Waterproof sealing chip hot melt adhesive and preparation method thereof

Abstract

The invention relates to a waterproof sealing chip hot melt adhesive and a preparation method thereof, and relates to the field of hot melt adhesives. The invention relates to a waterproof sealing chip hot melt adhesive, which comprises the following raw materials by weight: 20-35 parts of crystalline polyol; 30 to 45 parts of amorphous polyol containing a benzene ring structure; 2-7 parts of castor oil; 10 to 18 parts of aromatic diisocyanate; 2 to 4 parts of 3-isocyanate propyl triethoxy silane; 0.2 to 0.5 part of a catalyst; 4-9 parts of terpene phenolic resin; and 1-2 parts of an antioxidant. According to the packaging structure, the high temperature resistance and the waterproof performance of the hot melt adhesive can be improved, and the sealing performance and the reliability of the packaging structure in a high-temperature or humid environment are ensured.

Description

Technical Field

[0001] The invention relates to the field of hot melt adhesives, and in particular to a waterproof sealing chip hot melt adhesive and a preparation method thereof. Background Art

[0002] Hot melt adhesive is a plastic adhesive. Its physical form changes with temperature within a certain temperature range, but its chemical properties remain unchanged. With environmental awareness, solvent-free hot melt adhesive is favored because it does not produce organic volatiles during use. Solvent-free hot melt adhesive can melt into a viscous liquid when heated to a certain temperature. After wetting the adherend, it can achieve adhesion when cooled to room temperature.

[0003] Hot melt adhesives can be divided into several categories, including ethylene-vinyl acetate, polyester, polyamide and polyurethane. Among them, polyurethane hot melt adhesives have good toughness, excellent low temperature resistance, easy application, strong bonding force, and a wide range of bonding substrates. They are widely used in the fields of construction, textiles, electronics, machinery manufacturing, aerospace, etc. In the field of electronics, polyurethane hot melt adhesives can be used for chip packaging and protection, bonding and fixing chips on substrates to achieve sealing and protection.

[0004] The existing polyurethane hot melt adhesive has poor high temperature resistance and waterproof effect when bonding chips. The chip may generate high temperature or be exposed to humid and rainy environment when in use. Moisture entering the chip may cause short circuit, component corrosion, etc., affecting the sealing and reliability of the packaging structure in high temperature or humid environment. Summary of the invention

[0005] In order to improve the high temperature resistance and waterproofness of the hot melt adhesive and ensure the sealing and reliability of the packaging structure in a high temperature or humid environment, the present application provides a waterproof sealing chip hot melt adhesive and a preparation method thereof.

[0006] The present application provides a waterproof sealing chip hot melt adhesive and a preparation method thereof using the following technical solutions: A waterproof sealing chip hot melt adhesive, comprising the following raw materials in parts by weight: 20-35 parts of crystalline polyol; 30-45 parts of non-crystalline polyol containing benzene ring structure; 2-7 parts of castor oil; 10-18 parts of aromatic diisocyanate; 2-4 parts of 3-isocyanatepropyltriethoxysilane; Catalyst 0.2-0.5 parts; 4-9 parts of terpene phenolic resin; 1-2 servings of antioxidants.

[0007] Adopting the above technical scheme, the present application selects a combination of crystalline polyols, non-crystalline polyols containing benzene ring structures, and castor oil. The crystalline polyols are beneficial to improving the initial adhesion strength of the hot melt adhesive, while the non-crystalline polyols containing benzene ring structures are beneficial to improving the flexibility and open time of the hot melt adhesive. The introduction of benzene ring structures and benzene rings in aromatic diisocyanates enhances the heat resistance. Castor oil replaces part of the petroleum-based polyols, which is beneficial to improving the waterproof performance of the hot melt adhesive. Through appropriate proportions, the polyurethane hot melt adhesive has excellent initial adhesion strength and final adhesion strength, as well as excellent flexibility, high temperature resistance and waterproof performance.

[0008] By using 3-isocyanate propyl triethoxysilane to end-cap the hot melt adhesive, a Si-O-SI network structure is formed during the cross-linking and curing process, which is beneficial to improving the water resistance and heat resistance of the hot melt adhesive. At the same time, the isocyanate group contained in it participates in the curing, which improves the bonding strength; terpene phenolic resin is used as a tackifying resin, and the system has good compatibility, which can modify the initial viscosity and temperature resistance of the hot melt adhesive. The polyurethane hot melt adhesive prepared in this application has excellent high temperature resistance and waterproofness, and is suitable for chip packaging and sealing protection.

[0009] Furthermore, the castor oil is modified castor oil, and the modified castor oil is prepared from the following raw materials in parts by weight: 50-60 parts of castor oil; 7-12 parts of mercaptoethanol; 4-6 parts of azobisisobutyronitrile; Glycerin 9-12 parts; Sodium hydroxide 0.05-0.1 parts.

[0010] By adopting the above technical scheme, castor oil is modified with mercaptoethanol and glycerol to introduce hydroxyl functional groups, which is beneficial to improve the reaction with aromatic diisocyanates and increase the crosslinking density, thereby improving the bonding strength. At the same time, the modified castor oil reduces the reaction with water molecules and is more adaptable to humid and high-temperature environments.

[0011] Furthermore, the crystalline polyol is selected from one or more of poly 1,6-hexanediol adipate diol, poly 1,4-butylene adipate diol, polyethylene adipate diol, and poly 2,3-dimethyl-2,3-butylene glycol.

[0012] Furthermore, the non-crystalline polyol containing a benzene ring structure is selected from one or more of polyester polyols of phthalic acid / neopentyl glycol, polyester polyols of adipic acid / isophthalic acid / hexanediol, polyester polyols of isophthalic acid / hexanediol / neopentyl glycol, and polyester polyols of adipic acid / terephthalic acid / phthalic acid / ethylene glycol.

[0013] By adopting the above technical scheme, a polyacid containing a benzene ring structure is selected to react with a diol, and a benzene ring is introduced into the polyester polyol to improve heat resistance and corrosion resistance.

[0014] Furthermore, the non-crystalline polyol containing a benzene ring structure is made from the following raw materials: adipic acid, terephthalic acid, trimellitic anhydride, neopentyl glycol, p-toluenesulfonic acid and triphenyl phosphite, wherein the molar ratio of adipic acid, terephthalic acid, trimellitic anhydride and neopentyl glycol is 3-3.5:1:0.8-1:6-9, and the masses of p-toluenesulfonic acid and triphenyl phosphite are 300-600ppm and 100-200ppm of the total acid mass, respectively.

[0015] By adopting the above technical scheme, p-toluenesulfonic acid is selected as a catalyst and triphenyl phosphite is used as a stabilizer. Terephthalic acid and trimellitic anhydride are introduced into the aliphatic polyester polyol prepared from adipic acid and neopentyl glycol, so that the chain segments are relatively random and have low crystallinity, so that the polyurethane hot melt adhesive has a long open time and high bonding strength.

[0016] Furthermore, the aromatic diisocyanate is selected from one or more of diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, toluene diisocyanate, and diphenylmethylene diisocyanate.

[0017] By adopting the above technical solution, the diisocyanate has a benzene ring, so that the heat resistance is improved.

[0018] Furthermore, the catalyst is selected from one or more of dibutyltin dilaurate, triethylenediamine, and dimorpholinyl diethyl ether.

[0019] The present application also provides a method for preparing a waterproof sealing chip hot melt adhesive, comprising the following steps: Put crystalline polyol, non-crystalline polyol containing benzene ring structure, castor oil and terpene phenolic resin into a reaction kettle, heat to 100-130°C, and vacuum dehydrate for 2-3h under stirring, with a vacuum degree of -0.01-0.05MPa; Cool down to 70-75℃, add catalyst and aromatic isocyanate into the reactor, pass nitrogen protection, raise the temperature to 80-90℃ and react for 2-3h; Add 3-isocyanatepropyltrimethoxysilane and antioxidant into the reaction kettle, stir and mix at 115-125° C. for 0.5-1 h under nitrogen protection, perform vacuum degassing for 1-1.5 h, discharge the material, and seal and package under nitrogen protection.

[0020] By adopting the above technical scheme, the preparation method is simple and environmentally friendly, without volatile organic compounds, and a moisture-curing polyurethane hot melt adhesive with high bonding strength, high temperature resistance and waterproofness is obtained.

[0021] Further, when castor oil is modified castor oil, it is prepared by the following steps: Castor oil and mercaptoethanol are mixed and placed in a reaction kettle, and the mixture is heated to 75-80°C under nitrogen protection, and azobisisobutyronitrile is added to react for 3-4 hours, and the mixture is heated to 100-105°C and reacted for 2-2.5 hours, and ethyl acetate is added to the mixture, and the mixture is washed with brine and water, and dried with anhydrous magnesium sulfate, and the ethyl acetate is evaporated to obtain an intermediate; The intermediate and glycerol are added into a mixing kettle, sodium hydroxide is added under stirring, the temperature is raised to 170-180° C., and the mixture is reacted for 1-2 hours under nitrogen protection to obtain modified castor oil.

[0022] By adopting the technical scheme, the preparation method is simple and the yield is high, and the modified castor oil with moisture and heat resistance is obtained.

[0023] Further, the non-crystalline polyol containing a benzene ring structure is prepared by the following steps: Adipic acid, terephthalic acid, trimellitic anhydride, neopentyl glycol, p-toluenesulfonic acid and triphenyl phosphite are put into a polymerization kettle, and the temperature is raised to 170-200°C under nitrogen protection. After 60%-70% of water is removed by heat preservation, the temperature is continuously raised by 10°C. When the temperature reaches 220-230°C, heat preservation is started and the acid value is measured. When the acid value of the material is lower than 15 mgKOH / g, vacuuming is started and the temperature is maintained at 220°C-230°C. When the acid value is ≤2 mgKOH / g and the hydroxyl value is 30-100 mgKOH / g, the reaction is stopped, the temperature is lowered and the material is discharged to obtain a non-crystalline polyol containing a benzene ring structure.

[0024] By adopting the above technical scheme, the preparation process is improved to make the preparation process more stable and controllable, and a non-crystalline polyol containing a benzene ring structure with controllable hydroxyl value and acid ester is obtained.

[0025] In summary, this application has the following beneficial effects: 1. The present application selects a combination of crystalline polyols, non-crystalline polyols containing a benzene ring structure, and castor oil. The crystalline polyols are beneficial to improving the initial adhesion strength of the hot melt adhesive, while the non-crystalline polyols containing a benzene ring structure are beneficial to improving the flexibility and open time of the hot melt adhesive. The introduction of the benzene ring structure and the benzene ring in the aromatic diisocyanate enhances the heat resistance. Castor oil replaces part of the petroleum-based polyol, which is beneficial to improving the waterproof performance of the hot melt adhesive. Through appropriate proportions, the polyurethane hot melt adhesive has excellent initial adhesion strength and final adhesion strength, as well as excellent flexibility, high temperature resistance and waterproof performance.

[0026] By using 3-isocyanate propyl triethoxysilane to end-cap the hot melt adhesive, a Si-O-SI network structure is formed during the cross-linking and curing process, which is beneficial to improving the water resistance and heat resistance of the hot melt adhesive. At the same time, the isocyanate group contained in it participates in the curing, which improves the bonding strength; terpene phenolic resin is used as a tackifying resin, and the system has good compatibility, which can modify the initial viscosity and temperature resistance of the hot melt adhesive. The polyurethane hot melt adhesive prepared in this application has excellent high temperature resistance and waterproofness, and is suitable for chip packaging and sealing protection.

[0027] 2. Modifying castor oil with mercaptoethanol and glycerol and introducing hydroxyl functional groups are beneficial to improving the reaction with aromatic diisocyanates and increasing the cross-linking density, thereby improving the bonding strength. At the same time, the modified castor oil reduces the reaction with water molecules and is more adaptable in humid and high-temperature environments. DETAILED DESCRIPTION

[0028] The present application is further described in detail below.

[0029] Preparation Example Preparation Example 1 Modified castor oil is prepared from the following raw materials in parts by weight: 50 parts of castor oil; 7 parts of mercaptoethanol; 4 parts of azobisisobutyronitrile; Glycerin 9 parts; 0.05 parts of sodium hydroxide.

[0030] Modified castor oil is prepared by the following steps: Castor oil and mercaptoethanol were mixed and placed in a reaction kettle, heated to 75°C with nitrogen protection, azobisisobutyronitrile was added to react for 3 hours, the temperature was raised to 100°C and the reaction was continued for 2 hours, the temperature was lowered and ethyl acetate was added, the mixture was washed three times with brine and water respectively, dried with anhydrous magnesium sulfate, and the ethyl acetate was evaporated to obtain an intermediate; The intermediate and glycerol were added into a mixing kettle, sodium hydroxide was added under stirring, the temperature was raised to 170°C, and the mixture was reacted for 1 hour under nitrogen protection to obtain modified castor oil.

[0031] Preparation Example 2 Modified castor oil is prepared from the following raw materials in parts by weight: 60 parts of castor oil; 12 parts of mercaptoethanol; 6 parts of azobisisobutyronitrile; Glycerin 12 parts; 0.1 parts of sodium hydroxide.

[0032] Modified castor oil is prepared by the following steps: Castor oil and mercaptoethanol were mixed and placed in a reaction kettle, heated to 80°C under nitrogen protection, azobisisobutyronitrile was added to react for 4 hours, the temperature was raised to 105°C and the reaction was continued for 2.5 hours, the temperature was lowered and ethyl acetate was added, the mixture was washed three times with brine and water respectively, dried with anhydrous magnesium sulfate, and the ethyl acetate was evaporated to obtain an intermediate; The intermediate and glycerol were added into a mixing kettle, sodium hydroxide was added under stirring, the temperature was raised to 180°C, and the mixture was reacted for 2 hours under nitrogen protection to obtain modified castor oil.

[0033] Preparation Example 3 Non-crystalline polyols containing benzene ring structures are made from the following raw materials: Adipic acid, terephthalic acid, trimellitic anhydride, neopentyl glycol, wherein the molar ratio of adipic acid: terephthalic acid: trimellitic anhydride: neopentyl glycol is 3:1:0.8:6; p-Toluenesulfonic acid, 300 ppm based on the total acid mass; Triphenyl phosphite, the mass is 100ppm of the total mass of acid.

[0034] The non-crystalline polyol containing a benzene ring structure is prepared by the following steps: Adipic acid, terephthalic acid, trimellitic anhydride, neopentyl glycol, p-toluenesulfonic acid and triphenyl phosphite are put into a polymerization kettle, and the temperature is raised to 170°C under nitrogen protection. After 60% of dehydration is achieved by heat preservation, the temperature is continuously raised by 10°C, and the temperature is kept at 220°C to measure the acid value. When the acid value of the material is lower than 15 mgKOH / g, vacuuming is started and the temperature is maintained at 220°C. When the acid value is ≤2 mgKOH / g and the hydroxyl value is between 30 and 100 mgKOH / g, the reaction is stopped, the temperature is lowered and the material is discharged to obtain a non-crystalline polyol containing a benzene ring structure.

[0035] Preparation Example 4 Non-crystalline polyols containing benzene ring structures are made from the following raw materials: Adipic acid, terephthalic acid, trimellitic anhydride, neopentyl glycol, wherein the molar ratio of adipic acid: terephthalic acid: trimellitic anhydride: neopentyl glycol is 3.5:1:1:9; p-Toluenesulfonic acid, 600 ppm of the total acid mass; Triphenyl phosphite, the mass is 200ppm of the total mass of acid.

[0036] The non-crystalline polyol containing a benzene ring structure is prepared by the following steps: Adipic acid, terephthalic acid, trimellitic anhydride, neopentyl glycol, p-toluenesulfonic acid and triphenyl phosphite are put into a polymerization kettle, and the temperature is raised to 200°C under nitrogen protection. After 70% of dehydration is achieved by heat preservation, the temperature is continuously raised by 10°C, and the temperature is kept at 230°C to measure the acid value. When the acid value of the material is lower than 15 mgKOH / g, vacuuming is started and the temperature is maintained at 230°C. When the acid value is ≤2 mgKOH / g and the hydroxyl value is between 30 and 100 mgKOH / g, the reaction is stopped, the temperature is lowered and the material is discharged to obtain a non-crystalline polyol containing a benzene ring structure. Example

[0037] Example 1 The waterproof sealing chip hot melt adhesive includes the following raw materials in parts by weight: 20 parts of crystalline polyol, specifically poly(1,6-hexanediol adipate) diol with a molecular weight of 3000; 30 parts of non-crystalline polyol containing a benzene ring structure, specifically a polyester polyol of phthalic acid / neopentyl glycol with a molecular weight of 1000; 2 parts castor oil; 10 parts of aromatic diisocyanate, specifically diphenylmethane diisocyanate; 2 parts of 3-isocyanatepropyltriethoxysilane; 0.2 parts of catalyst, specifically dibutyltin dilaurate; 4 parts of terpene phenolic resin, purchased from Nantong Runfeng Petrochemical Co., Ltd.; 1 part of antioxidant, specifically antioxidant 1010.

[0038] The preparation method of the waterproof sealing chip hot melt adhesive comprises the following steps: Put crystalline polyol, non-crystalline polyol containing benzene ring structure, castor oil and terpene phenolic resin into a reaction kettle, heat to 100°C, and dehydrate under vacuum for 2 hours with stirring, and the vacuum degree is -0.01MPa; The temperature was lowered to 70°C, and the catalyst and aromatic isocyanate were added to the reactor. The reactor was protected by nitrogen and heated to 80°C for reaction for 2h. 3-isocyanatepropyltrimethoxysilane and antioxidant were added to the reactor, and the mixture was stirred at 115°C for 0.5h under nitrogen protection. The mixture was vacuum degassed for 1h, and the material was discharged and sealed under nitrogen protection.

[0039] Example 2 The waterproof sealing chip hot melt adhesive includes the following raw materials in parts by weight: 35 parts of crystalline polyol, specifically poly(1,4-butylene adipate) diol having a molecular weight of 2000; 45 parts of a non-crystalline polyol containing a benzene ring structure, specifically a polyester polyol of adipic acid / isophthalic acid / hexanediol with a molecular weight of 1500; 7 parts of castor oil; 18 parts of aromatic diisocyanate, specifically toluene diisocyanate; 4 parts of 3-isocyanatepropyltriethoxysilane; 0.5 parts of catalyst, specifically triethylenediamine; 9 parts of terpene phenolic resin, purchased from Nantong Runfeng Petrochemical Co., Ltd.; 2 parts of antioxidant, specifically antioxidant 1076 is selected.

[0040] The preparation method of the waterproof sealing chip hot melt adhesive comprises the following steps: Put crystalline polyol, non-crystalline polyol containing benzene ring structure, castor oil and terpene phenolic resin into a reaction kettle, heat to 130°C, and dehydrate under vacuum for 3 hours with stirring, and the vacuum degree is -0.05MPa; The temperature was lowered to 75°C, and the catalyst and aromatic isocyanate were added to the reactor. The reaction was carried out under nitrogen protection and the temperature was raised to 90°C for reaction for 3 hours. 3-isocyanatepropyltrimethoxysilane and antioxidant were added to the reactor, and the mixture was stirred and mixed at 125°C for 1 hour under nitrogen protection. The mixture was vacuum degassed for 1.5 hours, and the material was discharged and sealed under nitrogen protection.

[0041] Example 3 The waterproof sealing chip hot melt adhesive includes the following raw materials in parts by weight: 28 parts of crystalline polyol, specifically poly 2,3-dimethyl-2,3-butanediol with a molecular weight of 2000; 38 parts of a non-crystalline polyol containing a benzene ring structure, specifically a polyester polyol of isophthalic acid / hexanediol / neopentyl glycol with a molecular weight of 2000; 5 parts of castor oil; 13 parts of aromatic diisocyanate, specifically 8 parts of carbodiimide-modified diphenylmethane diisocyanate and 5 parts of diphenylmethylene diisocyanate; 3 parts of 3-isocyanatepropyltriethoxysilane; 0.4 parts of a catalyst, specifically 0.2 parts of dibutyltin dilaurate and 0.2 parts of dimorpholinyl diethyl ether; 7 parts of terpene phenolic resin, purchased from Nantong Runfeng Petrochemical Co., Ltd.; 1.5 parts of antioxidant, specifically antioxidant 168 is selected.

[0042] The preparation method of the waterproof sealing chip hot melt adhesive comprises the following steps: Put crystalline polyol, non-crystalline polyol containing benzene ring structure, castor oil and terpene phenolic resin into a reaction kettle, heat to 110°C, and dehydrate under vacuum for 2.5 hours with stirring, and the vacuum degree is -0.03MPa; The temperature was lowered to 72°C, and the catalyst and aromatic isocyanate were added to the reactor. The reactor was protected by nitrogen and the temperature was raised to 85°C for reaction for 2.5 hours. 3-isocyanatepropyltrimethoxysilane and antioxidant were added into the reaction kettle, and the mixture was stirred at 120° C. for 1 h under nitrogen protection, and vacuum degassing was performed for 1 h. The material was discharged and sealed and packaged under nitrogen protection.

[0043] Example 4 The difference between this embodiment and embodiment 1 is that the raw materials of the hot melt adhesive for the waterproof sealing chip are different.

[0044] The castor oil of this embodiment is the modified castor oil obtained in Preparation Example 1.

[0045] Example 5 The difference between this embodiment and embodiment 1 is that the raw materials of the hot melt adhesive for the waterproof sealing chip are different.

[0046] The castor oil of this embodiment is the modified castor oil obtained in Preparation Example 2.

[0047] Example 6 The difference between this embodiment and embodiment 1 is that the raw materials of the hot melt adhesive for the waterproof sealing chip are different.

[0048] The non-crystalline polyol containing a benzene ring structure in this embodiment is the non-crystalline polyol containing a benzene ring structure prepared in Preparation Example 3.

[0049] Example 7 The difference between this embodiment and embodiment 1 is that the raw materials of the hot melt adhesive for the waterproof sealing chip are different.

[0050] The non-crystalline polyol containing a benzene ring structure in this embodiment is the non-crystalline polyol containing a benzene ring structure prepared in Preparation Example 4.

[0051] Example 8 The difference between this embodiment and embodiment 1 is that the raw materials of the hot melt adhesive for the waterproof sealing chip are different.

[0052] The castor oil of this embodiment is the modified castor oil prepared in Preparation Example 2, and the non-crystalline polyol containing a benzene ring structure of this embodiment is the non-crystalline polyol containing a benzene ring structure prepared in Preparation Example 3.

[0053] Comparative Example Comparative Example 1 The difference between this comparative example and Example 1 is that the raw materials of the hot melt adhesive for the waterproof sealing chip are different.

[0054] In the raw materials of the hot melt adhesive in this comparative example, castor oil was not added.

[0055] Comparative Example 2 The difference between this comparative example and Example 1 is that the raw materials of the hot melt adhesive for the waterproof sealing chip are different.

[0056] In the raw materials of the hot melt adhesive in this comparative example, no 3-isocyanate propyl triethoxy silane was added.

[0057] Comparative Example 3 The difference between this comparative example and Example 1 is that the raw materials of the hot melt adhesive for the waterproof sealing chip are different.

[0058] Among the raw materials of the hot melt adhesive in this comparative example, the polyol is 50 parts of poly(1,6-hexanediol adipate) with a molecular weight of 3000.

[0059] Performance Testing Preparation of bonding samples: After two standard bonding substrates were dusted and degreased, they were horizontally bonded with the hot melt adhesives prepared in Examples 1-8 and Comparative Examples 1-3, respectively. The bonding area was 12.5 mm × 25 mm, and the adhesive thickness was 0.2 mm. After bonding, they were cured at 25°C and 50% RH. The complete curing conditions were: 25°C, 50% RH × 7d.

[0060] The open time, bonding strength, high temperature resistance and water resistance of the hot melt adhesives prepared in the embodiments and comparative examples were tested.

[0061] Opening time: measured in accordance with standard HG / T 3716-2003; Bond strength: Refer to standard GB / T 7124-2008 and use a tensile testing machine to measure shear tensile strength; High temperature resistance: After the adhesive is cured for 24 hours, place the bonded sample in a 160℃ hot pressing mold and press for 5 minutes. Take it out and peel it off to observe the adhesive surface and the glue to determine whether there is softening and flowing of the adhesive layer. Waterproofness: The water contact angle is tested with reference to GB / T 30693-2014 standard.

[0062] Please see Table 1 below for a comparison of all test data.

[0063] Table 1 According to the data in Table 1, the moisture-curing polyurethane hot melt adhesive prepared in the present application has excellent bonding strength, a long open time, and excellent high temperature resistance and waterproofness. It can be used in high temperature or humid environments to ensure the sealing and possibility of chip packaging structure.

[0064] Compared with Examples 1-3, in Examples 4-5, castor oil is modified by using mercaptoethanol and glycerol, and hydroxyl functional groups are introduced into the castor oil, thereby increasing the crosslinking density of the polyurethane, increasing the bonding strength, and enhancing the water resistance.

[0065] Compared with Examples 1-3, Examples 6-7 use a specific structure of non-crystalline polyol containing a benzene ring structure prepared by the reaction of adipic acid, terephthalic acid, trimellitic anhydride, and neopentyl glycol, which makes the soft segment structure of the polyurethane hot melt adhesive more irregular, with a longer open time and higher bonding strength.

[0066] Compared with Example 1, in Comparative Examples 1-3, castor oil, 3-isocyanatepropyltriethoxysilane and non-crystalline polyol containing a benzene ring structure are missing from the raw materials of the polyurethane hot melt adhesive, which reduces the performance of the polyurethane hot melt adhesive, indicating the synergistic effect of the raw materials on the performance of the polyurethane hot melt adhesive.

[0067] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A waterproof sealing chip hot melt adhesive, characterized in that: The invention comprises the following raw materials in parts by weight: 20-35 parts of crystalline polyol; 30-45 parts of non-crystalline polyol containing benzene ring structure; 2-7 parts of castor oil; 10-18 parts of aromatic diisocyanate; 2-4 parts of 3-isocyanatepropyltriethoxysilane; Catalyst 0.2-0.5 parts; 4-9 parts of terpene phenolic resin; 1-2 servings of antioxidants.

2. A waterproof sealing chip hot melt adhesive according to claim 1, characterized in that: The castor oil is modified castor oil, and the modified castor oil is prepared from the following raw materials in parts by weight: 50-60 parts of castor oil; 7-12 parts of mercaptoethanol; 4-6 parts of azobisisobutyronitrile; Glycerin 9-12 parts; Sodium hydroxide 0.05-0.1 parts.

3. The waterproof sealing chip hot melt adhesive according to claim 1, characterized in that: The crystalline polyol is selected from one or more of poly 1,6-hexanediol adipate diol, poly 1,4-butylene adipate diol, polyethylene adipate diol, poly 2,3-dimethyl-2,3-butylene glycol.

4. The waterproof sealing chip hot melt adhesive according to claim 1, characterized in that: The non-crystalline polyol containing a benzene ring structure is selected from one or more of polyester polyols of phthalic acid / neopentyl glycol, polyester polyols of adipic acid / isophthalic acid / hexanediol, polyester polyols of isophthalic acid / hexanediol / neopentyl glycol, and polyester polyols of adipic acid / terephthalic acid / phthalic acid / ethylene glycol.

5. The waterproof sealing chip hot melt adhesive according to claim 4, characterized in that: The non-crystalline polyol containing a benzene ring structure is made of the following raw materials: adipic acid, terephthalic acid, trimellitic anhydride, neopentyl glycol, p-toluenesulfonic acid and triphenyl phosphite, wherein the molar ratio of adipic acid, terephthalic acid, trimellitic anhydride and neopentyl glycol is 3-3.5:1:0.8-1:6-9, and the masses of p-toluenesulfonic acid and triphenyl phosphite are 300-600ppm and 100-200ppm of the total acid mass, respectively.

6. The waterproof sealing chip hot melt adhesive according to claim 1, characterized in that: The aromatic diisocyanate is selected from one or more of diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, toluene diisocyanate, and diphenylmethylene diisocyanate.

7. The waterproof sealing chip hot melt adhesive according to claim 1, characterized in that: The catalyst is selected from one or more of dibutyltin dilaurate, triethylenediamine, and dimorpholinyl diethyl ether.

8. A method for preparing a waterproof sealing chip hot melt adhesive according to any one of claims 1 to 7, characterized in that: The following steps are involved: Put crystalline polyol, non-crystalline polyol containing benzene ring structure, castor oil and terpene phenolic resin into a reaction kettle, heat to 100-130°C, and vacuum dehydrate for 2-3h under stirring, with a vacuum degree of -0.01-0.05MPa; Cool down to 70-75℃, add catalyst and aromatic isocyanate into the reactor, pass nitrogen protection, raise the temperature to 80-90℃ and react for 2-3h; Add 3-isocyanatepropyltrimethoxysilane and antioxidant into the reaction kettle, stir and mix at 115-125° C. for 0.5-1 h under nitrogen protection, perform vacuum degassing for 1-1.5 h, discharge the material, and seal and package under nitrogen protection.

9. The method for preparing a waterproof sealing chip hot melt adhesive according to claim 8, characterized in that: When castor oil is modified castor oil, it is prepared by the following steps: Castor oil and mercaptoethanol are mixed and placed in a reaction kettle, and the mixture is heated to 75-80°C under nitrogen protection, and azobisisobutyronitrile is added to react for 3-4 hours, and the mixture is heated to 100-105°C and reacted for 2-2.5 hours, and ethyl acetate is added to the mixture, and the mixture is washed with brine and water, and dried with anhydrous magnesium sulfate, and the ethyl acetate is evaporated to obtain an intermediate; The intermediate and glycerol are added into a mixing kettle, sodium hydroxide is added under stirring, the temperature is raised to 170-180° C., and the mixture is reacted for 1-2 hours under nitrogen protection to obtain modified castor oil.

10. The method for preparing a waterproof sealing chip hot melt adhesive according to claim 8, characterized in that: The non-crystalline polyol containing a benzene ring structure is prepared by the following steps: Adipic acid, terephthalic acid, trimellitic anhydride, neopentyl glycol, p-toluenesulfonic acid and triphenyl phosphite are put into a polymerization kettle, and the temperature is raised to 170-200°C under nitrogen protection. After 60%-70% of water is removed by heat preservation, the temperature is continuously raised by 10°C. When the temperature reaches 220-230°C, heat preservation is started and the acid value is measured. When the acid value of the material is lower than 15 mgKOH / g, vacuuming is started and the temperature is maintained at 220°C-230°C. When the acid value is ≤2 mgKOH / g and the hydroxyl value is 30-100 mgKOH / g, the reaction is stopped, the temperature is lowered and the material is discharged to obtain a non-crystalline polyol containing a benzene ring structure.

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