JP3212248B2 - Method for producing acryloxy group-containing organopolysiloxane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an organopolysiloxane, and more particularly to a method for producing an acryloxy group-containing organopolysiloxane.

[0002]

2. Description of the Related Art Heretofore, as a method for producing an acryloxy group-containing organopolysiloxane, a method has been known in which an alkoxy group of an acryloxy group-containing alkoxysilane is hydrolyzed using a strongly nucleophilic acid as a catalyst. However, this method has a disadvantage that a side reaction occurs in which the acrylic ester portion is also hydrolyzed, and the by-product generated thereby adversely affects the reaction in the next step of the target substance and the physical properties of the final product. was there.

As a production method that does not cause a side reaction, there is disclosed a method in which an epoxy group-containing organopolysiloxane is reacted with acrylic acid, and then is reacted with acrylic acid chloride in the presence of a hydrochloric acid scavenger (Japanese Patent Laid-Open Publication No. H10-163,837). JP-A-63-135426). However, in this method, it is necessary to obtain an epoxy group-containing polysiloxane in advance by hydrosilylating a SiH group-containing polysiloxane (hydrogen polysiloxane) and an epoxy compound having an alkenyl group in the presence of a platinum catalyst. However, there is a disadvantage that the reaction is multi-step.

On the other hand, a hydrogen organopolysiloxane and an acrylate compound having an alkenyl group are
A method for hydrosilylation in the presence of a platinum catalyst is known (JP-A-48-47998). However, in this method, since the SiH group reacts with the alkenyl group contained in the acrylic compound and also reacts with the acrylic group, the hydrosilylation reaction cannot be selectively promoted, and the target acryloxy group cannot be obtained. There is a drawback that the yield of the alkyl group-containing organopolysiloxane is significantly reduced.

[0005]

The inventors of the present invention have conducted intensive studies to solve the above-mentioned drawbacks, and as a result, have found that when conducting a hydrosilylation reaction between a SiH group-containing organopolysiloxane and an alkenyl group-containing acrylate compound. ,
When a rhodium complex containing a phosphine compound was used as a catalyst, it was found that only the alkenyl group of the alkenyl group-containing acrylate compound was selectively hydrosilylated, and the present invention was reached. Accordingly, an object of the present invention is to provide a method for easily obtaining a high-purity acryloxy group-containing organosiloxane without a side reaction.

[0006]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
(A) A catalyst comprising a hydrogen polysiloxane having at least one SiH bond in one molecule and a (II) alkenyl group-containing acrylate compound and a monovalent rhodium complex having at least one phosphine compound as a ligand. This has been achieved by a method for producing an acryloxy group-containing polysiloxane, characterized by reacting as follows.

The hydrogenpolysiloxane having at least one SiH bond in one molecule used in the production method of the present invention is represented by the following structural unit formula (1) or (2). The structure may be linear, branched, or cyclic. (1) R _{a Hb} SiO _{(4-ab) / 2} (2) R _c SiO _{(4-c) / 2}

In the above formula, R _a and R _c represent an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, a cycloalkyl group such as a cyclohexyl group, an aryl group such as a phenyl group or a tolyl group, or A hydroxypropyl group, a cyanoethyl group, a 1-chloropropyl group, a hydroxy group, a cyano group, a halogen atom or the like in which part or all of the hydrogen atoms bonded to the carbon atoms of these groups have been substituted;
It can be selected from 3,3,3-trifluoropyr groups and the like, and particularly preferably has 1 to 10 carbon atoms. Here, a, b, and c are integers of 1 to 3, respectively, and a + b ≦ 3 and c ≦ 3.

In the acrylate compound having an alkenyl group (alkenyl acrylate) used in the production method of the present invention, the form of bonding between the alkenyl group and the acryloxy group is not particularly limited. Or a bond by a (poly) ether group.

The hydrosilylation reaction catalyst used in the production method of the present invention is the most important compound constituting the present invention. By using this catalyst, an alkenyl group, which is difficult with a platinum-based catalyst, can be specifically selected. And hydrosilylation can be easily carried out. In the present invention, at least one phosphine compound is used as the catalyst.
It is necessary to use a monovalent rhodium complex having one ligand.

Other than the monovalent rhodium complex, it does not become an efficient catalyst for the hydrosilylation reaction. Further, in the case of a monovalent rhodium complex having no phosphine compound as a ligand, although it serves as a catalyst for a hydrosilylation reaction, a side reaction easily proceeds, and only an alkenyl group cannot be selectively hydrolyzed.

Specific examples of the monovalent rhodium complex having at least one phosphine compound as a ligand include (PPh
_{3) 3 RhCl, (CO)} (PPh 3) 2 RhCl, (CO) (PPh 3) 3 RhH, (PBu 3)
₃ RhCl, (CO) (PBu ₃ ) ₂ RhCl, (CO) (PBu ₃ ) ₃ RhH, (PPh ₃ ) ₂ R
h (acac) and (CO) (PPh ₃ ) Rh (acac). However, acac in the formula is acetylacetone.
The coordination number of the phosphine compound coordinated with rhodium is 2-3.
It is preferred that

In the present invention, a catalyst is added to an alkenyl group-containing acrylate compound, the mixture is heated, and hydrogen polysiloxane having at least one SiH bond in one molecule is added dropwise to the solution to conduct a reaction. You can do it. The compounding ratio of the alkenyl group-containing acrylate compound and the hydrogen polysiloxane used here is SiH
The alkenyl group is preferably used in an amount of 1 to 100 equivalents, more preferably 1.5 to 10 equivalents to the bond.

The amount of the rhodium complex used as the catalyst is from 5 to 1,000 p per alkenyl group-containing acrylate compound.
pm, particularly 10 to 200 ppm
It is preferable that The reaction temperature of the hydrosilylation is not particularly limited as long as the reaction proceeds, but is preferably about 40 to 100 ° C. in the present invention.
In addition, the reaction time is not particularly limited as long as the reaction is terminated when the SiH bond disappears.

After the completion of the hydrosilylation reaction, the resulting acryloxy group-containing organopolysiloxane is cooled and, if necessary, subjected to an activated carbon treatment or the like.
It can be obtained by removing excess alkenyl group-containing acrylate compound and organic solvent using a strip or the like. When the molecular weight of the product is small, it can be purified by a distillation step.

The hydrosilylation reaction in the production method of the present invention can be carried out in an organic solvent. Solvents that can be used here include aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as hexane and isooctane, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and esters such as ethyl acetate. Is mentioned. In addition, a large excess of the alkenyl group-containing acrylate compound, which is a raw material for the reaction, can be used as a reaction solvent.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The acryloxy group-containing organopolysiloxane composition produced by the production method of the present invention, when irradiated with radiation, exhibits a releasable cured film. It can be used as a release paper coating material for adhesive labels.

[0018]

According to the production method of the present invention, since the alkenyl group of the alkenyl group-containing acrylate compound is selectively hydrosilylated, the acryloxy group-containing organosiloxane can be simply and efficiently produced without any side reaction. it can.

[0019]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Embodiment 1 Stirrer, thermometer, reflux condenser,
And a 1-liter four-necked flask equipped with a dropping funnel and 224 g of an alkenyl group-containing acrylate compound represented by CH ₂ = CHCOOCH ₂ CH = CH ₂ as a raw material and (CO) (PPh ₃ ) ₂ RhCl as a catalyst. 0.28 g of the rhodium complex was charged.

Next, after adjusting the temperature in an oil bath so that the internal temperature of the flask was 60 ° C., 222 g of a compound represented by the following formula 1 as hydrogen siloxane was added dropwise over 5 hours. After further aging at 70 ° C. for 2 hours, the product 2 was treated by a usual method and purified by distillation.
67 g were obtained.

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The product obtained has an IR spectrum and H
From the analysis results of the NMR spectrum, it was confirmed that the siloxane was an acryloxy group-containing siloxane represented by the following chemical formula 2.

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Embodiment 2 FIG. Stirrer, thermometer, reflux condenser,
And a 1-liter four-necked flask equipped with a dropping funnel, 125 g of an alkenyl group-containing acrylate compound represented by CH ₂ = CHCOOCH ₂ CH = CH ₂ as a raw material and (CO) (PPh ₃ ) ₂ RhCl ₂ as a catalyst. 0.08 g of the rhodium complex was charged.

Next, after adjusting the temperature in an oil bath so that the temperature inside the flask was 60 ° C., 200 g of a compound represented by the following formula 3 as hydrogen siloxane was added dropwise over 5 hours. After further aging at 70 ° C. for 2 hours, the product was treated and refined by a usual method to obtain a light yellow transparent liquid product having a viscosity of 115 cp.

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The obtained liquid product was confirmed to be an acryloxy group-containing siloxane represented by the following chemical formula 4 by analysis of the IR spectrum and the H-NMR spectrum.

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Comparative Example 1 0.20 g of a rhodium complex of (CO) (PPh ₃ ) ₂ RhCl was added to 0.50 g of a butanol solution of chloroplatinic acid
The reaction and purification were carried out in exactly the same manner as in Example 1, except for replacing with, to obtain 307 g of a product. The product obtained is IR
From the analysis results of the spectrum and the H-NMR spectrum,
It was confirmed that the siloxane was represented by the following chemical formula 5.

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Comparative Example 2 The reaction was carried out in exactly the same manner as in Example 1 except that the rhodium complex of (CO) (PPh ₃ ) ₂ RhCl (monovalent) was replaced by 0.16 g of rhodium complex of Rh (acac) ₃ (trivalent). Then, purification was performed, but the hydrosilylation reaction hardly proceeded.

Comparative Example 3 0.28 g of a rhodium complex of (CO) (PPh ₃ ) ₂ RhCl was replaced with a rhodium complex of (acac) Rh (CO) ₂ 0.10
The reaction and purification were carried out in exactly the same manner as in Example 1 except that g was used instead of g, to obtain 100 g of the desired product. In this case, 150 g of a plurality of by-products was further obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-84064 (JP, A) JP-A-7-279056 (JP, A) JP-A-4-169589 (JP, A) JP-A-62-162 164688 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 77/00-77/62 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] (1) At least one Si in one molecule
A hydrogen polysiloxane having an H bond, and
(B) reacting the alkenyl group-containing acrylate compound with a monovalent rhodium complex having at least one phosphine compound as a catalyst,
A method for producing an acryloxy group-containing polysiloxane.