JPS5831116B2 - Manufacturing method of paper adhesive tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention applies a synthetic resin solution having a film-forming ability to seal paper base materials and form a treatment layer. This invention relates to a method for producing a new paper adhesive tape having appropriate peeling and unwinding force and interlayer strength by forming a coating film and applying high viscosity release silicone on the coating surface. It is something.

Various types of adhesive tapes are used as base materials, including plastic, paper, and rubber.
Since it can be easily cut by hand, it is widely preferred for its simplicity.

Among them, kraft paper that has been treated with Kurupak is used as the base material for tapes, as it has considerable strength and can be provided at an extremely low cost, and is therefore widely used, and is said to be the representative base material for packaging paper adhesive tapes. It is becoming more and more popular.

This paper adhesive tape requires a light unwinding force to prevent interlayer destruction of the base material when unwinding the tape.
For this purpose, a silicone release agent is used as a backside treatment agent.

However, in this process, if the peeling ability is too strong, the core of the tape will shift during storage, easily causing the so-called bamboo shoot phenomenon, and when used attached to a tape holder, the rotational inertia of the tape roll will cause the tape to peel more than necessary. This may cause problems in practical use, such as the tape becoming kinked or having to be re-wound.

Therefore, in order to prevent the silicone release agent solution from impregnating the inside of the base paper, the base material of conventional kraft adhesive tapes is made by attaching a hot-melted polyethylene film to one side of the base paper in advance, and applying a silicone release agent onto the film using an organic solvent. The method used is to apply a diluted solution.

However, with this method, since the surface coated with the silicone release agent is smooth, using a normal silicone release agent, only an adhesive tape with an extremely light rewind force of 301/10 mm width or less can be obtained; If the type of release agent, such as a silicone release agent, is changed to make the release property too heavy, the base material often breaks between the eyebrows when the tape is rewound, resulting in a disadvantage that it cannot be put to practical use.

Another method is to impregnate the base material with rubber such as styrene/butadiene rubber or synthetic resin such as polyvinyl alcohol to increase the interlayer strength of the base material, and then apply a silicone release agent on the impregnated film. However, since the silicone-based release agent normally used for removal is used in the form of a low-concentration organic solvent solution of 5% or less, most of it is impregnated into the base material, causing severe damage. It has the disadvantage that it penetrates to the opposite side of the substrate, almost eliminating the peeling effect, and also significantly impairs the anchoring effect of the adhesive applied to the opposite side.

In order to suppress the permeability to such base materials,
A method using a mixed type hard-to-penetrate release agent made by mixing a silicone-based release agent and other substances as in No. 7155 has also been proposed, but if paper adhesive tape manufactured by this method is stored for a long period of time, the silicone-based release agent Possibly due to poor compatibility between the release agent and other substances, phase separation occurs, making it impossible to maintain uniform quality, and the use of large amounts of expensive silicone release agents makes it uneconomical. be.

As a result of intensive research to solve the above-mentioned drawbacks, the present inventors applied a synthetic resin with excellent coating properties to an ordinary paper base material having countless small pores in a coating amount within a range that does not impair the basic physical properties of the base material. (preferably about 1 to tOP/m), it produces very fine surface irregularities and countless pinholes (about 5 to 1000 pinholes/c).
A coating film with a viscosity of 20C was obtained.
By applying a silicone release agent organic solution or silicone oligomer of PS or higher and curing it, the silicone release agent does not penetrate to the opposite side of the base material, and the peeling ability of the coated surface is comparable to that of plastic film. It is possible to reduce the unwinding force to a fraction of that when applied to a smooth surface such as plastic laminated paper, which means that the unwinding force (approximately 35 to 10 S'/10 mm) can be made moderately heavy. This is the heading that led to the present invention.

That is, in the present invention, a porous coating film made of a synthetic resin having film-forming ability is formed on one side of a paper base material, and 20CP is applied on the coating film.
The present invention provides a method for producing a paper adhesive tape, characterized in that a silicone release agent having a viscosity of S or higher is applied, and an adhesive layer is provided on the other side.

According to the manufacturing method of the present invention, the peeling ability can be reduced regardless of the type of silicone release agent applied;
And interlayer failure is extremely unlikely to occur when the base material is peeled off (
This feature is characterized by coating a porous paper base with a synthetic resin (approximately 1 to IOP/m coating amount).
By applying a high viscosity silicone release agent on the surface to form surface irregularities and countless pinholes, and curing it, it has an appropriate rewinding force as an adhesive tape, and it also has the ability to bond between the layers of the paper base material. It is possible to obtain physical properties that do not cause destruction.

As the filter paper base material used in the present invention, kraft paper, Krupak processed paper, Japanese paper, crepe paper, non-woven fabric, etc. are used, and as the synthetic resin with coating film forming ability, it is preferable to use one with good coating properties. Vinyl alcohol, polyvinyl acetate, acrylic resin, etc. are preferably used in either an organic solvent solution system or a latex system.

In addition, as a silicone-based release agent, organic silicone resin-based varnish type or oil type with a viscosity of 20PS is recommended.
As mentioned above, as long as it can be coated with a general equipment preferably at about 30 to 10,000 CPS/30°C, it may be an organic solvent solution type or an oligomer type.

If the viscosity of the silicone release agent is less than 20 CPS, it will not only be impregnated into the paper base material through the numerous pinholes in the porous coating film, making it impossible to obtain a suitable release effect, but also penetrating the paper base material and forming the adhesive layer. This is undesirable because it inhibits the adhesion between the paper base material and the paper base material.

These silicone release agents are applied onto the porous coating film by a conventional method, and then cured by heating or ultraviolet irradiation.

The paper adhesive tape obtained by the production method of the present invention has an appropriate unwinding force, solves interlayer failure of the base material, and has good adhesion between the base material and the adhesive layer. This fact is also clear from the following examples.

Examples and Comparative Examples A polyvinyl alcohol resin solution (PVA) was applied to one side of kraft paper (basis weight 73?/m) at different amounts as shown in Table 1, and dried at 120°C for 3 minutes to form a porous paper. After forming a transparent coating film, a silicone-based release agent was diluted with toluene to make a low-viscosity system (Samples &1.3 and 5) and a high-viscosity system (Sample A2.4). and 6), the amount of silicone applied is about 1 ? / m', then baked and dried at 150° C. for 1 minute, and then a rubber adhesive solution is applied and dried on the opposite side by a conventional method.

Thereafter, it was wound into a roll around a ball core with a diameter of 75 mm and cut into a width of 20 mm to obtain a paper adhesive tape roll.

A commercially available craft adhesive tape was used as sample 7. In order to examine the peelability of the adhesive from the back of each tape roll, each roll was fitted into a light rotating body that rotates with almost no resistance, and the tape was Rewind the end of the roll a little,
The sample was loaded into the chatter of a tension testing machine, and the rotary cylinder was pulled at a speed of 300 mm/min.

At this time, the fitted tape roll was unwound while rotating, and the force required for unwinding was measured using a tension tester.

Furthermore, when the tape roll was held in hand and rewound at an extremely high speed (approximately 60 m/min), it was determined whether or not a fracture occurred between the layers of the base material.

In addition, a qualitative judgment was made as to whether the applied silicone release agent had penetrated to the opposite surface by examining the anchoring ability of the adhesive to the base material.

The results are shown in Table 1. As is clear from Table 1, samples A2.4 and A2.6 coated with a silicone release agent in a high viscosity state did not cause interlayer failure of the base material during tape rewinding. It can be seen that the unwinding force is moderately heavy and the work is extremely easy compared to the case where a silicone release agent is applied on a smooth film without pinholes.

As in samples A1.3 and 5 (if a silicone release agent with a viscosity lower than 20 CPS is used, penetration into the opposite side of the base material is observed, and interlayer failure of the base material may occur when the tape is unwound). It can be seen that this occurs.

Claims (1)

[Claims] 1. A porous coating film made of a synthetic resin with film-forming ability is formed on one side of a paper base material, a silicone release agent with a viscosity of 20 CPS or more is applied on the coating film, and an adhesive layer is formed on the other side. 1. A method for producing a paper adhesive tape, comprising: