JPH0618883B2 - Method for producing photocurable organopolysiloxane - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a photocurable organopolysiloxane which gives a transparent photocurable organopolysiloxane having stable viscosity and curability.

2. Description of the Related Art Conventionally, as a method for producing a photocurable organopolysiloxane, for example, one or more cyclic organopolysiloxanes and aminopropyldisiloxane are combined with an alkali metal oxide or an alkali metal oxide. In the presence of at least one basic catalyst such as an alkali metal-containing compound such as a metal hydroxide, an alkali metal alkoxide, an alkali metal aryl oxide, an alkali metal silanolate or a quaternary ammonium compound, or a basic catalyst and a cyclic compound thereof. After heating in the presence of polyether to carry out a ring-opening polymerization reaction to synthesize aminopolysiloxane, it is neutralized with ethylene chlorohydrin or the like to remove volatile low-molecular components in strips or the like. Add an acrylic acid derivative to diaminopolysiloxane A method for obtaining a curable organopolysiloxane has been proposed.

However, in the above method, the viscosity of the photocurable organopolysiloxane to be produced is difficult to stabilize, the curability varies, and the quality is unstable so that a cloudy white opaque oily product cannot be obtained. Had.

The present invention has been made to solve the above problems,
An object of the present invention is to provide a method for producing a photocurable organopolysiloxane which has a stable viscosity and curability, is transparent and has a good appearance.

Means and Actions for Solving the Problems As a result of extensive studies made by the present inventor to solve the above-mentioned object, (a) the following general formula [I] (Wherein, R ₁ and R ² are the same or different unsubstituted or substituted monovalent hydrocarbon groups, respectively, and l is an integer of 3 or more.), And (b ) The following general formula [II] (Wherein R ³ and R ⁴ are the same or different unsubstituted or substituted monovalent hydrocarbon groups, and m is an integer of 1 to 6) and a mixture with an aminoalkyldisiloxane. Is at least one basic catalyst selected from alkali metal oxides, hydroxides, alcoholates, aryl oxides and silanolates, or the basic catalyst and cyclic polyether, preferably the following general formula [III] (In the formula, R is an unsubstituted or substituted divalent hydrocarbon group, and n is an integer of 3 or more.) Equilibrium reaction product obtained by heating in the presence of a cyclic polyol represented by Amino group-containing polysiloxane) is neutralized with an aqueous solution of ammonium chloride, and more preferably stripped to reduce the content of volatile components to 2% by weight or less. Or Reacting with an acrylic acid derivative represented by
By using ammonium chloride aqueous solution as a neutralizing agent, the neutralization reaction proceeds completely, and sufficient stripping is performed to remove volatile low-molecular components that cause turbidity and destabilization of viscosity. When the addition reaction of the acrylic acid derivative is carried out at a relatively high temperature, especially 70 to 100 ° C., the main reaction selectively proceeds, has stable viscosity and curability, is transparent and has a good appearance, and is a high-quality photocurable organopolymer. The inventors have found that polysiloxane can be obtained, and have completed the present invention.

Accordingly, the present invention comprises a mixture of a cyclic organopolysiloxane of the above formula [I] and an aminoalkyldisiloxane of the above formula [II] selected from alkali metal oxides, hydroxides, alcoholates, aryl oxides and silanolates. It is heated in the presence of at least one basic catalyst or these basic catalysts and a cyclic polyether, and the resulting equilibrium reaction product is neutralized with an aqueous ammonium chloride solution, and more preferably stripped to remove volatile components. After adjusting the content to 2% by weight or less, preferably 7% with the above acrylic acid derivative.
Provided is a method for producing a photocurable organopolysiloxane, which comprises reacting at 0 to 100 ° C.

Hereinafter, the present invention will be described in more detail.

The starting materials for the photocurable organopolysiloxanes of the present invention are cyclic organopolysiloxanes and aminoalkyldisiloxanes.

Here, as the cyclic organopolysiloxane, the following general formula [I] (In the formula, R ¹ and R ² are the same or different monovalent organic groups, and l is an integer of 3 or more.).

In this case, examples of R ¹ and R ² include an alkyl group such as a methyl group, an ethyl group, a propyl group and an octyl group, a cycloalkyl group such as a cyclohexyl group and a cycloheptyl group, a vinyl group, an allyl group and a cyclohexenyl group. Alkenyl group, phenyl group, aryl group such as diphenyl group, benzyl group, aralkyl group such as phenylethyl group, 3,3,3-trifluoropropyl group, halogenated alkyl group such as chloromethyl group, chlorophenyl group,
Examples thereof include a halogenated aryl group such as a dibromophenyl group, a cyanomethyl group, a 2-cyanoethyl group, a cyanoalkyl group such as a 3-cyanopropyl group, and the like.

Specific examples of such a cyclic organopolysiloxane include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, 1,3,5,7-tetravinyl-1,3.
Examples include 5,7-tetramethylcyclotetrasiloxane.

The cyclic organopolysiloxane that is the starting material may be used alone or as a mixture of two or more. Further, one or more of these cyclic organopolysiloxanes may be used as a starting material in combination with a low molecular weight chain-like diorganopolysiloxane or a silane compound. It is preferable that the cyclic organopolysiloxane is blended in a proportion of at least 40% by weight.

The other starting material, aminoalkyldisiloxane, has the following general formula [II] And R ³ and R ⁴ in the formula are the same or different, unsubstituted or substituted monovalent hydrocarbon groups, and m is an integer of 1 to 6.

Here, examples of the substituents R ³ and R ⁴ include an alkyl group such as a methyl group, an ethyl group, a propyl group and an octyl group, a cycloalkyl group such as a cyclohexyl group and a cycloheptyl group, a vinyl group, an allyl group and a cyclohexenyl group. Groups such as alkenyl groups, phenyl groups, diphenyl groups such as aryl groups, benzyl groups, phenylethyl groups such as aralkyl groups, 3,3,3-trifluoropropyl groups, chloromethyl groups such as halogenated alkyl groups, chlorophenyl groups ,
A halogenated aryl group such as a dibromophenyl group, a cyanoalkyl group such as a cyanomethyl group, a 2-cyanoethyl group, and a 3-cyanopropyl group can be given.

In the present invention, the above cyclic organopolysiloxane and aminoalkyldisiloxane are used to synthesize an amino group-containing polysiloxane by utilizing the equilibrium reaction of both compounds, and the cyclic organopolysiloxane and aminoalkyldisiloxane are combined. The reaction is carried out in the presence of at least one basic catalyst selected from alkali metal oxides, hydroxides, alcoholates, aryl oxides and silanolates, or in the presence of these basic catalysts and cyclic polyethers.

In this case, examples of the basic catalyst include oxides of alkali metals such as sodium oxide and potassium oxide, hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide and lithium hydroxide, sodium methoxide and sodium ethoxide. Alkali metal alkoxides such as potassium ethoxide, alkali metal aryl oxides such as sodium phenoxide and potassium phenoxide,
Alkali metal silanolate compounds such as potassium salt of methylsilanetriol and potassium salt of phenylsilanetriol are mentioned, but potassium hydroxide is particularly preferable in the present invention. These basic compounds are not limited to one kind in use, and may be used as a mixture of two kinds or more.

The amount of the basic catalyst used is preferably 0.001 to 0.1% (% by weight, the same applies hereinafter) with respect to the cyclic organopolysiloxane of the formula [I], and more preferably 0.005 to 0.05%. .

Further, as the cyclic polyether, the following general formula [III] The one shown in can be used.

Here, R is a group selected from unsubstituted or substituted divalent hydrocarbon groups such as methylene, ethylene, propylene, 1,2-cyclohexylene, and 1,2-phenylene, and n is an integer of 3 or more. Is. Examples of such cyclic polyethers include crown ethers (Journal
Obj American Chemical Society 89
Vol. 7017 to 7036), specifically, benzo-15-crown-5, cyclohexyl-15-crown-5,2,3-naphtho-15-crown5,2.
3-decalyl-15-crown 5,18-crown-
6, dibenzo-18-crown-6, dicyclohexyl-18-crown-6, benzo-18-crown-6, cyclohexyl-18-crown-6, 2,3-naphtho-
18-crown-6, dibenzo-21-crown-7,
Dicyclohexyl-21-crown-7, dibenzo-2
4-crown-8, dicyclohexyl-24-crown-8, di (2,3-naphtho) -24-crown-8, dibenzo-30-crown-10, dicyclohexyl-3
0-crown-10 and the like. In the present invention, among others, 18-crown-6, dicyclohexyl-1
8-crown-6 and the like are preferred. In addition, such a cyclic ether can be easily synthesized by the method described in the above document.

Further, the amount of the cyclic polyether used is 0.003% or more, preferably 0.03% or more, based on the cyclic organopolysiloxane of the formula [I].
The amount used is preferably 0.003%
If it is less than%, the reaction may not proceed at low temperature in a short time.

In the production method of the present invention, the equilibration reaction between the cyclic organopolysiloxane of the formula [I] and the aminoalkyldisiloxane of the formula [II] is carried out by heating in the presence of the basic catalyst and the cyclic polyether. The heating temperature is not particularly limited, but is 80 to 180 ° C., particularly 140 to 160.
It is preferably in the range of ° C. The reaction time is 4 to
It can be 6 hours.

Further, the equilibration reaction may be carried out in an organic solvent.
As the organic solvent, for example, toluene and xylene are preferably used.

In carrying out the method of the present invention, for example, a mixture of one or two or more cyclic organopolysiloxanes of the formula [I] and a mixture of one or more aminoalkyldisiloxanes of the formula [II] are added to the above base. The amino group-containing polysiloxane can be obtained as an equilibrium reaction product by adding the volatile catalyst and adding the cyclic polyether thereto while heating and stirring.

Further, in the present invention, after neutralizing the amino group-containing polysiloxane of the equilibrium reaction product, stripping is performed to remove the volatile low-molecular component, and then reacted with an acrylic acid derivative to form a photocurable organopolysiloxane. To synthesize.

In this case, the neutralization treatment uses an aqueous solution of ammonium chloride, and the amount of ammonium chloride used is 2 times that of the basic catalyst.
~ 4 times mol, particularly preferably 3 to 4 times mol,
Further, an ammonium chloride aqueous solution having a concentration of 5 to 20%, particularly 5 to 10% is preferably used. When the neutralization treatment is performed with the ammonium chloride aqueous solution as described above, the neutralization reaction can be completely advanced, and the subsequent strip can be sufficiently performed.

Furthermore, the strip contains less than 2% of volatile low-molecular components (low-molecular siloxane) in the reaction product at 150 ° C./3 hours,
It is more preferable to perform it so that it is 1% or less, and preferably 160 to 180 ° C / 1 to 30 mm.
Hg, particularly 160 ° C. or higher / 2 mmHg or less, for 5 to 10 hours, particularly 8 to 10 hours.

Next, as the acrylic acid derivative to be reacted with the amino group-containing polysiloxane after stripping, the following formula is used. The glycidyl acrylate and the glycidyl methacrylate shown in each of are used.

When reacting the amino group-containing polysiloxane with the acrylic acid depositor, both compounds are used in a proportion of 2 mol or more, particularly 2 to 3 mol, per 1 mol of the amino group-containing polysiloxane. It is desirable to mix them under a nitrogen gas atmosphere. At this time, the reaction conditions include a temperature of 70 to 100 ° C, more preferably 80 to 90 ° C.
Is preferably 6 to 24 hours, more preferably 10 to 20 hours. By making the reaction temperature higher than that of the conventional method in this way, the selectivity of the main reaction is improved, the ring-opening addition reaction of the epoxy group proceeds, and the target photocurable organopolysiloxane can be efficiently obtained. If the reaction temperature is lower than 70 ° C., side reactions proceed and acrylic acid derivatives react one after another,
It may cause thickening or cloudiness, and the curability may decrease.

Effects of the Invention According to the production method of the present invention, a photocurable organopolysiloxane having excellent viscosity stability and transparency and stable curability can be synthesized. Therefore, when a sensitizer such as benzophenone is added to the photocurable organopolysiloxane of the present invention, the photocurable organopolysiloxane is rapidly cured by irradiation with ultraviolet rays, and changes into a cured product superior in properties to conventional products.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

In the following examples, all parts are parts by weight.

Example 1 Octamethylcyclotetrasiloxane (150 g) and 1,3-di-γ-aminopropyltetramethyldisiloxane (2.5 g) in potassium hydroxide (0.004 g) and cyclohexyl-18 crown-6 (0.006). g) is added,
After stirring at 140 to 160 ° C. for 5 hours, diaminopolysiloxane having an equilibrated viscosity of 400 cs was obtained. next,
Add 0.08 g of NH ₄ Cl 10% aqueous solution, stir at 50 ° C. for 2 hours, and then add the reaction solution at 160 ° C. for 2 mm.
When stripping was carried out with Hg, almost no distillate was produced after about 2 hours, and stripping was continued for another 3 hours. The viscosity after stripping was 637 cs, and the volatile content was 0.3% (150 ° C./3 hours).

Then, after filtering the generated salt, it was charged in a reaction tank, and a solution of 0.1 g of hydroquinone monomethyl ether dissolved in 8.6 g of glycidyl methacrylate was added, and the mixture was stirred at 90 ° C. for 10 hours. Is 21
00cs of oil was obtained. Further, excess glycidyl methacrylate was removed by stripping at 80 ° C. and 2 mmHg, resulting in an oil having a transparent viscosity of 3500 cs.
Dissolve 2 parts of benzophenone in 100 parts of this oil and irradiate with ultraviolet rays (irradiation conditions: high pressure mercury lamp 2 kw, irradiation distance 10
cm), a good rubber-like cured product (JIS
Hardness A, 25) according to K6301 was obtained.

[Comparative Example 1] After equilibrating the diaminopolysiloxane with the same charge amount and steps as in Example 1, the reaction solution was cooled, ethylene chlorohydrin 0.06 g was added, and the mixture was stirred at 120 ° C for 2 hours. And neutralize it, then further add this reaction solution.
When stripping was performed at 160 ° C. and 2 mmHg, the distillation did not stop even after 5 hours, and although it was a very small amount, it continued.
The strip was run for up to 7 hours with no change and stopped at this stage. Viscosity is 600cs and volatile content is 5% (150
(° C / 3 hours).

The product was then reacted with glycidyl methacrylate as in Example 1 to give a cloudy oil,
Further stripping resulted in a white opaque oil with a viscosity of 7600cs. After adding 2 parts of benzophenone to 100 parts of this oil, the curability by ultraviolet rays was examined. Under the same conditions as in Example 1, a rubber-like cured product (J
Hardness A, 25) according to IS K6301 was obtained.

[Example 2] Octamethyltetrasiloxane (355.2 g), 1,3-di-
γ-Aminopropyldisiloxane (24.8g) and potassium hydroxide (0.009g) and cyclohexyl-18-crown-6
(0.0135g) was added and stirred at 160 ° C for 3 hours.
A diaminosiloxane having an equilibrium viscosity of 67 cs was obtained. 0.18 g of 10% NH ₄ Cl aqueous solution was added to this diaminosiloxane.
Was added and neutralized and stripped in the same manner as in Example 1. As a result, aminopolysiloxane having a viscosity of 100 cs and a volatile content of 0.5% was obtained. Next, after filtering the salt, it was charged into a reaction tank, and a solution of 0.28 g of hydroquinone monoether dissolved in 87.6 g of glycidyl methacrylate was added and the reaction was carried out at 90 ° C. for 10 hours. It became oil. 80 ℃ for 2
When stripped at mmHg for 3 hours, 1200 cs of clear oil was obtained. Further, 1.0 part of benzophenone was dissolved and mixed in 100 parts of this oil, and was irradiated with ultraviolet rays under the same conditions as in Example 1. A hard rubber-like cured product (hardness A according to JIS K6301; 67) was obtained.

Comparative Example 2 In the same manner as in Example 2, the equilibration reaction of diaminosiloxane was neutralized with ethylene chlorohydrin and stripped (160 ° C./7 hours, volatile content 5%) and glycidyl methacrylate. When the reaction was carried out at 60 ° C., it became cloudy, and after 20 hours, it became a mixture of highly viscous gel and oil.

Claims (3)

[Claims] (A) The following general formula [I]: (Wherein R ¹ and R ² are the same or different unsubstituted or substituted monovalent hydrocarbon groups, respectively, and l is an integer of 3 or more.), And (b ) The following general formula [II] (Wherein R ³ and R ⁴ are the same or different unsubstituted or substituted monovalent hydrocarbon groups, and m is an integer of 1 to 6) and a mixture with an aminoalkyldisiloxane. Is heated in the presence of at least one basic catalyst selected from alkali metal oxides, hydroxides, alcoholates, aryl oxides and silanolates, or in the presence of the basic catalyst and a cyclic polyether, to obtain an equilibrium reaction product. After neutralizing the product with an ammonium chloride aqueous solution, Or A method for producing a photocurable organopolysiloxane, which comprises reacting with an acrylic acid derivative represented by: 2. After the neutralization treatment with the ammonium chloride aqueous solution, the content of volatile components is 2% by weight with a strip.
The method according to claim 1, wherein the reaction is carried out below and then with an acrylic acid derivative. 3. The reaction with the acrylic derivative is carried out at 70 to 1400 ° C.
The method according to claim 1 or 2, wherein