A MINI LED display screen packaging material and preparation method thereof

Abstract

The present invention relates to MINI LED display screen packaging material and its preparation process, and belongs to the technical field of display screen packaging. The packaging material includes the following raw materials in parts by weight: 60-80 parts of epoxy resin, 20-40 parts of toughening agent, 80-130 parts of curing agent, and 5-20 parts of auxiliary agent; the toughening agent is a double-ended isocyanate silicone oil and a functional diol in acetone, and is obtained by reaction under the action of an organic tin catalyst; the double-ended isocyanate silicone oil is a dihydroxy silicone oil and a diisocyanate in acetone, and is obtained by reaction under the action of an organic tin catalyst; the functional diol is obtained by the esterification reaction product of dimethylol propionic acid and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical and dibenzoyl peroxide. The present invention improves the heat resistance of epoxy resin and reduces its thermal expansion coefficient by adding a toughening agent.

Description

Technical Field

[0001] The present invention belongs to the technical field of display screen packaging, and in particular, relates to a MINI LED display screen packaging material and a preparation process thereof. Background Art

[0002] MINI LED refers to LED chips with a size of 100-300 microns, which is between small-pitch LED and MicroLED. It has a large number of lamp beads, high brightness, multiple partitions, and is easy to achieve 8K without screen burn-in. It has good display effects and is eye-protecting and colorful. It is one of the hot spots in the development of display technology. When packaging the MINI LED display, many lamp beads need to be welded and packaged, and the existing packaging materials include epoxy resin, silicone and other highly transparent materials. The above-mentioned packaging materials have a high thermal expansion coefficient. During packaging, the packaging materials often expand rapidly, the solder joints do not expand, the solder joints break, and the lamp beads fail, resulting in reduced product yield or even damage. Therefore, maintaining the consistency of the thermal expansion coefficients of the packaging materials and the solder joints is the key to the packaging process of the MINI LED display.

[0003] Based on this, the present invention provides a MINI LED display screen packaging material and a preparation process thereof. Summary of the invention

[0004] The object of the present invention is to provide a MINI LED display screen packaging material and a preparation method thereof, so as to solve the problem that the thermal expansion coefficient of the existing packaging material is inconsistent with the thermal expansion coefficient of the solder joint.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] The first object of the present invention is to provide a MINI LED display screen packaging material, comprising the following raw materials in parts by weight: 60-80 parts of epoxy resin, 20-40 parts of toughening agent, 80-130 parts of curing agent, and 5-20 parts of auxiliary agent;

[0007] The toughening agent is obtained by reacting double-ended isocyanate silicone oil and functional diol in acetone under the action of an organic tin catalyst;

[0008] The double-terminal isocyanate silicone oil is obtained by reacting dihydroxy silicone oil and diisocyanate in acetone under the action of an organic tin catalyst;

[0009] The functional diol is obtained by reacting an esterification product of dimethylol propionic acid and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical with dibenzoyl peroxide.

[0010] Furthermore, the epoxy resin is at least one of a linear epoxy resin and a phenolic epoxy resin.

[0011] Furthermore, in the toughening agent obtaining reaction, the mass ratio of the double-terminal isocyanate silicone oil to the functional diol is 10-15:1.

[0012] Furthermore, in the toughening agent obtaining reaction, the reaction temperature is 55-60° C. and the reaction time is 6-12 h.

[0013] Furthermore, in the reaction for obtaining the double-terminal isocyanate-based silicone oil, the mass ratio of the dihydroxy-terminated polydimethylsiloxane to diisocyanate is 10:3-6.

[0014] Furthermore, the diisocyanate is one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate, preferably isophorone diisocyanate.

[0015] Furthermore, in the reaction for obtaining the double-ended isocyanate silicone oil, the reaction temperature is 50-60° C. and the reaction time is 3-5 h.

[0016] Furthermore, the organic tin catalyst is dibutyltin dilaurate.

[0017] Furthermore, an organic solvent, an esterification reaction catalyst and a water absorbent triethylamine are added during the esterification reaction to further improve the yield of ester in the esterification reaction.

[0018] Furthermore, the organic solvent is one of toluene, benzene, carbon tetrachloride and carbon dichloride.

[0019] Furthermore, the esterification reaction catalyst is one of concentrated sulfuric acid and p-toluenesulfonic acid.

[0020] Furthermore, during the esterification reaction, the reaction temperature is 85-95° C. and the reaction time is 4-24 h.

[0021] Preferably, the esterification reaction is carried out as follows:

[0022] Dimethylolpropionic acid, 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl free radical and benzene are uniformly mixed in a molar ratio of 1:1, triethylamine is added, and the mixture is heated to the esterification reaction temperature. Then, sulfuric acid is slowly added dropwise under stirring, and the mixture is kept warm for 4-24 hours. The reaction is stopped, the mixture is allowed to stand for stratification, the organic phase is collected, and water is removed from the organic phase to obtain an esterification reaction product. The amount of triethylamine added is the equivalent of the dimethylolpropionic acid.

[0023] Furthermore, the esterification reaction product and dibenzoyl peroxide are reacted in tetrahydrofuran at room temperature for 4-24 hours.

[0024] Preferably, the reaction of the esterification product and dibenzoyl peroxide is carried out as follows:

[0025] After the esterification reaction product and tetrahydrofuran are uniformly mixed, a tetrahydrofuran solution of dibenzoyl peroxide is slowly added dropwise, and the reaction is stirred at room temperature for 4-24 hours. The reaction is stopped, and the reaction is separated by chromatography to obtain a functional diol.

[0026] Preferably, the added amount of the dibenzoyl peroxide is an equivalent of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical, that is, the molar ratio of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical to dibenzoyl peroxide is 1:1.

[0027] In the above reaction, the coupling reaction of the free radicals in the esterification reaction product and dibenzoyl peroxide is utilized to obtain a functional diol containing a nitrogen oxide bond containing a hindered amine. When the functional diol reacts with a double-ended isocyanate silicone oil, a hydroxyl group and an isocyanate bond are reacted to obtain a toughening agent. It can be seen that the nitrogen oxide bond containing the hindered amine exists in the toughening agent molecule in the form of a side chain. The nitrogen oxide bond of the hindered amine on the side chain is easily used to generate nitrogen oxide free radicals, which can capture the active free radicals generated by the epoxy resin when heated (during packaging and welding), thereby improving the weathering stability of the epoxy resin and reducing the expansion coefficient of the epoxy resin.

[0028] Furthermore, the curing agent is any one of phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride and methylphthalic anhydride.

[0029] Furthermore, the auxiliary agent is an antioxidant and a diluent; the antioxidant is a well-known additive in the technical field, and the present invention does not specifically limit its type and addition amount; the diluent is a well-known additive in the technical field, and the present invention does not specifically limit its type and addition amount.

[0030] The second object of the present invention is to provide a preparation process of a MINI LED display screen packaging material, comprising:

[0031] The epoxy resin, toughening agent, curing agent and auxiliary agent are mixed evenly, stirred at 60-120° C. for 20-30 minutes, discharged, cooled, and the packaging material is obtained.

[0032] Beneficial effects of the present invention:

[0033] The present invention provides a MINI LED display screen packaging material and a preparation process thereof, which improves the heat resistance of epoxy resin and reduces its thermal expansion coefficient by adding a toughening agent, thereby solving the problems mentioned in the background technology;

[0034] Significantly, the molecules of the toughening agent added in the present invention contain silicone molecular chains, polyurethane chains and side chains containing nitrogen-oxygen bonds of hindered amines. The elasticity and heat resistance of the epoxy resin are improved through the heat resistance and elasticity of the silicone molecular chains and polyurethane chains, and the heat resistance of the epoxy resin is further improved through the side chains containing nitrogen-oxygen bonds of hindered amines, and its thermal expansion coefficient is reduced. DETAILED DESCRIPTION

[0035] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] Preparation of double-terminal isocyanate silicone oil:

[0038] After mixing 20g of isophorone diisocyanate and 0.6g of dibutyltin dilaurate, 100mL of acetone solution containing 6g (after vacuum dehydration) of dihydroxy-terminated polydimethylsiloxane was added dropwise, the reaction temperature was controlled at 50°C, and after the addition was complete, the mixture was stirred for 5h, the reaction was stopped, and vacuum rotary evaporation was performed to obtain diisocyanate-based silicone oil. The average relative molecular mass of the dihydroxy-terminated polydimethylsiloxane was 2000-2500.

[0039] Example 2

[0040] Preparation of double-terminal isocyanate silicone oil:

[0041] After mixing 20g of isophorone diisocyanate and 0.6g of dibutyltin dilaurate, 100mL of acetone solution containing 8g (after vacuum dehydration) of dihydroxy-terminated polydimethylsiloxane was added dropwise, the reaction temperature was controlled at 60°C, and after the addition was complete, the mixture was stirred for 3h, the reaction was stopped, and vacuum rotary evaporation was performed to obtain diisocyanate-based silicone oil. The average relative molecular mass of the dihydroxy-terminated polydimethylsiloxane was 2000-2500.

[0042] Example 3

[0043] Preparation of functional diols:

[0044] The first step is to mix 0.1 mol dihydroxymethylpropionic acid, 0.1 mol 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl free radical and 80 mL benzene evenly, add 0.1 mol triethylamine, heat to 85°C, then slowly add sulfuric acid dropwise under stirring, and keep the temperature for 12 hours, stop the reaction, let the layers stand, collect the organic phase, remove water from the organic phase, and obtain the esterification reaction product;

[0045] Step 2: Evenly mix the esterification product produced in the first step with 90 mL of tetrahydrofuran, slowly drop 60 mL of a tetrahydrofuran solution containing 0.1 mol of dibenzoyl peroxide, stir the mixture at room temperature for 4 h, stop the reaction, separate by chromatography, and obtain a functional diol.

[0046] Example 4

[0047] Preparation of functional diols:

[0048] The first step is to mix 0.1 mol dihydroxymethylpropionic acid, 0.1 mol 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl free radical and 80 mL benzene evenly, add 0.1 mol triethylamine, heat to 95°C, then slowly add sulfuric acid dropwise under stirring, and keep the temperature for 4 hours, stop the reaction, let the layers stand, collect the organic phase, remove water from the organic phase, and obtain the esterification reaction product;

[0049] Step 2: Evenly mix the esterification product produced in the first step with 90 mL of tetrahydrofuran, slowly drop 60 mL of a tetrahydrofuran solution containing 0.1 mol of dibenzoyl peroxide, stir the mixture at room temperature for 14 h, stop the reaction, separate by chromatography, and obtain a functional diol.

[0050] Example 5

[0051] Preparation of toughening agent:

[0052] 100 g of the double-ended isocyanate silicone oil prepared in Example 1, 10 g of the functional diol prepared in Example 3 and 200 mL of acetone were mixed evenly, 20 mL of acetone containing 1.5 g of dibutyltin dilaurate was added dropwise, heated to 55° C., and stirred for reaction for 12 h to obtain a toughening agent.

[0053] Example 6

[0054] Preparation of toughening agent:

[0055] 150 g of the double-ended isocyanate silicone oil prepared in Example 1, 10 g of the functional diol prepared in Example 3 and 200 mL of acetone were evenly mixed, 20 mL of acetone containing 2 g of dibutyltin dilaurate was added dropwise, heated to 60° C., and stirred for reaction for 6 hours to obtain a toughening agent.

[0056] Comparative Example 1

[0057] This comparative example provides a toughening agent:

[0058] The toughening agent is the double-terminal isocyanate silicone oil prepared in Example 1.

[0059] Example 7

[0060] Preparation of packaging materials:

[0061] Step A, take the following raw materials in parts by weight: 60 parts of epoxy resin, 40 parts of toughening agent, 80 parts of curing agent, and 11 parts of auxiliary agent;

[0062] The epoxy resin is bisphenol S linear epoxy resin, the curing agent is tetrahydrophthalic anhydride, the auxiliary agent is an antioxidant and a diluent, the antioxidant is antioxidant 1010, the addition amount is 5 parts, the diluent is allyl glycidyl ether, the addition amount is 6 parts;

[0063] Step B: Evenly mix the epoxy resin, toughening agent, curing agent and auxiliary agent, stir at 60° C. for 30 minutes, discharge the mixture, and cool the mixture to obtain a packaging material.

[0064] Example 8

[0065] Preparation of packaging materials:

[0066] Step A, take the following raw materials by weight: 70 parts of epoxy resin, 30 parts of toughening agent, 100 parts of curing agent, and 15 parts of auxiliary agent;

[0067] The epoxy resin is bisphenol S linear epoxy resin, the curing agent is tetrahydrophthalic anhydride, the auxiliary agent is an antioxidant and a diluent, the antioxidant is antioxidant 1010, the addition amount is 3 parts, the diluent is allyl glycidyl ether, the addition amount is 10 parts;

[0068] Step B: Evenly mix the epoxy resin, toughening agent, curing agent and auxiliary agent, stir at 100° C. for 25 minutes, discharge the mixture, and cool the mixture to obtain a packaging material.

[0069] Example 9

[0070] Preparation of packaging materials:

[0071] Step A, take the following raw materials in parts by weight: 80 parts of epoxy resin, 20 parts of toughening agent, 130 parts of curing agent, and 11 parts of auxiliary agent;

[0072] The epoxy resin is bisphenol S linear epoxy resin, the curing agent is tetrahydrophthalic anhydride, the auxiliary agent is an antioxidant and a diluent, the antioxidant is antioxidant 1010, the addition amount is 3 parts, the diluent is allyl glycidyl ether, the addition amount is 8 parts;

[0073] Step B: Evenly mix the epoxy resin, toughening agent, curing agent and auxiliary agent, stir at 120° C. for 20 minutes, discharge the mixture, and cool the mixture to obtain a packaging material.

[0074] Comparative Example 2

[0075] Preparation of packaging material: Compared with Example 7, an equal amount of the toughening agent is replaced with the toughening agent prepared in Comparative Example 1, and the rest is the same.

[0076] Comparative Example 3

[0077] Preparation of packaging material: Compared with Example 7, the toughening agent was deleted and the rest was the same.

[0078] The packaging materials obtained in Examples 7-9 and Comparative Examples 2-3 were sampled according to the test standard requirements and then tested, wherein the tensile property test was conducted using ISO 37, the Vicat temperature was conducted using GB / T1633-2000, the thermal expansion coefficient was conducted using ASTM D-696, and the water absorption rate was measured using a 2h boiling water immersion method;

[0079] unit Example 7 Example 8 Example 9 Comparative Example 2 Comparative Example 3 Tensile Strength MPa 87 85 80 77 69 Elongation at break ％ 9 8 8 7 4 Vicat temperature ℃ 198 190 181 162 136 Coefficient of thermal expansion ppm / K 1.22 1.31 1.40 1.81 5.21 Water absorption ％ 0.21 0.30 0.39 0.40 1.8

[0080] It can be seen from the data in Table 1 that the elastic properties and heat resistance temperature of the packaging materials obtained in Examples 7-9 are better than those of the packaging materials obtained in Comparative Examples 2-3.

[0081] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0082] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A MINI LED display screen packaging material, characterized in that: The method comprises the following raw materials in parts by weight: 60-80 parts of epoxy resin, 20-40 parts of toughening agent, 80-130 parts of curing agent, and 5-20 parts of auxiliary agent; The toughening agent is obtained by reacting double-ended isocyanate silicone oil and functional diol in acetone under the action of an organic tin catalyst; The double-terminal isocyanate silicone oil is obtained by reacting dihydroxy-terminated polydimethylsiloxane and diisocyanate in acetone under the action of an organic tin catalyst; The functional diol is obtained by reacting the esterification product of dimethylol propionic acid and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical with dibenzoyl peroxide; In the toughening agent obtaining reaction, the mass ratio of the double-terminal isocyanate silicone oil to the functional diol is 10-15:

1.

2. A MINI LED display screen packaging material according to claim 1, characterized in that: In the toughening agent obtaining reaction, the reaction temperature is 55-60° C. and the reaction time is 6-12 hours.

3. The MINI LED display screen packaging material according to claim 1, characterized in that: In the reaction for obtaining the double-terminal isocyanate silicone oil, the mass ratio of the double-hydroxy-terminated polydimethylsiloxane to diisocyanate is 10:3-6.

4. The MINI LED display screen packaging material according to claim 1, characterized in that: In the reaction of obtaining the double-ended isocyanate silicone oil, the reaction temperature is 50-60° C. and the reaction time is 3-5 hours.

5. The MINI LED display screen packaging material according to claim 1, characterized in that: During the esterification reaction, an organic solvent, an esterification reaction catalyst and a water absorbent triethylamine are added.

6. The MINI LED display screen packaging material according to claim 1, characterized in that: During the esterification reaction, the reaction temperature is 85-95° C. and the reaction time is 4-24 h.

7. The MINI LED display screen packaging material according to claim 1, characterized in that: The reaction of the esterification reaction product and dibenzoyl peroxide is carried out in tetrahydrofuran.

8. The MINI LED display screen packaging material according to claim 1, characterized in that: In the reaction between the esterification reaction product and dibenzoyl peroxide, the reaction temperature is room temperature and the reaction time is 4-24 hours.

9. A process for preparing a MINI LED display screen packaging material according to any one of claims 1 to 8, characterized in that: include: The epoxy resin, toughening agent, curing agent and auxiliary agent are mixed evenly, stirred at 60-120° C. for 20-30 minutes, discharged, cooled, and the packaging material is obtained.