CN111171553A

CN111171553A - Electromagnetic wave shielding composite material

Info

Publication number: CN111171553A
Application number: CN201811348729.2A
Authority: CN
Inventors: 柴浣兰; 周锦东
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-11-13
Filing date: 2018-11-13
Publication date: 2020-05-19

Abstract

An electromagnetic wave shielding composite material comprises polymer waste and conductive carbon black. The polymer waste comprises at least one of waste polylactic acid products and waste polyurethane products. The ratio of the total weight of the polymer waste to the weight of the conductive carbon black is more than 0 and less than 30. By adding the conductive carbon black, the polymer waste is endowed with new value, the utilization rate of the polymer waste is improved, the utilization period is prolonged, and the cost for treating the polymer waste and the harm and load to the environment are reduced.

Description

Electromagnetic wave shielding composite material

Technical Field

The present invention relates to an electromagnetic shielding composite material, and more particularly to an electromagnetic shielding composite material containing polymer waste and conductive carbon black.

Background

The polymer materials (such as plastics or rubber and the like) bring convenience to life of people and improve the life quality of people, and meanwhile, a large amount of waste polymer materials after being used are increased day by day and cause considerable negative effects on the environment. The waste polymer is difficult to naturally decompose, resulting in increase of solid waste, and the incineration method also causes air pollution, and even part of the waste polymer, such as polyvinyl chloride, releases harmful substances during the incineration process, so that the use of polymer is reduced or the development of degradable polymer is actively pursued, and the recycling of the waste polymer is a problem that can be further broken through by those skilled in the art.

It is worth noting that according to the statistics of the resource recovery management fund management committee of the taiwan area, the recycling amount of the waste plastic containers in taiwan area of china in 2012 is about 189,254 metric tons, wherein the recycling amount of the waste polyethylene/polypropylene is about 82,332 tons, and the recycling amount of the polyethylene terephthalate (polyethylene terephthalate) is about 96,133 tons, which respectively account for 44% and 51% of the recycling amount of the waste plastic containers.

Furthermore, one of the current environmental policies in taiwan is to strongly promote the use of biodegradable plastics to replace part of the conventional plastics, wherein polylactic acid can be decomposed in nature. According to statistics that the usage amount of polylactic acid in taiwan area in China in 2008 is about 1,500 tons, and is increased to 1,600 tons in 2009, and about 134 tons of polylactic acid is totally recovered in taiwan area from 2010 to 2011, under the promotion of policy, the recovery amount of waste polylactic acid can be expected to increase year by year.

Based on the above, how to recycle the huge amount of waste plastic resources, improve recycling efficiency, and reduce environmental load has become an important environmental issue.

Disclosure of Invention

The invention aims to provide an electromagnetic wave shielding composite material.

The electromagnetic wave shielding composite material of the present invention comprises polymer waste and conductive carbon black. The polymer waste comprises at least one of waste polylactic acid products and waste polyurethane products. The ratio of the total weight of the polymer waste to the weight of the conductive carbon black is more than 0 and less than 30.

The invention has the beneficial effects that: by adding the conductive carbon black, the polymer waste is endowed with new value, the utilization rate of the polymer waste is improved, the utilization period is prolonged, and the cost for treating the polymer waste and the harm and load to the environment are reduced.

Drawings

Is free of

Detailed Description

The present invention will be described in detail below.

< Polymer waste >

Such as, but not limited to, recycled pet bottles or recycled cake boxes. Such waste polyurethane products are, for example, but not limited to, polyurethane leftovers and the like remaining during the production of conventional materials for elastic fibers, synthetic leather resins and the like in the textile industry. The waste polyurethane product is formed from components comprising polyester-based thermoplastic polyurethane. The polymer waste also contains waste polyethylene terephthalate products. Such as, but not limited to, recycled beverage bottles and the like.

< conductive carbon Black >

The conductive carbon black is commercially available conductive carbon black or is prepared by carbonizing polylactic acid. The conductive carbon black has a particle size in the range of less than 100 nm. In this example, the conductive carbon black had a particle diameter of 30nm and a BET specific surface area of 1,000m²(ii)/g, and an oil absorption of carbon black (DBP) of 420g/100 g.

Since science and technology are changing day by day, electronic products are continuously being brought forward, human life has been disconnected from using electronic products, human body is exposed to electromagnetic waves of various frequencies at any time, which is harmful to human body, and electromagnetic waves generated by electronic products can interfere with the products. The electromagnetic wave shielding composite material is applied to the electronic products, so that the harm to human bodies and the interference to the products can be reduced, the utilization rate of polymer wastes can be improved, the cost for treating the polymer wastes and the harm and the load to the environment can be reduced, and the electromagnetic wave shielding composite material has better industrial utilization and is also an important and valuable development.

It should be noted that the electromagnetic wave shielding composite material of the present invention can be applied to the casings of mobile phones with different frequencies, the casings of wireless sharers, the casings of microwave ovens, the casings of VHF wireless microphones, the casings of wireless phones or computer casings, etc.

The invention will be further described in the following examples, but it should be understood that these examples are for illustrative purposes only and should not be construed as limiting the practice of the invention.

< example 1>

Waste cake boxes (main raw material: polylactic acid) and leftovers (main raw material: polyester type thermoplastic polyurethane) remaining in the processes of recycling elastic fibers and producing synthetic leather and resin textiles were cleaned, cut into a size of 1cm × 0.5cm, and mixed, followed by drying in a vacuum oven at 40 ℃ for 24 hours to obtain dry pieces. 40 g of dry fragments and 4 g of conductive carbon black (orion, trademark) are placed in a plastograph, heated at 310 ℃ and the rotating speed is 60rpm, so that the dry fragments and the conductive carbon black are completely melted and mixed to be in a uniform state, and then cooled, thus obtaining the electromagnetic wave shielding composite material.

< examples 2 to 5>

Examples 2 to 5 electromagnetic wave shielding composites were prepared in the same procedure as in example 1, except that: the amount of conductive carbon black used was varied as shown in table 1.

< example 6>

Waste recovered elastic fibers and leftover materials (main raw material: polyester thermoplastic polyurethane) remained in the production process of synthetic leather resin textiles are cleaned and cut into the size of 1cm multiplied by 0.5cm, and then the waste recovered elastic fibers and leftover materials are dried for 24 hours in a vacuum oven at the temperature of 40 ℃ to obtain dry fragments. 40 g of dry fragments and 12 g of conductive carbon black (orion, trademark) are placed in a plastograph, heated at 310 ℃ and the rotating speed is 60rpm to be completely melted and mixed to be in a uniform state, and then cooled to obtain the electromagnetic wave shielding composite material.

< application example 1>

The electromagnetic wave shielding composite material of example 1 was placed in a hot press (brand: RISEN INSTRUMENTS; model: HAS-100TON type) at 275 ℃ for 5 minutes, followed by sequentially heating at 50kg/cm²、80kg/cm²、100kg/cm²And 200kg/cm²And the hot pressing is performed for 5 minutes, 3 minutes, 2 minutes and 1 minute in this order to perform the molding process. Then, the sample to be measured (length: 110 mm; thickness: 5mm) was obtained by cooling for 10 minutes.

< application examples 2 to 6 >)

Application examples 2 to 6 samples 2 to 6 to be tested were prepared in the same procedure as in application example 1, except that: the source of the electromagnetic shielding composite is shown in table 1.

< comparative application example 1>

Waste cake boxes (main raw material: polylactic acid) and leftovers (main raw material: polyester type thermoplastic polyurethane) remaining in the processes of recycling elastic fibers and producing synthetic leather and resin textiles were cleaned, cut into a size of 1cm × 0.5cm, and mixed, followed by drying in a vacuum oven at 40 ℃ for 24 hours to obtain dry pieces. 40 g of the dried chips were placed in a plastograph and heated at 310 ℃ and 60rpm to completely melt them, and then cooled to obtain a polymer material. The polymer material was placed in a hot press (brand: RISEN INSTRUMENTS; model: HAS-100TON type) at 275 ℃ for 5 minutes, followed by 50kg/cm in this order²、80kg/cm²、100kg/cm²And 200kg/cm²And the hot pressing is performed for 5 minutes, 3 minutes, 2 minutes and 1 minute in this order to perform the molding process. Then, the sample to be measured (length: 110 mm; thickness: 5mm) was obtained by cooling for 10 minutes.

< comparative application example 2>

Waste recovered elastic fiber and leftover material (polyester type thermoplastic polyurethane as main material) left in the production process of synthetic leather and resin textile are cleaned and cut into 1cm.times.0.5 cm, followed by drying in a vacuum oven at 40 ℃ for 24 hours to obtain dried pieces. 40 g of the dried chips were placed in a plastograph and heated at 310 ℃ and 60rpm to completely melt them, and then cooled to obtain a polymer material. The polymer material was placed in a hot press (brand: RISENINSTRUMENTS; model: HAS-100TON type) at 275 ℃ for 5 minutes, followed by 50kg/cm in this order²、80kg/cm²、100kg/cm²And 200kg/cm²And the hot pressing is performed for 5 minutes, 3 minutes, 2 minutes and 1 minute in this order to perform the molding process. Then, the sample to be measured (length: 110 mm; thickness: 5mm) was obtained by cooling for 10 minutes.

< evaluation items >

Electromagnetic shielding effect measurement: application examples 1 to 6 and comparative application examples 1 to 2 were analyzed using a vector network analyzer (brand: Agilent; model: 8722 ES). The analysis method comprises the following steps: the test frequency was 50MHz to 1500MHz and the signal source power was 0dB and was performed according to ASTM-D4935-87.

TABLE 1

In summary, the addition of the conductive carbon black can provide new value to the polymer waste, improve the utilization rate of the polymer waste, prolong the utilization period, and reduce the cost of polymer waste treatment and the environmental damage and load, thereby achieving the purpose of the present invention.

Claims

1. An electromagnetic wave shielding composite material, comprising: polymer waste including at least one of waste polylactic acid products and waste polyurethane products;

and conductive carbon black; wherein the ratio of the total weight of the polymer waste to the weight of the conductive carbon black is greater than 0 and less than 30.

2. The electromagnetic wave shielding composite material according to claim 1, wherein: the waste polyurethane product is formed from components comprising polyester-based thermoplastic polyurethane.