Flame-retardant metal-resin composite material

Abstract

A flame-retardant metal-resin composite material according to the present disclosure is a metal-resin composite material in which metal layers are laminated on both surfaces of a core material layer containing a resin. The core material layer contains a metal hydroxide, a resin having a specific polar group, and a flame retardant containing at least one compound selected from the group consisting of an inorganic polyphosphate compound, an inorganic phosphite compound, an inorganic phosphinate compound, an inorganic metaphosphate compound, a melamine compound, and a triazine compound.

Description

Flame-retardant metal-resin composite

[0001] The present invention relates to a flame-retardant metal-resin composite material, and more particularly to a flame-retardant metal-resin composite material suitable for exterior building materials, which is constructed by using a resin layer containing a metal hydroxide as a core sheet and bonding metal sheets to both sides of the core sheet.

[0002] A flame-retardant metal-resin composite material, which is constructed by bonding metal sheets to both sides of a core sheet made of a resin layer containing an inorganic filler, is a material that combines many characteristics, such as light weight, corrosion resistance, heat insulation, flame retardancy, weather resistance, a beautiful surface, and workability similar to that of metal. However, the above composite material is not fully satisfactory as an exterior building material, such as an exterior wall material for a building.

[0003] Flame retardancy is a desirable physical property required for exterior building materials, and progress is being made in the development of flame-retardant metal-resin composite materials with improved flame retardancy.

[0004] For example, Patent Document 1 discloses a flame-retardant metal resin composite material in which metal layers are laminated on both sides of a core layer containing a resin, the core layer containing a metal hydroxide and a resin, the combustion heat value of the core layer being 2.0 MJ / kg or less, and the face material peel strength of the metal resin composite being 2.4 N / mm or more.

[0005] International Publication No. 2019 / 159929

[0006] Flame retardancy evaluation tests for flame retardant metal-resin composites for exterior building materials, etc., vary from country to country. The flame retardant metal-resin composite disclosed in Patent Document 1 may not meet the flame retardancy required by the flame retardancy evaluation tests of each country, and further development of flame retardant metal-resin composites with improved flame retardancy is desired.

[0007] One aspect of the present invention is to provide a flame-retardant metal-resin composite with improved flame retardancy.

[0008] In order to solve the above problems, the present inventors have conducted extensive research. As a result, they have independently developed a test method that can evaluate the flame retardancy required by flame retardancy evaluation tests in various countries. They have also found that a flame-retardant metal-resin composite containing a specific flame retardant satisfies the flame retardancy standards in the test method independently developed by the present inventors, and have thus completed the present invention.

[0009] [1] A flame-retardant metal resin composite material in which metal layers are laminated on both sides of a core layer containing a resin, wherein the core layer contains: a metal hydroxide; a resin having at least one polar group selected from the group consisting of a hydroxyl group, a carboxyl group, an aldehyde group, an amino group, a glycidyl group, and a ketone group; and a flame retardant containing at least one selected from the group consisting of an inorganic polyphosphate compound, an inorganic phosphite compound, an inorganic phosphinate compound, an inorganic metaphosphate compound, a melamine compound, and a triazine compound. [2] The flame-retardant metal resin composite according to [1], wherein, in the following combustion test, the core layer does not ignite for 1 second or more within 120 seconds after being placed in an electric furnace and within 120 seconds after being removed from the electric furnace: [Combustion test] A core layer test piece measuring 38 mm in length, 38 mm in width, and 3 mm in height is placed in an electric furnace with a heater output of 500 W, furnace interior dimensions of 90 mm x 110 mm x 70 mm, and the furnace interior controlled at 800°C, so that the 38 mm x 38 mm surface of the core layer test piece is approximately perpendicular to the bottom surface of the electric furnace. [3] The flame-retardant metal resin composite according to [1] or [2], wherein the face material peel strength of the metal resin composite is 2.4 N / mm or more. [4] The flame-retardant metal resin composite according to any one of [1] to [3], wherein the resin is at least one resin selected from the group consisting of polyvinyl alcohol-based resins, polyamide-based resins, modified polyolefin-based resins, olefin-based copolymers, acrylic resins, polyurethane-based resins, and epoxy-based resins. [5] The flame-retardant metal resin composite according to any one of [1] to [4], further comprising an adhesive layer between the core layer and the metal layer, the adhesive layer containing a resin having at least one polar group selected from the group consisting of a hydroxyl group, a carboxyl group, an aldehyde group, an amino group, a glycidyl group, and a ketone group. [6] The flame-retardant metal resin composite according to [5], wherein the resin contained in the adhesive layer is at least one resin selected from the group consisting of polyvinyl alcohol-based resins, polyamide-based resins, modified polyolefin-based resins, olefin-based copolymers, acrylic resins, polyurethane-based resins, and epoxy-based resins.[7] The flame-retardant metal resin composite according to any one of [1] to [6], which contains 1 to 15 parts by mass of the flame retardant per 100 parts by mass of the core layer. [8] The flame-retardant metal resin composite according to any one of [1] to [7], which contains 1 to 10 parts by mass of the resin per 100 parts by mass of the core layer. [9] The flame-retardant metal resin composite according to any one of [1] to [8], which contains 30 to 95 parts by mass of the metal hydroxide per 100 parts by mass of the core layer.

[10] The flame-retardant metal resin composite according to any one of [1] to [9], which further contains a layer made of nonwoven fabric.

[0010] According to one aspect of the present invention, a flame-retardant metal-resin composite material having improved flame retardancy can be provided.

[0011] One embodiment of the present invention will be described in detail below, but the present invention is not limited to the following embodiments as long as it does not deviate from the purpose. In this specification, the term "to" includes the upper and lower limits. Furthermore, for each preferred range, the upper and lower limits can be used in any combination.

[0012] A flame-retardant metal-resin composite according to one embodiment of the present invention is a metal-resin composite in which metal layers are laminated on both sides of a resin-containing core layer. In this specification, "metal layers are laminated on both sides of the core layer" refers to at least two metal layers sandwiching the core layer, and another layer may be provided between the core layer and the metal layer. Examples of the other layer include an adhesive layer, which will be described later.

[0013] <Core Layer> The core layer of the flame-retardant metal-resin composite according to one embodiment of the present invention contains at least a resin, a metal hydroxide, and a flame retardant. Hereinafter, the resin contained in the core layer may be referred to as a core resin.

[0014] [Core Resin] The core resin contained in the flame-retardant metal-resin composite according to one embodiment of the present invention is a resin having at least one polar group selected from the group consisting of a hydroxyl group, a carboxyl group, an aldehyde group, an amino group, a glycidyl group, and a ketone group. The core resin has a polar group, which enhances its interaction with the metal hydroxide. One or more types of core resins can be used.

[0015] Examples of the resin having a polar group include polyvinyl alcohol resins, polyamide resins, modified polyolefin resins, olefin copolymers, acrylic resins, polyurethane resins, and epoxy resins. These resins can be used alone or in combination. Among these, polyvinyl alcohol resins, polyamide resins, and olefin copolymers are preferred because of their excellent inorganic filler loading properties, and polyvinyl alcohol resins are more preferred.

[0016] Examples of polyvinyl alcohol resins include polyvinyl alcohol resins, modified polyvinyl alcohol resins containing 1 to 50 mol % of α-olefin units having 4 or less carbon atoms, and polyvinyl acetal resins (such as polyvinyl butyral resins).

[0017] In order to further improve the flame retardancy of the flame-retardant metal-resin composite, the polyvinyl alcohol resin is preferably a modified polyvinyl alcohol resin or a polyvinyl acetal resin (such as a polyvinyl butyral resin) containing 1 to 50 mol% of an α-olefin unit having 4 or less carbon atoms, and more preferably a polyvinyl butyral resin (hereinafter sometimes referred to as PVB).

[0018] Examples of polyamide resins include aliphatic polyamides such as polyamide 6, polyamide 66, polyamide 612, polyamide 11, polyamide 12, and polyamide 1010; and semi-aromatic polyamides such as polyamide 4T (a copolymer of 1,4-butanediamine and terephthalic acid), polyamide 6T (a copolymer of 1,6-hexanediamine and terephthalic acid), polyamide MXD6 (a copolymer of meta-xylylenediamine and adipic acid), polyamide 6I (a copolymer of 1,6-hexanediamine and isophthalic acid), and polyamide 9T (a copolymer of 1,9-nonanediamine and terephthalic acid).

[0019] Examples of modified polyolefin resins include unsaturated carboxylic acid graft-modified polyolefin resins such as maleic anhydride graft copolymers of polyethylene or maleic anhydride graft copolymers of ethylene-propylene copolymers, and (meth)acrylic acid graft-modified polyolefin resins such as acrylic acid graft copolymers of polyethylene.

[0020] Examples of olefin copolymers include ethylene copolymers such as ethylene-(meth)acrylic acid (ester) copolymer, ethylene-vinyl acetate copolymer, ethylene-glycidyl acrylate copolymer, and ethylene-maleic anhydride copolymer.

[0021] Examples of acrylic resins include resins that have at least a (meth)acrylic acid (ester) unit as a constituent unit, and may have a monomer unit such as styrene, acrylonitrile, methyl vinyl ketone, vinyl acetate, methallyl alcohol, allyl alcohol, 2-hydroxymethyl-1-butene, N-vinylpyrrolidone, or N-vinylcarbazole as a constituent unit other than the (meth)acrylic acid (ester) monomer.

[0022] Examples of polyurethane resins include resins in which polyurethane bonds are formed by polyaddition of a polyol component such as alkylene glycol or polyester polyol with a diisocyanate component such as aromatic diisocyanate, aliphatic diisocyanate, or alicyclic diisocyanate.

[0023] Examples of epoxy resins include alicyclic epoxy resins having a skeleton derived from an alicyclic compound, epoxy resins having a glycidyl ether group, and epoxy resins having an aromatic group.

[0024] When the core resin is an ethylene-based copolymer such as an ethylene-(meth)acrylic acid (ester) copolymer or an ethylene-vinyl acetate copolymer, the content of structural units other than ethylene (for example, (meth)acrylic acid (ester) units or vinyl acetate units) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 17.5% by mass or more, and particularly preferably 20% by mass or more. There is no upper limit to the content of structural units other than ethylene, but it is usually 90% by mass or less, preferably 80% by mass or less, and more preferably 70% by mass or less.

[0025] When the core resin is a polyvinyl alcohol-based resin, the hydroxyl group mass concentration (mass % of vinyl alcohol units in the resin) of the polyvinyl alcohol-based resin is preferably 10 to 40 mass %, and in order to obtain a multilayer structure having excellent interlayer adhesive strength, it is more preferably 15 to 40 mass %, and even more preferably 15 to 25 mass % (for example, 15, 20, or 25 mass %).

[0026] The hydroxyl group mass concentration of a polyvinyl alcohol resin can be measured according to JIS K6728 "Test Method for Polyvinyl Butyral." For example, a certain amount of polyvinyl alcohol resin is weighed, and the hydroxyl groups in the polyvinyl alcohol resin are acetylated with a mixed solution of acetic anhydride and pyrimidine, followed by titration with a sodium hydroxide solution. The hydroxyl group mass concentration can be calculated by multiplying the number of moles of sodium hydroxide consumed by the molecular weight of the hydroxyl group-containing unit.

[0027] The core resin may be modified by reacting it with a modifying agent such as an unsaturated carboxylic acid.

[0028] The combustion heat value of the core resin is not particularly limited, but is preferably 40 MJ / kg or less, more preferably 38 MJ / kg or less, and even more preferably 35 MJ / kg or less. The combustion heat value is measured using a method in accordance with the test method of ISO 1716 (2018 edition). The method in accordance with the test method of ISO 1716 (2018 edition) is a method using a bomb-type adiabatic calorimeter or an automatic bomb-type calorimeter.

[0029] The tensile strength of the core resin is not particularly limited, but is preferably 30 MPa or more, more preferably 35 MPa or more, and even more preferably 40 MPa or more. A tensile strength of 30 MPa or more is preferable in that it strengthens the entanglement with the main chain of the resin contained in the adhesive layer described below, thereby increasing the peel strength of the face material of the composite. The tensile strength is measured using the plastics - tensile properties test method in accordance with the test method of ISO 527-1 (2019 edition).

[0030] The melt viscosity of the core resin is not particularly limited, but is preferably 3,000 Pa s or less, more preferably 2,000 Pa s or less, and even more preferably 1,000 Pa s or less. There is no particular limit to the lower limit of the melt viscosity of the core resin, but it is usually 10 Pa s or more, preferably 30 Pa s or more, and more preferably 50 Pa s or more. If the melt viscosity of the core resin is 3,000 Pa s or less, the resin is more likely to be present at the interface between the adhesive layer and the core layer (described later) during heat molding in the manufacturing process, improving the adhesive strength between the core layer and the metal layer. The melt viscosity range of the core resin is preferably 30 to 3,000 Pa·s, more preferably 30 to 2,000 Pa·s, and even more preferably 50 to 1,000 Pa·s (for example, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1,000 Pa·s).

[0031] The melt viscosity is a value at a temperature of 200 ° C. and a shear rate of 100 [1 / sec], and is measured by a plastic flow test method using a plastic capillary rheometer and a slit die rheometer in accordance with the test method of ISO 11443 (2021 edition).

[0032] A preferred core resin is one having a combustion heat value of 40 MJ / kg or less, a tensile strength of 30 MPa or more, and a melt viscosity of 3,000 Pa s or less. By setting the combustion heat value, tensile strength, and melt viscosity of the core resin within the above ranges, the flame retardancy and peel strength of the composite can be increased even if the amount of resin contained in the core layer is small.

[0033] The weight average molecular weight (Mw) of the core resin is 5.0 × 10 ３ More preferably, 1.0 × 10 ４More preferably, 2.0 × 10 ４ The upper limit of the weight average molecular weight of the core resin is not limited, but it is usually 1.0 × 10 ５ or less, preferably 8.0 × 10 ４ The weight average molecular weight of the core resin is preferably in the range of 5.0×10 ３ ~8.0 x 10 ４ , more preferably 1.0 × 10 ４ ~8.0 x 10 ４ , more preferably 2.0 × 10 ４ ~8.0 x 10 ４ (For example, 2.0 × 10 ４ , 3.0 × 10 ４ , 4.0 × 10 ４ , 5.0 × 10 ４ , 6.0 × 10 ４ , 7.0 × 10 ４ or 8.0 x 10 ４ )

[0034] The weight average molecular weight can be measured by a GPC method, for example, under the following measurement conditions: Measurement apparatus: HLC-8320GPC (manufactured by TOSOH Corporation) Column: TSKgel GMH ＸＬ 4 bottles (manufactured by TOSOH) Eluent: THF Measurement temperature: 40°C Eluent flow rate: 1ml / min Sample concentration: 1mg / ml Injection volume: 100μl

[0035] The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the core resin is usually 0.5 or more, preferably 1.0 or more, and more preferably 1.5 or more. There is no upper limit to the ratio of the weight average molecular weight to the number average molecular weight of the core resin, but it is usually 5.0 or less, preferably 4.0 or less, and more preferably 3.0 or less. The number average molecular weight is measured in the same manner as the weight average molecular weight. The Mw / Mn range of the core resin is preferably 1.0 to 4.0, and more preferably 1.5 to 3.0 (e.g., 1.5, 2.0, 2.5, or 3.0).

[0036] In terms of inorganic filler filling, the content of the core resin contained in the flame-retardant metal-resin composite according to one embodiment of the present invention is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, based on 100 parts by mass of the core layer. In terms of suppressing the amount of heat generated by combustion of the core layer, the content of the core resin is preferably 10 parts by mass or less, more preferably 9 parts by mass or less, and even more preferably 8 parts by mass or less, based on 100 parts by mass of the core layer. The content of the core resin is preferably in the range of 1 to 10 parts by mass, more preferably 2 to 9 parts by mass, and even more preferably 3 to 8 parts by mass (e.g., 3, 4, 5, 6, 7, or 8 parts by mass), based on 100 parts by mass of the core layer.

[0037] [Metal Hydroxide] The metal hydroxide contained in the flame-retardant metal-resin composite according to one embodiment of the present invention is not particularly limited as long as it can absorb thermal energy by decomposition of the hydroxyl group. One or more types of metal hydroxides can be used.

[0038] In order to further improve the flame retardancy of the flame-retardant metal-resin composite, the metal hydroxide is preferably an inorganic metal hydroxide, more preferably a hydroxide of a trivalent metal or a hydroxide of an alkaline earth metal, still more preferably magnesium hydroxide, aluminum hydroxide, or calcium hydroxide, and particularly preferably aluminum hydroxide.

[0039] The average particle size of the metal hydroxide is not particularly limited, but is usually 0.1 to 200 μm, preferably 20 to 180 μm, and more preferably 50 to 150 μm (for example, 50, 100, or 150 μm). By setting the particle size of the metal hydroxide within the above range, the dispersibility of the metal hydroxide in the core layer is high, which is preferable in that the peel strength of the metal-resin composite is improved. The average particle size of the metal hydroxide is measured by the Microtrack method.

[0040] In order to further improve the flame retardancy of the flame-retardant metal-resin composite, the content of the metal hydroxide contained in the flame-retardant metal-resin composite according to one embodiment of the present invention is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and even more preferably 50 parts by mass or more, based on 100 parts by mass of the core layer. In order to ensure the face material peel strength of the metal-resin composite, the content of the metal hydroxide is preferably 95 parts by mass or less, more preferably 93 parts by mass or less, based on 100 parts by mass of the core layer. The content of the metal hydroxide is preferably in the range of 30 to 95 parts by mass (e.g., 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95 parts by mass), more preferably 40 to 93 parts by mass, and even more preferably 50 to 93 parts by mass, based on 100 parts by mass of the core layer.

[0041] [Flame Retardant] The flame retardant contained in the flame-retardant metal-resin composite according to one embodiment of the present invention includes at least one selected from the group consisting of inorganic polyphosphate compounds, inorganic phosphite compounds, inorganic phosphinate compounds, inorganic metaphosphate compounds, melamine compounds, and triazine compounds.

[0042] Examples of inorganic polyphosphate compounds include metal polyphosphates such as ammonium polyphosphate, aluminum polyphosphate, sodium polyphosphate, and calcium polyphosphate. In this specification, polyphosphate includes pyrophosphate, triphosphate, tetraphosphate, etc.

[0043] Inorganic phosphite compounds include, for example, metal phosphites such as aluminum phosphite, sodium phosphite, and calcium phosphite.

[0044] Examples of inorganic phosphinate compounds include metal phosphinates such as aluminum phosphinate, sodium phosphinate, and calcium phosphinate.

[0045] Examples of inorganic metaphosphate compounds include metal metaphosphates such as aluminum metaphosphate, sodium metaphosphate, and calcium metaphosphate.

[0046] Among the inorganic polyphosphate compounds, inorganic phosphite compounds, inorganic phosphites, and inorganic metaphosphate compounds, inorganic polyphosphate compounds are preferred, ammonium polyphosphate and metal polyphosphates are more preferred, and ammonium polyphosphate is even more preferred, in terms of further improving flame retardancy.

[0047] Examples of the melamine compound include reaction products of melamine with phosphoric acid compounds such as melamine phosphate, melamine polyphosphate, melamine orthophosphate, melamine phosphite, melamine hypophosphite, melamine metaphosphate, and melamine polymetaphosphate, as well as melamine, melamine cyanurate, melamine sulfate, melamine nitrate, and melamine borate. The melamine compound may also be a melamine condensate (e.g., melam, melem, or melon).

[0048] In terms of further improving flame retardancy, the melamine compound is preferably a reaction product of a phosphoric acid compound and melamine, melamine cyanurate or melamine sulfate, and more preferably melamine polyphosphate, melamine cyanurate or melamine sulfate.

[0049] Examples of the triazine compound include triazine ring-containing compounds such as cyanuric acid, acetoguanamine, and benzoguanamine.

[0050] The reason for the improved flame retardancy of the flame-retardant metal-resin composite according to one embodiment of the present invention is not fully understood, but is presumed to be due to the following mechanism. The flame retardant contained in the flame-retardant metal-resin composite is characterized by excellent dispersibility in the core resin. Due to this characteristic, the use of the flame retardant provides the excellent effect of improving the flame retardancy of the flame-retardant metal-resin composite according to one embodiment of the present invention. Furthermore, the flame-retardant metal-resin composite also provides the excellent effect of preventing a decrease in the adhesive strength between the core layer and the metal layer.

[0051] In order to ensure flame retardancy, the content of the flame retardant in the flame-retardant metal-resin composite according to one embodiment of the present invention is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, based on 100 parts by mass of the core layer. In order to reduce the amount of heat generated by combustion of the core layer, the content of the flame retardant is preferably 15 parts by mass or less, more preferably 13 parts by mass or less, and even more preferably 12 parts by mass or less, based on 100 parts by mass of the core layer. The content of the flame retardant is preferably in the range of 1 to 15 parts by mass, more preferably 2 to 13 parts by mass, and even more preferably 3 to 12 parts by mass (e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 parts by mass), based on 100 parts by mass of the core layer.

[0052] [Other Components] The core layer may contain one or more other components such as a filler, a silane coupling agent, a dispersant, a lubricant, a nonwoven fabric, a processing aid, a curing agent, a release agent, a pigment, a weathering agent, an antioxidant, a plasticizer, a sliding agent, and a foaming agent, as long as the effects of the present invention are not impaired.

[0053] Examples of fillers include fibrous fillers, granular fillers, and plate-like fillers. Fibrous fillers are fillers that have a fibrous shape. Plate-like fillers are fillers that have a plate-like shape. Granular fillers are fillers that have shapes other than fibrous and plate-like, including irregular shapes.

[0054] Examples of fibrous fillers include fibrous inorganic fillers such as glass fiber, carbon fiber, asbestos fiber, metal fiber, wollastonite, attapulgite, sepiolite, rock wool, aluminum borate whiskers, potassium titanate fiber, calcium carbonate whiskers, titanium oxide whiskers, and ceramic fibers; and fibrous organic fillers such as aramid fiber, polyimide fiber, and polyparaphenylene benzobisoxazole fiber. These may be used alone or in combination of two or more.

[0055] Examples of plate-like fillers and granular fillers include talc, kaolin clay, calcium carbonate, zinc oxide, calcium silicate hydrate, mica, glass beads (which may be hollow), glass flakes, glass powder, magnesium carbonate, silica, titanium oxide, alumina, barium sulfate, calcium sulfate, calcium sulfite, zinc borate, barium metaborate, aluminum borate, calcium borate, sodium borate, aluminum nitride, boron nitride, silicon nitride, and pulverized products of the above-mentioned fibrous fillers. These may be used alone or in combination of two or more.

[0056] The filler is preferably an inorganic filler, more preferably one or more selected from glass fiber, carbon fiber, glass beads, calcium carbonate, and magnesium carbonate. Use of such a filler can particularly improve the mechanical strength of the core layer.

[0057] The filler may be surface treated with a coupling agent such as a silane coupling agent.

[0058] Examples of dispersants include saturated fatty acid metal salts such as zinc stearate.

[0059] The lubricant may be, for example, an ester or amide of a saturated fatty acid. The processing aid may be an acrylic resin, a polyimide resin, or a polyolefin resin, and preferably a modified acrylic resin.

[0060] As the nonwoven fabric, a known nonwoven fabric can be used. By including a nonwoven fabric in the core layer, the shape of the core layer is stabilized, and the core layer can be rolled up for storage, transportation, etc.

[0061] In order to obtain a flame-retardant metal-resin composite with improved flame retardancy and high face material peel strength, it is preferable that the core layer contains 1 to 15 parts by mass of a flame retardant, 1 to 10 parts by mass of a resin, 30 to 95 parts by mass of a metal hydroxide, and 0 to 45 parts by mass of other components.

[0062] (Physical properties of core layer) The core layer has flame retardancy such that, in the following combustion test, no flame ignition occurs for 1 second or more within 120 seconds after being placed in an electric furnace and within 120 seconds after being removed from the electric furnace. [Combustion test] A core layer test piece having a length of 38 mm, a width of 38 mm, and a height of 3 mm is placed in an electric furnace having a heater output of 500 W, an internal dimension of 90 mm × 110 mm × 70 mm, and a temperature controlled at 800°C, so that the 38 mm × 38 mm surface of the core layer test piece is approximately perpendicular to the bottom surface of the electric furnace.

[0063] In this specification, "flame" refers to a state in which a flame continues to burn after ignition.

[0064] The core layer in the flame-retardant metal-resin composite according to one aspect of the present invention can be obtained by molding a core layer composition obtained by mixing components that constitute the core layer.

[0065] From the viewpoint of the dispersion state of the core resin and filler, the specific gravity of the core layer composition after sheet formation is usually 1.6 or more, preferably 1.7 or more. The upper limit of the specific gravity of the core layer composition after sheet formation is usually 2.5 or less, preferably 2.3 or less, more preferably 2.1 or less, and even more preferably 2.0 or less. The range of the specific gravity is preferably 1.6 to 2.3, more preferably 1.6 to 2.1, and even more preferably 1.7 to 2.0 (for example, 1.7, 1.8, 1.9, or 2.0).

[0066] The thickness of the core layer is not particularly limited, but is usually 1.0 to 8.0 mm, preferably 1.3 to 8.0 mm, more preferably 2.0 to 8.0 mm, even more preferably 2.0 to 6.0 mm, and particularly preferably 2.0 to 5.0 mm (for example, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0 mm).

[0067] <Metal Layer> Examples of the metal layer in the flame-retardant metal-resin composite according to one embodiment of the present invention include layers made of metals such as aluminum, stainless steel, iron, copper, titanium, tin, nickel, etc., or various alloys. As the metal layer, a layer made of aluminum, stainless steel, or iron is preferred, and a layer made of aluminum is more preferred.

[0068] Considering the strength of the flame-retardant metal-resin composite against external forces, the thickness of the metal layer is preferably 0.1 to 0.8 mm (for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8 mm).

[0069]

[0023] The flame-retardant metal-resin composite according to one embodiment of the present invention preferably further comprises an adhesive layer between the core layer and the metal layer. From the viewpoint of having affinity for both the core layer and the metal layer, the adhesive layer preferably contains a resin having at least one polar group selected from the group consisting of a hydroxyl group, a carboxyl group, an aldehyde group, an amino group, a glycidyl group, and a ketone group.

[0070] Examples of the resin having a polar group include polyvinyl alcohol resins, polyamide resins, modified polyolefin resins, olefin copolymers, acrylic resins, polyurethane resins, and epoxy resins. These resins can be used alone or in combination. Examples of the resin contained in the adhesive layer are the same as those of the resin contained in the core layer. The resin contained in the adhesive layer may be the same as or different from the resin contained in the core layer.

[0071] Among these, polyvinyl alcohol resins, polyamide resins, and olefin copolymers are preferred, and olefin copolymers are more preferred, because they have excellent adhesion between the resin and metal.

[0072] It is preferable that the adhesive layer is first formed on the metal layer and then bonded to the core layer.

[0073] There are no particular limitations on the thickness of the adhesive layer, but it is usually 5 to 100 μm, preferably 10 to 80 μm, and more preferably 20 to 60 μm (for example, 20, 30, 40, 50, or 60 μm).

[0074] <Other Layers> The flame-retardant metal-resin composite according to one embodiment of the present invention may further include other layers, such as a layer made of a nonwoven fabric. For example, the layer made of a nonwoven fabric may be disposed between the core layer and the metal layer. The nonwoven fabric may be a conventionally known nonwoven fabric, such as the nonwoven fabric disclosed in US 2003 / 0044998 A1.

[0075] <Physical Properties of Flame-Retardant Metal-Resin Composite> The flame-retardant metal-resin composite according to one embodiment of the present invention has a face material peel strength of 2.4 N / mm or more, preferably 3.1 N / mm or more, and more preferably 3.9 N / mm or more, measured in accordance with the test method of ISO 8510-2.

[0076] The flexural strength of the flame-retardant metal-resin composite material is usually 50 MPa or more, preferably 60 MPa or more.

[0077] The flexural modulus of the flame-retardant metal-resin composite material is usually 5.0 × 10 when the metal layer is aluminum. ３ N / mm ２ or more, preferably 3.0 × 10 ４ N / mm ２ There is no upper limit to the flexural modulus, but it is usually 7.0 × 10 ４ N / mm ２ When the metal layer is made of aluminum, the range of the flexural modulus of the flame-retardant metal-resin composite material is preferably 3.0 × 10 or less. ４ ~7.0 x 10 ４ N / mm ２ (For example, 3.0 × 10 ４ , 4.0 × 10 ４ , 5.0 × 10 ４ , 6.0 × 10 ４ or 7.0 x 10 ４ N / mm ２ )

[0078] When the metal layer is stainless steel or iron, the flexural modulus of the flame-retardant metal-resin composite material is usually 1.4 × 10 ４ N / mm ２ or more, preferably 3.0 × 10 ４ N / mm ２ Above, usually 2.0 x 10 ５ N / mm ２When the metal layer is stainless steel or iron, the range of the flexural modulus of the flame-retardant metal-resin composite material is preferably 3.0 × 10 or less. ４ ~2.0 x 10 ５ N / mm ２ (For example, 3.0 × 10 ４ , 5.0 × 10 ４ , 7.5 × 10 ４ , 1.0×10 ５ or 2.0 x 10 ５ N / mm ２ )

[0079] The bending stiffness of the flame-retardant metal-resin composite material is usually 1.0 x 10 ７ N mm ２ More preferably, 1.3 × 10 ７ N mm ２ That's all.

[0080] The flexural strength, flexural modulus and flexural rigidity of the flame-retardant metal-resin composite material are measured by using a two-point support method with a central single-point load on a sample (width 60 mm, span 200 mm) at a loading rate of 50 mm / min.

[0081] The overall thickness of the flame-retardant metal-resin composite is not particularly limited, as it is set appropriately depending on the application of the flame-retardant metal-resin composite, but is usually 1.5 mm or more, preferably 2.0 mm or more, more preferably 2.5 mm or more, and even more preferably 3.0 mm or more. The upper limit of the thickness of the flame-retardant metal-resin composite is not particularly limited, and may be 50 mm or less. The overall thickness of the flame-retardant metal-resin composite is preferably in the range of 2.0 to 50 mm, more preferably 2.5 to 50 mm, and even more preferably 3.0 to 50 mm (e.g., 3.0, 5.0, 10, 20, 30, 40, or 50 mm).

[0082] <Method for manufacturing a flame-retardant metal-resin composite> A method for manufacturing a flame-retardant metal-resin composite according to one embodiment of the present invention will be described. Methods for manufacturing a flame-retardant metal-resin composite according to one embodiment of the present invention are not particularly limited, but examples include injection molding, transfer molding, compression molding, and injection-compression molding. Of these, compression molding is particularly suitable.

[0083] An example of a method for producing a flame-retardant metal-resin composite material by compression molding is as follows.

[0084] The core resin, flame retardant, metal hydroxide, and, if necessary, the other components described above are mixed by a conventional method such as a mixer. (Preferably, the resin is melted by heating and kneading, and then the flame retardant, metal hydroxide, resin, etc. are uniformly mixed.) The core layer composition obtained by mixing is supplied onto the first metal layer having an adhesive layer. Next, it is superimposed on the second metal layer having an adhesive layer, and heated and pressurized by a conventional method such as a heat press. The adhesive layer of the second metal layer is positioned on the core layer side. There are no particular restrictions on the heating conditions, but a pressure of 140 to 200°C is preferred, and a pressure of 160 to 180°C is more preferred (e.g., 160, 170, or 180°C is more preferred). There are no particular restrictions on the pressure conditions, but a pressure of 300 to 1,000 N / cm is preferred. ２ , more preferably 500 to 800 N / cm ２ (e.g., 500, 600, 700, or 800 N / cm ２ The holding time is not particularly limited, but is preferably 1 to 60 seconds, and more preferably 10 to 30 seconds (for example, 10, 20, or 30 seconds). By the above operation, a flame-retardant metal-resin composite according to one embodiment of the present invention is obtained.

[0085] The flame-retardant metal-resin composite material containing a layer made of nonwoven fabric can be produced, for example, by the production method disclosed in US 2003 / 0044998 A1.

[0086] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed as different embodiments are also included in the technical scope of the present invention.

[0087] An embodiment of the present invention will now be described.

[0088] [Preparation of Materials] The abbreviations and / or details of the resins used in the following examples and comparative examples are as follows.

[0089] [Resin] PVB: Polyvinyl alcohol resin (polyvinyl butyral, weight average molecular weight (Mw) 2.1 × 10 ４ , Mw / number average molecular weight (Mn) 2.3, hydroxyl group mass concentration 18 to 21 mass%, combustion heat value 30.4 MJ / kg, tensile strength 46 MPa, melt viscosity 300 Pa·S) EVA: ethylene-vinyl acetate copolymer (VA content 80%, weight average molecular weight (Mw) 3.0 × 10 ５ , combustion heat generation amount 25.2 MJ / kg, tensile strength 2 MPa, melt viscosity 400 Pa·S) Polyamide: copolymer polyamide resin (melt viscosity (ISO 1133, 160°C / 2.16 kg) 150 Pa·S)

[0090] [Metal hydroxides] Aluminum hydroxide (average particle size: 105 μm) Magnesium hydroxide (average particle size: 3.5 μm)

[0091] [Inorganic filler] CaCO ３ (Calcium carbonate) MgCO ３ (Magnesium carbonate) Lightweight material (inorganic hollow filler mainly composed of silicon dioxide)

[0092] [Flame retardants] Melamine polyphosphate (product name MPP-A, manufactured by Sanwa Chemical Co., Ltd.) Ammonium polyphosphate (product name Taien K, manufactured by Taihei Chemical Industry Co., Ltd.) Melamine cyanurate (product name MC-6000, manufactured by Nissan Chemical Industries, Ltd.) Melamine sulfate (product name Apinon-901, manufactured by Sanwa Chemical Co., Ltd.) Amine phosphate / metal phosphate complex (product name FP-2100JC, manufactured by ADEKA Corporation) Guanidine phosphate (product name Apinon-303, manufactured by Sanwa Chemical Co., Ltd.)

[0093] [Examples 1 to 20, Comparative Examples 1 to 6] Using a 0.5 mm thick aluminum sheet having a 55 μm thick adhesive layer (ethylene-maleic anhydride copolymer) and a core layer composition, flame-retardant metal-resin composites were produced by the following procedure.

[0094] <Preparation of Core Layer Composition> Each component was blended according to the blending ratio shown in Tables 1 to 3, and melt-kneaded at 180° C. to prepare core layer compositions of Examples 1 to 20 and Comparative Examples 1 to 6.

[0095] <Heat Press Molding> The above-described core layer composition is applied onto an aluminum sheet having an adhesive layer, and an aluminum sheet having an adhesive layer is further placed thereon. The composition is then pressed at 180°C and 500 N / cm using a heat press. ２ The pieces were bonded together under a pressure of 0.5 MPa for 10 seconds to prepare a flame-retardant metal-resin composite material having a thickness of 4 mm.

[0096] Next, a combustion test of the core layer composition and a test for measuring the peel strength of the face material of the prepared flame-retardant metal-resin composite material were carried out.

[0097] <Combustion Test> Test specimens measuring 38 mm in length, 38 mm in width, and 3 mm in height were prepared from each core layer composition. For the combustion test, an electric furnace with a heater output of 500 W and furnace dimensions of 90 mm x 110 mm x 70 mm was used. The test specimens were fixed with a wire mesh so that the 38 mm x 38 mm surface of the test specimen was approximately perpendicular to the bottom of the furnace, and placed in the electric furnace, the temperature of which was controlled at 800°C. The test specimens were then visually inspected by an examiner for the presence or absence of a continuous flame of 1 second or more for 120 seconds after being placed in the electric furnace and for 120 seconds after being removed from the electric furnace.

[0098] <Measurement of Face Material Peel Strength> Measurement was performed using a method conforming to the ISO 8510-2 test method. A test specimen measuring 25.0 mm ± 0.5 mm wide and 150 mm long was prepared from a flame-retardant metal-resin composite. The first metal layer with the adhesive layer was peeled off approximately 60% of the length of the specimen, and the first metal layer was clamped between fixed grips, with the unpeeled side attached to the other grip. Care was taken to accurately attach the specimen between the grips so that tension was applied uniformly across the width of the specimen. Peeling was then performed at a rate of 100 mm / min, continuing until at least 50 mm had peeled. For each specimen, the average face material peel strength (N) was measured from the force-grip travel distance curve over the entire peel length, excluding the first 25 mm.

[0099] The components in each core layer composition, their blending ratios, the evaluation results of the combustion test, and the measurement results of the face material peel strength of the flame-retardant metal-resin composite are shown in Tables 1 to 3. The blending ratios of the components in each core layer composition are expressed in mass%.

[0100]

[0101]

[0102]

[0103] As shown in Tables 1 to 3, the test specimens made of the core layer composition included in the flame-retardant metal-resin composites of the examples did not show any flame ignition for 120 seconds after being placed in the electric furnace or for 120 seconds after being removed from the electric furnace. This indicates that the flame-retardant metal-resin composites using the core layer composition have improved flame retardancy.

[0104] Test specimens made of the core layer compositions contained in the flame-retardant metal-resin composites of Comparative Examples 1 to 3 were observed to continue flaming for at least one of 120 seconds after being placed in an electric furnace and 120 seconds after being removed from the electric furnace. The core layer compositions of Comparative Examples 1 to 3 did not contain a flame retardant. This demonstrates that flame-retardant metal-resin composites using core layer compositions that do not contain a flame retardant have insufficient flame retardancy.

[0105] Test specimens made of the core layer compositions contained in the flame-retardant metal-resin composites of Comparative Examples 4 to 6 were observed to continue flaming for at least 120 seconds after being placed in an electric furnace and for 120 seconds after being removed from the electric furnace. The core layer compositions of Comparative Examples 4 to 6 contained a flame retardant, but the amine phosphate-metal phosphate complexes used in Comparative Examples 4 and 5 and the guanidine phosphate used in Comparative Example 6 were flame retardants of a different type from the flame retardant of the present invention. This demonstrates that, in order to improve the flame retardancy of a flame-retardant metal-resin composite, it is not sufficient to simply add any flame retardant to the core layer composition, but rather it is necessary to add a specific flame retardant.

[0106] From the above, it was found that by incorporating a specific flame retardant, a flame-retardant metal-resin composite material with improved flame retardancy can be obtained.

[0107] The flame-retardant metal-resin composite material according to one embodiment of the present invention has excellent flame retardancy and is useful, for example, as an exterior building material such as an exterior wall material for a building.

Claims

1. A flame-retardant metal resin composite material comprising a core layer containing a resin and metal layers laminated on both sides of the core layer, wherein the core layer comprises: a metal hydroxide; a resin having at least one polar group selected from the group consisting of a hydroxyl group, a carboxyl group, an aldehyde group, an amino group, a glycidyl group, and a ketone group; and a flame retardant comprising at least one compound selected from the group consisting of inorganic polyphosphate compounds, inorganic phosphite compounds, inorganic phosphinate compounds, inorganic metaphosphate compounds, melamine compounds, and triazine compounds.

2. A flame-retardant metal resin composite as described in claim 1, in which the core layer does not ignite for 1 second or more within 120 seconds after being placed in an electric furnace and within 120 seconds after being removed from the electric furnace in the following combustion test: [Combustion test] A core layer test specimen measuring 38 mm in length, 38 mm in width and 3 mm in height is placed in an electric furnace with a heater output of 500 W, furnace interior dimensions of 90 mm x 110 mm x 70 mm, and the furnace interior controlled to 800°C, so that the 38 mm x 38 mm surface of the core layer test specimen is approximately perpendicular to the bottom surface of the electric furnace.

3. A flame-retardant metal-resin composite according to claim 1 or 2, wherein the face material peel strength of the metal-resin composite is 2.4 N / mm or more.

4. A flame-retardant metal resin composite material according to claim 1 or 2, wherein the resin is at least one resin selected from the group consisting of polyvinyl alcohol-based resins, polyamide-based resins, modified polyolefin-based resins, olefin-based copolymers, acrylic-based resins, polyurethane-based resins, and epoxy-based resins.

5. A flame-retardant metal resin composite according to claim 1 or 2, further comprising an adhesive layer between the core layer and the metal layer, the adhesive layer comprising a resin having at least one polar group selected from the group consisting of a hydroxyl group, a carboxyl group, an aldehyde group, an amino group, a glycidyl group and a ketone group.

6. A flame-retardant metal resin composite material according to claim 5, wherein the resin contained in the adhesive layer is at least one resin selected from the group consisting of polyvinyl alcohol-based resins, polyamide-based resins, modified polyolefin-based resins, olefin-based copolymers, acrylic-based resins, polyurethane-based resins, and epoxy-based resins.

7. The flame-retardant metal-resin composite material according to claim 1, comprising 1 to 15 parts by mass of the flame retardant per 100 parts by mass of the core layer.

8. The flame-retardant metal-resin composite material according to claim 7, wherein the resin is contained in an amount of 1 to 10 parts by mass per 100 parts by mass of the core layer.

9. The flame-retardant metal resin composite according to claim 7 or 8, which contains 30 to 95 parts by mass of the metal hydroxide per 100 parts by mass of the core layer.

10. The flame-retardant metal-resin composite according to claim 1, further comprising a layer of nonwoven fabric.

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