阅读说明：本技术 一种厚壁碳纤维复合材料的回收方法 (Recovery method of thick-wall carbon fiber composite material ) 是由 杨斌 翁亚楠 李鑫 倪静娴 翟律军 陈俐 韩建国 于 2020-05-07 设计创作，主要内容包括：本发明涉及一种厚壁碳纤维复合材料的回收方法,包括以下步骤：S1、将厚壁碳纤维复合材料在热解设备中加热至热解温度,且加热时为无氧环境加热,厚壁碳纤维复合材料在厚度方向上为层状结构；S2、加热至热解温度后,保持温度不变并通入氧气进行热解分层,氧气含量为1～8％,热解分层时间不少于5min；S3、热解分层结束后冷却至室温,取出出现分层的碳纤维复合材料；S4、将分层的碳纤维复合材料沿厚度方向进行剥离；S4、将剥离好的碳纤维复合材料加热至300～900℃,保持10～120min,得到软质再生碳纤维复合材料。该方法得到的软质再生碳纤维性能均匀性好、力学强度保持率高、品质可控性强、经济价值高,并且无需破碎操作和装备,降低回收成本。(The invention relates to a method for recycling a thick-wall carbon fiber composite material, which comprises the following steps: s1, heating the thick-wall carbon fiber composite material to a pyrolysis temperature in pyrolysis equipment, wherein the heating is carried out in an oxygen-free environment, and the thick-wall carbon fiber composite material is of a laminated structure in the thickness direction; s2, heating to a pyrolysis temperature, keeping the temperature unchanged, and introducing oxygen for pyrolysis layering, wherein the oxygen content is 1-8%, and the pyrolysis layering time is not less than 5 min; s3, cooling to room temperature after pyrolysis layering is finished, and taking out the layered carbon fiber composite material; s4, peeling the layered carbon fiber composite material along the thickness direction; s4, heating the stripped carbon fiber composite material to 300-900 ℃, and keeping for 10-120 min to obtain the soft regenerated carbon fiber composite material. The soft regenerated carbon fiber obtained by the method has good performance uniformity, high mechanical strength retention rate, strong quality controllability and high economic value, does not need crushing operation and equipment, and reduces the recovery cost.)

1. A method for recycling thick-wall carbon fiber composite material is characterized by comprising the following steps:

s1, heating the thick-wall carbon fiber composite material to a pyrolysis temperature in pyrolysis equipment in a layered manner, wherein the heating is carried out in an oxygen-free environment, and the thick-wall carbon fiber composite material is of a layered structure in the thickness direction;

s2, carrying out pyrolysis layering, heating to a pyrolysis temperature, keeping the temperature unchanged, and introducing oxygen to carry out pyrolysis layering, wherein the oxygen content is 1-8%, and the pyrolysis layering time is not less than 5 min;

s3, cooling after pyrolysis layering is finished, and taking out the layered carbon fiber composite material after cooling;

s4, stripping, namely stripping the layered carbon fiber composite material in the thickness direction;

s4, regenerating, namely heating the stripped carbon fiber composite material to 300-900 ℃, and keeping for 10-120 min to obtain the soft regenerated carbon fiber composite material.

2. The recycling method of thick-walled carbon fiber composite material as claimed in claim 1, wherein the pyrolysis temperature is 300-900 ℃.

3. The method of claim 1, wherein the oxygen-free environment is a nitrogen, steam, superheated steam or helium atmosphere.

4. The method for recycling a thick-walled carbon fiber composite material as claimed in claim 1, wherein the peeled thickness of the carbon fiber composite material is 0.1 to 10 mm.

5. The recycling method of thick-walled carbon fiber composite material as claimed in claim 1, wherein the pyrolysis delamination time is 5-120 min.

6. A method as claimed in claim 1, wherein the carbon fiber composite material has a thickness of 3-N mm, where N is a function of the free space height H in the pyrolysis apparatus, and H is 4N when H is 120mm or less; when H is 120-700 mm, H is 5N; when H is 700-2500 mm, H is 7N.

7. The recycling method of thick-walled carbon fiber composite material as claimed in claim 1, wherein the thick-walled carbon fiber composite material is manufactured by any one of autoclave molding, RTM molding, winding molding and wet compression molding.

8. The method of claim 1, wherein the matrix resin of the thick-walled carbon fiber composite is a thermosetting resin or a thermoplastic resin;

the thermosetting resin comprises one or more of epoxy resin, unsaturated polyester resin, polyurethane resin, phenolic resin, polyimide resin, urea-formaldehyde resin, melamine-formaldehyde resin, organic silicon resin and furan resin;

the thermoplastic resin includes one or more of polyphenylene sulfide, polyether ether ketone, polysulfone, thermoplastic polyimide, polyarylate, liquid crystal polymer, polytetrafluoroethylene, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, polyamide, polyphenylene oxide, polyethylene, polypropylene, polyvinyl chloride, polystyrene, and acrylonitrile-butadiene-styrene copolymer.

9. The method of claim 1, wherein the carbon fiber in the thick-walled carbon fiber composite is one or more of polyacrylonitrile-based carbon fiber, pitch-based carbon fiber or viscose-based carbon fiber.

10. The method of claim 1, wherein the carbon fibers in the thick-walled carbon fiber composite are in the form of continuous fibers and/or discontinuous fibers.

Technical Field

The invention relates to a method for recycling a carbon fiber composite material, in particular to a method for recycling a thick-wall carbon fiber composite material.

Background

Carbon fiber reinforced resin composite materials have excellent properties such as high specific strength, high specific modulus, heat resistance and corrosion resistance, and are therefore widely used in the aerospace field, sports and leisure fields such as golf clubs and tennis rackets, and industrial application fields such as automobiles, wind power generation, pressure vessels, electronic appliances, and medical devices. Leftover materials and defective products generated in the production process of the carbon fiber reinforced resin matrix composite material and structural parts damaged in the using process contain a large amount of expensive carbon fibers, and the recycling and the reutilization of the carbon fiber reinforced resin matrix composite material become a key problem which needs to be solved urgently.

Disclosure of Invention

In order to solve the problems, the invention provides a method for recycling a thick-wall carbon fiber composite material, which has the advantages of good performance uniformity, high strength retention rate, no need of crushing operation and low recycling cost, and the specific technical scheme is as follows:

a method for recycling thick-wall carbon fiber composite material comprises the following steps:

s1, heating the thick-wall carbon fiber composite material to a pyrolysis temperature in pyrolysis equipment in a layered manner, wherein the heating is carried out in an oxygen-free environment, and the thick-wall carbon fiber composite material is of a layered structure in the thickness direction;

s2, carrying out pyrolysis layering, heating to a pyrolysis temperature, keeping the temperature unchanged, and introducing oxygen to carry out pyrolysis layering, wherein the oxygen content is 1-8%, and the pyrolysis layering time is not less than 5 min;

s3, cooling after pyrolysis layering is finished, and taking out the layered carbon fiber composite material after cooling;

s4, stripping, namely stripping the layered carbon fiber composite material in the thickness direction;

s4, regenerating, namely heating the stripped carbon fiber composite material to 300-900 ℃, and keeping for 10-120 min to obtain the soft regenerated carbon fiber composite material.

Preferably, the pyrolysis temperature is 300-900 ℃.

Preferably, the oxygen-free environment is a nitrogen, water vapor, superheated water vapor or helium gas atmosphere environment.

Preferably, the stripping thickness of the carbon fiber composite material during stripping is 0.1-10 mm.

Preferably, the thickness of the carbon fiber composite material is 3-N mm, wherein N is a function of the height H of free space in the pyrolysis equipment, and when H is less than 120mm, H is 4N; when H is 120-700 mm, H is 5N; when H is 700-2500 mm, H is 7N.

Preferably, the pyrolysis layering time is 5-120 min.

Preferably, the thick-wall carbon fiber composite material is manufactured by any one of autoclave molding, RTM molding, winding molding and wet compression molding.

Preferably, the matrix resin of the thick-walled carbon fiber composite material is a thermosetting resin or a thermoplastic resin;

the thermosetting resin comprises epoxy resin, unsaturated polyester resin, polyurethane resin, phenolic resin, polyimide resin, urea-formaldehyde resin, melamine-formaldehyde resin, organic silicon resin and furan resin;

the thermoplastic resin includes polyphenylene sulfide, polyether ether ketone, polysulfone, thermoplastic polyimide, polyarylate, liquid crystal polymer, polytetrafluoroethylene, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, polyamide, polyphenylene oxide, polyethylene, polypropylene, polyvinyl chloride, polystyrene, and acrylonitrile-butadiene-styrene copolymer.

Preferably, the carbon fiber in the thick-wall carbon fiber composite material is one or more of polyacrylonitrile-based carbon fiber, pitch-based carbon fiber or viscose-based carbon fiber.

Preferably, the carbon fibers in the thick-walled carbon fiber composite material are in the form of continuous fibers and/or discontinuous fibers.

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

the invention provides a method for recovering thick-wall carbon fiber composite material

The consistency of the performance and the mechanical property retention rate of the soft regenerated carbon fiber extracted from the thick-wall carbon fiber composite waste are obviously improved, and the quality controllability and the yield in production are improved, so that the economic benefit of recycling enterprises is improved;

secondly, crushing operation and special crushing equipment are not needed, so that the operation cost and the equipment cost are reduced, and the recovery cost is reduced;

the surface of the obtained soft regenerated carbon fiber has no carbon deposit residue, which is beneficial to surface sizing modification in subsequent recycling and is also very suitable for being directly processed into recycled products with excellent quality such as carbon paper, non-woven felt or spinning yarn;

and fourthly, the range of the types of the discarded carbon fiber composite materials which can be recycled is greatly widened, the recycling of the newspaper waste products of the all-carbon fiber composite material industry is facilitated, and the construction of the recyclable industry is promoted.

Drawings

FIG. 1 is a scanning electron micrograph of a regenerated carbon fiber obtained in example 1 of the present invention;

FIG. 2 is a scanning electron micrograph of the regenerated carbon fiber obtained in comparative example 2.

Detailed Description

The invention will now be further described with reference to the accompanying drawings.

A method for recycling thick-wall carbon fiber composite material comprises the following steps:

s1, heating in a layered mode, namely heating the thick-wall carbon fiber composite material in pyrolysis equipment to a pyrolysis temperature of 300-900 ℃, wherein the heating is carried out in an oxygen-free environment, and the thick-wall carbon fiber composite material is of a layered structure in the thickness direction;

s2, carrying out pyrolysis layering, heating to a pyrolysis temperature, keeping the temperature unchanged, and introducing oxygen for pyrolysis layering, wherein the oxygen content is 1-8%, and the pyrolysis layering time is 5-120 min;

s3, cooling after pyrolysis layering is finished, and taking out the layered carbon fiber composite material after cooling;

s4, stripping, namely stripping the layered carbon fiber composite material in the thickness direction, wherein the stripping thickness of the carbon fiber composite material is 0.1-10 mm;

s4, regenerating, namely heating the stripped carbon fiber composite material to 300-900 ℃, and keeping for 10-120 min to obtain the soft regenerated carbon fiber composite material.

The essence of the method lies in that the characteristic that the carbon fiber reinforced resin composite material is easy to peel after being fully pyrolyzed and the thick-wall carbon fiber reinforced resin composite material is layered in the thickness direction is utilized, and the difference of internal and external reactions is eliminated by changing the thickness into thin, so that the consistency of the performance of the soft regenerated carbon fiber is greatly improved. The soft regenerated carbon fiber has good performance uniformity and high strength retention rate, and compared with the prior art, the problem of large difference between the performance of the outer layer carbon fiber and the performance of the inner layer carbon fiber when the waste of the thick-wall carbon fiber composite material is recycled is solved.