JPS63130331A - Method of sticking label to blow molding made of synthetic resin - Google Patents

Abstract

PURPOSE:To obtain a bottle, to the outside circumferential surface of which a label is stuck, by a method wherein the label is fixed to a sucking surface of the label in a molding mold through suction before and air of about the same pressure as blow pressure is blown through a label suction hole after starting of blowing. CONSTITUTION:A label L to the inside of the inside of which a hot-melt adhesive agent has been applied beforehand is arranged on positions of suction surfaces 1a, 1a of the label of broken molding molds 1, 1 by an insertion device 9 of the label, air is sucked through label suction holes 5, 5 and the label L is fixed to the suction surface 1a, 1a of the label. Then after a parison 2 has been extruded by an extruding machine 3, both the molding molds 1, 1 are clamped, the upper end part of the parison 2 is cut off, a blow pin 4 is inserted through the upper part of the molding molds 1, 1 in place of he extruding machine 3, air is blown into the parison 2 and blow molding is started. When the parison 2 is swollen and the label L is pressed against the suction surface 1a, 1a of the label with blow pressure Pb, pressurizing air of the same pressure as the blow pressure Pb is fed through the label suction holes 5, 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for attaching labels to synthetic resin blow-molded products used as beverage bottles, containers for liquid detergent, and the like.

(Prior Art) Conventionally, as a method for manufacturing synthetic resin blow-molded products, a method described in Japanese Patent Application Laid-Open No. 61-246036 is known.

This conventional method is a method in which the inner surface of the mold and the flakes are made into a slightly uneven shape, and the flakes are bonded together by the heat of the parison during blow molding without creating a large number of air bubbles. .

Then, using a label instead of a thin piece in this conventional method,
When applying the method described in the example of the conventional publication,
As shown in FIGS. 7 and 8, one or several label suction holes 02, 02 are provided in the label suction surfaces 01a and Ola in the molding molds 01 and 01, and Until the blowing is completed, the label is molded into the mold 01. This is a method of suctioning and fixing the label to the label suction surfaces 01a and Ola in Of by vacuum action.

In addition, since the label L is thicker and wider than the thin piece, in order to obtain molded product B with the label L attached at the same time as blow molding, a high suction force is required to prevent the label from falling off. shall be.

(Problems to be Solved by the Invention) However, in such a conventional method, blow pressure (P b) acts from the inside at the position of the label suction hole 02 during blow molding, and the label suction occurs from the outside. Negative pressure (-Pr) acts, and a larger differential pressure ΔF (=P
b+Pr) occurs, which causes the following problems.

(2) As shown in FIG. 8, convex suction hole marks d are formed on the label surface of the molded product B due to the differential pressure ΔP, which impairs the product value.

■ If the wall thickness of molded product B is thin and the thickness of label L is also thin, there will be convex suction hole marks d that protrude greatly outward, which will not only look bad but also damage molded product B and label L. If a differential pressure ΔP that exceeds the durability limit is applied, a hole will be formed in the molded product B.

Note that the problems in (1) and (3) mentioned above are that after the start of blowing, suction by vacuum action is stopped, and the differential pressure Δ is mainly caused only by blowing pressure Pb.
The same applies to the case where P' is generated, as long as a large differential pressure ΔP' is generated.

(Means for Solving the Problems) The present invention is a method made for the purpose of solving the above-mentioned problems. In a method for labeling a synthetic resin blow-molded product, the label is attached to the outer circumferential surface of the molded product at the same time as the blow-molding process. Before starting blowing, the label is fixed to the label adsorption surface in the molding mold by vacuum action, and after starting blowing, the adhesion by vacuum action is stopped, and then air at approximately the same pressure as the blowing pressure is applied. It is characterized in that it is blown into the label adsorption hole.

(Function) In the method for attaching labels to synthetic resin blow-molded products of the present invention, as described above, after the start of blowing, adsorption by vacuum action is stopped, and then air at approximately the same pressure as the blowing pressure is applied to adsorb the label. Because we used a method of blowing through the holes, at the position of the label suction hole during blow molding, blow pressure acts from the inside, and air pressure that is almost the same as the blow pressure acts from the outside, and the pressure is offset by the two. As a result, almost no differential pressure occurs.

Therefore, convex adsorption hole marks are not formed on the label surface of the molded product, and furthermore, it is possible to mold a product with a thin molded product and a thin label.

(Example) EMBODIMENT OF THE INVENTION Hereinafter, an example method of the present invention will be explained in detail with reference to the drawings.

In describing the method of this example, a method of attaching a label to a shampoo bottle will be taken as an example.

First, a well-known blow molding apparatus is used in the method of the embodiment, and the blow molding apparatus includes a movable mold frame (not shown) to which a mold 1.1 is attached, a cylindrical mold made of synthetic resin (hereinafter referred to as a parison), ) 2, a blow pin 4 for blowing blow air into the parison 2, and the like.

An air pump 7 and a vacuum pump 8 are connected to the label suction holes 5.5 of the molding molds 1, 1 via a switching valve '6.

Note that the air pump 7 is a pump that produces pressurized air to the blowbin 4.

In addition, in the method of the embodiment, as a blow molding device, the molds 1 and 1 each have a mold formed by dividing the shape of a shampoo bottle B into two, and a label L is inserted into the mold 1.1. A label insertion tool 9 is used.

Incidentally, the label adsorption surface 1a in the molding die 1, 1.

A plurality of label suction holes 5° 5 are provided in each of the holes 5.

Next, the example method will be explained in order according to each step.

(a) Label suction step As shown in FIG. 1, the label suction surface 1a of the molding die 1.1 is opened by the label insertion tool 9.

Place label L at position la.

Then, by switching the switching valve 6 to the vacuum pump 8 side and sucking air from the label suction hole 5.5, the label L is attached to the label suction surfaces 1a, la of the molding molds 1, 1, as shown in FIG. Fixed.

Note that an adhesive that melts with heat is applied to the inner surface of the label L in advance.

(b) Parison extrusion process After the label L is suctioned and fixed in the label adsorption process mentioned above, while the label L is kept fixed, as shown in Fig. 3,
The extruder 3 extrudes the parison 2 into a cylindrical shape having a required length.

(c) Blow molding process After completing the above-mentioned parison extrusion process, the remolding molds 1, 1
The mold is clamped, and the upper end of the parison 2 is cut. At the same time, a blow pin 4 is inserted from the top of the molding die 1.1 instead of the extruder 3, and blow air is blown from the blow bin 4 as shown in FIG. , start blow molding.

Before the start of this blow molding, air is being sucked out from the label adsorption hole 5 by the vacuum pump 8, but the switching valve 6 is switched to the air pump 7 side almost at the same time as the start of the blow molding. .

Then, when the parison 2 expands and the label L begins to be pressed against the label suction surfaces 1a, la with the blow pressure Pb, pressurized air having the same pressure as the blow pressure Pb is supplied from the label suction hole 5.5.

Note that during this blow molding, the label L is firmly adhered by the heat from the parison 2.

Therefore, as shown in FIG. 5, at the positions of the label suction holes 5, 5 during blow molding, the blow pressure pb acts from the inside, and the air pressure Pa, which is the same as the blow pressure Pb, is also applied from the outside.
acts, and the pressure is canceled out by the two, resulting in almost a differential pressure ∆
No occurrence of P.

(d) Bottle molding completion step In the blow molding process described above, blow pressure Pb and air pressure Pa are applied for a predetermined period of time, and when the blow molded product is hardened to the extent that it can self-retain its shape, the remolding molds 1, 1 are released. As shown in FIG. 6, the molding of the shampoo bottle B with the label L attached to the outer circumferential surface is completed at the same time as the blow molding by removing unnecessary edges at the mouth and bottom.

As explained above, in the method of attaching the label to the shampoo bottle B of the embodiment, the following effects can be obtained.

■ After the blow starts, stop the suction by vacuum action, and then apply air at the same pressure as the blow pressure Pb to the label suction hole 5.
．． Because of the method of blowing from 5.5, there is no differential pressure ΔP generated at the position of the label suction hole 5.5 during blow molding, unlike in the past, and there is no pressure difference ΔP that is generated on the surface of the label L of the shampoo bottle B. No hole marks are formed.

■ As mentioned above, no convex suction hole marks are formed on the surface of the label L of the shampoo bottle B, and no holes are formed from the label suction holes 5.5 during blow molding. , it is possible to mold products with a thin molded product and a thin label.

(2) After the start of blow molding, the air pressure Pa equal to the blow pressure Pb is blown through the label suction hole, so that the convex suction hole traces can be made completely unnoticeable from the outside.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific method is not limited to these embodiments, and even if there is a change in the method without departing from the gist of the present invention, the present invention include.

For example, in the example, after the start of blow molding, the blow pressure Pb
We have shown an example in which air with the same pressure as Pb is blown from the label suction hole, but depending on the thickness of the molded product or label, even if a pressure slightly higher or lower than the blowing pressure Pb is blown, large convexities may occur. High or low pressure levels are permissible as long as no traces of adsorption pores are formed.

Further, in the examples, an example of shampoo bottle B was shown, but it goes without saying that the applicable blow-molded product is not limited to this shampoo bottle.

In addition, there is a time limit on when to stop label adsorption due to vacuum action, if the vacuum action is released all at once, there is a time limit such as after the parison swells and there is no longer any concern that the label will fall off due to the parison, but in general, it is gradually stopped. Since the vacuum effect decreases over time, it is sufficient to set the time somewhat after the start of blowing, that is, almost at the same time as the start of blowing.

In addition, regarding the timing of air blowing from the label suction holes, since the parison does not harden in a short time, it does not need to be carried out immediately after stopping the label suction described above, and even if there is a slight delay. Permissible.

(Effects of the Invention) As explained above, in the method for attaching labels to synthetic resin blow-molded products of the present invention, after the start of blowing, adsorption by vacuum action is stopped, and then the pressure is approximately equal to the blowing pressure. By blowing high pressure air through the label suction holes, no convex suction hole marks will be formed on the label surface of the molded product, and it can also be used for products with thin molded product walls and thin labels. The effect is that it can be molded.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a blow molding device used in the shampoo bottle labeling method according to the embodiment of the present invention;
The figure is an explanatory diagram of the label adsorption process in the example method, Figure 3 is an explanatory diagram of the parison extrusion process in the example method, Figure 4 is an explanatory diagram of the blow molding process in the example method, and Figure 5 is an explanatory diagram of the blow molding process in the example method. FIG. 4 is an enlarged view of part A, FIG. 6 is an explanatory diagram of the bottle forming completion process in the embodiment method, FIG. 7 is an explanatory diagram of the conventional blow molding method,
FIG. 8 is an enlarged view of part C in FIG. 7. 1...Molding mold 2...Parison 3...Extruder 4...Blow bin 5...Label adsorption hole 6...Switching valve 7...Air pump 8...Vacuum pump

Claims (1)

[Claims] 1) One or several label adsorption holes are provided on the label sticking surface in the mold, and the label is attached to the outer peripheral surface of the molded product at the same time as blow molding in the mold. In the method for attaching labels to synthetic resin blow-molded products, before the start of blowing, the label is adsorbed and fixed to the label adsorption surface in the molding mold by vacuum action, and after the start of blowing, the label is fixed by vacuum action. A method for attaching a label to a blow-molded product made of synthetic resin, the method comprising stopping adsorption and subsequently blowing air at approximately the same pressure as the blow pressure through the label adsorption hole.