JPH069716A - Polymerization initiator based on polysiloxane ester containing azo group - Google Patents

Abstract

PURPOSE:To obtain a polymerization initiator with which an acrylic/silicone block copolymer which is useful as a coating composition or other polymer can be produced in a high yield to be applied on an agricultural vinyl film, by using as an active ingredient a polysiloxane ester which is an azo compound of a specific structure. CONSTITUTION:The initiator comprises a polysiloxane ester having an azo group and made up of repeating units represented by formula I, wherein R<1> is an alkyl or phenyl; R<2> is an alkyl or nitrile; a and b each is 1-6; and n is 1-200. The azo ester can be produced, for example, by reacting a dicarboxylic acid dihalide containing a polysiloxane segment, represented by formula II, with an azo glycol represented by formula III and, if necessary, with a dibasic acid dihalide represented by formula IV.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel azo group-containing polysiloxane ester-based polymerization initiator, more specifically, an acrylic-silicone block copolymer and other vinyls useful as a coating agent for agricultural vinyl-based films. -The present invention relates to an azo group-containing polysiloxane ester-based polymerization initiator which is preferably used as a polymerization initiator for producing a silicone-based block copolymer and can be produced in a high yield.

[0002]

2. Description of the Related Art Vinyl-silicone block copolymers have excellent heat resistance, cold resistance, water repellency, releasability, slip characteristics, weather resistance and resistance to vinyl polymers that silicone resins such as organopolysiloxane have. It has properties such as ozone properties, electrical properties, and gas permeability, and is expected to be used in the fields of coating agents, paints, gas permeable membranes, etc., especially vinyl films for agriculture. Is attracting attention as a coating agent.

Conventionally, as a method for producing this vinyl-silicone block copolymer, for example, a living anion polymerization method [“Journal of Applied Polymer.
Science (J. Appl. Polym. Sci.) "
Vol. 8, pp. 2707 (1964)] and hydrosilylation method ["Polymer", 22.
Vol. 5, No. 5, 668 (1981)]. However, all of these methods have drawbacks in that strict control of polymerization conditions is required and applicable vinyl monomers are limited.

As a solution to such a drawback,
General formula

[Chemical 4] (In the formula, each R ₁ is the same or different hydrogen atom, lower alkyl group or nitrile group, each R ₂ is the same or different hydrogen atom or lower alkyl group, each R ₃
Are the same or different hydrogen atoms, halogen atoms, unsubstituted alkyl groups or phenyl groups, p and q are 0 or an integer of 1 to 8, and m is an integer of 0 or 1 to 200). A method for polymerizing a vinyl-based monomer in the presence of an azo group-containing polysiloxane amide has been disclosed (JP-A 61-252230). In this method, the azo group-containing polysiloxane amide composed of the repeating unit represented by the general formula (I) is decomposed by heat or light to generate a radical having a polysiloxane segment, which acts as a polymerization initiator. At the same time, the segment is introduced into the polymer to efficiently obtain the desired vinyl-silicone block copolymer.

However, this method has a drawback that the azo group-containing polysiloxane amide comprising the repeating unit represented by the general formula (I) cannot be obtained in good yield.

For example, the azo group-containing polysiloxane amide has the general formula

[Chemical 5] (Wherein R ₂ , R ₃ , m and q have the same meanings as described above), a polysiloxane diamide represented by the general formula

[Chemical 6] (Wherein X is a halogen atom, R ₁ and p have the same meanings as described above), and the azo group-containing dibasic acid is converted into an acid halide. In that case, the yield is as low as 40% at the highest. That is, it is difficult to efficiently convert a dibasic acid containing an azo group, which is unstable to light and heat, into an acid halide, and therefore, an azo group-containing polycondensate containing a repeating unit represented by the general formula (I) is used. Siloxane amide cannot be produced in good yield, and the method for producing a vinyl-silicone block copolymer using this azo group-containing polysiloxane amide is not a practical method.

[0007]

Under these circumstances, the present invention is suitably used as a polymerization initiator for producing a vinyl-silicone block copolymer useful for various purposes, and The purpose of the present invention is to provide an azo group-containing polysiloxane compound that can be produced in high yield.

[0008]

The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, an azo group-containing polysiloxane ester having a specific structure was identified as a vinyl-silicone block copolymer. It has been found that the compound acts as a polymerization initiator for production and can be produced in high yield, and the present invention has been completed based on this finding.

That is, the present invention has the general formula

[Chemical 7] (In the formula, each R ¹ is the same or different alkyl group or phenyl group, each R ² is the same or different hydrogen atom, alkyl group or nitrile group, and a and b are each 1
To an integer of 6 and n is an integer of 1 to 200) and a polymerization initiator comprising an azo group-containing polysiloxane ester composed of repeating units represented by the formula (I).
A repeating unit represented by V) and (B) a general formula

[Chemical 8] (Wherein Y is a dibasic acid residue, R ² and b have the same meaning as described above), and a polymerization initiator comprising an azo group-containing polysiloxane ester is there.

The polymerization initiator of the present invention has the general formula (I
V) an azo group-containing polysiloxane ester comprising a repeating unit, or (A) an azo comprising a repeating unit represented by the general formula (IV) and (B) a repeating unit represented by the general formula (V). It is a group-containing polysiloxane ester.

R ¹ in the general formula (IV) is an alkyl group or a phenyl group, and each R ¹ may be the same or different. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl,
Mention may be made of linear or branched alkyl groups such as butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl. Also, R
² is a hydrogen atom, an alkyl group or a nitrile group, and each R ² may be the same or different. Examples of the alkyl group are the same as those exemplified in the description of the alkyl group for R ¹ . a and b are each an integer of 1 to 6, and n is an integer of 1 to 200.

On the other hand, Y in the general formula (V) represents a dibasic acid residue. The dibasic acid residue is not particularly limited, and examples thereof include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, fumaric acid, itaconic acid, terephthalic acid, isophthalic acid, phthalic acid. And the like.

An azo group-containing polysiloxane ester comprising a repeating unit (A), that is, the repeating unit represented by the general formula (IV), and a repeating unit (B), that is, the repeating unit represented by the general formula (V). The content ratio of the (A) unit and the (B) unit in is not particularly limited and is appropriately selected according to the application of the azo group-containing polysiloxane ester.

The average molecular weight of the azo group-containing polysiloxane ester used as the polymerization initiator of the present invention is 200.
It is preferably in the range of 0 to 100,000.

The compounds of the present invention have, for example, the general formula

[Chemical 9] A dicarboxylic acid dihalide containing a polysiloxane segment represented by the formula (wherein X ¹ is a halogen atom, R ¹ , a and n have the same meanings as described above);

[Chemical 10] An azo group-containing glycol represented by the formula (R ² and b have the same meaning as described above), and a general formula optionally used.

[Chemical 11] It can be produced by reacting with a dibasic acid dihalide represented by the formula (X ² in the formula is a halogen atom and Y has the same meaning as described above).

In this production method, it is not necessary to produce an azo group-containing dibasic acid dihalide, but the desired azo group-containing polysiloxane ester can be obtained in high yield.

The above reaction is preferably carried out in the presence of a base catalyst. Examples of the base catalyst include triethylamine, N, N-dimethylaniline, piperidine, pyridine, 1,5-diazabicyclo [4.8.0] nonene-5.
(DBN), 1,8-diazabicyclo [5.4.0] undecene-7 (DBU), tri-n-butylamine, sodium hydride, n-butyllithium and the like.

The reaction is usually carried out in a solvent. Examples of the solvent include ethers such as tetrahydrofuran, diethyl ether, dimethoxyethane and dioxane, halogenated hydrocarbons such as carbon tetrachloride, chloroform, methylene chloride and trichlene, n-hexane, petroleum ether, petroleum benzine, toluene and benzene. , Hydrocarbons such as xylene, acetonitrile, N, N
-Dimethylformamide, dimethylsulfoxide and the like can be mentioned. These may be used alone or in combination of two or more.

An azo group-containing glycol represented by the general formula (VII), a dicarboxylic acid dihalide having a polysiloxane segment represented by the general formula (VI), and an optional dibasic acid represented by the general formula (VIII). The ratio of the dihalide to be used is not particularly limited and may be appropriately selected. However, in order to obtain a target compound having a higher molecular weight, it is usually preferable to use the glycol and the dihalide in almost equimolar ratios.

The amount of the base catalyst used is
It is usually selected in a range of 0.5 to 8.0 times by mole with respect to the total amount of the dihalide. The amount of the solvent used is appropriately selected depending on the year of the reaction solution and the like, but is preferably in the range of 1 to 50 times by weight the total amount of the raw materials used.

The reaction temperature is preferably about -20 to 60 ° C, but is preferably in the range of -10 to 40 ° C in order to prevent decomposition of the azo group and to make the product have a high molecular weight. The reaction time depends on the reaction temperature and cannot be determined unconditionally, but it is usually about 0.1 to 48 hours, preferably 0.
5 to 5 hours. Regarding the reaction temperature, a method of gradually increasing from low temperature to room temperature may be adopted.

Recovery of the target compound from the reaction mixture thus obtained is appropriately carried out depending on the types of starting materials, base catalyst, solvent and the like used. For example, it can be easily carried out by adding water to a viscous reaction mixture diluted with a solvent to remove salts and bases, and then removing the solvent. If necessary, extraction and solvent washing may be further performed.

The azo group-containing polysiloxane ester of the present invention easily generates nitrogen gas by heating or light irradiation to generate a radical species. At this time, if various vinyl-based monomers are present, the polymerization rapidly occurs, and a block copolymer containing a polysiloxane segment is produced. Therefore, by heating or irradiating with light in the presence of the azo group-containing polysiloxane ester and the vinyl-based monomer, the azo group-containing polysiloxane ester acts as a polymerization initiator and at the same time, a radical species having a polysiloxane segment is generated. (AB) consisting of polysiloxane segment (A) and vinyl polymer segment (B), which is introduced into the produced polymer to efficiently produce an _n- type or ABA-type vinyl-silicone block copolymer can do.

The vinyl monomer used in the vinyl-silicone block copolymer is not particularly limited as long as it can be polymerized by a radical reaction, and examples thereof include styrene, methacrylic acid or esters thereof.
Acrylic acid or its ester, itaconic acid or its ester, vinyl chloride, acrylonitrile, vinyl acetate, ethylene, propylene, butadiene, vinylidene chloride, tetrafluoroethylene, chlorotrifluoroethylene and the like can be mentioned. This may be used alone,
You may use it in combination of 2 or more type.

The vinyl-silicone block copolymer is produced using the compound of the present invention in the presence or absence of a solvent or a dispersant. As the solvent or dispersant, for example, tetrahydrofuran, diethyl ether, dimethoxyethane, ethers such as dioxane,
Halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride and trichlene, petroleum ether, n-hexane, octane, petroleum benzine, benzene, toluene, xylene and other hydrocarbons, methanol, ethanol, isopropanol, t-butanol, etc. Alcohols,
Acetone, methyl ethyl ketone, methyl isobutyl ketone, ketones such as cyclohexanone, acetonitrile, water, N, N-dimethylformamide, dimethyl sulfoxide and the like can be mentioned. These may be used alone or in combination of two or more. If necessary, a polymerization regulator such as n-dodecyl mercaptan may be appropriately added to the reaction system.

The ratio of the azo group-containing polysiloxane ester of the present invention to the vinyl monomer used in the above polymerization reaction is determined by the molecular weight of the azo group-containing polysiloxane ester,
Although it depends on the content of the azo group and the like, it can be generally selected from a wide range, and it is usually suitable that the latter is about 0.5 to 1000 parts by weight relative to 1 part by weight of the former.

When the polymerization reaction is carried out by heating, the reaction temperature is usually 80 to 180 ° C., preferably 50 to 100.
It is selected in the range of ° C. The reaction time is usually 1 to 48.
It is about an hour, preferably 1 to 24 hours. On the other hand, when the polymerization reaction is performed by irradiation with light, the reaction temperature is usually 0 to
It is selected in the range of 60 ° C, preferably 20 to 50 ° C. The reaction time is usually about 1 minute to 12 hours, preferably 80 minutes to 5 hours. As a light source used for light irradiation, for example, a high pressure mercury lamp can be used. The irradiation light is preferably UV light because it rapidly photolyzes the azo group-containing polysiloxane ester to polymerize the vinyl-based monomer.

Thus, by using the compound of the present invention, a vinyl-silicone block copolymer can be produced extremely efficiently. Vinyl obtained
The content of the polysiloxane segment in the silicone block copolymer can be arbitrarily changed by, for example, changing the ratio of the compound of the present invention to the vinyl monomer, but the polysiloxane segment imparts each of the above properties, and It is desirable that the inherent properties of the vinyl polymer are impaired, and it is usually selected in the range of 0.1 to 50% by weight in the copolymer.

[0029]

INDUSTRIAL APPLICABILITY The azo group-containing polysiloxane ester of the present invention can be produced in an extremely high yield, and since it easily generates nitrogen gas by heating or light irradiation to generate radical species. At this time, if a vinyl-based monomer is present, it acts as a polymerization initiator and simultaneously forms a block copolymer containing a polysiloxane segment.

This vinyl-silicone block copolymer is a vinyl polymer having excellent heat resistance, cold resistance, water repellency, mold releasability, sliding property, weather resistance and resistance to silicone resins such as organopolysiloxane. It has properties such as ozone property, electrical property, and gas permeability, and is suitably used in the fields of, for example, coating agents, paints, gas permeable membranes.

[0031]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Production Example Production of Dicarbonyl Chloride Dimethyl Polysiloxane While introducing nitrogen gas into a reaction vessel equipped with a thermometer, a cooling pipe, and a stirrer, dimethyl polysiloxane containing carboxyl groups at both ends (trade name: X-22- 162C, manufactured by Shin-Etsu Chemical Co., Ltd.] 100 g, 250 ml of benzene and 18 g of phosphorus pentachloride were charged and heated under reflux for about 2 hours. After refluxing, benzene was distilled off to obtain dimethylpolysiloxane [compound (A)] containing carbonyl chloride at both ends.

This compound (A) has a C = O stretching vibration of 1720 cm ^-1 to 18 in the IR absorption spectrum.
It was confirmed by shifting to 00 cm ^-1 . Yield 97g (95% yield)

Example 1 Azo compound 2,2 'having a hydroxyl group at both ends while introducing nitrogen gas into a reaction vessel equipped with a thermometer and an agitator.
-Azobis (2-cyanopropanol) 2.48 g, triethylamine 2.7 g and chloroform 230 ml were charged. Then, while cooling with ice to 0 to 5 ° C, 30 g of the compound (A) obtained in Production Example and 75% of chloroform were added.
The mixed solution with ml was added dropwise over 1 to 1.5 hours. After completion of dropping, the mixture was stirred at 25 to 30 ° C. for about 4 hours, and then the produced triethylamine hydrochloride and the solvent were removed to obtain the desired azo group-containing polysiloxane ester.

This compound has an IR absorption spectrum of C =
O stretching vibration was confirmed by shifted from 1800 cm ^-1 to 1750 cm ^-1. Yield 31g (Yield 9
8%)

Example 2 In the same manner as in Example 1, 2.48 g of 2,2'-azobis (2-cyanopropanol) and 2.7 of triethylamine.
15 g of chloroform and 150 ml of chloroform were charged, and 15 g of the compound (A) obtained in the production example, 1.51 g of sebacic acid chloride and 75 ml of chloroform were cooled with ice at 0 to 5 ° C.
The mixed solution with was added dropwise over 1 to 1.5 hours. After completion of dropping, the mixture was stirred at 25 to 30 ° C. for about 4 hours, and then the produced triethylamine hydrochloride and the solvent were removed to obtain an azo group-containing polysiloxane ester containing a sebacic acid residue.

This compound has an IR absorption spectrum of C =
It was confirmed that the O stretching vibration was shifted from 1800 cm ⁻¹ to 1760 cm ⁻¹ . Yield 16.8 g (93% yield)

Example 3 In the same manner as in Example 2, 2.48 g of azo compound, 2.7 g of triethylamine, 15 g of compound (A), 1.29 g of terephthaloyl chloride, and chloroform 225 as a solvent.
The reaction was carried out using ml to obtain an azo group-containing polysiloxane ester containing a terephthalic acid residue. Yield 15.5g
(Yield 87%)

Example 4 While introducing nitrogen gas into a reaction vessel equipped with a thermometer, a cooling tube and a stirrer, methyl methacrylate monomer 70 was added.
Parts by weight, 30 parts by weight of n-butyl methacrylate monomer, 5 parts by weight of the azo group-containing polysiloxane ester obtained in Example 1, and 100 parts by weight of toluene as a polymerization solvent were added, and the reaction was performed at a temperature of 85 ° C. for a reaction time of 13 hours. I went. The conversion of polymerization is 99.0%, the molecular weight of the obtained polymer was 154000 _M W _{360000, M} N.
This polymer solution was useful as a coating agent for agricultural vinyl films.

Claims (2)

[Claims] 1. A general formula: (In the formula, each R ¹ is the same or different alkyl group or phenyl group, each R ² is the same or different hydrogen atom, alkyl group or nitrile group, and a and b are each 1
To 6 and n is an integer of 1 to 200). A polymerization initiator comprising an azo group-containing polysiloxane ester composed of a repeating unit represented by the formula: 2. (A) General formula: (In the formula, each R ¹ is the same or different alkyl group or phenyl group, each R ² is the same or different hydrogen atom, alkyl group or nitrile group, and a and b are each 1
A repeating unit represented by the formula (6), n is an integer of 1 to 200), and (B) the general formula: A polymerization initiator comprising an azo group-containing polysiloxane ester composed of a repeating unit represented by the formula (Y in the formula is a dibasic acid residue, R ² and b have the same meanings as described above).