JP2001288269A - Method for manufacturing organopolysiloxane emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a highly polymerized siloxane latex emulsion, with less by-production of low molecular siloxanes, useful as a fiber processing agent, a releasing agent, or a coating agent, all containing less volatile siloxanes. SOLUTION: The organopolysiloxane emulsion is characterized in that it is manufactured by a method wherein an emulsion mainly comprising (A) the organopolysiloxane described by general formula (1) with the ends blocked by alkoxy groups, (B) a surfactant and (C) water is polymerized in the presence of an acid or alkali catalyst and then neutralized. In general formula (1), Rs are the same or different univalent organic groups, Xs are the same or different alkyl groups, and 9<=n<=700.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an organopolysiloxane emulsion having a high degree of polymerization, and more particularly to a method for producing an organopolysiloxane emulsion having a low content of cyclic low-molecular siloxane.

[0002]

2. Description of the Related Art Highly polymerized organopolysiloxysans, especially emulsions of organopolysiloxanes having both ends reactive, have good curability by adding a crosslinking agent and a catalyst. It provides a composition and is suitably used for fiber treatment agents, release agents, and various coating applications.

[0003] Conventionally, as a method for producing an organopolysiloxane emulsion having a high degree of polymerization, a method is known in which a cyclic organopolysiloxane is emulsified and then emulsion-polymerized with an acid catalyst or an alkali catalyst. However, since this method is an equilibration reaction, about 10 to 15% of volatile cyclic low-molecular siloxane remains in the siloxane.

As a method for producing an organopolysiloxane emulsion having reduced volatile low-molecular siloxane, a method comprising polymerizing an emulsion comprising a hydroxyorganopolysiloxane at both ends and a catalyst at 40 ° C. or lower (Japanese Patent Laid-Open No. 4-178429). ), A method of emulsion-polymerizing a hydroxyorganopolysiloxane at both ends and an aminoxyorganopolysiloxane at both ends (JP-A-4-198321).
), A method of emulsion-polymerizing a hydroxyorganopolysiloxane at both ends in the presence of a specific sulfonic acid (Japanese Unexamined Patent Publication No.
No. 71522). However, it has been difficult to obtain an organopolysiloxane having a high degree of polymerization by a method using a hydroxyorganopolysiloxane at both ends.

The present invention has been made to improve the above circumstances, and an object of the present invention is to provide a method for producing an organopolysiloxane emulsion having a high degree of polymerization and a low cyclic low molecular siloxane content.

[0006]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that an organopolysiloxane having a terminal alkoxy group-capped organopolysiloxane represented by the following general formula (1) has been obtained. Polycondensation, especially 0-3
By performing polycondensation at a temperature of 0 ° C. for 5 to 200 hours, an organopolysiloxane having a high degree of polymerization can be obtained. In addition, this organopolysiloxane has a low content of cyclic low-molecular siloxane, and particularly has a small number of silicon atoms. The inventors have found that the content of cyclic low-molecular siloxane of 10 or less can be reduced to 6% by weight or less, and the present invention has been accomplished.

Accordingly, the present invention provides: (A) an organopolysiloxane having a terminal alkoxy group-capped organopolysiloxane represented by the following general formula (1):

[0008]

Embedded image (Wherein, R is the same or different monovalent organic group, X is the same or different alkyl group, 9 ≦ n ≦ 70
0. (B) A method for producing an organopolysiloxane emulsion, comprising subjecting an emulsion containing (C) water as a main component to polycondensation in the presence of an acidic or alkaline catalyst, followed by neutralization.

The organopolysiloxane obtained in the present invention has a low content of low-molecular siloxane, and therefore, the low-molecular siloxane volatilizes little during the treatment, so that the environmental pollution is low. Further, the degree of polymerization of the resulting organopolysiloxane is higher than that of the prior art and has excellent properties, and is useful as a fiber treatment agent, a release agent, and a coating agent.

Hereinafter, the present invention will be described in more detail.
In the method for producing an organopolysiloxane emulsion of the present invention, (A) an organopolysiloxane having a terminal alkoxy group blocked, (B) a surfactant, and (C) an emulsion containing water as a main component is polycondensed.

In this case, as the organopolysiloxane of the component (A), one represented by the following general formula (1) is used.

[0012]

Embedded image (Wherein, R is the same or different monovalent organic group, X is the same or different alkyl group, 9 ≦ n ≦ 70
0. )

Here, R is the same or different and is preferably a monovalent organic group having 1 to 20 carbon atoms, and methyl, ethyl,
Alkyl groups such as propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, cyclopentyl, cyclohexyl, cycloheptyl, phenyl,
Aryl groups such as tolyl, naphthyl, etc., alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, hexyloxy, heptyloxy, octyloxy, decyloxy, tetradecyloxy, alkenyl groups such as vinyl and allyl, and organic group structures of these In which a part of the hydrogen atom is replaced by a halogen atom or a polar group-containing organic group such as amino, acryloxy, methacryloxy, epoxy, mercapto, and carboxyl. Here, it is desirable that 90 mol% or more of R is a methyl group.

X is the same or different and preferably has 1 carbon atom
4 to 4 alkyl groups, methyl, ethyl, propyl,
And a butyl group. When the terminal group is a hydroxy group, the siloxane viscosity at the time of extraction is only about 150 Pa · s, and when it is higher than that, it is necessary to introduce a branch unit. When the terminal group is an alkoxy group, the siloxane viscosity at the time of extraction is 2,000 even without introducing a branching unit.
It is possible to increase the degree of polymerization to a raw rubber of Pa · s or more. In the present invention, trialkoxysilane, branched unit-containing organopolysiloxane, or the like may be used in combination as a branch unit. X is preferably a methyl, ethyl or propyl group from the viewpoint of the reaction. More preferred are a methyl group and an ethyl group.

The S in the organopolysiloxane
The content of the cyclic low-molecular siloxane having an i number of 10 or less is 6% by weight.
If the amount is larger, S in the siloxane polymer after polymerization
The content of the cyclic low-molecular siloxane having an i number of 10 or less is 6% by weight.
Therefore, it is preferable to use a resin whose low molecular weight siloxane content is adjusted to 6% by weight or less. In this case, if n is less than 9, it is difficult to adjust the content of the cyclic low-molecular siloxane having a Si number of 10 or less to 6% by weight or less.
If it is larger than 700, the stability at the time of emulsification deteriorates. Therefore, it is necessary that 9 ≦ n ≦ 700.

Next, the surfactant as the component (B) is
(A) for uniformly dispersing the component in water,
Although there is no particular limitation, for example, anionic surfactants such as alkyl sulfates, alkylbenzene sulfonates, and alkyl phosphates; and nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, and polyoxyethylene fatty acid esters. Activator, fourth
There are cationic surfactants such as quaternary ammonium salts and alkylamine acetates, and amphoteric surfactants such as alkyl betaines and alkyl imidazolines. These can be used alone or in combination of several kinds.

The amount of the component (B) to be used is appropriately selected, and 0.1 parts by weight of the component (B) is added to 100 parts by weight of the component (A).
It is preferably from 50 to 50 parts by weight, especially from 0.3 to 20 parts by weight.

In the present invention, the above-mentioned component (A),
After the component (B) is uniformly emulsified and dispersed in water as the component (C) using an emulsifying machine such as a homomixer or a homogenizer, the liquid temperature is preferably adjusted to 0 to 30 ° C., and if necessary, a catalyst may be used. As sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid, formic acid,
An acidic substance such as lactic acid or trifluoroacetic acid, or an alkaline substance such as potassium hydroxide, sodium hydroxide or ammonia is added, and the reaction is carried out for about 5 to 200 hours.
In this case, when an acid type surfactant such as alkylbenzene sulfonic acid is used as the surfactant as the component (B), it is not necessary to newly add a catalyst since it itself acts as a catalyst. When the polymerization time is shorter than 5 hours, the polycondensation reaction is insufficient. ~ 200
It is preferably time. More preferably, 10-1
00 hours. If the liquid temperature during the polymerization exceeds 30 ° C., the equilibration reaction proceeds preferentially, and there is a possibility that a large amount of low-molecular-weight siloxane may be by-produced. For this reason, the liquid temperature is preferably 30 ° C. or lower in order to allow the condensation reaction between the alkoxy groups to proceed preferentially. When the temperature is lower than 0 ° C, the emulsion stability is deteriorated by freezing, so that the temperature is preferably 0 to 30 ° C. The temperature is more preferably 0 to 25 ° C, still more preferably 0 to 20 ° C.

After completion of the polymerization, use an alkaline substance such as sodium carbonate, ammonia, sodium hydroxide or triethanolamine when an acidic catalyst is used, or acetic acid, formic acid, phosphoric acid or hydrochloric acid when an alkaline catalyst is used. What is necessary is just to neutralize with acidic substances, such as.

[0020]

EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples,% indicates% by weight.

Example 1 The content of a cyclic low molecular siloxane having a Si number of 10 or less is 2.7%, 500 g of a terminal alkoxyorganopolysiloxane (siloxane A) represented by the following formula, and a 15% aqueous solution of sodium lauryl sulfate 1
00g into a 2 liter polyethylene beaker,
After uniform emulsification with a homomixer, 350 g of water was gradually added for dilution, and the mixture was passed twice through a high-pressure homogenizer at a pressure of 50 MPa to obtain a uniform white emulsion. This emulsion was cooled to 5 ° C., 50 g of a 10% aqueous solution of dodecylbenzenesulfonic acid was added, and a polymerization reaction was carried out for 48 hours.
Thereafter, the emulsion was neutralized to pH 8 with 10 g of 3% aqueous ammonia to obtain "emulsion A". This emulsion had a non-volatile residue of 49.0% after drying at 105 ° C. for 3 hours.

[0022]

Embedded image

Example 2 "Emulsion B" was obtained in the same manner as in Example 1 except that the polymerization time was changed to 24 hours. This emulsion had a non-volatile residue of 49.5% after drying at 105 ° C. for 3 hours.

Example 3 Example 1 was repeated except that 50 g of a 28% aqueous lactic acid solution was used in place of 50 g of a 10% aqueous solution of dodecylbenzenesulfonic acid as a catalyst, and 10 g of 29% aqueous ammonia was used during neutralization. "Emulsion C" was obtained in the same manner. This emulsion had a non-volatile residue after drying at 105 ° C. for 3 hours of 49.7%.

Example 4 The procedure of Example 1 was repeated except that 50 g of an 18% aqueous acetic acid solution was used instead of 50 g of a 10% aqueous dodecylbenzenesulfonic acid solution and 10 g of 29% aqueous ammonia was used during neutralization. "Emulsion D" was obtained in the same manner. This emulsion had a non-volatile residue of 49.6% after drying at 105 ° C. for 3 hours.

Example 5 "Emulsion E" was obtained in the same manner as in Example 1 except that the polymerization temperature was changed to 20 ° C.
This emulsion had a non-volatile residue of 47.8% after drying at 105 ° C. for 3 hours.

Example 6 The content of a cyclic low molecular siloxane having a Si number of 10 or less was 2.1%, and a terminal alkoxyorganopolysiloxane (siloxane B) represented by the following formula was used, and the polymerization time was 96 hours. "Emulsion F" was obtained in the same manner as in Example 1, except that This emulsion had a nonvolatile residue of 4 after drying at 105 ° C. for 3 hours.
8.2%.

[0028]

Embedded image

[Comparative Example 1] Instead of the terminal alkoxy siloxane, the content of the cyclic low molecular siloxane having a Si number of 10 or less was 0.6%, and the terminal hydroxyorganopolysiloxane (siloxane C) represented by the following formula was used. "Emulsion G" was obtained in the same manner as in Example 1 except for the above. This emulsion had a non-volatile content of 49.7% after drying at 105 ° C. for 3 hours.

[0030]

Embedded image

Comparative Example 2 Emulsion H was prepared in the same manner as in Comparative Example 1 except that the polymerization time was changed to 120 hours.
I got This emulsion had a nonvolatile content of 48.1% after drying at 105 ° C. for 3 hours.

Comparative Example 3 500 g of dimethylcyclosiloxane (siloxane D) represented by the following formula and 100 g of a 15% aqueous solution of sodium lauryl sulfate were charged into a 2-liter polyethylene beaker, and uniformly emulsified with a homomixer. Add slowly and dilute, pressure 50M
The mixture was passed twice through a high-pressure homogenizer at Pa to obtain a uniform white emulsion. To this emulsion was added 50 g of a 10% aqueous solution of dodecylbenzenesulfonic acid, and a polymerization reaction was carried out at 50 ° C. for 24 hours, followed by aging at 15 ° C. for 24 hours. Thereafter, the mixture was neutralized to pH 8 with 12 g of 3% aqueous ammonia to obtain "Emulsion I". This emulsion is 1
The nonvolatile content after drying at 05 ° C. for 3 hours was 44.9%.

[0033]

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Table 1 shows the emulsion production conditions of the above Examples and Comparative Examples, and Table 2 shows the physical properties of the obtained emulsions.

[0035]

[Table 1]

[0036]

[Table 2]

[Content of cyclic low-molecular siloxane having Si number of 10 or less]
10 cc of hexane was added, and the mixture was shaken to extract the siloxane. The hexane phase was quantified by GPC analysis.

[Viscosity of extracted siloxane] Emulsion 20
0 cc was added to 800 cc of IPA while stirring to separate the siloxane, which was dried at 105 ° C. for 3 hours and measured with a rotational viscometer.

[Curability] To 100 g of the emulsion, (CH ₃ ) ₃ Si—O — [(CH ₃ ) (H) Si was used as a crosslinking agent.
—O] ₃₈ —Si (CH ₃ ) ₃ , 1 g of a 50% emulsion of an organopolysiloxane containing an Si—H and a 1 g of a 50% emulsion of dioctyltin dilaurate as a catalyst are mixed in a 5 g aluminum dish.
The state after drying at 5 ° C. for 2 hours was compared.

[0040]

According to the present invention, it is possible to produce a high-polymerization degree siloxane latex emulsion having a small amount of by-products of a low molecular siloxane, and these emulsions are a fiber treatment agent and a release agent having a small amount of volatile siloxane. It is useful as a coating agent.

Claims (3)

[Claims] (A) An organopolysiloxane having a terminal alkoxy group-capped group represented by the following general formula (1): (Wherein, R is the same or different monovalent organic group, X is the same or different alkyl group, 9 ≦ n ≦ 70
0. (B) A method for producing an organopolysiloxane emulsion, comprising subjecting an emulsion containing (C) water as a main component to polycondensation in the presence of an acidic or alkaline catalyst, followed by neutralization. 2. The polycondensation is carried out at a temperature of from 0 to 30.degree.
2. The method according to claim 1, wherein the method is performed for a time. 3. The process according to claim 1, wherein the organopolysiloxane in the organopolysiloxane emulsion has a content of a cyclic low-molecular siloxane having 10 or less silicon atoms of 6% by weight or less.