SILICON-CONTAINING POLYMER, FILM-FORMING COMPOSITION, METHOD FOR FORMING SILICON-CONTAINING POLYMER COATING, METHOD FOR FORMING SILICA COATING, AND PRODUCTION METHOD FOR SILICON-CONTAINING POLYMER

Abstract

The present invention aims to provide: a novel silicon-containing polymer that is alkali soluble or is soluble in an alkaline aqueous solution by using heat, etc.; a film-forming composition including the silicon-containing polymer; a method for forming a silicon-containing polymer coating using the film-forming composition; a method for forming a silica coating using the film-forming composition; and a production method for the silicon-containing polymer. The silicon-containing polymer including at least either a polysiloxane chain or oligosiloxane chain or a polysilane chain or oligosilane chain in the molecular chain thereof has a group that has e.g., a carboxy or carboxylic acid ester group and a sulfide group, introduced to the molecular chain as a result of an ene-thiol reaction.

Claims

1. A silicon-containing polymer, comprising at least one of poly-siloxane chain or oligo-siloxane chain and poly-silane chain or oligo-silane chain in a molecular chain, wherein one or more groups represented by a following formula (1) are bound onto a silicon atom in the silicon-containing polymer;
—R.sup.1—S—R.sup.2—(CO—O—R.sup.3).sub.n   (1) wherein, in the formula (1), R.sup.1 and R.sup.2 are each independently a hydrocarbon group having 1 or more and 10 or less carbon atoms, R.sup.3 is a hydrogen atom or an organic group having 1 or more and 20 or less carbon atoms and being bound to the oxygen atom via a C—O bond, and n is an integer of 1 or 2.

2. The silicon-containing polymer according to claim 1, wherein the molecular chain consists of the poly-siloxane chain or oligo-siloxane chain or of the poly-silane chain or oligo-silane chain.

3. The silicon-containing polymer according to claim 1, wherein the molecular chain is linear.

4. The silicon-containing polymer according to claim 1, wherein the number of moles of a group represented by the formula (1) is 0.05 mol or more and 2.0 mol or less with respect to 1 mol of silicon atom in the silicon-containing polymer.

5. The silicon-containing polymer according to claim 4, wherein the number of moles of a group represented by the formula (1) is 0.2 mol or more and 1.0 mol or less with respect to 1 mol of silicon atom in the silicon-containing polymer.

6. The silicon-containing polymer according to claim 1, wherein the R.sup.1 is an ethane-1,2-diyl group.

7. A film-forming composition, comprising the silicon-containing polymer (A) according to claim 1 and a solvent (S).

8. A method for forming a silicon-containing polymer coating, the method comprising: forming a coated film by applying the film-forming composition according to claim 7 onto a substrate, and drying the coated film.

9. A method for forming a silica-based coating, the method comprising: forming a coated film by applying the film-forming composition according to claim 7 onto a substrate, and drying the coated film to form a silicon-containing polymer coating and then baking the silicon-containing polymer coating or baking the coated film.

10. A production method for the silicon-containing polymer according to claim 1, the production method comprising: performing an ene-thiol reaction between a precursor polymer and a carboxylic acid derivative or an unsaturated group-containing compound, wherein the precursor polymer includes at least one of poly-siloxane chain or oligo-siloxane chain and poly-silane chain or oligo-silane chain in a molecular chain and an unsaturated hydrocarbon group or a mercapto group-containing group, the unsaturated hydrocarbon group is represented by a following formula (2-I):
—R.sup.4—CR.sup.5═CH.sub.2   (2-I) wherein, in the formula (2-I), R.sup.4 is a single bond or a hydrocarbon group having 1 or more and 8 or less carbon atoms, R.sup.5 is a hydrogen atom or a hydrocarbon group having 1 or more and 8 or less carbon atoms, and in cases where both R.sup.4 and R.sup.5 are hydrocarbon groups, a sum of the number of carbon atoms in the hydrocarbon group as R.sup.4 and the number of carbon atoms in the hydrocarbon group as R.sup.5 is 2 or more and 8 or less, the mercapto group-containing group is represented by a following formula (2II):
—R.sup.1—SH   (2-II) wherein, in the formula (2II), R.sup.1 is the same as the le in the formula (1), the unsaturated hydrocarbon group or the mercapto group-containing group is bound onto a silicon atom, the carboxylic acid derivative is represented by a following formula (1-I):
HS—R.sup.2—(CO—O—R.sup.3).sub.n   (1-I) wherein, in the formula (1-I), R.sup.2, R.sup.3, and n are the same as the R.sup.2, R.sup.3, and n in the formula (1), and the unsaturated group-containing compound is represented by a following formula (1-II):
CH.sub.2═CR.sup.7—R.sup.6—(CO—O—R.sup.3).sub.n   (1-II) wherein, in the formula (1II) R.sup.3 and n are the same as the R.sup.3 and n in the formula (1), R.sup.6 is a single bond or a hydrocarbon group having 1 or more and 8 or less carbon atoms, R.sup.7 is a hydrogen atom or a hydrocarbon group having 1 or more and 8 or less carbon atoms, and in cases where both R.sup.6 and R.sup.7 are hydrocarbon groups, a sum of the number of carbon atoms in the hydrocarbon group as R.sup.6 and the number of carbon atoms in the hydrocarbon group as R.sup.7 is 2 or more and 8 or less.

11. The production method for the silicon-containing polymer according to claim 10, the method comprising performing an ene-thiol reaction between the precursor polymer in which the unsaturated hydrocarbon group represented by the formula (2-I) is bound onto a silicon atom and the carboxylic acid derivative represented by the formula (1-I).

Description

EXAMPLES

[0151] The present invention will now be described in more detail by way of Examples, but the present invention is not limited to these Examples.

Synthesis Example 1

(Synthesis of Precursor Polymer (Methylvinylsilane Polymer))

[0152] In a round-bottom flask equipped with a three-way cock with an inner volume of 1000 ml, 43.45 g of granular magnesium (grain diameter 20 μm or more and 1000 μm or less), 5.26 g of tris(acetylacetonato)iron(III) as a catalyst, and 1.26 g of anhydrous lithium chloride were put. The atmosphere in the reactor was set to 50° C. and the pressure therein was reduced to 1 mmHg (=133 kPa) to dry the inside of the reactor (flask). After this, dry argon gas was introduced into the reactor, and 132.13 ml of tetrahydrofuran (THF) dried with sodium-benzophenone ketyl in advance was added to the reactor. Subsequently, the contents in the reactor were stirred at 25° C. for about 60 minutes. Next, 42.0 g (0.3 mol) of methylvinyldichlorosilane purified by distillation in advance was added to this reactor by a syringe and the reaction mixture in the reactor was stirred at 25° C. for about 24 hours. After completion of the reaction, 1000 ml of 1 N (=1 mol/L) hydrochloric acid was put in the reaction mixture, and a formed precursor polymer was then extracted by 500 ml of toluene. The toluene phase was washed with 200 ml of pure water ten times, and the toluene phase was then dried over anhydrous magnesium sulfate. Subsequently, toluene was distilled off from the toluene phase to give 35.81 g of a linear methylvinylsilane polymer (mass average molecular weight (Mw)4000).

Synthesis Example 2

[0153] A methylvinylsilane polymer was obtained as a precursor polymer in the same manner as in Synthesis Example 1, except that the stirring time after adding methylvinyldichlorosilane was changed to 12 hours. The mass average molecular weight (Mw) of the obtained methylvinylsilane polymer was 1900.

Synthesis Example 3

[0154] A methylvinylsilane polymer was obtained as a precursor polymer in the same manner as in Synthesis Example 1, except that the stirring time after adding methylvinyldichlorosilane was changed to 48 hours. The mass average molecular weight (Mw) of the obtained methylvinylsilane polymer was 7000.

Examples 1 to 3

[0155] In a 300 ml flask, 3.2 g of a precursor polymer described in Table 1, 2.4 g of thioglycolic acid, 0.32 g of AIBN, and 76 ml of tetrahydrofuran (THF) were put. The mixture in the flask was refluxed in an 80° C. water bath with stirring for about 6 hours. Subsequently, the mixture was dried in an evaporator to obtain a silicon-containing polymer having a 2-(carboxymethylthio)ethyl group as an objective substance. It was verified by IR that vinyl groups disappeared and carboxy groups were formed. The mass average molecular weights (Mw) of the obtained silicon-containing polymers are shown in Table 1.

TABLE-US-00001 TABLE 1 Molecular weight (MW) of Precursor polymer silicon-containing polymer Example 1 Synthesis Example 2 2500 Example 2 Synthesis Example 1 5700 Example 3 Synthesis Example 3 10000

[0156] 1 part by mass of each of the silicon-containing polymers obtained in Examples 1 to 3 was mixed with 4 parts by mass of cyclohexyl acetate and a film-forming composition was prepared. The film-forming composition obtained was applied to a substrate by spin coating, the substrate was prebaked at 90° C. for 2 minutes to form a film including the silicon-containing polymer on the substrate. The substrate having a film was immersed in an aqueous TMAH (tetramethyl ammonium hydroxide) solution for 5 seconds. Observing the substrate surface after immersion, the film on the substrate was confirmed to have been dissolved in all of Examples 1 to 3.