JP2004299786A - Recyclable binding tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a binding tape which has a high-speed sealing performance and a high sealing strength, is excellent in a disaggregative property and is suitable for recycling of paper. <P>SOLUTION: The recyclable binding tape is provided with an adhesive layer comprising a thermocompression bonding hot melt composition containing an ethylene-vinyl acetate copolymer and a tackifying resin on a paper-made taping base material. The thermocompression bonding hot melt composition may further contain a wax, a suitable thermocompression bonding hot melt composition is a composition containing ethylene-vinyl acetate copolymer of 10 to 90 wt%, tackifying resin of 5 to 70 wt% and wax of 5 to 50 wt%, in addition, it is preferred that the polymerization quantity of a vinyl acetate component in the ethylene-vinyl acetate copolymer is 1 to 20 wt%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a recyclable paper binding tape.

  In recent years, all materials have been required to be recyclable from the viewpoint of global environmental protection, and paper binding tapes widely used for binding used paper, documents, booklets, and bills are no exception.

  By the way, the binding tape is excellent in processability and low cost, and has an advantage that it is suitable for high-speed binding. Therefore, an olefin polymer such as polyethylene or polypropylene is laminated on a paper tape base material. Things are widely used.

  However, the conventional binding tape is not sufficiently disintegrated by a disintegrator in the pulping process for recycling because the coating strength of the resin layer is too strong, and is insoluble in water. The obtained olefin-based resin layer remained as a film, which was unsuitable for recycling. Therefore, for example, if the above-mentioned binding tape is used for transporting and storing used paper in the recycling process, it cannot be put into the recycling process together with the used paper, so a separate process of separating the binding tape from the used paper is required. Therefore, there is a problem that workability and economic efficiency of the recycling process are impaired.

In order to solve such a problem, a binding tape in which a paper tape base material is impregnated with polyvinyl alcohol and glycerin has been proposed (for example, see Patent Document 1).
JP-A-2002-173170 (Claims)

  However, in the case of this binding tape, although it has recyclability that could not be obtained with the above-mentioned olefin resin type binding tape, productivity is poor because a drying step by emulsion is necessary, and in the drying step, There has been a problem that curling that causes tape clogging in a high-speed binding machine occurs. In addition, there is a problem that the performance related to the sealing time and the sealing strength required at the time of binding is low and not practical.

  The present invention has been made in view of the above problems, and has an object to provide a binding tape having high-speed sealing property and high sealing strength, excellent in disintegration properties, and suitable for recycling used paper and the like. I do.

  As a result of intensive studies to achieve the above object, the present invention has been completed. That is, the present invention is characterized in that an adhesive layer made of a thermocompression-bondable hot melt composition containing an ethylene-vinyl acetate copolymer and a tackifier resin is provided on a paper tape base material. It is a recyclable binding tape.

  In the present invention, the thermocompression-bondable hot melt composition may further contain a wax, and a preferable thermocompression-bondable hot melt composition is 10 to 90% by weight of an ethylene-vinyl acetate copolymer, 5 to 70% by weight. A composition containing, by weight, a tackifying resin and 5 to 50% by weight of a wax. Further, the polymerization amount of the vinyl acetate component in the ethylene-vinyl acetate copolymer is preferably 1 to 20% by weight.

  The binding tape of the present invention is provided with an adhesive layer made of a thermocompression-bonding hot melt composition containing an ethylene-vinyl acetate copolymer and a tackifier resin on a paper tape base material. In addition, the film strength of each composition in the binding tape can be kept low, and as a result, defibration by a defibrillator becomes possible in the pulping step at the time of recycling.

  Therefore, according to the present invention, it is possible to recycle waste paper or the like even with the binding tape attached, and as a result, it becomes unnecessary to separate the binding tape before the recycling step, which has been conventionally required, so that recycling is extremely difficult. This makes it easy and can greatly reduce the recycling cost.

  In addition, since the adhesive layer has the above-described configuration, high-speed sealing properties and high sealing strength can be obtained, and the binding operation can be performed smoothly.

  Hereinafter, embodiments of the present invention will be described.

  The binding tape of the present invention has an adhesive layer made of a thermocompression-bonding hot melt composition containing an ethylene-vinyl acetate copolymer and a tackifier resin on a long paper tape base material having a predetermined width. It is provided and wound in a roll shape.

  The adhesive layer does not need to be provided over the entire surface of the tape base material, so that the adhesive layer is present on at least one of the cut ends when cut for each predetermined length required for bundling. It may be provided intermittently at predetermined intervals along the longitudinal direction of the tape base material.

  Further, the adhesive layer is provided by laminating on a paper tape base material, but is not limited thereto.

Examples of the paper tape base material include, for example, kraft paper, but the type thereof is not particularly limited, provided that the base material has strength as a binding tape and the base material itself can be recycled. Paper having a basis weight of 50 to 200 g / m ² is suitable.

  In the present invention, the thermocompression-bonding hot melt composition containing the ethylene-vinyl acetate copolymer and the tackifier resin used in the adhesive layer is used when performing thermocompression bonding at a low temperature (70 to 140 ° C.). Is especially effective for

  The blending ratio of the ethylene-vinyl acetate copolymer is preferably from 10 to 90% by weight, more preferably from 20 to 80% by weight, in the thermocompression-bonding hot melt composition. If the compounding ratio is less than 10% by weight, the thermocompression bonding property is deteriorated, and if it exceeds 90% by weight, the defibration property may be deteriorated. In the ethylene-vinyl acetate copolymer, the polymerization amount of the vinyl acetate component is preferably 1 to 20% by weight, more preferably 3 to 18% by weight. It is difficult to obtain an ethylene-vinyl acetate copolymer having a polymerization amount of less than 1% by weight, and if it exceeds 20% by weight, recyclability may be deteriorated.

  The tackifier resin has an effect of improving the disintegration and thermocompression bonding properties of the thermocompression hot melt composition. Examples of the tackifying resin include a terpene resin, an aliphatic resin, an alicyclic resin, an aromatic resin, a coumarone-indene resin, a rosin and a derivative thereof, and any of these can be used. Is also good. From the viewpoint of thermocompression bonding, terpene resins and rosin are preferable among the above.

  The compounding ratio of the tackifier resin is preferably 5 to 70% by weight, more preferably 10 to 60% by weight in the thermocompression-bonding hot melt composition. If the compounding ratio is less than 5% by weight, the disintegration property is deteriorated, and if it exceeds 70% by weight, the thermocompression bonding property may be deteriorated.

  The softening point of the tackifier resin is preferably from 70 to 190C, more preferably from 100 to 190C. If the softening point is less than 70 ° C., tackiness is likely to occur, and when the processed binding tape is recycled, the dryer tends to have a pitch in the drying step. On the other hand, resins having a softening point exceeding 190 ° C. are difficult to obtain from the market.

  The thermocompression-bondable hot melt composition may further contain a wax. Examples of the wax include paraffin wax, microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, and polypropylene wax. Wax has the effect of reducing the tack of the thermocompression-bondable hot melt composition and increasing the thermocompression bonding property. Any of the above may be used as the wax, but a wax having a melting point of 100 to 180 ° C is preferable. When a wax having a melting point of less than 100 ° C. is used, pitch is easily formed during recycling. On the other hand, it is difficult to obtain wax having a melting point exceeding 180 ° C. from the market.

  The mixing ratio of the wax is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, in the thermocompression-bonding hot melt composition. If the mixing ratio is less than 5% by weight, pitch tends to be formed during recycling, and if it exceeds 50% by weight, the thermocompression bonding property may be deteriorated.

  It is desirable to adjust the melt flow rate (MFR) of the thermocompression-bondable hot melt composition so that the dryer does not have a pitch in the drying step of recycling and is suitable for T-die extrusion coating. 500 g / 10 min is preferable, 1 to 300 g / 10 min is more preferable, and 1 to 200 g / 10 min is particularly preferable.

  Here, the MFR is an index indicating the fluidity of the resin. A material is placed in a cylinder having an orifice having a diameter of 2.1 mm and a length of 8 mm, and a load of 2160 g is applied at 190 ° C. (230 ° C. in the case of polypropylene). To extrude the molten material, measure the weight of the material that has flowed out in 5 to 240 seconds, and convert it to the number of grams per 10 minutes. The larger the MFR value, the better the fluidity. (See JIS-K-7210).

  In the present invention, if necessary, the thermocompression-bonding hot melt composition may be, for example, a filler such as calcium carbonate, titanium oxide, barium sulfate, talc, clay, or carbon black, a lubricant, an antifogging agent, or an oxidizing agent. Known additives usually used in hot melt compositions, such as an inhibitor, an ultraviolet absorber, a flame retardant, a colorant, a plasticizer, and an oil, may be added.

  The binding tape of the present invention is obtained by forming an adhesive layer on paper by using the above-mentioned thermocompression-bonding hot melt composition, for example, by a method such as T-die extrusion coating and a roll coater. The binding tape obtained in this manner has a good adhesive property, when subjected to thermocompression bonding, having an adhesive strength of 400 gf / 15 mm or more, particularly 500 gf / 15 mm or more in a T-peel test.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example A T-die extrusion coating of a thermocompression-bondable hot melt composition containing 60% by weight of an ethylene-vinyl acetate copolymer (polymerization amount of vinyl acetate: 10% by weight), 30% by weight of a tackifier resin, and 10% by weight of a wax. Thus, an adhesive layer was formed on kraft paper having a basis weight of 75 g / m ² to obtain a binding tape. For the evaluation of the thermocompression bonding property, T-peel tests were performed three times at the temperatures shown in Table 1 and the average value was shown in the graph of FIG.

＜Ｔ型剥離試験＞
接着面：接着剤層同士
引張強度：２００ｍｍ／ｍｉｎ
熱圧着時のプレス圧力：３ｋｇｆ／ｃｍ²
熱圧着時のプレス時間：２秒
表１および図３より、実施例の結束テープは、いずれの温度で熱圧着した場合でも、５００ｇｆ／１５ｍｍ以上という良好な接着性を有することがわかる。また、この結束テープを帯封機に掛けたところ、問題なく良好に接着した。さらに、この結束テープをオーバーテープシール離解機に掛けたところ、問題なく良好に離解した。

<T-type peel test>
Adhesive surface: Tensile strength between adhesive layers: 200 mm / min
Press pressure during thermocompression bonding: 3 kgf / cm ²
Pressing time at the time of thermocompression bonding: 2 seconds From Table 1 and FIG. 3, it can be seen that the binding tape of the example has a good adhesive property of 500 gf / 15 mm or more even when thermocompression bonding is performed at any temperature. Further, when the binding tape was put on a banding machine, it adhered well without any problem. Further, when the binding tape was applied to an over-tape seal disintegrator, it was disintegrated well without any problem.

  Since the binding tape of the present invention is recyclable itself, the waste paper can be recycled even with the binding tape attached, and the recycling is extremely easy.

It is a graph which shows the adhesive strength by the T-peel test of the binding tape of an Example.

Claims (4)

  A recyclable binding tape comprising a paper tape substrate provided with an adhesive layer comprising a thermocompression-bondable hot melt composition containing an ethylene-vinyl acetate copolymer and a tackifier resin. The recyclable tie tape according to claim 1, wherein the thermocompression-bondable hot melt composition further contains a wax. 3. The thermocompression-bondable hot melt composition contains 10 to 90% by weight of an ethylene-vinyl acetate copolymer, 5 to 70% by weight of a tackifier resin and 5 to 50% by weight of a wax. Recyclable unity tape. The recyclable binding tape according to any one of claims 1 to 3, wherein the polymerization amount of the vinyl acetate component in the ethylene-vinyl acetate copolymer is 1 to 20% by weight.

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