阅读说明：本技术 一种木棉纤维真空绝热板芯材及其制备方法与应用 (Kapok fiber vacuum insulation panel core material and preparation method and application thereof ) 是由 徐峻 孙乾乾 李军 王斌 陈克复 于 2021-08-06 设计创作，主要内容包括：本发明涉及新型生物基保温材料领域,公布了一种木棉纤维真空绝热板芯材制备方法,所述芯材由木棉纤维片层叠而成。具体制备步骤如下：将原生木棉纤维粉碎,然后对粉碎后的木棉纤维进行预处理；将预处理后的干燥木棉纤维在水中分散,通过抄造、抽滤等方法制成纤维片,再次干燥后,得到木棉纤维基真空绝热板芯材。本发明所用原料为天然植物纤维,绿色环保,自然条件下可生物降解,生产过程对人体无害,同时还可以增加木棉纤维的高值化应用途径,由该芯材制备的真空绝热板密度小、厚度薄、导热系数低。(The invention relates to the field of novel bio-based heat insulation materials, and discloses a preparation method of a kapok fiber vacuum heat insulation panel core material. The preparation method comprises the following specific steps: pulverizing the original kapok fiber, and then pretreating the pulverized kapok fiber; dispersing the pretreated dry kapok fiber in water, making into fiber sheets by methods of papermaking, suction filtration and the like, and drying again to obtain the kapok fiber-based vacuum insulation panel core material. The raw materials used by the invention are natural plant fibers, are green and environment-friendly, can be biologically degraded under natural conditions, are harmless to human bodies in the production process, and can increase the high-value application approach of the kapok fibers.)

1. A preparation method of a kapok fiber vacuum insulation panel core material is characterized by comprising the following steps:

(1) pretreatment: treating the raw kapok fiber by using a steeping liquor;

(2) foaming: drying the pretreated fiber raw material, fully dispersing the dried fiber raw material in water to obtain fiber slurry, and mixing the fiber slurry with a PVA solution foaming agent for foaming;

(3) molding: and (3) making the foamed fiber slurry into a shape by a net, defoaming to prepare fiber sheets, drying, and stacking to obtain the kapok fiber vacuum insulation panel core material.

2. The method of claim 1, wherein: the mass concentration of the PVA solution in the step (2) is 0-1.0%, but not 0.

3. The method of claim 1, wherein: the mass concentration of the fiber slurry in the step (2) is 0.1-3%.

4. The method of claim 1, wherein: the volume ratio of the PVA solution to the fiber slurry in the step (2) is 1:1-1: 9.

5. The method of claim 1, wherein: in the step (1), the impregnation liquid is alkaline aqueous solution; the mass concentration of the impregnation liquid is 0.1-1.0%.

6. The method of claim 1, wherein: the step (1) of using the steeping liquor for treatment specifically comprises the step of soaking the raw kapok fibers in the steeping liquor for 0.5-72 h.

7. The method of claim 1, wherein: the drying temperature in the step (2) is 80-120 ℃, and the drying time is 0.5-8 h;

and (3) defoaming in a vacuum defoaming mode, wherein the vacuum degree is not higher than 1KPa, and the time is 2-5 min.

8. The method of claim 1, wherein:

before treatment in an impregnation liquid, pulverizing the raw kapok fiber;

the impregnation liquid in the step (1) is at least one of potassium hydroxide and sodium hydroxide.

9. A kapok fiber vacuum insulation panel core material prepared according to the method of any one of claims 1 to 8.

10. Use of a kapok fiber vacuum insulation panel core material according to claim 9 in the field of insulation.

Technical Field

The invention relates to the field of novel bio-based heat insulation materials, in particular to a kapok fiber vacuum heat insulation panel core material and a preparation method and application thereof.

Background

Along with the rapid growth of social economy, people seek higher and higher comfort level of living environment, the energy consumption of China in the aspects of heating and refrigeration is increased year by year, in addition, the requirements on the aspects of food preservation, cold chain transportation and the like are higher and higher due to the rapid development of industries such as electronic commerce, express delivery, takeaway and the like, and the demand on high-performance heat-insulating and energy-saving materials is very urgent.

The Vacuum Insulation Panel (VIP) is mainly composed of a core material, a getter and a barrier film, is a novel Insulation material with ultralow heat conductivity coefficient, has the Insulation effect which can reach 3-8 times that of the traditional Insulation material compared with the traditional Insulation material, and can save a large amount of space in the using process. At present, core materials applied to vacuum insulation panels in a large scale mainly comprise glass fibers, aerogel, silicon dioxide, polyurethane foam and the like, but the core materials have the defects of severe production environment, harm to human health, high production cost, environmental friendliness and the like. In recent years, many researchers are dedicated to searching a green, healthy and renewable biomass material with a good heat preservation effect.

The patent with the authorization number of CN 108869951B discloses a preparation method of a low-density wood fiber vacuum insulation board, which is prepared by taking wood fibers as core materials and adopting a hot-press forming mode, and because no adhesive is used, the strength of the core materials is poor, and collapse is easy to occur in the process of packaging and transferring.

The patent with the authorization number of CN 107606396B discloses a vacuum insulation panel, which is prepared by mixing bamboo fibers with a certain proportion of glass fibers and utilizing a wet papermaking forming process, wherein the bamboo fiber vacuum insulation panel has a good heat insulation performance, but more glass fibers still need to be added, and the density is higher.

Disclosure of Invention

The invention provides a preparation method of a kapok fiber vacuum insulation panel core material, which is mainly prepared by preparing a fiber sheet from kapok fibers in a foaming forming mode, drying and laminating.

The invention also aims to provide the kapok fiber vacuum insulation panel core material prepared by the method.

The invention further aims to provide application of the obtained kapok fiber vacuum insulation panel core material in the field of heat preservation.

The invention provides a preparation method of a kapok fiber vacuum insulation panel core material, which comprises the following steps:

(1) pretreatment: treating the raw kapok fiber by using a steeping liquor;

(2) foaming: drying the pretreated fiber raw material, fully dispersing the dried fiber raw material in water to obtain fiber slurry, and mixing the fiber slurry with a PVA solution for foaming;

(3) molding: and (3) making the foamed fiber slurry into a shape by a net, defoaming to prepare fiber sheets, drying, and stacking to obtain the kapok fiber vacuum insulation panel core material.

Preferably, in step (1), the raw kapok fiber is first crushed before being treated in the impregnation solution. More preferably, the length of the comminuted raw kapok fibers is <3mm, preferably 0.8-2 mm.

Preferably, the impregnation liquid in the step (1) is an alkaline aqueous solution, preferably at least one of potassium hydroxide, sodium hydroxide and the like, more preferably, the mass concentration of the impregnation liquid is 0.1-1.0%,

preferably, the treatment with the impregnation solution in the step (1) is to soak the raw kapok fiber in the impregnation solution for 0.5 to 72 hours; more preferably 4-24 h.

Preferably, the drying temperature in the step (2) is 80-120 ℃, and the drying time is 0.5-8 h.

Preferably, the mass concentration of the fiber slurry in the step (2) is 0.1-3%, and the mass concentration of the PVA solution is 0-1.0%, but not 0; the volume ratio of the PVA solution to the fiber slurry is 1:1-1: 9.

Preferably, the foaming manner in the step (2) is mechanical stirring, the rotating speed is 1600-2000r/min, and the time is 10-60 min.

Preferably, the defoaming mode in the step (3) is vacuum defoaming, the vacuum degree is not higher than 1KPa, and the time is 2-5 min.

A kapok fiber vacuum insulation panel core material is prepared by the method.

The kapok fiber vacuum insulation panel core material is applied to the field of heat preservation.

Compared with the existing vacuum insulation panel core material, the vacuum insulation panel core material prepared by using the kapok fiber as the raw material is green, environment-friendly and renewable, can be degraded by biomass under natural conditions, is harmless to human bodies in the production process, and the vacuum insulation panel prepared by using the kapok fiber has the advantages of low heat conductivity coefficient, thickness of 5-8mm and volume weight of 0.05-0.14g/cm³And has good application prospect in the field of heat preservation of vacuum heat insulation plates.

Drawings

FIG. 1 is a schematic structural view of a kapok fiber vacuum insulation panel core material; wherein, the wood cotton fiber sheet is 10-wood cotton fiber sheet, and the single wood cotton fiber is 20-single wood cotton fiber;

Detailed Description

1) The raw kapok fiber is firstly crushed by a crusher, and the raw material with the fiber length of 0.8-2mm is the most preferable.

2) Dipping the crushed fiber raw material for 0.5 to 72 hours by using potassium hydroxide or other alkaline aqueous solution with the mass concentration of 0.1 to 1.0 percent;

3) putting the pretreated kapok fiber into a drying oven, and drying at 80-120 ℃ for 0.5-8 h;

4) fully dispersing the dried fiber raw material in water, pouring the obtained fiber slurry with the fiber concentration of 0.1-3% into a PVA aqueous solution with the concentration of 0-1.0 wt% for foaming, wherein the volume ratio of the PVA solution to the fiber slurry is 1:1-1:9, the foaming mode is mechanical stirring, the rotating speed is 1600-2000r/min, and the time is 10-60 min;

5) and (3) screening the fully foamed foam slurry, making paper, molding, defoaming in vacuum at a vacuum degree of not higher than 1KPa for 2-5min to prepare fiber sheets, drying at 105-180 ℃ for 0.5-24h, and stacking the layers after drying to obtain the vacuum insulation panel core material.

The invention will be further described with reference to the following examples for better understanding of the invention, but the scope of the invention as claimed is not limited to the scope shown in the examples.

Example 1:

(1) pulverizing the raw kapok fiber by a pulverizer, wherein the fiber length is between 0.8mm and 2 mm;

(2) dipping the dried kapok fiber raw material for 8 hours by using a sodium hydroxide aqueous solution with the mass concentration of 0.25%;

(3) putting the pretreated kapok fiber into a drying box, and drying for 6 hours at 105 ℃;

(4) weighing 2.0g of dried kapok fiber raw material, fully dispersing in 800ml of water, pouring into 200ml of PVA foaming liquid with the mass concentration of 0.25% for foaming, then screening and molding the fully foamed fiber material, preparing a fiber sheet with the sheet weight of about 1.5-1.7g through vacuum defoaming, drying at 168 ℃ for 1h, and stacking and placing 10 layers of the fiber sheet to obtain the vacuum insulation panel core material.

The thermal conductivity coefficient of the kapok fiber core material prepared by the embodiment is 0.041W (m.K)^-1The thermal conductivity coefficient of the kapok fiber vacuum insulation panel is 0.0069mW (m.K)^-1The thickness is 5.81mm and the volume weight is 0.115g/cm³。

Example 2:

(1) pulverizing the raw kapok fiber by a pulverizer, wherein the fiber length is between 0.8mm and 2 mm;

(2) dipping the dried kapok fiber raw material for 12 hours by using a potassium hydroxide aqueous solution with the mass concentration of 0.25%;

(3) washing the pretreated kapok fiber with water, putting the kapok fiber into a drying box, and drying for 4 hours at 125 ℃;

(4) weighing 1.0g of dried kapok fiber raw material, fully dispersing in 800ml of water, pouring into 200ml of PVA foaming liquid with the mass concentration of 0.5% for foaming, then screening and molding the fully foamed fiber material, preparing a fiber sheet with the sheet weight of about 0.7-0.9g through vacuum defoaming, drying at 155 ℃ for 5h, and stacking and placing the fiber sheets for 20 layers to obtain the vacuum insulation panel core material.

The kapok fiber core material prepared by the embodiment has the heat conductivity coefficient of 0.039W (m.K)^-1The thermal conductivity coefficient of the kapok fiber vacuum insulation panel is 0.0057mW (m.K)^-1The thickness was 6.52mm, and the bulk weight was 0.102g/cm 3.

Example 3:

(1) pulverizing the raw kapok fiber by a pulverizer, wherein the fiber length is between 0.8mm and 2 mm;

(2) dipping the dried kapok fiber raw material for 4 hours by using a sodium hydroxide aqueous solution with the mass concentration of 0.75%;

(3) putting the pretreated kapok fiber into a drying oven, and drying for 1h at 128 ℃;

(4) weighing 5.0g of dried kapok fiber raw material, fully dispersing in 400ml of water, pouring into 100ml of PVA foaming liquid with the mass concentration of 0.25% for foaming, then screening and molding the fully foamed fiber material, preparing a fiber sheet with the sheet weight of about 4.2-4.8g through vacuum defoaming, drying at 136 ℃ for 6h, and stacking the fiber sheets for 4 layers to obtain the vacuum insulation panel core material.

The kapok fiber core material prepared by the embodiment has the heat conductivity coefficient of 0.040W (m.K)^-1The thermal conductivity coefficient of the kapok fiber vacuum insulation panel is 0.0068mW (m.K)^-1The thickness is 7.8mm, and the volume weight is 0.086g/cm³。

Example 4:

(1) pulverizing the raw kapok fiber by a pulverizer, wherein the fiber length is between 0.8mm and 2 mm;

(2) dipping the dried kapok fiber raw material for 12 hours by using a sodium hydroxide aqueous solution with the mass concentration of 0.25%;

(3) putting the pretreated kapok fiber into a drying box, and drying for 5 hours at 105 ℃;

(4) weighing 5.0g of dried kapok fiber raw material, fully dispersing the raw material in 600ml of water, pouring the raw material into 100ml of PVA foaming liquid with the mass concentration of 0.5% for foaming, then screening and molding the fully foamed fiber material, preparing a fiber sheet with the sheet weight of about 4.2-4.8g through vacuum defoaming, drying the fiber sheet at 125 ℃ for 8 hours, and stacking 4 layers of fiber mats to obtain the vacuum insulation panel core material.

The kapok fiber core material prepared by the embodiment has the heat conductivity coefficient of 0.040W (m.K)^-1The thermal conductivity coefficient of the kapok fiber vacuum insulation panel is 0.0054mW (m.K)^-1The thickness is 6.2mm and the volume weight is 0.105g/cm³。

Example 5:

(1) pulverizing the raw kapok fiber by a pulverizer, wherein the fiber length is between 0.8mm and 2 mm;

(2) dipping the dried kapok fiber raw material for 24 hours by using a sodium hydroxide aqueous solution with the mass concentration of 0.25%;

(3) putting the pretreated kapok fiber into a drying oven, and drying for 3 hours at 125 ℃;

(4) weighing 2.0g of dried kapok fiber raw material, fully dispersing the dried kapok fiber raw material in 500ml of water, pouring the mixture into 50ml of PVA foaming liquid with the mass concentration of 0.25% for foaming, then screening and molding the fully foamed fiber material, preparing a fiber sheet with the sheet weight of about 1.5-1.7g through vacuum defoaming, drying the fiber sheet for 3 hours at 165 ℃, and stacking and placing 10 layers of the fiber sheet to obtain the vacuum insulation panel core material.

The kapok fiber core material prepared by the embodiment has the heat conductivity coefficient of 0.036W (m.K)^-1The thermal conductivity coefficient of the kapok fiber vacuum insulation panel is 0.0045mW (m.K)^-1The thickness is 5.2mm, and the volume weight is 0.119g/cm³. The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.