Coating type multi-layer composite high-barrier film as well as preparation method and application thereof

Abstract

The invention relates to a coating type multilayer composite high-barrier film, a preparation method and application thereof, wherein the coating type multilayer composite high-barrier film is formedby compounding multilayer polymers through a coating composite molding method; the structural expression is A / (adh / C)n / B / (adh / C)n / adh / A; in the formula, n is an integer greater than 0, the A represents a surface layer, the B represents a barrier layer, the adh represents an adhesive layer, and the C represents an additional layer. The barrier layer B is a PVA-EVOH composition which is prepared from the following raw materials in parts by weight: 40 to 80 parts of PVA, 15 to 30 parts of EVOH, 5 to 30 parts of plasticizer, 0.5 to 10 parts of heat stabilizer and 0.1 to 2 parts of metal salt; andthe surface layers A and C are thermoplastic high-molecular polymers. The film disclosed by the invention has excellent strength and oxygen-blocking and water-blocking properties, and can be applied to the field of packaging of various foods, medicines and the like.

Description

technical field [0001] The invention relates to the field of material processing, in particular to a coating type multilayer composite high barrier film and a preparation method thereof. Background technique [0002] According to reports, the world produces about 4 billion tons of food every year, and 30% to 50% goes uneaten due to loss and waste. The waste of medicines is equally serious. Every year, the waste of medicines caused by expired medicines in my country is worth hundreds of billions of dollars. How to reduce the loss and waste of food and medicine is the focus of global attention. Research and analysis of the entire process of food and drug production, processing, storage, distribution, and the hands of consumers shows that the use of high-barrier composite packaging films can block oxygen and water vapor, extend shelf life, and reduce food and drug loss and waste. The following problems exist in the development of the film industry: the price of the commonly u...

AI Technical Summary

Problems solved by technology

Research and analysis of the entire process of food and drug production, processing, storage, distribution, and the hands of consumers shows that the use of high-barrier composite packaging films can block oxygen and water vapor, extend shelf life, and reduce food and drug loss and waste. The following problems exist in the development of the film industry: the price of the commonly used high-barrier composite film is too high; the use of solvent-based adhesives in the traditional composite process will cause problems such as air pollution, health and safety, etc.

[0003] The development of the high-barrier composite packaging film industry faces the following problems: (1) The price of barrier layer EVOH in the commonly used high-barrier composite packaging film is too high (40,000-50,000 / ton), although the price of PVA is low (10,000 / ton), It has excellent performance, but it cannot be melt-processed, and it is easy to absorb water, and the barrier performance will decrease after absorbing water; (2) Solvent-based adhesives are used in the traditional composite film preparation process. Hygiene and safety; (3) It is now stipulated that all plastic packaging shall be recycled and reused before 2030. In order to meet this requirement, the material of composite packaging film shall be as simple as possible, and the proportion of non-single material shall not exceed 5%. is a challenge

However, at present, a large number of intramolecular and intermolecular hydrogen bonds are easily formed between adjacent hydroxyl groups in the PVA polymer chain, making its thermal decomposition temperature (200-250 ° C) close to the melting point (226 ° C), and thermal decomposition occurs when melting, so it is difficult to Thermoplastics are processed into films, and PVA films are easy to absorb water, and the barrier performance decreases after absorbing water; at the same time, gel phenomenon is prone to block the die during PVA processing

The patent of CN 105777949A discloses a polyvinyl alcohol coating film-forming solution for coating composite films and its preparation method and application, but its pre-treatment of PVA is complicated and not suitable for industrial production

Due to the large difference in melting point between EVOH resin and PVA resin, they usually cannot be directly blended

The patent of CN107163465A discloses a kind of high barrier property coating material and its preparation method, and material comprises modified EVOH film, is coated with PVA nano TiO on the inner surface of modified EVOH film 2 Sol, the process is complicated

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