JP2021066830A - Resin composition, thermally-expandable sheet-like or putty-like refractory product, and manufacturing method of resin composition - Google Patents

Abstract

To provide a modification technique of new thermally-expandable graphite which enables a more excellent fire spread prevention effect at fire to be expected in a refractory product formed by using a resin composition containing thermally-expandable graphite and resin components, and is simple, excellent in economical efficiency, and highly practicable.SOLUTION: A resin composition contains modified expandable graphite and resin components. The resin composition is such that: 5-300 pts.mass of the modified expandable graphite is contained on the basis of 100 pts.mass of the resin components; a bulk volume ratio of the modified expandable graphite is increased to 1.05-3.0 times of a bulk volume of a raw material before heating by previously heat-treating a thermally-expandable graphite raw material; and polyisocyanate is added to the heat-treated thermally-expandable graphite in a state that the bulk volume is increased. A thermally-expandable sheet-like or putty-like refractory product, and a manufacturing method of the resin composition are also provided.SELECTED DRAWING: None

Description

In the present invention, in a resin composition containing heat-expandable graphite, improvement of expansion characteristics during combustion of a product formed by the resin composition during combustion is achieved by modifying the heat-expandable graphite which is a component of the resin composition. The present invention relates to a resin composition, a heat-expandable sheet-like or putty-like fireproof product, and a method for producing the resin composition.

It is already known that by blending heat-expandable graphite with a resin composition, the resin composition has a property of expanding during combustion. Utilizing this property, a sheet-shaped molded body is obtained from a resin composition containing heat-expandable graphite, and the molded body is attached to parts of fittings or the like, which is expected to have a fire spread prevention effect in the event of a fire. Various products such as sheets are offered. It is also used for finishing a resin composition containing heat-expandable graphite into a putty-like product and inserting it into a gap between the outside and the inside of a house or the like to prevent the passage of fire. The maximum performance of the heat-expandable graphite expected for these applications is the expansion characteristics during combustion of the product obtained by the resin composition containing the heat-expandable graphite.

Normally, the temperature at the time of fire is 500 ° C. or higher, so that most of the resin components and other organic substances constituting the resin composition are burned out. Then, a very small amount of carbide, phosphorus compound, and nitrogen compound are compounded to form an expanded residue (expansion body). The shape of this residue (expansion body), especially its volume, is an extremely important factor in preventing the spread of fire and the passage of fire. That is, it is an expansion characteristic that is habitually (generally) required for products in this field.

However, thermal expansion means an increase in volume, and it is extremely difficult to evaluate this property in the open state. That is, it is extremely difficult to evaluate the expansion characteristics of products such as sheet-shaped molded products and putties obtained by using the resin composition in an open state without spatial restrictions. The reason is that when thermal expansion is performed in the open state, the inflatable body becomes an amorphous mass, and accurate volume measurement cannot be performed.

Therefore, as a method for measuring expansion characteristics often used in this field, for example, there are the following methods. A sheet of the molded product to be evaluated is placed on the bottom of an upward open type container in which the bottom is closed in four directions and only the upper side is open, and combustion is performed in an electric furnace at 500 ° C. to 600 ° C. for a predetermined time. After cooling, the residue (expansion body) is taken out from the container, and the increase in volume is examined and evaluated. The evaluation method is generally obtained from the ratio of the thickness of the molded product to be evaluated before the test to the height after combustion. In this case, the specific gravity of the molded product to be evaluated, that is, the weight (mass) is out of consideration. As another evaluation method, the thickness of the molded product to be evaluated placed on the bottom of the container is made as uniform as possible, but the evaluation standard is to keep the weight before the test constant and to obtain the height of the expanded body. In some cases, the increase in volume due to the difference in height may be evaluated. The difference between the two viewpoints is that the ratio of the volume of the molded body to be evaluated before the test and the volume of the residue (expansion body) is evaluated based on the thickness, or the evaluation target is subjected to the test. The point is whether to emphasize the comparison of the volume of the expanded body based on the same mass of the molded body.

In particular, the specific gravity of a resin composition that can be used for various materials varies greatly depending on its composition. For example, the specific gravities of the vinyl chloride-based resin and the olefin-based resin are significantly different. Therefore, in the present invention, the thermal expansion characteristics of the molded product to be evaluated were evaluated by the following method.

A container obtained under predetermined heating conditions in which a molded body such as a sheet to be evaluated is placed in an amount having a constant weight on the bottom of an upward open type container in which the four directions and the bottom are closed as described above. The expansion characteristics of the resin composition used for forming the molded body to be evaluated were evaluated by comparing the volumes of the expanded bodies taken out from the above. Therefore, the unit of the measured value is expressed as ml / g. For example, the mass of the molded product (resin composition) to be evaluated before the heating test was 1.48 g, the bottom dimension of the container was 21 mm × 46 mm, and the height was 50 mm, which was obtained after heating. If the measured value of the height of the inflator is 34 mm, the expansion ratio is 22.2 ml / g as calculated by the following formula.
(2.1 x 4.6 x 3.4) /1.48=22.2 ml / g

The largest factor that gives the expansion coefficient depends on the heat-expandable graphite that constitutes the resin composition. Commercially available heat-expandable graphite is mainly composed of graphite and thermally decomposed graphite raw materials mined as natural products. After cleaning and crushing, inorganic acids such as sulfuric acid and nitric acid and oxidizing agents such as perchloric acid and hydrogen peroxide are used. The acid is inserted between the layers of graphite by processing with. The six-membered ring of graphite is partially cationized by the oxidizing agent, and the anion of the acid root is coordinated to this cation. This inserted substance is called intercalate, and it is rapidly gasified by heating to cause volume expansion. The type and amount of this intercalating substance is a major factor. For this reason, the characteristic display of commercially available heat-expandable graphite describes the volume expansion start temperature and the amount of gas. In addition, the range of particle size is also described from the aspect of manufacturing the resin composition. It is well known that even if the composition of the heat-expandable graphite is exactly the same, different particle sizes have a large effect on the expansion ratio. Generally, the larger the particle size, the larger the expansion ratio. The particle size may be expressed as the particle size.

Depending on the purpose and application of the product such as a molded product or putty obtained from the resin composition containing the heat-expandable graphite, the expansion start temperature at the time of fire may be regarded as important. For example, if expansion needs to occur in the early stages of a fire, the expansion initiation temperature must be lowered. For such a purpose, it is said that a low-molecular-weight organic acid or the like is a good intercalate substance in order to lower the gasification temperature (see Non-Patent Document 1). There is also a document that the expansion start temperature of thermally expandable graphite can be lowered to 200 ° C. or lower by treating graphite with concentrated sulfuric acid to which ammonium peroxosulfate and hydrogen peroxide are added (see Patent Document 1).

On the other hand, when the melting temperature of the resin component used in producing the resin composition is high, the expansion start temperature of the heat-expandable graphite contained must be higher than the melting temperature. Patent Document 2 states that, for this purpose, if 100 parts of the polymer contains an alkaline earth metal compound at a ratio of 5 to 30% by weight, the expansion start temperature can be raised to 300 ° C. or higher. .. Further, Patent Document 3 states that heat-expandable graphite having a high expansion start temperature of 260 ° C. or higher can be obtained by treating with an oxidizing agent containing hydrogen peroxide. For the same purpose, Patent Document 4 states that the expansion start temperature can be raised to 250 ° C. or higher by adding phosphoric acid to the reaction solution of sulfuric acid and an oxidizing agent.

Japanese Unexamined Patent Publication No. 11-268908 Japanese Unexamined Patent Publication No. 2007-63434 Japanese Unexamined Patent Publication No. 2012-193053 Japanese Unexamined Patent Publication No. 10-33010

Journal of Carbon Materials Society, Review Article, Masahiro Toyoda, "Expanded Graphite and Its Applications", 2008 [No. 233], page 160

However, all of these documents point to changes in the expansion start temperature of thermally expandable graphite, and this point is a technical issue. On the other hand, prior literature on an increase in the expansion volume of a molded product obtained from a resin composition containing the heat-expandable graphite, which is also an important property of the heat-expandable graphite, that is, an increase in the expansion property which is a problem of the present invention. Has not been found.

Generally, the factors for increasing the expansion characteristics are the type and amount of the substance intercalated between the layers of the heat-expandable graphite used as the raw material of the resin composition, and the intercalation. The volume of gas per unit mass of a substance.

Another factor related to the increase in expansion characteristics is considered to be the correlation between the release process of the gas generated by heating and the progress of combustion carbonization of the resin composition. That is, in order to achieve the increase in the expansion characteristics, which is the subject of the present invention, combustion carbonization proceeds while holding the gas generated by combustion from the molded product obtained from the resin composition containing the thermally expandable graphite as much as possible. Is considered desirable. As described in Japanese Patent No. 5992589 and Japanese Patent No. 6228658 proposed by the applicants of the present application, for example, when a vinyl chloride resin is used as a resin component, the vinyl chloride resin loses the plasticizer by combustion. While solidifying while solidifying, the chlorine and hydrogen of the vinyl chloride resin undergo a dehydrochlorination reaction to crosslink and carbonize. Therefore, in order to achieve an increase in expansion characteristics, these changes and the gas generation process are required. It is considered to be an important factor.

In the present invention, in a resin composition containing expandable graphite and a resin component, the heat-expandable graphite constituting the resin composition, which is expected to have a fire spread prevention effect in the event of a fire obtained by using the resin composition, can be used. It is an object of the present invention to realize the improvement of the expansion characteristics of the above-mentioned product by reforming. An object of the present invention is to modify heat-expandable graphite by a simple method, and to use a resin composition containing the heat-expandable graphite and a resin component, various kinds expected to have an excellent fire spread prevention effect in the event of a fire. By configuring the above products, it is possible to provide fire-resistant products with improved expansion characteristics compared to conventional products. The main technical problem of the present invention is that a refractory product formed by using a resin composition containing modified expansive graphite and a resin component can be expected to have a better fire spread prevention effect in the event of a fire. This is to provide a novel technology for modifying heat-expandable graphite, which is simple, has excellent economic efficiency, and is highly practical.

The above object is achieved by the following invention. That is, the present invention provides the following resin compositions.
[1] A resin composition containing modified expansive graphite and a resin component.
Based on 100 parts by mass of the resin component, the modified expandable graphite is contained in an amount of 5 to 300 parts by mass.
By heat-treating the heat-expandable graphite raw material in advance with the modified expandable graphite, the bulk volume ratio obtained by the following formula is 1.05 to 3.0 as compared with the bulk volume of the raw material before heating. A resin composition characterized by having polyisosianate added to heat-expandable graphite in a state where the volume has been doubled and the volume of heat-treated bulk has increased.
Volume magnification = Volume of heat-expandable graphite after heating / Volume of heat-expandable graphite raw material before heating

Preferred forms of the above-mentioned resin composition include those having the following configurations.
[2] The resin according to the above [1], wherein the modified expandable graphite particles have a maximum length in the range of 100 to 1000 μm and a maximum thickness in the range of 5 to 150 μm. Composition.
[3] The resin composition according to the above [1] or [2], wherein the resin component is any resin selected from a thermoplastic resin and a thermosetting resin.

The present invention also provides the following heat-expandable sheet-like or putty-like refractory products.
[4] A heat-expandable sheet-like or putty-like refractory product, which is a molded product composed of a resin composition containing modified expandable graphite and a resin component.
Based on 100 parts by mass of the resin component, the modified expandable graphite is contained in an amount of 5 to 300 parts by mass.
By heat-treating the heat-expandable graphite raw material in advance with the modified expandable graphite, the bulk volume ratio obtained by the following formula is 1.05 to 3.0 as compared with the bulk volume of the raw material before heating. A heat-expandable sheet or putty characterized by having polyisosianate added to the heat-expandable graphite in a state where the volume of heat-treated bulk has increased by a factor of two. Fireproof product.
Volume magnification = Volume of heat-expandable graphite after heating / Volume of heat-expandable graphite raw material before heating

Preferred forms of the above-mentioned heat-expandable sheet-shaped or putty-shaped refractory product include the following configurations.
[5] The thermal expandability according to the above [4], wherein the modified expandable graphite particles have a maximum length in the range of 100 to 1000 μm and a maximum thickness in the range of 5 to 150 μm. Sheet-shaped or putty-shaped refractory products.
[6] The heat-expandable sheet-like or putty-like refractory product according to the above [4] or [5], wherein the resin component is any resin selected from a thermoplastic resin and a thermosetting resin.

The present invention also provides a method for producing the following resin composition.
[7] The heat-expandable graphite raw material was modified in the modification step, and the obtained modified expandable graphite and the resin component were mixed and modified based on 100 parts by mass of the resin component. A method for producing a resin composition for obtaining a resin composition containing 5 to 300 parts by mass of expandable graphite.
In the modification step, the heat-expandable graphite raw material is heat-treated at a temperature of 100 ° C. to 250 ° C., and the bulk volume ratio obtained by the following formula after the heat treatment is 1.05 to 3. In the volume increasing step of increasing the volume of the heat-expandable graphite raw material so as to be 0 times, and the heat-treated heat-expandable graphite in a state where the bulk volume is increased in the volume increasing step, at room temperature. A method for producing a resin composition, which comprises a step of applying polyisosianate, which comprises adding polyisosianate and then heating to a temperature of 130 ° C. or lower.
Volume magnification = Volume of heat-expandable graphite after heating / Volume of heat-expandable graphite raw material before heating

Preferred forms of the above-mentioned method for producing the resin composition include those having the following configurations.
[8] The resin composition according to the above [7], wherein in the step of applying the polyisocyanate, the polyisocyanate is added in the range of 1 to 10 parts by mass to 100 parts by mass of the heat-treated expansive graphite. Manufacturing method.
[9] The above-mentioned [7] or [8], wherein the heat-treated expandable graphite particles have a maximum length in the range of 100 to 1000 μm and a maximum thickness in the range of 5 to 150 μm. Method for producing a resin composition of.

According to the present invention, the heat-expandable graphite is modified by applying a simple pretreatment without increasing the content ratio of the expandable graphite in the resin composition or increasing the particle size of the expandable graphite. By using a resin composition containing modified expansive graphite to form various products expected to prevent the spread of fire in the event of a fire, it is possible to achieve improvement in the expansion characteristics of the above products. Can be done. By using the expandable graphite provided by the heat-expandable graphite modification technique provided by the present invention, the content ratio of the heat-expandable graphite in the resin composition is increased, or the particle size of the heat-expandable graphite is increased. There is no problem that the mixing operation at the time of blending with the resin component becomes difficult and it takes a long time to make the mixture uniform. Further, by using the expandable graphite provided by the heat-expandable graphite modification technique provided by the present invention, heat is generated at the time of mixing with the resin component, which is generated when the heat-expandable graphite having a large particle size is used. The viscous resistance of the resin composition of the expansive graphite does not cause the particles to split into small pieces, which may prevent the desired performance from being exhibited, which does not cause a serious problem related to the basic performance. Further, since the heat-expandable graphite is a very expensive material, increasing the content ratio of the expandable graphite in the resin composition is disadvantageous in terms of raw material cost, whereas according to the technique of the present invention. It becomes possible to provide a resin composition having excellent economic efficiency and various products formed by using the resin composition, and it is possible to solve the problem of economic efficiency, which is a big problem in practical use.

It is a graph which shows the mass decrease every 30 minutes when each of the three kinds of commercially available products of thermal expansion graphite was heated at 200 ° C. It is a graph which shows the change of the bulk volume magnification at the time of heating in the temperature range of 190-255 ° C. about the commercial product of 3 kinds of heat-expandable graphite.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments. The present inventors have conventionally made a refractory product formed by using a resin composition containing modified heat-expandable graphite and a resin component, which can be expected to have a better fire spread prevention effect in the event of a fire. The present invention has been reached as a result of diligent studies to provide a novel technique for modifying heat-expandable graphite, which is simple, economical, and highly practical.

First, as a means for increasing the expansion coefficient, that is, the expansion characteristics of a product made of a resin composition containing expandable graphite during combustion due to a fire or the like, increasing the content ratio of thermally expandable graphite in the resin composition is a method. It is common. Further, it is known that when the particle size of the heat-expandable graphite contained in the resin composition (hereinafter referred to as the particle size) is large, the expansion coefficient is increased.

However, according to the study by the present inventors, when the content ratio of the heat-expandable graphite in the resin composition is increased or when the particle size of the heat-expandable graphite is increased, the mixing operation at the time of blending is performed. There is a problem that it becomes difficult and it takes a long time to make it uniform. Further, when heat-expandable graphite having a large particle size is used, when the heat-expandable graphite is mixed with the resin component to form a resin composition, the particles of the heat-expandable graphite are torn into fine particles due to the viscous resistance of the resin composition, which is the target. There is a concern that a fatal problem may occur in which the performance may not be exhibited.

In response to the above-mentioned various problems, the present inventors have found a novel method capable of improving the expansion characteristics of a product by subjecting a heat-expandable graphite raw material to a simple pretreatment. Specifically, the present inventors have found that "by heat-treating the heat-expandable graphite raw material in advance, the bulk volume ratio is 1.05 to 3.0 times that of the bulk volume of the raw material before heating. The modified expandable graphite specified in the present invention, which is defined as "a state in which polyisosianate is added to the heat-expandable graphite in a state where the volume of heat-treated bulk is increased". By using it, various problems in the prior art can be solved at once. That is, by using the modified expandable graphite specified in the present invention, it is possible to easily provide a product having more excellent expansion characteristics at a reasonable cost by using a normal resin composition production operation. Become. The modified expansive graphite that characterizes the present invention will be described in detail below. In the present invention, by heating the heat-expandable graphite raw material constituting the present invention, the bulk volume ratio of the heated heat-expandable graphite is 1.05 to 3.0 times, which is slightly larger than that of the raw material. The thermally expandable graphite in the increased state is called "expanded graphite". Further, the heat-treated "expanded graphite" to which polyisocyanate is added is called "modified expansive graphite".

The modified expandable graphite that characterizes the present invention and can realize a remarkable effect can be easily obtained from the heat-expandable graphite raw material by the following simple modification step. That is, in the modification step of the heat-expandable graphite raw material that characterizes the present invention, first, in the volume increasing step, the heat-expandable graphite raw material is heat-treated at a temperature of 100 ° C. to 250 ° C., as compared with that before the heat treatment. After the heat treatment, the volume of the heat-expandable graphite raw material is increased so that the coefficient of thermal expansion obtained by the following formula becomes 1.05 to 3.0 times to obtain "expanded graphite". Although it depends on the heat-expandable graphite raw material used, for example, by heat-treating the heat-expandable graphite raw material at a temperature of about 190 ° C. to 230 ° C., the bulk volume ratio is 1.05 to 3.0 times. "Graphite" can be obtained.
Volume magnification = Volume of heat-expandable graphite after heating / Volume of heat-expandable graphite raw material before heating

Next, in the step of applying the polyisocyanate, in the step of increasing the volume, the heat-treated heat-expandable graphite in a state where the bulk volume is increased to 1.05 to 3.0 times is "expanded graphite". , Polyisocyanate is added at room temperature. Then, after that, it can be obtained by an extremely simple operation of heating to a temperature of 130 ° C. or lower. The heating temperature at this time may be, for example, about 80 ° C. to 100 ° C.

Next, the background of finding the modified expansive graphite which is extremely useful as a constituent material of the resin composition specified in the present invention will be described. According to the study by the present inventors, when the heat-expandable graphite raw material is heated to a relatively low temperature of about 100 to 250 ° C., the layers of graphite are slightly expanded, and the volume of individual graphite particles is increased at a low magnification. The present inventors wondered if the object of the present invention could be achieved by conducting a more detailed study on this point. For that purpose, it is necessary to know how much the heat-expandable graphite raw material has expanded by heating at a relatively low temperature.

As a method for measuring a slight increase in volume that occurs in heat-expandable graphite particles when heated at a relatively low temperature, theoretically, the spread between layers of individual graphite particles is measured and calculated. It is conceivable to find the average value. However, this measurement method is not realistic and extremely difficult. Further, the problem of the present invention is not the microscopic phenomenon that appears in such individual graphite particles, but the macro that occurs when the heat-expandable graphite raw material constituting the resin composition is heated to a relatively low temperature. Behavior. Therefore, as an extremely easy and objective measurement method that meets the object of the present invention, the bulk volume magnification is used in the present invention. The bulk volume ratio is the ratio of the bulk volume of the sample collected from the heat-expandable graphite raw material before heating to the bulk volume of the sample sample expanded after heating, which is calculated by the following formula. Each bulk volume can be easily measured using a graduated cylinder.
Volume magnification = Volume of heat-expandable graphite after heating / Volume of heat-expandable graphite raw material before heating

The factor of the low magnification volume increase of the heat-expandable graphite caused by heating at a relatively low temperature, which is about 1.05 to 3.0 times the value obtained by the bulk volume magnification, is the factor of the volume increase of the heat-expandable graphite during the production of the heat-expandable graphite. It is presumed that the acid, oxide, water, etc. adhering to the surface of the graphite particles are dispersed by heating at a relatively low temperature. FIG. 1 shows the weight reduction curves of three types of commercially available heat-expandable graphite when each of them is heated at 200 ° C. and graphite is sampled every 30 minutes. As shown in FIG. 1, any of the heat-expandable graphites showed a weight loss of 1 to 2% in the initial 30-minute range, but did not progress in the subsequent 180-minute heating. It is judged to be different from the gasification of intercalated acid.

The graph of FIG. 2 shows the change in the bulk volume ratio when heated in the temperature range of 190 to 255 ° C. for the three types of commercially available products of the same type of heat-expandable graphite as in FIG. The bulk volume magnification on the vertical axis of the graph of FIG. 2 is measured by heating at the measurement points of each temperature display shown on the horizontal axis of the graph of FIG. 2 under the condition of holding for 30 minutes, and measuring the bulk volume at each measurement point. Then, it is a value obtained by (the volume of the heat-expandable graphite after heating / the volume of the heat-expandable graphite raw material before heating (room temperature)). As shown in FIG. 2, all of the commercially available products had a relatively gentle increase curve of bulk volume magnification in this temperature range. Heat-treated thermal expansion in a state where the bulk volume ratio is 1.05 to 3.0 times and the bulk volume is slightly increased for mixing with the resin component constituting the resin composition of the present invention. The graphite is in the temperature range of 100 ° C. to 250 ° C., for example, in the case of the commercially available heat-expandable graphite raw material illustrated, the heat-expandable graphite raw material is prepared at a temperature of about 190 ° C. to 230 ° C. from the graph of FIG. It can be easily obtained by heat treatment.

The technical feature of the resin composition of the present invention is that the heat-expandable graphite for mixing with the resin component constituting the resin composition has been heat-treated and has a bulk volume ratio of 1.05 to 3.0 times. It is a heat-expandable graphite (“expanded graphite”) with a certain volume slightly increased, and the heat-treated “expanded graphite” with this volume slightly increased is provided with polyisosianate. There is. As described above, assuming that the volume of the heat-expandable graphite is slightly increased by heating, the layers of the graphite particles are expanded by this operation. In the present invention, liquid polyisocyanate is added to "expanded graphite" in a state where the volume is slightly increased, and modified expansive graphite having such a constitution (modified expansive graphite) is provided. It is characterized in that it is a constituent component of a resin composition. According to the study by the present inventors, the bulk volume magnification of "expanded graphite" is 1.05 to 3.0 times, and although it depends on the heat-expandable graphite raw material, for example, it is about 1.1 to 2.0 times. A good effect can be obtained by using the "expanded graphite" of.

With the above configuration, the added polyisocyanate is in a state of being attached to the widened cracks of the "expanded graphite" particles. Here, the ratio of the amount of polyisosianate added to and applied to the "expanded graphite", more specifically, the amount of wet adhesion to the surface of the graphite particles and the amount of impregnation into the layers of the graphite particles is unknown. The modified expansive graphite (modified expansive graphite) obtained by the above-mentioned method in which polyisosianate is added to the slightly increased volume "expanded graphite" is used in the resin composition of the present invention. It was confirmed that the molded product obtained by using the resin composition exhibited extremely high expansion performance when blended as the expandable graphite constituting the above, which led to the present invention. According to the study by the present inventors, the amount of each component used as the whole resin composition is the same as that of the resin composition of the present invention, and the heat-expandable graphite raw material in the unheated state is made of poly. In the case of a comparative resin composition in which isocyanate is added, or after polyisocyanate is added to a resin component and uniformly dispersed, the heated "expanded graphite" used in the present invention is added to this resin component. In the case of the comparative resin composition having a structure in which "" was added and uniformly mixed, no particularly excellent expansion characteristics were exhibited in any of the cases. From these facts, the effectiveness of the resin composition of the present invention for a novel composition was confirmed. This point will be described later.

The expandable graphite raw material used in the resin composition of the present invention may be any commercially available commercially available product, and is not particularly limited. That is, it suffices that natural graphite, pyrolysis graphite, cache graphite, or the like is used as a raw material, and the acid component is intercalated between the layers of graphite by using an acid and an oxidizing agent, and the graphite is washed and purified. From the viewpoint of handling, it is desirable that the graphite particles have a particle size in the range of 20 to 1000 μm. There is no particular limitation on the thickness of the graphite particles, but from the viewpoint of handling, those in the range of 5 to 150 μm are desirable. The thickness of the graphite particles of the expandable graphite referred to in the present specification refers to the average distance from the bottom surface to the top surface of the layered graphite particles. The thickness is measured by photographing a vertical plane parallel to the maximum length (major axis) of graphite particles with an electron microscope, calculating the plane projection area, and dividing the area obtained by the parallel distance of the plane projection. Was taken as the thickness. The particle size of the graphite particles of expandable graphite is also referred to as the maximum length (major axis), and refers to the maximum distance between the upper surface or the bottom surface of the layered graphite particles in the direction perpendicular to the thickness direction. The thickness and particle size of graphite particles can be easily measured with a general high-performance optical microscope or electron microscope.

To obtain heat-treated heat-expandable graphite (“expanded graphite”) in which the bulk volume ratio, which characterizes the present invention, is increased by 1.05 to 3.0 times as compared with the bulk volume of the raw material before heating. The specific method of As a method for easily and stably obtaining low-magnification graphite in which the bulk volume ratio increases 1.05 to 3.0 times as much as the bulk volume of the raw material before heating at a relatively low heating temperature, for example. , The heat-expandable graphite raw material is put in an appropriate container, put in a hot air furnace, an electric furnace, or the like, and heated from the surroundings. By heating the heat-expandable graphite raw material at a relatively low temperature of about 100 ° C. to 250 ° C., for example, at a temperature of about 190 ° C. to 230 ° C., "expanded graphite" having a desired magnification can be obtained. Moreover, as can be seen from FIG. 2 described above, since the increase in volume is an extremely gentle increase curve and is extremely easy to control, the "expanded graphite" used in the present invention can be easily obtained. Referenced FIGS. 1 and 2 are curves under the set heating conditions, and the heating conditions differ depending on the method of implementation, so that the heating time is not specified. That is, by heating the heat-expandable graphite raw material, the coefficient of thermal expansion of the heated heat-expandable graphite may be 1.05 to 3.0 times, and in particular, the heating method, heating conditions, and other conditions. I don't care.

The resin composition of the present invention is modified as expandable graphite to be mixed with a resin component in a state where polyisocyanate is added to "expanded graphite" having a bulk volume ratio of 1.05 to 3.0 times. It is characterized by using expansive graphite. Specific methods for applying polyisocyanate to "expanded graphite" are as follows. Polyisocyanate is added to "expanded graphite" obtained by heating a heat-expandable graphite raw material in advance at room temperature, and then heated at a temperature of 130 ° C. or lower. As a result, "modified expandable graphite" is obtained in a state in which polyisocyanate is impregnated between the layers of graphite particles opened as the bulk volume ratio increases, or in a state in which the graphite particles are wet and adhered to the surface. In the resin composition of the present invention, "modified expandable graphite" in this state is used as an essential constituent component to be contained in the resin component.

The present inventors have prepared a resin composition containing "modified expansive graphite" obtained by the above-mentioned treatment operation, and the volume of the expanded body remaining after combustion at a high temperature in the product obtained by using the resin composition. Is increased, that is, the expansion characteristic is increased. According to the study by the present inventors, the amount of polyisocyanate added to "expanded graphite" is preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of expanded graphite on a mass basis. If it is 1 part by mass or less, the effect is small, and if it exceeds 10 parts by mass, it is difficult to obtain a uniform composition of the resin composition when "modified expandable graphite" is mixed with the resin component.

Further, according to the study by the present inventors, when the bulk volume ratio of "expanded graphite" to which polyisocyanate is added is less than 1.05 times, the effect of adding polyisocyanate is small, while 3. When it exceeds 0 times, the "expanded graphite" becomes brittle, and when mixed with the resin component, it is finely crushed and the effect is reduced. The bulk volume magnification of the "expanded graphite" constituting the present invention is preferably in the range of 1.1 to 2.0 times, particularly 1.1 to 1.6 times.

The polyisocyanate used in the present invention refers to a compound having two or more isocyanate groups in the molecule. There are no particular restrictions on the structure or molecular weight of the polyisocyanate, but since it is intended to impregnate or wet and adhere well between the layers of expanded graphite particles, it has a relatively small molecular weight, that is, a low viscosity. Is preferable. For example, 4,4'diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate and the like can be mentioned. Further, a multimer of these diisocyanates may be used, for example, Crude M. D. Examples of I include MS-20 (trade name, manufactured by BASF IONAC Polyurethane), coronate HX (trade name, manufactured by Tosoh Corporation), which is a multimer of aliphatic isocyanate.

When polyisocyanate having a particularly high viscosity is used, a small amount of low boiling point solvent can be added to reduce the viscosity. However, in general, polyisocyanate has strong activity, so it is desirable that polyisocyanate has low volatility from the viewpoint of work. In addition, when a solvent is added, there is a concern that the solvent may remain, so it is desirable not to use it if possible. From these points, Crude M. D. I and M. D. I and Coronate HX are the most desirable.

In contrast to the effect of improving the expansion characteristics achieved by the present invention, in the "modified expansive graphite" that characterizes the present invention, some polyisocyanate is impregnated or wet-adhered between the layers of the "expanded graphite". It has not been confirmed whether or not the reaction has occurred. However, as will be described later, from the comparison between Examples and Comparative Examples, the resin composition of the present invention having a structure in which the "modified expansive graphite" subjected to this operation in advance is compared with the resin compositions having other structures. It was confirmed that it clearly exhibited excellent expansion characteristics.

That is, first, polyisocyanate is added in advance to unheated heat-expandable graphite as a raw material, not in a state where the layers of graphite particles are opened at a low magnification, which constitutes the present invention. The molded product obtained by using the resin composition prepared by using the heat-expandable graphite has the expansion characteristics of the expanded product (residue) after combustion in the "expanded graphite" of the present invention with open layers and polyisosia. It was confirmed that it was inferior to the expansion characteristics obtained in the case of the molded product obtained by using "modified expandable graphite" in which nat was added in advance. Further, even if "expanded graphite" is used, polyisocyanate is simply added uniformly to the resin composition without adding polyisocyanate to "expanded graphite" to obtain "modified expansive graphite". However, it was confirmed that the effect of improving the expansion characteristics, which is the object of the present invention, cannot be obtained.

In evaluating the effects of the resin compositions of Examples and Comparative Examples, as the expandable graphite, the heat-expandable graphite as a raw material and the "expanded graphite" in which the layers of the graphite particles expanded at a low magnification are opened. , And "modified expansive graphite" obtained by imparting polyisosianate to the "expanded graphite" was appropriately used. "Modified expandable graphite" is obtained by adding a predetermined polyisocyanate to "expanded graphite" at room temperature and then heating at 130 ° C. for 20 minutes to allow the polyisocyanate to blend into the heat-expandable graphite. Was used. A resin composition was prepared by mixing these expandable graphites with a resin component.

In addition, various conditions such as preparation of a test piece sheet sample for confirming expansion characteristics during combustion from the resin composition used when evaluating the effects of the resin compositions of Examples and Comparative Examples are described in Examples. Described in the comparative example. Then, the expansion characteristics intended by the present invention were measured as follows and used for evaluation. Each sheet-shaped sample is placed in a combustion container, burned in an electric furnace at 600 ° C. for 30 minutes, cooled to room temperature, and the height of the inflatable body taken out of the container is measured, thereby calculating the volume. Then, the obtained calculated value was divided by the weight (mass) of the test sample before heating, and the value was expressed as the expansion characteristic. Using this value, the expansion characteristics were relatively evaluated.

The combustion container used above has a rectangular shape with a base of 21 mm × 46 mm, a height of 50 mm, an open upper part, and a closed bottom and all sides. A sheet-shaped test piece was cut out and set on the bottom of this container so as to have a size of 20 to 21 mm × 45 to 46 mm and a weight (mass) of 1.48 g. Here, since the specific gravity of the test sample is exactly different and the thickness of the sheet is also slightly different and different, the expansion characteristics are determined by the sheet thickness of the test sample and the height of the inflator after combustion. Expressed as a ratio, it becomes complicated by adding some factors to the judgment of the effect. Therefore, in the present invention, the test sample is prepared in the form of a sheet having substantially the same thickness as described above, but the final adjustment was obtained after combustion using a sample having the same weight (mass). The value obtained by dividing the volume of the expander by the weight (mass) of the sample was defined as the expansion characteristic for comparative evaluation.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. The term "part" is based on mass unless otherwise specified.

[Preparation of "expanded graphite"]
As the heat-expandable graphite raw material, commercially available products of the following brands were used. Hereinafter, the product name will be described.
-SYZR802 (trade name): manufactured by Sanyo Trading Co., Ltd., 1000 ° C expansion degree 230 ml / g
-SYZR502 (trade name): manufactured by Sanyo Trading Co., Ltd., 1000 ° C expansion degree 250 ml / g
EG-E300 (trade name) Alias (Expanded graphite): Made by Qingdao Yanhai carbon materia Is, 1000 ° C expansion degree 270 ml / g

In the embodiment, the heat-expandable graphite raw material is heated in a temperature range of 100 ° C. to 250 ° C., the bulk volume increases, and the bulk volume magnification (bulk volume magnification) becomes the values shown in Table 1, respectively. Further, the slightly expanded heat-treated graphite was subjected to a test as "expanded graphite". The bulk volume ratio is a calculated value obtained by "the bulk volume of the heat-expandable graphite after heating / the bulk volume of the heat-expandable graphite raw material before heating" using the bulk volume of each measured sample. The volume of bulk used in this formula was measured by using a measuring cylinder with a heat-expandable graphite raw material before heating and a heat-treated "expanded graphite" sample in which the raw material was heated in the above temperature range and the volume was slightly increased. Each was put in and tapped lightly twice to measure the volume of each.

[Examples 1-1 to 1-4, Comparative Example 1] (Resin component: polyvinyl chloride resin)
The following components are used in the amounts shown in Table 2 as components other than "expanded graphite", which is the heat-treated heat-expandable graphite prepared by the method described above, which was used when preparing the resin composition. There was. As shown in Table 2, in this example, a polyvinyl chloride resin was used as the resin component. As the polyvinyl chloride resin abbreviated as PVC in Table 2, Luron paste 772A (trade name, manufactured by Tosoh Corporation, hereinafter abbreviated as PVC) was used. The polyisocyanate to be applied to the previously prepared "expanded graphite" includes Crude M. D. I (hereinafter abbreviated as MS-20) was used. In this example, the following additives were used as other additives. Dioctyl phthalate (hereinafter abbreviated as DOP) was used as a plasticizer, ammonium polyphosphate (abbreviated as APP) was used as a flame retardant, and calcium carbonate was also used. For DOP, APP and calcium carbonate, the reagents were used as they were.

In this example, SYZR502 having a bulk volume magnification of 1.42 was used as the "expanded graphite". Then, as described below, "modified expansive graphite" to which polyisocyanate was added was obtained, and these were used in Examples 1-1 to 1-4. That is, MS-20 is added to and mixed with 100 parts of "expanded graphite" at room temperature so that 1 part to 4 parts are blended as shown in Table 2, and then heated at 130 ° C. for 20 minutes. By doing so, polyisocyanate was attached to and impregnated with "expanded graphite" to impart MS-20. On the other hand, in Comparative Example 1, "expanded graphite" was used as it was. Using the above-mentioned "modified expandable graphite" or "expanded graphite", respectively, and mixing them with other resin components and additive components in the formulation shown in Table 2, Examples 1-1 to Example 1 -4, The resin composition of Comparative Example 1 was prepared.

[Evaluation method of resin composition]
<Preparation of sample for combustion test>
First, each resin composition prepared as described above is well stirred to obtain a uniform fluid. Each of these fluids was used, coated on a release plate to a predetermined thickness, and then solidified into a sheet by heating at 160 ° C. for 10 minutes. The thickness was set to about 1.0 to 2.0 mm. The obtained sheet-shaped molded product was used as a sample to be used for a combustion test for each resin composition of Examples and Comparative Examples.

Specifically, the sheet-shaped samples used for the combustion test obtained as described above are cut so that the weights are constant to obtain test samples, and the obtained samples are used for the combustion test. The expansion characteristics of the resin compositions of Examples and Comparative Examples were evaluated. In the above, when cutting the sheet-shaped sample used for the combustion test so that the weight becomes constant, the sample is placed in the range of about 20 to 21 mm × 45 to 46 mm so as to fit in the container used for the combustion test. It was cut into a rectangular shape and adjusted so that the weight (mass) of the sample for the combustion test was constant at 1.48 g.

<Combustion test>
Using the combustion test sample obtained as described above, the combustion test was performed as follows. First, a sample for a combustion test was placed on the bottom of a rectangular iron container having a base of 21 mm × 46 mm and a height of 50 mm, which was open at the top and closed at the bottom and all sides. Next, an iron container on which a sample for a combustion test was placed was placed in an electric furnace at 600 ° C. for 30 minutes to burn the sample, and an expanded body was obtained as a residue after combustion. After cooling to room temperature, the volume of the expander is measured, and the weight of the sample for the combustion test before heating and the expansion characteristics, which are the values (ml / g) divided by 1.48 g, are shown in Table 2. Indicated. In addition, the obtained numerical values were relatively compared and used as a reference for determining the superiority or inferiority of the expansion characteristics of the resin compositions of Examples and Comparative Examples. In Example 1, the effect on the expansion characteristics caused by treating "expanded graphite" with MS-20 of polyisocyanate and modifying it was confirmed. Table 2 shows the ratio (improvement rate) of the expansion characteristics calculated using the numerical values of the expansion characteristics of Examples 1-1 to 1-4 using the numerical values of the expansion characteristics of Comparative Example 1 as reference values. As a result, as shown in Table 2, it was confirmed that the effect of improving the expansion characteristics was clearly obtained by modifying the "expanded graphite" with MS-20.

[Comparative Example 2] (Example using unheated heat-expandable graphite)
In Comparative Example 2-1 the same heat-expandable graphite raw material SYZR502 used in Example 1 and Comparative Example 1 was used without heat treatment and without heating. Then, in Comparative Examples 2-2-2-4, the same polyisocyanate MS-20 as used in Example 1 was added to the non-heat-treated heat-expandable graphite raw material in the amount shown in Table 3 at room temperature. And mixed. Then, it was heated at 130 ° C. for 20 minutes in the same manner as in Example 1. Other operations are the same as in Example 1, each resin composition is prepared, each resin composition is used to obtain a sheet-shaped molded product sample for a combustion test, and the obtained sample is cut. A sample for a combustion test was prepared, and further, each of the obtained samples was subjected to a combustion test.

The same evaluation method for the resin composition as in Example 1 was carried out, and the values of the expansion characteristics obtained in the combustion test were calculated and shown in Table 3. Then, using the calculated value indicating the obtained expansion characteristics, first, as in Example 1, the effect of applying MS-20 to the “expanded graphite” on the expansion characteristics was examined by the expansion of Comparative Example 2-1. Using the numerical value of the characteristic as the reference value, calculate the ratio of the expansion characteristic using the numerical value of the expansion characteristic of Comparative Examples 2-2-2-4, and use it as "Evaluation 1 (improvement rate) of the expansion characteristic" in Table 3. Indicated. As a result, as shown in Table 3, it was found that even if polyisocyanate was added to the unheated heat-expandable graphite raw material which was not heat-treated, the effect of improving the expansion characteristics could not be obtained.

Further, when "modified expansive graphite" modified by adding MS-20 of polyisocyanate to the heat-treated "expanded graphite" in Example 1 is used, the expansion characteristics shown in Table 2 are exhibited. Using the value and the value of the expansion characteristic shown in Table 3 in the case of Comparative Example 2 in which the same amount of polyisocyanate was added using the heat-expandable graphite raw material which was not heat-treated and remained unheated, was used. In order to compare the effect of improving the expansion characteristics, the ratio of "values of expansion characteristics in Table 3 / values of expansion characteristics in Table 2" calculated for each of the examples in which the same amount of MS-20 was blended was calculated as "evaluation of expansion characteristics". 2 ”is shown in Table 3. As a result, as shown in "Evaluation 2 of expansion characteristics" in Table 3, "expanded graphite" obtained by heat-treating a heat-expandable graphite raw material was used as the expandable graphite constituting the resin composition. For the first time, it was confirmed that the effect of improving the expansion characteristics can be obtained by adding graphite cyanate.

[Comparative Example 3]
In this comparative example, the expandable graphite blended in the resin composition has a bulk volume ratio similar to that of Example 1 as "expanded graphite" which is heat-treated heat-expandable graphite in a state where the volume is slightly increased. 1.42 SYZR502 was used. Moreover, MS-20 was used as a polyisocyanate. However, unlike the case of Example 1, MS-20 is adhered and impregnated to "expanded graphite", and "modified expandable graphite" to which polyisocyanate is added is blended with the resin component. Instead, in this comparative example, MS-20 was simply added to the resin composition, blended, and used in combination with "expanded graphite". Specifically, the formulations other than MS-20 in the components shown in Table 4 were first mixed well, and then MS-20 was added in that state to make them uniform to obtain the resin composition of this comparative example. That is, in the resin composition of this comparative example, SYZR502 of "expanded graphite" and polyisocyanate of MS-20 are simply coexisted in the resin composition like other additives.

For other operations, the resin compositions having the formulations shown in Table 4 were prepared in the same manner as in Example 1, and each resin composition was used to obtain a sheet-shaped molded product sample for a combustion test. The obtained sample was cut to prepare a sample for a combustion test, and further, using the obtained sample, a combustion test was carried out in the same manner as in Example 1. Further, the values of the expansion characteristics obtained in the combustion test were calculated by the same method as in the case of Example 1, and are shown in Table 4. Further, Table 2 shows the case where the "modified expandable graphite" having the structure of the heat-treated "expanded graphite" modified by adding MS-20 of polyisocyanate to the heat-treated "expanded graphite" was used. For the purpose of comparing the improvement effect by using the value of the expansion characteristic and the value of the expansion characteristic in the case of Comparative Example 3 of the configuration in which polyisocyanate is simply blended and coexisted with "expanded graphite", MS- The ratios for which "values of expansion characteristics in Table 4 / values of expansion characteristics in Table 2" were calculated for each of the examples in which the same amount of 20 was blended are shown in Table 4 as "evaluation 3 of expansion characteristics". As shown in the result of "Evaluation 3 of expansion characteristics" in Table 4, the heat-expandable graphite raw material is heat-treated to obtain "expansion graphite", and polyisosianate is further added to this "expansion graphite". It was confirmed that a higher effect of improving the expansion characteristics can be obtained for the first time by adopting the configuration of Example 1 in which the expansion graphite having a configuration in which the “expanded graphite” is modified with MS-20 is used in the resin composition. It was.

[Summary of evaluation results regarding the effect of improving expansion characteristics]
As shown in Tables 2 to 4, the expansion characteristics in the combustion test realized by the resin composition of Example 1 in Table 2 are the "expanded graphite" specified in the present invention shown in Tables 3 and 4. Is clearly different from the expansion characteristics in the combustion test conducted using the resin compositions of Comparative Examples 2 and 3 without using "modified expansive graphite" modified with polyisocyanate. It was confirmed that an improvement effect could be obtained. That is, by adding polyisocyanate to SYZR502, which is "expanded graphite" whose bulk volume is slightly increased by heat treatment, and modifying it, and using "modified expandable graphite" as a constituent component of the resin composition. , Expansion characteristics can be improved. On the other hand, in the case of the resin composition of Comparative Example 2 in which polyisosianate is added to a non-heated heat-expandable graphite raw material that is not heat-treated, or in the case of heat treatment, the bulk volume is slightly increased. Although "expanded graphite" is used, it is not used by further modifying "expanded graphite" with polyisosianate, but simply by blending polyisosianate in the resin composition. In the case of the resin composition of Comparative Example 3, it was confirmed that the expansion characteristics were not effectively improved.

[Example 2, Comparative Example 4]
The operations other than using 4,4'diffelmethane diisocyanate (abbreviated as MDI) as the polyisocyanate and SYZR802 as the heat-expandable graphite raw material were carried out in the same manner as in Example 1. The resin composition of Example 2 was prepared. In addition, polyisocyanate was added to M. D. Comparative Examples 4-1 and 4-2 were the same as those of Comparative Example 2 in which the heat-expandable graphite raw material which was not heat-treated was used as it was instead of I. In addition, polyisocyanate was added to M. D. Instead of I, heat-treated "expanded graphite" was used, and M.I. D. Examples of I being simply blended and used in combination were designated as Comparative Examples 4-3 and 4-4. Combustion tests were carried out in the same manner as in Example 1, and the expansion characteristics were calculated in the same manner. Table 5 shows the composition of the resin composition and the expansion characteristics obtained by the combustion test.

Then, with respect to the value of the expansion characteristic obtained in Example 2, the ratio was calculated based on the value of each expansion characteristic obtained in the above Comparative Example 4 obtained in the same blending amount, and the effect of improving the expansion characteristic was confirmed. .. As shown in Table 5, "expanded graphite", which was subjected to the same treatment as in Example 1 and whose volume was slightly increased by heating, was obtained from the polyisocyanate M.I. D. It was also confirmed that in the case of Example 2 in which the resin composition was prepared by using "modified expandable graphite" modified using I, the expansion characteristics were clearly improved as compared with Comparative Example 4. ..

[Example 3, Comparative Examples 5 to 7] (Resin component: unsaturated polyester resin)
In the formulation shown in Table 6, the same operation as in Example 1 was performed except that an unsaturated polyester resin was used instead of PVC as the resin component of the resin composition, and SYZ802 was used as the heat-expandable graphite raw material. The resin composition of Example 3 was prepared. Further, in the formulation shown in Table 6, an unsaturated polyester resin was used as the resin component of the resin composition, and the operation was carried out in the same manner as in Comparative Example 1 except that the heat-expandable graphite raw material was replaced with SYZ802. Resin composition of. In addition, in the formulation shown in Table 6, unsaturated polyester resin was used instead of PVC as the resin component of the resin composition, and the heat-expandable graphite raw material used without heat treatment was replaced with SYZ802. The resin compositions of Comparative Examples 6 and 7 were prepared in the same manner as in Comparative Example 2. As the unsaturated polyester resin, a polyester for hand-loading manufactured by Nippon Tokushu Paint Co., Ltd. was mixed at a ratio of 99 main agent / 1 curing agent. SYZ802 was used as the heat-expandable graphite raw material, and in Comparative Examples 6 and 7, the unheated raw material was used as it was without heat treatment. In Example 3 and Comparative Example 5, the bulk volume was as described above. "Expanded graphite" expanded to a magnification of 1.50 was used.

Combustion tests were carried out using each of the resin compositions having the formulations shown in Table 6 prepared as described above. In this example, unlike the case of Example 1 in which PVC is used as the resin component, when preparing a sample for a combustion test, the release plate is coated with a predetermined thickness and then heated at 60 ° C. for 20 minutes to solidify. It was used as a sample. Subsequent operations and evaluation methods for the combustion test are the same as those performed in Example 1. In Table 6, the blending of the resin composition, the respective expansion characteristic values obtained in the combustion test, and the ratio of the expansion characteristic value of Example 3 to the expansion characteristic value of each comparative example were obtained, and the ratio thereof was obtained. The result of relative evaluation is shown.

As shown in Table 6, even when the resin component is changed to an unsaturated polyester resin, polyisocyanate is added to the "expanded graphite" as the expansive graphite constituting the resin composition as specified in the present invention. It was confirmed that the effect of improving the expansion characteristics was clearly obtained by using the modified "modified expandable graphite".

[Example 4, Comparative Examples 8 to 10] (Resin component: Acrylic resin)
In the formulation shown in Table 7, acrylic resin is used instead of PVC as the resin component of the resin composition, EG-E300 is used as the raw material for the heat-expandable graphite, and Coronate HX (trade name, Tosoh) is used as the polyisocyanate. The resin composition of Example 4 was prepared by operating in the same manner as in Example 1 except that the resin composition of Example 4 was used. Further, in the formulation shown in Table 7, the resin of Comparative Example 8 was obtained in the same manner as in Comparative Example 1 except that acrylic resin was used as the resin component of the resin composition and the heat-expandable graphite raw material was replaced with EG-E300. The composition was prepared. Further, in the formulation shown in Table 7, acrylic resin was used as the resin component of the resin composition, and the heat-expandable graphite raw material used without heat treatment was replaced with EG-E300, as compared with Comparative Example 2. The resin compositions of Comparative Examples 9 and 10 were prepared in the same manner. As the acrylic resin, MH101-5 (trade name) manufactured by Fujikura Kasei Co., Ltd. was used by dissolving it in ethyl acetate in a 30% solution. EG-E300 was used as the heat-expandable graphite raw material, and in Comparative Examples 9 and 10, the unheated raw material was used as it was without heat treatment. In Example 4 and Comparative Example 8, the bulk volume magnification was 1.47 times. "Expanded graphite" that was expanded to the above was used.

In Example 4, a sample for a combustion test was prepared as follows. First, the acrylic resin described above was dissolved in toluene at a concentration of 30%. Then, in this solution, coronate HX as a polyisocyanate was added to "expanded graphite" having a bulk volume of 1.47 times, which was obtained by heating the EG-E300 raw material, at room temperature in the amount shown in Table 7. After adding and mixing with each other and heating at 130 ° C. for 20 minutes, polyisocyanate was attached to and impregnated with "expanded graphite", and coronate HX was added to obtain "modified expansive graphite". .. Then, the obtained "modified expanded graphite" was well mixed with other formulations to obtain a resin composition. Using the obtained resin composition, the release plate was coated to a predetermined thickness in the same manner as in Example 1 to obtain a sheet-shaped molded product used for the combustion test. When the sheet-shaped molded product was obtained, it was left at 20 to 30 ° C. for 24 hours to evaporate and solidify the solvent. Other than that, a combustion test was carried out using a sheet-shaped sample in the same manner as in Example 1 to determine the expansion characteristics. The resin compositions of Comparative Examples 8 to 10 were also subjected to a combustion test according to the above to determine expansion characteristics.

Table 7 shows the composition of the resin composition and the expansion characteristics obtained by the combustion test. In Table 7, the blending of the resin composition, the respective expansion characteristic values obtained in the combustion test, and the ratio of the expansion characteristic value of Example 4 to the expansion characteristic value of each comparative example were obtained, and the ratio thereof was obtained. The result of relative evaluation is shown.

As shown in Table 7, even when the resin component is changed to acrylic resin, polyisocyanate is added to "expanded graphite" as the expansive graphite constituting the resin composition to modify it as specified in the present invention. It was confirmed that the effect of improving the expansion characteristics was clearly obtained by using the modified "modified expandable graphite". The acrylic resin in Table 7 is described as having a solid content of 100%.

Claims (9)

A resin composition containing modified expansive graphite and a resin component.
Based on 100 parts by mass of the resin component, the modified expandable graphite is contained in an amount of 5 to 300 parts by mass.
By heat-treating the heat-expandable graphite raw material in advance with the modified expandable graphite, the bulk volume ratio obtained by the following formula is 1.05 to 3.0 as compared with the bulk volume of the raw material before heating. A resin composition characterized by having polyisosianate added to heat-expandable graphite in a state where the volume has been doubled and the volume of heat-treated bulk has increased.
Volume magnification = Volume of heat-expandable graphite after heating / Volume of heat-expandable graphite raw material before heating The resin composition according to claim 1, wherein the modified expandable graphite particles have a maximum length in the range of 100 to 1000 μm and a maximum thickness in the range of 5 to 150 μm. The resin composition according to claim 1 or 2, wherein the resin component is any resin selected from a thermoplastic resin and a thermosetting resin. A heat-expandable sheet-like or putty-like refractory product, which is a molded product composed of a resin composition containing modified expandable graphite and a resin component.
Based on 100 parts by mass of the resin component, the modified expandable graphite is contained in an amount of 5 to 300 parts by mass.
By heat-treating the heat-expandable graphite raw material in advance with the modified expandable graphite, the bulk volume ratio obtained by the following formula is 1.05 to 3.0 as compared with the bulk volume of the raw material before heating. A heat-expandable sheet or putty characterized by having polyisosianate added to the heat-expandable graphite in a state where the volume of heat-treated bulk has increased by a factor of two. Fireproof product.
Volume magnification = Volume of heat-expandable graphite after heating / Volume of heat-expandable graphite raw material before heating The heat-expandable sheet or the form according to claim 4, wherein the modified expandable graphite particles have a maximum length in the range of 100 to 1000 μm and a maximum thickness in the range of 5 to 150 μm. Putty-like refractory product. The heat-expandable sheet-like or putty-like refractory product according to claim 4 or 5, wherein the resin component is any resin selected from a thermoplastic resin and a thermosetting resin. The heat-expandable graphite raw material is modified in the modification step, the obtained modified expandable graphite and the resin component are mixed, and the modified expandable graphite is based on 100 parts by mass of the resin component. A method for producing a resin composition, which comprises 5 to 300 parts by mass of
In the modification step, the heat-expandable graphite raw material is heat-treated at a temperature of 100 ° C. to 250 ° C., and the bulk volume ratio obtained by the following formula after the heat treatment is 1.05 to 3. In the volume increasing step of increasing the volume of the heat-expandable graphite raw material so as to be 0 times, and the heat-treated heat-expandable graphite in a state where the bulk volume is increased in the volume increasing step, at room temperature. A method for producing a resin composition, which comprises a step of adding polyisocyanate and then heating to a temperature of 130 ° C. or lower.
Volume magnification = Volume of heat-expandable graphite after heating / Volume of heat-expandable graphite raw material before heating The method for producing a resin composition according to claim 7, wherein in the step of applying the polyisocyanate, the polyisocyanate is added in the range of 1 to 10 parts by mass to 100 parts by mass of the heat-treated expansive graphite. The production of the resin composition according to claim 7 or 8, wherein the heat-treated expandable graphite particles have a maximum length in the range of 100 to 1000 μm and a maximum thickness in the range of 5 to 150 μm. Method.

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