CN112694863B

CN112694863B - Single-component polyurethane electronic component fixing glue and preparation method and application thereof

Info

Publication number: CN112694863B
Application number: CN202011624815.9A
Authority: CN
Inventors: 赵景左; 贾云龙; 张虎极; 唐礼道; 章锋
Original assignee: Guangzhou Huitian New Material Co ltd; Shagnhai Huitian New Chemical Materials Co ltd; Huitian New Material Co ltd
Current assignee: Guangzhou Huitian New Material Co ltd; Shagnhai Huitian New Chemical Materials Co ltd; Huitian New Material Co ltd
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2022-09-06
Anticipated expiration: 2040-12-31
Also published as: CN112694863A

Abstract

The invention provides a single-component polyurethane electronic component fixing glue, a preparation method and application thereof, wherein the single-component polyurethane electronic component fixing glue comprises the following components in parts by weight: 20-40 parts of isocyanate group-containing prepolymer, 0.1-0.4 part of silane coupling agent, 40-50 parts of flame-retardant powder, 10-30 parts of flame-retardant thixotropic agent, 0.3-1 part of antioxidant, 0.3-1 part of light stabilizer and 0.5-3 parts of latent curing agent; wherein, the content of the isocyanate group in the prepolymer is 2.0 to 2.5 weight percent. The polyether polyol is used as a main raw material of the prepolymer, the crosslinking degree is high, the prepared electronic fixing adhesive has certain high strength and elasticity, and the silane coupling agent in the composition is matched to generate good adhesive force and have excellent damp-heat aging resistance; the polyurea compound is selected as the flame-retardant thixotropic agent, so that good thixotropy is provided for the fixing glue.

Description

Single-component polyurethane electronic component fixing glue and preparation method and application thereof

Technical Field

The invention belongs to the technical field of adhesive preparation, and particularly relates to a single-component polyurethane electronic component fixing glue, and a preparation method and application thereof.

Background

The electronic component fixing glue can play the roles of water resistance, moisture resistance, dust resistance, insulation, heat conduction, confidentiality, corrosion resistance, temperature resistance, flame retardance, shock resistance and the like after being glued and cured, and can effectively protect the electronic components, thereby prolonging the service life of the electronic components.

The most original fixing mode of electronic components is potting adhesive fixing, wherein the epoxy resin type potting adhesive has the characteristics of small shrinkage rate, no by-product and electric insulation, but is limited by a molecular structure and is easy to crack after cold and heat cycles are resisted, so that the epoxy resin type potting adhesive can only be used for potting the electronic components at normal temperature.

In order to solve the problem that epoxy resin pouring sealant is easy to crack after being subjected to cold and hot cycles, the organic silicon pouring sealant is researched and developed, has wide application temperature range, can normally work at minus 50-250 ℃, has the advantages of high and low temperature resistance, electrical insulation, oxidation resistance stability, weather resistance, flame retardancy, hydrophobicity, corrosion resistance, no toxicity, no odor, physiological inertia and the like, cannot deform in the mechanical processing process after being applied with glue and cured, has excellent electrical property and good physical and mechanical properties, can be suitable for special fields with harsh working environment conditions, and has low modulus and hardness and poor earthquake resistance after being fixed.

The polyurethane pouring sealant has strong environmental adaptability, good anti-seismic performance and good cold and hot cycle resistance, but in the practical application process, the pouring sealant has too soft surface, is easy to bubble, is insufficiently cured, is easy to become brittle after high-temperature curing, has poor toughness, short aging life, poor ultraviolet resistance, easy discoloration and poor acid and alkali resistance.

Disclosure of Invention

In order to overcome the defects of the polyurethane pouring sealant in the prior art, the invention aims to provide the single-component polyurethane electronic component fixing glue, the preparation method and the application thereof, so as to overcome the defects of easy foaming, short aging life and poor ultraviolet resistance, and the single-component polyurethane electronic component fixing glue has thixotropic viscosity, can save the using amount and reduce the production cost compared with other pouring sealants, can be directly used for gluing to be adhered and fixed between an electronic component and a PCB (printed circuit board), and has the advantages of good adhesion, simple construction and wide application range.

In order to achieve the purpose, the invention adopts the following technical scheme:

a single-component polyurethane electronic component fixing glue comprises the following components in parts by weight:

wherein the content of isocyanate group in the prepolymer is 2.0-2.5 wt%.

Specifically, if the content of the isocyanate group in the prepolymer is less than 2.0 wt%, the prepared adhesive has poor adhesion, is not high in temperature and humidity resistance, and is easy to peel; if the content of the isocyanate group in the prepolymer is more than 2.5 wt%, the prepared rubber has high crosslinking density, low elongation at break and easy foaming under high temperature and high humidity conditions.

In the technical scheme, the prepolymer is prepared by polymerizing 10-20 parts of difunctional-trifunctional isocyanate compound, 70-80 parts of polyether polyol, 0-15 parts of plasticizer and 0-0.05 part of catalyst, wherein the molar ratio of the isocyanate compound to the polyether polyol is 1.8-2.4: 1.

preferably, in the above technical solution, the molecular weight of the polyether polyol is 4000-6000, and the hydroxyl functionality is 3.

Further, in the above technical solution, the difunctional-trifunctional isocyanate compound is diphenylmethane diisocyanate and/or toluene-2, 4-diisocyanate, preferably diphenylmethane diisocyanate.

Further, in the above technical solution, one or more of the polyether polyols EP-330NG, EP3600, T-5A and F3135.

Further, in the above technical solution, the plasticizer is one of alkyl sulfonate plasticizer, phthalate plasticizer and cumylphenyl phosphate flame retardant plasticizer, and is preferably one of T-50, DIDP, DINP and IPPP.

Further, in the above technical solution, the catalyst is an organotin catalyst, preferably dibutyltin dilaurate or stannous octoate.

In the technical scheme, the silane coupling agent is one or more of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane, beta- (3, 4-epoxycyclohexyl) ethyl trimethoxy silane, gamma-isocyanate propyl trimethoxy silane and gamma-isocyanate propyl triethoxy silane.

Specifically, by adopting the silane coupling agent, the siloxane end of the silane coupling agent can be utilized to act with the electronic component and the PCB substrate interface, so that good adhesive force is generated, and the humidity resistance, heat resistance and aging resistance of the prepared polyurethane electronic component fixing glue are further improved.

Further, in the above technical solution, the flame retardant powder is aluminum hydroxide powder and/or magnesium hydroxide powder, and the average particle size is 1-30 μm.

Specifically, the aluminum hydroxide powder and the magnesium hydroxide powder do not influence the stability of the polyurethane adhesive, and the pH value or the crystal water content of the rest flame-retardant powder can influence the curing speed and the storage stability of the adhesive; in addition, the particle size is too high, the graininess of the prepared gum is remarkable, and the final strength is also lowered.

Preferably, in the technical scheme, the flame retardant powder is one or more of ACW-5, ACW-8, ACW-10, ACW-1500, MHS-7, MHS-10 and MHS-25, and further preferably ACW-1500.

Further, in the above technical scheme, the flame-retardant thixotropic agent is prepared from the following components in a mass ratio of 0.8-1.2: 0.8-1.2 of polyurea compound prepared by reacting raw material A and raw material B, wherein the raw material A is prepared by reacting 60-90 parts of flame-retardant plasticizer and 10-30 parts of organic amine, and the raw material B is prepared by reacting 60-90 parts of flame-retardant plasticizer and 20-40 parts of aromatic isocyanate.

Preferably, in the above technical solution, the flame retardant plasticizer is an organic phosphate flame retardant plasticizer, the organic amine is mono-n-butylamine and/or di-n-butylamine, and the aromatic isocyanate is toluene-2, 4-diisocyanate or diphenylmethane diisocyanate.

Specifically, in a specific embodiment of the present invention, the flame retardant plasticizer is one of triethyl phosphate, tributyl phosphate, trioctyl phosphate, ditolyl phosphate, triphenyl phosphate, tricresyl phosphate, diphenylisooctyl phosphate, diphenylisodecyl phosphate, cumylphenyl phosphate, xylylene diphenyl phosphate, tetraphenylresorcinol diphosphate, tetraphenyl bisphenol a diphosphate, bisphenol a bis (diphenyl) phosphate, and the aromatic isocyanate is diphenylmethane diisocyanate.

Further, in the above technical scheme, the antioxidant is one or more of a hindered phenol antioxidant, an aromatic secondary amine antioxidant and a phosphite ester auxiliary antioxidant, specifically, one or more of antioxidant 245, antioxidant 1035, antioxidant 1076, antioxidant 1098, antioxidant 1135, antioxidant 5057 and antioxidant 168.

Further, in the technical scheme, the light stabilizer is one or more of triazole ultraviolet absorbers, benzophenone ultraviolet absorbers, salicylate ultraviolet absorbers and hindered amine light stabilizers, specifically one or more of UV-326, UV-327, UV-328, UV-571, UV-1130, light stabilizers 292, 765, 622 and 770.

Further, in the above technical solution, the latent curing agent is an oxazolidine latent curing agent and/or a macromolecular aldimine latent curing agent, specifically one or more of ALT-101, ALT-301, ALT-401, ALT-402, ALT-403, SL-101 and SL-401.

Still further, in the above technical scheme, the single-component polyurethane electronic component fixing glue further comprises 0-0.2 parts of a water-absorbing stabilizer and/or 0-0.2 parts of a coloring agent.

Preferably, in a specific embodiment of the present invention, the water absorption stabilizer Ti water absorbing agent.

Preferably, in a particular embodiment of the invention, the colorant is carbon black M570.

The invention also provides a preparation method of the single-component polyurethane electronic component fixing glue, which comprises the following steps:

s1, preparing a prepolymer with the content of isocyanate groups of 2.0-2.5 wt%;

s2, preparing a raw material A by adopting a flame-retardant plasticizer and organic amine, preparing a raw material B by adopting the flame-retardant plasticizer and aromatic isocyanate, extruding the raw materials A and B by a double screw, and then grinding the raw materials A and B in a colloid mill at the temperature of less than 120 ℃ to prepare a flame-retardant thixotropic agent;

s3, respectively weighing the prepolymer containing isocyanate groups, the water absorption stabilizer, the silane coupling agent, the antioxidant and the light stabilizer according to the proportion, placing the prepolymer, the water absorption stabilizer, the silane coupling agent, the antioxidant and the light stabilizer into a stirring kettle, adding the flame-retardant powder and the coloring agent which are dried in advance according to the proportion, uniformly stirring under a vacuum condition, removing the vacuum by using dry nitrogen, adding the flame-retardant thixotropic agent and the latent curing agent according to the proportion, and uniformly stirring.

Wherein, the steps S1 and S2 can be performed in sequence or simultaneously, and the environmental temperature and the environmental relative humidity in the preparation process are respectively less than or equal to 25 ℃ and less than or equal to 55% RH.

Preferably, in the above technical scheme, in step S1, the reaction temperature and the reaction time in the preparation process of the prepolymer are 75-80 ℃ and 2-4h, respectively.

The invention also provides application of the single-component polyurethane electronic component fixing glue or the preparation method of the single-component polyurethane electronic component fixing glue in electronic component potting.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention selects polyether polyol with the molecular weight of 4000-6000 and the hydroxyl functionality of 3 as the main raw material of the prepolymer, has high crosslinking degree, ensures that the prepared electronic fixing adhesive has certain high strength and certain elasticity, is matched with the silane coupling agent in the composition, has the siloxane end capable of acting with the interface of an electronic component and a PCB (printed circuit board) base material to generate good adhesive force, and has excellent humidity, heat and aging resistance;

(2) the flame-retardant powder selected by the invention has good dispersibility with the main resin, particularly the flame-retardant powder after surface modification treatment, can improve the adhesion to a base material, and can make the prepared electronic fixing adhesive reach UL-94 flame-retardant certification V0 level by matching with the flame-retardant plasticizer and the flame-retardant thixotropic agent;

(3) the flame-retardant thixotropic agent selected by the invention is a polyurea compound, has good stability in a polyurethane system, does not thicken gel, provides good thixotropy for the fixing adhesive, and can play a role in shock-proof protection for the electronic components;

(4) the antioxidant and the light stabilizer selected by the invention can effectively prevent the influence of ultraviolet light on the broken bond of the polyurethane chain segment and can prevent the fixing glue from yellowing and performance attenuation at the use temperature of electronic products;

(5) the oxazolidine latent curing agent selected by the invention can react with moisture in advance, and the released catalyst reacts with isocyanate, so that the fixing glue of the invention can be applied at the temperature of 30-40 ℃ without foaming and bulging;

(6) the preparation method of the single-component polyurethane electronic component fixing glue provided by the invention is simple and controllable, the used raw materials are common and easy to obtain, and the equipment used in the production process is common equipment in the industry, so that the single-component polyurethane electronic component fixing glue is suitable for large-scale production.

Detailed Description

The present invention is further described in detail below with reference to specific examples so that those skilled in the art can more clearly understand the present invention.

The following examples are provided only for illustrating the present invention and are not intended to limit the scope of the present invention.

Unless otherwise specified, the technical means used in the examples of the present invention are conventional means well known to those skilled in the art.

The starting materials used in the examples of the present invention are all commercially available products unless otherwise specified.

All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative effort shall fall within the protection scope of the present invention.

Example 1

The embodiment of the invention provides a single-component polyurethane electronic component fixing glue and a preparation method thereof, and the single-component polyurethane electronic component fixing glue specifically comprises the following steps:

1) taking 10-20 wt% of Wanhua chemical MDI (diphenylmethane diisocyanate) and 70-80 wt% of Wanhua chemical F3135, wherein the mol ratio of the MDI to the F3135 is 1.8-2.4: 1, adding 0-15 wt% of IPPP plasticizer, adding the materials into a reaction kettle under the protection of nitrogen, heating to 75-80 ℃, carrying out heat preservation reaction for 2-4h, controlling the percentage content of isocyanate groups to be 2.0-2.5%, discharging for later use, and preparing a prepolymer 1 containing the isocyanate groups;

2) the mol ratio of Wanhua chemical MDI to mono-n-butylamine is 1: 1, adding 80-90 wt% of IPPP and 10-20 wt% of mono-n-butylamine into a stirring kettle 1, stirring for 20min, using after 8h, calculating as material A, adding 70-80 wt% of IPPP into a reaction kettle 2, stirring and heating to 50 ℃, adding 20-30 wt% of Wanhua chemical MDI, introducing nitrogen, stirring to a uniform solution, keeping the temperature of 50-55 ℃ without white or other impurities. The material B is calculated, and the mass ratio of the material A to the material B is 1: 1, extruding by a double screw, grinding by a colloid mill at the temperature of below 120 ℃ and discharging for later use to prepare a flame-retardant thixotropic agent 1;

3) adding (A)20-40 wt% of prepolymer 1 containing isocyanate group into a planetary stirring kettle according to the proportion; (B)0-0.2 wt% of a water absorption stabilizer; (C)0.1-0.4 wt% of gamma- (2, 3-glycidoxy) propyltrimethoxysilane coupling agent; (G)0.3-1.0 wt% of antioxidant 1135; (H)0.3-1.0 wt% of light stabilizer 292 is added with pre-dried (D)40-50 wt% of Shanghai Asahi Sensen flame retardant powder ACW-1500 after being evenly stirred; (E)0-0.2 wt% of carbon black is uniformly stirred in a vacuum state, and 10-30 wt% of self-made flame retardant thixotropic agent 1 is added after the vacuum is relieved by dry nitrogen; (I)0.5-3 wt% of ALT-101 latent curing agent in the Ailite chemical industry, and discharging after uniformly stirring; filling into a closed container for later use.

Example 2

1) taking 10-20 wt% of Wanhua chemical TDI and 70-80 wt% of Lanxindong Daihong chemical industry EP3600 according to the mol ratio of 1.8-2.4: 1, adding 0-15 wt% of T-50 plasticizer, putting the materials into a reaction kettle under the protection of nitrogen, heating to 75-80 ℃, carrying out heat preservation reaction for 2-4h, controlling the percentage content of isocyanate groups to be 2.0-2.5%, discharging for later use, and preparing a prepolymer 2 containing the isocyanate groups;

2) the mol ratio of Wanhua chemical MDI to mono-n-butylamine is 1: 1, adding 80-90 wt% of bisphenol A bis (diphenyl) phosphate and 10-20 wt% of mono-n-butylamine into a stirring kettle 1, stirring for 20min, using after 8h, counting as material A, adding 70-80 wt% of bisphenol A bis (diphenyl) phosphate into a reaction kettle 2, stirring and heating to 50 ℃, adding 20-30 wt% of Wanhua chemical MDI, introducing nitrogen, stirring to a uniform solution, keeping the temperature at 50-55 ℃ without white or other impurities, counting as material B, wherein the feeding ratio of the material A to the material B is 1: 1, extruding by a double screw, grinding by a colloid mill at the temperature of below 120 ℃ and discharging for later use to prepare a flame-retardant thixotropic agent 2;

3) adding (A)20-40 wt% of prepolymer 2 containing isocyanate group into a planetary stirring kettle according to the proportion; (B)0-0.2 wt% of a water absorption stabilizer; (C)0.1-0.4 wt% beta- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane; (G)0.3-1 wt% 1035 antioxidant; (H)0.3-1 wt% of UV-328 ultraviolet absorbent, and adding pre-dried (D)40-50 wt% of Shanghai Asahi ACW-8 flame-retardant powder; (E)0-0.2 wt% of carbon black is uniformly stirred in a vacuum state, and 10-30 wt% of self-made flame retardant thixotropic agent 2 is added after the vacuum is relieved by dry nitrogen; (I)0.5-3 wt% of SL-101 latent curing agent in Guangzhou Sen Pola chemical industry, uniformly stirring and discharging; filling into a closed container for later use.

Example 3

1) taking 10-20 wt% of Wanhua chemical MDI and 70-80 wt% of Lanxindong chemical industry EP3600 according to the mol ratio of 1.8-2.4: 1, adding 0-15 wt% of DIDP plasticizer, putting the materials into a reaction kettle under the protection of nitrogen, heating to 75-80 ℃, keeping the temperature for reaction for 2-4h, controlling the percentage content of isocyanate groups to be 2.0-2.5%, discharging for later use, and preparing a prepolymer 3 containing the isocyanate groups;

2) the mol ratio of Wanhua chemical MDI to di-n-butylamine is 1: 1, adding 80-90 wt% of diphenyl isooctyl phosphate and 10-20 wt% of di-n-butylamine into a stirring kettle 1, stirring for 20min, using after 8h, and calculating as material A, adding 70-80 wt% of diphenyl isooctyl phosphate into a reaction kettle 2, stirring and heating to 50 ℃, adding 20-30 wt% of Wanhua chemical MDI, introducing nitrogen, stirring to a uniform solution, keeping the temperature at 50-55 ℃ without white or other impurities, calculating as material B, wherein the feeding ratio of the material A to the material B is 1: 1, extruding by a double screw, grinding by a colloid mill at a temperature of below 120 ℃ and discharging for later use to prepare a flame-retardant thixotropic agent 3;

3) adding (A)20-40 wt% of prepolymer 3 containing isocyanate group into a planetary stirring kettle according to the proportion; (B)0-0.2 wt% of a water absorption stabilizer; (C)0.1-0.4 wt% gamma-isocyanatopropyltrimethoxysilane; (G)0.3-1 wt% 245 antioxidant; (H)0.3-1 wt% UV-326 UV absorber, stirring well, adding pre-dried (D)40-50 wt% Shanghai Asahi MHS-25 flame retardant powder; (E)0-0.2 wt% of carbon black is uniformly stirred in a vacuum state, and 10-30 wt% of self-made flame retardant thixotropic agent 3 is added after the vacuum is relieved by dry nitrogen; (I)0.5-3 wt% of SL-401 latent curing agent in Guangzhou Sen Pola chemical industry, and discharging after uniformly stirring; filling into a closed container for later use.

Example 4

1) taking 10-20 wt% of Wanhua chemical MDI and 70-80 wt% of Lanxindong Dahua EP-330NG, wherein the mol ratio of the Wanhua chemical MDI to the Lanxindong Dahua chemical MDI is 1.8-2.4: 1, adding 0-15 wt% of DINP plasticizer, putting the materials into a reaction kettle under the protection of nitrogen, heating to 75-80 ℃, carrying out heat preservation reaction for 2-4h, controlling the percentage content of isocyanate groups to be 2.0-2.5%, discharging for later use, and preparing a prepolymer 4 containing the isocyanate groups;

2) the mol ratio of Wanhua chemical MDI to mono-n-butylamine is 1: 1, adding 80-90 wt% of dimethylbenzene diphenyl phosphate and 10-20 wt% of mono-n-butylamine into a stirring kettle 1, stirring for 20min, using after 8h, calculating material A, adding 70-80 wt% of dimethylbenzene diphenyl phosphate into a reaction kettle 2, stirring and heating to 50 ℃, adding 20-30 wt% of Wanhua chemical MDI, introducing nitrogen, stirring to a uniform solution, keeping the temperature at 50-55 ℃ without white or other impurities, calculating material B, wherein the feeding ratio of the material A to the material B is 1: 1, extruding by a double screw, grinding by a colloid mill at a temperature of below 120 ℃ and discharging for later use to prepare a flame-retardant thixotropic agent 4;

3) adding 20-40 wt% of prepolymer 4 containing isocyanate group into a planetary stirring kettle according to the proportion; (B)0-0.2 wt% of a water absorption stabilizer; (C)0.1-0.4 wt% gamma-isocyanatopropyltriethoxysilane; (G)0.3-1 wt% 268 antioxidant; (H)0.3-1 wt% of 622 light stabilizer, adding 40-50 wt% of (D) the pre-dried Shanghai Asahi ACW-10 flame-retardant powder after uniformly stirring; (E)0-0.2 wt% of carbon black is uniformly stirred in a vacuum state, and 10-30 wt% of self-made flame retardant thixotropic agent 4 is added after the vacuum is relieved by dry nitrogen; (I)0.5-3 wt% of ALT-301 latent curing agent in the Ailite chemical industry, and discharging after uniformly stirring; filling into a closed container for later use.

Comparative example 1

The invention provides a single-component polyurethane electronic component fixing glue and a preparation method thereof, and the single-component polyurethane electronic component fixing glue specifically comprises the following steps:

1) similar to example 1, 10-20 wt% of Wanhua chemical MDI and 70-80 wt% of Wanhua chemical F3135 are taken, and the molar ratio is 1.8-2.4: 1, adding 0-15 wt% of IPPP plasticizer, adding the materials into a reaction kettle under the protection of nitrogen, heating to 75-80 ℃, carrying out heat preservation reaction for 2-4h, controlling the percentage content of isocyanate groups to be 2.0-2.5%, discharging for later use, and preparing a prepolymer 1 containing the isocyanate groups;

2) the mol ratio of Wanhua chemical MDI to mono-n-butylamine is 1: 1, carrying out feeding design. Adding 80-90 wt% of DIDP and 10-20 wt% of mono-n-butylamine into a stirring kettle 1, stirring for 20min, using after 8h, calculating material A, adding 70-80 wt% of DIDP into a reaction kettle 2, stirring and heating to 50 ℃, adding 20-30 wt% of Wanhua chemical MDI, introducing nitrogen, stirring to obtain a uniform solution, keeping the temperature at 50-55 ℃ without white or other impurities, calculating material B, wherein the feeding ratio of the material A to the material B is 1: 1, extruding by a double screw, grinding by a colloid mill at the temperature of below 120 ℃ and discharging for later use to prepare a flame-retardant thixotropic agent 1-b;

3) adding (A)20-40 wt% of prepolymer 1 containing isocyanate group into a planetary stirring kettle according to the proportion; (B)0-0.2 wt% of a water absorption stabilizer; (C)0.1-0.4 wt% of gamma- (2, 3-glycidoxy) propyltrimethoxysilane coupling agent; (G)0.3-1 wt% 1135 antioxidant; (H)0.3-1 wt% 292 light stabilizer, adding pre-dried (D)40-50 wt% Shanghai Asahi ACW-1500 flame retardant powder; (E)0-0.2 wt% of carbon black is uniformly stirred in a vacuum state, and 10-30 wt% of self-made flame retardant thixotropic agent 1-b is added after vacuum is relieved by dry nitrogen; (I)0.5-3 wt% of ALT-101 latent curing agent in the Ailite chemical industry, and discharging after uniformly stirring; filling into a closed container for later use.

Comparative example 2

1) similar to example 2, 10-20 wt% of Wanhua chemical TDI and 70-80 wt% of Lanxindong Daihong chemical EP3600 are taken according to the molar ratio of 1.8-2.4: 1, adding 0-15 wt% of T-50 plasticizer, putting the materials into a reaction kettle under the protection of nitrogen, heating to 75-80 ℃, and carrying out heat preservation reaction for 2-4 hours. Controlling the percentage content of the isocyanate group to be 2.0-2.5%, discharging for standby, and preparing a prepolymer 2 containing the isocyanate group;

2) analogously to example 2, with a molar ratio of Wanhua chemical MDI to mono-n-butylamine of 1: 1, adding 80-90 wt% of bisphenol A bis (diphenyl) phosphate and 10-20 wt% of mono-n-butylamine into a stirring kettle 1, stirring for 20min, and using after 8h to obtain the material A. Adding 70-80 wt% of bisphenol A bis (diphenyl) phosphate into a reaction kettle 2, stirring and heating to 50 ℃, adding 20-30 wt% of Wanhua chemical MDI, introducing nitrogen, stirring to obtain a uniform solution, keeping the temperature at 50-55 ℃ without white or other impurities. The material B is calculated, and the feeding ratio of the material A to the material B is 1: 1, extruding by a double screw, grinding by a colloid mill at a temperature of below 120 ℃ and discharging for later use to prepare a flame-retardant thixotropic agent 2;

3) adding (A)20-40 wt% of prepolymer 2 containing isocyanate group into a planetary stirring kettle according to the proportion; (B)0-0.2 wt% of a water absorption stabilizer; (C)0.1-0.4 wt% beta- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane; (G)0.3-1 wt% 1035 antioxidant; (H)0.3-1 wt% of UV-328 ultraviolet absorbent, and adding pre-dried (D)40-50 wt% of Shanghai XuSen ACW-8 flame-retardant powder; (E)0 to 0.2 weight percent of carbon black is evenly stirred in a vacuum state, and 10 to 30 weight percent of self-made flame retardant thixotropic agent 2 is added after the vacuum is relieved by dry nitrogen; (I)0.5-3 wt% of dibutyltin dilaurate catalyst, uniformly stirring and then discharging; filling into a closed container for later use.

Comparative example 3

1) similar to example 3, 10-20 wt% of Wanhua chemical MDI and 70-80 wt% of Lanxindong chemical industry EP3600 are taken, and the molar ratio is 1.8-2.4: 1, adding 0-15 wt% of DIDP plasticizer, putting the materials into a reaction kettle under the protection of nitrogen, heating to 75-80 ℃, keeping the temperature for reaction for 2-4h, controlling the percentage content of isocyanate groups to be 2.0-2.5%, discharging for later use, and preparing a prepolymer 3 containing the isocyanate groups;

2) analogously to example 3, the molar ratio of Wanhua chemical MDI to di-n-butylamine was 1: 1, adding 80-90 wt% of diphenyl isooctyl phosphate and 10-20 wt% of di-n-butylamine into a stirring kettle 1, stirring for 20min, using after 8h, and calculating as material A, adding 70-80 wt% of diphenyl isooctyl phosphate into a reaction kettle 2, stirring and heating to 50 ℃, adding 20-30 wt% of Wanhua chemical MDI, introducing nitrogen, stirring to a uniform solution, keeping the temperature at 50-55 ℃ without white or other impurities, calculating as material B, wherein the feeding ratio of the material A to the material B is 1: 1, extruding by a double screw, grinding by a colloid mill at the temperature of below 120 ℃ and discharging for later use to prepare a flame-retardant thixotropic agent 3;

3) adding (A)20-40 wt% of prepolymer 3 containing isocyanate group into a planetary stirring kettle according to the proportion; (B)0-0.2 wt% of a water absorption stabilizer; (C)0.1-0.4 wt% gamma-isocyanatopropyltrimethoxysilane; (G)0.3-1 wt% 245 antioxidant; (H)0.3-1 wt% UV-326 ultraviolet absorbent, adding pre-dried (D)40-50 wt% Europe CARB2 calcium carbonate powder; (E)0-0.2 wt% of carbon black is uniformly stirred in a vacuum state, and 10-30 wt% of self-made flame retardant thixotropic agent 3 is added after the vacuum is relieved by dry nitrogen; (I)0.5-3 wt% of SL-401 latent curing agent in Guangzhou Sen Pola chemical industry, and discharging after uniformly stirring; filling into a closed container for later use.

Comparative example 4

1) similar to example 4, 10-20 wt% of Wanhua chemical MDI and 70-80 wt% of Lanxindong Dahua co-EP-330 NG are taken, and the molar ratio is 1.8-2.4: 1, adding 0-15 wt% of DINP plasticizer, adding the materials into a reaction kettle under the protection of nitrogen, heating to 75-80 ℃, carrying out heat preservation reaction for 2-4h, controlling the percentage content of isocyanate groups to be 2.0-2.5%, discharging for later use, and preparing a prepolymer 4 containing the isocyanate groups;

2) analogously to example 4, the molar ratio of Wanhua chemical MDI to mono-n-butylamine was 1: 1, adding 80-90 wt% of diphenyl xylene phosphate and 10-20 wt% of mono-n-butylamine into a stirring kettle 1, stirring for 20min, using after 8h, calculating as material A, adding 70-80 wt% of diphenyl xylene phosphate into a reaction kettle 2, stirring and heating to 50 ℃, adding 20-30 wt% of Wanhua chemical MDI, introducing nitrogen, stirring to a uniform solution, keeping the temperature at 50-55 ℃ without white or other impurities, calculating as material B, wherein the feeding ratio of the material A to the material B is 1: 1, extruding by a double screw, grinding by a colloid mill at the temperature of below 120 ℃ and discharging for later use to prepare a flame-retardant thixotropic agent 4;

3) adding (A)20-40 wt% of prepolymer 4 containing isocyanate group into a planetary stirring kettle according to the proportion; (B)0-0.2 wt% of a water absorption stabilizer; (C)0.1-0.4 wt% gamma-isocyanatopropyltriethoxysilane; (G)0 wt% of an antioxidant; (H)0 wt% of light stabilizer is added into the mixture after being evenly stirred, and then 40 to 50 wt% of pre-dried (D) Shanghai Asahsen ACW-10 flame retardant powder is added; (E)0-0.2 wt% of carbon black is uniformly stirred in a vacuum state, and 10-30 wt% of self-made flame retardant thixotropic agent 4 is added after the vacuum is relieved by dry nitrogen; (I)0.5-3 wt% of ALT-301 latent curing agent in the Ailite chemical industry, and discharging after uniformly stirring; filling into a sealed container for later use.

And (3) performance testing:

surface drying time: the test was carried out according to the regulation of method 8.2B of GB/T13477.5-2002.

Tensile strength and elongation at break: tested according to GB/T528-.

Foaming and bulging: and (3) applying the adhesive on a PCB test substrate, wherein the thickness of the adhesive tape is 2-3mm, and the width of the adhesive tape is 5 mm. And (3) curing the adhesive tape at the temperature of 30-40 ℃ and the humidity of 50% RH, and observing whether the adhesive tape is foamed and swelled.

Aging and color changing: and (3) after the polyurethane fixing glue is bonded with the PCB (printed Circuit Board) of the test substrate, curing for 7 days, placing the PCB at 115 ℃ for 3d, and observing whether the PCB is discolored.

Ultraviolet ray resistance: according to GB/T14522-2008, putting the cured film for 7 days into an ultraviolet aging box with a spray, aging for a specified time, and taking out; after water spraying, the mixture is wiped for 3 to 5 times by using a clean absorbent cotton ball to see whether cracks occur or not and whether black spots are obvious or not.

Flame retardant property: the test is carried out according to the UL94-V0 grade.

High temperature high humidity aging peel adhesion: after the polyurethane fixing glue is bonded with a PCB (printed Circuit Board) of a test substrate, the PCB is cured for 7 days, placed in saturated moisture at 70 ℃ for 7 days, then placed at 23 ℃/50% RH for 2 hours, and then subjected to knife cutting verification.

The actual amounts (parts by weight) of the raw materials used in the preparation of the isocyanate group-containing prepolymers according to the preparation procedures of the polyurethane fixing adhesives of the above examples and comparative examples are shown in Table 1, to obtain the following isocyanate group-containing prepolymers.

TABLE 1 actual amount (parts by weight) of isocyanate group-containing prepolymer

The actual amounts (parts by weight) of the respective raw materials added in the production process of the flame-retardant thixotropic agent according to the production flow of the polyurethane fixing adhesives of the above examples and comparative examples are shown in Table 2, to obtain the following flame-retardant thixotropic agents.

TABLE 2 actual amount of flame-retardant thixotropic agent added (parts by weight)

According to the preparation flow of the polyurethane fixing glue, the actual addition amount (parts by weight) of each raw material in the preparation process of the single-component polyurethane electronic component fixing glue is shown in table 3, and the following single-component polyurethane electronic component fixing glue is obtained.

TABLE 3 actual addition of one-component polyurethane electronic component mounting adhesive (parts by weight)

The one-component polyurethane electronic component part-fixing adhesives obtained in examples 1 to 4 and comparative examples 1 to 4 were tested for their properties, and the results are shown in table 4 below.

Table 4 performance test results of the one-component polyurethane electronic component fixing adhesive

Finally, the method of the present invention is only a preferred embodiment and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A single-component polyurethane electronic component fixing glue is characterized in that,

the paint comprises the following components in parts by weight:

wherein, the content of isocyanate group in the prepolymer is 2.0-2.5 wt%;

the flame-retardant thixotropic agent is prepared from the following components in percentage by mass of 0.8-1.2: 0.8-1.2 parts of polyurea compound prepared by reacting raw material A and raw material B, wherein the raw material A is prepared by reacting 60-90 parts of flame-retardant plasticizer and 10-30 parts of organic amine, and the raw material B is prepared by reacting 60-90 parts of flame-retardant plasticizer and 20-40 parts of aromatic isocyanate; the flame-retardant plasticizer is an organic phosphate flame-retardant plasticizer, the organic amine is mono-n-butylamine and/or di-n-butylamine, and the aromatic isocyanate is toluene-2, 4-diisocyanate or diphenylmethane diisocyanate.

2. The single-component polyurethane electronic component fixing glue according to claim 1, wherein the prepolymer is polymerized from 10-20 parts of difunctional-trifunctional isocyanate compound, 70-80 parts of polyether polyol, 0-15 parts of plasticizer and 0-0.05 part of catalyst, wherein the molar ratio of the isocyanate compound to the polyether polyol is 1.8-2.4: 1.

3. the one-component polyurethane electronic component fixing glue as claimed in claim 2, wherein the difunctional-trifunctional isocyanate compound is diphenylmethane diisocyanate and/or toluene-2, 4-diisocyanate;

and/or the polyether polyol is one or more of EP-330NG, EP3600, T-5A and F3135;

and/or the plasticizer is one of alkyl sulfonate plasticizer, phthalate plasticizer and cumyl phenyl phosphate flame retardant plasticizer;

and/or, the catalyst is an organotin catalyst.

4. The one-component polyurethane electronic component fixing glue as claimed in claim 1, wherein the silane coupling agent is one or more of gamma- (2, 3-epoxypropoxy) propyltrimethoxysilane, beta- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, gamma-isocyanate propyltrimethoxysilane and gamma-isocyanate propyltriethoxysilane.

5. The one-component polyurethane electronic component fixing glue according to any one of claims 1 to 4, wherein the flame retardant powder is aluminum hydroxide powder and/or magnesium hydroxide powder, and the average particle size of the flame retardant powder is 1 to 30 μm.

6. The one-component polyurethane electronic component fixing glue according to any one of claims 1 to 4, wherein the flame retardant plasticizer is one of triethyl phosphate, tributyl phosphate, trioctyl phosphate, ditolyl phosphate, triphenyl phosphate, tricresyl phosphate, diphenylisooctyl phosphate, diphenylisodecyl phosphate, cumylphenyl phosphate, xylenyldiphenyl phosphate, tetraphenylresorcinol diphosphate, tetraphenyl bisphenol A diphosphate, bisphenol A bis (diphenyl) phosphate, and the aromatic isocyanate is diphenylmethane diisocyanate.

7. The single-component polyurethane electronic component fixing glue according to any one of claims 1 to 4, wherein the antioxidant is one or more of a hindered phenol antioxidant, an aromatic secondary amine antioxidant and a phosphite ester auxiliary antioxidant;

and/or the light stabilizer is one or more of triazole ultraviolet absorbers, benzophenone ultraviolet absorbers, salicylate ultraviolet absorbers and hindered amine light stabilizers;

and/or the latent curing agent is an oxazolidine latent curing agent and/or a macromolecular aldimine latent curing agent.

8. The one-component polyurethane electronic component fixing glue according to any one of claims 1 to 4, further comprising 0 to 0.2 parts of a water-absorbing stabilizer and/or 0 to 0.2 parts of a coloring agent.

9. The preparation method of the one-component polyurethane electronic component fixing glue as claimed in any one of claims 1 to 8, comprising:

s3, respectively weighing the prepolymer containing the isocyanate group, the water absorption stabilizer, the silane coupling agent, the antioxidant and the light stabilizer according to the proportion, placing the prepolymer, the water absorption stabilizer, the silane coupling agent, the antioxidant and the light stabilizer into a stirring kettle, adding the flame-retardant powder and the coloring agent which are dried in advance according to the proportion, uniformly stirring under a vacuum condition, removing the vacuum by using dry nitrogen, adding the flame-retardant thixotropic agent and the latent curing agent according to the proportion, and uniformly stirring;

10. The use of the one-component polyurethane electronic component fixing glue according to any one of claims 1 to 8 or the one-component polyurethane electronic component fixing glue prepared by the preparation method according to claim 9 in electronic component potting.