Thread locking grease and preparation method thereof

Abstract

The invention belongs to the technical field of adhesives. The invention relates to thread locking grease, in particular to thread locking grease and a preparation method thereof. The product provided by the invention comprises the following raw materials in parts by weight: 80-90 parts of base oil, 10-15 parts of an organic bentonite thickening agent and 20-25 parts of an anaerobic adhesive, wherein the anaerobic adhesive is composed of an anaerobic monomer, an initiator and an accelerant. When the product is prepared, the base oil is divided into two parts, one part of the base oil is mixed with the organic bentonite thickening agent, the mixture is heated and stirred to react and cooled, and the base grease is obtained; in an inert atmosphere, mixing the other part of the base oil, the anaerobic monomer and the initiator, and uniformly stirring under a low-temperature condition to obtain anaerobic premixed rubber; the preparation method comprises the following steps: stirring, mixing and homogenizing the base grease and the anaerobic premixed glue under a vacuum condition, then adding the accelerant, continuously stirring uniformly, degassing, and discharging to obtain the thread locking grease.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology. More specifically, it relates to a thread-locking grease and its preparation method. Background Technology

[0002] Threaded fasteners (such as bolts, nuts, and screws) are widely used in industries such as machinery, automobiles, aerospace, electronics, and home appliances. The reliability of their connections directly affects the safety and stability of the entire equipment or structure.

[0003] To overcome the shortcomings of traditional mechanical anti-loosening methods, chemical locking technology has emerged and gained widespread application. Among them, threadlocking agents (also known as anaerobic adhesives) are currently the mainstream products on the market. These products cure under conditions of oxygen deficiency and contact with metal ions, firmly bonding the threaded parts together and exhibiting excellent anti-loosening, sealing, and rust-preventing properties. However, threadlocking agents also have some inherent limitations: anaerobic adhesives are mostly low-viscosity liquids, which are prone to flowing when applied to inclined or vertical surfaces, contaminating non-target areas, and the filling effect on the bottom threads of blind holes is difficult to guarantee; their curing efficiency is highly dependent on the catalytic activity of metal ions (poor effect on inert surfaces such as stainless steel and galvanized parts), the size of the gap (too large or too small a gap makes curing difficult), and the ambient temperature (curing is slow at low temperatures).

[0004] Compared to liquid locking agents, grease-based locking materials exhibit unique advantages. They are typically composed of thickeners, base oils, and functional additives (such as solid fillers and rust inhibitors), and are characterized by non-dripping properties, ease of application, and broad substrate compatibility.

[0005] However, existing threadlocking greases still have room for improvement: for example, their locking ability is weak, most products rely solely on physical action to prevent loosening, and they lack chemical bonding effects similar to anaerobic adhesives, thus limiting their ability to resist loosening under extreme impact loads. Summary of the Invention

[0006] The technical problem to be solved by this invention is that traditional thread-locking grease products have weak locking ability and cannot effectively guarantee the product's anti-loosening ability. This invention provides a thread-locking grease and its preparation method.

[0007] The purpose of this invention is to provide a thread-locking grease.

[0008] Another object of the present invention is to provide a method for preparing thread-locking grease.

[0009] The above-mentioned objective of this invention is achieved through the following technical solution:

[0010] A threadlocking grease, comprising the following raw materials in parts by weight:

[0011] 80-90 parts base oil, 10-15 parts organic bentonite thickener, 20-25 parts anaerobic binder;

[0012] The anaerobic adhesive is composed of anaerobic monomers, initiators, and accelerators.

[0013] The mass ratio of the anaerobic monomer, initiator and accelerator is (15-20):(1-4):(0.5-2).

[0014] The beneficial effects of the above technical solution are as follows:

[0015] The above technical solution utilizes base oil and organic bentonite thickener to form a stable grease-like structure, providing excellent physical locking force (through thixotropy and adhesion). Simultaneously, it incorporates up to 20-25 parts of anaerobic adhesive, ensuring strong chemical adhesion in the oxygen-deficient environment of thread engagement. This dual "physical + chemical" mechanism provides more reliable and durable vibration and loosening resistance compared to single-mechanism locking products.

[0016] In addition, by limiting the mass ratio of monomers, initiators and accelerators in the anaerobic component, this ratio ensures that the initiator and accelerator can efficiently initiate monomer polymerization, resulting in fast and thorough curing. At the same time, it avoids the problem of decreased product stability caused by slow decomposition of excessive initiator or accelerator during storage, thereby extending the product shelf life.

[0017] Furthermore, the base oil is selected from one or a mixture of several of polyalphaolefin synthetic oils, ester oils, and polyether oils.

[0018] The base oils are selected from polyalphaolefin (PAO), ester oils, or polyether oils, all of which are synthetic base oils. They possess high flash points, low volatility, excellent viscosity-temperature properties, and thermal oxidative stability. This means that this threadlocker grease maintains stable performance over a wider temperature range (e.g., -40°C to 150°C or even higher), without thinning or solidifying at high temperatures or at low temperatures, making it suitable for harsh working environments.

[0019] Furthermore, the D50 of the organic bentonite is 25-30 μm, and the D90 of the organic bentonite is ≤50 μm.

[0020] By limiting the specifications of organic bentonite, a more stable and uniform three-dimensional network structure is formed, effectively preventing the sedimentation and separation of solid fillers and anaerobic components, and greatly improving the product's storage stability. At the same time, it endows the product with excellent thixotropic properties: it thins under external force during construction, making it easy to spread, and immediately returns to a thick state after construction, exhibiting excellent anti-flow and anti-sagging properties, making it particularly suitable for thread locking on top or vertical surfaces; it can better wrap and fix functional components, ensuring consistent performance.

[0021] Furthermore, the anaerobic monomer is selected from one or more of 1,4-butanediol dimethacrylate, triethylene glycol dimethacrylate, and polyethylene glycol dimethacrylate.

[0022] Furthermore, the initiator is selected from either cumene hydroperoxide or tert-butyl hydroperoxide.

[0023] Furthermore, the accelerator is a salt formed by the reaction of an amine accelerator or an acylhydrazine accelerator with an acidic substance.

[0024] Furthermore, it also includes 4-6% TPE resin by weight of base oil;

[0025] The TPE resin is selected from either hydrogenated styrene-butadiene-styrene block copolymer or hydrogenated styrene-isoprene-styrene block copolymer.

[0026] The beneficial effects of the above technical solution are as follows:

[0027] By adding TPE resin, which acts as a highly efficient tackifier, the grease adheres firmly to the bolt surface like "playdough," preventing it from falling off before installation and thus enhancing initial adhesion. Before anaerobic curing, the viscoelastic film formed by TPE effectively seals the thread gaps, preventing leakage. TPE dispersed in the cured polymer network acts as a toughening agent, preventing the pure acrylic ester adhesive layer from becoming too brittle and improving impact and peel resistance. The hydrogenated SEBS / SEPS has high chemical inertness and will not interfere with the anaerobic free radical polymerization reaction, ensuring that the curing performance is not affected.

[0028] A method for preparing thread-locking grease, the specific preparation steps of which include:

[0029] Preparation of base lipids:

[0030] The base oil is divided into two parts. One part of the base oil is mixed with an organic bentonite thickener, heated and stirred to react, and then cooled to obtain the base grease.

[0031] Preparation of anaerobic premixed adhesives:

[0032] In an inert atmosphere, another portion of the base oil, anaerobic monomer and initiator are mixed and stirred evenly under low temperature conditions to obtain anaerobic premixed adhesive.

[0033] Preparation of thread-locking grease:

[0034] The base grease and anaerobic premixed adhesive are stirred and homogenized under vacuum conditions. Then, an accelerator is added, and the mixture is stirred until homogeneous. After degassing and discharge, the thread-locking grease is obtained.

[0035] Furthermore, the low-temperature condition is a temperature ≤ 40℃.

[0036] Furthermore, the specific preparation steps also include:

[0037] Preparation of base lipids:

[0038] The base oil is divided into two parts. One part of the base oil is mixed with TPE resin and left to stand at room temperature for more than 48 hours. Then it is heated and stirred evenly. Then an organic bentonite thickener is added, mixed, heated and stirred to react, and cooled to obtain the base grease.

[0039] Preparation of anaerobic premixed adhesives:

[0040] In an inert atmosphere, another portion of the base oil, anaerobic monomer and initiator are mixed and stirred evenly under low temperature conditions to obtain anaerobic premixed adhesive.

[0041] Preparation of thread-locking grease:

[0042] The base grease and anaerobic premixed adhesive are stirred and homogenized under vacuum conditions. Then, an accelerator is added, and the mixture is stirred until homogeneous. After degassing and discharge, the thread-locking grease is obtained.

[0043] The beneficial effects of the above technical solution are as follows:

[0044] The above technical solution involves mixing the base oil and TPE resin and then allowing them to stand at room temperature for an extended period of time. This step is crucial to ensuring that the TPE resin is fully swollen in the base oil and is a prerequisite for subsequent uniform dispersion. It directly affects the thickening effect and appearance uniformity of the final product.

[0045] Furthermore, by preparing TPE pregel first and then reacting it with the thickener, the feeding sequence ensures that TPE and organic bentonite each form the optimal network structure and intertwine with each other, avoiding structural damage or component aggregation that may be caused by improper feeding sequence, thereby maximizing the thickening and toughening effect of TPE and the thickening effect of bentonite. Detailed Implementation

[0046] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0047] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0048] Example 1

[0049] Raw material preparation:

[0050] By weight, take 80 parts base oil, 10 parts organic bentonite thickener, 20 parts anaerobic binder, and 4% TPE resin by weight of base oil.

[0051] The anaerobic adhesive is composed of anaerobic monomers, initiators, and accelerators.

[0052] The mass ratio of the anaerobic monomer, initiator, and accelerator is 15:1:0.5;

[0053] The base oil is selected from polyalphaolefin synthetic oil, specifically PAO 6 product manufactured by ExxonMobil;

[0054] The organic bentonite has a D50 of 25 μm and a D90 of 45 μm.

[0055] The anaerobic monomer is selected from 1,4-butanediol dimethacrylate;

[0056] The initiator is selected from cumene hydroperoxide;

[0057] The accelerator is an amine accelerator, specifically, Mcure-accelerator D-60 produced by Shanghai Jiushicheng Chemical Technology Co., Ltd.

[0058] The TPE resin is selected from hydrogenated styrene-butadiene-styrene block copolymer and is produced by Kraton Polymers.

[0059] Preparation of base lipids:

[0060] According to the mass ratio, the base oil is divided into two equal parts. One part of the base oil is mixed with TPE resin and left to stand at room temperature for 49 hours. Then, it is heated and stirred for 2 hours at a temperature of 60°C and a stirring speed of 300 r / min. Then, organic bentonite thickener is added, mixed, and heated and stirred for another 2 hours. After naturally cooling to room temperature, the base grease is obtained.

[0061] Preparation of anaerobic premixed adhesives:

[0062] In an inert atmosphere, another portion of the base oil, anaerobic monomer and initiator are mixed and stirred for 20 minutes at a temperature of 38°C and a stirring speed of 200 r / min to obtain an anaerobic premixed gel.

[0063] Preparation of thread-locking grease:

[0064] The base grease and anaerobic premixed adhesive were stirred and mixed under vacuum at a speed of 300 r / min for 40 min. Then, an accelerator was added, and stirring was continued for another 20 min. After degassing, the product was discharged to obtain the thread-locking grease.

[0065] Example 2

[0066] Raw material preparation:

[0067] By weight, take 85 parts base oil, 12 parts organic bentonite thickener, 22 parts anaerobic binder, and 5% TPE resin by weight of base oil.

[0068] The anaerobic adhesive is composed of anaerobic monomers, initiators, and accelerators.

[0069] The mass ratio of the anaerobic monomer, initiator and accelerator is 18:2:1;

[0070] The base oil is selected from polyalphaolefin synthetic oil, specifically PAO 6 product manufactured by ExxonMobil;

[0071] The organic bentonite has a D50 of 28 μm and a D90 of 48 μm.

[0072] The anaerobic monomer is selected from triethylene glycol dimethacrylate;

[0073] The initiator is selected from tert-butyl hydroperoxide;

[0074] The accelerator is an amine accelerator, specifically, Mcure-accelerator D-60 produced by Shanghai Jiushicheng Chemical Technology Co., Ltd.

[0075] The TPE resin is selected from hydrogenated styrene-isoprene-styrene block copolymer and is produced by Kraton Polymers.

[0076] Preparation of base lipids:

[0077] According to the mass ratio, the base oil is divided into two equal parts. One part of the base oil is mixed with TPE resin and left to stand at room temperature for 50 hours. Then, it is heated and stirred for 2.3 hours at a temperature of 60°C and a stirring speed of 360 r / min. Then, organic bentonite thickener is added, mixed, and heated and stirred for another 2.5 hours. After naturally cooling to room temperature, the base grease is obtained.

[0078] Preparation of anaerobic premixed adhesives:

[0079] In an inert atmosphere, another portion of the base oil, anaerobic monomer and initiator are mixed and stirred for 25 minutes at a temperature of 36°C and a stirring speed of 220 r / min to obtain an anaerobic premixed gel.

[0080] Preparation of thread-locking grease:

[0081] The base grease and anaerobic premixed adhesive were stirred and mixed under vacuum at a speed of 350 r / min for 50 min. Then, an accelerator was added, and stirring was continued for 20 min. After degassing, the product was discharged to obtain the thread-locking grease.

[0082] Example 3

[0083] Raw material preparation:

[0084] By weight, take 90 parts base oil, 15 parts organic bentonite thickener, 25 parts anaerobic binder, and 6% TPE resin by weight of base oil.

[0085] The anaerobic adhesive is composed of anaerobic monomers, initiators, and accelerators.

[0086] The mass ratio of the anaerobic monomer, initiator and accelerator is 20:4:2;

[0087] The base oil is selected from polyalphaolefin synthetic oil, specifically PAO 6 product manufactured by ExxonMobil;

[0088] The organic bentonite has a D50 of 30 μm and a D90 of 50 μm.

[0089] The anaerobic monomer is selected from polyethylene glycol dimethacrylate;

[0090] The initiator is selected from cumene hydroperoxide;

[0091] The accelerator is an amine accelerator, specifically, Mcure-accelerator D-60 produced by Shanghai Jiushicheng Chemical Technology Co., Ltd.

[0092] The TPE resin is selected from hydrogenated styrene-isoprene-styrene block copolymer and is produced by Kraton Polymers.

[0093] Preparation of base lipids:

[0094] According to the mass ratio, the base oil is divided into two equal parts. One part of the base oil is mixed with TPE resin and left to stand at room temperature for 52 hours. Then, it is heated and stirred for 3 hours at a temperature of 60°C and a stirring speed of 400 r / min. Then, organic bentonite thickener is added, mixed, and heated and stirred for another 3 hours. After naturally cooling to room temperature, the base grease is obtained.

[0095] Preparation of anaerobic premixed adhesives:

[0096] In an inert atmosphere, another portion of the base oil, anaerobic monomer and initiator are mixed and stirred for 30 minutes at a temperature of 35°C and a stirring speed of 300 r / min to obtain an anaerobic premixed gel.

[0097] Preparation of thread-locking grease:

[0098] The base grease and anaerobic premixed adhesive were stirred and mixed under vacuum at a speed of 400 r / min for 60 min. Then, an accelerator was added, and stirring was continued for 20 min. After degassing, the product was discharged to obtain the thread-locking grease.

[0099] Example 4

[0100] The difference between this embodiment and Embodiment 1 is as follows:

[0101] No TPE resin was added, and all other conditions remained unchanged.

[0102] Example 5

[0103] The difference between this embodiment and Embodiment 1 is as follows:

[0104] The organic bentonite has a D50 of 25 μm and a D90 of 65 μm.

[0105] All other conditions remain unchanged.

[0106] Example 6

[0107] The difference between this embodiment and Embodiment 1 is as follows:

[0108] Preparation of base lipids:

[0109] According to the mass ratio, the base oil is divided into two equal parts. One part of the base oil is mixed with TPE resin and left to stand at room temperature for 40 hours. Then, it is heated and stirred for 2 hours at a temperature of 60°C and a stirring speed of 300 r / min. Then, organic bentonite thickener is added, mixed, and heated and stirred for another 2 hours. After naturally cooling to room temperature, the base grease is obtained.

[0110] All other conditions remain unchanged.

[0111] Comparative Example 1

[0112] The difference between this comparative example and Example 1 is as follows:

[0113] No anaerobic binder was added, and all other conditions remained unchanged.

[0114] The products obtained in the above embodiments and comparative examples were subjected to performance tests. The specific test methods and test results are shown below:

[0115] Sample preparation:

[0116] Standard high-strength internal hex bolts and nuts (M10x1.5) were selected, made of carbon steel (grade 8.8);

[0117] Thoroughly clean, degrease, and dry the specimen with a volatile solvent (acetone) to ensure there is no oil residue.

[0118] Apply the thread-locking grease to be tested evenly to the threads of the bolt (apply to the first 2 / 3 of the engaged section);

[0119] Manually screw the nut in until it is flush with the end face of the bolt, and then tighten the nut with a torque wrench at a constant assembly torque (25 N·m), and record this assembly torque value.

[0120] The assembled specimens were allowed to cure under constant temperature and humidity conditions (23±2℃, 50±5%RH) for 24 hours to obtain the sample to be tested.

[0121] Static evaluation:

[0122] The cured test specimen is firmly clamped in the fixture; using a calibrated torque tester, the nut is rotated at a constant and slow rate (5 rpm) to loosen it; the maximum torque value when the threaded connection first loosens is recorded, which is the "static failure torque". Detailed test results are shown in Table 1.

[0123] Disassembly torque assessment:

[0124] After completing the above destructive torque test, continue rotating the torque tester to completely unscrew the nut. Record the average torque required during the entire loosening process; this is the "removal torque." Detailed test results are shown in Table 1.

[0125] Table 1: Product Performance Evaluation Results

[0126] Static breaking torque / N·m Disassembly torque / N·m Example 1 52 45 Example 2 53 46 Example 3 55 47 Example 4 45 36 Example 5 47 34 Example 6 49 33 Comparative Example 1 35 21

[0127] As can be seen from the test results in Table 1, the product obtained by the present invention can achieve effective locking of threads.

[0128] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A thread-locking grease, characterized in that, The ingredients include the following parts by weight: 80-90 parts base oil, 10-15 parts organic bentonite thickener, 20-25 parts anaerobic binder; The anaerobic adhesive is composed of anaerobic monomers, initiators, and accelerators. The mass ratio of the anaerobic monomer, initiator and accelerator is (15-20):(1-4):(0.5-2).

2. The thread-locking grease according to claim 1, characterized in that, The base oil is selected from one or a mixture of several of polyalphaolefin synthetic oils, ester oils, and polyether oils.

3. The thread-locking grease according to claim 1, characterized in that, The organic bentonite has a D50 of 25-30 μm and a D90 of ≤50 μm.

4. The thread-locking grease according to claim 1, characterized in that, The anaerobic monomer is selected from one or more of 1,4-butanediol dimethacrylate, triethylene glycol dimethacrylate, and polyethylene glycol dimethacrylate.

5. The thread-locking grease according to claim 1, characterized in that, The initiator is selected from either cumene hydroperoxide or tert-butyl hydroperoxide.

6. The thread-locking grease according to claim 1, characterized in that, The accelerator is a salt formed by the reaction of an amine accelerator or an acylhydrazine accelerator with an acidic substance.

7. The thread-locking grease according to claim 1, characterized in that, It also includes TPE resin at 4-6% of the base oil mass; The TPE resin is selected from either hydrogenated styrene-butadiene-styrene block copolymer or hydrogenated styrene-isoprene-styrene block copolymer.

8. A method for preparing a thread-locking grease as described in any one of claims 1-7, characterized in that, The specific preparation steps include: Preparation of base lipids: The base oil is divided into two parts. One part of the base oil is mixed with an organic bentonite thickener, heated and stirred to react, and then cooled to obtain the base grease. Preparation of anaerobic premixed adhesives: In an inert atmosphere, another portion of the base oil, anaerobic monomer and initiator are mixed and stirred evenly under low temperature conditions to obtain anaerobic premixed adhesive. Preparation of thread-locking grease: The base grease and anaerobic premixed adhesive are stirred and homogenized under vacuum conditions. Then, an accelerator is added, and the mixture is stirred until homogeneous. After degassing and discharge, the thread-locking grease is obtained.

9. The method for preparing a thread-locking grease according to claim 8, characterized in that, The low-temperature condition is a temperature ≤ 40℃.

10. A method for preparing a thread-locking grease according to claim 8, characterized in that, The specific preparation steps also include: Preparation of base lipids: The base oil is divided into two parts. One part of the base oil is mixed with TPE resin and left to stand at room temperature for more than 48 hours. Then it is heated and stirred evenly. Then an organic bentonite thickener is added, mixed, heated and stirred to react, and cooled to obtain the base grease. Preparation of anaerobic premixed adhesives: In an inert atmosphere, another portion of the base oil, anaerobic monomer and initiator are mixed and stirred evenly under low temperature conditions to obtain anaerobic premixed adhesive. Preparation of thread-locking grease: The base grease and anaerobic premixed adhesive are stirred and homogenized under vacuum conditions. Then, an accelerator is added, and the mixture is stirred until homogeneous. After degassing and discharge, the thread-locking grease is obtained.