Sheet

Abstract

The present invention provides a sheet, wherein the sheet has an excellent low-gloss feeling; even when oblique light is incident on a surface of the sheet, diffuse reflection of the light is suppressed, the surface is less likely to look white when viewed obliquely, and a design represented on the sheet can be visually recognized; and the sheet has excellent designability. In the sheet, a surface of the sheet has an arithmetic average roughness Ra (JIS B0633: 2001) of 0.7 m or less, and the reflectance at a detection angle equal to a regular reflection angle 5, measured by a variable angle photometer when the surface is irradiated with incident light at an incident angle of 75, is 50% or less of the reflectance at the regular reflection angle.

Claims

1. A sheet, wherein a surface of the sheet has an arithmetic average roughness Ra (JIS B0633: 2001) of 0.7 m or less, and the reflectance at a detection angle equal to a regular reflection angle 5, measured by a variable angle photometer when the surface is irradiated with incident light at an incident angle of 75, is 50% or less of the reflectance at the regular reflection angle, wherein the sheet has a surface-protecting layer comprising an ionizing radiation-curable resin on an uppermost surface, wherein the surface-protecting layer comprises silica fine particles and resin beads.

2. A sheet, wherein a surface of the sheet has an arithmetic average roughness Ra (JIS B0633: 2001) of 0.7 m or less, and the reflectance at a detection angle equal to a regular reflection angle 5, measured by a variable angle photometer when the surface is irradiated with incident light at an incident angle of 75, is 50% or less of the reflectance at the regular reflection angle, wherein the sheet has a picture pattern layer and a transparent resin layer comprising a polyolefin resin, wherein at least the picture pattern layer, the transparent resin layer, and the surface-protecting layer are laminated in this order on a base material sheet.

3. A sheet, wherein a surface of the sheet has an arithmetic average roughness Ra (JIS B0633: 2001) of 0.7 m or less, and the reflectance at a detection angle equal to a regular reflection angle 5, measured by a variable angle photometer when the surface is irradiated with incident light at an incident angle of 75, is 50% or less of the reflectance at the regular reflection angle, wherein the sheet is a decorative sheet.

4. The sheet according to claim 3, wherein the sheet is a decorative sheet for floor materials.

5. The sheet according to claim 1, wherein the ionizing radiation-curable resin is at least one member selected from the group consisting of acrylate resins, polyester resins, and epoxy resins.

6. The sheet according to claim 2, wherein the sheet has a transparent resin layer comprising a polyolefin resin.

7. The sheet according to claim 1, wherein the sheet has a transparent resin layer comprising a polyolefin resin.

8. The sheet according to claim 3, wherein the sheet has a picture pattern layer.

9. The sheet according to claim 1, wherein the sheet has a picture pattern layer.

10. The sheet according to claim 2, wherein the sheet has a thickness of 50 to 600 m.

11. The sheet according to claim 1, wherein the sheet has a thickness of 50 to 600 m.

12. The sheet according to claim 2, wherein the sheet is a decorative sheet.

13. The sheet according to claim 1, wherein the sheet is a decorative sheet.

14. The sheet according to claim 1, wherein the sheet is a decorative sheet for floor materials.

15. The sheet according to claim 2, wherein the ionizing radiation-curable resin is at least one member selected from the group consisting of acrylate resins, polyester resins, and epoxy resins.

16. The sheet according to claim 3, wherein the sheet has a thickness of 50 to 600 m.

17. The sheet according to claim 2, wherein the sheet has a surface-protecting layer comprising an ionizing radiation-curable resin on an uppermost surface, wherein the surface-protecting layer comprises silica fine particles and resin beads.

18. The sheet according to claim 3, wherein the sheet has a surface-protecting layer comprising an ionizing radiation-curable resin on an uppermost surface, wherein the surface-protecting layer comprises silica fine particles and resin beads.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a cross-sectional view showing an example of the sheet of the present invention.

(2) FIG. 2 is a cross-sectional view showing an example of the sheet of the present invention.

(3) FIG. 3 is a cross-sectional view showing an example of the sheet of the present invention.

(4) FIG. 4 is a cross-sectional view showing an example of the sheet of the present invention.

DESCRIPTION OF EMBODIMENTS

(5) The present invention is explained in detail below with reference to Examples and a Comparative Example. However, the present invention is not limited to these Examples.

Example 1

(6) A 60-m-thick polypropylene film, to which a corona discharge treatment was performed on both surfaces thereof, was prepared as a base material sheet. The back surface of the polypropylene film was coated with a two-component curable urethane resin, thereby forming a 2-m-thick back-surface primer layer.

(7) A 2-m-thick picture pattern layer was formed by gravure printing on the front surface of the polypropylene film using printing ink comprising a two-component curable acryl urethane resin.

(8) The picture pattern layer was coated with a two-component curable urethane resin adhesive to a solids content of 3 g/m.sup.2, thereby forming a 3-m-thick adhesive layer. A polypropylene-based resin was thermally melted and extruded on the adhesive layer using a T-die extruder, thereby forming an 80-m-thick transparent resin layer.

(9) Subsequently, the surface was subjected to a corona discharge treatment, and then coated with a two-component curable urethane resin to a solids content of 1 g/m.sup.2, thereby forming a primer layer (surface-protecting layer-forming primer layer; thickness: 2 m).

(10) The front surface of the primer layer was coated with a resin composition of a urethane acrylate-based electron beam-curable resin (EB resin) comprising 15 parts by mass of silica fine particles having an average particle size of 3 m based on 100 parts by mass of the resin solids content by a roll coating method so that the solids content of the resin composition was 15 g/m.sup.2, and so that the thickness (layer thickness) after curing was 15 m. Then, the electron beam-curable resin was cured by irradiation with an electron beam using an electron beam irradiation device in an environment with an oxygen concentration of 200 ppm or less at an acceleration voltage of 125 KeV with a dose of 5 Mrad, thereby forming a surface-protecting layer. Thus, a decorative sheet (total thickness: 164 m) was produced.

Example 2

(11) A sheet of Example 2 was produced in the same manner as in Example 1, except that the surface-protecting layer further contained, in addition to the silica fine particles, 5 parts by mass of acrylic beads having a particle size of 3 m based on 100 parts by mass of the resin solids content.

Example 3

(12) A sheet of Example 3 was produced in the same manner as in Example 1, except that the surface-protecting layer contained, as extender pigments, 10 parts by mass of fine particles A having a particle size equal to or less than the thickness of the surface-protecting layer (average particle size: 3 m) based on 100 parts by mass of the resin solids content, and 10 parts by mass of fine particles B having a particle size greater than the thickness of the surface-protecting layer (average particle size: 16 m) based on 100 parts by mass of the resin solids content.

Example 4

(13) Preparation of Gloss-Adjusting Layer-Forming Ink

(14) Gloss-adjusting layer-forming ink was prepared by mixing 7.5 parts by mass of ocher (iron oxide) as a coloring pigment and 7 parts by mass of silica particles having an average particle size of 4 m with 100 parts by mass (6.0 parts by mass as the resin content) of coloring ink comprising a polyvinyl butyral resin as a vehicle.

(15) The gloss-adjusting layer-forming ink was applied to the entire front surface of a primer layer by a gravure printing method to form a gloss-adjusting layer. A surface-protecting layer was formed on the front surface of the gloss-adjusting layer in the same manner as in Example 1, except that the thickness, the average particle size of silica, the Ra of the surface, and the reflectance ratio were changed as shown in Table 2. A sheet of Example 4 was produced in the same manner as in Example 1 except for the above.

Example 5

(16) Gloss-adjusting layer-forming ink prepared in the same manner as in Example 4 was applied to the front surface of a primer layer by a gravure printing method in a vessel picture pattern shape to form a gloss-adjusting layer. A surface-protecting layer was formed on the entire surface of the gloss-adjusting layer in the same manner as in Example 1, except that the thickness, the average particle size of silica, the Ra of the surface, and the reflectance ratio were changed as shown in Table 2. A sheet of Example 5 was produced in the same manner as in Example 1 except for the above.

Comparative Example 1

(17) A sheet of Comparative Example 1 was produced in the same manner as in Example 1, except that silica fine particles having an average particle size of 10 m were used in the surface-protecting layer, and the irregular shape formed on the surface of the sheet by the silica fine particles, which contributed to designability and imparted texture, was changed as shown in Table 1.

(18) The sheets of Examples 1 to 5 and Comparative Example 1 were evaluated by the following evaluation methods.

(19) Evaluation Method

(20) Ra (Arithmetic Average Roughness)

(21) Ra was measured by a measurement method according to JIS B0633: 2001. The measurement was performed using SURFCOM FLEX-50A (produced by Tokyo Seimitsu Co. Ltd.).

(22) Ratio of the Reflectance at a Regular Reflection Angle 5 to the Reflectance at the Regular Reflection Angle

(23) The reflectance at a regular reflection angle and the reflectance at the regular reflection angle 5 when incident light was incident at an incident angle of 75 were measured using a variable angle photometer (trade name: GC5000L, produced by Nippon Denshoku Industries Co., Ltd.). In this measurement method, the incident angle and the regular reflection angle refer, respectively, to the angles of incident light and reflected light relative to the normal line of the surface of the sheet. Using the measured reflectance at the regular reflection angle and reflectance at the regular reflection angle 5, the ratio of the reflectance at the regular reflection angle 5 to the reflectance at the regular reflection angle was calculated by the following formula:
[Ratio of reflectance at regular reflection angle 5 to reflectance at regular reflection angle (%)]=[(reflectance at regular reflection angle 5 (%))/(reflectance at regular reflection angle (%))]100
Evaluation of Visibility of Picture Pattern

(24) The visibility of the picture pattern of each sheet was evaluated. Specifically, the state of the surface of each decorative sheet was visually observed at an angle of 60 or more (oblique light) and an angle of 0 (front) relative to the normal line of the sheet surface. The observation results were evaluated according to the following evaluation criteria.

(25) A+: No white shining in oblique light observation, and no cloudiness in front observation.

(26) A: No white shining in oblique light observation, but slight cloudiness in front observation.

(27) C: White shining in oblique light observation, and no visual recognition of picture pattern.

(28) Designability

(29) The appearance of each sheet was observed by 20 subjects (adult men and women), and whether a wooden texture was expressed was evaluated according to the following evaluation criteria.

(30) A+: 90% or more of the subjects determined that a wooden texture was expressed.

(31) A: 70% or more and less than 90% of the subjects determined that a wooden texture was expressed.

(32) B: 50% or more and less than 70% of the subjects determined that a wooden texture was expressed.

(33) C: Less than 50% of the subjects determined that a wooden texture was expressed.

(34) Scratch Resistance (Micro-Scratch Test)

(35) Gloss Test (A Test)

(36) The sheets prepared in the Examples and the Comparative Example were each attached to a friction table part of a Martindale abrasion tester (Martindale 1300 series, model 1302 (model number), produced by James Heal), and the surface of the sheet was polished with Scotch-Brite Fleece SB7447 (produced by Sumitomo 3M Limited). Specifically, a test was conducted by polishing the surface of the sheet with the round Scotch-Brite (diameter: 9 cm) at a load of 6 N (load: 9 g/cm.sup.2) at a rotational frequency of 80 (5 Lissajous orbits). The 60 gloss values before and after the test were measured, and the rate of change in the gloss value was calculated based on the following formula:
(Rate of change in gloss value) (%)={[(gloss value before test)(gloss value after test)]/(gloss value before test)}100

(37) The calculated rate of change was evaluated according to the following evaluation criteria.

(38) A+: The rate of change in the gloss value is less than 15%.

(39) A: The rate of change in the gloss value is 15% or more and less than 20%.

(40) B: The rate of change in the gloss value is 20% or more and less than 30%.

(41) C: The rate of change in the gloss value is 30% or more.

(42) Scratch Test (B Test)

(43) The sheets prepared in the Examples and the Comparative Example were each attached to a friction table part of a Martindale abrasion tester (Martindale 1300 series, model 1302 (model number), produced by James Heal), and the surface of the sheet was polished with Scotch-Brite Fleece SB7440 (produced by Sumitomo 3M Limited). Specifically, a test was conducted by polishing the surface of the sheet with the round Scotch-Brite (diameter: 9 cm) at a load of 4 N (load: 6 g/cm.sup.2) at a rotational frequency of 160 (10 Lissajous orbits). Scratches on the surface of the sheet after the test were visually observed and evaluated according to the following evaluation criteria.

(44) A+: No scratches are found on the surface of the sheet.

(45) A: A few scratches are found on the surface of the sheet.

(46) B: Many scratches are found on the surface of the sheet.

(47) C: A great number of scratches are found on the surface of the sheet.

(48) The following Tables 1 and 2 show the results.

(49) TABLE-US-00001 TABLE 1 Comparative Example 1 Example 2 Example 1 Surface- Thickness (m) 15 15 15 protecting layer Extender pigment Silica Silica Silica Average particle 3 3 10 size of extender pigment (m) Resin beads None Added None Ra of sheet surface (m) 0.7 0.7 0.9 Ratio of reflectance at regular 50 50 70 reflection angle 5 to reflectance at regular reflection angle (%) Visibility of design A A+ C

(50) TABLE-US-00002 TABLE 2 Example 1 Example 3 Example 4 Example 5 Surface-protecting Thickness (m) 15 15 15 15 layer Fine particles A Silica Silica Silica Silica (extender pigment) Average particle size of 3 3 3 3 fine particles A (m) Fine particles B Silica (extender pigment) Average particle size of 16 fine particles B (m) Resin beads None None None None Gloss-adjusting layer None None Formed Formed Coating method of gloss-adjusting layer Entire Pattern surface shape Ra of sheet surface (m) 0.7 0.7 0.5 0.6 Ratio of reflectance at regular reflection angle 50 50 45 45 5 to reflectance at regular reflection angle (%) Visibility of design A A A+ A+ Designability A A A A+ Scratch resistance Gloss test (A test) A A+ A A (micro-scratch test) Scratch test (B test) A A+ A A

REFERENCE SIGNS LIST

(51) 1. Sheet 2. Back-surface primer layer 3. Base material sheet 4. Picture pattern layer 5. Adhesive layer 6. Transparent resin layer 7. Primer layer 8. Surface-protecting layer 9. Plane part having an irregular shape formed by an extender pigment, etc., on the surface thereof 10. Wood-grain vessel pattern 11. Fine particles A 12. Fine particles B 13. Gloss-adjusting layer