spray gun (12);
In a coating method in which paint (P) is sprayed multiple times onto the base material of a resin molded product to form a film by manipulating the ) from the paint tank (1), a supply step of supplying the measured paint (P) to the reservoir (12a) of the spray gun (12) by the discharge pump (6), and the reservoir. (12a) A method for coating a resin molded article, comprising a coating step of completely coating the supplied paint (P) and forming a film of a predetermined thickness on the base material in one cycle.