CN102898113A - Hydrophobic expanded perlite heat insulating product and preparation method thereof - Google Patents

Abstract

The invention relates to a water-repellent expanded perlite thermal insulation product and a preparation method thereof. The material is particularly suitable for the thermal insulation of building exterior walls, and the equipment and pipelines for alternating cold and heat. The product uses potassium methyl silicate and polydimethylsiloxane as composite water-repellent agents, so that the water-repellent rate of the product is not less than 99.7%. The ingredient composition (by weight) of the hydrophobic expanded perlite insulation product: 20%-35% expanded perlite particles, 63%-75% sodium silicate aqueous solution, 1.0%-4.5% potassium methyl silicate And 0.5%-2% polydimethylsiloxane. The product has high hydrophobicity, low apparent density, small thermal conductivity and high mechanical strength, which overcomes the problems of thermal conductivity, mechanical strength and hydrophobicity of traditional perlite products.

Description

Hydrophobic expanded perlite thermal insulation product and preparation method thereof

Technical field:

The invention relates to an expanded perlite thermal insulation product, in particular to a hydrophobic expanded perlite thermal insulation product. The product has excellent hydrophobic effect, light weight and high strength, low thermal conductivity, good mechanical properties, and the combustion grade of the material is Class A. It is suitable for building insulation, pipelines, equipment and other parts that require thermal insulation, especially in humid environments.

Background technique

At present, China is the largest construction market in the world, with an annual increase of approximately 2 billion cubic meters of construction area, of which more than 95% are high-energy buildings. If no effective energy-saving measures are taken, China's construction energy will account for China's total energy consumption by 2020. 50%, which will bring huge energy loss. The Chinese government has successively promulgated building energy conservation policies in the form of laws and documents to vigorously promote building energy conservation. Building energy conservation has become a strategically important area for sustainable energy development in China. Therefore, building energy conservation must develop in harmony with the social economy and the ecological environment. It is necessary to pay attention to the thermal insulation performance, practical value, stability and service life of materials, reliability of process technology, ecological environmental protection and recyclability of building materials. Carry out key research and development.

In recent years, there have been many major fire accidents caused by building external insulation materials in China, causing serious casualties and property losses, such as the fire in the auxiliary building of the new CCTV site in Beijing, and the fire in the teachers' apartment in Jiaozhou Bay, Shanghai. Therefore, the country has higher requirements on the fire performance of building insulation materials, which makes inorganic insulation materials with non-combustibility (combustibility grade A) become a hot spot in research, development and application.

Expanded perlite has the characteristics of low apparent density, low thermal conductivity, good chemical stability, wide temperature range, non-toxic, odorless, fireproof, sound-absorbing, etc. It has become an industrial thermal insulation material decades ago. The product forms mainly include granular, plate, shell and other forms. Although there are also building insulation applications, due to the inherent defects of traditional perlite products, its application in building insulation and energy saving is severely limited and affected. Many problems in the practical application of traditional expanded perlite include: 1) High water absorption. Usually its mass water absorption rate is as high as 300%~400%, which makes the expanded perlite thermal insulation products absorb a large amount of water during construction and application, which greatly reduces the thermal insulation performance of the product, and also causes peeling and cracking of the surface particles of the product. Problem; 2) Intensity is extremely low. Due to the porous structure and brittleness of expanded perlite, during the production of expanded perlite thermal insulation products, the expanded perlite will be broken under the action of external force (such as stirring, extrusion, etc.), thereby reducing the thermal insulation products. performance, which severely limits the application of expanded perlite, and the compressive strength of the product is only 0.1MPa. Therefore, reducing water absorption, improving water repellency, and increasing product strength will be the key to the development of traditional perlite products in the field of building energy-saving applications.

Contents of the invention

The purpose of the present invention is based on the background and current situation of the invention and the application problems of the products, to improve the deficiencies and defects of traditional perlite products, to provide a building energy-saving and thermal insulation material with excellent hydrophobic properties that can be applied in humid environmental conditions, and Hydrophobic expanded perlite insulation product with light weight and high strength and low thermal conductivity.

In order to achieve the above object, the hydrophobic expanded perlite thermal insulation product of the present invention adopts commercially available potassium methyl silicate solution with a solid content of 30%-60% and polydimethylsilane with a solid content of 40%-70%. Hydrophobic agent is mixed with base siloxane to form a composite water-repellent agent, and the gist of the present invention is to achieve a more water-repellent effect through the composite effect of the water-repellent agent, and greatly reduce the water absorption of expanded perlite products. The hydrophobic mechanism of polydimethylsiloxane is: polydimethylsiloxane reacts with heat to form a layer of air-permeable and impermeable film on the surface and inside of perlite. The hydrophobic mechanism of potassium methyl silicate is: Potassium methyl silicate will react with _CO2 in the air to produce a layer of insoluble waterproof resin film several molecules thick on the surface of perlite. That is to say, two kinds of water-repellent agents can be used together, and the water-repellent effect will not interfere with each other, and at the same time, they will work in synergy with each other, and the water-repellent effect will be significantly improved.

When potassium methyl silicate water-repellent is used alone, excessive dosage will cause white residue on the surface of the product and affect the appearance of the product; and when one water-repellent is used alone, its water-repellent rate can reach up to 90%-92%. For building insulation materials, it is still far from enough. Therefore, the present invention adopts the method of mixing two kinds of water-repellent agents, which not only solves the problem of poor water-repellent effect of a single water-repellent agent, but also saves raw materials and reduces costs.

The ingredient composition of hydrophobic expanded perlite insulation products is characterized by (by weight): 20%-35% of expanded perlite, 63%-75% of binder, and 1.5%-6.5% of composite water-repellent agent, of which Potassium methyl silicate and polydimethylsiloxane are 1.0%-4.5% and 0.5%-2%, respectively. The binder is an aqueous solution of sodium silicate with a solid content of 3%-15%; the water repellent is potassium methyl silicate with a solid content of 30%-60% and polydimethylsiloxane with a solid content of 40%-70% alkane; the particle size of expanded perlite is 0.1mm-5mm, and the bulk density is 60-100kg/m ³ .

The optimal composition of ingredients for hydrophobic expanded perlite insulation products, in terms of weight percentage, expanded perlite is 26%-29%; sodium silicate solution is 69%-71%; potassium methyl silicate and polydimethyl Siloxanes are 2.0%-3.5% and 1.3%-1.8%, respectively.

A method for preparing a hydrophobic expanded perlite thermal insulation product, which is characterized in that: firstly, a binder and a water-repellent are mixed to obtain a mixed solution; secondly, the mixed solution is sprayed on the surface of expanded perlite particles, and at the same time, it is sent into hot air for drying , and then use a press to press into products, and finally dry the products.

Further, the expanded perlite granules are tossed using a rotary drum mixer, and a spray atomizer is installed on the central axis of the rotary drum mixer to evenly spray the mixed solution on the surface of the expanded perlite particles.

Further, the temperature of the hot air sent in is 50°C-150°C, and the drying time by sending hot air is 15min-40min.

Further, the press is a double-sided press.

Further, the working parameter of the press is 0.20MPa-0.50MPa, and the pressing time is 5-30 seconds.

Further, the drying temperature is 85°C-200°C.

The invention finally obtains the hydrophobic expanded perlite thermal insulation product. Product density ≤ 200kg/m ³ , thermal conductivity < 0.060W/(M·K), water repellency not less than 99.7%, compressive strength > 0.27MPa, flexural strength > 0.07MPa, tensile strength > 20KPa. Among them, the "GBT 5486-2008 Inorganic Rigid Thermal Insulation Products Test Method" is used to test its strength and apparent density, and the "GBT 10299-1988 Thermal Insulation Material Hydrophobicity Test Method" is used to test its water repellency. Measured by the coefficient tester.

Detailed ways

First, the solution part of the above ingredients is uniformly mixed, and secondly, the straight-through drum mixer is used. The reason why the straight-through drum mixer is used instead of the paddle mixer is because the stirring of the paddle mixer The huge shearing force generated by the blade will break the expanded perlite particles, but the straight-through drum mixer can ensure the integrity of the expanded perlite particles to the greatest extent, and the expanded perlite particles from the straight-through drum mixer One end of the mixer is fed to make the perlite particles tumbling, and a long-rod spray atomizer is installed on the central axis of the rotary drum mixer to spray along the circumferential direction, and the mixed solution is evenly sprayed on the expanded perlite particles. On the surface, send hot air at 50-150°C at the same time, and the drying time is more than 10 minutes. Under the drying effect, the water glass solution (melt glue) initially gels on the surface of the particles, and gradually closes the capillary pores inside the particles, which plays a role Reduce water absorption, and at the same time, due to the preliminary vitrification (gelation) of water glass, the perlite particles have a certain rigidity, which effectively prevents and solves the problem of the traditional perlite particles being easy to pulverize, that is, the particles are under slight action conditions. The situation of turning into fine powder is mainly due to the extremely low strength of traditional perlite particles, which can effectively avoid the damage of perlite particles. Under the same conditions, the breakage rate is only 3-5% of the original. When the particles sprayed with the mixed solution on the surface of the perlite are unscrewed from the other end of the drum mixer, the expanded perlite particles sprayed with the mixed solution are sent into the mold of the double-sided press. The reason why the double-sided press is used instead of The reason for the single-sided press is that when the single-sided press is used for pressing, the expanded perlite particles at the indenter are relatively densely pressed, and the expanded perlite particles on the side away from the indenter are relatively loose and separated from the pressure. The farther the head is, the looser it is, and the use of a double-sided press ensures that the expanded perlite particles are fully compacted and compacted. Using the working condition of 0.20MPa-0.50MPa, press for 5-30 seconds, and then remove the product from the mold. Then send the demolded product into an oven and dry it at 85°C-200°C. Under the action of drying, the moisture in the product is completely discharged, and the binder water glass produces a complete gel effect, which bonds the expanded perlite particles together, so that the product develops strength. The water-repellent agent added at the same time produces a series of chemical reactions under the action of drying, making the product produce water-repellent effect from the inside to the outside.

Example 1

The ingredient composition (by weight) of the hydrophobic expanded perlite product is: expanded perlite is 20%, binder is 75%, and water-repellent agent is 5%. The binder is a sodium silicate aqueous solution with a solid content of 3%. The particle size of expanded perlite is 0.1mm-2mm, accounting for 25%, 2mm-5mm accounting for 75%, the bulk density is 60kg/m ³ , and the water-repellent agent is The commercially available polydimethylsiloxane emulsion with a solid content of 40% accounts for 0.5% of the formulation and the potassium methyl silicate solution with a solid content of 60% accounts for 4.5% of the formulation.

A straight-through rotary drum mixer is used to feed the expanded perlite particles from one end of the mixer to make the perlite particles tumbling, and a long-rod spray atomizer is installed on the central axis of the rotary drum mixer. Spray along the circumferential direction, spray the mixed solution evenly on the surface of the expanded perlite particles, and at the same time send hot air at 100°C to dry the surface moisture of the particles for 15 minutes, and at the same time make the sodium silicate solution form a silica gel film on the perlite particles to promote pearl The rock particles produce a certain rigidity and particle toughness, which can avoid the damage of the particles. The perlite particles sprayed with the mixed solution on the surface come out from the other end of the rotary mixer, and the quantitative volume of the expanded perlite that has been sprayed with the mixed solution is sent to the plate. In the mold of the double-sided press, the working condition of 0.50MPa is used to press for 5 seconds, and then the product is removed from the mold and sent to a drying oven for drying at a drying temperature of 200°C. Finally, a hydrophobic expanded perlite insulation product is formed, with an apparent density of 153.9kg/m ³ , a thermal conductivity of 0.0501W/(m·k), a hydrophobicity of 99.70%, a compressive strength of 0.2014MPa, and a flexural strength of 0.0574MPa, pull-out strength 21KPa.

Example 2

The ingredient composition (by weight) of the hydrophobic expanded perlite product is: expanded perlite is 35%, binder is 63%, and water-repellent agent is 2%. The binder is a sodium silicate aqueous solution with a solid content of 15%. The particle size of expanded perlite is 0.1mm-2mm, accounting for 30%, 2mm-5mm accounting for 70%, the bulk density is 80kg/m ³ , and the water repellent is The commercially available polydimethylsiloxane emulsion with a solid content of 40% accounts for 0.5% of the formulation and the potassium methyl silicate solution with a solid content of 60% accounts for 1.5% of the formulation.

A straight-through rotary drum mixer is used to feed the expanded perlite particles from one end of the mixer to make the perlite particles tumbling, and a long-rod spray atomizer is installed on the central axis of the rotary drum mixer. Spray along the circumferential direction, spray the mixed solution evenly on the surface of the expanded perlite particles, and at the same time send hot air at 50°C to dry the surface moisture of the particles for 40 minutes, and at the same time make the sodium silicate solution form a silica gel film on the perlite particles to promote pearl The rock particles produce a certain rigidity and particle toughness, which can avoid the damage of the particles. The perlite particles sprayed with the mixed solution on the surface come out from the other end of the rotary mixer, and the quantitative volume of the expanded perlite that has been sprayed with the mixed solution is sent to the plate. In the mold of the double-sided press, the action condition of 0.20MPa is used to press for 30 seconds, and then the product is removed from the mold and sent to a drying oven for drying at a drying temperature of 8°C. Finally, a hydrophobic expanded perlite insulation product is formed, with an apparent density of 169.2kg/m ³ , a thermal conductivity of 0.0512W/(m·k), a hydrophobicity of 99.76%, a compressive strength of 0.2518MPa, and a flexural strength of 0.0680MPa, pull-out strength 26.4KPa.

Example 3

The ingredient composition (by weight) of the hydrophobic expanded perlite product is: expanded perlite is 30%, binder is 67%, and water-repellent agent is 3%. The binder is a sodium silicate aqueous solution with a solid content of 10%. The particle size of expanded perlite is 0.1mm-2mm, accounting for 40%, 2mm-5mm accounting for 60%, the bulk density is 90kg/m ³ , and the water repellent is The commercially available polydimethylsiloxane emulsion with a solid content of 60% accounts for 2% of the formulation and the potassium methyl silicate solution with a solid content of 60% accounts for 1.0% of the formulation.

A straight-through rotary drum mixer is used to feed the expanded perlite particles from one end of the mixer to make the perlite particles tumbling, and a long-rod spray atomizer is installed on the central axis of the rotary drum mixer. Spray along the circumferential direction, spray the mixed solution evenly on the surface of the expanded perlite particles, and at the same time send hot air at 70°C to dry the water on the surface of the particles for 30 minutes, and at the same time make the sodium silicate solution form a silica gel film on the perlite particles to promote pearl The rock particles produce a certain rigidity and particle toughness, which can avoid the damage of the particles. The perlite particles sprayed with the mixed solution on the surface come out from the other end of the rotary mixer, and the quantitative volume of the expanded perlite that has been sprayed with the mixed solution is sent to the plate. In the mold of the double-sided press, the action condition of 0.31MPa is used to press for 15 seconds, and then the product is removed from the mold and sent to a drying oven for drying at a drying temperature of 105°C. Finally, a hydrophobic expanded perlite insulation product is formed, with an apparent density of 194.2kg/m ³ , a thermal conductivity of 0.0547W/(m·k), a hydrophobicity of 99.81%, a compressive strength of 0.2843MPa, and a flexural strength of 0.0721MPa, pull-out strength 29.4KPa.

Example 4

The ingredient composition (by weight) of the hydrophobic expanded perlite product is: expanded perlite is 32%, binder is 62.5%, and water-repellent agent is 5.5%. The binder is a sodium silicate aqueous solution with a solid content of 10%. The particle size of expanded perlite is 0.1mm-2mm, accounting for 50%, and 2mm-5mm accounting for 50%. The bulk density is 100kg/m ³ , and the water repellent is The commercially available polydimethylsiloxane emulsion with a solid content of 50% accounts for 1.0% of the formulation and the potassium methyl silicate solution with a solid content of 50% accounts for 4.5% of the formulation.

A straight-through rotary drum mixer is used to feed the expanded perlite particles from one end of the mixer to make the perlite particles tumbling, and a long-rod spray atomizer is installed on the central axis of the rotary drum mixer. Spray along the circumferential direction, spray the mixed solution evenly on the surface of the expanded perlite particles, and at the same time send hot air at 85°C to dry the water on the surface of the particles for 20 minutes, and at the same time make the sodium silicate solution form a silica gel film on the perlite particles to promote pearl The rock particles produce a certain rigidity and particle toughness, which can avoid the damage of the particles. The perlite particles of the mixed solution sprayed on the surface come out from the other end of the rotary drum mixer, and the quantitative volume of expanded perlite that has been sprayed with the mixed solution is sent into the In the flat double-sided press mold, the action condition of 0.42MPa is used to press for 25 seconds, and then the product is removed from the mold and sent to a drying oven for drying at a drying temperature of 150°C. Finally, a hydrophobic expanded perlite insulation product is formed, with an apparent density of 197.6kg/m ³ , a thermal conductivity of 0.0599W/(m·k), a hydrophobicity of 99.83%, a compressive strength of 0.3293MPa, and a flexural strength of 0.0890MPa, pull-out strength 38.1KPa.

Claims (8)

1. moisture proof expansive Pearle heat insulating products, its composition is characterised in that: by weight, pearlstone is 20%-35%, and binding agent is 63%-75%, hydrophober 1.5%-6.5%;

Described hydrophober adopts composite water-repellent, and wherein solid content is the 1.0%-4.5% that the methyl siliconic acid potassium solution of 30%-60% accounts for composition; Solid content is the 0.5%-2.0% that the polydimethylsiloxane of 40%-70% accounts for batching; It is the sodium silicate aqueous solution of 3%-15% that described binding agent adopts solid content.

2. described a kind of moisture proof expansive Pearle heat insulating products according to claim 1, it is characterized in that: described expanded perlite granule particle diameter is 0.1mm-5mm, tap density is 60 ~ 100kg/m ³

3. the preparation method of described a kind of moisture proof expansive Pearle heat insulating products according to claim 1, it is characterized in that: at first binding agent and hydrophober are mixed to get mixing solutions, secondly mixing solutions is sprayed on the expanded perlite granule surface, send into simultaneously warm air drying, adopt again press to be pressed into goods, at last goods are dried.

4. described method according to claim 3, it is characterized in that: utilize the cylinder-rotating mixer, expanded perlite granule is seethed, in cylinder-rotating mixer central axis position the spray atomization device is set, mixing solutions evenly is sprayed on the expanded perlite granule surface.

5. described method according to claim 3, it is characterized in that: the described hot blast temperature of sending into is 50 ℃-150 ℃, and the time of sending warm air drying is 15min-40min.

6. described method according to claim 3, it is characterized in that: described press is two-sided pressing machine.

7. described method according to claim 3 is characterized in that the press working parameter is 0.20MPa-0.50MPa, and the press time is 5-30 second.

8. described method according to claim 3, it is characterized in that: described bake out temperature is 85 ℃-200 ℃.