Jurečić, Denis (2015) Istraživanje čvrstoće ambalaže od valovitog kartona u kondicioniranim uvjetima = The research strength of the packaging of corrugated cardboard in terms of conditioned. Dissertation (PhD) thesis. Grafički fakultet. [Mentor: Babić, Darko].
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Abstract
Kutije od valovitog kartona za pakiranje voća i povrća susreću se na svom distribucijskom putu od proizvođača do potrošača s vrlo promjenljivim vremenskim uvjetima. Distribucijski put podrazumjeva najčešće dulji boravak u različitim hladnjačama pri prijevozu i skladištenju te kratkotrajno izlaganje vanjskim atmosferskim uvjetima pri pretovaru. U hladnjačama, radi očuvanja kvalitete i kvantitete voća i povrća, vladaju definirani uvjeti temperature i vlažnosti dok u vanjskoj okolini oni variraju. Izloženost tim promjenama ima nepovoljan utjecaj na mehanička svojstva valovitog kartona a posljedica je značajno smanjenje vijeka trajanja kutije. Cilj ovog istraživanja je razviti model ambalaže od valovitog kartona za predviđanje njene čvrstoće na tlačno opterećenje, bazirano na kondicioniranim uvjetima relativne vlažnosti i temperature okoline. Kako je agrokulturnoj industriji primarna briga težina i kvaliteta voća i povrća dok je ambalaža nužan izdatak koja mora opstati u datim uvjetima uz minimalan trošak. Cilj je otkriti informacije kojima ćemo odrediti donju granicu kvalitete kutije od valovitog kartona a kod koje postoji minimalna mogućnost njenog loma. Ispitivano je šest kvaliteta peteroslojnog valovitog kartona sa različitim kompozicijama slojeva papira različitih gramatura. Ispitivani su papiri od kojih je izrađen valoviti karton te kutije izrađene od tog valovitog kartona. Ispitivana je gramatura, debljina, otpornost na prskanje po Mullenu, otpornost horizontalne površine valovitog kartona na tlačnu čvrstoću, otpornost vertikalne površine valovitog kartona na tlačnu čvrstoću, sadržaj vlage u valovitom kartonu, otpornost valovitog kartona na dinamičko probijanje, otprnost kutije od valovitog kartona na tlačnu čvrstoću, relativna vlažnost zraka u hladnjači, relativna vlažnost zraka u okolini, temperatura hladnjače i temperatura okoline. Brojna mjerenja su interpretirana regresijskom analizom. Rezultati pokazuju velika odstupanja temperature i relativne vlažnosti zraka hladnjače i okoline. Prosječna razlika u temperaturi između hladnjače i vanjske okoline iznosi 23,88°C, dok je prosječna razlika relativne vlažnosti zraka u odnosu na okolinu 22,58%. Toplinska šokiranja kojima su bili izloženi uzorci kutija pokazuju velika odstupanja u tlačnoj čvrstoći. Uzorcima 2KŠ i 2KŠ-E tlačna čvrstoća pala je za 40% i nakon samo dva dana došlo je do urušavanja kupova na paleti. Ostali uzorci izdržali su ove drastične promjene. Mjeranja pokazuju da pad tlačne čvrstoće kod svih uzraka prati istovremeno veliko povećanje sadržaja vlage. Zaključak. Cikličke promjene relativne vlažnosti zraka uz zanemarivi utjecaj vremena trajanja opterećenja drastično smanjuju nominalnu tlačnu čvrstoću kutija od valovitog kartona. Skladištenje voća u hladnjači zahtjeva upotrebu visokokvalitetnih kartona proizvedenih od visokokvalitetne nereciklirane sirovine. Preporuke. Predlaže se analiza mjerenja kontrole kvalitete papira za ravni i valoviti sloj u samom proizvodnom procesu njegove izrade. Ovi podaci mogli bi se iskoristiti za određivanje utjecaja na graničnu tlačnu izdržljivost svakog sloja valovitog kartona kao i graničnu tlačnu izdržljivost kutije. Predlaže se i postavljanje barijere za vlagu na površinu valovitog kartona ali ta odluka trebala bi se bazirati na studiji o veličini i stupnju kruženja vlage.
| Item Type: | Dissertation (PhD) thesis |
|---|---|
| Mentor name: | Babić, Darko |
| Thesis Committee: | Žiljak, Vilko and Lajić, Branka and Sabati, Zvonimir |
| Defence date: | 23 December 2015 |
| Abstract in english: | Boxes made from the corrugated board for packing the fruit and vegetables meet very changeable weather conditions on their distribution way from the producer to the consumer. Longer stay in different cold storage plants during the transport and storage as well as the short exposition to the outer atmospheric conditions during the reloading is understood under the distribution way. In the cold storage plants, for preserving the quality and the quantity of the fruit and vegetable, there are defined conditions of temperature and humidity while in the outer environment they vary. The exposition to these changes has an unfavourable influence on the mechanical properties of the corrugated board and the consequence is the considerably decrease of the boxes lifespan. The aim of this investigation is to develop the model for prediction the box strength on the compression load, based on the conditioned state of relative humidity and the temperature in the environment. As the weight and the quality of fruit and vegetables is the primary care in the agricultural industry, the packaging is necessary expense which must survive in the given conditions with minimal costs. The aim is to find out the information which will determine the lower boundary of the corrugated box quality and the minimal possibility of its breakdown. Six qualities of the double – wall corrugated board with different composition of paper layers of different grammage were investigated. The papers used for the production of the corrugated board and the boxes produced from that corrugated board were investigated. The grammage, the thickness, the burst resistance per Mullen, the resistance of the horizontal surface of the corrugated board to compression strength, the resistance of the vertical surface of the corrugated board to compression strength, the humidity content in the corrugated board, the resistance of the corrugated board to dynamic penetration, the resistance of the corrugated board to compression strength, relative humidity of the air in the cold storage plant, relative humidity of the air in the environment, temperature of the cold storage plant and the temperature of the environment were tested. Numerous measurements were interpreted by the regression analysis. The results show great aberrations of temperature and relative humidity of the air in the cold storage plant and in the environment. The average difference in temperature between the cold storage plant and the outer surroundings was 23,88oC, while the average difference of the relative humidity of the air in regard to the environment was 22,58%. The thermal shock to which the box samples were exposed showed great aberrations in the compression strength. The compression strength of the samples 2KŠ and 2KŠ-E was decreased for 40%, and after only two days the stacks on the pallet imploded. The rest of the samples survived these drastic changes. Measurements show that the decrease of the compression strength of all the samples follows the simultaneous great humidity content increase. Conclusion: The cyclic changes of the relative humidity in the air, with the negligible influence of the time duration drastically decrease the nominal compression strength of the corrugated boxes. The storage of the fruit in the cold storage plants demands the usage of the high quality boards produced from the high quality non recycled raw material. The analysis of the paper quality control measurements for the flat and wall layer is suggested in its production process. These data could be used for determining the influences on the boundary compression durability of each layer of the corrugated board as well as the boundary compression durability of the boxes. The setting of the humidity barrier on the surface of the corrugated board is also suggested. This decision however should be based on the size and on the degree of the humidity circulation. |
| Subjects: | TECHNICAL SCIENCES > Graphic Technology |
| Institution: | Grafički fakultet |
| City: | Zagreb |
| Number of Pages: | 98 |
| Callnumber: | 621.798 JUR i |
| Inventory number: | 10115 |
| Depositing User: | Nina Jelača |
| Status: | Unpublished |
| Date Deposited: | 12 Feb 2016 10:01 |
| Last Modified: | 02 Mar 2016 13:09 |
| URI: | http://eprints.grf.unizg.hr/id/eprint/2474 |
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