A biphenyl-type polysulfydryl compound, a preparation method and application thereof

Abstract

The application discloses a biphenyl polysulfydryl compound and a preparation method and application thereof, and the biphenyl polysulfydryl compound has a general structural formula as shown in the following formula: wherein R 1 and R 2 are adjacent substituents on a benzene ring, R 1 is a mercaptopropyl group, R 2 is a mercaptoalkoxy group with C2-C18, f 1 m and f 2 n are other substituents on the benzene ring, f 1 and f 2 are independently selected from any group except for an organometallic group and a nucleophilic group, and m and n are independently selected from any integer from 0 to 3. The biphenyl polysulfydryl compound with mercaptoalkyl and mercaptoalkoxy groups adjacent to each other is prepared from a low-cost raw material biphenyl diol, the preparation method is simple, efficient, controllable and low in cost, and is suitable for batch preparation. The biphenyl polysulfydryl compound with adjacent substituents can not only realize low-temperature curing of a resin composition, but also can significantly improve the bonding strength, moisture and heat resistance, mechanical properties and waterproof performance of the resin after curing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic synthesis, in particular to a biphenyl polysulfide compound and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of the electronic industry, the performance requirements of electronic packaging materials are becoming higher and higher. Common resins are generally liquid or semi-solid at room temperature and need to be converted to solid state through a curing process. The curing agent is a key component that promotes the transition of epoxy resin from liquid to solid, and its type and performance directly affect the performance of the final cured product. Polysulfide compounds have multiple mercapto groups, which can react with epoxy groups or unsaturated groups in the resin to form thioether bonds. Due to its unique chemical structure and reactivity, this type of thiol curing agent can react with epoxy resin at low temperature to form a stable three-dimensional network structure.

[0003] In the electronic packaging process, low-temperature curing technology can reduce thermal stress, protect sensitive electronic components, and reduce energy consumption. In addition, low-temperature curing can also shorten the production cycle and improve production efficiency. Although existing thiol curing agents have advantages in low-temperature curing, their insufficient heat resistance and moisture resistance limit their application in high-performance electronic packaging. In addition, in the manufacturing of electronic products, low-water absorption adhesive can be used to bond electronic components and circuit boards, and the bonded electronic components and circuit boards are less likely to short circuit and damage in a humid environment, thereby improving the reliability and safety of electronic products. Based on the demand for waterproof, insulating and other functions of electronic products, the toughness of electronic packaging materials is required to be high to avoid the failure of sealing due to the cracking or delamination of the packaging material under external stress, thereby affecting the service life of electronic products.

[0004] Therefore, there is an urgent need for a curing agent that can be used not only for low-temperature curing of resins, but also for resins cured by the curing agent to have good moisture resistance, low water absorption, and toughness, which can be used to prepare adhesives or sealants for electronic products to improve the reliability and safety of electronic products. SUMMARY

[0005] To solve the above problems, the present application provides a biphenyl polysulfide compound and a preparation method and application thereof. The biphenyl polysulfide compound not only contains a rigid biphenyl structure and four flexible alkyl mercapto groups, but also two alkyl mercapto groups distributed on the benzene ring are ortho. The resin cured by the compound as a curing agent not only has excellent moisture resistance, but also exhibits good mechanical properties, so that the resin composition containing the biphenyl polysulfide compound is suitable for adhesives or sealing materials for electronic products.

[0006] Specifically, the following technical solutions are provided:

[0007] The first aspect of the present application provides a biphenyl polysulfydryl compound having the general structure shown below:

[0008]

[0009] wherein R 1 and R 2 are adjacent substituents on the benzene ring, R 1 is -(CH2)3SH, R 2 is -OR 3 is -SH, R 3 is C2-C18 alkylene;

[0010] f 1 and f 2 are other substituents on the biphenyl, in addition to R 1 and R 2 , and are each independently selected from any group except organometallic groups and nucleophilic groups; m and n are each independently selected from any integer from 0 to 3, i.e. f 1 and f 2 are each independently selected from any group except organometallic groups and nucleophilic groups; m and n are each independently selected from any integer from 0 to 3, i.e. f 1 m represents m substituents f 1 replacing hydrogens on the biphenyl, f 2 n represents n substituents f 2 replacing hydrogens on the biphenyl;

[0011] when f 1 is at position 1 and / or position 2 of the biphenyl, f 1 is selected from H, F, Cl, methyl, and trifluoromethyl;

[0012] when f 2 is at position 3 and / or position 4 of the biphenyl, f 2 is selected from H, F, Cl, methyl, and trifluoromethyl.

[0013] Further, the nucleophilic groups include hydroxyl, amino, carboxyl, phosphoric acid group, and the like.

[0014] Further, f 1 and f 2 are each independently selected from one or more of H, F, Cl, alkyl, and halogenated alkyl.

[0015] Further, the biphenyl polysulfydryl compound has the structure shown in formula (I) to formula (III):

[0016]

[0017] wherein R is a C2-C18 alkylene group. 3 wherein R is a C2-C18 alkylene group.

[0018] Further, the biphenyl polythiol compound is

[0019] The second aspect of the present application provides a preparation method of the biphenyl polythiol compound of the first aspect, comprising the following steps:

[0020] S1, reacting a biphenyl diol compound of formula a and a compound of formula b in the presence of a first base reagent, a first phase transfer catalyst and a first solvent to obtain a first intermediate product of formula c;

[0021] S2, heating the first intermediate product to obtain a second intermediate product of formula d;

[0022] S3, reacting the second intermediate product and a compound of formula e in the presence of a second base reagent, a second phase transfer catalyst and a second solvent to obtain a third intermediate product of formula f;

[0023] S4, reacting the third intermediate product and thioacetic acid in the presence of a free radical initiator and a third solvent to obtain a fourth intermediate product of formula g;

[0024] S5, reacting the fourth intermediate product with an acid reagent in the presence of a fourth solvent to obtain the biphenyl polythiol compound;

[0025] The structures of the above formula a-g are as follows:

[0026]

[0027] wherein X is bromine or chlorine;

[0028] l is selected from any integer from 0 to 16.

[0029] Further, the protective atmosphere includes but is not limited to nitrogen.

[0030] Further, in S1, the first base reagent is selected from one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, and p-dimethylaminopyridine; in some preferred embodiments, the first base reagent is potassium carbonate, potassium hydroxide or sodium hydroxide.

[0031] Further, in S1, the first phase transfer catalyst is selected from one or more of crown ether, onium salt, ammonium salt, sulfonium salt, arsenic salt, polyether, acyclic polyether and tertiary amine catalyst; in some preferred embodiments, the first phase transfer catalyst is 18-crown-6, triethylamine or tetrabutylammonium bromide.

[0032] Further, in S1, the first solvent is selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, methanol; in some preferred embodiments, the first solvent is acetone, ethyl acetate or dichloromethane.

[0033] Further, in S1, the temperature of the reaction is preferably 60-90 °C, and the time of the reaction is preferably 6-15 h.

[0034] Further, in S2, the temperature of the heating reaction is preferably 150-250 °C, and the time of the heating reaction is preferably 10-18 h.

[0035] Further, in S3, the second base reagent is selected from one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, p-dimethylaminopyridine; in some preferred embodiments, the second base reagent is potassium carbonate, potassium hydroxide or sodium hydroxide.

[0036] Further, in S3, the second phase transfer catalyst is selected from one or more of crown ether, onium salt, ammonium salt, sulfonium salt, arsenic salt, polyether, acyclic polyether and tertiary amine catalyst; in some preferred embodiments, the second phase transfer catalyst is 18-crown-6, triethylamine or tetrabutylammonium bromide.

[0037] Further, in S3, the second solvent is selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, methanol; in some preferred embodiments, the second solvent is acetone, ethyl acetate or dichloromethane.

[0038] Further, in S3, the temperature of the reaction is 60-90 °C, and the time of the reaction is 6-15 h.

[0039] Further, in S4, the radical initiator is selected from one or more of azo, organic peroxide and oxidation-reduction initiator; in some preferred embodiments, the radical initiator is azobisisobutyronitrile or benzoyl peroxide.

[0040] Further, in S4, the third solvent is selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, methanol; in some preferred embodiments, the third solvent is tetrahydrofuran or N,N'-dimethylformamide.

[0041] Further, in S4, the temperature of the reaction is preferably 60-90 °C, and the time of the reaction is preferably 15-25 h.

[0042] Further, in S5, the acid reagent includes, but is not limited to, hydrochloric acid, sulfuric acid, etc., to promote the hydrolysis of the ester bond, preferably, the concentration of the acid reagent in the reaction system is preferably 0.8-1.3 mol / L.

[0043] Further, in S5, the fourth solvent is selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, and methanol; in some preferred embodiments, the fourth solvent is a mixed solvent of tetrahydrofuran / methanol (volume ratio 1:1) or a mixed solvent of N,N'-dimethylformamide / methanol (volume ratio 1:1).

[0044] Further, the temperature of the reaction is preferably 55-95℃, and the reaction time is preferably 25-40h.

[0045] The third aspect of the present application provides a resin composition comprising a resin and a curing agent, wherein the curing agent comprises the biphenyl-type polysulfydryl compound of the first aspect; and the resin comprises one or more of an epoxy resin, a photosensitive resin, a benzaldehyde compound, an olefin compound having a carbon-carbon double bond in the molecule, and an acrylate compound.

[0046] Further, the resin composition further comprises a curing accelerator, when the resin is an epoxy resin, the curing accelerator is an amine, such as PN23; when the resin is a combination of an epoxy resin and a photosensitive resin, the curing accelerator is a free radical photoinitiator and an amine, such as (2,4,6-trimethylbenzoyl)diphenylphosphine oxide and PN23; when the resin is a benzaldehyde compound, the curing accelerator is trifluoroacetic acid; when the resin is an olefin compound having a carbon-carbon double bond in the molecule or an acrylate compound, the curing accelerator is a free radical photoinitiator, such as 2,2-dimethoxy-2-phenylacetophenone.

[0047] The fourth aspect of the present application provides the use of the resin composition of the third aspect in the preparation of an adhesive or a sealant.

[0048] Compared with the prior art, the present application has the following beneficial effects:

[0049] The present application provides a biphenyl-type polysulfydryl compound, which comprises a rigid biphenyl structure and four flexible alkyl mercapto groups in the molecule, and the two alkyl mercapto groups distributed on the benzene ring are ortho. The biphenyl structure endows the cured resin with good heat resistance, and the four mercapto groups with specific position structure can further improve the heat resistance of the cured resin through high crosslinking density, and significantly improve the toughness of the cured resin. In addition, the biphenyl-type polysulfydryl compound is in liquid state at room temperature, has low viscosity, and can be directly used as a curing agent in the curing process of the resin composition.

[0050] The application provides a method for preparing a biphenyl type polysulfydryl compound at low cost, and the biphenyl type polysulfydryl compound is prepared from biphenyl diol as raw material, and the cost of solvents, catalysts and other raw materials in the synthesis process is low, so that the biphenyl type polysulfydryl compound is prepared at low cost, for example, the cost of 4,4'-bis(3-mercapto propoxy)-3,3'-bis(3-mercapto propyl) biphenyl is only 3.5 yuan / g (the cost can be further reduced in batch production), which is more than 43 yuan / g compared with the cost of starting material (5,5'-diallyl-2,2'-biphenyl diol, 68 yuan / g) required for preparing 5,5'-bis(3-mercapto propyl)-2,2'-bis(3-mercapto propoxy) biphenyl in the prior art, so that the preparation cost of the biphenyl type polysulfydryl compound is greatly reduced; in addition, the method has simple and efficient synthesis steps, and has high controllability and high yield of target product, and is suitable for batch production.

[0051] The biphenyl type polysulfydryl compound provided by the application is used as a curing agent in a resin composition, so that the resin composition can be rapidly cured under low temperature conditions, and the internal stress and shrinkage degree generated during curing are small; meanwhile, the curing agent has high functionality and does not have a hydrolyzable group, so that the resin composition containing the curing agent has high crosslinking density and is not easy to hydrolyze after curing, thereby significantly improving the bonding strength, heat resistance and humidity resistance, toughness and the like of the cured resin. Compared with the biphenyl type polysulfydryl compound substituted by a mercaptoalkyl group and a mercaptoalkoxy group at ortho positions, the resin composition prepared by using the biphenyl type polysulfydryl compound substituted by a mercaptoalkyl group and a mercaptoalkoxy group at ortho positions as a curing agent has better bonding strength, heat resistance and humidity resistance, toughness and low water absorption after curing, and is more suitable for preparing adhesives, sealing materials and the like for electronic products. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 A real picture of 4,4'-bis(3-mercapto propoxy)-3,3'-bis(3-mercapto propyl) biphenyl prepared in Example 1;

[0053] Figure 2 An H-NMR chart of 4,4'-bis(3-mercapto propoxy)-3,3'-bis(3-mercapto propyl) biphenyl prepared in Example 1; 1 An H-NMR chart;

[0054] Figure 3 A C-NMR chart of 4,4'-bis(3-mercapto propoxy)-3,3'-bis(3-mercapto propyl) biphenyl prepared in Example 1; 13 A C-NMR chart;

[0055] Figure 4 An IR spectrum chart of 4,4'-bis(3-mercapto propoxy)-3,3'-bis(3-mercapto propyl) biphenyl prepared in Example 1. DETAILED DESCRIPTION

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0057] The present application is further described by the following examples and comparative examples, which do not limit the scope of the application.

[0058] The following examples and comparative examples employed some of the raw materials as follows:

[0059]

[0060] Example 1

[0061] This example provides a preparation of a diphenyl polysulfide compound 4,4'-bis(3- mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)diphenyl, and the specific preparation method is as follows:

[0062] (1) 18.6 g of 4,4'-dihydroxydiphenyl and 36.3 g of allyl bromide were dissolved in 250 mL of acetone, then 55.3 g of anhydrous potassium carbonate and 2.6 g of 18-crown-6 were added, and the reaction was stirred at 70°C under N2protection for 12 h. After filtration, the solvent and excess raw materials in the filtrate were removed by distillation under reduced pressure, and after water washing and drying, the first intermediate product was obtained with a yield of 94%;

[0063] (2) 26.6 g of the first intermediate product was heated to 200°C under N2protection for 13 h, and the second intermediate product was obtained by purification with a yield of 84%;

[0064] (3) 26.6 g of the second intermediate product and 36.3 g of allyl bromide were dissolved in 250 mL of acetone, and 55.3 g of anhydrous potassium carbonate and 2.6 g of 18-crown-6 were added. The reaction was stirred at 70°C under N2protection for 10 h. After filtration, the solvent and excess raw materials in the filtrate were removed by distillation under reduced pressure, and after water washing and drying, the third intermediate product was obtained with a yield of 89%;

[0065] (4) 34.7 g of the third intermediate product and 45.7 g of thioacetic acid were dissolved in 300 mL of tetrahydrofuran, 3.3 g of azobisisobutyronitrile was added, and then the reaction was stirred at 65°C for 16 h under N2 protection. After filtration, the solvent and excess raw materials in the filtrate were removed by distillation under reduced pressure, and then the product was dried after water washing, to obtain the fourth intermediate product, with a yield of 80%;

[0066] (5) 65.1 g of the fourth intermediate product and 10 g of concentrated hydrochloric acid were dissolved in 150 mL of tetrahydrofuran and 150 mL of methanol, and then the reaction was stirred at 65°C for 33 h under N2 protection. After filtration, the solvent and excess raw materials in the filtrate were removed by distillation under reduced pressure, and then the product was dried after water washing, to obtain 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl.

[0067] The product prepared in this example is liquid at room temperature, has a low viscosity, and has a structure as shown in Figure 1 The nuclear magnetic hydrogen spectrum, carbon spectrum and infrared spectrum of the product are shown in Figures 2-4 respectively, and 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl is prepared.

[0068] Example 2

[0069] This example provides a thermosetting resin composition, which comprises the following components in parts by mass: bisphenol A type epoxy resin 55 parts, biphenyl type polysulfide compound 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl prepared in Example 1 40 parts, latent curing accelerator (PN23) 0.55 parts (1% of the epoxy resin).

[0070] The above raw materials were uniformly mixed at room temperature, and then subjected to a degassing treatment. The product was discharged and packaged into a sealed rubber tube, to obtain the resin composition.

[0071] Example 3

[0072] This example provides a photocuring resin composition, which comprises the following components in parts by mass: triallyl isocyanurate 35 parts, biphenyl type polysulfide compound 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl prepared in Example 1 50 parts, and 2,2-dimethoxy-2-phenylphenylacetophenone 0.7 parts (2% of the UV resin).

[0073] The above raw materials were uniformly mixed at room temperature and in the dark, and then subjected to a degassing treatment. The product was discharged and packaged into a black or brown sealed rubber tube, to obtain the resin composition.

[0074] Example 4

[0075] The present embodiment provides a photo-thermal dual-curing resin composition, which comprises the following components by mass fraction:

[0076] Bisphenol A type epoxy resin 55 parts, tricyclodecane dimethanol diacrylate resin 40 parts, biphenyl type polysulfide compound 4, 4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl 40 parts prepared in Example 1, latent curing agent (PN23) 0.55 parts, (2,4,6-trimethylbenzoyl) diphenyl phosphine oxide 0.8 parts (2% of the photosensitive resin).

[0077] The above raw materials are mixed uniformly under light shielding and normal temperature conditions, and then subjected to defoaming treatment. The product is discharged and packaged in black or brown airtight rubber tubes to obtain the resin composition.

[0078] Example 5

[0079] The present embodiment provides a room temperature curing resin composition, which comprises the following components by mass fraction: Component A comprises 4-hydroxy-3-methoxy benzaldehyde 20 parts, trifluoroacetic acid 2.6 parts (13% of the benzaldehyde resin), and Component B comprises biphenyl type polysulfide compound 4, 4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl 50 parts prepared in Example 1.

[0080] The raw materials of Components A and B are mixed uniformly under normal temperature conditions, and then subjected to defoaming treatment. The product is discharged and packaged in airtight A and B double tubes to obtain the resin composition.

[0081] Comparative Example 1

[0082] The present comparative example provides a thermal curing resin composition, which is different from Example 2 only in that an equal amount of commercial polysulfide curing agent tetra(3-mercaptopropionic acid) pentaerythritol ester is used instead of biphenyl type polysulfide compound 4, 4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl, and the rest is consistent. The resin composition is prepared.

[0083] Comparative Example 2

[0084] The present comparative example provides a photo-curing resin composition, which is different from Example 3 only in that an equal amount of commercial polysulfide curing agent tetra(3-mercaptopropionic acid) pentaerythritol ester is used instead of biphenyl type polysulfide compound 4, 4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl, and the rest is consistent. The resin composition is prepared.

[0085] Comparative Example 3

[0086] The comparative example provides a photo-thermal dual-curing resin composition, which is identical to that of Example 4 except that an equal amount of a commercial polythiol curing agent tetra(3-mercaptopropionic acid) pentaerythritol ester is used instead of the biphenyl-type polythiol compound 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl, and the rest is consistent.

[0087] Comparative Example 4

[0088] The comparative example provides a room temperature curing resin composition, which is identical to that of Example 5 except that an equal amount of a commercial polythiol curing agent tetra(3-mercaptopropionic acid) pentaerythritol ester is used instead of the biphenyl-type polythiol compound 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl, and the rest is consistent, to prepare the resin composition.

[0089] Comparative Example 5

[0090] The comparative example provides a thermal curing resin composition, which is identical to that of Example 2 except that an equal amount of 5,5'-bis(3-mercaptopropyl)-2,2'-bis(3-mercaptopropoxy) biphenyl (structure: ) is used instead of the biphenyl-type polythiol compound 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl, and the rest is consistent, to prepare the resin composition.

[0091] Comparative Example 6

[0092] The comparative example provides a photo-curing resin composition, which is identical to that of Example 3 except that an equal amount of 5,5'-bis(3-mercaptopropyl)-2,2'-bis(3-mercaptopropoxy) biphenyl is used instead of the biphenyl-type polythiol compound 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl, and the rest is consistent, to prepare the resin composition.

[0093] Comparative Example 7

[0094] The comparative example provides a photo-thermal dual-curing resin composition, which is identical to that of Example 4 except that an equal amount of 5,5'-bis(3-mercaptopropyl)-2,2'-bis(3-mercaptopropoxy) biphenyl is used instead of the biphenyl-type polythiol compound 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl, and the rest is consistent, to prepare the resin composition.

[0095] Comparative Example 8

[0096] The comparative example 2 provides a room temperature curing resin composition, which is different from the example 5 only in that the same amount of 5,5'-bis(3-mercaptopropyl)-2,2'-bis(3-mercaptopropoxy)diphenyl is used instead of the diphenyl type polythiol compound 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)diphenyl, and the rest is consistent, and the resin composition is prepared.

[0097] Performance test

[0098] The resin compositions prepared in the above examples 2-5 and comparative examples 1-8 are subjected to performance test, and the details are as follows:

[0099] Curing conditions:

[0100] The resin compositions prepared in the examples 2 and comparative examples 1, 5 are extruded from the glue pipe by using a dispensing machine, and then cured at 80℃ for 60 minutes to obtain the cured samples.

[0101] The resin compositions prepared in the examples 3 and comparative examples 2, 6 are extruded from the glue pipe by using a dispensing machine, and then cured by using a ultraviolet light source (wavelength 365nm, light intensity 1000mW / cm 2 ) for 15 seconds to obtain the cured samples.

[0102] The resin compositions prepared in the examples 4 and comparative examples 3, 7 are extruded from the glue pipe by using a dispensing machine, and then cured by using a ultraviolet light source (wavelength 365nm, light intensity 1000mW / cm 2 ) for 5 seconds and then at 80℃ for 60 minutes to obtain the cured samples.

[0103] The resin compositions prepared in the examples 5 and comparative examples 4, 8 are extruded from the double tube package by using a dispensing machine, and then mixed by using a static mixer, and then cured at room temperature for 24h to obtain the cured samples.

[0104] (1) Glass transition temperature (℃): The resin compositions prepared in the above examples and comparative examples are completely cured to prepare a thin sheet with a size of 42mmx8mmx0.3mm, and the change rule of the loss factor (tanδ) with temperature is determined in the temperature range of-40-250℃ under the atmosphere of liquid nitrogen and the film stretching mode, wherein the heating rate is 10℃ / min, the test frequency is 10Hz, and the glass transition temperature T g (℃) of the cured resin composition is determined.

[0105] (2) Bonding strength (MPa) and elongation at break (%): The resin compositions prepared in the above examples and comparative examples were respectively coated on a sheet to make test samples, the bonding area was 25.4 mm x 5 mm, and the thickness of the adhesive layer was ensured to be 0.1 mm, the test samples were respectively cured, then the completely cured samples were tested by using a universal testing machine to pull the two sheets in opposite directions at an ambient temperature of 25°C, and the measured force value was recorded as strength (MPa); after the cured samples were treated under the conditions of heating and humidification 85°C / 85% RH / 750 h, the shear bonding strength (MPa) and elongation at break (%) of the samples were tested again at an ambient temperature of 25°C and recorded.

[0106] (3) Water absorption rate (%): The resin compositions prepared in the above examples and comparative examples were respectively made into block-shaped samples with a size of 20 x 10 x 5 mm, and then the test samples were respectively cured. The completely cured samples were placed in distilled water at 80°C, soaked at 80°C for 24 h, taken out and weighed, and the water absorption rate (%) was calculated.

[0107] The above test results are shown in Table 1 as follows:

[0108] Table 1

[0109]

[0110] As can be seen from Table 1, the glass transition temperature, bonding strength at room temperature, bonding strength after heating and humidification, and elongation at break after heating and humidification of the resin compositions prepared by using 4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl prepared in Example 1 as the curing agent (Examples 2-5) are all significantly higher than those of the resin compositions prepared by using commercially available pentaerythritol tetra(3-mercaptopropionate) as the curing agent (Comparative Examples 1-4, wherein Example 2 VS Comparative Example 1, Example 3 VS Comparative Example 2, Example 4 VS Comparative Example 3, and Example 5 VS Comparative Example 4).

[0111] As can be seen from Examples 2-5 and Comparative Examples 5-8, compared with tetramercaptobiphenyl substituted with mercaptoalkyl and mercaptoalkoxy at the para position, the resin composition prepared by using tetramercaptobiphenyl (4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl) substituted with mercaptoalkyl and mercaptoalkoxy at the ortho position as the curing agent has relatively low T gHowever, the resin composition prepared by using the 4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl prepared in Example 1 as the curing agent has higher room temperature bonding strength, and the bonding strength and elongation at break after heating and humidification are significantly higher than those of the resin composition cured by using 5,5'-bis(3-mercaptopropyl)-2,2'-bis(3-mercaptopropoxy) biphenyl as the curing agent, which also indicates that the resin composition prepared by using the 4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl prepared in Example 1 as the curing agent has better bonding strength, moisture resistance and toughness after curing.

[0112] In addition, according to the water absorption test results, compared with the commercial pentaerythritol tetra(3-mercaptopropionate) and the thiol alkyl and thiol alkoxy para-substituted tetramercaptobiphenyl 5,5'-bis(3-mercaptopropyl)-2,2'-bis(3-mercaptopropoxy) biphenyl, the resin composition prepared by using the 4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl) biphenyl prepared in Example 1 as the curing agent has a significantly lower water absorption rate of the sample after curing, and has better water resistance.

[0113] In summary, the biphenyl-type polysulfide compound prepared in the present application has a rigid biphenyl structure and no ester bond, is in liquid state at room temperature, has low viscosity and good processability; the resin composition prepared by using the biphenyl-type polysulfide compound can be rapidly cured at a lower temperature, and has excellent moisture resistance, toughness and water resistance after curing, and can be widely used in adhesives, coatings, sealing materials and the like.

[0114] The above-described examples are only preferred examples for fully illustrating the present application, and the protection scope of the present application is not limited thereto. Any equivalent replacement or transformation made by those skilled in the art based on the present application is within the protection scope of the present application. The protection scope of the present application is subject to the claims.

Claims

1. A resin composition, characterized by, The resin comprises one or more of an epoxy resin, a photosensitive resin, a benzaldehyde compound, and an acrylate compound, and the curing agent comprises a biphenyl polysulfide compound. The biphenyl polysulfide compound has a structure shown in formula (I): ， wherein R 3 is C2-C18 alkylene.

2. The resin composition according to claim 1, characterized by The biphenyl polysulfide compound is prepared by the following steps: S1, reacting a compound shown in formula a and a compound shown in formula b in the presence of a first base reagent, a first phase transfer catalyst, and a first solvent to obtain a first intermediate product shown in formula c; S2, heating the first intermediate product to obtain a second intermediate product shown in formula d; S3, reacting the second intermediate product and a compound shown in formula e in the presence of a second base reagent, a second phase transfer catalyst, and a second solvent to obtain a third intermediate product shown in formula f; S4, reacting the third intermediate product and thioacetic acid in the presence of a free radical initiator and a third solvent to obtain a fourth intermediate product shown in formula g; S5, reacting the fourth intermediate product with an acid reagent in the presence of a fourth solvent to obtain the biphenyl polysulfide compound; The structures of formula a-g are as follows: ， X is bromine or chlorine; l is an integer from 0 to 16.

3. The resin composition according to claim 2, characterized by In S1, the first base reagent is selected from one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, and p-dimethylaminopyridine; The first phase transfer catalyst is selected from one or more of crown ethers, onium salts, ammonium salts, sulfonium salts, arsenic salts, polyethers, acyclic polyethers, and tertiary amine catalysts; The first solvent is selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, and methanol; The reaction temperature is 60-90 ℃, and the reaction time is 6-15 h.

4. The resin composition according to claim 2, characterized by In S2, the heating reaction temperature is 150-250 ℃, and the heating reaction time is 10-18 h.

5. The resin composition according to claim 2, characterized by In S3, the second base reagent is selected from one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, and p-dimethylaminopyridine; The second phase transfer catalyst is selected from one or more of crown ethers, onium salts, ammonium salts, sulfonium salts, arsenic salts, polyethers, acyclic polyethers, and tertiary amine catalysts; The second solvent is selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, and methanol; The reaction temperature is 60-90 ℃, and the reaction time is 6-15 h.

6. The resin composition according to claim 2, characterized by In S4, the free radical initiator is selected from one or more of azo compounds, organic peroxides, and oxidation-reduction initiators; The third solvent is selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, and methanol; The reaction temperature is 60-90 ℃, and the reaction time is 15-25 h.

7. The resin composition according to claim 2, characterized by In S5, the acid reagent is hydrochloric acid and / or sulfuric acid; The fourth solvent is selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, and methanol; The temperature of the reaction is 55-95 °C, and the reaction time is 25-40 h.

8. Use of the resin composition according to any one of claims 1 to 7 for the production of an adhesive or a sealant.

Images