High-temperature-resistant low-VOC (volatile organic compound) two-component silicone structural sealant and preparation method thereof

Abstract

The invention provides a high-temperature-resistant low-VOC (volatile organic compound) two-component silicone structural sealant and a preparation method thereof. The two-component silicone structural sealant comprises a component A and a component B, wherein the volume ratio of the component A to the component B is (8-12): 1; the component A comprises the following components in parts by weight: 100 parts of an organopolysiloxane polymer, 70-120 parts of nano calcium carbonate and 3-30 parts of a plasticizer; the component B comprises 100 parts of dimethyl silicone oil, 30 parts of carbon black, 10-50 parts of a cross-linking agent oligomer, 10-40 parts of an amino coupling agent oligomer, 10-30 parts of an epoxy coupling agent oligomer and 0.1-1 part of a catalyst. The two-component silicone structural sealant can improve the series of defects of the existing two-component silicone structural sealant, realizes high temperature resistance, low VOC (volatile organic compound) and good high-temperature and high-humidity cohesiveness, can be applied to special buildings, and can meet high requirements of specific application scenes such as automobiles, electronic appliances and precise instruments and equipment.

Description

Technical Field

[0001] The invention relates to the technical field of silicone structural sealants, and in particular to a high temperature resistant and low VOC two-component silicone structural sealant and a preparation method thereof. Background Art

[0002] Two-component silicone structural sealant is a sealant with excellent bonding performance, high strength, high elongation, weathering resistance, UV resistance, ozone resistance, etc., which plays a role in structural bonding in structural assembly. However, two-component silicone structural sealant has general high temperature resistance, low tensile strength at high temperature, and poor bonding; especially in high temperature and high humidity environment, the bonding is greatly reduced and cannot meet specific needs. In addition, in some specific fields of use, there are higher requirements for volatile organic compounds (VOC).

[0003] Existing conventional two-component silicone structural sealants release small molecular by-products during the condensation reaction. At the same time, the commonly used cross-linking agents and coupling agents have low flash points and are easy to migrate, resulting in high VOC in the prepared two-component silicone structural sealants.

[0004] Therefore, based on the above-mentioned deficiencies of the two-component silicone structural sealant, the present invention proposes a two-component silicone structural sealant with high temperature resistance, low VOC and good adhesion. Summary of the invention

[0005] The invention provides a high temperature resistant low VOC two-component silicone structural sealant and a preparation method thereof, the purpose of which is to solve the problems of low high temperature bonding strength, high VOC, poor bonding, etc. of the two-component silicone structural sealant in the background technology.

[0006] In order to achieve the above-mentioned purpose, the embodiment of the present invention provides a high temperature resistant low VOC two-component silicone structural sealant and a preparation method thereof. The present invention uses specially prepared crosslinking agent oligomers and coupling agent oligomers to optimize the formula, and then cooperates with 107 glue, fillers, etc. to achieve the optimal effect of the two-component silicone structural sealant. The present invention improves a series of shortcomings of the existing two-component silicone structural sealant, and at the same time achieves high temperature resistance, low VOC, and good high temperature and high humidity adhesion. In addition to special construction applications, it can meet the high requirements of specific industrial application scenarios such as automobiles, electronic appliances, and precision instruments and equipment.

[0007] An embodiment of the present invention provides a high temperature resistant and low VOC two-component silicone structural sealant, wherein the two-component silicone structural sealant comprises a component A and a component B, and the volume ratio of the component A to the component B is 8 to 12:1;

[0008] The specific formula of the A component is, in parts by weight:

[0009] 100 parts of organopolysiloxane polymer,

[0010] 70-120 parts of nano calcium carbonate,

[0011] 3-30 parts of plasticizer;

[0012] The specific formula of the B component is, in parts by weight:

[0013]

[0014] Preferably, the crosslinking agent oligomer in the B component is selected from the following structural formula:

[0015]

[0016] Wherein, R1 is methyl, ethyl or propyl; R2 is C 1～10 R3 is methyl or ethyl; n is 3 to 8. More preferably, R2 is phenyl.

[0017] Preferably, the amino coupling agent oligomer in the B component is selected from the following structural formula:

[0018]

[0019] Among them, n is 4 to 6.

[0020] Preferably, the epoxy coupling agent oligomer in the B component is selected from the following structural formula:

[0021]

[0022] Among them, R1 is methyl or ethyl; R2 is methyl, ethyl or propyl; and n is 2-4.

[0023] Preferably, the organopolysiloxane polymer in component A is at least one of hydroxyl-terminated polydimethylsiloxane and alkoxy-terminated polydimethylsiloxane, has a viscosity of 3000 to 100000 mPa·s at 25° C., and has a low volatility component content of less than 0.25%.

[0024] Preferably, the nano calcium carbonate in the A component is a cubic crystal with a particle size of 60±20 nm, and does not contain small molecule oils after being surface treated with pure stearic acid.

[0025] Preferably, the plasticizer in the component A is at least one of dimethyl silicone oil, methylphenyl silicone oil and hydroxy silicone oil, with a viscosity of 100 to 1000 mPa·s at 25° C. and a low volatile matter content of less than 0.2%.

[0026] Preferably, the viscosity of the dimethyl silicone oil in the component B is 1000-20000 mPa·s at 25°C.

[0027] Preferably, the catalyst in the B component is at least one of dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate or stannous octoate.

[0028] Based on a general concept of the invention, an embodiment of the present invention provides a method for preparing the above-mentioned high temperature resistant low VOC two-component silicone structural sealant, comprising the following steps:

[0029] S1: adding the organopolysiloxane polymer, nano calcium carbonate and plasticizer into a planetary mixer according to the proportion, controlling the reaction temperature to be 40-90° C., mixing for 30-200 min, and stirring evenly to obtain component A;

[0030] S2: Add dimethyl silicone oil, carbon black, crosslinking agent oligomer, amino coupling agent oligomer, epoxy coupling agent oligomer and catalyst into a high-speed planetary mixer according to the proportion, and stir for 5 to 120 minutes under nitrogen protection to obtain component B;

[0031] S3: Component A and component B are mixed evenly in a planetary mixer in a certain volume ratio (8-12:1) under vacuum (<-0.09MPa), and then made into H-type test pieces, which are cured according to national standard 13477.8-2002, and the tensile adhesion of the samples under different conditions is tested.

[0032] The above scheme of the present invention has the following beneficial effects:

[0033] (1) The crosslinking agent oligomer and coupling agent oligomer used in the preparation process of the two-component silicone structural sealant of the present invention greatly reduce the amount of migration and volatilization of small molecules of the auxiliary agent, and greatly reduce the VOC content, which is suitable for specific high-end applications.

[0034] (2) The crosslinking agent oligomer of the present invention has a significantly improved high temperature resistance because it contains a large amount of phenyl groups;

[0035] (3) The composite coupling agent oligomer of the present invention has more reactive groups in its structure, and its adhesion is significantly improved, especially the adhesion in high temperature and high humidity environment is better maintained. DETAILED DESCRIPTION

[0036] In order to make the technical problems to be solved, technical solutions and advantages of the present invention more clear, they are described in detail below in conjunction with specific embodiments.

[0037] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0038] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0039] The crosslinking agent oligomer, amino coupling agent oligomer and epoxy coupling agent oligomer in this article were custom-made from Shandong Sike New Materials Co., Ltd.

[0040] The "low volatility components" mentioned in this article can be tested for VOC content by the method specified in GB18583.

[0041] In view of the existing problems, the present invention provides a high temperature resistant and low VOC two-component silicone structural sealant and a preparation method thereof.

[0042] Example 1

[0043] A method for preparing a high temperature resistant and low VOC two-component silicone structural sealant comprises the following steps:

[0044] (1) 100 parts of α-ω-dihydroxy-terminated polysiloxane with a viscosity of 20,000 cp, 80 parts of nano-activated calcium carbonate, and 15 parts of hydroxy silicone oil with a viscosity of 350 cp were added to a planetary mixer and stirred uniformly to obtain component A.

[0045] (2) Add 100 parts of dimethyl silicone oil with a viscosity of 1000 cp, 30 parts of carbon black, 10 parts of crosslinking agent oligomer, 25 parts of amino coupling agent oligomer, 15 parts of epoxy coupling agent oligomer, and 1 part of stannous octoate into a high-speed planetary mixer, and stir evenly under nitrogen protection to obtain component B.

[0046] Among them, the crosslinking agent oligomer is R1 methyl, R2 octyl, R3 methyl, n=3;

[0047] Amino coupling agent oligomer is n = 4;

[0048] Epoxy coupling agent oligomer is R1 methyl, R2 methyl, n=2;

[0049] (3) Component A and component B are mixed at room temperature in a volume ratio of A:B=8:1 to obtain a two-component silicone structural sealant.

[0050] Example 2

[0051] A method for preparing a high temperature resistant and low VOC two-component silicone structural sealant comprises the following steps:

[0052] (1) 100 parts of methoxy-terminated polydimethylsiloxane with a viscosity of 100,000 cp, 70 parts of nano-activated calcium carbonate, and 30 parts of dimethyl silicone oil with a viscosity of 100 cp were added into a planetary mixer and stirred uniformly to obtain component A.

[0053] (2) Add 100 parts of dimethyl silicone oil with a viscosity of 20,000 cp, 30 parts of carbon black, 30 parts of crosslinking agent oligomer, 10 parts of amino coupling agent oligomer, 30 parts of epoxy coupling agent oligomer, and 0.5 parts of dibutyltin dioctoate into a high-speed planetary mixer, and stir evenly under nitrogen protection to obtain component B.

[0054] Among them, the crosslinking agent oligomer is R1 ethyl, R2 decyl, R3 ethyl, n=5;

[0055] Amino coupling agent oligomer is n = 6;

[0056] Epoxy coupling agent oligomer is R1 ethyl, R2 propyl, n=3;

[0057] (3) Component A and component B are mixed at room temperature in a volume ratio of A:B=10:1 to obtain a two-component silicone structural sealant.

[0058] Example 3

[0059] A method for preparing a high temperature resistant and low VOC two-component silicone structural sealant comprises the following steps:

[0060] (1) 100 parts of α-ω-dihydroxy-terminated polysiloxane with a viscosity of 3000 cp, 120 parts of nano-activated calcium carbonate, and 8 parts of methylphenyl silicone oil with a viscosity of 1000 cp were added to a planetary mixer and stirred uniformly to obtain component A.

[0061] (2) Add 100 parts of dimethyl silicone oil with a viscosity of 5000cp, 30 parts of carbon black, 50 parts of crosslinking agent oligomer, 30 parts of amino coupling agent oligomer, 10 parts of epoxy coupling agent oligomer, and 0.1 parts of dibutyltin diacetate into a high-speed planetary mixer, and stir evenly under nitrogen protection to obtain component B.

[0062] Among them, the crosslinking agent oligomer is R1 propyl, R2 phenyl, R3 methyl, n=8;

[0063] Amino coupling agent oligomer is n = 5;

[0064] Epoxy coupling agent oligomer is R1 methyl, R2 ethyl, n=4;

[0065] (3) Component A and component B are mixed at room temperature in a volume ratio of A:B=12:1 to obtain a two-component silicone structural sealant.

[0066] Example 4

[0067] A method for preparing a high temperature resistant and low VOC two-component silicone structural sealant comprises the following steps:

[0068] (1) 100 parts of α-ω-dihydroxy-terminated polysiloxane with a viscosity of 10,000 cp, 100 parts of nano-activated calcium carbonate, and 3 parts of dimethyl silicone oil with a viscosity of 500 cp were added to a planetary mixer and stirred to obtain component A.

[0069] (2) Add 100 parts of dimethyl silicone oil with a viscosity of 15000cp, 30 parts of carbon black, 40 parts of crosslinking agent oligomer, 40 parts of amino coupling agent oligomer, 20 parts of epoxy coupling agent oligomer, and 0.3 parts of dibutyl tin dilaurate into a high-speed planetary mixer, and stir evenly under nitrogen protection to obtain component B.

[0070] Among them, the crosslinking agent oligomer is R1 ethyl, R2 methyl, R3 ethyl, n=6;

[0071] Amino coupling agent oligomer is n = 4;

[0072] Epoxy coupling agent oligomer is R1 methyl, R2 propyl, n=4;

[0073] (3) Component A and component B are mixed at room temperature in a volume ratio of A:B=11:1 to obtain a two-component silicone structural sealant.

[0074] Example 5

[0075] The protection method of this embodiment is basically the same as that of Embodiment 3, except that the structures of the cross-linking agent oligomer, the amino coupling agent oligomer, and the epoxy coupling agent oligomer are different and the amount of the epoxy coupling agent oligomer added is 15 parts.

[0076] Among them, the crosslinking agent oligomer is R1 ethyl, R2 hexyl, R3 methyl, n=4;

[0077] Amino coupling agent oligomer is n = 4;

[0078] Epoxy coupling agent oligomer is R1 ethyl, R2 ethyl, n=3.

[0079] Example 6

[0080] The protection method of this embodiment is basically the same as that of Embodiment 3, except that the structures of the crosslinking agent oligomer, the amino coupling agent oligomer, and the epoxy coupling agent oligomer are different and the amount of the amino coupling agent oligomer added is 25 parts.

[0081] Among them, the crosslinking agent oligomer is R1 propyl, R2 butyl, R3 methyl, n=6;

[0082] Amino coupling agent oligomer is n = 5;

[0083] Epoxy coupling agent oligomer is R1 is methyl, R2 is propyl, and n=2.

[0084] Example 7

[0085] The protection method of this embodiment is basically the same as that of Embodiment 3, except that the structures of the crosslinking agent oligomer, the amino coupling agent oligomer, and the epoxy coupling agent oligomer are different and the amount of the crosslinking agent oligomer added is 30 parts.

[0086] Among them, the crosslinking agent oligomer is R1 methyl, R2 nonyl, R3 ethyl, n=7;

[0087] Amino coupling agent oligomer is n = 6;

[0088] Epoxy coupling agent oligomer is R1 ethyl, R2 methyl, n=4.

[0089] Example 8

[0090] The protection method of this embodiment is basically the same as that of Embodiment 3, except that the structures of the crosslinking agent oligomer, the amino coupling agent oligomer, and the epoxy coupling agent oligomer are different and the amount of the crosslinking agent oligomer added is 40 parts.

[0091] Among them, the crosslinking agent oligomer is R1 ethyl, R2 ethyl, R3 methyl, n=5;

[0092] Amino coupling agent oligomer is n = 5;

[0093] Epoxy coupling agent oligomer is R1 methyl, R2 methyl, n=3.

[0094] Comparative Example 1

[0095] Steps (1) and (3) are the same as those in Example 4, except that in step (2),

[0096] (2) 100 parts of dimethyl silicone oil with a viscosity of 15000cp, 30 parts of carbon black, 40 parts of phenyltrimethoxysilane, 40 parts of amino coupling agent oligomer (n=4), 20 parts of γ-glycidyloxypropyltrimethoxysilane, and 0.3 parts of dibutyltin dilaurate were added into a high-speed planetary mixer and stirred evenly under nitrogen protection to obtain component B.

[0097] Comparative Example 2

[0098] Steps (1) and (3) are the same as those in Example 4, except for the following step (2);

[0099] (2) 100 parts of dimethyl silicone oil with a viscosity of 15000cp, 30 parts of carbon black, 40 parts of methyltrimethoxysilane, 40 parts of aminopropyltrimethoxysilane, 20 parts of γ-glycidyloxypropyltrimethoxysilane, and 0.3 parts of dibutyltin dilaurate were added into a high-speed planetary mixer and stirred evenly under nitrogen protection to obtain component B.

[0100] Comparative Example 3

[0101] Steps (1) and (3) are the same as those in Example 4, except for the following step (2);

[0102] (2) 100 parts of dimethyl silicone oil with a viscosity of 15000cp, 30 parts of carbon black, 40 parts of phenyltrimethoxysilane, 40 parts of KH792-, 20 parts of γ-glycidyloxypropyltrimethoxysilane, and 0.3 parts of dibutyltin dilaurate were added into a high-speed planetary mixer and stirred evenly under nitrogen protection to obtain component B.

[0103] Comparative Example 4

[0104] Steps (1) and (3) are the same as those in Example 4, except for the following step (2);

[0105] (2) 100 parts of dimethyl silicone oil with a viscosity of 15000cp, 30 parts of carbon black, 10 parts of phenyltrimethoxysilane, 20 parts of KH792-, 20 parts of γ-glycidyloxypropyltrimethoxysilane, and 0.3 parts of dibutyltin dilaurate were added into a high-speed planetary mixer and stirred evenly under nitrogen protection to obtain component B.

[0106] Comparative Example 5

[0107] The difference between this comparative example and Example 4 is that the crosslinking agent is phenyltrimethoxysilane, and the other steps and parameters are the same as those of Example 4.

[0108] Comparative Example 6

[0109] The difference between this comparative example and Example 4 is that the amino coupling agent is KH792, and the other steps and parameters are the same as those of Example 4.

[0110] Comparative Example 7

[0111] The difference between this comparative example and Example 4 is that the epoxy coupling agent is γ-glycidyloxypropyltrimethoxysilane, and the other steps and parameters are the same as those in Example 4.

[0112] Performance Testing

[0113] The silicone structural sealants prepared in the above examples and comparative examples were subjected to the following tests, and the specific results are shown in Table 1 below;

[0114] (1) For H-type specimens, after curing according to standard JG / T 475, the tensile strength and adhesion of the specimens were tested at 100°C for 24 hours and maintained at 100°C.

[0115] (2) Apply glue to fluorocarbon sprayed aluminum and after curing according to national standard 13477.8-2002, evaluate the adhesion under the conditions of 85°C and 85% RH. Take samples every day to check the adhesion and obtain the number of days to adhesion failure, i.e. the double 85 resistance adhesion.

[0116] (3) Take samples and test VOC content according to GB18583.

[0117] Table 1

[0118]

[0119]

[0120] As can be seen from Table 1 above, compared with Comparative Examples 1 to 7, the two-component silicone structural sealant of the present invention has the characteristics of high tensile strength at high temperature, low VOC, high temperature and high humidity adhesion, etc. The two-component silicone structural sealant of the present invention greatly improves the material performance through the synergistic effect between the components, solves the shortcomings of the existing two-component silicone structural sealant series, and achieves high temperature resistance, low VOC, and good high temperature and high humidity adhesion. In addition to special construction applications, it can meet the high requirements of specific application scenarios such as automobiles, electronic appliances, and precision instruments and equipment.

[0121] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high temperature resistant and low VOC two-component silicone structural sealant, characterized in that: The two-component silicone structural sealant comprises component A and component B, and the volume ratio of component A to component B is 8 to 12:1; The specific formula of the A component is, in parts by weight: 100 parts of organopolysiloxane polymer, 70-120 parts of nano calcium carbonate, 3-30 parts of plasticizer; The specific formula of the B component is, in parts by weight:

2. A high temperature resistant low VOC two-component silicone structural sealant according to claim 1, characterized in that: The crosslinking agent oligomer in the B component is selected from the following structural formula: Wherein, R1 is methyl, ethyl or propyl; R2 is C 1～10 an alkane or a phenyl group; R3 is a methyl group or an ethyl group; and n is 3 to 8.

3. The high temperature resistant and low VOC two-component silicone structural sealant according to claim 1, characterized in that: The amino coupling agent oligomer in the B component is selected from the following structural formula: Among them, n is 4 to 6.

4. The high temperature resistant and low VOC two-component silicone structural sealant according to claim 1, characterized in that: The epoxy coupling agent oligomer in the B component is selected from the following structural formula: Among them, R1 is methyl or ethyl; R2 is methyl, ethyl or propyl; and n is 2-4.

5. The high temperature resistant and low VOC two-component silicone structural sealant according to claim 2, characterized in that: The R2 is phenyl.

6. The high temperature resistant and low VOC two-component silicone structural sealant according to claim 1, characterized in that: The organopolysiloxane polymer in the component A is at least one of hydroxyl-terminated polydimethylsiloxane and alkoxy-terminated polydimethylsiloxane, has a viscosity of 3000 to 100000 mPa·s at 25° C., and has a low volatility component content of less than 0.25%.

7. The high temperature resistant and low VOC two-component silicone structural sealant according to claim 1, characterized in that: The nano calcium carbonate in the A component is a cubic crystal with a particle size of 60±20 nm, and does not contain small molecule oil after being surface treated with pure stearic acid.

8. The high temperature resistant and low VOC two-component silicone structural sealant according to claim 1, characterized in that: The plasticizer in the component A is at least one of dimethyl silicone oil, methylphenyl silicone oil and hydroxy silicone oil, with a viscosity of 100 to 1000 mPa·s at 25° C. and a low volatile matter content of less than 0.2%.

9. The high temperature resistant and low VOC two-component silicone structural sealant according to claim 1, characterized in that: The viscosity of the dimethyl silicone oil in the B component is 1000-20000 mPa·s at 25° C.; the catalyst in the B component is at least one of dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate or stannous octoate.

10. A method for preparing a high temperature resistant low VOC two-component silicone structural sealant according to any one of claims 1 to 9, characterized in that: The steps include: S1: adding the organopolysiloxane polymer, nano calcium carbonate and plasticizer into a planetary mixer according to a proportion, and stirring evenly to obtain component A; S2: Add dimethyl silicone oil, carbon black, crosslinking agent oligomer, amino coupling agent oligomer, epoxy coupling agent oligomer and catalyst into a high-speed planetary mixer, and stir evenly under nitrogen protection to obtain component B; S3: Component A and component B are mixed evenly in a planetary mixer under vacuum (<-0.09MPa) to obtain.

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