Polysiloxane composition, adhesive, and method for producing polysiloxane composition

Abstract

To provide an adhesive that can achieve bonding with high thermostability, a polysiloxane composition that is usable as a component of the adhesive, and a method for producing the polysiloxane composition.SOLUTION: A polysiloxane composition has a main chain, and a catechol group as a side chain bound to the main chain. The main chain comprises a repeat of a cage-like constitutional unit comprising polyhedron oligosilsesquioxane and an open-chain constitutional unit comprising a siloxane chain, with adjacent cage-like constitutional units being linked via the open-chain constitutional unit. The catechol group binds to each of the cage-like constitutional units constituting the main chain.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a polysiloxane composition, an adhesive, and a method for making a polysiloxane composition. [Background technology]

[0002] In recent years, proteins with adhesive properties secreted by marine organisms such as mussels have been attracting attention. It has been revealed that the catechol group contained in the protein contributes to the expression of adhesive properties. In addition, the application of catechol groups to adhesives has been studied (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2005 / 056708 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide an adhesive capable of achieving adhesion with excellent heat resistance, a polysiloxane composition that can be used as a component of the adhesive, and a method for producing the polysiloxane composition. [Means for solving the problem]

[0005] The polysiloxane composition according to the present invention comprises: a main chain having a structure in which a cage structural unit made of a polyhedral oligosilsesquioxane and a chain structural unit having a siloxane chain are repeated, the cage structural unit being adjacent to each other and connected to the chain structural unit; a catechol group bonded to each of the cage structural units constituting the main chain; and has.

[0006] The siloxane chain has a structure in which siloxane units, which are D units, are linked in a linear chain, The degree of polymerization of the siloxane units in the siloxane chain may be 30 or less.

[0007] In the polysiloxane composition, a molar ratio of the polyhedral oligosilsesquioxane to the siloxane chain may be 1 / 3 or more and 1 or less.

[0008] The catechol group may be bonded to the polyhedral oligosilsesquioxane via a urea linkage structure.

[0009] The chain structural unit may have urea bonds arranged at both ends of the siloxane chain.

[0010] The adhesive according to the present invention contains the above-mentioned polysiloxane composition according to the present invention.

[0011] The method for producing the polysiloxane composition according to the present invention comprises the steps of: a precursor polysiloxane composition producing step of producing a precursor polysiloxane composition which is a copolymer of a cage-like structural unit composed of a polyhedral oligosilsesquioxane having a substituent containing a urea group and a chain-like structural unit having a siloxane chain; a catechol group introduction step of reacting the precursor polysiloxane composition with a catecholamine to introduce a catechol group into the substituent via a urea bond containing the urea group; Includes.

[0012] Prior to the step of producing the precursor polysiloxane composition, a precursor cage structure unit preparation step of preparing a precursor cage structure unit composed of a polyhedral oligosilsesquioxane having a compound containing an ammonium group as a substituent; a urea group forming step of reacting the precursor cage structural unit with a carbonyl compound to replace the compound containing the ammonium group in the substituent of the precursor cage structural unit with the compound containing the urea group; It may further include.

[0013] the chain structural unit used to generate the precursor polysiloxane composition in the precursor polysiloxane composition generating step has amino groups arranged at both ends of the siloxane chain, In the catechol group introduction step, the amino group may be replaced with a urea bond by a reaction between the precursor polysiloxane composition and the catecholamine. Effect of the Invention

[0014] The adhesive according to the present invention can achieve adhesion with excellent heat resistance. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a conceptual diagram showing the global structure of a polysiloxane composition according to an embodiment. [Diagram 2] 1 is a flowchart showing a method for producing a polysiloxane composition according to an embodiment. [Diagram 3] FIG. 2 is a conceptual diagram showing a part of the production process of the polysiloxane compositions according to Examples 1 to 6. [Figure 4] FIG. 4 is a conceptual diagram showing the remaining steps of the production process for the polysiloxane compositions of Examples 1-6. [Diagram 5] 1 is a graph showing the Fourier transform infrared spectroscopy (FT-IR) spectrum of the polysiloxane composition according to Examples 1-6. [Figure 6] Graph showing proton nuclear magnetic resonance ( 1 H-NMR) spectra of the polysiloxane compositions according to Examples 1-4. [Figure 7] FIG. 1 is a conceptual diagram showing a procedure for producing an evaluation sample. [Figure 8](a): Photograph showing the results of a heat resistance test on a sample for evaluating like-material adhesion according to Example 1; (b): Photograph showing the results of a heat resistance test on a sample for evaluating like-material adhesion according to Example 2; (c): Photograph showing the results of a heat resistance test on a sample for evaluating like-material adhesion according to Example 3; (d): Photograph showing the results of a heat resistance test on a sample for evaluating like-material adhesion according to Example 4; (e): Photograph showing the results of a heat resistance test on a sample for evaluating like-material adhesion according to Example 5; (f): Photograph showing the results of a heat resistance test on a sample for evaluating like-material adhesion according to Example 6. [Figure 9] (a): Photograph showing the results of a heat resistance test of a sample for evaluating adhesion of dissimilar materials according to Example 1; (b): Photograph showing the results of a heat resistance test of a sample for evaluating adhesion of dissimilar materials according to Example 3; (c): Photograph showing the results of a heat resistance test of a sample for evaluating adhesion of dissimilar materials according to commercially available Reference Example 1; (d): Photograph showing the results of a heat resistance test of a sample for evaluating adhesion of dissimilar materials according to commercially available Reference Example 2. [Figure 10] FIG. 1 is a stress-strain curve of the sample for evaluating homogeneous material adhesion according to Examples 1-6. [Figure 11] FIG. 13 is a stress-strain curve showing the results when the area of ​​the adhesive surface is reduced for the samples for evaluating adhesion of the same materials according to Examples 1-6 and commercially available Reference Examples 1-9. [Figure 12] 1 is a stress-strain diagram of the sample for evaluating homogeneous material adhesion according to Example 1-3 after being immersed in water for two days. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, a polysiloxane composition according to an embodiment will be described as one specific example of the polysiloxane composition according to the present invention described above.

[0017] The global chemical structure of the polysiloxane composition according to this embodiment is shown in Figure 1. The polysiloxane composition according to this embodiment has a structure in which a plurality of catechol groups are bonded as side chains to a main chain.

[0018] The main chain is made of a copolymer in which a cage structural unit made of polyhedral oligomeric silsesquioxane (POSS) and a chain structural unit having a siloxane chain are repeatedly arranged. The main chain is linear as a whole, and has a structure in which adjacent cage structural units are linked by a chain structural unit.

[0019] Polyhedral oligosilsesquioxane has a polyhedral skeleton structure in which siloxane T units are linked in a three-dimensional lattice. Although a hexahedral skeleton structure consisting of eight T units is illustrated in FIG. 1, the skeleton structure is not limited to a hexahedron as long as it is a polyhedron. Polyhedral oligosilsesquioxane has a rigidity that stably maintains the polyhedral skeleton structure even when the cured product of the polysiloxane composition is heated.

[0020] The catechol groups are bonded to each of the polyhedral oligosilsesquioxanes arranged in a discrete and repeated manner along the length of the main chain, and constitute side chains to the main chain. The catechol groups mainly contribute to the development of strong adhesive properties of the polysiloxane composition.

[0021] The siloxane chain is a polymer in which D units having an organic substituent, i.e., diorganosiloxane units, are repeatedly arranged in a linear chain. In Fig. 1, a methyl group is shown as an example of the organic substituent, but the organic substituent is not limited to this. As the organic substituent, for example, one having 10 or less carbon atoms, specifically, an alkyl group having 10 or less carbon atoms, can be used.

[0022] The siloxane chain has flexibility capable of absorbing thermal distortion when the cured body of the polysiloxane composition is heated. However, if this flexibility is excessive, the cured body of the polysiloxane composition is likely to soften. Therefore, in order to impart an appropriate flexibility to the siloxane chain, the degree of polymerization of the diorganosiloxane unit in the siloxane chain (hereinafter, represented by a natural number N) is preferably 31 or less, more preferably 20 or less, more preferably 15 or less, more preferably 10 or less, more preferably 8 or less, and more preferably 5 or less, with 2 as the lower limit.

[0023] In Figure 1, the degree of polymerization of the central portion of the siloxane chain, excluding the organosilicon compounds at both ends, is denoted as n. Since the organosilicon compound at one end of the siloxane chain corresponds to a diorganosiloxane unit, the degree of polymerization N of the diorganosiloxane unit for the entire siloxane chain is given by N = n + 1.

[0024] In order to achieve a good balance between the rigidity of the polyhedral oligosilsesquiosane and the flexibility of the siloxane chain as described above and to further improve heat resistance, the molar ratio of polyhedral oligosilsesquiosane / siloxane chain in the polysiloxane composition is preferably 1 / 3 or more and 1 or less.

[0025] Next, a method for producing the polysiloxane composition according to this embodiment will be described.

[0026] First, a precursor polysiloxane composition, which is a precursor of the polysiloxane composition according to the present embodiment, is produced. Next, a catechol group is introduced into the side chain of the precursor polysiloxane composition to obtain the polysiloxane composition according to the present embodiment.

[0027] According to the research of the present inventors, the introduction of catechol groups is particularly efficient when carried out via a urea bond structure. In other words, in order to increase the introduction rate of catechol groups, it is desirable to use a urea bond structure. Hereinafter, a method for producing a polysiloxane composition in which catechol groups are introduced using a urea bond structure will be specifically described.

[0028] As shown in FIG. 2, first, a precursor of a cage structural unit (hereinafter referred to as a precursor cage structural unit) made of a polyhedral oligosilsesquioxane having a compound containing an ammonium group as a substituent is prepared (precursor cage structural unit preparation step S1).

[0029] Next, the precursor cage structural unit is reacted with a carbonyl compound to replace the compound containing an ammonium group in the substituent of the precursor cage structural unit with a compound containing a urea group (urea group forming step S2).

[0030] This results in a cage-shaped structural unit made of a polyhedral oligosilsesquioxane having a substituent containing a urea group. In this specification, the urea group refers to a group represented by -NH-CO-N= or a group represented by -NH-CO-N<.

[0031] Next, a precursor polysiloxane composition is produced, which is a copolymer of a cage structural unit made of the polyhedral oligosilsesquioxane having a substituent containing a urea group and a chain structural unit having a siloxane chain (precursor polysiloxane composition production step S3).

[0032] Next, the precursor polysiloxane composition is reacted with a catecholamine to introduce a catechol group into the substituent of the cage structural unit via a urea bond containing a urea group (catechol group introduction step S4).

[0033] As described above, the introduction rate of the catechol group can be increased by passing the urea bond through the urea bond, and thus the polysiloxane composition according to the present embodiment can be obtained, in which the substituent of the cage structural unit has a urea bond and a catechol group bonded to the urea bond.

[0034] The resulting polysiloxane composition can be used as a component of an adhesive, specifically as a main component. Here, "main component" means a content of more than 50 wt%, and is a concept that includes 100 wt%. EXAMPLES

[0035] An embodiment of the manufacturing method shown in FIG. 2 will be described below with reference to FIGS.

[0036] As shown in Figure 3, first, a polyhedral oligosilsesquioxane with eight vertices and NH3OTf as a substituent was prepared (hereinafter, referred to as Am-T8-POSS). Am-T8-POSS was synthesized by hydrolysis and condensation reaction of amino-group-containing organic trialkoxysilane using an aqueous solution of trifluoromethanesulfonic acid (HOTf), which is a superacid, as a catalyst and solvent, according to the following literature [1]. [1] Y. Kaneko et al., Inorg. Chem., 2017, 56, 4133-4140

[0037] This step is an example of the precursor cage structure unit preparation step S1 shown in Fig. 2. That is, Am-T8-POSS is an example of the precursor cage structure unit described above, and NH3OTf contained in the substituent is an example of the compound containing the ammonium group described above.

[0038] Next, 6.0 mL of dehydrated DMF was added to Am-T8-POSS (6.0 mmol unit, 1.5616 g) to dissolve it, and 3.0 mL of dehydrated DMF (N,N-dimethylformamide) was added to triethylamine [(MW = 101.19 g / mol, purity: 99%): 18 mmol = 1.8398 g] to dissolve it, and 12.0 mL of dehydrated DMF was added to 1,1'-carbonyldiimidazole [(MW = 162.15 g / mol, purity: 97%): 12 mmol = 2.0060 g] to dissolve it, and the obtained DMF solutions of Am-T8-POSS, triethylamine, and 1,1'-carbonyldiimidazole were mixed. The mixture was then stirred at room temperature for 15 minutes, and the reaction solution was then poured into 630 mL of ethyl acetate. The precipitated product was recovered by decantation and dried under reduced pressure to obtain a polyhedral oligosilsesquioxane (hereinafter referred to as POSS-CIm) having a structure in which imidazole is linked to an amide bond as a substituent.

[0039] This step is an example of the urea group forming step S2 shown in Fig. 2. The 1,1'-carbonyldiimidazole used in this step is an example of the carbonyl compound already described. Also, the structure shown in Fig. 3 in which imidazole is linked to an amide bond is an example of a compound containing the urea group -NH-CO-N< as a whole.

[0040] On the other hand, two types of specific examples of chain structural units having siloxane chains were prepared.

[0041] The first chain structural unit is an oligodimethylsiloxane modified with amines at both ends (hereinafter referred to as ODMS-AP). ODMS-AP was obtained by mixing 1,1,3,3,5,5,7,7,9,9,11,11-dodecamethylhexasiloxane [(MW=430.94g / mol, purity: 96%): 1mmol=0.4489g] with allylamine [(MW=57.09g / mol, purity: 98%): 2mmol=0.1165g], adding platinum catalyst [Platinum(0)-1,3-Divinyltetramethyldisiloxane Complex (19.0-21.5% as Pt) (contains 1,3-Divinyltetramethyldisiloxane), 0.25mol%, 4.1μL], and heating and stirring at 80℃ for 6 hours under an Ar atmosphere.

[0042] The second chain structural unit is polydimethylsiloxane modified with amines at both ends (hereinafter, referred to as PDMS-AP). A commercially available PDMS-AP was used.

[0043] The general structural formulas of ODMS-AP and PDMS-AP are shown in Figure 3. As shown in Figure 3, both ODMS-AP and PDMS-AP have a linear siloxane chain and aminopropyl as amino groups arranged at both ends of the siloxane chain.

[0044] In Fig. 3, the degree of polymerization of the central part of the siloxane chain excluding the silicon compounds at both ends (hereinafter referred to as the degree of polymerization of the main part) is represented as n. The degree of polymerization of the main part of ODMS-AP is 4. On the other hand, the degree of polymerization of the main part of PDMS-AP is about 30.

[0045] Next, 3.0mL of dehydrated THF (tetrahydrofuran) was added to ODMS-AP (0.15mmol, 0.0818g) which is the first chain structure unit to dissolve it, and 3.0mL of dehydrated DMF was added to POSS-CIm (0.15mmol, 0.2451g) to dissolve it, and the obtained THF solution of ODMS-AP and DMF solution of POSS-CIm were mixed, and then stirred at room temperature for 1 hour under Ar atmosphere to obtain a precursor polysiloxane composition (hereinafter referred to as POSS-CIm-ODMS). Note that this process is an example of the precursor polysiloxane composition generation process S3 shown in FIG. 2.

[0046] Similarly, 6.0mL of dehydrated THF was added to PDMS-AP (0.15mmol, 0.3750g), which is the second chain structural unit, to dissolve it, and 3.0mL of dehydrated DMF was added to POSS-CIm (0.15mmol, 0.2451g) to dissolve it, and the obtained THF solution of PDMS-AP and DMF solution of POSS-CIm were mixed, and then stirred at room temperature for 1 hour under an Ar atmosphere to obtain a precursor polysiloxane composition (hereinafter referred to as POSS-CIm-PDMS). Note that this process is also an example of the precursor polysiloxane composition generation process S3 shown in FIG. 2.

[0047] The explanation will be continued with reference to FIG. 4. 1.2 mL of dehydrated DMF was added to 3-hydroxytyramine hydrochloride (dopamine hydrochloride) [(MW=189.64 g / mol, purity: 98%): 1.8 mmol=0.3483 g] to dissolve it, and 1.2 mL of dehydrated DMF was added to triethylamine [(MW=101.19 g / mol, purity: 99%): 3.6 mmol=0.3680 g] to dissolve it, and the obtained solutions were mixed. The mixed solution was added to the reaction solution of POSS-CIm-ODMS prepared above, and heated and stirred at about 50° C. for 2 hours under an Ar atmosphere. Thereafter, the reaction solution was poured into 250 mL of ethyl acetate, and the precipitated product was separated by a centrifuge and recovered by decantation. Furthermore, the recovered product was washed five times with water (about 8 mL) to obtain a polysiloxane composition (hereinafter referred to as POSS-ODMS-Ph(OH)2). Since POSS-ODMS-Ph(OH)2 becomes insoluble when dried, it was recovered and stored as an ethanol solution.

[0048] Similarly, 3-hydroxytyramine hydrochloride (dopamine hydrochloride) [(MW=189.64g / mol, purity: 98%): 1.8mmol=0.3483g] was dissolved in 1.2mL of dehydrated DMF, and triethylamine [(MW=101.19g / mol, purity: 99%): 3.6mmol=0.3680g] was dissolved in 1.2mL of dehydrated DMF, and the obtained solutions were mixed. The mixed solution was added to the previously prepared reaction solution of POSS-CIm-PDMS, and heated and stirred at about 50°C for 2 hours under an Ar atmosphere. Thereafter, the reaction solution was poured into 330mL of ethyl acetate, and the precipitated product was separated by a centrifuge and recovered by decantation. Furthermore, the recovered product was washed five times with water (about 8mL) to obtain a polysiloxane composition (hereinafter referred to as POSS-PDMS-Ph(OH)2). Since POSS-PDMS-Ph(OH)2 becomes insoluble when dried, it was recovered and stored as an ethanol solution.

[0049] Each of the above steps is an example of the catechol group introduction step S4 shown in Figure 2. The dopamine hydrochloride used in each of the above steps is an example of the catecholamine described above. According to each of the above steps, as shown in Figure 4, a catechol group is introduced to the substituent R'' of the POSS, which is a cage structural unit, in a form linked to a urea bond. This catechol constitutes a side chain of the polysiloxane composition, as shown in Figure 1.

[0050] Furthermore, according to each of the above steps, the amino groups bonded to both ends of the siloxane chain shown in Figure 3 are replaced with urea bonds as shown in Figure 4. In this way, the chain structural unit obtained through each of the above steps has urea bonds arranged at both ends of the siloxane chain. This chain structural unit constitutes a side chain of the polysiloxane composition as shown in Figure 1. Note that in Figure 1, the urea bonds intervening between the cage structural unit and the siloxane chain are not shown.

[0051] As described above, by varying the charge ratio (molar ratio) of POSS-CIm to ODMS-AP or PDMS-AP in the precursor polysiloxane composition producing step S3, six types of polysiloxane compositions according to Examples 1 to 6 were obtained.

[0052] The ratio of POSS-CIm to ODMS-AP or PDMS-AP is shown in Table 1. Table 1 also shows the ratio of dopamine hydrochloride.

[0053] [Table 1]

[0054] 5 shows the FT-IR spectrum of the polysiloxane composition according to Examples 1 to 6. In each of Examples 1 to 6, the absorption peak derived from the urea bond was observed at 1632 cm -1 Near and 1575cm -1 This indicates that the urea bond was properly formed in the above-mentioned catechol group introduction step S4.

[0055] In addition, the FT-IR spectrum also confirmed absorption peaks due to siloxane bonds and absorption peaks due to bonds between silicon atoms and methyl groups.

[0056] FIG. 6 shows the results of the polysiloxane compositions according to Examples 1 to 4. 1 The H-NMR spectrum is shown. 1 In the 1 H-NMR spectrum, a signal f derived from a methylene proton adjacent to the urea bond and a signal i derived from an aromatic ring of the catechol component were observed.

[0057] Furthermore, signals c and b derived from methylene protons adjacent to the silicon atoms of Am-T8-POSS and the dimethylsiloxane chain were confirmed, suggesting that the polymer has a structure in which a catechol moiety is introduced into the polymer in which POSS and the siloxane chain are linked.

[0058] The evaluation results when the polysiloxane compositions according to Examples 1 to 6 were used as adhesives will be described below.

[0059] The procedure for preparing the evaluation sample will be described with reference to Fig. 7. A paste-like polysiloxane composition was applied to each of a pair of aluminum plates, and the areas where the polysiloxane composition was applied (hereinafter referred to as adhesive surfaces) were attached to each other and fixed with clips, and then heated and dried at 150°C for 12 hours. The area of ​​the adhesive surfaces was 125 mm2. 2 In this manner, samples for evaluating homogeneous material adhesion according to Examples 1-6 were obtained.

[0060] First, the evaluation results of heat resistance will be described. Each of the samples for evaluating homogeneous adhesion according to Examples 1 to 6 was heated in an oven with a 5 kg weight suspended therefrom. The heating temperature was gradually increased. During heating, the load of the weight acts as a shear force on the bonding surfaces of the pair of aluminum plates.

[0061] The results of the heat resistance test are shown in Fig. 8. The homogeneous material adhesion evaluation sample according to Example 4 exhibited heat resistance up to 120°C. That is, the bonded state between the pair of aluminum plates was maintained until the temperature reached 120°C. The homogeneous material adhesion evaluation sample according to Example 5 exhibited heat resistance up to 180°C. The homogeneous material adhesion evaluation sample according to Example 6 exhibited heat resistance up to 170°C.

[0062] Furthermore, in the sample for evaluating homogeneous adhesion according to Example 1-3, the bonded state between the pair of aluminum plates was maintained even when the temperature reached 250° C. That is, the sample for evaluating homogeneous adhesion according to Example 1-3 exhibited heat resistance of 250° C. or higher.

[0063] As described above, it was confirmed that the samples for evaluating homogeneous adhesion according to Examples 1-6 exhibited heat resistance of 120° C. or more. This is presumably because in the adhesive made of the polysiloxane composition, a network structure was formed by crosslinking due to the multifunctional compound POSS and crosslinking between catechol groups due to heating, which resulted in suppressing softening of the adhesive at high temperatures.

[0064] The difference between the manufacturing conditions in Examples 1-3 and 4-6 is whether PDMS or ODMS was used as the chain structural unit, as shown in Table 1. According to the results of the heat resistance test shown in Fig. 8, in order to obtain particularly excellent heat resistance, it can be said that it is preferable to use ODMS rather than PDMS as the chain structural unit.

[0065] That is, it is particularly preferable that the degree of polymerization N of the diorganosiloxane unit in the siloxane chain constituting the chain structural unit is not more than 5. The degree of polymerization N has a relationship of N=n+1 with the above-mentioned degree of polymerization n of the main part.

[0066] Next, in order to examine the hot adhesion between dissimilar materials, the polysiloxane compositions of Examples 1 and 3 were used as adhesives to prepare evaluation samples (hereinafter referred to as dissimilar material adhesion evaluation samples) by bonding a pair of aluminum plates and stainless steel plates in the same manner as in the preparation procedure for the evaluation samples described above.

[0067] For comparison, a sample for evaluating adhesion of different materials was also prepared using a commercially available acrylic resin adhesive (two-liquid radical polymerization type) as Commercial Reference Example 1. A sample for evaluating adhesion of different materials was also prepared using a commercially available epoxy adhesive containing micro iron powder as Commercial Reference Example 2.

[0068] Then, similarly to the case of FIG. 8, each of the samples for evaluating adhesion of dissimilar materials was heated in an oven with a weight of 5 kg suspended from each of the samples for evaluating adhesion of dissimilar materials.

[0069] The results of this heat resistance test are shown in Figure 9. In the samples for evaluating adhesion of different materials according to Examples 1 and 3, no separation occurred even when heated to 150°C, and adhesion was maintained even when cooled to room temperature. On the other hand, in the commercially available Reference Example 1, peeling occurred at 140°C, and in the commercially available Reference Example 2, peeling occurred at 100°C.

[0070] The reason why the heat resistance of Examples 1 and 3 was superior to that of the commercially available Reference Examples 1 and 2 is thought to be that the crosslinking by the polyfunctional compound POSS and the crosslinking between catechol groups by heating adequately suppressed the softening of the adhesive at high temperatures, while the flexibility of the ODMS component alleviated the thermal distortion caused by the difference in the thermal expansion coefficient between different materials.

[0071] Next, the results of evaluation of the adhesive properties at room temperature are described. At room temperature, a tensile shear test was performed in which a pair of aluminum plates in the samples for evaluating homogeneous adhesion according to Examples 1-6 were pulled apart in a direction parallel to their adhesive surfaces, and a stress-strain curve was measured.

[0072] 10 shows a stress-strain diagram of the homogeneous material adhesion evaluation samples according to Examples 1 to 6. The homogeneous material adhesion evaluation sample according to Example 4 showed a shear strength of 1.82 MPa. The homogeneous material adhesion evaluation sample according to Example 6 showed a shear strength of 2.64 MPa. The homogeneous material adhesion evaluation sample according to Example 5 showed a shear strength of 5.52 MPa.

[0073] Furthermore, the adhesive surface of the sample for evaluating the adhesion of the same material according to Example 1-3 did not peel off even when pulled to 8.16 MPa (1020 N), which is the maximum stress measurable by the tensile shear tester used, and particularly strong adhesiveness was confirmed. Based on this result, it can be said that in order to obtain particularly excellent adhesiveness at room temperature, it is preferable to use ODMS as the chain structural unit rather than PDMS.

[0074] Next, in order to confirm the shear stress at the time of peeling of the homogeneous material adhesion evaluation sample of Example 1-3, the area of ​​the adhesive surface of the homogeneous material adhesion evaluation sample was reduced and the stress-strain curve was measured again.

[0075] The results are shown in Figure 11. The sample for evaluating the adhesion of the same material according to Example 1 had a bonding surface area of ​​54 mm 2 The sample for evaluating the adhesion of the same material according to Example 2 had a bonding surface area of ​​35 mm 2 The sample for evaluating the adhesion of the same material according to Example 3 had a bonding surface area of ​​42.5 mm2. 2 When the specimen was placed in the test piece, the shear strength was 18.1 MPa.

[0076] FIG. 11 also shows a stress-strain curve of a sample for evaluating adhesion of similar materials, prepared using a commercially available adhesive, as Commercial Reference Example 1-9. The commercially available reference example 1 uses a commercially available acrylic resin adhesive (two-liquid radical polymerization type) and has an adhesive surface area of ​​40 mm 2 The shear strength was 14.0 MPa. Commercial Reference Example 2 uses a commercially available epoxy adhesive containing micro iron powder (two-liquid addition reaction type), and the adhesive surface area is 48 mm 2 The shear strength was 13.4 MPa. In the commercially available Reference Example 3, a commercially available polyvinyl acetate adhesive (water-dispersed, dried, solidified type) was used, and the adhesive surface area was 125 mm 2 The shear strength was 0.7 MPa. In the commercially available Reference Example 4, a commercially available cyanoacrylate adhesive (moisture curing type) was used, and the adhesive surface area was 125 mm 2 The shear strength was 1.6 MPa. In the commercially available Reference Example 5, a commercially available cyanoacrylate adhesive (moisture curing type) was used, and the adhesive surface area was 125 mm 2 The shear strength was 3.1 MPa. In the commercially available Reference Example 6, a commercially available epoxy adhesive (two-liquid addition reaction type) was used, and the adhesive surface area was 125 mm 2 The shear strength was 3.9 MPa. In the commercially available Reference Example 7, a commercially available cyanoacrylate adhesive (moisture curing type) was used, and the adhesive surface area was 125 mm 2 The shear strength was 4.4 MPa. Commercially available Reference Example 8 uses a commercially available cyanoacrylate adhesive (moisture curing type) and has a bonding surface area of ​​125 mm 2 The shear strength was 4.3 MPa. In the commercially available Reference Example 9, a commercially available vinyl acetate resin adhesive (hot melt type) was used, and the adhesive surface area was 125 mm 2 The shear strength was 4.6 MPa.

[0077] As shown in FIG. 11, it was confirmed that the samples for evaluating adhesion to similar materials according to Examples 1-3 exhibited shear strength comparable to that of commercially available Reference Examples 1 and 2 at room temperature, and far superior to that of commercially available Reference Examples 3-9.

[0078] Next, the evaluation results of water resistance will be described. As a representative, the water resistance was examined for the homogeneous material adhesion evaluation sample according to Example 1-3. Specifically, the homogeneous material adhesion evaluation sample was immersed in water for two days, the water was wiped off, and the stress-strain curve was immediately measured.

[0079] The results are shown in Fig. 12. The homogeneous material adhesion evaluation sample according to Example 2 showed a shear strength of 4.69 MPa, and the homogeneous material adhesion evaluation sample according to Example 3 showed a shear strength of 5.28 MPa. Furthermore, the homogeneous material adhesion evaluation sample according to Example 1 did not peel off even when pulled up to 8.16 MPa (1020 N), which was the maximum stress measurable by the tensile shear tester used, confirming particularly strong water resistance.

[0080] As shown in Table 1, in Example 1, the ratio of POSS-CIm, which is a precursor of the cage structural unit, to ODMS-AP, which is a precursor of the chain structural unit, is higher at the charging stage than in Examples 2 and 3. The molar ratio of polyhedral oligosilsesquioxane / siloxane chain in the polysiloxane composition can be considered to be approximately equal to the charging ratio shown in Table 1. That is, the ratio of catechol groups in the polysiloxane composition of Example 1 is higher than the ratio of catechol groups in the polysiloxane compositions of Examples 2 and 3.

[0081] In FIG. 12, the reason why Example 1 showed superior water resistance to Examples 2 and 3 is presumably because the proportion of catechol groups in the polysiloxane composition was high, and the strong interaction between the catechol groups and the surface of the material prevented water molecules from penetrating, thereby suppressing the swelling of the polysiloxane composition. [Industrial Applicability]

[0082] The adhesive according to the present disclosure can be used, for example, for bonding parts that require heat resistance. As a specific example, the adhesive according to the present disclosure can be used for bonding parts that are exposed to heat, such as the engine area or muffler area of ​​an automobile. Since the cured product of the adhesive according to the present disclosure has heat resistance, it can stably maintain a strong bonded structure even when exposed to heat generated by the operation of the engine.

[0083] The adhesives disclosed herein can also be used to bond different materials together, making it possible to realize multi-material structures in which different materials are placed in the right places. Multi-material structures contribute to reducing the weight of vehicles, such as automobiles and aircraft.

Claims

1. a main chain having a structure in which a cage structural unit made of a polyhedral oligosilsesquioxane and a chain structural unit having a siloxane chain are repeated, the cage structural unit being adjacent to each other and connected to the chain structural unit; a catechol group bonded to each of the cage structural units constituting the main chain; and The polysiloxane composition comprising:

2. The siloxane chain has a structure in which siloxane units, which are D units, are linked in a linear chain, the degree of polymerization of the siloxane units in the siloxane chain is 30 or less; The polysiloxane composition of claim 1.

3. In the polysiloxane composition, the molar ratio of the polyhedral oligosilsesquioxane to the siloxane chain is 1 / 3 or more and 1 or less. The polysiloxane composition according to claim 1 or 2.

4. The catechol group is bonded to the polyhedral oligosilsesquioxane via a urea bond structure. The polysiloxane composition according to any one of claims 1 to 3.

5. The chain structural unit has urea bonds arranged at both ends of the siloxane chain. The polysiloxane composition according to any one of claims 1 to 4.

6. A composition comprising the polysiloxane composition according to any one of claims 1 to 5. glue.

7. a precursor polysiloxane composition producing step of producing a precursor polysiloxane composition which is a copolymer of a cage-like structural unit composed of a polyhedral oligosilsesquioxane having a substituent containing a urea group and a chain-like structural unit having a siloxane chain; a catechol group introduction step of reacting the precursor polysiloxane composition with a catecholamine to introduce a catechol group into the substituent via a urea bond containing the urea group; A method for producing a polysiloxane composition comprising:

8. Prior to the step of producing the precursor polysiloxane composition, a precursor cage structure unit preparation step of preparing a precursor cage structure unit composed of a polyhedral oligosilsesquioxane having a compound containing an ammonium group as a substituent; a urea group forming step of reacting the precursor cage structural unit with a carbonyl compound to replace the compound containing the ammonium group in the substituent of the precursor cage structural unit with the compound containing the urea group; The method of claim 7 further comprising:

9. the chain structural unit used to generate the precursor polysiloxane composition in the precursor polysiloxane composition generating step has amino groups arranged at both ends of the siloxane chain, In the catechol group introduction step, the amino group is replaced with a urea bond by a reaction between the precursor polysiloxane composition and the catecholamine. A method for producing the polysiloxane composition according to claim 7 or 8.

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