JP3527800B2 - Adhesive tape - Google Patents

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, and more particularly to a pressure-sensitive adhesive tape for packaging using a plastic film as a base material. When shipping corrugated cardboard boxes etc.
The present invention relates to an adhesive tape capable of preventing load collapse due to slipperiness on the back surface of the adhesive tape, printing on the back surface of the tape, and stabilizing the force required at the time of rewinding the tape.

[0002]

2. Description of the Related Art Generally, an adhesive tape is provided in a state that an adhesive layer is formed on one surface of a base material and wound around a winding core, etc. For the sake of simplicity, a release agent layer of silicone type or long chain alkyl type is provided on the back surface of the tape.

On the other hand, as an adhesive tape for packaging, which is often used for sealing cardboard boxes, a plastic film is used as a base material, an adhesive layer is provided on one surface of the base material, and a release agent layer is provided on the other surface. There is something.

Also in the above-mentioned packaging adhesive tape having a plastic film as a base material, a long-chain alkyl type release agent or a silicone type release agent is used in the release agent layer. When an alkyl-based mold release agent is used, a peeling noise is generated during rewinding, and at the packing site where a large amount of such tape is used, the sound when rewinding the tape becomes extremely loud and the working environment deteriorates. At the same time, the force required to rewind the tape from the winding body (hereinafter referred to as the rewinding force) is increased, and the work efficiency is significantly reduced.

On the other hand, when a silicone-based releasing agent is used as the release agent, it is possible to prevent the occurrence of the peeling noise at the time of rewinding as described above, but the rewinding force becomes too small and the tape is unnecessarily removed. There was a problem in work such as rewinding or when using an automatic laminating machine, the tape did not cut smoothly when cutting the tape. Also, since the back surface of the tape (the surface of the release agent layer) has a small coefficient of kinetic friction, it is slippery, and when the corrugated cardboard boxes to which the tapes are attached are stacked and transported, the load collapse easily occurs.
Further, there is a problem that the surface of the release agent layer cannot be written with an oil-based ink or the like.

As described above, the conventional release agents have their respective disadvantages, and no adhesive tape has been found that solves all the above problems caused by the release agents.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and suppresses the generation of peeling noise when the adhesive tape is rewound from the adhesive tape winding body, and the adhesive tape is attached. When transporting stacked cardboard boxes, etc., it is difficult for the cargo to collapse due to the slipperiness of the back of the adhesive tape (release agent layer surface), and the release agent layer surface can be written on. The present invention provides a pressure-sensitive adhesive tape having an appropriate rewinding force capable of smoothly performing a laminating operation.

[0008]

As a result of intensive studies to solve the above problems, the present inventors have found that in a pressure-sensitive adhesive tape in which a rubber-based pressure-sensitive adhesive is applied to one side of a plastic film substrate As a release agent layer to be provided, it was found that a pressure-sensitive adhesive tape that solves the above problems can be obtained by applying a specific silicone-based release agent having the following composition containing a cellulose derivative, and the present invention has been completed. It is a thing.

That is, the pressure-sensitive adhesive tape of the present invention has a rubber-based pressure-sensitive adhesive layer on one side of a plastic film substrate and the other side,
(A) A separation consisting of 5 to 25 parts by weight of a cellulose derivative (b) and (c) a curing catalyst, based on 100 parts by weight of a diorganopolysiloxane capped with a silanol group at the molecular end represented by the following general formula (1). The above-mentioned problem is solved by the provision of the mold agent layer.

[0010]

[Chemical 2]

In the above construction, the sound pressure level of the peeling sound (A) generated when the adhesive tape winding body is rewound at a speed of 30 m / min is 85 dB or less, and (B) the release agent layer. When the dynamic friction coefficient between the surfaces is 0.20 or more, (C) the release agent layer surface has printability with an oil-based ink, and (D) the adhesive tape winding body is rewound at a speed of 30 m / min. The unwinding force is 400 to 1000 g / 50 mm.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The diorganopolysiloxane capped with a silanol group at the molecular end as the component a) used as a release agent for the pressure-sensitive adhesive tape of the present invention undergoes a condensation reaction and cures due to the catalytic action of the component c). It forms a film and is represented by the following general formula (1).

[0013]

[Chemical 3]

In the above formula (1), R ¹ and R ² are an alkyl group such as a methyl group or an ethyl group, a methoxy group,
Examples thereof include an alkoxy group such as an ethoxy group and a phenyl group. Then, in order to improve the compatibility between the cellulose derivative and the diorganopolysiloxane, a phenyl group is introduced as an essential component in a part of R ¹ and R ² . The content of the phenyl group varies depending on the type of the cellulose derivative used. For example, when ethyl cellulose is used, the content of the phenyl group in R ¹ and R ² is 5 to 5.
10 mol% is preferable, and by using a diorganopolysiloxane whose phenyl group content is adjusted to this range, the compatibility with ethyl cellulose can be improved and the releasability at the time of forming a cured film is improved. It can be compatible. That is, if the content of the phenyl group is less than 5 mol%, the compatibility with the cellulose derivative becomes poor,
If it is more than 10 mol%, the releasability of the cured film will be poor.

The cellulose derivative as the component b) of the present invention is used for adjusting the dynamic friction coefficient of the release agent layer and imparting printability to the release agent layer. Cellulose derivatives such as ethyl cellulose and acetyl cellulose can be used as appropriate.

The amount of the above-mentioned cellulose derivative added is 5 to 25 parts by weight, preferably 7 to 22 parts by weight, based on 100 parts by weight of the silanol group-blocked diorganopolysiloxane containing the component a).

If the amount of cellulose added is less than the predetermined amount, it becomes impossible to impart printability to the surface of the release agent layer and to obtain a dynamic friction coefficient necessary for preventing load collapse. When the amount of the cellulose derivative added is a predetermined amount or more, the film strength of the release agent layer becomes weak and the adhesion to the plastic film as the base material deteriorates, and the release agent falls off from the base material (friction, etc.). It is easily peeled off) and cannot be practically used.

Such a cellulose derivative may be blended alone in the condensation reaction type silicone composition and mixed, but in order to enhance the mixing efficiency, a form in which the cellulose derivative is previously dispersed in the silicone polymer is used. Good.

As the curing catalyst as the component c) of the present invention, those conventionally used as condensation reaction type silicone catalysts can be appropriately selected and used, and examples thereof include dibutyltin dilaurate and dibutyltin diamine. Examples include acetate, dibutyltin dioctate, and zinc octylate.

The above-mentioned component c) is added in a necessary amount according to the curing characteristics of the silanol group-blocked diorganopolysiloxane having a molecular terminal and the adhesion to the substrate.

Further, in order to sufficiently cure the diorganopolysiloxane endblocked with the silanol group at the molecular end which is the component a), an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule is used. It can be blended appropriately.

Further, as the release agent composition, three-dimensional organopolysiloxane may be appropriately blended in order to make the surface of the release agent layer less slippery (to increase the dynamic friction coefficient).

In the pressure-sensitive adhesive tape of the present invention, a plastic film substrate is provided with a rubber-based pressure-sensitive adhesive layer on one side and a release agent layer made of a condensation reaction type silicone composition containing a cellulose derivative on the other side. In selecting each material of the condensation reaction type silicone composition in which the film base material, the rubber-based pressure-sensitive adhesive, and the cellulose derivative are mixed, the pressure-sensitive adhesive tape having the above-mentioned configuration is measured according to the measuring method described below. It must be designed to satisfy the characteristics.

That is, (A) the adhesive tape winding body
The sound pressure level of the peeling sound generated when rewound at a speed of 0 m / min is 85 dB or less, preferably 80 dB or less. If the sound pressure level of the peeling sound is higher than 85 dB, the peeling sound generated at the time of rewinding the adhesive tape becomes large, and it becomes a cause of deteriorating the working environment particularly at a packing site where a large amount of the adhesive tape is used.

(B) The coefficient of dynamic friction between the surfaces of the release agent layers is 0.20 or more, preferably 0.25 to 0.5. If the dynamic friction coefficient is smaller than 0.20, the back surface of the adhesive tape (release agent layer surface) will be slippery, and the cargo will collapse when the cardboard boxes and the like with the adhesive tape attached are stacked and transported. It will be easier.

(C) The surface of the release agent layer has printability with an oil-based ink.

(D) Adhesive tape winding body, 30m / min
Unwinding force when rewinding at the speed of 400-100
It is 0 g / 50 mm, preferably 500 to 900 g / 50 mm. If the unwinding force is less than 400g / 50mm,
There are problems such as the tape being unwound more than necessary when the adhesive tape is rewound, and the tape is not cut smoothly when the tape is cut when using an automatic laminating machine. Further, if it exceeds 1000 g / 50 mm, a large force is required for rewinding the pressure-sensitive adhesive tape, which causes a significant decrease in work efficiency.

In the present invention, the release agent composition of the above a) to c) is diluted with a solvent such as toluene, ethyl acetate, hexane or heptane, and then a smoothing bar, a gravure coater, an offset coater or the like is used. Applied to a plastic film substrate. The coating amount of the release agent layer formed on the plastic film substrate after drying is usually 0.
05-0.50 g / m ² , preferably 0.1-0.3 g
/ M ² .

As the plastic film used as the adhesive tape base material of the present invention, for example, nylon, polyethylene, polyvinyl chloride, polyester, polypropylene, etc. which have been conventionally used as the adhesive tape base material are appropriately used. Although it is not particularly limited, it is more preferable to use oriented polypropylene (O
PP) film.

The thickness of the substrate is usually 12 to 100 μm,
It is preferably 25 to 60 μm.

The rubber-based pressure-sensitive adhesive used in the pressure-sensitive adhesive tape of the present invention, for example, when used as a pressure-sensitive adhesive tape for packaging, satisfies the pressure-sensitive adhesive properties of the pressure-sensitive adhesive tape for packaging and has a plastic film base. In the case of a pressure-sensitive adhesive tape composed of a release agent layer made of a condensation reaction type silicone composition in which a material and cellulose are blended, it is particularly limited as long as it satisfies the characteristics (A) to (D) described above. However, synthetic rubber such as natural rubber adhesive, ABA type or AB type block copolymer (A is a thermoplastic block, B is a rubber block, for example, styrene-isoprene-styrene copolymer) Examples of the pressure-sensitive adhesives include natural rubber-based pressure-sensitive adhesives, in order to satisfy various required properties as a pressure-sensitive adhesive tape for packaging.

The thickness of the adhesive applied to the plastic film substrate is usually 15 to 60 μm, preferably 25.
Is about 45 μm.

The method for producing the pressure-sensitive adhesive tape of the present invention may be any known method and is not particularly limited. For example, after applying the release agent to one surface of the plastic film, the release agent is cured in a heat oven. Examples of the method include a method in which a pressure sensitive adhesive is applied to the opposite surface of the plastic film, dried in a hot oven, and then wound on a winding core.

[0034]

EXAMPLES Next, the adhesive tape of the present invention will be described in more detail based on examples, but the present invention is not limited thereto. In addition, all the parts described below represent parts by weight.

Example 1 As a mold release agent, (a) polydimethylsiloxane: polymethoxysiloxane: polydiphenylsiloxane (molar ratio = 11: 1: 1.3), a silanol group-terminated diorganopolysiloxane having a molecular terminal silanol group (commercial product) Name: KS-723
B, solid content 45%, manufactured by Shin-Etsu Chemical Co., Ltd.) 70 parts, (b)
Ethylcellulose-containing polysiloxane consisting of ethylcellulose: polymethoxysiloxane: polybutoxysiloxane (molar ratio = 2.4: 2: 1) (trade name: KS-7
23A, solid content 20%, manufactured by Shin-Etsu Chemical Co., Ltd.) 30 parts,
(C) 4 parts of tin-based curing catalyst (trade name: PS-3, manufactured by Shin-Etsu Chemical Co., Ltd.), dimethylhydrogen polysiloxane (trade name: X-92-122, solid content 30%: manufactured by Shin-Etsu Chemical Co., Ltd.) 4 parts were mixed in toluene to obtain a solid concentration of 1.
A condensation reaction type silicone release agent having a concentration of 5% was prepared.
(The amount of ethyl cellulose was 7.6 parts by weight based on 100 parts by weight of the silanol group-blocked diorganopolysiloxane blocked by the molecular end of this release agent. The amount was 9 mol%.) The condensation reaction type release agent treatment liquid was smoothed on one surface of an OPP film having a thickness of 40 μm so that the coating amount after drying was 0.2 g / m ^2. It was applied with a bar and dried at 100 ° C. for 2 minutes to form a release agent layer. As a rubber adhesive, (1) 100 parts of natural rubber (trade name: SMR, manufactured by Kasho Co., Ltd.), (2) 90 parts of petroleum-based resin (trade name: Quinton D-100, manufactured by Zeon Corporation), ( 3) Terpene phenol resin (trade name:
PR-12603N, manufactured by Sumitomo Chemical Co., Ltd.) 10 parts,
(4) 2 parts of an antiaging agent (Sumilyzer NW: manufactured by Sumitomo Chemical Co., Ltd.) was mixed in toluene to prepare a rubber-based adhesive having a solid content concentration of 20%. The above rubber-based pressure-sensitive adhesive is applied to the opposite surface of the OPP film coated with the release agent with a reverse coater and dried in a drying oven at 100 ° C. for 2 minutes to give a rubber-based pressure-sensitive adhesive having a thickness of 40 μm. After forming the layer, it was wound on a cylindrical winding core to obtain an adhesive tape of the present invention.

Example 2 Adhesion was the same as in Example 1 except that the silanol group-blocked diorganopolysiloxane KS-723B was changed to 60 parts and the ethylcellulose-containing polysiloxane KS-723A was changed to 40 parts. A tape was made. (The amount of ethyl cellulose was 11.2 parts by weight based on 100 parts by weight of the silanol group-blocked diorganopolysiloxane of the release agent. Also, the phenyl group content in the diorganopolysiloxane blocked by the silanol groups of the molecule end was The amount was 8.6 mol%.)

Example 3 Adhesion was the same as in Example 1 except that the amount of silanol group-blocked diorganopolysiloxane KS-723B blocked at the molecular end was changed to 50 parts and that of ethylcellulose-containing polysiloxane KS-723A was changed to 50 parts. A tape was made. (The amount of ethyl cellulose was 15.7 parts by weight based on 100 parts by weight of the silanol group-blocked diorganopolysiloxane of the release agent. In addition, the phenyl group content in the silanol group-blocked diorganopolysiloxane of the molecule end was measured. The amount was 8 mol%.)

Example 4 Adhesion was the same as in Example 1 except that the silanol group-terminated diorganopolysiloxane KS-723B was changed to 40 parts and the ethylcellulose-containing polysiloxane KS-723A was changed to 60 parts. A tape was made. (The compounding amount of ethyl cellulose was 21.4 parts by weight based on 100 parts by weight of silanol group-blocked diorganopolysiloxane of the release agent. In addition, the phenyl group content in the silanol group-blocked diorganopolysiloxane of molecule end was contained. The amount was 7.3 mol%.)

Comparative Example 1 Adhesion was the same as in Example 1 except that the silanol group-terminated diorganopolysiloxane KS-723B was changed to 10 parts and the ethylcellulose-containing polysiloxane KS-723A was changed to 90 parts. A tape was made. (The amount of ethyl cellulose blended was 44.4 parts by weight based on 100 parts by weight of silanol group-blocked diorganopolysiloxane of the release agent. In addition, phenyl group-containing diorganopolysiloxane blocked by silanol groups of molecule end was used. The amount was 2.5 mol%.)

Comparative Example 2 Adhesion was the same as in Example 1 except that the diorganopolysiloxane KS-723B blocked with a silanol group at the molecular end was changed to 90 parts and the polysiloxane KS-723A containing ethylcellulose was changed to 10 parts. A tape was made. (The amount of ethyl cellulose blended was 2.1 parts by weight based on 100 parts by weight of the silanol group-blocked diorganopolysiloxane of the releasing agent. In addition, the phenyl group content in the silanol group-blocked diorganopolysiloxane of the molecule end was The amount was 9.7 mol%.)

Comparative Example 3 An adhesive tape was produced in the same manner as in Example 1 except that the adhesive in Example 3 was changed from a rubber adhesive to an acrylic adhesive having the composition shown below. Here, as the acrylic adhesive, 2-ethylhexyl acrylate 1
Acrylic ester copolymer consisting of 00 parts and 3 parts of acrylic acid (number average molecular weight of about 500,000, solid content of 30%) to 3 parts of isocyanate-based crosslinking agent (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) The one having the following composition was used.

Comparative Example 4 In Example 1, the release agent was changed from a condensation reaction type silicone composition containing ethyl cellulose to a long-chain alkyl type release agent (trade name: Pyrroyl 1010, manufactured by Kyodosha Yushi Co., Ltd.). Except that the 0.5% toluene solution of
An adhesive tape was produced in the same manner as in Example 1.

Table 1 shows the results of examining the following characteristics of the pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples.

1) Sound Pressure Level The sound pressure level at the time of rewinding the adhesive tape generated under the following conditions was measured at a distance of 1 m from the sound source using an integral precision sound level meter. Using a high-speed rewinding tester, a 50 mm wide adhesive tape roll was measured for sound pressure generated when it was rewound at a speed of 30 m / min. At this time, the surrounding sound pressure level (blank value) was 30 dB.

2) Dynamic Friction Coefficient As shown in FIG. 2, an adhesive tape 5a is attached to the support 4 with the release agent layer on the upper surface, and the adhesive tape 5b cut into a size of 40 mm × 40 mm is released. The agent layer is placed on the lower side and brought into contact with the release agent layer of the adhesive tape 5a. Adhesive tape 5b
A corrugated cardboard paper 6 of the same size as the adhesive tape 5b is attached to the adhesive surface of, and a load 7 of 1 kg is placed on it, and the adhesive tape 5b is 500 mm / min using a tensile tester.
The resistance value when the surface of the release agent layer of the adhesive tape 5a was moved was read at the pulling speed of, and the dynamic friction coefficient was calculated by the following formula. (Measurement was performed in an atmosphere of 20 ° C.)

[0046]

[Equation 1]

3) Printability Using a commercially available oil-based ink pen, write a character on the surface of the release agent layer of the pressure-sensitive adhesive tape, ⊚ when there is no repelling of the oil-based ink, ◯ when there is almost no repelling of the oil-based ink, and ink The case where there is a small amount of repellency was evaluated as Δ, and the case where the repellency of the ink was remarkable was evaluated as x.

4) Tape rewinding force A tape rewinding force of 50 mm width was measured using a high-speed rewinding tester at a speed of 30 m / min.

5) Release agent adhesion When the surface of the release agent layer of the pressure-sensitive adhesive tape fixed on the glass plate with the pressure-sensitive adhesive side facing downward was rubbed 5 times with the index finger, the release agent was scarcely dropped off. ○: A little release agent was dropped off △: A release agent was noticeably dropped off ×
Evaluated as.

[0050]

[Table 1]

[0051]

The pressure-sensitive adhesive tape of the present invention has a release agent layer made of a condensation reaction type silicone composition in which a rubber-based pressure-sensitive adhesive is blended on one side of a plastic film substrate and a specific amount of a cellulose derivative is blended on the opposite side. By providing the tape, the noise generated at the time of rewinding the adhesive tape winding body is reduced, and when transporting a cardboard box or the like to which the adhesive tape is attached, it is caused by the slipperiness of the back surface of the adhesive tape (release agent layer surface). Prevents collapse of the load and enables printing on the surface of the release agent layer, and
The force required for rewinding the tape can be stabilized. Therefore, when the adhesive tape of the present invention is used as an adhesive tape for packaging, for example, it is possible to prevent the occurrence of a peeling noise at the time of rewinding the adhesive tape, which is a problem in the past, and at the same time, it is possible to perform a bonding workability. It is possible to provide an improved product to the market.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an adhesive tape of the present invention.

FIG. 2 is a schematic diagram showing a method of measuring a dynamic friction coefficient.

[Explanation of symbols]

1 Release agent layer 2 plastic film substrate 3 Rubber adhesive layer 4 support 5a adhesive tape 5b adhesive tape 6 Corrugated paper 7 load

Front Page Continuation (72) Inventor Masao Kusumoto 1-2-1, Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation (56) References JP 60-1899 (JP, A) Ken Hobo, Adhesive Utilization Note, Industrial Research Institute Co., Ltd., June 20, 1991, 2nd edition of the first edition, p10, 128-131 (58) Fields investigated (Int.Cl. ⁷ , DB name) C09J 7/02

Claims (2)

(57) [Claims] 1. A rubber-based pressure-sensitive adhesive layer on one side of a plastic film substrate made of stretched polypropylene and (a) on the other side.
With respect to 100 parts by weight of a diorganopolysiloxane capped with a silanol group at the molecular end represented by the following general formula (1),
An adhesive tape provided with a release agent layer comprising (b) 5 to 25 parts by weight of a cellulose derivative and (c) a curing catalyst. [Chemical 1] 2. The following (A), (B), (C) and (D)
The pressure-sensitive adhesive tape according to claim 1, which has the following characteristics. (A) The sound pressure level of the peeling sound generated when the adhesive tape winding body is rewound at a speed of 30 m / min is 85 dB or less. (B) The coefficient of dynamic friction between the surfaces of the release agent layers is 0.20 or more. (C) The surface of the release agent layer has printability with an oil-based ink. (D) The rewinding force when rewinding the adhesive tape roll at a speed of 30 m / min is 400 to 1000 g / 50 m.
m.