JPH073218A - Adhesive tape and its production - Google Patents

Abstract

PURPOSE:To obtain an adhesive tape excellent in adhesiveness, useful for e.g. fixing automotive internal trim or facing materials, and enabling the PP-based molded form as the substrate therefor to be recycled without needing being peeled off the substrate, by providing the surface of a base sheet consisting mainly of a PP-based resin with a specific tack agent layer. CONSTITUTION:The objective adhesive tape can be obtained by providing (A) the surface of a base sheet consisting mainly of a PP-based resin with (B) a tack agent layer prepared by incorporating (1) 100 pts.wt. of a hydrogenated block copolymer of formula A-B-A or A-B (A is styrene polymer block; B is olefin polymer block obtained by hydrogenating butadiene polymer block or isoprene polymer block) with (2) 10-200 pts.wt. of a hydrogenated petroleum resin or terpene resin. Specifically, this adhesive tape can be produced by co- extrusion in a molten state of a resin for the base sheet and the tacky agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive tape comprising a base sheet made of a polypropylene resin and a pressure-sensitive adhesive layer having high compatibility with polypropylene, and more specifically, a polyethylene molded article to which the pressure-sensitive adhesive tape is attached. The present invention relates to an adhesive tape that does not need to be peeled off when recycled or reused.

[0002]

2. Description of the Related Art Conventionally, polypropylene resins have been widely used in these fields as molding materials for housings of electronic and electric products and interior and exterior members of automobiles. Adhesives and adhesive tapes have been conventionally used to bond these polypropylene-based molded articles as adherends,
In recent years, along with the recycling and reuse of polypropylene-based molded products, a process for removing these adhesives and adhesive tapes has become necessary. Particularly in adhesive tapes, acrylic and rubber adhesives are preferably used as adhesives, but this type of adhesives has poor compatibility with polypropylene and is present as foreign matter if the adhesives are mixed during polypropylene regeneration. , Polypropylene-based molded products cannot be recycled.

As a countermeasure against this, Japanese Unexamined Patent Publication (Kokai) No. 3-64381 proposes a method of peeling the adhesive tape from the adherend by heating, and Japanese Unexamined Patent Publication No. 4-88075 (Japanese Unexamined Patent Publication No. 4-88075) removes the adhesive tape from the adherend. Masking materials have been proposed.

However, although there is an advantage that the peeling work can be easily carried out by using these methods and the masking material, there is a limitation that the process such as heating is required and the heat resistance and the ultraviolet resistance of the adhesive tape itself are limited, There is a drawback that the original adhesive performance of the adhesive tape cannot be fully exhibited.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an adhesive tape which can reproduce a polypropylene-based molded product as it is attached without peeling off the adhesive tape attached to the polypropylene-based molded product. is there. More specifically, when a polypropylene-based molded product is regenerated, the molded product is finely divided into chips and subjected to melt molding such as injection molding or extrusion molding. By performing compatibilization or dispersion with the polypropylene resin during the melt molding, The object of the present invention is to provide an adhesive tape which can be recycled without peeling it off.

[0006]

The pressure-sensitive adhesive tape according to the present invention has been devised in order to achieve the above-mentioned object, and has a general formula AB on at least one surface of a base material sheet containing a polypropylene resin as a main component. -A or AB (in the formula, A means a styrene polymer block, B means an olefin polymer block obtained by hydrogenating a butadiene polymer block or an isoprene polymer block, respectively). An adhesive layer formed by mixing 10 to 200 parts by weight of a hydrogenated petroleum resin or a hydrogenated terpene resin with 100 parts by weight of the obtained block copolymer is formed.

[0007] Hydrogenated petroleum resin or hydrogenated terpene resin is a substance having a high compatibility with polypropylene.

The adhesive tape according to the present invention will be described below.
Further details will be described.

The base sheet containing polypropylene resin as a main component is composed of polypropylene alone or a blend of polypropylene and another polyolefin resin such as polyethylene resin or polypropylene elastomer. In the case of a blended body, there is a method of melt-kneading a polypropylene resin and another resin, or a method of obtaining a mixture in the process of polymerizing each resin by a method such as so-called reactor blending. The thickness of the sheet is selected depending on the application, but the range that can be suitably used as an adhesive tape is 1
It is about 0 to 100 μm.

In the hydrogenated block copolymer represented by the general formula ABAA or AB, the styrene polymer block A has an average molecular weight of 12000 to 1000.
Those having a glass transition temperature of 20 ° C. or higher are preferable. Further, a polymer block B obtained by hydrogenating a butadiene polymer block or an isoprene polymer block has an average molecular weight of 10,000 to 3
Approximately 00000, glass transition temperature-2
It is preferably 0 ° C. or less. A-B-A and A-B can be used alone, but can also be used in combination. In the case of mixing, the weight ratio of both (A-B-A / A-B)
Is usually preferably about 100/0 to 50/50. A commercially available product of such a block copolymer is Kraton G.
1650 (manufactured by Shell Chemical Co., Ltd.), Kraton G1652
(Manufactured by Shell Chemical Co., Ltd.), Tuftec H1052 (manufactured by Asahi Kasei Corporation), and Septon 2023 (manufactured by Kuraray Co., Ltd.).

The hydrogenated petroleum resin is, for example, a hydrogenated C9 petroleum resin obtained by cationically polymerizing a C9 fraction obtained by cracking naphtha, or C5 mainly containing cyclopentadiene.
It is a petroleum resin obtained by thermal polymerization of dicyclopentadiene derived from a fraction or a C5 fraction, and is an alicyclic petroleum resin. Α-Methylstyrene, vinyltoluene, vinylxylene, propenylbenzene, indene, methylindene, etc. are contained as a polymerization component in the C9 fraction, and the C9 fraction is usually available as a mixture of the polymerizable components. In addition, in the hydrogenation of these petroleum resins, a metal such as nickel, palladium, cobalt, ruthenium, platinum, rhodium, or an oxide thereof is usually used as a hydrogenation catalyst at a temperature of 200 to 300 ° C. and a pressure of 1 ° C.
Conditions of 0 to 300 kg / cm ² are adopted.

The hydrogenated terpene resin is
A terpene resin obtained by cationically polymerizing a terpene fraction such as α-pinene, β-pinene and dipentene using a Friedel-Crafts catalyst such as aluminum chloride and boron trifluoride is hydrogenated. The same method as that of the above-mentioned petroleum resin is adopted for the hydrogenation. Typical examples of commercially available products of such hydrogenated terpene resins include Alcon P140 (manufactured by Arakawa Chemical Co., Ltd.), Clearon M105 (manufactured by Yasuhara Chemical Co., Ltd.), Escoletz E5320 (manufactured by Exxon Chemical Co., Ltd.), and softening points thereof. There are different grades.

The composition of the adhesive is basically a mixture of the hydrogenated block copolymer and hydrogenated petroleum resin or hydrogenated terpene resin.
Known additives such as a softening agent, a deterioration preventing agent, an ultraviolet absorber, a filler, and the like, which are compounded with an adhesive, are appropriately added thereto depending on the application.

The amount of the hydrogenated petroleum resin or the hydrogenated terpene resin compounded is 10 to 200 parts by weight, more preferably 50 to 150 parts by weight, based on 100 parts by weight of the hydrogenated block copolymer. . This compounded amount is 1
If the amount is less than 0 parts by weight, the adhesive strength will be low, and if the amount is more than 200 parts by weight, the adhesive will be too hard, and sufficient adhesiveness will not be exhibited or the heat-resistant adhesiveness will be poor.

To produce the adhesive tape according to the present invention,
For example, a base material sheet made of a polypropylene-based resin which has been formed into a sheet shape in advance, the adhesive is applied with a solution and dried, or the adhesive is applied onto a release paper with a solution and dried,
The formed pressure-sensitive adhesive layer is laminated on a base sheet made of polypropylene resin. As a particularly preferable method, there is a method of integrally forming the adhesive resin with the base sheet resin by a melt coextrusion method into a tape shape to produce an adhesive tape. In the case of solution coating or laminating,
Although the bond between the base sheet and the pressure-sensitive adhesive layer may not be sufficient, according to the above coextrusion method, since the base sheet and the pressure-sensitive adhesive layer are adhered in a molten state, a strong interlayer adhesive strength between the two is developed. As a result, an adhesive tape exhibiting a performance without delamination can be obtained.

The pressure-sensitive adhesive sheet according to the present invention can be used as a display label, a bonding tape, a packaging tape, etc. for a polypropylene molded article which is an adherend when the pressure-sensitive adhesive layer is formed on only one side of the polypropylene base sheet. . Further, the double-sided pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer is formed on both sides of a polypropylene base sheet can be used not only for fixing members, but also for use as a pressure-sensitive adhesive tape for polypropylene molded products.

[0017]

In the pressure-sensitive adhesive tape according to the present invention, since the pressure-sensitive adhesive is composed of a mixture of a hydrogenated block copolymer and a hydrogenated petroleum resin or a hydrogenated terpene resin, it has a low polarity, Similarly, it has high adhesion to a polypropylene-based molded product having low polarity, and therefore exhibits excellent adhesiveness to a polypropylene-based resin molded product as a target adherend. Further, since the base sheet contains polypropylene resin as the main component, the polypropylene molded body can be regenerated without peeling off the adhesive tape. In addition, due to the presence of the polypropylene-based substrate sheet, this adhesive tape does not cause tape breakage or the like at the time of attachment and has good heat resistance.

Further, since the adhesive tape according to the present invention has a high compatibility with polypropylene, when the adhesive tape is integrally regenerated with a polypropylene-based molded body as an adherend, the resin of the adhesive tape is a polypropylene-based molded body resin. The particles are homogeneously compatible with each other or are dispersed microscopically, so that no foreign matter is generated during the reproduction, which does not adversely affect the quality such as strength and elongation of the regenerated molded body.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 Hydrogenated styrene-butadiene-styrene triblock copolymer (trade name: Kraton G-1650) 10
Petroleum resin hydrogenated to 0 parts by weight (brand name Alcon P
-125) 100 parts by weight of an adhesive, and a polypropylene resin (Sumitomo Chemical Co., Ltd., trade name Nobren FK
145) was supplied to a three-layer coextrusion device to prepare a double-sided pressure-sensitive adhesive tape comprising a polypropylene base sheet (thickness 30 μm) and pressure-sensitive adhesive layers (thickness 50 μm each) on both sides thereof.

The adhesion of the double-sided pressure-sensitive adhesive tape to a polypropylene plate (Nobrene FK145) as an adherend was measured.

Further, as a regenerated test piece, a polypropylene resin (Nobrane FK14) which is a resin of an original adherend is used.
5) 100 parts by weight of the double-sided pressure-sensitive adhesive tape was mixed and mixed at a ratio of 10 parts by weight at 230 ° C., and a recycled polypropylene sheet was prepared using this mixture. The appearance and physical properties of this recycled sheet were measured.

Table 1 shows the measurement results of the adhesiveness of the adhesive tape and the performance of the recycled sheet. For comparison with recycled sheets,
The appearance and physical properties of the original sheet of polypropylene alone are also shown as a reference example.

Example 2 Same as Example 1 except that the hydrogenated styrene-butadiene-styrene triblock copolymer in Example 1 was replaced with hydrogenated styrene-isoprene-styrene triblock copolymer. The adhesiveness of the adhesive tape and the performance of the recycled sheet were measured by the method described above. Table 1 shows the measurement results
Shown in.

Example 3 In the same manner as in Example 2 except that the hydrogenated petroleum resin in Example 2 was replaced with a hydrogenated terpene resin (Clearon M105), the tackiness of the adhesive tape and the performance of the recycled sheet were measured. Was measured. The measurement results are shown in Table 1.

Example 4 A pressure-sensitive adhesive tape was prepared in the same manner as in Example 1 except that a polypropylene / polyethylene elastomer blend (manufactured by Highmont, trade name PROFAX KS-011) was used in place of the polypropylene resin in Example 1. The tackiness and the performance of the recycled sheet were measured. The measurement results are shown in Table 1.

Comparative Example 1 Styrene-isoprene-styrene triblock copolymer which was hydrogenated in Example 2 was styrene-isoprene-styrene triblock copolymer which was not hydrogenated (Crayton D1107 manufactured by Shell Chemical Co., Ltd.). ) Was used to measure the adhesiveness of the adhesive tape and the performance of the recycled sheet in the same manner as in Example 2. The measurement results are shown in Table 1.

Comparative Example 2 The same as Example 3 except that the hydrogenated terpene resin in Example 3 was replaced with a non-hydrogenated terpene resin (YS Hara Chemical Co., Ltd., trade name YS Resin TO-105). The adhesiveness of the adhesive tape and the performance of the recycled sheet were measured by the method. The measurement results are shown in Table 1.

Comparative Example 3 A polyethylene terephthalate film (thickness: 25 μm) was used in place of the polypropylene resin in Example 1, and the double-sided pressure-sensitive adhesive tape was prepared by laminating the pressure-sensitive adhesive of Example 1 on both sides of the film. In the same manner, the adhesiveness of the adhesive tape and the performance of the recycled sheet were measured.
The measurement results are shown in Table 1.

Performance test of adhesive tape 1) Peel force test Polypropylene plate (30 mm × 80 mm ×) as an adherend
5 mm) was used. A 20-mm-wide adhesive tape test piece in which a polyethylene terephthalate film having a thickness of 25 μm was adhered to one surface of the adherend was applied to the adherend with a 2 kg roller.
It was attached by crimping back and forth. About this test piece JIS Z
A 180-degree peel test was performed according to O237 to measure the change in peel force.

2) Holding power test Adhesive tape was adhered to an adherend by the same operation as described above and JIS was used.
According to ZO237, a holding force test was carried out at 40 ° C. under a load of 1 kg, and the time until the adhesive tape dropped was measured. In this test, the application area was 25 mm × 25 mm.

Physical property test of recycled sheet 1) Appearance: A sheet having a thickness of 60 μm was extruded and
The presence or absence of fish eyes and the like was examined by visual observation.

2) Tensile physical properties: JIS No. 2 dumbbells were prepared by the JIS K 7113 method, and the tensile physical properties were evaluated.

[0034]

[Table 1] As shown in Table 1, it can be seen that the pressure-sensitive adhesive sheets of Comparative Examples 1 and 3 cannot be regenerated because a large number of foreign matters are present in the regenerated sheet, causing an extremely low elongation. Comparative Example 2
Adhesive sheet has low adhesiveness and the adhesiveness between the polypropylene base sheet and the adhesive layer is poor, so it breaks at the interface between the base sheet and the adhesive layer during the holding force test and falls early. To do.

On the other hand, each of the adhesive tapes of Examples 1 to 4 showed high polypropylene adhesiveness and did not substantially deteriorate the physical properties of the recycled sheet, and the adhesive tape was not peeled off from the polypropylene adherend. It can be seen that the polypropylene adherend can be regenerated.

[0036]

EFFECT OF THE INVENTION Since the pressure-sensitive adhesive tape according to the present invention is constructed as described above, it exhibits excellent adhesiveness to the polypropylene-based resin molded body as the adherend and the polypropylene-based molded body is used as the pressure-sensitive adhesive tape. Can be regenerated without stripping.

In the production of the pressure-sensitive adhesive tape according to the present invention, the base sheet resin and the pressure-sensitive adhesive are integrally molded by a melt coextrusion method, so that the base sheet and the pressure-sensitive adhesive layer are adhered in a molten state. It is possible to obtain a pressure-sensitive adhesive tape that exhibits strong interlaminar adhesive strength between them and exerts a performance without delamination.

Claims (2)

[Claims] 1. A base material sheet having a polypropylene-based resin as a main component, and on at least one surface thereof, a compound represented by the general formula A-B-A or A-B (wherein A is a styrene polymer block and B is a butadiene polymer block or Hydrogenated petroleum resin or hydrogenated terpene based on 100 parts by weight of a hydrogenated block copolymer represented by olefin polymer block obtained by hydrogenating isoprene polymer block) An adhesive tape having an adhesive layer formed by mixing 10 to 200 parts by weight of a resin. 2. A method of integrally molding the base sheet resin and the pressure-sensitive adhesive by a melt co-extrusion method when manufacturing the pressure-sensitive adhesive tape according to claim 1.