Low-shrinkage modified light-cured resin and preparation method thereof

Abstract

The invention belongs to the technical field of preparation of epoxy binders, and particularly relates to low-shrinkage modified light-cured resin and a preparation method thereof. The problem of workpiece deformation caused by shrinkage in the common technology is solved. The low-shrinkage modified light-cured resin is composed of a main agent and a curing agent, the mass ratio of the main agent to the curing agent is 100: 3-10, and the main agent is composed of 30-80 parts of organic silicon modified epoxy resin, 0-30 parts of hyperbranched epoxy resin, 0-20 parts of reactive diluent, 0-40 parts of filler and 0-5 parts of anti-settling agent. The curing agent consists of 1-5 parts of a light curing agent and 2-5 parts of a sensitizing agent. According to the invention, four-functional-group organosilicon epoxy is used as a resin main body, and self-made hyperbranched epoxy is used as a toughening agent, so that the toughness of the resin can be improved while the shrinkage rate of the resin is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of epoxy adhesive preparation, and in particular relates to a low-shrinkage modified photocurable resin and a preparation method thereof. Background Art

[0002] Light-curing resin is composed of resin monomers and prepolymers, contains active functional groups, can be irradiated by ultraviolet light to initiate polymerization reaction by photosensitizer, and form insoluble coating film. Bisphenol A epoxy acrylate has the characteristics of fast curing speed, good chemical solvent resistance and high hardness. Polyurethane acrylate has the characteristics of good flexibility and wear resistance. Light-curing composite resin is a commonly used filling and repair material in stomatology. Because of its beautiful color and certain compressive strength, it plays an important role in clinical application.

[0003] With the development of science and technology, photocurable resins are gradually used in 3D printing, electronic equipment and component assembly. Photocurable resins can polymerize and cure quickly under ultraviolet light, but they shrink significantly during curing, causing the material to deform. In addition, most photocurable resins on the market have problems such as high brittleness, low toughness and easy fracture after curing. Therefore, it is necessary to reduce the curing shrinkage of photocurable resins and improve their toughness and strength.

[0004] Therefore, it is urgent to propose a low-shrinkage modified photocurable resin and a preparation method to solve the above technical problems. Summary of the invention

[0005] The purpose of the present invention is to solve the problem of workpiece deformation caused by shrinkage formed by common technologies. A brief overview of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to determine the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.

[0006] The technical solution of the present invention:

[0007] A low shrinkage modified photocurable resin, the low shrinkage modified photocurable resin is composed of a main agent and a curing agent;

[0008] The mass ratio of the main agent to the curing agent is 100 parts: 3-10 parts;

[0009] The main agent is composed of 30-80 parts of organosilicon-modified epoxy resin, 0-30 parts of hyperbranched epoxy resin, 0-20 parts of active diluent, 0-40 parts of filler and 0-5 parts of anti-settling agent;

[0010] The curing agent consists of 1-5 parts of a photocuring agent and 2-5 parts of a sensitizer.

[0011] Preferably, the organosilicon-modified epoxy resin contains 2-4 epoxy groups.

[0012] Preferably, the active diluent is one of poly(ethylene glycol) diacrylate, monoepoxy acryl glycidyl ether, phenyl glycidyl ether, diepoxy ethylene glycol diglycidyl ether, resorcinol diglycidyl ether, butyl glycidyl ether, 1,4-butanediol diglycidyl ether and polypropylene glycol diglycidyl ether.

[0013] Preferably, the filler is one of silicon dioxide, titanium dioxide and spherical aluminum oxide.

[0014] Preferably, the anti-settling agent is one of suspended fumed silica, nonionic polyoxyethylene fatty amine, polyoxyethylene fatty alcohol sulfate, and polyglycol ether.

[0015] Preferably, the photocuring agent is a cationic curing agent.

[0016] Preferably, the sensitizer is a free radical photoinitiator.

[0017] A method for preparing a low shrinkage modified photocurable resin comprises the following steps:

[0018] Step 1: Heat the reactor to 60°C, then add silicone-modified epoxy resin, homemade hyperbranched epoxy, active diluent, filler and anti-settling agent and stir, stir for 1 hour and then cool to 30°C to prepare the main agent;

[0019] Step 2: Add the photocuring agent and sensitizer into the reaction kettle in proportion and mix and stir for 0.5h to obtain the curing agent after mixing evenly;

[0020] Step 3: Add the prepared main agent and curing agent into a mixer and stir for 30 minutes to obtain a light-curing epoxy adhesive.

[0021] A method for preparing a hyperbranched epoxy resin comprises the following steps: placing ethylenediamine in a beaker, heating the beaker in an oil bath at 90°C, adding bismaleimide styrene resin, stirring evenly, performing a prepolymerization reaction at 90-100°C for 15-20 minutes, adding preheated tetraglycidylamine epoxy resin after the reaction, stirring evenly to obtain a hyperbranched epoxy resin.

[0022] The present invention has the following beneficial effects:

[0023] The present invention adopts tetrafunctional organic silicon epoxy as the main body of the resin and self-made hyperbranched epoxy as the toughening agent, which can reduce the shrinkage rate of the resin and improve the toughness of the resin;

[0024] The present invention can prevent stratification and sedimentation and maintain better dimensional stability by adding a fumed silica suspension anti-settling agent;

[0025] The present invention can effectively reduce the shrinkage rate of the material, alleviate the deformation of the workpiece caused by shrinkage during the light curing process, and improve the forming accuracy of the workpiece by compounding the cationic iodonium salt curing agent with the sensitizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the synthetic reaction formula of hyperbranched epoxy AG80-MBMI. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0028] Specific implementation method 1: Combination Figure 1 The present embodiment is described as follows: a low shrinkage modified photocurable resin of the present embodiment, wherein the low shrinkage modified photocurable resin is composed of a main agent and a curing agent;

[0029] The mass ratio of the main agent to the curing agent is 100 parts: 3-10 parts;

[0030] The main agent is composed of 30-80 parts of organosilicon-modified epoxy resin, 0-30 parts of hyperbranched epoxy resin, 0-20 parts of active diluent, 0-40 parts of filler and 0-5 parts of anti-settling agent;

[0031] The curing agent consists of 1-5 parts of a photocuring agent and 2-5 parts of a sensitizer.

[0032] Specific implementation method 2: Combination Figure 1 The present embodiment is described. In the present embodiment, the low shrinkage modified photocurable resin, the silicone modified epoxy resin contains 2-4 epoxy groups.

[0033] The epoxy value of silicone modified epoxy resin is 0.5±0.05.

[0034] Specific implementation method three: Combination Figure 1 The present embodiment is described as a low shrinkage modified photocurable resin, wherein the active diluent is one of poly(ethylene glycol) diacrylate, monoepoxy acryl glycidyl ether, phenyl glycidyl ether, diepoxy ethylene glycol diglycidyl ether, resorcinol diglycidyl ether, butyl glycidyl ether, 1,4-butanediol diglycidyl ether, and polypropylene glycol diglycidyl ether.

[0035] Specific implementation method four: Combination Figure 1 The present embodiment is described as a low shrinkage modified photocurable resin, wherein the filler is one of silicon dioxide, titanium dioxide, and spherical aluminum oxide.

[0036] Specific implementation method five: Combination Figure 1 The present embodiment is described as a low shrinkage modified photocurable resin, wherein the anti-settling agent is one of suspended fumed silica, nonionic polyoxyethylene fatty amine, polyoxyethylene fatty alcohol sulfate, and polyglycol ether.

[0037] Specific implementation method six: Combination Figure 1 The present embodiment is described below. The present embodiment is a low shrinkage modified photocurable resin, and the photocuring agent is a cationic curing agent.

[0038] The photocuring agent is one of bis(4-tert-butylphenyl)iodonium hexafluorophosphate, 4-isobutylphenyl-4'-tolyliodonium hexafluorophosphate, isopropylferrocenium hexafluorophosphate, 4-(phenylthio)phenyldiphenylthiodonium hexafluorophosphate, diaryliodonium hexafluorophosphate, and diaryliodonium hexafluoroarsenate.

[0039] Specific implementation method seven: Combination Figure 1 This embodiment is described. This embodiment is a low shrinkage modified photocurable resin, and the sensitizer is a free radical photoinitiator.

[0040] The free radical photoinitiator is one of benzoin and its ethers, benzil dialkyl ketal and aromatic ketones.

[0041] The absorption peak of cationic curing agent is around 250, which is lower than that of ordinary photocuring agent, so it needs to be used with sensitizer. It has the characteristics of high reactivity, low volatility, low migration, low toxicity and low yellowing.

[0042] Specific implementation method eight: Combination Figure 1 The present embodiment is described. A method for preparing a low shrinkage modified photocurable resin in the present embodiment comprises the following steps:

[0043] Step 1: Heat the reactor to 60°C, then add silicone-modified epoxy resin, homemade hyperbranched epoxy, active diluent, filler and anti-settling agent and stir, stir for 1 hour and then cool to 30°C to prepare the main agent;

[0044] Step 2: Add the photocuring agent and sensitizer into the reaction kettle in proportion and mix and stir for 0.5h to obtain the curing agent after mixing evenly;

[0045] Step 3: Add the prepared main agent and curing agent into a mixer and stir for 30 minutes to obtain a light-curing epoxy adhesive.

[0046] Specific implementation method nine: Combination Figure 1 The present embodiment is described. A method for preparing a hyperbranched epoxy resin according to the present embodiment comprises the following steps: placing ethylenediamine in a beaker, heating it in an oil bath at 90°C, then adding bismaleimide styrene resin, stirring evenly, and prepolymerizing at 90-100°C for 15-20 minutes. After the reaction is completed, adding preheated tetraglycidylamine epoxy resin, stirring evenly to obtain a hyperbranched epoxy resin.

[0047] The molecular weight of the hyperbranched epoxy resin is 1700-2300 g / mol; the viscosity of the hyperbranched polyester is 80-120 mPa.s; and the branching degree of the hyperbranched polymer is 0.5 mol / 100 g.

[0048] The hyperbranched epoxy resin is AG80-MBMI.

[0049] Example 1

[0050] Step 1: Heat the reactor to 60°C, then sequentially add 80g of tetrafunctional silicone-modified epoxy resin, 10g of homemade hyperbranched epoxy AG80-MBMI, 10g of active diluent poly(ethylene glycol) diacrylate, and 40g of filler spherical alumina into the reactor, stir for 1h, cool to 30°C, discharge, and obtain the main agent;

[0051] Step 2: Add 3g of bis(4-tert-butylphenyl)iodonium hexafluorophosphate photocuring agent and 3g of 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl-propionyl)-phenoxy]-phenyl]-2-methyl-propan-1-one sensitizer into a reaction kettle, stir for 0.5h to mix evenly, and discharge to obtain a curing agent;

[0052] Step 3: Mix the main agent and the curing agent in a weight ratio of 140:6, and stir for 30 minutes under a low-speed mixer to make the main agent and the curing agent evenly mixed to obtain a light-curing epoxy adhesive.

[0053] Embodiment 2

[0054] Step 1: Heat the reactor to 60°C, then sequentially add 80g of tetrafunctional organosilicon-modified epoxy resin, 10g of homemade hyperbranched epoxy AG80-MBMI, 10g of active diluent poly(ethylene glycol) diacrylate, and 5g of anti-settling agent fumed silica into the reactor, stir for 1h, cool to 30°C, discharge, and obtain the main agent;

[0055] Step 2: Add 3g of bis(4-tert-butylphenyl)iodonium hexafluorophosphate photocuring agent and 3g of 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl-propionyl)-phenoxy]-phenyl]-2-methyl-propan-1-one sensitizer into a reaction kettle, stir for 0.5h to mix evenly, and discharge to obtain a curing agent;

[0056] Step 3: Mix the main agent and the curing agent in a weight ratio of 105:6, and stir for 30 minutes under a low-speed mixer to mix the main agent and the curing agent evenly to obtain a light-curing epoxy adhesive.

[0057] Example 3

[0058] Step 1: Heat the reactor to 60°C, then sequentially add 80g of tetrafunctional organosilicon-modified epoxy resin, 10g of homemade hyperbranched epoxy AG80-MBMI, 10g of active diluent poly(ethylene glycol) diacrylate, 30g of filler spherical alumina, and 3g of anti-settling agent fumed silica into the reactor, stir for 1h, cool to 30°C, discharge, and obtain the main agent;

[0059] Step 2: Add 3 g of bis(4-tert-butylphenyl)iodonium hexafluorophosphate photocuring agent and 3 g of 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl-propionyl)-phenoxy]-phenyl]-2-methyl-propan-1-one sensitizer into a reaction kettle, stir for 0.5 h to mix evenly, and discharge to obtain a curing agent;

[0060] Step 3: Mix the main agent and the curing agent in a weight ratio of 133:6, and stir for 30 minutes under a low-speed mixer to make the main agent and the curing agent evenly mixed to obtain a light-curing epoxy adhesive.

[0061] Performance Testing

[0062] The three groups of low shrinkage photocurable resins obtained in Examples 1-3 were photocured under ultraviolet light with a wavelength of 365 nm, and the performance of the three groups of samples was tested. The test indicators are as follows:

[0063] Curing time: The prepared low shrinkage photocurable resin was coated on the release film with a thickness of 10 μm, and photocured under a 365 nm ultraviolet curing lamp. The time was measured with a stopwatch and the measurement unit was expressed in seconds. According to GB1728-79, the finger-touch dry method was used to determine whether the low shrinkage photocurable resin was completely cured. The curing time was measured 5 times and the average value was taken.

[0064] Volume shrinkage: It can be expressed as the percentage of the density difference before and after curing of the resin system to the density after curing. Use a vacuum density meter to measure the density of the resin before and after curing, and calculate the volume shrinkage of the cured resin according to the following formula:

[0065] Curing shrinkage = (1 – ρ before / ρ after) × 100%

[0066] In the formula: ρbefore is the density of the resin before curing, g / cm3; ρafter is the density of the resin after curing, g / cm3.

[0067] Elastic modulus: The elastic modulus of the specimen was determined by the tensile method. The CMT4202 electronic universal testing machine of MTSSANS was selected. The specimen was made into a dumbbell-shaped specimen through a mold. The test rate was 100 mm / min, the experimental temperature was 25°C, and 5 parallel specimens were tested. The elastic modulus of the specimen can be obtained according to the slope of the stress-strain curve.

[0068] The low shrinkage modified photocurable resins prepared in Examples 1-3 were subjected to performance comparison tests, and the test results are as follows:

[0069] Performance parameters Example 1 Example 2 Example 3 UV curing time(s) 5 4 5 Curing shrinkage (%) 1.38 0.83 0.45 Elastic modulus(GPa) 0.52 0.45 0.48

[0070] As can be seen from the above table: From the comparison results of Example 1 and Example 2, it can be seen that the anti-shrinkage effect of fumed silica is much better than that of spherical alumina. In Example 3, fumed silica and spherical alumina are compounded for use. From the results of curing shrinkage, it can be seen that the anti-shrinkage effect after compounding is the best. In addition, the elastic modulus of the epoxy adhesives prepared in Examples 1-3 is very low, indicating that the toughness is improved after the addition of hyperbranched epoxy.

[0071] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined, and those skilled in the art can exhaust all possibilities based on the mathematical knowledge of arrangement and combination. Therefore, the present invention will no longer describe the technical solutions after arrangement and combination one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present invention.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low shrinkage modified photocurable resin, characterized in that: The low shrinkage modified light-curable resin is composed of a main agent and a curing agent; The mass ratio of the main agent to the curing agent is 100 parts: 3-10 parts; The main agent is composed of 30-80 parts of organosilicon-modified epoxy resin, 0-30 parts of hyperbranched epoxy resin, 0-20 parts of active diluent, 0-40 parts of filler and 0-5 parts of anti-settling agent; The curing agent consists of 1-5 parts of a photocuring agent and 2-5 parts of a sensitizer.

2. The low shrinkage modified photocurable resin according to claim 1, characterized in that: Silicone-modified epoxy resin contains 2-4 epoxy groups.

3. The low shrinkage modified photocurable resin according to claim 1, characterized in that: The active diluent is one of poly(ethylene glycol) diacrylate, monoepoxy propylene glycidyl ether, phenyl glycidyl ether, diepoxy ethylene glycol diglycidyl ether, resorcinol diglycidyl ether, butyl glycidyl ether, 1,4-butanediol diglycidyl ether, and polypropylene glycol diglycidyl ether.

4. The low shrinkage modified photocurable resin according to claim 1, characterized in that: The filler is one of silicon dioxide, titanium dioxide and spherical alumina.

5. The low shrinkage modified photocurable resin according to claim 1, characterized in that: The anti-settling agent is one of suspended fumed silica, non-ionic polyoxyethylene fatty amine, polyoxyethylene fatty alcohol sulfate, and polyglycol ether.

6. The low shrinkage modified photocurable resin according to claim 1, characterized in that: The photocuring agent is a cationic curing agent.

7. The low shrinkage modified photocurable resin according to claim 1, characterized in that: The sensitizer is a free radical photoinitiator.

8. A method for preparing a low shrinkage modified photocurable resin, characterized in that: The steps include: Step 1: Heat the reactor to 60°C, then add silicone-modified epoxy resin, homemade hyperbranched epoxy, active diluent, filler and anti-settling agent and stir, stir for 1 hour and then cool to 30°C to prepare the main agent; Step 2: Add the photocuring agent and sensitizer into the reaction kettle in proportion and mix and stir for 0.5h to obtain the curing agent after mixing evenly; Step 3: Add the prepared main agent and curing agent into a mixer and stir for 30 minutes to obtain a light-curing epoxy adhesive.

9. A method for preparing a hyperbranched epoxy resin, characterized in that: The method comprises the following steps: placing ethylenediamine in a beaker, heating the beaker in an oil bath at 90°C, adding bismaleimide styrene resin, stirring evenly, carrying out a prepolymerization reaction at 90-100°C for 15-20 minutes, adding preheated tetraglycidylamine epoxy resin after the reaction, stirring evenly to obtain a hyperbranched epoxy resin.

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