Shanghai Daoqin Plastics Co., Ltd.

add hot temperature degree control:  

    temperature degree is rotational molding process can or elements, especially add hot process in temperature degree control is improve/increase product quality most main/primary 手段. polyethylene (PE) is 例说明 this issues, polyethylene (PE) rotational molding process process has 一 特殊 phenomenon: in powder melt process in, powder pellets between 滞留 空 gas formed bubbles, add hot process 持续, this bubbles also 消失. 进一步 research table/sheet 明, this bubbles 消失并 non due to it in force function lower toward melt 自由面, is is bubbles in gas melt combined in melt plastics melt in. therefore, for/regarding polyethylene (PE) rotational molding 说, control add hot process for remove polyethylene (PE) products in bubbles, improve/increase product quality has separation important 意义.  

    due to rotational molding add hot time has relatively long, especially is products relatively thick 时, can can 会持续 semi small to small above. this requirements measures anti material in add hot process in hot oxidation and material property can reduce, usually in polyethylene (PE) plastics in add resistant oxidation agent can to anti 目. is, polyethylene (PE) material by add hot to high temperature degree or add hot time long 时, resistant oxidation agent can anti material oxidation. products thick degree relatively large need add hot relatively long time 时, must reduce add hot temperature degree. if utilizing improve/increase temperature degree shrink short add hot time, has can can bubbles in gas and 消失而 make bubbles lower. polyethylene (PE) plastics by add hot to melt 状态时, material will 经历一 from crystallization toward melt process, this positive is polyethylene (PE) pellets 开始熔化变 soft 时 发生 process. it 首先出现 in and mold inner 壁接触 一层材 material, formed uniform melt material 层. rear, toward inner expand 展, to full 截面完 full formed plastics melt is 止. lower is add hot make bubbles 逐渐消失 process. this process temperature degree control and time control need adjustment.  

    cooling process control:  

    in cooling process in, polyethylene (PE) melt temperature degree will from 200℃ drop 至接近 room temperature, polyethylene (PE) separation will from 无序 状态转变 is relatively is has crystallization 态, crystallization process need time, crystallization speed degree and polyethylene (PE) melt viscosity has 关. polyethylene (PE) melt by speed cooling 时, polyethylene (PE) melt viscosity speed increase, make its 晶粒 生 long to retardant 碍, from effect/influence polyethylene (PE) crystallization degree. crystallization degree meanwhile, polyethylene (PE) products density different, physical properties will has 差别. 由此, speed cooling polyethylene (PE) rotational molding products tool has relatively low density, slow cooling products tool has relatively high density. 当然, products cooling slow, its production cycle long, cost high. used for rotational molding production polyethylene (PE) powder 末本身 tool has density, it 决定于材 material production 厂家. rotational molding production rear, due to cooling speed degree different, polyethylene (PE) rotational molding products density will 发生一定 变化, and for product shrinkage has effect/influence