Cyclic organopolysiloxanes, silicone compositions, adhesive aids, and adhesives

Abstract

To provide cyclic organopolysiloxane which is excellent in adhesion to metal and a resin, and can stably impart adhesion even when being exposed to a high temperature and high humidity environment for a long time, a silicone composition and an adhesive auxiliary containing the same, and an adhesive.SOLUTION: Cyclic organopolysiloxane is represented by formula (1) (wherein, R1 is independently a C1-C8 alkylene group; m is an integer of 1 to 3; n is an integer of 1 to 3; the total of m and n is 4 to 6; and the arrangement order of a siloxane unit is arbitrary).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to cyclic organopolysiloxanes, silicone compositions containing the same, adhesive aids, and adhesives. [Background technology]

[0002] Numerous cyclic organopolysiloxane compounds having functional groups have been developed as adhesive additives to impart adhesion to various substrates to silicone compositions (Patent Documents 1 and 2). With the increasing diversity of adherend combinations, it is desirable for a single adhesive additive to exhibit adhesion to multiple adherends such as metals and resins.

[0003] Furthermore, the performance requirements regarding durability have also increased, with the need to maintain adhesive properties even when exposed for extended periods in high-temperature, high-humidity environments such as 85°C and 85%RH. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2013-032498 [Patent Document 2] Patent No. 4013023 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention has been made in view of the above circumstances, and aims to provide a cyclic organopolysiloxane, a silicone composition containing the same, an adhesive, and an adhesive that have excellent adhesion to metals and resins and can provide stable adhesion even when exposed to high temperature and high humidity environments for a long period of time. [Means for solving the problem]

[0006] To solve the above problems, the present invention provides a cyclic organopolysiloxane represented by the following general formula (1). [ka] (In the formula, R 1 Each of these is an alkylene group with 1 to 8 carbon atoms, where m is an integer from 1 to 3, n is an integer from 1 to 3, and the sum of m and n is from 4 to 6. The order of the siloxane units is arbitrary.

[0007] Such cyclic organopolysiloxanes exhibit excellent adhesion to metals and resins, as well as superior durability in high-temperature and high-humidity environments.

[0008] Furthermore, the present invention provides an adhesive aid comprising the above-mentioned cyclic organopolysiloxane.

[0009] Such adhesive additives exhibit excellent adhesion to metals and resins, as well as superior durability in high-temperature and high-humidity environments.

[0010] Furthermore, the present invention provides a silicone composition containing the above-mentioned cyclic organopolysiloxane.

[0011] Such silicone compositions exhibit excellent adhesion to metals and resins, and maintain stable adhesion even when exposed to high-temperature and high-humidity environments for extended periods.

[0012] Furthermore, the present invention provides an adhesive comprising the above-mentioned silicone composition.

[0013] Such adhesives exhibit excellent adhesion to metals and resins, and maintain stable adhesion even when exposed to high-temperature and high-humidity environments for extended periods. [Effects of the Invention]

[0014] The cyclic organopolysiloxane of the present invention has excellent adhesion to metals and resins, and maintains adhesion even when exposed to a high-temperature and high-humidity environment for a long time, so it is useful as an adhesion aid for imparting adhesion to silicone compositions and the like. In particular, it can be suitably used in automotive applications, electrical and electronic applications, etc. where reliability against high-temperature and high-humidity environments is required. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0015] [Figure 1] 1H NMR spectrum of cyclic organopolysiloxane 1 according to Synthesis Example 1. [Figure 2] 1H NMR spectrum of cyclic organopolysiloxane 2 according to Synthesis Example 2. [MODE FOR CARRYING OUT THE INVENTION]

[0016] As described above, there has been a demand for the development of a cyclic organopolysiloxane that serves as an adhesion aid having excellent adhesion to metals and resins and capable of stably imparting adhesion even when exposed to a high-temperature and high-humidity environment for a long time.

[0017] As a result of intensive studies to achieve the above object, the present inventors have found that a specific cyclic organopolysiloxane has excellent adhesion to metals and resins and high durability against high-temperature and high-humidity environments, and have completed the present invention.

[0018] That is, the present invention is a cyclic organopolysiloxane represented by the following general formula (1). [Chemical Formula] (wherein R 1 each independently is an alkylene group having 1 to 8 carbon atoms, m is an integer of 1 to 3, n is an integer of 1 to 3, and the sum of m and n is 4 to 6. The arrangement order of the siloxane units is arbitrary.)

[0019] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0020] [Cyclic organopolysiloxane] The present invention relates to a cyclic organopolysiloxane represented by the following general formula (1). [ka] (In the formula, R 1 Each of these is an alkylene group with 1 to 8 carbon atoms, where m is an integer from 1 to 3, n is an integer from 1 to 3, and the sum of m and n is from 4 to 6. The order of the siloxane units is arbitrary.

[0021] R 1 The alkylene group is independently an alkylene group having 1 to 8 carbon atoms, and the alkylene group may be linear, branched, or cyclic. Specific examples include methylene, ethylene, trimethylene, propylene, tetramethylene, isobutylene, dimethylethylene, pentamethylene, 2,2-dimethyltrimethylene, hexamethylene, heptamethylene, and octamethylene. Methylene, ethylene, and trimethylene groups are preferred, and trimethylene groups are particularly preferred.

[0022] The sum of m and n is between 4 and 6, preferably 4 or 5, and particularly preferably 4.

[0023] m is an integer between 1 and 3, preferably 2 or 3, and particularly preferably 3.

[0024] n is an integer between 1 and 3, preferably 1 or 2, and particularly preferably 1.

[0025] Examples of such cyclic organopolysiloxanes include those represented by the following structural formulas, but are not limited to these structures. [ka]

[0026] [Adhesive enhancer] The adhesive aid of the present invention comprises the above-mentioned cyclic organopolysiloxane. Such an adhesive aid exhibits excellent adhesion to metals and resins, and excellent durability in high-temperature and high-humidity environments.

[0027] [Silicone composition] The silicone composition of the present invention contains the above-mentioned cyclic organopolysiloxane. Such a silicone composition exhibits excellent adhesion to metals and resins, and maintains stable adhesion even when exposed to high temperature and high humidity environments for extended periods.

[0028] The components included in the silicone composition of the present invention are not particularly limited, but examples include a silicone composition comprising (A) an organopolysiloxane having two or more aliphatic unsaturated hydrocarbon groups bonded to a silicon atom in one molecule, (B) an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to a silicon atom in one molecule, (C) a platinum group metal catalyst, (D) a reaction regulator, (E) the cyclic organopolysiloxane of the present invention, and (F) an inorganic filler.

[0029] [glue] The adhesive of the present invention comprises the above-mentioned silicone composition. Such an adhesive exhibits excellent adhesion to metals and resins, and maintains stable adhesion even when exposed to high-temperature and high-humidity environments for extended periods.

[0030] [Method for producing cyclic organopolysiloxanes] The method for producing the cyclic organopolysiloxane of the present invention is not particularly limited, but for example, the cyclic organopolysiloxane of the present invention can be produced by reacting a cyclic methylhydrogenpolysiloxane represented by the following general formula (2) with an alkenyl group-containing benzodioxole represented by the following general formula (3) in the presence of a platinum group metal catalyst. [ka] (In the formula, l is an integer between 4 and 6.) [ka] (In the formula, R 2 (This refers to an alkenyl group with 2 to 8 carbon atoms.)

[0031] l is an integer between 4 and 6, preferably 4 or 5, and particularly preferably 4.

[0032] R 2 This is an alkenyl group having 2 to 8 carbon atoms. The alkenyl group may be linear, branched, or cyclic. Specific examples include vinyl, allyl, propenyl, butenyl, and hexenyl groups, with allyl groups being preferred.

[0033] The alkenyl group-containing benzodioxole represented by general formula (3) may be used alone or in combination of two or more types. [Examples]

[0034] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited to these.

[0035] [Synthesis Example 1] Synthesis of Cyclic Organopolysiloxane 1 2,4,6,8-tetramethylcyclotetrasiloxane (MW=240.51 g / mol; 10.0 mmol=2.4051 g) and safrole [(MW=162.19 g / mol, purity: 98%); 10.0 mmol=1.6550 g] were each dissolved in 15 mL of dichloromethane and mixed. When the total mass of 2,4,6,8-tetramethylcyclotetrasiloxane and safrole was 97 parts by mass, a platinum catalyst [(platinum-divinyltetramethyldisiloxane complex / toluene solution, 0.5 wt%); 3 wt%=0.1256 g] was dissolved in dichloromethane so that the catalyst amounted to 3 parts by mass, and this was added to the mixed solution and stirred at room temperature for 4 hours. Then, 1 part by mass of activated carbon (0.6404 g) was added to 100 parts by mass of the mixed solution, and the mixture was stirred for a further 1 hour. Cyclic organopolysiloxane 1 was obtained by removing activated carbon by suction filtration and removing dichloromethane at 30°C using an evaporator [Yield: 3.6390g, Yield: 81%, Yield calculated using FW = 448.10g / mol]. [{[CH3SiO(CH2)3C6H3(OCH2O),FW=222.31g / mol]×0.32 + [CH3SiO(H),FW=60.13g / mol]×0.68}×4 = 448.10g / mol] [ka]

[0036] The obtained cyclic organopolysiloxane 1 1 The 1H NMR spectrum is shown in Figure 1. 1 From 1H NMR, a methylene signal (b) adjacent to the silicon atom was observed, confirming the introduction of safrol. Furthermore, by calculating the composition ratio from the methylene signal (d) adjacent to the aromatic ring and the signal (●) originating from Si-H, it was confirmed that an average of 1 unit [4 × 0.32 ≈ 1 unit (1.28)] of safrol was introduced in 4 units.

[0037] [Synthesis Example 2] Synthesis of Cyclic Organopolysiloxane 2 2,4,6,8-tetramethylcyclotetrasiloxane (MW=240.51 g / mol; 5.0 mmol = 1.2026 g) and safrole [(MW=162.19 g / mol, purity: 98%); 10.0 mmol = 1.6550 g] were each dissolved in 15 mL of dichloromethane and mixed. When the total mass of 2,4,6,8-tetramethylcyclotetrasiloxane and safrole was taken as 97 parts by mass, a platinum catalyst that provides 3 parts by mass of the catalyst [platinum-divinyltetramethyldisiloxane complex / toluene solution, 0.5 wt%; 3 wt% = 0.0884 g] was dissolved in dichloromethane, added to the mixed solution, and stirred at room temperature for 4 hours. Thereafter, 1 part by mass of activated carbon (0.6280 g) based on 100 parts by mass of the mixed solution was added, and the mixture was further stirred for 1 hour. Activated carbon was removed by suction filtration, and dichloromethane was removed at 30°C using an evaporator to obtain cyclic organopolysiloxane 2 [yield: 2.7082 g, yield: 95%, the yield was calculated using FW=571.36 g / mol]. [{[CH3SiO(CH2)3C6H3(OCH2O), FW=222.31 g / mol] × 0.51 + [CH3SiO(H), FW=60.13 g / mol] × 0.49} × 4 = 571.36 g / mol]

Chemical Formula

[0038] Of the obtained cyclic organopolysiloxane 2 1 The ¹H NMR spectrum is shown in Figure 2. 1 From ¹H NMR, a methylene signal (b) adjacent to the silicon atom was observed, confirming the introduction of safrole. In addition, the composition ratio was calculated from the methylene signal (d) adjacent to the aromatic ring and the signal derived from Si-H (●), and it was confirmed that an average of 2 units of safrole [4 × 0.51 ≒ 2 units (2.04)] was introduced into 4 units.

[0039] [Example 1, Comparative Example 1] Preparation of Silicone Composition The following components (A) to (F) were mixed at the compounding ratio (parts by mass) shown in Table 1 to prepare a silicone composition. Component (F) was added to component (A) and mixed using a three-roll mixer, followed by the addition and mixing of components (C) and (D) in that order, and finally the addition and mixing of components (B) and (E), followed by degassing under reduced pressure to obtain a silicone composition. The obtained silicone composition was applied to substrates (aluminum plate and PBT (polybutylene terephthalate) resin plate), respectively, and heated in an oven at 150°C for 60 minutes to cure the silicone composition, thereby creating test specimens with a cured layer of the silicone composition on the substrate. The adhesion of each test specimen before and after exposure to an environment of 85°C and 85%RH for 100 hours was evaluated using the method described below, and the results are shown in Table 1.

[0040] [Adhesion evaluation] An incision was made at the adhesive interface at the end of each test specimen using a razor blade, and the cured silicone was pulled by hand. Those that remained bonded were evaluated as "bonded," and those that separated at the interface between the substrate and the cured silicone were evaluated as "separated."

[0041] (A): Dimethylpolysiloxane with both ends sealed with dimethylvinylsilyl groups (viscosity of 100,000 mPa·s at 25°C as measured by a rotational viscometer) (B): Methylhydrogenpolysiloxane represented by the following formula [ka] (C): Toluene solution of platinum-divinyltetramethyldisiloxane complex (platinum concentration 0.5% by mass) (D): Ethinylcyclohexanol (reaction control agent) (E-1): Cyclic organopolysiloxane 1 obtained in Synthesis Example 1 (E-2): Cyclic organopolysiloxane represented by the following structural formula (comparative component) [ka] (F): BET with a specific surface area of ​​300 m², surface-treated with hexamethyldisilazane. 2 / g of fuzzy silica

[0042] [Table 1]

[0043] As shown in Table 1, the silicone composition containing the cyclic organopolysiloxane of the present invention (Example 1) showed good adhesion to both aluminum plates and polybutylene terephthalate resin plates, and maintained its adhesion even after exposure to an environment of 85°C and 85%RH for 100 hours.

[0044] On the other hand, in Comparative Example 1, which used a glycidyl ether-type cyclic organopolysiloxane, conventionally known as an adhesive aid, instead of the cyclic organopolysiloxane of the present invention, adhesion to aluminum could not be maintained after exposure to a high-temperature, high-humidity environment.

[0045] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. A cyclic organopolysiloxane characterized by being represented by the following general formula (1). 【Chemistry 1】 (In the formula, R １ Each of these is an alkylene group having 1 to 8 carbon atoms, where m is an integer from 1 to 3, n is an integer from 1 to 3, and the sum of m and n is 4 to 6. The order of the siloxane units is arbitrary.

2. An adhesive aid characterized by comprising the cyclic organopolysiloxane described in claim 1.

3. A silicone composition characterized by containing the cyclic organopolysiloxane described in claim 1.

4. An adhesive characterized by comprising the silicone composition described in claim 3.

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