阅读说明：本技术 一种高强度纳米隔热材料及其制备方法 (High-strength nano heat-insulating material and preparation method thereof ) 是由 安烜熜 张凡 李文静 杨洁颖 张昊 孔德隆 于 2019-11-12 设计创作，主要内容包括：本发明涉及一种高强度纳米隔热材料及其制备方法。所述方法包括：(1)将纳米粉体与胶黏剂混合均匀,得到胶黏剂/纳米粉体；(2)将所述胶黏剂/纳米粉体、无机纤维和填料混合均匀,得到混合料；(3)将所述混合料进行铺料和模压,再经高温处理,制得高强度纳米隔热材料。本发明方法将胶黏剂加入纳米粉体中并通过合理设计胶黏剂与纳米粉体的配比,以及无机填料的配比,在不影响纳米隔热材料的隔热性能以及使用温度的前提下,实现了对纳米隔热材料力学性能的增强,提升了纳米隔热材料的机械加工性能。(The invention relates to a high-strength nano heat-insulating material and a preparation method thereof. The method comprises the following steps: (1) uniformly mixing the nano powder with an adhesive to obtain the adhesive/nano powder; (2) uniformly mixing the adhesive/nano powder, the inorganic fiber and the filler to obtain a mixture; (3) and (3) paving and die pressing the mixture, and then performing high-temperature treatment to obtain the high-strength nano heat-insulating material. According to the method, the adhesive is added into the nano-powder, and the proportion of the adhesive and the nano-powder and the proportion of the inorganic filler are reasonably designed, so that the mechanical property of the nano-thermal insulation material is enhanced and the mechanical processing property of the nano-thermal insulation material is improved on the premise of not influencing the thermal insulation property and the use temperature of the nano-thermal insulation material.)

1. The preparation method of the high-strength nanometer heat-insulating material is characterized by comprising the following steps of:

(1) uniformly mixing the nano powder with an adhesive to obtain the adhesive/nano powder;

(2) uniformly mixing the adhesive/nano powder, the inorganic fiber and the filler to obtain a mixture;

(3) and (3) paving and die pressing the mixture, and then performing high-temperature treatment to obtain the high-strength nano heat-insulating material.

2. The method of claim 1, wherein:

the adhesive is selected from one or more of silicate resin, phosphate resin, sodium silicate aqueous solution, silica sol and aluminum sol.

3. The method of claim 1, wherein:

the amount of the adhesive is 5-50 wt% of the amount of the nano powder.

4. The method of claim 1, wherein:

the temperature of the high-temperature treatment is 80-150 ℃, and the time of the high-temperature treatment is 1-5 h.

5. The production method according to any one of claims 1 to 4, characterized in that:

the particle size of the nano powder is 1-50 nm;

the diameter of the inorganic fiber is 1-10 um; and/or

The particle size of the filler is 1-20 um.

6. The production method according to any one of claims 1 to 4, characterized in that:

the nano powder is selected from one or more of nano silicon dioxide, nano aluminum oxide, nano zirconium oxide and nano aerogel;

the inorganic fiber is selected from one or more of high silica fiber, quartz fiber, mullite fiber, alumina silicate fiber and basalt stone wool fiber; and/or

The filler is selected from one or more of silicon carbide, silicon nitride, boron nitride, titanium dioxide, carbon powder, chromium oxide and talcum powder.

7. The production method according to any one of claims 1 to 4, characterized in that:

the pressure intensity of the die pressing is 2-20 MPa.

8. The production method according to any one of claims 1 to 4, characterized by further comprising, in step (3), after the mixture is subjected to the paving and molding in this order, a step of holding pressure before the high-temperature treatment: the pressure of the pressure maintaining is the same as that of the mould pressing, and the pressure maintaining time is 1-60 min.

9. The high-strength nano heat insulating material manufactured by the manufacturing method of any one of claims 1 to 8.

10. The high strength nano thermal insulation material of claim 9, wherein:

the density of the high-strength nano heat-insulating material is 0.3-1.0 g/cm³The room temperature thermal conductivity is 0.025-0.068W/m.K.

Technical Field

The invention relates to the technical field of heat insulation materials, in particular to a high-strength nano heat insulation material and a preparation method thereof.

Background

The nanometer heat insulating material has the characteristics of low density, high porosity, low heat conductivity and the like, and has excellent heat insulating performance. At present, two methods are mainly used for preparing the nano heat insulation material, one method is to take nano powder, reinforced fiber, opacifier, sintering aid and the like as raw materials, fully and uniformly mix the raw materials and then press and form the raw materials by mould pressing; the other method is to prepare the aerogel material by supercritical drying by a sol-gel method. The sol-gel method for preparing the nano heat-insulating material mainly comprises the steps of precursor hydrolysis, precursor gel, gel solvent replacement, gel supercritical drying and the like, belongs to chemical reaction, active hydroxyl groups formed after the precursor hydrolysis are difficult to be completely condensed under given conditions of gel, but condensation dehydration can be carried out on active sites at higher temperature, the macroscopic expression is that the skeleton of the aerogel shrinks and collapses, and the heat-insulating performance is sharply reduced at the temperature. The preparation of the nano heat-insulating material by a compression molding method mainly comprises the steps of fiber/powder mixing, mixture compression molding and the like, belongs to a physical process, and although the surface active sites of nano particles forming a heat-insulating material framework are few, the nano heat-insulating material prepared by compression molding generally has the problems of low mechanical strength, poor integrity and the like, so that the popularization and application of the nano heat-insulating material in engineering are limited.

Chinese patent application CN104210151A discloses a surface-strengthened high-temperature-resistant nano heat-insulating material and a preparation method thereof; the surface-reinforced high-temperature-resistant nano heat-insulating material consists of an internal nano heat-insulating material and a surface reinforcing layer, wherein the internal heat-insulating material is a granular porous heat-insulating material or a fiber-reinforced aerogel material, and the surface reinforcing layer is mainly inorganic fiber cloth or inorganic fiber cloth reinforced resin; however, the material is only surface-reinforced, and the whole material is not reinforced, and the prepared surface-reinforced high-temperature-resistant nano heat-insulating material still has the problems of low mechanical strength of the internal structure of the material, poor material integrity and easy damage to the content structure of the material due to the internal structure characteristics of the material.

In view of the above problems, it is very necessary to provide a high-strength nano heat insulating material and a method for preparing the same to solve the problem of poor strength of the conventional nano heat insulating material prepared by compression molding.

Disclosure of Invention

The invention provides a high-strength nano heat-insulating material and a preparation method thereof, aiming at solving the technical problem of poor strength of the existing nano heat-insulating material prepared by compression molding. The high-strength nano heat-insulating material prepared by the method has the advantages of high strength, good integrity, no damage to the internal structure of the material, no influence on the heat-insulating property and the use temperature of the material and the like.

The present invention provides, in a first aspect, a method for preparing a high-strength nano heat insulating material, the method comprising the steps of:

(1) uniformly mixing the nano powder with an adhesive to obtain the adhesive/nano powder;

(2) uniformly mixing the adhesive/nano powder, the inorganic fiber and the filler to obtain a mixture;

(3) and (3) paving and die pressing the mixture, and then performing high-temperature treatment to obtain the high-strength nano heat-insulating material.

Preferably, the adhesive is selected from one or more of silicate resin, phosphate resin, sodium silicate aqueous solution, silica sol and aluminum sol.

Preferably, the amount of the adhesive is 5-50 wt% of the amount of the nano powder.

Preferably, the temperature of the high-temperature treatment is 80-150 ℃, and the time of the high-temperature treatment is 1-5 h.

Preferably, the particle size of the nano powder is 1-50 nm; the diameter of the inorganic fiber is 1-10 um; and/or the particle size of the filler is 1-20 um.

Preferably, the nanopowder is selected from one or more of nano-silica, nano-alumina, nano-zirconia and nano-aerogel; the inorganic fiber is selected from one or more of high silica fiber, quartz fiber, mullite fiber, alumina silicate fiber and basalt stone wool fiber; and/or the filler is selected from one or more of silicon carbide, silicon nitride, boron nitride, titanium dioxide, carbon powder, chromium oxide and talcum powder.

Preferably, the pressure of the die pressing is 2-20 MPa.

Preferably, the method further comprises the step of maintaining the pressure after the mixture is sequentially paved and molded in the step (3) and before the high-temperature treatment: the pressure of the pressure maintaining is the same as that of the mould pressing, and the pressure maintaining time is 1-60 min.

The present invention provides, in a second aspect, a high-strength nano heat insulating material produced by the production method according to the first aspect of the present invention.

Preferably, the density of the high-strength nano heat-insulating material is 0.3-1.0 g/cm³The room temperature thermal conductivity is 0.025-0.068W/m.K.

Compared with the prior art, the invention at least has the following beneficial effects:

(1) the method comprises the steps of uniformly mixing nano powder with an adhesive to obtain an adhesive/nano powder, and carrying out mould pressing, assembly forming and high-temperature treatment on the mixed adhesive/nano powder under the action of fiber reinforcement to obtain a high-strength nano heat insulation material; according to the method, the adhesive is added into the nano-powder, and the proportion of the adhesive and the nano-powder and the proportion of the inorganic filler are reasonably designed, so that the mechanical property of the nano-thermal insulation material is enhanced and the mechanical processing property of the nano-thermal insulation material is improved on the premise of not reducing the thermal insulation property and the use temperature of the nano-thermal insulation material.

(2) The high-strength nano heat-insulating material mainly comprises nano powder, inorganic fibers, inorganic filler and adhesive, is a porous heat-insulating block material, and has the advantages of high temperature resistance, low heat conductivity, short preparation period, excellent machining performance and the like; compared with the sol-gel nano heat-insulating material, the material has simple preparation method, does not need to use an organic solvent and has high safety; compared with the existing compression molding nanometer heat-insulating material, the material has better mechanical strength while the heat-insulating property and the service temperature are not influenced, the integrity of the material is better, the internal structure of the material is not easy to damage, the structural stability is better, and the processing of complex sample pieces can be carried out.

(3) The high-strength nano heat-insulating material prepared by the invention has the advantages of easy component design and capability of better realizing the regulation and control of material performance.

(4) The design idea of the high-strength nanometer heat-insulating material component can be used for designing the performance of other fiber powder composite materials, and has universality.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The present invention provides, in a first aspect, a method for preparing a high-strength nano heat insulating material, the method comprising the steps of:

(1) uniformly mixing the nano powder with an adhesive to obtain the adhesive/nano powder;

(2) uniformly mixing the adhesive/nano powder, the inorganic fiber and the filler to obtain a mixture (a fiber/powder material);

(3) spreading and molding (mold assembly) the mixture, and then performing high-temperature treatment to prepare the high-strength nano heat-insulating material; in the material paving process, the material paving uniformity in the die is ensured; specifically, in the step (3), the mixture is spread and molded to obtain a high-strength nano heat-insulating material blank, the high-strength nano heat-insulating material blank is subjected to high-temperature treatment to ensure that the adhesive is cured, and meanwhile, the moisture in the product is dried to obtain the high-strength nano heat-insulating material.

At present, the common knowledge of the prior art on heat insulation materials is that the common high-performance heat insulation materials generally have a nano-pore structure and are prepared by adopting nano-structure units through sol-gel, physical assembly or other assembly modes; and the introduction of adhesives such as resin and the like into the nano heat-insulating material can affect the nano pore structure, thereby reducing the heat-insulating property and the use temperature of the nano heat-insulating material. The Chinese patent application CN104210151A prepares a surface-strengthened high-temperature-resistant nano heat-insulating material; the surface-reinforced high-temperature-resistant nano heat-insulating material is composed of an internal nano heat-insulating material and a surface reinforcing layer, wherein the internal heat-insulating material is a granular porous heat-insulating material or a fiber-reinforced aerogel material, the surface reinforcing layer is mainly made of inorganic fiber cloth or inorganic fiber cloth reinforced resin, the application of the patent only uses the resin on the low-temperature surface of the heat-insulating material and only reinforces the surface of the material in order to not influence the heat-insulating property and the use temperature of the nano heat-insulating material, but the surface-reinforced high-temperature-resistant nano heat-insulating material prepared by the application of the patent still has the problems of low mechanical strength of the internal structure of the material, poor integrity of the material and easy damage of the content structure of the material due to. The method adds the adhesive into the nano-powder, reasonably designs the proportion of the adhesive and the nano-powder and the proportion of a sintering aid (such as boron nitride) in the inorganic filler, enhances the mechanical property of the nano-thermal insulation material on the premise of not reducing the thermal insulation property and the use temperature of the nano-thermal insulation material, and improves the mechanical strength and the machinability of the nano-thermal insulation material.

The method solves the technical problem of poor strength of the existing compression molding preparation of the nano heat-insulating material; specifically, the method comprises the steps of firstly mixing nano powder and an adhesive according to a certain proportion, uniformly mixing the mixed adhesive/nano powder with an inorganic filler and inorganic fibers, carrying out compression molding, and finally carrying out high-temperature treatment to obtain the high-strength nano heat insulation material. The high-strength nano heat-insulating material prepared by die pressing assembly has no interlayer cracks, and the density deviation in the thickness direction is within 5 percent. The high-strength nano heat-insulating material prepared by the invention can meet the heat-insulating requirements of national defense, military industry and national economic main battlefield, is a high-efficiency heat-insulating material and can realize the improvement of the mechanical property of the nano heat-insulating material.

According to some preferred embodiments, the mixture consists of 60 to 85% (60%, 65%, 70%, 75%, 80% or 85%) by weight of the adhesive/nanopowder, 5 to 20% (5%, 10%, 15% or 20%) by weight of the inorganic fiber and 4 to 20% (e.g. 4%, 5%, 10%, 15% or 20%) by weight of the filler; the mixture in the proportion can more effectively ensure the uniformity of paving materials and is more favorable for preparing the high-strength nano heat-insulating material with more excellent comprehensive performance.

According to some preferred embodiments, the binder is selected from one or more of silicate resins (e.g. sodium silicate resins), phosphate resins (e.g. aluminium phosphate resins), aqueous sodium silicate solutions, silica sols, aluminium sols.

In the invention, the adhesive is preferably an inorganic adhesive, and compared with an organic resin adhesive, the inorganic adhesive can be carbonized at high temperature, so that the interior of the material structure is slightly changed, the material structure can be well used in a low-temperature environment, and the heat insulation performance of the nano heat insulation material can be reduced at high temperature.

According to some preferred embodiments, the amount of the adhesive is 5 to 50 wt% (mass percentage) of the amount of the nano-powder (e.g., 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%). In the invention, the preferable dosage of the adhesive is 5-50 wt% of the dosage of the nano powder, and the more preferable dosage is 10-30 wt%, and the invention improves the mechanical property of the nano heat-insulating material well on the premise of not reducing the heat-insulating property and the use temperature of the high-strength nano heat-insulating material by reasonably designing the mass ratio of the adhesive to the nano powder, so that the high-strength nano heat-insulating material with better structural stability is prepared. In the invention, the adhesive is an inorganic resin solution, and the forming process and the like are influenced by too large content of the adhesive; the inventor finds that the dosage of the adhesive is more preferably 10-30 wt% of the dosage of the nano powder, and the dosage of the adhesive with the more preferable proportion does not cause obvious adverse effect on the heat insulation performance of the nano heat insulation material.

According to some preferred embodiments, the high temperature treatment is carried out at a temperature of 80 to 150 ℃ (e.g., 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃, 145 ℃ or 150 ℃), and the high temperature treatment is carried out for a time of 1 to 5 hours (e.g., 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5 hours).

According to some preferred embodiments, the particle size of the nano powder is 1-50 nm; the diameter of the inorganic fiber is 1-10 um; and/or the particle size of the filler is 1-20 um.

According to some preferred embodiments, the nanopowder is selected from one or more of nanosilica, and nanoaerogel; the inorganic fiber is selected from one or more of high silica fiber, quartz fiber, mullite fiber, alumina silicate fiber and basalt stone wool fiber; and/or the filler is selected from one or more of silicon carbide, silicon nitride, boron nitride, titanium dioxide, carbon powder, chromium oxide and talcum powder.

According to some more preferred embodiments, the filler comprises a filler component selected from one or more of silicon carbide, silicon nitride, titanium dioxide, carbon powder, chromium oxide, talc and a sintering aid component which is boron nitride; the amount of the sintering aid component is 20-40 wt% (mass percent) of the amount of the filler (the total amount of the filler component and the sintering aid component) (for example, 20 wt%, 25 wt%, 30 wt%, 35 wt%, or 40 wt%); in the invention, the filler preferably further comprises a sintering aid component, and the amount of the sintering aid component is 20-40 wt% of the total amount of the filler component and the sintering aid component. The inventor finds that the content of boron nitride does not influence the heat insulation performance of the nano heat insulation material per se through testing, the content of boron nitride only influences the mechanical strength of a product as a sintering aid, but when the mass ratio of boron nitride is larger, the content of other components is relatively reduced, for example, the content of anti-radiation filler is relatively reduced, so that the high-temperature heat insulation performance of the product is reduced; the inventor finds that when the content of boron nitride is high, the product strength is high, and the method can be used in occasions with high requirements on machining size precision; the dosage of the sintering aid is preferably 20-40% of the dosage of the filler, and the proportion does not have obvious adverse effect on the heat insulation performance of the nano heat insulation material product.

According to some preferred embodiments, the pressure of the molding is 2 to 20MPa (e.g. 2, 5, 10, 15 or 20 MPa); in the present invention, the speed of the molding may be, for example, 0.1 to 50mm/s (e.g., 0.1, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 mm/s). In the present invention, the mold assembly of the high-strength nano heat insulating material may be performed, for example, using a press or an apparatus capable of providing an equivalent pressure.

According to some preferred embodiments, the method further comprises a step of maintaining pressure after the mixture is sequentially paved and molded in the step (3) before the high-temperature treatment: the pressure of the pressure maintaining is the same as that of the mould pressing, and the pressure maintaining time is 1-60 min (such as 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 min); according to the invention, the mixture is paved and molded, after the mixture is molded to a set thickness, a high-strength nano heat insulation material blank is obtained, and then the high-strength nano heat insulation material blank is subjected to pressure maintaining for 1-60 min and then subjected to high-temperature treatment, so that the high-strength nano heat insulation material is prepared.

According to some preferred embodiments, the thickness of the high-strength nano heat insulation material is 2 to 200mm, preferably 5 to 150 mm.

According to some specific embodiments, the high-strength nano heat insulating material is prepared by the following steps:

s1, weighing nano powder, inorganic fibers, adhesives, fillers and the like according to the proportion for later use;

s2, firstly, putting the nano powder into a mixer, gradually and slowly adding the adhesive, ensuring that the nano powder and the adhesive are fully mixed to obtain adhesive/nano powder (adhesive/nano powder mixture), for example, through reasonable component design, uniformly mixing the nano powder and the adhesive under the action of powerful mixing and dispersing (for example, under the action of powerful mixing and dispersing of mechanical fusion equipment);

s3, gradually adding inorganic fibers into the adhesive/nano powder mixture, uniformly mixing, and then adding inorganic fillers to ensure that uniform fiber/powder materials are finally obtained;

s4, spreading and die pressing the mixed fiber/powder material to obtain a high-strength nano heat-insulating material blank, and controlling the structural integrity and density of the material by adjusting the die pressing pressure and the pressure maintaining time; numbering and weighing the formed high-strength nano heat-insulating material blank.

And S5, performing high-temperature treatment on the molded high-strength nano heat-insulating material blank, cooling to room temperature, taking out, and weighing for later use to obtain the high-strength nano heat-insulating material.

The present invention provides, in a second aspect, a high-strength nano heat insulating material produced by the production method according to the first aspect of the present invention. The high-strength nano heat-insulating material mainly comprises nano powder, inorganic fibers, inorganic filler and adhesive, is a porous heat-insulating block material, and has the advantages of high temperature resistance, low heat conductivity, short preparation period, excellent machining performance and the like; compared with the sol-gel nano heat-insulating material, the material has simple preparation method, does not need to use an organic solvent and has high safety; compared with the existing compression molding nanometer heat-insulating material, the material has better mechanical strength while the heat-insulating property and the service temperature are not influenced, the integrity of the material is better, the internal structure of the material is not easy to damage, the structural stability is better, and the processing of complex sample pieces can be carried out.

According to some preferred embodiments, the high-strength nano heat insulating material has a density of 0.3 to 1.0g/cm³The room temperature thermal conductivity is 0.025-0.068W/m.K.

The invention will be further illustrated by way of example, but the scope of protection is not limited to these examples.