JP2020007463A - Addition curable raw material composition - Google Patents

Abstract

To improve storage stability of the addition curable raw material composition containing an iron-containing powder, to provide a raw material composition hardly generating curing inhibition, and to provide an addition curable raw material composition suitable to a master batch.SOLUTION: An addition curable raw material composition contains a polymer, a curing catalyst, and an iron-containing powder, the iron-containing powder is at least one selected from iron, iron oxide, and metal oxide containing iron, the iron-containing powder is surface treated by at least one coupling agent selected from a titanium-based coupling agent, an aluminum-based coupling agent and a silane-based coupling agent.SELECTED DRAWING: None

Description

  The present invention relates to an addition-curable raw material composition containing a surface-treated iron-containing powder.

  2. Description of the Related Art Conventionally, it has been known to mix an addition-curable polymer with an iron-containing powder to form a molded product for applications such as coloring, conducting, shielding electromagnetic waves, suppressing noise, and adjusting the dielectric constant. Patent Literature 1 proposes mixing an iron oxide filler as a colorant for a heat dissipation coating film. Patent Document 2 proposes an iron oxide filler, a zinc oxide powder, and the like as an adjustment of the dielectric constant of a resin molded product. Patent Document 3 proposes that a filler of an addition-curable silicone rubber is surface-treated with an organopolysiloxane having an average degree of polymerization of 2 to 50.

No. 2013-129677 JP-A-2005-28188 JP-T-2009-54157

  However, the addition-curable raw material composition containing the iron-containing powder of the prior art has a problem in storage stability. If there is a problem in storage stability, curing inhibition occurs, which leads to a problem that a good molded product cannot be obtained. Especially when used as a master batch, long-term storage was difficult.

  The present invention improves the storage stability of an addition-curable raw material composition containing an iron-containing powder, to provide a raw material composition that hardly inhibits curing, and is also suitable for a masterbatch. An addition-curable raw material composition is provided.

  The present invention is an addition-curable raw material composition containing a polymer, a curing catalyst, and an iron-containing powder, wherein the iron-containing powder is at least one selected from iron, iron oxide, and a metal oxide containing iron. An addition-curable raw material composition, wherein the iron-containing powder is surface-treated with at least one coupling agent selected from a titanium-based coupling agent, an aluminum-based coupling agent, and a silane-based coupling agent. Things.

  The present invention comprises a polymer, a curing catalyst and an iron-containing powder, wherein the iron-containing powder is at least one selected from iron, iron oxide, and a metal oxide containing iron, and the iron-containing powder is titanium. By being surface-treated with at least one coupling agent selected from an aluminum-based coupling agent, an aluminum-based coupling agent, and a silane-based coupling agent, the storage stability is improved, and the raw material composition is less likely to cause curing inhibition. The addition-curable raw material composition is suitable for a master batch that can be stored for a long period of time.

  The present invention is an addition-curable raw material composition containing a polymer (hereinafter, also referred to as “matrix resin”), a curing catalyst, and an iron-containing powder. The addition-curable polymer is usually divided into liquid A and liquid B, and one of them is added with a crosslinking component, and the other is added with a curing catalyst, for example, a platinum-based catalyst. I have. Usually, the A liquid and the B liquid are mixed, and if necessary, other components are added, mixed, molded, and cured. Curing is also referred to as crosslinking or vulcanization. Examples of such a polymer include silicone rubber, epoxy resin, polyether, and polyisobutylene, and any other polymer having an alkenyl group can be used. The addition curing mentioned here is a curing mechanism in which an alkenyl group and a Si—H group are chemically reacted by a hydrosilylation reaction. At this time, the hydrosilylation reaction can be caused by various methods, but it is common to use a metal catalyst, particularly a noble metal compound catalyst such as platinum. Particularly in the case of a curable composition, a platinum catalyst is often used.

  The iron-containing powder added as an additive in the present invention is at least one selected from iron, iron oxide, and a metal oxide containing iron. These are suitable for applications such as colorants, conductive materials, electromagnetic wave shielding materials, and noise suppression materials. In the present invention, the magnetic powder is excluded.

  The iron-containing powder of the present invention is surface-treated with at least one coupling agent selected from a titanium-based coupling agent, an aluminum-based coupling agent, and a silane-based coupling agent. Among them, a titanium-based coupling agent and an aluminum-based coupling agent are preferable. The surface treatment includes not only covalent bonding but also adsorption. When the surface treatment of the iron-containing powder is performed with the coupling agent, the surface of the iron-containing powder is covered with the coupling agent molecules, which is considered to prevent the adsorption of the curing catalyst, for example, the platinum-based catalyst. The surface treatment method of the coupling agent will be described later.

  The addition-curable raw material composition can be applied to a masterbatch for obtaining an addition-cured product molded body. Here, the masterbatch is a raw material composition used for coloring a molded product by adding a predetermined amount before or during molding of a resin or rubber, and the cost is lower than that of a general compound. It is characterized by good handleability. The masterbatch is usually stored as raw materials for about one week, and if necessary, the liquid A and the liquid B are mixed, and curing is advanced simultaneously with molding to form a molded article such as a sheet. The masterbatch of the present invention usually does not inhibit curing even when stored as raw materials for about one week.

  The addition-curable raw material composition of the present invention is preferably an organopolysiloxane. Organopolysiloxanes are cured into gums, rubbers, gels, putties, greases, and the like. There is a problem in that curing is inhibited at this time. Has improved this problem.

The titanium-based coupling agent is preferably at least one selected from isopropyl triisostearoyl titanate, diisostearoyl ethylene titanate, and a partial hydrolyzate thereof. The aluminum-based coupling agent is preferably at least one selected from alkyl acetoacetate aluminum diisopropylate and a partial hydrolyzate thereof. Further, the silane-based coupling agent includes R (CH ₃ ) _a Si (OR ′) _3-a (R is an alkyl group having 1 to 20 carbon atoms, R ′ is an alkyl group having 1 to 4 carbon atoms, and a is At least one selected from silane compounds represented by 0 or 1) and partial hydrolysates thereof is preferred.

The iron oxide is preferably at least one selected from triiron tetroxide (Fe ₃ O ₄ ) and diiron trioxide (Fe ₂ O ₃ ). These are useful as coloring materials, stabilizers, flame retardants, and the like. Of these, diiron trioxide (Fe ₂ O ₃ ) (ferric oxide in a generic name) has several crystal forms, such as α-iron oxide (such as red iron oxide) and β-iron oxide (with magnetism). Useful.

  The coupling agent is preferably added in an amount of 0.1 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, per 100 parts by mass of the iron-containing powder.

Examples of the surface treatment method of the coupling agent include (1) a dry method, (2) a wet method, and (3) an integral blend method.
(1) Dry method The dry method is a method in which an iron-containing powder is stirred by mechanical stirring such as a Henschel mixer, a Nauta mixer, or a vibrating mill, and a surface treatment is performed by dropping a drug onto the iron-containing powder. For the drug, a solution obtained by diluting the coupling agent with an alcohol solvent, a solution obtained by diluting the coupling agent with an alcohol solvent and further adding water, or a solution obtained by diluting the coupling agent with an alcohol solvent and further adding water and acid There is a solution added.
(2) Wet method The wet method is a method in which iron-containing powder is directly immersed in a chemical. The drug is a solution obtained by diluting the coupling agent with an alcohol solvent, a solution obtained by diluting the coupling agent with an alcohol solvent and further adding water, or a solution obtained by diluting the coupling agent with an alcohol solvent and further adding water and acid. There are solutions.
(3) Integral blending method In the integral blending method, when a matrix resin and an iron-containing powder are mixed, the coupling agent diluted with a stock solution or alcohol or the like is directly added to a mixer and stirred. Is the way. The method of preparing the drug is the same as the dry method and the wet method, but the amount of the coupling agent when the method is performed by the integral blend method is generally larger than that in the dry method and the wet method.

  In the dry method and the wet method, the drug is appropriately dried as necessary. When a drug using alcohol or the like is added, it is necessary to volatilize the alcohol. If the alcohol ultimately remains in the formulation, it will adversely affect the polymer content and generate gas from the product. The drying temperature is preferably higher than the boiling point of the solvent used. Further, it is preferable to use an apparatus to quickly remove the coupling agent that has not reacted with the iron-containing powder and to heat the coupling agent to a high temperature, but in consideration of the heat resistance of the coupling agent, the coupling agent is used. Is preferably maintained at a temperature lower than the decomposition point. The processing temperature is preferably about 80 to 150 ° C, and the processing time is preferably 0.5 to 4 hours. The solvent and unreacted coupling agent can be removed by appropriately selecting the drying temperature and time according to the processing amount. In the present invention, pretreatment by a dry method is preferred.

The amount of the coupling agent required to treat the surface of the iron-containing powder can be calculated by the following equation.
Amount of coupling agent (g) = Amount of iron-containing powder (g) × Specific surface area of iron-containing powder (m ² / g) / Minimum covering area of coupling agent (m ² / g)
"Minimum covering area of coupling agent" is determined by the following formula.
Minimum coating area of coupling agent (m ² /g)=(6.02×10 ²³ ) × (13 × 10 ⁻²⁰ ) / molecular weight of coupling agent In the above formula, 6.02 × 10 ²³ : Avogadro constant 13 × 10 ^-20 : Area covered by one molecule of coupling agent (0.13 nm ² )

  The required amount of the coupling agent is preferably 0.5 times or more and less than 1.0 times the amount of the coupling agent calculated by this calculation formula. The upper limit is less than 1.0 because the amount of the coupling agent actually present on the surface of the iron-containing powder is made smaller than 1.0 in consideration of unreacted components. The reason why the lower limit is set to the amount calculated by the above formula is that even a 0.5-fold amount is an amount that is sufficiently effective in improving the filling property of the iron-containing powder into the matrix resin.

  The temperature at the time of curing by the addition reaction in the present invention is preferably 25 ° C to 110 ° C. More preferably, it is 70 ° C to 100 ° C. In the above temperature range, the curing time is 5 minutes to 120 minutes, preferably 10 minutes to 30 minutes.

The raw material composition of the present invention may contain a thermally conductive filler. The thermally conductive filler includes an electrically conductive filler, an electrically insulating filler, and the like. Examples of the electrically conductive filler include carbon powder such as carbon black or metal powder. In the case of metal powders, those having a surface resistance of 1 Ω / □ or less are preferred, and specifically, metals such as gold, silver, platinum, copper, nickel, iron, palladium, cobalt, chromium, aluminum, and alloys such as stainless steel. It is preferable to use a powder of a metal or a metal powder whose surface is coated with a noble metal such as gold, silver or the like in order to reduce electric resistance. As the electrically insulating filler, alumina, zinc oxide, magnesium oxide, aluminum nitride, boron nitride, aluminum hydroxide, quartz or silica is preferable. Various shapes such as a sphere, a scale, and a polyhedron can be used. When using alumina, α-alumina having a purity of 99.5% by mass or more is preferable. The specific surface area of the thermally conductive particles is preferably in the range of 0.06 to 10 m ² / g. The specific surface area is a BET specific surface area, and the measuring method is in accordance with JIS R1626. When the average particle size is used, the range is preferably from 0.1 to 100 μm. The median diameter is measured by a laser diffraction light scattering method. As this measuring device, for example, there is a laser diffraction / scattering type particle distribution measuring device LA-950S2 manufactured by Horiba, Ltd. The silicone sheet preferably has a thermal conductivity of 0.5 W / mK or more. The preferred thermal conductivity is 0.7 W / mK or more.

When the matrix resin is an organopolysiloxane, it is preferably obtained by curing a compound having the following composition.
(A) Base polymer component: a linear organopolysiloxane having an average of two or more per molecule and alkenyl groups bonded to silicon atoms at both ends of the molecular chain; (B) crosslinking component: an average of two per molecule The organohydrogenpolysiloxane containing a hydrogen atom bonded to a silicon atom is less than 1 mole based on 1 mole of the silicon-bonded alkenyl group in the component A. (C) Platinum metal catalyst: Component A 0.01 to 1000 ppm by weight
(D) Iron-containing powder: 0.1 to 2,000 parts by weight based on 100 parts by weight of the matrix resin

(1) Base polymer component (A component)
The base polymer component (A component) is an organopolysiloxane containing two or more alkenyl groups bonded to silicon atoms in one molecule, and the organopolysiloxane containing two alkenyl groups is a silicone rubber composition of the present invention. (Base polymer component). This organopolysiloxane has two alkenyl groups having 2 to 8 carbon atoms, particularly 2 to 6 carbon atoms, such as a vinyl group and an allyl group, bonded to a silicon atom as alkenyl groups in one molecule. The viscosity at 25 ° C. is preferably from 100 to 100,000 mPa · s, particularly preferably from 100,000 to 100,000 mPa · s from the viewpoint of workability and curability.

  Specifically, an organopolysiloxane containing an alkenyl group bonded to a silicon atom at an average of two or more and in a molecular chain terminal in one molecule represented by the following general formula (Formula 1) is used. The side chains are straight-chain organopolysiloxanes blocked with triorganosiloxy groups. A viscosity at 25 ° C. of 10 to 100000 mPa · s is desirable from the viewpoint of workability and curability. The linear organopolysiloxane may contain a small amount of a branched structure (trifunctional siloxane unit) in the molecular chain.

In the formula, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having no same or different aliphatic unsaturated bonds, R ² is an alkenyl group, and k is 0 or a positive integer. Here, as the unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond of R ¹ , for example, those having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms are preferable, and specifically, , Methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, alkyl groups such as decyl, phenyl Group, tolyl group, xylyl group, aryl group such as naphthyl group, aralkyl group such as benzyl group, phenylethyl group, phenylpropyl group, and part or all of the hydrogen atoms of these groups are replaced with fluorine, bromine, chlorine, etc. Substituted with a halogen atom, a cyano group, etc., for example, a halogen atom such as a chloromethyl group, a chloropropyl group, a bromoethyl group, a trifluoropropyl group, etc. Alkyl group, cyanoethyl group and the like. As the alkenyl group for R ² , for example, those having 2 to 6 carbon atoms, particularly 2 to 3 carbon atoms are preferable, and specific examples thereof include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group and a hexenyl group. , Cyclohexenyl group and the like, and preferably a vinyl group. In the general formula (1), k is generally 0 or a positive integer satisfying 0 ≦ k ≦ 10000, preferably 5 ≦ k ≦ 2000, more preferably an integer satisfying 10 ≦ k ≦ 1200. It is.

  As the organopolysiloxane of the component A, three or more alkenyl groups bonded to a silicon atom having 2 to 8 carbon atoms, particularly 2 to 6 carbon atoms, such as a vinyl group and an allyl group, usually 3 to 30 Preferably, an organopolysiloxane having about 3 to about 20 may be used in combination. The molecular structure may be any of linear, cyclic, branched, and three-dimensional network. Preferably, the main chain is composed of repeating diorganosiloxane units, and both ends of the molecular chain are blocked with triorganosiloxy groups, and the viscosity at 25 ° C. is 100 to 100,000 mPas, particularly 100 to 100,000 mPas. Organopolysiloxane.

  The alkenyl group may be attached to any part of the molecule. For example, it may include those bonded to the silicon atom at the terminal of the molecular chain or at the non-terminal (in the middle of the molecular chain) of the molecular chain. Above all, it has 1 to 3 alkenyl groups on both silicon atoms at both ends of the molecular chain represented by the following general formula (Formula 2) (provided that the alkenyl group bonded to the silicon atom at the molecular chain end is When the total is less than 3 at both ends, the alkenyl group bonded to the silicon atom at the non-terminal (in the middle of the molecular chain) of the silicon atom (for example, as a substituent in a diorganosiloxane unit) has at least one alkenyl group. As described above, a chain organopolysiloxane having a viscosity of 10 to 1,000,000 mPa · s at 25 ° C. is desirable from the viewpoints of workability, curability, etc. The linear organopolysiloxane has a small amount of branched It may contain a tertiary structure (trifunctional siloxane unit) in the molecular chain.

In the formula, R ³ is the same or different, unsubstituted or substituted monovalent hydrocarbon group, and at least one is an alkenyl group. R ⁴ is an unsubstituted or substituted monovalent hydrocarbon group having no same or different aliphatic unsaturated bond, R ⁵ is an alkenyl group, and l and m are 0 or a positive integer. Here, as the monovalent hydrocarbon group for R ³ , those having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms are preferable, and specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, Alkyl groups such as isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group, phenyl group, tolyl group, xylyl group, naphthyl group, etc., benzyl Alkenyl groups such as aralkyl groups such as phenylethyl group and phenylpropyl group, vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group and octenyl group, and hydrogen of these groups. Those in which some or all of the atoms have been replaced with halogen atoms such as fluorine, bromine and chlorine, cyano groups, etc., for example, chloromethyl , Chloropropyl group, bromoethyl group, and a halogen-substituted alkyl group or cyanoethyl group such trifluoropropyl group.

The monovalent hydrocarbon group of R ⁴ also preferably has 1 to 10 carbon atoms, and particularly preferably has 1 to 6 carbon atoms, and the same as the specific examples of the above R ¹ can be exemplified, provided that the alkenyl group is not included. . As the alkenyl group for R ⁵ , for example, those having 2 to 6 carbon atoms, particularly 2 to 3 carbon atoms are preferable, and specific examples are the same as R ^{2 in the} above formula (Chemical Formula 1). It is.

  l and m are generally 0 or a positive integer satisfying 0 <l + m ≦ 10000, preferably 5 ≦ l + m ≦ 2000, more preferably 10 ≦ l + m ≦ 1200, and 0 <l / (l + m ) ≦ 0.2, preferably an integer satisfying 0.0011 ≦ l / (l + m) ≦ 0.1.

(2) Crosslinking component (B component)
The organohydrogenpolysiloxane of the component B of the present invention acts as a crosslinking agent, and forms a cured product by an addition reaction (hydrosilylation) between the SiH group in the component and the alkenyl group in the component A. Things. Such an organohydrogenpolysiloxane may be any one having at least two hydrogen atoms bonded to a silicon atom (ie, SiH group) in one molecule, and the molecular structure of the organohydrogenpolysiloxane is as follows. May be any of linear, cyclic, branched, and three-dimensional network structures, but the number of silicon atoms in one molecule (that is, the degree of polymerization) is from 2 to 1,000, particularly from about 2 to 300. Can be used.

The position of the silicon atom to which the hydrogen atom is bonded is not particularly limited, and may be at the terminal of the molecular chain or at a non-terminal (midway). Examples of the organic group bonded to a silicon atom other than a hydrogen atom include an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond similar to R ^{1 in the} general formula (Chemical Formula 1). .

  As the organohydrogenpolysiloxane of the component B, those having the following structures can be exemplified.

  In the above formula, Ph is an organic group containing at least one of a phenyl group, an epoxy group, an acryloyl group, a methacryloyl group, and an alkoxy group. L is an integer of 0 to 1,000, particularly an integer of 0 to 300, and M is an integer of 1 to 200. )

(3) Catalyst component (C component)
The catalyst component C is a component that promotes curing of the present composition. As the component C, a known catalyst used for the hydrosilylation reaction can be used. For example, platinum black, secondary platinum chloride, chloroplatinic acid, a reaction product of chloroplatinic acid with a monohydric alcohol, a complex of chloroplatinic acid with olefins or vinyl siloxane, a platinum-based catalyst such as platinum bisacetoacetate, a palladium-based catalyst Examples of the catalyst include a platinum group metal catalyst such as a catalyst and a rhodium catalyst. The compounding amount of the component C may be an amount necessary for curing, and can be appropriately adjusted according to a desired curing speed and the like. 0.01 to 1000 ppm as a metal atom weight is added to the component A.

(4) Iron-containing powder (D component)
The iron-containing powder is isopropyl triisostearoyl titanate, at least one titanium-based coupling agent selected from diisostearoyl ethylene titanate and partial hydrolysates thereof, alkyl acetoacetate aluminum diisopropylate and partial hydrolysates thereof At least one aluminum-based coupling agent selected from the group consisting of R (CH ₃ ) _a Si (OR ′) _3-a (R is an alkyl group having 1 to 20 carbon atoms, R ′ is an alkyl group having 1 to 4 carbon atoms, a is surface-treated with at least one selected from silane coupling agents represented by 0 or 1) and partial hydrolysis products thereof. The surface treatment may be performed in advance, or a surface treatment agent may be added during mixing. This surface treatment can prevent curing inhibition.

Hereinafter, an embodiment will be described. The present invention is not limited to the embodiments.
(Example 1)
<Raw materials>
(1) Silicone polymer A liquid: Silicone polymer containing vinyl group + Pt-based catalyst B liquid: Silicone polymer containing vinyl group + Silicone polymer containing SiH (2) Filler triiron tetroxide (Fe ₃ O ₄ ): Black pigment (3) ) Filler surface treatment agent Aluminate treatment agent, alkyl acetoacetate aluminum diisopropylate (4) Filler surface treatment Pre-treatment by dry method. Specifically, 2 g of the aluminate treating agent was added to 100 g of the triiron tetroxide (Fe ₃ O ₄ ), and the mixture was stirred and then heated at 70 ° C. for 1 hour.
(5) Preparation of master batch To 70 g of the filler after the surface treatment, 30 g of the silicone polymer A liquid was added and stirred.
(6) Formation of Molded and Cured Product 30 g of the silicone polymer B solution was added to 100 g of the master batch of the solution A, and the mixture was stirred to form a sheet having a thickness of 1.0 mm. This sheet was heated at a temperature of 100 ° C. for 15 minutes to cure the sheet. The curability was evaluated on the first day when the master batch was prepared and one week after the master batch was prepared. The results are summarized in Table 1 below.

(Example 2)
An experiment was performed in the same manner as in Example 1 except that the aluminate treatment agent was used instead of the filler surface treatment agent, and a titanate treatment agent and isopropyl triisostearoyl titanate were used.

(Example 3)
Instead of the pretreatment method by the dry method, treatment was performed by an integral blend method. That is, 1.4 g of the titanate treating agent was added to 30 g of the silicone polymer A liquid and stirred. This was used as a master batch. The molding and the cured product were tested in the same manner as in Example 2.

(Comparative Example 1)
An experiment was performed in the same manner as in Example 1 except that the surface treatment of the filler was not performed. The results are summarized in Table 1. In Table 1, curability evaluation: A indicates good curability, and B indicates uncured.

As is clear from Table 1, in each of the examples of the present invention, curing inhibition did not occur even when the master batch was stored for one week, and the storage stability was high. On the other hand, Comparative Example 1, which was not surface-treated, caused curing inhibition from the first day.
Also, comparing the pre-treatment of Examples 1 and 2 with the integral blend of Example 3, the pre-treated masterbatch had a clearly lower viscosity. Although the viscosity was too high to be measured, it was checked by hand stirring. On the other hand, the integral blend of Example 3 had a high viscosity at first, but the viscosity decreased after stirring to some extent, and showed dilatancy. From this, the pre-processing was superior.

Claims (8)

An addition-curable raw material composition comprising a polymer, a curing catalyst, and an iron-containing powder,
The iron-containing powder is iron, iron oxide, at least one selected from metal oxides containing iron,
An addition-curable raw material composition, wherein the iron-containing powder is surface-treated with at least one coupling agent selected from a titanium-based coupling agent, an aluminum-based coupling agent, and a silane-based coupling agent.   The addition-curable raw material composition according to claim 1, wherein the addition-curable raw material composition is a raw material composition for a masterbatch for obtaining a molded article.   The addition-curable raw material composition according to claim 1, wherein the polymer is an organopolysiloxane.   The addition-curable raw material composition according to any one of claims 1 to 3, wherein the titanium-based coupling agent is at least one selected from isopropyltriisostearoyl titanate, diisostearoylethylene titanate, and a partial hydrolyzate thereof. object.   The addition-curable raw material composition according to any one of claims 1 to 4, wherein the aluminum-based coupling agent is at least one selected from alkyl acetoacetate aluminum diisopropylate and a partial hydrolyzate thereof. The silane coupling agent may be R (CH ₃ ) _a Si (OR ′) _3-a (R is an alkyl group having 1 to 20 carbon atoms, R ′ is an alkyl group having 1 to 4 carbon atoms, a is 0 or The addition-curable raw material composition according to any one of claims 1 to 4, which is at least one selected from the silane compounds represented by 1) and partial hydrolysates thereof. The iron oxide, addition curable raw material composition according to claim 1 is at least one selected from triiron tetraoxide (Fe ₃ O ₄₎ and ferric oxide (Fe ₂ O ₃₎ object.   The addition-curable raw material composition according to any one of claims 1 to 7, wherein the coupling agent is added in an amount of 0.1 to 10 parts by mass based on 100 parts by mass of the iron-containing powder.