Resin composition, fire-resistant member, and fitting

Abstract

Provided is a technology relating to a resin composition in which an "initial fire expansion product" formed at 250 °C., which simulates an earlier initial fire stage, exhibits an appropriate expansion ratio that is more effective for suppressing and preventing fire spread in the initial fire stage, and an appropriate hardness ("shape retainability") that does not cause the shape to collapse, and which can also satisfy moldability ("gel characteristics") with which a fire-resistant sheet, a fire-resistant material, or the like can be formed without problems even though the resin composition uses a thermally expandable graphite having a low expansion start temperature.SOLUTION: A resin composition containing, in 100 parts of a polyvinyl chloride-based resin, 50 parts or more and 150 parts or less of thermally expandable graphite having an expansion start temperature of 175 °C to 200 °C, 10 parts or more and 30 parts or less of an amino group-containing compound and / or a phosphorus compound, and 2.5 parts or more and 10 parts or less of palladium-supported zinc having palladium supported thereon, and a method for producing the resin composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a fire-resistant member, and a building material, and more particularly to a resin composition containing a polyvinyl chloride resin and thermally expandable graphite, and particularly to a technology for providing a thermally expandable vinyl chloride resin material that is more useful and effective in preventing the spread of fire in the early stages of a fire and has no problems with formability, such as a resin composition suitable for forming fire-resistant sheets, fire-resistant members, and the like. [Background technology]

[0002] Fire-resistant sheets and fire-resistant members have been produced from resin compositions containing thermally expandable graphite by various molding methods and used in building fixtures. Opening, closing, and sliding movements are essential for building fixtures, and gaps are necessary to accommodate these mechanisms. The gaps allow fire and smoke generated in the early stages of a fire to pass through, accelerating the spread of the fire. Furthermore, rolls are often attached to building fixtures to allow smooth sliding, and these rolls also present the following problems. Generally, rolls are made of polyolefin, nylon, polyacetal, ABS, and the like. These resins soften or decompose and burn at temperatures below 250°C, which increases the number of gaps through which fire and smoke generated in the early stages of a fire can pass, resulting in the spread of the fire.

[0003] To address the above-mentioned problems, for example, thermally expandable fire-resistant sheets or fire-resistant materials are attached to the inside of various fittings such as window sashes and doorways, effectively blocking the passage of fire and smoke generated in the event of a fire from passing through the gaps in the fittings. Specifically, the fire-resistant sheets or fire-resistant materials attached to the fittings begin to expand rapidly in the event of a fire, causing the insulating expandable body to protrude from the window sash or doorway and fill the gaps, thereby blocking the passage of fire and smoke in the event of a fire, and in particular, the blocking effect of the fittings suppresses and prevents the spread of a fire in the early stages.

[0004] In response to the above, the applicant has already proposed in Patent Document 1 a thermally expandable polyvinyl chloride resin material that is useful and effective for preventing the spread of fire in the early stages of a fire. The invention described in Patent Document 1 aims to find a dehydrochlorination catalyst for accelerating the dehydrochlorination of polyvinyl chloride resin (i.e., the decomposition of polyvinyl chloride resin). After extensive research, the applicant discovered that only certain substances cause a significant weight loss (25% or more) of polyvinyl chloride resin at low temperatures, and that these substances function effectively as dehydrochlorination catalysts. The technology described in Patent Document 1 adds a substance that functions as a dehydrochlorination catalyst to a polyvinyl chloride resin material, thereby achieving the properties of an expandable body (hereinafter referred to as a "fire early stage expandable body") in the low temperature range at the early stage of a fire (below 250°C, the temperature at which various resins soften or decompose and burn) that can form an effective insulating layer that provides excellent insulation against fire and smoke, especially in the early stages of a fire. The technology of Patent Document 1 makes the thermally expandable body heated at high temperatures (800°C in Patent Document 1) have an unprecedented high cohesive strength and excellent shape retention, which also makes it possible to provide a fire-resistant sheet and fire-resistant member that are useful and effective against fires. In the specification of this application, the expandable body when heated at high temperatures will be called a "high-temperature thermally expandable body" to distinguish it from the "fire initial stage expandable body" that is the subject of the present invention.

[0005] The technology described in Patent Document 1 above has discovered an effective dehydrochlorination catalyst that, when added to a resin composition, decomposes (initiates dehydrochlorination) polyvinyl chloride resin used as a resin component at a temperature lower than the thermal decomposition initiation temperature of the resin, thereby realizing the provision of a vinyl chloride resin material that is effective in inhibiting the spread of fire, particularly in the early stages of a fire. Patent Document 1 discloses that zinc oxide, metallic zinc, zinc carbonate, zinc chloride, iron chloride, etc. are effective components for lowering the decomposition initiation temperature of vinyl chloride resin. In particular, the technology discloses that adding zinc oxide or metallic zinc to a resin composition primarily composed of vinyl chloride resin has a significant effect on lowering the decomposition initiation temperature of vinyl chloride resin.

[0006] As mentioned above, fire-resistant sheets and fire-resistant members intended to suppress the spread of fire are made by various molding methods from resin compositions containing thermally expandable graphite. According to the inventors' research, the expansion onset temperature, expansion ratio, and strength of the expanded body after expansion of the thermally expandable graphite that constitutes the resin composition and expands upon heating are diverse and not constant. Therefore, the performance of the fire-insulating effect of building materials made from resin compositions containing thermally expandable graphite also varies. Among these, the expansion onset temperature and expansion ratio of the thermally expandable graphite, which are directly related to the properties of the "fire initial expansion body" in the early stages of a fire, are particularly important characteristics.

[0007] Thermally expandable graphite, a key component determining the fire and smoke insulation effect of the above-mentioned building materials in the early stages of a fire, is a component of a resin composition, and therefore increases in volume during thermal expansion while experiencing resistance from the resin components contained therein. Naturally, the resin components are difficult to expand when they are hard, so the relationship between the state of the resin components during combustion and the expansion progression of the graphite is important. In particular, the early stages of a fire are related to the occurrence of gaps due to the aforementioned softening or decomposition and burning of resins used in building materials at temperatures below 250°C. Therefore, the correlation between the expansion onset temperature of the thermally expandable graphite that constitutes the resin composition and the thermal decomposition onset temperature of the resin at temperatures below 250°C becomes important.

[0008] In contrast to the technology described in Patent Document 1, Patent Document 2, while not intended to provide a fire and smoke barrier effect for building materials in the early stages of a fire, discloses an invention that focuses on the decomposition onset temperature of a resin component and the expansion onset temperature of expandable graphite. The technology described in Patent Document 2 aims to provide a resin composition that combines high expandability and high residual hardness. Patent Document 2 lists synthetic resins such as thermoplastic resins and thermosetting resins, or rubber, as the target resin components. It also states that "high expandability" and "high post-combustion residual hardness" are achieved when the expansion onset temperature of the thermally expandable graphite constituting the resin composition is lower than the decomposition onset temperature of the resin component, or even when the difference between the two is large. Specifically, "high expandability" is evaluated by measuring the thickness of a test specimen after heating at 600°C for 30 minutes and then calculating the ratio of the thickness to the original thickness as the expansion ratio. "High post-combustion residual hardness" is evaluated by compressing the heated test specimen, after measuring the expansion ratio, using a compression tester to measure the stress at break. In other words, the technology described in Patent Document 2 is concerned with the characteristics of the residue that hardens when heated at a high temperature "after heating at 600°C for 30 minutes," i.e., the "high-temperature thermal expansion body," and is not a technology that concerns the "initial expansion body at the time of fire" of a resin composition that is formed by the thermal decomposition of the resin component and the start of expansion of the thermally expandable graphite used in combination in the low-temperature range at the initial stage of a fire, which is the object and issue of the present invention. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 5992589 [Patent Document 2] Special Publication No. 2016-031905 Summary of the Invention [Problem to be solved by the invention]

[0010] In contrast to the above-mentioned conventional technology, the present invention aims to further improve the technology described in Patent Document 1 to create a "fire early expansion body" that can more effectively suppress and prevent the spread of fire in the early stages. To this end, the present invention first uses, as a resin component, a polyvinyl chloride resin, for which the technology described in Patent Document 1 has been found to be effective in lowering the decomposition onset temperature of vinyl chloride resins, as described above. This means that the resin composition of the present invention can lower the decomposition onset temperature of the polyvinyl chloride resin used. Furthermore, since the aim is to create a more effective "fire early expansion body," the present invention uses thermally expandable graphite with a lower expansion onset temperature than conventional products, specifically, 175°C to 200°C, to be used in combination with the polyvinyl chloride resin with a lower decomposition onset temperature. The technology described in Patent Document 1, cited above, uses thermally expandable graphite with an expansion onset temperature of 180°C to 240°C. The inventors have recognized the usefulness of using the above basic configuration to realize the formation of a "fire early stage expansion body" that is highly effective in suppressing and preventing the spread of fire at an earlier stage in the early stages of a fire, in a lower temperature range than that achieved by the technology described in Patent Document 1 described above.

[0011] The present inventors have discovered a unique problem with resin compositions having the above-described basic structure: for example, when producing a fire-resistant sheet by coating a sol-like resin composition on release paper and gelling it, a temperature load of up to approximately 170°C is applied, which may cause the constituent thermally expandable graphite to begin expanding, resulting in reduced product yield and reduced productivity. The present inventors have discovered that when a thermally expandable fire-resistant sheet or fire-resistant component is formed from a resin composition having a basic structure comprising a polyvinyl chloride resin with a lowered decomposition onset temperature in combination with thermally expandable graphite having an expansion onset temperature of 175°C to 200°C, a "fire initial expansion body" with excellent fire spread suppression and prevention effects can be formed at an earlier stage of a fire than achieved with conventional technology, and that in order to achieve a resin composition with the above-described moldability problem, it is necessary to precisely control the decomposition onset temperature of the constituent polyvinyl chloride resin and the expansion onset temperature of the combined thermally expandable graphite. Given the current state of these materials, we realized that a measurement method to objectively identify these temperatures was necessary. As will be discussed later, there are various challenges in measuring these temperatures.

[0012] The technology described in Patent Document 2 mentioned above does not address the issue of suppressing or preventing the spread of fire in the early stages, which is a problem addressed by the invention described in Patent Document 1 and the technology of the present invention, but it describes a configuration that focuses on the decomposition start temperature of the resin component and the expansion start temperature of the expandable graphite, which greatly affect the differences in the properties of the "expandable body in the early stage of a fire" that is the problem addressed by the present invention. The technology described in Patent Document 2 states that "when chlorinated polyvinyl chloride resin or polyvinyl chloride resin is used as the resin component, the expansion start temperature of the thermally expandable graphite is usually 215°C or lower," and in the examples it states that "the decomposition start temperature of polyvinyl chloride resin (degree of polymerization 1000) is 215°C," but does not disclose any method for measuring this temperature. As described above, in the technology described in Patent Document 2, the decomposition onset temperature of polyvinyl chloride resin and the expansion onset temperature of thermally expandable graphite are treated as having definite characteristic values. However, as mentioned above, at least the decomposition onset temperature of polyvinyl chloride resin is lowered by the presence of a dehydrochlorination catalyst, and as will be described later, there is no standardized measurement method or definition for the expansion onset temperature of thermally expandable graphite, and therefore various measurement methods are adopted in fields that handle thermally expandable graphite, and currently there is no value that can be uniquely determined.

[0013] As described above, various fixtures used in buildings, such as window sashes and doorways, are expected to exhibit the extremely important function of effectively blocking fire and smoke generated in the early stages of a fire from passing through gaps in the fixtures. Therefore, the object of the present invention is to further improve the technology of Patent Document 1 to realize a more useful resin composition. Specifically, the object of the present invention is to provide a resin composition that has excellent shape retention and high viscosity when heated at a high temperature (800°C), as achieved by the technology of Patent Document 1, and that has an "early stage of fire expansion body" of the resin composition that is generated when heated for a short period of time at a low temperature (250°C or less), which is intended to simulate the early stage of a fire, exhibits a moderate expansion ratio and moderate hardness that prevents shape loss (referred to as "shape retention" in the present invention), which are more effective in suppressing and preventing the spread of fire in the early stages of a fire, and that uses thermally expandable graphite with a low expansion onset temperature, yet has satisfactory moldability (referred to as "gel properties" in the present invention) that allows it to be easily formed into fire-resistant sheets, fire-resistant components, and the like. [Means for solving the problem]

[0014] The above object can be achieved by the present invention, which provides the following resin composition. [1] A resin composition comprising 100 parts by mass of polyvinyl chloride resin, 50 parts by mass or more and 150 parts by mass or less of thermally expandable graphite having an expansion onset temperature of 175°C to 200°C, 10 parts by mass or more and 30 parts by mass or less of an amino group-containing compound and / or a phosphorus compound, and 2.5 parts by mass or more and 10 parts by mass or less of palladium-supported zinc.

[0015] Preferred forms of the above resin composition include the following. [2] The resin composition according to the above [1], wherein the amount of palladium carried on the palladium-supported zinc is in the range of 0.01% by mass or more and 0.15% by mass relative to 100% by mass of the zinc. [3] The resin composition according to [1] or [2] above, wherein the phosphorus compound and / or amino group-containing compound is at least one selected from the group consisting of melamine cyanurate, melamine polyphosphate, melamine-melam-melem polyphosphate, melamine phosphate, melamine polyphosphate metal salt, piperazine phosphate, ethylenediamine phosphate, melamine sulfate, melamine, melem, benzoguanamine, melamine-coated ammonium polyphosphate, silane-coated ammonium polyphosphate, ethylenediamine polyphosphate metal salt, ammonium polyphosphate, and spirocyclic diphosphonates. [4] The resin composition according to any one of the above [1] to [3], which is in the form of a fire-resistant sheet. [5] The resin composition according to any one of the above [1] to [4], wherein the expansion starting temperature is the temperature at which the volume of the thermally expandable graphite increases by 1.1 times when the thermally expandable graphite is heated at a temperature increase rate of 10°C / min.

[0016] As another embodiment, the present invention provides the following fire-resistant member and fittings including the fire-resistant member. [6] A fire-resistant member comprising the resin composition according to any one of the above [1] to [5]. [7] A fixture characterized by comprising the fire-resistant member described in [6] above. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a resin composition that can realize the extremely important function required of building fixtures, in particular, of effectively blocking the passage of fire and smoke generated in the early stages of a fire through gaps in the fixtures. The "fire initial stage expandable body" formed at 250°C, which is designed to anticipate the earliest onset of a fire, exhibits a moderate expansion ratio and moderate hardness ("shape retention") that is more effective in suppressing and preventing the spread of fire in the early stages of a fire, and yet has satisfactory moldability ("gel properties") that allows it to be formed into fire-resistant sheets, fire-resistant structural materials, etc. without any problems, despite being a resin composition that uses thermally expandable graphite with a low expansion onset temperature. Specifically, according to the present invention, the resin composition is configured by using a specific amount of metallic zinc supported on palladium (abbreviated as "palladium-supported zinc" in the present invention) as a dehydrochlorination catalyst that can lower the decomposition onset temperature of polyvinyl chloride resins, and by using a specific amount of thermally expandable graphite whose expansion onset temperature is in the range of 175°C to 200°C, which is lower than conventional products. This makes it possible to provide a "fire early expansion body" that is more useful for suppressing the spread of fire in the early stages of a fire at a lower temperature than conventional products, enables the formation of an effective heat insulating layer, and also makes it possible to provide a resin composition that does not have any problems with formability when forming fire-resistant sheets, fire-resistant components, etc. [Brief explanation of the drawings]

[0018] [Figure 1] This is a graph showing the change in the expansion ratio of three types of thermally expandable graphite, all of which have an expansion starting temperature of around 160°C, when heated sequentially in a low temperature range. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described in detail below with reference to preferred embodiments. The inventors of the present invention have conducted extensive research into resin compositions that combine a polyvinyl chloride resin with a reduced decomposition temperature with thermally expandable graphite having an expansion onset temperature of 175°C to 200°C, a temperature lower than that of conventional products, and have succeeded in realizing a new resin composition in which the "high-temperature thermally expandable body" exhibits high caking strength and excellent shape retention, similar to conventional products, and in which the "fire early stage expansion body" is capable of forming an effective heat insulating layer that provides excellent insulation against fire and smoke that breaks out at an early stage of a fire, even in a temperature range lower than that of conventional products. Furthermore, despite the use of expandable black graphite with a low expansion onset temperature, the resin composition exhibits favorable moldability with no problems with "gel properties" when used to produce products such as fire-resistant sheets.

[0020] The resin composition of the present invention is characterized by containing, per 100 parts by mass of polyvinyl chloride resin, 50 parts by mass or more and 150 parts by mass or less of thermally expandable graphite having an expansion onset temperature of 175°C to 200°C, 10 parts by mass or more and 30 parts by mass or less of an amino group-containing compound and / or a phosphorus compound, and 2.5 parts by mass or more and 10 parts by mass or less of palladium-supported zinc.

[0021] According to the inventors' investigations, in order to further improve the aforementioned fire spread prevention effect in the early stages of a fire, it is desirable to further lower the thermal decomposition temperature of the polyvinyl chloride resin constituting the resin composition. Therefore, the inventors conducted extensive research to find a dehydrochlorination catalyst that can lower the dehydrochlorination onset temperature (i.e., the thermal decomposition onset temperature) of the polyvinyl chloride resin constituting the resin composition of the present invention below that used in the technology described in Patent Document 1. As a prerequisite for this, a method for measuring the thermal decomposition onset temperature of the polyvinyl chloride resin is important. Examples of polyvinyl chloride resins constituting the present invention include polyvinyl chloride resin, chlorinated vinyl chloride resin, copolymer resins of vinyl chloride and vinyl acetate, and copolymer resins of vinyl chloride and ethylene. Below, polyvinyl chloride resin is described as a representative example.

[0022] As mentioned above, lowering the thermal decomposition onset temperature of polyvinyl chloride resin in a resin composition is particularly important for achieving improved fire spread prevention in the early stages of a fire. Numerous literature and various reports have been published on the thermal decomposition onset temperature of polyvinyl chloride resin. For example, "Hara Yasutoku: Kyushu Institute of Technology Research Report (Engineering)," 20, p. 51 (1970)" states that, based on the results of micro-differential thermal analysis, a temperature below 160°C was observed at a heating rate of 10°C / min. Although the decomposition rate was slow, decomposition of polyvinyl chloride resin already began at 150°C. Furthermore, "Yano Shoichiro: Fibers and Industry, Vol. 31, No. 91 (1975)" states that, based on the behavior of dynamic viscoelasticity measurements, thermal decomposition of polyvinyl chloride resin begins around 210°C. These findings suggest that there is considerable variation in the determination of the onset temperature of thermal decomposition of polyvinyl chloride resin, depending on the measurement method.

[0023] In the aforementioned prior art, Patent Document 2, the "resin decomposition onset temperature" is described as "the temperature at which weight loss begins to be confirmed." However, Patent Document 2 does not disclose the specific weight loss percentage used in the evaluation, which is necessary to objectively evaluate "weight loss begins to be confirmed," nor does it disclose the heating rate, which is necessary as an objective standard for measurement. Regarding the decomposition onset temperature of polyvinyl chloride resin, Patent Document 2 only states that the decomposition onset temperature of polyvinyl chloride resin (PVC) used in the examples is 215°C. There is no mention of the brand name of this PVC, and of course, there is no mention whatsoever of a method for measuring the decomposition onset temperature.

[0024] Typically, the thermogravimetric measurement of resins is performed using the standardized JIS K 7120 standard, with a heating rate of 10°C / min. The weight loss curve for resin decomposition using the JIS method is extremely gentle initially, but generally increases linearly after passing that range. The inventors used Ryuron Paste 772A (product name: Tosoh Corporation, degree of polymerization: 1650) as an example of PVC. They measured the resin decomposition onset temperature at a heating rate of 10°C / min in accordance with JIS K 7120 for three types of samples: this PVC sample; a sample in which palladium-supported zinc was added to this PVC, which was found to function highly as a dehydrochlorination catalyst in this invention; and a sample in which zinc oxide was added, which was found to function as a dehydrochlorination catalyst in Patent Document 1. The results showed that for the PVC-only sample, the onset of decomposition was 200°C when the weight loss was 0.5% and 217°C when the weight loss was 1%. In contrast, for a sample in which 5.0 parts by mass of palladium-supported zinc was added to 100 parts by mass of PVC, the onset of decomposition was evaluated as 173°C when the weight loss reached 0.5%, demonstrating that the addition of this material effectively functions as a dehydrochlorination catalyst and can effectively lower the PVC decomposition temperature. Furthermore, for a sample in which 5.0 parts by mass of zinc oxide was added to 100 parts by mass of PVC, the onset of decomposition was evaluated as 179°C when the weight loss reached 0.5%, which was inferior to the case in which palladium-supported zinc was added, but similarly reduced the PVC decomposition onset temperature.

[0025] For the PVC described in the examples of Patent Document 2 as having a "decomposition onset temperature of 215°C," the conditions for measuring the decomposition onset temperature, such as the rate of temperature rise, and the weight loss percentage at the time when the onset of decomposition was evaluated are not described. However, assuming that the measurement was performed using the JIS method described above, and further referring to the measurement results for the PVC-only sample performed above, it is presumed that the evaluation was performed by considering the point at which the weight loss reached 0.5% to 1% as the onset of decomposition. However, at least considering the trend of the weight loss curve resulting from resin decomposition measured using the JIS method described above, and the fact that the decomposition onset temperature determined by the weight loss value used for evaluation varies greatly, as exemplified above for the PVC-only sample, it is not possible to objectively evaluate the decomposition onset temperature of a resin unless a measurement method and evaluation criteria for determining the onset of decomposition are defined. In the present invention, the decomposition onset temperature of the polyvinyl chloride resin constituting the resin composition of the present invention was determined by measuring the weight loss caused by thermal decomposition of the resin at a heating rate of 10°C / min in accordance with JIS K 7120, a standardized method for thermogravimetric measurement of resins, and the temperature at which the weight (mass) decreased by 0.5% was evaluated as the thermal decomposition onset temperature of the resin.

[0026] The applicant has also discovered an amino group-containing compound and / or phosphorus compound that suppresses the catalytic function of the dechlorination catalyst used in Patent Document 1. The use of these compounds has provided a technology for providing a thermally expandable polyvinyl chloride resin material that, when heated to 800°C, produces an expandable body with a high expansion ratio, higher caking strength, better shape retention, and mechanical strength, and that can more effectively block flames and smoke from low temperatures (see Patent Publication No. 6228658). This means that by using a dechlorination catalyst such as zinc oxide in combination with an amino group-containing compound that can suppress the catalytic function, it is possible to obtain a "fire initial expansion body" that satisfies the intended temperature range for the thermal decomposition of polyvinyl chloride resin, which occurs in the early stage (low temperature range) of fire heating of the resin composition. Furthermore, it is possible to obtain a "high-temperature heat-expandable body" in the final stage of fire heating of the resin composition, which exhibits a high expansion ratio, higher caking strength, better shape retention, and better mechanical strength. Among the compounds disclosed in the above-mentioned technologies, when melamine cyanurate, melamine polyphosphate, melamine melam melem polyphosphate, melamine, etc. are used, another effect is that fire-resistant sheets, fire-resistant materials, etc. manufactured from resin compositions containing these compounds can be made to have excellent water resistance. The present invention aims to provide a resin composition that, without impairing the effects of the inventions described in the above-mentioned prior art, enables the formation of an "initial fire expansion body" that is formed in the early stage (low temperature range of 250°C or less) when a product made of the resin composition is heated in a fire, and enables the formation of an insulating layer that can provide an effective barrier against fire and smoke at an earlier stage.

[0027] Next, thermally expandable graphite will be considered. There is no standardized official method for measuring the expansion onset temperature of thermally expandable graphite used in combination with a polyvinyl chloride resin that constitutes a thermally expandable resin composition, and various methods have been used, as will be described later. For this reason, it is necessary to find an objective measurement method suitable for the purpose of the present invention for measuring the expansion onset temperature of thermally expandable graphite and to carry out the above considerations.

[0028] The "thermally expandable graphite" constituting the present invention is widely used and is prepared by immersing crushed particles of natural flake graphite, pyrolytic graphite, or cash graphite in an inorganic or organic acid such as concentrated sulfuric acid, nitric acid, or phosphoric acid, and then using a strong oxidizing agent such as concentrated nitric acid, perchlorate, permanganate, dichromate, or hydrogen peroxide to form a graphite intercalation compound. Because the compound thus obtained is acidic, it is generally neutralized with a basic compound, such as ammonia, aliphatic lower amines, alkali metal compounds, or alkaline earth metal compounds. The particle size of the graphite particles is preferably approximately 20 mesh to 500 mesh. However, in the resin composition of the present invention, the particle size range of the thermally expandable graphite is not particularly limited. Generally, a larger particle size of the thermally expandable graphite results in a better expansion ratio of the expandable body. However, a smaller particle size is preferable from the viewpoint of ease of production of the resin composition and the use of the composition in the manufacture of fire-resistant sheets and fire-resistant components. Taking these factors into consideration, the particle size of the graphite particles used in the present invention is appropriately selected. The content of the graphite intercalation compound varies depending on the type of strong acid used for immersion, the time, the temperature, etc.

[0029] The thermal expansion behavior of the thermally expandable graphite prepared as described above, i.e., the expansion onset temperature, expansion ratio, and the caking strength of the thermally expandable body of a resin composition containing the thermally expandable graphite, vary significantly depending on the chemical treatment details, such as the type and amount of the intercalation compound of the thermally expandable graphite, and the shape of the graphite. The expansion onset temperature is particularly important, and various technical studies have been conducted to date. For example, Japanese Patent Laid-Open No. 2007-45676 discloses that the expansion onset temperature of thermally expandable graphite can be increased from approximately 200°C to 300°C or higher by adding an alkaline earth metal oxide or the like after acid treatment. Japanese Patent Laid-Open No. 10-330108 also discloses that the expansion onset temperature of thermally expandable graphite can be increased to 250°C or higher by adding phosphoric acid to the acid treatment solution. Furthermore, Nakagawa, Bulletin of Japan Association for Fire Science and Engineering, Vol. 66, No. 3, p. 41 (2016), states that using acetic acid in the intercalation compound reduces the expansion onset temperature of thermally expandable graphite to 160°C, and that adding sodium tetraborate as an auxiliary agent to the intercalation compound reduces the expansion onset temperature to 155°C. As shown above, the expansion onset temperature of thermally expandable graphite can be appropriately changed by changing the chemical processing details, such as the type of intercalation compound. This indicates that the value of the expansion onset temperature of thermally expandable graphite can be appropriately designed by changing the manufacturing method of the thermally expandable graphite.

[0030] As mentioned above, in order to achieve the object of the present invention, a thermally expandable graphite having an expansion onset temperature in the range of 175 to 200°C is selected for the resin composition of the present invention. According to the investigations of the present inventors, the use of a thermally expandable graphite having an expansion onset temperature in the above temperature range allows the resin composition of the present invention to achieve the intended performance. However, the measured values ​​of the expansion onset temperature of thermally expandable graphite currently exist as described below. In order to establish the present invention as an established technology, it is necessary to determine a measurement method, etc., to obtain an objective value for the expansion onset temperature, regardless of the brand name.

[0031] As mentioned above, there are no officially standardized methods for measuring and determining the expansion onset temperature of thermally expandable graphite. As explained below, manufacturers and users independently determine the expansion onset temperature based on their own in-house methods. For example, Japanese Patent Laid-Open Publication No. 2007-45676 defines the expansion onset temperature as the temperature at which thermally expandable graphite is placed in a graduated glass cylinder and its volume increases by 1.1 times at a heating rate of 5°C / min. Japanese Patent No. 4693615 also defines the expansion onset temperature as the temperature at which thermally expandable graphite is placed in a glass container, placed in an electric furnace set at a constant temperature, and removed every 20 minutes. The temperature at which the volumetric expansion ratio increases by 1.5 times is then defined as the expansion onset temperature. For example, the expansion onset temperature of GREP-EG (product name, manufactured by Tosoh Corporation) is listed as 230°C. In JP2020-514497A, the expansion onset temperature of expandable graphite is determined as the point at which the volume expands by 1% at a heating rate of 5°C / min in thermomechanical analysis. In Japanese Patent No. 7221733A, the expansion onset temperature is determined as the temperature at which normal force rises at a heating rate of 10°C / min using a rheometer. The expansion onset temperatures of the thermally expandable graphites EXP-50S120, EXP-50S150, and EXP-50S160 (all trade names) manufactured by Fuji Graphite Co., Ltd. and CAN60 (trade name) manufactured by Air Water Inc. are determined to be 120°C, 150°C, 160°C, and 220°C, respectively.

[0032] The applicant of Patent Document 2, previously cited as prior art, and Japanese Patent No. 4693615, which describes the measurement method and definition of the expansion onset temperature, are the same, but they state different expansion onset temperatures for the same brand name, "GREP-EG." Specifically, Patent Document 4693615 states that the expansion onset temperature of GREP-EG measured as described above is 230°C, while the aforementioned Patent Document 2 states that the expansion onset temperature is 220°C, a difference of 10°C. Furthermore, Patent Document 3832703, held by the same patentee as Patent Document 2, states that the expansion onset temperature of the same brand name, GREP-EG, is 200°C. As mentioned above, the expansion onset temperature of thermally expandable graphite varies depending on the intercalation compound. Therefore, it is inferred that the difference in these expansion onset temperatures is primarily due to differences in the manufacturing methods of thermally expandable graphite. This means that the expansion onset temperature cannot be determined solely by the product name. Furthermore, the measurement method and definition of the expansion onset temperature of thermally expandable graphite have not been standardized, and there are no official standards. Therefore, as mentioned above, each manufacturer has its own unique standards for the measurement method and definition of the expansion onset temperature of thermally expandable graphite. In other words, the expansion onset temperature attached to each brand name of thermally expandable graphite product is currently displayed as a numerical value without any consideration of objectivity. In response to this situation, as mentioned above, for example, the invention described in Patent Document 2 is characterized in that "the expansion onset temperature of the expandable graphite used in combination with the resin composition is lower than the decomposition onset temperature of the chlorinated polyvinyl chloride resin or polyvinyl chloride resin contained in the resin composition." For the invention described in Patent Document 2 having the above configuration, it is natural that the measurement method and definition of the expansion onset temperature of the thermally expandable graphite must be specified, the expansion onset temperature must be determined using the specified measurement method and definition, and the invention's technical evaluation must be performed. In contrast, Patent Document 2 does not describe the measurement method or definition.

[0033] As shown above, three publications by the same applicant disclose different expansion start temperatures for expandable graphite of the same brand name: 200°C, 220°C, and 230°C. As mentioned above, the expansion start temperature of expandable graphite can be appropriately designed depending on the manufacturing method of the expandable graphite. Therefore, the above facts indicate that each applicant is offering expandable graphite products under the same brand name that have expansion start temperatures that differ by as much as 30°C, from 200°C to 230°C, based on evaluations made according to their own company standards. Therefore, a person skilled in the art would fully understand that the value of the expansion onset temperature of thermal-expandable graphite can be varied as a design factor and cannot be identified by its brand name. Furthermore, it would be recognized as well-known technology that there is no standardized means or definition for measuring the expansion onset temperature of thermal-expandable graphite, and that the value of the expansion onset temperature is a non-objective value evaluated based on in-house standards. Therefore, the fact that the invention described in Patent Document 2, filed by a person skilled in the art, does not include any description of a method for determining the expansion onset temperature of thermal-expandable graphite directly leads to the inability to objectively identify the invention (technology), and is therefore inconceivable in the first place. Above all, the fact that the method for determining the "decomposition onset temperature of the resin component" and the "expansion onset temperature of thermal-expandable graphite," which are the main technical requirements and design factors constituting the invention described in Patent Document 2, is unknown makes it impossible for even a person skilled in the art to even consider the invention described in Patent Document 2.

[0034] In the present invention, the expansion onset temperature of the thermally expandable graphite constituting the resin composition is defined as "the temperature at which the volume of the thermally expandable graphite increases by 1.1 times when the thermally expandable graphite is heated at a heating rate of 10°C / min." As mentioned above, there is no standardized method for measuring the expansion onset temperature of the thermally expandable graphite constituting the present invention. On the other hand, as mentioned above, JIS K 7120 is generally used for thermogravimetry of resins, and the heating rate is 10°C / min. The thermal decomposition onset temperature of the resin, which can be determined by thermogravimetry, and the expansion onset temperature of the thermally expandable graphite vary in evaluation value depending on the method of providing heat to the sample to be measured (heating rate, heat transfer, etc.) and the evaluation criteria. In the present invention, as mentioned above, the thermal decomposition of the polyvinyl chloride resin constituting the resin composition is evaluated according to JIS K 7210, and therefore the heating rate of the thermally expandable graphite used in combination is also set to the same 10°C / min. The criterion for determining the start of expansion was a change in volume that can be easily determined visually, rather than by a mechanical method. As a result of the above, in the present invention, thermally expandable graphite was heated at a temperature increase rate of 10°C / min, and the temperature at which the volume of the thermally expandable graphite increased by 1.1 times was defined as the expansion start temperature of the thermally expandable graphite.

[0035] The inventors measured the expansion onset temperatures of various commercially available thermally expandable graphite products using the method specified above. Specifically, 5 g of a sample was placed in a 25 ml graduated cylinder and placed in a heating furnace. The sample was continuously heated at a heating rate of 10 °C / min without being removed, and the volume change was measured visually from outside the furnace. To ensure accurate sample temperature measurements, a thermocouple thermometer was placed as close as possible to the graduated cylinder. Table 1 summarizes the expansion onset temperatures of each thermally expandable graphite product measured as described above. Table 1 also lists the manufacturer's name, product name (brand name), and the expansion onset temperature listed by the manufacturer in the manufacturer's catalog for each thermally expandable graphite product used for measurement. Note that none of the manufacturers discloses the method for measuring the expansion onset temperature of their own products.

[0036] TIFF2026031005000001.tif107170

[0037] As shown in Table 1, the expansion onset temperatures of many commercially available thermally expandable graphite products were measured. When the results of the expansion onset temperatures measured using the method described above were compared with the expansion onset temperatures indicated by the manufacturers, as shown in Table 1, in some cases the values ​​obtained using the measurement method adopted in the present invention matched the values ​​indicated by the manufacturers, and in other cases the difference from the manufacturer's value was as small as 5% or less. As shown in Table 1, in most cases the difference was less than 10°C. However, in some cases the difference was greater than 10°C, or even greater than 20°C, indicating that different companies use different methods to measure the expansion onset temperatures.

[0038] Among the thermally expandable graphites listed in Table 1, "EXP-50S-150," "EXP-50S-160," and "953240L" (all trade names) were used. These graphites have an expansion onset temperature of approximately 160°C, as measured by the measurement method employed in the present invention. The expansion ratios were measured from the expansion onset temperature (i.e., an expansion ratio of 1.1) to temperatures around 230°C. Figure 1 shows the expansion ratio curves for the three types of graphite with expansion onset temperatures around 160°C. As shown in Figure 1, even though the expansion onset temperatures are nearly the same at approximately 160°C, the expansion behavior of the thermally expandable graphite, i.e., the rate of increase in the expansion ratio with heating temperature, differs depending on the type of thermally expandable graphite. That is, as shown in Figure 1, although the expansion onset temperatures of the three types of thermally expandable graphite are close to each other around 160°C, the expansion ratios vary as the temperature rises. This indicates that the expansion characteristics up to high temperatures cannot be predicted solely by the expansion onset temperature. For example, as shown in the expansion curve for "EXP-50S-160" in Figure 1, the weight loss when the expansion volume increased by about four times was about 7%.

[0039] From the thermally expandable graphites listed in Table 1, four types of thermally expandable graphite with varying expansion onset temperatures (120°C to 213°C) were used: "EXP-50S-120," which has an expansion onset temperature of 120°C according to the measurement method employed in this invention; "953240L," which has an expansion onset temperature of 160°C; "EXP-50S-160," which has an expansion onset temperature of approximately 162°C; and "CA-60N," which has an expansion onset temperature of 220°C (all trade names). The following study was conducted using these four types of thermally expandable graphite, and the results are summarized in Table 2. For each type of thermally expandable graphite, heated material (i.e., graphite contained in the "initial expansion material of a fire") was obtained after heating at 250°C for 5 minutes (a low-temperature heating range simulating the initial stage of a fire), and the weight loss rate (%) and expansion ratio of the heated material were measured. In addition, for each thermally expandable graphite, the heated graphite (i.e., the graphite contained in the "high-temperature thermally expandable body") was obtained after heating at 600°C for 5 minutes, and the weight loss rate (%) and expansion ratio of the obtained heated graphite were measured.

[0040] TIFF2026031005000002.tif64170

[0041] As shown in Table 2, a comparison of the weight loss rate of expandable graphite in the low-temperature range (heating at 250°C for 5 minutes) and the high-temperature range (heating at 600°C for 5 minutes) reveals that for all four types of expandable graphite with different expansion onset temperatures (120-213°C), a rapid weight loss of 68% to 86% occurs during heating in the low-temperature range. This indicates that the intercalation compound rapidly desorbs from the expandable graphite, which is a graphite intercalation compound, near the temperature above the expansion onset temperature. In contrast, the expansion ratio of expandable graphite during heating in the low-temperature range tends to increase to 72% of the final expanded product when heated at a low expansion onset temperature of 120°C. However, for expandable graphite with an expansion onset temperature of 160-213°C, expansion is suppressed to 11% to 26%. This indicates that a moderately expanded thermally expandable graphite body is formed that is suitable for filling gaps in fixtures and other items that are needed when heated in the low-temperature early stages of a fire.

[0042] As mentioned above, the resin composition of the present invention is characterized in that the thermal decomposition onset temperature of the polyvinyl chloride resin used in combination with thermally expandable graphite is lowered below 215°C, for example, the characteristic value listed in Patent Document 2, by using a specific dehydrochlorination catalyst with improved functionality. In addition, the resin composition of the present invention contains an amino group-containing compound and / or a phosphorus compound so that the "high-temperature thermally expandable body" has a high expansion ratio, a higher caking force, and better shape retention and mechanical strength.

[0043] The inventors believe that by configuring the resin composition of the present invention as described above, it has been possible to produce an inflatable body (heated object) at the early stage of a fire formed by heating at a low temperature of 250°C for 5 minutes, which has both the appropriate expansion and hardness to fill gaps in building materials, which are necessary when building materials are heated at the low temperature range at the early stage of a fire. It should be noted that, for example, it is not possible to obtain information about the rapid weight loss of thermally expandable graphite that occurs when a resin composition is heated at the low temperature range at the early stage of a fire, as described in Patent Document 2, from a heated object obtained by heating a resin composition containing thermally expandable graphite at a high temperature range of 600°C for 30 minutes, or about the specific properties of the inflatable body, such as the appropriate expansion ratio, shape collapse, and gel properties, which occur when the resin composition is heated at the low temperature range at the early stage of a fire.

[0044] The present inventors conducted extensive research to develop a resin composition that exhibits a moderate expansion ratio and moderate hardness (shape-loss) at low temperatures (specifically, 250°C) so that a "fire initial expansion body" can effectively suppress the spread of a fire in the early stages of a fire, and that also has "gel properties" that allow for efficient production of fire-resistant sheets, fire-resistant components, and the like. The present inventors discovered that by synthesizing palladium (Pd)-supported zinc (palladium-supported zinc) and using this as a catalyst to prepare a resin composition containing a polyvinyl chloride resin, the decomposition initiation temperature of the polyvinyl chloride resin can be further lowered compared to the invention described in Patent Document 1. Furthermore, the inventors discovered that the use of an amino group-containing compound and / or a phosphorus compound that suppress the catalytic function of the desalination catalyst allows the palladium-supported zinc to function effectively as a dehydrochlorination catalyst for the polyvinyl chloride resin. Furthermore, the inventors discovered that the remarkable effects of the present invention can be achieved by using thermally expandable graphite with an expansion initiation temperature in the range of 175°C to 200°C. The resin composition of the present invention containing these components produces an "initial stage of fire expansion" in the low temperature range (near 250°C) that exhibits more effective and useful properties for suppressing the spread of fire in the early stages of a fire, and the final "high temperature thermally expandable product" has a high expansion ratio, high caking power, and excellent shape retention and mechanical strength, making it an excellent fire spread suppressant.Furthermore, when the resin composition of the present invention is used as a raw material to produce products such as fire-resistant sheets and fire-resistant structural materials, it exhibits "gel properties" that allow for good production yields.

[0045] In the invention described in Patent Document 1, the inventors discovered an effective dehydrochlorination catalyst that, when added, decomposes (initiates dehydrochlorination) polyvinyl chloride resin at a temperature lower than the initial temperature at which the resin begins to thermally decompose. This enabled the provision of a polyvinyl chloride resin material that is particularly effective in suppressing the spread of fire in the early stages of a fire. They also discovered that zinc oxide, metallic zinc, and the like effectively function as dehydrochlorination catalysts for polyvinyl chloride resin. Compared to the prior art, the inventors discovered that in order to develop a resin composition that can be used to provide products such as fire-resistant sheets and fire-resistant components that can more effectively suppress the spread of fire in the early stages of a fire, it is necessary to use thermally expandable graphite that expands at a low expansion temperature of 175°C to 200°C. However, they discovered that this method poses the following problems. For example, when producing a fire-resistant sheet using a resin composition containing polyvinyl chloride resin and thermally expandable graphite, a temperature load of up to approximately 170°C is applied when the sol is gelled. When such a temperature load is applied, the sheet may expand due to the expansion of the thermally expandable graphite, and if the sheet expands, the number of defective products increases and the production yield decreases, which is a serious industrial problem. For this reason, it is important to provide a resin composition containing thermally expandable graphite with excellent "gelling properties" that can reduce the incidence of defective products caused by the expansion of the thermally expandable graphite, a constituent component, during production, in which a sol-like resin composition is gelled to produce a product.

[0046] In the course of investigating resin compositions that could provide products such as fire-resistant sheets and fire-resistant components that more effectively suppress the spread of fire in the early stages of a fire than conventional techniques, the inventors discovered that it is necessary to use thermally expandable graphite with an expansion onset temperature of 175°C to 200°C, which allows it to expand at a lower temperature than conventional graphite. Furthermore, they discovered that it is important to improve the thermal decomposition behavior of the polyvinyl chloride resin used in combination with the graphite at temperatures below 250°C, specifically, to lower the thermal decomposition (dehydrochlorination) temperature of the polyvinyl chloride resin. To achieve this, they discovered that a catalyst capable of further lowering the thermal decomposition (dehydrochlorination) temperature of the polyvinyl chloride resin is needed, replacing the zinc oxide or metallic zinc catalysts for polyvinyl chloride resins discovered in the invention described in Patent Document 1, as mentioned above.

[0047] After examining various substances, the present inventors have found that by adding metallic zinc supported on palladium (Pd) to polyvinyl chloride resin, the thermal decomposition (dehydrochlorination) temperature of polyvinyl chloride resin can be lowered when thermally expandable graphite with an expansion onset temperature in the range of 175°C to 200°C is used in combination, thereby realizing the object of the present invention. However, the reason why palladium-supported zinc functions as an effective catalyst for dehydrochlorination of polyvinyl chloride resin is not clear at this time.

[0048] The present inventors first investigated the effect of the presence or absence of a dehydrochlorination catalyst in a polyvinyl chloride resin on the weight loss of the resin composition when heated at various temperatures in the low temperature range. Using zinc oxide as an example of a dehydrochlorination catalyst, the inventors investigated the effect of adding zinc oxide. In the test, a sample was prepared using 100 parts by mass of polyvinyl chloride resin and 80 parts by mass of plasticizer (DOP). As an example of a catalyst, 5 parts by mass of zinc oxide was added to the basic composition. Sheets were prepared as described below to serve as measurement samples. The measurement samples were then heated at temperatures of 210°C, 230°C, and 250°C for 10 minutes, and the weights of the heated samples were measured at each temperature. The mass ratio of the heated sample to the original sample weight was then calculated as the residual ratio, and the weight loss rate was calculated and is shown in Table 3. As shown in Table 3, while the weight loss due to heating was small in systems without a catalyst, it was significant in systems with a catalyst.

[0049] TIFF2026031005000003.tif45170

[0050] Next, a similar test as shown in Table 3 was conducted using palladium-supported zinc (Pd) catalyst, in which palladium (Pd) was supported on metallic zinc instead of zinc oxide. Specifically, the basic composition consisted of 100 parts by mass of polyvinyl chloride resin and 80 parts by mass of plasticizer (DOP). A sample was prepared using 5 parts by mass of palladium-supported zinc catalyst (Zinc Powder, manufactured by Kokusan Chemical Co., Ltd.) with Pd loadings adjusted to 0.01%, 0.02%, 0.05%, 0.10%, or 0.15% (excluding %) relative to metallic zinc. Sheets were then prepared as described below and used as measurement samples. The residual ratio and weight loss rate of the measurement samples with the addition of the above-mentioned different catalysts were investigated by heating them for 10 minutes at three different temperatures, as previously described. The results are shown in Table 4. For comparison, the residual ratio and weight loss rate of the samples with the addition of zinc oxide catalyst shown in Table 3 are also shown in Table 4.

[0051] TIFF2026031005000004.tif66170

[0052] As shown in Table 4, the weight loss rate due to thermal decomposition of polyvinyl chloride resin was greater in the case of using palladium-supported zinc as a catalyst than in the case of using zinc oxide as a catalyst. Based on the results in Table 4, the fact that the dehydrochlorination catalyst shifts the decomposition onset temperature of polyvinyl chloride resin to a lower temperature as explained above, and the high weight loss rate of the heated thermally expandable graphite (i.e., the graphite contained in the "initial stage of a fire") after heating at 250°C for 5 minutes (a low-temperature heating range simulating the early stage of a fire) as shown in Table 2, the inventors believe that the reason why the "initial stage of a fire" formed at 250°C, which simulates the earlier early stage of a fire, from the resin composition of the present invention exhibited a moderate expansion ratio and moderate hardness ("shape retention") that are more effective in suppressing and preventing the spread of fire in the early stage of a fire is as follows. When the resin composition of the present invention is heated at 250°C, the low temperature range of 250°C that simulates the early stage of a fire is reached. The presence of a dehydrochlorination catalyst shifts the decomposition temperature of the polyvinyl chloride resin to a lower temperature. This shifts the temperature to a lower level, approximately 250°C, relative to the resin's thermal decomposition temperature. This results in the appearance of a combustion residue phase with increased hardness due to the thermal decomposition of the polyvinyl chloride resin at a temperature relatively low (up to 250°C) below the resin's thermal decomposition temperature. Furthermore, the presence of a catalyst in the resin composition results in a significant weight loss of the thermally expandable graphite shown in Table 2, which is superimposed on the weight loss of the polyvinyl chloride resin shown in Table 4. Furthermore, as shown in Table 2, the thermally expandable graphite coexisting with the polyvinyl chloride resin undergoes significant expansion in the above temperature range. These factors combine to form an "initial fire expansion body" that effectively prevents the passage of fire and smoke in the early stages of a fire.

[0053] There are many examples of palladium being supported on various metals and used as a catalyst. For example, in "Yanagisawa: Japan Chemical Journal, No. 10, p. 1690 (1975)," a palladium salt solution was adsorbed on various supports, and then reduced with hydrogen or the like to convert it into palladium, and the catalytic function of the resulting palladium was examined. In the present invention, palladium was synthesized as a simple substance and supported on metallic zinc, and its effectiveness as a catalyst for the thermal decomposition of polyvinyl chloride resin was examined. The synthesis method of a palladium colloidal dispersion for supporting palladium on metallic zinc and the procedure for supporting palladium are described in the Examples.

[0054] As explained above, the catalytic effect on the thermal decomposition of polyvinyl chloride resin was investigated using the same amount of zinc metal with gradually varying amounts of palladium supported in the range of 0.01 to 0.15% relative to the mass of the zinc metal. As shown in Table 4 above, it was confirmed that the catalytic effect of palladium-supported zinc on the thermal decomposition of polyvinyl chloride resin did not change significantly when the palladium support amount was between 0.05% and 0.10%. Therefore, in the present invention, various tests were conducted with the support amount fixed at 0.05%, as described below. Furthermore, since Patent Document 1, cited as prior art, claims that zinc oxide is highly effective as a dehydrochlorination catalyst in the thermal decomposition of polyvinyl chloride resin, in the present invention, a catalyst-free sample and zinc oxide were used for comparison with palladium-supported zinc.

[0055] As mentioned above, the applicants of the present application have discovered amino group-containing compounds and / or phosphorus compounds that have the function of suppressing the catalytic function of dechlorination catalysts, and have developed a technology that uses these compounds to provide a thermally expandable vinyl chloride resin material that not only has excellent shielding properties at low temperatures, but also has an expandable body that expands upon heating at a high temperature of 800°C, has a high expansion ratio, exhibits greater caking power, is excellent in shape retention and mechanical strength, and can more effectively block flames and smoke from low temperatures. The inventors' investigations have shown that the above technology can also be effectively utilized in the resin composition of the present invention. For this reason, the resin composition of the present invention is required to contain 50 parts by mass or more and 150 parts by mass or less of thermally expandable graphite having an expansion onset temperature of 175°C to 200°C, and further contain 10 parts by mass or more and 30 parts by mass or less of an amino group-containing compound and / or a phosphorus compound, per 100 parts by mass of polyvinyl chloride resin, and is characterized by containing 2.5 parts by mass or more and 10 parts by mass or less of palladium-supported zinc, which is palladium-supported zinc that is more effective as a dehydrochlorination catalyst for polyvinyl chloride resin as described above.

[0056] Examples of the amino group-containing compound and / or phosphorus compound constituting the present invention include at least one selected from the group consisting of melamine cyanurate, melamine polyphosphate, melamine-melam-melem polyphosphate, melamine phosphate, melamine polyphosphate metal salt, piperazine phosphate, ethylenediamine phosphate, melamine sulfate, melamine, melem, benzoguanamine, melamine-coated ammonium polyphosphate, silane-coated ammonium polyphosphate, ethylenediamine polyphosphate metal salt, ammonium polyphosphate, and spirocyclic diphosphonates.

[0057] In addition to the components listed above, the resin composition of the present invention may contain a plasticizer as needed. While the amount of plasticizer used is not particularly limited, a range of approximately 40 to 150 parts by mass per 100 parts by mass of polyvinyl chloride resin is appropriate. While there are no limitations on the type of plasticizer, phthalate esters, particularly dioctyl phthalate, are most suitable. Other plasticizers with specific functions other than plasticization, such as tricresyl phosphate for imparting flame retardancy, dioctyl adipate for imparting low-temperature properties, and soybean oil-based plasticizers for anti-aging, can also be used.

[0058] In addition to the components listed above, the resin composition of the present invention may contain, as needed, common inorganic fillers, various colorants, heat and light antioxidants, lubricants, anti-blocking agents, flame retardants, etc., provided that the object of the present invention is not impaired. Flame retardants that can be used include inorganic hydroxide-based flame retardants, phosphorus-based flame retardants, halogen-based flame retardants, and antimony-based flame retardants. To improve mechanical properties, crosslinkers such as polyethyleneimine, polyisocyanate, and epoxy may also be used.

[0059] The method for producing a fire-resistant sheet from the resin composition of the present invention is not particularly limited, and any known method may be used. When producing a fire-resistant sheet, a woven fabric, a nonwoven fabric, a resin sheet, or the like may be attached to one or both sides of a sheet to form a laminate. The woven fabric and nonwoven fabric used in this case may be, for example, an organic fiber such as polyester, or an inorganic fiber such as glass fiber or carbon fiber. The thickness and density, weaving method, surface treatment, etc. of the woven fabric and nonwoven fabric, and the material of the resin sheet are not limited as long as the object of the present invention is not impaired. To provide a reinforcing effect for a fire-resistant sheet or fire-resistant member produced from the resin composition of the present invention, the above-mentioned woven fabric, nonwoven fabric, or resin sheet may be embedded within the layer of the fire-resistant sheet.

[0060] Furthermore, when a fire-resistant sheet is produced from the resin composition of the present invention, a pressure-sensitive adhesive layer may be provided on one or both sides of the sheet. In this case, if a laminate is previously formed from the woven fabric, nonwoven fabric, and resin sheet as described above, the pressure-sensitive adhesive layer may be provided on the laminate.

[0061] A sheet can be produced from the resin composition of the present invention by a general method for producing a polyvinyl chloride resin sheet. For example, any of the following methods may be used: a method in which the essential components and optional components are uniformly mixed in advance, and the resin composition is melted in an extruder and passed through a die to produce a sheet; a method in which the resin composition is kneaded using a calendar to produce a sheet; or a method in which the resin composition is coated on a substrate and gelled by heating to produce a sheet. In any of these methods, however, the thermally expandable graphite constituting the resin composition of the present invention has an expansion onset temperature of 175°C to 200°C, and therefore, production is preferably carried out under operating conditions below the temperature at which the thermally expandable graphite begins to expand. [Example]

[0062] Next, the present invention will be described in detail with reference to examples and comparative examples. First, a method for preparing palladium-supported zinc constituting the resin composition of the present invention and a method for producing a fire-resistant sheet from the resin composition of the present invention will be described. All raw materials used in the present invention that do not have a manufacturer's name listed were reagent products manufactured by Wako Pure Chemical Industries, Ltd., and were used as they were.

[0063] [Preparation of palladium colloidal solution and method for supporting it on metallic zinc] 1.5 g of palladium acetate and 3 g of a 40% aqueous solution of maleic acid-modified resin, synthesized as described below and functioning as a palladium dispersant, were dissolved in 300 g of denatured ethanol (product name: Neoethanol PM, manufactured by Ohara Chemical Paint Co., Ltd.). A previously prepared solution of 1.5 g of hydrazine dissolved in 40 g of denatured ethanol was added dropwise to this solution. After the dropwise addition, stirring was continued for 8 hours at room temperature, resulting in a black, transparent colloidal solution containing approximately 0.2% palladium. The resulting colloidal solution was mixed to achieve the desired ratio (amount) of palladium when loaded onto zinc. Residual hydrazine, acetic acid, denatured ethanol, etc. were evaporated at 80°C to 100°C for 24 hours to obtain palladium-loaded zinc. The particle size of palladium in the colloidal dispersion was measured using a particle analyzer (product name: FPAR-1000S, manufactured by Otsuka Electronics Co., Ltd.) and found to be 100 nm to 300 nm.

[0064] A polyether-modified styrene-maleic anhydride copolymer (maleic acid-modified resin) is an effective dispersant for dispersing palladium. A method for producing such a dispersant is described in detail in Japanese Patent No. 5118150. Specifically, the dispersant is obtained by first reacting maleic anhydride with a polyoxide having an alcohol group at the end, then copolymerizing it with a styrene monomer, and then salifying the remaining carboxylic acid with an amine. The palladium-supported zinc used in the examples of the present invention was prepared by preparing a palladium-containing colloidal solution using a 40% aqueous solution of the copolymer obtained as described above, and then supporting palladium on zinc.

[0065] [How to make fireproof sheets] The fire-resistant sheets of the examples and comparative examples of the present invention were prepared by gelling a sol layer formed by coating each resin composition. Specifically, a sol-like resin composition containing pre-blended components was coated onto release paper using a comma coater to a thickness of 1.3 mm, and then heated in a hot air oven at 140-170°C for 20 minutes to form a sheet. However, in the case of a resin composition containing graphite with an extremely low expansion initiation temperature, such as 120°C, the sheet was prepared by heating for a long period of time at 110-120°C.

[0066] As explained above, the decomposition temperature of the polyvinyl chloride resin constituting the resin composition of the present invention can be lowered by using a dehydrochlorination catalyst. This point will be explained again. [Study on the decomposition temperature of polyvinyl chloride resin] As mentioned above, Ryuron Paste 772A (product name: Tosoh Corporation, degree of polymerization: 1650) was used as an example of PVC. Three types of samples were measured for the resin decomposition onset temperature at a heating rate of 10°C / min in accordance with JIS K 7120: this PVC sample, a sample in which 5 parts by weight of palladium-loaded zinc (0.05% palladium) was added to 100 parts by weight of PVC, and a comparative sample to which zinc oxide was added. The results confirmed the following: For the PVC-only sample, the onset of decomposition was 200°C, evaluated as the point at which the weight had decreased by 0.5%. In contrast, for the sample with palladium-loaded zinc added, the onset of decomposition was 173°C, evaluated as the point at which the weight had decreased by 0.5%. This confirmed that the addition of palladium-loaded zinc effectively functions as a dehydrochlorination catalyst and can lower the onset of PVC decomposition temperature. In addition, in the sample in which 5 parts by mass of zinc oxide was added to 100 parts by mass of PVC, the decomposition onset temperature was evaluated as 179°C when the weight had decreased by 0.5%. Although this was inferior to the case in which palladium-supported zinc was added, the PVC decomposition onset temperature was also lower.

[0067] From the above measurement results, in the present invention, the decomposition onset temperature of polyvinyl chloride resins was evaluated by measuring the weight loss caused by thermal decomposition of the resin at a heating rate of 10°C / min in accordance with JIS K 7120, a standardized method for thermogravimetric measurement of resins, and the temperature at which the weight (mass) decreased by 0.5% was determined to be the thermal decomposition onset temperature of the resin.

[0068] [About the palladium-supported zinc used] As described above, the palladium-supported zinc constituting the resin composition of the present invention functions effectively as a dehydrochlorination catalyst for polyvinyl chloride resins, thereby lowering the decomposition onset temperature of polyvinyl chloride resins. As shown in Table 4 above, the catalyst's effect on the weight loss rate of polyvinyl chloride resins at low temperatures is extremely significant, but the effect is nearly saturated at palladium loadings of 0.05 to 0.10%. For this reason, in the examples, palladium-supported zinc with a palladium loading of 0.05% was used. The amount of palladium-supported zinc added is preferably within the range of 2 to 10 parts by mass per 100 parts by mass of polyvinyl chloride resin. In the examples of the present invention, a fixed amount of 5 parts by mass was used.

[0069] [Measurement of the expansion start temperature of the thermally expandable graphite used] The expansion onset temperature of the thermally expandable graphite used in the study was measured by the following method. 5 g of the sample was placed in a 25 ml measuring cylinder and placed in a heating furnace. Without removing the sample, it was continuously heated at a temperature increase rate of 10°C / min, and the volume change was measured visually from outside the heating furnace. In the present invention, the temperature at which the volume of the thermally expandable graphite increased by 1.1 times was defined as the expansion onset temperature of the thermally expandable graphite. During the above measurement, the thermocouple thermometer was placed as close as possible to the measuring cylinder to ensure accuracy of the sample temperature. The brands and manufacturers of the thermally expandable graphite used in the study examples are listed in Table 1.

[0070] [Examples 1 to 8, Comparative Examples 1 to 17] (Preparation of Resin Composition) The polyvinyl chloride resin used was Ryuron Paste 772A (product name: Tosoh Corporation, average degree of polymerization: 1650), and the plasticizer used was an odorless phthalate ester-based plasticizer, DOP-MS (product name: J-Plus Co., Ltd.). The basic composition consisted of 100 parts by mass of the polyvinyl chloride resin, 80 parts by mass of plasticizer (DOP), 5.0 parts by mass of palladium-loaded zinc with a palladium loading of 0.05%, and 18 parts by mass of melamine cyanurate (product name: MC4000, Nissan Chemical Co., Ltd.), an amino group-containing compound. Resin compositions for the Examples and Comparative Examples were prepared using this basic composition and 75 parts by mass of thermally expandable graphite with different expansion onset temperatures. The expansion onset temperatures of the thermally expandable graphites used were measured as described above. The formulations of the resin compositions for the Examples and Comparative Examples, the expansion onset temperatures of the thermally expandable graphites measured above, and the evaluation results described below are summarized in Table 5 for the Examples and Tables 6-1 to 6-3 for the Comparative Examples.

[0071] (Preparation of fireproof sheet) Using each of the resin compositions of the Examples and Comparative Examples obtained above, fire-resistant sheets were produced by gelling the sol layer formed by coating using each resin composition using the fire-resistant sheet production method described above.

[0072] (evaluation) The following evaluations were carried out for each of the resin compositions of the Examples and Comparative Examples using fire-resistant sheets produced using the resin compositions of the Examples and Comparative Examples. The evaluation results are summarized in Table 5 for the Examples and Tables 6-1 to 6-3 for the Comparative Examples.

[0073] <Expansion characteristics of "fire initial expansion body" formed from resin composition> <Expansion ratio> Using the resin compositions of the formulations listed in Table 5 or Tables 6-1 to 6-3, fire-resistant sheets obtained by the fire-resistant sheet preparation method described above were prepared into test pieces measuring 35 mm × 20 mm in plan view and 1.3 mm in thickness. The test pieces were then evaluated for expansion properties using the following method. An aluminum plate was placed at the bottom of an aluminum container (1 mm thick) with plan views of 36 mm × 21 mm and a height of 50 mm, open at the top and bottom, and the test piece was placed on top of the aluminum plate. The test piece was then inserted into a 250°C heating furnace and heated for 10 minutes. After heating, the test piece was allowed to cool to room temperature. The initial expansion mass of the fire was removed from the container and its height was measured. The expansion ratio relative to the thickness before heating was calculated and reported in the table as the expansion ratio. When the height of the initial expansion mass of the fire was not constant, measurements were taken at multiple locations and the average value was calculated. An expansion ratio of 5.5 times or greater was considered acceptable.

[0074] ≪Shape deformability≫ Next, a weight was placed on an aluminum plate measuring 50 mm x 25 mm in plan view, adjusting the total weight to 100 g. This aluminum plate was gently placed on top of the initial fire expansion object obtained by heating at 250°C for 10 minutes as described above, and left to stand for 10 seconds. If the initial fire expansion object did not lose its shape after standing, it was deemed a pass and indicated with a ○ in the table, and if it did break down, it was deemed a fail and indicated with an ×.

[0075] <Residual ratio (reference value)> In Table 5 or Tables 6-1 to 6-3, the weight of the initial expansion body used in the evaluation was measured, and the weight of the test piece heated at 250°C for 10 minutes was calculated to determine the ratio (%) of the weight to the weight of the test piece before the heating test. This value is shown as the residual ratio (the reciprocal of the weight loss rate) for reference. In other words, a larger value of the residual ratio means a smaller weight loss rate in the low temperature range and less morphological change.

[0076] <Gel properties of resin composition> According to the inventors' investigations, when a resin composition containing thermally expandable graphite is converted from a sol to a gel in the previously described fire-resistant sheet preparation method, a maximum temperature load of approximately 170°C is applied. To ensure a high yield in fire-resistant sheet production, it is necessary to prevent the thermally expandable graphite from starting to expand at this temperature. In the evaluation of the resin composition of the present invention, a sheet produced without expansion was deemed a pass and indicated by a circle in the table. A sheet produced that expanded was deemed a fail and indicated by an x ​​in the table. In the present invention, not only a single thermally expandable graphite was used in the test examples, but also a blend system using multiple types of thermally expandable graphite was investigated and evaluated. According to the inventors' investigations, even when the blend components contained expandable graphite that expands at temperatures below the gel temperature, the produced fire-resistant sheet sometimes did not substantially expand. In such cases, the composition was rated as a pass. When the inventors observed the initial expansion body of a fire-resistant sheet that had been evaluated as passing, even though it contained thermally expandable graphite that expands at temperatures below the gel temperature, they found that although whiskers had formed, the sheet had not expanded.

[0077] TIFF2026031005000005.tif169170

[0078] Table 6-1 shows the evaluation results of comparative resin compositions that use thermally expandable graphite whose expansion starting temperature is outside the range specified in the present invention. TIFF2026031005000006.tif158170

[0079] Tables 6-2 and 6-3 show the evaluation results of the resin compositions of the comparative examples that did not use palladium-supported zinc. TIFF2026031005000007.tif157170

[0080] TIFF2026031005000008.tif127170

[0081] <Expansion characteristics of "high-temperature thermal expandable body" formed from resin composition> Using the resin compositions of Examples 2 and 3 with the formulations shown in Table 5 as representative examples, test pieces with planar dimensions of 20 mm × 20 mm and a thickness of 1.3 mm were prepared from each fire-resistant sheet prepared by the method described above. An aluminum plate was placed at the bottom of an aluminum container with planar dimensions of 21 mm × 21 mm, open at the top and bottom, and a thickness of 1 mm, and the test piece obtained above was placed on the aluminum plate and heated at 800°C to obtain a "high-temperature thermally expandable body."

[0082] The "high-temperature-expandable solid" thus obtained was measured for its expansion ratio and caking force using the following methods. Specifically, for the expansion ratio, after heating and allowing it to cool to room temperature, the "high-temperature-expandable solid" was removed from the container and its height was measured, and the expansion ratio was calculated by comparing the height with the thickness before heating. When the height of the expanded solid was not constant, measurements were taken at multiple locations and the average value was calculated. For the caking force, a smooth plate was placed on top of the "high-temperature-expandable solid" obtained after the test, and the plate was pressed down with a compression testing machine. The maximum resistance force measured when the plate was positioned 8 mm above the bottom was expressed in kgf.

[0083] As a result of the above tests, it was confirmed that the "high-temperature thermally expandable body" obtained by heating the resin composition of Example 2 had an expansion ratio of 29, and the "high-temperature thermally expandable body" obtained by heating the resin composition of Example 3 had an expansion ratio of 27, both of which exhibited high expansion ratios. In addition, the "high-temperature thermally expandable body" obtained by heating the resin compositions of Examples 2 and 3 both had a binding strength of 2.6 kgf, confirming that they exhibited high binding strength and excellent shape retention.

[0084] [Overall Judgment] As a result of the above evaluation tests, products that passed the expansion ratio and shape collapse of the thermally expandable body, as well as the gel properties test when fabricated into fire-resistant sheets, were judged to be overall acceptable, and are indicated by ○ (pass) or × (fail) in Tables 5 and 6-1 to 6-3. As shown in Tables 5 and 6-1 to 6-3, the "fire initial expansion bodies" formed in the low-temperature range of a 250°C heating furnace exhibited an expansion ratio of 5.5 times or more, which is effective in suppressing and preventing the spread of fire in the early stages of a fire, and shape collapse properties (shape collapse properties) with good hardness suitable for filling gaps as described above. Furthermore, the composition that showed good results in the gel properties that are important when fabricating fire-resistant sheets was a resin composition that used palladium-loaded zinc in a polyvinyl chloride resin and contained thermally expandable graphite with an initial expansion temperature of 175°C to 200°C. In addition, the "high-temperature thermal expansion body" formed by heating the test piece at 800°C for 5 minutes had a high expansion ratio, a large adhesive force of 2.6 kgf, and excellent shape retention, making it suitable for fire suppression and fire prevention.

Claims

1. A resin composition comprising, per 100 parts by mass of a polyvinyl chloride resin, 50 parts by mass or more and 150 parts by mass or less of thermally expandable graphite having an expansion onset temperature of 175°C to 200°C, 10 parts by mass or more and 30 parts by mass or less of an amino group-containing compound and / or a phosphorus compound, and 2.5 parts by mass or more and 10 parts by mass or less of palladium-supported zinc.

2. 2. The resin composition according to claim 1, wherein the amount of palladium carried on the palladium-supported zinc is in the range of 0.01% by mass or more and 0.15% by mass relative to 100% by mass of the zinc.

3. 2. The resin composition according to claim 1, wherein the phosphorus compound and / or amino group-containing compound is at least one selected from the group consisting of melamine cyanurate, melamine polyphosphate, melamine-melam-melem polyphosphate, melamine phosphate, melamine polyphosphate metal salt, piperazine phosphate, ethylenediamine phosphate, melamine sulfate, melamine, melem, benzoguanamine, melamine-coated ammonium polyphosphate, silane-coated ammonium polyphosphate, ethylenediamine polyphosphate metal salt, ammonium polyphosphate, and spirocyclic diphosphonates.

4. 2. The resin composition according to claim 1, which is in the form of a fire-resistant sheet.

5. 2. The resin composition according to claim 1, wherein the expansion initiation temperature is the temperature at which the volume of the thermally expandable graphite increases by 1.1 times when the thermally expandable graphite is heated at a temperature increase rate of 10°C / min.

6. A fire-resistant member comprising the resin composition according to any one of claims 1 to 5.

7. A fitting comprising the fire-resistant member according to claim 6.

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