JP3053231B2 - Inkjet recording sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet having excellent ink absorbency and remarkably excellent water resistance.

[0002]

2. Description of the Related Art Ink jet recording systems are known as facsimile and overhead projector (hereinafter abbreviated as OHP) sheets because of their low noise, easy colorization, and high-speed recording.
Applications to various printers and the like are being promoted. Normally, paper has been used as a recording material used in the ink jet recording method.However, with the performance improvement of the recording sheet such as faster recording or multi-color recording, a more advanced paper than the ink jet recording sheet has been used. Characteristics are being demanded. That is, first, the ink absorption speed is high,
Secondly, the ink diameter after absorbing the ink-jet droplets does not become larger than necessary, and thirdly, the water resistance of the ink-jet recording sheet itself is high. In order to satisfy these requirements, various studies have been made to use paper or a water-soluble resin as an absorbent for a water-soluble inkjet ink. However, at present, when the ink absorption speed is increased, the ink dot diameter becomes larger than necessary and the water resistance is remarkably reduced.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording sheet which satisfies the above-mentioned required performance and is particularly excellent in ink absorbency and water resistance. Still another object of the present invention is to provide a transparency that can be used for observation by projecting a recorded image on a screen or the like by an optical device such as a slide or OPH, or that can be used for transmitted light observation such as a color display. An object of the present invention is to provide an excellent ink jet recording sheet.

[0004]

The present inventors have conducted intensive studies to solve the above problems, and as a result, the following formulas (I) and (I)
At least one monomer selected from I) and (III)
Or hydrolysis of copolymers of vinyl and vinyl esters
Polyvinyl alcohol (PVA) (A) having at least one functional group selected from a primary amino group, a primary ammonium group, a secondary amino group and a secondary ammonium group in a molecule obtained by the method and a polyhydric dialdehyde compound (B)
Consisting of 100 parts by weight of component (A) and component (B)
It has been found that an ink jet recording sheet having a composition in an amount of 1 to 50 parts by weight in a support substrate or on the surface of a support substrate is an ink jet recording sheet having excellent ink absorbency and extremely excellent water resistance. The invention has been completed. .

[0005]

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[0006]

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[0007]

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(Where R ¹ is a hydrogen atom or a methyl group, R ² is a hydrogen atom or a lower alkyl group, R ³ is a hydrogen atom, a lower alkyl group, a methylol group or an ethylol group, n is an integer of 0-4, m shows the integer of 2-4, respectively.)

Hereinafter, the present invention will be described in detail. PVA having at least one functional group selected from a primary amino group, a primary ammonium base, a secondary amino group and a secondary ammonium group in the molecule used in the present invention
(A) is represented by the above formula (I), (II) or (III)
That it is obtained by saponifying or hydrolyzing a copolymer of a monomer with a vinyl ester. The average degree of polymerization of PVA (A) is usually 100 to 5,000, preferably 200 to 2,000.
Selected from 500. The average degree of polymerization of PVA (A) is 10
If it is less than 0, the performance as a binder, particularly the physical properties of the film, is insufficient. If it exceeds 5,000, the solution viscosity becomes too high, which is not preferable in view of workability. The average degree of saponification of PVA (A) is preferably from 60 to 100 mol%. PVA (A)
If the average degree of saponification is less than 60 mol%, it is not preferable because it becomes difficult to dissolve in water. The content of the primary amino group, primary ammonium group, secondary amino group or secondary ammonium group in the PVA (A) is not particularly limited as long as it is 0.05 mol% or more, but is usually 0.1 to 0.1 mol%. It is selected from the range of 30 mol%, and preferably 0.5 to 10 mol%. When the content of the amino group or the ammonium base is 0.05
When the amount is less than mol%, it is difficult to improve the ink absorbency and the water resistance of the ink jet recording sheet of the present invention, and when the amount exceeds 30 mol%, the ink absorption speed decreases. It is not preferable.

As the monomer represented by the above formula (I),
Is a salt of vinylamine or an organic or inorganic acid thereof, a monomer represented by the formula (II) is N-vinylamide, and a monomer represented by the formula (III) is N-vinylimide. No.

As a catalyst for hydrolyzing the above copolymer, an acid or an alkali can be used. When an acid catalyst is used, the amino group formed by hydrolysis of the amide group in the unit composed of the monomer represented by the above formula (II) or (III) is reacted with the acid catalyst to form an ammonium group. It can be a base. When an alkali catalyst is used, an amino group can be generated by hydrolysis of the amide group, and the amino group can be converted to an ammonium base by reacting the amino group with an acid. In addition, among PVAs (A) containing the amino group or the ammonium, PVA having a primary amino group or a primary ammonium group in the molecule is preferable in terms of ink absorption and water resistance.

Polyhydric dialdehyde compound used in the present invention
Examples of the product (B) include polyhydric aldehyde compounds such as glyoxal, glutaraldehyde, and dialdehyde starch. Above all, when the dialdehyde compound is added as a waterproofing agent to a coating solution containing PVA having the amino group or the ammonium group as a water-resistant agent, the viscosity over time is extremely small,
It is particularly preferably used because deterioration of the water-resistant agent due to a side reaction with water is small.

The PVA (A) of the present invention and a polyvalent dialdehyde
The compounding ratio of the compound (B) is such that 100 parts by weight of the component (A) (hereinafter, part by weight is abbreviated as “parts”) and 1 part of the component (B)
To 50 parts, preferably 2 to 20 parts of component (B) based on 100 parts of component (A). When the amount of the component (A) is less than 1 part, the effect of imparting water resistance is not exhibited, and when the amount exceeds 50 parts, the ink absorption rate is lowered and the viscosity stability of the coating liquid is unfavorably deteriorated. PVA having the amino group or the ammonium base used in the present invention
(A) and polyhydric dialdehyde compound (B) is used in combination it can also be used in their only, other water-soluble resins, water dispersible resins, and water-soluble inorganic compound or inorganic filler
It is also possible to.

Other water-soluble or water-dispersible resins that can be used in combination include albumin, gelatin, casein, starch, gum arabic, cellulose derivatives such as methylcellulose, hydroxyethylcellulose, polyamide resins, melamine resins, ordinary unmodified PVA, (Meta)
Nonionic water-soluble resins such as acrylamide and polyvinylpyrrolidone, CMC, anionic water-soluble resins such as sodium poly (meth) acrylate, anion-modified PVA, sodium alginate, water-soluble polyester, cationized starch, cationized poly (meth) Cationic water-soluble resin such as acrylamide, cation-modified PVA, cationized polyamide resin, SBR latex, NBR latex, vinyl acetate emulsion, ethylene-vinyl acetate copolymer emulsion, (meth) acrylate emulsion, vinyl chloride Water-dispersible resins such as emulsions can be used. These water-soluble or water-dispersible resins are used in combination with the PVA (A) used in the present invention and the polyvalent dial.
When used in combination with the aldehyde compound (B), the combination ratio is 100 parts by weight with respect to 100 parts by weight of the PVA (A) of the present invention.
Parts or less, preferably 50 parts or less.

The water-soluble inorganic compounds which can be used in combination in the present invention include aluminum sulfate, potassium ash, ammonium ash, magnesium chloride, zinc chloride, and secondary chloride.
Iron, aluminum chloride and the like. When these water-soluble inorganic compounds are used in combination, the above-mentioned PVA (A) 1
It is preferable to use 0.5 to 10 parts with respect to 00 parts. Examples of the inorganic filler that can be used in the present invention include silica, clay, talc, diatomaceous earth, zeolite, calcium carbonate, alumina, zinc oxide, and satin white. In this case,
The recording sheet for inkjet which requires transparency is different from the other cases, but the PV sheet usually used in the present invention is
0.1 to 10,000 parts per 100 parts by weight of A (A),
Preferably it is selected from the range of 5 to 2000 parts.

A primary amino group used in the present invention,
A composition comprising PVA (A) having at least one functional group selected from a primary ammonium base, a secondary amino group and a secondary ammonium base and a polyvalent dialdehyde compound (B) has an ink absorbing property by itself. Because of its excellent properties, it can be used as an ink-absorbing layer by forming a composition layer on the surface of a supporting substrate.However, a layer made of the composition of the present invention is formed on an ink-absorbing layer made of another ink-absorbing material. It can also be used as a water-resistant layer. Further, the composition of the present invention may be used by impregnating it in a supporting substrate.

As the support substrate used in the present invention, any of transparent or opaque conventionally known support substrates can be used. Examples of the transparent support substrate include films, sheets, and highly transparent papers such as polyester, polyamide, polystyrene, polyvinyl chloride, polymethyl methacrylate, cellulose acetate, polycarbonate, polyimide, cellophane, and celluloid. Examples of the opaque support include general paper, coated paper, cloth, wood, metal plate, synthetic paper, opaque-treated synthetic resin film or sheet, and the like. In the case of an ink jet recording sheet having excellent transparency, which is one of the objects of the present invention, a transparent support substrate is used. In the present invention, a PV having at least one functional group selected from the above-mentioned primary amino group, primary ammonium group, secondary amino group and secondary ammonium group on the supporting substrate
As a method for giving a composition comprising A (A) and a polyvalent dialdehyde compound (B), an aqueous solution of the composition alone, or a composition and another water-soluble resin, a water-dispersible resin, a water-soluble inorganic compound, Alternatively, an aqueous solution or aqueous dispersion of a mixture with a filler is impregnated into a support substrate by a usual coating method such as a size press, an air knife coater, a roll coater, a bar coater, a blade coater, or the like, or the upper surface of the support substrate A method of forming a coat layer on both the surface and the lower surface can be used. When the supporting substrate is paper, a method of internally adding the above aqueous solution or aqueous dispersion during papermaking can also be used.
The PVA in the ink jet recording sheet of the present invention
The content of the composition comprising (A) and the polyvalent dialdehyde compound (B) is not particularly limited, but is usually 0.1 to 20.
0 g / m ² , preferably 1 to 100 g / m ² .

[0018]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In the examples, unless otherwise specified, "%"
And "part" represents a basis of weight. The methods for measuring various physical properties in the examples are shown below. (1) Inkjet recording method Using a recording apparatus having an on-demand type inkjet recording head having a discharge orifice diameter of 60 μm, yellow,
Color ink jet recording was performed using four-color aqueous inks of magenta, cyan, and black, and recording characteristics were evaluated. (2) Ink absorption speed After ink jet recording, the print on the recording sheet was rubbed with a finger at regular intervals, and the time until the printed portion did not change was measured. The shorter the time, the higher the ink absorption speed. (3) Bleeding degree The direct line of the printing dot was measured by a stereoscopic microscope, and the number of times the ink droplet became larger was shown. (4) Transparency The visible light transmittance (%) of the non-printed portion of the inkjet recording sheet was measured with a spectrophotometer using visible light having a wavelength of 500 nm. The transmittance is defined as the transparency. The higher the transmittance, the higher the transparency. (5) Water Resistance When water was applied to the printed portion of the sheet after inkjet recording and the finger was rubbed with the finger, it was determined in five stages whether the printed portion was dissolved or bleed. 5: No change. 1: There is bleeding or dissolution. 4-2: Middle of 5-1 (larger numbers have less bleeding or change).

EXAMPLE 1 A copolymer of N-vinylacetamide and vinyl acetate was alkali-saponified to contain 5 mol% of primary amino groups, a degree of saponification of vinyl acetate units of 92.5 mol%, and a degree of polymerization of 1100
A modified PVA having a primary amino group in the molecule was obtained. On a 50 μm thick, 95% transparent polyester sheet,
A 10% aqueous solution containing 100 parts of the primary amino group-modified PVA and 5 parts of glyoxal as a water-proofing agent is applied so that the coating amount after drying is 15 g / m ² , and dried,
An ink jet recording sheet was obtained. The ink absorption rate, bleeding degree, transparency, and water resistance of this sheet were evaluated, and the results are shown in Table 1.

Example 2 N-vinylacetamide used in Example 1 was replaced by N
-Using vinyl succinimide, copolymerized with vinyl acetate, and saponified with alkali to prepare a primary amino group-modified PVA. This modified PVA contained 7 mol% of primary amino groups, had a saponification degree of vinyl acetate units of 88.2 mol% and a polymerization degree of 1050. Example 1 was repeated except that the above-mentioned modified PVA was used in place of the modified PVA used in Example 1 and glutaraldehyde was used instead of glyoxal.
In the same manner as in the above, an ink jet recording sheet was prepared. The evaluation results are also shown in Table 1.

Comparative Examples 1 to 3 The same procedures as in Example 1 were carried out except that the following resin and water-proofing agent were used instead of the composition used in Example 1. The results are shown in Table 1. Resin and waterproofing agent used in Comparative Example 1: degree of polymerization 100
0, 100 parts of unmodified PVA having a saponification degree of 88 mol% and 5 parts of guoxal. Resin used in Comparative Example 2 (waterproofing agent was not used): polyvinylpyrrolidone (PVP). Resin and water-proofing agent used in Comparative Example 3: 100 parts of cation-modified PVA containing 2 mol% of a quaternary ammonium base, having a polymerization degree of 1750 and a saponification degree of 88 mol%, and 5 parts of glyoxal.

Example 3 With respect to the ink jet recording sheet obtained in Comparative Example 3, the composition used in Example 1 was dried on a layer containing a composition comprising quaternary ammonium base-modified PVA and glyoxal. The composition was applied so that the solid content was 3 g / m ^2, and dried to obtain an ink jet recording sheet. The results are shown in Table 1.

Example 4 A coating liquid consisting of 25 parts of the composition used in Example 1, 100 parts of non-colloidal silica powder and 500 parts of water was applied to a high quality paper so that the dry solid content was 17 g / m ^2. It was applied with a coater and dried to obtain a recording sheet. The results are shown in Table 1.

[0024]

[Table 1]

[0025]

The ink jet recording sheet of the present invention has excellent ink absorbency and excellent physical properties such as remarkably excellent water resistance. The reason for this is not fully understood,
It is estimated as follows. PVA (A) having at least one functional group selected from a primary amino group, a primary ammonium group, a secondary amino group, and a secondary ammonium group in the molecule used in the present invention is an aqueous ink used for ink jet or the like. because of the greater affinity with a multi
Shows the valence dialdehyde compound (B) and the ink absorption performance of the coating also excellent after the crosslinking reaction has been performed, also polyhydric dialkyl
It is presumed that it has excellent water resistance because of its high reactivity with the aldehyde compound . These effects cannot be obtained with unmodified PVA or modified PVA containing a quaternary ammonium base, which is a conventional cation-modified PVA. Table
As is clear from FIG. 1, the ink bleeding was small and
A transparent substrate is used, and the above (A) and
When the composition of (B) is coated, the transparency is
Inkjet with excellent transparency without loss
A recording sheet is obtained.

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI C09D 129/04 C09D 129/04 (56) References JP-A-1-159286 (JP, A) JP-A-63-315283 (JP, A) JP-A-1-15784 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/00 C08F 8/12 C08F 8/30 C08L 29/04 C09D 129/04

Claims (3)

(57) [Claims] (1) From the following formulas (I), (II) and (III)
Of at least one selected monomer and vinyl ester
A polyvinyl alcohol (A) having at least one functional group selected from a primary amino group, a primary ammonium group, a secondary amino group and a secondary ammonium group in a molecule obtained by saponifying or hydrolyzing the copolymer; Multivalent
An ink jet recording sheet comprising a composition comprising the aldehyde compound (B) and 1 to 50 parts by weight of the component (B) based on 100 parts by weight of the component (A) in the support substrate or on the surface of the support substrate. Embedded image Embedded image Embedded image (Where R ¹ is a hydrogen atom or a methyl group, R ² is a hydrogen atom
R ³ is a hydrogen atom, lower alkyl,
Group, a methylol group or ethylol group, n represents 0-4 of
Integer and m each represent an integer of 2 to 4. ) 2. The ink jet recording sheet according to claim 1, wherein the functional group is a primary amino group or a primary ammonium base. 3. The support substrate according to claim 1, wherein the support substrate is a transparent support substrate.
3. The recording sheet for inkjet according to 1 or 2.