JPH04154571A - Stretchable air bag cushioning material sheet equipped with self seal type blow-in tube and its manufacture - Google Patents

Abstract

PURPOSE:To prevent a blow-in tube from bending in an expanded air bag by a method wherein a blow-in tube on which slits to become self-seal valves are formed is placed with its one side edge between longitudinal edges of continuously long bag films overlapped, top and bottom, which constitute individual air bags, and integrally heat-sealed. CONSTITUTION:A film for tube 1 is longitudinally double-folded with its non- weldable processing part 3 on the inside, and a flat cylindrical shaped blow-in- tube 5 is formed by heat-welding overlapped side edges 4, 4'. Thus formed self seal type blow-in tube 5 is bound together with the longitudinal edge of an air bag at the time of forming of the air bag. In order to form the air bag, two sheets films for bag 11, 12 are prepared. The films 11, 12 are overlapped, and both longitudinal edges are arranged to be even. The welding side edges 4, 4' of the formed blow-in tube 5 are placed between one side longitudinal edges of the films 11, 12 and are heat-sealed together to form a longitudinal heat-seal line 13. A longitudinal heat-seal line 13' is formed on the other longitudinal edges in the same manner to close the other longitudinal edges.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION The present invention relates to an inflatable airbag cushioning sheet with a self-sealing blow tube and method of manufacturing the same. In particular, the present invention provides an inflatable airbag cushioning sheet with a self-sealing blowing tube in which the blowing tube is fixed by longitudinal heat-seal lines on the side edges of the airbag and does not float, and a method for manufacturing the same. This relates to the method of

[Background of the invention]

The present inventor has developed many inflatable self-sealing cushioning sheets. One of them is Utsukai Showa 62-
No. 93066 discloses a ``variable expansion self-sealing cushioning material.'' When air is blown into the cushioning material, the cushioning material, which was originally a flat sheet, expands to the required thickness at the desired location, and the swollen portions expand individually. The idea is to form a self-sealing valve. This cushioning material has a smaller volume before use compared to previously known air-filled cushioning materials (for example, the cushioning sheet known as Air Cap), and the individual parts that expand It is superior in that it can inflate independently and variably depending on conditions such as force, etc., which is unprecedented in the past. However, this cushioning material can be used in a relatively large amount (
There were problems such as requiring materials over a large area, the structure was complex, and the manufacturing process was not practical.

Therefore, the inventors of the present invention attempted various improvements and developed a more practical expandable self-sealing cushioning sheet as disclosed in Utility Application No. 1-120288. The "expandable self-sealing cushioning material sheet" disclosed in Utility Application No. 1-120288 is made by heat-sealing two upper and lower belt-shaped films at both vertical edges to form a flat cylindrical body. Pass the air blowing tube formed with a slit valve through the
A cushioning material sheet in which a large number of individual airbags are connected is formed by heat-sealing the band-shaped film crosswise at a position that does not overlap with the slit valve.

By the way, the above-mentioned air blowing tube is a flat tube made by heat-sealing two strip films narrower than the strip film at the vertical edges on both sides, and the air-blowing tube is made of a flat tube that connects the large number of airbags at the ends in the length direction. It penetrates from the end to the end,
For each airbag, the outer surface of the blow tube is only fused at the transverse heat seal, and is left loose inside the individual airbag.

Therefore, when an individual airbag is inflated, the airbag and insufflation tube, which had the same length in the vertical direction when they were originally in a flat state, become longer by the length of the insufflation tube as the airbag inflates and becomes round. A problem has been identified in that the insufflation tube must be present in a tortuous or twisted configuration within the airbag.

The bending of the blow tube not only gives rise to an unsightly appearance but also impairs the self-sealing action of the blow tube.

Furthermore, constructing the blow tube in the utility model registration application from two strips of film does not itself require a very difficult process, but from a practical point of view, it is a simpler and more efficient blow tube. It was hoped that the manufacturing method would be realized.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the problem in conventional self-sealing cushioning materials in which the blow tube bends inside an inflated airbag and the associated problems.

Specifically, the present invention provides an inflatable airbag cushioning sheet with a self-sealing blow tube such that the blow tube behaves integrally with the individual air bag before and after inflation. The purpose is to provide

A further object of the present invention is to provide a method for easily and quickly manufacturing an inflatable airbag cushioning sheet having a self-sealing blow tube as described above.

[Means to solve the problem]

Therefore, in the present invention, a blowing tube having a slit serving as a self-sealing valve is sandwiched between one side edge of the blowing tube and the overlapping vertical edges of a continuous length of bag film constituting each airbag. The airbag and the blow tube are integrated by heat sealing.

The blow tube according to the present invention is formed by vertically folding one double-width tube film into two, instead of using two upper and lower films. A slit is formed in the vertical line that is folded in half to form a matching slit, which serves as an inlet for air from the blow tube into the airbag, and when the top and bottom surfaces of the blow tube are in close contact with each other, a self-seal valve or slit valve is formed. Let it be.

Approximately half of the width of the tube film constituting the blown tube, excluding the side edges to be fused, is coated with a thin film of non-thermal adhesive material such as a silicone-based heat-resistant release agent. , which facilitates the formation of the blow tube.

The blow tube with slits is folded in half and its edges are fused to form a flat cylinder.The fused side edges are sandwiched between the stacked vertical edges of the upper and lower two layers of bag film. At the same time as the vertical heat seal is formed, it is heat sealed and integrated into the bag film. In this way, the blowing tube of the present invention is always fixed to the vertical heat-sealing line of the airbag, whether it is in the fan state before air is blown into it or in the inflated state after air is blown into it. It does not float or twist inside the airbag, and can stably exhibit its self-sealing effect.

[Example] An example of the present invention will be described with reference to the drawings. First, FIGS. 1 and 2 illustrate the manufacture of the self-sealing blow tube of the present invention.

The tube film 1 has a predetermined continuous length twice the width of the blow tube 5 (FIG. 2) to be formed.
Heat-sealable, non-breathable, flexible 1 Mechanically strong material, preferably a laminate of nylon and polyethylene.
Prepared from film etc. Center of width of film 1,
In other words, slits 2 are formed at predetermined intervals along the vertical center line.
are formed in large numbers. The predetermined interval is an interval approximately corresponding to the length of one of the individual airbags to be formed (lO□, 10□, etc. in Fig. 3).6 On one side of the vertical centerline, A non-fusion treated portion 3 is formed with a narrow width left on the side edge 4. Non-bonding treatments may be applied by coating or other means with silicone-based heat-resistant releases, heat-resistant printing inks, or non-heat-bonding liquids such as solutions of inorganic powders such as talc or clay. It is done.

The tube film l is vertically folded in half with the second non-fusion treated part 3 as the inner surface, and the overlapping side edges 4 and 4' are heat fused to make it flat. A cylindrical blowing tube 5 is formed. That is, the blowing tube 5 has two surfaces 1, an upper surface 5u and a lower surface 5Q, in a flat state. Slits 2 are formed at appropriate intervals on the boundary between the top and bottom surfaces, and the slits 2 cooperate with the flat top and bottom surfaces to form a self-sealing valve (or slit valve).

The self-sealing blow tube 5 thus formed is then sewn together with its longitudinal edges (edges along its length) during the formation of the air bag.

For airbag formation, as shown in FIG.

Two bag films 11, 12 are prepared. This film is also prepared from a heat-sealable, breathable, flexible, mechanically strong thin film material, preferably a nylon and polyethylene laminate film or sheet.

The films 11 and 12 are stacked, their longitudinal edges aligned, and the fused side edges 4 and 4' of the blown tube 5 formed as described above are sandwiched between one longitudinal line and heat sealed together. llA13 is formed. Similarly, a vertical heat seal line 13' is formed on the other vertical edge and closed. The end of the blowing tube 5 is an open end 6, which protrudes from the end of the bag film 11.degree. 12 by a distance N, as shown in FIG.

Finally, horizontal heat seal lines 14 are formed transversely at predetermined intervals to form a plurality of independent inflatable airbags 10□, 10□, 10. , IO4... to obtain the cushioning material sheet of the present invention. Adjacent horizontal heat seal lines! 4
．． Between the airbags 14, airbags 15 are formed with appropriate dimensions.In practice, it is desirable for manufacturing to have 10 to 20 individual airbags 10 connected in series. If not all the airbags are required for use, the required number of airbags 10 may be used by cutting them at the connecting portions 15 as appropriate.

This cutting can be done before or after blowing air into the single piece of cushioning material. The outer end of the cushioning material sheet is an open end 16 since it is not necessary to close it.

In addition, instead of using two pieces of bag film 11 and 12, one double-width bag film is folded lengthwise in half and a blowing tube is placed between the two overlapping vertical edges in the same manner as shown in Section 3. The vertical heat seal 13 may be formed by sandwiching them. In this case, of course, the other vertical heat seal 13' is not necessary.

According to the invention, the slit-valved blow tube 5 passes through the individual airbags and the lateral heat seal line 14
and the vertical heat seal line 13 to fix the airbag to the airbag. The inner surface of the bag film 11.12 and the outer surface of the blow tube 5 are fused together at the lateral heat seal line 14, but the inner surface of the blow tube 5 is
Since the non-fusion treatment 3 is applied, a blowing air passage is left that communicates between each air bag without causing any fusion.

In this connection, the non-fusion treated part 3, which is conveniently shown as countless small dots in Fig. 1, does not necessarily have to be formed on the entire surface of one side of the vertical center line, and is equivalent to the horizontal heat seal shown by the thick chain line. It may be partially formed only in the area including line 7, but
In this case, care must be taken so that the welding of both side edges 4.4' does not exceed a predetermined narrow width.

Furthermore, the slit 2 is the horizontal heat seal equivalent line 7 in Fig. 1.
Although each airbag is shown as having three grooves in the middle, a total of two or more may be formed for each airbag, one closer to the lateral heat-sealing equivalent line.

Also, the side edges 4, 4' of the blow tube 5 are shown in FIG.
When forming the vertical heat-sealed line 13 in combination with 1.12, it is also possible to simultaneously fuse the inner surfaces of the side edges 4, 4'.

Next, the function of the cushioning material sheet of the present invention will be explained with reference to FIGS. 4 to 6. FIG. 4 is an end view of the cut portion corresponding to the line ``--'' in FIG. 3, and shows a flat state in which air has not yet been blown. In the figure, the upper surface 5u and lower surface 5Q of the blow tube 5 are drawn a little apart to show the slit 2, and the bag films 11 and 12 of the airbag 10 are drawn far apart to make the blow tube itself clear. In reality, the entire structure is a flat layered body that is closely connected and can be represented by a single straight line.

When a device such as a nozzle from a near compressor (not shown) is inserted into the open end 6 (FIG. 3) of the blow tube 5 and air is injected, the upper surface of the blow tube 5 as shown in FIG. 5u and the lower surface 5k are inflated, the slit 2 is expanded, air A is allowed to flow into the airbag 10, and the airbag 5k is inflated. The blowing tube 5 connects each airbag 10□
, IO□..., the airbags are inflated simultaneously or at least sequentially by blowing from the open end 6, and the inflation stops when the blowing pressure and the airbag internal pressure are balanced.

When the blowing is stopped, the upper and lower surfaces 5u and 5Q of the blowing tube 5 are flattened by the pressure a filled in the airbag, and the slit 2 is closed, forming a self-sealing valve, as shown in FIG. do.

In Figure 6, the collapsed insufflation tube 5 is shown horizontally; however, depending on the situation, the insufflation tube 5 may become flattened by being biased or pressed to either the upper or lower side of the airbag. .

[Effects of the Invention] As is clear from the above, by binding and fixing the blow tube to the vertical heat seal line of the air bag according to the present invention, the blow tube does not move or float inside the air bag during air blowing. The air flow is smooth and the blowing operation is carried out quickly, and the blowing tube is housed in a fixed position on one side of the inflated airbag after the blowing is completed, making it possible to move the air more smoothly than before. This has the advantage of ensuring the self-sealing action of the blow tube without exposing the crooked shape in the middle of the airbag, which makes it look bad, or causing the slit valve to open involuntarily.

Furthermore, according to the present invention, the blown tube is formed by vertically folding a single tube film in half, which has been treated with non-adhesive properties at about half its width, and heat-sealing the side edges. Compared to the conventional method of overlapping two films and heat-sealing the edges on both sides, it has the advantage of being simpler to manufacture and ensuring a more reliable finish.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view illustrating one step of manufacturing a blow tube for a cushioning material sheet according to the present invention, FIG. 2 is a partial perspective view illustrating the next step of manufacturing the blow tube, and FIG. FIG. 4 is a partial perspective view showing a part of the airbag cushioning material sheet according to the present invention, in which one side edge of the blow tube is bound together with one side of the airbag by vertical heat sealing, FIG. 4 is a line IV-rV in FIG. FIG. 5 is an end view of the cut portion corresponding to the same portion as FIG. 4, showing the cushioning material sheet of the present invention in a flat state; FIG. FIG. 4 is an end view of a cut portion at the same portion as FIG. 4, illustrating a state after stopping. main! Number 1...Tube film L...Vertical center line 2
...Slit 3...Non-fusion treated portion 4.4'...Side edge to be fused 5...Blow tube 5u...-Upper surface 5Q...Lower surface 6... - Opening end 10 (10 10., 10....)...Individual airbags 11, 12...Bag film 13...Vertical heat seal line 14...Horizontal heat seal line

Claims (1)

[Claims] 1. The film for a thin tube has slits formed at predetermined intervals in the length direction almost along the longitudinal center line, and a side edge is left on one side of the longitudinal center line. A blow tube, which has a fusible treated portion and is folded in half along the longitudinal centerline and whose side edges are fused to each other, constitutes a number of individual airbags at the fused side edges. An inflatable airbag cushioning material sheet equipped with a self-sealing blow tube, characterized in that it is sandwiched between the overlapping longitudinal edges of a bag film and fixed together by a longitudinal heat-sealing line. 2. The cushioning material sheet according to claim 1, wherein said blow tube has two or more said slits in each air bag. 3. The cushioning material sheet according to claim 1, wherein the bag film comprises a single film having a width approximately twice as wide as the width of the airbag to be constructed. 4. Prepare a long and thin sheet of heat-sealable tube film, form a large number of slits at predetermined intervals in the length direction almost along the longitudinal center line of the tube film, and form a number of slits at predetermined intervals along the longitudinal center line of the tube film. On one side, leaving the side edges, non-fusible treatment by applying a non-fusible material selected from silicone-based heat resistant release agents, heat resistant printing inks or inorganic powders such as talc or clay. Fold the tube film in half along the vertical center line with the non-fusion treated portion as the inner surface, and fuse and close the combined side edges to form a flat cylindrical blown tube. between the overlapping longitudinal edges of a continuous length of heat-sealable bag film that constitutes a number of individual airbags.
The bag film and the blow tube are integrated by forming vertical heat seal lines across the fused side edges of the blow tube, and a number of horizontal heat seal lines are formed on the bag film at positions that do not overlap with the slits. A method of manufacturing an inflatable airbag cushioning sheet with a self-sealing blow tube, comprising: 5. For the bag film, prepare two films of the same width, overlap the vertical edges on both sides and close them with a vertical heat-sealing line, and one of the vertical heat-sealing lines fixes the blowing tube. 5. The method according to claim 4. 6. For the bag film, prepare a sheet of film that is twice the width of the airbag to be formed, fold it in half lengthwise, and sandwich the side edge of the blow tube between the overlapping vertical edges. 5. The method of claim 4, further comprising forming longitudinal heat seal lines.