Recyclable curable silicone resin composition

Abstract

Provided is a silicone resin composition which can be easily liquefied by heating and which can be recycled. A curable silicone resin composition comprising (A) a furyl group-containing organopolysiloxane having a number average molecular weight of 500 to 40,000 and (B) a maleimide group-containing organopolysiloxane having a number average molecular weight of 500 to 40,000. A method for recycling a curable silicone resin composition, which comprises a step for heating a cured product of the curable silicone resin composition to 130 DEG C or higher.

Description

Technical Field

[0001] The present invention relates to a recyclable curable silicone resin composition. Background Art

[0002] Silicone resins are used in a variety of fields, such as sealing materials for buildings and coating agents for automobile bodies. However, since silicone resins are thermosetting resins, they are difficult to degrade and recycle (reuse) by heating. Although the silicone resins can be depolymerized by main chain cleavage when using acids and alkalis or when exposed to ultra-high temperatures exceeding 400°C, they are difficult to recycle because of the problems of waste liquid disposal generated by the neutralization process and the energy required for repolymerization.

[0003] Patent Document 1 discloses an attempt to impart degradability to a silicone resin by blending heat-expandable microcapsules into the resin, but does not describe the recycling of the silicone resin after degradation.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2004-123943 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] Therefore, an object of the present invention is to provide a silicone resin composition that can be easily liquefied by heating and can be recycled.

[0009] Solutions to the problem

[0010] The present inventors have conducted intensive studies to solve the above problems and have found that a silicone resin composition containing a furanyl group-containing organopolysiloxane and a maleimide group-containing organopolysiloxane is a curable silicone resin composition that liquefies at a temperature of 130° C. or higher and is recyclable, thereby completing the present invention.

[0011] That is, the present invention provides the following recyclable curable silicone resin composition. [1]

[0013] A curable silicone resin composition comprising the following components (A) and (B):

[0014] (A) a furanyl-containing organopolysiloxane represented by the following formula (1) and having a number average molecular weight of 500 to 40,000,

[0015] [Chemical formula 1]

[0016]

[0017] (In formula (1), R 1 are independently selected from the group consisting of a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, and a furyl group represented by the following formula (2) and formula (3), and R in one molecule 1 Two or more of them are furanyl groups represented by the following formula (2) or (3). a is a number greater than or equal to 2, b is a number greater than or equal to 0, c is a number greater than or equal to 0, d is a number greater than or equal to 0, and a+b+c+d is 2≤a+b+c+d≤500.

[0018] [Chemical formula 2]

[0019]

[0020] (In formula (2) and formula (3), R 2 and R 3 Each is independently a hydrogen atom or a straight-chain alkyl group having 1 to 10 carbon atoms. The dotted line represents an atomic bond.)

[0021] (B) an organopolysiloxane containing a maleimide group, represented by the following formula (4), having a number average molecular weight of 500 to 40,000,

[0022] [Chemical formula 3]

[0023]

[0024] (In formula (4), R 4 are independently a monovalent hydrocarbon group having 1 to 10 carbon atoms or a maleimide group represented by the following formula (5), and R 4 Two or more of them are maleimide groups represented by the following formula (5). e is a number greater than or equal to 2, f is a number greater than or equal to 0, g is a number greater than or equal to 0, h is a number greater than or equal to 0, and e+f+g+h is 2≤e+f+g+h≤500.

[0025] [Chemical formula 4]

[0026]

[0027] (In formula (5), R 5 are independently hydrogen atoms or methyl groups. Dashed lines represent atomic bonds.) [2]

[0029] The curable silicone resin composition according to [1], wherein

[0030] Both or either of d in Formula (1) and h in Formula (4) is 0. [3]

[0032] The curable silicone resin composition according to [1] or [2], wherein

[0033] Both or either of c in formula (1) and g in formula (4) is 0. [4]

[0035] The curable silicone resin composition according to any one of [1] to [3], wherein

[0036] c and d in formula (1) and g and h in formula (4) are all 0. [5]

[0038] A method for recycling a curable silicone resin composition, wherein:

[0039] The method comprises the step of heating the cured product of the curable silicone resin composition according to any one of [1] to [4] to 130° C. or higher.

[0040] Effects of the Invention

[0041] According to the present invention, a curable silicone resin composition that can be liquefied when heated at a temperature of 130° C. or higher and can be recycled can be provided. In addition, the silicone resin composition can be cured at a relatively low temperature of 0° C. or higher and 100° C. or lower. In addition, the curable silicone resin composition of the present invention is useful in applications such as adhesives, pressure-sensitive adhesives, encapsulants, and coating agents. DETAILED DESCRIPTION

[0042] Hereinafter, the present invention will be described in detail.

[0043] [(A) Furanyl-containing organopolysiloxane]

[0044] The furan group-containing organopolysiloxane is the component (A) of the present invention, has a number average molecular weight of 500 to 40,000, and is represented by the following formula (1).

[0045] [Chemical formula 5]

[0046]

[0047] In the above formula (1), R 1 are independently selected from the group consisting of a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, and a furyl group represented by the following formula (2) and formula (3), and R in one molecule 1Two or more of them are furyl groups represented by the following formula (2) or (3). a is a number greater than or equal to 2, b is a number greater than or equal to 0, c is a number greater than or equal to 0, d is a number greater than or equal to 0, and a+b+c+d is 2≦a+b+c+d≦500.

[0048] [Chemical formula 6]

[0049]

[0050] In the above formula (2) and formula (3), R 2 and R 3 Each independently represents a hydrogen atom or a linear alkyl group having 1 to 10 carbon atoms. The dotted line represents an atomic bond.

[0051] In the above formula (1), R 1 are independently selected from the group consisting of a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, and a furanyl group represented by the above formula (2) and formula (3). 1 The monovalent hydrocarbon group having 1 to 10 carbon atoms may be exemplified by alkyl groups such as methyl, ethyl, propyl and butyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; aryl groups such as phenyl and tolyl. Alkoxy groups having 1 to 4 carbon atoms may be exemplified by methoxy, ethoxy, propoxy and butoxy.

[0052] R in 1 molecule 1 Two or more, preferably 2 to 4, of the groups are furyl groups represented by the above formula (2) or (3). As the group other than the furyl group, an alkyl group, a cycloalkyl group and an aryl group are preferred, and a methyl group and a phenyl group are more preferred.

[0053] In the above formula (2) and formula (3), R 2 and R 3 are independently a hydrogen atom or a linear alkyl group having 1 to 10 carbon atoms. 2 or R 3 The straight-chain alkyl group having 1 to 10 carbon atoms represented by R includes methyl, ethyl, propyl and butyl. 2 and R 3 , preferably a hydrogen atom or a methyl group.

[0054] In the above formula (1), a is 2 or more, preferably 2 to 12, b is 0 or more, preferably 1 to 498, more preferably 5 to 300, c is 0 or more, preferably 0 to 10, more preferably 0. d is 0 or more, preferably 0 to 5, more preferably 0. Furthermore, a+b+c+d is 2≤a+b+c+d≤500, preferably 2≤a+b+c+d≤300, more preferably 3≤a+b+c+d≤300, and even more preferably 4≤a+b+c+d≤150. If a+b+c+d is greater than 500, the viscosity of the furan group-containing organopolysiloxane may become high, and the handleability may deteriorate.

[0055] The molecular weight of the furan group-containing organopolysiloxane of the present invention is 500 to 40,000, preferably 1,000 to 20,000, and more preferably 1,000 to 10,000, in terms of number average molecular weight. If the number average molecular weight is less than 500, the properties such as flexibility derived from the (poly)siloxane may not be exhibited, and if the molecular weight exceeds 40,000, the viscosity of the furan group-containing organopolysiloxane may become high, and the workability may deteriorate, which is not preferred.

[0056] In addition, the number average molecular weight in the present invention is a value analyzed by GPC (gel permeation chromatography) using polystyrene under the following conditions as a standard substance.

[0057] [Measurement conditions]

[0058] Elution solvent: tetrahydrofuran (THF)

[0059] Flow rate: 0.6mL / min

[0060] Detector: Differential Refractive Index Detector (RI)

[0061] Column: TSK Guardcolumn SuperH-H

[0062] TSKgel SuperHM-N(6.0mmI.D.×15cm×1)

[0063] TSKgel SuperH2500(6.0mmI.D.×15cm×1)

[0064] (All manufactured by Tosoh Corporation of Japan)

[0065] Column temperature: 40°C

[0066] Sample injection volume: 50 μL (0.3 mass % THF solution)

[0067] [(B) Maleimide group-containing organopolysiloxane]

[0068] The maleimide group-containing organopolysiloxane is the component (B) of the present invention, has a number average molecular weight of 500 to 40,000, and is represented by the following formula (4).

[0069] [Chemical formula 7]

[0070]

[0071] In the above formula (4), R 4 are independently a monovalent hydrocarbon group having 1 to 10 carbon atoms or a maleimide group represented by the following formula (5), and R 4 Two or more, preferably 2 to 8, of the groups are maleimide groups represented by the following formula (5): e is a number greater than 2, f is a number greater than 0, g is a number greater than 0, h is a number greater than 0, and e+f+g+h is 2≤e+f+g+h≤500.

[0072] [Chemical formula 8]

[0073]

[0074] In the above formula (5), R 5 are independently hydrogen atoms or methyl groups. Dashed lines represent atomic bonds.

[0075] In the above formula (4), R 4 are independently a monovalent hydrocarbon group having 1 to 10 carbon atoms or a maleimide group represented by the above formula (5), and R 4 In formula (4), two or more of the groups represented by R are maleimide groups represented by the above formula (5). 4 The monovalent hydrocarbon group having 1 to 10 carbon atoms represented by , for example, alkyl groups such as methyl, ethyl, propyl and butyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; aryl groups such as phenyl and tolyl, etc. Among them, alkyl groups, cycloalkyl groups and aryl groups are preferred, and methyl and phenyl groups are more preferred.

[0076] In the above formula (5), R 5 It is a hydrogen atom or a methyl group. Among them, a hydrogen atom is preferred.

[0077] In the above formula (4), e is 2 or more, preferably 2 to 12, f is 0 or more, preferably 1 to 498, more preferably 5 to 300, g is 0 or more, preferably 0 to 10, more preferably 0. h is 0 or more, preferably 0 to 5, more preferably 0. And e+f+g+h is 2≤e+f+g+h≤500, preferably 2≤e+f+g+h≤300, more preferably 3≤e+f+g+h≤300, and further preferably 4≤e+f+g+h≤150. If e+f+g+h is greater than 500, the viscosity of the maleimide group-containing organopolysiloxane may become high, and the workability may be poor.

[0078] The molecular weight of the maleimide group-containing organopolysiloxane of the present invention is 500 to 40,000, preferably 1,000 to 20,000, and more preferably 1,000 to 10,000 in terms of number average molecular weight. If the number average molecular weight is less than 500, the properties such as flexibility derived from (poly)siloxane may not be exhibited, and if the number average molecular weight exceeds 40,000, the viscosity of the maleimide group-containing organopolysiloxane may become high, and the workability may be deteriorated.

[0079] The amount of the component (B) is preferably 1 to 2 equivalents, more preferably 1.1 to 1.5 equivalents, of the maleimide groups in the component (B) per 1 equivalent of the furan groups in the component (A).

[0080] In addition, in the composition of the present invention, the (A) component and the (B) component are preferably contained in an amount of 60 to 100 mass %, more preferably 80 to 100 mass %, and even more preferably 90 to 100 mass %.

[0081] [Other ingredients]

[0082] The curable silicone resin composition of the present invention may contain components other than the above components within the range not impairing the effects of the present invention. Components other than the above components include, for example, binders such as silica powder and metal fillers.

[0083] (Method for producing curable silicone resin composition)

[0084] As a method for producing the recyclable curable silicone resin composition of the present invention, a known method can be used as a mixing method of liquid substances. In particular, since (A) the organopolysiloxane containing a furan group and (B) the organopolysiloxane containing a maleimide group have excellent mutual compatibility, a uniform composition can be obtained by simply mixing them at room temperature (25°C).

[0085] When adding components other than (A) the furan group-containing organopolysiloxane and (B) the maleimide group-containing organopolysiloxane to the composition of the present invention, it is preferred that a mixture in which the components are preliminarily dispersed in the component (A) and / or the component (B) is simply mixed at room temperature (25° C.) by a known method.

[0086] [Method for curing curable silicone resin composition]

[0087] The curing method of the curable silicone resin composition of the present invention is to cure the composition at a temperature of 0°C to 100°C, preferably 15°C to 80°C, for 12 to 96 hours, preferably 24 to 72 hours.

[0088] [Method for recycling curable silicone resin]

[0089] The method for recycling a silicone resin which is a cured product of a curable silicone resin composition of the present invention comprises a step of heating at a temperature of 130° C. or higher, preferably 130° C. or higher and 160° C. or lower, for 3 to 30 minutes, preferably 3 to 10 minutes. The cured product of the curable silicone resin composition of the present invention is liquefied by the heating step, and the liquefied curable silicone resin composition is re-cured under the above-mentioned curing conditions, so that it can be recycled.

[0090] Example

[0091] Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not to be construed as being limitative by the Examples shown below.

[0092] <Example 1>

[0093] 3.79 g of a furanyl-containing organopolysiloxane represented by the following formula (6) (number average molecular weight of 7570) and 2.58 g of a maleimide-containing organopolysiloxane represented by the following formula (7) (number average molecular weight of 6880) were stirred at room temperature (25°C) for 5 minutes, and the obtained silicone resin composition was left standing at room temperature for 3 days to be cured. After the cured silicone resin composition was heated in an oven at 150°C for 5 minutes, the silicone resin composition was completely liquefied. The liquefied composition was left standing at room temperature for 3 days again and then cured again.

[0094] [Chemical formula 9]

[0095]

[0096] [Chemical formula 10]

[0097]

[0098] <Example 2>

[0099] 3.84 g of a furanyl-containing organopolysiloxane represented by the following formula (8) (number average molecular weight of 7680) and 2.58 g of a maleimide-containing organopolysiloxane represented by the above formula (7) (number average molecular weight of 6880) were stirred at room temperature (25°C) for 5 minutes, and the obtained silicone resin composition was left standing at room temperature for 3 days to cure. After the cured silicone resin composition was heated in an oven at 150°C for 5 minutes, the silicone resin composition was completely liquefied. The liquefied composition was left standing at room temperature for 3 days again and then cured again.

[0100] [Chemical formula 11]

[0101]

[0102] <Example 3>

[0103] 2.10 g of a furanyl-containing organopolysiloxane represented by the following formula (9) (number average molecular weight of 6310) and 2.58 g of a maleimide-containing organopolysiloxane represented by the above formula (7) (number average molecular weight of 6880) were stirred at room temperature (25°C) for 5 minutes, and the obtained silicone resin composition was left standing at room temperature for 3 days to cure. After the cured silicone resin composition was heated in an oven at 150°C for 5 minutes, the silicone resin composition was completely liquefied. The liquefied composition was left standing at room temperature for 3 days again and then cured again.

[0104] [Chemical formula 12]

[0105]

[0106] <Example 4>

[0107] 2.13 g of a furanyl-containing organopolysiloxane represented by the following formula (10) (number average molecular weight of 6400) and 2.58 g of a maleimide-containing organopolysiloxane represented by the above formula (7) (number average molecular weight of 6880) were stirred at room temperature (25°C) for 5 minutes, and the obtained silicone resin composition was left to stand at room temperature for 3 days to cure. After the cured silicone resin composition was heated in an oven at 150°C for 5 minutes, the silicone resin composition was completely liquefied. The liquefied composition was left to stand at room temperature for 3 days again and then cured again.

[0108] [Chemical formula 13]

[0109]

[0110] <Comparative Example 1>

[0111] 0.3 g of a furanyl-containing organopolysiloxane represented by the following formula (11) (number average molecular weight: 290) and 2.58 g of a maleimide-containing organopolysiloxane represented by the above formula (7) (number average molecular weight: 6880) were stirred at room temperature (25°C) for 5 minutes, and the obtained silicone resin composition was allowed to stand at room temperature for 3 days, but it only thickened and failed to cure.

[0112] [Chemical formula 14]

[0113]

Claims

1. A curable silicone resin composition comprising the following components (A) and (B): (A) a furanyl-containing organopolysiloxane represented by the following formula (1) and having a number average molecular weight of 500 to 40,000, [Chemical formula 1] In formula (1), R 1 are independently selected from the group consisting of a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, and a furyl group represented by the following formula (2) and formula (3), and R in one molecule 1 Two or more of them are furanyl groups represented by the following formula (2) or (3), a is a number greater than or equal to 2, b is a number greater than or equal to 0, c is a number greater than or equal to 0, d is a number greater than or equal to 0, and a+b+c+d is 2≤a+b+c+d≤500, [Chemical formula 2] In formula (2) and formula (3), R 2 and R 3 are independently a hydrogen atom or a straight-chain alkyl group having 1 to 10 carbon atoms, and the dotted line represents an atomic bond. (B) an organopolysiloxane containing a maleimide group, represented by the following formula (4), having a number average molecular weight of 500 to 40,000, [Chemical formula 3] In formula (4), R 4 are independently a monovalent hydrocarbon group having 1 to 10 carbon atoms or a maleimide group represented by the following formula (5), and R 4 Two or more of them are maleimide groups represented by the following formula (5), e is a number greater than or equal to 2, f is a number greater than or equal to 0, g is a number greater than or equal to 0, h is a number greater than or equal to 0, and e+f+g+h is 2≤e+f+g+h≤500, [Chemical formula 4] In formula (5), R 5 are independently hydrogen atoms or methyl groups, and dotted lines represent atomic bonds.

2. The curable silicone resin composition according to claim 1, in, Both or either of d in Formula (1) and h in Formula (4) is 0.

3. The curable silicone resin composition according to claim 1, in, Both or either of c in formula (1) and g in formula (4) is 0.

4. The curable silicone resin composition according to claim 1, in, c and d in formula (1) and g and h in formula (4) are all 0.

5. A method for recycling a curable silicone resin composition, in, The method comprises the step of heating the cured product of the curable silicone resin composition according to any one of claims 1 to 4 to 130°C or higher.

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