CN118361620A - Bearing-heat preservation integrated vacuum heat preservation container and preparation method thereof - Google Patents

Abstract

The invention discloses a bearing-heat preservation integrated vacuum heat preservation container and a preparation method thereof, wherein the vacuum heat preservation container comprises an inner container, a dry fiber gradient winding layer and a composite gas-barrier film, and the inner container and the composite gas-barrier film are connected through a container opening in an adhesive manner to form an intermediate vacuum cavity structure; the dry fiber gradient winding layer is made of dry fibers, a resin matrix is not contained, the fiber volume density is in gradient change, and each gradient layer adopts a geodesic winding mode. Compared with the traditional heat preservation container, the dry fiber gradient winding layer of the structure integrates the functions of bearing internal pressure and supporting a vacuum framework, integrates bearing and heat preservation functions, and is favorable for the weight reduction and the miniaturization of the heat preservation container.

Description

Bearing-heat preservation integrated vacuum heat preservation container and preparation method thereof

Technical Field

The invention belongs to the technical field of heat preservation containers, and particularly relates to a bearing-heat preservation integrated vacuum heat preservation container and a preparation method thereof.

Background

The heat preservation container such as a water heater not only has the heat preservation function, but also has to bear certain internal pressure load effect, and in order to ensure the bearing and heat preservation effect of the heat preservation container, most of the heat preservation containers adopt a double-structure design mode, namely, the inner container is used for bearing internal pressure and sealing, and the low heat conductivity coefficient material is externally added for improving the heat preservation performance.

In the prior art, the heat-insulating container usually adopts a technical process of a metal liner, heat-insulating foam or a high polymer material, a fiber reinforced resin matrix composite material winding layer and heat-insulating foam, and the internal pressure bearing and heat-insulating functions of the container are respectively realized.

Patent CN104374087a discloses a water heater liner, which is an integrally formed plastic liner substrate and a fiber layer fixedly connected to the outer surface of the plastic liner substrate. Not only is the resin-based (especially thermosetting) composite material structure heavy in weight, but also the problems that resin matrix is easy to crack, delaminate, fall off and the like to cause failure under the extreme environments of impact load or high and low temperature and the like, and the retired product is not easy to recycle and reuse, so that energy and material waste, environmental pollution and the like are caused.

Meanwhile, the currently mainstream heat-insulating materials mainly comprise gas-phase SiO ₂ or precipitated SiO ₂ particles, foam, glass fiber cotton and the like, the heat conductivity coefficients of the materials are relatively high, and the heat-insulating performance can not meet the energy-saving requirement. There are few applications of Vacuum Insulation Panels (VIP) in the building, transportation cases, and refrigerator, water heater directions, but this material has the disadvantages of easy damage and difficult processing during manufacturing and use operations, subject to material and process limitations.

Patent CN116817451a discloses a water heater liner with a vacuum heat-insulating structure, which comprises a first liner blown by plastic, a second liner made of fiber reinforced resin matrix material, and a vacuum cavity formed by the two liners. The first inner bag of blown plastics that this structure adopted hardly guarantees to bear interior pressure, and simultaneously, the bonding strength between the blown plastic layer of second inner bag and the resin-based fibre winding layer is lower, probably with there being the risk of layering inefficacy in the vacuum environment.

Therefore, in order to ensure both the structural strength and the insulation of the container, it is highly desirable to develop a structure that can be used for insulation of the container with excellent load-bearing and insulation properties.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides the bearing-heat preservation integrated vacuum heat preservation container and the preparation method thereof, and the container not only has the bearing performance of a high-pressure container, but also has a good heat preservation function, and realizes the structure and function integrated design of the container. In order to achieve the above object, the present invention provides the following technical solutions:

As a first aspect of the present invention, there is provided a load-and-heat-insulation integrated vacuum heat-insulation container, comprising a liner, a dry fiber gradient winding layer, and a composite gas-barrier film, wherein the liner and the composite gas-barrier film are bonded and connected through a liner opening to form an intermediate vacuum cavity structure; the dry fiber gradient winding layer comprises a plurality of gradient layers, the material is dry fiber, a resin matrix is not contained, the volume density of the fiber is in gradient change, and each gradient layer adopts a geodesic winding mode to avoid fiber yarn slipping; the liner structure of the heat preservation container comprises a barrel body and an end socket, the barrel body can be round or square, the liner is made of high polymer materials or made of stainless steel or enamel materials through a blow molding process, the high polymer materials comprise polyolefin materials such as polybutene and high-density polyethylene, and the blow molding process can adopt extrusion blow molding and injection blow molding processes.

The dry fiber gradient winding layer is wrapped on the outer side of the liner and comprises a tightly wound inner layer, a low-density winding layer and a tightly wound outer layer; the coverage rate of the fiber of the tightly wound inner layer and the tightly wound outer layer is 90% -100%, and the coverage rate of the fiber of the low-density winding layer is 10% -20%; the dry fibers at the two ends of the container are wound in a stepless hole winding mode and a polar hole winding mode respectively. The dry fiber adopts inorganic fiber or organic fiber, the inorganic fiber is selected from glass fiber, carbon fiber, basalt fiber and the like, the organic fiber is selected from aramid fiber, ultra-high molecular weight polyethylene fiber and the like, and the volume content of the whole fiber is 8-20%.

Preferably, the volume content of the tightly wound inner layer fiber is 70-80%, the tightly wound inner layer fiber is connected with the outer surface of the inner container, and the thickness can be designed into different values according to the requirements of the container, preferably in the range of 0.2-5 mm, and the tightly wound inner layer fiber mainly aims at improving the pressure bearing capacity of the inner container.

The winding line type of the tightly wound inner layer can select one or a mixed winding mode of circumferential winding and spiral winding, the circumferential winding angle can be selected from 80 degrees to 90 degrees, and the spiral winding angle can be selected from 0 degrees to 65 degrees.

Preferably, the low-density winding layer is tightly wound on the outer side of the inner layer and mainly plays a role of supporting a vacuum cavity of the inner container and the composite gas-barrier film, and the thickness can be designed according to practical conditions, so that the fiber coverage rate of the low-density winding layer is 6% -15%, and the fiber volume content of the middle fiber layer is ensured to be within 20%, preferably 5% -10%.

Further, the number of yarn bundles is adjusted to be 1/2-1/5 of that of the tightly wound inner layer when the low-density winding layer is wound, and the yarn width is designed to be 2-5 times that of the tightly wound inner layer. The winding line type can select one or a mixed winding mode of circumferential winding and spiral winding, the circumferential winding angle can be selected from 80 degrees to 90 degrees, and the spiral winding angle can be selected from 0 degrees to 65 degrees. In order to ensure that the fibers do not slide and are uniformly distributed, a geodesic winding path is adopted during winding, and technological parameters such as winding tension, yarn bundle width, polar hole diameter and the like are controlled.

Preferably, the tightly wound outer layer is connected with the inner surface of the composite gas-barrier film, the thickness is 0.2-5 mm, and the composite gas-barrier film is mainly supported so as not to deform under the action of vacuum pressure. The winding line type can select one or a mixed winding mode of circumferential winding and spiral winding, the circumferential winding angle can be selected from 80 degrees to 90 degrees, and the spiral winding angle can be selected from 0 degrees to 65 degrees.

Preferably, the composite gas-barrier film is wrapped on the outer side of the tightly wound outer layer and comprises a multi-layer film structure, wherein the multi-layer film structure comprises 0.1-0.3 mm of a high polymer material inner film, 0.04-0.1 mm of a vacuum aluminum plating film and 0.3-1 mm of a fiber reinforced thermoplastic composite material layer, which are consistent with the inner container material.

In the invention, the dry fiber gradient winding layer comprises a tightly wound inner layer, a low-density winding layer and a tightly wound outer layer, and simultaneously plays roles of improving the bearing internal pressure of the liner and supporting the vacuum cavity framework, thereby achieving the purpose of integrating the bearing-heat preservation function; the composite air-insulating film is of a multi-layer film composite structure, the innermost layer film material is the same as the liner material, a vacuum aluminized film and a fiber-reinforced thermoplastic composite material layer are outwards arranged, the vacuum aluminized film is formed by forming a compact aluminum layer on the surface of the innermost layer film, the air-insulating performance is obviously improved, and the fiber-reinforced thermoplastic composite material layer is mainly used for protecting the surfaces of the composite air-insulating film and a heat-insulating container and avoiding the influence of external collision on the structural vacuum degree.

Preferably, the heat preservation container is a water heater, a heat preservation storage tank or a food storage and transportation box.

The invention adopts a vacuum structure formed by a high polymer material liner, a dry fiber gradient winding layer and a composite gas-barrier film. The integrated bearing and heat-insulating structure ensures the bearing internal pressure function of the liner and improves the heat-insulating performance of the structure. The vacuum structure effectively reduces heat transmission, achieves good heat insulation effect, and meanwhile, the vacuum layer heat insulation material has no defects of moisture absorption, mildew, aging and the like of the common heat insulation material. The dry fiber gradient winding layer fully exerts the characteristic of strong designability of the composite material, and the parts close to the high polymer liner and the composite gas-barrier film are tightly wound so as to ensure that the liner structure can bear internal pressure load and the composite gas-barrier film is not deformed in the vacuum structure. The dry fiber winding does not use resin, so that environmental pollution caused by the fact that the material cannot be recovered in the later period is avoided.

As a second aspect of the present invention, there is provided a method for manufacturing the load-bearing-heat-insulating integrated vacuum heat-insulating container, comprising a blow molding process of a liner, a winding process of a dry fiber gradient winding layer, a laying process of a composite air-insulating film, and a vacuum-pumping process; wherein,

The blow molding process of the liner comprises the following steps: the liner material can be selected from polyolefin polymer materials such as polybutene, high-density polyethylene and the like, and is prepared from polyolefin granules: plastic plasticizer: an antioxidant: hardness control agent: pigment=75-85%, 5-15%, 1% and 5-15% are mixed, stirred in a stirrer at 90-120 deg.c and stoved for 4-12 hr, heated and molten in a blow molding machine, extruded at 190-250 deg.c, extrusion speed controlled at 10-25 m/min, blown into the mold cavity via the injection molding head at 160-190 deg.c and blowing at 60-80 deg.c, and cooled to form;

The winding process of the dry fiber gradient winding layer comprises the following steps: the dry fiber is wound in a single or mixed mode in 0-65 DEG spiral winding and 80-90 DEG circumferential winding, the end covers at the two ends are respectively wound in a stepless hole winding mode and a polar hole winding mode, the yarn width is controlled to be 3-40 mm, the number of winding layers of each winding angle is designed according to the requirements of a container, the winding tension is controlled to be 5-8% of the breaking force of the fiber bundle, and the yarn outlet speed is controlled to be 10-50 m/min.

Compared with the prior art, the invention has the beneficial effects that:

1) Compared with the foam heat preservation of the traditional container, the structure comprises a vacuum cavity formed by a multi-layer structure, and the vacuum cavity is supported by continuous dry fiber winding layers with different density gradients, so that the heat preservation function and stability of the container are improved;

2) Compared with a fiber reinforced resin matrix composite material winding container, the dry fiber gradient winding layer of the structure does not contain a resin matrix, so that the requirements of a wet winding process on workshop environment-friendly facilities are simplified, the problem of environmental pollution after the service period of the resin matrix composite material is avoided, and the production cost of the container is reduced;

3) Compared with the traditional heat preservation container, the dry fiber gradient winding layer of the structure integrates the functions of bearing internal pressure and supporting a vacuum framework, integrates bearing and heat preservation functions, and is favorable for realizing the light weight and the miniaturization of the heat preservation container.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.

FIG. 1 is a schematic cross-sectional view of a thermal insulation container provided by the invention;

FIG. 2 is a schematic view of a tightly wound layer structure in the insulated container provided by the invention;

FIG. 3 is a schematic view of a low-density winding layer structure in a thermal insulation container provided by the invention;

Fig. 4 is a schematic diagram of a composite gas-barrier film structure in a thermal insulation container provided by the invention.

Wherein, the vacuum insulation container is 10-vacuum insulation container, the liner is 11-and the dry fiber gradient winding layer is 12-and the gas barrier film is 13-composite;

111-liner opening, 112-cylindrical section, 113-end socket section, 121-tightly wound inner layer, 122-low-density winding layer, 123-tightly wound outer layer, 124-circumferential winding layer, 125-spiral winding layer, 131-innermost film, 132-vacuum aluminized film and 133-anti-collision layer.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present invention. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

As known to those skilled in the art, fiber coverage can be understood as the ratio of the area covered by fibers to the surface area of the wound body where the fibers are laid down on the surface of the wound body; the fiber volume content is the ratio of the fiber volume to the three-dimensional volume within a certain three-dimensional volume range. Because the fiber shape is circular, although 100% is laid flat on the surface of the winding body, the volume content is not 100%. In the present invention, the tightly wound layer and the low density wound layer are directly distinguished by the difference in the fiber volume content.

Fig. 1 schematically shows the structure of a thermal insulation container according to an embodiment of the present invention. The invention provides a vacuum heat-insulating container 10 integrating bearing and heat insulation, wherein the vacuum heat-insulating container 10 is of a multi-layer structure and comprises an inner container 11, a dry fiber gradient winding layer 12 and a composite air-insulating film 13, wherein the inner container 11 and the composite air-insulating film 13 are connected through a container opening to form a vacuum cavity, and the dry fiber gradient winding layer 12 is positioned in the vacuum cavity to play a supporting role.

The dry fiber gradient winding layer 12 is a dry fiber winding multilayer structure and comprises a tightly wound layer 121 tightly wound on the outer surface of the inner container and a tightly wound layer 123 tightly wound on the inner surface of the composite gas-barrier film 13, a low-density winding layer 122 is arranged between the tightly wound layer 121 and the tightly wound layer 123, the low-density winding layer 122 is formed by sparse winding of fibers, a plurality of cavities are formed, and the density of the vacuum heat-insulating container can be reduced.

The shape of the inner container 11 can be round or square, and the material can be high polymer materials such as polybutene, high density polyethylene, etc., or stainless steel, enamel, etc. Preferably, the liner is circular, the structure mainly comprises a liner opening 111, a cylindrical section 112 and a seal head section 113, the material is preferably polybutene or HDPE material, and the liner is formed by blow molding, and the blow molding process can adopt extrusion blow molding, injection blow molding and other modes. The volume of the inner container 11 is preferably (40+/-4) L; the thickness of the liner opening 111 is 3 plus or minus 0.2 mm, and the thickness of the cylindrical section 112 is 2 plus or minus 0.2 mm; the thickness (3+/-0.2) mm of the end socket section 113. According to the size requirement of the container liner, corresponding aluminum or steel mould is designed and prepared, and according to HDPE granules (75-85%): plastic plasticizer (5-15%): antioxidant (1%): hardness control agent (1%): pigment (5-15%) is proportioned, stirred and dried for 8 hours in a stirrer at 90 ℃, heated and melted by an extruder through a hopper of a blow molding machine, the extrusion temperature is set to be 190-250 ℃, the extrusion speed is controlled to be 10-25 m/min, the pigment is blown into a cavity of a mold through an injection molding head, the temperature of a die head is set to be 160-190 ℃, the blowing temperature is controlled to be 60-80 ℃, and then the pigment is taken out after cooling molding.

As shown in fig. 1 and 2, the dry fiber gradient winding layer 12 is coaxial with the liner 11, and the dry fiber gradient winding layer 12 is made of one or more mixed fibers such as glass fiber, basalt fiber, carbon fiber, aramid fiber and the like. Including a tightly wound inner layer 121, a low density wound layer 122, and a tightly wound outer layer 123; in this embodiment, the tightly wound inner layer 121 is made of T700 carbon fiber with a density of 12K; designing 1 winding unit, comprising two layers of 90-degree circumferential winding layers 124, one layer of 55-degree spiral winding layers 125 and one layer of 40-degree spiral winding layers 125; yarn width 15mm; the maximum yarn outlet speed is 30m/min; adopting a winding track of a geodesic wire and a fixed-length fiber enveloping form; winding fiber coverage rate 100%; the thickness of the cylindrical section 112 is 0.6 + -0.1 mm. The fiber volume content was 70%.

When in winding, the technical personnel can solve the problems of no resin infiltration, bonding, stress transfer effect on the fibers, and factors such as fiber compression, accumulation, friction, contact and the like, and the yarn slipping problem in the dry fiber winding forming process by controlling parameters such as winding tension, yarn bundle width, pole hole diameter, core mold size and the like according to the actual conditions that the thicknesses of fiber layers are increased layer by layer in the winding process, the thicknesses of reinforcing layers at the positions where fibers are overlapped and compressed are different, and the thickness of a tightly wound inner layer can be designed according to the conditions that the container bears internal pressure.

In this embodiment, as shown in fig. 1 and 3, the low-density winding layer 122 is made of glass fiber with a density of 2400 Tex; 7 winding units are designed, wherein each winding unit comprises two layers of 90-degree circumferential winding layers 124, one layer of 28-degree spiral winding layers 125 and one layer of 33-degree spiral winding layers 125; yarn width 15mm; the maximum yarn outlet speed is 50m/min; adopting a winding track of a geodesic wire and a fixed-length fiber enveloping form; winding fiber coverage rate 7%; the thickness of the cylindrical section 112 (6.8.+ -. 0.1) mm. The fiber volume content was 5%.

The tightly wound outer layer 123 is the same material and winding pattern as the tightly wound inner layer 121. Winding fiber coverage rate 100%; the thickness of the cylindrical section 112 is 0.6 + -0.1 mm. In this example, the dry fiber bulk fiber volume content was 15%.

The composite gas barrier film 13 is composed of a multi-layer film material, and may be a metal-based film material or a polyester film material. Preferably, the composite gas-barrier film is formed by compounding three or more films, and the total thickness is 0.5mm. As shown in fig. 4, the innermost film 131 is made of polybutene or HDPE material which is identical to the material of the liner, and is connected to the liner at the liner opening by hot melt connection, and has a thickness of 0.2mm. An aluminum film 132 was plated on the outside of the film 131 by a vacuum aluminum plating process to a thickness of 0.04mm. The outside is compounded with a continuous fiber reinforced thermoplastic composite anti-collision layer 133 with a thickness of 0.6mm.

The maximum bearable internal pressure of the container prepared by the embodiment is 3.9MPa, and the heat conductivity coefficient can reach 0.002-0.005W/mK. Taking a 40L water heater as an example, under the condition of internal pressure of 1.3MPa, the deformation is about 2.8mm, and compared with a water heater with a resin-based winding bearing layer and a polyurethane foam heat-insulating layer, the overall thickness of the water heater is reduced from 45mm to about 10.8mm, the space volume of the whole water heater is reduced by about 35%, and the mass is reduced by about 9.2%.

Claims (10)

1. The bearing-heat preservation integrated vacuum heat preservation container is characterized by comprising an inner container, a dry fiber gradient winding layer and a composite gas-barrier film, wherein the inner container and the composite gas-barrier film are connected through a container opening in an adhesive manner to form an intermediate vacuum cavity structure; the dry fiber gradient winding layer comprises a plurality of gradient layers, the material is dry fiber, the dry fiber gradient winding layer does not contain a resin matrix, the volume density of the fiber is in gradient change, and each gradient layer adopts a geodesic winding mode.

2. The vacuum heat-insulating container according to claim 1, wherein the liner structure of the heat-insulating container comprises a barrel body and an end socket, the barrel body is round or square, the liner is made of high polymer materials through a blow molding process or is made of stainless steel or enamel materials, and the high polymer materials are made of polyolefin materials.

3. The vacuum insulation container according to claim 1, wherein the dry fiber gradient winding layer is wrapped on the outer side of the inner container and comprises a tightly wound inner layer, a low density winding layer and a tightly wound outer layer; the coverage rate of the fiber of the tightly wound inner layer and the tightly wound outer layer is 90% -100%, and the coverage rate of the fiber of the low-density winding layer is 10% -20%; the volume content of the fiber of the tightly wound inner layer and the tightly wound outer layer is 50-80%, and the volume content of the fiber of the low-density winding layer is within 20%; the dry fiber adopts inorganic fiber or organic fiber, the inorganic fiber is selected from glass fiber, carbon fiber and basalt fiber, the organic fiber is selected from aramid fiber and ultra-high molecular weight polyethylene fiber, and the volume content of the whole fiber is 8-20%.

4. A vacuum insulation container according to claim 3, wherein the volume content of the fiber of the tightly wound inner layer and the tightly wound outer layer is 70% -80%, the tightly wound inner layer is connected with the outer surface of the inner container, the tightly wound outer layer is connected with the inner surface of the composite gas-barrier film, and the thickness of the tightly wound inner layer and the tightly wound outer layer is in the range of 0.2-5 mm.

5. A vacuum insulation container according to claim 3 wherein the tightly wound inner layer and the tightly wound outer layer are wound in a line type selected from one or a mixed winding of hoop winding, spiral winding, and the hoop winding angle is selected from 80 ° to 90 ° and the spiral winding angle is selected from 0 ° to 65 °.

6. A vacuum insulated container according to claim 3, wherein the low density wound layer has a fiber volume content of 5 to 15%.

7. The vacuum insulation container according to claim 6, wherein the low-density winding layer is provided on the outer side of the tightly wound inner layer, the number of yarn bundles is adjusted to 1/2 to 1/5 of the tightly wound inner layer when the low-density winding layer is wound, and the yarn width is designed to be 2 to 5 times of the tightly wound inner layer; the winding line type is selected from one or a mixed winding mode of circumferential winding and spiral winding, the circumferential winding angle is selected from 80-90 degrees, and the spiral winding angle is selected from 0-65 degrees.

8. A vacuum insulation container according to claim 3, wherein the composite gas barrier film is wrapped on the outer side of the tightly wound outer layer, and comprises a multi-layer film structure comprising a high polymer material inner film consistent with the inner container material, a vacuum aluminum plating film, and a fiber reinforced thermoplastic composite material layer.

9. The vacuum insulated container of claim 1, wherein the insulated container is a water heater, insulated storage tank, or food storage and transportation tank.

10. The preparation method of the bearing-heat preservation integrated vacuum heat preservation container is characterized by comprising a blowing process of an inner container, a winding process of a dry fiber gradient winding layer, a laying process of a composite gas-barrier film and a vacuumizing process; wherein,

The blow molding process of the liner comprises the following steps: the liner material is prepared by mixing polyolefin granules, plastic plasticizer, antioxidant, pigment=75-85% (5-15%), 1% (1%) (5-15%) in a proportion of 5-15 percent, stirring in a stirrer at 90-120 ℃ and drying for 4-12 hours, heating and melting in a blowing machine hopper through an extruder, setting the extrusion temperature to 190-250 ℃, controlling the extrusion speed to 10-25 m/min, blowing in a die cavity through an injection head, setting the die head temperature to 160-190 ℃, controlling the blowing temperature to 60-80 ℃, cooling and molding, and taking out;

The winding process of the dry fiber gradient winding layer comprises the following steps: the dry fiber is wound in a single or mixed mode in 0-65 DEG spiral winding and 80-90 DEG circumferential winding, the end covers at the two ends are respectively wound in a stepless hole winding mode and a polar hole winding mode, the yarn width is controlled to be 3-40 mm, the number of winding layers of each winding angle is designed according to the requirements of a container, the winding tension is controlled to be 5-8% of the breaking force of the fiber bundle, and the yarn outlet speed is controlled to be 10-50 m/min.