JP3032420B2 - Method for producing modified polysiloxane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a modified polysiloxane having a long-chain hydrocarbon group at a molecular terminal.

[0002]

2. Description of the Related Art Polysiloxanes having a long-chain alkyl group are more excellent in lubricity and miscibility with hydrocarbon materials than polydimethylsiloxanes having only a methyl group as a substituent. Therefore, it is widely used for cosmetic raw materials, release agents, lubricants and the like. In particular, as a use of a polysiloxane having a long-chain alkyl group at a terminal, a method of using it as a skin protective agent has recently been proposed (see US Pat. No. 5,232,693).

However, a conventional synthesis method of a polysiloxane having a long-chain alkyl group at a terminal is a method of reacting a 1-olefin with a polysiloxane having a Si-H group at a terminal under a platinum catalyst. Therefore, unless the molecular weight of the alkyl group component is low, it is difficult to synthesize, and it is difficult to increase the melting point. Alkyl groups that can be synthesized are often linear without branching, and it is difficult to control crystallization. there were. In addition, in this synthesis method, there is a possibility that the Si-H terminal may remain, but in order to avoid this, it is usual to use an olefin in excess. Moreover, there is a disadvantage that it is difficult to remove the residual olefin, and that the heavy metal catalyst also remains in the product.

[0004] Therefore, it has been desired to solve these problems, to develop a production method in which the control of the structure is easy and precise and there is no residual raw material and no generation of by-products. If polysiloxanes with long-chain alkyl groups can be produced with accurate structures and with reduced raw material and catalyst residue and by-product formation, they can be used in a wide range of applications such as cosmetic raw materials, release agents, lubricants, and heat transfer media. And a plurality of new functions can be provided.
An object of the present invention is to provide a method for producing such a polysiloxane having a long-chain alkyl group.

[0005]

Under such circumstances, the present inventors have conducted intensive studies, and as a result, the living polyethylene obtained after the living polymerization of ethylene is reacted with a cyclic siloxane, and the cyclic siloxane is further reacted with a hydroxyl group at a terminal. It has been found that a polysiloxane having a long-chain alkyl group at a terminal can be synthesized with good reproducibility by polymerizing a chain siloxane having the same or a mixture thereof in the presence of a catalyst, and completed the present invention. That is, the present invention comprises the following steps
(1) A method for producing a modified polysiloxane having a long-chain hydrocarbon group at a molecular terminal represented by the formula (I), wherein (1), (2), (3) and (4) are performed in this order. Is what you do.

[0006]

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(Wherein R ₁ and R ₂ represent an alkyl group having 1 to 6 carbon atoms, and (r + 2) R ₁ and (r + 2) R ₂ may be the same or different. R ₃ Is an average of 16 to 60 carbon atoms
0 is a linear or branched saturated hydrocarbon group, and r is a number of 0 or more. (1) C1-C6 linear or branched alkyl lithium /
A step of subjecting ethylene to living anionic polymerization using a tertiary diamine-based initiator. (2) The living polyethylene obtained in the above step (1) is reacted with the cyclic siloxane represented by the formula (II), and if necessary, silanolized by acid treatment to obtain a molecular fragment represented by the formula (III). A step of obtaining a modified polyethylene having a silanol group or a silanolate group at a terminal;

[0008]

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Wherein R ₁ and R ₂ represent an alkyl group having 1 to 6 carbon atoms, and p R ₁ and p R ₂ may be the same or different. Is a number.)

[0010]

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(Wherein R ₁ and R ₂ have the same meanings as in formula (II), and s represents a number of 1 to 7. R ₄ is a linear or branched alkyl group having 1 to 6 carbon atoms. A is hydrogen or lithium, and n is a number from 1 to 300.) (3) The modified polyethylene represented by the formula (III) obtained in the above step (2) and the above-mentioned formula (II) A) equilibrium polymerization of a cyclic siloxane represented by the following formula, a chain siloxane having a hydroxyl group at both terminals represented by the following formula (IV) or a mixture thereof in the presence of an acid catalyst or a base catalyst.

[0012]

Embedded image

(Wherein R ₁ and R ₂ represent an alkyl group having 1 to 6 carbon atoms, and q R ₁ and q R ₂ may be the same or different. Further, formula (II) May be the same or different from R ₁ and R _{2 in the} above. Q is a number of 1 or more.) (4) A step of neutralizing and dehydrating the product obtained in the above step (3).

Hereinafter, the production method of the present invention will be described in more detail. Step (1) is a step of conducting living anionic polymerization of ethylene with a linear or branched alkyllithium / tertiary diamine initiator having 1 to 6 carbon atoms. In this living anionic polymerization, an aliphatic hydrocarbon solvent is used. Specific examples of such a solvent include pentane,
Hexane, heptane, octane, cyclohexane, cyclopentane and the like can be mentioned.

The linear or branched alkyl lithium having 1 to 6 carbon atoms includes methyl lithium, ethyl lithium, n
-Butyl lithium, tert-butyl lithium, sec
-Butyl lithium, isobutyl lithium and the like. As the tertiary diamine, the number of carbon atoms between two nitrogens is 2
Three to three are preferably used, and two are particularly preferred. Specific examples of such a diamine include tetramethylethylenediamine, dipiperidinoethane, dipyrrolidinoethane, sparteine, and the like. These tertiary diamines are usually used in an amount of 0.1 to 10 equivalents to alkyl lithium. If the amount of the amine used is less than 0.1 equivalent, the polymerization becomes very slow, and if it exceeds 10 equivalents, the living terminal is inactivated and the desired molecular weight is not reached.

Living polymerization of ethylene is carried out by introducing ethylene into a solution containing the above-mentioned alkyllithium and tertiary diamine. There is no particular limitation on the pressure for introducing ethylene, but 1 kg / cm ² to 100 kg / cm ² is appropriate. 1kg /
At low pressures below cm ^{2 the} polymerization reaction is too slow and not economic. On the other hand, at a high pressure exceeding 100 kg / cm ² ,
The polymerization is too fast to control the reaction. The polymerization temperature is not particularly limited, but is suitably from 0 ° C to 100 ° C. The temperature is preferably from 20C to 80C. If the temperature is lower than 0 ° C., the polymerization reaction is extremely slow, and the resulting living polyethylene is undesirably precipitated at a low molecular weight. If the temperature exceeds 100 ° C., the terminal of the living room is deactivated, which is not preferable. The polymerization time varies depending on the polymerization temperature, the tertiary diamine concentration, the ethylene introduction pressure and the like, but is generally about 0.1 to 24 hours. However, it is preferable that the time is as short as possible to remove the heat of polymerization from the viewpoint of preventing the deactivation of the living terminal. The average molecular weight of the produced polyethylene can be accurately controlled by changing these polymerization conditions.

In the step (2), the living polyethylene produced in the above step (1) is reacted with the cyclic siloxane represented by the above formula (II), and if necessary, silanolized by acid treatment to give the above formula (III) This is a step of obtaining a modified polyethylene represented by the following formula: In the formulas (II) and (III), R ₁ and R ₂
Is an alkyl group having 1 to 6 carbon atoms, and specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group and a tert-butyl group.

In the formula (III), the A atom at the end of the siloxane is hydrogen or lithium, and a mixture thereof is also included. In the formula (III), the degree of polymerization (n) of ethylene is 1 to
300. If the degree of polymerization exceeds 300, the concentration of the terminal silanol group or silanolate group is too low, which is not preferable.

The number of siloxane units (s) varies depending on the cyclic siloxane to be reacted, as described later.
The minimum is 1 unit and the maximum is the number of siloxane units of the cyclic siloxane represented by the formula (II), but it is possible in principle to increase the number to 7 or more by using a macrocyclic one. Further, s may be different for each molecule.

The amount of the cyclic siloxane represented by the formula (II) is not particularly limited as long as the molar amount of the siloxane unit is equal to or greater than the molar amount of the living polyethylene. However, considering the suppression of side reactions, etc., 2
It is preferable to use at least twice the molar amount. The cyclic siloxane represented by the formula (II) may be added to the living polyethylene solution as it is or as a hydrocarbon solution, as long as it is promptly performed with sufficient stirring. However, in order to avoid a side reaction in which two living polyethylenes react with one silicon atom, the living polyethylene solution is gradually added to the cyclic siloxane previously diluted in a hydrocarbon solvent with sufficient stirring. Is particularly preferred.

The reaction temperature is not particularly limited, but is 0 ° C to 1 ° C.
00 ° C is appropriate. The temperature is preferably from 20C to 80C. 0 ° C
If the temperature is lower than 100 ° C., the living polyethylene precipitates, which is not preferable. Generally, it is carried out at around the polymerization temperature of ethylene.
Since this reaction occurs quickly in the above-mentioned temperature range, a reaction time of about several minutes is sufficient. However, when the product precipitates, several hours may be required. Usually 30 minutes ~
Perform for about 5 hours.

The product thus obtained is a polyethylene modified with a silanolate group at one end where A is lithium in the formula (III). If necessary, the polyethylene is neutralized and modified with a silanol group at one end where A is a hydrogen atom. Polyethylene is obtained. Neutralization is performed by adding an acid equivalent to the amount of the initiator used to the obtained one-end silanolate group-modified polyethylene to make it neutral, and removing salts formed by washing with water. However, when a solid acid is used, it can be removed by filtration. Thus, one-terminal silanol group-modified polyethylene can be synthesized in high yield, but in some cases, purification such as reprecipitation can be performed.

Most of the products of this reaction are silanols or silanolates having 1 to 7 siloxane units at the polyethylene terminals, but depending on the reaction conditions and the like, dehydration coupling products may be produced as by-products. Since this coupling product undergoes the same reaction as silanol in the next step, there is no particular problem in synthesis, but it may be decomposed into two molecules of silanol or silanolate by hydrolysis if necessary. .

In the step (3), the compound of the formula (I) synthesized in the step (2) is used.
A modified polyethylene represented by the formula (II) and a cyclic siloxane represented by the formula (II), a chain siloxane having a hydroxyl group at both terminals represented by the formula (IV), or a mixture thereof is treated with an acid catalyst or This is a step of performing equilibrium polymerization in the presence of a base catalyst. In the formula (IV), R ₁ and R ₂ are an alkyl group having 1 to 6 carbon atoms, and are specifically the same as in the case of the formula (II). There is no particular limitation on q as long as it is 1 or more,
From the viewpoint of viscosity and solubility in the reaction solvent, it is preferably from 1 to 3000.

The molecular weight of the produced polysiloxane is not limited, but the modified polyethylene represented by the formula (III) synthesized in the above step (2) and the cyclic siloxane represented by the formula (II) and / or the formula (II) The molecular weight can be arbitrarily determined by the number of moles charged with the linear siloxane having a hydroxyl group at both terminals represented by the formula (IV). As specific examples of the catalyst, an inorganic acid such as sulfuric acid, a sulfonic acid such as methanesulfonic acid, and a solid acid such as an ion exchange resin are preferably used as an acid catalyst. As the base catalyst, a hydroxide of an alkali metal such as potassium hydroxide, a tetraalkylammonium hydroxide, a silanolate prepared from a tetraalkylammonium hydroxide and a cyclic siloxane, and the like are suitably used.
The amount of the catalyst to be added is not particularly limited, but about 0.01 to 1% by mole based on the number of moles of the siloxane unit is sufficient.

In this step, a solvent may be appropriately added in order to increase the solubility of the catalyst or the compatibility between the raw materials. Specific examples of such a solvent include aromatic hydrocarbons such as toluene and aliphatic hydrocarbons such as octane. The reaction temperature is not particularly limited, but is suitably from 20 ° C to 300 ° C. Preferably it is 60 to 200 ° C. If the temperature is lower than 20 ° C., the reaction system becomes non-uniform.
The reaction time varies considerably depending on the reaction conditions such as the amount of the raw materials charged, the temperature and the like, but it is usually carried out for about 8 hours to 7 days.

Step (4) is a step of neutralizing and dehydrating the product obtained in step (3). Up to the above step (3), a polysiloxane having an acid or base catalyst remaining at the terminal is formed. Therefore, neutralization is carried out, and all the remaining terminals of the catalyst are converted into neutral silanol. In this step, a base or an acid calculated from the amount of the catalyst is added to make it neutral. Here, when an insoluble salt is generated, it can be easily removed by washing with water. However, when a solid acid is used, it can be removed by filtration, and when a tetraalkylammonium hydroxide is used as a base, it can be removed by a thermal decomposition treatment. The silanol generated here is heated and dehydrated by a device equipped with a dehydration tube to cause a coupling reaction to obtain a product. The dehydration reaction is performed neat when the polysiloxane has a low molecular weight and low viscosity, but is dehydrated by refluxing in a hydrocarbon solvent such as toluene when the viscosity is high. The product can be obtained by distilling off the solvent. In some cases, purification such as reprecipitation is performed.

Thus, a polysiloxane having a long-chain hydrocarbon group at a molecular terminal represented by the formula (I) is obtained. In the formula (I), R ₁ and R ₂ represent an alkyl group having 1 to 6 carbon atoms, and are specifically the same as in the above (II) and (III).

In the formula (I), R ₃ is selected from an average of 16 carbon atoms.
A linear or branched saturated hydrocarbon group of 600 is shown, preferably having an average carbon number of 27 to 300, more preferably an average carbon number.
27-100. If the average carbon number is less than 16, the product becomes oily, and has poor pluggability and poor compatibility with hydrocarbon-based raw materials. On the other hand, if it exceeds 600, the effect of the polysiloxane is not exhibited, and compatibility with the polar base, heat resistance, gloss of the compound, and the like are lost. Examples of the branched saturated hydrocarbon group represented by R ₃ include those having a short-chain branch having 1 to 5 carbon atoms at the fifth carbon atom counted from the end of the long-chain alkyl group. Specific examples of the branch include a 2-methyl group, a 3-methyl group, and a 2,2-dimethyl group. These terminal branched chains have the effect of lowering the melting point of the product when the alkyl group chain length is short, but have no effect on other physical properties.

In the formula (I), r is a number of 0 or more, preferably 3000 or less, more preferably 2000 or less. When r exceeds 3,000, the effect of the long-chain alkyl group is lost, and lubricity and blocking property are lost. Further, the viscosity at the time of dissolution becomes too high, and the miscibility becomes poor.

[0031]

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.

Example 1 In a 1-liter autoclave purged with nitrogen, 400 ml of dry cyclohexane, 3 ml of tetramethylethylenediamine,
12.5 ml of n-butyllithium (1.6 mol / l) (0.02
Mol), and while maintaining the temperature of the reaction system at 30 ° C. and the ethylene gas introduction pressure at 2 kg / cm ² , the ethylene
One liter was introduced to perform living polymerization. Thereafter, ethylene gas was removed and the atmosphere was replaced with nitrogen. A solution of 11.8 g of octamethylcyclotetrasiloxane and 10 ml of dry cyclohexane was previously prepared in a 1-liter eggplant flask, and the above-mentioned polymerization mixture was added dropwise thereto under a nitrogen stream. After completion of the dropwise addition, the mixture was reacted at 30 ° C. for 1 hour, and then the reaction mixture was poured into 2 liters of methanol. After stirring for 1 hour, the resulting solid was collected by filtration under reduced pressure and dried in an oven at 50 ° C. under vacuum for 24 hours to obtain a white waxy solid. The yield of the product was 12.0 g, and the number average molecular weight was 610 and the molecular weight distribution was 1.03 as a result of GPC analysis (orthodichlorobenzene, manufactured by Waters, 135 ° C., calibrated with a polyethylene standard sample). ^{As a result of 1} H-NMR analysis (manufactured by Bruker, 200 MHz, chloroform-d, 50 ° C., TMS was used as a standard), the methyl group bonded to the silyl group at −0.05 ppm (singlet), 0.4 ppm ( A signal of a methylene group bound to a silyl group was observed in (triplet), a starting methyl group was observed in 0.8 ppm (triplet), and a methylene group in the main chain was observed at about 1.2 ppm. From the integration ratio of each signal, it was found that the terminal silanol group introduction rate was 99%. The number of siloxane units introduced is an average per polyethylene end.
1.4 pieces.

Next, in a 1-liter separable flask equipped with a condenser, 12.0 g of the above-mentioned silanol group-modified polyethylene, 88 g of octamethylcyclotetrasiloxane, and 100 ml of toluene were placed. Heated. When all the raw materials were uniformly dissolved, 0.01 g of potassium hydroxide was added, and reflux was continued for 48 hours. Thereafter, 0.18 ml of a 1N alcoholic hydrochloric acid solution was added, and the mixture was sufficiently stirred. Add water and p
After confirming that H was 7, the inorganic salt generated by water was extracted. Washing was carried out three times with heating, a Dean-Stark tube was attached in place of the condenser, and toluene reflux was carried out until complete dehydration. The toluene was distilled off to obtain a brittle rubbery white wax. The yield of the product was 96 g. As a result of GPC analysis (manufactured by Waters, ortho-dichlorobenzene, 135 ° C., polystyrene conversion), the weight-average molecular weight was 18,600, and the molecular weight distribution was 2.03. ¹ H-NMR
Analysis (manufactured by Bruker, 200 MHz, chloroform-d, 50 ° C.,
The standard used was TMS. ) Results in -0.05 ppm (singlet) of methyl groups bonded to silyl groups, 0.4 ppm (triplet) of methylene groups bonded to silyl groups,
A signal of a starting methyl group was observed at 0.8 ppm (triplet), and a signal of a methylene group of a polyethylene chain was observed at about 1.2 ppm. From the integral ratio of each signal, it was found that the weight ratio of the polyethylene portion to the siloxane portion was 10:90.

Comparative Example 1 In a 1 liter separable flask equipped with a condenser, 94 g of hydrogen-terminated polysiloxane (PS542, Mw = 17500, manufactured by Chisso Corporation) and Dialen 30 (manufactured by Mitsubishi Kasei Corporation: C) ₃₀ or more α- olefin mixture (using an average C ₃₈₎₎ 6g, toluene 100ml
And add 100 ppm of chloroplatinic acid in terms of platinum at 80 ° C.
The reaction was performed for 24 hours. After reprecipitation purification, a slightly brown soft wax was obtained. The yield was 96 g, ¹ H-NMR analysis, IR
As a result of the analysis, the residual ratio of terminal hydrogen was 10%, and the residual ratio of olefin was 5%.

Comparative Examples 2 to 4 The same procedures as those of Comparative Example 1 were carried out except that the charged amount of dialen 30 and the reaction conditions were changed as shown in Table 1. Table 1 shows the synthesis results.

[0036]

[Table 1]

Examples 2 to 3 The same procedure as in Example 1 was carried out except that the initiator was changed as shown in Table 2. Table 3 shows the synthesis results together with the results of Example 1.

[0038]

[Table 2]

[0039]

[Table 3]

Examples 4-5 The amounts of ethylene introduced, the polymerization temperature, the charged amount of the terminal silanol-modified polyethylene, the charged amount of octamethylcyclotetrasiloxane, and the polymerization conditions of the polysiloxane were changed as shown in Tables 4 and 5. The experimental operation and procedure were performed in the same manner as in Example 1. However, in Example 5, for polymerization of ethylene, a high pressure-resistant stainless steel autoclave was used. Table 4 shows the synthesis results of the terminal silanol-modified polyethylene, and Table 5 shows the synthesis results of the polysiloxane, together with the results of Example 1.

[0041]

[Table 4]

[0042]

[Table 5]

Examples 6 to 7 The same procedures as in Example 1 were carried out except that the charged amounts of the terminal silanol-modified polyethylene and octamethylcyclotetrasiloxane were changed as shown in Table 6. The synthesis result
Table 6 shows the results of Example 1.

[0044]

[Table 6]

[0045]

According to the present invention, a polysiloxane having a long-chain alkyl group at a molecular terminal can be obtained in high yield. In particular, since the polysiloxane obtained in the present invention obtains a long-chain alkyl group at the molecular end by living anionic polymerization of ethylene, the control of the chain length of the alkyl group is precise,
It is easy to increase the molecular weight. Therefore, it is easy to provide expected physical properties. In addition, using a catalyst that is easy to remove,
Since the residual amount of raw materials and intermediates is extremely small, the safety of the product is high.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 77/42 C08G 77/38 C08G 77/442

Claims (1)

(57) [Claims] 1. A modified compound having a long-chain hydrocarbon group at a molecular terminal represented by the formula (I), wherein the following steps (1), (2), (3) and (4) are performed in this order. Method for producing polysiloxane. Embedded image (Wherein, R ₁ and R ₂ represent an alkyl group having 1 to 6 carbon atoms;
(R + 2) R ₁ and (r + 2) R ₂ may be the same or different. R ₃ is a linear or branched saturated hydrocarbon group having an average of 16 to 600 carbon atoms, and r is a number of 0 or more. (1) C1-C6 linear or branched alkyl lithium /
A step of subjecting ethylene to living anionic polymerization using a tertiary diamine-based initiator. (2) The living polyethylene obtained in the above step (1) is reacted with the cyclic siloxane represented by the formula (II), and if necessary, silanolized by acid treatment to obtain a molecular fragment represented by the formula (III). A step of obtaining a modified polyethylene having a silanol group or a silanolate group at a terminal; Embedded image (Wherein, R ₁ and R ₂ represent an alkyl group having 1 to 6 carbon atoms;
p R ₁ and p R ₂ may be the same or different.
p is a number from 3 to 7. ) (Wherein R ₁ and R ₂ have the same meaning as in formula (II), and s is 1
1 to 7 are shown. R ₄ is a linear or branched alkyl group having 1 to 6 carbon atoms, A is hydrogen or lithium, and n is 1
Number of ~ 300. (3) The modified polyethylene represented by the formula (III) obtained in the above step (2), the cyclic siloxane represented by the above formula (II), and both ends represented by the following formula (IV) A step of carrying out equilibrium polymerization of a chain siloxane having a hydroxyl group or a mixture thereof in the presence of an acid catalyst or a base catalyst. Embedded image (Wherein, R ₁ and R ₂ represent an alkyl group having 1 to 6 carbon atoms;
q R ₁ and q R ₂ may be the same or different.
Further, R ₁ and R ₂ in the formula (II) may be the same or different. q is a number of 1 or more. (4) A step of neutralizing and dehydrating the product obtained in the above step (3).