Refractory resin molded materials

Abstract

The objective is to provide fire-resistant resin molded products that achieve both sufficient fire resistance and ease of manufacture. [Solution] The fire-resistant resin molded product is composed of a binder made of synthetic resin and a non-binder component other than the binder, wherein the non-binder contains ammonium polyphosphate, a polyhydric alcohol, and titanium dioxide, and the titanium dioxide contains needle-shaped titanium dioxide. With this configuration, the fire-resistant resin molded product can be molded into the desired shape (pellets, sheets, etc.) and used, making it easy to implement. Furthermore, it is possible to achieve both fire resistance and ease of mixing during manufacturing.

Description

Technical Field

[0001] The technology disclosed by this specification relates to a fire-resistant resin molded product.

Background Art

[0002] As a fire-resistant coating material for coating building materials such as steel frames, a coating material made into a sheet shape by kneading a binder, a flame retardant, a foaming agent, a carbonized material, a filler, etc. has been proposed (see Patent Document 1). When this coating material is exposed to high temperatures due to a fire in a building, it foams and carbonizes to form a heat insulation layer, and this heat insulation layer protects the building material.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above coating material, in order to withstand the flames during a fire and maintain the shape of the heat insulation layer, if the foaming is weakened, the content of the foaming component that contributes to the fire resistance performance relatively decreases. Therefore, there is room for improvement in order to achieve both sufficient fire resistance performance and appropriate foaming height.

Means for Solving the Problems

[0005] The fire-resistant resin molded product disclosed by this specification is composed of a binder made of a synthetic resin and a non-binder which is a component other than the binder. The non-binder contains ammonium polyphosphate, a polyhydric alcohol, and titanium oxide, and the titanium oxide contains acicular titanium oxide.

[0006] Fire-resistant resin molded products with the above composition can be molded into desired shapes (pellets, sheets, etc.) and are therefore easy to install. Furthermore, in order to form a sufficiently thick insulating layer during a fire and to greatly increase the effect of slowing the conduction of combustion heat through endothermic reactions, it is desirable to have a higher content of ammonium polyphosphate and polyhydric alcohols. In order to suppress the sagging of the insulating layer and maintain its strength, it is desirable to have a higher content of titanium dioxide. However, increasing the content of these components relatively reduces the content of the binder, making mixing during manufacturing difficult. By including needle-shaped titanium dioxide, it is possible to suppress the sagging of the insulating layer and maintain its strength without increasing the titanium dioxide content.

[0007] In the above-described fire-resistant resin molded product, the aspect ratio (fiber length ÷ fiber diameter) of the needle-shaped titanium oxide may be 8 or more and 25 or less. Needle-shaped titanium oxide is a needle-shaped crystalline form of titanium oxide, having a specific particle shape with an average major axis length of about 1 to 10 μm and an average aspect ratio of about 3 to 150. In the present invention, the fiber length (major axis length) of needle-shaped titanium oxide is preferably 1.5 to 8 μm, and the fiber diameter is preferably 0.1 to 0.5 μm.

[0008] Various methods have already been proposed for producing needle-shaped titanium oxide. For example, Japanese Patent Publication No. 47-44974 describes a method in which a mixture consisting of titanium oxide, sodium chloride, and an oxyrin compound is calcined at a temperature of 725 to 1000°C, and the resulting calcined product is immersed to remove soluble salts. Japanese Patent Application Publication No. 2-239119 describes a method for producing needle-shaped titanium oxide by wet mixing a titanium source, an alkali metal source, and an oxyrin compound, and then calcining the resulting wet mixture slurry at 700 to 1000°C. Furthermore, Japanese Patent Application Publication No. 07-002598 describes a method in which an aqueous solution of titanium tetrachloride is heated and hydrolyzed to produce a hydrated titanium oxide slurry containing free hydrochloric acid, an alkali metal compound is added to the obtained slurry to form an alkali metal chloride salt, then an oxyrin compound is added, followed by dehydration, and the dehydrated cake is calcined at 700 to 1000°C. As shown in Table 2012 / 077414, it may also be synthesized using ordinary granular titanium oxide as a starting material. In the present invention, any product obtained by any of these manufacturing methods can be used, and the invention is not limited to these methods.

[0009] The content of needle-shaped titanium dioxide in 100 parts by mass of titanium dioxide is preferably 5 to 70 parts by mass.

[0010] In the above-mentioned fire-resistant resin molded product, the amount of non-binder may be 200 parts by mass or more and 400 parts by mass or less per 100 parts by mass of binder.

[0011] Furthermore, the fire-resistant structure of a structural member disclosed herein comprises a structural member having an insertion hole through which other members can be inserted, and a fire-resistant resin layer disposed on the inner circumferential surface of the insertion hole, wherein the fire-resistant resin layer is composed of a binder made of synthetic resin and a non-binder which is a component other than the binder, and the non-binder includes ammonium polyphosphate, a polyhydric alcohol and titanium dioxide, and the titanium dioxide includes needle-shaped titanium dioxide.

[0012] Furthermore, the method for constructing a fire-resistant structural member disclosed herein includes a kneading step of kneading a binder made of synthetic resin and a non-binder which is a component other than the binder; a molding step of forming the kneaded material obtained in the kneading step into a sheet; and a construction step of attaching the molded material obtained in the molding step to a structural member to form a fire-resistant resin layer, wherein in the kneading step, the non-binder includes ammonium polyphosphate, a polyhydric alcohol, and titanium dioxide, and the titanium dioxide includes needle-shaped titanium dioxide.

[0013] According to the fire-resistant structure of the structural members and the construction method for the fire-resistant structural members described above, when a fire occurs, the fire-resistant resin layer foams and expands and carbonizes, forming an insulating layer. This insulating layer suppresses the transfer of heat to the structural members.

[0014] In order to maximize the interior space, it is preferable to make the thickness of the fire-resistant resin layer relatively thin. On the other hand, in order to suppress heat transfer to structural members during a fire, and for the insulation layer to fill the gap between the inner surface of the through-hole and other members to some extent, and to exhibit sufficient fire resistance, it is desirable to form an insulation layer of sufficient thickness. The fire-resistant resin layer with the above composition has a sufficiently large foaming ratio (ratio of the thickness after foaming to the thickness before foaming), so it is possible to achieve both the necessary fire resistance and the desired performance. [Effects of the Invention]

[0015] The fire-resistant resin molded articles, fire-resistant structures for structural members, and construction methods for fire-resistant structural members disclosed herein make it possible to achieve both sufficient fire resistance and ease of manufacture. [Modes for carrying out the invention]

[0016] The embodiments will now be described. The fire-resistant resin molded product of this embodiment is manufactured by kneading a binder made of synthetic resin and a non-binder component other than the binder, and molding it into an arbitrary shape. It is suitably used as a fire-resistant coating material for covering construction objects such as building materials that require fire resistance. The non-binder includes ammonium polyphosphate as a flame retardant, a polyhydric alcohol as a carbonizing agent, and titanium dioxide as a thickening agent. The titanium dioxide further contains needle-shaped titanium dioxide. This fire-resistant resin composition foams and carbonizes due to the heat of combustion during a fire, forming an insulating layer.

[0017] The type of synthetic resin used as a binder is not particularly limited, but ethylene copolymer resins such as EVA (ethylene-vinyl acetate copolymer) and EEA (ethylene-ethyl acetate copolymer), vinyl chloride resins such as vinyl chloride and vinyl chloride-vinyl acetate copolymer, and synthetic rubbers such as butyl rubber and styrene-butadiene rubber can be used. In particular, it is preferable to use an ethylene copolymer resin that has excellent kneading properties. When using EVA as a binder, it is preferable that the VA ratio (vinyl acetate content) be 30 to 50% by mass in order to obtain a sufficient foaming ratio.

[0018] Among the non-binding agents, ammonium polyphosphate is a flame retardant that undergoes dehydration condensation and foaming due to the heat of combustion during a fire. This dehydration condensation is an endothermic reaction, which delays the conduction of heat of combustion to the coated object, such as steel frames, during a fire. The endothermic reaction is the deammonia reaction of ammonium polyphosphate.

[0019] Polyhydric alcohols are carbonizing agents and, like ammonium polyphosphate, undergo dehydration condensation and foaming due to the heat of combustion during a fire. The type of polyhydric alcohol is not particularly limited, but pentaerythritol or dipentaerythritol can be preferably used.

[0020] Titanium oxide is a thickening agent, and the heat insulation layer formed during a fire suppresses dripping from the object to be constructed and maintains the strength of the heat insulation layer. The larger the specific surface area of the titanium oxide used, the greater the dripping suppression effect, but the kneading during production becomes difficult. By containing acicular titanium oxide, the dripping suppression effect can be obtained without increasing the content of titanium oxide.

[0021] Acicular titanium oxide is a white acicular crystal, and the smaller the aspect ratio of the acicular titanium oxide, the higher the foaming suppression effect. The aspect ratio is calculated as fiber length ÷ fiber diameter, and it is preferably 8 or more and 25 or less.

[0022] The fiber length of the acicular titanium oxide is preferably 1 to 10 μm, and the fiber diameter is preferably 0.1 to 0.5 μm.

[0023] Commercially available acicular titanium oxide may be used. For example, EC-485 (manufactured by Titanium Industry Co., Ltd.), FTL (manufactured by Ishihara Sangyo Co., Ltd.), product number not available (manufactured by Fuji Titanium Industry Co., Ltd.), etc. can be mentioned.

[0024] The content of acicular titanium oxide in 100 parts by mass of titanium oxide is preferably 5 to 70 parts by mass.

[0025] In addition to the above, the non-binder may contain a mold release agent (fatty acid ester), a lubricant, a processing aid (such as polycarbodiimide), etc.

[0026] To form a sufficiently thick insulating layer during a fire and to maximize the effect of slowing the conduction of combustion heat through endothermic reactions, it is desirable to have a higher content of ammonium polyphosphate and polyhydric alcohols. To maximize the effect of suppressing the sagging of the insulating layer, it is desirable to have a higher content of titanium dioxide. However, increasing the content of these components relatively reduces the content of the binder, making mixing during manufacturing difficult. However, by including needle-shaped titanium dioxide, it is possible to greatly increase the effect of suppressing the sagging of the insulating layer without increasing the titanium dioxide content. Furthermore, if the non-binder is between 200 and 400 parts by mass per 100 parts by mass of binder, it is possible to achieve both fire resistance and ease of mixing during manufacturing.

[0027] The fire-resistant resin molded product of this embodiment may contain a foaming agent such as melamine.

[0028] The fire-resistant resin molded product of this embodiment may be a pellet obtained by melting and kneading the above material using, for example, a single-screw extruder or a twin-screw extruder, and then water-cooling and pelletizing the resulting kneaded material into strands that have been extruded into strings or rods; or it may be a pellet obtained by melting and kneading the above material using, for example, a Banbury mixer or a kneader mixer, and then cutting the resulting kneaded material into a plate shape using a stretching roll or the like, and then pelletizing it; or it may be a molded product obtained by molding pellets obtained by these methods into any shape using known molding methods such as press molding, extrusion molding, or injection molding; or it may be a molded product obtained by melting and kneading the molten kneaded material using, for example, a Banbury mixer or a kneader mixer without pelletizing it, and then molding the resulting kneaded material into a plate shape using a stretching roll or the like, or by molding it into any shape using known molding methods.

[0029] An example of how the fire-resistant resin molded product of this embodiment is suitably applied to the fire-resistant structure of a structural member is described below.

[0030] An epoxy resin adhesive is applied to the entire surface of a steel column (e.g., a square steel pipe) as a structural member, and a fire-resistant resin layer is placed on top. The fire-resistant resin layer is formed by attaching a sheet-shaped fire-resistant resin molded product, having the above configuration, to the surface of the steel column.

[0031] The adhesive is not limited to epoxy resin, and other synthetic resins may be used for bonding. Examples include acrylic resin, urethane resin, EVA resin, and polyolefin resin. These are preferably used in a solvent-free form (e.g., solvent-free liquid or hot melt). This configuration prevents the sheet from swelling due to the evaporation of solvents in the adhesive. Alternatively, double-sided tape may be used instead of adhesive, or an adhesive layer may be pre-applied to one side of a fire-resistant resin molded sheet and then attached to a steel column. The adhesive layer on the fire-resistant resin molded sheet may be applied by extrusion lamination, dry lamination, or by applying double-sided tape.

[0032] An example of a construction method for the fire-resistant structural members described above is explained below.

[0033] First, the materials for the refractory resin molded product described above are kneaded using a twin-screw extruder (kneading process). The resulting kneaded material is extruded into strands or rods, which are then water-cooled and pelletized to obtain pellets. These pellets are fed into a single-screw extruder and molded into sheets with a width of 60 to 1200 mm and a thickness of 2 mm (molding process). It is also possible to mold the molten kneaded material into sheets without pelletizing it.

[0034] The resulting sheet-like molded material is then attached to the surface of a steel column in the structural member with the above configuration to form a fire-resistant resin layer (construction process).

[0035] When a fire breaks out, the fire-resistant resin layer foams and expands, and also carbonizes, forming an insulating layer. This insulating layer suppresses heat transfer to the structural members.

[0036] <Example Test> [Equipment and materials used] As a twin-screw compounding extruder, we used the "HYPERKTX" manufactured by Kobe Steel, Ltd. EVA (ethylene-vinyl acetate copolymer) resin (VA ratio = 40% by mass), PP (polypropylene) resin, EEA (ethylene-ethyl acetate copolymer) resin, or vinyl chloride resin were used as binders.

[0037] Among the non-binding agents, ammonium polyphosphate was used as a flame retardant, pentaerythritol as a carbonizing agent, titanium dioxide as a thickener, melamine as a foaming agent, fatty acid ester as a processing aid, and adipic acid-based polyester as a plasticizer.

[0038] [Test Method] Each component shown in Tables 1 and 2 was melt-kneaded at 180°C using an open kneader, formed into a sheet using a twin-screw kneading extruder through a roller head, and then cooled to obtain a sheet composition with a thickness of 2 mm. This sheet composition was then cut into 50 mm squares. Ease of kneading was evaluated as follows: ○ if it could be kneaded in an open kneader within 30 minutes, △ if it took between 30 and 60 minutes, and × if it could not be kneaded even after 60 minutes.

[0039] Next, the obtained sheet was attached to a steel plate with double-sided tape to create a test specimen. This specimen was then placed vertically in an electric furnace and heated at 500°C for 1 hour to form an insulating layer. After removing the test specimen from the electric furnace, 40mm square, 13g calcium silicate boards were placed one by one on the insulating layer to evaluate its shape retention. The evaluation was as follows: ○ if the insulating layer did not collapse even when 6 or more calcium silicate boards were placed on it (13g x 6 = 78g, 78g ÷ 0.0016m2 ≈ 5kPa), △ if it collapsed with 2 to 5 boards, and × if it collapsed with 1 board. The expansion ratio was also measured. Furthermore, it was evaluated whether the insulating layer had sagged after heating. ○ if the displacement of the upper edge of the insulating layer was 5mm or less, △ if it was between 5mm and 10mm, and × if it was more than 10mm. The results are shown in Tables 1 and 2.

[0040] Note that the units of the numerical values ​​showing the mixing ratios of each component in Tables 1 and 2 are parts by mass. Furthermore, in Tables 1 and 2, the granular titanium dioxide has an average particle size of 0.25 μm and an oil absorption capacity of 20 g / 100 g. Needle-shaped titanium dioxide 1 has an average fiber length of 1.68 μm and an average fiber diameter of 0.13 μm (aspect ratio 12.9). Needle-shaped titanium dioxide 2 has an average fiber length of 2.86 μm and an average fiber diameter of 0.21 μm (aspect ratio 13.6). Needle-shaped titanium dioxide 3 has an average fiber length of 5.15 μm and an average fiber diameter of 0.27 μm (aspect ratio 19.1). All needle-shaped titanium dioxide have an oil absorption capacity of 35-60 g / 100 g.

[0041] [Table 1]

[0042] [Table 2]

[0043] [Results and Discussion] In Test Examples 1-22, which contained needle-shaped titanium dioxide in titanium dioxide, the mixture was successfully molded into pellets. Furthermore, the insulation layer maintained its shape well, and no sagging was observed. The expansion ratio ranged from 5 to 29 times, which was sufficient to ensure the necessary fire resistance when applied to the surface of, for example, steel columns in structural members. In particular, in Test Examples 8-13, 15, 17, 19, and 21, where the binder was EVA resin or EEA resin and the needle-shaped titanium dioxide content in titanium dioxide was 7.7-26% by mass, no sagging of the insulation layer occurred despite expansion ratios exceeding 20 times. Although Test Example 26 required a longer mixing time, the insulation layer maintained its shape well, and no sagging was observed.

[0044] In Test Example 1, which did not include needle-shaped titanium dioxide, mixing was easy and a sufficient foaming ratio was obtained, but the shape retention of the insulation layer was insufficient, and sagging was observed. In Test Examples 23 (lacking titanium dioxide), 24 (lacking ammonium polyphosphate), and 25 (lacking pentaerythritol), the foaming ratio was insufficient, or sagging of the insulation layer was observed.

[0045] In order to achieve a good balance of performance in maintaining the shape of the insulation layer, sufficient foaming ratio, and suppression of sagging of the insulation layer, it was considered preferable to include needle-shaped titanium oxide in the titanium oxide.

[0046] <Other Embodiments> The technologies disclosed herein are not limited to the embodiments described above, but also include various other embodiments, such as the following:

[0047] Fire-resistant resin compositions can be used for various purposes by molding them into desired shapes. For example, they can be molded into sheets and used as fire-resistant coatings for steel structures. They can also be molded into tapes and placed in gaps in window frames, door frames, etc., to expand during a fire and fill the gaps, preventing flames from penetrating to the back. They can also be used as fire-resistant coating tapes on the outer surface of resin or wooden window frames to prevent combustion heat from burning the resin or wooden frames during a fire. Furthermore, they can be molded into plates and used as lightweight fire shutters. They can also be molded into films and used as films to suppress combustion in the event of a fire in storage batteries such as lithium-ion batteries, or as sheets to protect against sparks during welding. In addition, they can be molded into appropriate shapes and used as automotive parts to suppress ignition due to temperature rise during a fire by being placed on the outer surface of hydrogen tanks or gasoline tanks, or as parts to protect the interior of a vehicle's fuel tank during a fire.

Claims

1. It is composed of a binder made of synthetic resin and a non-binder component other than the binder, The non-binding agent comprises ammonium polyphosphate, a polyhydric alcohol, and titanium dioxide. A fire-resistant resin molded product wherein the titanium oxide contains needle-shaped titanium oxide.

2. The fire-resistant resin molded article according to claim 1, wherein the aspect ratio (fiber length ÷ fiber diameter) of the needle-shaped titanium oxide is 8 or more and 25 or less.

3. The fire-resistant resin molded article according to claim 1 or claim 2, characterized in that the content of needle-shaped titanium oxide in 100 parts by mass of titanium oxide is 5 to 70 parts by mass.

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