High-wear-resistance and corrosion-resistance diaphragm for diaphragm pump and preparation method of high-wear-resistance and corrosion-resistance diaphragm

Abstract

The invention discloses a high-wear-resistance and corrosion-resistance diaphragm for a diaphragm pump and a preparation method of the high-wear-resistance and corrosion-resistance diaphragm, and belongs to the technical field of parts for diaphragm pumps. The corrosion-resistant composite material comprises a corrosion-resistant layer and a reinforcing layer, and the corrosion-resistant layer and the reinforcing layer are bonded through a binder. Wherein the corrosion-resistant layer comprises 100 parts of polytetrafluoroethylene, 10-20 parts of methacrylate containing an epoxy group, 5-10 parts of a monomer containing a double bond and a phenol group, and 1-2 parts of an initiator; the reinforcing layer comprises 100 parts of nitrile rubber, 30-40 parts of methyl divinyl silicone rubber, 2-3 parts of a vulcanizing agent, 3-5 parts of an anti-aging agent and 0.1-0.4 part of an accelerant. One side of the corrosion-resistant layer of the diaphragm is in direct contact with fluid, so that the wear resistance, the corrosion resistance, the fatigue resistance and the flexing resistance of the diaphragm can be improved, and the service life of the diaphragm is prolonged.

Description

Technical Field

[0001] The present application relates to a highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump and a preparation method thereof, belonging to the technical field of components for diaphragm pumps. Background Art

[0002] The diaphragm pump is mainly composed of a pump body, a diaphragm, a driving mechanism, a valve, and suction and discharge pipes. The outer shell is usually made of metal or plastic. The diaphragm is the core component of the diaphragm pump. It divides the pump chamber into two sides, which are respectively connected to the liquid inlet and outlet. Under the action of the driving mechanism, it performs reciprocating motion to realize the suction and discharge of the fluid.

[0003] The most common diaphragm materials are generally made of elastic materials such as rubber (such as nitrile rubber) or polymers (such as polytetrafluoroethylene). Nitrile rubber has good oil resistance, wear resistance, and strength, but it only has limited corrosion resistance against weak acids, weak bases, and saline solutions. When transporting highly acidic or alkaline fluids, it will inevitably be corroded by the fluid, resulting in a decrease in its mechanical properties and an inability to provide a satisfactory sealing effect. Nitrile rubber also has poor water resistance, and water molecules can easily penetrate the rubber, making it unsuitable for transporting aqueous fluids alone.

[0004] In the "Development of a New Rubber-Plastic Composite Diaphragm," a new composite diaphragm is prepared by combining a polytetrafluoroethylene film with a rubber substrate. This is achieved by activating the polytetrafluoroethylene film and then co-vulcanizing it with the rubber substrate to produce a composite diaphragm with a complete appearance and good adhesion between the polytetrafluoroethylene film and the rubber substrate. However, polytetrafluoroethylene has the disadvantages of high creep and relatively low hardness. This makes the diaphragm susceptible to wear, cracking, or tearing during its reciprocating motion. This can affect the flow rate of fluid transmission, leading to damage to valve seals and wear of the valve core within the pump. In more severe cases, some areas may fall off, causing fluid leakage, impacting production safety and product quality. Furthermore, creep can occur, causing the diaphragm to deform, making it difficult to use for a long time.

[0005] Therefore, there is an urgent need for a diaphragm material that has both high wear resistance and high corrosion resistance for use in diaphragm pumps. Summary of the Invention

[0006] In order to solve the above problems, a highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump and a preparation method thereof are provided. The diaphragm includes a corrosion-resistant layer and a reinforcement layer. One side of the corrosion-resistant layer is in direct contact with the fluid. By adding methacrylate containing epoxy groups and monomer substances containing double bonds and phenol groups, the creep resistance and wear resistance of the polytetrafluoroethylene material can be improved, the deformation of the diaphragm can be reduced, and the high corrosion resistance of polytetrafluoroethylene can be maintained. At the same time, the reinforcement layer improves the fatigue resistance and flexibility resistance of the diaphragm, which can further increase the service life of the diaphragm.

[0007] According to one aspect of the present application, a highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump is provided, comprising a corrosion-resistant layer and a reinforcement layer, wherein the corrosion-resistant layer and the reinforcement layer are bonded together by an adhesive; wherein:

[0008] The corrosion-resistant layer comprises 100 parts of polytetrafluoroethylene, 10-20 parts of methacrylate containing epoxy groups, 5-10 parts of monomer containing double bonds and phenol groups, and 1-2 parts of initiator;

[0009] The reinforcing layer comprises 100 parts of nitrile rubber, 30-40 parts of methyl divinyl silicone rubber, 2-3 parts of vulcanizing agent, 3-5 parts of antioxidant and 0.1-0.4 parts of accelerator.

[0010] The epoxy group-containing methacrylate and the monomer containing a double bond and a phenol group contain epoxy groups and phenol groups, which can improve the compatibility with the epoxy resin adhesive, thereby improving the bonding performance of the corrosion-resistant layer and the reinforcement layer and extending the service life of the diaphragm material.

[0011] In addition, methacrylate containing epoxy groups and monomers containing double bonds and phenol groups can react under the action of initiators to obtain copolymers, which can improve the following properties of polytetrafluoroethylene to a certain extent:

[0012] Reduce the creep of the corrosion-resistant layer and improve the toughness: Polytetrafluoroethylene itself has good strength, but its toughness is relatively limited and its creep is large. It is easy to produce irreversible plastic deformation when subjected to force. The copolymer of methacrylate containing epoxy groups and monomers containing double bonds and phenol groups has certain flexible chain segments. After being introduced into PTFE, it can act as a "bridge" and "toughening" between the molecular chains of PTFE, so that when the material is subjected to external force, the molecular chains can consume energy, thereby improving the toughness and creep resistance of PTFE, and reducing the possibility of cracking and rupture of the corrosion-resistant layer during use.

[0013] Improve the wear resistance of the corrosion-resistant layer: The copolymer can be filled into the microstructure of PTFE, making the surface of PTFE more uniform and dense. It also has certain wear resistance, which can improve the wear resistance of PTFE to a certain extent and extend its service life in friction and wear environments.

[0014] Improve the performance uniformity of the corrosion-resistant layer: PTFE has a high melt viscosity and is difficult to process. The addition of a copolymer of methacrylate containing epoxy groups and a monomer containing double bonds and phenol groups can reduce the melt viscosity of polytetrafluoroethylene during the compression molding of the polytetrafluoroethylene material, allowing the molded material to be evenly filled in the mold, thereby improving the performance uniformity of the diaphragm material.

[0015] Maintaining high corrosion resistance: PTFE itself has excellent chemical stability. If too many other substances are added, the corrosion resistance of the corrosion-resistant layer will be reduced. The copolymer of methacrylate containing epoxy groups and monomers containing double bonds and phenol groups in this application can form bridges in the polytetrafluoroethylene molecular chain, thereby making the PTFE molecular chain arrangement more compact, reducing the channels and gaps for corrosive substances to enter the interior of the PTFE, thereby maintaining the corrosion resistance of the corrosion-resistant layer.

[0016] Optionally, the epoxy-containing methacrylate is selected from glycidyl methacrylate.

[0017] Optionally, the monomer containing a double bond and a phenol group is at least one selected from 4-allyl-2,6-di-tert-butylphenol, 4-vinylphenol, and 4-hydroxyphenyl methacrylate.

[0018] The above two monomers have the best compatibility with polytetrafluoroethylene, which can save the activation step of polytetrafluoroethylene. The corrosion-resistant layer and the reinforcement layer can be composited through a one-step adhesive method, reducing the preparation steps and improving production efficiency.

[0019] Optionally, the monomer containing a double bond and a phenol group is selected from 4-allyl-2,6-di-tert-butylphenol and 4-hydroxyphenyl methacrylate.

[0020] Optionally, the monomer containing a double bond and a phenol group is selected from 4-allyl-2,6-di-tert-butylphenol and 4-hydroxyphenyl methacrylate in a weight ratio of 1:2.

[0021] 4-allyl-2,6-di-tert-butylphenol also contains two tert-butyl groups, and 4-hydroxyphenyl methacrylate also contains an ester group. The present application found that when the above two monomers are combined, the toughness of the corrosion-resistant layer can be further improved and the adhesion performance with the reinforcement layer can be improved.

[0022] Optionally, the initiator is selected from at least one of benzoyl peroxide and dicumyl peroxide;

[0023] The vulcanizing agent is selected from sulfur;

[0024] The accelerator is selected from at least one of thiazoles, thiocarbamoyls, and guanidines;

[0025] The adhesive is epoxy resin.

[0026] Optionally, the antioxidant is selected from at least one of antioxidant RD, antioxidant 4010, antioxidant 4010NA, antioxidant ODA, antioxidant AW, antioxidant MB, antioxidant MC, and antioxidant NBC.

[0027] Optionally, the above-mentioned thiazole accelerators include but are not limited to 2-mercaptobenzothiazole (MBT), dibenzothiazyl disulfide (MBTS), sodium salt of 2-mercaptobenzothiazole, zinc salt of 2-mercaptobenzothiazole, copper salt of 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, 2-(2,4-dinitrophenyl)mercaptobenzothiazole, and 2-(2,6-diethyl-4-morpholinylthio)benzothiazole.

[0028] Optionally, the above-mentioned thiocarbamyl accelerators include but are not limited to tetramethylthiocarbamyl disulfide, tetraethylthiocarbamyl disulfide, tetramethylthiocarbamyl monosulfide, dipentamethylenethiocarbamyl disulfide, dipentamethylenethiocarbamyl disulfide, dipentamethylenethiocarbamyl tetrasulfide, dipentamethylenethiocarbamyl hexasulfide, tetrabutylthiocarbamyl disulfide, and pentamethylenethiocarbamyl tetrasulfide.

[0029] Optionally, the guanidine accelerators include but are not limited to diphenylguanidine, di-o-tolylguanidine, triphenylguanidine, di-o-tolylguanidine, and diphenylguanidine phthalate.

[0030] Optionally, the thickness of the corrosion-resistant layer is 0.2-0.3 mm, and the thickness of the reinforcement layer is 3.0-3.5 mm.

[0031] The above thickness can improve the integrity of the diaphragm and enable the diaphragm to perform at its best performance.

[0032] According to another aspect of the present application, there is provided a method for preparing the highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump as described in any one of the above, comprising the steps of:

[0033] S1: adding the corrosion-resistant layer material to a mold, and pressing under a certain pressure and temperature to obtain the corrosion-resistant layer;

[0034] S2: mixing the reinforcement layer material to obtain the reinforcement layer;

[0035] S3: coating an adhesive on one side of the corrosion-resistant layer or the reinforcement layer for bonding and laminating, and then vulcanizing and leaving it for a period of time to obtain the highly wear-resistant and corrosion-resistant diaphragm for the diaphragm pump.

[0036] Optionally, the pressing pressure in step S1 is 10-25 MPa and the temperature is 350-380°C.

[0037] Optionally, the vulcanization operation in step S3 is: vulcanization at 160-170° C. and a pressure of 8-10 MPa for 10-15 minutes; then baking at 200-220° C. for 2-3 hours, and placing for 5-7 hours.

[0038] The beneficial effects of this application include but are not limited to:

[0039] 1. According to the highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump of the present application, by providing a corrosion-resistant layer mainly composed of polytetrafluoroethylene and a reinforcement layer mainly composed of nitrile rubber, the advantages of the two can be combined to improve the overall wear resistance and corrosion resistance of the diaphragm.

[0040] 2. According to the highly wear-resistant and corrosion-resistant diaphragm for diaphragm pumps of the present application, the methacrylate containing epoxy groups and the monomer containing double bonds and phenol groups added to the corrosion-resistant layer can improve the bonding performance of the corrosion-resistant layer and the reinforcing layer, increase the bonding strength of the diaphragm material, and thus improve the durability of the diaphragm material.

[0041] 3. According to the highly wear-resistant and corrosion-resistant diaphragm for diaphragm pumps of the present application, the methacrylate containing epoxy groups and the monomer containing double bonds and phenol groups added to the corrosion-resistant layer can be polymerized under an initiator to form a copolymer. The copolymer can improve the creep resistance and toughness of the corrosion-resistant layer and reduce the possibility of cracking, rupture and other problems in the material during use.

[0042] 4. According to the highly wear-resistant and corrosion-resistant diaphragm for the diaphragm pump of the present application, the reinforcement layer is prepared by using nitrile rubber and methyl divinyl silicone rubber, which can improve the fatigue resistance and flexibility resistance of the diaphragm and further increase the service life of the diaphragm. DETAILED DESCRIPTION

[0043] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0044] Unless otherwise specified, the raw materials in the examples and comparative examples of this application were purchased from commercial channels. The initiator used in the following examples and comparative examples is benzoyl peroxide, the vulcanizing agent is sulfur, the antioxidant is antioxidant RD, the accelerator is accelerator DM, and the binder is epoxy resin; the CAS number of glycidyl methacrylate is: , the CAS number of 4-allyl-2,6-di-tert-butylphenol is: 13677-69-5; the CAS number of 4-vinylphenol is: 2628-17-3; the CAS number of 4-hydroxyphenyl methacrylate is: 31480-93-0; the CAS number of 1-methylcyclopentyl acrylate is: 178889-49-1; the CAS number of methacrylic acid is: 79-41-4;

[0045] Unless otherwise specified, the methods used in the examples and comparative examples of the present application are conventional methods in the prior art.

[0046] Example 1

[0047] This embodiment relates to a highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump and a preparation method thereof. The diaphragm includes a corrosion-resistant layer and a reinforcement layer, and the corrosion-resistant layer and the reinforcement layer are bonded together by an adhesive; wherein:

[0048] The corrosion-resistant layer comprises 100 parts of polytetrafluoroethylene, 10 parts of glycidyl methacrylate, 10 parts of 4-allyl-2,6-di-tert-butylphenol, and 1 part of initiator;

[0049] The reinforcing layer comprises 100 parts of nitrile rubber, 30 parts of methyl divinyl silicone rubber, 2 parts of vulcanizing agent, 5 parts of antioxidant and 0.1 part of accelerator.

[0050] Example 2

[0051] This embodiment relates to a highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump and a preparation method thereof. The diaphragm includes a corrosion-resistant layer and a reinforcement layer, and the corrosion-resistant layer and the reinforcement layer are bonded together by an adhesive; wherein:

[0052] The corrosion-resistant layer comprises 100 parts of polytetrafluoroethylene, 20 parts of glycidyl methacrylate, 5 parts of 4-vinylphenol, and 2 parts of initiator;

[0053] The reinforcing layer comprises 100 parts of nitrile rubber, 40 parts of methyl divinyl silicone rubber, 3 parts of vulcanizing agent, 5 parts of antioxidant and 0.4 parts of accelerator.

[0054] Example 3

[0055] This embodiment relates to a highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump and a preparation method thereof. The diaphragm includes a corrosion-resistant layer and a reinforcement layer, and the corrosion-resistant layer and the reinforcement layer are bonded together by an adhesive; wherein:

[0056] The corrosion-resistant layer comprises 100 parts of polytetrafluoroethylene, 15 parts of glycidyl methacrylate, 9 parts of 4-hydroxyphenyl methacrylate, and 2 parts of initiator;

[0057] The reinforcing layer comprises 100 parts of nitrile rubber, 35 parts of methyl divinyl silicone rubber, 3 parts of vulcanizing agent, 4 parts of antioxidant and 0.3 parts of accelerator.

[0058] Example 4

[0059] In this embodiment, 9 parts of 4-hydroxyphenyl methacrylate in Example 3 are replaced by 3 parts of 4-allyl-2,6-di-tert-butylphenol and 6 parts of 4-hydroxyphenyl methacrylate, and the rest is the same as Example 3.

[0060] Example 5

[0061] In this embodiment, 9 parts of 4-hydroxyphenyl methacrylate in Example 3 are replaced by 6 parts of 4-allyl-2,6-di-tert-butylphenol and 3 parts of 4-hydroxyphenyl methacrylate, and the rest is the same as Example 3.

[0062] Example 6

[0063] The difference between this embodiment and embodiment 3 is that 1-methylcyclopentyl acrylate is used instead of glycidyl methacrylate, and the rest is the same as embodiment 3.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 3 is that methacrylic acid is used instead of glycidyl methacrylate, and the rest is the same as Example 3.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 3 is that glycidyl methacrylate is not added, and the rest is the same as Example 3.

[0068] Comparative Example 3

[0069] The difference between this comparative example and Example 3 is that the added amount of glycidyl methacrylate is 30 parts, and the rest is the same as Example 3.

[0070] Comparative Example 4

[0071] The difference between this comparative example and Example 3 is that methacrylic acid is used instead of 4-hydroxyphenyl methacrylate, and the rest is the same as Example 3.

[0072] Comparative Example 5

[0073] The difference between this comparative example and Example 3 is that 4-hydroxyphenyl methacrylate is not added, and the rest is the same as Example 3.

[0074] Comparative Example 6

[0075] The difference between this comparative example and Example 3 is that the added amount of 4-hydroxyphenyl methacrylate is 20 parts, and the rest is the same as Example 3.

[0076] Test Case

[0077] The following tests were performed on the diaphragms prepared in the above embodiments and comparative examples: tensile properties (refer to GB / T528-2009), acid and alkali corrosion resistance (refer to GB / T1690-2010), peel strength (refer to GB / T791-1995), and flexural test (refer to GB / T13934-2006).

[0078] The results are shown in Tables 1, 2 and 3 below.

[0079] Table 1

[0080]

[0081] Table 2

[0082]

[0083]

[0084] Table 3

[0085]

[0086] According to the above data, the diaphragm prepared in this application has good corrosion resistance and wear resistance, and has high peel strength, and can be used for a long time in acid and alkali media.

[0087] According to the comparison between Example 3 and Examples 4 and 5, it can be seen that the use of specific monomers containing double bonds and phenol groups can further improve the toughness of the corrosion-resistant layer and improve the adhesion performance with the reinforcement layer; according to the comparison between Example 3 and Example 6, it can be seen that the number of carbon atoms in the epoxy group in the epoxy-containing methacrylate will affect the corrosion resistance and adhesion performance of the corrosion-resistant layer. It is speculated that the possible reason is that the number of carbon atoms will affect the density of the corrosion-resistant layer and its compatibility with the binder, thereby affecting the above two properties.

[0088] According to the comparison between Example 3 and Comparative Examples 1 and 4, it can be seen that when the substance added to the corrosion-resistant layer does not contain epoxy groups or phenol groups, the strength, corrosion resistance and peel strength of the corrosion-resistant layer with the reinforcement layer are reduced, and the number of tests of the flexural test is significantly reduced, so it is difficult to improve the creep resistance and toughness of the corrosion-resistant layer.

[0089] According to the comparison between Example 3 and Comparative Examples 2 and 5, it can be seen that when methacrylate containing epoxy groups or monomers containing double bonds and phenol groups are not added, the corrosion resistance of the corrosion-resistant layer is increased, but the mechanical strength and peel strength are significantly reduced, which further proves that the addition of these two substances can improve the toughness of the corrosion-resistant layer and the bonding strength with the reinforcement layer.

[0090] According to the comparison between the embodiment and comparative examples 3 and 6, it can be seen that when methacrylate containing epoxy groups or monomers containing double bonds and phenol groups are added in excess, the corrosion resistance of the material will be significantly reduced. Due to the decrease in corrosion resistance, the mechanical strength and flexural test results also show a significant decrease, which makes it difficult to meet the normal use requirements of the diaphragm pump. Therefore, the two substances need to be controlled within a reasonable range.

[0091] The foregoing is merely an embodiment of the present application, and the scope of protection of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the technical ideas and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump, characterized in that: It comprises a corrosion-resistant layer and a reinforcement layer, wherein the corrosion-resistant layer and the reinforcement layer are bonded together by an adhesive; wherein: The corrosion-resistant layer comprises, by weight, 100 parts of polytetrafluoroethylene, 10-20 parts of methacrylate containing epoxy groups, 5-10 parts of monomer containing double bonds and phenol groups, and 1-2 parts of initiator; The reinforcing layer comprises 100 parts of nitrile rubber, 30-40 parts of methyl divinyl silicone rubber, 2-3 parts of vulcanizing agent, 3-5 parts of antioxidant and 0.1-0.4 parts of accelerator.

2. The highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump according to claim 1, characterized in that: The methacrylate containing epoxy group is selected from glycidyl methacrylate.

3. The highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump according to claim 1, characterized in that: The monomer containing a double bond and a phenol group is selected from at least one of 4-allyl-2,6-di-tert-butylphenol, 4-vinylphenol, and 4-hydroxyphenyl methacrylate.

4. The highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump according to claim 3, characterized in that: The monomer containing a double bond and a phenol group is selected from 4-allyl-2,6-di-tert-butylphenol and 4-hydroxyphenyl methacrylate.

5. The highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump according to claim 4, characterized in that: The monomer containing a double bond and a phenol group is selected from 4-allyl-2,6-di-tert-butylphenol and 4-hydroxyphenyl methacrylate in a weight ratio of 1:

2.

6. The highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump according to claim 1, characterized in that: The initiator is selected from at least one of benzoyl peroxide and dicumyl peroxide; The vulcanizing agent is selected from sulfur; The accelerator is selected from at least one of thiazoles, thiocarbamoyls, and guanidines; The adhesive is epoxy resin.

7. The highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump according to claim 1, characterized in that: The thickness of the corrosion-resistant layer is 0.2-0.3 mm, and the thickness of the reinforcement layer is 3.0-3.5 mm.

8. The method for preparing a highly wear-resistant and corrosion-resistant diaphragm for a diaphragm pump according to any one of claims 1 to 7, characterized in that: Including steps: S1: Add the corrosion-resistant layer material mixture into the mold and press it under a certain pressure and temperature to obtain the corrosion-resistant layer; S2: mixing the reinforcement layer material to obtain the reinforcement layer; S3: coating an adhesive on one side of the corrosion-resistant layer or the reinforcement layer for bonding and laminating, and then vulcanizing and leaving it for a period of time to obtain the highly wear-resistant and corrosion-resistant diaphragm for the diaphragm pump.

9. The preparation method according to claim 8, characterized in that The pressing pressure in step S1 is 10-25 MPa and the temperature is 350-380°C.

10. The preparation method according to claim 8, characterized in that The vulcanization operation in step S3 is as follows: vulcanization at 160-170° C. and a pressure of 8-10 MPa for 10-15 minutes; then baking at 200-220° C. for 2-3 hours and placing for 5-7 hours.

Images