JPH04209880A - Method for pulping waste release paper - Google Patents

Abstract

PURPOSE:To separate and remove coating layer and releasing agent layer in high efficiency from the subject waste paper having pigment-coating layer and produce reclaimed pulp having high quality by mechanically agitating a specific waste release paper under specific condition, and subjecting the product to flotation treatment, etc. CONSTITUTION:Waste release paper produced by applying a coating layer composed mainly of a pigment and an adhesive to a surface, etc., of a paper substrate and applying a releasing agent layer to a surface, etc., of the coating layer is mechanically agitated at a pulp concentration of >=15% (preferably 20-35%) and >=30 deg.C (preferably 50-90 deg.C) and the product is subjected to flotation treatment and/or cleaner treatment to obtain the objective reclaimed pulp. The mechanical agitation may be performed in the presence of additives such as alkali, acid, penetrate and surfactant.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a method for recycling and pulping waste release paper, and in particular, to extracting a coating layer and a release agent such as silicone from waste paper of release paper having a pigment coating layer. The present invention relates to a method for efficiently separating and removing layers to produce high-quality recycled pulp.

"Prior Art" Currently, the amount of waste paper used as a raw material for paper manufacturing in Japan accounts for nearly 50% of the raw material for paper and paperboard production. However, from the standpoint of effective resource utilization, there is an increasing demand for recycling even more waste paper.

Examples of waste paper that can be made into recycled pulp include newspapers, cardboard, magazines, imitations, colored clay (including art paper), white paper, cards, special white, medium white, white manila, tickets, old recycled paper, and brown imitations. There are paper (including floating paper), mounts, ground certificates, balls, thermal paper, pressure-sensitive copying paper, CPO, etc., and these waste papers are generally processed through the disintegration process of disintegrating waste paper to create a pulp suspension, and the pulp suspension process. Recycled pulp is made into recycled pulp after undergoing a rough selection/selection process to separate foreign matter from the turbid liquid, a deinking process to separate printing ink, etc., and a bleaching process to whiten the color.

However, pressure-sensitive adhesive paper, which is processed into labels, sheets, patches, etc. and used widely for commercial, office, and household purposes, generally has a surface base material with adhesive applied to the back side of the paper base material, and a paper base material with an adhesive applied to the back side. It is composed of a release base material whose surface is coated with a release agent such as a silicon compound or a fluorine compound. The bond between the agent and the paper base material is strong, and with release paper in which a release layer is provided after laminating a plastic film to the paper base material, pulp disintegration is insufficient due to the influence of the plastic film. Therefore, currently it is disposed of as waste paper that cannot be recycled.

``Problems to be Solved by the Invention'' Therefore, the present invention provides a method for efficiently obtaining recycled pulp from used release paper, and in particular, uses a pigment coating layer as a base material for forming a release agent layer. To provide a method for efficiently separating and removing coating layers and release agent layers such as silicone from waste paper using a paper base material having release paper, and obtaining high-quality recycled pulp that does not cause trouble in the papermaking process. It is something.

"Means for Solving the Problems" The present invention provides a paper base material with a coating layer mainly composed of a pigment and an adhesive on at least one side, and a release agent layer on at least one side of the coating layer. Used release paper is subjected to mechanical agitation treatment under conditions of (a) pulp concentration of 15% or more and (b) temperature of 30°C or more, followed by flotation treatment and/or
Alternatively, it is a method for pulping waste paper from release paper, which is characterized by subjecting it to a cleaner treatment.

"Function" The paper base material of the release paper waste paper used in the present invention has pigments such as kaolin, calcium carbonate, aluminum hydroxide, and titanium oxide, and various copolymer latexes, starches, and casein on at least one side thereof. For example, coated paper such as coated paper, art paper, cast coated paper, medium coated paper, lightly coated paper, etc. is used. The method of the present invention is applied to used release paper in which at least one side of the paper base coating layer is coated with a release agent such as a silicon compound or a fluorine compound.

This release paper waste paper can be pulped to a certain extent by the presence of the coating layer, but even if it is simply mechanically stirred in an aqueous medium at a low pulp concentration (for example, 5% by weight), When the coated layer cannot be completely separated and removed, and the resulting recycled pulp is used, the release agent remaining on the coated layer has an adverse effect, contaminating the papermaking tools during the papermaking process, and causing contaminants in the product. They get in there and reduce the value of the product.

Therefore, as a result of intensive research into the separation and removal of the coating layer of waste release paper, the present inventors found that in order to sufficiently separate and disintegrate the coating layer, the pulp of waste release paper should be We found that concentration and temperature conditions are extremely important. As a result of further investigation, we found that the above-mentioned release paper waste paper has the following properties: (a) pulp concentration of 15% or more, Φ) temperature of 30°C.
It has been found that when the mechanical stirring treatment is performed under the above conditions, the coated layer is sufficiently destroyed and the pigment and mold release agent such as silicone are finely dispersed in the water.

Incidentally, if the pulp concentration is less than 15%, even if mechanical treatment is performed at a temperature of 30°C or higher, the coating layer will not be sufficiently destroyed. Therefore, a pulp concentration of 15% or more is required, but under high pulp concentration conditions exceeding 40%, mechanical stirring and mixing becomes difficult.
Most preferably, the bulb concentration is adjusted to about 0 to 35%. In addition, even if treated with a bulb concentration of 15% or more, 30%
Under temperature conditions below .degree. C., the coating layer is still insufficiently destroyed. Therefore, the temperature should be 30°C or higher, preferably 5°C.
It is desirable to adjust the temperature to a range of about 0 to 90°C.

In the method of the present invention, examples of devices for mechanically agitating waste release paper under such conditions include a high-density pulper having a helical rotor, a kneader, a disperser, a refiner, and the like. In addition, the kneader
When using a disperser, refiner, etc., the waste release paper may be cut into small pieces and disintegrated with water. It is efficient to perform the disintegration treatment by setting the pulp concentration and temperature conditions as described above. Furthermore, in order to promote disintegration during mechanical stirring treatment, alkaline chemicals, acidic chemicals, penetrants, surfactants, bleaching chemicals, etc. may be added.

In the method of the present invention, after subjecting release paper waste paper to a mechanical agitation treatment under specific conditions as described above, the obtained pulp suspension is subjected to a flotation treatment and/or a cleaner treatment, and the pulp suspension is The pigment and release agent dispersed therein are efficiently separated and removed.

Note that the used release paper used in the method of the present invention has an excellent printing effect because it has a pigment coating layer. Therefore, the printed paper is often treated as waste paper. In the case of such waste paper, it is preferable to add a deinking agent and perform flotation treatment to remove printing ink, or to combine flotation treatment and cleaner treatment to enhance the deinking effect. Furthermore, if foreign substances such as plastics or adhesives are mixed in, these foreign substances may be removed by using a screen treatment or a lightweight foreign substance removal cleaner.

Thus, in the recycled pulp obtained by the method of the present invention, not only pigments and adhesives in the coating layer but also release agents such as silicon compounds and fufu compounds are separated and removed very efficiently, so that they can be easily removed during the paper making process. Because it does not cause problems with paper-making equipment getting dirty and has no foreign substances, it can be reused as a high-quality paper raw material.

"Examples" The present invention will be described in more detail with reference to Examples below, but the present invention is of course not limited to these. In addition, % in the examples indicates weight % unless otherwise specified.

Example 1 A release paper coated with a silicon compound coated as a release agent on one side was used as release paper waste paper, and a pulp density of 15% was applied to a high-concentration pulper (manufactured by Kumagai Riki Kogyo ■, high-concentration pulp disintegrator). It was added together with 30°C hot water and subjected to 609i dissociation treatment.

The obtained pulp suspension was diluted to a pulp concentration of 0.8%, and a surfactant (manufactured by Kao ■) consisting of an ethylene oxide/propylene oxide adduct of fatty acids was used.

DI610) was added at 0.3% to the pulp, and the pulp was treated for 15 minutes with a floatator (manufactured by Kyoshin Sangyo, Fahrenwoald type flotation tester).

Next, this pulp was washed with water to obtain a white recycled pulp with a Hunter whiteness of 82%. Paper made using this recycled pulp has no impurities in the coating layer or release agent layer.
No stains on paper machine tools were observed.

Example 2 A release paper made of art paper coated with a silicon compound as a release agent was used as release paper waste paper.
Add it together with 50℃ hot water to make it 0%.
A disintegration treatment was performed for a minute.

The resulting pulp suspension was diluted to a pulp concentration of 0.5% and treated with a Hough Cleaner 600 model.

Next, this pulp was washed with water to obtain white recycled pulp with a Hunter whiteness of 83%. Paper made using this recycled pulp has no impurities in the coating layer or release agent layer.
No stains on paper machine tools were observed.

Example 3 A release paper made of printed coated paper coated with a silicon compound as a release agent was used as release paper waste paper, and a pulp density of 20% was applied to a high-density pulper [manufactured by Kumagai Riki Kogyo ■, high-density pulp disintegrator]. A surfactant consisting of an ethylene oxide/propylene oxide adduct of fatty acids (manufactured by Kao Corporation, DI610) was added together with 60°C warm water so that
was added at 0.3% to the pulp and subjected to disintegration treatment for 30 minutes.

The obtained valve suspension was diluted to a pulp concentration of 0.8%, treated with a floatator (Fahrenwald flotation tester manufactured by Kyoshin Sangyo) for 15 minutes, and further treated with a Huff Cleaner 600 model. .

Next, this pulp was washed with water to obtain a white recycled pulp with a Hunter whiteness of 81%. Paper made using this recycled pulp has no impurities in the coating layer or release agent layer.
Almost no printing ink was observed, and there was no staining of paper machine tools.

Example 4 Release paper A release paper prepared by applying a silicon compound as a release agent to a printed coated paper was used as waste paper, and first, a low-density pulper 1 manufactured by Kumagai Riki Kogyo ■, a low-density pulp disintegrator]
The mixture was added together with 60°C hot water so that the pulp concentration was 2%, and disintegrated for 20 minutes. Next, this pulp suspension was dehydrated to give a pulp concentration of 30%, and treated with a kneader (manufactured by Yamamoto Hyakuma Seisakusho) at 60'C.

The obtained pulp suspension was diluted to a pulp concentration of 2.0% and disintegrated in a disintegrator, further diluted to a pulp concentration of 0.8%, and treated with a surfactant (ethylene oxide/propylene oxide adduct of fatty acids). DI610 (manufactured by Kao Corporation) was added at 0.3% to the pulp, and treated for 15 minutes with a floatator (manufactured by Kyoshin Sangyo, Fahrenwald type flotation tester). After further treatment with Power Cleaner Model 600, the pulp was washed with water to obtain a white recycled pulp with a Hunter whiteness of 83%. The paper made using this recycled pulp had no impurities in the coated layer or peeled layer, almost no printing ink was observed, and there was no stain on the paper machine tools.

Example 5 Release paper A release paper coated with a silicon compound as a release agent on printed coated paper was used as waste paper, and first, a low-density pulper [manufactured by Kumagai Riki Kogyo ■, low-density pulp disintegrator] was used.
The mixture was added with hot water at 60'C so that the pulp concentration was 2%, and disintegrated for 20 minutes. Next, this pulp suspension was dehydrated to give a pulp concentration of 30%, and subjected to a kneader treatment (manufactured by Yamarei Hyakuma Seisakusho) at 60°C.

The obtained pulp suspension was diluted to a pulp concentration of 2.0% and disintegrated in a disintegrator, further diluted to a pulp concentration of 0.5%, and treated with a Power Cleaner Model 600. and,
A surfactant consisting of an ethylene oxide/propylene oxide adduct of fatty acids [manufactured by Kao ■, DI
610) was added at 0.3% to the pulp, and a floatator [manufactured by Kyoshin Sangyo, Fahrenwald type flotation tester] was added.
After treatment for 15 minutes, the pulp was washed with water to obtain a white recycled pulp with a Hunter whiteness of 83%. Paper made using this recycled pulp had no impurities in the coating layer or release agent layer, almost no printing ink, and no stains on paper machine tools.

Comparative Example 1 Example 1 except that in Example 1, a low-density pulper was used in place of the high-density pulper 1) as a mechanical disintegration treatment device for waste release paper, and the pulp concentration was also 2.0%. Regenerated pulp was obtained in the same manner as above.

The obtained recycled pulp was white with a Hunter whiteness of 81%, but paper made using this recycled pulp contained many coating layer components and release agent layer components as impurities, and paper machine tools stains were also observed.

Comparative Example 2 Recycled pulp was obtained in the same manner as in Example 1, except that the temperature when treating the waste release paper with the high-density pulper was 20°C.

The obtained recycled pulp was white with a Hunter whiteness of 81%, but paper made using this recycled pulp contained many coating layer components and release agent layer components as impurities, and paper machine tools stains were also observed.

Comparative Example 3 Regenerated pulp was obtained in the same manner as in Example 4 except that the kneader treatment was not performed.

The obtained recycled pulp had a low Hunter whiteness of 68%, and the paper made using this recycled pulp contained many coating layer components and release agent layer components as impurities, and a large amount of printing ink was also observed. It was done. In addition, the paper machine tools were extremely dirty.

"Effects" According to the method of the present invention, the release agent layer such as silicone can be efficiently separated and removed from waste release paper, making it possible to reuse waste release paper, which was conventionally considered difficult to convert into recycled pulp. Ta. Moreover, since high-quality recycled pulp is obtained that does not cause trouble during the paper-making process, the paper prepared by blending it maintains high quality with no impurities in the coating layer or rind layer, and almost no residual ink. Was.

Patent applicant: Kanzaki Paper Co., Ltd.

Claims (2)

[Claims] (1) A used release paper having a coating layer mainly composed of a pigment and an adhesive on at least one side of the paper base material, and a release agent layer on at least one side of the coating layer, (a) pulp A method for pulping used release paper, which comprises performing a mechanical stirring treatment under conditions of a concentration of 15% or more and (b) a temperature of 30° C. or more, followed by a flotation treatment and/or a cleaner treatment. (2) (a) Pulp concentration 20-35%, (b) Temperature 50%
The pulping method according to claim 1, wherein the waste release paper is mechanically agitated at a temperature of 90°C to 90°C.