Hot melt adhesive for bonding LED backlight TV light strips and preparation method thereof

Abstract

The present application relates to the technical field of hot melt adhesives, and in particular to a hot melt adhesive for bonding LED backlight TV light strips and a preparation method thereof. A hot melt adhesive for bonding LED backlight TV light strips comprises the following components in parts by weight: 40-65 parts of modified polyester resin, 1-8 parts of graphene, 1-8 parts of hexagonal boron nitride nanosheets, 9-15 parts of rosin resin, 0.5-1.5 parts of plasticizer and 0.1-1 parts of antioxidant, wherein the modified polyester resin is a polyester resin modified by galactomannan. The preparation method of the hot melt adhesive for bonding LED backlight TV light strips comprises the following steps: adding modified polyester resin, graphene, hexagonal boron nitride nanosheets, rosin resin, plasticizer, and antioxidant to a mixer, mixing under nitrogen protection, extruding and granulating, and preparing the hot melt adhesive for bonding LED backlight TV light strips. The hot melt adhesive prepared in the present application has good bonding performance and is not easy to become brittle or crack at low temperatures.

Description

Technical Field

[0001] The present application relates to the technical field of hot melt adhesives, and in particular to a hot melt adhesive for bonding LED backlight TV light strips and a preparation method thereof. Background Art

[0002] In the LED backlight TV manufacturing industry, precise positioning and stable bonding of light strips are key links to ensure uniform picture quality and product durability. Traditionally, materials used for bonding LED backlight TV light strips need to have high bonding strength, good wettability, strong environmental adaptability, and meet green environmental protection requirements. Polyester hot melt adhesive is a saturated linear thermoplastic resin synthesized by esterification, transesterification and polycondensation of finely regulated polyacids and polyols. It has shown great application potential in the field of electronic manufacturing due to its fast curing, high bonding efficiency, wide material compatibility, and environmentally friendly and non-toxic properties.

[0003] Although polyester hot melt adhesive has excellent basic performance, its wetting performance is limited when bonding polar materials (metal substrates), which may lead to tiny bubbles or gaps in the bonding interface, thus affecting the integrity and strength of the bond. Secondly, during the long-term use of LED backlight TVs, especially in environments with large temperature fluctuations, the durability of the bonding force of polyester hot melt adhesive becomes one of the considerations. If its bonding force gradually weakens over time, it will increase the risk of the light bar falling off or shifting, directly affecting the display effect and service life of the TV. Furthermore, considering that the working environment of LED backlight TVs may involve low temperature conditions, the toughness of polyester hot melt adhesive at low temperatures also needs attention. Materials tend to become brittle at low temperatures, which not only affects the operating performance during bonding, but may also accelerate the cracking of the bonding interface, posing a threat to the reliability and safety of the product. Summary of the invention

[0004] The purpose of the present invention is to provide a hot melt adhesive for bonding LED backlight TV light strips and a preparation method thereof, so as to solve the technical problems existing in the prior art that polyester hot melt adhesive cannot take into account the adhesion and durability to polar materials, and that polyester hot melt adhesive becomes brittle and easy to crack at low temperatures.

[0005] In the first aspect, the present application provides a hot melt adhesive for bonding LED backlight TV light strips, comprising the following components in parts by weight: 40-65 parts of modified polyester resin, 1-8 parts of graphene, 1-8 parts of hexagonal boron nitride nanosheets, 9-15 parts of rosin resin, 0.5-1.5 parts of plasticizer and 0.1-1 part of antioxidant, wherein the modified polyester resin is obtained by modifying polyester resin with galactomannan.

[0006] By adopting the above technical scheme, the present application selects modified polyester resin as the base material, which provides bonding performance. The modified polyester resin has good low-temperature stability, heat resistance and good chemical stability; graphene has extremely high thermal conductivity, which can significantly improve the thermal conductivity of hot melt adhesive, help LED light strips to better dissipate heat and extend service life; hexagonal boron nitride nanosheets are also a high-performance thermal conductive filler, which not only has good insulation performance, but also has good thermal conductivity, which can enhance the thermal conductivity of hot melt adhesive; rosin resin, as a kind of adhesive, can improve the bonding performance of hot melt adhesive, increase initial adhesion, and help improve the wettability and adhesion of hot melt adhesive; plasticizer can reduce the glass transition temperature of hot melt adhesive, making it easier to flow at lower temperatures, while increasing its flexibility and ductility and reducing brittleness; antioxidant can prevent hot melt adhesive from oxidative degradation during heating and extend its service life.

[0007] Optionally, the hot melt adhesive for bonding LED backlight TV light strips comprises the following components in parts by weight: 50-58 parts of modified polyester resin, 3-5 parts of graphene, 2-5 parts of hexagonal boron nitride nanosheets, 10-12 parts of rosin resin, 0.9-12 parts of plasticizer and 0.5-0.8 parts of antioxidant.

[0008] Optionally, the modified polyester resin comprises the following raw materials: polyester resin, galactomannan, epoxidized soybean oil, talc and 3-pentanone.

[0009] Optionally, the weight ratio of the polyester resin, galactomannan, epoxidized soybean oil, talc and 3-pentanone is 100:(20-30):(7-12):(2-4):1.

[0010] Optionally, the method for preparing the modified polyester resin comprises the following steps: S1, melt the polyester resin first, and then cool it to 75-78°C; S2, add galactomannan to the material of S1, heat up and stir rapidly, when wire drawing occurs, add epoxidized soybean oil and talcum powder, stir evenly and heat in an oil bath; S3, after cooling to room temperature, adding 3-pentanone to the material in S2 and mixing and stirring to obtain the modified polyester resin.

[0011] Optionally, in S2, the temperature of the oil bath heating is 185-190°C and the time is 2-3h.

[0012] First, since galactomannan is a polysaccharide compound, its molecular chain contains a large number of hydroxyl groups (-OH) and other polar groups. These groups can interact with the molecular chains in the polyester resin, such as hydrogen bonding, thereby introducing more flexible segments or cross-linking points in the molecular network of the polyester resin. This intermolecular interaction helps to improve the molecular chain arrangement and conformation of the hot melt adhesive and increase the flexibility of its molecular chain; secondly, galactomannan and polyester resin may have good interfacial compatibility, which helps to reduce the interfacial tension between the two, so that galactomannan can be evenly dispersed in the matrix of the polyester resin. The uniform dispersion can more effectively play the modifying role of galactomannan and improve the low-temperature flexibility of the hot melt adhesive; finally, during the modification process, the addition of a small amount of epoxy soybean oil and a trace amount of talc further enhances the interaction between the polyester resin and galactomannan. These additives act as a bridge or medium to promote the combination between the two and form a more compact and stable molecular network structure. This structure can better resist the action of external forces at low temperatures and reduce the risk of cracking.

[0013] Therefore, by adopting the above technical solution, the present application selects galactomannan to modify the polyester resin, which can effectively improve the low-temperature flexibility of the hot melt adhesive, avoid the hot melt adhesive from becoming brittle in a low-temperature environment, and thus reduce the risk of cracking.

[0014] Optionally, the plasticizer is dioctyl phthalate.

[0015] Optionally, the antioxidant is antioxidant 1010.

[0016] In the second aspect, the present application provides a method for preparing the hot melt adhesive for bonding the above-mentioned LED backlight TV light strips, comprising the following steps: adding modified polyester resin, graphene, hexagonal boron nitride nanosheets, rosin resin, plasticizer and antioxidant into a mixer, mixing under nitrogen protection, extruding and granulating, and obtaining the hot melt adhesive for bonding the LED backlight TV light strips.

[0017] By adopting the above technical solution, the preparation method of the present application is simple and suitable for industrial promotion.

[0018] Optionally, the mixing speed is 50-60 rpm, the mixing temperature is 230-236° C., and the mixing time is 1-2 h.

[0019] In summary, the present invention includes at least one of the following beneficial technical effects: 1. This application uses modified polyester resin as the base material, which provides adhesive properties. The modified polyester resin has good thermal stability, temperature resistance and good chemical stability; graphene has extremely high thermal conductivity, which can significantly improve the thermal conductivity of hot melt adhesive, help LED light strips to better dissipate heat and extend service life; hexagonal boron nitride nanosheets are also a high-performance thermal conductive filler, which not only has good insulation properties, but also has good thermal conductivity, which can enhance the thermal conductivity of hot melt adhesive; rosin resin, as a kind of adhesive, can improve the bonding properties of hot melt adhesive, increase initial adhesion, and help improve the wettability and adhesion of hot melt adhesive; plasticizers can lower the glass transition temperature of hot melt adhesive, making it easier to flow at lower temperatures, while increasing its flexibility and ductility and reducing brittleness; antioxidants can prevent oxidative degradation of hot melt adhesive during heating and extend its service life.

[0020] 2. The present application uses galactomannan to modify the polyester resin, which can effectively improve the low-temperature flexibility of the hot melt adhesive, avoid the hot melt adhesive from becoming brittle in a low-temperature environment, and thus reduce the risk of cracking.

[0021] 3. The preparation method of this application is simple and suitable for industrial promotion. DETAILED DESCRIPTION

[0022] The present application provides a hot melt adhesive for bonding LED backlight TV light strips, comprising the following components in parts by weight: 40-65 parts of modified polyester resin, 1-8 parts of graphene, 1-8 parts of hexagonal boron nitride nanosheets, 9-15 parts of rosin resin, 0.5-1.5 parts of plasticizer and 0.1-1 part of antioxidant.

[0023] The present application provides a method for preparing the hot melt adhesive for bonding the above-mentioned LED backlight TV light strips, comprising the following steps: adding modified polyester resin, graphene, hexagonal boron nitride nanosheets, rosin resin, plasticizer, and antioxidant into a mixer, mixing under nitrogen protection, and then extruding and granulating to obtain the hot melt adhesive for bonding the LED backlight TV light strips.

[0024] The technical solution of the present application will be further described below with specific preparation examples and examples. It should be noted that the polyester resin used in the following preparation examples and comparative examples is BASF PES E2010.

[0025] Preparation Example 1 This preparation example provides a modified polyester resin, and the preparation method thereof comprises the following steps: S1. Put the polyester resin into the hot melt adhesive machine for melting and cool it to 76°C; S2, add galactomannan, heat up and stir quickly until wire drawing occurs, add epoxidized soybean oil and talcum powder, stir evenly and heat in an oil bath at 186°C for 2.5h; S3, after cooling to room temperature, adding 3-pentanone and mixing and stirring to obtain the modified polyester resin.

[0026] The weight ratio of polyester resin, galactomannan, epoxidized soybean oil, talc and 3-pentanone is 100:26:10:3:1.

[0027] Preparation Example 2 This preparation example provides a modified polyester resin, and the preparation method thereof comprises the following steps: S1. Put the polyester resin into the hot melt adhesive machine for melting and cool it down to 75℃; S2, add galactomannan, heat up and stir quickly until wire drawing occurs, add epoxidized soybean oil and talcum powder, stir evenly and heat in an oil bath at 185°C for 3h; S3, after cooling to room temperature, adding 3-pentanone and mixing and stirring to obtain the modified polyester resin.

[0028] The weight ratio of polyester resin, galactomannan, epoxidized soybean oil, talc and 3-pentanone is 100:20:7:2:1.

[0029] Preparation Example 3 This preparation example provides a modified polyester resin, and the preparation method thereof comprises the following steps: S1. Put the polyester resin into the hot melt adhesive machine for melting and cool it to 78°C; S2, add galactomannan, heat up and stir quickly until wire drawing occurs, add epoxidized soybean oil and talcum powder, stir evenly and heat in an oil bath at 190°C for 2h; S3, after cooling to room temperature, adding 3-pentanone and mixing and stirring to obtain the modified polyester resin.

[0030] The weight ratio of polyester resin, galactomannan, epoxidized soybean oil, talc and 3-pentanone is 100:30:12:4:1. Specific embodiments

[0031] Example 1 A hot melt adhesive for bonding LED backlight TV light strips comprises the following components in parts by weight: 40 parts of modified polyester resin, 1 part of graphene, 1 part of hexagonal boron nitride nanosheets, 9 parts of rosin resin, 0.5 parts of plasticizer and 0.1 parts of antioxidant.

[0032] The modified polyester hot melt is prepared by Preparation Example 1, the plasticizer is dioctyl phthalate, and the antioxidant is antioxidant 1010.

[0033] A method for preparing a hot melt adhesive for bonding LED backlight TV light strips comprises the following steps: adding modified polyester resin, graphene, hexagonal boron nitride nanosheets, rosin resin, plasticizer, and antioxidant into a mixer, mixing under nitrogen protection, and then extruding and granulating to obtain the hot melt adhesive for bonding LED backlight TV light strips.

[0034] The mixing speed was 50 rpm, the mixing temperature was 230°C, the mixing time was 2 h, and the extrusion granulation temperature was 235°C.

[0035] Example 2 A hot melt adhesive for bonding LED backlight TV light strips comprises the following components in parts by weight: 55 parts of modified polyester resin, 4 parts of graphene, 3 parts of hexagonal boron nitride nanosheets, 11 parts of rosin resin, 1 part of plasticizer and 0.6 part of antioxidant.

[0036] The modified polyester hot melt is prepared by Preparation Example 1, the plasticizer is dioctyl phthalate, and the antioxidant is antioxidant 1010.

[0037] A method for preparing a hot melt adhesive for bonding LED backlight TV light strips comprises the following steps: adding modified polyester resin, graphene, hexagonal boron nitride nanosheets, rosin resin, plasticizer, and antioxidant into a mixer, mixing under nitrogen protection, and then extruding and granulating to obtain the hot melt adhesive for bonding LED backlight TV light strips.

[0038] The mixing speed was 55 rpm, the mixing temperature was 233° C., the mixing time was 1.5 h, and the extrusion granulation temperature was 238° C.

[0039] Example 3 A hot melt adhesive for bonding LED backlight TV light strips comprises the following components in parts by weight: 65 parts of modified polyester resin, 8 parts of graphene, 8 parts of hexagonal boron nitride nanosheets, 15 parts of rosin resin, 1.5 parts of plasticizer and 1 part of antioxidant.

[0040] The modified polyester resin is prepared according to Preparation Example 1, the plasticizer is dioctyl phthalate, and the antioxidant is antioxidant 1010.

[0041] A method for preparing a hot melt adhesive for bonding LED backlight TV light strips comprises the following steps: adding modified polyester resin, graphene, hexagonal boron nitride nanosheets, rosin resin, plasticizer, and antioxidant into a mixer, mixing under nitrogen protection, and then extruding and granulating to obtain the hot melt adhesive for bonding LED backlight TV light strips.

[0042] The mixing speed was 60 rpm, the mixing temperature was 236°C, the mixing time was 1 h, and the extrusion granulation temperature was 240°C.

[0043] Example 4 The difference between this embodiment and embodiment 2 is that a hot melt adhesive for bonding LED backlight TV light strips comprises the following components in parts by weight: 50 parts of modified polyester resin, 3 parts of graphene, 2 parts of hexagonal boron nitride nanosheets, 10 parts of rosin resin, 0.9 parts of plasticizer and 0.5 parts of antioxidant.

[0044] The modified polyester resin is prepared according to Preparation Example 1, the plasticizer is dioctyl phthalate, and the antioxidant is antioxidant 1010.

[0045] A method for preparing a hot melt adhesive for bonding LED backlight TV light strips comprises the following steps: adding modified polyester resin, graphene, hexagonal boron nitride nanosheets, rosin resin, plasticizer, and antioxidant into a mixer, mixing under nitrogen protection, and then extruding and granulating to obtain the hot melt adhesive for bonding LED backlight TV light strips.

[0046] The mixing speed was 55 rpm, the mixing temperature was 233° C., the mixing time was 1.5 h, and the extrusion granulation temperature was 238° C.

[0047] Example 5 A hot melt adhesive for bonding LED backlight TV light strips comprises the following components in parts by weight: 58 parts of modified polyester resin, 5 parts of graphene, 5 parts of hexagonal boron nitride nanosheets, 12 parts of rosin resin, 12 parts of plasticizer and 0.8 parts of antioxidant.

[0048] The modified polyester resin is prepared according to Preparation Example 1, the plasticizer is dioctyl phthalate, and the antioxidant is antioxidant 1010.

[0049] A method for preparing a hot melt adhesive for bonding LED backlight TV light strips comprises the following steps: adding modified polyester resin, graphene, hexagonal boron nitride nanosheets, rosin resin, plasticizer, and antioxidant into a mixer, mixing under nitrogen protection, and then extruding and granulating to obtain the hot melt adhesive for bonding LED backlight TV light strips.

[0050] The mixing speed was 55 rpm, the mixing temperature was 233° C., the mixing time was 1.5 h, and the extrusion granulation temperature was 238° C.

[0051] Example 6 The difference between this embodiment and embodiment 2 is that the modified polyester resin is prepared by preparation example 2.

[0052] Example 7 The difference between this embodiment and embodiment 2 is that the modified polyester resin is prepared by preparation example 3.

[0053] Comparative Example 1 The difference between this embodiment and embodiment 2 is that an equal amount of unmodified polyester resin (BASF PESE2010) is used to replace the modified polyester resin.

[0054] Comparative Example 2 The difference between this embodiment and embodiment 2 is that graphene is not added.

[0055] Comparative Example 3 The difference between this embodiment and embodiment 2 is that no hexagonal boron nitride nanosheets are added.

[0056] Comparative Example 4 The difference between this embodiment and embodiment 2 is that no rosin resin is added.

[0057] Experimental testing The shear strength test and low temperature flexibility test were performed on Examples 1-7 and Comparative Examples 1-4. The test results are shown in Table 1.

[0058] 1. Shear strength test: The hot melt adhesive products prepared in each embodiment and comparative example were heated and melted to prepare samples. The sample preparation steps were as follows: the melted hot melt adhesive was coated between two steel plates, pressed for 5 minutes, and then the pressure was removed and left to stand for 12 hours. The shear strength of the sample was tested in accordance with GB / T 7124-2008 Determination of tensile shear strength of adhesives (rigid material to rigid material), the breaking load was measured, and the shear strength was calculated based on the shear area, and the results were recorded in Table 1.

[0059] 2. Low temperature flexibility test: Referring to "HG / T 4222-2011 Hot Melt Adhesive Low Temperature Flexibility Test Method", the hot melt adhesives in each embodiment and comparative example were made into several hot melt adhesive sheets, the size of the hot melt adhesive sheets was 75mm×10mm×1.25mm, and 20 samples of the hot melt adhesive sheets corresponding to each embodiment and comparative example were taken. All samples and test devices were stored at -20℃ for 24h, and then placed in an environment of (23±2)℃ and relative humidity of 50%±5% for more than 24 hours for state adjustment, and then referred to "HG / T The test was carried out in accordance with Section 8 of "4222-2011 Hot Melt Adhesive Low Temperature Flexibility Test Method", and the tests were carried out in descending order of mandrel diameter (25.6mm, 12.8m, 6.4mm, 3.2mmm). In each group of experiments, each mandrel diameter was repeated with 5 specimens, and the mandrel diameter with the smallest diameter that 4 out of 5 specimens passed was recorded as the flexibility of the hot melt adhesive.

[0060] 3. Thermal conductivity: The hot melt adhesives in the embodiments and comparative examples were made into hot melt adhesive sheets, and then the thermal conductivity of different hot melt adhesive sheets was tested according to ISO22007-2.

[0061] Table 1 Example Shear strength(MPa) Mandrel diameter (mm) Thermal conductivity (W / mk) Example 1 3.57 3.2 0.90 Example 2 4.04 3.2 0.95 Example 3 3.30 3.2 0.97 Example 4 3.63 3.2 0.89 Example 5 3.78 3.2 0.92 Example 6 3.72 3.2 0.94 Example 7 3.69 3.2 0.93 Comparative Example 1 3.11 6.4 0.82 Comparative Example 2 2.75 3.2 0.64 Comparative Example 3 2.81 3.2 0.70 Comparative Example 4 2.90 6.4 0.84 Results Analysis The hot melt adhesive prepared according to the present application has better thermal conductivity, bonding performance and low temperature resistance.

[0062] Combining Example 2 with Comparative Example 1 and the data in Table 1, it can be seen that the present application uses galactomannan to modify the polyester resin. The large number of hydroxyl groups contained in the galactomannan molecular chain can form hydrogen bonds or other intermolecular forces with the surface of the polar material, thereby forming a stable bonding interface between the hot melt adhesive molecules and the surface of the polar material, and maintaining a high bonding strength even at a relatively low temperature.

[0063] Combining Example 2 with Comparative Example 2 and the data in Table 1, it can be seen that graphene has extremely high thermal conductivity, which can significantly improve the thermal conductivity of the hot melt adhesive, help the LED light strip to better dissipate heat and extend its service life.

[0064] Combining Example 2 with Comparative Example 3 and the data in Table 1, it can be seen that hexagonal boron nitride nanosheets are also a high-performance thermal conductive filler, which not only has excellent insulation properties but also has good thermal conductivity, and can enhance the thermal conductivity of the hot melt adhesive.

[0065] Combining Example 2 with Comparative Example 4 and the data in Table 1, it can be seen that rosin resin, as a kind of adhesive, can improve the bonding performance of hot melt adhesive, increase the initial adhesion, and help to improve the wettability and adhesion of hot melt adhesive.

[0066] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A hot melt adhesive for bonding LED backlight TV light strips, characterized in that: The invention comprises the following components in parts by weight: 40-65 parts of modified polyester resin, 1-8 parts of graphene, 1-8 parts of hexagonal boron nitride nanosheets, 9-15 parts of rosin resin, 0.5-1.5 parts of plasticizer and 0.1-1 parts of antioxidant, wherein the modified polyester resin is prepared by modifying polyester resin by galactomannan.

2. The hot melt adhesive for bonding LED backlight TV light strips according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 50-58 parts of modified polyester resin, 3-5 parts of graphene, 2-5 parts of hexagonal boron nitride nanosheets, 10-12 parts of rosin resin, 0.9-12 parts of plasticizer and 0.5-0.8 parts of antioxidant.

3. The hot melt adhesive for bonding LED backlight TV light strips according to claim 1, characterized in that: The modified polyester resin comprises the following raw materials: polyester resin, galactomannan, epoxidized soybean oil, talc and 3-pentanone.

4. The hot melt adhesive for bonding LED backlight TV light strips according to claim 3, characterized in that: The weight ratio of the polyester resin, galactomannan, epoxidized soybean oil, talc and 3-pentanone is 100:(20-30):(7-12):(2-4):

1.

5. The hot melt adhesive for bonding LED backlight TV light strips according to claim 4, characterized in that: The preparation method of the modified polyester resin comprises the following steps: S1, melt the polyester resin first, and then cool it to 75-78°C; S2, add galactomannan to the material of S1, heat up and stir rapidly, add epoxidized soybean oil and talcum powder when wire drawing occurs, stir evenly and heat in an oil bath; S3, after cooling to room temperature, adding 3-pentanone to the material in S2 and mixing and stirring to obtain the modified polyester resin.

6. The hot melt adhesive for bonding LED backlight TV light strips according to claim 1, characterized in that: In S2, the temperature of the oil bath heating is 185-190°C and the time is 2-3h.

7. The hot melt adhesive for bonding LED backlight TV light strips according to claim 1, characterized in that: The plasticizer is dioctyl phthalate.

8. The hot melt adhesive for bonding LED backlight TV light strips according to claim 1, characterized in that: The antioxidant is antioxidant 1010.

9. A method for preparing the hot melt adhesive for bonding LED backlight TV light strips according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing modified polyester resin, graphene, hexagonal boron nitride nanosheets, rosin resin, plasticizer and antioxidant under nitrogen protection, extruding and granulating to obtain the hot melt adhesive for bonding LED backlight TV light strips.

10. The method for preparing the hot melt adhesive for bonding LED backlight TV light strips according to claim 9, characterized in that: The mixing speed is 50-60 rpm, the mixing temperature is 230-236°C, and the mixing time is 1-2h.