CN107387944B

CN107387944B - Environment-friendly vacuum insulation board

Info

Publication number: CN107387944B
Application number: CN201710505291.3A
Authority: CN
Inventors: 高彦峰; 卢健; 危韦; 赵起
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-06-28
Filing date: 2017-06-28
Publication date: 2020-01-10
Anticipated expiration: 2037-06-28
Also published as: CN107387944A

Abstract

The invention relates to an environment-friendly vacuum insulation board, which comprises an insulation core material positioned at the inner side, a reflection type air barrier diaphragm positioned at the outer side, and a protective layer positioned between the insulation core material and the reflection type air barrier diaphragm; the heat insulation core material comprises 40-95 wt% of glass fiber, 2-40 wt% of diatomite, 2-40 wt% of attapulgite and 1-5 wt% of binder. The diatomite, attapulgite and glass fiber composite core board is adopted, so that the problem of vacuum degree reduction caused by the damage of the packaging bag can be avoided, the process flow can be simplified, and the production cost of the core material can be reduced.

Description

Environment-friendly vacuum insulation board

Technical Field

The invention relates to an environment-friendly vacuum heat-insulating plate and a manufacturing method thereof, belonging to the field of heat-insulating materials.

Background

Vacuum thermal insulation panels (VIP) are one of Vacuum insulation materials, are formed by compounding a filling core material and a Vacuum protection surface layer, and have been widely applied to the industries of aerospace, household appliances, buildings and the like because the thermal insulation performance of the Vacuum thermal insulation panels is far superior to that of the traditional polyurethane materials. On one hand, the vacuum insulation board can effectively avoid heat transfer caused by air convection, and on the other hand, the core material with extremely low thermal conductivity is adopted to prevent heat conduction from going on to a great extent, so that the thermal conductivity of the VIP board can be greatly reduced and is less than 0.035 w/(m.k).

Most of the core materials of vacuum insulation panels sold in the market at present are made of porous medium materials, such as glass fiber, aerogel, powdered silicon dioxide and the like, and any one of the core materials has advantages and disadvantages. Secondly, in the process of manufacturing the heat insulation core plate, a certain amount of drying agent or getter must be added to remove the gas and moisture which are not completely removed in the barrier film and the core plate, so as to keep relatively high vacuum degree, thereby prolonging the service life of the vacuum heat insulation plate.

The vacuum insulation panel core material must have the following four characteristics: the core material is in a high vacuum negative pressure state, and a support structure is required to be arranged to prevent the vacuum insulation panel from shrinking and invaginating. Secondly, its structural design must reduce heat conduction as much as possible. The core plate must then have a sufficient number of open structures to allow the gas to be discharged at the fastest rate under negative pressure. Finally, the material must be sufficiently stable to release no or as little gas as possible under vacuum or ultra-low vacuum conditions.

For improving the heat insulation performance of the heat insulation board, three heat transfer modes must be considered, wherein when the temperature difference between the ambient temperature and the inside of the heat insulation box exceeds 30 ℃, the influence of radiation heat transfer cannot be ignored. Especially, the proportion occupied by the insulation box using the insulation core material is even more than 35% of the total heat transfer. However, the conventional patent is rarely regarded as important in the design of the heat insulating plate. CN105058541A discloses a cork powder-based porous composite material and a preparation method and application thereof, belonging to the field of heat insulation materials, wherein cork powder and fumed silica are adopted as main raw materials, the preparation method comprises the following steps of selecting cork powder with a certain particle size, carrying out structure reforming on the cork powder by a microwave pretreatment method, mixing the structure reformed cork powder with the fumed silica to obtain composite powder, and applying pressure for one ton for a certain time for one minute to obtain the cork powder-based porous composite material, but the defect is that the used core material is silica aerogel, and because 99% of the material is composed of gas, collapse can occur along with the prolonging of the service time, the volume is obviously reduced, and the heat insulation performance is poor. CN105757400A discloses a glass fiber based vacuum insulation panel, wherein a core material of the panel is mainly formed by arranging ultrafine glass fiber cotton sheets on the upper and lower sides of a chopped strand core material (a laminated layer of wet-formed chopped strand sheets), or a glass fiber mat core material of a dry-process glass fiber mat, or a core material containing both the wet-formed chopped strand sheets and the dry-process glass fiber mat, but the panel has the defect that the ultrafine glass fiber cotton sheets still have the possibility that some glass fibers puncture a vacuum bag to reduce the vacuum degree.

Disclosure of Invention

In view of the above problems, the present invention provides an environment-friendly vacuum insulation panel, comprising a heat insulation core material located at the inner side, a reflective type gas barrier membrane located at the outer side, and a protective layer located between the heat insulation core material and the reflective type gas barrier membrane;

the heat insulation core material comprises 40-95 wt% of glass fiber, 2-40 wt% of diatomite, 2-40 wt% of attapulgite and 1-5 wt% of binder.

According to the invention, 40-95 wt% of glass fiber, 2-40 wt% of diatomite and 2-40 wt% of attapulgite are selected as materials of the heat insulation core material, on one hand, the glass fiber with low heat conductivity is selected as a main material of the heat insulation core material, so that the heat insulation effect can be greatly improved, on the other hand, the plasticity of the core material can be increased by adding industrial wastes of diatomite and attapulgite, so that the compression molding of the core material is facilitated, the problem of vacuum degree reduction caused by the fact that the glass fiber punctures the packaging bag can be effectively prevented, meanwhile, the waste recycling is realized, and the production cost is reduced. In addition, when the glass fiber cotton is mixed with powder such as diatomite, attapulgite and the like, the order of magnitude of holes and pores on the surface of the glass fiber cotton is equivalent to the mean free path of air molecules, so that the heat conduction in the material can be greatly reduced.

Preferably, the heat insulation core material comprises a glass fiber heat insulation layer made of the glass fiber and mixed layers made of diatomite and attapulgite and positioned on the upper surface and the lower surface of the glass fiber heat insulation layer. That is to say, the diatomite and the attapulgite are pressed on the two sides of the glass fiber heat-insulating layer, so that the problem that the glass fiber punctures the packaging bag can be effectively solved.

Preferably, the thickness of the glass fiber heat-insulating layer is 5-30 mm, and the thickness of the mixing layer is 2-20 mm.

Preferably, the mass ratio of the diatomite to the attapulgite in the mixed layer is (1-20): (1-20).

Preferably, the average diameter of the glass fiber in the glass fiber heat-insulating layer is 10 μm, and the length-diameter ratio is more than 500: 1.

also, preferably, the size of the diatomite and the attapulgite is between 300 meshes and 800 meshes. According to the invention, the diatomite and the attapulgite with the particle size of 300-800 meshes are selected as the protective layers, so that the beneficial effect of preventing the membrane bag from being punctured is achieved.

Preferably, the material of the reflection-type gas barrier diaphragm is a composite material of PE and CPP, the surface of the reflection-type gas barrier diaphragm is plated with a metal film, and the overall thickness of the reflection-type gas barrier diaphragm is 0.01-1 mm. The invention adopts the mode of replacing the traditional aluminum plate with the flexible diaphragm of the high-reflection metal coating, effectively prevents the radiation and the conduction of heat, greatly limits the phenomenon of the reduction of the heat preservation performance caused by the radiation heat transfer, and even can be made into a flexible heat preservation material. And the outer side surface of the air-blocking diaphragm is coated with a metal film, and because the inner sides of the air-blocking diaphragms at the upper side and the lower side are PE and CPP, the heat conductivity is extremely low, and the bad phenomenon of thermal bridge generation caused by adopting an aluminum plate can not occur.

Preferably, the metal film is one of silver, aluminum, nickel, copper and alloys thereof, and has a thickness of 50 to 500 nm.

Preferably, the protective layer is a fiber filter bag, the porosity of the protective layer is greater than 80%, and the pore diameter is 0.1-50 μm, so that the glass fiber can not be drawn out, and the overall vacuum degree in the reflective gas barrier diaphragm is lower than 0.3MPa without interfering with the vacuum-pumping treatment in the preparation process of the vacuum insulation board.

Drawings

FIG. 1 is a schematic view of an environmentally friendly vacuum insulation panel;

FIG. 2 is a schematic structural view of an incubator formed by inserting the environmentally friendly vacuum insulation panel of the present invention into six facing layers of a double-layered polypropylene plastic box;

FIG. 3 is a temperature profile of a cold insulation test of the double insulated cabinets prepared in examples 1 and 2 and comparative example 1;

FIG. 4 is a temperature profile of the insulation test of the double insulated boxes prepared in examples 1 and 2 and comparative example 1.

Detailed Description

The present invention is further illustrated by the following examples, which are to be understood as merely illustrative and not restrictive.

The environment-friendly vacuum heat insulation plate (vacuum heat insulation plate) consists of a heat insulation core material and a reflection type choke diaphragm. The heat insulation core material is a block body consisting of glass fiber, diatomite and attapulgite. The vacuum insulation panel also comprises a protective layer for preventing the core material powder from being extracted.

The heat insulation block (heat insulation core material) can be formed by pressing a plurality of heat insulation materials (glass fiber, diatomite and attapulgite industrial waste) according to a certain proportion. The mass percentage of the glass fiber is 40-95 wt%, preferably 55-80 wt%, based on the total mass of the heat insulation core material as 100%; the content of each of the diatomite and the attapulgite is 2-40 wt%, preferably 10-20 wt%. The glass fiber, the diatomite and the attapulgite can be mixed and then pressed, but the preferable scheme is that the diatomite and the attapulgite are mainly distributed on the upper side and the lower side (more preferably around) of the glass fiber and then pressed. The whole thickness of the heat insulation core material can be 5-30 mm, wherein the thickness of the heat insulation layer formed by the glass fiber can be 3-20 mm, and the thickness of the mixing layer formed by the diatomite and the attapulgite can be 2-20 mm. In the mixed layer, the mass ratio of the diatomite to the attapulgite can be (1-20): (1-20). The heat insulation core material further comprises a binder which accounts for less than 5wt% of the total mass, preferably 1-5 wt%, and is used for binding the glass fiber, the diatomite and the attapulgite together to form a block structure. In the invention, the size of the diatomite and the attapulgite can be selected from 300 meshes to 800 meshes. The glass fibers have an average diameter of about 10 μm, an aspect ratio of greater than 500: 1. the binder can be epoxy resin.

The protective layer can be a bag structure, such as a fiber filter bag, which is a non-woven fabric, the bag thickness is less than 100 μm, the material is fiber material, the porosity is greater than 80%, and the pore diameter is about 0.1-50 μm. The filter bag is tightly attached to the heat insulation core material and wraps the heat insulation core material.

The protective layer is further covered with a reflective gas barrier membrane (preferably formed in a bag, i.e., a reflective gas barrier membrane bag) having a vacuum degree maintaining function, the surface of the gas barrier membrane bag is plated with a metal thin film (e.g., silver, aluminum, nickel, copper, or an alloy thereof) to improve the heat radiation reflection efficiency, the thickness of the reflective gas barrier membrane as a whole may be 0.01 to 1mm, and the thickness of the metal thin film plated thereon may be 50 to 500 nm. The heat radiation reflection efficiency is more than 90%. The vacuum degree in the reflection type gas barrier diaphragm bag is lower than 0.3 MPa. The thermal conductivity coefficient of the whole vacuum insulation panel is less than 0.02W/(m.k). The material of the reflection-type gas barrier diaphragm bag can be formed by compounding two materials of PE and CPP.

Referring to fig. 1, which shows an exemplary structure diagram of the environment-friendly vacuum insulation panel of the present invention, from outside to inside, the environment-friendly vacuum insulation panel comprises a silver-plated reflective barrier film 1, a fiber filter film 2, and insulation core materials 3 and 4, wherein 3 is mainly a mixed layer of diatomite and attapulgite, and 4 is mainly a glass fiber insulation layer.

As an example of a method for preparing an environmentally friendly vacuum insulation panel, the method comprises the following steps: weighing glass fiber, diatomite and attapulgite according to a certain proportion, firstly taking the glass fiber as a central material, paving the diatomite and the attapulgite in a manner of wrapping the glass fiber, bonding the glass fiber, the diatomite and the attapulgite by means of a binder, and pressing (the pressing pressure can be 20-80 MPa) to form a block material as a heat insulation core material (core material); filling the core material into a fiber filter bag with porosity of more than 80% and pore diameter of about 0.1-50 μm, and sealing; and (3) putting the fiber filter bag with the core material into a reflection gas barrier diaphragm bag with the surface plated with aluminum, vacuumizing and packaging to obtain the vacuum heat insulation plate. At this time, the whole vacuum degree in the vacuum heat insulation plate is lower than 0.3 MPa.

The diatomite, attapulgite and glass fiber composite core board is adopted, so that the problem of vacuum degree reduction caused by the damage of the packaging bag can be avoided, the process flow can be simplified, and the production cost of the core material can be reduced. The invention adopts the mode of replacing the traditional aluminum plate with the high-reflection metal coating, effectively prevents radiation heat transfer, and can even be made into flexible heat-insulating materials.

The present invention will be described in further detail with reference to examples. It is also to be understood that the following examples are illustrative of the present invention and are not to be construed as limiting the scope of the invention, and that certain insubstantial modifications and adaptations of the invention by those skilled in the art may be made in light of the above teachings. The specific process parameters and the like of the following examples are also only one example of suitable ranges, i.e., those skilled in the art can select the appropriate ranges through the description herein, and are not limited to the specific values exemplified below. In the following examples, unless otherwise specified, the average diameter of the glass fibers in the glass fiber insulation layer is 10 μm, the length-diameter ratio is more than 500, and the size of the diatomite and the attapulgite is between 300 meshes and 800 meshes.

Example 1

An environment-friendly vacuum insulation panel and a preparation method thereof are disclosed:

firstly, mixing 58 wt% of glass fiber, 20 wt% of diatomite and 20 wt% of attapulgite to ensure that the diatomite and the attapulgite are paved on the outer side of the glass fiber;

adding an adhesive (epoxy resin) accounting for 2 wt% of the total mass into the raw materials to bond the raw materials together;

pressing the raw materials bonded together into a block body with the thickness of 30mm under the condition of 50MPa, wherein the thickness of the glass fiber heat-insulating layer is 20mm, and the thickness of a mixed layer of diatomite and attapulgite distributed on two sides of the glass fiber heat-insulating layer is 10 mm;

putting the pressed block into a fiber filter bag (the porosity is more than 80%, and the pore diameter is 0.1-50 mu m), and putting the block into a reflection type gas barrier diaphragm bag (the surface of the reflection type gas barrier diaphragm bag is coated with an aluminum film, the thickness of the reflection type gas barrier diaphragm bag is 0.25mm, and the thickness of a metal film is 120 nm);

vacuumizing to ensure that the vacuum degree is below 0.3MPa, and packaging to obtain the vacuum insulation board.

The prepared vacuum insulation panels were inserted into six-sided sandwich of a 35.4cm by 26.0cm by 28.8cm double layer polypropylene plastic box (see fig. 2) to form an incubator (dimensions shown in the table below):

6kg of refrigerant was placed (about 1/3 load) in an incubator to ensure the container was sealed and the ambient temperature was 23 degrees Celsius, and the temperature of the refrigerant and heat source surfaces was tested as a function of time (see the curves shown in example 1 in FIGS. 3 and 4, respectively).

Example 2

firstly, mixing 78 wt% of glass fiber, 10wt% of diatomite and 10wt% of attapulgite to ensure that the diatomite and the attapulgite are paved on the outer side of the glass fiber;

putting the pressed block into a fiber filter bag (the porosity is more than 80%, and the pore diameter is 0.1-50 mu m), and putting the block into a reflection type gas barrier diaphragm bag (the surfaces of the reflection type gas barrier diaphragm bags are coated with aluminum films, the thickness of the reflection type gas barrier diaphragm bag is 0.25mm, and the thickness of a metal film is 120 nm);

6kg of refrigerant was placed (about 1/3 load) in an incubator to ensure the container was sealed and the ambient temperature was 23 degrees Celsius, and the temperature of the refrigerant and heat source surfaces was tested as a function of time (see the curves shown in example 2 of FIGS. 3 and 4, respectively).

Comparative example 1

taking glass fiber, adding 2 wt% of binder (epoxy resin) to bond the raw materials together;

pressing the raw materials bonded together into a block with the thickness of 30mm under the condition of 50 MPa;

6kg of refrigerant was placed (about 1/3 load) in an incubator to ensure the container was sealed and the ambient temperature was 23 degrees Celsius, and the temperature of the refrigerant and heat source surfaces was tested as a function of time (see the curves shown in example 3 of FIGS. 3 and 4, respectively).

Referring to fig. 3 and 4, the insulation test effects of the incubators prepared in example 1 (example 1), example 2 (example 2) and comparative example (example 3) are shown: as can be seen from FIG. 3, the low temperature heat-insulating effect is the best in the embodiment example 2, the low temperature heat-insulating effect is the second best in the embodiment example 1, and the low temperature heat-insulating effect is the worst in the embodiment example 3. As can be seen from FIG. 4, the heat-insulating effect at high temperature is the best in the embodiment example 2, the heat-insulating effect at high temperature is the second best in the embodiment example 1, and the heat-insulating effect at high temperature is the worst in the embodiment example 3. The proper contents of the diatomite and the attapulgite also have certain influence on the heat preservation effect of the core material.

The above-mentioned embodiments are merely illustrative of the technical idea and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the scope of the present invention, and all equivalent changes or modifications made according to the spirit of the present invention should be covered in the scope of the present invention.

Claims

1. The vacuum insulation panel is characterized by comprising an insulation core material positioned on the inner side, a reflection type air barrier diaphragm positioned on the outer side, and a protective layer positioned between the insulation core material and the reflection type air barrier diaphragm; the heat insulation core material comprises a core material formed by mixing a material with the following components in percentage by weight, wherein the average diameter is 10 mu m, and the length-diameter ratio is more than 500: 1, and a mixed layer which is positioned on the upper surface and the lower surface of the glass fiber heat-insulating layer and is made of diatomite and attapulgite, wherein the size of the attapulgite is between 300 meshes and 800 meshes, and the size of the diatomite is between 300 meshes and 800 meshes;

the heat insulation core material comprises 78-95 wt% of glass fiber, 2-10 wt% of diatomite, 2-10 wt% of attapulgite and 2-5 wt% of binder.

2. The vacuum insulation panel according to claim 1, wherein the glass fiber insulation layer has a thickness of 5 to 30mm, and the mixed layer has a thickness of 2 to 20 mm.

3. The vacuum insulation panel according to claim 1, wherein the mass ratio of the diatomite to the attapulgite in the mixed layer is (1-20): (1-20).

4. The vacuum insulation panel according to claim 1, wherein the reflective type gas barrier membrane is made of a composite material of PE and CPP and is coated with a metal film, and the overall thickness of the reflective type gas barrier membrane is 0.01-1 mm.

5. The vacuum insulation panel according to claim 4, wherein the metal thin film is one of silver, aluminum, nickel, and copper and an alloy thereof, and has a thickness of 50 to 500 nm.

6. The vacuum insulation panel according to any of claims 1 to 5, wherein the protective layer is a fiber filter bag having a porosity of more than 80% and a pore size of 0.1 to 50 μm.