Silica aerogel master batch as well as preparation method and application thereof

Abstract

The invention relates to the field of composite material processing, and discloses a silica aerogel master batch as well as a preparation method and application thereof. The preparation method comprises the following steps: in the presence of water, contacting polyvinyl alcohol with hydrophobic silicon dioxide aerogel, and stirring at a high speed to obtain a mixture; the viscosity of the mixture at the temperature of 20 DEG C ranges from 50000 mPa.s to 100000 mPa.s; the weight-average molecular weight of the polyvinyl alcohol is 20000 to 200000 g / mol; the alcoholysis degree is greater than 78%; and mixing the obtained mixture with glass beads. The preparation method provided by the invention has the advantages that the preparation efficiency is high, the preparation process is pollution-free, the silicon dioxide aerogel structure is not damaged, the obtained silica aerogel master batch has better lightweight effect, hydrophobic effect, heat insulation effect and compounding effect, and the silica aerogel master batch can be randomly formed before being dried, so that the service life of the silica aerogel master batch is prolonged. And plasticity reduction can be realized through contact heating with hot water of which the temperature is greater than or equal to 90 DEG C.

Description

Technical Field

[0001] The invention relates to the field of composite material processing, and in particular to a silicon aerogel masterbatch and a preparation method and application thereof. Background Art

[0002] With the development of science and technology and the improvement of people's living standards, people have begun to pursue a green and healthy living environment, and have more stringent requirements for reducing carbon emissions and energy consumption. Lightweight design refers to the act of reducing the amount of material in a component to reduce its overall weight without sacrificing reliability or functionality. On the one hand, it can reduce carbon emissions and energy consumption, and on the other hand, it can achieve better component performance. Lightweight design aims to provide manufacturers with the solutions they need to meet the challenges of climate change, while achieving better component performance and extending product life.

[0003] Aerogel is the world's smallest solid. 2 Aerogel is the lowest cost and most commercialized product among aerogel products, and it is also the lightest solid material and the best thermal insulation material known so far. It has nanometer-level pore size, which can largely avoid heat transfer from air. Its extremely low volume density and the tortuous path of the nano-grid structure also prevent gaseous and solid heat conduction, making aerogel achieve an insulation effect that other materials cannot match; and because of its extremely low density, it can also achieve the purpose of lightweight to a great extent after being compounded with other materials.

[0004] Glass microspheres are a new type of material developed in recent years. They are hollow spheres made of borosilicate and have a micron-level hollowness, which gives them extremely low density. And because the air inside them has difficulty in heat transfer and poor thermal conductivity, they have a certain thermal insulation ability. The chemical properties of the surface of glass microspheres are stable and they are very easy to disperse in organic material systems. They are an excellent lightweight filler. They are used as lightweight fillers in industry.

[0005] Therefore, using SiO 2 Aerogel preparation and composite processing of aerogel masterbatch can make the material meet the requirements of lightweight.

[0006] At present, about SiO 2 The use of aerogel is mostly concentrated on the coating method, which applies silicon aerogel to the surface of the material to achieve the effect of thermal insulation. Although it is easy to mass produce, it has poor feel and durability and cannot meet the requirements of lightweight.

[0007] In SiO 2 In terms of aerogel composite, SiO 2Aerogel has low density and is easy to float. It has serious dust problem during the composite processing with plastic, which has great harm to the durability of equipment and the health of workers. Due to its low density, it is easy to accumulate and float at the feeding port of the twin screw, making it difficult to feed and composite with plastic in the twin screw, and the composite effect is poor. And through general screw processing, it is easy to make SiO 2 The aerogel breaks under the shear force of the screw and cannot maintain its pore structure, making the SiO 2 Aerogel loses its original properties and cannot achieve lightweight and heat insulation effects. Traditional silica aerogel is fragile when used, so it is usually processed into aerogel powder for use, which has a single use condition and is not universal.

[0008] CN114196181A discloses a polylactic acid and silica aerogel composite masterbatch and a preparation method thereof, wherein the masterbatch comprises the following components by weight: 75-90 parts of polylactic acid, 10-25 parts of silica aerogel powder, 160.1-0.25 parts of polysiloxane quaternary ammonium salt, and 0.1-0.25 parts of polar amide wax. Although the thermal conductivity of the filament fiber obtained by mixing the masterbatch with PLA is lower than that of pure wool, and it has excellent thermal insulation and biodegradability, its lightweight effect still needs to be improved.

[0009] CN113563049A discloses a high thermal stability, low calorific value hydrophobic silica aerogel composite material and its preparation method, which uses an inorganic silicon source as a precursor, undergoes gelation and modification to obtain a hydrophobic gel; then the base material is impregnated in the hydrophobic gel to obtain a pre-treated composite material; when the organic silicon source is used as a precursor, the base material is added during the gelation process so that the base material fully absorbs the silicon source hydrolyzate; then the gel composite system is sequentially replaced by alcohol and alkane to obtain a pre-treated composite material; then the pre-treated composite material is heat-treated to orderly reduce the number of methyl groups on the surface of the silica aerogel, and reduce the residual organic liquid on its surface and in the pores, and optimize its microscopic morphology. The preparation process of this method is complicated and the preparation efficiency is low.

[0010] CN111041587A discloses a silicon dioxide aerogel modified polypropylene melt-blown nonwoven material and a preparation method thereof, wherein tetraethyl orthosilicate is used as a silicon source and SiO is prepared by a sol-gel method. 2 Aerogel, SiO 2 The aerogel was hydrophobically modified and crushed to obtain hydrophobic SiO 2 Aerogel powder and polypropylene chips were mixed and melted to form SiO 2 Aerogel / polypropylene composite masterbatch was mixed with pure polypropylene and melt-blown to produce SiO 2Aerogel-modified polypropylene melt-blown nonwoven material. This method requires the use of twin-screw processing equipment, which is complicated to operate and has aerogel dust problems and health hazards.

[0011] CN113277832A discloses a method for preparing a PVDF / silica aerogel membrane material, which comprises preparing a spinning precursor solution with PVDF, an organic solvent and a silica aerogel, and preparing a PVDF fiber / silica aerogel non-woven membrane material by using an electrostatic spinning technique through two sets of needles, and then forming a PVDF / silica aerogel membrane material by heat pressing. This method requires the use of an organic solvent, which is not conducive to the health of the operator. Summary of the invention

[0012] The purpose of the present invention is to overcome the problems of lightweight, poor composite effect and aerogel dust in the existing silicon aerogel preparation and composite process.

[0013] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a silica aerogel masterbatch, the preparation method comprising:

[0014] (1) in the presence of water, polyvinyl alcohol is contacted with silica aerogel and stirred at high speed to obtain a mixture; wherein the viscosity of the mixture at 20° C. is 50,000-100,000 mPa·s; the weight average molecular weight of the polyvinyl alcohol is 20,000-200,000 g / mol; the alcoholysis degree of the polyvinyl alcohol is greater than 78%; and the silica aerogel is a hydrophobic silica aerogel;

[0015] (2) Mixing the mixture with glass microspheres.

[0016] The second aspect of the present invention provides a silica aerogel masterbatch prepared by the preparation method described in the first aspect.

[0017] The third aspect of the present invention provides use of the silicone aerogel masterbatch as described in the second aspect in thermal insulation fillers and / or resin additives.

[0018] Through the above technical scheme, the preparation method of silicon aerogel masterbatch provided by the present invention is aimed at the traditional SiO 2 The various drawbacks in the use and processing of aerogels are solved by contacting a specific polyvinyl alcohol with a hydrophobic silica aerogel in the presence of water and stirring at a high speed to obtain a mixture with a specific viscosity, and then mixing the mixture with glass microbeads to prepare a silica aerogel masterbatch.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. In the preparation method provided by the present invention, polyvinyl alcohol is contacted with hydrophobic silica aerogel in the presence of water and stirred at a high speed. No toxic or harmful organic solvent is used in the above process, which is more environmentally friendly and will not harm human health. In addition, since an aqueous system is used and the silica aerogel powder is hydrophobic, water will not enter its structure. The entire preparation process mainly realizes physical coating, thereby maintaining the integrity of the aerogel structure.

[0021] 2. The mixed masterbatch has plasticity due to the presence of water, and can be arbitrarily formed according to the needs, without being restricted by the use mode and the use environment; and by drying the masterbatch to volatilize the water, the obtained silicon aerogel masterbatch is transformed into a brittle and hard state, which cannot be deformed, and because the silicon aerogel masterbatch is hydrophobic, it is difficult to absorb water at a temperature below 90°C; at the same time, by heating the silicon aerogel masterbatch in contact with hot water at a temperature ≥ 90°C, the silicon aerogel masterbatch can absorb water and be transformed into the plastic masterbatch again;

[0022] 3. The preparation method provided by the present invention is to prepare 2 The preparation of silicon aerogel masterbatch from aerogel finished products greatly saves preparation time and improves preparation efficiency; the preparation process does not require the use of processing equipment such as twin screws, which is simple to operate, safer and more energy-saving, and there is no aerogel flying; in addition, the SiO contained in the silicon aerogel masterbatch 2 Aerogel occupies the main position, which is more in line with the direction of aerogel masterbatch preparation and customer needs;

[0023] 4. The silica aerogel masterbatch provided by the present invention has a low density and a better lightweight effect, which is conducive to avoiding the problem of dust flying during the compounding process with engineering plastics such as nylon 6, and the preparation process and the subsequent use process are pollution-free;

[0024] 5. The silica aerogel masterbatch provided by the present invention has hydrophobicity and flame retardancy, which reduces its transportation and storage standards; and its thermal insulation effect is good, compared with the traditional use of SiO 2 The method of applying aerogel to the surface of a material for heat insulation, the silicon aerogel masterbatch prepared by the present invention is compounded with plastic for heat insulation, the obtained heat insulation material has a longer service life, the product feels better, and the product appearance is smoother and more natural, which plays a beautifying role. In addition, the silicon aerogel masterbatch has a certain antioxidant effect, which can improve the oxidation yellowing phenomenon of engineering plastics such as nylon 6, and realize a wider application.

[0025] In summary, the preparation method provided by the present invention has high preparation efficiency, no pollution in the preparation process, and does not damage SiO 2Aerogel structure, the obtained silicone aerogel masterbatch has better lightweight effect, hydrophobic effect, heat insulation effect and composite effect, and it can be arbitrarily formed before drying, and can also be heated by contact with hot water at a temperature of ≥90°C to achieve plasticity restoration. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is an appearance diagram of a product obtained by contacting polyvinyl alcohol with hydrophobic silica aerogel (before high-speed stirring) in a preparation method according to a specific embodiment of the present invention;

[0027] Figure 2 This is an appearance diagram of a masterbatch obtained by a preparation method according to a specific embodiment of the present invention;

[0028] Figure 3 This is an appearance diagram of a masterbatch obtained by a preparation method according to a specific embodiment of the present invention;

[0029] Figure 4 This is a test diagram of the hydrophobic angle of the silica aerogel masterbatch prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0031] As mentioned above, the first aspect of the present invention provides a method for preparing a silica aerogel masterbatch, the preparation method comprising:

[0032] (1) in the presence of water, polyvinyl alcohol is contacted with silica aerogel and stirred at high speed to obtain a mixture; wherein the viscosity of the mixture at 20° C. is 50,000-100,000 mPa·s; the weight average molecular weight of the polyvinyl alcohol is 20,000-200,000 g / mol; the alcoholysis degree of the polyvinyl alcohol is greater than 78%; and the silica aerogel is a hydrophobic silica aerogel;

[0033] (2) Mixing the mixture with glass microspheres.

[0034] Polyvinyl alcohol (PVA) is an amphiphilic macromolecule obtained by alcoholysis of polyvinyl acetate. It has a simple molecular structure and consists of hydrophobic (-CH 2 -CH 2-) main chain and hydrophilic (-OH) side groups. It is an organic compound, a water-soluble polymer, and has low cost, biodegradability, non-toxicity and environmental protection, which meets the needs of green development.

[0035] The inventors of the present invention found in the course of their research that a mixture with a specific viscosity is obtained by contacting a specific polyvinyl alcohol with a hydrophobic silica aerogel in the presence of water and stirring at a high speed, and then the mixture is mixed with glass microbeads to prepare a silica aerogel masterbatch. In the above process, no toxic or harmful organic solvents are needed, and since a water-based system is used, SiO 2 Aerogel powder is hydrophobic, water will not enter its structure, and the entire preparation process mainly achieves physical coating, thereby maintaining the integrity of the aerogel structure. The preparation method has high preparation efficiency, no pollution in the preparation process, and does not damage SiO 2 Aerogel structure, the obtained silicone aerogel masterbatch has better lightweight effect, thermal insulation effect and composite effect, and it can be arbitrarily formed before drying, and can also be heated by contact with hot water at a temperature ≥90°C to achieve plasticity restoration.

[0036] According to some embodiments of the present invention, in step (1), polyvinyl alcohol is contacted with hydrophobic silica aerogel in the presence of water and stirred at high speed to obtain a mixture; wherein the viscosity of the mixture at 20°C is 50,000-100,000 mPa·s. In the above process, in the product obtained by contacting polyvinyl alcohol with hydrophobic silica aerogel (before stirring at high speed), the silica aerogel floats on the upper layer of the PVA aqueous solution due to its low density, such as Figure 1 As shown. During the high-speed stirring process, the two are gradually mixed, and the height of the silica aerogel floating layer gradually decreases, and finally a mixture that meets the above-mentioned specific viscosity requirements is formed, which is similar to a creamy liquid with poor fluidity. By forming a mixture that meets the above-mentioned specific viscosity requirements, it is beneficial to shape the masterbatch.

[0037] According to some embodiments of the present invention, preferably, in step (1), the viscosity of the mixture at 20° C. is 70,000-80,000 mPa·s.

[0038] According to some embodiments of the present invention, preferably, in step (1), the weight average molecular weight of the polyvinyl alcohol is 50,000-150,000 g / mol; and / or the alcoholysis degree of the polyvinyl alcohol is 80-99%.

[0039] The viscosity of the mixture and the specific polyvinyl alcohol of the preferred embodiment are more conducive to the preparation of the moldable masterbatch, and the prepared silicon aerogel masterbatch has a lower density, better thermal insulation and hydrophobic properties. In addition, it is also conducive to promoting the melt processing of silicon aerogel masterbatch and nylon, and the composite effect is better.

[0040] According to some embodiments of the present invention, preferably, in step (1), the high-speed stirring conditions include: a stirring speed of 500-1500 rpm, a stirring temperature of 10-95° C., and a stirring time of 10-30 min. The use of the above preferred embodiment is conducive to further promoting the formation of a mixture that meets the above specific viscosity requirements.

[0041] According to some embodiments of the present invention, preferably, in step (1), the weight ratio of the polyvinyl alcohol to the silica aerogel is 1: 1.8-4. The above preferred embodiment is conducive to further promoting the preparation of the plastic masterbatch, further reducing the density of the silica aerogel masterbatch, and further improving the thermal insulation and hydrophobic properties of the silica aerogel masterbatch.

[0042] According to some embodiments of the present invention, preferably, in step (1), the polyvinyl alcohol is provided in the form of a polyvinyl alcohol aqueous solution. It should be noted that when the polyvinyl alcohol is provided in the form of a polyvinyl alcohol aqueous solution, in step (1), the water in the presence of water is the water in the polyvinyl alcohol aqueous solution.

[0043] According to some embodiments of the present invention, preferably, in step (1), the mass concentration of the polyvinyl alcohol in the water is 5-10%.

[0044] According to some embodiments of the present invention, preferably, in step (1), the particle size D90 of the silica aerogel is ≤30 μm, preferably 8-30 μm.

[0045] According to some embodiments of the present invention, preferably, in step (1), the thermal conductivity of the silica aerogel is 0.0016-0.020 W / (m·K).

[0046] According to some embodiments of the present invention, preferably, in step (1), the tap density of the silica aerogel is 0.04-0.07 g / cm 3 .

[0047] The use of silica aerogel that meets the above-mentioned specific performance parameter requirements is conducive to further promoting the preparation of plastic masterbatch, further reducing the density of silica aerogel masterbatch, and further improving the thermal insulation and hydrophobic properties of silica aerogel masterbatch.

[0048] According to some embodiments of the present invention, in step (2), the mixture is mixed with glass beads. Under the mixing in the above process, the viscosity of the reaction system increases rapidly, and the masterbatch finally obtained has plasticity and is in the form of dough, which can be arbitrarily formed and can be changed according to actual needs, such as block, strip, etc. Figure 2 , Figure 3 shown.

[0049] According to some embodiments of the present invention, preferably, in step (2), the particle size D90 of the glass microbeads is 8-30 μm.

[0050] According to some embodiments of the present invention, preferably, in step (2), the true density of the glass microspheres is 0.3-0.6 g / cm 3 The use of the above preferred embodiment is conducive to further reducing the density of the silica aerogel masterbatch.

[0051] According to some embodiments of the present invention, preferably, in step (2), the compressive strength of the glass microspheres is 6000-28000 MPa.

[0052] The use of glass microspheres that meet the above-mentioned specific performance parameter requirements is conducive to further promoting the preparation of plastic masterbatch, and the obtained silicon aerogel masterbatch has a lower density, better thermal insulation and hydrophobic properties. In addition, it is also conducive to promoting the melt processing of silicon aerogel masterbatch and nylon, and the composite effect is better.

[0053] According to some embodiments of the present invention, preferably, the weight ratio of the polyvinyl alcohol to the glass microspheres is 1:0.15-0.25. The above preferred embodiment is conducive to further promoting the preparation of the plastic masterbatch, and the obtained silicon aerogel masterbatch has a lower density, better thermal insulation and hydrophobic properties. In addition, it is also conducive to promoting the melt processing of silicon aerogel masterbatch and nylon, and the composite effect is better.

[0054] According to some embodiments of the present invention, preferably, in step (2), the mixing conditions include: a mixing speed of 1000-1500 rpm, a mixing temperature of 10-95° C., and a mixing time of no more than 5 min, preferably 2-5 min.

[0055] According to some embodiments of the present invention, preferably, the preparation method further comprises drying the masterbatch obtained by mixing in step (2) to remove moisture in the masterbatch to obtain a silicon aerogel masterbatch, wherein the silicon aerogel masterbatch is in a brittle and hard state, cannot be deformed, is hydrophobic, and is difficult to absorb water at a temperature below 90°C.

[0056] According to some embodiments of the present invention, preferably, the drying conditions include: a drying temperature of 60-80° C. and a drying time of 12-24 hours.

[0057] According to some embodiments of the present invention, preferably, the preparation method further comprises: contacting the dried product (i.e., the silicon aerogel masterbatch) with hot water, preferably boiling water, at a temperature of ≥90°C for heating, so that the dried product absorbs water and is converted into the masterbatch. The plasticity of the masterbatch is conducive to the thermal insulation application of the silicon aerogel masterbatch in more complex environments.

[0058] In the present invention, the boiling water refers to hot water with a temperature of 100°C.

[0059] According to some embodiments of the present invention, preferably, the heating time is 0.5-2 hours.

[0060] As mentioned above, the second aspect of the present invention provides a silica aerogel masterbatch prepared by the preparation method described in the first aspect.

[0061] According to some embodiments of the present invention, preferably, the density of the silica aerogel masterbatch is 0.15-0.25 g / cm 3 The silicon aerogel masterbatch has a low density and has a better lightweight effect.

[0062] According to some embodiments of the present invention, preferably, the hydrophobic angle of the silica aerogel masterbatch is greater than 120°.

[0063] According to some embodiments of the present invention, the silicone aerogel masterbatch has better lightweight, heat insulating and composite effects, and can be arbitrarily shaped before drying, and can also be heated by contact with hot water at a temperature ≥ 90°C to achieve plasticity restoration.

[0064] As mentioned above, the third aspect of the present invention provides the use of the silicone aerogel masterbatch as described in the second aspect in thermal insulation fillers and / or resin additives.

[0065] According to some embodiments of the present invention, the silica aerogel masterbatch can be crushed and used as a thermal insulation filler in the papermaking method to prepare glass fiber wet felt, ceramic fiber paper and other composite materials, and further processed into battery insulation pads (sheets).

[0066] According to some embodiments of the present invention, the silicone aerogel masterbatch can be crushed and used as a thermal insulation filler in a water-based thermal insulation coating. Since the PVA contained in the silicone aerogel masterbatch contains hydroxyl groups on its surface, directly adding the silicone aerogel masterbatch to the water-based coating can solve the problem of uneven dispersion of existing aerogel powder in the water-based coating, and prepare a water-based thermal insulation coating with uniform aerogel dispersion.

[0067] According to some embodiments of the present invention, the silicon aerogel masterbatch can be used as a resin additive to compound with engineering plastics such as nylon 6, thereby achieving lightweighting of the engineering plastics and reducing thermal conductivity. At the same time, the silicon aerogel masterbatch can play an antioxidant role in the melt processing of nylon 6, improve the oxidation yellowing phenomenon caused by the moisture contained in nylon 6, improve the processing conditions of nylon 6, and further expand its application.

[0068] The present invention will be described in detail below through examples.

[0069] In the following examples and comparative examples, unless otherwise specified, the raw materials used are all commercially available products.

[0070] in:

[0071] Polyvinyl alcohol particles were purchased from Kuraray Co., Ltd., Japan, and their brand / model number is 1799;

[0072] Silica aerogel was purchased from AIBAIHE New Materials Co., Ltd.;

[0073] Glass microspheres were purchased from 3M Company of the United States, and their brand / model number is 3M IM16K;

[0074] In the following examples and comparative examples, the relevant characteristic parameters were measured by the following methods:

[0075] The viscosity of the mixture was measured by a viscometer;

[0076] The particle size D90 was measured by a laser particle size analyzer model 3005 purchased from Jinan Micro-Nano Company;

[0077] Thermal conductivity was measured by Hot Disk TPS2500S;

[0078] The tap density is measured by a standard vibrating screen machine;

[0079] The compressive strength was measured by a universal testing machine;

[0080] Density is measured by a densitometer;

[0081] The hydrophobic angle was measured by a contact angle meter.

[0082] Example 1

[0083] (1) in the presence of water, polyvinyl alcohol is contacted with silica aerogel and stirred at high speed to obtain a mixture; wherein the viscosity of the mixture at 20° C. is 80000 mPa·s;

[0084] The conditions for high-speed stirring were: stirring speed of 600 rpm, stirring temperature of 20 °C, and stirring time of 20 min;

[0085] The weight average molecular weight of the polyvinyl alcohol is 74800 g / mol; the alcoholysis degree is 99%; the polyvinyl alcohol is provided in the form of a polyvinyl alcohol aqueous solution, the mass concentration of the polyvinyl alcohol aqueous solution is 10%, and the preparation method thereof is: dissolving polyvinyl alcohol particles in water, and stirring at 95° C. for 6 hours to obtain the polyvinyl alcohol aqueous solution;

[0086] The weight ratio of polyvinyl alcohol to silica aerogel is 1:1.8;

[0087] The silica aerogel is a hydrophobic silica aerogel with a particle size D90 of 30 μm, a thermal conductivity of 0.0016 W / (m·K), and a tap density of 0.05 g / cm 3 ;

[0088] (2) mixing the mixture with glass microspheres; wherein:

[0089] The particle size D90 of the glass microspheres is 30 μm; the true density is 0.46 g / cm 3 ; The compressive strength is 6000MPa; The weight ratio of polyvinyl alcohol to glass microspheres is 1:0.2;

[0090] The mixing conditions were as follows: mixing speed was 1500 rpm, mixing temperature was 25°C, and mixing time was 5 min;

[0091] (3) The mixed masterbatch is extruded through a die and then dried under the following conditions: drying temperature is 60° C. and drying time is 24 hours to obtain a silica aerogel masterbatch.

[0092] Example 2

[0093] (1) in the presence of water, polyvinyl alcohol is contacted with silica aerogel and stirred at high speed to obtain a mixture; wherein the viscosity of the mixture at 20° C. is 70000 mPa·s;

[0094] The conditions for high-speed stirring were: stirring speed of 1500 rpm, stirring temperature of 20 °C, and stirring time of 30 min;

[0095] The weight average molecular weight of the polyvinyl alcohol is 74800 g / mol; the alcoholysis degree is 88%; the polyvinyl alcohol is provided in the form of a polyvinyl alcohol aqueous solution, the mass concentration of the polyvinyl alcohol aqueous solution is 10%, and the preparation method thereof is: dissolving polyvinyl alcohol particles in water, and stirring at 95° C. for 6 hours to obtain the polyvinyl alcohol aqueous solution;

[0096] The weight ratio of polyvinyl alcohol to silica aerogel is 1:1.8;

[0097] The silica aerogel is a hydrophobic silica aerogel with a particle size D90 of 30 μm, a thermal conductivity of 0.0016 W / (m·K), and a tap density of 0.05 g / cm 3 ;

[0098] (2) mixing the mixture with glass microspheres; wherein:

[0099] The particle size D90 of the glass microspheres is 20 μm; the true density is 0.3 g / cm 3 ; The compressive strength is 15000MPa; The weight ratio of polyvinyl alcohol to glass microspheres is 1:0.2;

[0100] The mixing conditions were as follows: mixing speed was 1500 rpm, mixing temperature was 25°C, and mixing time was 5 min;

[0101] (3) The mixed masterbatch is extruded through a die and then dried under the following conditions: drying temperature is 60° C. and drying time is 24 hours to obtain a silica aerogel masterbatch.

[0102] Example 3

[0103] The method of Example 1 is followed, except that in step (1), the weight ratio of polyvinyl alcohol to silica aerogel is 1:1.5; the rest is the same, to obtain silica aerogel masterbatch.

[0104] Example 4

[0105] The method of Example 1 is followed, except that the weight ratio of polyvinyl alcohol to glass microspheres is 1:0.1; the rest is the same, to obtain a silica aerogel masterbatch.

[0106] Comparative Example 1

[0107] The method of Example 1 is followed, except that in step (1), polyvinyl alcohol is replaced by polyvinyl alcohol of model / brand PVA L-8 purchased from Kuraray Co., Ltd. of Japan, with a weight average molecular weight of 30,000 g / mol; the degree of alcoholysis is 72.5%; and the rest are the same to obtain a silica aerogel masterbatch.

[0108] Comparative Example 2

[0109] The method of Example 1 is followed, except that in step (1), the hydrophobic silica aerogel is replaced by a hydrophilic silica aerogel purchased from AIBAIHE Technology Co., Ltd., having a particle size D90 of 30 μm, a thermal conductivity of 0.0016 W / (m·K), and a tap density of 0.05 g / cm 3 ;

[0110] The rest are the same, and the silica aerogel masterbatch is obtained.

[0111] Test Case

[0112] The performance tests of the silica aerogel masterbatch prepared in the embodiment and the comparative example were respectively carried out, including: density, hydrophobic angle, thermal insulation performance, flame retardant performance and antioxidant performance, and the results are shown in Table 1. Among them:

[0113] The thermal insulation performance test is as follows: the prepared silica aerogel masterbatch (thickness 1 cm) is placed on a hot table at 100°C for 2 hours, and its surface temperature is observed using infrared thermal imaging;

[0114] The flame retardant performance test is as follows: the prepared silica aerogel masterbatch is ignited for 30 seconds, and its flame retardant performance is observed after burning for 30 seconds. S Whether it is self-extinguishing;

[0115] The specific test of the antioxidant performance is as follows: the prepared silica aerogel masterbatch and nylon 6 (water content of 0.03wt%) are mixed at a weight ratio of 0.06:1, and processed and extruded in a micro twin-screw, and then the color of the composite material is observed and its density is tested; wherein, the nylon 6 (i.e., without adding silica aerogel masterbatch) is directly processed and extruded in a micro twin-screw, and the color of the obtained material is yellow; the density of the nylon 6 is 1.12g / cm 3 .

[0116] The present invention exemplarily provides a hydrophobic angle test diagram of the silicon aerogel masterbatch prepared in Example 1, as shown in FIG. Figure 4 The test results are shown in Table 1.

[0117] Table 1

[0118]

[0119] It can be seen from the above results that the silica aerogel masterbatch provided by the present invention has better lightweight effect, hydrophobic effect, heat insulation effect and composite effect, and can be arbitrarily shaped before drying, and can also be heated by contact with hot water at a temperature of ≥90°C to achieve plasticity restoration.

[0120] The surface temperature of the silica aerogel masterbatch prepared in Examples 1-4 did not exceed 46°C after being placed on a hot plate at 100°C for 2 hours, indicating that the silica aerogel masterbatch prepared by the preparation method provided by the present invention has a good heat insulation effect;

[0121] Moreover, the silica aerogel masterbatch prepared in Example 1-4 extinguished itself after 30 seconds of burning, and a carbon layer was formed on the surface to protect the interior, indicating that it has good flame retardant properties.

[0122] Furthermore, after the silica aerogel masterbatch prepared in Examples 1-4 was compounded with nylon 6 containing water, the color of the obtained composite material could be changed to white, indicating that the silica aerogel masterbatch prepared by the preparation method provided by the present invention has a certain antioxidant effect on nylon 6;

[0123] In addition, nylon 6 with added silica aerogel masterbatch can be smoothly extruded and granulated under normal processing conditions, and its density is also reduced. After the silica aerogel masterbatch of Example 1 is compounded with nylon 6 at a weight ratio of 0.06:1, the density of the obtained composite material is increased from 1.12 g / cm 3 Down to 1.07g / cm 3 , which decreased by 4.5%, indicating that the use of the silica aerogel masterbatch provided by the present invention can achieve lightweight engineering plastics such as nylon 6, and has a good composite effect;

[0124] Comparing Example 1 with Example 3, it can be seen that the weight ratio of polyvinyl alcohol to silica aerogel is within the preferred range of the present invention, and the prepared silica aerogel masterbatch has a smaller density, better thermal insulation and hydrophobicity;

[0125] Comparing Example 1 and Example 4, it can be seen that the weight ratio of polyvinyl alcohol to glass microspheres is within the preferred range of the present invention, which is conducive to improving the cross-linking degree of PVA, and the obtained silicon aerogel masterbatch has a smaller density, better thermal insulation and hydrophobicity. In addition, it is also conducive to promoting the melt processing of silicon aerogel masterbatch and nylon, and the composite effect is better;

[0126] Comparison of Example 1 and Comparative Example 1 shows that the use of polyvinyl alcohol that meets the specific parameter requirements of the present invention can improve the thermal insulation and hydrophobic properties of the silicon aerogel masterbatch, and can promote the melt processing of the silicon aerogel masterbatch and nylon, so that the obtained composite material has a better lightweight effect and composite effect. In addition, if the alcoholysis degree of polyvinyl alcohol is too low, the degree of crosslinking between it and the glass microspheres is low, which is not conducive to the melt processing of the silicon aerogel masterbatch and nylon;

[0127] By comparing Example 1 and Comparative Example 2, it can be seen that the hydrophobicity of the silica aerogel enables it to maintain its own pore structure when it comes into contact with polyvinyl alcohol in the presence of water, thereby reducing the density of the obtained silica aerogel masterbatch, making it have a better lightweight effect and better thermal insulation and hydrophobic properties.

[0128] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a silicon aerogel masterbatch, It is characterized in that The preparation method comprises: (1) in the presence of water, polyvinyl alcohol is contacted with silica aerogel and stirred at high speed to obtain a mixture; wherein the viscosity of the mixture at 20° C. is 50,000-100,000 mPa·s; the weight average molecular weight of the polyvinyl alcohol is 20,000-200,000 g / mol; the alcoholysis degree of the polyvinyl alcohol is greater than 78%; and the silica aerogel is a hydrophobic silica aerogel; (2) Mixing the mixture with glass microspheres.

2. The preparation method according to claim 1, in, In step (1), the high-speed stirring conditions include: a stirring speed of 500-1500 rpm, a stirring temperature of 10-95° C., and a stirring time of 10-30 min.

3. The preparation method according to claim 1, in, In step (1), the weight ratio of the polyvinyl alcohol to the silica aerogel is 1:1.8-4; And / or, the mass concentration of the polyvinyl alcohol in the water is 5-10%; Preferably, the viscosity of the mixture at 20° C. is 70000-80000 mPa·s; Preferably, the weight average molecular weight of the polyvinyl alcohol is 50,000-150,000 g / mol; and / or the alcoholysis degree of the polyvinyl alcohol is 80-99%.

4. The preparation method according to any one of claims 1 to 3, in, In step (1), the particle size D90 of the silica aerogel is ≤30 μm, preferably 8-30 μm; Preferably, the thermal conductivity of the silica aerogel is 0.0016-0.020 W / (m·K); Preferably, the tap density of the silica aerogel is 0.04-0.07 g / cm 3 .

5. The preparation method according to any one of claims 1 to 3, in, In step (2), the particle size D90 of the glass microbeads is 8-30 μm; And / or, the actual density of the glass microspheres is 0.3-0.6 g / cm 3 ; And / or, the compressive strength of the glass microspheres is 6000-28000 MPa.

6. The preparation method according to any one of claims 1 to 3, in, The weight ratio of the polyvinyl alcohol to the glass microspheres is 1:0.15-0.

25.

7. The preparation method according to any one of claims 1 to 3, in, In step (2), the mixing conditions include: mixing speed of 1000-1500 rpm, mixing temperature of 10-95° C., and mixing time of no more than 5 min, preferably 2-5 min.

8. The preparation method according to any one of claims 1 to 3, in, The preparation method further comprises drying the masterbatch obtained by mixing in step (2); Preferably, the drying conditions include: drying temperature of 60-80°C, drying time of 12-24 hours; Preferably, the preparation method further comprises: contacting the dried product with hot water, preferably boiling water, having a temperature of ≥90° C. for heating, so that the dried product absorbs water and is converted into the masterbatch; Preferably, the heating time is 0.5-2 hours.

9. A silicon aerogel masterbatch prepared by the preparation method according to any one of claims 1 to 8; Preferably, the density of the silica aerogel masterbatch is 0.15-0.25 g / cm 3 ; The hydrophobic angle is greater than 120°.

10. Use of the silica aerogel masterbatch according to claim 9 in thermal insulation fillers and / or resin additives.

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