Composite material nylon material for polymer lithium ion battery

Abstract

The invention which provides a nylon film material for a polymer lithium ion battery, which aims at providing a nylon of stable thermal property, superior longitudinal and transverse mechanical property, good compatibility of multilayer compositing, synchronous flow and consistent extension, and a manufacturing method of the nylon. The infill of nylon resin comprises enhanced graft POE or EPDM thermal-plastic elastomer and graft copolymer K-MAH, wherein the additive amount of the enhanced graft POE or the EPDM thermalplastic elastomer and the graft copolymer K-MAH at least accounts for 8-12 wt% of the total amount. The infill of nylon resin also comprises Kresin epoxy resin, N-butyl benzsulfamide, silane surface treating agent, silane-treated nano calcium carbonate and glass fiber. The additive amount of the glass fiber accounts for 30-35 wt% of the total amount. The copolymer (EVA) of ethylene-vinyl acetate is also added, wherein the additive amount of the EVA accounts for 10-16 wt% of the total amount. The problems of the excessive extension of BOPA (biaxially oriented polyamide) in the molding process, and layering, and bubbles appearing at the corners and folded edges in heat-sealing layer contraction when the contraction force is greater than the bonding intensity between a BOPA layer and a Al layer can be mainly solved.

Description

technical field [0001] The invention relates to a composite nylon material mainly used for polymer lithium ion batteries. Background technique [0002] Polyamide is commonly known as nylon (Nylon), and its English name is Polyamide (referred to as PA). It is a general term for thermoplastic resins containing repeated amide groups - [NHCO] - in the main molecular chain. PA is a high crystallinity polymer, which will crystallize immediately after stretching, so it cannot be stretched continuously. It must be produced by adding special additives in the traditional two-step production line, and the price is expensive. Nylon film is a product that is very easy to absorb moisture. After absorbing moisture, it will have adverse effects on use, such as dimensional changes leading to inaccurate printing during printing, and water film on the surface leading to insufficient composite strength and blistering. Nylon has a large number of modified varieties, such as reinforced nylon, mo...

AI Technical Summary

Problems solved by technology

In the prior art, in order to meet the multilayer co-extrusion compounding of the outer layer of the aluminum-plastic composite film soft packaging material used in the polymer lithium-ion battery, PET and nylon BOPA / aluminum foil are usually selected as the outer packaging barrier layer of the polymer lithium-ion battery. Layer co-extrusion compound usually uses many newly developed barrier materials with excellent barrier properties in recent years, such as MXD6 special nylon film and silicon oxide film as the barrier substrate for the outer layer of aluminum-plastic composite film flexible packaging materials used in polymer lithium-ion batteries. However, due to the large differences in the physical and mechanical properties of the above-mentioned materials in multi-layer co-extrusion, it is often difficult to meet the simultaneous molding of the outer barrier layer of the polymer lithium-ion battery, so that in the process of multi-layer co-extrusion, the fluidity of each layer of material The inconsistency of the cold stamping flexible packaging materials, which is the most difficult in terms of barrier properties, becomes extremely complicated among the cold stamping depth, the elongation of the aluminum foil, and the thickness change of the aluminum foil before and after cold stamping. After the extruded PP, PE or CPP and the outermost layer of nylon PA or PET of the aluminum foil are compounded, it is difficult to meet the cold stamping formability requirement. The cold stamping depth is 3-12mm or more. If the stamping depth is less than 3mm, delamination and cracking will occur. , pinhole light leakage, loss of shape retention, and unable to find a suitable solution

However, this method is difficult to make reinforced films due to the damage to the longitudinal orientation of molecules during transverse stretching and heat treatment.

In addition, since the heat treatment is carried out in the horizontal stretching machine, it is also difficult to produce a film with zero thermal shrinkage in the longitudinal direction

One of the disadvantages of the two-step method is that the bow effect is large, which will lead to poor surface balance performance of the BOPA film; while the simultaneous method can effectively improve this problem, but it also has poor BOPA film strength, film formation rate and production efficiency. low disadvantage

All in all, these two production processes have their own advantages and disadvantages that are difficult to integrate