Three-layer ethylene vinyl acetate copolymer negative pressure casting film and preparation method thereof

A technology of ethylene vinyl acetate copolymer and ethylene vinyl acetate, which can be used in casting and molding equipment, chemical instruments and methods, layered products, etc., and can solve problems such as easy breakage and stickiness

Active Publication Date: 2011-12-21
WUHAN HENGDE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Ethylene-vinyl acetate copolymer (EVA), the use of ethylene-vinyl acetate copolymer (EVA) as the film for V-casting has become a consensus in the industry. Because the higher the acetic acid content in the EVA raw material, the better the tensile properties of the film, but at the same time the more Easy to stick, easy to damage, air leakage destroys vacuum molding

Method used

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  • Three-layer ethylene vinyl acetate copolymer negative pressure casting film and preparation method thereof

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Effect test

Embodiment 1

[0015] Add 60Kg of ethylene vinyl acetate copolymer with a molecular weight of 20,000 to 500,000, 13Kg of low-density polyethylene with a molecular weight of 200,000, and 60g of oleic acid amide into three mixing bodies according to the materials used in the upper, middle, and lower layers. Add the ethylene vinyl acetate copolymer of 6.5Kg low-density polyethylene, 30g oleic acid amide and 5Kg respectively in the stirring body of the lower layer of materials, and the remaining 50Kg of ethylene vinyl acetate copolymer is added into the stirring body of the middle layer of materials, Fully mix, and then suck it into the discharge port of the extruder through the suction machine, the three extruders move in the same direction, and gather at the upper end of the die in three different flow channels to form a three-layer affinity The integrated liquefied body is blown by air, shaped, cooled and shaped to produce a three-layer composite negative pressure casting film of ethylene viny...

Embodiment 2

[0017] Add 80Kg of vinyl acetate copolymer with a molecular weight of 20,000 to 500,000, 10Kg of low-density polyethylene with a molecular weight of 200,000, and 50g of oleic acid amide into three mixing bodies according to the materials used in the upper, middle and lower layers. Add 5Kg of low-density polyethylene, 25g of oleic acid amide and 5Kg of vinyl acetate copolymer to the mixing body of the material for the lower layer, and add the remaining 70Kg of ethylene vinyl acetate copolymer to the mixing body of the material for the middle layer, and fully stir Then they are sucked into the discharge port of the extruder through the suction machine respectively. The three extruders move in the same direction and gather at the upper end of the die in three different flow channels to form a three-layer affinity integrated liquefaction The body is blown by air, shaped, cooled, and formed to obtain a three-layer composite negative pressure casting film of ethylene vinyl acetate co...

Embodiment 3

[0019] Add 70Kg of ethylene vinyl acetate copolymer with a molecular weight of 20,000 to 500,000, 15Kg of low-density polyethylene with a molecular weight of 200,000, and 15g of oleic acid amide into three mixing bodies according to the materials used in the upper, middle and lower layers. Add 7.5Kg of low-density polyethylene, 7.5g of oleic acid amide and 7.5Kg of ethylene vinyl acetate copolymer to the mixing body of the material for the lower layer, and add the remaining 55Kg of ethylene vinyl acetate copolymer to the mixing body of the material for the middle layer Fully mixed, and then sucked into the discharge port of the extruder through the suction machine, the three extruders move in the same direction, and gather at the upper end of the die in three different flow channels to form three layers Affinity integrated liquefied body, after air inflation, shaping, cooling and forming, the three-layer composite negative pressure casting film of ethylene vinyl acetate copolym...

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Abstract

The invention relates to an ethylene-vinyl acetate copolymer negative pressure casting film and a preparation method thereof. The content of the ethylene-vinyl acetate copolymer is 79.8-89.8%, the molecular weight of low-density polyethylene is 10-20%, and the oleic acid amide is 0.1-0.2%. The preparation method: The above three materials are respectively added into three mixing bodies according to the upper, middle and lower layer materials, and half of the low-density polyethylene, half of the oleic acid amide and 5-10 % of ethylene-vinyl acetate copolymer, and the remaining ethylene-vinyl acetate copolymer is added to the mixer body of the middle layer material, fully mixed, and then sucked into the discharge port of the extruder through the suction machine, three extruders The extruder moves in the same direction, and gathers at the upper end of the die in three different flow channels to form a three-layer affinity integrated liquefied body, which is blown by air, shaped, cooled, and formed to produce negative pressure ethylene vinyl acetate copolymer. cast film. The film prepared by the invention satisfies the extensibility requirements of the film for V-method casting, and can ensure that the film and the model are not sticky.

Description

technical field [0001] The invention relates to a three-layer ethylene-vinyl acetate copolymer negative pressure casting film and a preparation method thereof. Background technique [0002] V method molding, also known as vacuum negative pressure molding, vacuum sealing molding, is a new type of environmentally friendly physical molding method for dry sand curing. In this process, the plastic film is heated and molded on the wooden mold with ventilation holes and air extraction device. After placing the sand box, fill in fine dry sand as molding sand, vibrate tightly and cover the back film, and rely on the vacuum pump to draw out the mold. The air in the sand mold creates a vacuum in the inner cavity of the sand mold, forming a pressure difference between the inner cavity of the sand mold and the atmospheric pressure, so that the dry sand can be solidified without any binder. Form the desired cavity. [0003] Since the film is to be covered on the wooden mold with the sam...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22C7/02B32B27/30B29C55/28C08L23/08C08L23/06C08K5/20
Inventor 刘德汉
Owner WUHAN HENGDE TECH
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