JPS5850580B2 - Manufacturing method of rope-shaped cushioning material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mesh cushioning material for protecting objects that are easily damaged, such as fruits, fruit vegetables, glass products, and precision mechanical parts.

Traditionally, the manufacturing method for mesh cushioning material was
A method of assembling a set of dies, each with a plurality of extrusion grooves dug on opposing surfaces, in contact with each other based on No. 4185, and extruding foamed resin from the extrusion grooves while sliding the dies. be.

However, in the case of this method, only an ordinary net-like cushioning material with high extensibility in the lateral direction, in which the strands simply intersect, can be manufactured.

On the other hand, the present inventors have found that by having a transverse band, there is almost no lateral extensibility, and it is composed of a small number of strand parts and an overwhelmingly large number of diagonal parts (parts where strands overlap). We have invented a method for manufacturing mesh cushioning materials.

That is, in a method of manufacturing a net-like cushioning material by extruding foamed resin from the extrusion grooves while sliding a set of dies whose surfaces have a plurality of extrusion grooves in contact with each other, the extrusion grooves are This is a method for manufacturing a net-like cushioning material, characterized in that a set of dies are used in which all the holes are periodically staggered.

The manufacturing method of the present invention will be explained below based on the illustrated embodiments.

FIG. 1 shows a longitudinal cross-sectional view of the apparatus used in the invention when circular dies are used.

The outer die 1 is rotated by a clutch 3 rotated by a drive device 4 via a clutch pawl 5, and the inner die 2 is slid and rotated within the outer die 1 by a drive device 6 in the opposite direction to the outer die 1.

Extrusion grooves 7 are provided on each sliding surface of the outer die 1 and the inner die 2.
, 8 are dug, respectively, and a resin reservoir A is provided at the back of the extrusion grooves 7 and 8, which communicates with the extruder 10 via a flow path B in the fixed tube 16.

FIG. 2 is a front sectional view of the circular die, showing how the extrusion groove is dug.

A plurality of extrusion grooves 7 are dug on the inner surface of the outer die 1, and a plurality of extrusion grooves 8 are dug on the outer surface of the inner die 2 with a semicircular cross section, and the extrusion grooves of the outer die and the inner die are staggered. All holes are connected.

The foamed resin extruded from the extruder 10 passes through the channel B, is supplied to the reservoir A, and is extruded from the extrusion grooves 7 and 8, but the outer die 1 and the inner die 2 are rotating in opposite directions. By periodically connecting all the extruded grooves in a staggered pattern, a net-like cushioning material in which transverse bands appear periodically and is composed of a small number of strand portions and an overwhelmingly large number of diagonal portions can be obtained.

A conceptual plan view of the obtained mesh cushioning material is shown in Fig. 3.
FIG. 4 shows a YY cross-sectional view in the figure.

In both figures, the strand 7a extruded from the extrusion groove 7 and the strand 8a extruded from the extrusion groove 8 intersect diagonally and are integrated, and a mesh is formed by this diagonal intersection and the strands. There is.

A transverse band E having a width H appears periodically between diagonally adjacent meshes, and the action of the transverse band E creates a net-like cushioning material with almost no extensibility in the lateral direction.

Although the case of circular dies that slide and rotate in opposite directions has been described above, the case of flat dies is shown in FIG. 5 as another embodiment.

An extrusion groove 11 is dug in the upper die 1a, and an extrusion groove 12 with a semicircular cross section is dug in the lower die 2a.
The extrusion grooves 11 and 12 are all connected in a staggered manner.

In this state, by reciprocating the upper die 1a as shown by the arrow, a net-like cushioning material as shown in FIG. 6 is obtained.

In FIG. 6, the strand 1 extruded from the extrusion groove 12
2a extends straight in the extrusion direction, and the strand 11a extruded from the extrusion groove 11 reciprocates obliquely over the strand 12a and is fused and integrated with the strand 12a, and the mesh 9a is formed by this oblique part and the strand. has been done.

Also, as in the case of FIG. 3, transverse bands Ea having a width Ha appear periodically between the meshes in the vertical direction.

In the case of rotating dies, only either the inner or outer die may be rotated, or both or only one of the inner and outer dies may be oscillated.

Furthermore, in the case of flat dies, both the upper and lower dies may be slid (reciprocating motion), and it goes without saying that the stroke of the reciprocating motion can be freely selected.

Although the case where the extrusion groove has a semicircular cross section has been described above, the cross-sectional shape of the extrusion groove may be any shape such as a rectangle (see FIG. 7) or a triangle.

The inner surface of the extrusion groove may be a flat surface or an uneven surface, and regardless of the shape of the inner surface, the unit opening through which the resin is extruded is essentially the extrusion groove. to be called.

Next, the conditions under which the extrusion grooves are all continuous in a staggered manner will be explained with reference to FIG.

The width of the extrusion groove 13 is tl, the width of the extrusion groove 14 is t4, the interval between the extrusion grooves 13, 13 is t2, the interval between the extrusion grooves 14, 14 is t.
3, it is possible to make the extrusion grooves in a staggered shape communicate with each other at the ends 15 by simultaneously satisfying the following formula.

tl>t3 t4>t2 As long as these conditions are satisfied, the relationship between width t1 and width t4 and interval t2 and interval t3 may be the same or different.

Next, the formation state of the transverse band and the diagonal state of each strand in the present invention will be explained in more detail with examples to clarify the significance of the present invention.

Example 1 Foamed polyethylene was extruded using a rotating die under the following conditions.

(a) Die rotation speed: 20 times/min for both inner and outer dies (0
) Die rotation direction Inner and outer dies Reverse rotation (c) Die shape Inner diameter of sliding part 100TrrInφ Number of extrusion grooves 70 (both inner and outer dies) Extrusion groove cross-sectional shape Rectangular (both inner and outer dies) (3, 3 groups) t1=t4=3 .3 cylinder 11=14>122t3 L2=t3f: 1.19mm A partially enlarged plan view of the extruded mesh cushioning material is shown in FIG.

In FIG. 8, the tongue portions 18a of the diagonal portions 18 and the strand portions 17 are alternately fused and lined up in the lateral direction of the net-like tube material between diagonally adjacent meshes 9, and a cross section having a width H1 is formed. Band E is formed.

This transverse band E1 is formed when the extrusion grooves are all continuous in a staggered manner.

Example 2 In Example 1, the number of rotations of the dice was set to 2.4 times/min (both the inner and outer dice).

FIG. 9 shows a partially enlarged plan view of the extruded mesh cushioning material.

In FIG. 9, the configuration of the diagonal portion 21 and the transverse band Eal is the same as in Example 1, but because the die rotation is slow, the width Ha1 of the transverse band E a 1 is widened, and the presence of the transverse band is The presence of the long diagonal portion 21 is more obvious.

The oblique portion 21 has a shape similar to a single thick strand rather than an oblique strand.

Furthermore, the mesh 9 is composed of overwhelmingly long diagonal portions 21 and extremely short strand portions 22, and the difference from the mesh structure of the conventional mesh cushioning material is more obvious than in the first embodiment.

Although the two embodiments have been shown above, various forms of net-like cushioning materials can be obtained by changing the manufacturing conditions such as the shape of the extrusion groove and the number of revolutions.

For example, if the width of the extrusion groove is widened and the continuous hole portion is enlarged, a net-like cushioning material resembling a sheet with a small mesh can be obtained, but in any case, this is a modification of the net-like cushioning material obtained by the method of the present invention. There is no doubt that there is.

As can be understood from the above description, the present invention uses a set of dies in which all the extrusion grooves are periodically staggered, so that a net-like cushioning material having the following structural features can be obtained.

(B) It has a transverse section. (D) The diagonal part is longer than the strand part, and the main component of the net is the diagonal part.

Since the net-like cushioning material has these characteristics, it has various uses, and representative examples are shown below.

Generally, it is the diagonal part of the strand that exerts the buffering effect of a cushioning material, but the net-like cushioning material obtained by this method has the diagonal part as the main component (mostly the diagonal part), so it has special cushioning properties. In addition, since the transverse tension restricts the lateral extensibility, when used as a cushioning material, the mesh does not expand and the article does not come out, resulting in excellent functionality as a cushioning material.

If you slow down the die rotation, it will look like a "sudare" rather than a net shape.
Therefore, it can also be used as a packaging material with a cushioning material for packaging fruits and vegetables.

The net-like material obtained by simply extruding molten resin has almost no lateral extensibility due to the action of the transverse bands, so it can be used as a base material for soil improvement or as a net for ball game practice. obtain.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view showing the outline of the device, Figure 2 is a front sectional view of the circular die, Figures 3 and 6 are conceptual plan views of the mesh cushioning material, and Figure 4 is a diagram of Figure 3. YY cross section, FIG. 5 is an explanatory diagram in the case of a flat die, FIG. 7 is an explanatory diagram of the excavation state of an extrusion groove, and FIGS. 8 and 9 are partially enlarged plan views of the mesh cushioning material. 1... Outer die, 2... Inner die, 7, 8° 11.12, 13, 14... Extrusion groove, 7a, 8a. 11a, 12a, 19.20... Strand,
9゜9a...Mesh, 18.21...Oblique part, 17゜22...Strand part, symbol A.
...Resin pool, E. E a I E a 11 El...Transverse zone.

Claims (1)

[Claims] 1. In a method of manufacturing a mesh cushioning material by extruding a foamed resin from the extrusion grooves by sliding a set of dies whose surfaces have a plurality of extrusion grooves in contact with each other, the extrusion grooves 1. A method for manufacturing a net-like cushioning material, characterized in that a set of dies are used in which all the holes are periodically staggered.