JP2010001408A - Printing ink removing agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing ink removing agent for removing a printing ink layer from a substrate having the printing ink layer containing a pigment on the surface. <P>SOLUTION: The printing ink removing agent is characterized by including polyvinyl alcohol, a modified polyvinyl alcohol, or a polymer blend of the polyvinyl alcohol or the modified polyvinyl alcohol with other polymers. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing ink removing agent, and more particularly to a printing ink removing agent for removing the printing ink layer from a substrate having a printing ink layer containing a pigment on the surface thereof.

Recycled paper has been used from the viewpoint of effective use of resources. Recycled paper is generally manufactured from deinked pulp from which used ink is removed from waste paper such as newspapers and magazines, and paper is made using this deinked pulp alone or a mixture of deinked pulp with other pulp. It is manufactured.
Patent Document 1 describes a deinking agent for producing deinked pulp having excellent ink removability, high whiteness, and a small number of residual inks.

On the other hand, Reference 2 describes a coated paper in which an undercoat layer containing a pigment and starch and polyvinyl alcohol as an adhesive is provided between the base paper and the coated layer. By adopting the above-described configuration, the amount of the coating liquid that is absorbed by the base paper and does not affect the printability is reduced, and the base paper surface is sufficiently covered, for offset printing, gravure printing, etc. It has excellent printability.
Thus, conventionally, polyvinyl alcohol is used as an adhesive, a fiber treatment agent or an emulsifier because of its properties.
Japanese Patent Laid-Open No. 2001-200484 JP 2008-81899 A

However, a deinking process is indispensable for the production of recycled paper, but its production cost is higher than that of paper made from virgin pulp alone. In addition, wood pulp newly produced from wood has the feature that it can reduce the consumption of fossil fuel because black liquor (vegetable waste liquid) generated in the manufacturing process can be used as biomass fuel, whereas waste paper is used. In the case of recycling, there is no by-product of black liquor, so fossil fuel must be used, and the consumption of fossil fuel is said to be higher than that of wood pulp. In addition, the waste liquid discharged in processing steps using various chemicals such as ink removal and bleaching has a considerable impact on the environment. In addition, until the recovered waste paper is recycled, it undergoes processes such as disaggregation, deinking, bleaching, heating, drying, etc. to loosen the paper into fibers, so that the fibers become finer and weaker when reused several times. Cannot play. That is, it is not possible to make all the paper to be supplied from recycled paper. Thus, there is a need for a better recycled paper manufacturing method for improving the manufacturing cost for manufacturing recycled paper, the environmental load and the strength in the manufacturing process.
Further, the conventional deinking technology as described above is a technology for recycling printed paper, that is, paper, and almost completely denatures and deteriorates the printing ink portion on the surface of the new printed product. It is not a technology that removes it more than that. For products that are printed on the surface of a sheet or film of synthetic resin or the like, the technology for removing the printing ink is still not well established.

Therefore, the present invention can remove the printing ink on the surface of the printed paper product without substantially degrading or degrading the fiber of the paper substrate, such as damaging the fiber of the paper substrate. An object of the present invention is to provide a printing ink remover that facilitates the reproduction of a new paper base material for printing and that has a low environmental burden and impact. Another object of the present invention is to provide a printing ink remover that can be applied to sheets of synthetic resin other than paper, and products printed on the surface of a film substrate.

Therefore, as a result of intensive studies by the present inventor in order to solve the above-mentioned problems, a printing ink removing agent comprising polyvinyl alcohol, modified polyvinyl alcohol, or a polymer blend of polyvinyl alcohol or modified polyvinyl alcohol and another polymer. Is interposed between the surface of the base material and the pigment ink layer formed by printing on the base material, the printing ink layer can be easily removed from the base material having the printing ink layer containing the pigment on the surface. As a result, the present invention has been completed.
Therefore, the present invention relates to a printing ink remover described in the following (1) to (2).
(1) In a printing ink remover for removing a printing ink layer from a substrate having a printing ink layer containing a pigment on the surface, polyvinyl alcohol, modified polyvinyl alcohol, or polyvinyl alcohol or modified polyvinyl alcohol and other polymers And a polymer blend.
(2) The printing ink removing agent as described in (1) above, wherein the saponification degree of the polyvinyl alcohol is 98.0 to 99.5 mol%.

Polyvinyl alcohol, modified polyvinyl alcohol, or a polymer blend of polyvinyl alcohol or modified polyvinyl alcohol and other polymer used in the present invention has high solubility in warm water (water that is higher than normal temperature and lower than hot water). Have
Therefore, according to the present invention, the printing ink remover of the present invention having such a high hot water solubility is interposed between the printing ink layer and the substrate during printing, and is brought into contact with the warm water during recycling (regeneration). Thus, the printing ink layer can be easily removed from the substrate by dissolving the printing ink remover in warm water.
By using the printing ink remover of the present invention, when a product having a printing ink layer on the surface is recycled (recycled), it does not require many steps as in the prior art and is used in those steps. Since no chemicals are required, the manufacturing cost and the environmental load in the manufacturing process can be reduced.
In particular, for example, when the base material is paper, recycled paper can be produced by simply removing the printing ink layer on the paper surface without unraveling the paper into a fibrous form. Therefore, the printing ink removing agent of the present invention is used. As a result, the recycled paper produced has a high practical value with almost no deterioration in quality and strength.

The printing ink removing agent of the present invention includes polyvinyl alcohol having high hot water solubility, modified polyvinyl alcohol, or a polymer blend of polyvinyl alcohol or modified polyvinyl alcohol and another polymer.
The polyvinyl alcohol (hereinafter abbreviated as PVA) used for the printing ink remover may be either PVA or modified PVA. PVA is obtained by saponifying a polyvinyl acetate resin by a conventional method. Any one is acceptable. Examples of the modified PVA include a copolymer obtained by copolymerizing an ethylenically unsaturated monomer copolymerizable with vinyl acetate, and a saponified PVA.

Examples of the ethylenically unsaturated monomer copolymerizable with vinyl acetate include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, α-octadecene, acrylic acid, methacrylic acid, crotonic acid, malein Carboxylic acids such as acid, maleic anhydride, itaconic acid or salts thereof, mono- or dialkyl esters, nitriles such as acrylonitrile and methacrylonitrile, amides such as acrylamide and methacrylamide, ethylene sulfonic acid, allyl sulfonic acid, meta Olefin sulfonic acid such as allyl sulfonic acid or its salt, 2-acrylamido-2-methylpropane sulfonic acid or its salt, alkyl vinyl ethers, N-acrylamidomethyl trimethyl ammonium chloride, allyl trimethyl ammonium Polyoxyalkylene (meth) allyl ethers such as um chloride, dimethyldiallyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride, polyoxyethylene (meth) allyl ether, polyoxypropylene (meth) allyl ether, polyoxyethylene Polyoxyalkylene (meth) acrylates such as (meth) acrylate and polyoxypropylene (meth) acrylate, polyoxyalkylene (meth) acrylamides such as polyoxyethylene (meth) acrylamide and polyoxypropylene (meth) acrylamide, polyoxyethylene (1- (meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene vinyl ether, polyoxyethylene ali Amine, polyoxypropylene allylamine, polyoxyethylene vinylamine, polyoxypropylene vinyl amine.

  Examples of the modification method include acetoacetate esterification, acetalization, urethanization, etherification, grafting, phosphate esterification, and oxyalkyleneation of polyvinyl alcohol, preferably oxyalkyleneation.

  Examples of the polyvinyl alcohol include Gohsenol (registered trademark) manufactured by Nippon Synthetic Chemical Co., Ltd., Poval (registered trademark) manufactured by Kuraray Co., Ltd., Denkapoval (registered trademark) manufactured by Denki Kagaku Kogyo Co., Ltd., and the like.

  In addition, examples of other polymers mixed with polyvinyl alcohol or modified polyvinyl alcohol in the polymer blend include polyvinyl acetal, cellulose polymers [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose ( CMC) etc.], chitins, chitosans, starch; polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyvinyl ether (PVE) which are polymers having an ether bond; amide group or amide bond Polyacrylamide (PAAM), polyvinylpyrrolidone (PVP), which are polymers having a polyacrylic acid salt having a carboxyl group as a dissociative group, Ynoic acid resins, alginic acid salts, water-soluble polymers such as gelatins. When polyvinyl alcohol or modified polyvinyl alcohol is used as the polymer blend, the amount of polyvinyl alcohol or modified polyvinyl alcohol in the total mass of the polymer blend is preferably 90% by mass or more, and more preferably 95% by mass or more.

The printing ink remover of the present invention does not dissolve in low-temperature water, but when the printed substrate comes into contact (immersed) with warm water of 60 ° C. or higher in order to be easily separated from the substrate, It is required to have a property of easily dissolving. Here, as a reason why the printing ink removing agent of the present invention needs to exhibit solubility in warm water having a certain temperature or more, for example, when the printing ink removing agent dissolves in low temperature water, It cannot withstand use in daily life and cannot be used in products that are used in daily life. However, when immersed in high-temperature hot water to remove the printing ink layer, the strength of the substrate may be reduced, such as deterioration or damage depending on the substrate to which the printing ink remover is applied. For example, when removing the printing ink layer from a substrate containing synthetic fibers such as acrylic, polyurethane and polypropylene, it is preferable to employ warm water lower than 80 ° C. in order to prevent the strength of these fibers from decreasing.
Accordingly, polyvinyl alcohol or the like that satisfies these requirements preferably has a saponification degree of 95.0 mol% or more, and more preferably has a saponification degree of 98.0 mol% or more. The solubility of polyvinyl alcohol or the like is preferably less than 10 g with respect to 100 g of water at 20 ° C. and 60 g or more with respect to 100 g of water at 60 ° C.

  Examples of the substrate to which the printing ink removing agent of the present invention is applied include fine paper, medium paper, art paper, coated paper, synthetic paper, synthetic resin film and sheet, woven fabric and non-woven fabric. There is no particular limitation as long as it is a substrate on which pigment printing is performed. The woven fabric may be a woven fabric made of natural materials such as cotton, silk, hemp, etc., and the non-woven fabric may be a polypropylene non-woven fabric, polyester non-woven fabric or acrylic as a material in terms of ease of recycling, strength, moldability, etc. A resin nonwoven fabric is preferable, and a polypropylene nonwoven fabric that can be easily recycled is particularly preferable.

  Further, the printing ink remover of the present invention is applied on the surface of the substrate by, for example, processing the printing ink remover into a film form and laminating the surface of the substrate by heat fusion, A printing ink layer made of the printing ink remover is formed. Alternatively, the printing ink removing agent is applied, for example, by applying or spraying a printing ink removing agent on the surface of the substrate and impregnating the substrate. When a printing ink remover is laminated on the surface of a substrate such as paper or nonwoven fabric, a printing ink layer having a sufficient thickness is formed between the substrate and the printing ink layer. It can be easily separated when separating the layers. On the other hand, when the substrate is impregnated with a printing ink remover, the adhesion of the printing ink remover to the substrate is increased, so that the appearance is also beautiful.

  In the present invention, the printing method on the substrate to which the printing ink removing agent is applied is not particularly limited as long as it is a method conventionally used for printing the substrate, and includes relief printing, gravure printing, offset printing, silk Both screen printing and transfer printing can be employed. Of these, silk screen printing is preferred because printing is possible regardless of thickness, size, plane, and curved surface.

  Since the printing ink removing agent of the present invention has high hot water solubility, the substrate having the printing ink removing agent is kept at a constant temperature by interposing the printing ink removing agent between the substrate and the printing ink layer. By immersing in the above warm water, the printing ink remover dissolves in the warm water, and the printing ink layer can be easily separated from the surface of the substrate. At this time, by applying vibration, particularly ultrasonic vibration, to the substrate having the printing ink layer and the printing ink removing agent soaked in warm water, the printing ink layer is further easily separated from the substrate. Further, the printing ink constituting the separated printing ink layer is generally insoluble in water and does not dissolve even in warm water, so that only the printing ink layer can be easily removed from the warm water. In addition, when separating the printing ink layer from the non-woven fabric product of the present invention, only water is used without using an organic solvent, etc., which has an impact on the health of workers and also on the environment such as soil contamination. Absent.

Hereinafter, although an example is given and the present invention is explained in full detail, the present invention is not limited to these examples at all.
In this example, the following samples were used.
sample:
A.
Gohsenol N-300 (manufactured by Nippon Synthetic Chemical Co., Ltd.) Degree of saponification 98.5 mol%
B.
Gohsenol NL-05 (manufactured by Nippon Synthetic Chemical Co., Ltd.) Degree of saponification 98.5 mol%
C.
Hi-Selon H (made by Nippon Synthetic Chemical Co., Ltd.)
D.
Gohsenol GH-23 (manufactured by Nippon Synthetic Chemical Co., Ltd.) Degree of saponification 87.0 mol%

[Examples 1 and 2]
The printing ink remover consisting of the samples A and B was prepared in a film form. Each of these films was superimposed on the surface of the polypropylene nonwoven fabric, and the nonwoven fabric and the film were bonded together by heat welding. Furthermore, the printing ink layer was formed by carrying out silk screen printing from it, and the nonwoven fabric which has a printing ink layer was created.
Moreover, when the nonwoven fabric prepared as described above was placed in a hot water tank maintained at 65 ° C. and immersed for about 3 minutes while applying ultrasonic vibration, the printing ink layer could be separated from the surface of the nonwoven fabric sample. The nonwoven fabric sample from which the printing ink layer was separated was taken out from the hot water tank, and the separated printing ink was sinked to the bottom of the hot water tank because of its higher specific gravity than water. The sinking printing ink was removed from the hot water tank.
As described above, the non-woven fabric sample has a printing ink layer formed by interposing a printing ink remover having high hot water solubility between the polypropylene non-woven fabric and the printing ink layer even when printing is performed on the surface of the polypropylene non-woven fabric. It could be easily separated.

[Example 3]
Sample C in the form of a film was overlaid on the surface of the polypropylene nonwoven fabric in the same manner as in Examples 1 and 2, and the nonwoven fabric and the film were bonded together by heat welding. Subsequently, a printing ink layer is formed on the surface of the nonwoven fabric by the same procedure as in Examples 1 and 2, and the printing ink layer is obtained from the nonwoven fabric having the printing ink layer obtained by the same procedure as in Examples 1 and 2. Removed.
As a result, the nonwoven fabric and the printing ink layer on the surface thereof could be easily separated as in Examples 1 and 2.

[Comparative Example 1]
The test was performed in the same manner as in Example 1 except that Sample D was used. As a result, it was immersed in the hot water tank for the same time as in Example 1, but the printing ink was not separated from the substrate, and a part of the printing ink remained on the substrate surface.

  The printing ink removing agent of the present invention removes printing ink from a recyclable base material such as printed paper and non-woven fabric, regenerates the base material into a new base material, and reuses it to preserve the environment. -Very useful in terms of resource saving.

Claims (2)

In a printing ink removing agent for removing a printing ink layer from a substrate having a printing ink layer containing a pigment on the surface, polyvinyl alcohol, modified polyvinyl alcohol, or a polymer of polyvinyl alcohol or modified polyvinyl alcohol and another polymer A printing ink remover comprising a blend. The printing ink removing agent according to claim 1, wherein the saponification degree of the polyvinyl alcohol is 98.0 to 99.5 mol%.