JP5834231B2 - Flame retardant resin composition - Google Patents

Description

  The present invention relates to a flame retardant resin composition.

  Conventionally, a flame retardant containing a halogen atom such as bromine is sometimes blended in a resin composition using a thermoplastic resin such as a polyester resin or a polyolefin resin as a matrix resin for safety in a fire or the like. However, in recent years, a halogen-free flame-retardant resin composition has been demanded in order not to put a burden on the environment.

  Therefore, it has been studied to use a low-melting-point glass having a low endothermic peak temperature at the time of melting as a flame retardant blended in the resin composition. For example, Patent Document 1 discloses that an inorganic substance such as glass having an endothermic peak at the time of melting in the range of 401 to 700 ° C. is used as a flame retardant for the resin composition.

  When a molded body formed from a resin composition containing such a low-melting glass is exposed to a high temperature, the internal low-melting glass is melted and reaches the surface of the molded body to form a coating. This coating blocks the supply of oxygen from the outside to the inside of the molded body, and even if the resin component in the molded body is decomposed and gas is generated, the outflow of this gas to the outside is blocked by the coating. Thereby, a molded object exhibits a flame retardance.

  However, the flame retarding effect of only the low melting point glass may not be sufficient, and a large amount of low melting point glass may be required in order to sufficiently improve the flame retardancy of the molded article. This is thought to be because the low-melting-point glass that reached the surface of the molded body falls off from the molded body at a considerable rate. However, when a large amount of low-melting-point glass is blended in the resin composition, there is a problem that adverse effects such as a decrease in mechanical strength such as toughness of the molded article occur.

  It has also been attempted to further improve the flame retardancy of a molded article by blending a low melting glass and other flame retardant in the resin composition. For example, in Patent Document 2, 5 to 15% by weight of magnesium hydroxide having an average particle diameter of 1 to 5 μm and 0.5 to 5% by weight of non-lead low-melting glass are blended in the epoxy resin composition, and the magnesium hydroxide is further added. It is disclosed that 50 to 80% by weight of an inorganic filler containing is blended.

JP 2001-234168 A Japanese Patent Application Laid-Open No. 2002-241587

  However, even in the technique described in Patent Document 2, the ratio of the total amount of the low-melting glass and the inorganic filler in the resin composition is 100 with respect to 100 parts by mass of the resin in order to achieve sufficient flame retardancy. It becomes more than the mass part. For this reason, there existed a problem that characteristics, such as mechanical strength which resin originally has, will be impaired.

  The present invention has been made in view of the above-mentioned reasons, and its object is to form a molded article that contains a flame retardant containing a low-melting glass and exhibits both high flame retardancy and high mechanical properties. It is to provide a flame retardant resin composition that can be made.

The flame-retardant resin composition according to the present invention contains a matrix resin, a low-melting glass, and an inorganic filler other than the low-melting glass, and the ratio of the low-melting glass to 100 parts by mass of the matrix resin is 1 to 40. The ratio of the inorganic filler relative to 100 parts by mass of the matrix resin is in the range of 1 to 40 parts by mass, and the mass ratio of the former to the latter of the low-melting glass and the inorganic filler is 1: 4. The inorganic filler is magnesium hydroxide particles having an average particle diameter of 100 nm or less, the low-melting glass is particulate, and the average particle diameter is 0.5 μm to 10 μm. It is a range.

  In the present invention, the surface of the inorganic filler is preferably coated with a silane coupling agent.

  In the present invention, the inorganic filler is preferably at least one selected from magnesium oxide, aluminum oxide, magnesium hydroxide, and aluminum hydroxide.

  In the present invention, the matrix resin is preferably a thermoplastic resin.

  ADVANTAGE OF THE INVENTION According to this invention, the flame-retardant resin composition which contains the flame retardant containing low melting glass and can form the molded object which exhibits both high flame retardance and a high mechanical characteristic is obtained.

  The flame retardant resin composition according to the present embodiment contains an inorganic filler other than the matrix resin, the low melting glass, and the low melting glass. A molded body is formed by molding the flame retardant resin composition by an appropriate method according to the composition.

  The ratio of the low melting point glass to 100 parts by mass of the matrix resin in the flame retardant resin composition is in the range of 1 to 40 parts by mass, and the ratio of the inorganic filler to 100 parts by mass of the matrix resin is in the range of 1 to 40 parts by mass. It is. Further, the mass ratio of the former to the latter of the low melting point glass and the inorganic filler in the flame retardant resin composition is in the range of 1: 4 to 1: 1. Furthermore, the average particle size of the inorganic filler is 100 nm or less.

  Since the molded body formed from the flame retardant resin composition having such a composition has a low ratio of the total amount of the low melting point glass and the inorganic filler to the matrix resin in the flame retardant resin composition, the matrix resin The properties such as the high mechanical strength inherently possessed are sufficiently maintained. In addition, the low melting point glass and the inorganic fine particles act in a composite manner, so that the molded body has high flame retardancy. This is considered to be due to the fact that the flame retardant action due to the following complex factors works.

  When the molded body is heated, a phenomenon (necking phenomenon) occurs in which the low melting point glass in the molded body melts and reaches the surface of the molded body to form a film. By this coating, the supply of oxygen from the outside to the molded body is blocked, and the outflow of gas generated by the decomposition of the resin component constituting the molded body is blocked. Thereby, the temperature (exothermic peak temperature) at which combustion of the molded body continuously occurs increases, and the molded body exhibits flame retardancy.

  However, the outflow of gas to the outside is not sufficiently inhibited only by the film formed by the necking phenomenon. The gas generated by the decomposition of the resin component constituting the molded body is generated not only on the surface of the molded body but also inside thereof, and the gas becomes bubbles inside the molded body. In the case of small bubbles having a diameter of about 100 μm or less, the coating formed by the necking phenomenon sufficiently inhibits the movement of the bubbles. However, when larger bubbles reach the coating, cracks are likely to occur in the coating, and gas may flow out of the molded body through the crack.

  However, in this embodiment, not only the low melting point glass but also an inorganic filler having an average particle size of 100 nm or less is dispersed in the molded body, so that even if the resin component decomposes on the surface layer of the molded body, the surface layer is inorganic. A layer composed of the filler remains. The layer composed of the inorganic filler hinders the movement of large bubbles, so that the large bubbles are difficult to reach the coating, and thus the coating is difficult to crack. The effect that the layer composed of such an inorganic filler inhibits the movement of bubbles is exhibited by the particle size of the inorganic filler being 100 nm or less, or is considered to be greatly enhanced by this.

  In this way, the coating formed by the necking phenomenon inhibits the movement of small bubbles and the layer composed of the inorganic filler inhibits the movement of large bubbles, thereby significantly suppressing the outflow of gas from the molded body, Thereby, it is thought that the flame retardance of a molded object improves greatly.

  Furthermore, the particle size of the inorganic filler in the molded body is small, that is, the specific surface area of the inorganic filler is large, so that the drip phenomenon (a phenomenon in which the molten resin is dripped) is significantly suppressed when the molded body is heated. In addition, the formation of char (carbonized layer) in the molded body is promoted. This also greatly improves the flame retardancy of the molded body.

  The components in the flame retardant resin composition will be described in more detail.

  As the matrix resin, an appropriate resin can be used as long as it can be generally used as a matrix resin of a molding resin composition. From the viewpoint of suppressing the halogen content of the flame retardant resin composition, the matrix resin preferably contains no halogen.

  When the matrix resin is particularly a thermoplastic resin, the flame retardancy of the molded product is particularly high. This is considered to be because when the molded body is exposed to a high temperature, the thermoplastic resin quickly softens, so that the low-melting glass melted in the molded body easily moves to the surface of the molded body.

  Particularly preferred examples of the thermoplastic resin include polyester resins and polyolefin resins. Only one of the polyester resin and the polyolefin resin may be used, or both may be used in combination.

  Specific examples of the polyester resin include polyethylene terephthalate, polycarbonate, polybutylene terephthalate, polycyclohexadimethylene terephthalate, and polyarylate. Particularly preferred polyester resins include polybutylene terephthalate and polycarbonate. Among these polyester resins, only one kind may be used or a plurality of kinds may be used in combination.

  Specific examples of polyolefin resins include homopolymers such as polyethylene, polypropylene, polystyrene, polyacrylic acid ester, polymethacrylic acid ester, poly 1-butene, poly 1-pentene and polymethyl pentene; ethylene / α-olefin copolymer Vinyl alcohol ester homopolymer; polyolefin obtained by complete or partial hydrolysis of vinyl alcohol ester; complete or partial hydrolysis of a copolymer of at least one of ethylene and propylene and vinyl alcohol ester A copolymer of at least one of ethylene and propylene and at least one of an unsaturated carboxylic acid and an unsaturated carboxylic acid ester; at least one of ethylene and propylene, an unsaturated carboxylic acid and an unsaturated carbo At least part of the carboxyl groups of the copolymer of ester of a polyolefin obtained by metal chlorides; and block copolymers and hydrides of the conjugated diene and the vinyl aromatic hydrocarbons. Particularly preferred polyolefin systems include polyethylene and polypropylene. Among these polyolefin-based resins, only one type may be used or a plurality of types may be used in combination.

The low melting point glass is preferably composed of an organic or inorganic glass compound having a softening point in the range of 150 ° C to 800 ° C. The softening point of the low-melting glass is a temperature at which an endothermic peak appears upon melting, and is measured by a differential scanning calorimetry. Specific examples of the glass compound include SiO ₂ , B ₂ O ₃ , P ₂ O ₅ , PbO, TiO ₂ , CdO, Tl ₂ O, Bi ₂ O ₃ , CuO, V ₂ O ₅ , Al ₂ O ₃ , Ga _2. Examples thereof include organic or inorganic glass compounds containing O ₃ , ZnO ₂ , Y ₂ O ₃ , ZrO ₂ , Fe ₂ O ₃ , alkali metal oxides, alkaline earth metal oxides, and the like. The kind and composition ratio of the glass compound constituting the low melting point glass are appropriately adjusted so that the low melting point glass has a desired softening point. The low melting point glass is preferably in the form of particles. Although there is no restriction | limiting in the particle size of low melting glass, It is preferable that especially the average particle diameter of low melting glass is the range of 0.5 micrometer-10 micrometers. This average particle diameter is a value derived from the particle diameter observed by SEM (scanning electron microscope). If this average particle size is 0.5 μm or more, aggregation of particles of low melting point glass in the thermosetting resin composition is suppressed and the dispersibility of these particles is improved, and this average particle size is 10 μm or less. If it exists, the dispersibility of the low melting glass in a flame-retardant resin composition will become very high.

  The average particle size of the inorganic filler is 100 nm or less as described above. This average particle diameter is a number average particle diameter measured by a laser diffraction / light scattering method, and is measured, for example, using model number SALD3000 manufactured by Shimadzu Corporation and using isopropyl alcohol as a dispersion. Although the lower limit of the average particle size of the inorganic filler is not limited, the average particle size of the inorganic filler should be 10 nm or more in consideration of availability, dispersibility of the inorganic filler in the flame retardant resin composition, and the like. Is preferred. In particular, the average particle size of the inorganic filler is preferably in the range of 50 nm to 90 nm, or the inorganic filler has a particle size distribution in which the number of particles having a particle size of 50 nm to 90 nm is 68% or more of the total number of particles. It is preferable. This particle size distribution is measured using, for example, model number SALD3000 manufactured by Shimadzu Corporation as in the case of the average particle size.

  The kind of the inorganic filler is not limited, but is preferably at least one selected from magnesium hydroxide, magnesium oxide, aluminum hydroxide, and aluminum oxide. Since these inorganic fillers are basic oxides or hydroxides, the formation of char is particularly accelerated by the inorganic filler when the molded body is heated, thereby further improving the flame retardancy of the molded body. To do.

  It is preferable that the inorganic filler does not substantially cause a melting phenomenon in a temperature range lower than the temperature at which the matrix resin burns, and particularly preferably does not substantially cause a melting phenomenon in a temperature range of 800 ° C. or lower. The temperature at which the melting phenomenon does not substantially occur is a temperature below the melting point of the inorganic filler, and even if the temperature is higher than the melting point of the inorganic filler, the inorganic filler is thermally affected by a chemical reaction such as dehydration at that temperature. Refers to the temperature changing to a more stable substance. For example, magnesium oxide and aluminum oxide are stable and have high heat resistance, and do not melt at a temperature of 800 ° C. or lower. Further, magnesium hydroxide has a melting point of 350 ° C. and aluminum oxide has a melting point of 300 ° C. When heated, magnesium hydroxide is converted to magnesium oxide and aluminum hydroxide is oxidized by a dehydration reaction at a temperature below the melting point. Since it changes to aluminum, magnesium hydroxide and aluminum hydroxide do not substantially cause a melting phenomenon in a temperature range of 800 ° C. or lower. The temperature at which the matrix resin burns is usually 400 ° C. or higher, but at such temperatures, the magnesium hydroxide and aluminum hydroxide are changed to magnesium oxide and aluminum oxide, so the temperature is lower than the temperature at which the matrix resin burns. It does not melt in the area.

  The inorganic filler is preferably subjected to a surface treatment with a silane coupling agent. In this case, the generation of drip is further suppressed during the burning of the molded body. This is because the dispersibility of the inorganic filler in the flame retardant resin composition and the molded body is improved, so that the aggregation of the inorganic filler is suppressed, thereby reducing the effective surface area of the inorganic filler. This is considered to be because of this.

  Although it does not specifically limit as a silane coupling agent, For example, epoxy, such as (gamma) -glycidoxypropyl trimethoxysilane, (gamma) -glycidoxypropyl triethoxysilane, (beta)-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, etc. Silane; γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, γ- Aminosilanes such as ureidopropyltriethoxysilane; mercaptosilanes such as 3-mercaptopropyltrimethoxysila; p-styryltrimethoxysilane, vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltrimethoxysilane, vinyl Examples include vinyl silanes such as triethoxysilane and γ-methacryloxypropyltrimethoxysilane; and other polymer type silanes such as epoxy, amino, and vinyl.

  As above-mentioned, the ratio of low melting glass is the range of 1-40 mass parts, and the ratio of an inorganic filler is the range of 1-40 mass parts with respect to 100 mass parts of matrix resins in a flame-retardant resin composition. In such a range, the molded product has high flame retardancy, and the mechanical properties of the molded product are maintained sufficiently high. In order for the flame retardancy of the molded product to be particularly high, the proportion of the low-melting glass is particularly preferably 5 parts by mass or more, and the proportion of the inorganic filler is particularly preferably 20 parts by mass or more. Furthermore, in order for the flame retardancy of the molded body to be particularly high, the ratio of the total amount of the low-melting glass and the inorganic filler to 100 parts by mass of the matrix resin is preferably 20 parts by mass or more, and 30 parts by mass or more. More preferably.

  As described above, the mass ratio of the former to the latter of the low-melting glass and the inorganic filler in the flame-retardant resin composition is in the range of 1: 4 to 1: 1, which makes the molded body extremely flame-retardant. To be high. This is considered to be because the movement of small bubbles and the movement of large bubbles in the molded body are inhibited in a well-balanced manner when the ratio between the low melting point glass and the inorganic filler is in the above range. If the ratio of the low-melting glass to the inorganic filler is smaller than the above range, the flame retardancy of the molded product is lowered. This is considered because the film formed by the drip phenomenon does not sufficiently inhibit the movement of small bubbles. On the other hand, when the ratio of the inorganic filler to the low-melting glass is smaller than the above range, the flame retardancy of the molded article is lowered. This is presumably because the movement of large bubbles is not sufficiently inhibited by the layer composed of the inorganic filler, and the drip phenomenon is not sufficiently suppressed.

  In addition to the above components, the flame retardant resin composition may contain appropriate additives employed in molding resin compositions and the like. The type and content of the additive are preferably set as appropriate so as not to hinder the flame retarding action of the low-melting glass and the inorganic filler.

  The flame retardant resin composition according to the present embodiment is produced by blending and mixing the above components by an appropriate technique. The flame retardant resin composition may be prepared in an appropriate shape such as a tablet as necessary.

  Although the use of the molded object formed from a flame-retardant resin composition is not specifically limited, It can be used suitably for the use for which especially mechanical strength and a flame retardance are calculated | required. Specific examples of uses of the flame retardant resin composition include power supply parts, light reflector covers, power supply terminal parts, and the like.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples, and can be implemented with appropriate modifications within a range that can be adapted to the gist of the present invention, all of which are within the technical scope of the present invention. Is included.

[Examples 1-4, 6, 7, Comparative Examples 1-5]
The matrix resin, low melting point glass, and inorganic filler shown in Table 1 below are blended in the proportions shown in Table 1 below, and the resulting mixture is kneaded with a twin screw extruder (manufactured by Toyo Seiki Co., Ltd.). After melting, it was air-cooled, and the resulting product was cut with a pelletizer to obtain a pellet-shaped resin composition.

[Example 5]
In Example 1, the silane coupling agent treatment was performed in advance on the inorganic filler before blending in the mixture. In this silane coupling agent treatment, vinyltrichlorosilane (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the silane coupling agent, and the amount of adhesion to the inorganic filler was 5 mass% with respect to the inorganic filler. The other conditions were the same as in Example 1. Thereby, a pellet-shaped resin composition was obtained.

[Evaluation test]
-Flame retardance The resin composition by each Example and a comparative example was shape | molded, the test piece (dimension 1.2mmx130mmx13mm) was produced, and the combustion test by UL94 specification was done about this test piece. The results are as shown in Table 1.

-Tensile strength In Examples 1-7 and Comparative Examples 1-5, while changing the ratio of an inorganic filler to 100 mass% with respect to a matrix resin, a low melting glass is not used, and other conditions are Example 1. Standard samples corresponding to each of the examples and comparative examples were prepared by making the same as those of -7 and Comparative Examples 1-5.

  A resin composition obtained in each example and comparative example, and a standard sample corresponding to each example and comparative example were molded to produce a test piece, and the test piece was subjected to a method in accordance with JIS K7113. A tensile test was performed and the tensile elongation at break was measured. The test conditions were an inter-test distance of 115 mm and a tensile speed of 1 mm / min.

  When the tensile break elongation of the test piece formed from the resin composition according to each example and comparative example is 150% or more of the tensile break elongation of the test piece formed from the standard sample, “◯”, less than 150% Some cases were evaluated as “x”. The results are as shown in Table 1.

Details of the components shown in Table 1 are as follows.
Matrix resin 1: Polymethyl methacrylate resin (PMMA resin), manufactured by Wako Pure Chemical Industries, Ltd.
-Matrix resin 2: Polyethylene resin (PE resin), manufactured by Prime Polymer Co., Ltd., trade name Hi-Zex.
Low melting glass: PbO ₂ —B ₂ O ₃ glass, average particle size 3.5 μm, softening point 430 ° C., manufactured by Nippon Electric Glass Co., Ltd., product number GA-2v.
-Inorganic filler 1: Magnesium hydroxide particles, average particle size 70 nm, 68% of the number of particles in the range of 50 nm to 90 nm in particle size relative to the total number of particles, manufactured by Wako Pure Chemical Industries, Ltd.
Inorganic filler 2: Magnesium hydroxide particles, average particle size 600 nm, manufactured by Wako Pure Chemical Industries, Ltd.

  According to the results shown in Table 1, the evaluations of the tensile strength of the test pieces formed from the resin compositions according to Examples 1 to 7 are all “◯”, so that these test pieces are matrix resins. It was confirmed that the high mechanical strength of was sufficiently maintained.

  Furthermore, the test pieces formed from the resin compositions according to Examples 1 to 7 all achieved flammability class V-0 as a result of the combustion test according to the UL94 standard. On the other hand, all the test pieces formed from the resin compositions according to Comparative Examples 1 to 4 achieved only the flammability class V-2. In Comparative Example 5, the tensile strength was evaluated as “x”. It was.

Claims (3)

It contains an inorganic filler other than the matrix resin, the low-melting glass, and the low-melting glass, and the ratio of the low-melting glass to 100 parts by weight of the matrix resin is in the range of 1 to 40 parts by weight, with respect to 100 parts by weight of the matrix resin The ratio of the inorganic filler is in the range of 1 to 40 parts by mass, the mass ratio of the former to the latter of the low-melting glass and the inorganic filler is in the range of 1: 4 to 1: 1, and the inorganic filling The material is magnesium hydroxide particles having an average particle diameter of 100 nm or less, the low-melting glass is particulate, and the average particle diameter is in the range of 0.5 μm to 10 μm.   The flame-retardant resin composition according to claim 1, wherein a surface of the inorganic filler is coated with a silane coupling agent. The flame retardant resin composition according to claim 1, wherein the matrix resin is a thermoplastic resin .