A primer, a preparation method and application thereof

Abstract

This application provides a primer, its preparation method, and its application, belonging to the field of chemical materials. The primer provided in this application comprises the following components: a main resin, a curing agent, and additives; wherein the main resin contains an acid-modified polyolefin resin; the curing agent includes a polyurethane curing agent containing isocyanate functional groups; and the additives include an epoxy resin containing at least two epoxy groups. Through the synergistic formulation of the main resin, curing agent, and additives, the primer of this application, after being applied to a fluoropolymer substrate, exhibits interactions between its components, providing strong interfacial strength for the adhesion between the fluoropolymer substrate and the adhesive. This significantly improves the stability and reliability of the bond between the adhesive and the substrate, which have significant polarity differences, thereby preventing cable adhesive separation when the fluoropolymer is used as a cable sheathing material.

Description

Technical Field

[0001] This invention belongs to the field of chemical materials, and particularly relates to a primer, its preparation method, and its application. Background Technology

[0002] Fluoropolymers (such as ETFE, ethylene-tetrafluoroethylene copolymer) have advantages such as high heat resistance, chemical resistance, good electrical insulation, high tensile strength, low coefficient of friction, high transparency and weather resistance, and are widely used as cable wrapping materials.

[0003] However, fluoropolymers have low surface energy and polarity, making them difficult to bond with adhesives such as EVA hot melt adhesive, TPU hot melt adhesive, and pressure-sensitive adhesive. When used as cable wrapping materials, they are prone to separation from the adhesive after being bonded to the substrate.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] This application provides a primer, a preparation method, and an application, aiming to solve or at least improve the defects in the bonding of fluoropolymers as substrates with adhesives in the prior art.

[0006] The first aspect of this application provides a primer comprising the following components: a base resin, a curing agent, and additives; wherein the base resin contains an acid-modified polyolefin resin; the curing agent includes a polyurethane curing agent containing isocyanate functional groups; and the additives include an epoxy resin containing at least two epoxy groups.

[0007] In this application, the main resin contains an acid-modified polyolefin resin. This polyolefin resin can effectively entangle with the molecular chains of PP / PE structures through a similar-miscible process. Furthermore, its molecular chains contain highly polar acid groups, which can promote effective adhesion between substrates with significantly different polarities and the adhesive, thereby improving bond strength. The curing agent is a polyurethane curing agent containing isocyanate functional groups. These isocyanate functional groups can react with the acid groups on the polyolefin resin molecular chains, promoting a suitable degree of crosslinking in the primer. This improves the primer's heat resistance and UV aging resistance while ensuring stable adhesion to the substrate. The additive, a fluorinated epoxy resin containing at least two epoxy groups, can react with the acid groups on the polyolefin resin molecular chains and with the isocyanate functional groups in the curing agent. This allows the resin to further crosslink and achieve a larger molecular weight, improving the reliability of the primer and synergistically enhancing the adhesion to fluoropolymers.

[0008] Therefore, the primer of this application, through the synergistic formulation of the main resin, curing agent and additives, after being applied to the fluoropolymer substrate, allows the components to interact with each other, providing strong interfacial strength for the adhesion between the substrate and the adhesive. This significantly improves the stability and reliability of the adhesion between the adhesive and the substrate, which have large polarity differences, thereby avoiding the separation of the cable adhesive after bonding when the fluoropolymer is used as a cable wrapping material.

[0009] In some embodiments, the components of the primer are sealed independently and mixed before use; and by weight, the weight ratio of the main resin, curing agent and additives is (1~20):1:1 when used.

[0010] In some embodiments, the main resin further contains a first solvent for dispersing the acid-modified polyolefin resin; the curing agent further contains a second solvent for dispersing the polyurethane curing agent; and the additive further contains a third solvent for dispersing the epoxy resin.

[0011] In some embodiments, by weight, the main resin comprises 3 to 20 parts of acid-modified polyolefin resin and 80 to 97 parts of the first solvent; optionally, the curing agent comprises 1 to 100 parts of polyurethane curing agent and 1 to 99 parts of the second solvent; optionally, the additive comprises 1 to 100 parts of epoxy resin and 1 to 99 parts of the third solvent.

[0012] In some embodiments, the acid functional group mass fraction of the acid-modified polyolefin resin in the main resin is 0.8% to 1.8%; optionally, the average functionality of the polyurethane curing agent is 1 to 4, preferably 2 to 4; optionally, the isocyanate functional group mass fraction of the polyurethane curing agent is 0.5% to 33.6%, preferably 10% to 30%; optionally, the molecular weight of the acid-modified polyolefin resin is 50,000 to 500,000, and the softening point is 50 to 150°C.

[0013] In some embodiments, the acid-modified polyolefin resin includes at least one of maleic anhydride or acrylic acid-modified polypropylene, polyethylene, polypropylene-ethylene copolymer, polyoctene-ethylene copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene-butadiene-styrene copolymer, styrene-isoprene, styrene-ethylene / propylene-styrene block copolymer, styrene-isoprene-styrene block copolymer, butyl rubber, polyisobutylene, nitrile rubber, isoprene rubber, poly(butadiene-acrylonitrile), synthetic polyolefin rubber, or poly(butadiene-styrene).

[0014] In some embodiments, the polyurethane curing agent includes at least one of the following: a polyether-isocyanate prepolymer, a polyester-isocyanate prepolymer, a dimer acid polyol-isocyanate prepolymer, a polyether-polyester-isocyanate prepolymer, an isocyanate-modified silane, toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, an isocyanate dimer, or an isocyanate trimer.

[0015] In some embodiments, the epoxy resin includes at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyphenol type glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, epoxidized olefin compound, heterocyclic epoxy resin or mixed type epoxy resin.

[0016] In some embodiments, the epoxy resin is a fluorinated epoxy resin, which includes at least one of the following: fluorinated bisphenol A type epoxy resin, fluorinated bisphenol F type epoxy resin, fluorinated polyphenol type glycidyl ether epoxy resin, fluorinated aliphatic glycidyl ether epoxy resin, fluorinated glycidyl ester type epoxy resin, fluorinated glycidyl amine type epoxy resin, fluorinated epoxidized olefin compound, fluorinated heterocyclic epoxy resin, or fluorinated mixed type epoxy resin.

[0017] In some embodiments, the fluorine mass fraction in the fluorinated epoxy resin is 1 to 50%.

[0018] In some embodiments, the first solvent includes at least one of benzene, toluene, xylene, cyclohexane, cyclohexanone, or methylcyclohexanone; optionally, the second and third solvents include at least one of methyl acetate, ethyl acetate, propyl acetate, acetone, or methyl isobutyl ketone.

[0019] A second aspect of this application provides a method for preparing a primer, comprising:

[0020] The main resin preparation steps are as follows: acid-modified polyolefin resin and first solvent are stirred and mixed, and the mixture is heated to reflux until the resin is completely melted to obtain the main resin.

[0021] Curing agent preparation steps: Stir and mix the polyurethane curing agent and the second solvent, and heat until the resin is completely melted to obtain the curing agent;

[0022] Additive preparation steps: Stir and mix epoxy resin and a third solvent, and heat until the resin is completely melted to obtain the additive;

[0023] The main resin, curing agent, and additives should be stored separately in sealed containers.

[0024] Further, the stirring speed in the main resin preparation step, the curing agent preparation step, and the additive preparation step is 180 rpm to 220 rpm; optionally, the temperature in the main resin preparation step is 100 to 130°C; optionally, the temperature in the curing agent preparation step and the additive preparation step is controlled at 45 to 55°C.

[0025] A third aspect of this application provides a primer as described above, which is used to promote the adhesion of a fluoropolymer substrate to an adhesive. Detailed Implementation

[0026] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0027] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0028] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0029] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0030] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" may also include or contain other components not listed, or may include only or contain the listed components.

[0031] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0032] As mentioned above, the general inventive concept of this application is to provide a primer. By designing the components of the primer, the components can work together and interact to overcome the defects of fluoropolymers as substrates, such as low surface energy, difficulty in wetting, large polarity difference with adhesives, and easy interface peeling after bonding.

[0033] Based on the above-described inventive concept, embodiments of this application provide a primer comprising the following components: a base resin, a curing agent, and additives; wherein the base resin contains an acid-modified polyolefin resin; the curing agent includes a polyurethane curing agent containing isocyanate functional groups; and the additives include an epoxy resin containing at least two epoxy groups.

[0034] It is understandable that fluoropolymers, as substrates, have low polarity due to the chemical bonds formed between fluorine atoms and other atoms. In contrast, most adhesives, such as EVA hot melt adhesives, TPU hot melt adhesives, and pressure-sensitive adhesives, are usually highly polar substances. The polarity difference between the two can hinder the interaction at the bonding interface. In this embodiment, the main resin in the primer contains acid-modified polyolefin resin. Polyolefin resin can effectively entangle with the molecular chains of PP / PE structures in a similar-miscible manner, and its molecular chains contain highly polar acid groups, which can promote the effective adhesion between the substrate with a large difference in polarity and the adhesive, thereby improving the bonding strength.

[0035] Furthermore, the isocyanate functional groups in the curing agent can react with the acid groups on the polyolefin resin molecular chain, promoting the primer to have a suitable degree of crosslinking. On the one hand, a suitable degree of crosslinking is beneficial to effectively reduce the free movement of the primer molecular chain, enhance the primer's thermal stability, high temperature resistance, and UV aging resistance, and on the other hand, it is beneficial to improve the physical bonding force between the primer and the substrate, enhance the adhesion and interfacial bonding strength between the primer and the substrate, and ensure a stable bond between the primer and the substrate.

[0036] Furthermore, due to the high electronegativity of fluorine in fluoropolymers, their surface energy is low, resulting in a certain degree of hydrophobicity. This makes it difficult for adhesives to achieve good wetting and adhesion on their surfaces. The additive design in this embodiment contains difunctional or higher-functional epoxy resins that can react with the acid groups on the polyolefin resin molecular chains and with the isocyanate functional groups in the curing agent. This allows the resin to crosslink and achieve a larger molecular weight, improving the reliability of the primer and assisting in enhancing the adhesion and bonding ability to fluoropolymers. Thus, through the synergistic formulation of the main resin, curing agent, and additives, the primer provides strong interfacial strength for the bonding between the fluoropolymer substrate and the adhesive, significantly improving the stability and reliability of the bond.

[0037] Furthermore, the components of the primer are sealed independently and mixed before use; and by weight, the weight ratio of the main resin, curing agent and additives is (1~20):1:1 when used.

[0038] In this embodiment, the components of the primer are stored independently and mixed before use. This effectively prevents interactions or degradation between components, maintains the stability and activity of each component, and ensures that the quality and performance of the primer are not affected. Furthermore, storing the components separately allows for mixing according to actual needs and proportions, increasing flexibility and enabling better control over the primer's formulation and performance. When using the primer, the weight ratio of the main resin, curing agent, and additives is designed to be (1~20):1:1. Within this weight range, it is beneficial to improve the adhesion of the adhesive to the substrate and to improve post-bonding aging, thereby enhancing the stability and reliability of the bond.

[0039] For example, when using a primer, the weight ratio of the main resin, curing agent, and additives can be 1:1:1, 1.5:1:1, 2:1:1, 2.5:1:1, 3:1:1, 3.5:1:1, 4:1:1, 4.5:1:1, 5:1:1, 5.5:1:1, 6:1:1, 6.5:1:1, 7:1:1, 7.5:1:1, 8:1:1, 8.5:1:1, 9:1:1, 9.5:1:1, 10:1:1, or 10.5:1:1. Any weight ratio within the range of 1:1:1, 11.5:1:1, 12:1:1, 12.5:1:1, 13:1:1, 13.5:1:1, 14:1:1, 14.5:1:1, 15:1:1, 15.5:1:1, 16:1:1, 16.5:1:1, 17:1:1, 17.5:1:1, 18:1:1, 18.5:1:1, 19:1:1, 19.5:1:1, 20:1:1 or (1~20):1:1.

[0040] In an optional embodiment of this application, the main resin further contains a first solvent for dispersing the acid-modified polyolefin resin; the curing agent further contains a second solvent for dispersing the polyurethane curing agent; and the additive further contains a third solvent for dispersing the epoxy resin. By designing the first, second, and third solvents respectively, the acid-modified polyolefin resin, polyurethane curing agent, and epoxy resin can be effectively dispersed in their respective solvents, thereby improving the compatibility between the main resin, curing agent, and additives, promoting the mutual reaction between the components, ensuring the performance stability of the primer, and thus improving the stability and reliability of the substrate after bonding with the adhesive.

[0041] In the optional embodiments of this application, by weight, the main resin contains 3 to 20 parts of acid-modified polyolefin resin and 80 to 97 parts of the first solvent; the curing agent contains 1 to 100 parts of polyurethane curing agent and 1 to 99 parts of the second solvent; the additive contains 1 to 100 parts of epoxy resin and 1 to 99 parts of the third solvent.

[0042] It should be noted that the resin solids content in the main resin affects the viscosity of the primer. By designing the acid-modified polyolefin resin to be 3-20 parts and the first solvent to be 80-97 parts, it is beneficial to maintain the resin solids content in the main resin within a suitable range, thus effectively ensuring the final strength of the primer. In the curing agent, the polyurethane curing agent is 1-100 parts and the second solvent is 1-99 parts. Within this weight range, it helps to promote the cross-linking reaction between the curing agent and the main resin, resulting in a suitable degree of cross-linking in the primer. This improves the weather resistance of the primer while ensuring stable adhesion to the substrate. In the additives, the epoxy resin is 1-100 parts and the third solvent is 1-99 parts. Within this weight range, it helps to ensure that fluorine atoms are successfully grafted onto the polyolefin resin molecular chain, thereby improving the wettability of the primer to the substrate and promoting the adhesion between the primer and the substrate.

[0043] In the optional embodiments of this application, the acid-modified polyolefin resin has an acid functional group mass fraction of 0.8% to 1.8% in the main resin; the average functionality of the polyurethane curing agent is 1 to 4, preferably 2 to 4; the isocyanate functional group mass fraction of the polyurethane curing agent is 0.5% to 33.6%, preferably 10% to 30%; the molecular weight of the acid-modified polyolefin resin is 50,000 to 500,000, and the softening point is 50 to 150°C.

[0044] It is important to clarify that the acid functional group mass fraction in this embodiment refers to the grafting rate of acid groups, that is, the percentage of the mass of grafted acid functional groups to the total mass of the acid-modified polyolefin resin. An excessively high acid functional group mass fraction leads to excessively high polarity in the primer, resulting in decreased adhesion to the substrate. Conversely, a low acid functional group mass fraction results in insufficient acid groups in the main resin, affecting the crosslinking effect of the main resin and reducing the chemical resistance and weather resistance of the primer. By designing the acid functional group mass fraction of the acid-modified polyolefin resin to be 0.8%~1.8%, it is beneficial to maintain the polarity of the primer within a suitable range, improving the adhesion between the primer and the substrate, and ensuring the stability and reliability of the bonded surface. The acid-modified polyolefin resin has a molecular weight of 50,000-500,000 and a softening point of 50-150℃, which facilitates similar-miscible entanglement with the molecular chains of PP / PE structures, improving the compatibility between the primer and the substrate, and enabling effective adhesion.

[0045] Furthermore, if the average functionality of the polyurethane curing agent is too high, it will cause excessive cross-linking of the primer, affecting its normal use as a primer. Conversely, if the average functionality of the polyurethane curing agent is too low, it will result in insufficient cross-linking of the primer, leading to inadequate curing. By designing the average functionality of the polyurethane curing agent to be 1 to 4, preferably 2 to 4, the main resin can be appropriately cross-linked, thereby maintaining a suitable cross-linking density in the primer and improving the adhesion between the primer and the substrate. The isocyanate functional group mass fraction of the polyurethane curing agent is 0.5% to 33.6%, preferably 10% to 30%. Within this mass fraction range, sufficient reactivity of the curing agent can be ensured while helping to control the curing rate of the main resin.

[0046] It should be clarified that the acid in the acid-modified polyolefin resin in this embodiment can be maleic anhydride or acrylic acid. By introducing highly polar side groups (maleic anhydride or acrylic acid) into the main chain of the polyolefin resin, the primer can become a bridge to improve the adhesion and compatibility between high-polarity materials and low-polarity materials.

[0047] In the optional embodiments of this application, the acid-modified polyolefin resin includes at least one of the following: maleic anhydride or acrylic acid-modified polypropylene, polyethylene, polypropylene-ethylene copolymer, polyoctene-ethylene copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene-butadiene-styrene copolymer, styrene-isoprene, styrene-ethylene / propylene-styrene block copolymer, styrene-isoprene-styrene block copolymer, butyl rubber, polyisobutylene, nitrile rubber, isoprene rubber, poly(butadiene-acrylonitrile), synthetic polyolefin rubber, or poly(butadiene-styrene). As acid-modified polyolefin resins, these substances can effectively entangle with the molecular chains of PP / PE structures, promoting effective bonding between substrates with significantly different polarities and the adhesive, thereby improving adhesive strength.

[0048] In the optional embodiments of this application, the polyurethane curing agent includes at least one of the following: polyether and isocyanate synthetic prepolymer, polyester and isocyanate synthetic prepolymer, dimer acid polyol and isocyanate synthetic prepolymer, polyether and polyester and isocyanate synthetic prepolymer, isocyanate modified silane, toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), isocyanate dimer, or isocyanate trimer. The polyurethane curing agent in this embodiment can be one or more of the above substances, such that the average functionality of the polyurethane curing agent is in the range of 1 to 4. All of the above substances, as polyurethane curing agents, contain isocyanate functional groups, which can react with acid groups on the polyolefin resin molecular chain, promoting a suitable degree of crosslinking in the primer. This improves the primer's heat resistance and UV aging resistance while ensuring stable adhesion of the primer to the substrate.

[0049] In some embodiments, the polyurethane curing agent is designed with isocyanate-modified silane. The isocyanate-modified silane has isocyanate functional groups and silane functional groups to better react with the acid groups on the polyolefin resin molecular chain, promoting a more suitable degree of crosslinking in the primer. Moreover, the silicon-oxygen bond (Si-O) in the isocyanate-modified silane can condense with microscopic moisture or other active hydrogen on the substrate surface to form chemical bonds, thereby improving the adhesion of the primer to the substrate interface. At the same time, the silicon-oxygen bond (Si-O) hydrolyzes to generate silanol, which can continue to react with isocyanate and siloxane in the system to improve the degree of crosslinking of the primer, thereby improving the aging resistance and UV resistance of the primer.

[0050] In the optional embodiments of this application, the epoxy resin is an epoxy resin containing two or more epoxy groups, including at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyphenol type glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, epoxidized olefin compound, heterocyclic epoxy resin, and mixed epoxy resin. The above substances, as epoxy resins, can react with the acid groups and isocyanate functional groups on the polyolefin resin molecular chain, respectively, thereby crosslinking the resin to obtain a larger molecular weight, improving the reliability of the primer and assisting in improving the adhesion to fluoropolymers.

[0051] In some embodiments, the additive is designed with a fluorinated epoxy resin, which can react with acid groups on the polyolefin resin molecular chain and with isocyanate functional groups in the curing agent to effectively graft fluorine atoms onto the resin molecular chain, thereby improving the wettability between the primer and the substrate. This allows the primer to effectively wet the surface of the fluoropolymer substrate, and the fluorine atoms in the primer can also generate intermolecular forces with the fluorine atoms in the substrate to further synergistically improve the adhesion and bonding ability of the primer to the fluoropolymer.

[0052] Furthermore, in this embodiment, the fluorine mass fraction in the fluorinated epoxy resin is 1~50%, which can ensure that the fluorine content in the additive is within a suitable range, so as to effectively graft fluorine atoms onto the polyolefin resin molecular chain, improve the wettability of the primer to the substrate, and ensure that the fluorine atoms in the primer and the fluorine atoms in the substrate generate intermolecular forces, thereby promoting the adhesion and bonding ability between the primer and the substrate, and realizing a stable and reliable bond between the adhesive and the substrate.

[0053] In the optional embodiments of this application, the fluorinated epoxy resin includes at least one of the following: fluorinated bisphenol A type epoxy resin, fluorinated bisphenol F type epoxy resin, fluorinated polyphenol type glycidyl ether epoxy resin, fluorinated aliphatic glycidyl ether epoxy resin, fluorinated glycidyl ester type epoxy resin, fluorinated glycidyl amine type epoxy resin, fluorinated epoxidized olefin compound, fluorinated heterocyclic epoxy resin, or fluorinated mixed epoxy resin. The above substances, as fluorinated epoxy resins, can react with the acid groups and isocyanate functional groups on the polyolefin resin molecular chain to graft fluorine atoms onto the polyolefin resin molecular chain, improve the wettability of the primer to the substrate, and after grafting, the fluorine atoms can also generate intermolecular forces with the fluorine atoms in the substrate, thereby effectively promoting the adhesion between the primer and the substrate.

[0054] In the optional embodiments of this application, the first solvent includes at least one of benzene, toluene, xylene, cyclohexane, cyclohexanone, or methylcyclohexanone, all of which can disperse acid-modified polyolefin resins when used as the first solvent; the second and third solvents include at least one of methyl acetate, ethyl acetate, propyl acetate, acetone, or methyl isobutyl ketone; all of which can disperse polyurethane curing agents and epoxy resins when used as the second and third solvents.

[0055] Another embodiment of this application also provides a method for preparing a primer, comprising:

[0056] The main resin preparation steps are as follows: acid-modified polyolefin resin and first solvent are stirred and mixed, and the mixture is heated to reflux until the resin is completely melted to obtain the main resin.

[0057] Curing agent preparation steps: Stir and mix the polyurethane curing agent and the second solvent, and heat until the resin is completely melted to obtain the curing agent;

[0058] Additive preparation steps: Stir and mix epoxy resin and a third solvent, and heat until the resin is completely melted to obtain the additive;

[0059] The main resin, curing agent, and additives should be stored separately in sealed containers.

[0060] It is understandable that in the main resin preparation step, by stirring and mixing the acid-modified polyolefin resin and the first solvent, and then heating and refluxing until the resin is completely melted, the acid-modified polyolefin resin can be effectively dispersed in the first solvent, thereby obtaining a uniform and stable resin system. In the curing agent preparation step, by stirring and mixing the polyurethane curing agent and the second solvent, and then heating until the resin is completely melted, the polyurethane curing agent can be effectively dispersed in the second solvent. In the additive preparation step, by stirring and mixing the epoxy resin and the third solvent, and then heating until the resin is completely melted, the epoxy resin can be dispersed in the third solvent to obtain the additive. Separately sealing and storing the main resin, curing agent, and additives allows for mixing according to actual needs and proportion requirements, avoids mutual reactions between components during storage that could reduce the primer effect, and increases the flexibility of use, allowing for better control of the primer formulation and performance.

[0061] Furthermore, the stirring speed in the main resin preparation step, the curing agent preparation step, and the additive preparation step is 180 rpm to 220 rpm; the temperature in the main resin preparation step is 100 to 130°C; and the temperature in the curing agent preparation step and the additive preparation step is controlled at 45 to 55°C. Within the above parameter range, the acid-modified polyolefin resin, polyurethane curing agent, and epoxy resin can be fully melted and dispersed in their respective solvents.

[0062] Another embodiment of this application provides a primer as described above, which is used to promote the adhesion of a fluoropolymer substrate to an adhesive.

[0063] For example, primers can be used to bond ETFE substrates to adhesives during the fabrication of stealth optical cables. Specifically, this includes:

[0064] Mix the base resin, curing agent and additives in a predetermined ratio and shake well to obtain the primer;

[0065] The ETFE substrate surface was subjected to corona treatment. A primer was applied to the corona-treated area of ​​the ETFE substrate surface and dried at 120°C for 5 minutes.

[0066] The adhesive is applied to the dried primer and cooled to form an invisible optical cable.

[0067] In this embodiment, in order to ensure stable adhesion between the adhesive and the primer, a certain pressure can be applied to the adhesive after it is applied.

[0068] Therefore, in this embodiment, by applying a primer to the surface of a fluoropolymer substrate and then applying an adhesive onto the dried primer and cooling it to form the invisible optical cable, the substrate and adhesive in the resulting cable have high adhesion and excellent weather resistance, and the cable adhesive is not prone to separation.

[0069] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0070] Example 1

[0071] ① Main resin preparation steps: Mix 3 parts OREVAC 18750 and 97 parts toluene at a stirring speed of 200 rpm, and heat to 120°C and reflux for 5 hours until the resin is completely melted to obtain the main resin. Seal and store the obtained main resin.

[0072] ② Curing agent preparation steps: Mix 5 parts MDI-100, 5 parts HT-100 and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the curing agent. Seal and store the obtained curing agent.

[0073] ③ Additive preparation steps: Mix 10 parts YX8034S and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the additive. Seal and store the obtained additive.

[0074] ④ Mix the main resin, curing agent and additives evenly in a weight ratio of 10:1:1 to obtain primer A1.

[0075] Example 2

[0076] ① Main resin preparation steps: Mix 20 parts of OREVAC 18750 and 80 parts of toluene at a stirring speed of 200 rpm, and heat to 120°C and reflux for 5 hours until the resin is completely melted to obtain the main resin. Seal and store the obtained main resin.

[0077] ② Curing agent preparation steps: Mix 5 parts MDI-100, 5 parts HT-100 and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the curing agent. Seal and store the obtained curing agent.

[0078] ③ Additive preparation steps: Mix 10 parts YX8034S and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the additive. Seal and store the obtained additive.

[0079] ④ Mix the main resin, curing agent and additives evenly in a weight ratio of 10:1:1 to obtain primer A2.

[0080] Example 3

[0081] ① Main resin preparation steps: Mix 10 parts of OREVAC 18750 and 90 parts of toluene at a stirring speed of 200 rpm, and heat to 120°C and reflux for 5 hours until the resin is completely melted to obtain the main resin. Seal and store the obtained main resin.

[0082] ② Curing agent preparation steps: Mix 5 parts MDI-100, 5 parts HT-100 and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the curing agent. Seal and store the obtained curing agent.

[0083] ③ Additive preparation steps: Mix 10 parts of fluorinated bisphenol F glycidyl ether resin and 90 parts of ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the additive. Store the obtained additive in a sealed container.

[0084] ④ Mix the main resin, curing agent and additives evenly in a weight ratio of 10:1:1 to obtain primer A3.

[0085] Example 4

[0086] ① Main resin preparation steps: Mix 15 parts of OREVAC 18750 and 85 parts of toluene at a stirring speed of 200 rpm, and heat to 120°C and reflux for 5 hours until the resin is completely melted to obtain the main resin. Seal and store the obtained main resin.

[0087] ② Curing agent preparation steps: Mix 5 parts MDI-100, 5 parts HT-100 and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the curing agent. Seal and store the obtained curing agent.

[0088] ③ Additive preparation steps: Mix 10 parts of fluorinated bisphenol F glycidyl ether resin and 90 parts of ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the additive. Store the obtained additive in a sealed container.

[0089] ④ Mix the main resin, curing agent and additives evenly in a weight ratio of 10:1:1 to obtain primer A4.

[0090] Example 5

[0091] ① Main resin preparation steps: Mix 15 parts of OREVAC 18750 and 85 parts of toluene at a stirring speed of 200 rpm, and heat to 120°C and reflux for 5 hours until the resin is completely melted to obtain the main resin. Seal and store the obtained main resin.

[0092] ② Curing agent preparation steps: Mix 5 parts MDI-100, 5 parts HT-100 and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the curing agent. Seal and store the obtained curing agent.

[0093] ③ Additive preparation steps: Mix 10 parts YX8034S and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the additive. Seal and store the obtained additive.

[0094] ④ Mix the main resin, curing agent and additives evenly in a weight ratio of 1:1:1 to obtain primer A5.

[0095] Example 6

[0096] ① Main resin preparation steps: Mix 15 parts of OREVAC 18750 and 85 parts of toluene at a stirring speed of 200 rpm, and heat to 120°C and reflux for 5 hours until the resin is completely melted to obtain the main resin. Seal and store the obtained main resin.

[0097] ② Curing agent preparation steps: Mix 5 parts MDI-100, 5 parts HT-100 and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the curing agent. Seal and store the obtained curing agent.

[0098] ③ Additive preparation steps: Mix 10 parts YX8034S and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the additive. Seal and store the obtained additive.

[0099] ④ Mix the main resin, curing agent and additives evenly in a weight ratio of 20:1:1 to obtain primer A6.

[0100] Example 7

[0101] ① Main resin preparation steps: Mix 15 parts of G1901 rubber resin and 85 parts of toluene at a stirring speed of 200 rpm, and heat to 120℃ and reflux for 5 hours until the resin is completely melted to obtain the main resin. Store the obtained main resin in a sealed container.

[0102] ② Curing agent preparation steps: Mix 5 parts MDI-100, 5 parts HT-100 and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the curing agent. Seal and store the obtained curing agent.

[0103] ③ Additive preparation steps: Mix 10 parts YX8034S and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the additive. Seal and store the obtained additive.

[0104] ④ Mix the main resin, curing agent and additives evenly in a weight ratio of 10:1:1 to obtain primer A7.

[0105] Example 8

[0106] ① Main resin preparation steps: Mix 15 parts of OREVAC 18750 and 85 parts of toluene at a stirring speed of 200 rpm, and heat to 120°C and reflux for 5 hours until the resin is completely melted to obtain the main resin. Seal and store the obtained main resin.

[0107] ② Curing agent preparation steps: Mix 10 parts of polyurethane prepolymer and 90 parts of ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the curing agent. Seal and store the obtained curing agent.

[0108] ③ Additive preparation steps: Mix 10 parts of DNE260 and 90 parts of ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the additive. Seal and store the obtained additive.

[0109] ④ Mix the main resin, curing agent and additives evenly in a weight ratio of 10:1:1 to obtain primer A8.

[0110] Example 9

[0111] ① Main resin preparation steps: Mix 15 parts of OREVAC 18750 and 85 parts of toluene at a stirring speed of 200 rpm, and heat to 120°C and reflux for 5 hours until the resin is completely melted to obtain the main resin. Seal and store the obtained main resin.

[0112] ② Curing agent preparation steps: Mix 10 parts SCA-Y25M and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the curing agent. Seal and store the obtained curing agent.

[0113] ③ Additive preparation steps: Mix 10 parts of DNE260 and 90 parts of ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the additive. Seal and store the obtained additive.

[0114] ④ Mix the main resin, curing agent and additives evenly in a weight ratio of 10:1:1 to obtain primer A9.

[0115] Comparative Example 1

[0116] ① Main resin preparation steps: Mix 15 parts of OREVAC 18750 and 85 parts of toluene at a stirring speed of 200 rpm, and heat to 120°C and reflux for 5 hours until the resin is completely melted to obtain the main resin. Seal and store the obtained main resin.

[0117] ②Use the main resin as primer B1.

[0118] Comparative Example 2

[0119] ① Main resin preparation steps: Mix 15 parts of OREVAC 18750 and 85 parts of toluene at a stirring speed of 200 rpm, and heat to 120°C and reflux for 5 hours until the resin is completely melted to obtain the main resin. Seal and store the obtained main resin.

[0120] ② Curing agent preparation steps: Mix 5 parts MDI-100, 5 parts HT-100 and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the curing agent. Seal and store the obtained curing agent.

[0121] ③ Mix the main resin and curing agent evenly at a weight ratio of 10:1 to obtain primer B2.

[0122] Comparative Example 3

[0123] ① Main resin preparation steps: Mix 15 parts of OREVAC 18750 and 85 parts of toluene at a stirring speed of 200 rpm, and heat to 120°C and reflux for 5 hours until the resin is completely melted to obtain the main resin. Seal and store the obtained main resin.

[0124] ② Additive preparation steps: Mix 10 parts YX8034S and 90 parts ethyl acetate at a stirring speed of 200 rpm, and heat to 50°C until the resin is completely melted to obtain the additive. Seal and store the obtained additive.

[0125] ③ Mix the main resin and additives evenly at a weight ratio of 10:1 to obtain primer B3.

[0126] It should be noted that in the above embodiments and comparative examples, OREVAC 18750 (maleic anhydride-modified polypropylene) as an acid-modified polyolefin resin was sourced from Arkema, France; G1901 rubber resin (maleic anhydride-modified styrene-ethylene-butadiene-styrene copolymer) as an acid-modified polyolefin resin was sourced from Kraton, USA; MDI-100 (diphenylmethane diisocyanate) as a polyurethane curing agent was sourced from Xiamen Greeda Chemical Co., Ltd.; and HT-100 (isocyanate trimer) as a polyurethane curing agent was sourced from Wanhua Chemical. Xue Group Co., Ltd., SCA-Y25M (isocyanate modified silane) as a polyurethane curing agent is sourced from Nanjing Nengde New Material Technology Co., Ltd., YX8034S (bisphenol A type epoxy resin) as an epoxy resin is sourced from Mitsubishi Chemical Co., Ltd. of Japan, fluorinated bisphenol F glycidyl ether resin as a fluorinated epoxy resin is sourced from Hubei Langbowan Biomedical Co., Ltd., and DNE260 (DCPD type epoxy resin, i.e. epoxidized olefin compound) as an epoxy resin is sourced from Complex High-Tech Materials (Shanghai) Co., Ltd.

[0127] In the above embodiments, the polyurethane prepolymer is used as a polyurethane curing agent. It is obtained by synthesizing PPG2000 and MDI at a ratio of R value of 2 at 100°C for 1 hour. The R value refers to the ratio of isocyanate groups to hydroxyl groups in PPG2000 and MDI. PPG2000 (polyether polyol 2000) is 2000LM produced by Dow Chemical Company.

[0128] The composition and proportions of the primers prepared in each embodiment and comparative example are shown in Table 1 below:

[0129] Table 1. Statistics of Primer Components and Proportions

[0130]

[0131] It should be understood that the weight ratio in Table 1 specifically refers to the weight ratio of the main resin, curing agent and additive; for example, in Parts by weight, Example 1 uses 10 parts of main resin, 1 part of curing agent and 1 part of additive to be uniformly mixed to obtain primer A1, that is, the weight ratio of main resin, curing agent and additive is 10:1:1.

[0132] Furthermore, the performance of the primers prepared in the above embodiments and comparative examples was tested using the following methods:

[0133] (1) 90° peel strength test:

[0134] The primers prepared in the above embodiments and comparative examples were uniformly brushed onto the surface of the ETFE substrate. After drying at 120°C for 5 minutes, the pressure-sensitive tape was bonded to the ETFE substrate. After standing for 20 minutes, the 90° peel strength was tested.

[0135] (2) High temperature test:

[0136] After preparing the ETFE substrate according to the above 90° peel strength test, it was placed in a 70° oven for 48 hours. After being taken out, it was placed at room temperature for 2 hours before testing the 90° peel strength.

[0137] (3) Low temperature test:

[0138] After preparing the ETFE substrate according to the above 90° peel strength test, it was placed in a -10°C refrigerator for 48 hours. After taking it out, it was placed at room temperature for 2 hours before testing the 90° peel strength.

[0139] (4) High temperature and high humidity test:

[0140] After preparing the ETFE substrate according to the above 90° peel strength test, it was placed in a constant temperature and humidity chamber at 65°C and 95%RH for 48 hours. After being taken out and placed at room temperature for 2 hours, the 90° peel strength was tested.

[0141] (5) UV aging test:

[0142] After preparing the ETFE substrate according to the above 90° peel strength test, it was placed under xenon lamp irradiation for 48 hours. After being taken out and placed at room temperature for 2 hours, the 90° peel strength was tested again.

[0143] A control group was also set up. Samples for the control group were prepared according to the above test method, with the ETFE substrates not coated with primer and marked as C. The test results are shown in Table 2 below:

[0144] Table 2. Performance Test Results Statistics

[0145]

[0146] As can be seen from Tables 1 and 2, compared with Examples 1 to 9 of this application, Control Group C did not apply a primer and directly bonded the ETFE substrate and adhesive. Its 90° peel strength, high temperature resistance, low temperature resistance, high temperature and humidity resistance, and UV aging resistance were all lower than those of the primers prepared in the various examples of this application. The primers prepared in the various examples of this application can significantly promote the stability and reliability of the bonding between the adhesive and the substrate.

[0147] Furthermore, through a comprehensive comparison of Examples 1-9 and Comparative Examples 1-3, the primers A1-A9 prepared in Examples 1-9 all contain acid-modified polyolefin resin as the main resin, polyurethane curing agents containing isocyanate functional groups as the curing agents, and epoxy resins containing at least two epoxy groups as the additives. In contrast, the primer B1 component of Comparative Example 1 does not contain curing agents or additives, the primer B2 component of Comparative Example 2 does not contain additives, and the primer B3 component of Comparative Example 3 does not contain curing agents. The 90° peel strength, high temperature resistance, low temperature resistance, high temperature and high humidity resistance, and UV aging resistance of the primers A1-A9 prepared in Examples 1-9 are all higher than those of the primers B1-B3 prepared in Comparative Examples 1-3.

[0148] Specifically, compared to Example 4, the components of primer B1 in Comparative Example 1 do not contain curing agents and additives. The 90° peel strength, high temperature resistance, low temperature resistance, high temperature and high humidity resistance, and UV aging resistance of primer B1 are all lower than those of primer A4 prepared in Example 4 of this application. It can be seen that primer B1, which lacks curing agents and additives in its components, does not significantly improve the adhesion and weather resistance of the substrate and adhesive.

[0149] Compared with Example 4, the components of primer B2 do not contain additives. The 90° peel strength, high temperature resistance, low temperature resistance, high temperature and high humidity resistance, and UV aging resistance of primer B4 are all lower than those of primer A4 prepared in Example 4 of this application. It can be seen that primer B2, which lacks additives in its components, does not significantly improve the adhesion and weather resistance of the substrate and adhesive.

[0150] Compared with Example 4, the components of primer B3 in Comparative Example 3 do not contain a curing agent. The 90° peel strength, high temperature resistance, low temperature resistance, high temperature and high humidity resistance, and UV aging resistance of primer B3 are all lower than those of primer A4 prepared in Example 4 of this application. It can be seen that primer B3, which lacks a curing agent in its components, does not significantly improve the adhesion and weather resistance of the substrate and adhesive.

[0151] Furthermore, compared to Example 7, Example 4 uses an additive containing fluorinated epoxy resin. The resulting primer A4 shows a more significant improvement in high-temperature resistance and high-temperature and high-humidity resistance compared to primer A7 prepared in Example 7. This verifies that by designing the additive with fluorinated epoxy resin, the fluorine atoms in the primer can generate intermolecular forces with the fluorine atoms in the substrate, thereby further synergistically improving the adhesion and bonding ability of the primer to the fluorinated polymer, resulting in a significant improvement in the adhesion and weather resistance of the substrate and the adhesive.

[0152] Compared to Example 8, Example 9's curing agent incorporates isocyanate-modified silane. The resulting primer A9, compared to the primer A9 prepared in Example 8, exhibits significantly improved performance in 90° peel strength, high-temperature resistance, low-temperature resistance, high-temperature and high-humidity resistance, and UV aging resistance. This demonstrates that the inclusion of isocyanate-modified silane in the curing agent, with its isocyanate and silane functional groups, allows for better reaction with acid groups on the polyolefin resin molecular chain, resulting in a more suitable degree of crosslinking in the primer. Furthermore, the silicon-oxygen bonds (Si-O) in the isocyanate-modified silane can condense with microscopic moisture or other active hydrogen on the substrate surface to form chemical bonds, thereby improving the primer's adhesion to the substrate interface and enhancing the 90° peel strength. Further improvements can be made; simultaneously, the silicon-oxygen bonds (Si-O) in the isocyanate-modified silane hydrolyze to generate silanols, which can continue to react with isocyanates and siloxanes in the system, increasing the crosslinking degree of the primer and thus improving the primer's aging resistance and UV resistance; moreover, the isocyanate-modified silane has better flexibility and elasticity, which promotes better adhesion of primer A9 under low temperature conditions, and the silicon-oxygen bonds can form silicon-oxygen chains or silicon-oxygen network structures, giving primer A9 better high temperature and high humidity resistance; thus, by introducing isocyanate-modified silane into the curing agent and reacting it with the main resin and additives, the 90° peel strength, high temperature resistance, low temperature resistance, high temperature and high humidity resistance, and UV aging resistance of the primer can be further synergistically improved. Therefore, the primer prepared in this embodiment of the application, through the synergistic formulation of the main resin, curing agent and additives, after being applied to the fluoropolymer substrate, the components interact with each other to provide strong interfacial strength for the bonding between the substrate and the adhesive. This significantly improves the stability and reliability of the bonding between the adhesive and the substrate, which have large polarity differences, thereby avoiding the separation of cable adhesive after bonding when the fluoropolymer is used as a cable wrapping material.

[0153] The technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification, provided that such combination does not contain contradictions.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A primer characterized by, The primer comprises the following components: a base resin, a curing agent, and additives; The main resin contains an acid-modified polyolefin resin. The curing agent includes a polyurethane curing agent containing isocyanate functional groups; The additive includes an epoxy resin containing at least two epoxy groups for reacting with the acid groups of the acid-modified polyolefin resin and with the isocyanate functional groups in the curing agent. Each component of the primer is sealed independently and mixed before use; and by weight, the weight ratio of the main resin, the curing agent and the additive is (1~20):1:1 when used. In the main resin, the acid-modified polyolefin resin has an acid functional group mass fraction of 0.8% to 1.8%. The average functionality of the polyurethane curing agent is 1 to 4; The isocyanate functional group mass fraction of the polyurethane curing agent is 0.5~33.6%.

2. The primer according to claim 1, characterized in that, The main resin also contains a first solvent for dispersing the acid-modified polyolefin resin; The curing agent also contains a second solvent for dispersing the polyurethane curing agent; The additive also contains a third solvent for dispersing the epoxy resin.

3. The primer according to claim 2, characterized in that, Based on parts by weight, the primer satisfies at least one of the following conditions A to C: A. In the main resin, the acid-modified polyolefin resin is 3-20 parts, and the first solvent is 80-97 parts; B. In the curing agent, the polyurethane curing agent is 1-100 parts, and the second solvent is 1-99 parts; C. In the additive, the epoxy resin is 1 to 100 parts and the third solvent is 1 to 99 parts.

4. The primer according to claim 1, characterized in that, The primer meets the following condition D: D. The molecular weight of the acid-modified polyolefin resin is 50,000-500,000, and the softening point is 50-150℃.

5. The primer according to any one of claims 1 to 4, characterized in that, The primer meets any one of the following conditions E~J: E. The acid-modified polyolefin resin includes at least one of the following: maleic anhydride or acrylic acid modified polypropylene, polyethylene, polypropylene-ethylene copolymer, polyoctene-ethylene copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene-butadiene-styrene copolymer, styrene-isoprene, styrene-ethylene / propylene-styrene block copolymer, styrene-isoprene-styrene block copolymer, polyisobutylene, nitrile rubber, poly(butadiene-acrylonitrile), synthetic polyolefin rubber, or poly(butadiene-styrene). F. The acid-modified polyolefin resin includes at least one of maleic anhydride or acrylic acid-modified butyl rubber or isoprene rubber; G. The polyurethane curing agent comprises at least one of the following: polyether and isocyanate synthetic prepolymer, polyester and isocyanate synthetic prepolymer, dimer acid polyol and isocyanate synthetic prepolymer, polyether and polyester and isocyanate synthetic prepolymer, isocyanate modified silane, toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, isocyanate dimer or isocyanate trimer; H. The epoxy resin includes at least one of polyphenolic glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, epoxidized olefin compound, heterocyclic epoxy resin or mixed epoxy resin. I. The epoxy resin is a fluorinated epoxy resin, which includes at least one of the following: fluorinated polyphenol glycidyl ether epoxy resin, fluorinated aliphatic glycidyl ether epoxy resin, fluorinated glycidyl ester epoxy resin, fluorinated glycidyl amine epoxy resin, fluorinated epoxidized olefin compound, fluorinated heterocyclic epoxy resin, or fluorinated mixed epoxy resin. J. The epoxy resin is a fluorinated epoxy resin, and the fluorine mass fraction in the fluorinated epoxy resin is 1~50%.

6. The primer according to claim 2, characterized in that, The primer satisfies at least one of the following conditions K~L: K, the first solvent includes at least one of benzene, toluene, xylene, cyclohexane, cyclohexanone or methylcyclohexanone; L, the second solvent, and the third solvent include at least one of methyl acetate, ethyl acetate, propyl acetate, acetone, or methyl isobutyl ketone.

7. A method for preparing a primer as described in any one of claims 1 to 6, characterized in that, include: The main resin preparation steps are as follows: acid-modified polyolefin resin and first solvent are stirred and mixed, and the mixture is heated to reflux until the resin is completely melted to obtain the main resin. Curing agent preparation steps: Stir and mix the polyurethane curing agent and the second solvent, and heat until the resin is completely melted to obtain the curing agent; Additive preparation steps: Stir and mix epoxy resin and a third solvent, and heat until the resin is completely melted to obtain the additive; The main resin, the curing agent, and the additives are stored separately in sealed containers.

8. The preparation method according to claim 7, characterized in that, The preparation method satisfies at least one of the following conditions a to c: a. The stirring speed in the main resin preparation step, curing agent preparation step and additive preparation step is 180rpm~220rpm; b. The temperature in the main resin preparation step is 100~130°C; c. The temperature is controlled at 45~55°C in the curing agent preparation step and the additive preparation step.

9. The primer according to any one of claims 1 to 6, and its use in promoting the adhesion between the fluoropolymer substrate and the adhesive.

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