High-stability single-component epoxy resin adhesive capable of being processed at normal temperature

Abstract

The invention relates to the technical field of adhesives, and discloses a normal-temperature processing high-stability single-component epoxy resin adhesive which comprises the following components in parts by mass (based on the total amount of all epoxy group-containing components being 100 parts): a, 70-90 parts of a polyepoxy compound; b, 10 to 30 parts of glycidyl acrylate or glycidyl methacrylate; c, 5 to 15 parts of an acrylic ester reactive diluent; and d, an epoxy resin latent curing agent and an accelerator: 8-10 parts of the curing agent and 2-6 parts of the accelerator. According to the high-stability single-component epoxy resin adhesive capable of being processed at normal temperature, through the low viscosity characteristics of the component b and the component c, a resin system can be stirred and ground at normal temperature without heating, the problem that a latent curing agent is activated in advance due to high temperature in a traditional process is solved, and a prepolymer prepared in the early stage is stable in viscosity and high in stability. The curing agent in the system is in a latent state, so that the storage periods of the adhesive and the prepreg are effectively prolonged, and gel failure is not easy to occur.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a room-temperature processing high-stability single-component epoxy resin adhesive. Background Technology

[0002] One-component epoxy resin adhesives are widely used in industrial production, medical devices, and composite materials due to their advantages such as no need for on-site mixing and ease of use. Their traditional preparation method typically involves stirring and grinding epoxy resin, latent curing agents, accelerators, coupling agents, and additives such as pigments and fillers at temperatures ranging from 25 to 80°C. The core requirement is that the resin system must maintain a viscosity that facilitates processing.

[0003] However, commonly used epoxy resins are mostly viscous liquids or solids at room temperature. In order to reduce the processing viscosity, the system needs to be controlled within a certain temperature range. However, prolonged heating of the resin system can easily lead to the premature activation of some latent curing agents, which seriously affects the shelf life of adhesives and prepreg products, and may even cause gel failure, thus limiting its application in scenarios with high requirements for storage stability.

[0004] Therefore, developing a single-component epoxy resin adhesive that can be processed and prepared at room temperature, has a long storage period, and exhibits excellent post-crosslinking and curing properties has become a pressing technical problem to be solved in this field. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a room-temperature processed, highly stable single-component epoxy resin adhesive. It has the advantages of being able to be processed at room temperature, being stable in storage, and having excellent post-crosslinking and curing performance. This solves the problems of traditional single-component epoxy resin adhesives in the prior art, such as the need for heating during processing, the easy premature activation of latent curing agents, and the short shelf life.

[0006] (II) Technical Solution To achieve the aforementioned objectives of room-temperature processability, storage stability, and excellent post-crosslinking and curing performance, this invention provides the following technical solution: a room-temperature processable, highly stable single-component epoxy resin adhesive, comprising the following components by weight (based on a total of 100 parts of all epoxy-containing components): a. Polyepoxide: 70-90 parts; b. Glycidyl acrylate or glycidyl methacrylate: 10-30 parts; c. Acrylate reactive diluent: 5-15 parts; d. Latent curing agent and accelerator for epoxy resin: 8-10 parts curing agent, 2-6 parts accelerator; e. Initiator: 1-3 parts; f. Auxiliary additives: appropriate amounts of fumed silica, defoamer, and coupling agent.

[0007] Furthermore, the polyepoxide compound in component a is selected from bisphenol polyglycidyl ether, epoxidized phenol-phenolic varnish, bisphenol-phenolic varnish, or o-cresol-phenolic varnish.

[0008] Furthermore, in the molecule of glycidyl acrylate or glycidyl methacrylate in component b, the unsaturated carboxyl group is a monofunctional group; in the molecule of acrylate reactive diluent in component c, the unsaturated group is a monofunctional group.

[0009] Furthermore, the latent curing agent in component d is ultrafine dicyandiamide, and the accelerator is organic urea; the initiator in component e is an organic peroxide initiator or a photoinitiator, and the organic peroxide initiator is cyclohexanone peroxide.

[0010] Furthermore, component f may also contain 10 parts of titanium dioxide and 30 parts of silica powder; the acrylate reactive diluent in component c is isobornyl methacrylate.

[0011] Furthermore, the method for preparing the adhesive includes the following steps: (1) Mix components a, b, c, d, and f in proportion, and stir, disperse, and grind at high speed for 1-2 hours at room temperature or 30-40℃; (2) During the grinding process, component e initiates a bulk polymerization reaction of components b and c to generate a prepolymer with a preset degree of polymerization. The degree of polymerization of the prepolymer is controlled by equivalent calculation so that the viscosity or softening point of the system meets the preset technical requirements and the finished adhesive is obtained.

[0012] Furthermore, the adhesive can be directly used for bonding products such as disposable syringes, or for preparing glass fiber and carbon fiber epoxy resin prepregs.

[0013] Furthermore, when the adhesive is used in the preparation of prepreg, the prepolymer is formed at 50-70°C after prepreg treatment; when the adhesive or prepreg is processed in the later stage, it is heat-treated at 120-150°C for 30-40 minutes to achieve cross-linking and curing.

[0014] (III) Beneficial Effects Compared with the prior art, the present invention provides a room-temperature processed, highly stable single-component epoxy resin adhesive, which has the following beneficial effects: 1. This room-temperature processing high-stability single-component epoxy resin adhesive utilizes the low viscosity characteristics of components b and c to enable the resin system to be stirred and ground at room temperature without the need for heating. This avoids the problem of premature activation of latent curing agents caused by high temperatures in traditional processes. Furthermore, the prepolymer formed in the early stage has a stable viscosity, and the curing agent in the system is in a latent state, effectively extending the storage period of the adhesive and prepreg and making it less prone to gel failure.

[0015] 2. This room-temperature processed, high-stability single-component epoxy resin adhesive allows for flexible adjustment of the adhesive's viscosity or softening point by adjusting the degree of polymerization of the prepolymer through equivalent calculations. This adapts it to different application scenarios (such as bonding disposable syringes and preparing fiber prepregs). Furthermore, the high-crosslink density product formed by subsequent crosslinking and curing exhibits excellent bonding strength, solder resistance, and mechanical properties, meeting the requirements of industrial and medical applications. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the components of the single-component epoxy resin adhesive of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1 A room-temperature processed, highly stable one-component epoxy resin adhesive, comprising the following components by weight (based on a total of 100 parts of all epoxy-containing components): a. Polyepoxide: 70-90 parts; b. Glycidyl acrylate or glycidyl methacrylate: 10-30 parts; c. Acrylate reactive diluent: 5-15 parts; d. Latent curing agent and accelerator for epoxy resin: 8-10 parts curing agent, 2-6 parts accelerator; e. Initiator: 1-3 parts; f. Auxiliary additives: appropriate amounts of fumed silica, defoamer, and coupling agent.

[0019] Example 1: Single-component epoxy resin adhesive for disposable syringes Raw material composition: a. Bisphenol-A type epoxy resin (E51): 80 parts; b. Glycidyl methacrylate: 20 parts; c. Isoborneol methacrylate: 10 parts; d. Ultrafine dicyandiamide: 9 parts; Organic urea accelerator: 4 parts; e. Cyclohexanone peroxide: 2 parts; f. 10 parts titanium dioxide, 30 parts silica powder, appropriate amounts of fumed silica, defoamer, and coupling agent.

[0020] Preparation process: At 35°C, all the above components were mixed and put into a high-speed dispersing mill for stirring and grinding for 1.5 hours. During the grinding process, cyclohexanone peroxide initiated the bulk polymerization of the unsaturated double bonds of glycidyl methacrylate and isobornyl methacrylate to generate a prepolymer. The viscosity of the adhesive system corresponding to the prepolymer was tested to be 8000-12000 mPo·s (25°C), which meets the process requirements for bonding disposable syringes. After being packaged, the material showed no gelation after being stored under sealed conditions at room temperature for 6 months.

[0021] Instructions for use: Apply the adhesive to the bonding surface of the syringe, and after bonding, heat-treat at 120℃ for 30 minutes to complete cross-linking and curing; after curing, the bonding strength is ≥3.5MPa and can withstand 100 wipes with medical alcohol without falling off.

[0022] Example 2: One-component epoxy resin adhesive for glass fiber prepreg Raw material composition: a. Cyclooxygenated phenolic varnish: 75 parts; b. Glycidyl acrylate: 25 parts; c. Isoborneol methacrylate: 8 parts; d. Ultrafine dicyandiamide: 8 parts; Organic urea accelerator: 3 parts; e. Cyclohexanone peroxide: 1.5 parts; f. Appropriate amounts of fumed silica, defoamer, and coupling agent.

[0023] Preparation process: At room temperature (25℃), components a, b, c, d, and f were mixed and dispersed by high-speed stirring and grinding for 1 hour. After prepreg treatment using conventional industrial glass fiber prepreg methods, the mixture was placed in a 60℃ environment for 30 minutes. An initiator initiated the polymerization of components b and c to form a prepolymer. The prepreg was tested and found to have a softening point of 55-65℃, which meets the process requirements for subsequent compression molding of the prepreg.

[0024] Application method: After cutting the prepreg, lay it in layers, mold it at 150℃ and 0.5MPa pressure and keep it warm for 40 minutes to complete the cross-linking and curing; after curing, the flexural strength of the composite material is ≥1200MPa and the tensile strength is ≥800MPa.

[0025] In summary, this room-temperature processing high-stability single-component epoxy resin adhesive, through the low viscosity characteristics of components b and c, allows the resin system to be stirred and ground at room temperature without the need for heating. This avoids the problem of premature activation of latent curing agents caused by high temperatures in traditional processes. Furthermore, the prepolymer formed in the early stage has a stable viscosity, and the curing agent in the system is in a latent state, effectively extending the storage period of the adhesive and prepreg and making it less prone to gel failure.

[0026] Furthermore, by adjusting the degree of polymerization of the prepolymer through equivalent calculation, the viscosity or softening point of the adhesive can be flexibly adjusted to suit different application scenarios (such as bonding of disposable syringes and preparation of fiber prepregs). Moreover, the high cross-linking density product formed by the later cross-linking and curing has excellent bonding strength, solder resistance and mechanical properties, meeting the requirements of industrial and medical fields.

[0027] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0028] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A single-component epoxy resin adhesive with high stability during room temperature processing, characterized in that: It contains the following components by weight (based on a total of 100 parts of all epoxy-containing components): a. Polyepoxide: 70-90 parts; b. Glycidyl acrylate or glycidyl methacrylate: 10-30 parts; c. Acrylate reactive diluent: 5-15 parts; d. Latent curing agent and accelerator for epoxy resin: 8-10 parts curing agent, 2-6 parts accelerator; e. Initiator: 1-3 parts; f. Auxiliary additives: appropriate amount of fumed silica, defoamer, coupling agent.

2. The room-temperature processing high-stability single-component epoxy resin adhesive according to claim 1, characterized in that: The polyepoxide compound in component a is selected from bisphenol polyglycidyl ether, epoxidized phenol-phenolic varnish, bisphenol-phenolic varnish or o-cresol-phenolic varnish.

3. The room-temperature processing high-stability single-component epoxy resin adhesive according to claim 1, characterized in that: In component b, the unsaturated carboxyl group in the glycidyl acrylate or glycidyl methacrylate molecule is a monofunctional group; in component c, the unsaturated group in the acrylate reactive diluent molecule is a monofunctional group.

4. The room-temperature processing high-stability single-component epoxy resin adhesive according to claim 1, characterized in that: The latent curing agent in component d is ultrafine dicyandiamide, and the accelerator is organic urea; the initiator in component e is an organic peroxide initiator or a photoinitiator, and the organic peroxide initiator is cyclohexanone peroxide.

5. The room-temperature processing high-stability single-component epoxy resin adhesive according to claim 1, characterized in that: Component f may also contain 10 parts of titanium dioxide and 30 parts of silica powder; the acrylate reactive diluent in component c is isobornyl methacrylate.

6. The room-temperature processing high-stability single-component epoxy resin adhesive according to claim 1, characterized in that: The preparation method includes the following steps: (1) Mix components a, b, c, d, and f in proportion, and stir, disperse, and grind at high speed for 1-2 hours at room temperature or 30-40℃; (2) During the grinding process, component e initiates a bulk polymerization reaction of components b and c to generate a prepolymer with a preset degree of polymerization. The degree of polymerization of the prepolymer is controlled by equivalent calculation so that the viscosity or softening point of the system meets the preset technical requirements and the finished adhesive is obtained.

7. A room-temperature processing high-stability single-component epoxy resin adhesive according to claims 1-5, characterized in that: The adhesive can be used directly for bonding products such as disposable syringes, or for preparing epoxy resin prepregs for glass fibers and carbon fibers.

8. The room-temperature processing high-stability single-component epoxy resin adhesive according to claim 7, characterized in that: When the adhesive is used in the preparation of prepreg, the prepolymer is formed at 50-70°C after prepreg treatment; when the adhesive or prepreg is processed in the later stage, it is heat-treated at 120-150°C for 30-40 minutes to achieve cross-linking and curing.

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