JP2018090695A - Arc resistant bmc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arc resistance bulk molding compound (BMC) and an electric/electronic component obtained by curing the compound.SOLUTION: A bulk molding compound (BMC) is a thermosetting resin composition containing (a) unsaturated polyester, (b) a monomer having one or more polymerizable carbon-carbon double bonds, (c) aluminum hydroxide, (d) a chopped strand glass fiber, (e) a low constrictive agent and (f) a curing agent, wherein a content of (c) the aluminum hydroxide is 300-590 pts.mass with respect to 100 pts.mass of the total amount of (a) the unsaturated polyester and (b) the monomer, and a content of (d) the chopped strand glass fiber is 10-200 pts.mass with respect to 100 pts.mass of the total amount of (a) the unsaturated polyester and (b) the monomer. It is preferable that the BMC further contains 0.2-30 pts.mass of (g) a compound containing a phosphate group with respect to 100 pts.mass of the total amount of (a) the unsaturated polyester and (b) the monomer.SELECTED DRAWING: None

Description

  The present invention relates to an unsaturated polyester resin composition, particularly a bulk molding compound (BMC), and an electric / electronic component obtained by curing them, having significantly improved arc resistance.

  Fiber reinforced plastic with glass fiber dispersed in binder resin as a dispersion reinforcing material is inexpensive and has excellent heat resistance, flame resistance, tracking resistance, etc., so it has been used for various structural materials and insulating materials. Yes. In particular, bulk molding compounds (BMC) using unsaturated polyester are used in various electrical insulating product members because they are excellent in moldability, electric greenness and arc resistance. Such an electrically insulating molded body can absorb the energy of an arc generated when an electrode such as an electric switch is opened and closed, and has a function of protecting an electrical device from the arc.

  In recent years, with the miniaturization and weight reduction of electric devices, there has been an increasing demand for miniaturization and high capacity of electric switches. The electrical insulating molded body is also required to have high performance in terms of arc resistance, and various solutions have been proposed. For example, it is known that arc resistance is improved when a large amount of a flame retardant filler that releases water at a high temperature such as aluminum hydroxide is contained. Document 1 proposes that an arc-resistant molded article is obtained by curing a sheet-like material comprising an inorganic sheet and an inorganic binder composition. Document 2 proposes that an prepreg using an epoxy resin composition containing aluminum oxide is cured to obtain an arc-resistant electrically insulating molded body. Document 3 proposes that an arc-resistant electric insulation molded body is obtained by curing a prepreg containing a binder resin and a filler.

JP-A-8-36938 JP-A-9-207270 JP 2005-89648 A

However, in these prior documents, the amount of reinforcing fibers and fillers is large, so that the prepreg is impregnated with the resin composition impregnated into the fibers from the viewpoint of handleability such as viscosity. In order to obtain a thick molded product, it is necessary to laminate a plurality of layers of reinforcing fibers and a resin composition, and productivity is lowered. In addition, the obtained molded article has a problem that anisotropy of mechanical strength occurs depending on the direction of the reinforcing fiber. Furthermore, a prepreg containing a large amount of filler generally requires a diluting solvent such as water and ketones in the production process, and it is necessary to remove the solvent in a subsequent process. On the other hand, the conventional BMC generally has a smaller amount of reinforcing fibers than the prepreg, and the resin occupies the whole, so that there is a problem that arc resistance comparable to that of the prepreg cannot be obtained. Therefore, there has been a demand for an invention for an electrical / electronic component that has no strength anisotropy, can be easily molded with a uniform molding operation, and has excellent arc resistance using BMC, which is a kneaded body containing no solvent. .
An object of the present invention is to provide a BMC that provides a molded article having excellent workability and moldability, good productivity, no anisotropy in strength, and excellent arc resistance.

  As a result of diligent research to solve the above problems, the present inventors have blended aluminum hydroxide and glass fiber at a certain ratio, so that BMC having high arc resistance and containing no diluent solvent can be obtained. As a result, the present invention was completed.

That is, the present invention includes the following [1] to [7].
[1] (a) unsaturated polyester, (b) monomer having one or more polymerizable carbon-carbon double bonds, (c) aluminum hydroxide, (d) chopped strand glass fiber, (e) low shrinkage agent, (F) A thermosetting resin composition containing a curing agent, wherein the content of (c) aluminum hydroxide is 100 parts by mass of the total amount of (a) unsaturated polyester and (b) monomer. 300 to 590 parts by mass, and the content of the (d) chopped strand glass fiber is 10 to 200 parts by mass with respect to 100 parts by mass of the total amount of the (a) unsaturated polyester and the (b) monomer. Characteristic bulk molding compound (BMC).
[2] The BMC according to [1], wherein the BMC contains (g) a compound having a phosphate group.
[3] The content of the compound (g) having a phosphate ester group is 0.2 to 30 parts by mass with respect to 100 parts by mass of the total amount of the (a) unsaturated polyester and the (b) monomer. BMC of [1] or [2].
[4] The BMC according to any one of [1] to [3], wherein the average particle diameter of the (c) aluminum hydroxide is 15 μm or less.
[5] The BMC according to any one of [1] to [4], wherein the fiber length of the (d) chopped strand glass fiber is 1 mm to 20 mm.
[6] The BMC according to any one of [1] to [5], wherein the (a) unsaturated polyester has a mass average molecular weight of 2,000 to 50,000.
[7] The content of the (b) monomer is 25 to 70% by mass with respect to a total of 100% by mass of the (a) unsaturated polyester and the (b) monomer, according to [1] to [6] BMC in any one.
[8] A cured product obtained by curing the BMC according to any one of [1] to [7].

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in workability | operativity and a moldability, can be manufactured with sufficient productivity, can provide the BMC which gives the molded article which is excellent in arc resistance in strength without anisotropy.

  The BMC of the present invention comprises (a) an unsaturated polyester, (b) a monomer having one or more polymerizable carbon-carbon double bonds, (c) aluminum hydroxide, (d) chopped strand glass fiber, (e) low A thermosetting resin composition containing a shrinking agent and (f) a curing agent. Hereinafter, each component will be described.

[(A) Unsaturated polyester]
(A) Unsaturated polyester used for this invention is not specifically limited, The well-known thing used for the molding material in the said technical field can be used. (A) The unsaturated polyester is generally a compound obtained by polycondensation (esterification) of a polyhydric alcohol with an unsaturated polybasic acid or a saturated polybasic acid. In addition, in the range which does not inhibit the effect of this invention, you may use a vinyl ester for a part of (a) unsaturated polyester.

The mass average molecular weight (MW) of the unsaturated polyester is not particularly limited, but is preferably 2,000 to 50,000, more preferably 3,000 to 30,000, and further preferably 5,000 to 20,000. . If the mass average molecular weight is 2,000 or more, the strength after curing is good, and if it is 50,000 or less, the viscosity of the composition is preferable as BMC. In this specification, “mass average molecular weight” is measured at normal temperature using gel permeation chromatography (Shodex GPC-101, Showa Denko KK) at the following conditions, and obtained using a standard polystyrene calibration curve. Means the value.
Column: Showa Denko LF-804
Column temperature: 40 ° C
Sample: (a) 0.2 parts by mass of unsaturated polyester in tetrahydrofuran flow rate: 1 mL / min Eluent: tetrahydrofuran Detector: RI-71S

  The polyhydric alcohol used for the synthesis of the unsaturated polyester is not particularly limited, and known ones can be used. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, pentanediol, hexanediol, neopentanediol, hydrogenated bisphenol A, bisphenol A, and glycerin. It is done. These can be used alone or in combination.

  The unsaturated polybasic acid used for the synthesis of the unsaturated polyester is not particularly limited, and known ones can be used. Examples of unsaturated polybasic acids include maleic anhydride, fumaric acid, citraconic acid, itaconic acid and the like. These can be used alone or in combination.

  The saturated polybasic acid used for the synthesis of the unsaturated polyester is not particularly limited, and known ones can be used. Examples of saturated polybasic acids include phthalic anhydride, isophthalic acid, terephthalic acid, het acid, succinic acid, adipic acid, sebacic acid, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, and endomethylenetetrahydrophthalic anhydride. Is mentioned. These can be used alone or in combination.

  Unsaturated polyester is compoundable by a well-known method using the above raw materials. Various conditions in this synthesis need to be set as appropriate according to the raw material used and the amount thereof, but in general, in an inert gas stream such as nitrogen, at a temperature of 140 to 230 ° C. under pressure or reduced pressure. Can be esterified. In this esterification reaction, an esterification catalyst can be used as needed. Examples of the catalyst include known catalysts such as manganese acetate, dibutyltin oxide, stannous oxalate, zinc acetate, and cobalt acetate. These can be used alone or in combination.

[(B) Monomer having one or more polymerizable carbon-carbon double bonds]
The monomer (b) having at least one polymerizable carbon-carbon double bond used in the present invention is a component that acts as a crosslinking agent for (a) an unsaturated polyester. (B) The monomer having at least one polymerizable carbon-carbon double bond is not particularly limited as long as it has at least one polymerizable carbon-carbon double bond polymerizable with the unsaturated polyester. Never happen.

(B) Examples of monomers having one or more polymerizable carbon-carbon double bonds include styrene, vinyltoluene, methylstyrene, and methyl methacrylate as monofunctional monomers, and ethylene glycol dimers as polyfunctional monomers. (Meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol # 200 (# 400, # 600) di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) ) Acrylate, 1,9-nonanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerin di (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl (meth) acrylate, triethylene glycol di (Meta) a Relate, polyethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, and 1,10-decanediol di (meth) acrylate. These can be used alone or in combination. From the viewpoint of moldability of BMC, preferably, styrene, vinyl toluene, and ethylene glycol di (meth) acrylate are exemplified, and styrene is particularly preferable.
In the present specification, “(meth) acrylate” means methacrylate or acrylate.

  The blending amount of the component (b) in the BMC of the present invention is preferably 25 to 70% by mass, more preferably 30 to 65% by mass, with respect to 100% by mass of the total amount of the components (a) and (b). More preferably, it is 35-65 mass%. If the amount of the crosslinking agent is 25% by mass or more, the resin viscosity is appropriate and sufficient workability can be obtained. On the other hand, if the amount of component (b) is 70% by mass or less, sufficient strength as BMC can be obtained.

[(C) Aluminum hydroxide]
Aluminum hydroxide is used as an inorganic filler. The content of aluminum hydroxide is preferably 300 to 590 parts by mass, and 320 to 580 parts by mass with respect to 100 parts by mass of the total amount of component (a) and component (b) from the viewpoint of arc resistance. Is more preferable, and 350 to 550 parts by mass is particularly preferable. If it is 300 parts by mass or more, the arc resistance is good, and if it is 590 parts by mass or less, the kneadability is good, which is preferable.

  The (c) aluminum hydroxide has an average particle size of at least 0.5 μm. The average particle diameter is a median diameter measured with a laser diffraction / scattering particle size distribution measuring apparatus (Microtrack Bell, FRA). If it is 0.5 μm or more, the viscosity is appropriate, and a moldable resin can be obtained. From the viewpoint of moldability, the average particle diameter of aluminum hydroxide is more preferably 0.7 μm or more, and further preferably 1.8 μm or more. On the other hand, the average particle diameter is preferably 15 μm or less, more preferably 12 μm or less, and further preferably 10 μm or less, from the surface smoothness and mechanical properties of the molded product. If it is 15 μm or less, the surface smoothness and mechanical strength of the molded article are good, the fluidity of the material is appropriate, and the moldability is excellent.

[(D) Chopped strand glass fiber]
(D) Chopped strand glass fiber used for this invention is not specifically limited, The well-known thing used for the molding material in the said technical field can be used. Chopped strand glass fibers can be obtained by combining glass fibers with a sizing agent and cutting them. (D) The fiber length of the chopped strand glass fiber is preferably 1 mm to 20 mm, more preferably 1.5 mm to 15 mm, and particularly preferably 1.5 mm to 13 mm. If the fiber length is 20 mm or less, the in-mold fluidity of the BMC is appropriate, and if it is 1 mm or more, the viscosity is excellent in handleability. The fiber length is a number average value obtained by measuring 100 fibers randomly collected with a caliper or a micrometer of an optical microscope.

  Although the compounding quantity of (d) component in BMC of this invention is not specifically limited, Preferably it is 10-200 mass parts with respect to a total of 100 mass parts of (a) component and (b) component, More preferably, 20- 180 parts by mass, particularly preferably 25 to 160 parts by mass. If the compounding amount of the component (d) is 10 parts by mass or more, the mechanical strength of the cured product is good, and if the compounding amount of the component (d) is 200 parts by mass or less, each component is produced when manufacturing BMC. Is easy to mix.

[(E) Low shrinkage agent]
The (e) low shrinkage agent used in the present invention is not particularly limited, and those known in the technical field can be used. (E) Examples of the low shrinkage agent include thermoplastic polymers generally used as low shrinkage agents such as polystyrene, polymethyl methacrylate, polyvinyl acetate, saturated polyester, and styrene-butadiene rubber. These can be used alone or in combination. In addition, it is preferable to use polystyrene as the low shrinkage agent from the viewpoint of low shrinkage.

  The amount of the (e) low-shrink agent in the BMC of the present invention is not particularly limited, but is preferably 3 to 70 parts by mass, more preferably 100 parts by mass with respect to the total of (a) component and (b) component. It is 10-60 mass parts, Most preferably, it is 15-50 mass parts. If the blending amount of the low shrinkage agent is 3 parts by mass or more, molding shrinkage of the cured product can be suppressed. If the blending amount of the low shrinkage agent is 70 parts by mass or less, the in-mold fluidity of BMC is appropriate, and problems such as unfilling and damage to insert parts can be suppressed.

[(F) Curing agent]
The (f) curing agent used in the present invention is not particularly limited, and a radical polymerization initiator known in the art can be selected. As the radical polymerization initiator, an organic peroxide, an azo initiator, a redox initiator, or the like can be used. Among these, from the viewpoint of reaction efficiency, it is preferable to use an organic peroxide. Examples of organic peroxides include t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy-2 -Ethyl hexanate, benzoyl peroxide, 1,1-di-t-butylperoxycyclohexane, 1,1-di-t-hexylperoxycyclohexane, 1,1-di-t-butylperoxy-3,3 , 5-trimethylcyclohexane, t-butylperoxyisopropyl carbonate, t-hexylperoxyisopropyl carbonate, t-butylperoxybenzoate, t-hexylperoxybenzoate, 1,6-bis (t-butylperoxycarbonyloxy ) Hexane, dicumyl peroxide, and di-t-butyl peroxide Organic peroxides such as de like. These can be used alone or in combination.

  The blending amount of the component (f) in the BMC of the present invention is preferably 0.1 to 15 parts by mass, more preferably 1 to 10 parts by mass with respect to 100 parts by mass in total of the components (a) and (b). Particularly preferably, it is 2 to 6 parts by mass. (F) If the compounding quantity of a component is 0.1 mass part or more, poor curing can be suppressed. (F) If the compounding quantity of a component is 15 mass parts or less, storage stability is favorable.

The thermosetting resin composition of the present invention contains the above components (a) to (f) as essential components, but other components can be blended from the viewpoint of enhancing desired physical properties. Other components are not particularly limited, and components generally used in thermosetting resin compositions can be blended. For example, (g) a compound having a phosphate ester group, (h) a mold release agent, (i) a polymerization inhibitor, (j) a thickener, (k) a colorant, (l) hydroxylation Examples include inorganic fillers other than aluminum.

[(G) Compound having phosphate group]
In the present invention, it is preferable to add a compound having a phosphate group. The compound having a phosphate ester group can be adsorbed on the surface of (c) aluminum hydroxide to improve the wettability of the aluminum hydroxide particle surface and the dispersion stability between the particles, and can increase the filling property. . The compound having a phosphate ester group is not particularly limited, and examples thereof include a copolymer of a saturated polyester having a phosphate ester bond, and trade names of BYK-W985, W995, W996, and W9010 (BYK Chemie). (Commercially available) can also be used.

  (G) Content of the compound which has a phosphate ester group is 0.2-30 mass parts with respect to 100 mass parts of total amounts of (a) component and (b) component, More preferably, it is 0.5. It is -20 mass parts, Most preferably, it is 1-15 mass parts.

  When the content of the component (g) is 0.5 parts by mass or more with respect to 100 parts by mass of the total amount of the components (a) and (b), (c) the aluminum hydroxide filling property is improved (heat (C) Increasing the content of aluminum hydroxide in the curable resin composition). On the other hand, when the content of the component (g) is 30 parts by mass or less, the arc resistance of the cured product of the present invention is sufficiently maintained.

  The type of inorganic filler other than (h) mold release agent, (i) polymerization inhibitor, (j) thickener, (k) colorant, and (l) aluminum hydroxide is not particularly limited, A well-known thing can be used in the said technical field.

  (H) Examples of the mold release agent include stearic acid, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, carnauba wax and the like. (H) The compounding quantity of a mold release agent is 0.2-50 mass parts with respect to 100 mass parts of total amounts of (a) component and (b) component, More preferably, it is 1-40 mass parts. Especially preferably, it is 3-30 mass parts. If the amount of component (h) is 0.2 or more, sufficient release properties can be obtained. If the amount of component (h) is 50 parts by mass or more, the moldability may be inferior.

  The (i) polymerization inhibitor used in the present invention is not particularly limited, and those known in the technical field can be used. For example, quinones such as parabenzoquinone, tolquinone, naphthoquinone, phenanthraquinone, and 2,5 diphenylparabenzoquinone; tolhydroquinone, hydroquinone, tertiary butylcatechol, monotertiarybutyl hydroquinone, and 2,5 ditertiarybutyl hydroquinone Hydroquinones such as hydroquinone; and monophenols such as hydroquinone monomethyl ether and 2,6-di-t-butyl-p-cresol. These can be used alone or in combination. Of these, quinones are preferably used from the viewpoint of suppressing gelation.

  (I) The compounding quantity of a polymerization inhibitor becomes like this. Preferably it is 0.005-0.2 mass part with respect to a total of 100 mass parts of (a) component and (b) component, More preferably, it is 0.01-0. .1 part by mass. (I) If the compounding quantity of a component is 0.005 mass part or more with respect to a total of 100 mass parts of (a) component and (b) component, BMC which has desired in-mold fluidity | liquidity will be obtained. On the other hand, if the blending amount of component (i) is 0.2 parts by mass or less, curing time and curing after a certain time are sufficient.

  (J) Examples of the thickener include metal oxides such as magnesium oxide, magnesium hydroxide, calcium hydroxide, and calcium oxide, and isocyanate compounds. These components can be used alone or in combination.

  (K) The colorant is used when it is necessary to color a molded article, and various inorganic pigments and organic pigments that are usually used in bulk molding compounds can be used. What is necessary is just to adjust the usage-amount of a coloring agent suitably according to the coloring degree of a molded article.

(L) As inorganic fillers other than aluminum hydroxide, powdery substances such as alumina, wollastonite, clay, talc, mica, and silicic anhydride can be used as necessary. Among these, calcium carbonate is preferable from the viewpoint of surface smoothness and heat resistance of the resin composition.
(L) It is preferable that the compounding quantity of inorganic fillers other than aluminum hydroxide is 1-500 mass parts with respect to 100 mass parts of total amounts of (a) component and (b) component, and 1-300 mass parts It is more preferable that it is 1 to 200 parts by mass. If the amount is 500 parts by mass or less, the kneadability is good.

  In addition, if the compounding quantity of said arbitrary component (h) component, (i) component, (j) component, and (k) component is a range which does not inhibit the effect of this invention, it will not specifically limit.

  The BMC of the present invention can be produced by blending and kneading the aforementioned predetermined amounts of each component by a known method. For example, a BMC can be obtained by putting a predetermined amount of each component into a kneader and mixing them.

  Since the BMC of the present invention thus obtained can improve the curability without impairing the storage stability, it is possible to improve the workability and productivity when producing a cured product having a desired shape. It becomes.

Since the BMC of the present invention provides a cured product having high arc resistance and mechanical strength, it can be used as a highly reliable material for electric and electronic parts. In addition, when using BMC for an electrical / electronic component, the arc resistance according to JIS-K6911 (1995) is preferably 185 seconds or more, more preferably 188 seconds or more, and particularly preferably 190 seconds or more. Further, the mechanical strength in the case of using BMC for electrical and electronic parts is preferably 30 MPa or more, more preferably 35 MPa or more, and particularly preferably 37 MPa or more, based on JIS-K7113 (1995).

There are no particular limitations on the method for molding the electric / electronic component, and the BMC of the present invention is molded by molding means such as compression molding, transfer molding, and injection molding, and then cured to obtain the electric / electronic component. can get. Specifically, after the BMC of the present invention is put into a mold by various means, it may be cured by heating and pressurizing to a predetermined temperature.
The curing conditions may be appropriately set according to the raw material used for the BMC of the present invention, but generally the curing temperature is 120 to 160 ° C. and the curing time is 1 to 30 minutes.

  The BMC of the present invention is particularly suitable for use as a material for electrical and electronic parts that require a high degree of arc resistance because it gives a cured product having high arc resistance. That is, the electric / electronic component formed by molding the BMC of the present invention is excellent in arc resistance and can be manufactured with good workability and productivity.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited by these.

(Examples 1-6, Comparative Examples 1-6)
(Synthesis of unsaturated polyester resin)
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas inlet tube and a thermometer, 100 mol of propylene glycol, 30 mol of phthalic anhydride, and 70 mol of maleic anhydride are charged, and an acid value of 20 mgKOH / The reaction was continued until g. Next, 0.015 parts by mass of hydroquinone was added to 100 parts by mass of the reaction product and cooled to 160 ° C., and then a styrene monomer was further added to obtain an unsaturated polyester resin. Here, the styrene monomer was added so as to be 30 parts by mass in the unsaturated polyester resin. Moreover, it was 15,000 when the weight average molecular weight (MW) of unsaturated polyester was measured on said conditions.

The unsaturated polyester resin obtained above and each component shown in Table 1 were kneaded at 25 ° C. for 30 minutes at the ratio shown in Tables 2 and 3 at 25 ° C. to obtain BMC. In Tables 2 and 3, the styrene monomer is the total amount of the amount added during the production of the unsaturated polyester resin and the amount added during the kneading. (A) The unsaturated polyester does not contain a styrene monomer.
In the blends of Comparative Example 1 and Comparative Example 2, the composition was not collected during kneading, and a uniform kneaded product was not obtained. In Tables 2 and 3, the unit of the amount of each component is part by mass.

  Next, the moldability, arc resistance, and tensile strength of the obtained BMC and its cured product were evaluated as follows. The results are shown in Tables 2 and 3.

(Evaluation of formability)
The obtained BMCs of Examples 1 to 6 and Comparative Examples 3 to 6 were molded into a flat plate of 100 mm × 100 mm × thickness 3 mm by injection molding at a molding temperature of 150 ° C., a molding pressure of 100 MPa, and a molding time of 3 minutes. The presence or absence of molding defects was confirmed by visual inspection. The case where a crack entered was confirmed as defective.

(Evaluation of arc resistance)
The obtained BMCs of Examples 1 to 6 and Comparative Examples 3 to 6 were molded into a flat plate of 100 mm × 100 mm × thickness 3 mm by injection molding at a molding temperature of 150 ° C., a molding pressure of 100 MPa, and a molding time of 3 minutes. The sample was cut into a circle having a diameter of 100 mm, and an arc resistance test in accordance with JIS-K6911 (1995) standard was performed.

(Evaluation of tensile strength)
Dumbbell-shaped test pieces of JIS-K7113 (1995) were produced by injection molding of the obtained BMCs of Examples 1 to 6 and Comparative Examples 3 to 6 at a molding temperature of 150 ° C., a molding pressure of 100 MPa, and a molding time of 3 minutes. -Tensile strength test of K7113 (1995) standard was performed.

  As shown in Tables 2 and 3, the BMCs of Examples 1 to 6 had good moldability, and a molded product in which the shape of the mold was transferred was easily obtained. Further, the BMCs of Examples 1 to 6 had an arc resistance of 190 seconds or more, and were excellent in arc resistance. In addition, the BMCs of Examples 1 to 6 had a tensile strength of 38 MPa or more, and had a strength suitable for use in electric and electronic parts. On the other hand, since the compositions of Comparative Examples 1 and 2 contained too many powders or chopped strand glass fibers, the materials were not collected during kneading, and a BMC having a uniform composition could not be obtained. The BMCs of Comparative Examples 3 to 5 had an arc resistance of 175 seconds or less, and the arc resistance was inferior. The BMC of Comparative Example 6 had a tensile strength of 25 MPa and was inferior in strength.

  As can be seen from the above results, according to the present invention, it is possible to produce a BMC having good and general formability with good workability and productivity, and to obtain a cured product with excellent arc resistance, By using the cured product, an electric / electronic component having excellent arc resistance can be provided.

Claims (8)

(A) unsaturated polyester, (b) monomer having one or more polymerizable carbon-carbon double bonds, (c) aluminum hydroxide, (d) chopped strand glass fiber, (e) low shrinkage agent, (f) A thermosetting resin composition containing a curing agent, wherein the content of the (c) aluminum hydroxide is 300 to 590 with respect to 100 parts by mass of the total amount of the (a) unsaturated polyester and the (b) monomer. The content of the (d) chopped strand glass fiber is 10 to 200 parts by mass with respect to 100 parts by mass of the total amount of the (a) unsaturated polyester and the (b) monomer. Bulk molding compound (BMC). The BMC according to claim 1, wherein the BMC contains (g) a compound having a phosphate group. Content of the compound which has the said (g) phosphate ester group is 0.2-30 mass parts with respect to 100 mass parts of total amounts of the said (a) unsaturated polyester and the said (b) monomer, Claims The BMC according to 1 or 2. BMC in any one of Claims 1-3 whose average particle diameter of said (c) aluminum hydroxide is 15 micrometers or less. BMC in any one of Claims 1-4 whose fiber length of said (d) chopped strand glass fiber is 1 mm-20 mm. The BMC according to any one of claims 1 to 5, wherein the (a) unsaturated polyester has a mass average molecular weight of 2,000 to 50,000. The content of the (b) monomer is 25 to 70% by mass with respect to a total of 100% by mass of the (a) unsaturated polyester and the (b) monomer, according to any one of claims 1 to 6. BMC. A cured product obtained by curing the BMC according to any one of claims 1 to 7.