JP7183583B2 - protective films and sheets - Google Patents

Description

TECHNICAL FIELD The present invention relates to a protective film and a sheet using the same.

Conventionally, general printed matter does not have high resistance to ultraviolet light, water, and the like. Therefore, in applications such as outdoor decorative sheets and posters that require resistance to these (weather resistance), a protective film is provided on the surface layer for the purpose of protecting printed matter.
Some protective films have a surface protective layer, and the surface protective layer may be a transparent hard coat layer provided to impart scratch resistance and abrasion resistance to the protective film. Additives such as ultraviolet absorbers are sometimes added to the surface protective layer to impart weather resistance. For example, hydroxyphenyltriazine compounds have been proposed as UV absorbers that impart excellent weather resistance (Patent Documents 1 and 2). However, when a hydroxyphenyltriazine-based UV absorber is applied to a surface protective layer, not only does the weather resistance differ depending on the structure of the UV absorber, but white turbidity may occur, resulting in a reduction in the design of the printed matter.

U.S. Patent Application Publication No. 2004/0241111 U.S. Pat. No. 6,191,199

SUMMARY OF THE INVENTION An object of the present invention is to provide a protective film including a surface protective layer that has excellent weather resistance and little white turbidity that impairs the design, and a sheet using the same.

As a result of intensive studies, the present inventors have found that, in a protective film comprising a surface protective layer and a transparent resin layer, a protective film containing an ultraviolet absorber comprising a hydroxyphenyltriazine compound having a specific structure in the surface protective layer and a protective film containing the same The inventors have found that the sheet used achieves the above-mentioned objectives, and have arrived at the present invention.
One aspect of the present invention for solving the above problems is a protective film including at least a surface protective layer and a transparent resin layer formed under the surface protective layer, wherein the surface protective layer is the following general A protective film characterized by containing a hydroxyphenyltriazine-based ultraviolet absorber having a structure represented by formula (1).

(In the general formula (1), R1 to R3 each independently represent a hydrogen atom, a methyl group, a phenyl group, or an alkoxy group, and at least two of them are alkoxy groups having 8 to 18 carbon atoms and not containing a carbonyl group, R4 and R5 each independently represent a hydroxyl group, a methyl group, or a hydrogen atom, and R6 to R8 each independently represent a methyl group or a hydrogen atom.)

According to one aspect of the present invention, there are provided a protective film including a surface protective layer that has excellent weather resistance and little white turbidity that impairs design, and a sheet using the same.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the cross section of the protective film which concerns on 1st embodiment of this invention. FIG. 4 is a schematic diagram showing a cross section of a decorative sheet according to a second embodiment of the present invention;

[First embodiment]
As a first embodiment of the present invention, the structure of a protective film 10 having a transparent resin layer 11 and a surface protective layer 12 will be described with reference to FIG. However, in each drawing described below, the same reference numerals are given to the parts that correspond to each other, and the description of overlapping parts will be omitted as appropriate. Further, the present embodiment exemplifies the configuration for embodying the technical idea of the present invention, and does not specify the material, shape, structure, arrangement, dimensions, etc. of each part as follows. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

(Surface protective layer)
The protective film 10 according to this embodiment includes a transparent resin layer 11 and a surface protective layer 12 formed on one side of the transparent resin layer 11 , that is, on the upper layer of the transparent resin layer 11 .
The surface protective layer 12 according to the present embodiment is a layer provided to provide the protective film 10 with, for example, weather resistance, scratch resistance, stain resistance, and designability. is applied to the transparent resin layer 11 and then cured.

As the curable resin material, for example, a thermosetting resin containing a hydroxyl group or an epoxy group as a curing site, an ionizing radiation curable resin containing an unsaturated double bond, or the like can be used. Resins are preferred. Ultraviolet rays and electron beams are mainly used for ionizing radiation curing. UV curing is sometimes disadvantageous in terms of weather resistance because UV absorbers that are usually blended in the surface protective layer 12 inhibit curing and limit the types of UV absorbers that can be used. Further, in electron beam curing, the electron beam has high permeability and damages the underlying transparent resin layer, which may adversely affect the weather resistance.

As the thermosetting resin according to the present embodiment, a two-liquid curing polyurethane resin is particularly preferable from the viewpoint of curing temperature. That is, the surface protective layer 12 according to this embodiment is preferably made of a two-liquid curing polyurethane resin. A two-liquid curing polyurethane resin is, for example, a resin that is cured by forming a urethane bond between a polyol and a polyisocyanate. Examples of polyols that can be used include acrylic polyols, polyester polyols, and polycarbonate polyols. Examples of polyisocyanate that can be used include hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylene diisocyanate, diphenylmethane diisocyanate, and hydrogenated diphenylmethane diisocyanate.

The surface protective layer 12 may contain a hydroxyphenyltriazine-based ultraviolet absorber having a structure represented by the following general formula (1), and an ultraviolet absorber having a structure represented by the following general formula (2). It is more preferable if it contains 2,4-bis[2-hydroxy-4-(2-ethylhexyloxy)phenyl)]-6-(4-methoxyphenyl)-s-, especially represented by the following formula (3) triazines are preferred.

In general formula (1), R1 to R3 each independently represent a hydrogen atom, a methyl group, a phenyl group, or an alkoxy group, and at least two of them are alkoxy groups having 8 to 18 carbon atoms and not containing a carbonyl group. , R4 and R5 each independently represent a hydroxyl group, a methyl group or a hydrogen atom, and R6 to R8 each independently represent a methyl group or a hydrogen atom.

In general formula (2), R1 and R2 are alkoxy groups having 8 to 18 carbon atoms, R3 is an alkoxy group having 1 to 4 carbon atoms, R4 is a hydroxyl group, and R5 to R8 are hydrogen atoms.

The amount of the hydroxyphenyltriazine-based ultraviolet absorber to be blended is not particularly limited, and is appropriately set depending on various conditions such as the thickness of the surface protective layer 12 and the adhesive layer 20 and the substrate 30 described later. It is within the range of 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the resin forming the protective layer 12 . If the blending amount of the hydroxyphenyltriazine-based ultraviolet absorber is less than 1 part by mass, it may not be possible to impart sufficient weather resistance to the protective film 10 . Moreover, if the amount of the hydroxyphenyltriazine-based ultraviolet absorber exceeds 20 parts by mass, problems such as a decrease in the strength of the surface protective layer 12 and bleeding of the ultraviolet absorber increase.

The surface protective layer 12 may optionally contain, for example, UV absorbers other than the aforementioned hydroxyphenyltriazine-based UV absorbers, heat stabilizers, light stabilizers, antiblocking agents, catalyst scavengers, colorants, Various additives such as light scattering agents and luster modifiers may be added.
Examples of other UV absorbers include 2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-n-octyloxyphenyl)-s-triazine, 2,4,6- tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-s-triazine, 2-[2-hydroxy-4-(2-ethylhexyloxy)phenyl]-4,6-dibiphenyl-s-triazine, Hydroxyphenyl triazine compounds such as 2-[[2-hydroxy-4-[1-(2-ethylhexyloxycarbonyl)ethyloxy]phenyl]]-4,6-diphenyl-s-triazine, 2-(5-chloro-2H -benzotriazole-2-yl)-6-tert-butyl-4-methylphenol, 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol. An ultraviolet absorber is mentioned.

Examples of light stabilizers include 2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2′-n-butylmalonate bis(1,2,2,6,6-pentamethyl-4 -piperidyl), bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4- Hindered amine light stabilizers such as butane tetracarboxylate are included.
The method of forming the surface protective layer 12 is not particularly limited, and the above-mentioned material is applied as a coating liquid by a conventional method such as gravure coating, micro gravure coating, comma coating, knife coating, and die coating. After that, the surface protective layer 12 may be formed by curing by a method suitable for the material, such as heat curing or ultraviolet curing.
Note that the surface protective layer 12 may be provided after the transparent resin layer 11 is bonded to the base material 30 described below.

(Transparent resin layer)
The material for forming the transparent resin layer 11 according to this embodiment is not particularly limited as long as it has the necessary transparency. Polyester resins such as talat, acrylic resins such as polymethyl methacrylate, cycloolefin resins, polycarbonate resins, polyvinyl chloride resins, polyvinylidene fluoride, fluororesins such as ethylenetetrafluoroethylene copolymer, etc., may be appropriately selected and used. can be done.

The transparent resin layer 11 may contain additives such as ultraviolet absorbers, heat stabilizers, and light stabilizers, if necessary. As the ultraviolet absorber and light stabilizer, for example, those applied to the surface protective layer 12 described above can be used.
The transparent resin layer 11 is produced by, for example, a normal method such as calender film formation or extrusion film formation, and may be provided with surface irregularities in order to impart design properties. Examples of the method of providing unevenness include a method of performing hot embossing after extrusion molding, and a method of performing embossing simultaneously with extrusion molding using a cooling roll provided with unevenness during extrusion molding.

[Second embodiment]
As a second embodiment of the present invention, a configuration in which the protective film 10 according to the first embodiment and the base material 30 are joined to form a decorative sheet 40 will be described with reference to FIG.
The decorative sheet 40 is constructed by bonding the protective film 10 including the surface protective layer 12 and the transparent resin layer 11, that is, the protective film 10 according to the first embodiment, to the substrate 30 via the adhesive layer 20. . Note that FIG. 2 shows a decorative sheet 40 in which the transparent resin layer 11 provided on the protective film 10 and the pattern layer 32 provided on the base material 30 to be described later are bonded via the adhesive layer 20 .

(Original fabric)
The base material 30 includes a raw fabric 31 and a pattern layer 32 provided on one side of the raw fabric 31 .
Examples of raw material 31 include paper such as thin paper, titanium paper, and resin-impregnated paper, synthetic resin such as polyethylene, polypropylene, polybutylene, polystyrene, polycarbonate, polyester, polyamide, ethylene-vinyl acetate copolymer, polyvinyl alcohol, and acrylic. , or foams of these synthetic resins, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, styrene-butadiene copolymer rubber, styrene-isoprene-styrene block copolymer rubber, styrene-butadiene-styrene block copolymer It can be arbitrarily selected from rubber such as rubber and polyurethane, organic or inorganic non-woven fabric, synthetic paper, metal foil such as aluminum, iron, gold and silver.
The original fabric 31 may be provided with, for example, a primer layer (not shown) on one or both sides of the original fabric 31 in order to supplement the adhesion with the layers adjacent to the original fabric 31, or may be subjected to corona treatment, plasma treatment, Surface treatments such as ozone treatment, electron beam treatment, ultraviolet treatment, and dichromic acid treatment may be applied.

(picture layer)
The pattern layer 32 is, for example, a pattern printed on the raw fabric 31 using ink. The ink used to form the pattern layer 32 may contain a binder, and examples of the binder include nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, and polyester. It can be used singly or appropriately selected from among modified products. Further, they may be water-based, solvent-based, or emulsion-type, and may be one-liquid type or two-liquid type using a curing agent.
As a method of curing the ink used for forming the pattern layer 32, there is a method of curing the ink by irradiation with ultraviolet rays, electron beams, or the like. Among them, the most common method is to use urethane-based ink and cure it with isocyanate.

In addition to these binders, the ink used to form the pattern layer 32 contains various additives such as pigments, dyes, and other coloring agents, extender pigments, solvents, light stabilizers, and the like, which are contained in ordinary inks. It is Examples of highly versatile pigments include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and pearl pigments such as mica.
The method of providing the pattern layer 32 is not particularly limited, and ordinary printing methods such as gravure printing, offset printing, screen printing, flexographic printing, and ink jet printing can be used.

The method of bonding the protective film 10 to the substrate 30 is not particularly limited, and various lamination methods such as heat lamination, extrusion lamination, dry lamination, and sand lamination are used as necessary, for example, via the adhesive layer 20. be able to.
The adhesive layer 20 is not particularly limited. For example, a material that is appropriately selected from resin materials such as urethane, acrylic, acrylic silicon, fluorine, and epoxy and is made into an ink is coated with, for example, gravure coat or micro gravure. It is formed using a usual coating method such as coating, comma coating, knife coating, die coating, and the like.
Regarding the thickness of each layer constituting the decorative sheet 40 according to the present embodiment, the original sheet 31 is 20 μm to 150 μm, the adhesive layer 20 is 0.2 μm to 20 μm, and the transparent resin layer 11 is It is desirable that the thickness of the surface protective layer 12 is 20 μm to 200 μm, and that the surface protective layer 12 is 3 μm to 20 μm. Also, the total thickness of the decorative sheet 40 is preferably within the range of 45 μm to 250 μm.

EXAMPLES The present invention will now be described in detail with reference to examples and comparative examples.
<Example 1>
Obtained by providing a pattern layer (thickness 3 μm) by gravure printing a wood grain pattern on a polyethylene raw fabric (thickness 70 μm) with concealability using two-liquid urethane ink (V180; manufactured by Toyo Ink Co., Ltd.). A transparent resin layer composition shown below was extrusion-laminated to a thickness of 80 μm on the obtained base material through an adhesive for dry lamination (Takelac A540; manufactured by Mitsui Chemicals, Inc.) (thickness: 2 μm). Further, the following surface protective layer composition was coated on the transparent resin layer by gravure coating and dried, and then cured at 25° C. for 3 days to obtain a decorative sheet of Example 1.

(Transparent resin layer composition)
・Transparent homopolypropylene resin (Prime PP; manufactured by Prime Polymer Co., Ltd.)
. . 99 parts by mass Ultraviolet absorber (TINUVIN 326; manufactured by BASF Japan Ltd.)
... 0.5 parts by mass Light stabilizer (tinuvin XT55; manufactured by BASF Japan Ltd.)
・・・ 0.5 part by mass

(Surface protective layer composition)
・ Main agent (methyl methacrylate / 2 hydroxyethyl methacrylate = 95/5 copolymer) ... 90 parts by mass ・ Ultraviolet absorber (Tinosorb S (formula (3) below); manufactured by BASF Japan Co., Ltd.)
... 9 parts by mass Light stabilizer (tinuvin 123; manufactured by BASF Japan Co., Ltd.)
... 1 part by mass Curing agent (Takenate D170; Mitsui Chemicals, Inc.) ... 10 parts by mass Solvent (ethyl acetate) ... 240 parts by mass

<Comparative Example 1>
Comparative Example 1 was prepared in the same manner as in Example 1 except that the UV absorber of the surface protective layer composition of Example 1 was a compound represented by the following formula (4) (ADEKA STAB LA-F70; manufactured by ADEKA Corporation). I got a cosmetic sheet.
<Comparative Example 2>
The cosmetic of Comparative Example 2 was prepared in the same manner as in Example 1 except that the ultraviolet absorber of the surface protective layer composition of Example 1 was a compound represented by the following formula (5) (TINUVIN 400; manufactured by BASF Japan Co., Ltd.). got a sheet.

<Comparative Example 3>
The cosmetic of Comparative Example 3 was prepared in the same manner as in Example 1 except that the ultraviolet absorber of the surface protective layer composition of Example 1 was a compound represented by the following formula (6) (TINUVIN 477; manufactured by BASF Japan Co., Ltd.). got a sheet.
<Comparative Example 4>
The cosmetic of Comparative Example 4 was prepared in the same manner as in Example 1 except that the ultraviolet absorber of the surface protective layer composition of Example 1 was a compound represented by the following formula (7) (TINUVIN 479; manufactured by BASF Japan Ltd.). got a sheet.

The hydroxyphenyltriazine-based UV absorber used in each example and comparative example has a structure in which R1 to R8 in the following general formula (8) are the substituents shown in Table 1 below. It corresponds to the hydroxyphenyltriazine-based ultraviolet absorber represented by the general formula (1) defined in the embodiments.

＜評価＞
上記実施例および比較例で得られた化粧シートについて、以下の方法で意匠性と耐候性を評価した。評価結果を下記表２に示す。

<Evaluation>
The decorative sheets obtained in the above examples and comparative examples were evaluated for design and weather resistance by the following methods. The evaluation results are shown in Table 2 below.

a) Designability The appearance of the decorative sheet was visually evaluated according to the following criteria. However, the reference sheet was prepared separately from a sheet containing no ultraviolet absorber in Example 1.
○: No difference in appearance from the reference sheet.
x: A feeling of whiteness is recognized as compared with the reference sheet.

b) Weather resistance The appearance of the decorative sheet after the accelerated weather resistance test was visually observed and evaluated as 4, 3, 2, and 1 in descending order of discoloration of the pattern. The accelerated weather resistance test uses an eye super UV tester (SUV-W161; Iwasaki Electric Co., Ltd.), with a black panel temperature of 63 ° C and an illumination of 65 mW / cm ² , (20 hours of UV irradiation + 4 hours of condensation) as one cycle. 30 cycles were performed. If the weather resistance evaluation is "1" or "2", there is no problem in use, so it was judged as acceptable.

As shown in Table 2, the decorative sheet according to the present embodiment exemplified in Example 1 has less cloudiness and good design by applying a hydroxyphenyltriazine-based ultraviolet absorber having a specific structure to the surface protective layer. and excellent weather resistance.

INDUSTRIAL APPLICABILITY The present invention can be used not only for outdoor sheets such as decorative sheets, posters and signs, but also for indoor sheets such as surface materials for fittings and flooring materials.

10 Protective film 11 Transparent resin layer 12 Surface protective layer 20 Adhesive layer 30 Base material 31 Original fabric 32 Pattern layer 40 Decorative sheet

Claims (8)

A protective film including at least a surface protective layer and a transparent resin layer formed under the surface protective layer,
The surface protective layer contains a hydroxyphenyltriazine-based ultraviolet absorber having a structure represented by the following general formula (1) and is formed of a two-liquid curing polyurethane resin,
A protective film, wherein the polyurethane resin is a copolymer of methyl methacrylate and 2-hydroxyethyl methacrylate .

(In the general formula (1), R1 to R3 each independently represent a hydrogen atom, a methyl group, a phenyl group, or an alkoxy group, and at least two of them are alkoxy groups having 8 to 18 carbon atoms and not containing a carbonyl group, R4 and R5 each independently represent a hydroxyl group, a methyl group, or a hydrogen atom, and R6 to R8 each independently represent a methyl group or a hydrogen atom.) A protective film including at least a surface protective layer and a transparent resin layer formed under the surface protective layer,
The surface protective layer contains a hydroxyphenyltriazine-based ultraviolet absorber having a structure represented by the following general formula (1) and is formed of a two-liquid curing polyurethane resin,
The polyurethane resin is an acrylic urethane resin, a polyester urethane resin, or a polycarbonate urethane resin,
A protective film , wherein the transparent resin layer contains a benzotriazole-based ultraviolet absorber .

(In the general formula (1), R1 to R3 each independently represent a hydrogen atom, a methyl group, a phenyl group, or an alkoxy group, and at least two of them are alkoxy groups having 8 to 18 carbon atoms and not containing a carbonyl group, R4 and R5 each independently represent a hydroxyl group, a methyl group, or a hydrogen atom, and R6 to R8 each independently represent a methyl group or a hydrogen atom.) A protective film including at least a surface protective layer and a transparent resin layer formed under the surface protective layer,
The surface protective layer contains a hydroxyphenyltriazine-based ultraviolet absorber having a structure represented by the following general formula (1) and is formed of a two-liquid curing polyurethane resin,
The polyurethane resin is an acrylic urethane resin, a polyester urethane resin, or a polycarbonate urethane resin,
A protective film , wherein the transparent resin layer contains an ultraviolet absorber having a structure represented by the following formula (4) .

(In the general formula (1), R1 to R3 each independently represent a hydrogen atom, a methyl group, a phenyl group, or an alkoxy group, and at least two of them are alkoxy groups having 8 to 18 carbon atoms and not containing a carbonyl group, R4 and R5 each independently represent a hydroxyl group, a methyl group, or a hydrogen atom, and R6 to R8 each independently represent a methyl group or a hydrogen atom.)

4. The protective film according to any one of claims 1 to 3, wherein the hydroxyphenyltriazine-based ultraviolet absorber has a structure represented by the following general formula (2).

(In general formula (2), R1 and R2 are alkoxy groups having 8 to 18 carbon atoms, R3 is an alkoxy group having 1 to 4 carbon atoms, R4 is a hydroxyl group, and R5 to R8 are hydrogen atoms.) 4. The protective film according to any one of claims 1 to 3, wherein the hydroxyphenyltriazine-based ultraviolet absorber has a structure represented by the following formula (3).

6. The protective film according to any one of claims 1 to 5 , wherein the transparent resin layer is made of polyester resin, acrylic resin, polyvinyl chloride resin, or fluororesin. 6. The protective film according to any one of claims 1 to 5 , wherein the transparent resin layer is made of polyvinylidene fluoride or an ethylenetetrafluoroethylene copolymer. A structure in which the protective film according to any one of claims 1 to 7 and a substrate are bonded with an adhesive layer ,
A sheet , wherein the substrate comprises a raw fabric and a pattern layer located on the side of the adhesive layer .

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