JP2001206449A - Cushioning sheet and cushioning envelope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cushioning sheet which can be heat-welded to a chartaceous sheet at a low heating temperature and a cushioning envelope wherein the cushioning sheet is lined on the chartaceous sheet without an adhesive and a chartaceous part and a plastic part can be easily separated after use. SOLUTION: An undercover film 3 of a bubble sheet 1 to be lined on the cushioning envelope is formed of a straight-chain low density polyethylene with a low melting point, and the bubble sheet 1 is heat-welded to respective chartaceous sheets 13, 14 with a side of the undercover film 3 facing the chartaceous sheets 13, 14 on a surface and a rear. Thus, the undercover film 3 with a low melting point can interdigitate with unevenness on surfaces of the sheets 13, 14 with high flowability even at a low heating temperature. Therefore, the bubble sheet 1 can be fixed to the respective sheets 13,14 without an adhesive even on a side rim of an envelope opening 15 where the heating temperature cannot be set high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buffer sheet and a buffer envelope lined with the buffer sheet.

[0002]

2. Description of the Related Art As a buffer envelope for protecting easily breakable articles from impact, an envelope in which a buffer sheet is lined with a paper sheet is used. As this buffer sheet,
A so-called bubble sheet in which a large number of independent air-filled portions are formed between two or three stacked plastic films, a foamed plastic sheet in which air bubbles are generated, and the like are used.

As means for lining the cushioning sheet on the paper sheet, there are a method using an adhesive and a method using heat welding. When using an adhesive, it is necessary to precisely control the position and amount of the adhesive to be applied so that the adhesive does not protrude from the bonded portion. Therefore, means for lining the buffer sheet without using an adhesive as much as possible. Is desired.

An example of an envelope in which a buffer sheet is lined without using an adhesive is disclosed in Japanese Utility Model Publication No. 64-1241. This envelope has a sheet body in which a plastic film is laminated on the entire surface of one side of the paper-like sheet, and a sheet body on which a bubble sheet is further stacked, with the bubble sheet surfaces facing each other, and the open edges other than the edge which becomes the opening of the envelope, In addition to the thermal welding with a bubble sheet interposed, the bubble sheet at the periphery serving as an envelope opening is thermally welded to a paper sheet laminated with a plastic film.

[0005] This buffer envelope has the advantage that it can be manufactured without an adhesive, but since the laminated plastic film is very firmly fixed to the paper sheet, the paper section and the plastic section are separated and recycled after use. It can not be turned to waste, and there is a problem of polluting the environment at the time of disposal.

On the other hand, as a buffer envelope in which the use of an adhesive is suppressed as much as possible, there is a buffer envelope described in Japanese Patent No. 2978161 by the present inventor. FIG. 9 shows an example of the production line. In this production line, front and back paper-like sheets 51 and 52 wound around a coil are supplied from above and below, and between them, two bubble sheets 53 serving as buffer sheets similarly wound around a coil are supplied while being folded in two. The buffer envelopes are arranged in two rows with the openings 54 facing outward in the width direction of the production line.

As shown in FIG. 10 on an enlarged scale, a pair of upper and lower injection nozzles 55 are provided on both sides of the entry side where the paper sheets 51 and 52 and the folded bubble sheet 53 are overlapped.
Are arranged, and the adhesive 5
6 is applied. On its downstream side, a pair of upper and lower thermocompression bars 58 for thermally welding the bubble sheet 53 at a portion to be the edge of the opening 54 and a portion to be the edge 57 at the bottom of the envelope,
59 are further disposed, and further downstream thereof, a thermocompression bonding bar 61 for thermally welding the bubble sheet 53 at a portion to be the edge 60 at both width ends of the envelope is disposed. In the place where the thermocompression bonding bar 58 is arranged, the two-folded bubble sheet 53
When the bakelite plate 62 is inserted between them, and the bubble sheet 53 on the edge of the opening 54 is thermally welded to each of the paper sheets 51 and 52, the upper and lower bubble sheets 53 are prevented from welding to each other.

In the heat-welded portion at the periphery of the opening 54, the temperature of the thermocompression bonding bar 58 cannot be raised too high in order to prevent the bubble sheet 53 from fusing with the bakelite plate 62. The fluidity of the bubble sheet 53 on the side that comes into contact with the sheets 51 and 52 is insufficient, and the bubble sheet 53 cannot be sufficiently thermally welded. The adhesive 56 is used to compensate for the shortage of the heat welding.

The buffer envelope manufactured by the above-mentioned manufacturing line can easily separate the paper portion and the plastic portion after use, and can be recycled to prevent environmental pollution. Since some adhesives need to be used, the above-mentioned problems in using the adhesives remain.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a buffer sheet that can be thermally welded to a paper sheet at a low heating temperature, and a buffer sheet that is lined with a paper sheet without an adhesive. An object of the present invention is to provide a buffer envelope that can be easily separated.

[0011]

In order to solve the above-mentioned problems, a buffer sheet according to the present invention comprises a plurality of plastic films stacked one on top of the other and a buffer portion formed between the plastic films stacked one above the other. In the sheet, at least one of the plastic films forming the upper and lower surfaces of the cushioning sheet has a melting point of 125 ° C.
The structure formed of the following synthetic resin was adopted.

That is, by forming the plastic film on at least one surface of the buffer sheet with a synthetic resin having a melting point of 125 ° C. or less, the low melting point synthetic resin has high fluidity even at a low heating temperature. In addition, the surface of the paper sheet was made to be hardly uneven, so that the buffer sheet could be thermally welded to the paper sheet at a low heating temperature.

[0013] As the cushioning sheet, the cushioning portion may be:
A number of independent air-filled portions formed between the plastic films stacked one above the other can be employed.

As the synthetic resin having a melting point of 125 ° C. or less, a metallocene unit, a linear low-density polyethylene unit,
Alternatively, any of a mixture of at least one of metallocene and linear low-density polyethylene can be employed.

Further, the cushioning envelope of the present invention is characterized in that a plurality of plastic films are stacked one on top of the other, and two buffer sheets, each having a buffer portion formed between the plastic films stacked one on top of the other, are inserted between the facing front and back paper sheets. The two buffer sheets are heat-welded to each other at the open edge other than the edge that becomes the opening of the envelope, and each of the buffer sheets is heat-welded to the paper-quality sheet. In a buffer envelope in which an opened edge is closed except for an edge serving as an opening, the buffer sheet according to any one of claims 1 to 3 is used as each of the buffer sheets. A structure in which a side where a plastic film is formed of a synthetic resin having a melting point of 125 ° C. or less is directed toward each of the paper sheets, and the buffer sheets are heat-sealed to the paper sheets at an edge of the envelope opening. And use.

[0016] That is, the buffer sheet to be lined with the paper-like sheet has a plastic film on at least one surface formed of a synthetic resin having a melting point of 125 ° C or less.
The plastic film of this buffer sheet has a melting point of 125 ° C.
With the side formed of the following synthetic resin facing the paper sheet on the front and back, each buffer sheet is thermally welded to the paper sheet at the edge of the envelope opening, so that the low melting point synthetic resin has fluidity even at a low heating temperature. The buffer sheet can be fixed to the paper sheet without an adhesive even at the edge of the envelope opening where the heating temperature cannot be set high, by holding the buffer sheet. The reason why the melting point of the synthetic resin is set to 125 ° C. or less is that the upper limit of the heating temperature allowed in the heat welding portion at the periphery of the envelope opening is around 130 ° C.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 (a) and (b)
1 shows a buffer sheet according to a first embodiment. This buffer sheet is a three-layered bubble sheet 1, in which an intermediate film 4 having irregularities is stacked between upper and lower cover films 2 and 3, and a number of independent films are provided between the upper cover film 2 and the intermediate film 4. An air enclosure 5 is formed. The upper cover film 2 and the intermediate film 4 are formed of ordinary low density polyethylene, and the lower cover film 3 is formed of linear low density polyethylene having a melting point of 105 ° C. In addition, the upper cover film 2 side or both upper and lower cover films 2,
3 may be formed of linear low density polyethylene. The intermediate film 4 may also be a linear low-density polyethylene.

FIGS. 2A and 2B show a buffer sheet according to a second embodiment. The cushioning sheet is a two-layered bubble sheet 6 in which a number of independent air enclosing portions 9 are formed between a lower film 8 and an upper film 7 having irregularities. The upper film 7 is formed of ordinary low density polyethylene, and the lower film 8 has a melting point of 10 which is a kind of metallocene.
It is formed of titanocene at 0 ° C. The upper film 7 or both the upper and lower films 7, 8 may be formed of titanocene.

FIG. 3 shows a cushioning sheet according to a third embodiment. This buffer sheet is composed of upper and lower cover films 10, 1
1 and a foamed polyethylene sheet 12 is laminated. The lower cover film 11 is formed of a resin obtained by mixing 15% of titanocene with polypropylene, and has a melting point of 120 ° C. The upper cover film 10 is formed of ordinary polypropylene. The mixing ratio of titanocene may be any value as long as the melting point of the resin is 125 ° C. or less, and can be appropriately increased or decreased. Further, the foamed polyethylene sheet 12 as a cushioning material
In place of this, agricultural products such as wheat and corn can be crushed and hardened.In this case, the surplus agricultural products can be used effectively and disposed after use without polluting the environment. be able to.

In each of the above embodiments, the melting point is 125 ° C.
As the following low melting point resin, a resin obtained by mixing linear low density polyethylene, titanocene and titanocene was used, but other low melting point resins and mixed resins thereof can also be used.

FIGS. 4 and 5 show a buffer envelope according to the first embodiment. As shown in FIGS. 4 (a) and 4 (b), the cushioning envelope has two bubble sheets 1 shown in FIG. 1 sandwiched between the front-side paper sheet 13 and the back-side paper sheet 14 of the envelope. The edges 16 at both width ends and the bottom edge 17 of the envelope except for the edge of the envelope opening 15 are hermetically sealed by heat welding of the bubble sheet 1.
Are thermally welded to the front paper sheet 13 and the back paper sheet 14, respectively. A folded portion 18 is provided on the upper side of the sheet-like paper sheet 13, and a double-sided adhesive tape 19 for closing the mouth and a cover tape 20 covering the double-sided adhesive tape 19 are attached to the folded portion 18.

As shown in FIG. 5 in an enlarged manner, each bubble sheet 1 has the lower cover film 3 formed of the above-mentioned linear low-density polyethylene facing the paper sheets 13 and 14, and the edge of the opening 15. The paper sheets 13 and 14 are heat-sealed without an adhesive, and the bubble sheet 1 in this portion is thinned by heat-sealing, and is formed into a smooth shape so that the enclosed articles are not caught.

FIG. 6 shows a production line for the buffer envelope. This production line differs from the production line shown in FIGS. 9 and 10 only in that an adhesive injection nozzle is not provided. Front and back paper sheets 13 and 1 wound on coils
4 are supplied from above and below, while two bubble sheets 1 also wound around a coil are supplied while being folded in two, and the buffer envelope is taken in two rows with its opening 15 facing outward in the width direction of the production line. It is supposed to be.

At the downstream side of the place where the paper sheets 13 and 14 and the folded bubble sheet 1 are overlapped, an opening 1 is provided.
A pair of upper and lower thermocompression bonding bars 21 and 22 for heat-sealing the bubble sheet 1 at a portion to be the edge of the envelope 5 and a portion to be the edge 17 at the bottom of the envelope are arranged, and further downstream thereof, A thermocompression bonding bar 23 for heat-welding the bubble sheet 1 at a portion to be the edge 16 at both width ends is disposed. As shown in an enlarged manner in FIG. 7, at the place where the thermocompression bonding bar 21 is disposed, the bakelite plate 24 is inserted between the two-folded bubble sheets 1, and the bubble sheets 1 on the periphery of the opening 15 are separated from the paper sheets 13, At the time of heat welding to 14, the upper and lower bubble sheets 1 are prevented from welding to each other.

The temperature of the thermocompression bonding bar 21 is raised to 150 ° C., and the actual temperature of the heat-welded portion at the periphery of the opening 15 is 13 ° C.
It was around 0 ° C. The thermocompression bars 22 and 23 are 2
The temperature has been raised to 20 ° C.
The actual temperatures of the heat-welded portions in 6 and 17 were around 200 ° C.

The paper sheets 13 and 14 and the bubble sheet 1 are intermittently sent out with a stroke corresponding to the width of the envelope, and the heating and pressing bars 21, 22 and 23 are operated at the same time, and Heat welded. Downstream of these heat-welded portions, although not shown, a slitter for dividing a continuous sheet of an envelope body that has been welded and integrated into two sections at the center of the welded width, and a shear for cutting into a width of the envelope. Is installed, and a buffer envelope is manufactured continuously.

The production line shown in FIG.
This production line is easy to use.
It can be changed to the arrangement of the line picking. Instead of supplying the bubble sheet by folding it from both sides, it is also possible to supply two bubble sheets one above the other.

FIGS. 8A and 8B show a buffer envelope according to a second embodiment. This buffer envelope is also used as the first buffer sheet.
In this embodiment, the paper sheet 25 on the front and back and the bubble sheet 1 to be lined are folded in two at the bottom of the envelope, and the thermal welding at the bottom edge of the envelope is omitted. . The rest is the same as the buffer envelope of the first embodiment, and the bubble sheet 1 has a lower cover film 3 formed of linear low-density polyethylene on the side of the paper sheet 2.
5 and is thermally welded to the paper sheet 25 on the edge of the opening 26 without an adhesive.

In each of the above embodiments of the buffer envelope, a three-layer bubble sheet is used as the buffer sheet. However, the two-layer bubble sheet shown in FIGS. be able to.

[0030]

As described above, in the buffer sheet of the present invention, the plastic film on at least one surface of the buffer sheet is formed of a synthetic resin having a melting point of 125 ° C. or less. The synthetic resin has high fluidity and is hardly uneven on the surface of the paper sheet, and the buffer sheet can be thermally welded to the paper sheet at a low heating temperature.

Further, in the buffer envelope of the present invention, the buffer sheet to be lined with the paper sheet has at least one plastic film on one surface formed of a synthetic resin having a melting point of 125 ° C. or less. Since the side formed of the synthetic resin having a melting point of 125 ° C. or less is directed to the front and back paper sheets and each of the buffer sheets is heat-welded to the paper sheet, the low-melting synthetic resin has fluidity at a low heating temperature. In addition, the buffer sheet can be fixed to the paper sheet without the adhesive even at the edge of the envelope opening where the heating temperature cannot be set high.

[Brief description of the drawings]

FIG. 1A is an external perspective view showing a cushioning sheet according to a first embodiment, and FIG. 1B is a longitudinal sectional view of a.

FIG. 2A is an external perspective view illustrating a cushioning sheet according to a second embodiment, and FIG.

FIG. 3 is a longitudinal sectional view showing a cushioning sheet according to a third embodiment.

FIG. 4A is an external perspective view showing the buffer envelope of the first embodiment, and FIG.

FIG. 5 is an enlarged vertical sectional view of a main part of FIG. 4;

FIG. 6 is a perspective view schematically showing a production line for the buffer envelope of FIG. 4;

FIG. 7 is an enlarged sectional view taken along line VII-VII in FIG. 6;

FIG. 8A is an external perspective view showing a buffer envelope according to a second embodiment, and FIG.

FIG. 9 is a perspective view schematically showing a conventional buffer envelope production line.

FIG. 10 is an enlarged perspective view of a main part of FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bubble sheet 2, 3 Cover film 4 Intermediate film 5 Air sealing part 6 Bubble sheet 7, 8 Film 9 Air sealing part 10, 11 Cover film 12 Foamed polyethylene sheet 13, 14 Paper sheet 15 Opening 16, 17 Edge 18 Folding part Reference Signs List 19 double-sided adhesive tape 20 cover tape 21, 22, 23 thermocompression bonding bar 24 bakelite plate 25 paper sheet 26 opening

Claims (4)

[Claims] 1. A buffer sheet in which a plurality of plastic films are vertically stacked and a buffer portion is formed between the vertically stacked plastic films, and at least one of the plastic films forming the upper and lower surfaces of the buffer sheet. A buffer sheet, one of which is formed of a synthetic resin having a melting point of 125 ° C. or less. 2. The cushioning sheet according to claim 1, wherein the cushioning portion is a number of independent air enclosing portions formed between the plastic films stacked one above the other. 3. The synthetic resin having a melting point of 125 ° C. or less,
The buffer sheet according to claim 1, wherein the buffer sheet is one of a metallocene simple substance, a linear low-density polyethylene simple substance, and a mixture of at least one of a metallocene and a linear low-density polyethylene. 4. An envelope wherein a plurality of plastic films are vertically stacked, and two buffer sheets each having a buffer portion formed between the vertically stacked plastic films are interposed on the entire surface between the opposing front and back paper sheets. The two buffer sheets are thermally welded to each other at an open edge other than the edge that becomes the opening of each other, and each of the buffer sheets is thermally welded to the paper material sheet, excluding the edge that becomes the envelope opening. In a shock-absorbing envelope in which an opened edge is sealed, the shock-absorbing sheet according to any one of claims 1 to 3 is used as each of the shock-absorbing sheets,
With each of these buffer sheets facing the respective paper-quality sheets, the side on which the plastic film on the surface is formed of a synthetic resin having a melting point of 125 ° C. or lower is heated at the periphery of the envelope opening. A buffer envelope characterized by being welded.