Resin composition, two-component polyurethane pouring sealant as well as preparation method and application of two-component polyurethane pouring sealant

Abstract

The invention belongs to the technical field of electronic pouring sealants, and particularly relates to a resin composition, a two-component polyurethane pouring sealant as well as a preparation method and application of the two-component polyurethane pouring sealant. According to the invention, a reactive plasticizer, castor oil and polyether polyol are utilized to prepare a resin composition with a synergistic effect, and the resin composition is further mixed with a curing component to prepare the two-component polyurethane pouring sealant. The resin composition obviously enhances the weather resistance, the mechanical property, the transparency and the defoaming property of the pouring sealant. Wherein due to the existence of the castor oil, the pouring sealant shows an excellent anti-yellowing effect; the polyether polyol improves the overall strength and stability of the pouring sealant; due to the chemical bonding effect of the reactive plasticizer and a polyurethane chain segment, the precipitation of the plasticizer under the conditions of low temperature, high temperature, damp heat and exposure is effectively prevented. The two-component polyurethane pouring sealant with excellent weather resistance, mechanical property, transparency and defoaming property is prepared on the basis of the resin composition with specific components, and the application range of the two-component polyurethane pouring sealant under extreme environmental conditions is widened.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic potting adhesives, and more specifically, relates to a resin composition, a two-component polyurethane potting adhesive, and a preparation method and application thereof. Background Art

[0002] As an important polymer material, potting glue plays a key role in sealing, fixing and protecting components in electronic, electrical and mechanical equipment. Traditional polyurethane potting glue is widely used in many fields due to its excellent waterproof and dustproof performance, electrical insulation performance, good physical and mechanical properties, and easy processing and use.

[0003] However, with the advancement of science and technology and the increasing requirements for material performance, traditional polyurethane potting glue has also exposed some limitations, for example, its stability needs to be improved, the performance after curing is poor, and there are problems such as opacity and many bubbles. These problems limit the application of traditional polyurethane potting glue to a certain extent. In order to solve the above problems, Chinese patent application CN105907353A uses castor oil, isocyanate and non-reactive plasticizer with low price and excellent electronic insulation performance as main raw materials, and prepares an ultra-low hardness polyurethane potting glue with advantages such as environmental protection and no odor, few bubbles, aging resistance and yellowing resistance, and fast room temperature curing speed. However, although this scheme solves some problems of traditional polyurethane potting glue to a certain extent, the non-reactive plasticizer used still has the risk of precipitation, which may have an adverse effect on the performance of its comprehensive performance, and the problem of insufficient stability has not been completely solved. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of the prior art polyurethane potting glue, such as poor weather resistance, easy precipitation of plasticizer and poor stability, and provide a resin composition.

[0005] Another object of the present invention is to provide a two-component polyurethane potting adhesive.

[0006] Another object of the present invention is to provide a method for preparing the two-component polyurethane potting adhesive.

[0007] Another object of the present invention is to provide an application of the above resin composition or the above two-component polyurethane potting glue.

[0008] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0009] The present invention protects a resin composition, which comprises the following raw materials by weight: 70 to 90 parts of polymer polyol and 15 to 30 parts of reactive plasticizer;

[0010] Wherein, the polymer polyol comprises at least castor oil and polyether polyol;

[0011] The reactive plasticizer is a plasticizer having a hydroxyl group.

[0012] The resin composition of the present invention is usually used as the main component of the potting glue, playing multiple key roles. It can not only provide the necessary physical and chemical properties for the potting glue, but also significantly improve its fluidity and filling properties, thereby ensuring that the potting effect reaches the best state. The present invention particularly selects a reactive plasticizer, which significantly improves the weather resistance of the potting glue through chemical bonding, ensuring its long-term stability in a variety of complex environments. The presence of castor oil shows an excellent yellowing resistance effect and maintains the appearance quality of the potting glue; the polyether polyol significantly improves the overall strength and structural stability of the material. The synergistic effect of these three components not only comprehensively improves the potting glue and stability, but also significantly enhances its mechanical properties, such as hardness and tensile strength, while maintaining excellent transparency and defoaming properties. The polyurethane potting glue finally prepared has high weather resistance, excellent mechanical properties, high transparency and excellent defoaming properties, showing excellent comprehensive performance.

[0013] Furthermore, the castor oil is unmodified castor oil and / or modified castor oil.

[0014] Furthermore, the non-modified castor oil is a vegetable oil extracted from seeds of castor plants, and has a hydroxyl value of 155 to 170 KOH / g.

[0015] Furthermore, the unmodified castor oil includes one or more of extra-grade castor oil, refined-grade castor oil, and food-grade castor oil.

[0016] Furthermore, the modified castor oil refers to the modified castor oil obtained by chemically modifying castor oil, and the hydroxyl value thereof is 180 to 220 KOH / g.

[0017] Furthermore, the modified castor oil includes one or more of epoxidized modified castor oil, hydrogenated modified castor oil, and acylated modified castor oil.

[0018] Preferably, the amount of castor oil polyol is 50 to 60 parts.

[0019] Preferably, the molecular weight of the polyether polyol is 400 to 1000. Polyether polyols in this molecular weight range are effectively combined with castor oil and reactive plasticizers, thereby facilitating the optimization of overall performance.

[0020] Furthermore, the polyether polyol is polyoxypropylene polyether polyol.

[0021] Furthermore, the polyoxypropylene polyether polyol includes one or more of polyoxypropylene diol and / or polyoxypropylene triol.

[0022] Preferably, the polyether polyol accounts for 20 to 30 parts.

[0023] Furthermore, the reactive plasticizer is a plasticizer containing an active group, which can chemically react with the polymer polyol under certain conditions, so that the two are connected by forming a chemical bond.

[0024] Furthermore, the reactive plasticizer is benzoic acid and / or versatic acid maleate.

[0025] Preferably, the reactive plasticizer is benzoic acid. The active group phenolic hydroxyl contained in benzoic acid can form a chemical bond with the polymer, so it is not easy to precipitate from the polymer matrix, thereby showing better durability and stability.

[0026] The present invention protects a two-component polyurethane potting adhesive, comprising component A and component B;

[0027] Wherein, the component A comprises, by weight: the above resin composition, 0.2-0.3 parts of defoaming agent, and 0.05-0.1 parts of catalyst;

[0028] The B component includes: 40-60 parts of isocyanate, 20-30 parts of flame retardant, and 20-30 parts of non-reactive plasticizer;

[0029] The two-component polyurethane potting adhesive does not contain fillers.

[0030] Component A and component B together constitute a high-performance two-component polyurethane potting glue, each playing an indispensable role. As the main body of the potting glue, component A provides the necessary physical and chemical properties, improves fluidity and filling properties, and ensures the potting effect; at the same time, the catalyst in component A, after mixing with component B, can accelerate the overall curing process, improve production efficiency, and form a protective layer after curing, effectively preventing electronic components from being affected by the external environment. Component B mainly plays a curing role, generating polyurethane through the reaction of isocyanate with the polymer polyol in component A, significantly improving the strength, hardness and heat resistance of the potting glue. In addition, the flame retardant in component B significantly improves the flame retardant properties of the potting glue, making it safer and more reliable; and the optimized selection of plasticizers further improves the flexibility and processing properties of the potting glue. Therefore, this two-component polyurethane potting glue has excellent weather resistance, mechanical properties, flame retardancy and processing properties through the synergistic effect of components A and B, and can meet the needs of various complex application scenarios.

[0031] Furthermore, the defoaming agent is a silicone defoaming agent and / or a non-silicon defoaming agent.

[0032] Furthermore, the defoaming agent includes one or more of BYK-088, BYK-A500, BYK-A535, BYK-A550, and BYK-A555.

[0033] Furthermore, the catalyst includes one or more of an organic tin catalyst, an organic bismuth catalyst, an organic zinc catalyst, and an organic amine catalyst.

[0034] Furthermore, the catalyst is an organotin catalyst, because it has excellent comprehensive performance and relatively low cost.

[0035] Preferably, the organotin catalyst includes one or more of dibutyltin dilaurate, dimethyltin dilaurate, and dibutyltin diacetate.

[0036] Furthermore, the isocyanate includes one or more of 2,4-toluene diisocyanate, a 2,4-diphenylmethane diisocyanate mixture, and 4,4-diphenylmethane diisocyanate.

[0037] Furthermore, the flame retardant is an aliphatic phosphate flame retardant and / or an aromatic phosphate flame retardant.

[0038] Furthermore, the flame retardant is an aliphatic phosphate flame retardant.

[0039] Preferably, the aliphatic phosphate flame retardant includes one or more of triethyl phosphate, tricresyl phosphate, and tolylene diphenyl phosphate.

[0040] Furthermore, the non-reactive plasticizer is a plasticizer without active groups, which is mainly dispersed in the resin or polymer by physical means, and is combined with each other by physical effects such as van der Waals forces, and will not change the chemical structure of the resin or polymer.

[0041] Furthermore, the non-reactive plasticizer includes one or more of dioctyl adipate, epoxy soybean oil, diisononyl cyclohexane-1,2-dicarboxylate (DINCH), and naphthenic oil.

[0042] The present invention provides a method for preparing the above-mentioned two-component polyurethane potting adhesive, comprising the following steps:

[0043] S1. The dehydrated resin composition obtained above, the defoamer and the catalyst are mixed to obtain a mixture of component A;

[0044] S2. The dehydrated non-reactive plasticizer and flame retardant are mixed with isocyanate to obtain a mixture of component B;

[0045] S3. The component A mixture obtained in step S1 and the component B mixture obtained in step S2 are mixed and degassed, and then cured at room temperature to obtain a two-component polyurethane potting adhesive.

[0046] The present invention first prepares a mixture of component A and a mixture of component B respectively, mixes the two, and undergoes vacuum dehydration and curing treatment to successfully prepare a two-component polyurethane potting glue with excellent performance. The potting glue has the following significant characteristics: high weather resistance, able to maintain stable performance in a variety of harsh environments; excellent mechanical properties, able to withstand large external forces and pressures without being easily damaged; high transparency, easy to observe the operating status of internal components; at the same time, it also has good defoaming properties, ensuring the flatness and aesthetics of the potting glue.

[0047] Furthermore, in step S1, the temperature of the dehydration treatment is 100-120°C.

[0048] Furthermore, in step S1, the dehydration treatment time is 2 to 3 hours.

[0049] Furthermore, in step S1, the mixing is stirring mixing.

[0050] Furthermore, the stirring and mixing condition is stirring at 300 rpm / min for 10 to 20 min.

[0051] Furthermore, in step S2, the temperature of the dehydration treatment is 100-120°C.

[0052] Furthermore, in step S2, the dehydration treatment time is 1 to 2 hours.

[0053] Furthermore, in step S3, the mass ratio of the component A mixture to the component B mixture is 1:(0.8-1.2).

[0054] Furthermore, in step S3, the curing time is 24 to 48 hours.

[0055] The present invention protects the application of the two-component polyurethane potting adhesive in the field of electrical appliance potting adhesive.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The present invention uses a reactive plasticizer, castor oil and polyether polyol to prepare a resin composition with a synergistic effect, and further mixes it with a curing component to prepare a two-component polyurethane potting glue. The resin composition significantly enhances the weather resistance, mechanical properties, transparency and defoaming properties of the potting glue. Among them, the presence of castor oil makes the potting glue show an excellent yellowing resistance effect; the polyether polyol improves the overall strength and stability of the potting glue; the reactive plasticizer effectively prevents the precipitation of the plasticizer under low and high temperature, hot and humid conditions, and exposure to the sun due to its chemical bonding with the polyurethane chain segment. Based on the resin composition of a specific composition, the present invention prepares a two-component polyurethane potting glue with excellent weather resistance, mechanical properties, transparency and defoaming properties, which broadens its application under extreme environmental conditions. DETAILED DESCRIPTION

[0058] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0059] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0060] Castor oil (hydroxyl value 155-170KOH / g): purchased from Fucheng County Huanyu Oil Co., Ltd.;

[0061] Polyether polyol (molecular weight 400), polyether polyol (molecular weight 1000): purchased from Wanhua Chemical;

[0062] Reactive plasticizer: Benzoic acid plasticizer PB-10 was purchased from Xiamen Juyou Company;

[0063] Non-reactive plasticizers: dioctyl adipate (DOA) and diisononyl cyclohexane-1,2-dicarboxylate (DINCH) were purchased from Foshan Jinjia New Material Technology Co., Ltd.; Epoxidized soybean oil was purchased from Guangzhou Haierma Vegetable Oil Co., Ltd.; 4010 naphthenic oil was purchased from Hengshui Diyi Petrochemical Co., Ltd.;

[0064] Catalyst: Dibutyltin dilaurate was purchased from Guangzhou Haoyi New Materials Technology Co., Ltd.;

[0065] Defoaming agent: BYK088 was purchased from BYK Additives (Shanghai) Co., Ltd.;

[0066] Isocyanate: 4,4-diphenylmethane diisocyanate was purchased from Wanhua Chemical;

[0067] Flame retardant: Triethyl phosphate (TEP) was purchased from Shandong Ruixing Flame Retardant Technology Co., Ltd.

[0068] Embodiments 1 to 4: A two-component polyurethane potting adhesive

[0069] This embodiment provides a two-component polyurethane potting adhesive, which is prepared according to the formula in Table 1 and a preparation method comprising the following steps:

[0070] S1. The components of component A were mixed in a high-speed machine and stirred at 300 rpm / min for 15 min until uniform, followed by vacuum dehydration at 120 ° C for 3 h to obtain a mixture of component A;

[0071] S2. 40 parts of dioctyl adipate (DOA) and 30 parts of triethyl phosphate (TEP) in component B were heated to 120°C for vacuum dehydration for 2h, then cooled to 60°C, and then 30 parts of 4,4-diphenylmethane diisocyanate were added and mixed uniformly to obtain a mixture of component B;

[0072] S3. The component A mixture obtained in step S1 and the component B mixture obtained in step S2 are uniformly mixed in a mass ratio of 1:1, and then cured at room temperature for 48 hours to obtain a two-component polyurethane potting adhesive.

[0073] Comparative Examples 1 to 7: One-component / two-component polyurethane potting glue

[0074] The weight parts of the raw materials used in the following comparative examples are shown in Table 2.

[0075] Comparative Example 1 provides a two-component polyurethane potting adhesive, which is prepared by referring to the method of Example 1. The difference from Example 1 is that no polyether polyol (molecular weight 1000) is added, the amount of castor oil added is 70 parts, and other raw materials, steps and parameters are the same as those of Example 1.

[0076] Comparative Example 2 provides a two-component polyurethane potting adhesive, which is prepared by referring to the method of Example 1. The difference from Example 1 is that castor oil is not added, the addition amount of polyether polyol (molecular weight 1000) is 70 parts, and other raw materials, steps and parameters are the same as those in Example 1.

[0077] Comparative Example 3 provides a two-component polyurethane potting adhesive, which is prepared by referring to the method of Example 1. The difference from Example 1 is that PB-10 is replaced by an equal amount (29.7 parts) of DOA, and other raw materials, steps and parameters are the same as those in Example 1.

[0078] Comparative Example 4 provides a two-component polyurethane potting adhesive, which is prepared by referring to the method of Example 1. The difference from Example 1 is that PB-10 is replaced by an equal amount (29.7 parts) of diisononyl cyclohexane-1,2-dicarboxylate (DINCH), and other raw materials, steps and parameters are the same as those in Example 1.

[0079] Comparative Example 5 provides a two-component polyurethane potting adhesive, which is prepared by referring to the method of Example 1. The difference from Example 1 is that PB-10 is replaced by an equal amount (29.7 parts) of epoxidized soybean oil, and other raw materials, steps and parameters are the same as those in Example 1.

[0080] Comparative Example 6 provides a two-component polyurethane potting adhesive, which is prepared by referring to the method of Example 1. The difference from Example 1 is that PB-10 is replaced by an equal amount (29.7 parts) of 4010 cyclopentane oil, and other raw materials, steps and parameters are the same as those in Example 1.

[0081] Comparative Example 7 provides a two-component polyurethane potting adhesive, which is prepared by referring to the method of Example 1. The difference from Example 3 is that the polyether polyol (molecular weight 400) is replaced by an equal amount (20 parts) of polyester polyol (molecular weight 400), and the other raw materials, steps and parameters are the same as those in Example 1.

[0082] Table 1 Weight parts of raw materials used in Examples 1 to 4

[0083]

[0084] Table 2 Weight parts of raw materials used in Comparative Examples 1 to 7

[0085]

[0086]

[0087] Experimental example: Mechanical properties, weather resistance and appearance properties of polyurethane potting glue

[0088] 1. Experimental Methods

[0089] (1) Appearance test: A mixture of component A and a mixture of component B in a mass ratio of 1:1 were stirred to obtain 50 g of glue, and then the glue was poured into a 100 mL plastic cup and subjected to vacuum degassing treatment. Finally, the appearance of the glue after curing was observed.

[0090] (2) Hardness test: The potting glue obtained in the above-mentioned embodiments and comparative examples was tested using a hardness tester according to the national standard GB / T531.2-2009 of the People's Republic of China.

[0091] (3) Defoaming test: A mixture of component A and component B in a mass ratio of 1:1 was stirred to obtain 50 g of glue, which was then poured into a 100 mL plastic cup. The internal bubbles after curing were observed.

[0092] (4) Tensile strength test: According to the national standard GB / T2568-1995 of the People's Republic of China, the potting glue obtained in the above embodiments and comparative examples was cured in a mold of 200*20*4 mm, and then the tensile strength was tested.

[0093] (5) Double 85 test: The potting glue obtained in the above embodiments and comparative examples was placed in a constant temperature box at 85°C and relative humidity of 85%, set up a sensor test device, and left to stand for 1000 hours to observe the changes in appearance.

[0094] (6) Outdoor irradiation test: The potting adhesives obtained in the above embodiments and comparative examples were placed in an area directly exposed to sunlight for 1000 hours, and the changes in appearance were observed.

[0095] (7) Low temperature test: The potting glue obtained in the above embodiments and comparative examples was placed in a constant temperature box at 5°C and relative humidity of 60%, and a sensor test device was set up. It was left to stand for 1000 hours and the appearance changes were observed.

[0096] 2. Experimental results

[0097] Table 3 Mechanical properties, weather resistance and appearance performance test of polyurethane potting glue

[0098]

[0099]

[0100] As shown in Table 3, the results of Example 1 and Comparative Example 1 show that when only castor oil is used as the polyol component without adding polyether polyol (molecular weight 1000), the colloid color is affected by the resin and presents a dark yellow color, which affects the transparency; and the hardness is significantly reduced, and the mechanical properties are impaired.

[0101] The results of Example 1 and Comparative Example 2 show that when only polyether polyol (molecular weight 1000) is used without adding castor oil, the use of a large amount of polyether polyol seriously affects the defoaming property, resulting in an excessive number of bubbles, affecting the appearance, reducing the hardness and destroying the sealing property; plasticizer exudation occurs in the double 85 test, outdoor irradiation test, and low temperature test, and the weather resistance is impaired.

[0102] The results of Example 1 and Comparative Examples 3 to 6 all show that when a non-reactive plasticizer (any one of DOA, DINCH, epoxidized soybean oil, and 4010 cyclohexane oil) is used instead of the reactive plasticizer PB-10, the plasticizer is free in the resin system and cannot be connected to the polyurethane chain segment, causing a significant decrease in tensile strength and hardness, and impairing the mechanical properties; among them, DINCH and 4010 cyclohexane oil also cause the plasticizer to precipitate, and the weather resistance is seriously impaired; epoxidized soybean oil also causes the colloid color to change and severe yellowing after the double 85 test.

[0103] The results of Example 3 and Comparative Example 7 show that when polyester polyol (molecular weight 400) is used instead of polyether polyol (molecular weight 400), the defoaming property is seriously affected, resulting in impaired appearance and sealing performance.

[0104] In summary, in the two-component polyurethane potting glue of the present invention, castor oil, polyether polyol and reactive plasticizer play a significant synergistic role, which not only significantly enhances the weather resistance of the potting glue, but also achieves excellent stability; at the same time, it performs well in terms of hardness (>35), tensile strength (>0.35), etc., and greatly improves the mechanical properties of the potting glue; in addition, the combination of the above ingredients also ensures that the potting glue has relatively excellent transparency and defoaming properties (bubble diameter <1mm, number of bubbles <50), and successfully prepares a two-component polyurethane potting glue with high weather resistance, excellent mechanical properties, high transparency and good defoaming properties.

[0105] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A resin composition, characterized in that The raw materials include the following by weight: 70 to 90 parts of polymer polyol and 15 to 30 parts of reactive plasticizer; Wherein, the polymer polyol comprises at least castor oil and polyether polyol; The reactive plasticizer is a plasticizer having a hydroxyl group.

2. The resin composition according to claim 1, characterized in that: The reactive plasticizer is benzoic acid and / or versatic acid maleate.

3. The resin composition according to claim 1, characterized in that: The castor oil is non-modified castor oil and / or modified castor oil.

4. The resin composition according to claim 1, characterized in that: The polyether polyol is polyoxypropylene polyether polyol.

5. A two-component polyurethane potting adhesive, characterized in that: It includes component A and component B; Wherein, the component A comprises, by weight: the resin composition according to any one of claims 1 to 4, 0.2 to 0.3 parts of a defoaming agent, and 0.05 to 0.1 parts of a catalyst; The B component includes: 40-60 parts of isocyanate, 20-30 parts of flame retardant, and 20-30 parts of non-reactive plasticizer; The two-component polyurethane potting adhesive does not contain fillers.

6. The two-component polyurethane potting adhesive according to claim 5, characterized in that: The isocyanate includes one or more of 2,4-methyl diisocyanate, 2,4-diphenylmethane diisocyanate, and 4,4-diphenylmethane diisocyanate.

7. The two-component polyurethane potting adhesive according to claim 5, characterized in that: The flame retardant is an aliphatic phosphate flame retardant and / or an aromatic phosphate flame retardant.

8. The two-component polyurethane potting adhesive according to claim 5, characterized in that: The non-reactive plasticizer includes one or more of dioctyl adipate, epoxy soybean oil, diisononyl cyclohexane-1,2-dicarboxylate, and naphthenic oil.

9. The method for preparing the two-component polyurethane potting adhesive according to any one of claims 5 to 8, characterized in that: The following steps are involved: S1. The dehydrated resin composition according to any one of claims 1 to 4, the defoamer and the catalyst are mixed to obtain a mixture of component A; S2. The dehydrated non-reactive plasticizer and flame retardant are mixed with isocyanate to obtain a mixture of component B; S3. The component A mixture obtained in step S1 and the component B mixture obtained in step S2 are mixed and degassed, and then cured at room temperature to obtain a two-component polyurethane potting adhesive.

10. Use of the resin composition according to any one of claims 1 to 4 or the two-component polyurethane potting adhesive according to any one of claims 5 to 8 in the preparation of electrical appliance coating adhesive.

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