JPH0226833Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a double-walled envelope with cushioning properties, and in particular, it is made by adding a heat-melting resin such as polyethylene to cellulose fibers such as pulp, and using a dry method. A pine-like sheet is formed, and this is heated to above the melting point of the above-mentioned meltable resin in a hot atmosphere, and the cushioning sheet made by bonding the fibers with this resin is used as the surface material and inner surface material of the double envelope. This relates to a cushioning envelope placed between the

[Prior Art and Problems] In recent years, double-walled envelopes with a buffer layer on the inside have been used as shipping bags for storing and transporting cassette tapes, video tapes, floppy disks, etc., or as transport bags for small items that are easily damaged. It is being used more and more often.

This kind of double envelope is known to have a structure in which, for example, crushed waste paper such as newspaper is disposed as a cushioning material between the surface material and the inner surface material. This cushioning material made of waste paper is fixed to the inner and outer surfaces of the double envelope using an adhesive applied to the inner surfaces of the inner and outer surfaces, but this material has the following drawbacks. In other words, the cushioning properties of the above-mentioned cushioning material layer improve as the thickness increases, but since the cushioning materials are not individually bonded, the thicker the cushioning material layer becomes, the more the weight of the cushioning material itself or the external There is a drawback that the loose cushioning material is partially displaced by the impact, resulting in uneven thickness. Additionally, thickening the cushioning material layer increases the weight, which also has the disadvantage of increasing postage costs.

Although there are envelopes with a foamed plastic sheet, blister sheet, etc. pasted on the inside of the envelope, they cannot be used in large quantities because of disposal problems.

[Means for solving the problems] The present invention aims to solve the above-mentioned conventional technology, and is based on cellulose fibers,
A small amount of non-foaming hot-melt resin is added to this, a mat-like sheet is formed by a dry method, and the sheet is heated above the melting point of the hot-melt resin, and adjacent fibers are fused and bonded using the hot-melt resin. The cushioning sheet consisting of 2
It is an object of the present invention to propose a cushioning envelope characterized by being disposed between a surface material and an inner surface material of a double envelope.

[Function] The cushioning sheet placed between the envelope's surface material and inner surface material is made of heat-melting resin and the adjacent fibers are fused and bonded, so it does not move due to its own weight or external force, so it is used. No unevenness occurs inside. Moreover, the buffer sheet can be formed by a dry method, and a fluffy sheet with large cushioning properties can be obtained.

[Example] Hereinafter, the present invention will be specifically described with reference to the accompanying drawings.

FIG. 1 is a plan view of the envelope of the present invention, and FIG. 2 is a longitudinal sectional view thereof.

Reference numeral 1 indicates the envelope of the present invention, and the elongated surface material 2
It consists of an inner surface material 3 of approximately the same size as , and a cushioning sheet 4 described later. Surface material 2 and inner material 3
The cushioning sheet 4 is made of a known strong material such as kraft paper, and after the two are overlapped and the cushioning sheet 4 is sandwiched therein, the peripheral edge of the cushioning sheet 4 is sealed to seal the cushioning sheet 4. The envelope material thus obtained is further folded into two and the opposite edges are joined to form the double envelope 1 shown in FIG. 1.

Now, the cushioning sheet 4 used in the envelope of the present invention
is mainly made of cellulose fibers such as wood pulp, and is formed by adding a small amount of heat-melting resin such as polyethylene. That is, for example, a pine-like sheet is formed by a dry method using a material obtained by uniformly mixing 70 to 98% by weight of cellulose fiber and 2 to 30% by weight of powder or fibrous thermofusible resin in a dry state. After that, this is exposed to a hot atmosphere and heated to a temperature higher than the melting point of the thermofusible resin, and the adjacent fibers are fused and bonded with this meltable resin, and then cooled to produce the cushioning sheet used in the present invention. 4 is obtained.

Example 1 A mixture of 85% by weight of wood pulp and 15% by weight of fibrous polyethylene (trade name: SWP: manufactured by Mitsui Petrochemicals) was used as a material, and was made into a sheet with a weight of 13g/m ² by a dry method, which was further laminated. The material was made into a 400 g/m ² mat shape, and then exposed to a heat atmosphere at 145° C. for a short period of time. The sheet obtained after cooling has an apparent density of 0.04
g/cc and had good buffering properties.

This cushioning sheet is made of bleached kraft paper, with a cover (surface material) of 120 g/m ² and a backing paper (inner material) of 80 g/m ²
A double envelope as shown in FIG. 1 was formed by sandwiching the envelope between the envelopes.

When a cassette tape was stored in this envelope and subjected to a transportation test, the cassette tape was not damaged and the envelope showed excellent cushioning properties.

[Effects of the invention] According to the invention having the above structure, the cushioning sheet constituting the cushion layer disposed between the surface material and the inner surface material of the envelope is mainly made of cellulose fibers such as wood pulp. The structure is such that a small amount of non-foaming hot-melt resin is added to this to form a mat-like sheet using a dry method, and then this is heated and adjacent fibers are fused and bonded using the hot-melt resin. (b) A cushioning sheet that increases the integrity of the structure so that only the cushion layer between the outer surface material and the inner surface material of the envelope will not move and cause shifting even if it is subjected to its own weight or external force during use. can be easily formed by a dry method, and the cushioning sheet is fluffy and flexible and exhibits excellent cushioning properties. C. The cushioning sheet is mainly made of cellulose fibers. Therefore, even if it is incinerated after use, it will not generate high heat and damage the incinerator, and it will not generate toxic gas, so it is easy to dispose of. As a shipping bag or a mailing envelope, it is possible to obtain a double-walled envelope that is lightweight, has excellent cushioning properties, and is easy to incinerate after use.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a cushioning envelope according to the present invention, and FIG. 2 is a longitudinal sectional view thereof. 1...Double envelope, 2...Surface material, 3...Inner surface material, 4...Buffer sheet.

Claims (1)

[Scope of utility model registration request] A mat-like sheet made of cellulose fibers as a main ingredient and a small amount of non-foamable thermofusible resin added thereto by a dry process is heated to a temperature higher than the melting point of the thermofusible resin, and the mat-shaped sheet is made of cellulose fibers, and a mat-like sheet formed by a dry process is heated to a temperature higher than the melting point of the thermofusible resin. A cushioning envelope characterized in that a cushioning sheet formed by fusion bonding fibers is disposed between a surface material and an inner surface material of a double envelope.