JP2022151481A - Resin sheet and decorative sheet - Google Patents

Abstract

To provide a resin sheet which is excellent in flame retardancy and prevention of fire spread, and suppresses flexural whitening.SOLUTION: A resin sheet has a transparent resin layer on at least a base material sheet, where (1) the transparent resin layer contains a phosphinic acid metal salt-based flame retardant, (2) the base material sheet contains magnesium hydroxide, and (3) the transparent resin layer and the base material sheet contains at least one selected from the group consisting of a polyolefin-based resin and a polyester-based resin.SELECTED DRAWING: None

Description

The present invention relates to a resin sheet and a decorative board.

2. Description of the Related Art Conventionally, resin sheets are laminated on the surfaces of various articles in order to impart design properties. For example, a resin sheet is laminated on a base material and used as a decorative board used for the floor surface of a building.

Since such veneers are laminated on the surface of buildings, there are cases where they are required to meet the requirements for noncombustible certification, which indicates that they are difficult to burn in the event of a fire. be. Here, the requirements for obtaining noncombustible certification are the total calorific value, maximum heat generation rate, crack and It is a given requirement for the occurrence of holes.

As a resin sheet used for a decorative board that satisfies the above requirements, a base sheet, a transparent resin layer and a surface protective layer are laminated in order, the thickness of each layer is within a specific range, and a flame retardant is contained. There has been proposed a decorative sheet that does this (see, for example, Patent Literature 1).

The above-mentioned decorative sheet is also a resin sheet with excellent flame resistance and can be used without any problems. Although it is an important performance in terms of the fire, there is room for further improvement in terms of the difficulty of spreading fire. Therefore, in addition to the flame retardancy according to ISO 5660-1, it is important for the resin sheet to suppress the expansion of the area of the burning resin sheet in the event of a fire, and to prevent the fire from spreading.

Depending on the configuration of the decorative sheet, it is difficult to achieve both the flame retardancy and the difficulty of spreading fire. For example, in an exothermic test using a cone calorimeter for evaluating flame retardancy, it is effective to reduce the amount of heat generated by thinning the resin sheet to reduce the organic mass in the product. However, thinning the decorative sheet is not necessarily effective in the horizontal burning test for evaluating the difficulty of spreading fire.

Flame retardants are also useful for imparting flame retardancy to the decorative sheet. Such flame retardants include halogen flame retardants, antimony flame retardants, metal hydroxide flame retardants, phosphate ester flame retardants Flame retardants and the like are used. However, halogen-based flame retardants and antimony-based flame retardants are unfavorable from the environmental point of view.

When a metal hydroxide-based flame retardant is used as the flame retardant, it must be added in a large amount. In addition, the phosphate ester-based flame retardant forms combustion char during combustion to suppress combustion. Even when the phosphate ester flame retardant is used, it must be added in a large amount in order to form burning char and obtain a flame retardant effect. Since these flame retardants have a large particle size, when they are used on a printing sheet, they become foreign matter on the surface of the printing sheet, which easily causes print defects. Moreover, when these flame retardants are used in the decorative sheet, the transparency of the decorative sheet may be impaired and the sheet may be colored, which limits the layers that can be used. For this reason, it is necessary to use an appropriate flame retardant in an appropriate layer structure in the resin sheet.

Furthermore, the resin sheet may be laminated on an adherend and used as a decorative board. In this case, when the decorative plate is bent and processed, the resin sheet is also bent accordingly. In this case, depending on the selection of the flame retardant in the resin sheet and the composition of the resin forming the layer of the resin sheet, there is a problem that the bent portion of the resin sheet may be bent and whitened.

Therefore, there is a demand for the development of a resin sheet that is excellent in flame retardancy and resistance to the spread of fire, and in which whitening due to bending is suppressed.

JP 2015-182379 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin sheet which is excellent in flame retardancy and resistance to the spread of fire, and in which whitening due to bending is suppressed.

As a result of extensive research, the present inventors have found that, in a resin sheet having at least a transparent resin layer on a base sheet, the transparent resin layer contains a metal phosphinate flame retardant and the base sheet contains water. The object is achieved by providing a resin sheet containing magnesium oxide, a transparent resin layer, and a resin sheet in which the base sheet contains at least one selected from the group consisting of polyolefin-based resins and polyester-based resins. We have found that it can be achieved, and have completed the present invention.

That is, the present invention relates to the following resin sheet and decorative board.
1. A resin sheet having a transparent resin layer on at least a base sheet,
(1) The transparent resin layer contains a metal phosphinate flame retardant,
(2) the base sheet contains magnesium hydroxide,
(3) The transparent resin layer and the base sheet contain at least one resin selected from the group consisting of polyolefin-based resins and polyester-based resins.
A resin sheet characterized by:
2. Item 2. The resin sheet according to Item 1, wherein the content of the magnesium hydroxide in the base sheet is 10% by mass or more.
3. Item 3. The resin sheet according to Item 1 or 2, wherein the metal phosphinate flame retardant is an aluminum phosphinate flame retardant.
4. Item 4. The resin sheet according to any one of items 1 to 3, wherein the content of the metal phosphinate flame retardant in the transparent resin layer is 5% by mass or more.
5. Item 5. The resin sheet according to any one of Items 1 to 4, wherein the transparent resin layer contains a polyolefin resin, and the polyolefin resin is an olefin thermoplastic elastomer.
6. Item 6. The resin sheet according to any one of Items 1 to 5, comprising at least a picture pattern layer and the transparent resin layer in this order on the base sheet.
7. Item 7. The resin sheet according to any one of Items 1 to 6, which has a surface protective layer on the side of the transparent resin layer opposite to the base sheet.
8. Item 8. The resin sheet according to Item 7, wherein the surface protective layer is an ionizing radiation-curable resin layer.
9. Item 9. The resin sheet according to any one of Items 1 to 8, wherein the side of the transparent resin layer opposite to the base sheet has an uneven shape.
10. A decorative board having the resin sheet according to any one of Items 1 to 9 on a substrate.

The resin sheet of the present invention is excellent in flame retardancy and flame spread resistance, and suppresses bending whitening.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the layer structure of the resin sheet of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of the layer structure of a base material (adherend) that constitutes the decorative board of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the layer structure of the decorative board of this invention. It is a schematic diagram which shows the test method of the difficulty of a fire spreading. It is a schematic diagram which shows the test method of the difficulty of a fire spreading. It is a schematic diagram which shows the test method of bending whitening.

Hereinafter, the resin sheet and decorative board of the present invention will be described in detail. In the resin sheet of the present invention, the side opposite to the side on which the base material of the resin sheet is laminated is the so-called "front side", which is the side that is visible when applied to a floor or the like. . Therefore, in this specification, the direction of the surface of the resin sheet opposite to the base material and the laminated side is referred to as "upper", and the opposite side, that is, the direction of the surface of the base material and the laminated side is referred to as "upper". Called "back" or "bottom". Similarly, in this specification, the direction of the resin sheet side of the decorative board is referred to as "upper", and the opposite side, that is, the direction of the substrate side is referred to as "back" or "lower".

1. Resin Sheet The resin sheet of the present invention is a resin sheet having a transparent resin layer on at least a base sheet, comprising: (1) the transparent resin layer containing a metal phosphinate flame retardant; ) The base sheet contains magnesium hydroxide, and (3) The transparent resin layer and the base sheet contain at least one selected from the group consisting of polyolefin-based resins and polyester-based resins. characterized by The resin sheet of the present invention having the characteristics described above has flame retardancy and fire resistance by providing the configurations (1) and (2) in the layer configuration having at least the transparent resin layer on the base sheet. Excellent in both flame spread resistance. Further, the resin sheet of the present invention further includes the configuration (3), so that the resin contained in the transparent resin layer and the flame retardant contained in the transparent resin layer have excellent affinity, and whitening due to bending is prevented. suppressed.

The resin sheet of the present invention has at least a transparent resin layer on the base sheet, and the layer structure is not limited as long as the above requirements (1) to (3) are satisfied. An example of the layer structure of the resin sheet of the present invention is a layer structure having at least a pattern layer and a transparent resin layer in this order on a substrate sheet. Further, as shown in FIG. 1, a substrate sheet 12, a picture pattern layer 13 (solid ink layer and/or pattern ink layer), an adhesive layer (not shown), a transparent resin layer 14, and a surface protective layer 15 are provided. It may have a layer structure in order (doubled resin sheet). Moreover, although not shown, the resin sheet of the present invention may have a synthetic resin backer layer on the opposite side of the base sheet to the transparent resin layer. Hereinafter, a resin sheet having such a layer structure will be specifically described as a typical example.

(base material sheet)
In the resin sheet of the present invention, the base sheet contains magnesium hydroxide.

Magnesium hydroxide is not particularly limited, and a particulate one can be used. The shape of the magnesium hydroxide particles is not particularly limited, and may be spherical, flake-like, needle-like, etc., and spherical particles are preferably used.

Magnesium hydroxide may be surface-treated with a fatty acid, a silane coupling agent, or the like in order to further improve affinity with the resin contained in the base sheet. Among these, those surface-treated with fatty acids are preferable.

A commercial item can be used as magnesium hydroxide. Commercial products of magnesium hydroxide include, for example, Magzees N, Magzees S, Magzees EP, Magzees W, etc. (manufactured by Kajima Chemical Co., Ltd.), ECOMAG, etc. (manufactured by Tateho Chemical Industry Co., Ltd.), Kisuma 5, Kisma 8, etc. ( Kyowa Kagaku Kogyo Co., Ltd.) can be used, and among these, Magseize N (Magsease N-6) (trade name, Kojima Kagaku Kogyo Co., Ltd.) can be preferably used.

The average particle size of magnesium hydroxide is preferably 0.1 to 5 μm, more preferably 0.1 to 1 μm. When the lower limit of the average particle size is within the above range, the dispersibility in the substrate sheet is improved, and the flame retardancy is further improved. When the lower limit is exceeded, the kneading torque increases during kneading with the resin, and aggregation tends to occur, resulting in a decrease in dispersibility. Further, when the upper limit of the average particle size is within the above range, the surface property of the resin sheet is improved, and the design quality such as the printed pattern formed on the surface of the resin sheet is further improved. If the upper limit is exceeded, particles and agglomerates derived from the particles tend to form on the surface of the sheet, and design quality tends to deteriorate.

The content of magnesium hydroxide in the base sheet is preferably 10% by mass or more, more preferably 15% by mass or more, based on 100% by mass of the base sheet. The content of magnesium hydroxide in the base sheet is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on 100% by mass of the base sheet. When the lower limit of the content of magnesium hydroxide is within the above range, the flame retardancy of the resin sheet is further improved. Moreover, since the upper limit of the content of magnesium is within the above range, the stability (thickness, width, etc.) of the resin sheet can be ensured during film formation.

The base sheet contains at least one resin selected from the group consisting of polyolefin resins and polyester resins.

As the polyolefin-based resin, a polyolefin-based thermoplastic resin is preferable, and an olefin-based thermoplastic elastomer is more preferable in that whitening caused by bending of the resin sheet is further suppressed.

More specifically, polyolefin resins include polyethylene, ethylene-α-olefin copolymer, polypropylene, polymethylpentene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, and ethylene-vinyl acetate copolymer. , ethylene-vinyl acetate copolymer saponified products, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, and the like. Among these, polypropylene is preferred.

Polyester-based thermoplastic resins can be used as polyester-based resins, and polyethylene terephthalate, polyalkylene terephthalate with high heat resistance [for example, polyethylene obtained by substituting a portion of ethylene glycol with 1,4-cyclohexanedimethanol, diethylene glycol, etc. terephthalate, so-called PET-G (manufactured by Eastman Chemical Company)], polybutylene terephthalate, polyethylene naphthalate, polyethylene naphthalate-isophthalate copolymer, and the like. Among these, polyalkylene terephthalate having high heat resistance is preferable.

The thickness of the base sheet is preferably 20-300 μm, more preferably 40-200 μm. The base sheet may be colored if necessary. In addition, the surface may be subjected to surface treatment such as corona discharge treatment, plasma treatment, ozone treatment, etc., or may be coated with a primer that is a base paint for enhancing adhesion to adjacent layers.

(Pattern layer)
The picture pattern layer is composed of a pattern ink layer and/or a solid ink layer. The pattern layer can be formed by known printing methods such as gravure printing, offset printing, silk screen printing, and inkjet printing. The pattern of the pattern ink layer includes, for example, a wood grain pattern, a stone grain pattern, a texture pattern, a leather pattern, a geometric pattern, letters, symbols, line drawings, various abstract patterns, flower patterns, landscapes, and characters. The solid ink layer is obtained by solid printing with colored ink. The picture pattern layer is composed of one or both of a pattern ink layer and a solid ink layer.

Inks used for the pattern layer include vehicles such as chlorinated polyolefins such as chlorinated polyethylene and chlorinated polypropylene, polyesters, polyurethanes composed of isocyanate and polyol, polyacrylics, polyvinyl acetates, polyvinyl chlorides, and vinyl chloride-vinyl acetates. One or a mixture of two or more of copolymers, cellulose-based resins, polyamide-based resins, etc. may be used, and pigments, solvents, various auxiliary agents, etc. may be added thereto to form inks. Among these, one or a mixture of two or more of polyesters, polyurethanes composed of isocyanates and polyols, polyacrylics, polyamide resins, and the like is preferable from the viewpoints of environmental concerns, adhesion to the surface to be printed, and the like.

The thickness of the pattern layer is not particularly limited, and can be appropriately set according to product characteristics, but the layer thickness is about 0.1 to 10 μm.

(Transparent adhesive layer)
A transparent adhesive layer is provided between the pattern layer and the transparent resin layer, if necessary. The transparent adhesive layer can be obtained, for example, by applying and drying a known adhesive for dry lamination such as a two-pack curable urethane resin.

The thickness of the transparent adhesive layer after drying is preferably about 0.1 to 30 μm, more preferably about 1 to 5 μm.

(Transparent resin layer)
In the resin sheet of the present invention, the transparent resin layer contains a metal phosphinate flame retardant.

で表される化合物が挙げられる。 Metal phosphinate flame retardants include metal phosphinate and/or metal diphosphinate (hereinafter also referred to as “metal phosphinate”).
Examples of metal phosphinic acid salts include the following general formula (1):

The compound represented by is mentioned.

で表される化合物が挙げられる。 As the diphosphinate metal salt, for example, the following general formula (2):

The compound represented by is mentioned.

In general formulas (1) and (2), R ¹ , R ² , R ³ and R ⁴ are each independently an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, and It is selected from the group consisting of 7-20 arylalkyl groups. R ⁵ is selected from the group consisting of an alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylarylene group having 7 to 20 carbon atoms, and an arylalkylene group having 7 to 20 carbon atoms. M is at least one metal selected from the group consisting of calcium (ion), magnesium (ion), aluminum (ion) and zinc (ion), m is 2 or 3, n is 1 or 3, x is 1 or 2;

For example, in the above general formula (1), when m is 2, the metal phosphinate includes compounds represented by the following general formula (1-1).

Further, for example, in the above general formula (1), when m is 3, examples of the metal phosphinate include compounds represented by the following general formula (1-2).

Further, for example, when m is 2, n is 1, and x is 1 in the above general formula (2), the diphosphinate metal salt includes a compound represented by the following general formula (2-1).

Further, for example, when m is 3, n is 3, and x is 2 in the above general formula (2), the diphosphinate metal salt includes a compound represented by the following general formula (2-2).

The above alkyl groups include linear or branched saturated aliphatic groups. Examples of the above aryl groups include aromatic groups having 6 to 20 carbon atoms which are unsubstituted or substituted with various substituents. Specific examples thereof include phenyl group, benzyl group, o-toluyl group, 2,3-xylyl group and the like.

Examples of the metal phosphinic acid salts include phosphinic acid and metal carbonates, metal hydroxides, metal oxides, etc., as described in European Patent Application Publication No. 699708 and Japanese Patent Application Laid-Open No. 8-73720. can be produced in an aqueous solution using a metal component of These are essentially monomeric compounds, but also polymeric metal phosphinates with a degree of condensation of 1 to 3 depending on the circumstances and depending on the reaction conditions.

Phosphinic acids and diphosphinic acids that form metal phosphinic acid salts are not particularly limited, and examples include dimethylphosphinic acid, ethylmethylphosphinic acid, diethylphosphinic acid, methyl-n-propylphosphinic acid, methanedi(methylphosphinic acid), and benzene. -1,4-di(methylphosphinic acid), methylphenylphosphinic acid, diphenylphosphinic acid and the like.

The metal component forming the metal phosphinate is not particularly limited, and examples thereof include calcium ions, magnesium ions, aluminum ions, zinc ions and the like.

The metal phosphinate is not particularly limited, and examples thereof include calcium dimethylphosphinate, magnesium dimethylphosphinate, aluminum phosphinate, aluminum dimethylphosphinate, zinc phosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, and ethylmethylphosphine. magnesium acid, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, magnesium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate, calcium methyl-n-propylphosphinate, methyl-n-propylphosphine magnesium acid, aluminum methyl-n-propylphosphinate, zinc methyl-n-propylphosphinate, calcium methylenebis(methylphosphinate), magnesium methylenebis(methylphosphinate), aluminum methylenebis(methylphosphinate), methylenebis(methylphosphinate) ) zinc, phenylene-1,4-bis(methylphosphinate)calcium, phenylene-1,4-bis(methylphosphinate)magnesium, phenylene-1,4-bis(methylphosphinate)aluminum, phenylene-1,4 - zinc bis(methylphosphinate), calcium methylphenylphosphinate, magnesium methylphenylphosphinate, aluminum methylphenylphosphinate, zinc methylphenylphosphinate, calcium diphenylphosphinate, magnesium diphenylphosphinate, aluminum diphenylphosphinate and diphenyl zinc phosphinate. Among these, aluminum phosphinate and zinc phosphinate are preferred, and aluminum phosphinate is more preferred, in terms of more excellent flame retardancy.

The metal phosphinate flame retardants may be used singly or in combination of two or more.

The content of the metal phosphinate flame retardant in the transparent resin layer is preferably 5% by mass or more, more preferably 6% by mass or more, based on 100% by mass of the transparent resin layer. The content of the metal phosphinate flame retardant in the transparent resin layer is preferably 30% by mass or less, more preferably 20% by mass or less, and 15% by mass or less, based on 100% by mass of the transparent resin layer. More preferably, 10% by mass or less is particularly preferable. When the lower limit of the content of the metal phosphinate-based flame retardant is within the above range, the flame retardancy of the resin sheet and the difficulty of spreading fire are further improved. Further, when the upper limit of the content of the metal phosphinate flame retardant is within the above range, whitening of the resin sheet due to bending is further suppressed.

The transparent resin layer contains at least one resin selected from the group consisting of polyolefin resins and polyester resins.

As the polyolefin-based resin, a polyolefin-based thermoplastic resin is preferable, and an olefin-based thermoplastic elastomer is more preferable in that whitening caused by bending of the resin sheet is further suppressed.

More specifically, polyolefin resins include polyethylene, ethylene-α-olefin copolymer, polypropylene, polymethylpentene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, and ethylene-vinyl acetate copolymer. , ethylene-vinyl acetate copolymer saponified products, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, and the like. Among these, polypropylene is preferred.

Polyester-based thermoplastic resins can be used as polyester-based resins, and polyethylene terephthalate, polyalkylene terephthalate with high heat resistance [for example, polyethylene obtained by substituting a portion of ethylene glycol with 1,4-cyclohexanedimethanol, diethylene glycol, etc. terephthalate, so-called PET-G (manufactured by Eastman Chemical Company)], polybutylene terephthalate, polyethylene naphthalate, polyethylene naphthalate-isophthalate copolymer, and the like. Among these, polyalkylene terephthalate having high heat resistance is preferable.

The transparent resin layer may be colored as long as it has transparency. In this case, a colorant may be added to the thermoplastic resin. As the coloring agent, pigments or dyes used in the pattern layer can be used.

Fillers, delustering agents, foaming agents, lubricants, antistatic agents, antioxidants, UV absorbers, light stabilizers, radical scavengers, soft components (e.g. rubber), etc. are added to the transparent resin layer. of additives may be included.

The filler is not particularly limited as long as it does not impair the transparency of the transparent resin layer, and examples thereof include inorganic fillers such as silica, calcium carbonate, talc and clay.

The filler is not limited to the transparent resin layer, and may be contained in the transparent resin layer and/or the base sheet.

The transparent resin layer preferably further contains an inorganic filler having a polar group on its surface. When the transparent resin layer containing the metal phosphinate flame retardant contains an inorganic filler having a polar group on its surface, the flame retardancy of the resin sheet and the difficulty of spreading fire are further improved. This is because the polar part of the metal phosphinate flame retardant is attracted to the polar group on the surface of the inorganic filler having a polar group, and the presence of the metal phosphinate flame retardant on the surface improves the dispersibility. It is considered to be As the inorganic filler having a polar group on the surface, a hydrophilic inorganic filler can be used. Examples thereof include inorganic fillers having a hydroxyl group such as a silanol group on the surface. More specifically, hydrophilic silica can be used. can be done.

Silica used as a filler may be either a natural product or a synthetic product, and may be either crystalline or amorphous. Moreover, the synthetic amorphous silica may be prepared by either a wet method or a dry method. A method for preparing synthetic wet-process silica prepared by a wet process is not particularly limited, and examples thereof include a precipitation method and a gel method. The method for preparing the synthetic dry process silica prepared by the dry process is not particularly limited, and examples thereof include the combustion method and the arc method. From the viewpoint of further improving the sharpness of the resin sheet, silica having a small average particle size is preferable, and fumed silica obtained by a combustion method and hydrophilic fumed silica are more preferable.

The BET specific surface area of the filler such as hydrophilic fumed silica is preferably 50 m ² /g or more, more preferably 130 m ² /g or more, and even more preferably 200 m ² /g or more. When the lower limit of the BET specific surface area of the filler is within the above range, the average particle size is small, and in the case of hydrophilic fumed silica, the amount of silanol increases. The deterioration of the properties is further suppressed, the dispersibility of the metal phosphinate flame retardant is further improved, and the sharpness and flame retardancy of the resin sheet are further improved. Moreover, when the lower limit of the BET specific surface area of the filler is within the above range, the flame retardancy of the resin sheet is improved, and the content of the metal phosphinate flame retardant can be reduced.

As used herein, the BET specific surface area is a BET specific surface area measured by a nitrogen adsorption method according to a measuring method based on DIN66131.

Commercially available hydrophilic fumed silica can be used as a filler. Examples of such commercial products include AEROSIL 50, AEROSIL 130, AEROSIL 200, AEROSIL 300, AEROSIL 380 and the like manufactured by Nippon Aerosil Co., Ltd.

When the transparent resin layer contains a metal phosphinate flame retardant and a filler, the content of the filler in the transparent resin layer is equal to the content of the metal phosphinate flame retardant in the transparent resin layer. As 100 parts by mass, it is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and even more preferably 200 parts by mass or more. By setting the lower limit of the content of the filler in the transparent resin layer within the above range, the sharpness of the resin sheet is further improved. In addition, the content of the filler in the transparent resin layer is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 10 parts by mass or less based on 100 parts by mass of the resin component in the transparent resin layer. preferable.

The thickness of the transparent resin layer is preferably 60 μm or more, more preferably 80 μm or more. Moreover, the thickness of the transparent resin layer is preferably 300 μm or less, more preferably 200 μm or less. When the lower limit of the thickness of the transparent resin layer is within the above range, the scratch resistance and abrasion resistance of the resin sheet are further improved. In addition, since the upper limit of the thickness of the transparent resin layer is within the above range, the flame of the resin sheet is more difficult to spread.

If necessary, the surface of the transparent resin layer may be subjected to surface treatment such as corona discharge treatment, ozone treatment, plasma treatment, ionizing radiation treatment, and dichromic acid treatment. The surface treatment may be carried out according to a conventional method for each treatment.

A primer layer (primer layer for facilitating formation of a surface protective layer) may be formed on the surface of the transparent resin layer.

The primer layer can be formed by applying a known primer agent to the transparent resin layer. Examples of primer agents include urethane resin-based primer agents composed of acrylic-modified urethane resins and the like, and resin-based primer agents composed of block copolymers of acrylic and urethane.

Although the thickness of the primer layer is not particularly limited, it is usually about 0.1 to 10 μm, preferably about 1 to 5 μm.

(Surface protective layer)
The resin sheet of the present invention may have a surface protective layer (transparent surface protective layer). The surface protective layer is provided to impart surface physical properties such as scratch resistance, abrasion resistance, water resistance, and stain resistance required for the resin sheet.

The resin sheet of the present invention preferably has a surface protective layer on the opposite side of the transparent resin layer to the base sheet, such as the outermost surface. By having a surface protective layer on the outermost surface, together with the fact that the surface protective layer contains at least one kind of curable resin as described later, the decomposition of the resin in the layer below the surface protective layer in the event of a fire or the like The surface protective layer delays the generation of combustion gas, further improving the difficulty of spreading fire.

The resin forming the surface protective layer preferably contains at least one curable resin such as a thermosetting resin or an ionizing radiation curable resin. In particular, ionizing radiation-curable resins are preferable from the viewpoint of high surface hardness, productivity, and the like. Furthermore, from the viewpoint of being able to further improve the weather resistance, an electron beam curable resin is most preferred. In addition, as described above, from the viewpoint of delaying the generation of combustion gas due to the decomposition of the resin in the layer below the surface protective layer in the event of a fire or the like, ionizing radiation curing, which is a curable resin with a high crosslink density among curable resins, is used. A mold resin is preferred, and an electron beam curable resin is more preferred.

Thermosetting resins include, for example, unsaturated polyester resins, polyurethane resins (including two-component curing polyurethanes), epoxy resins, aminoalkyd resins, phenolic resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, and melamine. - urea co-condensation resin, silicone resin, polysiloxane resin and the like.

A crosslinking agent, a curing agent such as a polymerization initiator, and a polymerization accelerator can be added to the above resin. For example, as curing agents, isocyanates, organic sulfonates and the like can be added to unsaturated polyester resins and polyurethane resins, organic amines and the like can be added to epoxy resins, peroxides such as methyl ethyl ketone peroxide, and azoisobutylnitrile can be added. A radical initiator can be added to the unsaturated polyester resin.

Examples of the method of forming the surface protective layer with a thermosetting resin include a method of applying a thermosetting resin solution by a coating method such as a roll coating method or a gravure coating method, followed by drying and curing. The coating amount of the solution is about 5 to 50 μm, preferably about 5 to 40 μm in terms of solid content.

The ionizing radiation-curable resin is not limited as long as it is a resin that undergoes a cross-linking polymerization reaction when irradiated with ionizing radiation and changes into a three-dimensional polymer structure. For example, one or more of prepolymers, oligomers and monomers having polymerizable unsaturated bonds or epoxy groups in the molecule that can be crosslinked by irradiation with ionizing radiation can be used. Examples thereof include acrylate resins such as urethane acrylate, polyester acrylate and epoxy acrylate; silicone resins such as siloxane; polyester resins; and epoxy resins.

Ionizing radiation includes visible light, ultraviolet rays (near ultraviolet rays, vacuum ultraviolet rays, etc.), X-rays, electron beams, ion beams, etc. Among these, ultraviolet rays and electron beams are preferred, and electron beams are more preferred.

Ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arc lamps, black light fluorescent lamps, and metal halide lamps can be used as ultraviolet light sources. The wavelength of ultraviolet rays is about 190 to 380 nm.

As the electron beam source, for example, various electron beam accelerators such as Cockcroftwald type, Vandegraft type, resonance transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type can be used. The electron beam energy is preferably about 100 to 1000 keV, more preferably about 100 to 300 keV. The electron beam irradiation dose is preferably about 20 to 150 KGy.

Ionizing radiation-curable resins are sufficiently cured by irradiation with electron beams, but when curing by irradiation with ultraviolet rays, it is preferable to add a photopolymerization initiator (sensitizer).

Photoinitiators for resin systems having radically polymerizable unsaturated groups include, for example, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether, Michler benzoyl benzoate, Michler ketone, diphenyl sulfide, dibenzyl disulfide. , diethyl oxide, triphenylbiimidazole, isopropyl-N,N-dimethylaminobenzoate and the like can be used. In the case of a resin system having a cationic polymerizable functional group, for example, at least one of aromatic diazonium salts, aromatic sulfonium salts, metallocene compounds, benzoinsulfonic acid esters, freeloxysulfoxonium diallyiodosyl salts, and the like. can be used.

Although the amount of the photopolymerization initiator added is not particularly limited, it is generally about 0.1 to 10 parts by weight per 100 parts by weight of the ionizing radiation-curable resin.

As a method for forming a protective layer with an ionizing radiation-curable resin, for example, a solution of an ionizing radiation-curable resin may be applied by a coating method such as gravure coating or roll coating. The coating amount of the solution is about 10 to 50 μm, preferably about 15 to 40 μm in solid content.

The thickness of the surface protective layer is preferably 4 µm or more, more preferably 8 µm or more, still more preferably 10 µm or more, and particularly preferably 12 µm or more. The thickness of the surface protective layer is preferably 50 µm or less, more preferably 40 µm or less, still more preferably 30 µm or less, and particularly preferably 20 µm or less. When the lower limit of the thickness of the surface protective layer is within the above range, the scratch resistance and wear resistance of the resin sheet are further improved. In addition, when the upper limit of the thickness of the surface protective layer is within the above range, the flame retardancy of the resin sheet is further improved, appropriate rigidity is obtained, and the handleability of the resin sheet is improved.

In this specification, the thickness of the surface protective layer refers to the thickness of the surface protective layer, as shown in FIG. The point is measured as the surface of the surface protective layer. Moreover, as shown in FIG. 1, when the resin sheet is embossed to form an uneven shape, the thickness of the surface protective layer is measured at a portion other than the uneven shape.

Fine particles 16 may be blended as shown in FIG. 1 in order to further impart scratch resistance and abrasion resistance to the surface protective layer or to reduce luster. Examples of fine particles include inorganic fillers and organic fillers. Examples of inorganic fillers include mica, powdered aluminum oxide, silicon carbide, silicon dioxide, calcium titanate, barium titanate, magnesium pyroborate, zinc oxide, silicon nitride, zirconium oxide, chromium oxide, iron oxide, nitriding. Boron, diamond, emerald, glass fiber and the like can be mentioned. Examples of organic fillers include acrylic beads and cellulose.

The average particle size of the fine particles is not particularly limited, and is preferably larger than the thickness of the surface protective layer when further imparting scratch resistance and abrasion resistance to the surface protective layer. When the average particle size of the fine particles is larger than the thickness of the surface protective layer, the scratch resistance and wear resistance of the resin sheet are further improved by the protrusion of the fine particles. The average particle size of fine particles for further imparting scratch resistance and wear resistance to the surface protective layer is more than 15 μm, preferably 50 μm or less, more preferably 16 to 35 μm, most preferably 16 to 20 μm.

The average particle size of fine particles used as a matting agent for reducing the luster of the surface protective layer is preferably 3 to 15 μm, more preferably 4 to 15 μm, most preferably 8 to 15 μm. When the average particle size of the fine particles used as the matting agent is within the above range, the luster of the surface protective layer can be further reduced.

Further, when imparting scratch resistance to the surface protective layer, fine particles having a smaller average particle size may be used. The average particle size of fine particles for imparting scratch resistance to the surface protective layer is preferably 1 to 5 μm, more preferably 3 to 5 μm, even more preferably 3 to 4 μm. When the average particle diameter of the fine particles for imparting scratch resistance to the surface protective layer is within the above range, the hardness of the surface protective layer is further increased, and the scratch resistance of the surface protective layer is further improved.

In the present specification, the average particle size of fine particles is the mode size. In addition, the mode diameter is the particle diameter showing the maximum value of the particle diameter distribution, and is the particle diameter with the largest appearance ratio.

The amount of the inorganic filler to be added is about 1 to 80 parts by mass with respect to 100 parts by mass of the ionizing radiation curable resin.

The surface protective layer preferably contains the metal phosphinate flame retardant. When the surface protective layer contains the metal phosphinate-based flame retardant, it is possible to further improve the flame retardancy by forming char against heat applied from the surface of the resin sheet of the present invention and trapping combustion gas. can.

The content of the metal phosphinate flame retardant in the surface protective layer is preferably 1 to 20 parts by mass, more preferably 3 to 10 parts by mass, based on 100 parts by mass of the ionizing radiation-curable resin.

The lamination of each layer described above can be performed, for example, by forming a picture pattern layer (solid ink layer, pattern ink layer) on one side of the base material sheet by printing, and then applying a known liquid such as a two-pack curable urethane resin on the picture pattern layer. A transparent resin layer may be laminated via a dry lamination adhesive by a dry lamination method, a T-die extrusion lamination method, or the like, and a surface protective layer may be formed.

The total thickness of the resin sheet is preferably 110 µm or more, more preferably 120 µm or more. Moreover, the total thickness of the resin sheet is preferably 400 μm or less, more preferably 250 μm or less. When the lower limit of the total thickness of the resin sheet is within the above range, the scratch resistance and abrasion resistance of the resin sheet are further improved. In addition, since the upper limit of the total thickness of the resin sheet is within the above range, the fire of the resin sheet is more difficult to spread.

In this specification, the total thickness of the resin sheet is defined as td in FIG. The point is measured as the surface of the resin sheet. Moreover, as shown in FIG. 1, when the resin sheet is embossed to form an uneven shape, the total thickness of the resin sheet is measured at locations other than the uneven shape.

The resin sheet may be embossed from the transparent resin layer side (upper side of the resin sheet) to form an uneven shape (embossed shape). For example, the resin sheet of the present invention may have unevenness on the side of the transparent resin layer opposite to the base sheet. The uneven shape can be formed by hot pressing, hairline processing, or the like. Examples of the uneven shape include wood grain conduit grooves, slate surface unevenness, cloth surface texture, satin finish, sand grain, hairline, parallel line grooves, and the like.

(Synthetic resin backer layer)
The resin sheet and decorative sheet may have a synthetic resin backer layer as long as the flame retardancy is not impaired. By having the synthetic resin backer layer, the impact resistance of the resin sheet and the decorative sheet is further improved.

Examples of the resin constituting the synthetic resin backer layer include polypropylene, ethylene-vinyl alcohol copolymer, polymethylene, polymethylpentene, polyethylene terephthalate, polyalkylene terephthalate with high heat resistance [e.g. So-called PET-G (manufactured by Eastman Chemical Company), which is polyethylene terephthalate substituted with ,4-cyclohexanedimethanol, diethylene glycol, etc.], polybutylene terephthalate, polyethylene naphthalate, polyethylene naphthalate-isophthalate copolymer, Examples include polycarbonate, polyarylate, polyimide, polystyrene, polyamide, and ABS. These resins can be used singly or in combination of two or more.

The synthetic resin backer layer may be colored in the same manner as the transparent resin layer. In this case, a coloring agent may be added to the synthetic resin. As the coloring agent, pigments or dyes used in the pattern layer can be used.

As with the transparent resin layer, the synthetic resin backer contains fillers, matting agents, foaming agents, lubricants, antistatic agents, antioxidants, ultraviolet absorbers, light stabilizers, radical scavengers, soft ingredients ( For example, rubber), flame retardants, and various other additives may be included.

Examples of fillers include inorganic fillers such as silica, calcium carbonate, talc and clay.

The flame retardant is not particularly limited, and can be used regardless of whether it is inorganic or organic.

The thickness of the synthetic resin backer layer is preferably 0.1 to 0.6 mm, more preferably 0.15 to 0.45 mm, even more preferably 0.20 to 0.40 mm. By setting the lower limit of the thickness of the synthetic resin backer layer within the above range, the impact resistance of the resin sheet and the decorative sheet is further improved. Moreover, since the upper limit of the thickness of the synthetic resin backer layer is within the above range, warping of the resin sheet and the decorative sheet is further suppressed.

Various additives added to each layer of the resin sheet of the present invention (magnesium hydroxide contained in the base sheet, metal phosphinate flame retardant contained in the transparent resin layer, etc.) are It is preferably vesicled. The method for forming various additives into vesicles is not particularly limited, and vesicle formation can be performed by a known method, and among them, the supercritical reverse phase evaporation method is preferred.

The supercritical reverse phase evaporation method will be described in detail below. The supercritical reverse phase evaporation method is a method in which a water-soluble or hydrophilic In this method, an aqueous phase containing various additives as encapsulating substances is added to form capsule-like vesicles containing various additives as encapsulating substances with a single layer film. In addition, carbon dioxide in a supercritical state means carbon dioxide in a supercritical state with a critical temperature (30.98 ° C.) and a critical pressure (7.3773 ± 0.0030 MPa) or higher, and a temperature above the critical point or Carbon dioxide under pressure conditions means carbon dioxide under conditions where only the critical temperature or only the critical pressure exceeds the critical conditions. By this method, unilamellar lamellar vesicles with a diameter of 50-800 nm can be obtained. In general, vesicles are a general term for vesicles having a closed spherical membrane structure that contain a liquid phase inside. In particular, vesicles whose outer membrane is composed of biological lipids such as phospholipids are called liposomes. .

Phospholipids include phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylglycerol, phosphatidylinositol, cardiolipin, egg yolk lecithin, hydrogenated egg yolk lecithin, soybean lecithin, glycerophospholipids such as hydrogenated soybean lecithin, and sphingomyelin. , ceramide phosphorylethanolamine, and ceramide phosphorylglycerol.

Nonionic surfactants and dispersing agents such as mixtures of nonionic surfactants with cholesterols or triacylglycerols can also be used as the substance constituting the outer membrane.

Examples of the nonionic surfactant include polyglycerin ether, dialkylglycerin, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkyl ether, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, polyoxyethylene polyoxypropylene copolymer, polybutadiene- One or two of polyoxyethylene copolymer, polybutadiene-poly2-vinylpyridine, polystyrene-polyacrylic acid copolymer, polyethylene oxide-polyethylethylene copolymer, polyoxyethylene-polycaprolactam copolymer, etc. The above can be used.

Examples of the cholesterols include one or more of cholesterol, α-cholestanol, β-cholestanol, cholesterol, desmosterol (5,24-cholestadien-3β-ol), sodium cholate, cholecalciferol, and the like. can be used.

The liposome outer membrane may be formed from a mixture of a phospholipid and a dispersing agent. In the resin sheet of the present invention, the compatibility between the resin composition, which is the main component of each layer, and various additives can be improved by using liposomes formed from phospholipids as the outer membrane.

(NOR type hindered amine compound)
The resin sheet of the present invention preferably contains a NOR-type hindered amine compound in the transparent resin layer and/or the base sheet. Since the NOR-type hindered amine compound can trap radicals generated from organic substances during combustion and make it difficult to continue combustion, at least one layer of the thermoplastic resin layers containing a hindered amine compound can achieve ISO 5660-1. In the exothermic test according to, the calorific value can be further reduced. From the viewpoint of further improving the above effects, the resin sheet of the present invention has a configuration in which the metal phosphinate flame retardant and the NOR-type hindered amine compound are contained in the same layer, that is, the resin sheet is contained in the transparent resin layer. It is more preferable to have a configuration that

As the NOR-type hindered amine compound, for example, a compound represented by the following general formula (3) can be used.

In general formula (3), R ⁵ to R ⁸ each represent a hydrogen atom or an organic group represented by general formula (4) below. At least one of R ⁵ to R ⁸ is an organic group represented by general formula (4) below.

In general formula (4), R ⁹ represents an alkyl group having 1 to 17 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, a phenyl group or a phenylalkyl group having 7 to 15 carbon atoms, and R ¹⁰ , R ¹¹ , R ¹² and R ¹³ each represent an alkyl group having 1 to 4 carbon atoms. R ¹⁴ represents a hydrogen atom or a linear or branched alkyl group having 1 to 12 carbon atoms.

The alkyl group having 1 to 17 carbon atoms for R ⁹ is preferably a methyl group or an octyl group. Moreover, the cycloalkyl group having 5 to 10 carbon atoms is preferably a cyclohexyl group. A phenyl group or a phenylalkyl group having 7 to 15 carbon atoms is preferably a phenyl group. The alkyl group having 1 to 4 carbon atoms represented by R ¹⁰ to R ¹³ is preferably a methyl group. The linear or branched alkyl group having 1 to 12 carbon atoms for R ¹⁴ is preferably an n-butyl group.

In general formula (3), R ⁵ , R ⁶ and R ⁷ are organic groups of general formula (4), or R ⁵ , R ⁶ and R ⁸ are organic groups of general formula (4) things are preferred.

Specific examples of NOR-type hindered amine compounds include N,N′,N′″-tris{2,4-bis[(1-hydrocarbioxy-2,2,6,6-tetramethylpiperidine-4- yl)alkylamino]-s-triazin-6-yl}-3,3′-ethylenediiminodipropylamine, N,N′,N″-tris{2,4-bis[(1-hydrocarbioxy -2,2,6,6-tetramethylpiperidin-4-yl)alkylamino]-s-triazin-6-yl}-3,3′-ethylenediiminodipropylamine and its bridged derivatives, bis(1 -octyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)adipate, bis(1 -cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)adipate and bis(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate, and 1 -cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl-octadecanoate and the like.

The NOR-type hindered amine compounds may be used singly or in combination of two or more.

The content of the NOR-type hindered amine compound in each layer of the thermoplastic resin layer containing the NOR-type hindered amine compound is preferably 0.2 to 5% by mass, and preferably 0.5%, based on 100% by mass of the layer containing the NOR-type hindered amine compound. ~3% by mass is more preferred.

Since the resin sheet of the present invention has the structure described above, even when the resin sheet is laminated on a base material having low thermal conductivity, it is difficult for fire to spread. Therefore, it can be used as a resin sheet to be laminated on a substrate having a thermal conductivity of less than 0.1 W / (m K), and even when laminated on the substrate, the fire does not easily spread. . Therefore, the resin sheet of the present invention can be suitably used as a decorative sheet, particularly as a decorative sheet for interior materials and a decorative sheet for floors.

2. Decorative Board The decorative board of the present invention is a decorative board having the above resin sheet on a base material.

(resin sheet)
As the resin sheet constituting the decorative board of the present invention, the resin sheet of the present invention described above can be used.

(Base material)
The material of the substrate is not particularly limited, and an inorganic substrate such as a metal plate such as a galvanized steel plate or an aluminum plate may be used. may be used. For example, as shown in FIG. 2, a wooden base material may be used in which a surface material 22 made of a material exhibiting thermal conductivity within the above range is laminated on a wooden board 21 that is commonly used for a decorative board such as a decorative board for floors. . Moreover, FIG. 3 shows an example of the layer structure of the decorative sheet of the present invention using the substrate of FIG. In FIG. 3, the surface material 22 of the base material 2 and the base sheet 12 of the resin sheet 1 are bonded together, and the resin sheet 1 is laminated on the base material 2 to form a decorative board.

The surface material is not particularly limited, and examples thereof include cork, paulownia, medium density fiberboard (MDF), high density fiberboard (HDF) and the like, and these may be used in combination. Among these, cork is preferably used because it can impart heat retention and cushioning properties to the decorative board. That is, the substrate preferably has a cork layer on the resin sheet side.

The thickness of the surface material is not particularly limited, and is preferably 1.0 to 5.0 mm, more preferably 1.0 to 2.5 mm.

The wood board is not particularly limited, and examples thereof include medium density fiberboard (MDF), high density fiberboard (HDF), and plywood. Among these, plywood is preferably used.

The thickness of the wooden board is not particularly limited, and is preferably 4.0 to 15.0 mm, more preferably 5.0 to 10.0 mm.

The method for laminating the surface material and the wooden board is not particularly limited, and the lamination can be performed by a conventionally known method such as lamination with an adhesive. The adhesive is not particularly limited, and a wide range of known woodworking adhesives can be used. Examples of adhesives include polyvinyl acetate, polyvinyl chloride, urethane, acrylic, acrylic urethane, vinyl chloride-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ionomer, butadiene-acrylonitrile rubber, neoprene rubber, Adhesives containing natural rubber or the like as an active ingredient can be mentioned. Further, examples of thermosetting adhesives include melamine-based, phenol-based, and urea-based (vinyl acetate-urea-based, etc.) adhesives.

The substrate constituting the decorative board of the present invention may have a thermal conductivity of less than 0.1 W/(m·K) on the side to which the resin sheet is adhered. In addition, in this specification, the thermal conductivity of a base material is thermal conductivity measured by the following measuring methods.

(Method for measuring thermal conductivity of substrate)
A sample for measurement is prepared by cutting out a circular material with a diameter of 40 mm from the material forming the layer on the side of the base material to which the resin sheet is adhered. The measurement samples are stacked in the thickness direction to form an even number of layers so that the thickness exceeds 15 mm. Next, a sensor is sandwiched between half of the laminated measurement samples, and the thermal conductivity is measured by the hot disk method in accordance with ISO 22007-2:2008. It is assumed that an air layer included between adjacent measurement samples when the measurement samples are stacked can be ignored.

An example of a method for measuring thermal conductivity is shown. A cork having a diameter of 40 mm and a thickness of 1.5 mm is prepared as a measurement sample. Thirty measurement samples are laminated so that the total thickness of the measurement samples exceeds 15 mm. This results in a laminate of 45 mm. Next, a sensor is sandwiched between the 15th and 16th measurement samples (at a position of 22.5 mm), which is half the thickness of the laminate, and ISO 22007-2: In accordance with 2008, a hot disk The thermal conductivity is measured by the method.

In addition, when cork with a thickness of 2.0 mm is used as a measurement sample, the thickness of the laminate becomes 40 mm when 20 corks are stacked. good.

In addition, when cork with a thickness of 1.0 mm is used as a measurement sample, the thickness of the laminate becomes 40 mm when 40 corks are stacked. good.

The method for laminating the resin sheet on the front surface of the base material is not particularly limited, and lamination is performed by a conventionally known method such as forming an adhesive layer on the front surface of the base material and laminating the resin sheet. be able to.

The thickness of the adhesive layer is not particularly limited, and the thickness after drying is preferably 0.1 to 100 μm, more preferably 0.1 to 30 μm, even more preferably 1 to 20 μm.

Examples of adhesives used in the adhesive layer include water-soluble emulsion-based adhesives, polyester-based adhesives, acrylic-based adhesives, urethane-based adhesives, and the like. Adhesives can be used alone or in combination of two or more.

Since the decorative sheet of the present invention has the structure described above, it is excellent in flame retardancy and can exhibit high sharpness. Therefore, the decorative board of the present invention can be suitably used as a decorative board for interior materials, particularly as a decorative board for floors.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to the examples.

Example 1
(Manufacture of resin sheet)
As a base sheet, a 60 μm-thick opaque colored polypropylene film containing 10% by mass of magnesium hydroxide (product name: Magshees N-6 (manufactured by Kamishima Chemical Co., Ltd.)) was prepared. Next, after subjecting both sides of the base sheet to corona discharge treatment, a primer layer (thickness 2 μm) of a two-component curing type urethane resin is formed on the back surface of the base sheet, and the front surface of the base sheet is coated with A pattern layer was formed by gravure printing using a curable printing ink containing an acrylic urethane resin. Further, a transparent adhesive layer was formed by applying a two-liquid curable urethane resin adhesive onto the pattern layer. Furthermore, on the adhesive layer, a T-die extruder is used to heat and melt-extrude a transparent olefinic thermoplastic elastomer containing a metal phosphinate flame retardant shown below to form a transparent thermoplastic resin layer (thickness: 80 μm). ) was formed.

・Transparent olefin-based thermoplastic elastomer resin: 93% by mass
・ Aluminum phosphinate flame retardant (product name: Exolit OP-945 (manufactured by Clariant Japan Co., Ltd.)): 7% by mass

Next, after corona discharge treatment was applied to the surface of the transparent resin layer, a primer layer (thickness: 2 μm) of a two-liquid curing type urethane resin was formed on the transparent resin layer. Furthermore, after applying and drying an electron beam-curable resin composition containing a urethane (meth)acrylate oligomer on the primer layer by a gravure coating method, an electron beam is irradiated under the conditions of an acceleration voltage of 165 keV and an absorbed dose of 50 kGy. A surface protective layer was formed so as to have a thickness of 15 μm.

Next, the surface protective layer side is heated with an infrared non-contact type heater to soften the base sheet and the transparent resin layer, and then the surface protective layer side is immediately embossed by heat and pressure to form an uneven shape. did. The resin sheet of Example 1 was manufactured by the above manufacturing method.

(Manufacturing of Decorative Board A)
The surface of the base sheet side of the resin sheet manufactured as described above and the metal-based base material, which is a galvanized steel sheet with a thickness of 0.4 mm, are bonded together using a two-liquid curing polyester adhesive ( The adhesive was applied in an amount of 10 g/m ² ), and a pressure of 10 kgf/m ² was applied at 25° C. for 3 days to obtain the desired decorative sheet A.

(Manufacturing of Decorative Board B)
A cork sheet with a thickness of 1.5 mm was pasted onto a plywood with a thickness of 7.5 mm using an adhesive to prepare a wooden substrate.

Next, the base sheet side surface of the resin sheet was bonded to the cork sheet side surface of the wooden base material via a two-liquid curing water-soluble emulsion adhesive. The coating amount of the two-liquid curing water-soluble emulsion adhesive was 130 g/m ² .

Then, a pressure of 10 kgf/m ² was applied at 25° C. and cured for 3 days to obtain the desired decorative sheet B.

Examples 2 and 3, Comparative Examples 1-6
Table 1 was performed in the same manner as in Example 1, except that the components and contents of the resin composition constituting the transparent resin layer and the base sheet, and the thickness of each layer were changed as shown in Table 1. A resin sheet and a decorative board shown in were produced.

(evaluation)
The resin sheets and decorative boards of Examples and Comparative Examples manufactured as described above were evaluated by the following methods.

(1) Heat build- up test A burn test was performed using a cone calorimeter in accordance with ISO 5660-1 for a burn time of 20 minutes. Evaluation was made according to the following evaluation criteria. If both the total calorific value and the maximum calorific value are + or above, it is evaluated that there is no problem in actual use.
[Total calorific value]
+++: Less than 5.20 MJ/ ^m2 ++: 5.20 MJ/ ^m2 or more and less than 5.38 MJ/ ^m2 +: 5.38 MJ/ ^m2 or more and less than 5.55 MJ/ ^m2 -: 5.55 MJ/ ^m2 or more [maximum heat release rate]
+++: Less than 133.93KW/ ^m2 ++: 133.93KW/ ^m2 or more and less than 153.92KW/ ^m2 +: 153.92KW/ ^m2 or more and less than 173.93KW/ ^m2 -: 173.93KW/ ^m2 or more

(2) Horizontal flammability (difficulty in spreading fire)
The decorative board B was cut into a size of 9 cm×30 cm to obtain a test piece. As shown in FIGS. 4 and 5, a metal rectangular base 103 is placed on a base 102 of a commercially available household heater 101 (Zaigl Handsome SJ-100 (trade name)), and a metal A test piece 105 was placed in a frame 104 made of steel, and a test was conducted on the difficulty of spreading fire under the conditions of a heater angle of 45° and a heater output dial of 4. Specifically, the specimen was preheated for 2 minutes using the household heater described above. Next, as shown in FIG. 4, the end 106 of the test piece on the heater side in the longitudinal direction was heated with a lighter 107 for 1 minute and ignited to spread the fire in the longitudinal direction of the test piece 105 as shown in FIG. Next, the spread of fire was visually observed, and the combustion distance (L1) and combustion duration were evaluated as follows.

[Burning distance (L1)]
The fire spread distance from the initial ignition, when the test piece was ignited and the flame of the lighter was removed, was measured as the fire spread distance (L1) and evaluated according to the following evaluation criteria. If the evaluation is + or higher, it is evaluated that there is no problem in actual use.
++: L1 is less than 5 cm +: L1 is 5 cm or more and less than 10 cm -: L1 is 10 cm or more

[Burning Duration]
After igniting the test piece and removing the flame from the lighter, the duration of combustion from initial ignition to self-extinguishing was measured and evaluated according to the following evaluation criteria. If the evaluation is + or higher, it is evaluated that there is no problem in actual use.
+++: Combustion duration is less than 100 seconds, or no ignition ++: Combustion duration is 100 seconds or more and less than 300 seconds +: Combustion duration is 300 seconds or more and less than 600 seconds -: Combustion duration is 600 seconds or more (does not self-extinguish in 600 seconds)

(3) A 90° V-bending process was performed using the bending whitening decorative sheet A by the method shown in FIG. Specifically, as shown in (a), the decorative plate A was placed on the die 201 with the resin sheet 1 side of the decorative plate A facing the V-shaped die (receiving mold) 201 . Next, as shown in (b), a pressing die 203 having a tip R of 2 mm was pressed from the steel plate 202 side, and 90° bending press was performed. As a bending device, a one-arm screw press 100 (manufactured by Seiko Co., Ltd.) was used. As shown in (c), whether whitening occurred on the surface of the bent portion 1a of the resin sheet was observed visually or with a pocket microscope (magnification: 25). Observation is performed from the surface protective layer side of the resin sheet, from the viewpoint of the appearance of the transparent resin layer (whether it is cracked and whitened), and the visibility of the pattern layer existing under the transparent resin layer. from the point of view. Evaluation was made according to the following evaluation criteria. If the evaluation is + or higher, it is evaluated that there is no problem in actual use.
++: No whitening was observed, and the pattern design of the pattern layer was clearly visible +: Slight whitening was observed, but the pattern design of the pattern layer was visible -: Large whitening, The design of the pattern on the pattern layer cannot be seen.

Table 1 shows the results. In Table 1, "-" in the column for the composition of the transparent resin layer indicates that the transparent resin layer does not contain a metal phosphinate flame retardant, and the column for the composition of the base sheet. "-" indicates that the base sheet does not contain magnesium hydroxide.

1. resin sheet 12 . base sheet 13 . picture pattern layer 14 . transparent resin layer 15 . Surface protective layer 16. microparticles2. adherend 21 . wooden board 22 . surface material 101 . domestic heater 102 . Home heater base 103 . Metal rectangular platform 104 . metal frame 105 . Test piece 106. The longitudinal heater-side end 107 . Writer L1. Combustion distance 201. Die (receiving mold)
202. Galvanized steel plate 203. indentation die

Claims (10)

A resin sheet having a transparent resin layer on at least a base sheet,
(1) The transparent resin layer contains a metal phosphinate flame retardant,
(2) the base sheet contains magnesium hydroxide,
(3) The transparent resin layer and the base sheet contain at least one resin selected from the group consisting of polyolefin-based resins and polyester-based resins.
A resin sheet characterized by: The resin sheet according to claim 1, wherein the content of said magnesium hydroxide in said base sheet is 10% by mass or more. The resin sheet according to claim 1 or 2, wherein the metal phosphinate flame retardant is an aluminum phosphinate flame retardant. The resin sheet according to any one of claims 1 to 3, wherein the content of the metal phosphinate flame retardant in the transparent resin layer is 5% by mass or more. The resin sheet according to any one of claims 1 to 4, wherein the transparent resin layer contains a polyolefin resin, and the polyolefin resin is an olefin thermoplastic elastomer. 6. The resin sheet according to any one of claims 1 to 5, comprising at least a picture pattern layer and said transparent resin layer in this order on said base sheet. The resin sheet according to any one of claims 1 to 6, which has a surface protective layer on the opposite side of the transparent resin layer to the base sheet. The resin sheet according to claim 7, wherein the surface protective layer is an ionizing radiation-curable resin layer. The resin sheet according to any one of claims 1 to 8, wherein the transparent resin layer has an uneven surface on the opposite side of the base sheet. A decorative board having the resin sheet according to any one of claims 1 to 9 on a substrate.

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