JPH0214100A - Release paper for adhesive paper - Google Patents

Abstract

PURPOSE:To obtain the title release paper causing no wavy wrinkles even under highly humid conditions by applying a barrier agent on a base paper of specified smoothness containing mechanical pulp and chemi-mechanical pulp followed by providing a release layer thereon. CONSTITUTION:A base paper containing >=20wt.%, based on the whole pulp, of mechanical pulp and chemi-mechanical pulp (pref. highly bleached chemi- thermomechanical pulp) is put to surface finish using e.g., a calendar made up of a metallic roll with its surface temperature >=50 deg.C and elastic rolls to bring the base paper smoothness to >=50sec/10ml. Thence, the resultant base paper is coated or laminated with a barrier agent (e.g., acrylic resin) followed by forming thereon a release layer using a releasant such as a silicone compound, thus obtaining the objective release paper.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to improvement of release paper for adhesive paper, and in particular, to remove wrinkles that tend to occur in adhesive paper under high humidity conditions from the surface of the release paper. It is something to improve.

[Prior art]

The adhesive paper currently in use is mainly constructed by applying a barrier layer to a base paper, applying a release agent such as silicone to a release paper, applying an adhesive to the release paper, and bonding an upper paper to this release paper.

Chemical pulp (hereinafter simply referred to as "CPi") is usually used as a base paper for release paper for constructing such adhesive paper.
100% glassine paper, high-quality paper, etc. are used. However, when glassine paper made of 100% CP is sequentially coated with an fJJM agent and an adhesive, it expands and contracts during the coating and drying process, which causes the adhesive paper to easily curl.

In addition, we use high-quality paper made of 100% CP, and
Adhesive paper that uses a type of release paper that is coated or laminated with a barrier agent that prevents the penetration of f1ll release agent and then coated with a release agent is said to be prone to waviness and wrinkling under high humidity conditions. There are some difficulties.

In addition, as for CP, the pulp yield in the pulp manufacturing process is 40-50%, so from the perspective of effective utilization of pulp resources, mechanical pulp (hereinafter referred to as "car-pulp"), which can be obtained with a high yield of 75-95%, is used. At present, we are at the stage of considering the use of rMPJ) or chemical mechanical pulp (hereinafter simply referred to as rCMPJ) for adhesive paper as well.

Therefore, the present inventors focused on using MP and CMP as base paper for release paper in order to improve the curls and waviness of adhesive paper and to effectively utilize resources.
MP or CMP instead of using 00% or in combination with CP
I have been considering using . However, although the adhesive paper using MP or CMP as the base paper for %lI release abrasive can improve the problems of curls and waviness, on the other hand, it is difficult to peel off compared to adhesive paper when 100% CP is used, and it is also problematic. It was found that there was a problem that it was not uniform, and that the adhesive surface of the top paper after the release paper was removed became uneven, resulting in poor adhesion and poor transfer of stamp ink to the top paper. . Therefore, it has been confirmed that simply using MP or CMP as a base paper for release paper makes it difficult to obtain adhesive paper with satisfactory quality.

Therefore, as a result of a detailed study of the causes of the above-mentioned difficulties, the inventors of the present invention found that when using MP or CMP, the base paper has rigid bundled fiber pieces (undisintegrated fibers in the pulp) that do not exist in CP. ) and rigid fibers, the paper surface has poor smoothness, and it has been found that this smoothness affects the peelability, adhesion, and transferability of printing ink to the top paper. That is, if the surface of the base paper is poor in smoothness, even if a barrier agent is applied or laminated to the base paper to prevent the release agent from penetrating, the amount of coating is usually 5 g/
Since the amount is less than 1 liter, the base paper layer may be partially exposed or the barrier layer may be too thin.

Even if a release agent is applied thereon, the amount of application is even smaller, usually 0.3 to 0.8 g/m, and a uniform release layer cannot be formed on the paper surface. It was confirmed that as a result of applying a release agent there, drying it, and bonding the top paper, the releasability, adhesion, and transferability of printing ink to the top paper deteriorated.

[Problem to be solved by the invention]

The present invention uses CP or CMP in the pulp constituting the base paper for release paper in order to improve the problem of waviness and wrinkles that tend to occur in adhesive paper under high humidity conditions. The object of the present invention is to provide a release paper that improves the problems of poor release properties and printing ink transfer properties that occur in some cases.

[Means to solve the problem]

The present invention was developed based on intensive studies based on the above objectives.
We have developed a release paper for adhesive paper that has the following structure. That is,
The present invention is characterized in that, in a release paper for adhesive paper containing mechanical pulp or chemical mechanical pulp, a base paper having a surface smoothness of 50 seconds/10 m2 or more is used.

(Function) In the above configuration, concrete examples of MP or CMP include ground wood pulp, refiner ground pulp, chem refiner pulp, chem ground pulp, thermomechanical pulp, and chemothermomechanical pulp (hereinafter simply referred to as r
Mechanical pulps such as pressurized ground pulp and the like can be mentioned. Among them, bleached CTMP (hereinafter simply r
BCTM (referred to as B CT M P J) has high whiteness, good light transmittance, strong paper strength, and less binding fibers.
P is preferred. Furthermore, when adhering an adhesive label to an article, the use of a Laherer, which uses a phototube to detect the presence or absence of a label on a release paper by detecting the difference in light transmittance and performs ON/OFF scanning, is widely used. When adhesive labels are used in this way, there must be a difference in light transmittance between the part with the label and the part without the label (only peeled paper).
The release paper will be required to be transparent. However, base paper using MP or CMP generally tends to have a decrease in light transmittance, but only +3 CT M P has a small decrease in light transmittance, so it is suitable for use as a base paper for release paper. It is desirable to use BCTMP as the MP or CMP.

The amount of these pulps to be used is not particularly limited, but in order to bring out the characteristics of these pulps (i.e. prevention of curling and waviness), it is preferably 20% by weight or more of the total pulp constituting the base paper. It is desirable to contain 30% by weight or more.

An important requirement for the release paper base paper for adhesive paper of the present invention is that the surface smoothness of the base paper made from these pulps should be at least a certain level. Incidentally, the surface smoothness of base paper made from normal MP or CMP using a normal long multi-tube cylinder dryer is 20 seconds/10 m! ! The following is
Adhesive paper using this base paper has poor releasability, and furthermore, poor adhesion and transfer of printing ink to the top paper. Therefore, in the present invention, the smoothness of the base paper is set to 50 seconds/10 m 1 or more,
The feature is that a base paper preferably adjusted to 100 seconds/10 mA or more is used. Incidentally, the smoothness of the base paper is 50 seconds/10mj! The reason specified above is 50 seconds/10
m 7! If the barrier agent is applied or laminated, the surface smoothness is poor, and even if a release agent is applied thereon, the surface smoothness of the release layer is also poor, resulting in poor releasability and
This is because the adhesiveness and the transferability of printing ink to the top paper are also poor, resulting in a decrease in the quality of the adhesive paper.

Therefore, in order to obtain a base paper with a base paper smoothness of 50 seconds/10 mJ or higher, the surface temperature of paper made with a normal long multi-tube cylinder dryer must be heated to a surface temperature of 50°C or higher using a valve containing MP or CMP. This is achieved by a calender surface finishing machine consisting of metal rolls and elastic rolls. Calenders made of metal rolls and elastic rolls include super calendars, gross calendars, soft calendars, etc., which are used on-machine or off-machine.

The surface of the metal roll may be mirror-finished with hard chrome plating, etc., and the surface temperature is 50°C or higher, preferably 1.
It is preferable to maintain the temperature at 00°C or higher. Further, as the elastic roll, a resin roll such as polyurethane or polyamide, or a roll formed by molding conoton, asbestos, nylon, aramid fiber, etc., is used as appropriate.

The reason why it is preferable for the temperature of the metal roll to be 50°C or higher is because the bulbs that make up the base paper begin to soften from around 50°C mt, so the smoothness of the paper surface rapidly improves after this temperature. . Therefore, if the temperature of the metal roll is less than 50℃, the smoothness of the base paper will be less than 50 seconds/10m1, and even if a barrier agent is applied or laminated, the surface smoothness will be poor, and a release agent will be applied on top of it. Also, the surface smoothness of the release layer is poor. As a result, the releasability, adhesion, and transferability of printing ink to the top paper are poor, resulting in a deterioration in the quality of the adhesive paper.

Calendar roll pressure conditions are 50 to 500 kg in linear pressure.
/cm, and adjust accordingly.

In addition, in order to obtain a base paper with a base paper smoothness of 50 seconds/10 m1 or more, in addition to finishing with a calendar, it is necessary to use a papermaking method in which a Yanki dryer is used as the dryer when making paper from pulp containing MP or CMP. This is achieved by The surface of the Yankee dryer is mirror-treated with hard chrome plating, etc., and the paper enters the Yankee dryer with a moisture content of 15% to 70% at the entrance of the Yankee dryer, and the paper is dried with it stuck to the mirror surface of the drum. As a result, the mirror surface of the drum is transferred to the paper, the surface of the paper becomes glossy, and paper with a smoothness of 50 seconds/10 mj2 or more is obtained.

Thus, the base paper made so that the surface smoothness of the base paper is 50 seconds/10 m1 is further coated with or laminated with a barrier agent, and is further provided with a release agent layer.

As the barrier agent used, solvent-resistant resins such as polyolefin resins, polyvinyl alcohol, and acrylic resins, or pigment coating liquids are preferably used. These materials are applied by commonly known methods such as roll coaters or extrusion coaters.

In particular, the coating amount is preferably 2 to 5 g/m in terms of dry weight, and the lamination amount is preferably about 7 to 20 microns.

The release agent is not particularly limited (any known release agent such as a silicone compound or a fluorine compound can be used), and the release layer can also be formed according to a conventional method.

The release paper for adhesive paper obtained in this way is chemical valve 1.
Compared to 00% release paper, there are fewer curls and waviness wrinkles, and even though it contains MP or CMP, it has good release properties, adhesion, and transfer of printing ink to the top paper. You can get paper.

Examples of the present invention will be described below, but it goes without saying that the present invention is not limited only to these examples.

In addition, parts in the examples mean parts by weight unless otherwise specified.

Example 1 Freeness 320mj! 30 parts of BCTMP and LBKP
To a pulp suspension consisting of 60 parts and 2500 m7!0 NBKPIO parts of free, talc was added so that the paper component was 8%, and rosin size was added as a sanding agent at 0.3% based on the bone dry pulp. P of this pulp slurry
After adjusting II to 4°5 with a sulfuric acid band, the long paper machine (
Using a multi-tube cylinder dryer), dry an aqueous solution of oxidized starch (Egg Corn Starch ``Ace AJ'') by 2.
While pressing the size so that the weight is 4 g / d, the basis weight is 7.
A paper weighing 4 g/bo was made. Next, this base paper is calendered in a super calender (metal roll temperature: 60°C) consisting of a metal roll and an elastic roll, and the smoothness is 1.
A base paper for release paper of 00 seconds/10 m1 was obtained. Next, polyethylene with a thickness of 14 μm was laminated on this base paper using a film extruder to form a barrier layer, and silicone (RSRX211J manufactured by Silicone ■) was then laminated on the barrier layer.
) 100 copies and Catalyzer (Toshi, made of silicone)
SRX 212 CATI) Dilute 0.6 part with toluene? ; A 5% release agent solution was applied using a bar coater to a dry weight of 0.1 g/ra, and dried to obtain a release paper. In addition, when this release paper was used to construct an adhesive paper, the waviness of the adhesive paper, the weight of peeling, and the ink transferability to the upper paper were as shown in the attached table.

Example 2 Talc was added to a valve suspension consisting of 80 parts of bleached CTMP with a freeness of 320 mJ and 20 parts of NBKP with a freeness of 500 mA so that the paper content was 8%,
As a sizing agent, the rosin size is 0 for absolute dry pulp.
．． Added 3%. After adjusting the pH of this pulp slurry to 4.5 with a sulfuric acid hand, tapioca starch (R
ONL-900J) aqueous solution at a dry weight of 2.4g/
rr? While pressing the size so that it becomes 174g/
Then, this base paper was calendered with a super calender (metal roll temperature 60°C) consisting of a metal roll and an elastic roll, and the smoothness was 60 seconds/
10mj! A base paper for release paper was obtained. Next, this base paper was laminated with polyethylene in the same manner as in Example 1, and a release agent was further applied to obtain a release paper. In addition, when this release paper was used to construct an adhesive paper, the undulations and wrinkles of the adhesive paper, the weight of peeling, and the ink transferability to the upper paper were as shown in the attached table.

Example 3 The long paper machine paper obtained in Example 2 was thermally calendered using a metal roll and an elastic roll (metal roll temperature 110°C).
) to process the calendering and smoothness 120 seconds/10m1
A base paper for release paper was obtained. Next, this base paper was laminated with polyethylene in the same manner as in Example 1, and a release agent was further applied to obtain a release paper. In addition, when this release paper was used to construct an adhesive paper, the undulations and wrinkles of the adhesive paper, the weight of peeling, and the ink transferability to the upper paper were as shown in the attached table.

Example 4 The long paper machine paper obtained in Example 2 was thermally calendered using a metal roll and an elastic roll (metal roll temperature 150°C).
) to process the calendering and smoothness 400 seconds/10m6
A base paper for release paper was obtained. Next, this base paper was laminated with polyethylene in the same manner as in Example 1, and a release agent was further applied thereto to obtain a release paper. In addition, when this release paper is used to compose adhesive paper, the undulations and wrinkles of the adhesive paper,
The weight of peeling and ink transfer to the top paper were as shown in the attached table.

Example 5 Freeness 320ml bleached CTMP 30 parts and FreeX
500m7! LBKP40 part and freeness 550m
Talc was added to the valve suspension consisting of 30 parts of 42NBK'P so that the paper content was 8%, and rosin size was added as a sizing agent at 0.3% based on the bone dry bulb. After adjusting the pH of this pulp slurry to 4.5 with a sulfuric acid hand, it was
fi 50 g/rrr, smoothness 110 seconds/10m
jl! A release paper base paper was obtained.

Next, this base paper was laminated with polyethylene in the same manner as in Example 1, and a release agent was further applied thereto to obtain a release paper. In addition, when this release paper was used to construct an adhesive paper, the undulations and wrinkles of the adhesive paper, the weight of peeling, and the ink transferability to the upper paper were as shown in the attached table.

Comparative Example 1 An adhesive paper was constructed in the same manner as in Example 2, except that the release paper base paper was used as it was without supercalendering. The smoothness of this base paper surface is 15 seconds/10m1
Met.

The waviness of the adhesive paper, the weight of peeling, and the ink transferability to the top paper were as shown in the attached table.

Comparative Example 2 Example 2 except that the calendering process was carried out at a supercalender metal roll temperature of 30°C and the process was bound with release paper base paper.
Adhesive paper was constructed in the same manner. Note that the smoothness of the surface of this base paper was 40 seconds/10 mβ.

The waviness of the adhesive paper, the weight of the release paper, and the ink transferability to the top paper were as shown in the attached table.

Comparative Example 3 An adhesive paper was constructed in the same manner as in Comparative Example 1, except that a valve suspension consisting of 500 m of freeness/100 parts of LBKP was used. The smoothness of this base paper surface is 30 seconds/
It was 10 m 12. The waviness of the adhesive paper, the weight of peeling, and the ink transferability to the top paper were as shown in the attached table.

-Table 1 (Evaluation method) *Label sample punched from undulating wrinkled adhesive paper at relative temperature of 90%
The waviness of the label was visually observed and determined after being left in this environment for 3 hours.

■......Almost no wrinkles occur.

○: Slight waviness and wrinkles occur.

×... Significant waviness and wrinkles occur.

*Peeling weight tensile tester (conditions: peel width 5cm, peeling angle 180°C,
When peeled at a tensile speed of 30 cm/min)? M.I.F.
A1 resistance force (g 15 cm width) was measured.

(The larger the number, the heavier the peeling force.) *Printing is performed using an ink transferable Gearlass Q-33 type printing machine (made in Switzerland).

(Printing ink Dainippon Ink G cAps-c4) ◎・
...Almost no uneven transfer occurs.

○... Slightly uneven transfer.

×...The transfer is quite uneven.

"Effect" The release paper for adhesive paper of the present invention has a surface smoothness of 50 seconds/10 m even if the base paper contains MP or CMP.
By adjusting it to 1 or higher and using it, peeling weight and ink transferability were improved. Furthermore, CI”1
Compared to those using 00% base paper for release paper, the peel weight and ink transfer properties were the same or higher, and adhesive paper with better waviness and wrinkles was obtained. .

Claims (2)

[Claims] (1) In a release paper for adhesive paper coated or laminated with a barrier agent and further provided with a release agent layer, the base paper of the release paper is at least 20% mechanical pulp and/or
or contains chemi-mechanical pulp, and has smoothness (JI
A release paper for adhesive paper, characterized in that SP8119) is 50 seconds/10 ml or more. (2) The release paper according to claim 1, wherein the chemi-mechanical pulp is bleached chemi-thermomechanical pulp.