JP2018052043A - Mirror surface decorative sheet and molded product - Google Patents

Abstract

[PROBLEMS] To adhere to an adherend following the shape of an adherend having a complicated shape or corners, exhibit excellent bending workability without causing cracks or changes in appearance, and form a sheet. To provide a dark-colored decorative sheet having good specularity even after winding, and to provide a molded article having the same. A mirror surface decorative sheet having a base sheet and a surface protective layer, wherein the base sheet is a polyolefin base sheet containing a thermoplastic elastomer, and the surface protective layer comprises an ionizing radiation curable resin composition. A cured product of the product, the crack generation elongation measured by a predetermined method of the surface protective layer is more than 20% and 100% or less, and the back surface of the mirror surface decorative sheet measured in accordance with JIS B0601: 2001 A mirror surface decorative sheet having a ten-point average roughness (Rz JIS) of 3 μm or more and 15 μm or less and an L* value of 50 or less in the L*a*b* color system defined in JIS Z8781-4:2013. , and a molded product having the same. [Selection drawing] Fig. 1

Description

  The present invention relates to a mirror surface decorative sheet and a molded article using the same.

  A member having a curved surface, such as interior and exterior parts for automobiles, home appliances, etc., is attached with a decorative sheet that gives a beautiful appearance by applying a color, pattern, unevenness, etc. to a plastic sheet as a base material. Polyvinyl chloride (PVC) is mainly used as a raw material for the substrate. However, in recent years, in order to reduce the processing cost related to waste processing, an alternative to a material having a small environmental load has been demanded, and the use of a polyolefin-based resin has been studied. Further, these members are required to have a specularity due to the recent trend toward high-end products by consumers, and in particular, those that maintain the specularity even after processing are required.

A cosmetic sheet comprising a polyolefin resin sheet as a base material, and having a mirror surface and processability, and comprising a base material sheet made of polypropylene resin and a surface protective layer that is a cured product of an ionizing radiation curable resin composition A sheet has been proposed (for example, Patent Document 1). In Patent Document 1, the thickness of the base sheet is 150 to 500 μm, the surface ten-point average roughness (Rz _JIS ) is 5 μm or less, the thickness of the surface protective layer is 7 to 17 μm, It is described that a decorative sheet having specularity and workability can be obtained when the crack occurrence elongation measured by the method is 10 to 20%.

  Moreover, in order to make it hard to produce an abrasion and a wrinkle after winding up a roll, it is proposed to give a roughening process to the back surface of a decorating sheet (decorative sheet) (for example, patent document 2).

International Publication No. 2015/141781 JP2012-11676A

A decorative sheet having a mirror surface property is used, for example, for interior and exterior parts for automobiles. However, although the decorative sheet described in Patent Document 1 can be used for 2R bending, it is bent for use in a molded product having a more severe curved surface or a complicated curved surface shape, such as an automotive interior / exterior part. It has been desired to further improve the performance. For example, when attaching a decorative sheet to a covering material having a corner portion from the surface to the side surface so as to bend the decorative sheet following the corner portion, or to wrap the decorative sheet up to the surface, side surface and back side of the covering material Even when it is attached to the surface, it is required that the shape followability is high and cracks and appearance changes do not occur.
According to the method described in Patent Document 2, the decorative sheet is less likely to cause dents and scratches on the surface due to the inclusion of foreign matter when winding the roll, and is less likely to cause scratches and wrinkles due to the close contact between the front and back surfaces. Is obtained. However, in a decorative sheet using a soft base sheet having a highly specular surface protective layer and made of a polyolefin resin or the like as the base material, the back surface has irregularities on the surface protective layer when the sheet is wound up. Specularity may be reduced due to shaping. In particular, in a dark-colored decorative sheet such as black or dark brown, a reduction in specularity due to the formation of irregularities is noticeably observed visually.
Although it is effective to harden the surface protective layer to prevent the unevenness of the back surface of the sheet from being formed on the surface protective layer, peeling and cracking are likely to occur during bending. For this reason, in a decorative sheet having specularity, it has been difficult to achieve both excellent bending workability and specularity.

  Under such circumstances, the present invention can be applied following a complicated shape or a shape of an adherend having a corner portion, and has excellent bending workability without causing cracks or appearance changes. It is an object of the present invention to provide a dark decorative sheet having good specularity even after winding of the sheet, and a molded product having the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the problem can be solved by the following invention. That is, this invention provides the following mirror surface decorative sheet and a molded article having the same.

1. A mirror surface decorative sheet having a base sheet and a surface protective layer, wherein the base sheet is a polyolefin base sheet containing a thermoplastic elastomer, and the surface protective layer is a cured product of an ionizing radiation curable resin composition. The crack generation elongation measured by the following method of the surface protective layer is more than 20% and 100% or less, and the ten-point average roughness of the back surface of the mirror-finished decorative sheet measured according to JIS B0601: 2001 _{(Rz JIS)} is 3μm or more and 15μm or less, and, JIS Z8781-4: ^{L *} value in ^{the L} * ^a * ^{b *} color system defined in 2013 is 50 or less, the specular decorative sheet.
(Measurement of crack elongation)
A strip-shaped test piece according to JIS K7127: 1999 is prepared as a decorative sheet, and the test piece is used at 23 ° C. ± 2 ° C. under the conditions of a tensile speed of 200 mm / min and a chuck distance of 100 mm. After pulling at an arbitrary elongation, the inside of the chuck is colored with a whiteboard marker, and the colored portion is wiped off with a cloth. It was.
2. The mirror surface decorative sheet according to 1 above, wherein the 20 ° gloss measured in accordance with JIS Z8741-1997 is 40% or more for the surface protective layer surface of the mirror surface decorative sheet.
3. The mirror surface decorative sheet according to 1 or 2, wherein the surface protective layer has a thickness of 6 to 20 µm.
4). The specular decorative sheet according to any one of 1 to 3, wherein the base sheet is a colored base sheet.
5. The mirror surface decorative sheet with an adhesive layer which has an adhesive layer in the back surface of the mirror surface decorative sheet of any one of said 1-4.
6). The molded article which has a mirror surface decorative sheet of any one of said 1-4 on an adherend.

  ADVANTAGE OF THE INVENTION According to this invention, while having the outstanding bending workability, the dark mirror surface decorative sheet which has the favorable mirror surface property after winding of a sheet | seat, and a molded article which has this can be obtained.

It is a schematic diagram which shows the cross section of one aspect of the mirror surface decorative sheet of this invention. It is a schematic diagram which shows the cross section of another aspect of the mirror surface decorative sheet of this invention.

[Mirror finish sheet]
The mirror surface decorative sheet of the present invention (hereinafter sometimes simply referred to as “decorative sheet”) is a mirror surface decorative sheet having a base sheet and a surface protective layer, and the base sheet is a polyolefin containing a thermoplastic elastomer. It is a base sheet, the surface protective layer is a cured product of an ionizing radiation curable resin composition, and the crack generation elongation measured by the following method of the surface protective layer is more than 20% and 100% or less, JIS L ^* a ^{* in which} the ten-point average roughness (Rz _JIS ) of the back surface of the mirror-finished decorative sheet measured in accordance with B0601: 2001 is 3 μm or more and 15 μm or less, and is defined by JIS Z8781-4: 2013 The L ^* value in the b ^* color system is 50 or less.
(Measurement of crack elongation)
A strip-shaped test piece according to JIS K7127: 1999 is prepared as a decorative sheet, and the test piece is used at 23 ° C. ± 2 ° C. under the conditions of a tensile speed of 200 mm / min and a chuck distance of 100 mm. After pulling at an arbitrary elongation, the inside of the chuck is colored with a whiteboard marker, and the colored portion is wiped off with a cloth. It was.

The layer structure of the decorative sheet of the present invention is not particularly limited as long as it has a surface protective layer on the base sheet.
In the decorative sheet of the present invention, the surface is a so-called “front surface”, and when the decorative sheet of the present invention is used by being laminated on an adherend or the like, a surface in contact with the adherend Is a surface on the opposite side and is a surface visually recognized after lamination. In the present specification, the direction of the surface of the decorative sheet of the present invention may be referred to as “front” or “up”, and the opposite side may be referred to as “back” or “down”.

The decorative sheet of the present invention will be described with reference to FIGS. 1 and 2. FIG.1 and FIG.2 is a schematic diagram which shows the cross section of one aspect | mode of the decorative sheet of this invention. A decorative sheet 10 shown in FIG. 1 has a base sheet 1 and a surface protective layer 2 in this order. A primer layer may be provided between the base sheet 1 and the surface protective layer 2. Moreover, the decorative sheet shown in FIG. 2 has the base material sheet 1, the primer layer 3, the surface protective layer 2, and the masking film 5 in this order, and the side having the primer layer and the surface protective layer of the base material sheet. The back side primer layer 4 is provided on the opposite side (hereinafter sometimes simply referred to as the back side).
As shown in FIGS. 1 and 2, the “surface 10 </ b> S” of the mirror surface decorative sheet 10 refers to the outermost surface on the side opposite to the base material sheet 1 side of the surface protective layer 2.
Further, the “back surface 10R” of the mirror surface decorative sheet 10 refers to the outermost surface opposite to the front surface 10S of the decorative sheet 10. In the form in which the back surface primer layer 4 is not provided on the base material sheet as shown in FIG. 1, the outermost surface 1 </ b> R (also referred to as the back surface of the base material sheet 1) opposite to the surface protective layer 2 of the base material sheet 1 is the decorative sheet 10. Matches the back side. Moreover, in the form in which the back surface primer layer 4 is provided on the base material sheet as shown in FIG. 2, the outermost surface 4R (also referred to as the back surface of the back surface primer layer 4) on the opposite side of the back surface primer layer 4 from the surface protective layer 2 is a decorative sheet. It corresponds to the back side of 10.

The mirror surface decorative sheet of the present invention having the above-described configuration is excellent in bending workability, can be attached following the shape of an adherend having a complicated shape or corner portion, and at the time of bending work. Cracks and appearance changes do not occur.
In addition, a decorative sheet using a polyolefin base sheet containing a thermoplastic elastomer is excellent in bending workability, but if the base sheet is soft, the unevenness on the back side is easily formed on the surface protective layer of the decorative sheet after winding. , Mirror finish tends to be lowered. Furthermore, the dark decorative sheet has a problem that the reduction in specularity due to the formation of irregularities is conspicuous. However, the cracking elongation of the surface protective layer measured by the above method is more than 20% and not more than 100%, so even if it is a decorative sheet using the soft base sheet, the decorative sheet after winding up the sheet It is possible to prevent unevenness on the back surface of the material from being formed on the surface protective layer. Moreover, even if the irregular shape is once formed on the surface protective layer, it recovers with the lapse of time by the self-repairing function of the surface protective layer, so that good mirror surface properties can be maintained even after winding.

In the present invention, the “mirror surface decorative sheet” refers to a sheet having a 20 ° gloss measured by a method according to JIS Z8741-1997, preferably 40% or more, on the surface protective layer surface of the decorative sheet. The value of the 20 ° gloss is a specular glossiness (special glossiness, hereinafter referred to as “special glossiness” measured at an angle of 20 ° at any five locations of the surface protective layer using a gloss measuring device (“micro gloss” manufactured by BYK Gardner). Average value) (also referred to as “gross” or “gross value”).
Since the decorative sheet of the present invention has excellent specularity, the gloss value measured at an angle of 20 °, which is a severer condition than the normal measurement conditions (angle of 60 °), is used for the evaluation of the specularity. ing. That is, when the specularity is very excellent, the measurement of the angle 60 ° saturates the gloss, that is, the specular glossiness, and the correlation between the sense of specular gloss based on vision and the measured value is significant. This is because the difference decreases and no significant difference is seen in the numerical values. The 20 ° gloss is more preferably 50% or more, and further preferably 60% or more.

  Hereinafter, the decorative sheet of the present invention will be specifically described using the decorative sheet having the layer structure of FIGS. 1 and 2 as a representative example.

The ten-point average roughness (Rz _JIS ) of the back surface measured according to JIS B0601: 2001 of the decorative sheet of the present invention is 3 μm or more and 15 μm or less. When the ten-point average roughness (Rz _JIS ) of the back surface of the decorative sheet 10 is 3 μm or more, the base sheet 1 and the specular decorative sheet when the base sheet 1 is formed and when the specular decorative sheet 10 is wound up The air is entangled between the surface 10 and the back surface that are in contact with each other, the facing surface and the back surface are inadvertently brought into close contact with each other, and the rewinding is difficult. It is easy to suppress a phenomenon (so-called “blocking”) that shifts to the (surface) side. On the other hand, if the 10-point average roughness (Rz _JIS ) of the back surface of the decorative sheet 10 is 15 μm or less, the surface (surface protective layer) of the decorative sheet 10 comes into contact with the relatively smooth back surface after winding the sheet. Moreover, the specularity fall by the unevenness | corrugation of a back surface being shape | molded by the surface protective layer can be suppressed. In particular, since the decorative sheet of the present invention is a dark color, a decrease in specularity due to the formation of irregularities on the surface protective layer is conspicuous, so that the effects of the present invention can be effectively exhibited. When the Rz _JIS is larger than 15 μm, it is impossible to prevent a decrease in specularity due to the unevenness on the back surface of the decorative sheet being formed on the surface protective layer after winding the sheet. In addition, since the blocking effect is saturated, there is no need to dare to raise Rz _JIS any more.
From the viewpoint of obtaining excellent specularity and suppressing blocking when the decorative sheet is wound, the ten-point average roughness (Rz _JIS ) is preferably 3 to 13 μm, and preferably 3 to 10 μm. More preferred.
The ten-point average roughness (Rz _JIS ) of the back surface of the decorative sheet can be adjusted by, for example, the material and surface shape of the roll used when forming the sheet. The ten-point average roughness (Rz _JIS ) is measured in accordance with JIS B0601: 2001, and is an average value measured at any five locations using a contact-type surface roughness meter.

  In this specification, the symbols “X to Y” attached to the numerical ranges are used to mean “X or more and Y or less”. In particular, when excluding the upper limit value and / or the lower limit value, for example, “exceeding X over Y”, “exceeding X and under Y”, “exceeding X over Y”, etc.

Moreover, the arithmetic mean roughness (Ra) of the back surface measured according to JIS B0601: 2001 of the mirror surface decorative sheet of the present invention is preferably 0.3 μm or more and 2 μm or less. When the arithmetic average roughness (Ra) of the back surface of the decorative sheet is 0.3 μm or more, it is easy to suppress blocking when the specular decorative sheet is wound. On the other hand, if the Ra is 2 μm or less, the surface (surface protective layer) of the decorative sheet comes into contact with the relatively smooth back surface after winding the sheet, so that the back surface unevenness is formed on the surface protective layer. It is possible to suppress a decrease in specularity due to. From the viewpoint of obtaining excellent specularity and suppressing blocking when the decorative sheet is wound, the arithmetic average roughness (Ra) is preferably 0.3 to 1.8 μm, preferably 0.3 to More preferably, it is 1.4 μm.
The arithmetic average roughness (Ra) of the back surface of the decorative sheet can be measured by the same method as the ten-point average roughness (Rz _JIS ).

The mirror surface decorative sheet of the present invention is a dark sheet having the L ^* value of 50 or less. The L ^* value is obtained by spectroscopic analysis of the L ^* value in the CIE (International Lighting Commission) L ^* a ^* b ^* color system defined by JIS Z8781-4: 2013 on the surface protective layer surface of the mirror decorative sheet of the present invention. It is a value measured using a colorimeter. The smaller the value, the darker the color. In the dark decorative sheet having an L ^* value of 50 or less, since the specular deterioration is conspicuous when the surface protective layer has irregularities on the back surface of the sheet, the effect of the present invention can be exhibited more effectively. The L ^* value is preferably 45 or less, more preferably 40 or less, and still more preferably 30 or less.
Examples of the method of setting the L ^* value of the decorative sheet to 50 or less include a method of coloring the base sheet or a dark colorant in at least one of the layers constituting the decorative sheet. . In the decorative sheet of the present invention, a method using a colored base sheet is preferable from the viewpoint of imparting concealment and improving design properties.

The mirror surface decorative sheet of the present invention preferably has a 2% modulus of 5 to 30 N / 15 mm, more preferably 7 to 25 N / 15 mm. When the 2% modulus is within the above range, a decorative sheet having excellent processability and specularity can be obtained.
In this specification, the 2% modulus is measured at a tensile rate of 200 mm / min and a distance between chucks of 100 mm in a room temperature environment using a strip-shaped test piece of 15 mm × 140 mm by a measuring method based on JIS K7127: 1999. The value of the load (N / 15 mm) measured under the condition of elongation 2%.
The decorative sheet of the present invention is implemented in the form of a decorative sheet with a masking film further having a masking film on the surface protective layer and / or in the form of a decorative sheet with an adhesive layer further having an adhesive layer on the back side. Although cracking elongation is obtained, it is a value measured in the state which does not have the masking film or adhesive bond layer mentioned later.

  In this specification, unless otherwise specified, room temperature is 23 ° C. ± 5 ° C., and room temperature environment means a laboratory environment where the temperature is 23 ° C. ± 5 ° C.

  The 2% modulus of the decorative sheet of the present invention can be adjusted by adjusting the type or composition of the resin constituting the base sheet, the thickness of the base sheet, and the like. Regarding the resin constituting the base sheet, for example, a method of mixing a plurality of polyolefin resins constituting the base sheet and adjusting the blending ratio, and the type and blending amount of the thermoplastic elastomer contained in the base sheet The method of adjusting is mentioned. Further, when the thickness of the base sheet is reduced, the 2% modulus is decreased, and when the thickness is increased, the 2% modulus is increased.

  Alternatively, the 2% modulus of the decorative sheet can be adjusted by adjusting the physical properties of the surface protective layer. Specifically, a method of appropriately adjusting the coating amount of the ionizing radiation curable resin composition forming the surface protective layer and the radiation intensity of the ionizing radiation when forming the surface protective layer can be mentioned. The 2% modulus increases as the coating amount increases and the radiation intensity increases. Moreover, the method of mixing the ionizing radiation curable resin which forms a surface protective layer, adjusting the compounding ratio suitably, and adjusting the hardness of a surface protective layer is also mentioned.

(Substrate sheet)
The base material sheet used for the decorative sheet of the present invention is a polyolefin base material sheet containing a thermoplastic elastomer. When the base sheet contains a thermoplastic elastomer, the decorative sheet of the present invention is provided with flexibility, and excessive elongation, shrinkage, and return deformation during bending of the sheet are suppressed, and excellent bending workability is achieved. It becomes a sheet.
Examples of the thermoplastic elastomer include thermoplastic elastomers such as polyolefins such as polyethylene and polypropylene; styrenes; polyesters; polyurethanes. Among these, polyolefin-based thermoplastic elastomers are preferable, and polypropylene-based thermoplastic elastomers are more preferable.
Although there is no restriction | limiting in particular in content of the thermoplastic elastomer in a base material sheet, From a viewpoint of bending workability, heat resistance, and intensity | strength, Preferably it is the range of 5-80 mass%, More preferably, it is 10-60 mass%. It is a range.

  The base sheet used in the present invention is not particularly limited as long as it is a base sheet containing a thermoplastic elastomer and a polyolefin resin as main components. The “main component” refers to a component that occupies 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more of all components constituting the base sheet. Usually, a film composed of a thermoplastic elastomer and a polyolefin resin may be used.

It does not specifically limit as polyolefin-type resin, What is normally used in the field | area of a decorative sheet can be used. Examples of such polyolefin resins include polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-propylene-butene copolymer. Examples include coalescence. Among these, a polypropylene resin is preferable from the viewpoint of flexibility.
By adopting the polypropylene resin, even if the base sheet is thin, it is difficult to pick up so-called duck such as uneven application of glue (adhesive) or unevenness of the surface of the adherend, and excellent specularity can be obtained. Moreover, it is excellent in production efficiency, and it is also possible to suppress an increase in material costs or transportation costs.

  The polypropylene resin is preferably a homopolypropylene resin, a random polypropylene resin, a block polypropylene resin, a polypropylene resin having a polypropylene crystal part, or an α-olefin copolymer having 2 to 20 carbon atoms other than the polypropylene resin having a polypropylene crystal part. Can be mentioned. Other propylene-α-olefin copolymers containing 15 mol% or more of ethylene, 1-butene, 1-hexene, 1-octene, 3-methyl-1-butene, 4-methyl-1-pentene, etc. Propylene copolymers, ethylene-propylene-butene copolymers and the like are also preferred.

  As the polypropylene resin, it is preferable to use a crystalline resin having a glass transition point (Tg) of −50 to 70 ° C. and a melting point (Tm) of 130 to 220 ° C. If the polypropylene resin constituting the base sheet is a crystalline resin, it has a stable crystal structure as long as it is below the melting point (Tm) even in a temperature range higher than the glass transition temperature (Tg), so flexibility due to temperature changes. Change in temperature, that is, the temperature dependency of flexibility is low. For example, when a decorative sheet is heated (50 to 120 ° C.) while being wrapped on an adherend, uneven application of glue (adhesive) or Without picking up so-called duck, such as unevenness on the surface of the dressing material, the mirror surface property does not deteriorate after sticking to the adherend material, and even if temperature unevenness due to local heating occurs, excellent mirror surface property Can be maintained.

  The glass transition point (Tg) of the polypropylene resin as the crystalline resin is preferably −50 to 70 ° C. If the glass transition point (Tg) is lower than −50 ° C., there is a possibility that excellent specularity may not be obtained, and if it exceeds 70 ° C., specularity may not be obtained or heat resistance may not be obtained. From the viewpoint of obtaining excellent specularity and heat resistance, it is more preferably -20 to 50 ° C.

  Here, the glass transition point (Tg) is a value measured according to JIS K7121-1987. Specifically, the polypropylene resin is heated from room temperature at a rate of 20 ° C./min, the calorific value is measured with a differential scanning calorimeter (DSC), an endothermic curve diagram or an exothermic curve diagram is created, and an inflection point is created. An extension line is drawn on each of the front and rear straight lines, and the intersection of the 1/2 straight line between the two extension lines and the endothermic curve or exothermic curve is defined as Tg.

  The melting point (Tm) of the polypropylene resin as the crystalline resin is preferably 130 to 220 ° C. If the melting point (Tm) is 130 ° C. or higher, excellent specularity can be obtained. Moreover, if it is 220 degrees C or less, the outstanding workability will be acquired also when processing into the adherend which has a curved-surface shape especially. From the viewpoint of obtaining excellent specularity and workability, the melting point (Tm) of the polypropylene resin is more preferably 130 to 200 ° C.

  Here, the melting point (Tm) is a value measured in accordance with JIS K7121-1987. Specifically, the polypropylene resin is heated from room temperature at a rate of 10 ° C / min, heated to a temperature 30 ° C higher than the end of the melting peak, maintained for 10 minutes, and then cooled to 40 ° C at 10 ° C / min. In the DSC curve obtained by repeating the same heating and cooling again, the temperature at the top of the melting peak is defined as the melting point (Tm). When there are a plurality of endothermic peaks in the DSC curve, the apex temperature of the endothermic peak with the maximum area is adopted.

An additive may be blended in the resin material used for forming the base sheet, if necessary. Examples of the additive include a filler, a flame retardant, an antioxidant, a lubricant, a foaming agent, and a weathering agent.
Among the above additives, from the viewpoint of obtaining excellent processability, inorganic fillers such as calcium carbonate, barium sulfate, clay and talc; ultraviolet absorbers (UVA), hindered amine light stabilizers for improving weather resistance It is preferable to contain a weathering agent such as (HALS). The content of these inorganic fillers is preferably in the range of 1 to 60% by mass with respect to the resin material.

  50-250 micrometers is preferable and, as for the thickness of a base material sheet, 90-150 micrometers is more preferable. When the thickness of the base sheet is within the above range, a mirror surface decorative sheet excellent in specularity and workability can be obtained.

From the viewpoint of obtaining a dark mirror-finished decorative sheet, the substrate sheet used in the present invention is preferably a colored substrate sheet. When the base sheet is colored, it is possible to conceal the base of the covering material of the decorative sheet, and at the same time, excellent design properties are obtained.
As the colored base sheet, for example, a base sheet containing a colorant can be used. The colorant that can be used for the colored base sheet is not particularly limited as long as it can give the predetermined L * value to the decorative sheet, but a dark colorant is preferable. For example, in addition to inorganic pigments such as carbon black (black) and iron black, organic pigments and dyes can be used alone or in combination of two or more.
In the case of producing a black mirror surface decorative sheet having a low L * value, it is preferable to use a black pigment such as carbon black or iron black as a colorant.
The amount of the colorant used is an amount that can give the predetermined L ^* value, and is not particularly limited as long as it does not decrease the film forming property and mechanical strength when the substrate sheet is obtained by extrusion molding. Absent.

From the viewpoint of obtaining a dark specular decorative sheet, the L ^* value in the L ^* a ^* b ^* color system defined by JIS Z8781-4: 2013 of the base sheet is preferably 50 or less, more preferably 45 or less, more preferably 40 or less, and even more preferably 30 or less. The L ^* value of the base sheet can be measured by the same method as described above.

When the base material sheet is the lowermost layer of the decorative sheet, the 10-point average roughness (Rz _JIS ) of the back surface of the base material sheet measured according to JIS B0601: 2001 is set to 3 μm or more and 15 μm or less.
When the ten-point average roughness (Rz _JIS ) of the back surface of the base material sheet is 3 μm or more, it is easy to suppress blocking when the specular decorative sheet is wound. On the other hand, if the 10-point average roughness (Rz _JIS ) of the back surface of the base sheet is 15 μm or less, the surface of the decorative sheet (surface protective layer) comes into contact with the relatively smooth back surface after winding the sheet. It is possible to suppress a decrease in specularity due to the unevenness on the back surface being formed on the surface protective layer. When the base sheet is the lowermost layer of the decorative sheet, if the Rz _JIS is larger than 15 μm, it is impossible to prevent a decrease in specularity due to the unevenness on the back surface of the decorative sheet being formed on the surface protective layer after winding the sheet. .
From the viewpoint of obtaining excellent specularity and suppressing blocking when the decorative sheet is wound, the ten-point average roughness (Rz _JIS ) of the back surface of the base sheet is preferably 3 to 13 μm. More preferably, it is 10-10 micrometers.
The ten-point average roughness (Rz _JIS ) of the back surface of the base sheet can be adjusted by, for example, the material and surface shape of the roll used when forming the base sheet. Ten-point average roughness (Rz _JIS ) can be measured by the same method as described above.

(Primer layer)
A primer layer may be provided between the base sheet and the surface protective layer. By providing the primer layer, the adhesion between the base sheet and the surface protective layer can be improved, the workability can be improved, and blocking can be prevented in the production process.

  A primer layer is comprised by the resin composition containing binder resin and a mat agent, for example. The binder resin is not particularly limited. For example, urethane resin, acrylic resin, urethane / acrylic copolymer, polyester resin, epoxy resin, vinyl chloride / vinyl acetate copolymer, chlorinated polypropylene resin, chlorinated polyethylene resin, etc. Is preferred. Among the above, one or more selected from the group consisting of urethane resin, acrylic resin, urethane / acrylic copolymer, and polyester resin is preferable, and one or more selected from the group consisting of urethane / acrylic copolymer and polyester resin Is more preferable. In addition, from the viewpoint of obtaining excellent adhesion and specularity, a two-component curable resin containing the above resin as a main component and isocyanate or the like as a curing agent is preferable.

  As the isocyanate curing agent, a conventionally known compound may be used as appropriate, for example, aromatics such as 2,4-tolylene diisocyanate (TDI), xylene diisocyanate (XDI), naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate. Isocyanate or poly, such as 1,6-hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), methylene diisocyanate (MDI), hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, etc. Isocyanates are used. In addition, adducts or multimers of these various isocyanates, for example, adducts of tolylene diisocyanate, tolylene diisocyanate trimers, and the like are also used.

  In order to prevent blocking in the production process, the primer layer preferably contains a matting agent. By including a matting agent in the primer layer, it is possible to prevent blocking from occurring when the primer layer is once wound up in a roll shape after forming the primer layer on the base sheet. Preferred examples of the matting agent include inorganic particles such as alumina, silica, kaolinite, iron oxide, diamond, and silicon carbide, and organic particles such as acrylic resin, urethane resin, nylon resin, polypropylene resin, and urea resin. Any one type may be used, or two or more types may be used in combination.

  Examples of the shape of the matting agent include a sphere, an ellipsoid, a polyhedron, a scale shape, and the like. Although there is no particular limitation, a spherical shape is preferable in terms of obtaining specularity.

  The average particle size of the matting agent is preferably 0.5 to 8 μm, and more preferably 1 to 5 μm. When the average particle diameter is within the above range, excellent specularity can be obtained. Here, the average particle size is a volume-based particle size measured by laser diffraction type or laser scattering type particle size distribution measurement.

  The content of the matting agent is preferably 0.5 to 30 parts by mass, more preferably 1 to 25 parts by mass, and further preferably 3 to 20 parts by mass with respect to 100 parts by mass of the binder resin. preferable. When the content is within the above range, excellent adhesion can be obtained.

  In the primer layer, additives other than the matting agent may be blended as necessary. Examples of the additive include a filler, a flame retardant, an antioxidant, a lubricant, a foaming agent, and a weathering agent. Among the additives, it is preferable to contain a weathering agent such as an ultraviolet absorber (UVA) or a hindered amine light stabilizer (HALS) in order to improve weatherability. As UVA, a triazine-based ultraviolet absorber that has a high ultraviolet absorbing ability and is not easily deteriorated by high energy such as ultraviolet rays is more preferable.

  The thickness of a primer layer is about 0.5-20 micrometers normally, and 1-10 micrometers is preferable. When the thickness of the primer layer is within the above range, excellent adhesion and specularity can be obtained.

Moreover, the ten-point average roughness (Rz _JIS ) of the surface measured in accordance with JIS B0601: 2001 of the primer layer is preferably 5 μm or less. When the thickness is 5 μm or less, excellent specularity can be obtained. From the viewpoint of obtaining excellent specularity and workability, the ten-point average roughness (Rz _JIS ) is more preferably 1 to 5 μm, and further preferably 2.5 to 5 μm. The ten-point average roughness (Rz _JIS ) of the surface of the primer layer can be adjusted by changing the average particle size, content, etc. of the matting agent. Ten-point average roughness (Rz _JIS ) can be measured by the same method as described above.

(Surface protective layer)
The surface protective layer is an ionizing radiation curable resin that imparts surface characteristics such as weather resistance, stain resistance, scratch resistance, solvent resistance, and heat resistance to the decorative sheet of the present invention, and also provides excellent specularity. It is a layer composed of a cured product of the composition.

  The material constituting the surface protective layer is constituted by a cured product of an ionizing radiation curable resin composition containing an ionizing radiation curable resin. Here, the ionizing radiation curable resin composition is a resin composition that is cured by irradiating with ionizing radiation, and the ionizing radiation has an energy quantum capable of polymerizing or crosslinking molecules among electromagnetic waves or charged particle beams. In addition to ultraviolet rays (UV) or electron beams (EB), electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as α-rays and ion rays are also used.

  The ionizing radiation curable resin contained in the ionizing radiation curable resin composition is appropriately selected from polymerizable monomers and polymerizable oligomers (or prepolymers) conventionally used as ionizing radiation curable resins. be able to.

  For example, polymerizable monomers such as monofunctional (meth) acrylate and polyfunctional (meth) acrylate, urethane (meth) acrylate oligomer, epoxy (meth) acrylate oligomer, polyester (meth) acrylate oligomer, polyether (meth) acrylate oligomer Polymerizable oligomers such as acrylic (meth) acrylate oligomers, or prepolymers can be used alone or in combination of two or more.

  In the present invention, a polymerizable oligomer is preferably used as the ionizing radiation curable resin, and a polyfunctional polymerizable oligomer having 2 or more functional groups is preferable. From the viewpoint of obtaining a desired crack generation elongation, the weight average molecular weight of the oligomer is preferably 500 to 8,000, more preferably 1,000 to 7,000, and still more preferably 1,500 to 6,000. is there. The said oligomer may be used individually by 1 type, and in order to adjust the crack generation elongation of the surface protective layer obtained, you may use it in combination of 2 or more type.

  Further, from the viewpoint of adjusting the viscosity of the ionizing radiation curable resin composition and improving the coating suitability, a polymerizable oligomer and a polymerizable monomer can be used in combination.

  When an ultraviolet curable resin is used as the ionizing radiation curable resin, it is desirable to add about 0.1 to 5 parts by mass of the photopolymerization initiator with respect to 100 parts by mass of the resin. The initiator for photopolymerization can be appropriately selected from those conventionally used, and is not particularly limited. For example, the initiator for photopolymerization such as benzoin, acetophenone, phenylketone, benzophenone, and anthraquinone An agent is preferably mentioned.

  Moreover, as a photosensitizer, p-dimethylbenzoic acid ester, tertiary amines, a thiol type sensitizer, etc. can be used, for example.

  The ionizing radiation curable resin used in the present invention is preferably an electron beam curable resin. In the case of an electron beam curable resin, solvent-free is possible, which is more preferable from the viewpoint of environment and health, and does not require a photopolymerization initiator, provides stable curing characteristics, and excellent surface characteristics. This is because

  In the ionizing radiation curable resin composition, various additives such as silicone components, wear-resistant fillers, mat-forming fillers, fillers such as scratch-resistant fillers, UV absorbers, and light stabilizers are used to improve weather resistance. Weathering agents such as agents can be included.

  The silicone component refers to a component having in its molecule a structure formed by alternately bonding silicon having an organic group and oxygen. As a silicone component, specifically, a silicone oil having a polysiloxane skeleton as a main component, an organic group having reactivity such as an amino group, a vinyl group, an epoxy group, a carboxyl group, an acrylic group, and a methacryl group at the side chain or terminal. Reactive silicone introduced with a group; non-reactive silicone introduced with a non-reactive organic group such as an alkyl group, an ether group or a higher fatty acid at the side chain or terminal; side of an organic resin, ionizing radiation curable resin, etc. Examples thereof include a silicone-modified resin whose chain or terminal is modified with silicone. By adding the silicone component, the leveling property when coating the ionizing radiation curable resin composition is improved and a uniform coating film can be formed. In addition, the silicone component floats on the surface of the coating film. Due to the rising action, a decrease in planar smoothness caused by the ionizing radiation curable resin composition soaking into the primer layer is suppressed, so that the specularity can be improved.

Among these, the reactive silicone reacts and integrates with the ionizing radiation curable resin when the ionizing radiation curable resin composition is cured, and it is difficult to cause poor appearance due to bleeding out. It is preferable at the point which can hold | maintain.
The types of reactive silicone include modified silicone oil side chain type, modified silicone oil both end type, and modified silicone oil side chain both end type, depending on the organic group to be introduced, amino-modified, epoxy-modified, mercapto-modified. , Carboxyl modification, carbinol modification, phenol modification, methacryl modification, heterogeneous functional group modification, and the like.

  It is preferable that content of a silicone component is 0.1-2 mass% with respect to the ionizing radiation curable resin contained in an ionizing radiation curable resin composition. By setting it as the above range, sufficient lubricity can be imparted to the surface, no repelling occurs at the time of coating, the coating surface is not roughened, and stability can be improved. . The content is more preferably 0.2 to 1% by mass.

  As the ultraviolet absorber, either inorganic or organic can be used. As the inorganic ultraviolet absorber, titanium oxide, cerium oxide, zinc oxide or the like having an average particle diameter of about 5 to 120 nm can be preferably used. Moreover, as an organic type ultraviolet absorber, a benzotriazole type, a triazine type, a benzophenone type, a salicylate type, an acrylonitrile type etc. can be mentioned preferably, for example. Of these, triazine-based ultraviolet absorbers are preferred because they have high ultraviolet-absorbing ability and are not easily deteriorated by high energy such as ultraviolet rays. Further, as the ultraviolet absorber, an ultraviolet absorber having an ionizing radiation reactive group in the molecule can be used.

  Preferred examples of the light stabilizer include hindered amine light stabilizers (HALS). Moreover, the light stabilizer which has the (meth) acryloyl group which is an ionizing-radiation reactive group in a molecule | numerator can also be used.

  By using the above ultraviolet absorber, light stabilizer and the like as a weathering agent, stable weatherability can be obtained without causing the weathering agent to bleed out.

  In addition, the ionizing radiation curable resin composition, as various additive components, for the purpose of improving the concealability of the surface protective layer in the resulting decorative sheet, preventing yellowing of the base sheet and improving light resistance, An inorganic colorant such as aluminum paste or carbon black can be added as appropriate.

The surface protective layer, which is a cured product of the ionizing radiation curable resin composition, has a crack generation elongation measured by the following method of more than 20% and not more than 100%.
(Measurement of crack elongation)
Using a decorative sheet, a strip-shaped test piece conforming to JIS K7127: 1999 was prepared, and the test piece was measured at 23 ° C. ± 2 ° C. using a tensile tester with a tensile speed of 200 mm / min and a chuck distance of 100 mm. After pulling at an arbitrary elongation under certain conditions, the inside of the chuck is colored with a whiteboard marker, and the colored part is wiped off with a cloth. It was set as the elongation.
The decorative sheet of the present invention is implemented in the form of a decorative sheet with a masking film further having a masking film on the surface protective layer and / or in the form of a decorative sheet with an adhesive layer further having an adhesive layer on the back side. Although cracking elongation is obtained, it is a value measured in the state which does not have the masking film or adhesive bond layer mentioned later.

  In the above method for measuring the crack occurrence elongation, Pentel knuckle whiteboard markers, blue, round core, and middle character were used as whiteboard markers. Further, the coloring between the chucks was colored throughout the chucks after being pulled.

When the crack generation elongation of the surface protective layer is 20% or less, the surface of the decorative sheet is cracked. On the other hand, when the crack generation elongation exceeds 100%, the surface of the decorative sheet is too soft, and irregularities on the back surface of the decorative sheet are formed at the time of winding the sheet, and the specularity is deteriorated. The crack generation elongation is preferably 25 to 80%, more preferably 25 to 75%, and still more preferably 30 to 60%.
Further, if the crack generation elongation of the surface protective layer is more than 20% and 100% or less, even if the surface protective layer is once shaped with an uneven shape, it is recovered over time by the self-repairing function of the surface protective layer. Even after winding, good specularity can be maintained.

  Adjustment of the crack generation elongation of the surface protective layer can be performed by adjusting the hardness of the surface protective layer. Specifically, for example, it can be carried out by adjusting the number of functional groups, molecular weight, etc. of the ionizing radiation curable resin contained in the ionizing radiation curable resin composition forming the surface protective layer. When the number of functional groups of the ionizing radiation curable resin is increased, the resin becomes hard and the crack generation elongation decreases, and when the number of functional groups is decreased, the resin becomes soft and the crack generation elongation tends to increase. When the molecular weight of the ionizing radiation curable resin is reduced, the resin becomes hard and crack generation elongation decreases, and when the molecular weight of the ionizing radiation curable resin is increased, the resin becomes soft and crack generation elongation tends to increase.

  Moreover, the crack generation elongation of the surface protective layer can be adjusted by adjusting the irradiation intensity of the ionizing radiation when forming the surface protective layer. When the irradiation intensity of ionizing radiation is increased, the surface protective layer is hardened and the crack generation elongation is reduced. On the other hand, when the irradiation intensity of ionizing radiation is weakened, the surface protective layer becomes soft and the crack generation elongation increases. Furthermore, the crack generation elongation of the surface protective layer can also be adjusted by mixing a plurality of ionizing radiation curable resins forming the surface protective layer and adjusting the blending ratio as appropriate to adjust the hardness of the surface protective layer. it can.

  Further, the crack generation elongation can be adjusted by appropriately adjusting the coating amount of the ionizing radiation curable resin composition forming the surface protective layer. Increasing the coating amount decreases the cracking elongation, and decreasing the coating amount increases the cracking elongation.

The thickness of the surface protective layer is preferably 6 to 20 μm. If the thickness of the surface protective layer is 6 μm or more, excellent specularity is obtained, and if it is 20 μm or less, the bending workability is excellent.
From the viewpoint of obtaining excellent specularity and excellent processability, the thickness of the surface protective layer is more preferably 7 to 18 μm, and further preferably 7 to 15 μm.

As described above, the 20 ° gloss measured on the surface of the surface protective layer according to JIS Z8741-1997 is preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more. .
The adjustment of the 20 ° gloss can be performed by adjusting the thickness of the surface protective layer. Specifically, when the thickness of the surface protective layer is reduced, the 20 ° gloss is reduced, and when it is increased, the 20 ° gloss is increased.

(Back primer layer)
The back primer layer is a layer provided as necessary for the purpose of improving the adhesion between the base sheet and various adherends, and is opposite to the side of the base sheet on which the primer layer and the surface protective layer are provided. Is provided on the surface (back surface).

A back surface primer layer is comprised by the resin composition containing binder resin and a mat agent, for example. As the binder resin, those described in the section of the primer layer are preferably mentioned, and are appropriately selected according to the material of the adherend.
Moreover, as a mat agent, what was described by the term of the said primer layer is mentioned preferably, The preferable average particle diameter is the same as the above. The content of the matting agent in the back primer layer is preferably 5 to 70 parts by mass, more preferably 10 to 70 parts by mass with respect to 100 parts by mass of the binder resin.

The thickness of the back primer layer is preferably 0.5 to 5 μm, more preferably 1 to 3 μm. When the thickness is within the above range, excellent adhesion between the base sheet and various adherends can be obtained.
In addition, when the back surface primer layer is provided on the back surface of the base material sheet, the back surface of the back surface primer layer (the surface far from the surface protective layer) corresponds to the back surface of the decorative sheet. The ten-point average roughness (Rz _JIS ) of the back surface of the primer layer is set to 3 μm or more and 15 μm or less.

(Decoration layer)
The decorative sheet of the present invention may further be provided with a decorative layer. The decorative layer gives decorativeness to the decorative sheet of the present invention, and may be a uniformly colored concealing layer (solid printing layer) or print various patterns using ink and a printing machine. The pattern layer formed by this may be sufficient. Alternatively, a combination of a hiding layer and a pattern layer may be used. The decorative layer is usually provided between the base material sheet and the surface protective layer. When the decorative sheet of the present invention has a primer layer, the decorative layer is provided between the base sheet and the primer layer.

By providing a concealing layer, the surface of the adherend can be concealed, and when the base sheet is colored or uneven, the surface color can be adjusted by giving the intended color. .
In addition, by providing a pattern layer, a grain pattern imitating the surface of a rock such as a wood grain pattern, marble pattern (for example, travertine marble pattern), a fabric pattern imitating a texture or cloth pattern, tiled pattern, brickwork A pattern such as a pattern or a combination of these, a parquet, a patchwork, or the like can be applied to the decorative sheet. These patterns are formed by multicolor printing with the usual yellow, red, blue and black process colors, as well as by multicolor printing with special colors prepared by preparing the individual color plates constituting the pattern. Is done.

  As the ink composition used for the decorative layer, a binder resin in which a colorant such as a pigment or a dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, or a curing agent is appropriately mixed is used. The binder resin is not particularly limited. For example, urethane resin, vinyl chloride / vinyl acetate copolymer resin, vinyl chloride / vinyl acetate / acrylic copolymer resin, chlorinated polypropylene resin, acrylic resin, polyester resin, polyamide resin. , Butyral resin, polystyrene resin, nitrocellulose resin, cellulose acetate resin and the like are preferable, and polyurethane resin is more preferable. Any of these binder resins can be used alone or in admixture of two or more.

  Moreover, as a coloring agent, a dark color coloring agent is preferable and what was illustrated as a coloring agent used for a base material sheet is preferable.

  The thickness of the decoration layer is usually about 0.5 to 20 μm, and preferably 1 to 10 μm. If the thickness of a decoration layer exists in the said range, the designability excellent in the decorative sheet can be provided.

(Masking film)
Masking film is a surface protective layer for decorative sheets to prevent scratches when adhering decorative sheets to adherends, transporting molded products obtained by applying and processing decorative sheets, or during construction. It is a film preferably provided on the top. Therefore, the decorative sheet of the present invention can be a decorative sheet with a masking film having a masking film on the surface of the decorative sheet. In addition, the crack generation elongation of a surface protective layer is a value in the state of a decorative sheet without a masking film.

  The masking film usually has a configuration having a masking film substrate and an adhesive layer.

  Preferred examples of the base material for the masking film include polyester films such as polyethylene terephthalate (PET) films; polyolefin films such as polyethylene films and polypropylene films; polycarbonate films and the like.

  There is no restriction | limiting in particular about the thickness of this base material for masking films, It is preferable that it is 10-100 micrometers, and it is more preferable that it is 30-70 micrometers. When the thickness is within the above range, good scratch resistance can be obtained, turning and peeling are unlikely to occur during processing, and cost can be reduced.

  The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer is, for example, an acrylic-based polymer mainly composed of a (meth) acrylic acid ester-based polymer, from the viewpoint of being difficult to peel off during storage, easy to peel off during use, and difficult to leave a pressure-sensitive adhesive residue. In addition to the pressure-sensitive adhesive, rubber-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, and the like are preferable.

  Moreover, 5-40 micrometers is preferable and, as for the thickness of an adhesive layer, 10-30 micrometers is more preferable. When the thickness is within the above range, it is difficult to peel off during storage, it is easy to peel off during use, and the adhesive remains difficult to leave.

(Manufacturing method of decorative sheet)
The method for producing the decorative sheet of the present invention is not particularly limited. For example, (1) a step of forming a base sheet, and (2) an ionizing radiation curable resin composition is applied and cured on the base sheet. And a step of forming a surface protective layer in order. You may perform the process of forming a primer layer and a back surface primer layer in the said base material sheet as needed between a process (1) and a process (2).

<Step (1)>
Step (1) is a step of forming a base sheet.
The base sheet is made of, for example, a resin composition containing a thermoplastic elastomer and a polyolefin-based resin, and a resin composition obtained by adding a colorant for imparting a dark color as desired, and other additives, a calendar method, an inflation method, T It is obtained as a sheet by a method such as die extrusion. Here, uniaxial or biaxial stretching may be performed as necessary.
From the viewpoint of improving the adhesion with the layer in contact with the obtained substrate sheet, the surface may optionally be subjected to an oxidation method such as corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone-ultraviolet treatment method, An easy-adhesion layer may be provided by performing physical or chemical surface treatment such as a sand blasting method or a concavo-convex method such as a solvent processing method.

Between the step (1) and the step (2) described later, a step of forming a primer layer and a back primer layer on the base sheet can be performed as necessary.
The primer layer and the back primer layer are formed by applying the resin composition forming these layers by a known coating method such as a gravure printing method, a bar coating method, a roll coating method, a reverse roll coating method, or a comma coating method. do it. Moreover, when providing both a primer layer and a back surface primer layer, you may form any layer previously.

<Step (2)>
Step (2) is a step of forming a surface protective layer by applying and curing an ionizing radiation curable resin composition on a base film.
The application of the ionizing radiation curable resin composition is a gravure printing method on the surface of the base sheet or the primer layer provided as desired, preferably with a thickness of 6 to 20 μm after curing. , A known method such as a bar coating method, a roll coating method, a reverse roll coating method or a comma coating method, preferably a gravure printing method. The viscosity of the ionizing radiation curable resin composition is not particularly limited as long as it can form an uncured resin layer by applying the ionizing radiation curable resin composition to the surface of the base sheet or primer layer.

Next, the uncured resin layer formed by applying the ionizing radiation curable resin composition is irradiated with ionizing radiation such as an electron beam and ultraviolet rays to cure the uncured resin layer, and the ionizing radiation curable resin composition A surface protective layer which is a cured product of is formed.
When an electron beam is used as the ionizing radiation, the accelerating voltage can be appropriately selected according to the resin used and the thickness of the layer, but it is usually preferable to cure the uncured resin layer at an accelerating voltage of about 70 to 300 kV.

In electron beam irradiation, the higher the acceleration voltage, the greater the transmission capability. Therefore, when using a material that deteriorates due to the electron beam as the base layer, the transmission depth of the electron beam and the thickness of the resin layer are substantially equal. By selecting an accelerating voltage so as to be equal to, it is possible to suppress irradiation of an extra electron beam to the base material sheet, and to minimize deterioration of the base material layer due to the excess electron beam.
The irradiation dose is preferably such that the crosslink density of the resin layer is saturated, usually 5 to 300 kGy (0.5 to 30 Mrad), preferably 10 to 100 kGy (1 to 10 Mrad), more preferably 30 to 70 kGy (3 to 7 Mrad). It is selected in the range.
The electron beam source is not particularly limited. For example, various electron beam accelerators such as a cockroft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type. Can be used.

  When ultraviolet rays are used as the ionizing radiation, those containing ultraviolet rays having a wavelength of 190 to 380 nm are emitted. There is no restriction | limiting in particular as an ultraviolet-ray source, For example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a carbon arc lamp, etc. are used.

The decorative sheet of the present invention thus obtained has excellent bending workability, and particularly has good mirror surface properties even after winding. Taking advantage of this feature, the decorative sheet of the present invention can be suitably used as a decorative sheet for decorating an adherend such as a plastic having a curved surface.
Specifically, the decorative sheet with an adhesive layer having an adhesive layer on the back surface of the decorative sheet of the present invention can be applied to various interior and exterior parts for automobiles, interior and exterior parts of buildings, building materials, furniture, and home appliances. It can be applied to members.

  It does not specifically limit as an adhesive agent used for a decorative sheet with an adhesive bond layer, A heat sensitive adhesive, a pressure sensitive adhesive (adhesive), etc. are mentioned. Examples of the resin used for the adhesive include acrylic resins, vinyl chloride resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, styrene-acrylic copolymer resins, polyester resins, and polyamide resins. At least one resin selected from the group consisting of resins can be used. Further, a two-component curable polyurethane adhesive or a polyester adhesive using isocyanate as a curing agent can also be applied.

A decorative sheet with an adhesive layer is prepared by applying the above resin into a form that can be applied as a solution or emulsion, by means of a gravure printing method, a screen printing method or a reverse coating method using a gravure plate. It can form by apply | coating to (the back surface of a base material sheet), and drying as needed.
Although there is no restriction | limiting in particular in the thickness of an adhesive bond layer, Usually, it is the range of 1-100 micrometers. By setting it as this range, the adhesiveness of a to-be-adhered material and a decorative sheet can be improved more.

[Molding]
The molded article of the present invention has the mirror surface decorative sheet of the present invention on an adherend. Examples of such a molded product include a molded product having an adherend, an adhesive layer, and a decorative sheet of the present invention in order. The molded product is obtained, for example, by laminating an adhesive layer with an adhesive layer facing the back surface of the decorative sheet and an adhesive layer.
The shape and use of the molded product are not particularly limited, and can be applied to various members such as automobile interior and exterior parts, building interior and exterior, building materials, furniture, and home appliances.
The decorative sheet of the present invention is excellent in specularity, can be attached following a complicated shape and a shape having corners, and does not cause cracks or changes in appearance. Therefore, the molded product of the present invention is not limited to a flat plate shape, and may be a molded product having a curved surface shape stricter than 2R, for example.

Although it does not specifically limit as an adherend used for the molded article of this invention, For example, when a molded article is a vehicle interior / exterior component, a household appliance, etc., a plastic adherend is mentioned.
As the plastic adherend, those made of various synthetic resins can be used. Synthetic resins include polyolefin resins, vinyl resins, polyester resins, acrylic resins, polyamide resins, cellulose resins, polystyrene resins, polycarbonate resins, polyarylate resins, polyimide resins, ABS resins, urethane resins, epoxy resins, and the like. .

  Further, in order to improve the adhesion between the adherend and the decorative sheet, an oxidation method such as a corona discharge treatment, a chromium oxidation treatment, a flame treatment, a hot air treatment, an ozone-ultraviolet treatment method may be applied to one or both sides as desired. Alternatively, a physical or chemical surface treatment such as a concavo-convex method such as a sand blast method or a solvent treatment method can be performed.

  It does not specifically limit as an adhesive agent used for the adhesive layer agent for adhere | attaching an adherend and a decorative sheet, A heat sensitive adhesive, a pressure sensitive adhesive (adhesive) etc. are mentioned. Examples of the resin used for the adhesive constituting this adhesive layer include acrylic resins, vinyl chloride resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, styrene-acryl copolymer resins, At least one resin selected from polyester resins and polyamide resins is used. Further, a two-component curable polyurethane adhesive or a polyester adhesive using isocyanate as a curing agent can also be applied.

  The adhesive layer is a reverse coating using a gravure printing method, a screen printing method, or a gravure plate on the back surface of the decorative sheet or the back surface of the adherend, in which the above resin is made into a solution or emulsion form. It can be formed by coating and drying by means such as a method. In addition, when using a decorative sheet with an adhesive layer in which an adhesive layer is previously provided on the back surface of the decorative sheet as described above, it is not necessary to form an adhesive layer immediately before bonding to the adherend, and workability or production Good sex.

  Although there is no restriction | limiting in particular in the thickness of an adhesive bond layer, Usually, it is the range of 1-100 micrometers. By setting it as this range, the adhesiveness of a to-be-adhered material and a decorative sheet can be improved more.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
About the decorative sheet obtained in each example, the property or characteristic was evaluated with the following measuring method.

(1) Ten-point average roughness (Rz _JIS ) and arithmetic average roughness (Ra)
The surface roughness meter (manufactured by Tokyo Seimitsu Co., Ltd., Handy Surf E-35A) was measured by a method based on JIS B0601: 2001 under the conditions of a cutoff value of 0.8 mm and an evaluation length of 4 mm.

(2) L * value Using a spectrocolorimeter (manufactured by Konica Minolta, spectrocolorimeter CM-3700d), the L * value on the decorative sheet surface obtained in each example was measured.

(3) Crack generation elongation A strip-shaped test piece was cut out from the decorative sheet in accordance with JIS K7127: 1999, and the test piece was pulled at 23 ° C. ± 2 ° C. using a tensile tester at a tensile rate of 200 mm / min. The sample was pulled at an arbitrary elongation under the conditions of a distance between chucks of 100 mm and a width of 15 mm. Next, the space between the chucks of the test piece was colored with a whiteboard marker, the colored portion was wiped off with a cloth, and the elongation at the time when it became impossible to wipe off due to the occurrence of a crack was defined as the crack generation elongation.

(4) Specularity (20 ° gloss)
It measured by the method based on JISZ8741-1997 using the glossiness measuring device (BYG Gardner "micro gloss") on the conditions of an angle of 20 degrees. The measurement is carried out at any five locations on the surface protective layer for the sheet after producing the decorative sheet and immediately after being drawn out after being wound up as a roll and after 24 hours from the drawing, and the average value is taken as the measured value. did.

(5) Workability evaluation (visual appearance evaluation)
An adhesive (acrylic pressure sensitive adhesive, manufactured by Sanyo Kasei Kogyo Co., Ltd., Polysic 470-S) was applied at a thickness of 20 g / m ^{2 on} the back surface of the decorative sheet obtained in each example, and a curvature of 1.0 R was applied. The decorative sheet was affixed to a convex portion, and the appearance of the decorative sheet was visually observed under a fluorescent lamp (straight tube type), and evaluated according to the following criteria.
○: No change in appearance (no whitening or cracks observed)
Δ: slight whitening or cracking change in appearance, but no problem in actual use ×: significant change in appearance (whitening or cracking is observed)

(6) Evaluation of workability (trackability)
Similarly to the above (5), the following criteria evaluated the followability when an adhesive was applied to the back surface of the decorative sheet obtained in each example and applied to a convex portion having a curvature of 1.0R.
○: There is almost no peeling at the end (springback), and it can follow without any problem. Δ: Minor peeling is seen at the end and difficult to follow, but there is no problem in actual use. ×: Significant peeling occurs at the end. And cannot follow

Example 1
A colored polypropylene resin sheet (thickness: 100 μm, containing polypropylene-based thermoplastic elastomer) is prepared as a base sheet, and a two-component curable primer layer forming resin composition having the following composition is applied to one surface of the base sheet. A layer (thickness: 2 μm) is formed, and a two-component curable polyester-urethane resin composition (containing 65 parts by mass of silica as a matting agent with respect to 100 parts by mass of the resin component) is applied to the other side of the primer. A layer (thickness: 2 μm) was formed.
Next, an ionizing radiation curable resin composition having the following composition was applied on the primer layer by gravure printing at an application amount of 10 g / m ² to form a coating film. Next, the coating film was crosslinked and cured by irradiation with an electron beam under the conditions of 175 keV and 5 Mrad (50 kGy) to form a surface protective layer (thickness: 10 μm) to obtain a mirror-finished decorative sheet.
The obtained mirror surface decorative sheet was evaluated by the above method. The results are shown in Table 1.

(Primer layer forming resin composition)
Main agent: Polycarbonate urethane / acrylic copolymer 100 parts by mass Curing agent: 1,6-hexamethylene diisocyanate 5 parts by mass Matting agent (average particle size 4 μm) 15 parts by mass Ultraviolet absorber: 2- [4-{(2- Hydroxy-3-dodecyloxypropyl) oxy} -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine [Tinuvin 400 (trade name), BASF Japan Ltd. 5 parts by weight UV absorber: 2- (2-hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine [Tinuvin 479 (trade name), manufactured by BASF Japan Ltd.] 5 parts by weight Light stabilizer: bis (1-octyloxy-2,2,6,6-te Ramechiru 4-piperidyl) sebacate [Tinuvin 123 (trade name), manufactured by BASF Japan Ltd.] 1 part by weight

(Ionizing radiation curable resin composition for surface protective layer formation)
Ionizing radiation curable resin: urethane acrylate oligomer (functional group number: 2, weight average molecular weight: 3000) and urethane acrylate oligomer (functional group number: 2, weight average molecular weight: 4500) (mixing ratio (molar ratio) 4: 6) ) 100 parts by mass UV absorber: 2- (2-hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine [Tinuvin 479 (Trade name), manufactured by BASF Japan Ltd.] 2 parts by weight Light stabilizer having a reactive group: 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate [Sanol LS-3410 (trade name) , Manufactured by BASF Japan Ltd.] 4 parts by mass Reactive silicone compound: polyether-modified silicone [57ADDITI E (trade name), manufactured by Dow Corning Toray Co., Ltd.] 0.5 parts by weight

Examples 2-6 and Comparative Examples 1-3
In Example 1, except that the ten-point average roughness (Rz _JIS ) and arithmetic average roughness (Ra) of the back surface of the decorative sheet, the thickness of the surface protective layer, and the crack generation elongation were as shown in Table 1. A decorative sheet was obtained in the same manner as in Example 1.
The obtained mirror surface decorative sheet was evaluated by the above method. The results are shown in Table 1.

Comparative Example 4
In Example 1, a decorative sheet was obtained in the same manner as in Example 1 except that a colored polypropylene resin sheet (thickness: 100 μm, not containing a thermoplastic elastomer) was used as the base sheet.
The obtained decorative sheet was evaluated by the above method. The results are shown in Table 1.

  As shown in Table 1, the mirror surface decorative sheet of the present invention is excellent in both specularity and workability, and the gloss value is improved after 24 hours as compared with immediately after winding the sheet. This is considered that the unevenness on the back surface of the sheet is once formed on the surface protective layer and then recovered by the self-repairing function of the surface protective layer.

  ADVANTAGE OF THE INVENTION According to this invention, while having the outstanding bending workability, the dark-colored decorative sheet which has the favorable mirror surface property after winding of a sheet | seat, and a molded article which has this can be obtained.

DESCRIPTION OF SYMBOLS 1 Base material sheet 2 Surface protective layer 3 Primer layer 4 Back surface primer layer 5 Masking film 10 Mirror surface decorative sheet

Claims (6)

A mirror surface decorative sheet having a base sheet and a surface protective layer, wherein the base sheet is a polyolefin base sheet containing a thermoplastic elastomer, and the surface protective layer is a cured product of an ionizing radiation curable resin composition. The crack generation elongation measured by the following method of the surface protective layer is more than 20% and 100% or less, and the ten-point average roughness of the back surface of the mirror-finished decorative sheet measured according to JIS B0601: 2001 _{(Rz JIS)} is 3μm or more and 15μm or less, and, JIS Z8781-4: ^{L *} value in ^{the L} * ^a * ^{b *} color system defined in 2013 is 50 or less, the specular decorative sheet.
(Measurement of crack elongation)
A strip-shaped test piece according to JIS K7127: 1999 is prepared as a decorative sheet, and the test piece is used at 23 ° C. ± 2 ° C. under the conditions of a tensile speed of 200 mm / min and a chuck distance of 100 mm. After pulling at an arbitrary elongation, the inside of the chuck is colored with a whiteboard marker, and the colored portion is wiped off with a cloth. It was.   The mirror surface decorative sheet according to claim 1, wherein the 20 ° gloss of the surface protective layer surface of the mirror surface decorative sheet measured according to JIS Z8741-1997 is 40% or more.   The mirror surface decorative sheet according to claim 1 or 2, wherein the surface protective layer has a thickness of 6 to 20 µm.   The mirror surface decorative sheet according to any one of claims 1 to 3, wherein the base sheet is a colored base sheet.   The mirror surface decorative sheet with an adhesive layer which has an adhesive layer in the back surface of the mirror surface decorative sheet of any one of Claims 1-4.   The molded article which has a mirror surface decorative sheet of any one of Claims 1-4 on a to-be-adhered material.