Composite modified water glass binder and method for preparing the same

Abstract

The application provides a water glass sand modifier, a water glass sand silane coupling agent and a modified water glass sand preparation method, and relates to the technical field of water glass sand.The water glass sand modifier provided by the application comprises titanium oxide powder, N-hydroxysuccinimide and trihydroxy polypropylene oxide ether.The application can make the adhesive film produce pores and gaps by volatilization and combustion at high temperature, thereby reducing the residual strength of the water glass sand, improving the collapsibility of the water glass sand and improving the utilization rate of the old sand.The silane coupling agent gamma-aminopropyl methyl diethoxysilane provided by the application can form Si-OH-containing oligomeric siloxane through dehydration and condensation after the alkoxy groups in the silane coupling agent are hydrolyzed, the oligomeric siloxane can form hydrogen bonds with the hydroxyl groups of the water glass, the water glass can form covalent bonds with water after drying, the oligomeric siloxane can form a protective layer on the surface of the silica gel colloidal particles, the growth of the crystal grains is hindered, and the adhesive strength of the water glass is enhanced.Meanwhile, the modified water glass binder has excellent performance, and the problems of low adhesive strength, poor water resistance and poor collapsibility of the traditional water glass binder are overcome.

Description

Technical Field

[0001] This invention relates to the field of water glass sand technology, and more specifically, to water glass sand modifiers, water glass sand silane coupling agents, modified water glass sand, and their preparation methods. Background Technology

[0002] Currently, water glass sand is widely used in my country's foundry industry. The water glass sand casting process, which uses water glass as a binder, has many advantages, including high strength, low cost, simple process, and environmental friendliness. Since its introduction into the foundry industry in the 1960s, it has been widely adopted by countries around the world.

[0003] However, water glass sand suffers from reduced bonding properties after prolonged storage, resulting in compromised strength, poor collapsibility, and difficulties in recycling and reuse, causing significant environmental pollution. For decades, this has been considered one of the world's major challenges in the foundry industry. Therefore, adopting a series of modification methods or techniques to enhance the comprehensive performance of water glass sand will facilitate its widespread application and help accelerate clean production and green manufacturing in my country's foundry industry.

[0004] Using water glass as a binder in casting sand presents challenges. Due to its inherent properties, sodium silicate, the active ingredient in water glass, melts at high temperatures and then solidifies again upon cooling, resulting in very high residual strength in the sand mold. This is highly detrimental to sand removal and cleaning of castings, and the excessive sodium ions on the surface of the old sand also severely hinder its recycling. Currently, most domestic methods involve adding modified water glass and modifiers to the original sand to reduce its residual strength, improve its collapsibility, and increase the recycling rate. In production, adding modifiers to water glass sand is the most convenient way to improve its performance and collapsibility. However, imported modifiers are still the most commonly used, despite their excellent modification effects, due to their exorbitant prices. Domestic research on water glass sand modifiers has also been conducted, including organic modifiers such as organic esters, inorganic powder modifiers such as alumina powder and inorganic salts, and composite modifiers. However, because most modifiers have limited applicability and cannot well adapt to the current casting environment in China, their overall effectiveness is not ideal. In view of this, the present invention is proposed to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a water glass sand modifier that can effectively improve the collapsibility of water glass sand, thereby addressing the technical problem of poor overall performance of existing water glass sand modifiers.

[0006] Another objective of this invention is to provide a silane coupling agent modified water glass sand with good collapsibility, low residual strength, and high recycling rate of old sand, so as to improve the technical problems of poor collapsibility, high residual strength, and low recycling rate of existing water glass sand.

[0007] The technical solution adopted in this invention is a composite modified water glass sand binder, which is composed of the following raw materials by weight percentage: 10% to 20% modifier, 60% to 70% water glass, and 10% to 30% silane coupling agent, with the total content of the above components being 100%.

[0008] The invention is further characterized in that,

[0009] The modifier is composed of the following raw materials by weight percentage: 35% to 45% titanium dioxide powder, 25% to 40% N-hydroxysuccinimide, and 15% to 40% trihydroxypolyoxypropylene ether, with the total content of the above components being 100%.

[0010] The invention is further characterized in that,

[0011] The silane coupling agent is made from the following raw materials by weight percentage: 30%–35% γ-aminopropylmethyldiethoxysilane, 35%–40% cyclohexylaminopropylsilane, and 25%–35% methyltrimethoxysilane, with the total content of the above components being 100%.

[0012] The method for preparing modified water glass sand used in this invention is specifically implemented according to the following steps:

[0013] Step 1: Mix all the raw materials of water glass sand silane coupling agent evenly according to the formula to obtain mixture A;

[0014] Step 2: After drying mixture A, mix it evenly with the original sand to obtain mixture B;

[0015] Step 3: Mix and heat the raw materials of the water glass sand modifier with water glass according to the formula amount, and after mixing evenly, add it to mixture B and mix evenly to obtain modified water glass sand.

[0016] The invention is further characterized in that,

[0017] In step 1, the time required to fully mix each raw material and mix it with the original sand is 2-3 minutes.

[0018] In step 2, the drying time is 5-8 hours and the temperature is 120-150℃.

[0019] In step 3, the raw materials of the modifier are stirred and heated according to the formula. After being mixed evenly, they are added to mixture B and mixed evenly for 4-5 minutes to obtain modified water glass sand.

[0020] The beneficial effects of this invention are:

[0021] (1) This invention provides a water glass sand modifier. Adding the water glass sand modifier to water glass sand can modify the water glass sand. The modifier includes titanium dioxide powder, N-hydroxysuccinimide, and trihydroxypolyoxypropylene ether. Its ability to volatilize and burn at high temperatures creates pores and gaps in the adhesive film, thereby reducing the residual strength of the water glass sand, improving its collapsibility, and increasing the utilization rate of old sand.

[0022] (2) This invention provides a water glass silane coupling agent. The alkoxy groups in γ-aminopropylmethyldiethoxysilane undergo hydrolysis and self-dehydration condensation to form Si-OH-containing oligomeric siloxanes. These oligomeric siloxanes form hydrogen bonds with the hydroxyl groups of water glass. After drying, they can form covalent bonds with the dehydrated water glass, coating the surface of the silica gel particles to form a protective layer. This hinders grain growth while enhancing the bonding strength of the water glass. In this invention, the modified water glass binder exhibits excellent performance, overcoming the problems of low bonding strength, poor water resistance, and poor collapsibility of traditional water glass.

[0023] (3) The present invention provides a modified water glass sand, which is obtained by mixing water glass sand with the above-mentioned water glass sand modifier and silane coupling agent in a specific ratio. The use of water glass sand modifier and silane coupling agent can significantly improve the bonding strength of modified water glass sand, greatly reduce the amount of modified glass sand added, and also effectively improve the collapsibility of water glass sand.

[0024] (4) The present invention also provides a method for preparing the above-mentioned modified water glass sand. The method involves adding water glass sand modifier and water glass sand silane coupling agent into water glass sand in a specific order and process steps, so that the prepared modified water glass sand has good performance. In addition, the preparation method is simple, green and environmentally friendly, and has industrial application value. Detailed Implementation

[0025] The present invention will now be described in detail with reference to specific implementation methods.

[0026] The composite modified water glass sand binder of the present invention is composed of the following raw materials by weight percentage: 10% to 20% modifier, 60% to 70% water glass, and 10% to 30% silane coupling agent, with the total content of the above components being 100%.

[0027] The modifier is composed of the following raw materials by weight percentage: 35% to 45% titanium dioxide powder, 25% to 40% N-hydroxysuccinimide, and 15% to 40% trihydroxypolyoxypropylene ether, with the total content of the above components being 100%.

[0028] The silane coupling agent is made from the following raw materials by weight percentage: 30%–35% γ-aminopropylmethyldiethoxysilane, 35%–40% cyclohexylaminopropylsilane, and 25%–35% methyltrimethoxysilane, with the total content of the above components being 100%.

[0029] The preparation method of composite modified water glass sand is carried out according to the following steps:

[0030] Step 1: Mix all the raw materials of water glass sand silane coupling agent evenly according to the formula to obtain mixture A;

[0031] In step 1, the time required to fully mix each raw material and mix it with the original sand is 2-3 minutes.

[0032] Step 2: After drying mixture A, mix it evenly with the original sand to obtain mixture B;

[0033] In step 2, the drying time is 5-8 hours and the temperature is 120-150℃.

[0034] Step 3: Mix and heat the raw materials of the water glass sand modifier with water glass according to the formula amount, and after mixing evenly, add it to mixture B and mix evenly to obtain modified water glass sand.

[0035] In step 3, the raw materials of the modifier are stirred and heated according to the formula. After being mixed evenly, they are added to mixture B and mixed evenly for 4-5 minutes to obtain modified water glass sand.

[0036] In this invention, modified water glass sand is obtained by mixing water glass sand with the above-mentioned water glass sand modifier and silane coupling agent in a specific ratio. The use of water glass sand modifier and silane coupling agent can significantly improve the bonding strength of modified water glass sand, greatly reduce the amount of modified glass sand added, and effectively improve the collapsibility of water glass sand.

[0037] By rationally selecting and combining the components of the modifier and silane coupling agent, the components work synergistically, resulting in a reduction in the residual strength of the water glass sand with the addition of the water glass sand modifier and water glass sand silane coupling agent, a significant improvement in the collapsibility of the water glass sand, and an increase in the utilization rate of old sand.

[0038] Example 1

[0039] The composite modified water glass sand binder is composed of the following raw materials by weight percentage: 15% modifier, 65% water glass, and 20% silane coupling agent, with the total content of the above components being 100%.

[0040] The modifier is composed of the following raw materials by weight percentage: 35% titanium dioxide powder, 25% N-hydroxysuccinimide, and 40% trihydroxypolyoxypropylene ether, with the total content of the above components being 100%.

[0041] The silane coupling agent is composed of the following raw materials by weight percentage: 30% γ-aminopropylmethyldiethoxysilane, 35% cyclohexylaminopropylsilane, and 35% methyltrimethoxysilane, with the total content of the above components being 100%.

[0042] The powders of water glass sand modifier titanium dioxide powder, N-hydroxysuccinimide, and trihydroxypolyoxypropylene ether were crushed to 130 mesh, mixed evenly according to the formula, and then wet-milled to obtain mixture A. The solvent used during milling was ethanol, and the weight ratio of modifier to ethanol was 0.8:1. The ball mill speed was set to 160 r / min, and the milling time was 1.5 h.

[0043] After drying mixture A in a forced-air drying oven, it is mixed evenly with water glass sand to obtain mixture B; wherein the drying temperature is 120℃, the drying time is 8h, and the mixing time is 4min.

[0044] The raw materials of water glass sand silane coupling agent γ-aminopropylmethyldiethoxysilane, cyclohexylaminopropylsilane and methyltrimethoxysilane are stirred and heated with water glass according to the formula amount. After being mixed evenly, they are added to mixture B and mixed evenly to obtain the composite modified water glass sand of the present invention.

[0045] Example 2

[0046] The composite modified water glass sand binder is composed of the following raw materials by weight percentage: 10% modifier, 60% water glass, and 30% silane coupling agent, with the total content of the above components being 100%.

[0047] The modifier is composed of the following raw materials by weight percentage: 45% titanium dioxide powder, 40% N-hydroxysuccinimide, and 15% trihydroxypolyoxypropylene ether, with the total content of the above components being 100%.

[0048] The silane coupling agent is composed of the following raw materials by weight percentage: 35% γ-aminopropylmethyldiethoxysilane, 40% cyclohexylaminopropylsilane, and 25% methyltrimethoxysilane, with the total content of the above components being 100%.

[0049] The powders of water glass sand modifier titanium dioxide powder, N-hydroxysuccinimide, and trihydroxypolyoxypropylene ether were crushed to 100 mesh, mixed evenly according to the formula, and then wet-milled to obtain mixture A. The solvent used during milling was ethanol, and the weight ratio of modifier to ethanol was 0.82:1. The speed of the ball mill was set to 150 r / min, and the milling time was 2 h.

[0050] After drying mixture A in a forced-air drying oven, it is mixed evenly with water glass sand to obtain mixture B; wherein, the drying temperature is 115℃, the drying time is 9h, and the mixing time is 3.5min.

[0051] The raw materials of γ-aminopropylmethyldiethoxysilane, cyclohexylaminopropylsilane and methyltrimethoxysilane, which are silane coupling agents for water glass sand, are stirred and heated with water glass according to the formula amount. After being mixed evenly, they are added to mixture B and mixed evenly to obtain the composite modified water glass sand of the present invention.

[0052] Example 3

[0053] The composite modified water glass sand binder is composed of the following raw materials by weight percentage: 20% modifier, 70% water glass, and 10% silane coupling agent, with the total content of the above components being 100%.

[0054] The modifier is composed of the following raw materials by weight percentage: 40% titanium dioxide powder, 35% N-hydroxysuccinimide, and 25% trihydroxypolyoxypropylene ether, with the total content of the above components being 100%.

[0055] The silane coupling agent is composed of the following raw materials by weight percentage: 32% γ-aminopropylmethyldiethoxysilane, 38% cyclohexylaminopropylsilane, and 40% methyltrimethoxysilane, with the total content of the above components being 100%.

[0056] The powders of water glass sand modifier titanium dioxide powder, N-hydroxysuccinimide, and trihydroxypolyoxypropylene ether were crushed to 140 mesh, mixed evenly according to the formula, and then wet-milled to obtain mixture A. The solvent used during milling was ethanol, and the weight ratio of inorganic modifier to ethanol was 0.86:1. The speed of the ball mill was set to 170 r / min, and the milling time was 0.5 h.

[0057] After drying mixture A in a forced-air drying oven, it is mixed evenly with water glass sand to obtain mixture B; wherein, the drying temperature is 126℃, the drying time is 7h, and the mixing time is 4.5min.

[0058] The raw materials of γ-aminopropylmethyldiethoxysilane, cyclohexylaminopropylsilane and methyltrimethoxysilane, which are silane coupling agents for water glass sand, are stirred and heated with water glass according to the formula amount. After being mixed evenly, they are added to mixture B and mixed evenly to obtain the composite modified water glass sand of the present invention.

Claims

1. A composite modified water glass sand binder, characterized by, It is composed of the following raw materials by weight percentage: 10% to 20% modifier, 60% to 70% water glass, 10% to 30% silane coupling agent, and the total content of the above components is 100%. The modifier, by weight percentage, is mainly made of the following raw materials: 35% to 45% titanium dioxide powder, 25% to 40% N-hydroxysuccinimide, and 15% to 40% trihydroxypolyoxypropylene ether, with the total content of the above components being 100%. The silane coupling agent is mainly made from the following raw materials by weight percentage: 30% to 35% γ-aminopropylmethyldiethoxysilane, 35% to 40% cyclohexylaminopropylsilane, and 25% to 35% methyltrimethoxysilane, with the total content of the above components being 100%.

2. A method of preparing a composite modified water glass sand binder as claimed in claim 1, characterized by, The main steps include: Step 1: Mix all the raw materials of water glass sand silane coupling agent evenly according to the formula to obtain mixture A; Step 2: After drying mixture A, mix it evenly with the original sand to obtain mixture B; Step 3: Mix and heat the raw materials of the water glass sand modifier with water glass according to the formula, and after mixing evenly, add it to mixture B and mix evenly to obtain the composite modified water glass sand binder.

3. The preparation method of the composite modified water glass sand binder according to claim 2, characterized in that, The steps are implemented in the following manner: In step 1, the time required to fully mix each raw material and mix it with the original sand is 2-3 minutes. In step 2, the drying time is 5-8 hours and the temperature is 120-150℃; In step 3, the raw materials of the modifier are stirred and heated according to the formula. After being mixed evenly, they are added to mixture B and mixed evenly for 4-5 minutes to obtain the composite modified water glass sand binder.