JP4359549B2 - Ink-receiving paper manufacturing method - Google Patents

Description

  The present invention includes a base sheet, a foamed resin layer formed by foaming by heating a heating foaming agent contained in the thermoplastic resin layer, a foam surface adjustment resin layer mainly composed of a thermoplastic resin, The present invention relates to a method for producing ink image receiving paper including an ink image receiving layer for receiving ink.

  Ink-receiving paper such as ink-jet paper used for printing by an ink-jet printer is known. The ink image receiving paper is used as a wallpaper for surface decoration used in, for example, the exterior and interior of buildings, joinery, furniture, and interiors of passenger cars. Such wallpaper is manufactured by printing a desired pattern on inkjet paper for wallpaper by an inkjet printer. The manufactured wallpaper is used depending on the application. Some ink-receiving paper for wallpaper or the like is manufactured by foaming / embossing as a surface treatment to form a concavo-convex pattern on the surface.

  Conventionally, as this type of wallpaper, a so-called PVC wallpaper in which a vinyl chloride resin layer is formed on a paper substrate has been widely used. However, in recent years, vinyl chloride has a problem that dioxins are likely to be generated at the time of combustion and disposal, and therefore tends to be avoided. As an alternative to this, there is a wallpaper in which an aqueous emulsion is used and an aqueous emulsion coat layer is formed.

  Patent Document 1 discloses a decorative sheet including a foaming process that has been developed by the inventor of the applicant. This decorative sheet is manufactured by previously forming an unfoamed resin layer and a resin layer on a production line such as a factory, and then foaming after applying pattern printing to form a foamed resin layer. In the invention according to this application, since the printed pattern is affected by the foaming process, the influence can be suppressed, and a good pattern can be printed even when mass-produced on a production line.

  However, at the time of filing of Patent Document 1, ink jet printers were not popular, but ink jet printers were subsequently popularized. With the widespread use of this ink jet printer, there is a tendency for user needs to print a decorative sheet pattern more personally. Therefore, a new technical problem has arisen that an image is printed on the foamed resin layer of the decorative sheet by the ink jet printer in accordance with personal preference.

  As its technical problem, in the wallpaper having an aqueous emulsion coat layer formed, when an ink image receiving layer on which a pattern is printed by an ink jet printer is provided on a non-foamed aqueous emulsion coat layer and subjected to heat embossing, There is a case where there is no volume feeling and sharp embossing may not enter. Therefore, in order to prevent this point, the image printed on the water-based emulsion coat layer containing the unfoamed capsule foaming agent is heated and foamed to give embossed texture, and there is a sense of volume. A sharp emboss is formed. Such an ink receiving paper is reported in Patent Document 2 below.

  The ink image-receiving paper having a concavo-convex pattern formed on the surface described in Patent Document 2 contains a heating foaming agent in a thermoplastic resin on a backing substrate serving as a base material sheet, and the heating foaming agent is heated. A foamed resin layer formed by foaming is formed, and the ink-receiving layer is formed on the foamed resin layer, and an ink image-receiving layer that receives printing ink added from an inkjet printer during printing is formed.

Patent Document 2 discloses a method for manufacturing the ink image receiving paper. In the method for producing ink image-receiving paper described in Patent Document 2, it is disclosed that after the foamed resin layer is foamed, an uneven pattern by embossing is added or the ink image-receiving layer is formed.
JP-A-10-157045 Japanese Patent No. 3084275

  However, the ink receiving paper described in the above-mentioned Patent Document 2 may have a problem with proper printing. For example, the printed image may have a dark color tone and it may be difficult to form an image with a clear color tone.

  However, in recent years, it has been demanded by users of ink image receiving paper to improve printing suitability, and it is necessary to further improve printing suitability. The inventor diligently studied to improve the process for manufacturing ink-receiving paper that improves the quality of printing and the like further than the above application.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for producing ink image receiving paper that can improve quality such as printing suitability, adhesion, and bending characteristics.

  The base sheet of the present invention, a foamed resin layer formed by foaming by heating a heating foaming agent contained in the thermoplastic resin layer, a foam surface adjusting resin layer mainly composed of a thermoplastic resin, and an ink An ink image-receiving sheet comprising an ink image-receiving layer for receiving an image, an unfoamed resin layer forming step of forming an unfoamed resin layer before heating and foaming on the base sheet, and after forming the unfoamed resin layer, A foamed surface adjusting resin layer forming step for forming the foamed surface adjusting resin layer on the non-foamed resin layer, and after forming the foamed surface adjusting resin layer, heating the foaming resin in the unfoamed resin layer to heat the foamed resin. A foamed resin layer forming step of forming a layer; and an image receiving layer forming step of forming an ink image receiving layer for receiving ink on the foamed surface adjusting resin layer after the foamed resin layer is formed.

  It is preferable to include a concavo-convex pattern layer forming step of forming a concavo-convex pattern layer by forming a concavo-convex shape at least on the surface of the foam-adjusting surface adjustment resin layer after forming the foamed resin layer and before forming the ink image receiving layer. .

  It is preferable to include an embossing process for embossing at least the surface of the foamed surface adjusting resin layer after forming the foamed resin layer and before forming the ink image receiving layer.

  It is possible to provide a method for producing ink image receiving paper that can improve quality such as printing suitability, adhesion, and folding characteristics.

  EMBODIMENT OF THE INVENTION Below, the form for inventing is demonstrated based on drawing. In addition, about this embodiment, it is only one form for implementing this invention, and this invention is not limited by this embodiment. In the present embodiment, a method for producing an inkjet ink receiving paper for wallpaper, which has a pattern and an uneven pattern for decorating an inner wall surface of a building as an ink receiving paper and is used for printing by an inkjet printer, will be described with reference to the drawings. . In addition, in this drawing, it is a schematic cross-sectional explanatory view. For example, the foaming is originally large, and traces of foaming often appear on the surface of the ink image-receiving layer, but the illustration is omitted.

"Layer configuration and layer configuration method of ink receiving paper"
The wallpaper ink-jet ink image receiving paper 100 manufactured by the manufacturing method of the present embodiment whose sectional view is shown in FIG. 1 is obtained by heating and foaming the wallpaper ink-jet ink receiving paper 300 before heating and foaming shown in FIG. It is manufactured by embossing and forming the ink image receiving layer 16 on the surface of the ink jet ink receiving paper 200 for wallpaper before forming the ink image receiving layer on which the concave and convex pattern shown in the cross-sectional view of FIG. 2 is formed. . Each layer to be formed can be formed using a layer forming method common to those skilled in the art.

  The manufactured inkjet ink receiving paper 100 for wallpaper shown in FIG. 1 has a structure of backing member 10 / foamed thermoplastic resin layer 12 / foamed surface adjusting resin layer 14 / ink image receiving layer 16 and has a backing as a base material. The member 10, the foamed thermoplastic resin layer 12 that is heated and foamed to disperse the bubbles in the resin, the foam surface adjustment resin layer 14 mainly composed of the thermoplastic resin, and the ink image receiving layer 16 that receives the ink from the ink jet printer. And have.

  The ink-jet ink image-receiving paper 200 for wallpaper before forming the ink image-receiving layer shown in FIG. 2 has a structure of backing member 10 / foamed thermoplastic resin layer 12 / foamed surface adjusting resin layer 14, and the backing member 10 serving as a substrate. And a foamed thermoplastic resin layer 12 in which bubbles are dispersed in the resin by heating and foaming, and a foamed surface adjusting resin layer 14 mainly composed of a thermoplastic resin. An uneven shape added by embossing is formed on the surface of the thermoplastic resin layer 12, and these form an uneven pattern layer.

  The inkjet ink receiving paper 300 for wallpaper before heating and foaming shown in FIG. 3 has a structure of backing member 10 / unfoamed resin layer 22 / foamed surface adjusting resin layer 14, and the backing member 10 serving as a base material and resin It has an unfoamed resin layer 22 in which a heated foaming agent before foaming is dispersed, and a foam surface adjustment resin layer 14 mainly composed of a thermoplastic resin.

The backing member 10 has a support surface that supports the non-foamed resin layer 22 on the contact surface with the non-foamed resin layer 22, while the inner wall of the building is opposed to the contact surface with the non-foamed resin layer 22. It has the adhesion surface where the adhesive used for adhesion of is applied. The backing substrate 12 can be made of paper, woven fabric, nonwoven fabric, synthetic paper, titanium paper, glass nonwoven fabric, or the like. The paper is preferably flame retardant paper for wallpaper, aluminum hydroxide paper, inorganic paper, or general paper having a basis weight of 50 to 300 g / m ² , desirably 70 to 150 g / m ² . When using a water-soluble resin emulsion as the resin of the unfoamed resin layer 22 and considering expansion and contraction due to the influence of water at the time of emulsion coating, a coating layer that increases water resistance and reduces moisture permeability on at least the surface of the base sheet. It may be provided.

  The unfoamed resin layer 22 is a coating layer in which a thermoplastic resin, a plasticizer, a stabilizer, a foaming agent, a lubricant, an antioxidant, a filler, a surfactant, and the like are mixed. The unfoamed resin layer 22 does not actually need to contain all of the above-mentioned agents, and may have at least a thermoplastic resin and a foaming agent contained therein. The mixing ratio and the like of these mixtures are determined so that a sufficient foaming effect can be obtained under the conditions of temperature and time for heating and foaming. For example, the mixing ratio is determined so that a sufficient foaming state is obtained by heating for several tens of seconds to 2 minutes at a temperature of 180 ° C. to 230 ° C. The unfoamed resin layer 22 containing a mixture in an appropriate ratio according to these conditions is such that the coating film formed by drying the unfoamed resin layer 22 on the backing member 10 to a certain degree of thickness (for example, about 0.3 mm). ) To be applied.

The thermoplastic resin can contain a foaming agent, and a resin that can be formed on the backing member is selected. Aqueous emulsion resin, polyethylene resin, polyacrylic resin, polyvinyl acetate resin, polyurethane resin, polystyrene resin, polyvinyl chloride, synthetic resin rubber and the like can be used. Polyethylene resin is suitable because it has advantages such as less generation of dioxins when it is burned as waste and less harm to the environment. Most preferred is an aqueous emulsion resin. As the aqueous emulsion resin, various non-vinyl chloride emulsions can be used, but general ethylene-vinyl acetate, acrylic resin alone or blends, and copolymerization are preferable. The same resin can be used in common for the unfoamed resin layer, the foamed surface adjusting resin layer, and the raised printing layer. In addition to inorganic fillers, pigments, and capsule foaming agents (not included in the foam-adjusted resin layer), various antifoaming agents, thickeners, dispersants, drying retarders, flame retardants Add antiseptics, fungicides, etc. to paint. Various methods such as comma coating, doctor coating, and roll coating can be applied to the emulsion paint. After coating on the base material sheet, for example, drying is performed at 120 ° C. for about 1 minute with a hot air oven dryer to produce an unfoamed base coat raw material. The coating amount of the non-foamed resin layer in the aqueous emulsion is 50 to 250 g / m ² (when dried), and preferably 80 to 200 g / m ² (when dried).

  A filler that is suitable for obtaining texture and whiteness is selected. As the calcium carbonate and the filler, a flame retardant inorganic filler or a general inorganic filler such as calcium carbonate can be used. In particular, since wallpaper is used for the inner wall of a building, fire prevention performance is necessary, but emulsion resin is particularly suitable because it is flammable. Examples of the inorganic filler having a flame retardant effect include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, zinc borate, zinc oxide, magnesium oxide, inorganic spheres, organic hollow spheres, and barium metaborate. Examples of general inorganic fillers include calcium carbonate, barium sulfate, talc, carion, and clay. The unfoamed resin layer and the foamed surface adjusting resin layer are preferably added with about 50 to 200 parts of filler relative to the resin 100. Further, since smoothness is required for printing, the average particle size is preferably 10 μm or less, and preferably 5 μm or less.

  Plasticizers include phthalate ester, phosphate ester, chlorinated fatty acid ester, chlorinated paraffin, epoxy, polyester, and adipic ester plasticizers such as dioctyl phthalate, dibutyl phthalate, and butyl benzyl phthalate. Can be used.

  As the stabilizer, a stabilizer suitable for controlling the decomposition temperature of the foaming agent, that is, the foaming temperature is selected and selected. Composite stabilizers such as cadmium, barium, and zinc, lead stabilizers, tin stabilizers, calcium stabilizers, and the like can be used.

  The foaming agent may be a heating foaming agent that foams by heating, and either a pyrolytic foaming agent or a capsule foaming agent can be used. As a component of the foaming agent, nitropentamethylenetetramine, azodicarbonamide, toluenesulfonylhydrazine, azobisisobutylnitrile, benzenesulfonylhydrazine and the like can be used. The capsule foaming agent is a microsphere having a particle size of 10 to 30 μm in which a low boiling point solvent is encapsulated with a coating or shell of a thermoplastic polymer material. As the shell material, an acrylonitrile / vinylidene chloride copolymer, an acrylonitrile / acrylic copolymer, a nitrile copolymer, or the like is used. As the capsule foaming agent, a high-temperature foaming agent that can be heated at 140 (160) to 190 ° C. for 1 minute to obtain the maximum magnification, and the shell material is a nitrile copolymer and the inclusion gas is pentane is suitable. is there.

  A lubricant that is suitable for improving the processability of embossing is selected. Polyolefin type, stearic acid, stearic acid ester, stearyl alcohol, petrolatum, polyglycol ester of fatty acid and the like can be used.

  A surfactant is selected that is suitable for emulsifying a thermoplastic resin. Phosphoric acid monoester, phosphoric acid diester, polyoxyethylene sorbitan monooleate, polyoxyethylene lauryl ether, polyethylene glycol monolaurate and the like can be added.

For the foam surface adjustment resin layer 14, a general thermoplastic resin containing no foaming agent can be used. A water-soluble resin emulsion is preferable, and a water-soluble urethane emulsion is more preferable. When a water-soluble urethane emulsion is used together with the ink image receiving layer 16, the ink image receiving layer 16 and the foamed surface adjusting resin layer 14 are in close contact with each other, and the adhesiveness is improved. In order to increase the volume as a whole, it is preferable that the coating amount is small. However, if the coating amount is too small, the surface of the foamed resin layer is destroyed due to the influence of the surface exposure of bubbles during foaming. The coating amount is 1 to 20 g / m ² , preferably ² to 10 g / m ² . The method of coating the foam surface adjustment resin layer 14 is the same as that for the non-foam resin layer, but the non-foam resin layer and the foam surface adjustment resin layer are wet in addition to coating the non-foam resin layer after forming the dry film. It is also possible to dry after stacking two layers in the state.

  As the ink image receiving layer 16, an image receiving layer suitable for ink image reception can be selected. Examples of inks produced by inkjet printers include dye inks and pigment inks. For example, when pigment inks are used, they are in a porous state that absorbs the solvent of the pigment ink and keeps the pigment particles from falling off. It is preferable. The ink image-receiving layer 16 has a pore size of 1 to 30 μm, and the pore volume ratio is preferably 20 to 70%. Such a porous ink image-receiving layer 16 is formed by mixing resin (acrylic resin, polymethyl methacrylate resin, or copolymer resin of methyl methacrylate and amide resin, polyester, or a mixture of fine particles such as silica and alumina alone or mixed. It is made by applying and drying a liquid dispersed in a water-insoluble binder resin such as a resin. The ink image-receiving layer 16 can have an appropriate film thickness in this dry state, for example, 5 to 40 μm. Here, the film thickness can be determined by comparative consideration of the balance between the ease of ink image reception and the film thickness that can properly represent the concavo-convex pattern layer when embossing is performed. For example, when it is desired to highlight a concavo-convex pattern, it is possible to adopt a mode in which the thickness is a thin layer of about 5 to 25 μm. As the printing ink for forming the ink image-receiving layer 16, various printing inks can be used regardless of whether they are solvent-based or water-based. Examples of the main resin include non-vinyl chloride resins such as acrylic, urethane, polyester, cellulose, and casein. Various pigments can be used regardless of whether they are organic or inorganic. In addition, bright pigments such as aluminum, brass, vapor deposited powder, and pearl pigment (each color such as white and gold) are easily provided with effects on the foamed surface adjusting resin layer 14. As a printing method, various printing methods such as comma coat, gravure, offset, flexo, and silk can be applied. The ink image receiving layer 16 may be provided with a transparent coating layer on its surface for gloss adjustment, and various paints can be used regardless of whether they are solvent-based or water-based. Examples of matting agents include silica, alumina, calcium carbonate and the like. The concavo-convex pattern layer is usually formed also on the surfaces of the foamed surface adjustment resin layer 14 and the foamed resin layer 12, but the concavo-convex pattern layer is also formed only at least on the foamed surface adjustment resin layer 14 in this embodiment. Can be implemented.

"Foam manufacturing process"
A process of manufacturing the inkjet image receiving paper 100 for wallpaper through the inkjet image receiving paper 200 before forming the image receiving layer using the inkjet image receiving paper 300 before heating and foaming will be described.

  In the inkjet image receiving paper 300 before heating and foaming shown in FIG. 1, the unfoamed resin layer 22 is first heated by the heating process, and the heating foaming process in which the heated foaming agent in the unfoamed resin layer 22 is foamed by heating. The foamed thermoplastic resin layer 12 is formed. After the heating and foaming step, the surface of the foamed thermoplastic resin layer 12 is embossed to form a concavo-convex pattern, and the inkjet image receiving paper 200 for wallpaper before the ink image receiving layer 16 is formed is manufactured. In addition, in the manufacturing process including the concavo-convex pattern layer forming step such as embossing, the concavo-convex pattern layer forming step is not an indispensable step, and the present embodiment can be implemented even if omitted. is there. It is preferable to perform embossing, for example, when a capsule foaming agent is used, large bubbles may be generated due to sudden foaming in the foaming process, and it is difficult to ensure the uniformity of the bubbles. Such as the case. The concept of embossing in this case is not limited to shaping irregularities, but also includes the concept of pressing with a relatively flat roll or a roll engraved with satin.

  What is necessary is just to use the apparatus etc. which can heat-foam the heating foaming agent in the unfoamed resin layer 22 for a heating foaming process. For example, a heating oven can be used. Inkjet image-receiving paper 200 before being heated and foamed is introduced into the heating oven and heated internally, and then continuously heated at a temperature of 180 ° C. to 230 ° C. for several tens of seconds to 2 minutes. The resin layer 22 is heated and foamed. By this heating, the unfoamed thermoplastic resin layer 22 becomes the foamed resin layer 12 having a thickness of about 3 to 5 times.

  The embossing can use a general process that can add an uneven pattern to the surface. For example, a heated embossing roller or embossing plate can be heated and pressed from the ink image receiving layer 16 side to add a concavo-convex shape to the surface to form a concavo-convex pattern layer. That is, in the embossing process, it is easy to match a large number of holes dispersed in the foamed resin layer 12 below the foamed surface adjusting resin layer 14 generated by heat foaming with the unevenness of the embossing roller or the embossing plate. The ink-jet image-receiving paper 200 for wallpaper before forming the ink image-receiving layer in which the uneven pattern is faithfully transferred is manufactured. If an uneven pattern can be formed, embossing is not necessary.

The ink-jet image receiving layer 16 is formed on the surface of the ink-jet image receiving paper for wallpaper 200 before the ink image-receiving layer is formed, and the ink-jet image receiving paper for wallpaper 100 is manufactured. A pigment ink is jetted onto the surface of the ink image receiving layer 16 of the ink jet image receiving paper 100 for wallpaper using an ink jet printer in a pattern that becomes a wallpaper pattern, and the ejected pigment ink is taken into the ink image receiving layer 16 to be a required pattern. Form.

  By using the ink-jet image receiving paper 100 of the present embodiment, it is possible to improve printing suitability, adhesion, and bendability.

  The order of the conventional ink image-receiving layer formation and the heating and foaming process is changed back and forth, and the ink image-receiving paper is produced by forming the ink image-receiving layer before the heating and foaming process. About the manufacturing method, the printing appropriateness test by the inkjet printer was done. As a result, in the manufacturing method in which the ink image-receiving layer was formed before the heating and foaming step, it was found that the printing suitability was insufficient, the color tone constituting the image was dark, and it was difficult to form an image with a clear color tone did.

  The reason for this will be considered from the following examples as an example. In order to ensure printing suitability, the ink image-receiving layer is required to have a certain degree of surface smoothness during printing. However, if the ink image-receiving layer is applied before foaming, the surface of the ink image-receiving layer becomes rough due to the foaming, and thus the smoothness necessary for ink image reception may not be ensured. Therefore, the component constituting the ink image-receiving layer is originally formed by forming the foam surface adjustment layer on the foamed resin layer in advance, and after applying foaming, foaming with a certain degree of smoothness is applied, and then the ink image-receiving layer is further applied. In addition to the image receiving ability, it also provides moderate surface smoothness. Thereby, it is considered that the printability is further improved.

  Furthermore, the case where a foam surface adjustment layer was applied after foaming to form an ink image receiving layer (for example, Comparative Example 3 in the following Examples) was also compared by an adhesion test. As a result, it was found that in addition to insufficient printability, it was difficult to obtain adhesion and was easily peeled off. It is considered that this is because the ink image-receiving layer is formed after foaming (embossing), and is caused by cohesive failure due to weakening in the foamed resin layer by the foaming process. Further, when the foaming surface adjustment layer is not provided between the foamed resin layer and the ink image-receiving layer (for example, Comparative Example 2 in the following examples), cohesive failure or ink accompanying weakening in the foamed resin layer due to the foaming process. It is considered that peeling of the image receiving layer occurs.

  Based on the above, the appropriateness of printing, adhesion, and folding characteristics of the wallpaper ink-jet image receiving paper (foamed embossed type) manufactured according to this embodiment (example) and the conventional ink-jet image receiving paper for wallpaper (comparative example) Evaluation was performed. The results are shown in Table 1.

"Production method"
"Example 1"
A foamed surface adjusting resin layer was formed by dry-coating 1 to 10 g of the following composition A by comma coating or roll coating on an original fabric coated with EVA (ethylene-vinyl acetate copolymer) on the backing paper.

  <Composition A> 100% polyurethane resin. A coating solution in the form of an aqueous emulsion (solid content 10 to 20%, water 80 to 90%) at the time of coating.

After providing this foaming surface adjusting resin layer, it was heated and foamed at 170 ° C. for 1 minute in a foaming furnace, and then embossed with an infrared heater at a surface temperature of 170 to 200 ° C. Thereafter, an ink image-receiving layer was formed thereon with a composition B of the following composition B at 20 g / m ² using a comma coat.

<Composition B>
100 parts by weight of polyurethane resin, 50 parts by weight of micro silica When coating, a coating solution in the form of an aqueous emulsion (solid content 15-30%, water 70-80%).

"Example 2"
Example 2 differs from Example 1 only in the method of forming an ink image-receiving layer with the composition B after embossing. In Example 2, after embossing, an ink image-receiving layer was formed on the composition B with a comma coat at 30 g / m ² on the embossing.

"Comparative Example 1"
An ink image-receiving layer was formed by dry-coating 5 to 25 g of 100% rubber-based resin with a comma coat or roll coat on an original fabric coated with EVA (ethylene-vinyl acetate copolymer) on the backing paper.

  After the ink image-receiving layer was provided, it was heated and foamed with heat corresponding to 170 ° C. for 1 minute in a foaming furnace, and then embossed with an infrared heater at a surface temperature of 170 to 200 ° C. for production.

"Comparative Example 2"
An original fabric coated with EVA (ethylene-vinyl acetate copolymer) on the backing paper is heated and foamed at 170 ° C. for 1 minute in a foaming furnace, and then the surface temperature is set at 170 to 200 with an infrared heater. Embossing was performed at a temperature of ° C.

After the embossing, an ink image-receiving layer was formed on the composition B with a comma coat at 30 g / m ² thereon.

“Comparative Example 3”
An original fabric coated with EVA (ethylene-vinyl acetate copolymer) on the backing paper is heated and foamed at 170 ° C. for 1 minute in a foaming furnace, and then the surface temperature is set at 170 to 200 with an infrared heater. Embossing was performed at a temperature of ° C. After embossing, 1-10 g of the composition A was dry-coated by comma coating or roll coating to form a foamed surface adjusting resin layer.

After forming the foamed surface adjusting resin layer, the composition B was manufactured by forming an ink image-receiving layer with a comma coat at 30 g / m ² .

"Evaluation methods"
・ As for proper printing, Epson's MC-9000, Roland DG's "FJ500", and Hewlett Packard's "DJ5000PS UV" are used for printing and evaluated for image clarity and ink bleeding. Went.

  The evaluation criteria for proper printing are as follows.

◎: Image sharpness and ink bleeding are very good ○: Image sharpness and ink bleeding are good △: Image sharpness and ink bleeding are defective ×: Image There are defects in both sharpness and ink bleeding

  ・ For adhesion, attach cellotape (registered trademark) (manufactured by Nichiban Co., Ltd.) so that air does not enter, and rub it back and forth with a squeegee 10 times to make it adhere to the printed image receiving layer surface, and from the printed image receiving layer surface The film was peeled off quickly at an angle of 45 degrees, and the evaluation was made based on whether or not peeling occurred due to cohesive failure of the foamed resin layer or the ink image-receiving layer.

  The evaluation criteria for adhesion are as follows.

○: Little or no △: Peeling occurs partly ×: Peeling occurs entirely

  -The bending characteristics were evaluated by bending the printed image-receiving layer surface side to a mountain side and bending it at 180 ° or 90 °.

  The evaluation criteria for the bending characteristics are as follows.

◎: Cracks in the printed part (white area of the background) are hardly noticeable ○: Cracks in the printed part (white area of the background) are inconspicuous △: Cracks in the printed part (white area of the background) are conspicuous X: Cracks in the printed part (white area of the ground) are noticeable

"Results and Discussion"
"Example 1" and "Example 2"
Sufficient printability, adhesion and folding characteristics were obtained.

"Comparative Example 1"
Adequate printing, adhesion, and folding characteristics were not obtained. One of the factors that did not achieve adequate printing was that the foam-controlling resin layer did not provide the foaming control effect during foaming, and the uneven shape formed after the foaming / embossing process was ink-printed. This is considered to be because the surface was exposed and the surface smoothness required at the time of ink printing was not sufficient. One reason that sufficient adhesion and folding characteristics could not be obtained is considered to be because the binder effect for further bonding the ink image receiving layer and the foamed resin layer due to the presence of the foamed surface adjusting resin layer could not be obtained.

"Comparative Example 2"
Insufficient printability was obtained, resulting in poor adhesion and folding characteristics. One factor that the printing suitability was not sufficiently obtained is considered to be that the foaming control effect at the time of foaming by the foam surface adjustment resin layer was not obtained. One reason for the poor adhesion and folding characteristics is that the presence of the foam-adjusting resin layer did not provide an adhesive effect that further adheres the ink image-receiving layer to the foamed resin layer. This is probably because the thickening / joining effect by the embossing process could not be obtained due to being in the latter stage of the process.

“Comparative Example 3”
Adequate printing and adhesion were not obtained sufficiently, and the bending characteristics were not good. One factor that the printing suitability was not sufficiently obtained is considered to be that the foaming control effect at the time of foaming by the foam surface adjustment resin layer was not obtained. One of the factors that did not provide adequate printing and adhesion was that the foaming surface adjusting resin layer forming process and the image receiving layer forming process were in the latter stage of the embossing process, so that the thickening / bonding effect by the embossing process could not be obtained. it is conceivable that.

"Evaluation"
In this example, the foaming control effect at the time of foam formation by the foam surface adjustment resin layer formed before foaming was controlled so as to produce fine foaming, and the uneven pattern by embossing was made uniform and formed. It will be considered that an ink image-receiving paper with good printability can be obtained by forming the image-receiving layer on the concavo-convex shape and smoothing the surface.

  Further, in this embodiment, the thickening effect by embossing is obtained for the foamed surface adjusting resin layer, and the image receiving layer is bonded by the adhesive action by the foamed surface adjusting resin layer, so that the adhesion and folding characteristics are improved. And consider. In addition, the foam adjustment layer can generate fine bubbles, the weakness of the inner surface of the foamed resin layer is reduced, and the cohesive failure is less likely to occur in the evaluation method by peeling with the cellophane tape. Consider that the bending characteristics have been improved.

It is sectional drawing of the manufactured inkjet ink image-receiving paper for wallpaper. It is sectional drawing of the inkjet ink receiving paper for wallpaper before ink image receiving layer formation. It is sectional drawing of the inkjet ink image-receiving paper for wallpaper before foaming formation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Base material sheet 12 Foamed resin layer 14 Foamed surface adjustment resin layer 16 Ink image receiving layer 22 Unfoamed resin layer 100, 200, 300 Ink image receiving paper

Claims (3)

A base sheet, a foamed resin layer formed by foaming by heating a heating foaming agent contained in the thermoplastic resin layer, a foam surface adjustment resin layer mainly composed of a thermoplastic resin, and an ink image. A method for producing an ink image-receiving paper comprising an ink image-receiving layer,
An unfoamed resin layer forming step of forming an unfoamed resin layer before heating and foaming on the base sheet;
A foamed surface adjusting resin layer forming step of forming the foamed surface adjusting resin layer on the unfoamed resin layer after forming the unfoamed resin layer;
A foamed resin layer forming step of forming a foamed resin layer by heating the heating foaming agent in the unfoamed resin layer after the foamed surface adjustment resin layer is formed,
An ink receiving layer forming step of forming an ink receiving layer for receiving ink on the foam surface adjusting resin layer after forming the foamed resin layer. It is a manufacturing method of the ink image-receiving paper according to claim 1,
An ink receiving paper including a concavo-convex pattern layer forming step of forming a concavo-convex pattern layer by forming a concavo-convex shape at least on the surface of the foam adjustment resin layer after forming the foamed resin layer and before forming the ink image-receiving layer. Production method. It is a manufacturing method of the ink image-receiving paper according to claim 1,
A method for producing an ink image-receiving paper, comprising an embossing step of embossing at least the surface of the foam-adjusting resin layer after forming the foamed resin layer and before forming the ink image-receiving layer.

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