WO2020078115A1 - Arc-suppression slurry for fuse and preparation method therefor - Google Patents

Abstract

An arc-suppression slurry for a fuse, comprising the following components in weight percentage: 10-35% of thermoplastic phenol-formaldehyde resin double-modified by boric acid and a silane coupling agent; 20-65% modified magnesium hydroxide, 1-5% of microencapsulated red phosphorus; 5-40% of organic solvent; and 0.6-4% of hexamethylenetetramine. The phenol-formaldehyde resin is double-modified by boric acid and a silane coupling agent, and modified magnesium hydroxide and microencapsulated red phosphorus and are added as a composite flame retardant; thus, the electrical insulation, heat resistance, ablation resistance, transient high temperature resistance, and flame retardancy of the thermoplastic phenol-formaldehyde resin are greatly improved, and the arc-suppression slurry has stronger mechanical property after solidifying around the fuse element. The arc-suppression slurry can surround the fuse element by means of filling or thick film printing, so that the breaking capacity of the fuse can meet an application above 250 VAC/100 A. The invention has the obvious advantages of low production costs, being halogen-free and environment-friendly, strong arc suppression capability, etc., and is suitable for common shell-tube or thick film printed surface mount miniature fuses.

Description

[Corrected according to Rule 26 11.09.2019] —A kind of arc-extinguishing slurry for fuse and its preparation method Technical field

The invention relates to an arc-extinguishing paste for surface mount miniature fuse with breaking capacity above 250VAC / 100A, in particular to an arc-extinguishing paste using borosilicate double modified thermoplastic phenolic resin as a matrix, and the Preparation.

Background technique

The fuse is mainly composed of a melt and an insulator that supports or protects the melt. A metal wire or sheet electrode made of a metal material or paste with a lower melting point is used as the melt, which is connected in series in the protected circuit. When the equipment in the circuit is overloaded or malfunctions, the melt is melted instantaneously due to heat, thereby cutting off the circuit to achieve the purpose of protecting the circuit or equipment. With the development of miniaturization of fuses, the breaking safety of melts has gradually become a key factor to be considered when applying high voltage and high current. At the moment when the fault current is too large or the short circuit is disconnected, a powerful arc will be generated on the melt. If there is no material to extinguish this arc near the melt, the fuse will burn or there is a risk of explosion. Other valuable components in the circuit may even cause fire due to arc ignition and endanger personal safety.

CN102122595A discloses an arc extinguishing agent for a fuse. The arc extinguishing agent is added with a chloride salt, such as sodium chloride, potassium chloride, calcium chloride, barium chloride, etc., in a traditional quartz sand arc extinguishing material. Quartz sand can absorb the heat generated by the arc in an instant, and the chloride ions decomposed at high temperature can neutralize the ions generated by the arc, to prevent the ions generated by the arc from being drawn in the arc under high temperature conditions, thus playing a good arc extinguishing effect. However, because surface mount miniature fuses have halogen-free requirements, and halogen salts have strong hygroscopic properties, which has a great influence on the reliability of metal melts during long-term use, so this improved application range has a very high Big restrictions. Patent FR2927465A1, US8089023B2, CA101503540A, etc. disclose a circuit breaker case made of an arc-extinguishing resin processing product with excellent arc-extinguishing performance, heat resistance, pressure resistance and moldability, including polyolefin resin, There are three parts of crosslinking agent and metal hydroxide. Patent US2008237194A1 and CN101615525A also disclose a bushing or liner for fuse made of arc extinguishing material containing metal hydroxide or melamine and adhesive. When the object is in contact with the arc, water vapor is generated to extinguish the arc. The residue formed by the remaining solid composition does not reduce the dielectric strength of the composition. However, although such an arc extinguishing material has relatively high arc extinguishing performance, it is usually molded, Extruded into a fuse shell, it is difficult to make a slurry form and applied to surface mount miniature fuse. CN202977346U discloses a high-pressure resistant surface-mounting tubular fuse, which fills the silica gel layer around the melt in the insulating tube, uses the high insulation and high voltage breakdown capability of the silica gel to extinguish the arc, and uses the elasticity of the silica gel itself To absorb the energy generated in the melt fusing process, however, in actual operation, this structure loses its expected effect when the rated breaking capacity of the fuse exceeds 250VAC / 50A.

In addition to generating a large amount of thermal energy during the breaking process of the melt, two types of pressure will also accompany it: an explosion pressure in the form of a pulse at the instant when the melt gasification starts, and an arc pressure during the entire arc burning period. Conventional arc extinguishing materials can generally be subjected to physical and chemical changes such as pyrolysis, melting, evaporation, sublimation and erosion under the action of high-temperature heat flow, causing mass consumption on the surface of the material to remove heat, thereby reducing melt breakage The heat energy generated by the time. However, due to the existence of high temperature, conventional arc extinguishing materials such as quartz sand, silica gel, thermosetting resin, glass coating, etc. often do not have the elastic buffering ability to the explosion pressure. High, so it is easy to cause the failure of the fuse to break when the arc continues.

Summary of the invention

Object of the invention: In view of the above problems, the present invention provides an arc extinguishing slurry, which can extinguish the arc generated in the melt breaking process very effectively, has the heat resistance that can withstand the temperature rise in the process, and also has the ability to withstand the The pressure resistance of internal pressure shocks during the process.

Another object of the present invention is to provide a method for preparing such an arc-extinguishing slurry, which has obvious advantages such as simple process, high production efficiency, and low manufacturing cost.

Technical solution: In order to achieve the above-mentioned objectives, the arc-extinguishing slurry provided by the present invention may adopt the following technical solution.

An arc extinguishing slurry for fuse, the components of the arc extinguishing slurry include borosilicate double modified thermoplastic phenolic resin, modified hydroxide, microencapsulated red phosphorus, organic solvent, hexamethylenetetramine; The weight percent composition of the components is: borosilicate double modified thermoplastic phenolic resin 10% to 35%, modified magnesium hydroxide 20% to 65%, microencapsulated red phosphorus 1% to 5%, organic solvent 5% to 40 %, Hexamethylenetetramine 0.6% ~ 4%.

Beneficial effect: The arc extinguishing slurry in the present invention uses borosilicate double modified thermoplastic phenolic resin, which can improve the electrical insulation, heat resistance, ablation resistance, instantaneous high temperature resistance and flame retardant properties of the resin. The slurry also has stronger mechanical properties after solidification around the melt. In addition, the modified hydroxide and microencapsulated red phosphorus flame retardant added to the arc extinguishing slurry further improve the flame retardant performance of the borosilicate double modified phenolic resin, so that the arc extinguishing slurry can be used at 250VAC / When the high voltage and large current above 100A are disconnected. The arc-extinguishing paste of the present invention has low production cost, is halogen-free and environmentally friendly, and is suitable as a filling and printing paste for currently common surface mount miniature fuses.

Further, the modified hydroxide is a nano-magnesium hydroxide powder modified with one of a silane coupling agent, an organic silicon, and stearic acid, and the particle size of the nano-magnesium hydroxide powder is 3000-10000 mesh; or , The modified hydroxide is aluminum hydroxide, borax, zinc borate, melamine cyanurate. The role of the magnesium hydroxide powder is to thermally decompose at high temperature of the arc to absorb the heat generated by the arc, and at the same time release a lot of water to dilute the oxygen around the melt, and the activated magnesium oxide generated by the decomposition is adsorbed on the surface of the melt It further prevents the combustion from proceeding, so that the arc can be extinguished quickly. The microencapsulated red phosphorus can absorb the moisture decomposed during the combustion of magnesium hydroxide to generate phosphoric acid, polymetaphosphoric acid, etc., covering the surface of the phenolic resin, dehydrating and carbonizing the resin surface, and forming a liquid film layer with a certain thickness. Blocks the diffusion of oxygen and heat, thereby enhancing the flame retardant effect and ensuring the ability to break safely.

The organic solvent is at least one of ethylene glycol, dimethylformamide, dimethylacetamide, methylpyrrolidone, and dipropylene glycol monomethyl ether.

The method for preparing the arc-extinguishing slurry provided by the present invention may adopt the following technical solutions, including the following steps:

(1) Weigh the phenolic resin needed in the formula according to the solid content of the borosilicate double modified thermoplastic phenolic resin solution, add organic solvent in proportion, and stir for 0.5h to 1h;

(2) Weigh the modified hydroxide, microencapsulated red phosphorus, and hexamethylenetetramine according to the formula, add it to the solution obtained in step (1), stir and mix evenly, to obtain the arc extinguishing slurry.

Before step (1), the borosilicate double-modified thermoplastic phenolic resin is manufactured first. The preparation method of the borosilicate double-modified thermoplastic phenolic resin includes the following steps:

(a) Mix phenol and formaldehyde at a molar ratio of 1: 0.4 ～ 1.2, heat to 40 ℃ ～ 50 ℃, stir for 0.5h ～ 2h, then add an acid solution with phenol mole fraction of 0.02% ～ 1%, and continue stirring And slowly increase the temperature, control the temperature of the reaction solution to 70 ℃ ~ 90 ℃, the reaction 2h ~ 6h;

(b) Adding 0.1% to 5% of phenol molar fraction to the reaction solution, warming to 90 ° C to 110 ° C, and reacting for 2h to 8h;

(c) Continue to add silane coupling agent or organic silicon solution, which accounts for 1% to 30% of the phenol mole fraction, and continue the reaction for 2h to 12h;

(d) Add alkaline solution to adjust the pH of the reaction solution to 6 ~ 7.5, then add organic solvent for extraction and separation, and remove the water layer;

(e) After evacuating and heating to remove the solvent, and then adding an organic solvent to dissolve, the borosilicate double-modified thermoplastic phenolic resin solution is obtained.

Further, the acid solution in the preparation step (a) of the borosilicate double-modified thermoplastic phenolic resin refers to one of hydrochloric acid, nitric acid, oxalic acid, and acetic acid; the alkaline solution in the step (d) Refers to one of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate.

Further, the silane coupling agent in the preparation step (c) of the borosilicate double modified thermoplastic phenolic resin is a type of silane having an organic functional group, and is one of KH550, KH560, KH570, and KH792.

Further, the organic solvent for extracting the phenolic resin in the preparation step (d) of the borosilicate double-modified thermoplastic phenolic resin is one of toluene, xylene, ethyl acetate, and butyl acetate; the step (e ) The organic solvent used to dissolve the phenolic resin is one of ethylene glycol, dimethylformamide, dimethylacetamide, methylpyrrolidone, and dipropylene glycol monomethyl ether.

Further, in the preparation step (e) of the borosilicate double modified thermoplastic phenolic resin, the temperature of heating and vacuum desolvation is 100 ° C to 120 ° C.

Beneficial effect: The above preparation method has the advantages of simple process, high production efficiency and low manufacturing cost.

detailed description

The present invention will be described in detail below with reference to specific embodiments.

The arc-extinguishing slurry provided in the present invention is obtained from the following raw materials by weight ratio: borosilicate double-modified thermoplastic phenolic resin 10% -35%, modified magnesium hydroxide 20% -65%, microencapsulated red phosphorus 1 % To 5%, organic solvent 5% to 40%, hexamethylenetetramine 0.6% to 4%.

And, the preparation method of the present invention includes two steps of preparing a borosilicate double-modified thermoplastic phenolic resin and using the phenolic resin to prepare an arc-extinguishing slurry. The following further describes the above arc-extinguishing slurry and preparation method through several embodiments.

Example 1

First mix 1mol of phenol and 0.4mol of formaldehyde, heat to 40 ℃, stir for 0.5h, then add 0.0002mol of 1mol / L hydrochloric acid, and heat to 80 ℃, stir for 2h; add 0.005mol of boric acid to the reaction solution, and warm up to Stir at 100 ℃ for 2h; then add 0.1mol of silane coupling agent, keep the temperature at 100 ℃ and stir for 5h; add ammonia to adjust the pH of the solution to about 7.0, extract with ethyl acetate, and remove the separated water layer; Vacuum desolvation was carried out at 110 ° C for 1 hour; finally, ethylene glycol was added to dissolve the resin, and a borosilicate double-modified thermoplastic phenolic resin solution with a solid content of about 60% was obtained.

Take 100g of the phenolic resin solution obtained above, add 30g of ethylene glycol for dilution, and stir for 0.5h; weigh 180g of silane coupling agent modified magnesium hydroxide, 6g of microencapsulated red phosphorus, 3g of hexamethylenetetramine After stirring for 2h, the arc-extinguishing slurry for the high breaking capacity surface mount micro fuse according to the present invention can be obtained.

The obtained arc-extinguishing paste was adjusted to a viscosity of 40 Pa · s to 100 Pa · s using ethylene glycol, and the arc-extinguishing paste was printed on a design rated current of 2A and a size specification of 6.1 mm * 2.5 mm through a thick film printing process. The fuse link above the surface of the alumina ceramic substrate serves as an arc-extinguishing coating and protective layer. After the resin is cured, the required fuse product is obtained.

Conduct a 250VAC / 100A breaking capacity test on the 10pcs fuse product. After the breaking test, the product mark is clear, the protective layer has no obvious cracks, and there is no continuous arc ignition.

Example 2

Mix 1mol of phenol and 0.8mol of formaldehyde, heat to 50 ℃, stir for 1h, then add 0.003mol of 1mol / L oxalic acid, and heat to 90 ℃, stir for 4h; add 0.02mol of boric acid to the reaction solution and heat up to Stir at 100 ° C for 5h, then continue to add 0.15mol of silane coupling agent to the reaction solution, and stir for another 8h; after adding sodium hydroxide to adjust the pH of the solution to about 7.0, extract with toluene and separate the water layer at 110 ° C Vacuum desolvation was carried out for 1.5 hours, and finally dipropylene glycol monomethyl ether was added to dissolve the resin to obtain a borosilicate double modified thermoplastic phenolic resin solution with a solid content of about 60%.

Take 100g of the phenolic resin solution obtained above, add 50g of dipropylene glycol monomethyl ether for dilution, and stir for 0.5h; then weigh 260g of silicone modified magnesium hydroxide, 10g of microencapsulated red phosphorus, and 10g of hexamethylenetetramine , Stir for 3h to obtain the arc-extinguishing slurry for the high breaking capacity surface mount micro fuse of the present invention.

For a ceramic tube fuse with a rated current of 2A and a size of 6.1mm * 2.5mm * 2.5mm, a square opening of 0.3mm * 0.3mm is formed in the middle of the side wall of the side of the tube wall. Adjust the viscosity of propylene glycol monomethyl ether to 1Pa · s ～ 5Pa · s, place the fuse product in the container containing the arc-extinguishing slurry, and evacuate the container for 15min, so that the arc-extinguishing slurry is potted inside the tube shell To obtain a fuse product filled with arc-extinguishing slurry.

Carry out 350VAC / 100A breaking capacity test on the fuse products obtained by 10pcs. After the breaking test, the product mark is clear, the ceramic tube has no obvious cracking, and there is no continuous arc ignition.

Example 3

Mix 1mol of phenol and 1.2mol of formaldehyde, heat to 50 ℃, stir for 2h, then add 0.01mol of 1mol / L acetic acid, and heat to 90 ℃, stir for 6h; add 0.05mol of boric acid to the reaction solution and raise the temperature to 110 ℃, stirring for 8h, then continue to add 0.3mol of silane coupling agent to the reaction solution, and stir for another 12h; after adding potassium hydroxide to adjust the pH value of the solution to about 7.0, extract with butyl acetate, and separate the water layer, and then Vacuum desolvation was carried out at 110 ° C for 2 hours, and finally dimethylacetamide was added to dissolve the resin to obtain a borosilicate double-modified thermoplastic phenolic resin solution with a solid content of about 60%.

Take 100g of the phenolic resin solution obtained above, add 60g of dimethylacetamide for dilution, and stir for 0.5h; then weigh 200g of silicone-modified magnesium hydroxide, 12g of microencapsulated red phosphorus, and 8g of hexamethylenetetramine , Stir for 3h to obtain the arc-extinguishing slurry for the high breaking capacity surface mount micro fuse of the present invention.

The fuse product filled with the arc-extinguishing slurry was obtained and tested for breaking capacity according to the method described in Example 2. The results showed that the fuse product filled with this arc-extinguishing slurry also met the breaking conditions of 350VAC / 100A.

The phenolic resin can also be replaced by a modified thermosetting phenolic resin, which has little effect on the performance of the arc-extinguishing slurry.

There are many methods and ways for the present invention to specifically implement the technical solution, and the above are only preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principles of the present invention, several improvements can be made, and these improvements should also be regarded as the scope of protection of the present invention. The components that are not clear in this embodiment can be implemented with existing technology.

Claims (10)

1. An arc-extinguishing slurry for fuses, characterized in that the components of the arc-extinguishing slurry include borosilicate double modified thermoplastic phenolic resin, modified hydroxide, microencapsulated red phosphorus, organic solvent, hexamethylene Tetraamine; the weight percent composition of the above components is: borosilicate double modified thermoplastic phenolic resin 10% to 35%, modified magnesium hydroxide 20% to 65%, microencapsulated red phosphorus 1% to 5%, organic solvent 5% -40%, hexamethylenetetramine 0.6% -4%.
2. The arc-extinguishing slurry according to claim 1, characterized in that the modified hydroxide is a nano-magnesium hydroxide powder modified by one of a silane coupling agent, silicone, and stearic acid, nano The particle size of magnesium hydroxide powder is 3000 ～ 10000 mesh;
3. The arc-extinguishing slurry according to claim 1, wherein the modified hydroxide is aluminum hydroxide, borax, zinc borate, melamine cyanurate.
4. The arc extinguishing slurry according to claim 1, wherein the organic solvent is at least one of ethylene glycol, dimethylformamide, dimethylacetamide, methylpyrrolidone, and dipropylene glycol monomethyl ether Species.
5. A method for preparing an arc-extinguishing slurry according to any one of claims 1 to 5, characterized in that it includes the following steps:

   (1) Weigh the phenolic resin needed in the formula according to the solid content of the borosilicate double modified thermoplastic phenolic resin solution, add organic solvent in proportion, and stir for 0.5h to 1h;

   (2) Weigh the modified hydroxide, microencapsulated red phosphorus, and hexamethylenetetramine according to the formula, add it to the solution obtained in step (1), stir and mix evenly, to obtain the arc extinguishing slurry.
6. The preparation method according to claim 5, characterized in that prior to step (1), a borosilicate double-modified thermoplastic phenolic resin is manufactured. The preparation method of the borosilicate double-modified thermoplastic phenolic resin includes the following steps:

   (a) Mix phenol and formaldehyde at a molar ratio of 1: 0.4 ～ 1.2, heat to 40 ℃ ～ 50 ℃, stir for 0.5h ～ 2h, then add an acid solution with phenol mole fraction of 0.02% ～ 1%, and continue stirring And slowly increase the temperature, control the temperature of the reaction solution to 70 ℃ ~ 90 ℃, the reaction 2h ~ 6h;

   (b) Adding 0.1% to 5% of phenol molar fraction to the reaction solution, warming to 90 ° C to 110 ° C, and reacting for 2h to 8h;

   (c) Continue to add silane coupling agent or organic silicon solution, which accounts for 1% to 30% of the phenol mole fraction, and continue the reaction for 2h to 12h;

   (d) Add alkaline solution to adjust the pH of the reaction solution to 6 ~ 7.5, then add organic solvent for extraction and separation, and remove the water layer;

   (e) After evacuating and heating to remove the solvent, and then adding an organic solvent to dissolve, the borosilicate double-modified thermoplastic phenolic resin solution is obtained.
7. The preparation method according to claim 6, wherein the acid solution in the preparation step (a) of the borosilicate double-modified thermoplastic phenolic resin refers to one of hydrochloric acid, nitric acid, oxalic acid, and acetic acid ; The alkaline solution in step (d) refers to one of sodium hydroxide, potassium hydroxide, ammonia, and sodium carbonate.
8. The preparation method according to claim 6, characterized in that: the silane coupling agent in the preparation step (c) of the borosilicate double-modified thermoplastic phenolic resin is a type of silane having an organic functional group, and is KH550, KH560, One of KH570 and KH792.
9. The preparation method according to claim 6, wherein the organic solvent for extracting the phenolic resin in the preparation step (d) of the borosilicate double modified thermoplastic phenolic resin is toluene, xylene, ethyl acetate, butyl acetate One of the esters; the organic solvent used to dissolve the phenolic resin in the step (e) is one of ethylene glycol, dimethylformamide, dimethylacetamide, methylpyrrolidone, and dipropylene glycol monomethyl ether .
10. The preparation method according to claim 9, wherein the temperature of heating and vacuum desolvation in the preparation step (e) of the borosilicate double-modified thermoplastic phenolic resin is 100 ° C to 120 ° C.