Ladder-type polysiloxane and method for producing the same

Abstract

To provide a ladder-type polysiloxane which can be synthesized easily, and a method for producing the same.SOLUTION: A ladder-type polysiloxane has a structure represented by formula 1 or formula 2. In formula 1 and formula 2, each R1 independently represents an alkyl group having 1 to 3 carbon atoms; each R2 independently represents an alkyl group having 1 to 3 carbon atoms; Z represents an alkylene chain having 2 to 4 carbon atoms; and n represents a positive real number. In formula 2, each R3 independently represents an alkyl group having 1 to 3 carbon atoms.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a ladder-like polysiloxane and a method for producing the same. [Background technology]

[0002] Polymer materials are widely used in various fields. One of the problems with polymer materials is their degradation due to heat and light. This degradation reaction occurs when hydrogen is extracted by energy such as heat or light, generating carbon radicals, which cause molecular scission, resulting in a decrease in mechanical properties and browning.

[0003] Among polymer materials, fluororesins such as polytetrafluoroethylene (PTFE) are materials that have excellent heat resistance and UV resistance. However, since harmful perfluorooctanoic acid (PFOA) is produced as a by-product during the production of PTFE, there are concerns about restrictions on the production of fluororesins.

[0004] In addition, aromatic polyimides, known as super engineering plastics, are known as high-performance polymer materials. Although aromatic polyimides exhibit high thermal stability and mechanical strength, they have issues with light transparency and UV resistance due to coloring derived from the aromatic rings.

[0005] On the other hand, polydimethylsiloxane (PDMS) is known as a polymeric material with high heat and UV resistance, and is used in the electrical and electronics and automotive industries due to its flexibility in addition to its high stability against heat and light derived from siloxane bonds. However, because of its flexibility, it is difficult to use PDMS as a hard coating agent. It is also expected to be used as an encapsulant for LEDs, but there are issues with its high thermal expansion coefficient and low gas barrier properties, such as breakage due to expansion and deterioration of semiconductor light-emitting elements due to water vapor transmission.

[0006] In light of these issues with polymer materials, high-performance polymer materials that exhibit heat resistance, UV resistance, transparency, hard coat properties, low thermal expansion, gas barrier properties, and safety, and also possess solubility, a characteristic of polymer materials that is not found in purely inorganic materials such as ceramics and glass, are expected to be used as materials to support smartphones, self-driving cars, drones, and other products that will be created using ICT technologies such as IoT, AI, 5G, and big data.

[0007] Polysiloxanes with ladder-like structures that do not contain aromatic rings are expected to be polymeric materials that combine all of the above characteristics. Non-Patent Documents 1 and 2 discuss the synthesis of ladder-like polymethylsilsesquioxanes (PMSQs) by synthesizing a cyclic tetrasiloxane precursor with a reactive group in advance and then subjecting it to a condensation reaction. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] "cis-trans-cis-Tetrabromotetramethylcyclotetrasiloxane: a Versatile Precursor of Ladder Silsesquioxanes", M. Unno et al., Bull. Chem. Soc. Jpn., 2005, 78, 1105-1109. [Non-Patent Document 2] "Synthesis and structure of ladder polymethylsilsesquioxanes from sila-functionalized cyclotetrasiloxanes", H. Seki et al., Journal of Organometallic Chemistry 695 (2010) 1363-1369. Summary of the Invention [Problem to be solved by the invention]

[0009] In Non-Patent Documents 1 and 2, the synthesis of PMSQ requires the synthesis of a cyclic tetrasiloxane precursor, which requires complicated multi-step reactions. Considering the application to various fields, a method that allows for easy synthesis is desired.

[0010] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a ladder-like polysiloxane that can be easily synthesized and a method for producing the same. [Means for solving the problem]

[0011] The ladder-like polysiloxane according to the first aspect of the present invention comprises: Having a structure represented by formula 1: [ka] (In formula 1, R 1 each independently represents an alkyl group having 1 to 3 carbon atoms; R 2 each independently represents an alkyl group having 1 to 3 carbon atoms, Z represents an alkylene chain having 2 to 4 carbon atoms, and n represents a positive real number. It is characterized by:

[0012] The ladder-like polysiloxane according to the second aspect of the present invention comprises: Having a structure represented by formula 2: [ka] (In formula 2, R 1 each independently represents an alkyl group having 1 to 3 carbon atoms; R 2 each independently represents an alkyl group having 1 to 3 carbon atoms; R 3 each independently represents an alkyl group having 1 to 3 carbon atoms, Z represents an alkylene chain having 2 to 4 carbon atoms, and n represents a positive real number. It is characterized by:

[0013] A method for producing a ladder-like polysiloxane according to a third aspect of the present invention comprises the steps of: A compound represented by formula 11 is reacted with a compound represented by formula 12 to synthesize a compound represented by formula 13; [ka] (In formula 11 and formula 13, R 1 each independently represents an alkyl group having 1 to 3 carbon atoms, m represents an integer of 0 to 2, and n represents a positive real number. In formulas 12 and 13, R 2 each independently represents an alkyl group having 1 to 3 carbon atoms, and in formula 13, Z represents an alkylene chain having 2 to 4 carbon atoms. A compound represented by formula 13 is subjected to intramolecular polycondensation to synthesize a ladder-shaped polysiloxane having a structure represented by formula 1. [ka] (In formula 1, R 1 each independently represents an alkyl group having 1 to 3 carbon atoms; R 2 each independently represents an alkyl group having 1 to 3 carbon atoms, Z represents an alkylene chain having 2 to 4 carbon atoms, and n represents a positive real number. It is characterized by:

[0014] A method for producing a ladder-like polysiloxane according to a fourth aspect of the present invention comprises the steps of: A ladder-shaped polysiloxane having a structure represented by formula 1 is reacted with a compound represented by formula 14 to protect the terminal silanol groups of the ladder-shaped polysiloxane represented by formula 1, thereby synthesizing a ladder-shaped polysiloxane having a structure represented by formula 2; [ka] (In formula 1 and formula 2, R1 each independently represents an alkyl group having 1 to 3 carbon atoms, Z represents an alkylene chain having 2 to 4 carbon atoms, and n represents a positive real number. In formula 14 and formula 2, R 3 each independently represents an alkyl group having 1 to 3 carbon atoms, and in formula 14, X represents a halogen. It is characterized by: Effect of the Invention

[0015] According to the present invention, it is possible to provide a ladder-like polysiloxane that can be easily synthesized and a method for producing the same. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 shows the results of 29Si-NMR measurement of PMVS. [Diagram 2] FIG. 1 shows the results of GPC measurement of PMVS. [Diagram 3] FIG. 1 shows the results of GPC measurement of ECL-LPS*. [Figure 4] FIG. 1 shows the results of GPC measurement of ECL-LPS. [Diagram 5] FIG. 1 shows the results of 1H-NMR measurement of ECL-LPS*. [Figure 6] FIG. 1 shows the results of 1H-NMR measurement of ECL-LPS. [Figure 7] FIG. 1 shows the results of 29Si-NMR measurement of ECL-LPS*. [Figure 8] FIG. 1 shows the results of 29Si-NMR measurement of ECL-LPS. [Figure 9] FIG. 1 shows the results of DSC measurement. [Figure 10] FIG. 1 shows the results of TGA measurement. [Figure 11] FIG. 1 shows the results of UV-Vis measurement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The ladder-like polysiloxane according to the present embodiment has a structure represented by Formula 1 or Formula 2.

[0018] [ka]

[0019] In formula 1 and formula 2, R 1each independently represents an alkyl group having 1 to 3 carbon atoms; R 2 each independently represents an alkyl group having 1 to 3 carbon atoms, Z represents an alkylene chain having 2 to 4 carbon atoms, and n represents a positive real number. 3 each independently represents an alkyl group having 1 to 3 carbon atoms.

[0020] From the viewpoint of heat resistance, etc., in Formula 1 and Formula 2, R 1 ~R 3 The alkyl group represented by the formula (I) preferably has a smaller number of carbon atoms, and is preferably a methyl group.

[0021] In addition, in terms of heat resistance and the like, the alkylene chain represented by Z in formula 1 preferably has a smaller number of carbon atoms, and is preferably an ethylene chain.

[0022] The ladder-shaped polysiloxanes represented by Formula 1 and Formula 2 have thermal, mechanical, and chemical stability derived from the Si-O-Si bond. Since the ladder-shaped polysiloxanes represented by Formula 1 and Formula 2 have a double-chain main chain, conformational changes are more limited than in the case of a single-chain main chain, and therefore the ladder-shaped polysiloxanes have high rigidity.

[0023] In addition, as shown in the examples below, ladder-type polysiloxanes have a thermal decomposition temperature of over 500°C and are excellent in heat resistance. In addition, as shown in the examples below, ladder-type polysiloxanes have high light transmittance and excellent UV resistance. Furthermore, ladder-type polysiloxanes are superior in solubility in various solvents compared to random polysiloxanes.

[0024] Thus, the ladder-like polysiloxanes represented by Formula 1 and Formula 2 have high levels of heat resistance, UV resistance, solubility, rigidity, flexibility, low thermal expansion, gas barrier properties, safety, etc. Therefore, they are expected to be applied in various fields as high-performance polymer materials, including coating agents and sealants for LEDs, etc.

[0025] (Method for producing ladder-shaped polysiloxane) The ladder-shaped polysiloxane represented by formula 1 can be synthesized, for example, as follows, and more specifically, as shown in the examples described later.

[0026] Polyvinylsiloxane represented by formula 11 and having vinyl groups on the side chains is reacted with dialkoxysilane represented by formula 12. By the hydrosilylation reaction, polysiloxane represented by formula 13 having dialkoxysilyl groups introduced on the side chains is obtained.

[0027] [ka]

[0028] In formula 11 and formula 13, R 1 each independently represents an alkyl group having 1 to 3 carbon atoms, m represents an integer of 0 to 2, and n represents a positive real number. 2 each independently represents an alkyl group having 1 to 3 carbon atoms. In addition, in formula 13, Z represents an alkylene chain having 2 to 4 carbon atoms.

[0029] The compound represented by formula 11 can be synthesized and used with reference to K. Fuchise, K. Sato, S. Shimada et al., Chem. Sci., 2018, 9, 2879.

[0030] Next, the polysiloxane represented by formula 13 is subjected to intramolecular polycondensation to form an alkoxysilyl group (R 2 O-Si(R 2 )-OR 2 ) are bonded to each other to obtain the ladder-shaped polysiloxane represented by formula 1.

[0031] The ladder-shaped polysiloxane represented by formula 2 can be obtained by protecting the terminal silanol group of the main chain of the ladder-shaped polysiloxane represented by formula 1. Specifically, this can be achieved by reacting the ladder-shaped polysiloxane represented by formula 1 with a compound represented by formula 14. In formula 14, X represents a halogen such as chlorine or bromine; 3 represents an alkyl group having 1 to 3 carbon atoms.

[0032] [ka]

[0033] In the present embodiment, there is no need to synthesize a cyclic tetrasiloxane precursor, which requires complicated multi-step reactions to synthesize PMSQ, as in Non-Patent Documents 1 and 2. Therefore, the present invention can be applied to the industrial production of ladder-shaped polysiloxanes. EXAMPLES

[0034] (Synthesis of ladder-shaped polymethylsiloxane) The ladder-shaped polysiloxane (ECL-LPS) was prepared as follows: * ) and ladder-shaped polysiloxane with terminal silanol groups protected (hereinafter, ECL-LPS) were synthesized in a stepwise manner.

[0035] (Synthesis of polymethylvinylsiloxane (PMVS)) PMVS was synthesized as shown in the scheme below, with reference to K. Fuchise, K. Sato, S. Shimada et al., Chem. Sci., 2018, 9, 2879.

[0036] [ka]

[0037] Specifically, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane (50.0 mmol, 13.605 g) was dissolved in a mixed solvent of dichloromethane (16 mL) and THF (tetrahydrofuran) (12 mL), and generated water (5.0 mmol, 90 μL) and TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene) (0.5 mmol, 0.071 g) were added as catalysts, followed by stirring at 30° C. for 3 hours. The resulting mixture was neutralized with benzoic acid, and then washed with acetonitrile to obtain polyvinylmethylsiloxane (PVMS-(OH)2) with silanol groups at the ends of the main chain. To protect the silanol groups at the ends of the main chain of PVMS-(OH)2, pyridine (40.0 mmol, 3.064 g) and chlorotrimethylsilane (25.0 mmol, 3.4298 g) were added and stirred at 30°C for 20 minutes. After that, the mixture was washed with acetonitrile, dissolved in diethyl ether, filtered by suction, and the soluble portion was dried under reduced pressure to obtain PMVS.

[0038] Regarding the synthesized PMVS, 29 Si-NMR and GPC (Gel Permeation Chromatography) measurements were carried out. 29 The results of Si-NMR and GPC are shown in Figure 1 and Figure 2, respectively. 29 The results of Si-NMR confirmed that a homopolymer with almost no impurities was obtained. 2 The ratio of the structure to the M structure is D 2 The weight average molecular weight (M w ) is 9.56 × 10 3 , number average molecular weight (M n ) is 7.48 × 10 3 The degree of polymerization was about 109. 2 Judging from the ratio of the structure to the M structure and the degree of polymerization, it can be said that the terminal protection of the obtained PMVS has progressed to almost 100%.

[0039] (ECL-LPS * Synthesis of As shown in the following scheme, ECL-LPS * was synthesized.

[0040] [ka]

[0041] To PMVS (1.64 mmol unit, 0.1434 g), 1.05 equivalents of diethoxymethylsilane (DEMS) (1.72 mmol, 0.2431 g) was dissolved in dehydrated xylene (1.5 mL) and added. In addition, the Karstedt catalyst was added to the functional groups of PMVS in the amount of 6.56 × 10 Pt. -2 The mixture was added in mmol (as a mixture of 0.0638 g of Karstedt catalyst (Pt content: approximately 20% by weight) and 1.7144 g of xylene) and stirred at 30° C. for 12 hours under an argon atmosphere. Then, activated carbon (0.0172 g) was added and the mixture was stirred for 1 hour at about 4° C. Then, the platinum catalyst and activated carbon were removed by suction filtration to obtain a PS-DES solution having dialkoxysilyl groups in its side chains as the product. Subsequently, the obtained PS-DES solution was added dropwise to a mixed solvent of toluene and DMF (1 L, toluene and DMF volume ratio of 3:2) to dilute it. Furthermore, concentrated hydrochloric acid (3.28 mmol, 278 μL) as a catalyst and purified water (318 μL) were added to this diluted solution, and then a reflux condenser was attached and the mixture was stirred at 120° C. for 72 hours. The reaction solution was then concentrated to approximately 15 mL at 80° C. using a rotary evaporator, and then reprecipitated by dropping into 350 mL of water. After suction filtration and freeze-drying, a light brown powder was obtained. The crude product was then added to 80 mL of methanol, stirred at room temperature for 1 hour, and suction filtered to recover the soluble portion. The soluble portion was concentrated to approximately 15 mL using a rotary evaporator, and reprecipitated by dropping again into 350 mL of water. Then, suction filtration and freeze-drying were performed to obtain a light brown powder. The resulting powder was then added to 30 mL of hexane and stirred at room temperature for 1 hour, after which it was suction filtered and dried under reduced pressure to obtain a light brown powder as the final product.

[0042] (Synthesis of ECL-LPS) As shown in the following scheme, ECL-LPS * The remaining silanol groups were treated to synthesize ECL-LPS.

[0043] [ka]

[0044] ECL-LPS * (0.6 mmol unit, 0.0977 g) was dissolved in chloroform (2.0 mL), and trimethylchlorosilane (4.8 mmol, 0.6585 g) and pyridine (7.8 mmol, 0.62 g) each dissolved in chloroform 2 ml were added thereto, followed by stirring at 30° C. for 40 minutes. Reprecipitation was carried out using acetonitrile (180 mL) to obtain ECL-LPS with protected silanol groups.

[0045] Synthesized ECL-LPS * The following verifications were carried out for ECL-LPS.

[0046] (Verification of solubility in various solvents) Synthesized ECL-LPS * ECL-LPS was added to various solvents (water, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), methanol, ethanol, 1-propanol, 1-butanol, acetone, methyl isobutyl ketone (MIBK), diisobutyl ketone (DIBK), tetrahydrofuran (THF), chloroform, ethyl acetate, diethyl ether, diglyme, toluene, and hexane) to examine its solubility in various solvents. * The solubility results for ECL-LPS and ECL-LPS are shown in Tables 1 and 2.

[0047] [Table 1]

[0048] [Table 2]

[0049] ECL-LPS with unprotected silanol groups * was soluble in a wide range of solvents, from polar solvents such as ethanol and acetone to non-polar solvents such as chloroform and diethyl ether, but was insoluble in highly polar solvents such as water and DMSO, and in hexane.

[0050] Furthermore, ECL-LPS with protected silanol groups was insoluble in ethanol and acetone, but was soluble in hexane, indicating a difference in solubility before and after protection of the silanol groups.

[0051] (GPC measurement) The standard substance was polystyrene and the eluent was THF. * GPC measurements were performed on ECL-LPS. * The results of GPC measurement of ECL-LPS and ECL-LPS are shown in Figures 3 and 4, respectively.

[0052] ECL-LPS * Weight average molecular weight (M w ) is 1.75 × 10 4 , number average molecular weight (M n ) is 1.03 × 10 4 indicates M w / M n The weight average molecular weight (M) of ECL-LPS was 1.70. The degree of polymerization was 118. It was suggested that the dialkoxysilyl in the side chain of PS-DES was almost completely condensed to form a siloxane bond. w ) is 1.69 × 10 4 , number average molecular weight (M n ) is 1.06 × 10 4 indicates M w / M n The molecular weight was 1.59, and the degree of polymerization was 114.

[0053] (1 H-NMR measurement, 29 Si-NMR measurement) ECL-LPS * and ECL-LPS, 1 H-NMR measurements and 29 Si-NMR measurements were performed. ECL-LPS * and ECL-LPS 1 The H-NMR measurement results are shown in Figures 5 and 6. 29 The results of the Si-NMR measurements are shown in Figures 7 and 8, respectively.

[0054] 1 From the H-NMR measurement results, * The ratio of the alkyl chains added by the hydrosilylation reaction during synthesis was 70% at the β-position and 30% at the α-position. * It was confirmed that the signal derived from silanol observed at around 3.64 ppm disappeared due to protection of the silanol group during the synthesis of ECL-LPS.

[0055] 29 The integrated intensity ratio of the signal assigned to the Si atom obtained from the Si-NMR measurement results is * Well then, M:(D 2 ) C3 :D 1 :D 2 In ECL-LPS, the M:(D 2 ) C3 :D 1 :D 2 The ratio was 15:3:0:82. Therefore, ECL-LPS * In ECL-LPS, most of the Si atoms are D 2 It forms a structure.

[0056] In addition, since it is soluble in various solvents, it can be said that it has a one-dimensional structure, not a random type. Based on these results, the obtained ECL-LPS can be said to be a polysiloxane with a ladder structure as shown in the following formula.

[0057] [ka]

[0058] (DSC (Differential Scanning Calorimetry) measurement) ECL-LPS * DSC and TG measurements were carried out on the above sample, and the results are shown in Figure 9. DSC measurements showed that PMVS had a glass transition temperature of -79°C and a melting point of -28°C, whereas ECL-LPS * The glass transition temperature was 80°C and the melting point was 189°C.

[0059] (TGA (Thermogravimetric Analysis) measurement) Powdered ECL-LPS * , ECL-LPS (here, ECL-LPS * (powder) and ECL-LPS (powder). * (Powder) was dissolved in a solvent to form a film, and then heat-treated at 300°C for 3 hours to obtain a cast film (ECL-LPS * TGA measurements were also performed on the aromatic polyimide (film) and a cast film (aromatic polyimide (film)) obtained by dissolving the aromatic polyimide in a solvent, forming a film, and then heat-treating the film at 360°C for 3 hours.

[0060] The results of the TGA measurement are shown in Figure 10. ECL-LPS * (powder) 10% thermogravimetric reduction temperature (T d10 ) was 528°C. The T d10 The result was 520℃. ECL-LPS * Both ECL-LPS (powder) and ECL-LPS (powder) exceeded 500°C, demonstrating their excellent thermal stability. Note that differences in weight loss at low temperatures and final residues can be seen depending on whether the silanol groups are protected or unprotected, so the unprotected ECL-LPS *It is believed that self-condensation of silanol groups occurs in ECL-LPS. * In the case of (membrane), cracks occurred in the membrane itself, but T d10 showed extremely high thermal stability of 761°C, which was higher than that of aromatic polyimide (film).

[0061] (UV-Vis (Ultraviolet-Visible Absorption Spectroscopy) measurement) ECL-LPS * and ECL-LPS were dissolved in diisobutyl ketone (DIBK) (0.5 mg / 0.1 mL), and the solution was dropped onto a quartz glass substrate. The solvent was removed at 50°C to obtain ECL-LPS. * The membrane and ECL-LPS membrane were prepared. * Both the membrane and the ECL-LPS membrane were colorless and transparent.

[0062] ECL-LPS * UV-Vis measurements were also performed on a silicone film formed on a quartz glass substrate and an aromatic polyimide film formed on a glass substrate for comparison.

[0063] The results are shown in Figure 11. ECL-LPS * Both the ECL-LPS and ECL-LPS films showed a transmittance of over 90% in the visible light region of 380 to 800 nm, and also showed high transmittance in the ultraviolet region of 380 to 200 nm. This suggests that the ECL-LPS thin film has a very high light transmittance and excellent UV resistance compared to aromatic polyimide, a high-performance polymer material. [Industrial Applicability]

[0064] Ladder-type polysiloxanes can be used as high-performance polymer materials in a variety of fields, including as coating agents and sealants for LEDs.

Claims

1. Having a structure represented by formula 1: 【Chemistry 1】 (In formula 1, R １ each independently represents an alkyl group having 1 to 3 carbon atoms; R ２ each independently represents an alkyl group having 1 to 3 carbon atoms, Z represents an alkylene chain having 2 to 4 carbon atoms, and n represents a positive real number.

1. A ladder-like polysiloxane comprising:

2. Having a structure represented by formula 2: 【Chemistry 2】 (In formula 2, R １ each independently represents an alkyl group having 1 to 3 carbon atoms; R ２ each independently represents an alkyl group having 1 to 3 carbon atoms; R ３ each independently represents an alkyl group having 1 to 3 carbon atoms, Z represents an alkylene chain having 2 to 4 carbon atoms, and n represents a positive real number.

1. A ladder-like polysiloxane comprising:

3. reacting a compound represented by formula 11 with a compound represented by formula 12 to synthesize a compound represented by formula 13; 【Chemistry 3】 (In Formula 11 and Formula 13, R １ each independently represents an alkyl group having 1 to 3 carbon atoms, m represents an integer of 0 to 2, and n represents a positive real number. In formulas 12 and 13, R ２ each independently represents an alkyl group having 1 to 3 carbon atoms, and in formula 13, Z represents an alkylene chain having 2 to 4 carbon atoms. The compound represented by formula 13 is subjected to intramolecular condensation polymerization to synthesize a ladder-shaped polysiloxane having a structure represented by formula 1. 【Chemistry 4】 (In formula 1, R １ each independently represents an alkyl group having 1 to 3 carbon atoms; R ２ each independently represents an alkyl group having 1 to 3 carbon atoms, Z represents an alkylene chain having 2 to 4 carbon atoms, and n represents a positive real number.

1. A method for producing a ladder-like polysiloxane comprising the steps of:

4. A ladder-like polysiloxane having a structure represented by formula 1 is reacted with a compound represented by formula 14 to protect the terminal silanol groups of the ladder-like polysiloxane represented by formula 1, thereby synthesizing a ladder-like polysiloxane having a structure represented by formula 2; 【Chemistry 5】 (In Formula 1 and Formula 2, R １ each independently represents an alkyl group having 1 to 3 carbon atoms, Z represents an alkylene chain having 2 to 4 carbon atoms, and n represents a positive real number. In Formula 14 and Formula 2, R ３ each independently represents an alkyl group having 1 to 3 carbon atoms, and in formula 14, X represents a halogen.

1. A method for producing a ladder-like polysiloxane comprising the steps of:

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