JP2011127063A - Epoxy resin curing agent and epoxy resin composition including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin curing agent providing an epoxy resin with a high glass transition temperature even when silica particles are included, and an epoxy resin composition including the same. <P>SOLUTION: Surface-treated silica particles are obtained by a reaction of a compound having an ester skeleton including an alkoxysilane terminal and specific dicyclopentadiene with colloidal silica particles. The epoxy resin curing agent includes the silica particles. The epoxy resin composition includes the epoxy resin curing agent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an epoxy resin curing agent, and relates to an epoxy resin curing agent using colloidal silica particles surface-treated with a silane coupling agent having a specific structure.

Conventionally, curable resins such as epoxy resins have been widely used in fields such as molding materials, laminate and adhesive materials, various electronic and electrical parts, and coating materials. In particular, in the field of sealing technology for electronic component elements such as transistors and ICs, epoxy resins are excellent in properties such as moldability, electrical properties, moisture resistance, heat resistance, mechanical properties, etc. Epoxy resin compositions are widely used.
In such a conventional composition, silica particles such as colloidal silica coexist in order to improve hardness, and a curing agent and an epoxy resin are included. However, when silica particles are allowed to coexist, the hardness of the resulting epoxy resin is improved, but the glass transition temperature (Tg) is lowered, which is a problem.

Moreover, as an epoxy resin hardening | curing agent which has a chemical bond with a silane compound, the following is known, for example.

Patent Document 1 discloses a polysiloxane compound having a phenolic hydroxyl group and a method for producing the same. The polysiloxane compound is obtained by hydrolysis reaction of a silane compound having a specific structure having a phenolic hydroxyl group and a compound having a trisubstituted silyl group, and has a use as an epoxy resin curing agent. There is a description that the obtained epoxy resin can be used as a wide variety of organic-inorganic hybrid materials.

In Patent Document 2, there is a description of a compound obtained by a reaction between a phenol compound having two or more phenolic hydroxyl groups in the molecule and a silane compound having two functional groups capable of reacting with the phenolic hydroxyl group. It is described that it is useful as an epoxy resin curing agent that can exhibit curability, heat resistance, and low water absorption.

Patent Document 3 describes an epoxy resin curing agent composed of a phenoxysilane compound having two or more siloxy groups such as p-bis (trimethylsiloxy) benzene, and a composition of this and an epoxy resin.
However, many conventional curing agents having a silyl bond can be obtained by reaction with a phenolic hydroxyl group, and the curing agent improves the water absorption problem but tends to lower the glass transition temperature. .

JP 2008-266576 A JP 2006-257400 A JP 2004-307655 A

An object of the present invention is to provide an epoxy resin curing agent having a high glass transition temperature even if it contains colloidal silica particles for improving hardness, and an epoxy resin composition containing the same.

In the present invention, in view of the prior art, surface-treated silica particles obtained by a reaction between the compound represented by the general formula (1) and colloidal silica particles,

Wherein A is an alkyl group having 1 to 6 carbon atoms, X is O, NH or S, n is an integer of 1 to 6, and -Y is a general formula (2), (3), (4) and (5 ) Represents a group selected from the group consisting of:

（一般式（２）〜（５）の式中、Ｂは炭素数１〜６のアルキル基、ｍは１〜６の整数、Ｐ、Ｑ、Ｒ、Ｔ及びＵは各々炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、ニトロ基又はハロゲン原子を表す。ｐ、ｒは０〜５の整数、ｑ、ｔは０〜４の整数、ｕは０〜３の整数を表す。Ｐ、Ｑ、Ｒ、Ｔ及びＵで表される置換基は、それぞれ、同一であっても異なっていてもよい。−Ｚ−は−Ｏ−、−ＣＯ−、−ＣＨ_２−、−Ｃ（ＣＨ_３）_２−又は−ＳＯ_２−を表す。）]
該シリカ粒子を含むエポキシ樹脂硬化剤、及び該エポキシ樹脂硬化剤を含むエポキシ樹脂組成物を提供することにより上記課題を解決する。

(In the formulas of the general formulas (2) to (5), B is an alkyl group having 1 to 6 carbon atoms, m is an integer of 1 to 6, and P, Q, R, T, and U are each 1 to 4 carbon atoms. An alkyl group, an alkoxy group having 1 to 4 carbon atoms, a nitro group, or a halogen atom, p and r are integers of 0 to 5, q and t are integers of 0 to 4, and u is an integer of 0 to 3. The substituents represented by P, Q, R, T, and U may be the same or different, and —Z— represents —O—, —CO—, —CH ₂ —, —C ( CH ₃ ) ₂ — or —SO ₂ — is represented.)]
The above problems are solved by providing an epoxy resin curing agent containing the silica particles and an epoxy resin composition containing the epoxy resin curing agent.

  According to the present invention, it is possible to provide an epoxy resin curing agent having a high hardness and a high glass transition temperature, and an epoxy resin composition containing the same.

It is a ²⁹ Si-NMR chart of colloidal silica particles before surface treatment. 3 is a ²⁹ Si-NMR chart of surface-treated silica particles obtained in Example 1. FIG.

That is, the present invention
1. Surface-treated silica particles obtained by reaction of the compound represented by the general formula (1) with colloidal silica particles,

Wherein A is an alkyl group having 1 to 6 carbon atoms, X is O, NH or S, n is an integer of 1 to 6, and -Y is a general formula (2), (3), (4) and (5 ) Represents a group selected from the group consisting of:

（一般式（２）〜（５）の式中、Ｂは炭素数１〜６のアルキル基、ｍは１〜６の整数、Ｐ、Ｑ、Ｒ、Ｔ及びＵは各々炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、ニトロ基又はハロゲン原子を表す。ｐ、ｒは０〜５の整数、ｑ、ｔは０〜４の整数、ｕは０〜３の整数を表す。Ｐ、Ｑ、Ｒ、Ｔ及びＵで表される置換基は、それぞれ、同一であっても異なっていてもよい。−Ｚ−は−Ｏ−、−ＣＯ−、−ＣＨ_２−、−Ｃ（ＣＨ_３）_２−又は−ＳＯ_２−を表す。）]
２．一般式（１）におけるＸが、ＮＨである１．に記載の表面処理されたシリカ粒子、
３．一般式（１）及び（２）におけるＡ及びＢが、共にエチル基である１．又は２．に記載の表面処理されたシリカ粒子、
４．一般式（１）におけるｎが、２又は３の整数である１．〜３．の何れかに記載の表面処理されたシリカ粒子、
５．一般式（２）におけるｍが、２又は３の整数である１．〜４．の何れかに記載の表面処理されたシリカ粒子、
６．１．〜５．の何れかに記載の表面処理されたシリカ粒子を含むエポキシ樹脂硬化剤、
７．６．に記載のエポキシ樹脂硬化剤を含むエポキシ樹脂組成物、
に関する。

(In the formulas of the general formulas (2) to (5), B is an alkyl group having 1 to 6 carbon atoms, m is an integer of 1 to 6, and P, Q, R, T, and U are each 1 to 4 carbon atoms. An alkyl group, an alkoxy group having 1 to 4 carbon atoms, a nitro group, or a halogen atom, p and r are integers of 0 to 5, q and t are integers of 0 to 4, and u is an integer of 0 to 3. The substituents represented by P, Q, R, T, and U may be the same or different, and —Z— represents —O—, —CO—, —CH ₂ —, —C ( CH ₃ ) ₂ — or —SO ₂ — is represented.)]
2. 1. X in the general formula (1) is NH Surface-treated silica particles according to
3. 1. In formulas (1) and (2), A and B are both ethyl groups. Or 2. Surface-treated silica particles according to
4). 1. n in the general formula (1) is an integer of 2 or 3. ~ 3. The surface-treated silica particles according to any one of
5. 1. m in the general formula (2) is an integer of 2 or 3. ~ 4. The surface-treated silica particles according to any one of
6.1. ~ 5. An epoxy resin curing agent comprising the surface-treated silica particles according to any one of
7.6. An epoxy resin composition comprising the epoxy resin curing agent according to claim 1,
About.

General formula (1)

In the formula of the compound represented by A, A is an alkyl group having 1 to 6 carbon atoms. As such an alkyl group, a lower alkyl group is preferable from the viewpoint of reactivity with colloidal silica particles, and a methyl group or an ethyl group is particularly preferable.
X is O, NH, or S, and -XC = O represents an ester group, an amide group, or a thioester group, respectively, and an amide group is particularly preferable from the viewpoint of excellent stability.

-Y represents a group selected from the group consisting of general formulas (2), (3), (4) and (5).

（一般式（２）〜（５）の式中、Ｂは炭素数１〜６のアルキル基、ｍは１〜６の整数、Ｐ、Ｑ、Ｒ、Ｔ及びＵは各々炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、ニトロ基又はハロゲン原子を表す。ｐ、ｒは０〜５の整数、ｑ、ｔは０〜４の整数、ｕは０〜３の整数を表す。Ｐ、Ｑ、Ｒ、Ｔ及びＵで表される置換基は、それぞれ、同一であっても異なっていてもよい。−Ｚ−は−Ｏ−、−ＣＯ−、−ＣＨ_２−、−Ｃ（ＣＨ_３）_２−又は−ＳＯ_２−を表す。）]

(In the formulas of the general formulas (2) to (5), B is an alkyl group having 1 to 6 carbon atoms, m is an integer of 1 to 6, and P, Q, R, T, and U are each 1 to 4 carbon atoms. An alkyl group, an alkoxy group having 1 to 4 carbon atoms, a nitro group, or a halogen atom, p and r are integers of 0 to 5, q and t are integers of 0 to 4, and u is an integer of 0 to 3. The substituents represented by P, Q, R, T, and U may be the same or different, and —Z— represents —O—, —CO—, —CH ₂ —, —C ( CH ₃ ) ₂ — or —SO ₂ — is represented.)]

Specifically, the group represented by the general formulas (3) to (5) is preferably a residue of an aromatic monohydroxy compound. Examples of the aromatic monohydroxy compound include phenol, o-cresol, m-cresol, p-cresol, 3,5-xylenol, o-phenylphenol, p-phenylphenol, 2-benzylphenol, 4-benzylphenol, 4- (α-cumyl) phenol, α-naphthol, β-naphthol And aromatic monohydroxy compounds.
Moreover, group which is General formula (2) can also be used. In this case, a group in which B is an ethyl group and m is 2 to 3 is preferable.

Next, an example of a method for producing a compound having a group represented by the general formula (2) among the compounds represented by the general formula (1) is represented by the following formula (6).

The phenolized dicyclopentadiene compound represented by the formula (A) is reacted with isophthalic acid chloride (first step), and then the formula (7)

(2nd process), it is set as the compound represented by Formula (C).
Then, it can be set as the target surface-treated silica particle by making it react with the compound represented by Formula (C), and the colloidal silica disperse | distributed in the organic solvent (3rd process).

In the first step, it is preferable to add a basic substance in order to capture hydrogen chloride produced by the reaction. Although there is no restriction | limiting in such a basic substance, The basic substance which is an organic amine substance is preferable, and a triethylamine, a pyridine, etc. can be mentioned.
The reaction is preferably performed in the presence of an organic solvent, and is not particularly limited as long as it is not an organic solvent that affects the reaction. Examples thereof include ether solvents and ketone solvents, and more specifically. May include diethyl ether, diisopropyl ether, tetrahydrofuran, acetone, methyl ethyl ketone, and the like.
The reaction temperature varies depending on the basic substance and organic solvent to be used, and examples thereof include a temperature of 0 to 100 ° C.
Although reaction time changes with basic substances to be used, an organic solvent, and reaction temperature, it can mention 0.5 to 10 hours.

In the second step, an amidation reaction between the compound (B) obtained in the first step and aminoalkoxysilane is performed.
The reaction is preferably performed in the presence of an organic solvent, and is not particularly limited as long as it is not an organic solvent that affects the reaction. Examples thereof include ether solvents and ketone solvents, and more specifically. May include diethyl ether, diisopropyl ether, tetrahydrofuran, acetone, methyl ethyl ketone, and the like.
The reaction temperature varies depending on the basic substance and organic solvent to be used, and examples thereof include a temperature of 0 to 100 ° C.
Although reaction time changes with basic substances to be used, an organic solvent, and reaction temperature, it can mention 0.5 to 10 hours.

The reaction between the compound (C) and the colloidal silica colloidal silica particles dispersed in the organic solvent in the third step is performed by reacting the trialkoxy moiety of the compound represented by the formula (C) with the surface of the colloidal silica particles. There is no particular limitation as long as a bond is formed.

In the reaction, a compound that promotes the reaction may not be added, but the reaction is promoted by the presence of an acid or an alkali. For example, inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, sulfuric acid, carboxylic acids such as formic acid, acetic acid, propionic acid, succinic acid, lithium hydroxide, sodium hydroxide, potassium hydroxide, water Hydroxides such as rubidium oxide, cesium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetraisobutylammonium hydroxide, choline, titanium Examples thereof include carboxylates and alkoxides of Group 1 to 14 elements such as tetraisopropoxide, iron bisoctylate, zinc acetate, aluminum triisopropoxide, and dibutyltin dilaurate.

In this reaction, a solvent can be used as necessary. For example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, chloroform, tetrahydrofuran and the like can be used. The amount of these solvents used varies depending on the solubility in the raw materials used, and can be appropriately selected and used.

The reaction temperature varies depending on the solvent and catalyst type to be used, but is usually in the range of 0 to 200 ° C, preferably in the range of 25 to 80 ° C.

Similarly, it can manufacture also about the compound which has group represented by General formula (3)-(5).
For example, among the compounds represented by the general formula (5), those having an α-naphthol group are reacted with α-naphthol and the compound represented by the formula (B) after the first step. And an aminopropyltriethoxysilane compound represented by the formula (7). In that case, after reacting the aminopropyltriethoxysilane compound represented by the formula (7) with the compound represented by the formula (B), it may be reacted with α-naphthol.
Thus, when α-naphthol is used, a compound represented by the following general formula (D) can be obtained.

One silicon atom contained in the raw material colloidal silica particles can form a maximum of four siloxane bonds. ^{In 29} Si-NMR, when the siloxane bond per silicon atom is 0, it is observed as the signal of the chemical shift of the lowest magnetic field, and the chemical shift sequentially shifts to the high magnetic field as the siloxane bond increases. A signal derived from the number n of siloxane bonds is assigned as Qn, and is represented by Q _{0 to} Q _{4 in} correspondence with the number of siloxane bonds 0 to ₄ .

FIG. 1 is a ²⁹ Si-NMR chart of colloidal silica particles before the reaction, and peaks corresponding to Q ₃ and Q ₄ are confirmed. Peak corresponding to Q ₃ are a peak derived from a silicon atom having three siloxane bonds and one silanol bonds present in the colloidal silica particles,
Peak corresponding to Q ₄ are, a peak derived from the silicon atom having four siloxane bonds present in the colloidal silica particles.

FIG. 2 is a ²⁹ Si-NMR chart of the surface-treated silica particles obtained by the reaction of the compound represented by the general formula (1) of the present invention and colloidal silica particles, and Q ₃ and Q _{4 in} FIG. Since the ratio of the peak corresponding to (Q ₄ / Q ₃ ) is large, it is clear that the ratio of silicon atoms having four siloxane bonds present in the colloidal silica particles is increased. It can be confirmed that the colloidal silica particles are surface-treated with a compound represented by the general formula (1) via a siloxane bond.

Examples of the epoxy resin that can be used together with the surface-treated silica particles obtained by reacting the compound represented by the general formula (1) of the present invention with colloidal silica particles include, for example, bisphenol F type epoxy resins and bisphenol A types. Glycidyl ether type epoxy such as epoxy resin, cresol novolak type epoxy resin, phenol novolak type epoxy resin, biphenyl type epoxy resin, phenol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, dihydroxynaphthalene type epoxy resin Examples thereof include an epoxy resin having two or more epoxy groups in the molecule, such as a resin, a glycidyl ester type epoxy resin, a glycidyl amine type epoxy resin, and a halogen type epoxy resin. These epoxy resins may be used alone or in combination of two or more.

In curing the epoxy resin, it is desirable to use a curing accelerator in combination. As such a curing accelerator, a known curing accelerator for curing an epoxy resin can be used. For example, a tertiary amine, a quaternary ammonium salt, an imidazole, an organic phosphine compound, a quaternary phosphonium salt, and the like. Can be mentioned. More specifically, tertiary amines such as triethylamine, triethylenediamine, benzyldimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo (5,4,0) undecene-7, etc. Imidazoles such as imidazole, 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, triphenylphosphine, tributylphosphine, Examples thereof include organic phosphine compounds such as (p-methylphenyl) phosphine and tri (nonylphenyl) phosphine, and phosphonium compounds such as tetraphenylphosphonium tetraphenylborate and tetraphenylphosphonium salts of bisphenols. .

The amount used varies depending on the type, but it is preferably used in the range of 0.1 to 5 parts by mass with respect to 100 parts by mass of the epoxy resin.

In addition to the epoxy resin curing agent of the present invention, if necessary, other types of curing agents, fillers, coupling agents, mold release agents, colorants, flame retardants, flame retardant aids, low stress agents, etc. It can also be added or reacted in advance.

Thus, the surface-treated silica particles of the present invention are mixed with the above compounding agent including an epoxy resin by a mixer or the like, and are subjected to general techniques such as kneading with a hot roll or a kneader and pulverization to obtain a molding material. Curing of the epoxy resin composition can be performed, for example, in a temperature range of 100 to 250 ° C., and a molded body having an organic-inorganic hybrid structure can be obtained.

Hereinafter, the present invention will be described in more detail with reference to examples.

(Example 1) First step for producing a compound represented by the general formula (C):
To a solution of 10.1 g (50 mmol) of isophthalic acid chloride in 100 mL of methyl ethyl ketone was added 5.56 g (55 mmol) of triethylamine, and 30 mL of a solution of 8.4 g (26.2 mmol) of phenolized dicyclopentadiene (A) in 100 mL of methyl ethyl ketone was added. It was dripped below. The reaction vessel was further stirred at 30 ° C. or lower for 3 hours.
Second step:
Further, 5.56 g (55 mmol) of triethylamine was added to the reaction solution, and a solution of 14.3 g (82.5 mmol) of aminopropyltriethoxysilane ((EtO) ₃ SiC ₃ H ₆ NH ₂ ) in 56 mL of methyl ethyl ketone was added dropwise over 15 minutes. did. The reaction vessel was further stirred at 30 ° C. or lower for 3 hours, and then the reaction solution was quickly filtered to remove triethylamine hydrochloride formed in the system. The recovered amount of the solution was 232 g.
Third step:
Of the solution obtained in the second step, half of 116 g was used in the third step. A solution obtained by diluting 166 g of colloidal silica (MEK-ST, silica content 30 wt%, manufactured by Nissan Chemical Co., Ltd.) dispersed in methyl ethyl ketone with 333 g of methyl ethyl ketone, and stirring the solution, was obtained in the second step. Was reacted dropwise. The dropping was performed over 30 minutes. After completion of the dropwise addition, the temperature in the container was raised to 80 ° C. and reacted for 5 hours.
Purification process:
The reaction solution obtained in the third step was centrifuged at 9000 rpm for 20 minutes at 5 ° C. The obtained precipitate was recovered and centrifuged again in methyl ethyl ketone at 9000 rpm for 20 minutes at 5 ° C. This operation was performed twice, and the resulting precipitate was collected and dried to obtain 33.5 g of the desired product (C).

(Example 2) Preparation of compound represented by general formula (D) After the first step described in Example 1, 14.3 g of aminopropyltriethoxysilane ((EtO) ₃ SiC ₃ H ₆ NH ₂ ) ( In place of 82.5 mmol), α-naphthol 3.6 g (25 mmol) and aminopropyltriethoxysilane ((EtO) ₃ SiC ₃ H ₆ NH ₂ ) 7.2 g (41.2 mmol) were added. In the same manner as in Example 1, 14.8 g of the target product (D) was obtained.

(Example 3) Preparation of solution using surface-treated silica particles 2 g of active ester curing agent (E) was dissolved in 8 g of toluene. To the obtained solution, 1.67 g of a bisphenol A type epoxy resin (product name: EP-850 (manufactured by DIC), epoxy equivalent: 189) and 0.372 g of 4-dimethylaminopyridine 1% toluene solution were added.
Furthermore, 0.447 g of the silica particles obtained in Example 1 was added, and the mixture was stirred for 30 minutes so that the silica particles were dispersed to obtain an evaluation test solution.

(Comparative Example 1)
Instead of the silica particles used in Example 3, 1 g of colloidal silica (TOL-ST (manufactured by Nissan Chemical Industries), silica content is 41% by mass) dispersed in toluene was used in the same manner as in Example 3. An evaluation test solution was prepared.

(Evaluation Test Example) Solid Viscoelasticity Test This test was performed using the evaluation test liquids obtained in Example 3 and Comparative Example 1, and the viscoelasticity of each test liquid was evaluated.
1. Sample Preparation 1) The liquid for evaluation test obtained in Example 3 and Comparative Example 1 was heated on a hot plate for 30 minutes (60 ° C.) to volatilize the solvent.
2) Using an applicator (for 50 μm), the liquid obtained in 1) was applied to a glass plate on which a PET film coated with a release agent was stretched.
3) The glass plate was heated (60 ° C.) for 3 minutes on a hot plate.
4) The glass plate was heated at 80 ° C. for 30 minutes, 120 ° C. for 1 hour, and 140 ° C. for 1 hour.
5) The sample was peeled off from the PET film and sandwiched between glass plates from both sides. Then, it was heated at 160 ° C. for 2 hours and at 180 ° C. for 2 hours.
2. Evaluation of viscoelasticity In order to evaluate the viscoelasticity of the sample obtained in step 1, the glass transition temperature (Tg) was measured. Table 1 shows the results.

The silica particles surface-treated with the silane coupling agent of the present invention can be used as a curing agent for epoxy resins.

Q3: A peak derived from a silicon atom having three siloxane bonds and one silanol bond present in colloidal silica particles.
Q4: A peak derived from a silicon atom having four siloxane bonds present in a surface-treated silica particle obtained by a reaction between a compound represented by the general formula (1) and colloidal silica particles.

Claims (7)

Surface-treated silica particles obtained by a reaction between a compound represented by the general formula (1) and colloidal silica particles.

Wherein A is an alkyl group having 1 to 6 carbon atoms, X is O, NH or S, n is an integer of 1 to 6, and -Y is a general formula (2), (3), (4) and (5 ) Represents a group selected from the group consisting of:

(In the formulas of the general formulas (2) to (5), B is an alkyl group having 1 to 6 carbon atoms, m is an integer of 1 to 6, and P, Q, R, T, and U are each 1 to 4 carbon atoms. An alkyl group, an alkoxy group having 1 to 4 carbon atoms, a nitro group, or a halogen atom, p and r are integers of 0 to 5, q and t are integers of 0 to 4, and u is an integer of 0 to 3. The substituents represented by P, Q, R, T, and U may be the same or different, and —Z— represents —O—, —CO—, —CH ₂ —, —C ( CH ₃ ) ₂ — or —SO ₂ — is represented.)] The surface-treated silica particles according to claim 1, wherein X in the general formula (1) is NH. The surface-treated silica particles according to claim 1 or 2, wherein A and B in the general formulas (1) and (2) are both ethyl groups. The surface-treated silica particles according to any one of claims 1 to 3, wherein n in the general formula (1) is an integer of 2 or 3. The surface-treated silica particles according to any one of claims 1 to 4, wherein m in the general formula (2) is an integer of 2 or 3. The epoxy resin hardening | curing agent containing the surface-treated silica particle in any one of Claims 1-5. An epoxy resin composition comprising the epoxy resin curing agent according to claim 6.

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