JPS63176173A - Sheet for ink jet recording - Google Patents

Abstract

PURPOSE:To provide an ink jet recording sheet having excellent ink absorbing performance and water-proof performance, by incorporating modified polyvinyl alcohol having acetoacetyl group and at least one kind of organic compound selected from aldehydes, amines, epoxies, etc., into basic supporting material. CONSTITUTION:Modified PVA having acetoacetyl group can be obtained by additionally reacting normal completely saponified or partially saponified PVA with diketene or by ester exchange reaction with acetoacetyl ester. Content of acetoacetyl group is selected from 0.1-20mol %, preferably from 0.5-10mol %. Mixing ratio between modified PVA and at least one kind of organic com pound selected from aldehydes, amines, epoxies, etc., is selected from 100/1-100/20, preferably from 100/2-100/10. Any transparent or opaque basic supporting material known in prior art can be employed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording sheet, and particularly to an inkjet recording sheet that has excellent ink absorbency and excellent water resistance.

B. Conventional technology The inkjet recording method is being applied to facsimiles, various printers, etc. because of its low noise, ease of colorization, and high-speed recording. Conventionally, ordinary paper has been used as a recording material for inkjet recording methods. However, as the performance of inkjet recording machines improves, such as higher recording speeds and multicolor recording, more advanced properties are being required for inkjet recording sheets. Firstly, the ink absorption speed is high; secondly, the diameter of the ink dots does not become larger than necessary; and thirdly, the inkjet recording sheet itself has high water resistance.

In order to meet these requirements, various studies have been made in the past, such as using paper or water-soluble resin as an absorbent material for water-bathable inkjet ink. The current situation is that it is far from meeting the requirements for practical use, such as increased size and significantly lower water resistance.

C1 Problems to be Solved by the Present Invention An object of the present invention is to provide an inkjet recording sheet that satisfies the above requirements and is particularly excellent in ink absorption and water resistance.

Yet another object of the present invention is to
To provide an inkjet recording sheet that has a high transparency that can be used for observation by projecting a recorded image onto a screen etc. using an optical device such as the above, or for observation of transmitted light such as a color display. be.

D1 Means for Solving the Problems of the Present Invention As a result of intensive studies to solve the above-mentioned problems and achieve the above-mentioned purpose, we found that modified polyvinyl alcohol (hereinafter referred to as polyvinyl alcohol) having an acetoacetyl group on the supporting substrate Inkjet recording sheets containing alcohol (abbreviated as PVA) and at least one organic compound selected from aldehydes, amines, and epoxies have excellent ink absorbency and are extremely water resistant. The inventors discovered that this is an ink dinit recording sheet with excellent properties and completed the present invention.

The present invention will be explained in more detail below.

Adding an acetoacetyl group, which is not used in the present invention,
It can be obtained by a method such as transesterification with acetoacetate. The content of acetoacetyl group is selected from the range of 1 to 20 mol %, preferably 0.5 to 10 mol %. Content of acetoacetyl group is 0
．． If it is less than 1 mol%, the effect of improving water resistance is low;
If it exceeds 0 mol%, the ink absorption speed will decrease. Moreover, the polymer box of the above-mentioned modified PVA is usually 100 to 30 fJU.
, preferably from the range of 500 to 20 υO, and the degree of saponification is not particularly limited as long as it is water-soluble, but is usually selected from the range of 70 to ILI (1 mol%, preferably 80 to 95 mol%).

Among the aldehydes, amines, and epoxies used in the present invention, examples of the aldehydes include monoaldehydes (i. Examples include dialdehydes such as aldehyde, maleic dialdehyde, phthaldialdehyde, and dialdehyde starch, and daryoxal is preferably used.

In addition, amines include urea, methylol urea, melamine, methylol melamine, hexamethylene diamine,
Preferred examples include triethanolamine, particularly methylolmelamine and methylolurea.

Examples of the epoxies include ethylene glycol cydalidyl ether, polyethylene glycol diglycidyl ether, glycerin di- or tridalicidyl ether, trimethylolpropane triglycidyl ether, 1
．． Examples include 6-hexanesiol diglycidyl ether.

The blending ratio of the above-mentioned modified 1'VA used in the present invention and at least one organic compound selected from aldehydes, amines, and epoxies is 1013/1- by weight.
100/20, preferably lυ0/2~1()0/10
selected from the range. The blending ratio of the above organic compounds is 1
In the following cases, the water resistance is not sufficient, and in the case of more than 20, the ink absorbency tends to decrease.

The modified 1'VA used in the present invention and the above-mentioned organic compounds may be used alone, but they may also be used in combination with other water-soluble resins, water-dispersible resins, water-soluble inorganic compounds, or inorganic fillers. It can also be used as

Other water-soluble or water-dispersible resins that can be used in combination include arbuvin, gelatin, casein, starch, gum arabic, cellulose conductors such as methyl cellulose and hydroxyethyl cellulose, polyamide resins, melamine resins, ordinary unmodified PVA, poly( Nonionic water-soluble resins such as methacoacrylamide and polyvinylpyrrolidone, eSle, sodium poly(meth)acrylate,
Anion-modified 1'VA, sulfur alginate, anionic water-soluble resin such as water-soluble polyester, polyethyleneimine, polyvinylamine, boria sulfuramine,
Boria dh l) Ruamine sulfone copolymer or small ammonium salt, cationized starch, cationized poly(methane acrylamide, cation-modified PVA,
Cationic water-soluble resins such as cationic polyamide resins,
Water-dispersible resins such as 5DI latex, NBlI latex, vinyl emulsion, ethylene/A1E acid vinyl copolymer emulsion, (meth)acrylic ester emulsion, and vinyl chloride emulsion are available.

When these water-soluble or water-dispersible resins are used in combination with the modified PVA used in the present invention and the above-mentioned organic compounds such as aldehydes, the ratio of the combined use is as follows: xuuf(
: Not more than i part, preferably not more than 50 parts by weight.

In addition, examples of water-soluble inorganic compounds that can be used in combination in the present invention include aluminum sulfate, potassium bright bread, ammonium bright bread, magnesium chloride, common salt chloride, ferric chloride, aluminum chloride, and the like. When these water-soluble inorganic compounds are used in combination, the amount is 0.5 to 10 parts by weight per 100 parts by weight of the above-mentioned modified PVA having acetoacetyl threads.
It is preferable to use within the range of parts by weight.

In addition, inorganic fillers that can be used in combination in the present invention include silica, clay, talc, cane earth, zeolite,
Examples include calcium carbonate, alumina, oxidized salts, and sachin white.1. Ru. In this case, the combination ratio differs depending on whether the recording sheet has high transparency or other cases, but the ratio of [modified 1'VA/filler] used in the present invention is usually from /100 to 100/1, preferably 5/10
It is selected from the range of 0 to too/s.

71. Selected from modified PVA having an acetoacetyl group used in the present invention, aldehydes, amines, and epoxies. A composition comprising at least one type of η-organic compound can be used as an ink-absorbing layer because it has excellent ink-absorbing properties itself, but it can also be used as an ink-absorbing layer on an ink-absorbing layer made of other ink-absorbing materials. It is also possible to form a layer made of the composition and use it as water-resistant I-.

As the transparent supporting substrate used in the present invention, any conventionally known transparent or opaque supporting substrate can be used. Examples of the transparent support substrate include films of polyester, polystyrene, polyvinyl chloride, polymethyl methacrylate, cellulose acetate, polycarbonate, polyimide, cellophane, celluloid, etc., C1-, R-1, or highly transparent paper. . As an opaque support substrate,
Examples include general paper, pigment-coated paper, cloth, wood, metal plates, synthetic paper, and opaquely treated synthetic resin films or sheets.

In the case of an inkjet recording sheet with excellent transparency, which is one of the objects of the present invention, a transparent support substrate is used.

In the present invention, the method of making the supporting substrate contain a composition consisting of the above-mentioned modified PVA having an acetoacetyl group and at least one organic compound selected from aldehydes, amines, and epoxies includes the above-mentioned method. An aqueous solution or aqueous dispersion of the composition or a mixture thereof with other water-soluble or water-dispersible resins, water-soluble inorganic compounds, or fillers is prepared using a size press, air knife coater, roll coater, bar coater, or blade coater. It can be impregnated into the supporting substrate by a conventional coating method, or a coating layer can be formed on the upper surface or both the upper and lower surfaces of the supporting substrate.

Furthermore, when the supporting substrate is paper, a method of internally adding the above-mentioned aqueous solution or aqueous dispersion during paper making can also be used.

Modified PV in the inkjet recording sheet of the present invention
There is no particular restriction on the content of the composition consisting of a and at least one organic compound selected from aldehydes, amines, and epoxies, but it is usually 0.1 to 200 y/l.
ri is preferably 1 to 1 (I09/K) is used.

81 Effects and Effects of the Invention The reason why the inkjet recording sheet of the present invention has excellent ink absorption properties and extremely excellent water resistance is not fully elucidated, but is presumed to be as follows.

Acetoacetyl group-modified PVΔ used in the present invention
and at least 1 pJi of an organic compound selected from aldehydes, amines, and epoxies is water-soluble before sebum formation and remains hydrophilic after film formation, but the resulting film is extremely water resistant. It is presumed that it is possible to form an inkjet recording sheet that has extremely excellent ink absorbency and water resistance because of its high properties.

The present invention will be explained in more detail with reference to Examples below.
The invention is not limited by this. In the examples, unless otherwise specified, "%" and "part"
represents weight basis.

The methods for measuring various physical properties in Examples are shown below.

(1) Inkjet Recording Method Color inkjet recording was performed using the following four colors of ink using a recording apparatus having an ondiant type inkjet recording head with an ejection orifice diameter of 60 μm, and the recording characteristics were evaluated.

Yellow ink (composition) C, 1, acid yellow 2, 3 2 parts diethylene glycol 30 parts water
70 parts Magenta ink (composition) 0, 1.7 Shredded 32 2 parts diethylene glycol 30 parts water
70 parts Cyan ink (composition) 0.1. Direct Blue 86 2 parts diethylene glycol 30 parts water
7 parts part black ink (composition) 0.1. Direct Black 19 2 parts diethylene glycol 30 parts water
After inkjet recording of 70 copies, the print on the recording sheet was rubbed with a finger at regular intervals, and the time until the print part stopped changing was measured. The shorter the time, the faster the ink absorption speed.

(3) Bleeding degree The diameter of the printed dot was measured using a stereomicroscope, and it was shown how many times larger it was than the ink droplet. The lower the magnification, the less blurring.

(4) Transparency The visible light transmittance of the non-printed portion of the inkjet recording sheet was measured using a spectrophotometer using visible light having a wavelength of 5 Utlnm. This transmittance is defined as transparency.

The higher the transmittance, the higher the transparency.

(5) Water resistance When the printed area of the sheet after inkjet recording was soaked in water and rubbed with a finger, judgment was made based on whether the printed area dissolved or smeared. 5: No change to l: Bleeding and dissolution.

Example 1 A 50 μm thick, transparent +19596 polyester sheet containing 6 mol% of acetoacetyl groups and a saponification degree of 8
A 10 rainwater solution containing 100 parts of modified PVA with 8 mol % and a degree of polymerization of 1000 and 5 parts of glyoxal was applied so that the coating amount after drying was 15 y/d and dried to obtain an inkjet recording sheet.

Table 1 shows the ink absorption speed, degree of bleeding, transparency, and water resistance of this sheet.

Comparative Examples 1 to 4 Comparative examples were carried out in the same manner as in Example 1 except that the following resins were used in place of the composition used in Example 1. The results are also shown in Table 1.

Resin used in Comparative Example 1: Modified PV used in Example 1
A only.

Resin used in Comparative Example 2; degree of polymerization 1000, degree of saponification 88
100 parts of mole% i'vΔ and 5 parts of glyoxal.

Resin used in Comparative Example 3: polyvinylpyrrolidone.

Resin used in Comparative Example 4: Cation-modified PV containing 2 mol% of cationic groups, a degree of polymerization of 1750, and a degree of saponification of 88 mol%
A.

Example 2 The composition used in Example 1 was applied onto the polyvinylpyrrolidone layer of the inkjet recording sheet obtained in Comparative Example 3 so that the dry solid content was 5 fib, and dried to perform inkjet recording. I got a sheet for it. The results are also shown in Table 1.

Example 3 The formulation used in Example 1 was applied onto the cation-modified PVA layer of the inkjet recording sheet obtained in Comparative Example 4 so that the dry surface Jl-9 min was 3 y//r11. It was dried to obtain an inkjet recording sheet. The results are also shown in Table 1.

The following is a margin: Table 1 Examples 4 to 1 The same procedure as in Example 1 was carried out except that art paper was used as the support substrate and modified PVa and organic compounds as shown in Table 2 were used. The results are also shown in Table 2.

Example 12 Using high-quality paper as a support substrate, a coating solution with the following composition using the composition used in Example was coated with a dry solid content of 20 y/
It was coated with a bar coater so as to give rrt and dried to obtain a recording sheet. The ink absorption speed of this sheet,
Table 3 shows the degree of bleeding and water resistance.

Comparative Example 5 The same procedure as Example 12 was carried out except that the composition used in Comparative Example 2 was replaced with the composition used in Example 12. The results are also shown in Table 3.

Example 13 Using high-quality paper as a supporting substrate, the composition used in Example 1 was coated so that the dry solid content was 5 y/rd and dried to obtain a recording sheet. The performance of this sheet is shown in Table 4.

Comparative Example 6 The same procedure as in Example 13 was carried out except that polyvinylpyrrolidone was used instead of the composition used in Example 13. The results are also shown in Table 4.

Table 4

Claims (2)

[Claims] (1) An inkjet with excellent water resistance characterized in that the supporting substrate contains modified polyvinyl alcohol having an acetoacetyl group and at least one organic compound selected from aldehydes, amines, and epoxies. Sheet for recording. (2) at least one organic compound selected from aldehydes, amines, and epoxies is glyoxal,
The sheet for inkjet recording according to claim 1, wherein the weight blending ratio is 1 to 20 parts by weight based on 100 parts by weight of the modified polyvinyl alcohol.