JP7126999B2 - Alkynyl group-containing cyclic organopolysiloxane and hydrosilylation reaction control agent - Google Patents

Description

The present invention relates to novel alkynyl group-containing organopolysiloxanes useful as hydrosilylation reaction control agents.

Platinum-catalyzed addition reactions between aliphatic unsaturated bonds and hydrosilyl groups are applied in many fields, and in the field of silicone industry in particular, it is widely used as a means of cross-linking addition reaction type resins and rubbers.

Since the reaction proceeds even at room temperature in addition reaction-type silicone resin compositions that apply such hydrosilylation reactions, reaction inhibitors are generally added for the purpose of adjusting the curing speed and improving storage stability. Examples of reaction controllers include 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, 2,5-dimethyl-3-hexyne-2,5-diol, 3-methyl-1- Acetylene alcohols such as pentadecyn-3-ol (Patent Document 1) are used.

However, since the above acetylene alcohols are composed only of a hydrocarbon skeleton, there is a problem that when they are added to a resin composition as a hydrosilylation control agent, the resin is colored in a reliability test after curing.

（式中、複数のＲ^１は、同一でも異なってもよく、水素原子、炭素原子数１～１０の置換もしくは非置換の脂肪族１価炭化水素基またはアセチレン性不飽和基を有するアルコキシ基であって、Ｒ^１の少なくとも１つはアセチレン性不飽和基を有するアルコキシ基であり；ｎは０～５の整数である。）
で示されるアセチレン性不飽和基を有するアルコキシ基で変性されたオルガノシロキサンを反応制御剤として用いることが記載されている。 As a countermeasure against this, for example, in Patent Document 2, the following formula,

(Wherein, the plurality of R ¹ may be the same or different, and is a hydrogen atom, a substituted or unsubstituted aliphatic monovalent hydrocarbon group having 1 to 10 carbon atoms, or an alkoxy group having an acetylenically unsaturated group. wherein at least one of R ¹ is an alkoxy group having an acetylenically unsaturated group; n is an integer from 0 to 5.)
It is described that an organosiloxane modified with an alkoxy group having an acetylenically unsaturated group represented by is used as a reaction control agent.

Japanese Patent Publication No. 2014-523938 JP-A-64-51466

However, in the straight-chain organosiloxane described in Patent Document 2, it is difficult to place the acetylene groups adjacent to each other, and a sufficient reaction suppressing effect may not be obtained. In addition, for applications that require transparency in the cured product, development of a reaction control agent that has sufficient reaction control ability before curing and can suppress coloring of the cured product after curing is being developed. was wanted.

The present invention has been made in view of the above problems, and provides a composition that can function as a hydrosilylation reaction inhibitor in an addition-curable organopolysiloxane resin composition and has excellent discoloration resistance after curing. An object of the present invention is to provide an alkynyl group-containing organopolysiloxane.

In order to achieve the above objects, the present invention was investigated, and found that a cyclic organopolysiloxane having at least one alkynyl group represented by the following formula (1) was synthesized and that the organopolysiloxane could solve the above objects. This discovery led to the present invention.

（式中、Ｒ^１は互いに独立に、炭素数１～６の飽和脂肪族炭化水素基、または炭素数６～１２の芳香族炭化水素基から選ばれる基であり、Ｒ^２は互いに独立に、水素原子又は下記式（Ａ）で表される基であり、ただし、Ｒ^２のうち少なくとも１つは式（Ａ）で表される基であり、ｎは３～６の整数である）

（式中、Ｒ^３は互いに独立に、水素原子又は炭素数１～６の飽和脂肪族炭化水素基であり、ａは０～６の整数である）。
That is, the present invention provides a hydrosilylation reaction controller comprising an alkynyl group-containing cyclic organopolysiloxane represented by the following formula (1).

(wherein R ¹ is a group independently selected from a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ² is each independently a hydrogen atom or a group represented by the following formula (A), provided that at least one of R ² is a group represented by the formula (A), and n is an integer of 3 to 6)

(wherein R ³ are each independently a hydrogen atom or a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, and a is an integer of 0 to 6).

The addition reaction-curable silicone composition containing the alkynyl group-containing cyclic organopolysiloxane of the present invention as a hydrosilylation reaction inhibitor can give a cured product with excellent discoloration resistance in reliability tests such as heat and moisture resistance tests. Furthermore, it is also possible to provide a composition having excellent storage stability at room temperature.

1 is a ¹ H-NMR spectrum chart of the compound synthesized in Example 1. FIG. 2 is a ¹ H-NMR spectrum chart of the compound synthesized in Example 2. FIG.

（式中、Ｒ^１は互いに独立に、炭素数１～６の飽和脂肪族炭化水素基、または炭素数６～１２の芳香族炭化水素基から選ばれる基であり、Ｒ^２は互いに独立に、水素原子又は下記式（Ａ）で表される基であり、ただし、Ｒ^２のうち少なくとも１つは式（Ａ）で表される基であり、ｎは３～６の整数である）

（式中、Ｒ^３は互いに独立に、水素原子又は炭素数１～６の飽和脂肪族炭化水素基であり、ａは０～６の整数である）。 The present invention will now be described in more detail.
The present invention is an alkynyl group-containing cyclic organopolysiloxane represented by the following formula (1).

(wherein R ¹ is a group independently selected from a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ² is each independently a hydrogen atom or a group represented by the following formula (A), provided that at least one of R ² is a group represented by the formula (A), and n is an integer of 3 to 6)

(wherein R ³ are each independently a hydrogen atom or a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, and a is an integer of 0 to 6).

Each R ¹ is independently a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, preferably a saturated aliphatic hydrocarbon group having 1 to 3 carbon atoms. , an aromatic hydrocarbon group having 6 to 8 carbon atoms. Examples of saturated aliphatic hydrocarbon groups include alkyl groups such as methyl group, ethyl group, propyl group and butyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; Among these, a methyl group is preferred. Examples of aromatic hydrocarbon groups include aryl groups such as phenyl group, tolyl group, naphthyl group and biphenyl group, and aralkyl groups such as benzyl group, phenylethyl group and phenylpropyl group. Among these, a phenyl group is preferred. R ¹ is most preferably a methyl group.

Each R ² is independently a hydrogen atom or a group represented by formula (A) above, provided that at least one of R ² is a group represented by formula (A) above. In formula (A), a is an integer of 0-6, preferably an integer of 0-3.

Each R ³ is independently a hydrogen atom or a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, preferably a hydrogen atom or a saturated aliphatic hydrocarbon group having 1 to 3 carbon atoms. Examples of saturated aliphatic hydrocarbon groups include alkyl groups such as methyl group, ethyl group, propyl group and butyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; Among these, R ³ is preferably a methyl group, and most preferably all R ³ are methyl groups. When R ³ is a methyl group, the effect of suppressing the addition reaction due to the chelating action of the acetylene group can be further improved, and a composition having excellent storage stability can be obtained.

In the above formula (1), n is the number of siloxane units. Said n is an integer of 3-6, preferably an integer of 3-5. Preferably, one or more, preferably two or more of the groups represented by R ² are alkynyl group-containing organic groups represented by the above formula (A), and at least one R ² is a hydrogen atom. good.

Preferably, in the above formula (A) ^, a = 0 and R3 is a hydrogen atom or a methyl group, most preferably an alkynyl group-containing organic compound represented by the following formula (a) or (b) group, most preferably a group represented by the following formula (b) from the viewpoint of storage stability.

Examples of the alkynyl group-containing cyclic organopolysiloxane represented by formula (1) include compounds represented by the following formula.

[Method for Producing Alkynyl Group-Containing Organopolysiloxane]
The alkynyl group-containing cyclic organopolysiloxane of the present invention can be produced, for example, by dehydrogenating acetylene alcohol and hydrosilyl group-containing cyclic organosiloxane in the presence of a catalyst such as trispentafluoroborane. The production method using the dehydrogenation reaction using a borane catalyst is desirable because it can prevent an unwanted increase in the molecular weight of the organopolysiloxane chain and yield the target alkynyl group-containing cyclic organopolysiloxane in high yield. Conditions for the dehydrogenation reaction may be adjusted as appropriate. For example, the reaction ratio of hydrosilyl groups and acetylene alcohol is 1:1.1 in terms of molar ratio.

The alkynyl group-containing organopolysiloxane can exhibit excellent effects as a reaction control agent for the hydrosilylation reaction. When the alkynyl group-containing organopolysiloxane is used as a reaction controller, it should be 0.001 to 5 parts by mass per 100 parts by mass of the alkenyl group-containing organopolysiloxane contained in the addition reaction curing silicone composition. is preferred, and 0.01 to 3 parts by mass is more preferred. The composition of the addition reaction-curable silicone composition is not particularly limited.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.
In the following examples, ¹ H-NMR measurements were carried out using a BRUKER apparatus (apparatus name: AVANCE III 400M) using deuterated chloroform as solvent and chloroform as internal standard.

^１Ｈ－ＮＭＲのケミカルシフト（ＴＭＳ基準、ｐｐｍ）と積分比は以下のとおりである。
δ０．２１－０．３０（ＯＳｉ（ＣＨ _３ ）_２）１２Ｈ
δ２．４２－２．４４（Ｃ≡ＣＨ）４Ｈ
δ４．３７－４．５１（ＯＣＨ _２ ）８Ｈ [Example 1]
0.08 g (1.7×10 ⁻⁴ mol) of trispentafluorophenylborane was added to the reactor and dissolved in 12 g of toluene. 6.1 g (0.10 mol) of 2-propyn-1-ol was added thereto, and the temperature was raised to 70°C. To this, 6.2 g (0.02 mol) of 1,3,5,7-tetramethylcyclotetrasiloxane was added dropwise over 30 minutes. After completion of the dropwise addition, the mixture was further heated and stirred at 70° C. for 3 hours. After heating, the mixture was cooled to room temperature (25° C.), and 1 g of a magnesium-aluminum solid solution (trade name: KW-2200, manufactured by Kyowa Chemical Industry Co., Ltd.) was added to adsorb and remove the trispentafluorophenylborane. Stir at room temperature for 1 hour. KW-2200 was removed by pressure filtration, and the remaining solvent was distilled off under reduced pressure to obtain an alkynyl group-containing cyclic organopolysiloxane (compound 1) represented by the following formula (A). ^{A 1} H-NMR chart is shown in FIG.

¹ H-NMR chemical shift (TMS standard, ppm) and integral ratio are as follows.
δ0.21-0.30( OSi ( _CH3 ) ₂ )12H
δ2.42−2.44(C≡C H )4H
δ 4.37-4.51 (OC H ₂ ) 8H

^１Ｈ－ＮＭＲのケミカルシフト（ＴＭＳ基準、ｐｐｍ）と積分比は以下のとおりである。
δ０．１９－０．２０（ＯＳｉ（ＣＨ _３ ）_２）１２Ｈ
δ１．５７－１．６０（Ｃ－ＣＨ _３ ）１８Ｈ
δ２．３９－２．４３（Ｃ≡ＣＨ）３Ｈ
δ４．７９（ＳｉＨ）１Ｈ [Example 2]
0.08 g (1.7×10 ⁻⁴ mol) of trispentafluorophenylborane was added to the reactor and dissolved in 25 g of toluene. 18.4 g (0.22 mol) of 2-methyl-3-butyn-2-ol was added thereto, and the temperature was raised to 70°C. To this, 6.6 g (0.03 mol) of 1,3,5,7-tetramethylcyclotetrasiloxane was added dropwise over 30 minutes. After completion of the dropwise addition, the mixture was further heated and stirred at 70° C. for 3 hours. After heating, the mixture was cooled to room temperature (25° C.), and 1 g of a magnesium-aluminum solid solution (trade name: KW-2200, manufactured by Kyowa Chemical Industry Co., Ltd.) was added to adsorb and remove the trispentafluorophenylborane. Stir at room temperature for 1 hour. KW-2200 was removed by pressure filtration, and the remaining solvent was distilled off under reduced pressure to obtain an alkynyl group-containing cyclic organopolysiloxane (compound 2) having an average structure represented by the following formula (B). ^{A 1} H-NMR chart is shown in FIG.

¹ H-NMR chemical shift (TMS standard, ppm) and integral ratio are as follows.
δ0.19-0.20( OSi ( _CH3 ) ₂ )12H
δ 1.57-1.60 (C—C H ₃ ) 18H
δ2.39−2.43(C≡C H )3H
δ4.79(SiH) 1H

[Preparation of addition-curable silicone resin composition]
[Example 3]
157 parts by mass of linear dimethylpolysiloxane (viscosity: 5,000 Pa s, vinyl group equivalent: 0.006 mol/100 g) having both ends of the molecular chain blocked with vinyl groups, and CH ₂ =CH(CH ₃ ) ₂ SiO _{Resin -} like _{organopolysiloxane} (weight _average molecular weight: _5,200 , vinyl group equivalent of 0.095 mol/100 g) and 8.1 parts by mass of an organohydrogenpolysiloxane whose average structural formula is represented by the following formula (C) were mixed until uniform. To this mixture, 0.059 parts by mass (1.29×10 ⁻⁴ mol, amount of acetylene: 5.2×10 ⁻⁴ mol) of compound 1 synthesized in Example 1 was added as a hydrosilylation reaction controller and mixed. After that, 0.2 parts by mass of 1,3-divinyltetramethyldisiloxane platinum (0) complex (platinum content 1.0% by mass) was added and mixed to prepare a silicone resin composition.

[Example 4]
Example 3 was repeated except that 0.084 parts by mass (1.7×10 ⁻⁴ mol, acetylene amount: 5.2×10 ⁻⁴ mol) of compound 2 was used instead of compound 1 in Example 3. , to prepare a silicone resin composition.

[Comparative Example 1]
0.044 parts by mass (5.2×10 ⁻⁴ mol, amount of acetylene: 5.2×10 ⁻⁴ mol) of 2-methyl-3-butyn-2-ol in place of compound 1 in Example 1 Example 3 was repeated except that a silicone resin composition was prepared.

[Discoloration resistance]
The silicone resin compositions prepared in Examples 3 and 4 and Comparative Example 1 were heat-molded at 150° C. for 4 hours to obtain cured products (10 mm×15 mm×5 mm). These cured products were subjected to heat and moisture resistance tests under conditions of 135° C. and 85% RH for 30 hours. The appearance and total transmittance of the cured product after the heat and moisture resistance test were compared with the initial appearance (before the test) and total transmittance to evaluate discoloration resistance.
For the heat/humidity resistance test, an unsaturated type highly accelerated life test device (device name: HASTEST PC-242HSR2) manufactured by Hirayama Seisakusho Co., Ltd. was used. Further, the total transmittance was measured using a spectrophotometer (apparatus name: U-4100) manufactured by Hitachi High-Technologies Corporation. Table 1 shows the results.

As shown in Table 1 above, the cured product obtained by curing the addition reaction curable composition of Comparative Example 1, in which the hydrosilylation reaction inhibitor is acetylene alcohol, turned yellow after the heat and moisture resistance test, and was resistant to heat. Poor discoloration.
In contrast, the cured product obtained from the addition reaction curing composition containing the alkynyl group-containing cyclic organopolysiloxane of the present invention as a reaction controller has high transparency before and after the heat and moisture resistance test. The compound is particularly preferred as a reaction controller for addition-curable organopolysiloxane compositions used for optical applications.

[Storage stability]
The viscosities at 23°C of the silicone resin compositions prepared in Example 4 and Comparative Example 1 were measured immediately after, 4 hours, and 7 hours after preparation to evaluate storage stability. Viscosity was measured using a Brookfield rotational viscometer. Table 2 shows the results.

The addition reaction curable composition of Comparative Example 1 gelled 4 hours after preparation. On the other hand, the composition of Example 4 containing the alkynyl group-containing cyclic organopolysiloxane (compound 2) of the present invention as a reaction control agent exhibited a suppressed increase in viscosity 4 hours and 7 hours after preparation, and had good storage stability. greatly improved.

The alkynyl group-containing cyclic organopolysiloxane of the present invention exhibits excellent effects as a reaction control agent for hydrosilylation reactions. In particular, it has excellent discoloration resistance after reliability tests such as heat and moisture resistance tests, so it is used as a reaction control agent for addition-curable organopolysiloxane compositions used in applications that require durability and transparency, such as LED sealants. Especially useful.

Claims (3)

A hydrosilylation reaction control agent comprising an alkynyl group-containing cyclic organopolysiloxane represented by the following formula (1)

(wherein R ¹ is a group independently selected from a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ² is each independently a hydrogen atom or a group represented by the following formula (A), provided that at least one of R ² is a group represented by the formula (A), and n is an integer of 3 to 6)

(wherein R ³ are each independently a hydrogen atom or a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, and a is an integer of 0 to 6). The group represented by the above formula (1) has at least one hydrogen atom bonded to a silicon atom and has at least one group represented by the above formula (A) bonded to a silicon atom. 2. The hydrosilylation reaction control agent according to claim 1. ^3. The hydrosilylation reaction controller according to claim 1, wherein a=0 and R3 is a hydrogen atom or a methyl group in the formula (A).

Images