Addition type pouring sealant prime coat liquid as well as preparation method and application thereof

Abstract

The invention relates to the technical field of organosilicone addition type heat-conducting flame-retardant pouring sealants, and particularly discloses an addition type pouring sealant base coating liquid as well as a preparation method and application thereof. The addition type pouring sealant primer comprises the following components in parts by weight: 50-70 parts of a tackifier, 0.5-4 parts of a cross-linking agent, 0.001-0.1 part of a catalyst and 30-50 parts of a solvent, the tackifier is a functional titanate tackifier modified by titanate; the titanate modified functional type titanate tackifier is prepared from trimethylolpropane diallyl ether, ethyl acetoacetate and mono-alkoxy type titanate through an ester exchange reaction. The addition type pouring sealant disclosed by the invention can be used for improving the adhesion of each component in the driving power supply, preventing water vapor or moisture in the air from easily permeating into an electronic device through a combined surface of a material and a glue layer, and being beneficial to improving the waterproof and moistureproof performance of the LED driving power supply when the LED driving power supply is used outdoors.

Description

Technical Field

[0001] The invention relates to the technical field of organic silicon addition-type heat-conductive flame-retardant potting adhesive, and in particular to an addition-type potting adhesive primer liquid and a preparation method and application thereof. Background Art

[0002] Silicone addition thermally conductive flame retardant potting adhesive has good resistance to high and low temperatures, ozone and weathering. No by-products are produced during the vulcanization process, and the shrinkage rate is low. After curing, the product has stable electrical and chemical properties and excellent moisture resistance. It is widely used in lamps, electrical appliances, new energy and other fields.

[0003] In recent years, with the rapid development and promotion of the LED industry, addition-type silicone thermal conductive flame retardant potting glue has become the mainstream glue product for internal potting of LED driver power supplies. However, after the curing of the silicone addition potting glue, most of the product surface is non-polar groups, with low surface energy, poor adhesion to the materials in the driver power supply, and the glue layer and the substrate (such as aluminum shell materials, PET insulation sheets, PVC insulation tapes, PCB boards, etc.) are easy to peel off. Water vapor or moisture in the air can easily penetrate into the interior of electronic devices through the joint surface between the material and the glue layer, affecting the insulation and corrosion resistance of the product. In particular, when the LED driver power supply is used outdoors, more stringent waterproof and moisture-proof properties are required, and the potting glue has good adhesion to various types of devices inside the power supply. In order to improve the adhesion between the addition type potting glue and the internal components of the LED driver power supply, one method is to directly mix the tackifier into the potting glue. However, the potting glue adhesion improvement effect is not obvious and the cost is high. Most tackifiers contain amino compounds, which can easily inhibit the catalytic activity of Pt in the potting glue and affect the curing effect of the addition type potting glue. Another method is to use a primer to assist in improving the adhesion between the potting glue and the substrate. This method is currently the most effective and economical method. Summary of the invention

[0004] In view of the above-mentioned shortcomings that currently exist, the present invention provides an addition-type potting glue primer and its preparation method and application. The present invention configures and invents a new addition-type potting glue primer to assist the addition-type potting glue in bonding the internal device substrate of the LED driver power supply. The prepared primer has good coating properties and a moderate drying time. After drying, it forms a uniform coating film on the surface of the substrate bonded to the internal power supply of the LED. It is compatible with the addition-type potting glue, does not cause poisoning, and assists the potting glue in maintaining good adhesion with the internal device substrate of the power supply. The addition-type potting glue of the present invention can prevent water vapor or moisture in the air from easily penetrating into the interior of the electronic device through the bonding surface of the material and the glue layer, which is beneficial to improving the waterproof and moisture-proof performance of the LED driver power supply when used outdoors.

[0005] In order to achieve the above object, the present invention provides an addition type potting glue primer, which comprises, by weight: 50-70 parts of a tackifier, 0.5-4 parts of a cross-linking agent, 0.001-0.1 parts of a catalyst, and 30-50 parts of a solvent;

[0006] The tackifier is a titanate-modified functional titanate tackifier;

[0007] The titanate-modified functional titanate tackifier is prepared by ester exchange reaction of trimethylolpropane diallyl ether, ethyl acetoacetate and monoalkoxy titanate.

[0008] According to one aspect of the present invention, the method for preparing the titanate-modified functional titanate tackifier comprises the following steps:

[0009] Put the monoalkoxy titanate into a reaction kettle, introduce nitrogen for protection, and start stirring; heat up to 60-70°C, slowly add trimethylolpropane diallyl ether dropwise, and control the addition to be completed within 2-3 hours; heat up to 80-85°C, keep the temperature for reaction for 3 hours, vacuumize and distill under reduced pressure, control the air pressure below -0.09MPa, heat up to 85-120°C, and distill the excess alcohol substances and other by-products of the titanate ester exchange; 0.5h after the reaction is completed, introduce nitrogen again, cool down to 60-70°C, slowly add dropwise to ethyl acetoacetate, and control the addition to be completed within 1.5-2h; heat up to 80-85°C, react for 2h, vacuumize and distill under reduced pressure, control the air pressure below -0.09MPa, heat up to 85-120°C, and distill the excess alcohol substances and other by-products; after nitrogen is introduced and cooled to room temperature, add solvent, and seal for storage.

[0010] Preferably, the inert atmosphere includes any one of nitrogen and argon.

[0011] According to one aspect of the present invention, the monoalkoxy titanate includes one or two of tetraisopropyl titanate and tetraisobutyl titanate; the effective content of trimethylolpropane diallyl ether is greater than 98%; and the effective content of ethyl acetoacetate is greater than 98%.

[0012] According to one aspect of the present invention, the cross-linking agent is polymethylsiloxane, and the viscosity of the polymethylsiloxane at 25° C. is 10-100 CP.

[0013] According to one aspect of the present invention, the catalyst is a Pt catalyst.

[0014] According to one aspect of the present invention, the solvent includes at least one of toluene, xylene and petroleum ether.

[0015] Based on the same inventive concept, the present invention also provides a method for preparing the above-mentioned addition-type potting glue primer, comprising the following steps:

[0016] Under inert atmosphere, the tackifier is stirred, refluxed, and heated to 40°C; a catalyst is added, and then a cross-linking agent is slowly added, and the temperature is raised to 60-70°C, reacted for 1 hour, and then cooled to room temperature; a solvent is added, stirred evenly, and the material is discharged to obtain an addition-type potting adhesive primer liquid.

[0017] Preferably, the inert atmosphere includes any one of nitrogen and argon.

[0018] Based on the same inventive concept, the present invention also provides the use of the above-mentioned addition-type potting glue primer liquid or the addition-type potting glue primer liquid prepared by the above-mentioned preparation method in the internal potting of an LED driving power supply.

[0019] Beneficial effects of the present invention:

[0020] (1) The present invention uses trimethylolpropane diallyl ether, ethyl acetoacetate, and titanate as main raw materials, introduces functional group ether bonds and ester bonds into titanate through an ester exchange reaction, and synthesizes a titanate functional tackifier after the reaction. The tackifier molecular structure contains not only ester groups but also double ether bond groups, which cooperate with each other and have high polarity. The prepared primer has good air drying properties and can improve the surface polarity of the bonding substrate during application. At the same time, the reactive group ethylene bond introduced into the tackifier is added with a cross-linking agent polymethylsiloxane, a Pt catalyst, and a solvent to prepare a new addition-type potting glue primer under certain conditions.

[0021] (2) The addition type potting adhesive primer of the present invention uses trimethylolpropane diallyl ether, ethyl acetoacetate, and titanate as main raw materials, firstly synthesizes a functional tackifier through ester exchange reaction, and then adds a certain amount of cross-linking agent, catalyst, etc. The addition type primer prepared under certain conditions can solve the problem of poor adhesion or debonding between the internal device substrate of the LED driving power supply and the addition type potting adhesive, and has excellent adhesion with the aluminum shell of the LED power supply, PCB board, PET insulating sheet, and PVC insulating tape, and will not debond or corrode after 1000 hours in a double 85 high temperature and high humidity environment.

[0022] (3) The addition type potting glue primer of the present invention improves the adhesion of the addition type potting glue to the internal components of the driver power supply (such as aluminum housing, PET insulating sheet, PVC insulating tape, PCB board, etc.), preventing water vapor or moisture in the air from easily penetrating into the interior of the electronic device through the joint surface between the material and the adhesive layer, which is beneficial to improving the waterproof and moisture-proof performance of the LED driver power supply when used outdoors. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1Adhesion between the addition type potting adhesive primer prepared in Example 1 of the present invention and the substrate after aging for 1000 hours at 85% RH and 85°C; (a) the substrate is housing aluminum; (b) the substrate is PET insulating sheet; (c) the substrate is PVC insulating tape; (d) the substrate is PCB board;

[0024] Figure 2 The bonding conditions between the addition type potting glue primer prepared in comparative example 1 of the present invention and the substrate; (a) the substrate is housing aluminum; (b) the substrate is PET insulating sheet; (c) the substrate is PVC insulating tape; (d) the substrate is PCB board. DETAILED DESCRIPTION

[0025] To make the present invention easier to understand, the present invention is further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the professional terms used below are consistent with the meanings understood by professional and technical personnel in the field; unless otherwise specified, the raw materials and reagents involved in this article can be purchased from the market or prepared by known methods.

[0026] Example 1

[0027] An addition type potting glue primer and its preparation method:

[0028] An addition type potting glue primer liquid comprises the following raw materials in parts by weight:

[0029] Titanate modified functional titanate thickener: 60 parts

[0030] Polymethylsiloxane: 1.5 parts (50CP, 25°C)

[0031] Pt catalyst: 0.02 parts

[0032] Xylene: 40 parts

[0033] The method for preparing the titanate-modified functional titanate tackifier comprises the following steps:

[0034] Take 100 parts of tetraisopropyl titanate and put them into the reaction kettle, pass nitrogen for protection, start stirring, heat to 65°C, slowly add 80 parts of trimethylolpropane diallyl ether dropwise, control the addition within 2 hours, heat to 85°C, keep warm for reaction for 3 hours, vacuum and reduce pressure distillation, control the air pressure below -0.09MPa, heat to 110°C, react for 0.5h, pass nitrogen again, cool to 65°C, slowly add 50 parts of ethyl acetoacetate dropwise, control the addition within 1.5h, heat to 85°C, react for 2h, vacuum and reduce pressure distillation, control the air pressure below -0.09MPa, heat to 90°C, wait for distillation to be completed, pass nitrogen to cool to room temperature, after completion, add 40 parts of xylene, stir evenly, and seal for storage.

[0035] A method for preparing an addition-type potting adhesive primer liquid comprises the following steps:

[0036] Take 60 parts of the above homemade tackifier, pass nitrogen protection, start stirring, reflux, heat to 40°C, add 0.02 parts of Pt catalyst, and then slowly add 1.5 parts of polymethylsiloxane. After completion, heat to 60°C, react for 1 hour, cool to room temperature, add 45 parts of xylene, stir evenly, discharge, and prepare the above primer.

[0037] Example 2

[0038] An addition type potting glue primer and its preparation method:

[0039] An addition type potting glue primer liquid comprises the following raw materials in parts by weight:

[0040] Titanate modified functional titanate thickener: 55 parts

[0041] Polymethylsiloxane: 2 parts (50CP, 25℃)

[0042] Pt catalyst: 0.02 parts

[0043] Xylene: 45 parts

[0044] The method for preparing the titanate-modified functional titanate tackifier comprises the following steps:

[0045] Put 100 parts of tetrabutyl titanate into a reaction kettle, pass nitrogen for protection, start stirring, heat to 65°C, slowly add 75 parts of trimethylolpropane diallyl ether dropwise, control the addition to be completed within 2 hours, heat to 85°C, keep warm for reaction for 3 hours, vacuum distill under reduced pressure, control the air pressure below -0.09MPa, heat to 110°C, react for 0.5h, pass nitrogen again, cool to 65°C, slowly add 55 parts of ethyl acetoacetate dropwise, control the addition to be completed within 1.5h, heat to 85°C, react for 2h, vacuum distill under reduced pressure, control the air pressure below -0.09MPa, heat to 100°C, wait for distillation to be completed, pass nitrogen to cool to room temperature, after completion, add 50 parts of xylene, stir evenly, and seal for storage.

[0046] A method for preparing an addition-type potting adhesive primer liquid comprises the following steps:

[0047] Take 55 parts of the homemade tackifier above, pass nitrogen protection, start stirring, reflux, heat to 40°C, add 0.02 parts of Pt catalyst, and then slowly add 2 parts of polymethylsiloxane. After completion, heat to 60°C, react for 1 hour, cool to room temperature, add 45 parts of xylene, stir evenly, discharge, and prepare the above-mentioned primer.

[0048] Comparative Example 1

[0049] Take 100 parts of tetraisopropyl titanate and put them into the reaction kettle, pass nitrogen for protection, start stirring, heat to 65°C, slowly add 50 parts of ethyl acetoacetate dropwise, control the addition within 1.5 hours, heat to 85°C, react for 2 hours, vacuum distill under reduced pressure, control the air pressure below -0.09MPa, heat to 90°C, wait for the distillation to be completed, pass nitrogen and lower to room temperature, after completion, add 75 parts of trimethylolpropane diallyl ether and 40 parts of xylene, stir evenly, and seal for storage.

[0050] The other components and preparation methods are the same as those in Example 1.

[0051] Comparative Example 2

[0052] The components and preparation method are the same as those in Example 1, except that trimethylolpropane diallyl ether is not present in the entire preparation process.

[0053] Comparative Example 3

[0054] Take 100 parts of tetraisopropyl titanate and put them into the reaction kettle, pass nitrogen for protection, start stirring, heat to 65°C, slowly add 80 parts of trimethylolpropane diallyl ether, control the addition to be completed within 2 hours, heat to 85°C, keep warm for reaction for 3 hours, vacuum distill under reduced pressure, control the air pressure below -0.09 MPa, heat to 110°C, react for 0.5 hours, pass nitrogen again, pass nitrogen down to room temperature, after completion, add 55 parts of ethyl acetoacetate and 40 parts of xylene, stir evenly, and seal for storage.

[0055] Comparative Example 4

[0056] Without any primer assistance, a blank control of the well-known brand LED power supply additive potting glue on the market was used.

[0057] Performance testing and result analysis

[0058] The drying time and adhesion of the addition type primer solutions provided in Examples 1 to 2 and Comparative Examples 1 to 4 were tested.

[0059] Test process: The test was conducted using a well-known brand of LED power supply plus potting glue, among which some technical parameters of the product are as follows. (Thermal conductivity 0.9W / m·K; Mixing mass ratio: 1:1; Viscosity after mixing: 3000CP-4500CP; Curing time: Operation time 30-40min, complete curing in 24h; Under 25℃, tensile strength: 0.6Mpa, elongation: 50%.)

[0060] Test items:

[0061] Drying time: visually inspected, under the conditions of 23±2℃, 50±5%RH, the prepared primer solution was applied to the surface of the bonding substrate by spraying. A uniform coating film could be formed on the surface of the substrate within 24 hours after drying, and the time was recorded.

[0062] Adhesion test with substrate: GB / T 16776-2005 Appendix D 1.2 Hand pull test method;

[0063] ○Print: organic silica gel fracture (agglutination destruction rate 50%-100%);

[0064] △Print: There is some interface peeling between the organic silica gel layer and the substrate (cohesion failure rate 1% to 50%);

[0065] ×: No adhesion (agglutination destruction rate 0%).

[0066] Double 85 high temperature and high humidity environment: storage conditions 85% RH, 85℃, 1000h.

[0067] The above test results are shown in Table 1 below:

[0068] Table 1 Comprehensive performance test results of Examples 1 to 2 and Comparative Examples 1 to 4

[0069]

[0070] From the results of Examples 1-2 in Table 1, it can be seen that the drying time of the addition type primer prepared by the functional tackifier synthesized by ester exchange reaction with trimethylolpropane diallyl ether, ethyl acetoacetate, and titanate as the main raw materials is 5min and 7min respectively; when spraying LED housing aluminum, PET insulating sheet, PVC insulating tape, and PCB board, the addition type potting glue shows good adhesion to each substrate. This is because the functional additive in the prepared primer introduces ether bonds and polar group ester groups, which has good compatibility with the product substrate and improves the adhesion to the substrate; at the same time, under double 85 conditions, after aging for 1000h, the addition type potting glue still maintains stable adhesion, as shown in the following example. Figure 1 As shown, by Figure 1 It can be seen that under the double 85 condition, after aging for 1000 hours, the addition-type potting glue has no corrosion phenomenon. This is because the synthesized functional tackifier also contains vinyl double bonds. In the process of preparing the primer, under the action of Pt catalyst, the cross-linking agent polymethylsiloxane will undergo addition reaction with the silicon-hydrogen bond. The prepared compound contains active group Si-H bond, which will undergo addition cross-linking reaction with the vinyl silicone oil in the potting glue to form a stable cross-linked network structure.

[0071] It can also be seen from the results in Table 1 that in the process of preparing the primer, when trimethylolpropane diallyl ether does not directly participate in the reaction or is not added to the raw materials, compared with the results of Example 1, the drying time of Comparative Example 1 is 360 minutes, and Comparative Example 2 is still an oily liquid after 24 hours of drying. When spraying LED housing aluminum, PET insulating sheet, PVC insulating tape, and PCB board substrate, the additive potting glue of Comparative Examples 1, 2 and the blank sample Comparative Example 4 debonds with each substrate in blocks without any colloid residue, such as Figure 2 As shown, it is shown that trimethylolpropane diallyl ether has good air-drying property when participating in the transesterification reaction of titanate, which can shorten the drying time of the primer, and at the same time, can improve the bonding effect of the functional titanate tackifier on each substrate. When ethyl acetoacetate in comparative example 3 does not participate in the transesterification reaction of the functional titanate tackifier, it is directly added to the primer, and the drying time after the primer is sprayed is 8 minutes. The potting glue has a certain adhesion to each substrate LED housing aluminum, PET insulating sheet, PVC insulating tape, and PCB board. However, the bonding effect is still different from the results of Example 1. It shows that ethyl acetoacetate does not participate in the transesterification reaction, and the synergistic effect of bonding with each substrate will be reduced. This is because ethyl acetoacetate is volatile and easily hydrolyzed, and the ester group of the polar group of the primer is deactivated and ineffective, which directly affects the adhesion of the potting glue to the substrate.

[0072] Therefore, in summary, functional group ether bonds and ester bonds are introduced into titanate through ester exchange reaction, and a titanate functional tackifier is synthesized after the reaction. The molecular structure of the tackifier contains not only ester groups, but also double ether bond groups, which cooperate with each other and have high polarity. The surface polarity of the bonding substrate can be improved during the application process. The prepared primer has good air-drying properties and auxiliary bonding effects. When sprayed on LED power supply housing aluminum, PCB board, PET insulating sheet, and PVC insulating glue, the addition-type potting glue has excellent adhesion to each substrate, and will not debond or corrode after 1000 hours in a double 85 high temperature and high humidity environment.

[0073] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the art within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An addition type potting glue primer, characterized in that: According to weight parts, it includes: 50-70 parts of tackifier, 0.5-4 parts of cross-linking agent, 0.001-0.1 parts of catalyst, and 30-50 parts of solvent; The tackifier is a titanate-modified functional titanate tackifier; The titanate-modified functional titanate tackifier is prepared by ester exchange reaction of trimethylolpropane diallyl ether, ethyl acetoacetate and monoalkoxy titanate.

2. The addition type potting glue primer according to claim 1, characterized in that: The preparation method of the titanate-modified functional titanate tackifier comprises the following steps: Put the monoalkoxy titanate into a reaction kettle, introduce nitrogen for protection, and start stirring; heat up to 60-70°C, slowly add trimethylolpropane diallyl ether dropwise, and control the addition to be completed within 2-3 hours; heat up to 80-85°C, keep warm for reaction for 3 hours, vacuumize and distill under reduced pressure, control the air pressure below -0.09MPa, heat up to 85-120°C, and distill the excess alcohol substances and other by-products of titanate ester exchange; 0.5h after the reaction is completed, introduce nitrogen again, cool down to 60-70°C, slowly add dropwise to ethyl acetoacetate, and control the addition to be completed within 1.5-2h; heat up to 80-85°C, react for 2h, vacuumize and distill under reduced pressure, control the air pressure below -0.09MPa, heat up to 85-120°C, and distill the excess alcohol substances and other by-products; after nitrogen is introduced and cooled to room temperature, add solvent, and seal for storage.

3. The addition type potting glue primer according to claim 1, characterized in that: The monoalkoxy titanate includes one or two of tetraisopropyl titanate and tetraisobutyl titanate; the effective content of trimethylolpropane diallyl ether is greater than 98%; and the effective content of ethyl acetoacetate is greater than 98%.

4. The addition type potting glue primer according to claim 1, characterized in that: The cross-linking agent is polymethylsiloxane, and the viscosity of the polymethylsiloxane at 25° C. is 10-100 CP.

5. The addition type potting glue primer according to claim 1, characterized in that: The catalyst is a Pt catalyst.

6. The addition type potting glue primer according to claim 1, characterized in that: The solvent includes at least one of toluene, xylene and petroleum ether.

7. The method for preparing the addition type potting glue primer according to any one of claims 1 to 6, characterized in that: The following steps are involved: Under inert atmosphere, the tackifier is stirred, refluxed, and heated to 40°C; a catalyst is added, and then a cross-linking agent is slowly added, and the temperature is raised to 60-70°C, reacted for 1 hour, and then cooled to room temperature; a solvent is added, stirred evenly, and the material is discharged to obtain an addition-type potting adhesive primer liquid.

8. Use of the addition type potting glue primer according to any one of claims 1 to 6 or the addition type potting glue primer prepared by the preparation method according to claim 7 in the internal potting of an LED driver power supply.

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