JP4369828B2 - Inkjet recording material - Google Patents

Description

  The present invention relates to a recording material for an ink jet printer, and relates to a recording material excellent in printability of a solvent-based ink, particularly a glycol-based ink.

  Conventionally, so-called water-based inks using water and lower alcohol as solvents have been mainstream as inks for inkjet recording. For this reason, many recording materials having an ink receiving layer mainly composed of a water-soluble resin have been developed.

  However, there is a problem that water-based ink is inferior in water resistance. In recent years, therefore, models using solvent-based inks such as paraffin-based inks and thinner-based inks have started to appear.

  However, although these solvent-based inks are excellent in water resistance, paraffin-based inks have a drawback that they easily damage recording materials and protective films. In addition, the thinner ink has a problem that it has a strong odor, has a large influence on the environment, and is dangerous, and therefore requires a person with a specific qualification when handling it.

  Therefore, glycol-based inks mainly composed of glycol ether and alkylene glycol have been developed. This ink is a newly developed solvent-based ink, which is excellent in water resistance and eliminates the above-mentioned drawbacks of conventional solvent-based inks.

  As the ink jet recording material for glycol ink, other ink jet recording materials for solvent ink can also be used. Examples of the solvent-based inkjet recording material include a material having an ink receiving layer containing a polyvinyl acetal resin such as polyvinyl butyral on a substrate. However, such an ink jet recording material does not have sufficient adhesion between the substrate and the ink receiving layer and ink drying.

Therefore, as an ink jet recording material having improved adhesion between the base material and the ink receiving layer, a material having an ink receiving layer containing a polyvinyl butyral resin and a urethane resin on the base material has been proposed (patent) Reference 1). However, such an ink jet recording material has improved adhesiveness, but has to increase the proportion other than the polyvinyl butyral resin, thereby impairing recording suitability such as ink drying properties. .
JP 2004-122365 A (Claim 1)

  The present invention has been made in view of the above circumstances, and provides an ink jet recording material that is excellent in printability such as ink drying property for solvent-based inks, particularly glycol-based inks, and is excellent in adhesion to a substrate. For the purpose.

  Therefore, as a result of intensive studies to solve the above-mentioned problems, the present inventors have solved this problem.

  That is, the ink jet recording material of the present invention has an ink receiving layer containing a polyvinyl acetal resin on a synthetic resin film, and is formed of acrylic acid or hydroxyalkyl acrylate between the synthetic resin film and the ink receiving layer. It has an undercoat layer containing a copolymer composed of at least one selected from vinyl chloride and vinyl acetate.

Preferably, the composition of the copolymer is such that the composition ratio of vinyl chloride is 58 to 98% by weight, the composition ratio of vinyl acetate is 1 to 40% by weight, and the total composition ratio of acrylic acid and hydroxyalkyl acrylate is 0.3 to 0.3%. It is characterized by being 20% by weight .

  The ink jet recording material of the present invention comprises a polyvinyl acetal resin in an ink receiving layer, and at least one selected from vinyl alcohol, acrylic acid and hydroxyalkyl acrylate, vinyl chloride and vinyl acetate between the substrate and the ink receiving layer. Since it has an undercoat layer containing a copolymer consisting of the above, it is excellent in printability such as ink drying properties for solvent-based inks, especially glycol-based inks, and also excellent in adhesion between the substrate and the ink receiving layer It is.

  The ink jet recording material of the present invention has an ink receiving layer containing a polyvinyl acetal resin on a synthetic resin film, and is selected from acrylic acid and hydroxyalkyl acrylate between the synthetic resin film and the ink receiving layer. It has an undercoat layer containing a copolymer composed of at least one kind and vinyl chloride and vinyl acetate. Hereinafter, embodiments of each component will be described.

  As the synthetic resin film, various synthetic resin films made of polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polyvinyl chloride, polyethylene naphthalate, polystyrene, (meth) acrylic ester resin, fluorine resin, and the like can be used. The thickness of the synthetic resin film is not particularly limited, but is preferably 5 μm or more in terms of conveyance.

  The ink jet recording material of the present invention improves the adhesion between the synthetic resin film and the ink receiving layer by the undercoat layer described later, but the surface of the synthetic resin film is better for better adhesion. It is preferable that an easy adhesion treatment is performed.

  Examples of the easy adhesion treatment include plasma treatment, corona discharge treatment, far ultraviolet irradiation treatment, and formation of an easy adhesion layer. The easy adhesion layer is formed from a polyester resin, an acrylic resin, or the like. Among these, the easy-adhesion layer which consists of a mixed system of a polyester resin and an acrylic resin is preferable at the point which is excellent in adhesiveness with the undercoat layer mentioned later.

  The resin constituting the ink receiving layer is mainly a polyvinyl acetal resin. The polyvinyl acetal resin is excellent in printability for solvent-based inks, particularly glycol-based inks.

  As the polyvinyl acetal resin, known polyvinyl acetal resins such as a polyvinyl formal resin, a polyvinyl acetoacetal resin, a polyvinyl butyral resin, and an aromatic polyvinyl acetal resin can be used alone or in combination.

  The polyvinyl acetal resin is preferably used in combination with a polyvinyl acetal resin having a glass transition temperature of 75 ° C. or lower and a polyvinyl acetal resin having a glass transition temperature of 80 ° C. or higher. By including these two types of polyvinyl acetal resins in the ink-receiving layer, the ink-drying property and anti-bleeding property for solvent-based inks, particularly glycol-based inks in particular, are improved, and pigment cracking is also prevented. Good aptitude can be obtained.

  The polyvinyl acetal resin can be produced by acetalizing polyvinyl alcohol with aldevid, and at this time, by appropriately adjusting the polymerization degree of polyvinyl alcohol as a raw material, the type of aldehyde, and the degree of acetalization, a glass transition temperature is obtained. A polyvinyl acetal resin having a temperature of 75 ° C. or lower and a polyvinyl acetal resin having a glass transition temperature of 80 ° C. or higher can be obtained.

  As the polyvinyl acetal resin having a glass transition temperature of 75 ° C. or lower, any polyvinyl acetal resin such as polyvinyl formal resin, polyvinyl acetoacetal resin, polyvinyl butyral resin, and aromatic polyvinyl acetal resin can be used. These polyvinyl acetal resins preferably have a glass transition temperature of 70 ° C. or lower. Moreover, it is preferable that the minimum of glass transition temperature is 50 degreeC or more from a viewpoint of preventing blocking. Among these polyvinyl acetal resins, a polyvinyl butyral resin excellent in bleeding resistance is preferably used.

  The polyvinyl acetal resin having a glass transition temperature of 75 ° C. or less preferably has a degree of acetalization of 50 mol% or more, and more preferably 70 mol% or more. By setting the degree of acetalization to 50 mol% or more, the ink drying property and bleeding prevention property can be further improved, and pigment cracking can also be prevented.

The polyvinyl acetal resin having a glass transition temperature of 75 ° C. or less preferably has a weight average molecular weight (Mw) of 3.0 × 10 ^{4 to} 7.0 × 10 ⁴ , preferably 4.0 × 10 ^{4 to} 6.0 × 10 ^4. More preferred. By setting the weight average molecular weight to 3.0 × 10 ⁴ or more, ink drying properties can be improved and pigment cracking can be prevented. By setting the weight average molecular weight to 7.0 × 10 ⁴ or less, a glass transition temperature of 80 Compatibility with a polyvinyl acetal resin having a temperature of at least ° C. can be improved.

  As the polyvinyl acetal resin having a glass transition temperature of 80 ° C. or higher, any polyvinyl acetal resin such as polyvinyl formal resin, polyvinyl acetoacetal resin, polyvinyl butyral resin, and aromatic polyvinyl acetal resin can be used. These polyvinyl acetal resins preferably have a glass transition temperature of 100 ° C. or higher. The upper limit of the glass transition temperature is preferably 150 ° C. or lower from the viewpoint of preventing curling of the ink jet recording material. Among these polyvinyl acetal resins, polyvinyl acetoacetal resins that can achieve better ink drying properties are preferably used.

  The polyvinyl acetal resin having a glass transition temperature of 80 ° C. or more preferably has a degree of acetalization of 50 mol% or more, and more preferably 70 mol% or more. By setting the degree of acetalization to 50 mol% or more, it is possible to further improve the ink drying property and bleeding prevention property and to easily prevent pigment cracking.

The polyvinyl acetal resin having a glass transition temperature of 80 ° C. or higher is preferably a weight average molecular weight (Mw) of 3.0 × 10 ⁴ or less, and more preferably 2.0 × 10 ⁴ or less. Further, the lower limit of the weight average molecular weight (Mw) is preferably 1.0 × 10 ⁴ or more. By setting the weight average molecular weight to 3.0 × 10 ⁴ or less, compatibility with a polyvinyl acetal resin having a glass transition temperature of 75 ° C. or less can be improved.

  A resin other than the polyvinyl acetal resin may be contained in the ink receiving layer. Examples of such resins include vinyl resins and alkyd resins. However, the content of the polyvinyl acetal resin in the ink receiving layer is preferably 50% by weight or more, more preferably 90% by weight or more in the total resin constituting the ink receiving layer.

  When using two types of resins, a polyvinyl acetal resin having a glass transition temperature of 75 ° C. or lower and a polyvinyl acetal resin having a glass transition temperature of 80 ° C. or higher, the glass transition is performed with respect to 100 parts by weight of the polyvinyl acetal resin having a glass transition temperature of 75 ° C. or lower. It is preferable to contain 5-70 weight part of polyvinyl acetal resin of temperature 80 degreeC or more, and it is more preferable to contain 10-40 weight part. By making it 70 parts by weight or less, the compatibility of the two kinds of resins can be improved, and pigment cracking can be prevented, and by making it 5 parts by weight or more, the ink drying property is made good. Can do.

  The polyvinyl acetal resin in the ink receiving layer may be crosslinked and cured with a phenol resin, an epoxy resin, a melamine resin, an isocyanate compound, a dialdehyde compound, or the like. By crosslinking and curing, the water resistance and chemical resistance of the ink jet recording material can be improved. In particular, by using a soft isocyanate compound having a glycol structure at the cross-linking portion, the flexibility of the ink receiving layer can be maintained while the ink receiving layer is crosslinked and cured, and pigment cracking can be prevented.

  The ink receiving layer may contain a pigment in order to improve ink absorbability or prevent blocking. In addition to inorganic pigments such as silica, clay, talc, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, titanium oxide, synthetic zeolite, alumina, smectite, styrene resin, urethane resin, benzoguanamine resin, silicone resin, Organic pigments such as resin beads made of acrylic resin or the like, or hollow resin beads made from these are used, and these can be used alone or in combination of two or more. The addition amount of the pigment is usually about 0.1 to 200 parts by weight with respect to 100 parts by weight of the total resin of the ink receiving layer.

  The thickness of the ink receiving layer is preferably 5 to 70 μm. When the thickness is 5 μm or more, ink absorbability can be improved, and when the thickness is 70 μm or less, curling can be prevented.

  The undercoat layer contains a copolymer (hereinafter sometimes referred to as “copolymer of the present invention”) comprising at least one selected from vinyl alcohol, acrylic acid, and hydroxyalkyl acrylate, and vinyl chloride and vinyl acetate. It is a waste. The copolymer of the present invention may contain at least one of vinyl alcohol, acrylic acid, and hydroxyalkyl acrylate as a copolymer component, and may contain two or more of these. . By setting the undercoat layer to such a configuration, the adhesion between the synthetic resin film and the ink receiving layer can be improved. Furthermore, the undercoat layer of the present invention is extremely advantageous in that it not only improves the adhesion between the synthetic resin film and the ink receiving layer, but also supplements the ink absorbability of the ink receiving layer and improves the ink drying property. Useful.

  In the present invention, the reason why the adhesiveness between the synthetic resin film and the ink receiving layer can be improved by configuring the undercoat layer as described above is a copolymer component other than vinyl chloride and vinyl acetate. This is presumably because the components vinyl alcohol, acrylic acid, and hydroxyalkyl acrylate are strongly bound to the polyvinyl acetal resin of the ink receiving layer, and vinyl chloride and vinyl acetate are firmly bound to the synthetic resin film. In addition, it is considered that the reason why the ink drying property can be improved is that vinyl chloride and vinyl acetate supplement the ink absorptivity.

  Here, it is considered that the same effect as that of the present invention can be obtained by mixing a resin obtained by polymerizing only vinyl alcohol, acrylic acid and hydroxyalkyl acrylate with a copolymer consisting only of vinyl chloride and vinyl acetate. However, it is difficult to form an undercoat layer because a resin obtained by polymerizing only vinyl alcohol, acrylic acid, and hydroxyalkyl acrylate is not compatible with a copolymer consisting only of vinyl chloride and vinyl acetate.

  In addition, since vinyl chloride and vinyl acetate are firmly bonded to the synthetic resin film and have a role of improving ink drying properties, if a vinyl chloride-vinyl acetate copolymer is contained in the ink receiving layer, It is considered that the same effect can be obtained. However, polyvinyl acetal resin and vinyl chloride-vinyl acetate copolymer are poorly compatible, making it difficult to form an ink receiving layer, and vinyl chloride-vinyl acetate copolymer reduces the excellent printability of polyvinyl acetal resin. I will let you.

  The composition ratio of vinyl chloride in the copolymer of the present invention is preferably 58 to 98% by weight, and more preferably 68 to 98% by weight. By setting it as such a range, while being able to make the adhesiveness of a subbing layer and a synthetic resin film favorable, ink dryness can be made favorable.

  The composition ratio of vinyl acetate in the copolymer of the present invention is preferably 1 to 40% by weight, and more preferably 1 to 30% by weight. By setting it as such a range, the adhesiveness of an undercoat layer and a synthetic resin film can be made favorable.

  The total composition ratio of vinyl alcohol, acrylic acid and hydroxyalkyl acrylate in the copolymer of the present invention is preferably 0.3 to 20% by weight. By setting it as such a range, the adhesiveness of an undercoat layer and an ink receiving layer can be made favorable.

The copolymer of the present invention preferably has a weight average molecular weight of 2.0 × 10 ⁴ or more. By setting the weight average molecular weight to 2.0 × 10 ⁴ or more, it is possible to prevent cohesive failure of the undercoat layer and to prevent the adhesiveness between the synthetic resin film and the ink receiving layer from being lowered.

  A resin other than the copolymer of the present invention may be contained in the undercoat layer. Examples of such resins include urethane resins and acrylic resins. However, the content of the copolymer of the present invention in the undercoat layer is preferably contained in an amount of 50 to 100% by weight in the total resin constituting the ink receiving layer.

  The thickness of the undercoat layer is not particularly limited, but the lower limit is preferably 0.01 μm or more, and more preferably 1 μm or more. By setting it as 0.01 micrometer or more, the adhesiveness of a synthetic resin film and an ink receiving layer can be made favorable, and by making it 1 micrometer or more, ink drying property can be made more favorable. . The upper limit of the thickness of the undercoat layer is preferably 3 μm or less. When the thickness is 3 μm or less, discoloration of the ink receiving layer can be prevented.

  The copolymer of the present invention in the undercoat layer may be crosslinked and cured with a phenol resin, an epoxy resin, a melamine resin, an isocyanate compound, a dialdehyde compound, or the like. By crosslinking and curing, the adhesiveness between the synthetic resin film and the ink receiving layer can be further strengthened, and the water resistance and chemical resistance of the undercoat layer can be improved. In particular, by using a soft isocyanate compound having a glycol structure in the cross-linked portion, the undercoat layer can be kept flexible while being crosslinked and cured.

  In the ink receiving layer and the undercoat layer, additives such as a leveling agent, an ultraviolet absorber, an antioxidant, and a chelating agent may be added.

  As a method for forming the ink receiving layer and the undercoat layer, a coating solution is prepared by dissolving or dispersing the components of each layer in an appropriate solvent, and the coating solution is roll coating, bar coating, spray coating, The method of apply | coating and drying on a support body by well-known methods, such as an air knife coating method, is mention | raise | lifted.

  In order to prevent the occurrence of curling, a back coat layer is provided on the surface of the support opposite to the ink receiving layer, or to prevent charging, the ink receiving layer is opposite to the ink receiving layer of the support or the support. It is possible to provide an antistatic layer on the side surface.

  The following examples further illustrate the present invention. “Parts” and “%” are based on weight unless otherwise specified. The composition ratio of the copolymer component of the copolymer is a weight ratio.

[Reference Example 1]
On a synthetic resin film (Lumirror U35: Toray Industries, Inc.) having a thickness of 100 μm, an undercoat layer coating solution having the following composition was applied by a bar coating method so that the thickness after drying was 2 μm, and dried at 120 ° C. for 3 minutes. As a result, an undercoat layer was formed. Then, an ink receiving layer coating solution having the following composition to a thickness after drying by bar coating so as to 30 [mu] m, and dried for 3 minutes at 120 ° C. to form an ink-receiving layer, in Reference Example 1 ink jet recording Obtained material.

<Undercoat layer coating solution>
-10 parts of vinyl chloride-vinyl acetate-vinyl alcohol terpolymer (vinyl chloride: vinyl acetate: vinyl alcohol = 92: 3: 5)
(Weight average molecular weight 3.0 × 10 ⁴ )
・ Methyl ethyl ketone 45 parts ・ Toluene 45 parts

<Ink-receiving layer coating solution>
・ 18 parts of polyvinyl butyral resin (ESREC BM-S: Sekisui Chemical Co., Ltd., glass transition temperature 60 ° C.,
(Weight average molecular weight 5.3 × 10 ⁴ , degree of acetalization 73 mol%)
-Polyvinylacetoacetal resin 2 parts (ESREC KS-10: Sekisui Chemical Co., Ltd., glass transition temperature 106 ° C,
(Weight average molecular weight 1.7 × 10 ⁴ , degree of acetalization 74 mol%)
・ Isocyanate compound 0.5 parts (MT-Olestar NP1200: Mitsui Takeda Chemical Co., solid content 70%)
・ Methyl ethyl ketone 40 parts ・ Toluene 40 parts

[Reference Example 2]
The terpolymer of the undercoat layer coating solution of Reference Example 1 was converted into vinyl chloride-vinyl acetate-vinyl alcohol terpolymer (vinyl chloride: vinyl acetate: vinyl alcohol = 87: 1: 12, weight average molecular weight 2 0.0 × 10 ⁴ ) An ink jet recording material was obtained in the same manner as in Reference Example 1 except that it was changed.

[Reference Example 3]
The terpolymer of the undercoat layer coating solution of Reference Example 1 was converted into vinyl chloride-vinyl acetate-vinyl alcohol terpolymer (vinyl chloride: vinyl acetate: vinyl alcohol = 87: 1: 12, weight average molecular weight 2 0.0 × 10 ⁴ ) An ink jet recording material was obtained in the same manner as in Reference Example 1 except that it was changed.

[Example 4]
The ternary copolymer of the undercoat layer coating solution of Reference Example 1 was converted into vinyl chloride-vinyl acetate-acrylic acid terpolymer (vinyl chloride: vinyl acetate: acrylic acid = 90: 7: 3, weight average molecular weight 3 An ink jet recording material was obtained in the same manner as in Reference Example 1 except that it was changed to 3 × 10 ⁴ ).

[Example 5]
The terpolymer of the undercoat layer coating solution in Reference Example 1 was converted into a vinyl chloride-vinyl acetate-hydroxyalkyl acrylate terpolymer (vinyl chloride: vinyl acetate: hydroxyalkyl acrylate = 81: 4: 15, weight average). An ink jet recording material was obtained in the same manner as in Reference Example 1 except that the molecular weight was changed to 2.4 × 10 ⁴ ).

[Comparative Example 1]
An inkjet recording material of Comparative Example 1 was obtained in the same manner as Reference Example 1 except that the ink receiving layer was directly formed without forming the undercoat layer.

[Comparative Example 2]
On the same synthetic resin film as in Reference Example 1, the undercoat layer coating solution of Reference Example 1 was applied by a bar coating method so that the thickness after drying was 30 μm, and dried at 120 ° C. for 3 minutes. As a result, the ink receiving layer was used as an ink receiving layer, and an ink jet recording material of Comparative Example 2 was obtained.

[Comparative Example 3]
Except for changing the ternary copolymer of the undercoat layer coating solution of Reference Example 1 to vinyl chloride-vinyl acetate copolymer (vinyl chloride: vinyl acetate = 75: 25, weight average molecular weight 2.6 × 10 ⁴ ). Obtained an ink jet recording material of Comparative Example 3 in the same manner as in Reference Example 1.

[Comparative Example 4]
Other than changing the ternary copolymer of the undercoat layer coating solution of Reference Example 1 to vinyl chloride-vinyl acetate copolymer (vinyl chloride: vinyl acetate = 89: 11, weight average molecular weight 4.2 × 10 ⁴ ) Obtained an ink jet recording material of Comparative Example 4 in the same manner as in Reference Example 1.

[Comparative Example 5]
The terpolymer of the undercoat layer coating solution of Reference Example 1 was converted into vinyl chloride-vinyl acetate-maleic acid terpolymer (vinyl chloride: vinyl acetate: maleic acid = 83: 16: 1, weight average molecular weight 2). The ink jet recording material of Comparative Example 5 was obtained in the same manner as in Reference Example 1 except that it was changed to 1 × 10 ⁴ ).

[Comparative Example 6]
Comparison was made in the same manner as in Reference Example 1 except that the terpolymer of the undercoat layer coating solution in Reference Example 1 was changed to a polyester resin (Byron 200: Toyobo Co., Ltd., weight average molecular weight 1.7 × 10 ⁴ ). The ink jet recording material of Example 6 was obtained.

[Comparative Example 7]
Comparison was made in the same manner as in Reference Example 1 except that the terpolymer of the undercoat layer coating solution in Reference Example 1 was changed to an acrylic resin (M1002B: Soken Chemical Co., Ltd., weight average molecular weight 4.25 × 10 ⁵ ). The ink jet recording material of Example 7 was obtained.

[Comparative Example 8]
An inkjet recording material of Comparative Example 8 was obtained in the same manner as in Reference Example 1 except that the undercoat layer coating solution of Reference Example 1 was changed to the following formulation.

<Undercoat layer coating solution>
・ 25 parts of urethane resin emulsion (Superflex 860: Daiichi Kogyo Seiyaku Co., Ltd., solid content 40%)
・ 75 parts of water

[Comparative Example 9]
An ink jet recording material of Comparative Example 9 was obtained in the same manner as in Reference Example 1, except that the undercoat layer coating solution of Reference Example 1 was changed to the following formulation.

<Undercoat layer coating solution>
・ 50 parts of mixed resin emulsion of polyester resin and urethane resin (WAC-15X: Takamatsu Yushi Co., Ltd., solid content 20%)
・ 50 parts of water

The ink jet recording materials obtained in Examples , Reference Examples and Comparative Examples were recorded with an ink jet printer (SOLJETSC-500: Roland) using a glycol-based ink (ECO-SOLLINK: Roland). Evaluation was performed. The results are shown in Table 1.

(1) Adhesiveness The ink jet recording materials of Examples , Reference Examples and Comparative Examples were printed with an ink amount of 300%. After leaving to dry for 24 hours, cuts were made in the printed portion of the inkjet recording material so that 100 squares with a gap interval of 1 mm were formed. Subsequently, the cellophane adhesive tape was affixed on the part where the cut was made, and the state of the coating film after peeling was visually observed. As a result, “◯” indicates that it was not peeled off at all, “Δ” indicates that the area of less than 50% was peeled off, and “x” indicates that the area of 50% or more was peeled off.

(2) Ink drying property A sheet of paper was stacked on the ink receiving layer side of the ink jet recording material after printing after a predetermined time, and it was observed whether or not the ink was transferred. As a result, “○” indicates that the ink amount of 200% is not transferred within 7.5 minutes after recording, and the ink amount is transferred within 7.5 minutes after the ink amount of 200% has elapsed after 7.5 minutes. The thing which did not carry out was made into "(triangle | delta)".

(3) Heat resistance The inkjet recording material was left in an environment of 60 ° C. for 1 week, and the presence or absence of discoloration was visually evaluated. As a result, “◯” indicates that no change was observed, and “X” indicates change in color.

The inkjet recording materials of Reference Examples 1 to 3 and Examples 4 to 5 all have an ink receiving layer containing a polyvinyl acetal resin, and vinyl alcohol, acrylic acid, hydroxy, and the like are interposed between the synthetic resin film and the ink receiving layer. It has an undercoat layer containing a copolymer composed of at least one selected from alkyl acrylate and vinyl chloride and vinyl acetate. Therefore, all of them were excellent in ink drying property and excellent in adhesion between the synthetic resin film and the ink receiving layer. In each of these, the undercoat layer was as thin as 2 μm, and the structure having an ink receiving layer on the undercoat layer was adopted. Therefore, the undercoat layer was not discolored by heat or oxygen.

  The ink jet recording material of Comparative Example 1 does not have an undercoat layer. Therefore, the adhesion between the synthetic resin film and the ink receiving layer was poor. Moreover, it was inferior to the ink drying property of the Example.

  The inkjet recording material of Comparative Example 2 uses the undercoat layer of Example 1 as an ink receiving layer. Therefore, although the adhesiveness between the synthetic resin film and the ink receiving layer is sufficient, the ink drying property is inferior to that of the example. Further, since the undercoat layer of the example was exposed to the surface with a thickness of 30 μm, discoloration occurred.

  The ink jet recording materials of Comparative Examples 3 to 5 have an undercoat layer made of a vinyl chloride-vinyl acetate copolymer, and the copolymer contains vinyl alcohol, acrylic acid, hydroxyalkyl as a copolymer component. It does not contain at least one selected from acrylates. Accordingly, the adhesion between the synthetic resin film and the ink receiving layer is not sufficient.

  The ink jet recording materials of Comparative Examples 6 to 9 have an undercoat layer, and the resin constituting the undercoat layer is at least one selected from vinyl alcohol, acrylic acid, and hydroxyalkyl acrylate, and vinyl chloride and acetic acid. It is not a copolymer made of vinyl. Accordingly, the adhesion between the synthetic resin film and the ink receiving layer is not sufficient. Moreover, it was inferior to the ink drying property of the Example.

Claims (2)

  An inkjet recording material having an ink receiving layer containing a polyvinyl acetal resin on a synthetic resin film, and at least one selected from acrylic acid and hydroxyalkyl acrylate and vinyl chloride between the synthetic resin film and the ink receiving layer And an undercoat layer comprising a copolymer of vinyl acetate. The composition of the copolymer is 58 to 98% by weight of vinyl chloride, 1 to 40% by weight of vinyl acetate, and 0.3 to 20% by weight of the total composition of acrylic acid and hydroxyalkyl acrylate. The ink jet recording material according to claim 1, wherein