JP2001121812A - Recording sheet and recorded matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a recording sheet and a recorded matter having good ink absorbability and good dye fixability and no fading even for a long term preser vation after printing. SOLUTION: The recording sheet comprises a porous ink receiving layer containing a hindered amine compound and a salt of an acid on a base material. The recorded matter comprises an ink receiving layer containing a hindered amine compound and a salt of an acid on a base material in such a manner that a dye is carried to the layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet and a recorded matter, and more particularly, to a recording sheet and a recorded matter which do not fade even after long-term storage after printing and are particularly preferably used for ink jet recording.

[0002]

2. Description of the Related Art In recent years, it has been widely used to form images using various printers such as an ink jet system, an electrostatic transfer system, and a sublimation type thermal transfer system. When performing such image formation, particularly when performing image formation using a printer using an inkjet method, plain paper cannot provide sufficient ink absorbency and resolution, and a transparent image may be obtained. For example, Japanese Patent Laid-Open No. 2-2766
No. 70 and the like have proposed a recording sheet having an inorganic porous layer formed on a substrate.

[0003] As an ink used in such an ink jet recording system, a dye ink obtained by dissolving a dye in water is mainly used. The recording sheet having the inorganic porous layer described above has an advantage that the ink absorbability is good and the dye fixability is also good. However, when an image is formed on a recording sheet having the above-mentioned inorganic porous layer with an ink using a dye, an image obtained during long-term storage after image formation may be discolored.

Conventionally, as a measure for preventing such fading of an image, Japanese Patent Application Laid-Open No. 7-314882 discloses a method.
It is disclosed that a thiocyanate or a hindered amine compound is added to the ink receiving layer. However, since hindered amine compounds are hardly soluble in water, an organic solvent must be used for coating, and they cannot be added directly to an aqueous coating liquid. There are various inconveniences such as having to do so.

Further, when a hindered amine compound is used for addition to a resin or the like, it has been considered that the addition of an acid must be avoided because an acid has an inhibitory action on the hindered amine compound. It is considered that it is difficult to use these for preventing the fading of the recording sheet.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a recording sheet having good ink absorbency and good dye fixability, which does not fade even after long-term storage after printing. And to provide recorded materials.

[0007]

The above objects of the present invention can be attained by providing a recording sheet having a porous ink receiving layer containing a hindered amine compound and an onium salt of an acid on a substrate.

In the recording sheet of the present invention, it is preferable that the porous ink receiving layer is a layer composed of boehmite and a binder.

It is preferable that the recording sheet is a recording medium for an ink jet printer.

Further, the above object of the present invention is to provide a
This problem can be solved by providing a recorded matter having an ink receiving layer containing an onium salt of a hindered amine compound and an acid, and having a dye supported on the porous ink receiving layer.

In the recorded matter of the present invention, it is preferable that the porous ink receiving layer is a layer composed of boehmite and a binder.

It is preferable that the onium salt is contained in the porous ink receiving layer of the recording sheet and the recorded matter in an amount of 0.01 to 10% by weight.

[0013]

The present inventors have assiduously studied and, as a result, have found that an onium salt of a hindered amine compound and an acid has a very large effect on improving the light fastness of an ink jet recorded material, and have reached the present invention. . These hindered amine compounds function alone as a discoloration inhibitor,
Discoloration of the stored ink after printing can be prevented. It is considered that the function of the anti-fading agent is to prevent oxidation by singlet oxygen or oxidizing gas in the air. By using such a hindered amine compound as an onium salt with an acid as in the present invention, it is considered that the above-mentioned disadvantages of the conventional hindered amine compound can be improved and a more excellent discoloration preventing effect can be obtained. .

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The recording sheet of the present invention is particularly excellent in ink absorption and fixing properties, so that it can express clear colors and high color densities and can form sharp dots. It is particularly preferably used as a recording medium.

Examples of the hindered amine compound used in the present invention include 1,2,2,6,6-pentamethylpiperidine derivatives tinuvin 123, tinuvin 144, tinuvin 765, tinuvin 770, tinuvin 622, chimassorb 944, and chimassorb 119 (chibasorb 119).・ Speciality ・
ADK STAB LA-52, ADK STAB LA-57, ADK STAB LA-62, ADK STAB LA-67, ADK STAB LA-82, ADK STAP LA-87, ADK STAB LX-332 (Asahi Denka Co., trade name), etc. But are not limited to these.

Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and amidosulfuric acid, formic acid, acetic acid, propanoic acid, butyric acid, oxalic acid, and the like.
Any of organic acids such as lactic acid, tartaric acid and succinic acid can be used.

The above-mentioned salt of a hindered amine compound and an acid is formed by the coordination of a hydrogen ion supplied by an acid to an unpaired electron of the amine, and a 1.2% equivalent of a 10% aqueous solution of amidosulfuric acid is added to the hindered amine compound. Is added to obtain an aqueous solution of an amide sulfate of a hindered amine compound. The formation of the compound can be confirmed also from the IR spectrum of the solution after the aqueous solution becomes slightly acidic (pH 6) and the water is evaporated. Usually, the aqueous solution is used for the next process.

As a method for imparting a salt of a hindered amine compound and an acid to the porous ink receiving layer, the above-mentioned anti-fading agent,
That is, a method in which an onium salt of a hindered amine compound and an acid is applied by a dipping method or a spray method is preferably employed. Alternatively, a method in which the above-described fading inhibitor is mixed in advance with the raw material for forming the porous ink receiving layer can also be used.

The content of the anti-fading agent used in the present invention is set at 0.1 based on the weight of the porous ink receiving layer.
It is preferably from 0.01 to 10% by weight. When the content of the above-mentioned anti-fading agent is less than 0.01% by weight, the effect of the present invention is not sufficiently exhibited, and there is a possibility that the discoloration of the ink may occur. When the content of the above-mentioned anti-fading agent is 10
If the content is more than 10% by weight, the absorbability of the porous layer may be impaired. More preferably, the content of the above-mentioned anti-fading agent is 0.1 to 10% by weight.

The anti-fading agent used in the present invention comprises:
Although it is effective even when used alone, the effect can be further enhanced by using several kinds of hindered amine compounds in combination. At this time, the content of the above-mentioned anti-fading agent mixture is 0.01% based on the weight of the porous ink receiving layer.
It is preferably from 10 to 10% by weight. When the total content of the above-mentioned anti-fading agent mixture is less than 0.01% by weight, the effects of the present invention are not sufficiently exhibited, and the ink may be discolored, which is not preferable. If the total content of the above-mentioned anti-fading agent mixture exceeds 10% by weight, the absorbability of the porous layer may be impaired, which is not preferred. The total content of the above-mentioned anti-fading agent mixture is 0.1 to 10%.
It is more preferable to set the weight%.

In the present invention, the porous ink receiving layer comprises:
An inorganic porous layer capable of absorbing and fixing ink during recording. If the thickness of the porous ink receiving layer is too small, the dye cannot be sufficiently supported, and only a print having a low color density may be obtained. Conversely, if the thickness of the porous ink receiving layer is too large, the strength of the porous ink receiving layer may be reduced, or the transparency may be reduced, and the transparency or texture of the printed matter may be impaired. The preferred thickness of the porous ink receiving layer is 1 to 50 μm.

It is preferable that the porous ink receiving layer has a structure in which inorganic particles are bonded preferably by a binder.
The material of the inorganic particles is preferably silica or alumina or a hydrate thereof. Among these materials, boehmite is particularly preferred. This is because the porous layer made of boehmite has good absorbability and selectively adsorbs the dye well, so that a clear recorded matter having a high color density can be obtained using various ink jet recording methods. Here, boehmite is Al ₂ O ₃ .nH ₂ O
It is an alumina hydrate represented by the composition formula (n = 1 to 1.5), and the porous layer made of boehmite is an aggregate having a pore structure.

When the porous ink receiving layer is composed of boehmite and a binder, the total content of the above-mentioned anti-fading agent or the above-mentioned anti-fading and hindered amine compound is 0.05 to 50 mg / g of boehmite. Is preferred. A more preferred range is 0.1 to 20 m
g.

It is sufficient that the ink receiving layer has pores whose pore structure substantially has a radius of 1 to 20 nm and a pore volume of 0.3 to 1.0 cm ³ / g. It is preferable because it has excellent absorbability and transparency can be obtained. If an ink receiving layer having a pore structure in this range is used, a transparent recording sheet can be obtained when the substrate is transparent. When the substrate is opaque, it is possible to impart necessary physical properties such as ink absorbency to the recording sheet without impairing the texture of the substrate. More preferably, the average pore radius of the ink receiving layer is in the range of 3 to 10 nm. The pore size distribution is measured by a nitrogen adsorption / desorption method.

In order to produce the ink receiving layer having the above-mentioned pore structure, it is preferable to use, for example, a boehmite sol, apply it on a base material together with a binder, and dry it. As a coating method, a die coater, a roll coater, an air knife coater, a blade coater, a rod coater, a bar coater, or the like can be used.

Examples of the binder used in the porous ink receiving layer include starch and modified products thereof, polyvinyl alcohol and modified products thereof, SBR (butadiene styrene rubber) latex, NBR (butadiene acrylonitrile rubber) latex, hydroxycellulose, hydroxymethylcellulose, and the like. Water-soluble and alcohol-soluble polymers such as hydroxyethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyacrylic acid, and polyacrylamide can be used. If the amount of the binder used is too small, the strength of the porous ink receiving layer may be insufficient. On the other hand, if the amount is too large, the amount of the ink absorbed or the amount of the dye carried may be low. It is preferably about 50% by weight.

In the present invention, various substrates can be used. For example, substrates generally used in the coated paper field, such as acidic paper, neutral paper, synthetic paper, and film, can be used. In particular, as the film, a polyester resin such as polyethylene terephthalate, polybutylene naphthalate, and polyester diacetate, a polycarbonate resin film, and a plastic such as a fluororesin such as ETFE can be suitably used.
These substrates may be subjected to a corona discharge treatment, an undercoat or the like for the purpose of improving the adhesive strength of the porous ink receiving layer.

Further, in the recording sheet of the present invention, a layer can be further provided on the above-mentioned ink receiving layer for the purpose of modifying the surface characteristics. Examples of such a layer include those provided with a composition in which colloidal silica or colloidal alumina is dispersed in various polymers so that the layer thickness is 0.05 μm to 5 μm.

[0029]

EXAMPLES The present invention will be described below with reference to examples.
The invention is not limited to these examples.
Examples 1 to 9 are working examples, and examples 10 and 11 are comparative examples.

(Examples 1 to 9) In a glass reactor having a capacity of 2 liters, 540 g of water and 676 of isopropyl alcohol were added.
g, and the liquid temperature was heated to 75 ° C. by a mantle heater. While stirring, aluminum isopropoxide 3
06 g was added, and the solution temperature was maintained at 75 to 78 ° C. for 5 minutes.
Time hydrolysis was performed. Thereafter, the temperature was raised to 95 ° C., and acetic acid 9
g was added and peptized for 48 hours at 75-78 ° C. The solution was further concentrated to 900 g to obtain a white sol. The dried product of this sol was pseudo-boehmite.

1 part by weight of polyvinyl alcohol was added to 5 parts by weight of the alumina sol, and water was further added to prepare a slurry having a solid content of about 10%. This slurry is applied onto a substrate made of polyethylene terephthalate (thickness: 100 μm) subjected to corona discharge treatment using a bar coater so that the layer thickness when dried becomes 30 μm, and dried to give boehmite porous material. An ink receiving layer was formed.

The coated surface of the recording sheet obtained as described above was immersed in a 5% by weight aqueous solution of various treatment chemicals shown in Table 1, and the solution was uniformly applied. This was suspended vertically and air-dried, and then heated and baked at 140 ° C. for 4 minutes in a drum dryer to prepare recording sheets of Examples 1 to 9. In this example, an onium salt of hydrochloric acid, amidosulfuric acid and the following hindered amine compound was used as a treatment agent for preventing fading. The amount of the acid used was 1.2 times equivalent of the base amount of the hindered amine compound.

As the hindered amine compound, a compound selected from Tinuvin and Adecastab was used. Here, Tinuvin is a trade name of Ciba Specialty Chemicals, and is a registered trademark of Ciba Specialty Chemicals. Tinuvin 144 is 2-[(3,
5-bis-1,1-dimethylethyl) -4-hydroxyphenylmethyl] -2-butylmalonate
2,6,6-pentamethyl-4-piperidinyl) and tinuvin 123 are bis (1-octyloxy-sebacate)
2,2,6,6-tetramethyl-4-piperidyl) and tinuvin 622 are polycondensed dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine succinate The product, tinuvin 944, is poly [{6- (1,1,3,3-tetramethylbutyl) -amino-1,3,5-triazine-2,4-diyl}.
{2,2,6,6-tetramethyl-4-piperidyl) imino {hexamethylene} (2,2,6,6-tetramethyl-4-piperidyl) imino}, tinuvin 119,
N, N'-bis (3-aminopropyl) -ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,
6,6-pentamethyl-4-piperidyl) amino] -6
-Chloro-1,3,5-triazine condensate, tinuvin 7
65 is bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, and tinuvin 770 is bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate.

ADK STAB is a trade name of Asahi Denka Kogyo Co., Ltd. and is a registered trademark of the company. ADK STAB LA
-52 is tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, and LA-57 is tetrakis (2,
2,6,6-tetramethyl-4-piperidyl) -1,
2,3,4-butanetetracarboxylate, LA-6
2 is 1,2,2,6,6-pentamethyl-4-piperidinol and tridecyl alcohol and 1,2,3,4-
An ester with butanetetracarboxylic acid, LA-67,
It is an ester of 2,2,6,6-tetramethyl-4-piberidinol and tridecyl alcohol with 1,2,3,4-butanetetracarboxylic acid. ADK STAB LX-
332 is an emulsified compound of LA-62, a hindered amine compound.

The above-mentioned onium salt was produced as follows. To 50 g of LA52 (molecular weight: 847) were added 5.50 g of a 10% aqueous solution of amidosulfuric acid and 24.5 g of water to obtain a colorless and transparent aqueous solution having a solid content of 5.0%. This was used in the examples without purification. The formation of the amide sulfate of the hindered amine compound was confirmed by an infrared spectrum.

(Comparative Example) (Example 10) ADK STAB LX-332 (Asahi Denka Co., Ltd.) was used as an anti-fading agent in the ink receiving layer used in Examples 1 to 9.
Example 9 was a comparative example in which an ink-receiving layer was formed on a substrate in the same manner as in Examples 1 to 9 except that the same was applied. (Example 11) An ink receiving layer was formed on a substrate in the same manner as in Examples 1 to 9 except that the anti-fading agent was not applied to the ink receiving layer used in Examples 1 to 9 to obtain a comparative example. did.

(Evaluation Method) Content of anti-fading agent The content of the anti-fading agent was determined by cutting out a part of the recording sheet obtained as described above and adding 1 part to aqueous hydrochloric acid or toluene.
The extract after immersion for 2 hours was quantified by a spectroscopic analysis method using an ultraviolet / visible spectrum or ion chromatography to determine the amount (loading amount) of the anti-fading agent in the porous ink receiving layer of the recording sheet. At this time, the calibration curve was obtained by directly adding and mixing an aqueous solution of an amide sulfate of a hindered amine compound to alumina sol, and was prepared using a standard sample having a known loading amount. B. Inkjet Printing Characteristics Inkjet printing characteristics were evaluated by recording on the recording sheet of the present example, which had been subjected to the above-described chemical treatment, using an inkjet printer Seiko Epson PM750C, and visually observing the printability. C. Fading resistance The corrosion resistance was evaluated by applying a black ink containing Food Black 2 to a recording sheet and measuring 320 (w / m) with a Xenon weather meter (machine name: FAL-25AX) manufactured by Suga Test Instruments.
² ) A light fastness test for 20 hours was performed to examine the degree of black fading. For comparison, the fading condition was examined by the same method for the recording sheet of the comparative example without the chemical treatment.
The evaluation of the degree of fading was expressed in three stages: high degree of fading (x), medium degree of fading (△), and low degree of fading (○).

In Table 1, the unit of the concentration of the treatment chemical in the treatment liquid is a percentage by weight, and Tinuvin 144 / HCl = 5.
Indicates that the concentration of Tinuvin 144 was 5% by weight and used as a hydrochloride. The unit of the amount of the treatment agent carried on the recording sheet is pseudo boehmite (Al ₂ O ₃ .nH ₂ O) 1
It is the number of grams per 00 g. ASA is an amidosulfuric acid (Am
id sulfonic acid), indicating that it was used as an amide sulfate. The results obtained are shown in Table 1 together with the results of Comparative Examples.

According to Table 1, in the case of the present example in which the onium salt of a hindered amine compound and an acid was used as the treating agent, it was particularly excellent in the anti-fading property and no sheet coloring was observed.

When recording was performed on the recording sheet of this example using an ink jet printer, a good image excellent in ink absorbency and dye fixability was obtained.

[0041]

According to the present invention, the ink absorbability is good, the dye fixability is good, and no fading occurs even after long-term storage, and it is effective for various recording systems.
Particularly, it is possible to provide a recording sheet and a recorded matter suitable for a recording medium for an ink jet printer.

[Table 1]

Claims (6)

[Claims] 1. A recording sheet having, on a substrate, a porous ink receiving layer containing an onium salt of a hindered amine compound and an acid. 2. The recording sheet according to claim 1, wherein the porous ink receiving layer is a layer composed of boehmite and a binder. 3. The recording sheet according to claim 1, wherein the onium salt is contained in the porous ink receiving layer in an amount of 0.01 to 10% by weight. 4. A recorded matter having an ink receiving layer containing an onium salt of a hindered amine compound and an acid on a substrate, and a dye carried on the porous ink receiving layer. 5. The recorded matter according to claim 4, wherein the porous ink receiving layer is a layer composed of boehmite and a binder. 6. The recorded matter according to claim 3, wherein the onium salt is contained in the porous ink receiving layer in an amount of 0.01 to 10% by weight.