Resin composition, high pressure mold and preparation method thereof

Abstract

The present application relates to the field of mold making technology, and in particular to a resin composition, a high-pressure mold and a preparation method thereof, which can shorten the stirring time and enable epoxy resin and silica sand to be fully mixed, without strictly controlling the temperature of the mixed slurry, greatly improving the temperature compatibility of curing. At the same time, the silica sand solution and the epoxy resin can undergo a curing reaction at a relatively low temperature, which can reduce the problems of poor fluidity of the mixed slurry and cracking of the cast body caused by excessive temperature. A resin composition comprises: epoxy resin, epoxy resin curing agent, silica sand and water; wherein the epoxy resin comprises: bisphenol epichlorohydrin resin; the epoxy resin curing agent comprises a first curing agent and a second curing agent, the first curing agent comprises: 2,4,6-tris(dimethylaminomethyl)phenol, the second curing agent comprises: metaphenylenediamine curing agent and a modifier of the metaphenylenediamine curing agent, the modifier comprising: phenol.

Description

Technical Field

[0001] The present application relates to the technical field of mold making, and in particular to a resin composition, a high-pressure mold and a preparation method thereof. Background Art

[0002] At present, some ceramic products, such as sanitary ceramic toilets, are mainly made by high-pressure molds. The high-pressure molds are mainly made by mixing silica sand, epoxy resin and epoxy resin curing agent. The advantage is that the material consumption is small and the cost is low.

[0003] However, the current silica sand, epoxy resin and epoxy resin curing agent have problems such as poor compatibility, long stirring time and uneven mixing when mixed. In addition, during the reaction process, the temperature of the mixed slurry needs to be strictly controlled at 30°C~32°C. If the temperature is too high, such as exceeding 33°C, the epoxy resin will shrink too quickly and cause the casting to crack. Summary of the invention

[0004] Based on this, some embodiments of the present application provide a resin composition, which can be used for slurry preparation and mixing at room temperature such as 25°C~30°C, has good compatibility during mixing, can shorten the mixing time, and can be fully mixed. At the same time, the silica sand solution and the epoxy resin can undergo a curing reaction at a relatively low temperature, which can reduce the problems of poor fluidity of the mixed slurry and cracking of the casting body caused by excessive temperature, and there is no need to strictly control the temperature of the mixed slurry, which greatly improves the temperature compatibility of the curing. In addition, some embodiments of the present application also provide a method for preparing a high-pressure mold using the resin composition, and a high-pressure mold prepared by the method.

[0005] In a first aspect, a resin composition is provided, the resin composition comprising: an epoxy resin, an epoxy resin curing agent, silica sand and water;

[0006] Among them, the epoxy resin includes: bisphenol epichlorohydrin resin; the epoxy resin curing agent includes a first curing agent and a second curing agent, the first curing agent includes: 2,4,6-tris(dimethylaminomethyl)phenol, the second curing agent includes: m-phenylenediamine curing agent and a modifier of m-phenylenediamine curing agent, the modifier includes: phenol.

[0007] Optionally, based on 100 parts by total weight of the resin composition, the epoxy resin is 17 to 21 parts, the first curing agent is 2 to 4 parts, the m-phenylenediamine curing agent is 7 to 11 parts, the modifier is 0.7 to 1.3 parts, the silica sand is 41 to 45 parts, and the water is 23 to 27 parts.

[0008] In a second aspect, a method for preparing a high-pressure mold is provided, comprising:

[0009] Providing the resin composition as described in the first aspect;

[0010] Mixing the silica sand and water in the resin composition to prepare a silica sand solution by stirring;

[0011] Mixing the silica sand solution with the first curing agent in the resin composition and stirring for a first preset time to obtain a first component;

[0012] Mixing the epoxy resin, the m-phenylenediamine curing agent and the modifier in the resin composition and stirring for a second preset time to obtain a second component;

[0013] Mixing the first component and the second component and stirring for a third preset time to obtain a casting slurry;

[0014] Casting and curing the casting slurry to obtain the high-pressure mold;

[0015] Optionally, the temperature of pouring and curing and drying is 30° C. to 36° C., and the time of curing and drying is 24 h to 36 h.

[0016] Optionally, the mixing of silica sand and water in the resin composition and preparing a silica sand solution by stirring comprises:

[0017] The water is stirred at a first rotation speed, and the silica sand is added to the water under stirring for a first time period;

[0018] After adjusting the stirring speed to a second speed, the silica sand and the water are continuously stirred for a second time to obtain a mixed liquid of water and silica sand; wherein the second speed is greater than the first speed;

[0019] The mixed solution of water and silica sand is screened, and the screened mixed solution is continuously stirred at the second rotation speed for a third time to obtain the silica sand solution.

[0020] Optionally, the preparation method satisfies at least one of the following conditions:

[0021] (1) The first speed is 70 r / min~100 r / min, and the second speed is 190 r / min~260 r / min;

[0022] (2) The mesh size of the filter screen used for the screening is 40-60 mesh;

[0023] (3) The first duration is 10 minutes to 20 minutes;

[0024] (4) The second duration is 45 minutes to 60 minutes, and the third duration is 45 minutes to 60 minutes.

[0025] Optionally, the step of mixing the silica sand solution with the first curing agent in the resin composition and stirring for a first preset time to obtain a first component is carried out simultaneously with the step of mixing the epoxy resin, the m-phenylenediamine curing agent and the modifier in the resin composition and stirring for a second preset time to obtain a second component.

[0026] Optionally, the first preset time is 10 min to 20 min, and the second preset time is 3 min to 5 min.

[0027] Optionally, mixing the first component and the second component and stirring for a third preset time to obtain a casting slurry comprises:

[0028] Pour the second component into the first component, and use a scraper to scrape the remaining second component into the first component;

[0029] Stirring the first component and the second component at a third rotation speed for a third preset time to obtain the casting slurry;

[0030] Among them, the third rotation speed is 580r / min~650r / min, and the third preset time is 6min~8min.

[0031] In a third aspect, a high-pressure mold is provided, which is prepared using the preparation method described in the second aspect.

[0032] The beneficial effects of the above-mentioned resin composition, high-pressure mold and preparation method thereof are as follows:

[0033] Through the synergistic effect between the components in the resin composition, the compatibility of silica sand and epoxy resin can be improved, thereby shortening the stirring time and improving the mixing uniformity. At the same time, the resin composition can also maintain a low curing temperature. During the curing reaction process, low-temperature rapid curing can be achieved, avoiding the problem of excessive shrinkage of the epoxy resin caused by excessively high temperature and reducing cracking of the casting body.

[0034] Furthermore, the synergistic effect between the components in the resin composition can also improve the shrinkage resistance, bonding performance, heat resistance and chemical corrosion resistance of the epoxy resin material itself, and can improve the hardness and toughness of the cured product. Therefore, the resin composition has good comprehensive performance and can solve the technical problems in the related art that when silica sand, epoxy resin and epoxy resin curing agent are mixed, there is poor compatibility, long stirring time, uneven mixing, and the temperature of the mixed slurry needs to be strictly controlled. If the temperature is too high, the epoxy resin will shrink too quickly and cause cracking of the casting body. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic flow chart of a method for preparing a high-pressure mold provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0037] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as an open, inclusive meaning, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "exemplarily" or "some examples" and the like are intended to indicate that specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0038] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of layers and regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include shape deviations due to, for example, manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0039] In this document, "for example", "such as", "example", "for example", etc. are used for descriptive purposes, indicating that the previous and subsequent different technical solutions are related in terms of the content covered, but should not be understood as limiting the previous technical solution, nor can they be understood as limiting the scope of protection of this document. In this document, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0040] In this article, "optionally", "optional", and "optional" mean optional, that is, any one of the two parallel options of "yes" or "no". If there are multiple "options" in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "option" is independent.

[0041] Herein, descriptions such as "optionally contain", "optionally include", etc., mean "contain or not contain". "Optional component X" means component X exists or does not exist, or means containing or not containing the component X.

[0042] In this document, the terms "first", "second", etc. in "the first aspect", "the second aspect", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features.

[0043] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0045] In this article, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0046] In this document, "at least one" means more than one, such as one, two and more than two. "Multiple" or "several" means at least two, such as two, three, etc.

[0047] Herein, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​within the numerical interval is considered to be continuous and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when a numerical interval only refers to integers within the numerical interval, including the two endpoint integers of the numerical range, and each integer between the two endpoints, is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0048] In this article, when it comes to percentage concentration, unless otherwise specified, it refers to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of the component.

[0049] In this article, if there are multiple steps involved in the method flow, unless there is a clear different description in this article, there is no strict order restriction for the execution of these steps, and they can be executed in other orders than described. Moreover, any step can include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn, alternating or simultaneously with other steps or parts of sub-steps or stages of other steps.

[0050] In view of the technical problems in the related art that silica sand, epoxy resin and epoxy resin curing agent have poor compatibility, long stirring time, uneven mixing, and the temperature of the mixed slurry needs to be strictly controlled. If the temperature is too high, the epoxy resin will shrink too quickly and cause the casting body to crack, the specific implementation method of the present application is described as follows:

[0051] In a first aspect, some embodiments of the present application provide a resin composition, comprising: an epoxy resin, an epoxy resin curing agent, silica sand and water; wherein the epoxy resin comprises: bisphenol epichlorohydrin resin; the epoxy resin curing agent comprises a first curing agent and a second curing agent, the first curing agent comprises: 2,4,6-tris(dimethylaminomethyl)phenol, the second curing agent comprises: an m-phenylenediamine curing agent and a modifier of the m-phenylenediamine curing agent, the modifier comprising: phenol.

[0052] Among them, bisphenol epichlorohydrin resin is a bisphenol A type epoxy resin, which is formed by condensation of bisphenol A (Bisphenol- A) and epichlorohydrin (Epichlorohydrin) under the action of alkali. Its chemical structure contains multiple epoxy groups, which are the active sites where curing reactions can occur.

[0053] Bisphenol epichlorohydrin resin has good adhesion to a variety of materials. It can bond metals (such as aluminum, steel, etc.), ceramics, glass and wood, etc. This is because the epoxy groups in the resin can react chemically with the active groups on the surface of the bonded material (such as hydroxyl, carboxyl, etc.) to form chemical bonds. At the same time, the resin will shrink to a certain extent during the curing process, making it in close contact with the bonded material, thereby enhancing the bonding effect.

[0054] In addition, the cured bisphenol epichlorohydrin resin has high strength and hardness, can withstand certain tensile, compressive and bending stresses, and has good chemical stability and can withstand corrosion from a variety of chemical substances.

[0055] 2,4,6-Tris(dimethylaminomethyl)phenol (DMP-30) is an effective curing accelerator and can be used as a curing agent for epoxy resin in a mixed system of epoxy resin and amine curing agents. When epoxy resin reacts with amine curing agents (such as aromatic amines, etc.), DMP-30 forms hydrogen bonds or other intermolecular forces with amine curing agents to increase the activity of the curing agent, thereby accelerating the curing reaction and shortening the curing time.

[0056] In addition, the addition of DMP-30 can also improve the performance of epoxy resin cured products. For example, it can make the cured epoxy resin have better toughness and impact resistance. This is because DMP-30 participates in the cross-linking reaction during the curing process, making the molecular structure of the cured product more uniform and regular, reducing the phenomenon of internal stress concentration, thereby improving the toughness of the material.

[0057] The m-phenylenediamine curing agent has an aromatic structure. When used as a curing agent for epoxy resin, it can improve the structural stability of the cured product in a high temperature environment, thereby improving the thermal stability of the cured product.

[0058] In addition, the m-phenylenediamine curing agent can form a tight three-dimensional network structure with the epoxy resin, thereby improving the hardness and impact resistance of the cured product. At the same time, the m-phenylenediamine curing agent can also improve the acid and alkali corrosion resistance of the cured product.

[0059] When the m-phenylenediamine curing agent is used to cure epoxy resin, the reaction is slow at room temperature and the temperature needs to be appropriately increased to significantly accelerate the curing reaction speed.

[0060] The modifier includes phenol. When it is used to modify the m-phenylenediamine curing agent, it can react with the m-phenylenediamine curing agent to generate a mixed phenol modified m-phenylenediamine resin curing agent. The m-phenylenediamine curing agent modified by the modifier has better low-temperature rapid curing performance and plasticity, can reduce the curing reaction temperature, avoid the problems of resin viscosity and non-fluidity and casting body cracking during actual operation caused by rapid reaction, and at the same time, the addition of the modifier can improve the heat resistance and chemical corrosion resistance of the cured product. In addition, the modifier can also be used as a catalyst to promote the curing reaction, further reduce the defects such as curing cracking, and at the same time, the modifier can also improve the physical properties of the cured product, such as improving the hardness of the cured product.

[0061] In summary, in the resin composition provided in the embodiment of the present application, the compatibility of silica sand and epoxy resin can be improved through the synergistic effect between the components in the resin composition, thereby shortening the stirring time and improving the mixing uniformity. At the same time, the resin composition can also maintain a low curing temperature. During the curing reaction, low-temperature rapid curing can be achieved, avoiding the problem of excessive shrinkage of the epoxy resin caused by excessively high temperature, and reducing the cracking of the cast body. Furthermore, the synergistic effect between the components in the resin composition can also improve the shrinkage resistance, bonding performance, heat resistance and chemical corrosion resistance of the epoxy resin material itself, and can improve the hardness and toughness of the cured product. Therefore, the resin composition has good comprehensive performance, which can solve the technical problems of poor compatibility, long stirring time, uneven mixing, and the need to strictly control the temperature of the mixed slurry when mixing silica sand, epoxy resin and epoxy resin curing agent in the related art. If the temperature is too high, the epoxy resin will shrink too fast and cause the cast body to crack.

[0062] In some embodiments, based on 100 parts by total weight of the resin composition, the epoxy resin is 17 to 21 parts, the first curing agent is 2 to 4 parts, the m-phenylenediamine curing agent is 7 to 11 parts, the modifier is 0.7 to 1.3 parts, the silica sand is 41 to 45 parts, and the water is 23 to 27 parts.

[0063] In these embodiments, by controlling the weight of each component within the above range, the fluidity of the mixed slurry during the mixing and stirring process can be improved, which is convenient for pouring. After pouring, the solidified surface will not crack, and the flexural strength of the cast body after solidification is high, which has good comprehensive performance.

[0064] In a second aspect, some embodiments of the present application provide a method for preparing a high-pressure mold, such as Figure 1 As shown, the preparation method includes the following steps S11 to S16:

[0065] S11, providing the resin composition as described in the first aspect;

[0066] The resin composition comprises: epoxy resin, epoxy resin curing agent, silica sand and water; wherein the epoxy resin comprises: bisphenol epichlorohydrin resin; the epoxy resin curing agent comprises a first curing agent and a second curing agent, the first curing agent comprises: 2,4,6-tris(dimethylaminomethyl)phenol, the second curing agent comprises: metaphenylenediamine curing agent and a modifier of the metaphenylenediamine curing agent, and the modifier comprises: phenol.

[0067] S12, mixing the silica sand and water in the resin composition, and preparing a silica sand solution by stirring;

[0068] Among them, the silica sand has a regular tetrahedral crystal structure, is slightly soluble in water, and does not react with water. After it is mixed with water and stirred, the water molecules are wrapped by the silica sand particles, and tiny passages are formed between the water molecules, establishing a skeleton for the preparation of porous resin.

[0069] The stirring time of the silica sand solution is related to its compatibility with the epoxy resin and whether it is easy to stir evenly. If the silica sand solution has poor compatibility with the epoxy resin and is not easy to stir evenly, a longer stirring time is required to avoid subsequent resin hydration and inability to use; if the silica sand solution has good compatibility with the epoxy resin and is easy to stir evenly, a shorter stirring time is required to improve the mixing uniformity, maintain good fluidity of the mixed slurry, and facilitate casting.

[0070] S13, mixing the silica sand solution with the first curing agent in the resin composition and stirring for a first preset time to obtain a first component;

[0071] By mixing the silica sand solution with the first curing agent in the resin composition and stirring for a first preset time, the first curing agent can be evenly mixed with the silica sand solution first, which is convenient for subsequent rapid and uniform mixing with the epoxy resin and the m-phenylenediamine curing agent, so that it is convenient for the first curing agent to quickly play an auxiliary curing role when it is evenly mixed with the epoxy resin and the m-phenylenediamine curing agent, thereby improving the curing effect and reducing the problem of uneven curing reaction.

[0072] S14, mixing the epoxy resin, the m-phenylenediamine curing agent and the modifier in the resin composition and stirring for a second preset time to obtain a second component;

[0073] By mixing and stirring the epoxy resin, m-phenylenediamine curing agent and modifier in the resin composition for a second preset time, utilizing the characteristics that the m-phenylenediamine curing agent and the epoxy resin react slowly at room temperature and need to increase the temperature appropriately to significantly accelerate the curing reaction speed, and the modifier can reduce the curing reaction temperature, the epoxy resin, m-phenylenediamine curing agent and modifier can be kept mixed at a relatively low temperature without a violent curing reaction, maintaining good fluidity of the mixed slurry, facilitating the subsequent mixing with the first component and maintaining fluidity during pouring, thereby reserving a longer time for the subsequent mixing with the first component and pouring, avoiding disadvantages such as excessive temperature caused by too rapid reaction, excessive shrinkage of the epoxy resin and poor fluidity.

[0074] S15, mixing the first component and the second component and stirring for a third preset time to obtain a casting slurry;

[0075] After preparing the first component and the second component, by mixing and stirring the first component and the second component for a third preset time, the first component and the second component can be timely prepared into a casting slurry with good fluidity, thereby facilitating a low-temperature curing reaction of the epoxy resin and silica sand solution in the presence of the first curing agent and the second curing agent.

[0076] In this process, under the synergistic effect of the epoxy resin, the first curing agent and the second curing agent, the compatibility and bonding properties of the epoxy resin and the silica sand solution can be effectively improved, and the epoxy resin and the silica sand solution can be quickly cured at a lower temperature, reducing the shrinkage of the epoxy resin caused by excessive temperature and excessive shrinkage stress unique to the epoxy resin material itself.

[0077] S16, pouring and curing the pouring slurry to obtain a high-pressure mold.

[0078] In the preparation method of the high-pressure mold provided in the embodiment of the present application, a silica sand solution is prepared, and then the silica sand solution is mixed with the first curing agent in the resin composition and stirred for a first preset time to obtain a first component, and the epoxy resin, metaphenylenediamine curing agent and modifier in the resin composition are mixed and stirred for a second preset time to obtain a second component. The first curing agent and the second curing agent can be added to the silica sand solution and the epoxy resin respectively by utilizing their respective characteristics, so that the first curing agent and the second curing agent can be quickly mixed with the silica sand solution and the epoxy resin when the first component and the second component are mixed, and the curing reaction temperature can be reduced as much as possible to maintain good fluidity of the first component and the second component, thereby reducing problems such as poor mixing and casting caused by excessive temperature and poor fluidity of the first component and the second component.

[0079] After the first component and the second component are mixed, the compatibility and mixing uniformity of the silica sand solution and the epoxy resin can be improved under the synergistic effect of the first curing agent and the second curing agent, and the silica sand solution and the epoxy resin can undergo a curing reaction at a relatively low temperature, such as 30°C to 36°C, thereby reducing the problems of poor fluidity of the mixed slurry and cracking of the casting body caused by excessively high temperature, and there is no need to control the temperature at 30°C to 32°C, thereby greatly improving the temperature compatibility of the curing.

[0080] By selecting a suitable epoxy resin, since the epoxy resin has good bonding properties, the shear stress formed at the interface between the silica sand and the epoxy resin due to shrinkage stress can be reduced during the curing process, thereby reducing the cracking of the cast body. At the same time, under the synergistic effect of the first curing agent and the second curing agent, when the epoxy resin is cured, the shrinkage stress of the epoxy resin can be further reduced, thereby further reducing the problem of excessive shrinkage of the epoxy resin and further reducing the cracking of the cast body.

[0081] In some embodiments, in S16, the temperature for pouring and curing and drying is 30° C. to 36° C., and the time for curing and drying is 24 h to 36 h.

[0082] In these embodiments, during the pouring and curing drying process, the pouring and curing of the high-pressure mold can be completed by controlling the pouring and curing drying temperature to 30°C ~ 36°C. There is no need to limit the curing temperature to between 30°C ~ 32°C. Even at higher temperatures, the pouring body will not crack, etc., which greatly improves the temperature compatibility of epoxy resin curing.

[0083] In some embodiments, S12, mixing the silica sand in the resin composition with water and preparing a silica sand solution by stirring, may include:

[0084] S121, stirring the water at a first speed, adding silica sand to the water under stirring, and stirring for a first time;

[0085] S122, after adjusting the stirring speed to a second speed, continue stirring the silica sand and water for a second stirring time, the second speed being greater than the first speed;

[0086] S123, sieving the mixed solution, and continuing to stir the sieved mixed solution at the second rotation speed for a third time to obtain a silica sand solution.

[0087] In these embodiments, by adding silica sand to water at a first rotational speed, the two can be mixed at a lower rotational speed. Then, by adjusting the stirring speed to a second rotational speed and stirring the silica sand and water at the second rotational speed for a second time, the silica sand and water can be fully mixed at a higher rotational speed. Subsequently, by screening the mixed solution and continuing to stir the screened mixed solution at the second rotational speed for a third time, the silica sand particles in the silica sand solution can be maintained within a certain range, and the mixing effect of the silica sand and water can be further improved.

[0088] In some embodiments, the first rotational speed is 70 r / min-100 r / min, and the second rotational speed is 190 r / min-260 r / min.

[0089] In some embodiments, the first duration is 10 minutes to 20 minutes.

[0090] In some embodiments, the second duration is 45 min to 60 min, and the third duration is 45 min to 60 min.

[0091] In these embodiments, the silica sand and water can be fully mixed when the second and third time periods are shorter, and the compatibility of the silica sand solution and the epoxy resin can be improved. Therefore, compared with the related art in which silica sand and water need to be stirred for more than 4 hours, the stirring time of silica sand and water can be shortened and the efficiency can be improved.

[0092] In some embodiments, the mesh size of the filter screen used for screening is 40-60 mesh.

[0093] In these embodiments, the silica sand can be kept at a certain particle size, so as to facilitate mixing of the silica sand solution with the epoxy resin to prepare a cured product with excellent performance.

[0094] In some embodiments, the step of mixing the silica sand solution with the first curing agent in the resin composition and stirring for a first preset time to obtain the first component is performed simultaneously with the step of mixing the epoxy resin, the m-phenylenediamine curing agent and the modifier in the resin composition and stirring for a second preset time to obtain the second component.

[0095] In these embodiments, the mixing can be further accelerated, the epoxy resin and the silica sand solution can be kept as fluid as possible before and after mixing, the mixing uniformity of the epoxy resin and the silica sand solution can be improved, and the poor curing caused by uneven mixing can be reduced.

[0096] In some embodiments, the first preset time is 10 min to 20 min, and the second preset time is 3 min to 5 min.

[0097] In some embodiments, the first component and the second component are mixed and stirred for a third preset time to obtain a casting slurry, comprising:

[0098] Pour the second component into the first component, and use a scraper to scrape the remaining second component into the first component;

[0099] The first component and the second component are stirred at a third rotating speed for a third preset time to obtain a casting slurry.

[0100] In these embodiments, by pouring the second component into the first component and using a scraper to scrape the remaining second component into the first component, the second component and the first component can be fully utilized as much as possible, reducing material losses caused by the mixing process, and the components can be mixed in a predetermined ratio, thereby improving the accuracy of the distribution ratio of each component in the casting slurry.

[0101] In some embodiments, the third rotation speed is 580 r / min~650 r / min, and the third preset time is 6min~8min.

[0102] In these embodiments, the first component and the second component can be fully mixed as quickly as possible at a higher rotation speed, and the silica sand and the epoxy resin can be fully mixed and poured in a shorter time, so that the casting body can be cured at a lower temperature, avoiding the first component and the second component being mixed and cured for a long time to release heat and deteriorate fluidity, which is not conducive to pouring, and the first component and the second component being mixed and cured for a long time to release heat, resulting in excessively high temperature, thereby causing the casting body to crack.

[0103] In a third aspect, some embodiments of the present application provide a high-pressure mold, which is prepared by the preparation method described in the second aspect.

[0104] Among them, the high-pressure mold can be prepared at a lower curing temperature such as 30°C~36°C, and will not crack at above 33°C, with a high yield rate. In addition, the high-pressure mold is formulated with a specific type of epoxy resin and silica sand, and a first curing agent and a second curing agent are used as epoxy resin curing agents, which can effectively improve the mixing uniformity of the epoxy resin and silica sand, thereby improving the curing uniformity of the casting, improving the curing effect, and reducing the cracking of the casting during the curing process. At the same time, the high-pressure mold prepared by the specific type of epoxy resin and silica sand in the presence of the first curing agent and the second curing agent also has high hardness and toughness, which can meet the current application requirements for high-pressure molds.

[0105] In order to objectively evaluate the technical effects of the embodiments of the present application, the present application will be described in detail and exemplarily through the following embodiments.

[0106] In the following examples, all raw materials can be purchased from commercial sources, and in order to maintain the reliability of the experiments, the raw materials used in the following examples all have the same physical and chemical parameters or are prepared by the same processing method.

[0107] When the resin composition is prepared into a high-pressure mold, the resin composition includes the following six components:

[0108] 1. Water;

[0109] 2. Component A: silica sand powder, the purity of silicon dioxide is 93%~96%;

[0110] 3. Component B: 2,4,6-tris(dimethylaminomethyl)phenol, also known as the first curing agent;

[0111] 4. Component C: bisphenol epichlorohydrin resin, also known as epoxy resin;

[0112] 5. Component D: m-phenylenediamine;

[0113] 6. Component E: phenol, also known as modifier.

[0114] Before setting the examples, the addition ratios of component B, component C, component D and component E were determined by the following test scheme:

[0115] Experimental plan 1

[0116] Component C, component D and component E were mixed and tested to observe the intensity of the reaction between resin epichlorohydrin and m-xylenediamine. Combined with the stirring and pouring requirements during the preparation of the high-pressure mold, the addition ratio of component E (phenol) was determined. The specific test results are shown in Table 1 below:

[0117] Table 1

[0118]

[0119] Experimental plan 2

[0120] According to the test results of test scheme 1, the amount of phenol added was controlled to fluctuate between 50g and 70g, and three groups of different addition amounts were set to repeat the above test scheme 1 to determine the amount of phenol added that best meets the requirements of high-pressure mold preparation. The test results are shown in Table 2 below:

[0121] Table 2

[0122]

[0123] According to the test results, it is determined that the curing time and effect when the addition amount of phenol is 55g are most in line with the requirements of high-pressure mold making.

[0124] Experimental plan 3

[0125] When the addition ratio of phenol in the epoxy resin is determined, component B (2,4,6-tris (dimethylaminomethyl) phenol) is added, and the intensity of the reaction between m-xylylenediamine and epoxy resin in the presence of component B (2,4,6-tris (dimethylaminomethyl) phenol) and phenol is observed. In combination with the stirring and pouring requirements during the preparation of the high-pressure mold, the addition ratio of component B (2,4,6-tris (dimethylaminomethyl) phenol) is determined. The test results are shown in Table 3 below:

[0126] Table 3

[0127]

[0128] According to the test results, it was determined that when the addition amount of component B (2,4,6-tris(dimethylaminomethyl)phenol) was 150g~160g, the curing time and effect met the requirements of high-pressure mold production, and the middle value of 155g was taken as the optimal addition amount to calculate the optimal addition ratio.

[0129] The addition ratios of component A, component B, component C, component D, component E and water are adjusted to be different to obtain Examples 1 to 10. The specific preparation methods of Examples 1 to 10 are as follows:

[0130] (1) Take a mixing barrel X, weigh water according to a certain ratio, put the mixing barrel into a dispersing mixer, adjust the speed to 85r / min and stir slowly, and add the weighed component A to the water. After all the components are added, stir slowly for 10 minutes, and then adjust the speed to 200r / min to fully mix and disperse the silica sand powder in the water to form a stable suspension. After stirring for 60 minutes, filter it with a 60-mesh filter screen and stir for another 60 minutes;

[0131] (2) After stirring component A and water for 120 minutes, weigh enough component B, add it and stir for about 10 minutes; at the same time, take another mixing bucket Y, weigh and add enough components C, D and E according to the ratio, use a disperser mixer for 4 minutes, and stir until the color is uniform and there is no variegated color;

[0132] (3) Pour the resin in barrel Y into barrel X. Use a plastic scraper to scrape the remaining resin on the inner wall of barrel Y into barrel X. Adjust the speed of the mixer in barrel X to 600 r / min and stir rapidly for 7 minutes. After about 10 to 15 minutes of stirring, the resin has good fluidity and can be poured.

[0133] (4) After stirring, transfer the X barrel of resin to the casting chamber and inject it into the prepared mold. The casting chamber is kept at a constant temperature of 35°C and cured for 25 hours. It is forbidden to move the mold during the curing period.

[0134] Among them, in Examples 1 to 10, the reaction results of the components in each example with different mass proportions are shown in Table 4 below:

[0135] Table 4

[0136]

[0137]

[0138] In Table 4, the flexural strength is tested by using an ADS-X universal testing machine. The test specimen is a cast and cured test strip of 10 mm (thickness) × 11 mm (width) × 150 mm (length). The loading speed of the ADS-X universal testing machine is set to 3 mm / min until the specimen breaks. The ADS-X universal testing machine outputs the corresponding flexural strength.

[0139] It can be seen from Table 4 that when the mass proportion of water is 23%~27%, the mass proportion of component A is 41%~45%, the mass proportion of component B is 2%~4%, the mass proportion of component C is 17%~21%, the mass proportion of component D is 7%~11%, and the mass proportion of component E is 0.7%~1.3%, normal pouring and curing can be achieved, and no cracks occur on the surface of the cured product, and the flexural strength can reach more than 5Mpa.

[0140] By comparing Example 1 and Example 2, it can be seen that when the amount of silica sand powder is 45%, if the amount of water used is less than 23%, the silica sand resin mixture may have poor fluidity, which is not conducive to pouring, and the number of bubbles on the surface of the solidified material after pouring increases; when the amount of silica sand powder is 41%, if the amount of water used is greater than 27%, there may be a problem of too fast flow and inability to cast and form, and at the same time, the flexural strength of the solidified material will be further reduced.

[0141] By comparing Example 3 and Example 4, it can be seen that when the usage of the first curing agent is 2% to 4%, the initial setting time requirement can be met. If the usage of the first curing agent is further reduced to less than 2%, the initial setting time will be extended, resulting in dark cracks in the silica sand resin due to the difference in internal and external moisture. If the usage of the first curing agent is further increased to more than 4%, the initial setting time will be too short, resulting in a reduction in the operation time of the overall casting process, resulting in excessive shrinkage and surface cracks.

[0142] Comparing Examples 5 to 8, it can be seen that as the ambient temperature changes, the amount of bisphenol epichlorohydrin resin and the amount of meta-xylylenediamine used can be adjusted to adjust the curing speed to meet the use requirements.

[0143] Comparing Examples 9 and 10, it can be seen that as the ambient temperature changes, the amount of phenol and m-xylylenediamine used can be adjusted to adjust the catalytic speed to meet the use requirements.

[0144] In comparison, the silica sand resin mixture provided in Examples 5 to 10 has better casting effect and flexural strength of the solidified product, and the proportion of each component can be adjusted according to the ambient temperature, which can more effectively adapt to the production and use requirements of the cast solidified product.

[0145] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0146] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A resin composition, characterized in that The resin composition comprises: epoxy resin, epoxy resin curing agent, silica sand and water; Among them, the epoxy resin includes: bisphenol epichlorohydrin resin; the epoxy resin curing agent includes a first curing agent and a second curing agent, the first curing agent includes: 2,4,6-tris (dimethylaminomethyl) phenol, the second curing agent includes: metaphenylenediamine curing agent and a modifier of the metaphenylenediamine curing agent, and the modifier includes: phenol.

2. The resin composition according to claim 1, characterized in that Based on 100 parts by total weight of the resin composition, the epoxy resin is 17 to 21 parts, the first curing agent is 2 to 4 parts, the m-phenylenediamine curing agent is 7 to 11 parts, the modifier is 0.7 to 1.3 parts, the silica sand is 41 to 45 parts, and the water is 23 to 27 parts.

3. A method for preparing a high pressure mold, characterized in that: include: Providing a resin composition according to any one of claims 1 to 2; Mixing the silica sand and water and preparing a silica sand solution by stirring; Mixing the silica sand solution with the first curing agent in the resin composition and stirring for a first preset time to obtain a first component; Mixing the epoxy resin, the m-phenylenediamine curing agent and the modifier in the resin composition and stirring for a second preset time to obtain a second component; Mixing the first component and the second component and stirring for a third preset time to obtain a casting slurry; The casting slurry is cast and cured and dried to obtain the high-pressure mold.

4. The preparation method according to claim 3, characterized in that: The temperature of pouring and curing and drying is 30° C. to 36° C., and the time of curing and drying is 24 h to 36 h.

5. The preparation method according to claim 3, characterized in that: The step of mixing the silica sand in the resin composition with water and preparing a silica sand solution by stirring comprises: The water is stirred at a first rotation speed, and the silica sand is added to the water under stirring for a first time period; After adjusting the stirring speed to a second speed, the silica sand and the water are continuously stirred for a second time to obtain a mixed liquid of water and silica sand; wherein the second speed is greater than the first speed; The mixed solution of water and silica sand is screened, and the screened mixed solution is continuously stirred at the second rotation speed for a third time to obtain the silica sand solution.

6. The preparation method according to claim 5, characterized in that: The preparation method satisfies at least one of the following conditions: (1) The first speed is 70 r / min~100 r / min, and the second speed is 190 r / min~260 r / min; (2) The mesh size of the filter screen used for the screening is 40-60 mesh; (3) The first duration is 10 minutes to 20 minutes; (4) The second duration is 45 minutes to 60 minutes, and the third duration is 45 minutes to 60 minutes.

7. The preparation method according to claim 3, characterized in that: The step of mixing the silica sand solution with the first curing agent in the resin composition and stirring for a first preset time to obtain the first component is simultaneously carried out with the step of mixing the epoxy resin, the m-phenylenediamine curing agent and the modifier and stirring for a second preset time to obtain the second component.

8. The preparation method according to claim 7, characterized in that: The first preset time is 10 min to 20 min, and the second preset time is 3 min to 5 min.

9. The preparation method according to claim 3, characterized in that: The first component and the second component are mixed and stirred for a third preset time to obtain a casting slurry, comprising: Pour the second component into the first component, and use a scraper to scrape the remaining second component into the first component; Stirring the first component and the second component at a third rotation speed for a third preset time to obtain the casting slurry; Among them, the third rotation speed is 580r / min~650r / min, and the third preset time is 6min~8min.

10. A high pressure mold, characterized in that: The method is prepared by any one of claims 3 to 9.

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