A kind of adhesive composition and solar battery back sheet

Abstract

The invention provides an adhesive composition and a solar cell rear panel. The adhesive composition is prepared from (methyl) acrylate polyhydric alcohols, organosilicone modified (methyl) acrylate polyhydric alcohols, an isocyanate compound, aids and a solvent, wherein the (methyl) acrylate polyhydric alcohols account for 15-30 percent; the organosilicone modified (methyl) acrylate polyhydric alcohols account for 1.5-6 percent; the content of the isocyanate compound is associated with the acrylate polyhydric alcohols; the ratio of OH groups in the acrylate polyhydric alcohols to NCO groups in the isocyanate compound (B) is 1:1-1.5; the content of an antioxidant is 0.2-2 percent; and the content of the solvent is 60-80 percent. According to the solar cell rear panel disclosed by the invention, the interlayer adhesive force can reach a level of over 6N / cm, the solar cell rear panel has excellent moisture-heat aging resistance and is resistant to double-85 aging for 3000 hours, the copolymer film and PE do not shrink, layer, blister relative to the intermediate insulating layer and a phenomenon that the adhesive layer is obviously sticky is avoided.

Description

technical field [0001] The invention relates to an adhesive composition and a solar cell backboard prepared therefrom, belonging to the technical field of solar cells. [0002] technical background [0003] Solar power generation uses the principle of photovoltaic effect of semiconductors such as silicon to directly convert solar visible light into electrical energy. If the silicon wafer is directly exposed to the air, it will be corroded by high and low temperature and water vapor. Its photoelectric conversion performance is easy to decay and loses its use value. Encapsulation is a key step in the production of solar cells. The encapsulation of solar cells is to "cover" the crystalline silicon wafer group, enclose the silicon wafer group, protect the upper layer of material glass, and use the vacuum lamination technology to protect the lower layer of material. glued together. [0004] Most of the solar battery backplane adopts a "sandwich" structure, that is, a three-laye...

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Problems solved by technology

[0004] Most of the solar battery backplane adopts a "sandwich" structure, that is, a three-layer film structure; the layers are bonded with an adhesive, and the adhesive plays a key role in the backplane. It directly affects the service life of the back sheet, and then affects the service life of the solar cell module. The middle layer of the solar cell back sheet is the support body PET, and the inner adhesive layer is generally EVA or polyolefin, which plays the role of bonding with EVA. The layer is a weather-resistant layer, which plays the role of resisting water vapor in the air, ultraviolet radiation, wind and sand and chemical erosion. It is generally a fluorine-containing film, such as PVF film, PVDF film, ETFE film, etc. PVF is polyvinyl fluoride and PVDF is Polyvinylidene fluoride, these two materials have relatively low fluorine content, good adhesion, and low selectivity to glue. ETFE is an ethylene-tetrafluoroethylene homopolymer with high fluorine content and is non-polar. Non-volatile materials, not easy to bond, the current conventional solar cell backsheet adhesive composite ETFE film mainly has the following disadvantages:

[0005] 1. Low interlayer peeling force: The conventional solar backsheet adhesive compounded with ETFE has an adhesive force of only 4N / cm. The low interlayer adhesive force means that the backsheet will lose its strength with the adhesion under long-term external environmental erosion. With the attenuation of the relay, the delamination cycle of the backplane is shortened and the probability is increased, which affects the service life of the backplane and components

[0006] 2. Poor aging resistance to humidity and heat: Conventional solar backplane adhesives are generally polyester and polyether polyurethane adhesives. The main chain of the adhesive contains a large number of ester bond groups, which has poor hydrolysis resistance and can only be resistant to double eight five 1000h, according to the theory of the corresponding relationship between double eighty-five aging and outdoor aging, double eighty-five 1000h corresponds to the actual service life of only 10 years outdoors

[0007] The inner layer of the solar battery back sheet is polyolefin material such as EVA or PE. Polyolefin material has low critical surface tension, high crystallinity, and PE is non-polar, which is a difficult-to-stick material. Generally, it needs corona treatment to make the film Hydroxyl, carbonyl and other surface active groups are produced on the surface, so as to achieve good adhesion between PE film and adhesive. In order to meet certain mechanical strength requirements, high molecular weight PE should be used as raw material for photovoltaic PE film to prepare solar cell backsheets. With the prolongation of humid heat aging time, the adhesive will be hydrolyzed, and the interlayer adhesion will decrease. PE is prone to shrinkage compared with polyester film, which will affect the bonding performance of the backsheet and EVA.

[0008] Chinese patent CN102887988A discloses a photovoltaic backplane adhesive and its preparation method. Two components are used, wherein, component A is a hydrolysis-resistant polyester polyol, and component B is an isocyanate curing agent. The isocyanate group in the isocyanate curing agent is The ratio of the hydroxyl group to the hydrolysis-resistant polyester polyol is 0.9~1.3:1, and a certain amount of anti-hydrolysis agent and silane coupling agent are added to the formula. Since the main component of the adhesive is still polyester, the overall The hydrolysis resistance is still poor, and it is not mentioned in the invention that it can achieve good adhesion to the difficult-to-stick ETFE fluorine film

The addition of a large amount of inorganic fillers will have an adverse effect on the adhesion of the adhesive to the intermediate insulating substrate, and the addition of nanomaterials will also have an adverse effect on the storage stability of the adhesive

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