JP2020157644A - Flame-retardant sheet - Google Patents

Abstract

To provide a flame-retardant sheet excellent in flame retardancy and heat insulation property.SOLUTION: There is provided a flame-retardant sheet 1 in which a base material layer 2, a first anchor layer 3 and a decorative layer 4 are layered in this order. The base material layer 2 includes a porous thermoplastic resin film having a void, and an inorganic material arranged in the void so that a gap remains in the void.SELECTED DRAWING: Figure 1

Description

The present invention relates to a flame retardant sheet.

Conventionally, there is a flame-retardant sheet in which a base material made of sheet-like fibers is coated with a flame-retardant resin. As such a flame-retardant sheet, a soft polyvinyl chloride-based resin, a polytetrafluoroethylene-based resin, or the like has been used as a coating resin. However, when a soft polyvinyl chloride resin is used as the coating resin, the plasticizer, flame retardant, etc. contained in the soft polyvinyl chloride resin exude to the surface layer over time, resulting in surface adhesiveness. In addition, there are problems that dirt in the air adheres and flexibility, weather resistance, flame retardancy, etc. are lowered.

On the other hand, in recent years, polymer materials for industrial use have been desired to be converted to environment-adaptive materials that do not place a burden on the environment due to problems of waste plastic treatment and environmental hormones. Specifically, due to problems such as dioxin generation during combustion and toxicity of plasticizers, conversion from polyvinyl chloride-based resins to polyolefin-based resins, for example, has been studied. However, since the polyolefin-based resin is a highly flammable resin, it is a difficult task to develop flame retardancy.

At present, in order to solve the above problems, a flame retardant is often kneaded into a polyolefin resin and used. Among the flame retardants, halogen-containing flame retardants are often used because they have a high flame retardant effect and relatively little deterioration in moldability and mechanical properties of molded products. However, when a halogen-containing flame retardant is used, halogen-based gas is generated during molding and combustion, which may cause corrosion of equipment. Therefore, from the viewpoint of safety, halogen-containing compounds are not used and non-halogen. A flame retardant treatment method is strongly desired (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 57-165437

In such a flame-retardant sheet, further improvement of flame-retardant and heat-insulating properties is required.
The present invention has been made by paying attention to the above-mentioned problems, and an object of the present invention is to provide a flame-retardant sheet having excellent flame retardancy and heat insulating properties.

In order to solve the above problems, one aspect of the present invention is a flame-retardant sheet in which a base material layer, an anchor layer and a decorative layer are laminated in this order, and the base material layer is a porous thermoplastic having pores. The gist is that the flame-retardant sheet includes a resin film and an inorganic material arranged so as to leave voids in the pores.

According to one aspect of the present invention, since the base material layer has an inorganic material and voids, it is possible to provide a flame-retardant sheet having excellent flame retardancy and heat insulating properties.

It is sectional drawing which shows the structure of the flame-retardant sheet which concerns on embodiment of this invention. It is sectional drawing which shows the base material layer enlarged.

Hereinafter, embodiments of the present technology will be described with reference to the drawings. In the description of the drawings, the same or similar parts are designated by the same or similar reference numerals, and duplicate description will be omitted. Each drawing is schematic and may differ from the actual one. The embodiments shown below exemplify devices and methods for embodying the technical idea of the present technology, and the technical idea of the present technology is specified in the devices and methods exemplified in the following embodiments. Not something to do. The technical idea of the present technology can be modified in various ways within the technical scope described in the claims. Further, the directions of "left and right" and "up and down" in the following description are merely definitions for convenience of explanation, and do not limit the technical idea of the present invention. Therefore, for example, if the paper surface is rotated 90 degrees, "left and right" and "up and down" are read interchangeably, and if the paper surface is rotated 180 degrees, "left" becomes "right" and "right" becomes "left". Of course, it becomes.

(Flame-retardant sheet)
In the flame-retardant sheet 1, as shown in FIG. 1, the first anchor layer 3 and the decorative layer 4 are laminated in this order on one surface of the base material layer 2 (hereinafter, also referred to as “front surface”). The second anchor layer 5 and the primer layer 6 are laminated in this order on the other surface of the base material layer 2 (hereinafter, also referred to as “back surface”). The outermost surface of the flame-retardant sheet 1 may be provided with an uneven pattern by embossing. By providing the uneven pattern, it is possible to prevent the echo of the sound.

In addition, the flame-retardant sheet 1 has a maximum heat generation rate of 350 kW when it is heated and burned for 30 minutes under radiant heating conditions of 50 kW / m ² in a combustion test based on ASTM E 1354 "Combustibility test method for building materials". / preferably m ² or less, more preferably 300 kW / m ² or less. If the maximum heat generation rate of the flame retardant sheet 1 exceeds 350 kW / m ² , sufficient flame retardancy may not be exhibited.
Further, the flame-retardant sheet 1 is a combustion residue obtained by heating and burning for 30 minutes under radiant heating conditions of 50 kW / m ² in a combustion test based on ASTM E 1354 at a rate of 0.1 cm / sec. The yield point stress when compressed is preferably 4.9 × 10 ³ Pa or more. If the yield point stress is less than 4.9 × 10 ³ Pa, the combustion residue easily collapses due to a slight impact, and a drip phenomenon occurs on the flame-retardant sheet 1 itself or a decorative plate using this flame-retardant sheet 1 in the event of a fire. May occur and there is a risk of fire spreading.

Further, the flame-retardant sheet 1 preferably has a flame-retardant performance of second grade or higher as defined in JIS A 1322 “Flame-retardant test method for thin materials for construction”. If the flameproof performance does not satisfy the above-mentioned regulations, sufficient flame retardancy may not be exhibited and the practicality may be insufficient.
Further, the flame-retardant sheet 1 preferably has a flameproof performance of Category 3 or higher specified in JIS L 1091 “Flameability test method for textile products”. If the flame-retardant performance of the flame-retardant sheet 1 does not satisfy the above-mentioned regulation, sufficient flame-retardant property may not be exhibited and the practicality may be insufficient.

In addition, the flame-retardant sheet 1 is non-flammable by satisfying the following requirements in the heat generation test by a cone calorimeter tester conforming to ISO5660-1 in the technical standard of non-combustible material specified in the Building Standard Law Construction Ordinance. It is preferable to have it (Building Standard Law Construction Ordinance Article 108-2 No. 1 and No. 2). In order to be certified as nonflammable, it is necessary to satisfy all of the following requirements 1 to 3 in a heating time of 20 minutes by heating with radiant heat of 50 kW / m ^{2 in} a state of being bonded to a nonflammable base material. ..
1. 1. Total calorific value is 8MJ / m ² or less 2. 2. The maximum heat generation rate does not exceed 200 kW / m ² continuously for 10 seconds or more. No cracks or holes penetrate to the back surface, which is harmful for flameproofing. The nonflammable base material can be selected from gypsum board, fiber-mixed calcium silicate plate, and galvanized steel plate.

(Base material layer)
As shown in FIG. 2, the base material layer 2 has a porous thermoplastic resin film 2a and an inorganic material 2c arranged in the pores 2b of the thermoplastic resin film 2a. When the thermoplastic resin 2a (for example, a polyolefin resin alone) is formed into a film, there is no space and the cross section is tightly packed. However, the inorganic material 2c is added to the thermoplastic resin 2a and stretched. Then, a space is generated around the inorganic material 2c. In the present embodiment, this generated space is referred to as a hole 2b. The presence or absence of pores 2b can be confirmed by observing the periphery of the inorganic material 2c in the cross section of the base material layer 2 using a scanning electron microscope (SEM). By having the inorganic material 2c in the thermoplastic resin film 2a, it is possible to obtain nonflammability and flame retardancy.
The internal space of the pores 2b is formed to be slightly larger than that of the inorganic material 2c. Inside the pores 2b, voids 2d remain around the inorganic material 2c. Since the gap 2d remains, heat insulation, sound insulation, high concealment, and weight reduction are possible, which is preferable for ceiling panel applications.
The porosity of the thermoplastic resin film 2a is, for example, preferably 10% by volume or more and 95% by volume or less, and more preferably 50% by volume or more and 85% by volume or less. If the porosity is less than 10% by volume, the resin becomes rich, so that the adhesiveness and the adhesiveness may be lowered. On the other hand, if the porosity is larger than 95% by volume, the strength of the base material layer 2 may be difficult. The porosity can be adjusted by adjusting the adjusted draw ratio, the amount of the inorganic material added, and the particle size.

As the thermoplastic resin constituting the thermoplastic resin film 2a, for example, a polyolefin resin, a polyester resin, or the like can be used. Examples of the polyolefin-based resin include ethylene homopolymers, propylene homopolymers, ethylene and / or copolymers of propylene and other α-olefins copolymerizable with these, ethylene-ethyl acrylate copolymers, and the like. It is preferably at least one selected from the group consisting of ethylene-vinyl acetate copolymers. As at least one selected, for example, polyethylene, polypropylene, polybutene, polymethylpentene and the like are preferable, and polypropylene is more preferable. Further, as the polyester resin, for example, polyethylene terephthalate or the like is preferable. By using at least one of polyethylene, polypropylene, polybutene, polymethylpentene, polyester and the like as the thermoplastic resin, the dispersibility of the inorganic material 2c can be improved. In particular, by using polypropylene, the dispersibility of the inorganic material 2c can be further improved.

The inorganic material 2c is preferably in a powder shape (powder shape). Further, the average particle diameter (mode diameter) of the inorganic material 2c is preferably in the range of 1 μm or more and 3 μm or less. If the average particle size of the inorganic material 2c is less than 1 μm, the cohesive force between the inorganic materials 2c may increase and the dispersibility in the thermoplastic resin may decrease. Further, if the average particle size of the inorganic material 2c exceeds 3 μm, the flatness of the surface of the base material layer 2 may decrease, and the thickness of the first anchor layer 3 and the second anchor layer 5 may become non-uniform. , Unevenness and chipping may occur. The maximum particle size of the inorganic material 2c is preferably 50 μm or less. If the maximum particle size of the inorganic material 2c exceeds 50 μm, the flatness of the surface of the base material layer 2 is lowered, and the thickness of the first anchor layer 3 and the second anchor layer 5 may be uneven or uneven. And chips may occur.
As described above, by setting the average particle size and the maximum particle size of the inorganic material 2c within the above-mentioned ranges, the dispersibility of the inorganic material 2c with respect to the thermoplastic resin is improved, and the surface of the base material layer 2 is covered. On the other hand, it becomes possible to maintain flatness.

The content of the inorganic material 2c may be in the range of 15% by mass or more and 90% by mass or less, and more preferably in the range of 20% by mass or more and 80% by mass or less with respect to the mass of the base material layer 2. , 60% by mass or more and 80% by mass or less is more preferable. When the content of the inorganic material 2c is less than 15% by mass, the proportion of the thermoplastic resin is relatively large, so that it tends to be difficult to obtain nonflammability, flame retardancy, weather resistance, abrasion resistance, and dimensional stability. There is. Further, when the surface of the base material layer 2 is scratched with a Hoffman scratch tester, there is a possibility that the surface is scratched to a visible degree, that is, sufficient surface hardness cannot be obtained.

On the other hand, when the content of the inorganic material 2c exceeds 90% by mass with respect to the mass of the base material layer 2, the proportion of the thermoplastic resin becomes relatively small. Therefore, when the first anchor layer 3 and the second anchor layer 5 are formed, so-called “powder blowing” may occur on the surface of the base material layer 2. Here, "powder blowing" indicates a state in which the inorganic material 2c contained in the base material layer 2 floats on the surface of the base material layer 2. Further, when the decorative layer 4 is formed, the inorganic material 2c that emerges from the base material layer 2 makes it difficult for the ink to be laminated, which may reduce printability. Further, the sheet in which the flexibility is reduced and at least one of the first anchor layer 3, the second anchor layer 5 and the decorative layer 4 is formed is laminated on the wood-based base material and the stone-based base material in the form of rolls or single leaves. When doing so, laminating tends to be difficult and laminating suitability tends to decrease. Further, when the sheet forming at least one of the first anchor layer 3, the second anchor layer 5, and the decorative layer 4 is bent and reopened, cracks and the fall of the inorganic material 2c may occur in the bent portion. There is. Further, after the cellophane tape is pressure-bonded to the surface of the sheet on which the decorative layer 4 is formed, the cellophane tape is strongly peeled off, causing peeling between the decorative layer 4 or the first anchor layer 3 and the decorative layer 4, and the ink adhesion is lowered. there is a possibility.

As described above, by setting the content of the inorganic material 2c within the above-mentioned range with respect to the mass of the base material layer 2, the ratio of the thermoplastic resin to the inorganic material 2c of the specific agent becomes appropriate. Therefore, it is possible to reduce the occurrence of powder blowing while obtaining nonflammability or flame retardancy. In addition to this, it is possible to improve printability and laminating suitability, reduce cracks generated in the bent portion of the sheet and drop of the inorganic material 2c, and further obtain sufficient surface hardness. , It is possible to improve the ink adhesion. In addition, it is possible to improve mechanical properties such as flame retardancy, weather resistance, abrasion resistance and flexibility.

As the inorganic material, for example, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, kaolin, silica, pearlite, calcium sulfate, barium sulfate, calcined alumina, calcium silicate, talc, mica and the like can be used. is there. Further, for example, zirconium compounds such as silica (particularly hollow silica), alumina, antimony trioxide, antimony soda, zircon silicate, zircon oxide, magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, borosand, zinc borate, etc. Antimony trioxide and silica complex such as antimony trioxide or antimony dimolybate and aluminum hydroxide complex, antimony trioxide and zinc flower complex, silicic acid of zirconium, zirconium compound and antimony trioxide complex, and their At least one kind such as salt can be used. In particular, calcium carbonate and calcium carbonate can easily control the particle size and compatibility with the thermoplastic resin by the manufacturing method, and the material cost is low, so that the resin sheet 10 can be made cheaper. It is also suitable from the viewpoint. Further, the above-mentioned inorganic materials may be used alone or in combination of two or more.

In this embodiment, as an example, a case where the inorganic material is calcium carbonate will be described. This is because calcium carbonate, talc, aluminum hydroxide and magnesium hydroxide are preferable as the inorganic material from the viewpoint of machinability and economy, and calcium carbonate is particularly preferable. The calcium carbonate is not particularly limited, and precipitated calcium carbonate, heavy calcium carbonate, light calcium carbonate and the like can be used.
The average particle size of calcium carbonate is preferably in the range of 1 [μm] or more and 3 [μm] or less.

Further, the total content of the thermoplastic resin and the inorganic material 2c is preferably in the range of 90% by mass or more and 100% by mass or less with respect to the mass of the flame-retardant sheet 1. If the total content of the thermoplastic resin and the inorganic material 2c is less than 90% by mass with respect to the mass of the flame-retardant sheet 1, sufficient non-flammability or sufficient flame-retardant property may not be obtained. In addition, printability and laminating suitability may be reduced, and cracks may occur in the bent portion of the sheet.
As described above, by setting the total content of the thermoplastic resin and the inorganic material 2c within the above-mentioned numerical range, printability and laminating suitability are improved while obtaining sufficient nonflammability or sufficient flame retardancy. It is possible to reduce cracks generated in the bent portion of the sheet.

When the total content of the thermoplastic resin and the inorganic material 2c is 100% by mass with respect to the mass of the flame-retardant sheet 1, the content of the thermoplastic resin is 10% by mass or more and 85% by mass or less. It is preferable that the content of the inorganic material 2c is within the range of 15% by mass or more and 90% by mass or less. Further, it is more preferable that the content of the thermoplastic resin is in the range of 20% by mass or more and 80% by mass or less, and the content of the inorganic material 2c is in the range of 20% by mass or more and 80% by mass or less. Further, it is more preferable that the content of the thermoplastic resin is in the range of 20% by mass or more and 40% by mass or less, and the content of the inorganic material 2c is in the range of 60% by mass or more and 80% by mass or less. When the total content of the thermoplastic resin and the inorganic material 2c is within the above-mentioned numerical range, sufficient nonflammability or sufficient flame retardancy is surely obtained, printability and laminating suitability are surely improved, and , It is possible to surely reduce the cracks generated in the bent portion of the sheet.

The thickness of the base material layer 2 is preferably in the range of 50 μm or more and 250 μm or less, and more preferably in the range of 70 μm or more and 200 μm or less. If the thickness of the base material layer 2 is less than 50 μm, the laminating suitability tends to decrease. Further, if the thickness of the base material layer 2 exceeds 250 μm, cracks may occur in the bent portion of the sheet. Therefore, if the thickness of the base material layer 2 is within the above-mentioned numerical range, it is possible to improve the laminating suitability and reduce the cracks generated in the bent portion of the sheet.

Further, the base material layer 2 is preferably a uniaxially stretched or biaxially stretched raw fabric layer. A uniaxially stretched or biaxially stretched raw material layer can enhance the versatility of the flame retardant sheet 1. By uniaxially stretching or biaxially stretching the thermoplastic resin mixed with the inorganic material 2c, a void 2d is formed around the inorganic material 2c. Further, it is preferable that the base material layer 2 is subjected to surface treatment such as corona treatment or plasma treatment before forming the first anchor layer 3 and the second anchor layer 5. By applying surface treatment such as corona treatment or plasma treatment to the base material layer 2, it is possible to improve the adhesiveness (adhesion) between the first anchor layer 3 and the second anchor layer 5 and the base material layer 2. It becomes. Further, the powder-blown inorganic material 2c (for example, calcium carbonate) may be removed in advance by brushing the base material layer 2 before forming the first anchor layer 3 and the second anchor layer 5.

(First anchor layer)
The first anchor layer 3 is laminated on one surface (front surface) of the base material layer 2, and is formed so as to cover the entire one surface (front surface) of the base material layer 2. .. As a result, the first anchor layer 3 can prevent the inorganic material 2c contained in the base material layer 2 from falling off. If the inorganic material 2c contained in the base material layer 2 falls off in the printing system, specifically, in the printing apparatus during printing or resin coating, the inside of the printing system may be contaminated. Further, when the inorganic material 2c contained in the base material layer 2 is powdered off, problems such as ink loss in which the ink is not partially printed may occur.
Further, the first anchor layer 3 also has a function of improving the adhesion between the base material layer 2 and the ink forming the pattern pattern layer 4a described later. In the configuration without the first anchor layer 3, the ink forming the pattern layer 4a may peel off without adhering to the base material layer 2.

Further, the first anchor layer 3 preferably contains a urethane resin containing vinyl salt vinegar or an acrylic resin containing vinyl salt vinegar. Here, "vinyl salt vinegar" means a copolymer of vinyl chloride and vinyl acetate. Further, as the urethane-based resin, for example, a two-component curable polyurethane-based adhesive containing a polyol component and an isocyanate component is preferable. As the polyol component, a polyester polyol, a polyester polyurethane polyol, a polyether polyol, a polyether polyurethane polyol, or the like can be used. Further, as the isocyanate component, diisocyanates such as TDI, MDI, HDI, PIDI, and XDI and modified products using these as starting materials can be used.

The content of the urethane resin containing vinyl salt vinegar or the acrylic resin containing vinyl salt vinegar in the first anchor layer 3 is, for example, 15% by mass or more 100% by mass in a dry state with respect to the mass of the first anchor layer 3. The range of mass% or less is preferable, the range of 80% by mass or more and 100% by mass or less is more preferable, and the range of 85% by mass or more and 95% by mass or less is further preferable. If the content of the urethane resin containing vinyl salt vinegar or the acrylic resin containing vinyl salt vinegar in the first anchor layer 3 is within the above numerical range, the layer between the first anchor layer 3 and the pattern layer 4a It is possible to form the first anchor layer 3 which is uniform and has no unevenness or chipping while maintaining sufficient strength. When the content of the urethane resin containing vinyl salt vinegar or the acrylic resin containing vinyl salt vinegar in the first anchor layer 3 is less than 15% by mass in the dry state with respect to the mass of the first anchor layer 3. The interlayer strength between the first anchor layer 3 and the pattern layer 4a may be insufficient. The content of the urethane resin containing vinyl salt vinegar or the acrylic resin containing vinyl salt vinegar in the first anchor layer 3 should be 100% by mass or less in a dry state with respect to the mass of the first anchor layer 3. For example, there is no problem in use, but if it exceeds 95% by mass, unevenness or chipping may occur in the first anchor layer 3. As the coating amount, it is appropriate that the solid content is in the range of about 0.5 [g / m ² ] or more and 3.5 [g / m ² ] or less.
The thickness of the first anchor layer 3 is preferably in the range of 0.5 μm or more and 20 μm or less, and more preferably in the range of 0.5 μm or more and 10 μm or less.

(Cosmetic layer)
The decorative layer 4 is laminated on the first anchor layer 3, and is formed so as to face one surface (front surface) of the base material layer 2 with the first anchor layer 3 in between. ..
Further, the decorative layer 4 includes a pattern layer 4a and a top coat layer 4b.

(Pattern pattern layer)
The pattern pattern layer 4a is laminated on the first anchor layer 3. Specifically, the pattern layer 4a is laminated on the upper surface of the first anchor layer 3 in FIG. 1.
The material of the pattern layer 4a is excellent in processability and does not generate harmful gas during combustion. Therefore, for example, saturated polyester, low density polyethylene (including linear low density polyethylene), medium density polyethylene, and high density. Polyethylene, homopolypropylene, ethylene α-olefin copolymer, polymethylpentene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, or It is possible to use a film-based base material made of a mixture of these. These materials may be in an unstretched state or in a uniaxial or biaxially stretched state, and the thickness is appropriately in the range of 25 μm or more and 125 μm or less. .. Further, as the material of the pattern layer 4a, for example, print paper for building materials (thin leaf paper for building materials), pure white paper, thin leaf paper in which synthetic resin is mixed to enhance interlayer strength, and opaque pigments such as titanium oxide are mixed. It is also possible to use a paper-based base material such as titanium paper.

The basis weight of the pattern layer 4a is, for example, within the range of 23 g / m ² or more and 100 g / m ² or less. These film-based base materials or paper-based base materials may be subjected to appropriate easy-adhesion treatment such as corona discharge treatment, plasma treatment, ozone treatment, etc. on necessary surfaces as needed.
Further, on the pattern pattern layer 4a, patterns such as wood grain pattern, stone grain pattern, cloth pattern, leather pattern, geometric pattern, characters, symbols, line art, various abstract patterns, etc. are printed by gravure printing method, offset printing method, etc. It is formed by using ink by a well-known printing method such as a silk screen printing method. Ink includes chlorinated polyethylene such as chlorinated polyethylene and chlorinated polypropylene, polyester, polyurethane containing isocyanate and polyol, polyacrylic, polyvinyl acetate, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, cellulose-based ink. It is possible to use one type or a mixture of two or more types of resin, polyamide resin, etc., and add pigments, solvents, various auxiliary agents, etc. to the ink, but considering environmental issues, polyester , Polyacryl containing isocyanate and polyol, polyvinyl chloride, cellulose-based resin, polyamide-based resin, and other non-chlorine vehicles mixed with one or more are suitable, and more preferably polyester, isocyanate and the like. One or a mixture of one or more of polyurethane, polyacrylic, polyamide-based resin, etc. containing polyol is used.

Moreover, it is preferable to contain titanium oxide as a white pigment. By containing titanium oxide, whiteness and hiding power are improved, and flame retardancy is also improved. The titanium oxide is not particularly limited, and examples thereof include anatase-type titanium oxide and rutile-type titanium oxide. Any titanium oxide may be used, but in particular, it has a flame retardant effect and weather resistance. From this point of view, it is preferable to use rutile-type titanium oxide. Further, when the flame-retardant sheet 1 is used in an application requiring antifouling property, it is preferable to use titanium oxide having a photocatalytic effect.
The content of titanium oxide is preferably 1 part by mass or more and 20 parts by mass or less, and more preferably 2 parts by mass or more and 7 parts by mass or less with respect to 100 parts by mass of the vehicle. If the blending amount of titanium oxide is less than 1 part by mass, it may not be possible to sufficiently obtain whiteness, hiding power and flame retardant effect. Further, when the blending amount of titanium oxide exceeds 20 parts by mass, whiteness, hiding power and flame retardant effect can be sufficiently obtained, but there is a possibility that molding processability and flexibility may be lowered.

(Top coat layer)
The top coat layer 4b is laminated on the pattern layer 4a. Specifically, the top coat layer 4b is laminated on the upper surface of the pattern layer 4a in FIG. 1.
Further, the top coat layer 4b is provided to protect the pattern layer 4a and to impart surface physical properties such as stain resistance, scratch resistance, and abrasion resistance required for the flame retardant sheet 1.

Examples of the resin forming the top coat layer 4b include a two-component curable polyurethane resin containing a polyol component and an isocyanate component, or a group consisting of a fluororesin, an acrylic resin, and an ethylene-vinyl alcohol-vinyl acetate copolymer. It is preferable to use a resin consisting of at least one selected from the above. As the polyol component, an acrylic polyol, a polyester polyol, a polyether polyol, or the like can be used. As the isocyanate component, either a non-yellowing type or a yellowing type can be used, but the non-yellowing type is preferable in terms of light resistance and flexibility of the resin coating film. Specifically, for example, it is desirable to use hexamethylene diisocyanate, isophorone diisocyanate, or the like. Further, since xylylene diisocyanate has little yellowing, it can be suitably used depending on the application.

When a patterned glossy resin layer is provided on the top coat layer 4b, the resin used for the top coat layer 4b needs to have a recoating property (recoating property). When a curable resin having a property of losing recoatability when completely cured is used, it is necessary to provide a gloss resin layer before the topcoat layer 4b is completely cured. For that purpose, when a curable resin that is liquid at room temperature is used, such as a two-component curable polyurethane resin, the top coat layer 4b is made into a non-fluid half before forming a patterned glossy resin layer. It is necessary to put it in a cured state, but if a thermosetting resin that becomes dry to the touch due to evaporation of the solvent is used, the semi-curing step as described above becomes unnecessary, and the top coat layer 4b and the gloss are removed. It is suitable because the adhesion with the resin layer is stable.

Further, as a method of forming the top coat layer 4b with the two-component curable polyurethane resin, for example, the viscosity of the two-component curable polyurethane resin is adjusted to a coatable viscosity, and a well-known method such as a gravure coating method or a roll coating method is used. It can be formed by coating by a coating method. As the coating amount, it is appropriate that the solid content is in the range of approximately 3 g / m ² or more and 15 g / m ² or less.
Further, a primer layer for ink and a primer layer for the top coat layer are provided between the pattern layer 4a and the top coat layer 4b, and it is possible to improve the adhesive strength between the layers. These primer layers are formed by a well-known coating method such as a gravure printing method or a roll coating method using a two-component curable polyurethane adhesive containing a polyol component and an isocyanate component used for the first anchor layer 3. It's good. The amount of the primer layer for ink and the primer layer for topcoat layer after drying is in the range of 0.1 g / m ² or more and 5.0 g / m ² or less, preferably 0.5 g / m ² or more. It is within the range of 1.0 g / m ² or less.

An ultraviolet absorber and a light stabilizer may be appropriately added to the top coat layer 4b in order to improve the weather resistance of the flame retardant sheet 1. Further, in order to impart various functions, functional additives such as an antibacterial agent, an antifungal agent, and a matting agent for adjusting gloss may be added. As the matting agent, for example, inorganic powder such as silica or calcium carbonate, glass beads, synthetic resin beads and the like are used, and those having an average particle size of 0.5 μm or more and 5 μm or less are used. The amount of the matting agent added is arbitrary depending on the degree of matte feeling desired in terms of design, but it is usually preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the resin. Since the coating composition for forming the top coat layer 4b contains an inorganic abrasion resistant agent having a large particle size, a high specific gravity and easy to settle, prevention of sedimentation so that the precipitation of the inorganic abrasion resistant agent does not make it difficult to continue the coating work. It is preferable to add an agent.

Further, an inorganic abrasion resistant agent may be added to impart abrasion resistance. The inorganic abrasion resistant agent is, for example, a powder or granular material of a hard inorganic compound such as alumina or silicon carbide, and preferably has an average particle size in the range of 5 μm or more and 50 μm or less. The amount added is preferably 2 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the resin. The shape of the inorganic abrasion resistant agent may be any of irregular shape, scaly shape, spherical shape, polyhedral shape and the like, but the scaly shape, spherical shape, polyhedral shape and the like are preferable because of their high wear resistance effect.
It is also recommended to add a silane coupling agent to improve the retention of the inorganic abrasion resistant agent so that the inorganic abrasion resistant agent protruding from the surface of the top coat layer 4b does not easily come off. The thickness of the topcoat layer 4b is not particularly limited, but if it is too thin, the inorganic abrasion resistant agent cannot be sufficiently retained, and if it is too thick, the flexibility is lowered and the topcoat layer 4b is easily cracked. It is desirable that the range is 50 μm or less.

(Second anchor layer)
The second anchor layer 5 is laminated on the other surface (back surface) of the base material layer 2, and is formed so as to cover the entire other surface (back surface) of the base material layer 2. As a result, the second anchor layer 5 prevents the inorganic material 2c contained in the base material layer 2 from falling off. If the inorganic material 2c contained in the base material layer 2 falls off in the printing system, specifically, in the printing apparatus during printing or resin coating, the inside of the printing system may be contaminated. Further, if the inorganic material 2c contained in the base material layer 2 is powdered off, problems such as ink loss may occur. Further, the second anchor layer 5 also has a function of improving the adhesion between the base material layer 2 and the primer layer 6. When the second anchor layer 5 is not provided, the coating liquid forming the primer layer 6 may peel off without adhering to the base material layer 2.
The second anchor layer 5 is formed by using the same materials and methods as those of the first anchor layer 3.

(Primer layer)
The primer layer 6 is laminated on the second anchor layer 5, and faces the back surface of the base material layer 2 with the second anchor layer 5 in between.
As the material of the primer layer 6, for example, nitrocellulose as a binder, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, etc. alone or each modified product are appropriately selected. It can be used. These are aqueous, solvent-based, emulsion type, etc., regardless of their form. In addition, the curing method can be appropriately selected from a one-component type that cures independently, a two-component type that uses a curing agent in combination with the main agent, and a type that cures by irradiation with ultraviolet rays or electron beams. is there. As a general curing method, a two-component type that cures by combining an isocyanate-based curing agent with a urethane-based main agent is used, and the method using this two-component type is workability, price, and resin. It is suitable from the viewpoint of its own cohesive force. In addition to the binders described above, colorants such as pigments and dyes, extender pigments, solvents, various additives and the like are added.
In particular, since the primer layer 6 is located on the backmost surface of the flame-retardant sheet 1, considering that the flame-retardant sheet 1 is wound as a continuous plastic film (web-like), the films adhere to each other and slip. Even if an inorganic filler such as silica, alumina, magnesia, titanium oxide, or barium sulfate is added in order to prevent blocking such as difficulty in peeling or peeling off, and to improve adhesion with the adhesive. Good. The thickness of the primer layer 6 is preferably in the range of 0.1 μm or more and 3.0 μm or less, for example.

(Manufacturing method of flame-retardant sheet 1)
Hereinafter, a method for manufacturing the flame-retardant sheet 1 of the embodiment will be described with reference to FIG.
First, the inorganic material 2c is mixed with the thermoplastic resin, and the mixed thermoplastic resin is uniaxially or biaxially stretched to form a porous thermoplastic resin film 2a having pores 2b at the position of the inorganic material 2c. , The base material layer 2 is formed. At that time, by uniaxially stretching or biaxially stretching the thermoplastic resin, the pores 2b are expanded in the stretching direction, and voids 2d are formed around the inorganic material 2c.
Subsequently, one surface (front surface) of the base material layer 2 is coated with a resin or the like for forming the first anchor layer 3 to form the first anchor layer 3. Subsequently, an ink for forming the pattern pattern layer 4a is applied to the surface of the first anchor layer 3 opposite to the surface facing the base material layer 2 to form the pattern pattern layer 4a. Subsequently, a resin or the like for forming the top coat layer 4b is applied to the surface of the pattern layer 4a opposite to the surface facing the first anchor layer 3 to form the top coat layer 4b.

Subsequently, a resin or the like for forming the second anchor layer 5 is applied to the other surface (back surface) of the base material layer 2 to form the second anchor layer 5. Subsequently, a resin for forming the primer layer 6 is applied to the surface of the second anchor layer 5 opposite to the surface facing the base material layer 2 to form the primer layer 6.
The flame-retardant sheet 1 according to the embodiment of the present invention is manufactured by such a procedure.
The second anchor layer 5 may be formed at the same time as the first anchor layer 3. Further, the primer layer 6 may be formed before forming the pattern layer 4a and the top coat layer 4b. In this case, the second anchor layer 5 may be formed before the first anchor layer 3.

As described above, in the flame-retardant sheet 1 according to the embodiment of the present invention, the base material layer 2 is such that the porous thermoplastic resin film 2a having pores 2b and the voids 2d remain in the pores 2b. Is provided with an inorganic material 2c arranged in the pores 2b. Therefore, since the base material layer 2 has the inorganic material 2c and the voids 2d, it is possible to provide the flame-retardant sheet 1 having excellent flame retardancy and heat insulating properties.

(Modification example)
In the above embodiment, the example in which the decorative layer 4 is laminated on the first anchor layer 3 is shown, but other configurations can also be adopted. For example, an adhesive layer for improving the adhesiveness (adhesion) between the first anchor layer 3 and the decorative layer 4 may be formed between the first anchor layer 3 and the decorative layer 4.
Further, in the above embodiment, the example in which the primer layer 6 is laminated on the second anchor layer 5 is shown, but other configurations can also be used. For example, an adhesive layer for improving the adhesiveness between the second anchor layer 5 and the primer layer 6 may be formed between the second anchor layer 5 and the primer layer 6. As the material of the adhesive layer, for example, a material that exhibits adhesiveness when heated can be used. Examples of the material that exhibits adhesiveness when heated include chlorinated polyolefin resin, polyurethane resin, epoxy resin, acrylic resin, vinyl resin, vinyl acetate resin, polyester resin, ethylene-vinyl acetate copolymer resin, and the like. Examples of the material include an acrylic-vinyl acetate copolymer resin, a polyamide resin, an ionomer resin and the like as main components.

Hereinafter, the flame-retardant sheet of the example and the flame-retardant sheet of the comparative example will be described.
(Example 1)
First, a biaxially stretched polyethylene terephthalate film (porous thermoplastic resin film 2a) having a thickness of 50 μm was prepared as the base material layer 2. Calcium carbonate (inorganic material 2c) was arranged in the pores 2b of the base material layer 2 so that the voids 2d remained in the pores 2b. Subsequently, a two-component curable polyurethane adhesive is applied to one surface (front surface) of the base material layer 2 by a gravure printing method so that the mass after drying is 0.5 g / m ^2. , The first anchor layer 3 was formed. Subsequently, a pattern layer 4a was formed on the surface of the first anchor layer 3 by a gravure printing method using an acrylic ink. Subsequently, a two-component curable urethane resin was applied to the surface of the pattern layer 4a by a roll coating method to form a top coat layer 4b having a mass of 10 g / m ² after drying.
Subsequently, a two-component curable polyurethane adhesive is applied to the other surface (back surface) of the base material layer 2 by a gravure printing method so that the mass after drying is 0.5 g / m ² . The anchor layer 5 was formed. Further, a two-component curable polyurethane adhesive was applied to the surface of the second anchor layer 5 by a gravure printing method so that the mass after drying was 0.5 g / m ² , to form the primer layer 6. As a result, the flame-retardant sheet 1 of Example 1 was produced.

(Comparative Example 1)
In Comparative Example 1, an epoxy resin film (porous thermosetting resin film) was used instead of the biaxially stretched polyethylene terephthalate film (porous thermoplastic resin film 2a). A flame-retardant sheet 1 of Comparative Example 1 was produced in the same manner as in Example 1 except for the above.
(Comparative Example 2)
In Comparative Example 2, urethane beads and spherical organic fine particles (organic material) were used instead of calcium carbonate (inorganic material 2c). A flame-retardant sheet 1 of Comparative Example 2 was produced in the same manner as in Example 1 except for the above.
(Comparative Example 3)
In Comparative Example 3, urethane beads and spherical organic fine particles (organic material) were used instead of calcium carbonate (inorganic material 2c). Further, instead of the biaxially stretched polyethylene terephthalate film (porous thermoplastic resin film 2a), an epoxy resin film (porous thermosetting resin film) was used. A flame-retardant sheet 1 of Comparative Example 3 was produced in the same manner as in Example 1 except for the above.
(Comparative Example 4)
In Comparative Example 4, a polyethylene terephthalate film (thermoplastic resin film 2a) in which no voids 2d remained in the pores 2b was used as the base material layer 2. The thermoplastic resin film 2a was formed as a film without stretching the thermoplastic resin to which the inorganic material 2c was added. A flame-retardant sheet 1 of Comparative Example 3 was produced in the same manner as in Example 1 except for the above.

(Performance evaluation)
(Flame retardant test)
In the flame retardancy test, a test piece (100 mm × 100 mm × 3 mm thick) was irradiated with a heat ray of 50 kW / m ² by a cone calorimeter according to ASTM E 1354, and the test piece was burned. The maximum heat generation rate was determined by measuring the time from the start of heating to the ignition of the test piece. Then, the case where the maximum heat generation rate was 350 kW / m ² or less was regarded as a pass "◯", and the case where the maximum heat generation rate was larger than 350 kW / m ² was regarded as a fail "x".
(Insulation test)
In the heat insulation test, a temperature sensor was installed inside a 50 x 50 x 50 cm box, and the flame retardant sheet 1 was attached to the inner surface of the glass plate provided on one side of the box, and the box was placed from the outside of the box. An infrared lamp was irradiated to the inside via a glass plate, and the temperature rise inside the box was measured before and after 1 hour of irradiation. Then, the case where the temperature rise before and after 1 hour irradiation was less than 16 ° C. was regarded as a pass "◯", and the case where the temperature rise was 16 ° C. or higher was regarded as a fail "x".
(Evaluation results)
The evaluation results are shown in Table 1.

As shown in Table 1 above, the flame-retardant sheet 1 of Example 1 passed both the “flame-retardant test” and the “insulation test” with “◯”. On the other hand, in the flame-retardant sheet 1 of Comparative Examples 1 to 4, at least one of the "flame-retardant test" and the "adhesion test" was rejected as "x".
Therefore, it was confirmed that the flame-retardant sheet 1 of Example 1 is excellent in both flame-retardant property and heat-insulating property, unlike the flame-retardant sheet 1 of Comparative Examples 1 to 4.

1 ... Flame-retardant sheet, 2 ... Base material layer, 2a ... Thermoplastic resin film, 2b ... Pore, 2c ... Inorganic material, 2d ... Void, 3 ... First anchor layer, 4 ... Decorative layer, 4a ... Pattern layer 4b ... Top coat layer, 5 ... Second anchor layer, 6 ... Primer layer

Claims (5)

A flame-retardant sheet in which a base material layer, an anchor layer, and a decorative layer are laminated in this order.
The base material layer is flame-retardant, comprising: a porous thermoplastic resin film having pores, and an inorganic material arranged in the pores so that voids remain in the pores. Sheet. The inorganic materials include antimony trioxide, antimony soda, zircon silicate, zircon oxide, magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, borosand, zinc borate, calcium carbonate, molybdenum trioxide or antimony dimolybate and water. It is characterized by containing at least one of aluminum oxide complex, antimony trioxide and silica complex, antimony trioxide and zinc flower complex, silicic acid of zirconium, and zirconium compound and antimony trioxide complex, and salts thereof. The flame-retardant sheet according to claim 1. The thermoplastic resin constituting the thermoplastic resin film is an ethylene homopolymer, a propylene homopolymer, an ethylene and / or a copolymer of propylene and another α-olefin copolymerizable therewith, or ethylene-acrylic acid. The flame-retardant sheet according to claim 1 or 2, wherein the flame-retardant sheet is at least one selected from the group consisting of an ethyl copolymer and an ethylene-vinyl acetate copolymer, or a polyester-based resin. According to claims 1 to 3, in a combustion test based on ASTM E 1354, the maximum heat generation rate when heated and burned for 30 minutes under radiant heating conditions of 50 kW / m ² is 350 kW / m ² or less. The flame-retardant sheet according to any one item. From claim 1, the outermost layer of the decorative layer is provided with a top coat layer composed of at least one selected from the group consisting of a fluororesin, an acrylic resin and an ethylene-vinyl alcohol-vinyl acetate copolymer. The flame-retardant sheet according to any one of 4.

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