Alkali-free degumming agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of degumming agents, and discloses an alkali-free degumming agent and a preparation method and application thereof, and the alkali-free degumming agent comprises the following components by mass: 75-99% of glycerol; 0.5 to 24.5 percent of a surfactant; and 0.5 to 24.5 percent of a penetrating agent. According to the alkali-free degumming agent, a novel degumming agent with glycerol as a main body is neutral, the performance of the alkali-free degumming agent is stable, any adverse chemical reaction between the alkali-free degumming agent and neodymium iron boron materials is avoided, and the yield of workpieces is guaranteed; and by controlling the temperature and introducing the functional auxiliary agent, the degumming time is also remarkably shortened on the premise of ensuring a better degumming effect.

Description

Technical Field

[0001] The invention relates to the technical field of degumming agents, in particular to an alkali-free degumming agent and a preparation method and application thereof. Background Art

[0002] Neodymium iron boron (Nd2Fe14B) permanent magnet is the latest result of the development of rare earth permanent magnet materials. It is called "magnet king" due to its excellent magnetic properties. Neodymium iron boron is divided into sintered neodymium iron boron and bonded neodymium iron boron. Sintered neodymium iron boron permanent magnet material is widely used in electronics, power machinery, medical equipment, toys, packaging, hardware machinery, aerospace and other fields due to its excellent magnetic properties, such as permanent magnet motors, speakers, magnetic separators, computer disk drives, magnetic resonance imaging equipment and instruments, etc.

[0003] From sintered blanks to finished products, NdFeB materials need to go through multiple production processes such as cutting (multiple times), grinding (multiple times), chamfering, and electroplating. In the cutting process, in order to increase processing efficiency, the products are generally stacked and fixed with special magnetic glue (502 glue) before entering the subsequent processing. After the sintered NdFeB is fixed by bonding, the 502 glue used for bonding needs to be removed after machining, and then electroplating and magnetization are performed to become the final product.

[0004] The existing debonding process, since the large-scale industrial production of NdFeB in China until now, most of them use the method of heating with sodium hydroxide (NaOH) solution to remove the glue.

[0005] However, with the increasing market requirements for the quality of NdFeB electroplating products and the increasing environmental protection requirements, the defects of heating and degumming with sodium hydroxide solution are becoming more and more apparent, mainly manifested in the following four points: 1. Sodium hydroxide solution is highly alkaline and extremely corrosive to the surface of the product, which will seriously damage the surface state of the workpiece and ultimately reduce the yield rate of the finished product after electroplating; 2. In order to achieve the ideal degumming effect, it is usually necessary to extend the processing time, resulting in low efficiency; 3. With the improvement of national environmental protection standards, the treatment cost of highly alkaline sodium hydroxide waste liquid is increasing rapidly, and in the foreseeable future, it will face a complete ban in the magnetic material industry; 4. When sodium hydroxide aqueous solution is heated, it will not only cause chemical pollution to the environment, but also easily cause chemical burns to operators; 5. After degumming with sodium hydroxide aqueous solution, various waste rubber impurities are likely to remain on the surface of the workpiece, which must be cleaned twice before entering the next process, which will cause secondary water pollution. Summary of the invention

[0006] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides an alkali-free degumming agent and a preparation method and application thereof, which have the advantages of high yield rate, short degumming time and no pollution.

[0007] (II) Technical solution In order to achieve the above-mentioned purpose of high yield, short degumming time and no pollution, the present invention provides the following technical solution: an alkali-free degumming agent, characterized in that the degumming agent comprises the following components: Glycerol, surfactant, penetrant.

[0008] As a preferred technical solution of the present invention: The degumming agent comprises the following components in terms of mass percentage: Glycerol 75-99%; Surfactant 0.5-24.5%; Penetrant 0.5-24.5%.

[0009] As a preferred technical solution of the present invention: The degumming agent comprises the following components in terms of mass percentage: Glycerol 85-95%; Surfactant 5-15%; Penetrant 5-15%.

[0010] As a preferred technical solution of the present invention: the surfactant is an alkyl polyglycoside or an equivalent non-ionic surfactant thereof, including but not limited to fatty alcohol polyoxyethylene ether and sugar-based surfactant.

[0011] As a preferred technical solution of the present invention: the penetrant is sorbitan monooleate or its equivalent, including but not limited to glycerol monooleate or other fatty acid ester substances.

[0012] (III) Beneficial effects Compared with the prior art, the present invention provides an alkali-free degumming agent, which has the following beneficial effects: 1. This alkali-free degumming agent, a new type of degumming agent with propylene glycol as the main component, is neutral and has stable performance. It will not cause any adverse chemical reaction with the NdFeB material, thus ensuring the yield rate of the workpiece.

[0013] 2. This alkali-free degumming agent significantly shortens the degumming time while ensuring better degumming effect through temperature control and the introduction of functional additives.

[0014] 3. The raw materials of this alkali-free degumming agent are safe and harmless, and are infinitely soluble in water. It can be diluted and flushed with clean water at any time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a comparison diagram after degumming with sodium hydroxide solution (left picture) and after degumming according to the present invention (right picture). DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Example: See also Figure 1 , an alkali-free degumming agent, the degumming agent is composed of glycerol, a surfactant and a penetrant, according to the mass percentage, glycerol 75-99%, surfactant 0.5-24.5%, penetrant 0.5-24.5%, preferably, glycerol 85-95%, surfactant 5-15%, penetrant 5-15%; The surfactant is specifically selected from alkyl polyglycosides, and its equivalent non-ionic surfactants, such as fatty alcohol polyoxyethylene ethers and sugar-based surfactants, can also be used; The specific penetrant is sorbitan monooleate, and its equivalents, such as glycerol monooleate or other fatty acid esters, can also be used.

[0018] Glycerol is used as the main heat transfer medium. Its high boiling point and stability allow the degumming agent to remain liquid in the range of 150-290°C, providing stable thermal conductivity and avoiding local overheating or incomplete decomposition of 502 colloid at high temperatures. Through experimental comparison, the degumming efficiency of the degumming agent using glycerol is more than 30% higher than that of traditional water-based or oil-based heat transfer fluids. At the same time, it is non-corrosive to the surface of NdFeB, ensuring the good surface quality of NdFeB.

[0019] Alkyl polyglycoside is a nonionic surfactant that can reduce the interfacial tension on the surface of the colloid and promote the dispersion and stripping of 502 colloid. If no surfactant is added, higher temperature and longer time are required, and colloid residue is likely to be produced. At the same time, the good dispersibility of alkyl polyglycoside in propylene glycol can further enhance the permeability and interfacial wetting properties of the degumming agent, thereby accelerating the decomposition of 502 colloid.

[0020] The penetrant can significantly improve the penetration ability of the degumming agent, allowing the degumming agent to quickly penetrate between the colloid and the workpiece surface, further accelerating the decomposition and detachment of the colloid. By adding sorbitan monooleate, the degumming integrity is improved by more than 40%, avoiding the residual glue problem common in traditional processes and reducing subsequent cleaning steps.

[0021] In the present invention, propylene glycol, which is excellent in environmental protection, safety and stability, is used as the main heat-conducting medium, and a functional auxiliary agent compounded with a surfactant (alkyl polysaccharide) and a penetrant (sorbitan monooleate) which are also excellent in environmental protection is added to prepare a heat-conducting solution system with high thermal conductivity and high activity.

[0022] When used specifically, the heat-conducting solution is heated and stabilized within the 502 colloid decomposition range of 150-290°C. With the assistance of the functional additives, the 502 colloid is accelerated to decompose, thereby achieving rapid debonding of the NdFeB workpiece.

[0023] The sodium hydroxide solution used in traditional processes is highly alkaline and extremely corrosive to the surface of the product, which will seriously damage the surface condition of the workpiece and ultimately lead to a decrease in the yield rate of the finished product after electroplating. The new degumming agent based on propylene glycol is neutral and has stable performance. It will not undergo any adverse chemical reactions with the NdFeB material, thus ensuring the yield rate of the workpiece.

[0024] In order to achieve the ideal degumming effect, the traditional process usually requires extended processing time, resulting in low efficiency; the new degumming agent is specially designed for the decomposition of 502 colloid. Through temperature control and the introduction of functional additives, it can shorten the degumming time by more than half while ensuring better degumming effect.

[0025] After the sodium hydroxide solution is heated, it will not only cause chemical pollution to the environment, but also easily cause chemical burns to the skin and respiratory tract of the operator. At the same time, after the sodium hydroxide solution is degummed, various waste glue impurities are also likely to remain on the surface of the workpiece, which must be cleaned twice before entering the next process, and it will also cause secondary water pollution. The present invention effectively avoids the above problems.

[0026] In the present invention, the raw materials used in the degumming agent are the same products used in the pharmaceutical and food industries, which are safe and harmless, infinitely soluble in water, and can be diluted and flushed with clean water at any time.

[0027] The degumming agent of the present invention eliminates the influence of alkaline substances on the surface of NdFeB, increases the bonding rate of electroplating, and degummes by physical means. Glycerol is used as a heat-conducting medium to make the product absorb heat so that the glue is gasified when encountering high temperature, thereby achieving the degumming effect.

[0028] The present invention also provides a method for preparing an alkali-free degumming agent, the specific steps of which are: S1. Add glycerol into a stirring container as a base liquid; S2. Add surfactant and penetrant in sequence under stirring, maintaining uniform mixing; S3, heat the mixed solution to 40-60°C and stir until completely dispersed; S4, cooling to room temperature to obtain the alkali-free degumming agent.

[0029] The alkali-free degumming agent prepared by the present invention can be preferably used in the degumming of NdFeB materials. Specifically, during the degumming, the degumming temperature is 150-290°C.

[0030] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Alkali-free degumming agent, characterized in that: The degumming agent comprises the following components: Glycerol, surfactant, penetrant.

2. The alkali-free degumming agent according to claim 1, characterized in that: The degumming agent comprises the following components in terms of mass percentage: Glycerol 75-99%; Surfactant 0.5-24.5%; Penetrant 0.5-24.5%.

3. The alkali-free degumming agent according to claim 1, characterized in that: The degumming agent comprises the following components in terms of mass percentage: Glycerol 85-95%; Surfactant 5-15%; Penetrant 5-15%.

4. The alkali-free degumming agent according to any one of claims 1 to 3, characterized in that: The surfactant is an alkyl polyglycoside or an equivalent nonionic surfactant thereof, including but not limited to fatty alcohol polyoxyethylene ether and sugar-based surfactants.

5. The alkali-free degumming agent according to any one of claims 1 to 3, characterized in that: The osmotic agent is sorbitan monooleate or its equivalent, including but not limited to glycerol monooleate.

6. A method for preparing an alkali-free degumming agent, used for the alkali-free degumming agent as claimed in any one of claims 1 to 5, characterized in that: The preparation method is: The components are mixed and dispersed to obtain the degumming agent.

7. Use of the alkali-free degumming agent as claimed in any one of claims 1 to 5 in degumming of NdFeB materials.

8. The use according to claim 7, characterized in that: The degumming temperature is 150-290°C.

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