JPH09165461A - Sheet for printing with water-base ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheet which is used for printing with a water-base ink and does not exhibit any change in physical properties, adhesiveness, and deliquescence even at high temp. and humidity by forming a water-base-ink absorption layer comprising a high-mol.-wt. polydioxolane on the surface of a thermoplastic resin substrate. SOLUTION: This sheet is obtd. by forming a water-base-ink absorption layer comprising a high-mol.-wt. polydioxolane represented by formula II and obtd. by polymerizing a 1,3-dioxolane monomer represented by formula I on at least one side of a substrate comprising a thermoplastic resin. The obtd. sheet is excellent in stability and resistances to humidity and water at high temp. and humidity, though having a high hydrophilicity, esp. a high solubility in warm water. Even when the sheet has absorbed moisture, it does not exhibit any change in physical properties (e.g. clarity of gloss), adhesiveness (e.g. stickiness or blocking), deliquescence, and blur of a printed water-base ink, thus exhibiting an excellent storage stability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for printing an aqueous ink using an ink jet printer or the like.
The present invention relates to a water-based ink printing sheet that can be used as a printing substrate. More specifically, a water-based ink water-absorbent ink containing a high molecular weight polydioxolane suitable for printing a water-based ink on at least one surface of a base material layer (A) made of a thermoplastic resin by using a gravure printing machine, an inkjet printer, or the like. The present invention relates to a water-based ink printing sheet provided with a hydrophilic layer (B).

[0002]

2. Description of the Related Art In recent years, in the printing industry, from the viewpoint of environmental pollution, hygiene, etc., for example, after performing gravure printing with a solvent-based ink on the front surface and / or the back surface of a plastic film or the like, the printed surface is printed. In the field of print-laminate printing, which coats a transparent film with excellent glossiness, or in the field of printing on a sheet for overhead projector (OHP) with a solvent-based ink using an inkjet printer, etc. There is a tendency to use water-based inks instead of system inks.

Conventionally, as a printing sheet or the like used for printing an aqueous ink, for example, a hydrophilic resin having a water-based ink absorbing property on the front surface and / or the back surface of a sheet made of a transparent plastic or the like. For example, a water-based ink printing sheet coated with polyethylene oxide (PEO), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), carboxymethyl cellulose (CMC), or the like is used.

However, a water-based ink printing sheet or the like obtained by laminating or coating such a hydrophilic resin on the surface of a sheet made of a thermoplastic resin causes tackiness (stickiness, etc.) under high temperature and high humidity and causes blocking. It tends to occur and the storage stability tends to decrease, and the physical properties and the like tend to change due to moisture absorption. Furthermore, the water-based ink water-absorbing layer made of the above-mentioned hydrophilic resin tends to be inferior in water resistance when water or the like is attached to the surface thereof, so that it easily dissolves. For example, an ink jet printer using the water-based ink as an OHP sheet. For example, prints, images, and the like that are printed by such as are easily melted and tend to bleed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation. An object of the present invention is to provide a water-based ink printing sheet which is excellent in stability under high temperature and high humidity, high moisture resistance, and water resistance even though it has high hydrophilicity, particularly solubility in hot water. Especially. Further, even when it absorbs moisture, it has excellent storage stability without change in physical properties (eg transparency, glossiness), development of tackiness (stickiness, blocking, etc.) and deliquescent phenomenon, and bleeding of printed aqueous ink. Another object is to provide a sheet for printing a water-based ink.

[0006]

Means for Solving the Problems That is, a feature of the present invention is that a high molecular weight obtained by polymerizing 1.3-dioxolane on at least one surface of a base material layer (A) made of a thermoplastic resin. It is intended to provide a sheet for printing an aqueous ink, which is formed by laminating or coating an aqueous ink absorbing layer (B) made of polydioxolane.

The water-based ink printing sheet according to the present invention is characterized by using polydioxolane having a number average molecular weight of 1,000 to 250,000, and the polyester resin is used as the thermoplastic resin forming the base material layer. At least one selected from the group consisting of resin, polycarbonate resin and cyclic polyolefin resin is used, and the thickness of the base material layer made of thermoplastic resin is 5 to 300 μm.
m, and the thickness of the water-based ink absorbing layer made of high molecular weight polydioxolane is 1.0 to 50 μm.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As the polyester resin used as the thermoplastic resin forming the base material layer (A) according to the present invention, a polyester resin containing a dicarboxylic acid component and a diol component can be exemplified. Examples of the dicarboxylic acid component include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, alicyclic dicarboxylic acids and the like, and derivatives and mixtures of these dicarboxylic acids. Specifically, for example, aliphatic dicarboxylic acids include adipic acid having 2 to 20 carbon atoms, sebacic acid, dodecanecarboxylic acid, and the like, and aromatic dicarboxylic acids include terephthalic acid, isophthalic acid,
Examples of naphthalene dicarboxylic acid and the like and examples of the alicyclic dicarboxylic acid include cyclohexanedicarboxylic acid and the like, and there is no particular limitation.

Examples of the diol component include aliphatic glycols, alicyclic glycols and the like, and derivatives and mixtures of these glycols. Specifically, the aliphatic glycols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,10-decanediol and the like can be exemplified, and the alicyclic glycol can be 1,4-cyclohexanediol and the like, respectively, and there is no particular limitation.

Further, as the polycarbonate resin,
For example, those produced from bisphenol A (4,4-dihydroxydiphenol-2,2-propane) by the phosgene method and the transesterification method can be exemplified.

Specifically, in the phosgene method, bisphenol A is produced by reacting bisphenol A with phosgene in the presence of an acid binder such as pyridine or caustic and a solvent (eg, methylene chloride, chlorobenzene, xylene). The polycarbonate to be used can be exemplified by a polycarbonate produced by separating phenol by a reaction between bisphenol A and diphenyl carbonate in the transesterification method, and there is no particular limitation.

As the cyclic polyolefin resin, at least one kind of α-olefin such as ethylene, propylene, butene, and 1,4-methylpentene-1, bicyclo [2.2.1] heptodiene derivative, tetracyclo- 3-dodecene derivative, hexacyclo-4-heptadecene derivative, octacyclo-5-dococene derivative, pentacyclo-4-hexadecene derivative, pentacyclo-3
A copolymer with at least one cyclic olefin selected from a pentadecene derivative, a heptacyclo-4-ecoisene derivative, a nonacyclo-5-pentacocene derivative, and the like can be given.

The base material layer made of the above polyester resin, polycarbonate resin and cyclic polyolefin resin preferably has a transparency of 10% or less in terms of haze. When it exceeds 10%, for example, when it is used as an OHP printing sheet or a print laminating sheet, it tends to be difficult to obtain images and prints having excellent gloss, transparency and sharpness.

The high molecular weight polydioxolane according to the present invention is a hot water-soluble resin represented by the chemical formula 1. Such a high molecular weight polydioxolane is produced by polymerizing the 1.3-dioxolane monomer represented by the chemical formula 2 by using an appropriate catalyst such as a composite polymerization catalyst composed of a heteropolyacid and a carbonyl compound. Is.

[0015]

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[0016]

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The high molecular weight polydioxolane is generally a hydrophilic resin which is soluble in hot water and disintegrates in cold water, and the resin is excellent in stability even under high temperature and high humidity. Therefore, a sheet or the like in which the resin is laminated or coated does not have a change in the physical properties of the surface, the development of tackiness (stickiness, blocking, etc.), the occurrence of deliquescent phenomenon, etc. even when moisture is absorbed, and the storage stability is improved. There is a tendency to do it.

Further, since the resin is thermoplastic, it can be melt-extruded by an extruder or the like and formed into a film or the like. Therefore, the monolayer film and the base material layer (A) made of a thermoplastic resin
A composite film such as an extruded laminated film formed by extruding on the surface of, or a dry laminated film formed by dry laminating a single layer film made of high molecular weight polydioxolane and a base material layer made of a thermoplastic resin via an adhesive, A high molecular weight polydioxolane and a thermoplastic resin other than this can be co-extruded to form a laminated film or the like, and the high molecular weight polydioxolane can be used as a base material for printing an aqueous ink by having at least one surface thereof. .

Also, hot water, an organic solvent such as toluene,
Using the solubility in chloroform etc., make a solution,
For example, it may be used as a film for printing an aqueous ink by coating at least one surface of a substrate layer made of the above-mentioned thermoplastic film or the like. At this time, the coating solution is not particularly limited, but may be 40
An example is a solution of 2 to 5% by weight in warm water at 0 ° C, and a solution of 5 to 10% by weight dissolved in an organic solvent such as chloroform.

As the high molecular weight polydioxolane according to the present invention, polydioxolane having a number average molecular weight of about 250,000 to 1,000 can be used when measured by gel permeation chromatography using polystyrene as a standard substance. Such polydioxolane can be suitably used as the water-based ink water-absorbing layer.

When the number average molecular weight is less than 1,000,
Polydioxolane has the property of becoming waxy easily,
There is a tendency that a tough film or the like cannot be formed even if a film is formed by a melt molding process or the like. Further, the polydioxolane is an organic solvent, for example, an organic solvent such as toluene or chloroform,
A coating film such as a coating sheet formed by coating a solution dissolved in warm water or the like on the surface of the above-mentioned transparent thermoplastic film has a tendency to develop tackiness or a deliquescent phenomenon. . Further, when an aqueous printer is used to print an aqueous ink on the coating sheet, there is a tendency that the fixability of the ink is poor and the printability is deteriorated, and that the bleeding of the aqueous ink occurs.

On the other hand, when the number average molecular weight exceeds 250,000, the melt viscosity of the polydioxolane is high and it becomes difficult to carry out melt molding. For example, it tends to be difficult to form a film, sheet or the like by a melt extrusion method or the like. Further, the solubility in an organic solvent (toluene, chloroform, etc.), hot water, etc. decreases, and it tends to be difficult to coat the base material layer made of the thermoplastic resin, for example.

Further, the high molecular weight polydioxolane according to the present invention may be blended with other hydrophilic hydrophilic thermoplastic resin or the like, if necessary, within a range that does not impair the characteristics thereof. The hydrophilic resin is not particularly limited, polyvinyl alcohol homopolymer, copolymer,
Examples thereof include cationized polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid and its metal salt, polyethylene glycol, polypropylene glycol, cellulose derivatives and alkylene oxide homopolymers or at least two or more alkylene oxide copolymers. Above all, alkylene oxide homopolymers and copolymers, which tend to improve the film-forming property and coating property of dioxolane, are preferable.

The alkylene oxide homopolymer or at least two or more kinds of alkylene oxide copolymers include, specifically, alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide and epichlorohydrin. Homopolymers or copolymers composed of at least two kinds selected from the group of the above alkylene oxides can be mentioned, but there is no particular limitation.

At this time, the compounding amount of the alkylene oxide homopolymer or copolymer can be exemplified as 49% by weight or less. When it exceeds 49% by weight, the moisture resistance of the water-based ink absorbing layer,
Water resistance tends to decrease, tackiness and the like tend to occur, and transparency also tends to decrease.

Further, the high molecular weight polydioxolane according to the present invention contains various additives and fillers as desired, such as heat stabilizers, antioxidants, antistatic agents, surfactants, lubricants, nucleating agents, antibacterial agents. Agents, flame retardants, pigments, or calcium carbonate, calcium sulfate, barium sulfate, magnesium hydroxide, silica, mica, talc, organic fillers and the like can be added, but there is no particular limitation and it is not necessary to add them.

At this time, as the antistatic agent among the above additives, cationic quaternary ammonium salts such as trimethylammonium chloride and 2- (meth) acryloyloxyethyltrimethylammonium chloride can be exemplified. Such additives improve the fixability of water-based ink,
It tends to prevent bleeding of printed water-based inks.

The method for producing a sheet for printing an aqueous ink according to the present invention includes a method of laminating a high molecular weight polydioxolane and a thermoplastic resin by a coextrusion method, and a high molecular weight on at least one surface of a base material layer made of a thermoplastic resin. An extrusion lamination method in which polydioxolane is melt-laminated and a dry lamination method in which a film made of a high molecular weight polydioxolane and a film made of a thermoplastic resin are adhered via an adhesive or the like can be exemplified, but there is no particular limitation.

Alternatively, at least one surface of the base layer film made of a thermoplastic resin may be coated with a solution prepared by dissolving polydioxolane in an appropriate solvent. Examples of coating methods include gravure coating, reverse roll coating, dip coating.
Coating may be performed by an appropriate method such as coating, air knife coating, bar coating, etc., and there is no particular limitation.

As the coating solution, an aqueous solution,
A solution of 0.5 to 15% by weight in 40 ° C. hot water and a solution of 5 to 30% by weight in an organic solvent such as toluene and chloroform can be exemplified. In the case of an aqueous solution, if it is less than 0.5% by weight, the desired film thickness tends not to be obtained, for example, at the time of coating, and if it exceeds 15% by weight, the viscosity tends to increase and a good coating film can be obtained. It tends not to be obtained.
If the amount of the organic solvent solution is less than 5% by weight, the desired film thickness tends to be unobtainable, and if it exceeds 30% by weight, the viscosity tends to be high and a good coating film may not be obtained.

The aqueous ink printing sheet according to the present invention comprises
Furthermore, if necessary, for example, in order to improve the adhesion between the high molecular weight polydioxolane and the base material layer made of a thermoplastic resin, the laminate film or coating film obtained above is stretched by a known appropriate method and conditions. However, there is no particular limitation. Further, if necessary, for example, in order to obtain dimensional stability or to prevent curling or the like, heat setting may be performed by a known method and condition without any particular limitation.

The thickness of the aqueous ink printing sheet according to the present invention may be 1.0 to 50 μm as the thickness of the aqueous ink water absorbing layer (B) made of high molecular weight polydioxolane. If it is less than 1.0 μm, the water absorption amount of the water-based ink tends to be small, and the printability of a printed image or the like tends to deteriorate.
If it exceeds 50 μm, the transparency tends to decrease.

The thickness of the base material layer (A) made of a thermoplastic resin may be such that it can support the water-based ink water absorbing layer (B), and it may be 6 to 300 μm. Therefore, the total thickness of the water-based ink printing sheet is 6 to 350 μm. If it exceeds 350 μm, clear printing of a printed image or the like tends to be impossible, and if it is less than 6 μm, printing of a printed image or the like tends to be difficult and workability tends to deteriorate.

The aqueous ink printing sheet according to the present invention comprises:
Although not particularly limited, surface treatment can be performed in order to improve printability, laminatability, adhesive coatability, and the like. The surface treatment method is not particularly limited, and examples thereof include corona discharge treatment, plasma treatment, flame treatment, and acid treatment. The corona discharge treatment is preferable because it can be easily carried out before the winding step in the process for producing a sheet for printing an aqueous ink and is simple, but there is no particular limitation, and surface treatment may be omitted.

The application of the water-based ink printing sheet according to the present invention includes a print laminate water-based ink printing sheet, an over head projector (OHP) printing sheet produced by printing with a water-based inkjet printer, and the like. Can be suitably used as. Further, it can be used for applications such as a packaging film, an agricultural sheet, etc., in addition to a print laminate printing sheet, an aqueous inkjet printer printing sheet, etc., and it can be used in various industrial fields.

[0036]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In the following examples of the present invention, measurement and evaluation of each inspection item were performed by the following methods.

[Number average molecular weight]: Measured by gel permeation chromatography using polystyrene as a standard substance. [Printability]: Printed with a commercially available inkjet printer [BJ600 manufactured by Canon Inc.] and visually evaluated. ◎… Excellent. Good ... Excellent. Δ: Use is not hindered. ×: Poor. [Water resistance]: The ink fixability at the time of wiping off water droplets and changes in the water absorbing layer were visually evaluated. A: There is no ink dropout. ○: Almost no ink is dropped. △: Part of the ink comes off, but printing and image identification are possible. ×: Ink dropped out and prints and images could not be identified. [Storage resistance]: The bleeding property of the ink was visually evaluated after the printing was performed at 40 ° C. and 90% RH for 5 days. ◎ ... There is no blur at all. O ... Almost no blur. B: Bleeding is easily recognized. ×: There are many bleeds. [Adhesion resistance]: The adhesion at 26 ° C. and 65% RH was evaluated. A: No tackiness was observed. ◯: Adhesiveness is hardly recognized. △: Adhesiveness is recognized but can be used. ×: Strong adhesion.

Example 1 As the base material layer (A), a polyethylene terephthalate sheet (wetting tension 54 dyne / cm) having a thickness of 100 μm and having one surface subjected to corona discharge treatment was used. As a coating solution,
Polydioxolane (number average molecular weight 20,000) 5 g dissolved in chloroform 45 g Polydioxolane concentration 1
Porous silica (particle diameter: 1.4 μm) was added to a 0% by weight polyoxolane solution in an amount of 1% by weight based on the polyoxolane to prepare a coating solution of polydioxolane. Then, the solution was coated on the surface of the polyethylene terephthalate sheet treated with corona discharge using a bar coat and dried at 100 ° C. for 3 minutes to obtain a sheet for printing an aqueous ink comprising a polyethylene terephthalate sheet and polydioxolane. It was The aqueous ink printing sheet had a base material layer of 100 μm and an aqueous ink water absorption layer of 10 μm.
m. An aqueous ink was printed on the polyoxolane layer surface of the aqueous ink printing sheet using an inkjet printer, and the printability, water resistance, storage resistance, and tack resistance were evaluated, and the results are shown in Table 1.

Example 2 A composition prepared by adding 5000 ppm of silica (particle size 5 μm) to a mixture of 95 parts by weight of polydioxolane (number average molecular weight 20,000) and 5 parts by weight of thermoplastic polyethylene oxide was added to a cylinder. It is supplied to a 40φT die set to a temperature of 120 ° C and a T-die temperature of 110 ° C, melt-kneaded, extruded on a chill roll set to 15 ° C, cooled, and then taken out. I got a film. Then, the film was thermocompression-bonded at 85 ° C. to a corona discharge treated surface of a 100 μm thick polyethylene terephthalate sheet (wetting tension 54 dyne / cm) which had been subjected to corona discharge treatment, to obtain a water-based ink printing sheet. The water-based ink was printed on the surface of the high molecular weight polydioxolane of the water-based ink printing sheet by using an inkjet printer, and the printability, water resistance, storage resistance, and tack resistance were evaluated, and the results are shown in Table 1.

Comparative Example 1 A coating solution was prepared by dissolving 5 g of polyethylene oxide in 95 g of toluene and adding polyethylene oxide solution having a polyethylene oxide concentration of 5% by weight to porous silica (particle size 1.4 μm) based on polyethylene oxide.
A water-based ink printing sheet was obtained in the same manner as in Example 1 except that a coating solution containing polyethylene oxide was added. A water-based ink was printed on the polyethylene oxide layer surface of the water-based ink printing sheet using an inkjet printer, and printability, water resistance, storage resistance, and tack resistance were evaluated, and the results are shown in Table 1.

Comparative Example 2 An aqueous ink printing sheet was obtained in the same manner as in Example 2 except that polydioxolane was changed to polyethylene oxide. A water-based ink was printed on the polyethylene oxide surface of the polyethylene oxide printing sheet using an inkjet printer, and the printability, water resistance, storage resistance, and tack resistance were evaluated, and the results are shown in Table 1.

As is clear from Table 1, the aqueous ink printing sheet comprising the high molecular weight polydioxolane according to the present invention has extremely excellent printability, water resistance, storage resistance, and tack resistance, and also has a tough coating. Can be formed.

[0043]

EFFECTS OF THE INVENTION Since the aqueous ink printing sheet according to the present invention has a film made of high molecular weight polydioxolane, changes in physical properties, development of tackiness (stickiness etc.) and deliquescent phenomenon even under high temperature and high humidity. And the like, and the preservability becomes excellent. Furthermore, when a water-based ink is printed on the water-based ink printing sheet according to the present invention by using, for example, an ink jet printer, a printed matter without ink bleeding can be obtained. Therefore, the water-based ink printing sheet can be suitably used as print printing or an overhead projector (OHP) sheet.

[Table 1]

Claims (4)

[Claims] 1. A water-based ink absorbing layer (B) made of a high molecular weight polydioxolane obtained by polymerizing 1.3-dioxolane is laminated or coated on at least one surface of a base material layer (A) made of a thermoplastic resin. A sheet for printing water-based ink. 2. A polydioxolane having a number average molecular weight of 1,
The water-based ink printing sheet according to claim 1, which is 000 to 250,000. 3. The water-based ink printing according to claim 1, wherein the thermoplastic resin forming the base material layer is at least one selected from the group consisting of polyester resins, polycarbonate resins and cyclic polyolefin resins. Sheet. 4. The base material layer (A) made of a thermoplastic resin has a thickness of 5 to 300 μm, and the water-based ink absorbing layer (B) made of high molecular weight polydioxolane has a thickness of 1.0 to 50 μm. 1. The sheet for printing an aqueous ink according to 1.