微孔对复合纸基包装浅盘性能影响的研究

发布时间：2018-06-04 17:56

本文选题：气调包装 + 微孔　；参考：《天津科技大学》2017年硕士论文

【摘要】：热压成型淋膜纸板浅盘和上层热封薄膜构成的浅盘包装在欧美及其他国家已被应用于食品包装。打孔气调包装则是果蔬包装一项常用的技术。本研究结合当浅盘应用于果蔬包装时,生产商一般会在上层封合薄膜表面打孔的现状,采用将微孔分布于包装浅盘侧壁的研究方法,以期解决三个问题。一是当封合薄膜为生物塑料时,由于其较非生物塑料更脆,打孔将严重降低浅盘的机械强度;二是在运输和仓储过程中,浅盘呈堆码状态,下层浅盘的微孔可能会被上层浅盘的底部压住,影响气体交换;三是果蔬的呼吸作用会产生水分,包装内易形成凝露,若将微孔排布在上层薄膜上,微孔则可能会被凝露堵塞,而若将其排布在浅盘侧壁上,则不会受到凝露的影响。本课题是基于在浅盘侧壁打孔以提高包装保鲜功能的想法,来研究开孔方法以及微孔排布对包装浅盘整体性能影响的。本课题探究了在纸基包装浅盘侧壁打孔对浅盘性能的影响。研究综合国内外已有研究进行了全面的文献综述,深入地探究了微孔的排布方式和打孔方式对浅盘机械性能的影响。另外,针对其对包材的透气透湿性能的影响作了简要的讨论。研究中对微孔在试样上的分布进行了实验设计,观测比较了不同种纸板材料不同打孔方式所得微孔的结构、外观和大小,以及试样的断面结构。研究中对机械打孔和激光打孔所得微孔的形貌作了观测。在微孔排布对纸基浅盘机械性能的影响方面,采用多种方法进行了仔细的分析。通过实验和分析,得出以下的结论:在手工打孔条件下,在样条宽度方向上,随着打孔数增多,试样机械强度下降,当超过5个孔时,下降明显。从25种打孔排布来看,在横向同一排最多打4个孔的情况下,试样机械强度最大下降了 22%。孔的排布越分散,试样的拉伸性能的损失越小。沿宽度方向打孔数量的增加会降低试样的拉伸强度。样张横向与纵向测试结果差异明显,且变化趋势并不完全一致,这都是由于纸张抄造过程中的方向性造成的。激光打孔后的抗张强度测试,变化趋势并不明显。综上所述,微孔对浅盘包装机械性能的影响完全是在合理的范围内的。在三种试样中,未淋膜纸板具有最高的水分透过率,其次的是PET淋膜纸板,第三是PE淋膜纸板。测试打孔密度可提高PET淋膜纸板的水分透过率约42%。不同种材料激光打孔后外观有明显区别,激光打孔得到的微孔,相较于机械打孔,更加平滑,直径也更小。
[Abstract]:The hot-pressed coated paperboard and the upper-layer hot-sealed film are used in food packaging in Europe, America and other countries. Perforated atmosphere packaging is a common technology for fruit and vegetable packaging. In this study, when the shallow disk is used in the packaging of fruits and vegetables, the manufacturer generally punches holes on the surface of the upper sealing film, and adopts the method of distributing the micropores on the side wall of the shallow disk in order to solve the three problems. One is that when the sealed film is bioplastic, because it is more brittle than non-biological plastic, punching will seriously reduce the mechanical strength of the shallow disk; second, during the transportation and storage process, the shallow disk is stacked. The micropores of the lower shallow disk may be pressured by the bottom of the upper shallow disk, affecting the gas exchange; third, the respiration of fruits and vegetables will produce moisture, which will easily form condensation in the package. If the micropores are arranged on the upper layer film, the micropores may be clogged by condensation. If it is arranged on the side wall of the shallow disk, it will not be affected by condensation. Based on the idea of perforating the sidewall of shallow disk to improve the function of packaging preservation, this paper studies the effect of opening method and micropore arrangement on the whole performance of shallow disk. The paper explores the effect of sidewall perforation on the performance of paper-based packaging. In this paper, a comprehensive literature review has been carried out, and the effects of the arrangement and punching of the microholes on the mechanical properties of the shallow disk have been deeply explored. In addition, the effect on the permeability of the package is discussed briefly. In the study, the distribution of micropores on the sample was designed experimentally, and the structure, appearance and size of the micropores and the cross-section structure of the samples were observed and compared with different kinds of paperboard materials. In the study, the morphology of the micropores obtained by mechanical and laser drilling were observed. The influence of micropore arrangement on mechanical properties of paper-based shallow-disk is analyzed in detail by various methods. Through experiment and analysis, the following conclusions are drawn: under the condition of manual drilling, the mechanical strength of the sample decreases with the increase of the number of holes in the width direction of the spline, and the decrease is obvious when the hole is more than 5 holes. According to 25 kinds of perforating arrangement, the maximum mechanical strength of the sample decreases by 22 when 4 holes are punched in the same horizontal row. The more dispersed the pore is, the smaller the loss of tensile properties of the sample is. The increase in the number of holes in the width direction will reduce the tensile strength of the sample. The results of transverse and longitudinal tests are obviously different, and the variation trend is not completely consistent, which is caused by the directionality in the process of paper making. The change trend of the tensile strength after laser drilling is not obvious. To sum up, the effect of micropores on the mechanical properties of shallow disk packaging is completely within a reasonable range. Among the three samples, uncoated paperboard has the highest water transmittance, followed by PET coated board and PE coated paperboard. The water transmittance of PET coated board can be increased by measuring the perforation density. There are obvious differences in the appearance of different materials after laser drilling. Compared with mechanical drilling, the microholes obtained by laser drilling are more smooth and smaller in diameter.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB48

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