A flexible, yellowing-resistant epoxy resin composition, and a method of preparing and using the same

Abstract

This application relates to the field of epoxy resins, and more particularly to a flexible, yellowing-resistant epoxy resin composition, its preparation method, and its application. The flexible, yellowing-resistant epoxy resin composition comprises one or more carbocyclic compounds represented by general formula (I) and one or more carbocyclic compounds represented by general formula (II); in general formulas (I) and (II): R1 and R2 are each independently selected from -H or C1-C. 20 The alkyl chain; R3 is independently selected from isocyanate compounds having two -NCO groups in the molecule; R4 is selected from polyhydroxy compounds containing -OH in the molecule. The flexible, yellowing-resistant epoxy resin composition of this application, in addition to having excellent molecular flexibility and solving the problems of warping, cracking, shrinkage, and defects caused by epoxy brittleness, can also maintain its original yellowing resistance.

Description

Technical Field

[0001] This application relates to the field of epoxy resins, and more specifically, to a flexible, yellowing-resistant epoxy resin composition, its preparation method, and its application. Background Technology

[0002] Traditionally, the gaps left after the construction of ceramic tiles, floor tiles, and wooden floors are usually filled with cement, lime, putty powder, etc. However, these materials have monotonous and unsightly colors and are prone to powdering and falling off. As people's living standards have improved, they have been gradually phased out. Epoxy grout, which has good durability and decorative effect, has emerged as a result.

[0003] The epoxy grout in the relevant technology is mainly composed of bisphenol A type epoxy resin and bisphenol F type epoxy resin, combined with aliphatic amine / licyclic amine curing agent, diluent, color paste, pigments and fillers. When using it, the construction process of the grout can be completed by applying glue, curing and removing glue.

[0004] However, due to the high brittleness and shrinkage of the epoxy resin used, and its fast reaction speed, the applicable period for construction is short, and defects, cracks, and fissures are prone to occur after the adhesive is removed.

[0005] While existing literature has attempted to toughen epoxy resins, the common approach involves pre-curing a portion of the epoxy resin with a curing agent. This does not alter the cross-linking of the cured epoxy, resulting in insufficient toughening and increased susceptibility to yellowing, which severely impacts the sensory experience. Therefore, this paper provides a flexible, yellowing-resistant epoxy resin composition, its preparation method, and its application. Summary of the Invention

[0006] To improve the toughness of existing epoxy grout without affecting its yellowing resistance, this application provides a flexible, yellowing-resistant epoxy resin composition, its preparation method, and its application.

[0007] When the above-mentioned flexible and yellowing-resistant epoxy resin composition is applied to tile grout, in addition to having the advantage of a long working period, it is also less prone to defects, cracks and fissures after the adhesive is removed.

[0008] In a first aspect, this application provides a flexible, yellowing-resistant epoxy resin composition, which adopts the following technical solution: a flexible, yellowing-resistant epoxy resin composition, comprising one or more carbocyclic compounds represented by general formula (I) and one or more carbocyclic compounds represented by general formula (II);

[0009]

[0010]

[0011] In general formulas (I) and (II):

[0012] R1 and R2 are independently selected from -H and C1-C, respectively. 20 Alkyl groups;

[0013] R3 are each independently selected from isocyanate compounds having two -NCO groups in their molecules;

[0014] R4 is selected from polyhydroxy compounds containing -OH.

[0015] Preferably, the isocyanate compound having two -NCO groups in the molecule of R3 is selected from one or more of 1,6-tetramethylene diisocyanate, 1,4-cyclohexyl diisocyanate, isophorone diisocyanate, methylcyclohexyl diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and isophthalic acid diisocyanate.

[0016] Preferably, the linear polyhydroxy compound in R4 is selected from one of polyethylene oxide, polypropylene oxide, polyoxyhexacyclic butane, polytetrahydrofuran, propylene oxide, and ethylene oxide copolymers.

[0017] Secondly, this application provides a method for preparing a flexible, yellowing-resistant epoxy resin composition, using the following technical solution:

[0018] A method for preparing a flexible, yellowing-resistant epoxy resin composition includes the following steps:

[0019] S1. Weigh the carbocyclic compound represented by general formula (I), heat it to 110-125℃, remove water under vacuum, and then cool it naturally to room temperature under nitrogen protection for later use.

[0020] S2. Weigh the polyether-type polyhydroxy compound, heat it to 110-120℃, remove water under vacuum, and then cool it naturally to 50-60℃ under nitrogen protection.

[0021] First, add the catalyst, then add the isocyanate compound with two -NCO groups from R3 dropwise in stages, and react at a reaction temperature of 40-70℃ for 1.5-4.0h until the NCO content is stable, thus obtaining the polyether-type polyhydroxy compound modified isocyanate intermediate.

[0022] S3. The carbocyclic compound represented by general formula (I) after treatment in S1 is added in batches to the polyether-type polyhydroxy compound modified isocyanate intermediate obtained in S2 under nitrogen protection. After the addition is complete, a catalyst is added, the temperature is raised to 80-120℃ and the reaction continues for 1-6 hours. After the NCO content is titrated to be O, the reaction continues for 1-2 hours. The product is then discharged to obtain a flexible epoxy resin composition resistant to yellowing.

[0023] Preferably, the mass ratio of the polyether-type polyhydroxy compound in S2, the catalyst, and the isocyanate compound with two -NCO groups in R3 is 100:(0.001-3):(1-45).

[0024] Preferably, the method for stepwise addition of the isocyanate compound in S2 is as follows:

[0025] First-stage addition: First, maintain the internal temperature at 50±10℃, add 5-15 parts by mass of isocyanate compound, stir for 10-30 minutes, and then raise the temperature to 60±10℃.

[0026] Secondary addition: Continue to add 10-30 parts by mass of isocyanate compound. After the addition is complete, continue to keep warm for 1-3 hours until the NCO content is stable and unchanged, thus obtaining the polyether-type polyhydroxy compound modified isocyanate intermediate.

[0027] Preferably, the mass ratio of the carbocyclic compound represented by general formula (I), the polyether-type polyhydroxy compound modified isocyanate intermediate, and the catalyst after dehydration and drying in S3 is 100:(10-60):(0.001-3).

[0028] Preferably, the method for adding in batches in S3 is as follows:

[0029] First batch feeding: First, add the first batch at 50±10℃ and stir for 30 minutes;

[0030] Secondary feeding: After the temperature rises to 70±10℃, add the second batch and continue stirring for 30 minutes;

[0031] Three-stage feeding: Once the temperature reaches 90±10, add the third batch to complete the feeding process;

[0032] Then, continue the reaction at 80-120℃ for 1-6 hours until the NCO content is determined to be O. Continue to keep warm for 1-3 hours, then discharge the material to obtain a flexible, yellowing-resistant epoxy resin composition.

[0033] Thirdly, this application provides the application of a flexible, yellowing-resistant epoxy resin composition in adhesives, sealants, potting compounds, chip encapsulation, LED encapsulation, composite materials, coatings, epoxy grout, stone adhesives, topcoats, and decorative adhesives, with a dosage of 10-100%.

[0034] Preferably, the epoxy grout further includes 5-100% curing agent;

[0035] The curing agent is one or more of aliphatic amines, cycloaliphatic amines, modified amines, and polyether amines.

[0036] In summary, this application has the following beneficial effects:

[0037] 1. The flexible, yellowing-resistant epoxy resin composition of this application significantly enhances the toughness of the carbocyclic epoxy resin by introducing specific R groups such as isocyanate compounds having two -NCO groups and linear polyhydroxy compounds having two -OH groups.

[0038] In addition, the resin composition obtained by the above modification method will not affect the original UV yellowing resistance of the resin matrix. It still has good refractive properties. After UV aging, the strength retention rate can reach 99%, and it is not easy to powder and fall off during application.

[0039] 2. The method of adding the compound represented by general formula (I) in batches in this application can effectively promote the grafting reaction between NCO and the side hydroxyl groups in the resin matrix, and generate a structure of polyether-type polyhydroxy compound isocyanate grafted with 2 molecules of epoxy, namely general formula (II), thereby achieving the purpose of toughening.

[0040] 3. In this application, the hydroxyl groups of the epoxy resin are blocked by the grafting reaction of the polyether-type polyhydroxy compound isocyanate, thereby reducing the longitudinal molecular mobility of the epoxy groups in the molecular chain segment, thus enhancing its heat resistance and yellowing resistance while maintaining its heat resistance.

[0041] Meanwhile, it was unexpectedly discovered that this grafting method did not change the main chain length of the epoxy groups. However, experiments showed that after side grafting, this modified polymer had suitable reactivity, which was beneficial in terms of extending the applicable period of construction and operation and the actual service life. It also had the advantage of low exothermic reaction, was not prone to violent reaction, and effectively avoided the phenomenon of explosive polymerization.

[0042] 4. By introducing polar amine ester bonds, this application enables the flexible yellowing-resistant epoxy resin composition to have a certain hydrogen bond adsorption effect on the substrates such as wood panels, stone, tiles, and cement to be filled when applied to grout, thereby ensuring its adhesion, tightness and service life. Attached Figure Description

[0043] Figure 1 The infrared characteristic spectrum of the compound represented by general formula (II);

[0044] Among them 2930cm -1 2860cm -1 The characteristic absorption peak of saturated CH2;

[0045] 1717cm -1 Characteristic peaks for carbonyl groups;

[0046] 1525cm -1 The characteristic absorption peak for the bending vibration of NH in the amide group;

[0047] 1239cm-1 This is the absorption peak of the stretching vibration of COC in polyether-type polyhydroxy compounds;

[0048] 1091cm -1 The characteristic absorption peak of CO ether bond;

[0049] 908cm -1 These are characteristic absorption peaks of epoxy groups;

[0050] Figure 2 Infrared characteristic spectra of each component of the flexible yellowing-resistant epoxy resin composition;

[0051] Figure 2 Curve 1 in the middle is the infrared characteristic spectrum of the compound represented by general formula (II);

[0052] Figure 2 Curve 2 is the infrared spectrum of the compound represented by general formula (I);

[0053] Figure 2 Curve 3 in the middle is the infrared spectrum of the polyether-type polyhydroxy compound. Detailed Implementation

[0054] The following are preparation examples and appendices. Figure 1-2 This application will be described in further detail as follows:

[0055] Unless otherwise specified below, the raw materials and equipment used in the preparation examples, application examples, and testing in this application are all commercially available common materials:

[0056] Isophorone diisocyanate (CAS: 4098-71-9);

[0057] Hexamethylene diisocyanate (CAS: 822-06-0);

[0058] 1,4-Cyclohexyl diisocyanate (CAS: 2556-36-7; 7517-76-2);

[0059] Methylcyclohexyl diisocyanate (CAS: 10347-54-3);

[0060] 4,4'-Dicyclohexylmethane diisocyanate (CAS: 5124-30-1);

[0061] Trimethylhexamethylene diisocyanate (CAS: 28679-16-5);

[0062] Polyhydroxy compound 1: Polypropylene oxide polyhydroxy compound (MW: 1000-5000);

[0063] Polyhydroxy compound 2: Polytetrahydrofuran polyol (MW: 1000-4000);

[0064] Polyhydroxy compound 3: Polyethylene oxide polyol (MW: 1000-5000);

[0065] The testing equipment for residual NCO bases was Fourier transform infrared spectrum (FT-IR), purchased from Thermo Fisher Scientific.

[0066] At 2270 cm⁻¹, which is a characteristic absorption band of NCO groups. -1 When the stretching vibration absorption spectrum disappears, it can be determined that there are no residual NCO groups.

[0067] Preparation Example 1

[0068] A flexible, yellowing-resistant epoxy resin composition, as described above. Figure 1-2 It is composed of carbocyclic compounds represented by general formula (I), carbocyclic compounds represented by general formula (II), and polyether-type polyhydroxy compounds;

[0069]

[0070]

[0071] It was prepared using the following process:

[0072] S1. Weigh out 337 parts of the carbocyclic compound represented by general formula (I), place it in a flask equipped with a thermometer, nitrogen protection and vacuum suction device, heat it in an oil bath to 115°C, remove water under vacuum for 1.5 hours, and then cool it naturally to room temperature under nitrogen protection for later use.

[0073] S2. Weigh out 70 parts of polyether-type polyhydroxy compound (polypropylene oxide type polyhydroxy compound with MW=2000) and place it in a flask equipped with a thermometer, nitrogen protection and vacuum suction device. Heat it in an oil bath to 115°C, remove water under vacuum for 1.5 hours, and then cool it naturally to 50°C under nitrogen protection.

[0074] First, a catalyst (dibutyltin dilaurate - 0.018 parts) was added, and then an isocyanate compound with two -NCO groups (isophorone diisocyanate - 15.6 parts) was added dropwise in stages. After the addition was completed, the reaction temperature was maintained at 50°C for 2 hours until the NCO content stabilized at 3.4%, thus obtaining a polyether-type polyhydroxy compound modified isocyanate intermediate.

[0075] That is, the mass ratio of the above-mentioned polyether-type polyhydroxy compound, the catalyst (dibutyltin dilaurate), and the isocyanate compound having two -NCO groups is 100:0.025:22.2;

[0076] The method for fractionally adding isocyanate compounds in S2 is as follows:

[0077] First-stage addition: First, keep the internal temperature at 50℃, add 5 parts by mass of isocyanate compound, stir for 20 minutes, and then raise the temperature to 60℃;

[0078] Secondary addition: Continue to add 10.6 parts by mass of isocyanate compound. After the addition is complete, continue to keep warm for 2 hours until the NCO content is 3.3% and remains stable. This yields the polyether-type polyhydroxy compound modified isocyanate intermediate.

[0079] S3. The carbocyclic compound represented by the general formula (I) after treatment in S1 is added in batches to the polyether-type polyhydroxy compound modified isocyanate intermediate obtained in S2 under nitrogen protection. After the addition is complete, 0.018 g of dibutyltin dilaurate is added, and the temperature is raised to 80°C to continue the reaction for 3 h.

[0080] After titrating the NCO content to 0, continue to keep warm and stir for 1 hour, then discharge the material to obtain a flexible, yellowing-resistant epoxy resin composition, wherein the content of the compound represented by general formula (I) is 52%, the content of the compound represented by general formula (I) is 48%, the titrated NCO content is 0%, and the infrared display shows no NCO peak.

[0081] The mass ratio of the carbocyclic compound, the polyether-type polyhydroxy compound modified isocyanate intermediate, and the catalyst represented by general formula (I) after dehydration and drying in S3 above is 100:25:0.005;

[0082] The method for adding the carbocyclic compound represented by general formula (I) in batches in S3 is as follows:

[0083] First batch feeding: Add 1 / 3 of the total amount of material to the first batch at 40℃ and stir for 30 minutes;

[0084] Secondary feeding: After the temperature rises to 60℃, add 1 / 3 of the total amount of the second batch and continue stirring for 30 minutes;

[0085] Three-stage feeding: After the temperature rises to 80℃, add 1 / 3 of the total amount of the third batch to complete the feeding process;

[0086] Then, the reaction was continued at 100℃ for 3 hours until the NCO content was titrated to O. The mixture was then kept at this temperature for another 2 hours before being discharged to obtain a flexible, yellowing-resistant epoxy resin composition.

[0087] Preparation Examples 2-6

[0088] A flexible, yellowing-resistant epoxy resin composition differs from Preparation Example 1 in that the isocyanate compound with two -NCO groups in the molecule of S2 is different, as shown in the table below:

[0089] Table: Comparison of Isocyanate Compounds with Two -NCO Groups in Preparation Examples 2-6

[0090] Group Isocyanate compounds with two -NCO groups in their molecules Preparation Example 2 Hexamethylene diisocyanate Preparation Example 3 Trimethylhexamethylene diisocyanate Preparation Example 4 Methylcyclohexyl diisocyanate Preparation Example 5 Composed of hexamethylene diisocyanate and isophorone diisocyanate in a weight ratio of 1:1 Preparation Example 6 Composed of methyl cyclohexyl diisocyanate and isophorone diisocyanate in a weight ratio of 1:1

[0091] Preparation Examples 7-11

[0092] A flexible, yellowing-resistant epoxy resin composition differs from Preparation Example 1 in that the polyether-type polyhydroxy compound used in S2 is different, as shown in the table below:

[0093] Table: Comparison of the selection of polyether-type polyhydroxy compounds in Preparation Examples 7-11

[0094] Group Polyether-type polyhydroxy compounds Preparation Example 7 Polypropylene oxide (MW:1000) Preparation Example 8 Polypropylene oxide (MW:4000) Preparation Example 9 Polyether-type polytetrahydrofuran, molecular weight 1000 Preparation Example 10 Polyether-type polytetrahydrofuran, molecular weight 2000 Preparation Example 11 Polyether-type polyethylene glycol, molecular weight 2000

[0095] Preparation Examples 12-16

[0096] A flexible, yellowing-resistant epoxy resin composition differs from Preparation Example 5 in that the proportions of each material in S2 are different, as shown in the table below:

[0097] Table: Comparison of material ratios of S2 in Preparation Examples 12-16

[0098] Group S2 material ratio (hydroxy polymer / symmetric NCO / asymmetric NCO / catalyst) Preparation Example 12 100：3：22：0.025 Preparation Example 13 100：5：20：0.025 Preparation Example 14 100：10：15：0.025 Preparation Example 15 100：15：10：0.025 Preparation Example 16 100：20：5：0.025

[0099] The aforementioned symmetrical NCO and asymmetrical NCO correspond to hexamethylene diisocyanate and isophorone diisocyanate, respectively. Furthermore, symmetrical NCO-hexamethylene diisocyanate is added via a single-stage dropwise addition, while asymmetrical NCO-isophorone diisocyanate is added via a two-stage dropwise addition.

[0100] Preparation Example 17

[0101] A flexible, yellowing-resistant epoxy resin composition differs from Preparation Example 14 in that the isocyanate compound is added dropwise in stepwise manner in S2 as follows:

[0102] First-stage addition: First, maintain the internal temperature at 50℃, add 10 parts by mass of hexamethylene diisocyanate, stir for 10-30 minutes, and then raise the temperature to 60℃;

[0103] Secondary addition: First, keep the internal temperature at 60℃, add 5 parts by mass of isophorone diisocyanate, stir for 10-30 minutes, and then raise the temperature to 70℃;

[0104] Three-stage addition: Add another 10 parts by weight of isophorone diisocyanate. After the addition is complete, keep warm for 2 hours until the NCO content is stable and unchanged, thus obtaining the polyether-type polyhydroxy compound modified isocyanate intermediate.

[0105] Preparation Example 18

[0106] A flexible, yellowing-resistant epoxy resin composition differs from Preparation Example 14 in that the isocyanate compound is added dropwise in stepwise manner in S2 as follows:

[0107] First-stage addition: First, keep the internal temperature at 50℃, add 15 parts by mass of isophorone diisocyanate, stir for 20 minutes, and then raise the temperature to 60℃.

[0108] Secondary addition: Add another 10 parts by weight of hexamethylene diisocyanate. After the addition is complete, keep warm for 2 hours until the NCO content is stable and unchanged, thus obtaining the polyether-type polyhydroxy compound modified isocyanate intermediate.

[0109] Preparation Example 19

[0110] A flexible, yellowing-resistant epoxy resin composition differs from Preparation Example 14 in that the isocyanate compound is added dropwise in stepwise manner in S2 as follows:

[0111] First-stage addition: First, maintain the internal temperature at 80℃, add 10 parts by mass of hexamethylene diisocyanate, stir for 20 minutes, and then raise the temperature to 100℃;

[0112] Secondary addition: Add another 15 parts by weight of isophorone diisocyanate. After the addition is complete, keep warm for 2 hours until the NCO content is stable and unchanged, thus obtaining the polyether-type polyhydroxy compound modified isocyanate intermediate.

[0113] Preparation Examples 20-24

[0114] A flexible, yellowing-resistant epoxy resin composition differs from Preparation Example 1 in that the proportions of each material in S2 are different, as shown in the table below:

[0115] Table: Comparison of material ratios for S3 in Preparation Examples 20-24

[0116] Group S3 material ratio Preparation Example 20 100：10：0.025 Preparation Example 21 100：15：0.025 Preparation Example 22 100：20：0.025 Preparation Example 23 100：30：0.025 Preparation Example 24 100：40：0.025

[0117] Preparation Example 25

[0118] A flexible, yellowing-resistant epoxy resin composition differs from Preparation Example 22 in that the method for batch-adding the carbocyclic compound represented by general formula (I) in S3 is as follows:

[0119] First batch feeding: First, add 1 / 4 of the total amount of material at 40℃ and stir for 30 minutes;

[0120] Secondary feeding: After the temperature rises to 60℃, add 1 / 4 of the total amount of the second batch and continue stirring for 30 minutes;

[0121] Third-stage feeding: After the temperature rises to 80℃, add 1 / 4 of the total amount of the third batch and continue stirring for 30 minutes;

[0122] Fourth-stage feeding: After the temperature rises to 100℃, add 1 / 4 of the total amount in the fourth batch to complete the feeding process;

[0123] Then, the reaction was continued at 100℃ for 3 hours until the NCO content was titrated to O. The mixture was then kept at this temperature for another 2 hours before being discharged to obtain a flexible, yellowing-resistant epoxy resin composition.

[0124] Performance testing

[0125] The epoxy grout in each application example and comparative example was taken as the test object, and then the sample was prepared according to the method in GB / T 2567. Five parallel samples of the cured product were set up for each group.

[0126] The above sample preparation conditions are: room temperature for 2 hours + 80℃ for 2 hours;

[0127] Then, its tensile strength, elongation at break, impact strength, heat resistance to yellowing, strength retention after UV irradiation, and toughness retention after UV irradiation were tested respectively. The specific test indicators and procedures are as follows:

[0128] 1) Tensile test: Samples were prepared according to the method described in GB / T 2567. Tensile tests were conducted using a universal testing machine at room temperature of 23±2℃. Tensile strength and elongation at break were measured respectively.

[0129] 2) Impact toughness test: Samples were prepared according to the method described in GB / T 2567. The impact test was conducted using a simply supported beam impact tester at room temperature of 23±2℃, and the impact strength of the samples was measured.

[0130] 3) Heat resistance and yellowing resistance: After heating and aging the cured material in an oven at 100℃ for 1 hour, it was then irradiated under a UV lamp for 23 hours. Each cycle lasted 24 hours. After 100 cycles of accelerated aging, the color change after simultaneous heat and UV aging was observed.

[0131] 4) Strength retention rate after UV irradiation: Samples were prepared according to the method described in GB / T 2567. The samples were irradiated in a UV chamber for accelerated aging. After 1000 hours, the samples were tested for strength using a universal testing machine. The ratio between the recorded data and the original data was the strength retention rate.

[0132] 5) Toughness retention rate after UV irradiation: Samples were prepared according to the method described in GB / T 2567. The samples were irradiated in a UV chamber for accelerated aging. After 1000 hours, the samples were tested on a simply supported beam impact tester. The ratio between the recorded data and the original data was the strength retention rate.

[0133] Application Example 1

[0134] An epoxy grout sealant is prepared by dispensing 100 kg of a flexible, yellowing-resistant epoxy resin composition and 25 kg of a curing agent, wherein the curing agent is DMDC and was purchased from Mitsubishi Chemical, Japan; the flexible, yellowing-resistant epoxy resin composition is prepared by Preparation Example 1.

[0135] Comparative Example 1

[0136] An epoxy grout sealant differs from Application Example 1 in that the flexible, yellowing-resistant epoxy resin composition is replaced by an equal amount of general formula (I), i.e., unmodified epoxy resin.

[0137] Comparative Example 2

[0138] An epoxy grout sealant differs from Application Example 1 in that the compound represented by general formula (I) in the corresponding preparation example is a standard bisphenol A type epoxy resin, i.e., other resins are modified.

[0139] Comparative Example 3

[0140] An epoxy grout sealant differs from Application Example 1 in that the flexible, yellowing-resistant epoxy resin composition is replaced by an equal amount of carboxyl-terminated butadiene-acrylonitrile rubber Hypro 1300X13 (CTBN) modified epoxy resin (ETBN).

[0141] The epoxy grout prepared in Application Example 1 and Comparative Examples 1-3 were sampled, and their tensile strength, elongation at break, impact strength, heat resistance to yellowing, strength retention rate after UV irradiation, and toughness retention rate after UV irradiation were tested. The average values ​​of the test results were recorded in the table below:

[0142] Table: Performance test results in Application Example 1 and Comparative Examples 1-3

[0143]

[0144] As can be seen from the table above, the epoxy grout used in Example 1 exhibits excellent toughness and resistance to heat-induced yellowing in its cured product, with a tensile strength as high as 66 MPa, an elongation at break as high as 12.6%, and an impact toughness of 110 KJ / m. 2 Furthermore, it does not yellow after UV irradiation, and retains up to 99% of its strength and toughness.

[0145] Compared to comparisons 1-3, all showed varying degrees of improvement. The reasons for this may be as follows:

[0146] The flexible, yellowing-resistant epoxy resin composition in this application significantly enhances the toughness of the carbocyclic epoxy resin by introducing specific R groups, such as isocyanate compounds with two -NCO groups and linear polyhydroxy compounds with two -OH groups.

[0147] Specifically, this can be achieved by promoting the grafting reaction between NCO and the side hydroxyl groups in the resin matrix, and generating a polyether-type polyhydroxy compound isocyanate grafted with 2 molecules of epoxy, i.e., general formula (II), thereby achieving the purpose of toughening. Obviously, the comparison documents 1-3 cannot do this.

[0148] Furthermore, since the hydroxyl groups of the epoxy resin in this application are blocked by the grafting reaction of the polyether-type polyhydroxy compound isocyanate, the longitudinal molecular motion energy of the epoxy groups in the molecular chain segment is reduced, thereby enhancing its heat resistance and yellowing resistance while maintaining heat resistance.

[0149] In summary, the toughening method introduced by the specific resin and its specific R group in this application will not affect the original UV yellowing resistance of the resin matrix. It still has good refractive properties, and after UV aging, the strength retention rate can reach 99%. It is not easy to powder and fall off during application.

[0150] Application Example 2-6

[0151] An epoxy grout sealant differs from Application Example 1 in that the flexible, yellowing-resistant epoxy resin composition used is different, as shown in the table below.

[0152] Table: Comparison of the Usage of Flexible Yellowing-Resistant Epoxy Resin Compositions in Examples 2-6

[0153] Group Flexible, yellowing-resistant epoxy resin composition Example 2 Prepared from Preparation Example 2 Example 3 Prepared from Preparation Example 3 Example 4 Prepared from Preparation Example 4 Example 5 Prepared from Preparation Example 5 Example 6 Prepared from Preparation Example 6

[0154] The epoxy grout prepared in Application Examples 2-6 were sampled, and their tensile strength, elongation at break, impact strength, heat resistance to yellowing, strength retention rate after UV irradiation, and toughness retention rate after UV irradiation were tested. The average values ​​of the test results were recorded in the table below: Table: Performance Test Results in Application Examples 2-6

[0155]

[0156]

[0157] As can be seen from the table above, the epoxy grout used in Examples 1-6 exhibits a tensile strength of 55-66 MPa, an elongation at break of 5.6-13.8%, and an impact toughness of 65-110 KJ / m². 2 Furthermore, it does not yellow after UV irradiation, and its strength and toughness retention rate is as high as 92-99%.

[0158] It can be seen that, under the premise of a certain amount of isocyanate compound, the above-selected isocyanate compounds can effectively promote the grafting reaction between their NCO and the side hydroxyl groups in the resin matrix, and generate a polyether-type polyhydroxy compound isocyanate grafted with 2 molecules of epoxy, i.e., general formula (II), thereby achieving toughening.

[0159] Furthermore, as can be seen from Application Examples 1-4 and 5-6, the single isocyanate compounds are preferably isophorone diisocyanate and methylcyclohexyl diisocyanate, followed by hexamethylene diisocyanate and trimethylhexamethylene diisocyanate. The combined group is less effective than the single-use group.

[0160] The reason for this may be that when symmetrical and asymmetrical NCOs are simultaneously introduced into the reaction system, steric hindrance between them can have adverse effects, leading to a disordered molecular structure and uncontrollable molecular weight distribution. Since both symmetrical and asymmetrical NCOs participate in cross-linking, the symmetrical NCO structure has weak reaction selectivity and may act as a chain extender, resulting in an increase in high-molecular-weight byproducts and a sharp rise in viscosity. Simultaneously, due to the excessively high viscosity of the system, the molecular motion of some low-molecular-weight substances is hindered, preventing a small number of residues from participating in the reaction and causing a significant decrease in product performance.

[0161] Application Example 7-11

[0162] An epoxy grout sealant differs from Application Example 1 in that the flexible, yellowing-resistant epoxy resin composition used is different, as shown in the table below.

[0163] Table: Comparison of the Usage of Flexible Yellowing-Resistant Epoxy Resin Compositions in Examples 7-11

[0164] Group Flexible, yellowing-resistant epoxy resin composition Example 7 Prepared from Preparation Example 7 Example 8 Prepared from Preparation Example 8 Example 9 Prepared from Preparation Example 9 Example 10 Prepared from Preparation Example 10 Example 11 Prepared from Preparation Example 11

[0165] The epoxy grout prepared in Application Examples 7-11 above was sampled, and its tensile strength, elongation at break, impact strength, heat resistance to yellowing, strength retention rate after UV irradiation, and toughness retention rate after UV irradiation were tested. The average values ​​of the test results are recorded in the table below:

[0166] Table: Performance Test Results in Application Example 7-11

[0167]

[0168] As can be seen from the table above, the epoxy grout used in Examples 1 and 7-11 exhibits a tensile strength of 56-73 MPa, an elongation at break of 7.3-14.2%, and an impact toughness of 72-110 KJ / m². 2 Furthermore, it does not yellow after UV irradiation, and retains 98-99% of its strength and toughness.

[0169] It can be seen that, under the premise of a certain amount of polyether-type polyhydroxy compound, the above-mentioned polyether-type polyhydroxy compound isocyanate is beneficial to the grafting reaction and blocking of hydroxyl groups on epoxy resin, thereby achieving the maintenance of heat resistance by reducing the longitudinal molecular mobility of epoxy groups in the molecular chain segment, with application examples 1, 7, and 9-10 being preferred examples.

[0170] Application Example 12-16

[0171] An epoxy grout sealant differs from application example 5 in that the flexible, yellowing-resistant epoxy resin composition used is different, as shown in the table below.

[0172] Table: Comparison of the Usage of Flexible Yellowing-Resistant Epoxy Resin Compositions in Examples 12-16

[0173] Group Flexible, yellowing-resistant epoxy resin composition Example 12 Prepared from Preparation Example 12 Example 13 Prepared from Preparation Example 13 Example 14 Prepared from Preparation Example 14 Example 15 Prepared from Preparation Example 15 Example 16 Prepared from Preparation Example 16

[0174] The epoxy grout prepared in Application Examples 12-16 above were sampled, and their tensile strength, elongation at break, impact strength, heat resistance to yellowing, strength retention rate after UV irradiation, and toughness retention rate after UV irradiation were tested. The average values ​​of the test results are recorded in the table below:

[0175] Table: Performance Test Results in Application Examples 12-16

[0176]

[0177] As can be seen from the table above, the epoxy grout used in Examples 12-16 exhibits a tensile strength of 64-74 MPa, an elongation at break of 15.9-21.3%, and an impact toughness of 102-124 KJ / m². 2 Furthermore, it does not yellow after UV irradiation, and retains up to 99% of its strength and toughness.

[0178] Compared to application example 5, all showed varying degrees of improvement. The reasons for this may be as follows:

[0179] With a fixed isocyanate composition, the steric hindrance of the grafting reaction with the side hydroxyl groups can be significantly reduced by the stepwise addition of symmetrical NCO-hexamethylene diisocyanate and asymmetrical NCO-isophorone diisocyanate, thereby enhancing the degree of reaction and achieving further toughening.

[0180] Furthermore, as can be seen from Application Examples 12-16, symmetrical NCO-hexamethylene diisocyanate and asymmetrical NCO-isophorone diisocyanate, under the premise of a certain total amount, also have preferred ratios and ranges. Application Examples 13-15 are the optimal ratio ranges, which can take into account their various properties.

[0181] Application Example 17-19

[0182] An epoxy grout sealant differs from application example 14 in that the flexible, yellowing-resistant epoxy resin composition used is different, as shown in the table below.

[0183] Table: Comparison of the Usage of Flexible Yellowing-Resistant Epoxy Resin Compositions in Examples 17-19

[0184]

[0185]

[0186] The epoxy grout prepared in Application Examples 17-19 above were sampled, and their tensile strength, elongation at break, impact strength, heat resistance to yellowing, strength retention rate after UV irradiation, and toughness retention rate after UV irradiation were tested. The average values ​​of the test results are recorded in the table below:

[0187] Table: Performance Test Results in Application Examples 17-19

[0188]

[0189] As can be seen from the table above, the epoxy grout used in Examples 17-19 has a tensile strength of 71-62 MPa, an elongation at break of 8.8-21.0%, and an impact toughness of 57-121 KJ / m². 2 Furthermore, some parts exhibit yellowing after UV irradiation, with a retention rate of 78-99% for strength and toughness.

[0190] Compared to Application Example 14, all showed varying degrees of decrease. The possible reasons are as follows: 1) the total reaction time of the fractional addition was extended; 2) the order of addition of the two different isocyanate compounds was changed; and 3) the optimal reaction temperature during addition was changed. In summary, these factors affected the progress of the reaction.

[0191] Application Examples 20-25

[0192] An epoxy grout sealant differs from Application Example 1 in that the flexible, yellowing-resistant epoxy resin composition used is different, as shown in the table below.

[0193] Table: Comparison of the Usage of Flexible Yellowing-Resistant Epoxy Resin Compositions in Examples 20-25

[0194]

[0195]

[0196] The epoxy grout prepared in Application Examples 20-25 above were sampled, and their tensile strength, elongation at break, impact strength, heat resistance to yellowing, strength retention rate after UV irradiation, and toughness retention rate after UV irradiation were tested. The average values ​​of the test results are recorded in the table below:

[0197] Table: Performance Test Results in Application Examples 20-25

[0198]

[0199] As can be seen from the table above, the epoxy grout used in Examples 20-24 exhibits a tensile strength of 56-72 MPa, an elongation at break of 9.8-19.6%, and an impact toughness of 87-118 KJ / m². 2 Furthermore, it does not yellow after UV irradiation, and its strength and toughness retention rate is as high as 94-98%.

[0200] It can be seen that the material ratio of each component in S3 will also affect the performance of the final resin composition. The optimal mass ratio of the carbocyclic compound, polyether-type polyhydroxy compound modified isocyanate intermediate and catalyst represented by general formula (I) after dehydration and drying in S3 is 100:(10-60):(0.001-3).

[0201] As can be seen from Application Examples 1 and 25, it is not necessarily the case that more feeding times or a slower overall feeding progress is more conducive to the reaction. Simply increasing the number of feeding times or reducing the amount used each time will affect the overall reaction and thus its final performance.

[0202] This specific preparation example is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this preparation example without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A flexible, yellowing-resistant epoxy resin composition, characterized by comprising: comprising one or more carbon ring compounds represented by general formula (I) and one or more carbon ring compounds represented by general formula (II); Formula (I); Formula (II); in general formula (I) and (II): n is not 0; R1and R2are each independently selected from the group consisting of -H, C1-C6alkyl; 20 alkyl; R3 is independently selected from the residue of isocyanate compounds having two -NCO groups in the molecule; R4 is selected from the residue of polyether type polyol compounds containing -OH; The carbon ring compound represented by general formula (II) is formed by grafting an intermediate generated by reacting a polyether type polyol compound containing -OH with isocyanate compounds having two -NCO groups in the molecule with the compound of general formula (I).

2. The flexible, yellowing-resistant epoxy resin composition according to claim 1, characterized in that, The isocyanate compounds having two -NCO groups in the molecule are selected from one or more of 1,4-cyclohexyl diisocyanate, isophorone diisocyanate, methylcyclohexyl diisocyanate, 4,4'-dicyclohexyl methane diisocyanate, hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, m-xylylene diisocyanate.

3. The flexible, yellowing-resistant epoxy resin composition of claim 1, wherein The polyether type polyol compound containing -OH is selected from one of polyethylene oxide, polypropylene oxide, polyoxetane, polytetrahydrofuran, propylene oxide and ethylene oxide copolymer.

4. A process for the production of the flexible, yellowing-resistant epoxy resin composition according to any one of claims 1 to 3, characterized in that comprising the following steps: S1, weigh the carbon ring compound represented by general formula (I), heat to 110-125℃, vacuum to remove water, and then naturally cool to room temperature under nitrogen protection conditions, and reserve; S2, weigh the polyether type polyol compound containing -OH, heat to 110-120℃, vacuum to remove water, and then naturally cool to 50-60℃ under nitrogen protection conditions; First add the catalyst, then add the isocyanate compounds having two -NCO groups in stages, and react at a reaction temperature of 40-70℃ for 1.5-4.0h until the NCO content is stable, to obtain the polyether type polyol compound modified isocyanate intermediate; The step of adding the isocyanate compounds having two -NCO groups in stages includes adding the symmetric isocyanate in the first stage and adding the asymmetric isocyanate in the second stage; S3, add the carbon ring compound represented by general formula (I) treated in S1 to the polyether type polyol compound modified isocyanate intermediate obtained in S2 under nitrogen protection conditions in three batches, with an interval of 20℃ between each batch, after the addition is complete, add the catalyst, heat to 80-120℃ and continue to react for 1-6h until the titration NCO content is 0, then continue to react for 1-2h, and discharge, to obtain the flexible yellowing-resistant epoxy resin composition.

5. The method of claim 4, wherein the flexible, yellowing-resistant epoxy resin composition is prepared by mixing the epoxy resin, the curing agent, the curing catalyst, the antioxidant, the ultraviolet absorber, the light stabilizer, the thermal stabilizer, the flame retardant, the filler, and the solvent. 5 The mass ratio of the polyether type polyol compound, the catalyst and the isocyanate compounds having two -NCO groups in S2 is 100:(0.001-3):(1-45).

6. The method for preparing the flexible, yellowing-resistant epoxy resin composition according to any one of claims 4 or 5, characterized in that, The method of adding the isocyanate compounds having two -NCO groups in stages in S2 is as follows: First stage addition: maintain the internal temperature at 50±10℃, add 5-15 parts by mass of the symmetric isocyanate, and stir for 10-30min, then heat to 60±10℃; Secondary dropwise addition: continue to dropwise add 10-30 parts by mass of asymmetric isocyanate, and after the dropwise addition is completed, continue to keep warm for 1-3 h until the NCO content is stable, thereby obtaining the polyether polyol modified isocyanate intermediate.

7. The method for preparing the flexible, yellowing-resistant epoxy resin composition according to claim 4, characterized in that, The mass ratio of the carbon ring compound represented by general formula (I), the polyether polyol modified isocyanate intermediate, and the catalyst after the dehydration and drying treatment in S3 is 100:(10-60):(0.001-3).

8. The method for preparing the flexible, yellowing-resistant epoxy resin composition according to any one of claims 4 or 7, characterized in that, The method of batch addition in S3 is as follows: First batch of feeding: first feed the first batch at 50±10°C, and after stirring for 30 min; Second batch of feeding: after the temperature is raised to 70±10°C, feed the second batch, and continue to stir for 30 min; Third batch of feeding: after the temperature is raised to 90±10, feed the third batch, and the feeding is completed; Then continue to react at 80-120°C for 1-6 h until the titration NCO content is 0, continue to keep warm for 1-3 h, discharge, and thereby obtain the flexible yellowing-resistant epoxy resin composition.

9. Use of the flexible, yellowing-resistant epoxy resin composition according to any one of claims 1 to 4 in adhesives, sealants, potting, chip packaging, LED packaging, paints, epoxy joint sealants, overprint varnishes, characterized in that The amount is 10-100%.

10. The use of the flexible, yellowing-resistant epoxy resin composition according to claim 9, characterized in that, The epoxy sealant also includes 5-100% of a curing agent; The curing agent is one or more of aliphatic amine, alicyclic amine, modified amine, and polyether amine.

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