JP2012144593A - Pressure-sensitive adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive tape less liable to cause defects such as peeling and tearing in wide-temperature environments from a low temperature to a high temperature even when stuck to a thick corrugated board case used for packing heavy goods or to a corrugated board which covers or packs articles in various shapes.SOLUTION: The pressure-sensitive adhesive tape comprises: a polyolefin substrate of a blend of polypropylene and polyethylene uniaxially oriented in the length direction; a pressure-sensitive adhesive layer disposed on one surface of the polyolefin substrate; and a release agent layer of a long chain alkyl-containing polymer disposed on the other surface. The pressure-sensitive adhesive layer is formed of a rubber-based pressure-sensitive adhesive. The pressure-sensitive adhesive tape has tensile strength in the length direction of 5-50 kN/m and a tensile elongation in the width direction of 200-2,000%.

Description

  The present invention relates to a pressure-sensitive adhesive tape that is suitably used, for example, for packaging a cardboard box.

  As an adhesive tape used when packing a cardboard box or the like, a tape having a base material, an adhesive layer provided on one surface of the base material, and a release agent layer provided on the other surface is frequently used. Yes. Such an adhesive tape includes a craft tape in which a paper-based substrate such as craft paper or stretched paper is used as a substrate. Kraft tape is the most produced and inexpensive of packaging tape, and is easily used mainly for sealing cardboard boxes.

  However, since the kraft tape has a paper base material, the strength is not sufficient. Therefore, it is not suitable for packing thick cardboard boxes used for packing heavy items such as metal and large products among cardboard boxes. That is, in a thick cardboard box, when the flap (cover piece) is folded and the cardboard box is closed and the closed part is sealed with craft tape, the repulsive force that the flap tries to return to the original state (open the cardboard box) The craft tape may be torn or torn.

  On the other hand, there is also a film tape having a base material made of a resin film. Examples of the resin film include a polypropylene film, a polyethylene terephthalate film, a polyethylene film, and a composite film thereof. Such a film-type tape is harder to tear than a kraft tape provided with a paper-type base material.

  As a film-type tape, for example, Patent Document 1 discloses a tape having a base material made of a uniaxially stretched polylene-type film and a pressure-sensitive adhesive layer made of an acrylic emulsion-type pressure-sensitive adhesive formed on one surface thereof through an undercoat layer. Proposed.

JP 2010-254741 A

However, when the film-type tape disclosed in Patent Document 1 is used for sealing a thick cardboard box containing heavy objects, the film system adhered by the above-described repulsive force to return the flap to the original state. In some cases, the tape was peeled off.
In addition, when a product is covered with corrugated cardboard or packed in various forms, depending on the shape of the product to be packed, and then a film-based tape is stuck on it, twisting stress is applied to the film-based tape. In some cases, the film-type tape may tear.
Furthermore, since the film-type tape disclosed in Patent Document 1 has poor adhesiveness at low temperatures, there is also a problem that it is easily peeled off in a low temperature environment.

  The present invention has been made in view of the above circumstances, and even when attached to a thick cardboard box used for packing heavy objects or cardboard that covers or packs articles in various forms. An object of the present invention is to provide a pressure-sensitive adhesive tape that does not easily cause problems such as peeling and tearing under a wide temperature environment from low to high temperatures.

The pressure-sensitive adhesive tape of the present invention is composed of a blend of polypropylene and polyethylene, a polyolefin base material uniaxially stretched in the length direction, a pressure-sensitive adhesive layer provided on one surface of the polyolefin base material, and the other A pressure-sensitive adhesive tape having a release agent layer made of a long-chain alkyl group-containing polymer provided on the surface, wherein the pressure-sensitive adhesive layer is formed of a rubber-based pressure-sensitive adhesive, and the tensile strength in the length direction of the pressure-sensitive adhesive tape is 5 ˜50 kN / m and the tensile elongation in the width direction is 200 to 2000%.
The rubber-based pressure-sensitive adhesive contains a tackifying resin, and the tackifying resin preferably contains a tackifying resin having a softening point of 100 ° C. or lower and a tackifying resin having a softening point of 120 ° C. or higher.

  According to the present invention, a wide range of temperatures from low to high can be obtained, even when attached to a thick cardboard box used for packing heavy objects or cardboard that covers or packs articles in various forms. Under the environment, it is possible to provide an adhesive tape that is less prone to problems such as peeling and tearing.

It is explanatory drawing explaining the method of a box loop test, (a) The perspective view of a cardboard piece, (b) The perspective view of an adhesive tape, (c) The front view which shows a mode that an adhesive tape is stuck on a cardboard piece, ( d) It is a front view which shows the mode after sticking an adhesive tape on a cardboard piece. It is explanatory drawing explaining the method of a transport test (i). It is explanatory drawing explaining the method of a transport test (ii).

Hereinafter, the present invention will be described in detail.
The pressure-sensitive adhesive tape of the present invention comprises a polyolefin base material uniaxially stretched in the length direction, a release agent layer provided on one surface of the polyolefin base material, and a pressure-sensitive adhesive layer provided on the other surface. The tensile strength in the length direction is 5 to 50 kN / m, and the tensile elongation in the width direction is 200 to 2000%.
Here, the length direction of the polyolefin base material means a vertical direction (MD (Machine Direction) direction), and the width direction means a horizontal direction (TD (Transverse Direction) direction).

  When the tensile strength in the length direction is 5 kN / m or more, it is used for tape unwinding, sealing thick cardboard boxes containing heavy objects, and sticking to various forms of cardboard. Even if stretched, it does not break. When it is 50 kN / m or less, it can be easily cut at a desired position by a cutting tool such as a cutter when using an adhesive tape. As for the tensile strength of the length direction of an adhesive tape, 5-30 kN / m is preferable.

  When the tensile elongation in the width direction of the adhesive tape is 200% or more, twisting stress acts on the adhesive tape when it is used for adhering to corrugated cardboard in various forms, and in processes such as cargo handling, storage, and transportation. Even if it is done, it can be easily deformed to relieve stress and the adhesive tape will not float or peel off. When it is 2000% or less, it does not thermally shrink at a high temperature and is excellent in workability during the production process of the adhesive tape. The tensile elongation in the width direction of the adhesive tape is preferably 300 to 1500%.

  The pressure-sensitive adhesive tape preferably has a ratio [(B) / (A)] of more than 20 when the tensile elongation in the length direction is A and the tensile elongation in the width direction is B. Accordingly, even when the twisting stress as described above acts on the adhesive tape, the adhesive tape is less likely to float, peel off, or torn longitudinally along the length direction. Moreover, it is easy to unwind when using an adhesive tape.

Further, when the tensile elongation in the length direction is 10 to 40%, the workability when adhering the adhesive tape such as corrugated cardboard is excellent, the adhesion of the corrugated cardboard to the adhesive tape is well maintained, and the adhesive tape is Excellent workability and operability during production.
In addition, if the tensile strength in the length direction is greater than the tensile strength in the width direction, even when the aforementioned twisting stress is applied to the adhesive tape, it can be easily deformed and the stress can be further relaxed. The tape does not float or peel off.

The tensile strength and the tensile elongation are measured using a tensile tester according to JIS K 7127 (1999). The measurement is performed under the conditions of a measurement width of a sample (adhesive tape): 10 mm, an initial distance between chucks: 100 mm, and a tensile speed: 300 mm / min in a 23 ° C., 50% RH environment. The tensile strength is the strength per unit width when the sample is broken. The tensile elongation is a value obtained by subtracting the initial length of the sample from the length when the sample broke, as a percentage of the initial length of the sample.
In addition, when measuring the tensile strength and tensile elongation rate of the length direction of an adhesive tape, a sample is pulled so that the length direction of an adhesive tape may be met. On the other hand, when measuring the tensile strength and tensile elongation in the width direction of the adhesive tape, the sample is pulled along the width direction of the adhesive tape.

  The pressure-sensitive adhesive tape having a tensile strength in the length direction of 5 to 50 kN / m and a tensile elongation in the width direction of 200 to 2000% is stretched after adopting uniaxial stretching as stretching when obtaining a polyolefin substrate. It can be produced by adjusting the magnification or preparing the composition of the composition constituting the polyolefin-based substrate.

  As a composition constituting the polyolefin base material, a polyolefin base material having an excellent balance between strength and elongation can be formed, and therefore a blend of polypropylene and polyethylene is used. When the ratio of polyethylene in the blend (hereinafter sometimes referred to as PE blend ratio) increases, the elongation of the polyolefin-based substrate tends to increase and the strength tends to decrease. When the PE blend ratio is 2% by mass or more, the tensile elongation in the width direction is easily adjusted to 200 to 2000%, and when it is 10% by mass or less, the tensile strength in the length direction is adjusted to 5 to 50 kN / m. It's easy to do.

  The weight average molecular weight (Mw) of polypropylene is preferably 100,000 to 800,000, and more preferably 20 to 600,000. When the weight molecular weight (Mw) is 100,000 or more, the strength of the polyolefin substrate is excellent, and the tensile strength in the length direction is easily adjusted to 5 to 50 kN / m. If it is 600,000 or less, the elongation of the polyolefin-based substrate can be sufficiently increased by reducing the stretching ratio during uniaxial stretching, and the tensile elongation in the width direction can be easily adjusted to 200 to 2000%.

As the polyethylene, it is possible to use low density polyethylene having a density of about 0.90 to 0.95 g / cm ³ , a copolymer of ethylene and another monomer, etc. This is preferable because it is easy to adjust the tensile elongation of the above to the above range.

  The polyolefin base material is uniaxially stretched in the length direction. Such uniaxial stretching tends to increase the tensile strength in the length direction and the tensile elongation in the width direction. Moreover, when the draw ratio in that case is large, there exists a tendency for the tensile strength of the vertical direction to become larger, and when the draw ratio is small, there exists a tendency for the tensile elongation rate of the width direction to become larger. The draw ratio is preferably 1-8, more preferably 3-7, and even more preferably 4-6. When the draw ratio is in such a range, the tensile strength in the length direction is easily set to 5 to 50 kN / m, and the tensile elongation in the width direction is easily set to 200 to 2000%.

  The thickness of the polyolefin-based substrate is not particularly limited, but is preferably about 30 to 150 μm in terms of easy adjustment of the tensile strength in the longitudinal direction and the tensile elongation in the width direction to the above ranges, cost, and workability. More preferably, it is 50-100 micrometers.

  A pressure-sensitive adhesive layer made of a rubber-based pressure-sensitive adhesive is provided on one surface of the polyolefin-based substrate. A pressure-sensitive adhesive layer made of a rubber-based pressure-sensitive adhesive is excellent in adhesiveness in a low temperature environment. In addition, because of its excellent elasticity (elasticity), adhesive tapes with an adhesive layer made of rubber-based adhesives can be used for sticking to corrugated cardboard in various forms, as well as cargo handling, storage, and transportation. Even if torsional stress is applied in the process, it does not tear or peel off. For example, a pressure-sensitive adhesive layer formed from an acrylic pressure-sensitive adhesive is excellent in cohesiveness (holding property) but is inferior in stretchability (elasticity), and therefore easily peels off due to torsional stress. Moreover, the pressure-sensitive adhesive layer formed from the acrylic pressure-sensitive adhesive has insufficient adhesiveness at low temperatures and is inferior in sealing properties at low temperatures.

  Examples of the rubber-based pressure-sensitive adhesive include an elastomer component composed of at least one kind such as a natural rubber-based pressure-sensitive adhesive and a synthetic rubber-based pressure-sensitive adhesive, and terpene-based resin, rosin-based resin, C5-based resin, C9-based resin, C5 / C9, and the like. And a tackifier resin comprising at least one petroleum resin such as a resin.

  As the tackifier resin, it is preferable to use a tackifier resin having a softening point of 100 ° C. or lower and a tackifier resin having a temperature of 120 ° C. or higher in combination in order to exhibit low-temperature adhesive strength and high-temperature cohesive strength. Further, it is more preferable that 20 to 50% by mass of a tackifying resin having a softening point of 100 ° C. or less and 2 to 10% by mass of a tackifying resin having a temperature of 120 ° C. or more are contained in 100% by mass of the rubber-based adhesive. When the rubber-based adhesive contains a tackifying resin having a softening point of 100 ° C. or lower and a tackifying resin having a softening point of 120 ° C. or higher in such a range, the adhesive strength at low temperature is excellent and the adhesive is good. Excellent cohesiveness provides excellent retention in high temperature environments. Therefore, the pressure-sensitive adhesive tape provided with such a tackifying resin as a pressure-sensitive adhesive can be favorably used in a wide temperature environment of 0 to 40 ° C., for example.

  The rubber-based pressure-sensitive adhesive may be blended with additives such as an oil component, a softening agent, an anti-aging agent, a crosslinking agent, and a pigment as necessary.

The coating amount of the rubber-based pressure-sensitive adhesive can be appropriately set depending on the type of the rubber-based pressure-sensitive adhesive and the application of the pressure-sensitive adhesive tape. For example, in consideration of adhesive physical properties such as economy, adhesive strength, tack, and holding power, 5 to 100 g / m ^2. The degree is preferable, and 10 to 70 g / m ² is more preferable.

  A release agent layer made of a long-chain alkyl group-containing polymer is provided on the other surface of the polyolefin-based substrate. The pressure-sensitive adhesive tape having a release agent layer made of a long-chain alkyl group-containing polymer is preferable because it is not easily peeled off even when the pressure-sensitive adhesive tapes are stacked and pasted. In addition, since the surface on which the release agent layer is formed is difficult to slip, even when corrugated cardboard or the like having an adhesive tape attached thereto is stacked, load collapse due to such slip is unlikely to occur. On the other hand, a release agent layer made of, for example, a silicone release agent is so-called light release and has too strong peelability, so that it is difficult to overlap and the surface on which the release agent layer is formed is slippery. For this reason, when corrugated cardboard or the like with adhesive tapes is stacked, the load collapses easily.

  Examples of the long-chain alkyl group-containing polymer include a polymer of a long-chain alkyl group-containing monomer in which a long-chain alkyl group is introduced into a monomer such as acrylic ester, vinyl ester, vinyl ether, acrylamide, maleic acid derivative, and allyl ester. Polymer, or a copolymer of two or more monomers); a copolymer of the long-chain alkyl group-containing monomer and another functional group-containing monomer. Examples of the long chain alkyl group include straight chain or branched chain having 12 to 22 carbon atoms. Specific examples include long-chain alkyl acrylate polymers, long-chain alkyl vinyl ester polymers, long-chain alkyl vinyl ether polymers, long-chain alkyl acrylamide polymers, polymers of long-chain alkyl derivatives of maleic acid, long-chain alkyl allyl esters. Examples thereof include polymers and copolymers thereof. Furthermore, what introduce | transduced long-chain alkyl group by making it react with polymers, such as PVA and a cellulose, can also be used.

The long chain alkyl group-containing polymer is dissolved in an organic solvent such as toluene, n-hexane, cyclohexane or the like, or applied and dried as a water-dispersible (emulsifying) resin on a polyolefin substrate. The coating amount is preferably 0.1 to 2.0 g / m ^{2 in} terms of solid content.

  The surface of the polyolefin-based substrate may be subjected to corona treatment or anchor treatment for the adhesion and coating properties between the polyolefin-based substrate and the pressure-sensitive adhesive layer or release agent layer. Moreover, the sealing layer may be formed in the surface which forms a release agent layer.

The pressure-sensitive adhesive tape of the present invention can be produced as follows.
First, a film made of a blend of polypropylene and polyethylene is prepared by a T-die extrusion method, an inflation method, a calendar method, or the like. Next, the film is uniaxially stretched in the length direction to produce a polyolefin-based substrate. For stretching, a stretching means such as a known uniaxial stretching machine or tubular stretching machine can be used. At that time, corona treatment or annealing treatment may be performed as necessary. Moreover, 1-8 are preferable, as for a draw ratio, More preferably, it is 3-7, More preferably, it is 4-6.

  Next, a rubber-based adhesive is applied to one surface of the polyolefin-based substrate to form an adhesive layer. Further, a liquid containing a long-chain alkyl group-containing polymer is applied to the other surface and dried to form a release agent layer. Examples of the method for forming these layers include a comma coating method, a reverse coating method, a gravure coating method, a reverse gravure method, a kiss coating method, a knife coating method, a die coating method, a bar coating method, a wire bar method, and a transfer method. .

The adhesive tape described above has a tensile strength in the length direction of 5 to 50 kN / m and an elongation in the width direction of 200 to 2000%. Even when it is stretched, it will not break when it is used for sticking to a corrugated cardboard. Moreover, even when a torsional stress acts on the adhesive tape, it can be easily deformed to relieve the stress, and the adhesive tape does not float or peel off.
Moreover, since the pressure-sensitive adhesive layer is formed from a rubber-based pressure-sensitive adhesive, it has excellent adhesiveness in a low temperature environment. In addition, since rubber-based adhesives are also excellent in elasticity (elasticity), adhesive tapes with an adhesive layer made of rubber-based adhesives can be used for sticking to various forms of cardboard, In the process of storage, transportation, etc., even if torsional stress acts, it will not tear or peel off.
In addition, since the release agent layer is made of a long-chain alkyl group-containing compound, it can be overlaid, and even if cardboard or the like with an adhesive tape attached is stacked, load collapse is unlikely to occur.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these Examples.
In the examples and comparative examples, “parts” and “%” indicate “parts by mass” and “% by mass” based on solid content or active ingredient unless otherwise specified.

[Example 1]
An unstretched film was formed from a blend of polypropylene (weight average molecular weight (Mw): 400,000) and polyethylene (density: 0.92 g / cm ³ ) (PE blend ratio: 7%) by a T-die extrusion method. The unstretched film was uniaxially stretched in the length direction at a stretch ratio of 3 to prepare a polyolefin-based substrate having a thickness of 100 μm.
Next, a solution obtained by dissolving a long-chain alkyl group-containing polymer (long-chain alkyl-pendant polymer, trade name: Pyroyl 1200, manufactured by Otsuka Kogyo Co., Ltd.) in toluene on a single side of the polyolefin-based substrate with a wire bar is uniform. And dried at 100 ° C. for 20 seconds to form a release agent layer. At this time, the coating amount was 0.1 g / m ^{2 in} terms of solid content.
Next, 50 parts of a styrene-isoprene block copolymer (trade name: Quintac 3433N, manufactured by Nippon Zeon Co., Ltd.) as an elastomer component, and a petroleum resin having a softening point of 94 ° C. as a tackifier resin (trade name: DX395, manufactured by Nippon Zeon) 50 parts, 5 parts of petroleum-based resin (trade name: Petol 140HM5, manufactured by Tosoh) with a softening point of 140 ° C., 10 parts of oil component (trade name: Sunpure NX-90, manufactured by Nippon San Oil), anti-aging agent (Product name: Nocrack NS-5, manufactured by Ouchi Shinsei Chemical Co., Ltd.) was mixed to prepare an adhesive composition. Then, the pressure-sensitive adhesive composition is heated and melted, and applied to the opposite surface of the polyolefin base material from the surface on which the release agent layer is provided with a die coater (trade name: Park Coater C-400, manufactured by Yuri Roll Machinery Co., Ltd.). And an adhesive layer was formed. At this time, the coating amount was 50 g / m ² .
Thus, after forming the release agent layer and the pressure-sensitive adhesive layer on the polyolefin-based substrate, winding was performed to obtain the pressure-sensitive adhesive tape of Example 1. Table 1 shows the physical properties of the adhesive tape.

[Example 2]
A polyolefin base material was prepared in the same manner as in Example 1 except that the PE blend ratio, stretch ratio, and thickness of the polyolefin base material were changed as shown in Table 1, and an adhesive tape was prepared using the polyolefin base material. Manufactured. Table 1 shows the physical properties of the adhesive tape.

[Example 3]
A polyolefin base material was prepared in the same manner as in Example 1 except that the PE blend ratio, stretch ratio, and thickness of the polyolefin base material were changed as shown in Table 1, and an adhesive tape was prepared using the polyolefin base material. Manufactured. Table 1 shows the physical properties of the adhesive tape.

[Example 4]
A polyolefin base material was prepared in the same manner as in Example 1 except that the PE blend ratio, stretch ratio, and thickness of the polyolefin base material were changed as shown in Table 1, and an adhesive tape was prepared using the polyolefin base material. Manufactured. Table 1 shows the physical properties of the adhesive tape.

[Example 5]
In the pressure-sensitive adhesive composition, the petroleum resin having a softening point of 94 ° C. (trade name: DX395, manufactured by Nippon Zeon Co., Ltd.) used as the tackifying resin was changed to 20 parts, and the petroleum resin having a softening point of 140 ° C. (trade name: Petol) A pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that 140 HM5 (manufactured by Tosoh Corporation) was changed to 30 parts, and a pressure-sensitive adhesive layer was formed. Table 1 shows the physical properties of the adhesive tape.

[Comparative Example 1]
A polyolefin-based substrate was prepared in the same manner as in Example 1 except that only polypropylene having a weight average molecular weight (Mw) of 600,000 was used instead of the blend, and the draw ratio and thickness shown in Table 1 were used. Subsequently, a release agent layer was formed on one side of the polyolefin-based substrate in the same manner as in Example 1.
Next, as an adhesive composition, 0.5 parts of an epoxy-based crosslinking agent (trade name: E-5C, manufactured by Soken Chemical Co., Ltd.) is added to 100 parts of an acrylic adhesive (trade name: SK-1986H, manufactured by Soken Chemical Co., Ltd.). A pressure-sensitive adhesive layer was formed in the same manner as in Example 1 except that the blended composition was used and applied with a comma coater. Table 1 shows the physical properties of the pressure-sensitive adhesive tape thus produced.

[Comparative Example 2]
Instead of the blend, only polypropylene having a weight average molecular weight (Mw) of 400,000 was used, and biaxially stretched at the stretch ratio shown in Table 1 to obtain the thickness shown in Table 1, and the same as in Example 1. A polyolefin-based substrate was prepared, and an adhesive tape was produced using the polyolefin-based substrate. Table 1 shows the physical properties of the adhesive tape.

[Comparative Example 3]
A polyolefin base material was prepared in the same manner as in Example 1 except that the PE blend ratio, stretch ratio, and thickness of the polyolefin base material were as shown in Table 1, and an adhesive tape was produced using the polyolefin base material. did. Table 1 shows the physical properties of the adhesive tape.

[Comparative Example 4]
An adhesive tape was produced in the same manner as in Example 1 except that a polyethylene terephthalate (PET) film having a thickness of 50 μm was used as the substrate instead of the polyolefin-based substrate. Table 1 shows the physical properties of the adhesive tape.

[Comparative Example 5]
As an adhesive composition, an acrylic adhesive (trade name: BPS-4429, manufactured by Toyo Ink Manufacturing Co., Ltd.) 100 parts and an isocyanate-based crosslinking agent (trade name: BHS-8515, manufactured by Toyo Ink Manufacturing Co., Ltd.) 3 parts A polyolefin-based substrate was formed in the same manner as in Example 3 except that the blended composition was used and applied with a comma coater. Table 1 shows the physical properties of the pressure-sensitive adhesive tape thus produced.

[Comparative Example 6]
A polyolefin-based substrate was prepared in the same manner as in Example 1 except that the PE blend ratio, stretch ratio, and thickness of the polyolefin-based substrate were as shown in Table 1.
And the adhesive tape was manufactured like Example 1 except having formed the adhesive layer similarly to the comparative example 5. Table 1 shows the physical properties of the adhesive tape.

The adhesive tape obtained in each example was subjected to the following measurements and evaluations.
<Tensile strength, tensile elongation>
Using a tensile tester, in accordance with JIS K 7127 (1999), measurement width of sample (adhesive tape): 10 mm, initial distance between chucks: 100 mm, tensile speed 300 mm / min, 23 ° C., 50% RH Tensile tests in the length direction (MD direction) and the width direction (TD direction) were performed under the environment, and the strength (tensile strength) and elongation at break of the adhesive tape were measured. The tensile elongation was calculated from the elongation value.

<Tear strength>
Tear strength Measured according to JIS K 7128-2 (1998) (Elementoff tear method).

<Adhesive strength>
In accordance with JIS Z 0237, an adhesive tape was applied to a SUS plate in an environment of 23 ° C. and 50% RH, and the adhesive strength (N / m) was measured by peeling it 180 degrees.

<Box loop test>
FIG. 1 (a) shows a Class A cardboard having a thickness of 5 mm having a Class A 280 g / m ² liner defined in JIS P 3902 and a Class A 125 g / m ² semi-core defined in JIS P 3904. Thus, a rectangular cardboard piece S having a width W ₁ : 50 mm and a length L ₁ : 200 mm was cut out. Here, the corrugated cardboard piece S was cut out in the direction in which the repeating direction of the semi-core waveform and the length direction coincide. Subsequently, the fold lines 11 and 12 were formed by compressing the cardboard pieces S by applying pressure from one side to 50 mm portions from both ends in the longitudinal direction.
On the other hand, as shown in FIG. 1 (b), the width (TD direction _length) W 2: 25 mm, length (MD direction _length) L 2: sampling the adhesive tape T of 150 mm.
And as shown in FIG.1 (c), the corrugated-cardboard piece S was folded from the folding lines 11 and 12, and the adhesive tape T was affixed so that the folded corrugated-cardboard piece S might be wrapped. After that, a 500 g crimping roll (not shown) was rolled back and forth on the adhesive tape T, and the adhesive tape T was crimped to the cardboard piece S.
Immediately after the crimping, as shown in FIG. 1 (d), the cut lines 21 and 22 were made with respect to the adhesive tape T at a portion 25 mm inward from the positions of both the folding lines 11 and 12. The cut lines 21 and 22 have a depth penetrating from one surface to the other surface of the adhesive tape T, and are formed over the entire width of the adhesive tape T.
Thus, the corrugated-cardboard piece S with the adhesive tape T stuck was left for 3 days, and the state of the adhesive tape T in the portion between the cut line 21 and the cut line 22 was visually evaluated.
In addition, from the crimping | compression-bonding of the adhesive tape T to the corrugated-cardboard piece S to evaluation after 3 days was performed by the following three types of environment (i)-(iii). The evaluation was performed according to the following four criteria.
In addition, a plurality of cardboard pieces S were used for the test for each test environment.

(Test environment)
(I) in an environment at 0 ° C;
(Ii) 23 ° C. × 50% RH environment;
(Iii) 40 ° C. × 20% RH environment;

(Evaluation)
(Double-circle): The adhesive tape T does not peel in all the several cardboard pieces.
○: In some corrugated cardboard pieces, the adhesive tape T is not peeled off but is displaced.
(Triangle | delta): There exists peeling of an adhesive tape about the thing of 10% or less among several cardboard pieces.
X: The adhesive tape is peeled off in all cardboard pieces.

<Transport test>
The transportation test was conducted under the following two conditions (i) and (ii). The evaluation was made according to the following criteria.
(conditions)
(I) As shown in FIG. 2, a Class A 280 g / m ² liner defined in JIS P 3902 and a Class A 5 mm thickness having a Class A 125 g / m ² semi-core defined in JIS P 3904. A 15 kg heavy article was placed in the cardboard box 31, and H was adhered with adhesive tape (width 50 mm) T1 to T6. A transport test was conducted in which the package 30 was transported by 300 km by truck.
In addition, the order which affixes an adhesive tape was affixed on 4 side part T3, T4, T5, and T6 so that it may affix on upper and lower center part T1, T2 first, and may overlap on it.
(Ii) Oyle Interpack Co., Ltd. High Pull Ace (Grade AA700) 10 mm thick, basis weight 1690 g / m ² , 100 mm wide corrugated cardboard, as shown in FIG. 7 mm) 41 was covered and packed from the outside. In the figure, W ₃ is 100 mm and α is 30 °. And in the part which 3 cardboards overlap, adhesive tape T7-T9 was stuck like FIG. In addition, the adhesive tape was stuck also to the lower surface like the upper surface shown in FIG. The adhesive tape is applied at a total of 6 locations. The size of each adhesive tape is 50 mm (width) × 100 mm (length). A transport test for transporting the package 40 packed in this way by a truck for 300 km was performed.

(Evaluation)
A: The adhesive tape does not peel off, float or tear.
○: The adhesive tape is partially lifted, but there is no peeling or tearing.
Δ: There is no peeling or tearing of the adhesive tape, but there is a place where the floating portion is large and the overlapping portion in the cardboard box easily moves.
X: There is a problem such that the cardboard box is opened greatly, or the adhesive tape is peeled off or torn.

Table 1 shows the following.
Comparative Example 1: Since the polyolefin-based substrate was made only of polypropylene, the tensile elongation in the width direction was small, and the results of the transportation test were not good. Moreover, since the pressure-sensitive adhesive layer is acrylic, the results of a box loop test and a transport test at low temperature were not good.
Comparative Example 2: Since the polyolefin base material was made only of polypropylene and was biaxially stretched, the tensile elongation in the width direction was small, and the result of the transport test (ii) was not good. Moreover, since the pressure-sensitive adhesive layer is acrylic, the results of a box loop test and a transport test at low temperature were not good.
Comparative Example 3: Since the draw ratio was large and the PE blend ratio was small, the tensile elongation in the width direction of the polyolefin-based substrate was small, and the results of the transport test (ii) were not good.
Comparative Example 4: The substrate was made of PET, the tensile elongation in the width direction was small, and the result of the transport test (ii) was not good.
Comparative Examples 5 and 6: Since the pressure-sensitive adhesive layer was acrylic, the results of the box loop test and the transport test (ii) at low temperature were not good.

Claims (2)

A polyolefin base material made of a blend of polypropylene and polyethylene, uniaxially stretched in the length direction, an adhesive layer provided on one surface of the polyolefin base material, and a long chain provided on the other surface An adhesive tape having a release agent layer made of an alkyl group-containing polymer,
The pressure-sensitive adhesive layer is formed from a rubber-based pressure-sensitive adhesive,
A pressure-sensitive adhesive tape, wherein the pressure-sensitive adhesive tape has a tensile strength in the length direction of 5 to 50 kN / m and a tensile elongation in the width direction of 200 to 2000%. The rubber-based adhesive contains a tackifying resin,
The pressure-sensitive adhesive tape according to claim 1, wherein the tackifying resin contains a tackifying resin having a softening point of 100 ° C or lower and a tackifying resin having a softening point of 120 ° C or higher.

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