JPH03213600A - Release paper for adhesive paper - Google Patents

Abstract

PURPOSE:To obtain the title release paper not causing undulation wrinkle even in exposing tacky paper to a high-humidity condition, yet having excellent release characteristics by using base paper containing regenerated pulp comprising old paper as raw material and having surface smoothness of >= a specific value. CONSTITUTION:Base paper containing >=10wt.%, preferably >=20wt.% based on the whole composition of regenerated pulp (preferably pulp having Canadian standard freeness which can be reduced in a range of 30-150ml by beating treatment in a previous process of paper making machine) and having >=8% measured value of the surface of base paper by regular reflection type smoothness tester under 20kg/cm<2> pressure condition is used to give the objective release paper.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a release paper for adhesive paper, and particularly to a release paper for adhesive paper that does not cause waviness and wrinkles even when exposed to high humidity conditions, and has good releasability. This is a product related to excellent release paper.

``Prior art'' The adhesive paper currently in use is constructed by applying a barrier layer to a base paper, then applying a release agent such as silicone to a release paper, applying an adhesive to it, and then bonding an upper paper to this. Lord.

Chemical pulp (hereinafter simply referred to as "CPj") is usually used as the base paper for the release paper constituting such adhesive paper.
100% glassine paper, high-quality paper, etc. are used. However, glassine paper made of 100% CP has the disadvantage that when a release agent and an adhesive are sequentially applied thereto, expansion and contraction occurs during the coating and drying process, which tends to cause the adhesive paper to curl. In addition, adhesive paper uses a type of release paper that uses high-quality paper made of 100% CP, coats or laminates it with a barrier agent to prevent the penetration of a release agent, and then coats a release agent on top of it. has the disadvantage that under high humidity conditions, undulations and wrinkles are likely to occur.

In addition, CP also has the disadvantage that the pulp yield in the pulp manufacturing process is as low as 40 to 50%.

On the other hand, in recent years, paper, which is included in municipal waste, has received particular attention as well as resource protection. Furthermore, paper generated by households and offices is contributing to an increase in the amount of municipal waste. Therefore, it is desired to collect such waste paper and use it as a raw material.

Therefore, in terms of effective utilization of pulp resources, 75 to 95%
Currently, we are at the stage of considering the use of recycled pulp made from waste paper, which can be obtained at a high yield, even in adhesive paper.

Therefore, the present inventors focused on using recycled pulp made from waste paper as a base paper for release paper in order to improve the curls and waviness of adhesive paper and to effectively utilize resources. We have been considering the use of recycled pulp made from waste paper instead of or in combination with CP.

However, although adhesive paper using a release paper base paper made from recycled pulp made from waste paper can improve the problems of curling and waviness, it is not as good as adhesive paper using a release paper made of 100% CP. The peeling is heavy and uneven.

Furthermore, it was found that when the release paper was removed, the adhesive surface of the paper became uneven, resulting in poor adhesion and poor transfer of printing ink to the top paper. Therefore, it has been confirmed that simply using recycled pulp made from waste paper as a base paper for release paper does not yield adhesive paper that is satisfactory in quality.

Therefore, the present inventors conducted a detailed study on the causes of the above-mentioned difficulties, and found that base paper made from recycled pulp made from waste paper has rigid fibers that do not exist in CP, resulting in a smooth paper surface. It was found that the smoothness affected the releasability, adhesion, and transferability of the printing ink to the top paper.

In other words, if the surface of the base paper is not smooth, even if a barrier agent is applied or laminated to the base paper to prevent the release agent from penetrating, the amount of barrier agent will generally be less than 5 g/M (coating method) or less than 15 microns (depending on the coating method). (Lamination method) and in small quantities, the base paper layer may be partially exposed or the barrier layer may be too thin in some areas.

Even if a release agent is applied on such a barrier layer, the amount of application is even smaller, usually 0.3 to 0.8 g/r+? Therefore, a uniform release layer cannot be formed on the paper surface.

Then, as a result of applying an adhesive to such a release layer and drying it to join the top paper, it is thought that the peelability decreases, and the adhesion and transferability of printing ink to the top paper deteriorates. .

``Problems to be Solved by the Invention'' The present invention provides a method that does not cause waviness and wrinkles even when adhesive paper is exposed to high humidity conditions, has excellent releasability and adhesion, and is capable of removing printing ink from the top paper. The object of the present invention is to provide a release paper for adhesive paper that does not cause transfer defects.

"Means for Solving the Problems" The present invention contains 10% by weight or more of recycled pulp made from waste paper in the total pulp composition, and the measured value with a specular reflection type smoothness meter on the surface of the base paper is under pressure. This is a release paper for adhesive paper characterized by using a base paper having a content of 8% or more under a condition of 20 kg/c+1.

"Function" In the above configuration, specific examples of raw materials for the recycled pulp include kajiro, ruled white, cream kajiro, card, special white,
Examples include medium-white, imitation, colored soil, Ken 1-1 white art, Tokujo-kiri, Betsu-jokiri, Shinkai, magazines, etc. (used paper standard quality specification table: compiled by wJ Kogi Recycling Promotion Center). Recycled pulp is −
Boat fishing involves a disintegration process, a rough selection process, a fine selection process, a deinking process,
It can be obtained by appropriately combining bleaching steps. In the disintegration process, low concentration pulper, high concentration pulper, etc. are used, in the rough selection process and fine selection process, screens, cleaners, etc. are used, and in the deinking process, flotation method, water washing method, compromise method, etc. Selected based on the quality of recycled pulp.

There is no particular limit to the amount of recycled pulp used, but in order to take advantage of the characteristics of these pulps (i.e. prevention of curls and wrinkles), it is necessary to use at least 1% of the total pulp that makes up the base paper.
The content must be 0% by weight or more, preferably 20% by weight or more.

Note that if recycled pulp is blended without treatment, the smoothness of the base paper surface and the paper strength of the base paper may decrease, so it is preferable to treat it with a beating machine in the previous process of the paper machine, and the untreated regenerating valve It is preferable to reduce the Canadian Standard Freeness in the range of about 30 to 150 degrees.

By the way, 30m! If the beating is less than 150 degrees, a sufficient effect of improving the smoothness cannot be obtained, and if the beating is more than 150 degrees, curls and wrinkles may become large.

As the refining machine, a conical refiner, a single disc refiner, a double disc refiner, etc. are used, but in consideration of power, it is more preferable to use a double disc refiner.

An important feature of the present invention is that the surface smoothness of the base paper made from the recycled pulp as described in -1 U is 8% or more as measured by a specular reflection type smoothness meter.

Incidentally, the surface smoothness of base paper obtained by making paper from ordinary recycled pulp using a Fourdrinier multi-tube cylinder dryer is less than 8% as measured by a regular-foul type smoothness meter (pressure condition 20kg/c+M). be.

The specular reflection type smoothness meter referred to here is a device that measures the smoothness of paper by pressing it against a glass surface under constant pressure conditions. It is not affected by the air permeability of the paper, unlike air leak type smoothness measuring instruments such as the Heck smoothness meter and Parker Printserf, and provides measurement values that are highly correlated with actual smoothness. Moreover, this specular reflection type smoothness meter (measurement pressure;
It has become clear that the desired effect of the present invention can be determined very appropriately by the measured values at 20 kg/crM).

By the way, a specular reflection type smoothness meter (pressure condition 20k) on the surface of the base paper was used.
If the measured value in g/cfl) is less than 8%, even if a barrier agent is applied or laminated, the surface smoothness will be poor, and even if a release agent is applied thereon, good smoothness will not be achieved. No release layer can be obtained. As a result, only low-quality adhesive paper is obtained that not only has poor releasability but also insufficient adhesion and transferability of printing ink to the top paper.

Therefore, in the present invention, a base paper is used whose smoothness is adjusted to 8% or more, preferably 16% or more as measured by a specular reflection type smoothness meter (pressure condition 20 kg/cm2).

Therefore, a specular reflection type smoothness meter (pressure condition 20 kg / c
ffl) In order to obtain a base paper with a measured value of 8% or more,
This is accomplished by applying a surface finish to paper made from pulp slurry containing recycled pulp using a conventional Fourdrinier multi-tube cylinder dryer using a calender consisting of metal rolls and elastic rolls. Calenders made of elastic rolls and metal rolls include super calenders, gloss calenders, soft calenders, etc., which are used on-machine or off-machine.

As the elastic roll, a resin roll such as polyurethane or polyamide, or a roll formed by molding cotton, asbestos, nylon, aramid fiber, etc., is used as appropriate.

Further, the surface of the metal roll may be mirror-treated with hard chrome plating or the like, and it is desirable to maintain the surface temperature at 50°C or higher, preferably at λ00°C or higher.

The reason why the temperature of the metal roll is preferably 50°C or higher is because the pulp that makes up the base paper begins to soften around 50°C, and the smoothness of the paper surface improves rapidly at this temperature. It is.

In addition, the pressure condition of the calender roll is 50 to 500 in linear pressure.
It is adjusted appropriately within a range of about kg/cm.

In addition, a specular reflection type smoothness meter (pressure condition 20kg/c + M)
As a method for obtaining base paper with a measured value of 8% or more, in addition to surface finishing with a calendar, it is also possible to adopt a papermaking method in which the dryer used when making paper from pulp containing recycled pulp is a Yankee dryer. Drying with a Yankee dryer is done with wet paper whose moisture content is adjusted to 15-70% attached to the drum surface, which has been mirror-treated with hard chrome plating, etc., so the mirror surface of the drum is transferred to the paper. The surface of the paper is glossy and the measured value with a specular reflection type smoothness meter (pressure condition: 20 kg/crl) is 8% or more.

Then, a specular reflection type smoothness meter (pressure condition 20k) was used for the surface of the base paper.
The base paper produced so that the measured value in g/c*fl) is 8% or more is further coated 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, polyhinyl alcohol, acrylic resins, or pigment coating liquids are preferably used. These materials are applied by generally known methods such as a roll coater or an extrusion coater.

Incidentally, the coating amount is preferably 2 to 5 g/n (dry weight), and the lamination amount is preferably about 7 to 15 microns.

The release agent is not particularly limited, and 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 using recycled pulp made from waste paper obtained in this way has fewer curls and waviness than the release paper for adhesive paper made from 100% chemical pulp, and moreover, it contains recycled pulp. Despite the fact that the surface smoothness of the base paper has exceeded a certain value, it has improved peelability, adhesion, and
A release paper for adhesive paper with good transferability of printing ink to one paper can be obtained.

"Example" The present invention will be described in more detail with reference to Examples below, but it is of course not limited to these.

Note that "parts" and "%" in the examples indicate "parts by weight" and "% by weight," respectively, unless otherwise specified.

Example 1 Regenerated pulp made from newspaper and having a freeness of 240% was refined using a double disc refiner to obtain a freeness of 100ml. 30 parts of this recycled pulp were each beaten to a freeness of 500 mR, B K P 60
Talc was added to the pulp suspension obtained by blending Part and NBKPIO so that the paper ash content was 8%, and a rosin sizing agent was added as a sizing agent at 0.3% based on the bone dry pulp.

After adjusting the pII of this pulp slurry to 4.5 using a sulfuric acid hand, paper was made using a long paper machine (multi-cylinder cylinder 1-layer), and an aqueous solution of oxidized lees yJ (manufactured by clove cornstarch ■ [Ace AJ)] was added to the paper by dry weight. The paper was size pressed to a size of 2.481/mm to obtain a base paper with a basis weight of 74 g/m. Next, the base paper is heated in a super calendar consisting of metal rolls and elastic rolls (metal roll temperature: 60°C).
℃) to obtain a release paper base paper for adhesive paper having a measurement value of 16% using a specular reflection type smoothness meter (pressure condition: 20 kg/cl).

Next, polyethylene with a thickness of 14 μm is laminated on this base paper using a film extruder to form a barrier layer, and silicone (RS made by Silicone) is further applied on the barrier layer.
RX211 J) 100 copies and Catalyzer (East,
0.6 part of Silicone (rSRX212CATJ) was diluted in toluene, and a release agent solution with a concentration of 5% was applied using a bar coater so that the dry weight was 0.7 g/bo, and dried.
A release paper for adhesive paper was obtained.

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 2 Regenerated pulp 32 pulp with a freeness of 40M made from imitation material was refined in a double disc refiner to obtain a freeness of 270M. To 30 parts of this recycled pulp, 60 parts of LBKP and NB beaten to a freeness of 500 mA, respectively.
Talc was added to the valve suspension obtained by blending the KPIO part so that the paper ash content was 8%, and a rosin sizing agent was added as a sizing agent at 0.3% based on the bone dry pulp.
Added.

After adjusting the pH of this pulp slurry to 4.5 with sulfuric acid band, paper was made using a Fourdrinier paper machine (multi-tube cylinder dryer), and tapioca starch (rONL-
An aqueous solution of 900 J) was size-pressed to a dry weight of 2.4 g/rtT to obtain a base paper with a basis weight of 74 g/rff. Next, this base paper was heated in a super calendar consisting of metal rolls and elastic rolls (metal roll temperature 60°C).
) to obtain a release paper base paper for adhesive paper having a measurement value of 10% using a specular reflection type smoothness meter (pressure condition: 20 kg/c+fl).

Next, this base paper was laminated with polyethylene 1-L in the same manner as in Example 1, and a release agent was further applied thereto to obtain a release paper for adhesive paper.

4. When this release paper was used to form an adhesive paper, the undulations and wrinkles of the adhesive paper, the weight of peeling, and the ink transferability to the paper were as shown in the attached table.

Example 3 Freeness 200m made from newspaper, i! The recycled pulp was beaten in a double disc refiner to a 100% freeness. To a pulp suspension obtained by blending 50 parts of this recycled pulp with 50 parts of NBKP beaten to a freeness of 500 mR, talc was added so that the paper ash content was 8%, and a rosin sizing agent was added as a sizing agent to the bone-dry pulp. 0.3% was added.

After adjusting the pI of this pulp slurry to 4.5 with a sulfuric acid band,
A base paper with a basis weight of 74 g/rrf was obtained by size-pressing an aqueous solution of oxidized starch (Ace AJ manufactured by Clove Corn Starch) to a dry weight of 2.4 g/rrf.Next, this base paper was The calendering process was performed using a super calender (metal roll temperature: 60°C) consisting of a metal roll and an elastic roll, and the measured value with a regular irregularity type smoothness meter (pressure condition: 20 kg/c[) was 18%. A release paper base paper for adhesive paper was obtained.

Next, this base paper was laminated with polyethylene 1-L in the same manner as in Example 1, and a release agent was further applied thereto to obtain a release paper for adhesive 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 Recycled pulp with a freeness of 420 ml made from white pulp was refined in a double disc refiner to a freeness of 300 ml. Freeness 5 is added to 90 parts of this recycled pulp.
Talc was added to the pulp suspension obtained by blending the NBKPIO part beaten to zero so that the ash content was 8%, and a rosin sizing agent was added as a sizing agent at 0.3% based on the bone dry pulp. did.

After adjusting the pH of this pulp slurry to 4.5 with sulfuric acid pan 1', a long paper machine (multi-cylinder cylinder dryer)
2.4 g/rrr dry weight of an aqueous solution of oxidized starch (Clove Cornstarch II Kiku [Ace AJ)]
A base paper with a basis weight of 74 g/n was obtained by size pressing. Next, this base paper was subjected to a super calendar consisting of a metal roll and an elastic roll (metal roll temperature: 60").
The calendering process was performed in step C) to obtain a release paper base paper for adhesive paper having a measurement value of 16% using a specular reflection type smoothness meter (pressure condition: 20 kg/cf).

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 for adhesive 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 5 A recycled pulp with a freeness of 500 mR made from white pulp was refined in a double disc refiner to a freeness of 420 m1. To a pulp suspension obtained by blending 80 parts of this recycled pulp with 20 parts of NBKP beaten to Freeness 50 (b++R), talc was added so that the paper ash content was 8%, and further as a sizing agent] 7 to give a rosin size. The agent was added in an amount of 0.3% based on the bone dry pulp.

After adjusting the pH of this pulp slurry to 4.5 with sulfuric acid hunt, paper was made using a long paper machine (multi-tube cylinder dryer), and an aqueous solution of oxidized starch (egg cornstarch 0 grade "Ace AJ") was added to the dry weight of 2. Size pressing was carried out to give a weight of .4 g/rd to obtain a base paper with a weight of 74 g/M.Next, this base paper was subjected to a super calendar consisting of a metal roll and an elastic roll (metal roll temperature: 60°C). The calender was treated and a specular reflection type smoothness meter (pressure condition 2) was applied.
A release paper base paper for adhesive paper having a measured value of 10% at 0 kg/crN) 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 for adhesive paper.

In addition, when this release paper was used to form an adhesive paper, the undulations and wrinkles of the adhesive paper, the weight of peeling, and the ink transferability to the paper were as shown in the attached table.

Example 6 Regenerated pulp with a freeness of 550 mR made from ruled white material was beaten with a double-tice refiner, and the pulp reached 430 mR!
The freeness of To 50 parts of this recycled pulp, 30 parts of LBKP beaten to a freeness of 500%, N
Curku was added to a pulp suspension obtained by blending 20 parts of BKP to give a low ash content of 8%, and a rosin sizing agent was added as a sizing agent at 0.3% based on the bone dry pulp.

After adjusting the pII of this pulp slurry to 4.5 with a sulfuric acid hand, it was made into paper using a Fourdrinier M1 machine (multi-tube cylinder dryer), and an aqueous solution of oxidized starch (“Ace A” manufactured by Clove Corn Starch ■) was added to the paper by dry weight. Size press to make it 2.4g/rd, tsubo! A base paper of t74 g/kidney was obtained. Next, this base paper is subjected to a super calendar consisting of a metal roll and an elastic roll (metal roll temperature: 60°C).
Calender treatment was performed to obtain a release paper base paper for adhesive paper having a measurement value of 30% using a specular reflection type smoothness meter (pressure condition: 20 kg/crR).

Next, this base paper was laminated with polyethylene 1-L in the same manner as in Example 1, and a release agent was further applied thereto to obtain a release paper for adhesive paper.

(2) When this release paper was used to form an adhesive paper, the waviness and wrinkling of the adhesive paper, the weight of peeling, and the ink transferability to the top paper were as shown in the attached table.

Example 7 Paper was made using a long paper machine in the same manner as in Example 2, and the base paper obtained by size pressing was calendered using a thermal calender (metal roll temperature 110'C) consisting of a metal 11-roll and an elastic roll. And specular reflection type smoothness meter (pressure condition 20kg/
A release paper base paper for adhesive paper with a measured value of 19% in crK) 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 for adhesive 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 8 Paper was made using a long-length paper machine in the same manner as in Example 2, and the base paper obtained by Lee's pressing was calendered using a thermal calender (metal roll temperature: 150°C) consisting of a metal roll and an elastic roll. , specular reflection type smoothness meter (pressure condition 20kg/c
A release paper base paper for adhesive paper with a measured value of 64% (nT) 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 for adhesive 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 A release paper for adhesive paper was prepared in the same manner as in Example 2, except that the base paper obtained by paper making with a Fourdrinier paper machine and size pressing was used as a base paper for release paper for adhesive paper without being subjected to supercalender treatment. Got paper.

The smoothness of the surface of this base paper was 3% as measured by a specular reflection type smoothness meter (pressure condition: 20 kg/c+fl). Next, this base paper was laminated with polyethylene 1-L in the same manner as in Example 1, and a release agent was further applied thereto to obtain a release paper for adhesive paper.

In addition, when adhesive paper was made using this Ej1 Riki, the waviness and wrinkling 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 Regenerated pulp made from newspaper and having a freeness of 240 m1 was refined in a double disc refiner to obtain a freeness of 100 m2. To 20 parts of this recycled pulp, 20 parts of LBKP beaten to a freeness of 500 m1, NBK
A release paper for adhesive paper was obtained in the same manner as in Example 2, except that a pulp suspension obtained by blending 60 parts of P was used.

The smoothness of the surface of this base paper was 6% as measured by a specular reflection type smoothness meter (pressure condition: 20 kg/cnT). Next, this base paper was laminated with polyethylene 1-L 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 3 A release paper for adhesive paper was obtained in the same manner as in Example 2, except that a pulp suspension consisting of 100 parts of LBKP beaten to a freeness of 500 vdl was used.

The smoothness of the surface of this base paper was 7% as measured on the specular reflection type smoothness side (pressure condition: 20 kg/cffl).

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 for adhesive paper.

Incidentally, when this release paper was used to form an adhesive paper, the undulations and wrinkles of the adhesive paper, the weight of peeling, and the ink transferability to F paper were as shown in the attached table.

(Evaluation) * Rahel sample punched from wavy and wrinkled adhesive paper at relative humidity of 90%
After being left in the environment for 3 hours, the waviness of the label was visually observed and determined.

"Evaluation criteria" ◎ Almost no wrinkles occur.

○---Slight waviness and wrinkles occur.

×--- Considerable waviness and wrinkles occur.

*Peeling claw 3 tensile tester (conditions: sample width 5 cm, peeling angle 180°
The peel resistance force (g15c+n width) when peeled at a tensile speed of 30 cm/m1n) was measured. (The larger the number, the
Heavy peeling force. ) *Ink transfer properties Printing on top paper was evaluated using a Gearlus Q-33 type printing machine (made in Switzerland). (Printing ink; Dainippon Ink CAPS-G
Can) "Evaluation Criteria" ◎---Almost no transfer unevenness occurs.

o-11--There is slight uneven transfer.

X---There is considerable uneven transfer.

4 Table 5 "Effect" As is clear from the table, the release paper for adhesive paper of the present invention has a specular reflection smoothness value of 8 even though the base paper contains recycled pulp. % or more, the peelability and ink transferability to the top paper were excellent.

Furthermore, even when compared to release paper for adhesive paper made from 100% chemical pulp, the release properties and ink transfer properties are the same or better, and it is also an excellent release paper for adhesive paper that has greatly improved its wrinkling properties. It was paper.

Claims (2)

[Claims] (1) The total pulp composition contains 10% by weight or more of recycled pulp made from waste paper, and the measured value of the base paper surface using a specular reflection type smoothness meter is 8% under a pressure condition of 20 kg/cm^2 A release paper for adhesive paper characterized by using the above base paper. (2) The release paper for adhesive paper according to claim (1), wherein the recycled pulp is pulp whose Canadian Standard freeness has been lowered in the range of 30 to 150 ml by beating treatment in a pre-process of the paper machine.