JPH0342947B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of coating the bottom side of bottles.

[Conventional technology]

Bottles such as glass bottles have extremely high mechanical strength when intact, but if their surfaces are scratched, they may deteriorate when subjected to strong internal pressure or various external pressures. They also tend to be easily damaged due to scratches.

The parts that are most susceptible to damage in these bottles are the bottom and bottom side of the body, which come into contact with other objects during transportation, especially around the bottom corners from the bottom to the bottom side of the body.The strength of this bottom side is increased. In order to achieve this, a technique has been proposed in which a coating agent is applied to the bottom side of the bottles.

For example, Japanese Patent Publication No. 52-26531 discloses that while the bottle is held horizontally and rotated around the center axis, a paint is allowed to flow down near the bottom of the bottle, and a gas is sprayed towards the paint. A technique has been disclosed in which the paint is applied to the bottom of the bottle by blowing it onto the center of the bottom of the bottle.

Since this method does not allow the paint to adhere to the lower side of the bottle body or the bottom corner, which is most susceptible to damage, the paint is poured from the nozzle onto the bottle while rotating it in a horizontal position. A technique has also been disclosed in which the coating is applied by blowing gas and smoothed by blowing gas.

[Problem to be solved by the invention]

However, the above method requires two sets of coating devices to reinforce the bottom side of the bottle, and also requires difficult setting of conditions such as nozzle position, gas blowing pressure, paint supply amount, etc., and complicated control. It was hot.

In addition, if the nozzle position or gas blowing pressure is incorrectly set, there is a risk that the paint supplied near the bottom of the bottle may pass through the gas spray layer, resulting in insufficient supply of paint. There were problems in that the thickness of the resin coating became thinner and the finish of the coating tended to be uneven.

Furthermore, there is a concern that the paint may scatter due to the gas spraying and adhere to surfaces other than the bottom of the bottle.
There were problems that not only looked bad, but also led to the production of defective products.

An object of the present invention is to provide a coating method that can form a coated surface with a uniform film thickness and a beautiful finish on the bottom side of a bottle by extremely simple control without any of the problems associated with conventional methods. It is said that

[Means to solve the problem]

The method of painting the bottom side of bottles according to the present invention, which achieves the above object, involves rotating the bottle, which is held with the bottom surface inclined upward, around the central axis, and painting the bottom side of the bottle in an area extending from the bottom surface to the lower side of the body. The system is characterized in that after the coating agent is supplied in a flowing manner, the bottles are held horizontally and rotated.

[Effect]

According to the above method, the paint is supplied in a flowing manner from the bottom of the bottle held in an inclined state to the lower side of the body, and then the bottle is held in a horizontal state and rotated, so that the paint is spread and smoothed on the bottom of the bottle and the lower side of the body.

On the other hand, the parting line between the coating agent supplied to the lower side surface of the body and the non-coated surface becomes almost a straight line because the bottle is kept in a horizontal state.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

Fig. 1 shows the main part (resin coating part) of a resin coater device to which the present invention is applied, and 10 is a conveying device that runs longitudinally through the resin coating part, and is moved in a direction perpendicular to the plane of the paper by means of a sprocket wheel (not shown). Endless conveyance chain 11,1 conveyed to
1', its conveyance guides 12, 12', and bases 13, 1
It consists of 3'.

One conveyor chain 11 is provided with a plurality of fixing blocks 14 at appropriate intervals in its length direction via mounting fittings 15 and 16.

Reference numeral 21 denotes a movable block which is pivotally supported to the fixed block 14 so as to be rotatable around a pivot shaft 22. A shaft 23 has the movable block 21 as a bearing, and a roller 24 and a washer 25 are provided around the shaft to rotate as one. Reference numeral 26 denotes a screw spout holder that is screwed onto the shaft 23, and a threaded portion 26A for the screw spout 31 of the bottle 30 is screwed inside the holder. 27 is an endless belt driven in a direction perpendicular to the plane of the paper by a pulley (not shown), 28 is its guide, and 29 is a holding member that holds the guide 28. The roller 24 is configured to slide and rotate as the belt 27 advances.

The above 21, 23, 24, 25, 26 are bins 30
A holding and rotating mechanism (hereinafter referred to as a holding mechanism) X is formed to hold the bottle 30 and rotate the bottle 30 around its central axis 32.

40 is a nozzle provided above the bottom surface 33 of the bottle 30 for supplying the paint 41. When only one nozzle 40 is provided in the resin coating part, it is configured to be movable along the central axis direction of the bottle 30. Furthermore, when a plurality of nols 40 are provided, they are arranged so that the coating agent 41 is supplied from near the bottom corner of the bottle 30 to the center. In each case, the nozzle or nozzles are moved synchronously with the bin 30 along the transport direction of the bin 30.

51 is a spacer which, when the bottle 30 held by the holding mechanism X passes near directly below the nozzle 40,
The central axis 32 of the bottle 30 is at a predetermined angle (α
The holding member 29 is interposed between the holding member 29 and the frame 60 so as to be inclined upward by an angle of 1°. In order to tilt the bottom surface 33 of the bottle 30 upward as described above, as shown by the dashed line, a rod-shaped supporter 52 made of, for example, soft resin or rubber is used to tilt the bottom surface 33 of the bottle 30 close to the bottom surface 33 of the bottle 30. The bottle body may be held by lifting the vicinity of the lower end thereof.

The above-mentioned inclination angle α is suitably 5° to 45°, more preferably 5° to 15°. This is the bottom 3 below 5 degrees.
This is because it becomes difficult to sufficiently coat the center part of the bottle 3 with the paint 41, and if the angle exceeds 45 degrees, the paint 41 coated on the bottom surface 33 will flow down toward the bottle mouth along the sides.

Further, the distance L between the nozzle 40 and the bottom surface 33 of the bottle 30 is set to be small, for example, about 20 mm, since it becomes difficult to supply the coating agent 41 to a predetermined position if it becomes large.

If the diameter of Norz 40 is too small, it will cause clogging, and if it is too large or too small, it will be difficult to apply a coating with a uniform thickness, so it is set to about 0.5 to 5 mmΦ. Ru.

On the other hand, the coating agent 4 supplied downstream from the nozzle 40
Examples of 1 include polypropylene, polyethylene, polyester, polycarbonate, polystyrene,
PVC, polyurethane, epoxy, and acrylic resins are used, and their viscosity should be 100 to 8000 CPS (at 25°C) in order to prevent dripping and form a film with a uniform thickness. .

Next, the operation of the method of the present invention will be explained. The bottle 30 is placed in the holding mechanism X after undergoing processes such as cleaning and pretreatment.
It enters the resin coating part in a state where it is held in place.

As the belt 27 is fed, the roller 24 slides and rotates, thereby rotating the shaft 23, so that the bin 30 rotates around its central axis 32. The rotational speed at this time is determined in consideration of the viscosity of the coating agent 41 and the amount of discharge from the nozzle 40, and is usually 1 to 30 rpm.

The bottle 30, which has reached almost directly below the nozzle 40, rotates as described above, and the paint 4 from the nozzle 40 is removed.
Receives a downstream supply of 1. For example, one nozzle 4
0, the nozzle 40 is moved in the direction of the central axis of the bottle 30, and the coating agent 41 is spirally supplied in a range extending from the bottom surface 33 of the bottle to the lower side of the body, including the bottom corner. .

The bottle 30 that has received the paint 41 is returned to a horizontal state and rotated to smooth the paint 41 on the bottom surface.

Bottle 3 supplied with paint 41 in this way
0 is appropriate rotation at the next curing section (e.g.
10 to 20 rpm) and is heated by a heater (eg, 100 to 200°C for 5 to 20 minutes) to undergo baking.

Note that curing and baking may be performed immediately after the coating agent 41 is supplied in a downward direction.

The various conditions performed by the inventor were as follows. Bottle 30: 450g, 1, Bottle rotation speed when flowing: 30rpm Paint: Reaction curing urethane resin,
300CPS (at 30℃) Number of nozzles used: 20, Nozzle diameter 0.6mmΦ dimension L: 20mm, Flow rate: 2g/1 nozzle, Bottle rotation speed during baking: 15rpm, Baking temperature 150℃
Baking time: 10 minutes, heating device: ordinary infrared heater Under the above conditions, it was possible to form a coating of coating material 41 with a uniform thickness of 200 μm on the bottom surface 33 of the bottle 30 and the lower surface of the body.

Further, the coating agent 41 supplied to the lower side surface of the trunk
The parting line 34 with the non-painted surface is
By rotating the 0 while keeping it horizontal, it took on a nearly straight shape.

FIG. 2 is a schematic configuration diagram showing an example of a resin coater apparatus to which the method of the present invention is applied, and FIG. 3 is a sectional view taken along the line -- in FIG. 2.

As shown in the figure, the resin coater apparatus is provided with a conveying device 10 equipped with an endless conveying chain 11 that is conveyed from the lower stage to the upper stage and back again to the lower stage. A drive motor 18 is a deceleration and transmission mechanism.

A is a bottle attachment/detachment portion for attaching/detaching the bottle 30 to the screw opening holder 26 of the holding mechanism X described above. Reference numeral B designates a cleaning section that cleans the bottom 33 of the bottle 30 held by the holding mechanism X, and is equipped with a rotating brush 61. C is a bottom primer application section that pre-processes the cleaned bottom 33, and is equipped with a rotating brush 62. 63 is an exhaust duct for exhausting gas, steam, etc. generated during primer application.

D is a resin coating part, and the structure of this part is as shown in FIG. 1, 64 is a motor for driving the belt 27, and 65 is an exhaust duct.

E and F are first and second curing parts, both of which have substantially the same configuration. That is, 66 is a heater, and 67 and 68 are belts and motors for rotating the bin 30. The curing rings E and F may be provided at one location.

The bottle 30 whose bottom surface 33 is painted is A,
After successively passing through parts B, C, D, E, and F, it returns to part A and is removed from the holding mechanism X.

Note that in the above explanation, the bottom surface of the bottle is inclined so as to face diagonally upward, and the paint is supplied from above. However, the present invention is not limited to this, and the bottom surface of the bottle is It is sufficient that the coating material is at an angle with respect to the supplied coating material, and therefore, the coating material may be supplied from below or from the side.

As explained above, the method of painting the bottom side of bottles according to the present invention involves supplying the coating agent downward to the bottom side of the rotating bottles in an inclined position, and then
It is characterized by the fact that the bottles can be switched to a horizontal position, and this allows uniform thickness to be applied from the bottom of the bottle, including the bottom corners, to the lower side of the body, without scattering or insufficient supply of paint. With this coating, it can be reinforced all at once, and the parting line has a beautiful straight line finish.
The device itself and the control system have been significantly simplified compared to the conventional method, and as a result, costs have been reduced.

[Brief explanation of drawings]

Fig. 1 is a front view showing the main parts of a resin coater device to which the coating method of the present invention is applied, Fig. 2 is a side view showing the schematic configuration of the resin coater device, and Fig. 3 is a cross-sectional view taken along the line - - in Fig. 2. It is. 30... Bottles, 32... Central axis line, 33...
Bottom surface, 40...nozzle, 41...painting agent.

Claims (1)

[Claims] 1. While rotating bottles held with their bottoms tilted upwards, paint is supplied in a downward direction from the bottom to the side of the body, and then while holding the bottles horizontally. A method of painting the bottom side of bottles, characterized by rotating the bottom side of the bottles.