JP2997290B2 - Recording material for UV ink - Google Patents

Description

The present invention relates to a recording material for UV ink.

(Prior art) In recent years, UV-curable ink (hereinafter referred to as UV ink)
Has been developed and used for various printings. UV ink is
Since it can be rapidly cured by applying ultraviolet rays, it is possible to print on a substrate whose temperature cannot be increased during drying, and to have a feature that the printing speed can be increased.

(Problems to be solved by the invention) However, depending on the type of the base material, the UV ink
Adhesive strength may be very low. This tendency is particularly remarkable in a substrate having high smoothness.

The object of the present invention is, when printing with UV ink,
An object of the present invention is to provide a recording material having high adhesive strength.

(Means for Solving the Problems) The present invention provides a recording material for UV ink in which an alumina hydrate layer is provided on a base material.

In the present invention, a layer made of alumina hydrate is provided on the substrate. Therefore, a high adhesive strength can be obtained even for UV ink.

As the alumina hydrate, pseudo-boehmite is preferable because the adhesive strength of the ink is increased. Here, pseudo-boehmite is an aggregate of colloidal boehmite crystals (A10 (OH)). The alumina hydrate layer has a pore structure substantially composed of only pores having a radius of 10 to 100 mm and a pore volume of
When it is 0.3 to 1.0 cc / g, it is preferable because it has sufficient absorbency and at the same time, the alumina hydrate layer has transparency. At this time, if the substrate is transparent, the obtained recording material is also transparent. Even when the substrate is opaque, it is possible to improve the adhesive strength of the ink without impairing the texture of the substrate.

Desirably, in addition to these physical properties, the average pore radius of the ink receiving layer is 15 to 30 ° and ± 10 ° of the average pore radius.
When the volume of pores having a radius in the range of 55% or more of the total pore volume is particularly preferred from the viewpoint of compatibility between absorbency and transparency. Even if the average pore radius of the ink receiving layer is 30 to 50 °, the transparency is slightly lower than the former, but a recording material having both absorptivity and transparency can be obtained. In this case, the volume of pores having a radius in the range of ± 10 ° of the average pore radius is the total pore volume.
Preferably it is at least 45%. The measurement of the pore radius in the present invention is based on the nitrogen desorption method.

In the present invention, various substrates can be used. The substrate of the present invention may be one that does not substantially absorb ink, for example, polyethylene terephthalate, polyester, polycarbonate, plastics such as fluororesins, or glass, metal, ceramics, and the like can be used. . The form of the substrate is not particularly limited, and a film shape, a sheet shape, or various molded products are appropriately used. Further, for the purpose of improving the adhesive strength of the alumina hydrate layer, a corona discharge treatment, an undercoat, or the like can be performed.

The thickness of the alumina hydrate layer is appropriately selected depending on the type and amount of the ink used for printing, but it is generally preferable to employ about 1 to 20 μm. If the thickness of the alumina hydrate layer is less than 1 μm, the ink adhesion strength may not be sufficiently obtained, and if the thickness of the alumina hydrate layer exceeds 20 μm, the strength of the alumina hydrate layer may be insufficient. , And the transparency may also be impaired.

The means for providing an alumina hydrate layer on a substrate is a slurry obtained by adding a binder to alumina hydrate, and is applied using a roll coater, an air knife coater, a blade coater, a rod coater, a bar coater, etc., and dried. A method can be adopted. As the alumina hydrate, it is preferable to use an alumina sol because a smooth layer can be easily obtained. As the alumina sol, sol-like boehmite is preferable. Binders include starch and its modified products, polyvinyl alcohol and its modified products, SBR
Latex, NBR latex, hydroxycellulose,
Organic substances such as polyvinylpyrrolidone can be used. If the amount of the binder used is too small, the strength of the alumina hydrate layer becomes insufficient, and if it is too large, the adhesive strength of the ink may be reduced.
It is preferable to employ about 50% by weight.

In the recording material of the present invention, various types of UV inks can be used without particular limitation. For example,
Polyester acrylate, epoxy acrylate, and the like may be used as a resin component of the ink.

(Example) Example 1 Boehmite sol (catalyst AS-2, manufactured by Catalyst Kasei Co., Ltd.)
One part by weight (solid content) of polyvinyl alcohol was added to 5 parts by weight (solid content), and water was further added to prepare a coating solution having a solid content of about 10%. This coating liquid is applied onto a sheet-like substrate made of polyethylene terephthalate (thickness: 100 μm) subjected to corona discharge treatment using a bar coater so that the film thickness when dried becomes 5 μm, and dried. A recording material provided with an alumina hydrate layer made of pseudo-boehmite was obtained.

The average pore radius of the obtained alumina hydrate layer is 20 mm,
The pore volume with a pore radius of 10 to 30 ° was 60% of the entire pore volume.

Example 2 A recording material was obtained in the same manner as in Example 1, except that the substrate was changed from polyethylene terephthalate to a tetrafluoroethylene-ethylene copolymer. The pore size distribution of the obtained alumina hydrate layer was the same as in Example 1.

Example 3 A recording material was obtained in the same manner as in Example 1 except that the substrate was changed from polyethylene terephthalate to polycarbonate. The pore size distribution of the obtained alumina hydrate layer was the same as in Example 1.

Examples 4 to 6 Recording materials were obtained in the same manner as in Examples 1 to 3, except that the boehmite sol in Examples 1 to 3 was changed to Cataroid AS-3 (manufactured by Catalyst Kasei Co., Ltd.). Here, Examples 4, 5, and 6 correspond to Examples 1, 2, and 3, respectively.

The obtained alumina hydrate layer had an average pore radius of 40 ° in all of Examples 4 to 6, and the pore volume of the pore radius of 30 to 50 ° was 60% of the entire pore volume.

The above recording material was printed using a UV ink for polyester and a UV ink for polycarbonate using a screen printing machine. The results of testing and evaluating the adhesive strength by a grid test specified in JIS K5400 are shown in the table. In the table, ○ indicates that peeling did not occur due to cuts. Δ indicates that slight peeling due to cuts did not occur. × represents a particularly severe peeling.

The results of measuring the haze of each recording material are also shown in the table.

Comparative Examples 1 to 3 The same evaluation test was performed on the substrate itself used in the examples. The results are shown in the table. Note that Comparative Examples 1, 2, and 3 correspond to the base materials of Examples 1, 2, and 3, respectively.

(Effect of the Invention) By using the recording material of the present invention, printing with a UV ink on a base material can be favorably performed. When a transparent base material is used in the recording material of the present invention, a transparent recording material with less haze can be obtained.

Claims (3)

(57) [Claims] 1. A recording material for UV ink comprising an alumina hydrate layer provided on a substrate. 2. The recording material for a UV ink according to claim 1, wherein the alumina hydrate is pseudo-boehmite. 3. The recording material for UV ink according to claim 1, wherein the alumina hydrate is obtained by applying and drying an alumina sol.