TON BAG DESIGN

Ton bag

With the continuous growth of the international market demand for tons of bags, China's export volume of tons of bags to further increase, at the same time, the international market on the quality requirements of tons of bags more stringent. Therefore, how to improve the ton bag strength of the products, select the appropriate raw materials, tons of bags of reasonable skills; how to implement the national standards under the premise, combined with the actual situation of enterprises, design a high quality tons of bags, is an important topic in front of the ton bag production enterprises. This paper expounds several problems needing attention in the design of ton bag. The bag is made of polyolefin resin through the wire drawing process, and then the film is cut into different sizes, such as cylinder or flake substrate, and then according to the design requirements of the substrate into a round or square shaped bag products. Tons of bags is a flexible transport container, excellent performance with plastic light, soft, acid and alkali resistance and moisture, no leakage; has enough strength in structure, and has strong safety, convenient operation, container unloading, adapt to the characteristics of mechanical operation, can be widely used in chemical, cement, food mineral products, and other types of powder, granular, bulk goods packaging.

The basis and principle of the ton bag design

T bag design to strictly enforce the national standard of GB / T10454-2000. Tons of bags as export packaging, to ensure that the export of goods in the process of loading and unloading, transportation and storage of goods in the process of effective protection, safe and complete delivery of goods to the destination. Therefore, the design must meet four main points, that is, safety, storage, use, sealing.

Safety

Mainly refers to the strength of the bag. In the design to consider the volume of packaging, the carrying capacity of the goods and packaging units (the number), but also to consider the distance of transport distance and the number of handling, how to use the means of transport and transport. In the national standard of GB / T10454 - 2000 tons bag, the technical requirements of the ton bag base cloth and sling are strictly defined. From the point of view of safety, it is clear that the structure of the bottom of the bag is all the bottom structure. Safety factor must reach 1:6.

Safekeeping

Should be based on the user's conditions of use, reasonable selection of materials, reasonable ratio. Plastic products in the sun under the aging resistance is currently more concerned about the problem, but also in the actual use of tons of bags often encountered problems. Pay attention to the use of anti violet agent and the choice of materials in the production process.

Usability

In the design of the bag, we should give full consideration to the specific methods and methods of the use of tons of bags, such as lifting, transportation, loading materials, etc.. In addition to consider whether it is food packaging, food packaging should be considered non-toxic, harmless.

Sealing property

Different packaging materials, sealing requirements. Tons of bags, such as powder or toxic substances, fear of contaminated items on the sealing performance requirements are very strict, easy to damp or moldy materials have special requirements for air tightness. Therefore, in the design of the bag, pay attention to the consideration of the substrate coating process and sewing process on the impact of sealing.

Problems should be paid attention to in design ton bag

Choose the best fabric

In the design of the bag, the first clear load of goods, according to the proportion of the material to determine the volume of the bag. Depends on whether the loading material is a sharp and hard block material, such as, the design of the bag when the fabric selection to be thick, on the contrary can be thin. In the actual design, the weight of 500kg tons of bags, the substrate is generally selected (150-170) G / m2, vertical and horizontal tensile strength (1470-1700) N / 5cm, elongation 20-35%. Tons of bags above 1000kg. Base fabric generally choose (170~210) G / m2, vertical and horizontal tensile strength (1700-2000) N / 5cm, elongation 20~35%.

Increase the strength of single fiber

Tons of bags to ensure the fabric strength, must improve the tensile strength of the flat wire. Flat relative strength should reach 0.4N / tex, elongation of 15-30%. In the actual production process, the need to strictly control the amount of filler masterbatch, generally around 2%. If the masterbatch is too much, or add recycled materials, will lead to lower strength. Therefore, the quality of raw materials should be strictly off, tons of bags to melt index to achieve the national standard manufacturers of raw materials.

Choose the best sling

In the design of the ton bag, sling selection is crucial. National standard clearly defines the safety factor of 1:6. Tons of bags in the actual design, one should consider the sewing process of the loss of the strength of the sling; two to consider the lifting method. For example, the load of 500kg tons of bags, sling generally used (50 - 60) g / M (1300-1800), tension in the N / M; the load of 1000kg tons of bags with (60-75) g / m, N / M tension (1800-2100), requirements must meet the requirements of knitting density sling. Tons of bags in addition to the design of the sling, you can choose two rings, the fourth ring and other ways to increase the tensile strength.

Add additives, prolong service life

In order to improve the anti-aging ability of plastic bags tons in the sunlight, in the drawing process to add flat UV resistant agent and stabilizer amount. According to the length of the bag (half a year or one year) to determine the amount of increase in general (0.1~3)%. Some enterprises by adding stabilizer, anti violet agent and other additives made of anti-aging masterbatch, the effect is also very good.

Structural design

The design of the bag structure, the national standard for the strength of the waist hoop should be more than two times the strength of the substrate, but the actual design effect is not good, because the substrate and the waist hoop strength is inconsistent, resulting in the first crack. In the design, the waist hoop and the base cloth selects the same intensity the base cloth material, may avoid this question.

Sewing process design

In addition to the national standard of sewing requirements, but also consider the ton bag sutures are resistant to the effects of aging resistance and tensile strength of stitched fabric. In the packaging powder, toxic, fear of contaminated items, first of all to solve the sealing problem. Therefore, in the actual design, the use of thick or thin line of bags, or non-woven fabric and fabric sewing together to improve the sealing. In addition, in the sewing bag, the requirements of the strength of the suture must be more than 18kg polyester line, to ensure that the sewing strength of gb.

Inlet and outlet design

The import and export of material base of longitudinal and transverse tensile strength more than 828N / 50mm in national standard, but in actual design, because the outlet tension can be larger, higher, feeding intensity can be low, generally used in coated fabric (90 - 100) S / m2.

Other factors

In the process of design and experiment, the ton bag with the bottom hanging structure without feeding mouth can meet the safety factor of the national standard. But there is a discharge port, tons of bags, strength is not up to the standard, which requires in the design to consider increasing the bottom opening strength, such as by increasing the bag bottom cloth thickness, increase the feed opening reinforcement cloth, can solve this problem. Tons of bags in the actual design process, to considering all the factors, continuous improvement of process design, strengthening technological innovation, the use of new materials, new technology and method to seek the best solution in the design, to ensure the quality of design.

吨袋

随着国际市场对吨袋产品需求的不断增长，我国吨袋产品出口量进一步增加，与此同时，国际市场对吨袋产品的质量要求愈加严格。因此，如何提高吨袋产品强度，选择合适的原料，吨袋合理的工艺配比；如何在执行国家标准的前提下，结合企业的实际情况，设计出高质量的吨袋，是摆在吨袋生产企业面前的重要课题。本文阐述了吨袋设计中需注意的几个问题。吨袋是采用聚烯烃树脂经拉丝织造工艺，再经涂膜后裁切成大小不等的筒状或片状基材，然后按设计要求将基材缝制成圆形或方型的袋状产品。吨袋是一种柔性运输包装容器，具有塑料的轻便、柔软、耐酸碱腐蚀及防潮、不渗漏的优异性能；在结构上具有足够的强度，并具有牢固安全，集装、集卸操作方便，适应机械化作业的特点，可广泛用于化工、水泥、粮食、矿产品等各类粉状、粒状、块状物品的包装。

吨袋设计的依据和原则

吨袋设计要严格执行GB／T10454-2000国家标准。吨袋作为出口包装，要保证出口货物在装卸、运输和保管过程中有效地保护装载物品，安全完好地将货物运至目的地。因此，吨袋设计必须满足四大要点，即安全性、保管性、使用性、密封性。

安全性

主要指吨袋的强度。在设计时要考虑包装容积、盛载物重量和包装单位(个数)，还要考虑运输距离的远近和搬运次数的多少，采用何种运输工具和运输方法。在 GB／T10454—2000吨袋国家标准中，严格规定了吨袋基布和吊带技术指标要求，从安全角度出发，明确了吨袋结构全部为底吊结构。安全系数必须达到1：6。

保管性

应根据用户的使用条件，合理的选用材料，合理的配比。塑料制品在阳光暴晒下的抗老化能力是目前比较关注的问题，也是吨袋在实际使用过程中经常遇到的问题。在生产过程中注意抗紫剂的使用以及材料的选择。

使用性

在设计吨袋时，要充分考虑客户使用吨袋的具体方式和方法，如提吊、运输方式、装载物料性能等。另外还要考虑是否为食品包装，要考虑对所包食品无毒、无害。

密封性

包装物料不同，密封要求不同。吨袋如粉料或有毒物品、怕受污染的物品对密封性能要求非常严格，容易受潮或霉变的物料对气密性也有特殊的要求。所以在设计吨袋时，注意考虑基布覆膜工艺和缝制工艺对密封性的影响。

设计吨袋应注意的问题

把好基布选材关

在设计吨袋时，首先明确装载货物的重量，根据所包物料比重确定吨袋容积。还要看装载物料是否是锋利坚硬的块状物料，如是，设计吨袋时基布选材要厚一些，相反可薄一些。在实际设计中，载重500kg的吨袋，基布一般选用(150-170)G／m2，基布纵、横向抗拉强度(1470-1700) N／5cm，伸长率20-35％。载重1000kg以上的吨袋。基布一般选用(170~210)G／m2，基布纵、横向抗拉强度(1700-2000) N／5cm，伸长率20~35％。

提高单丝强度

吨袋要保证基布强度，必须提高扁丝的拉伸强度。扁丝相对强度应达到0．4N／tex以上，伸长率15-30％。在实际生产加工过程中，需严格控制填充母料的用量，一般在2％左右。若母料添加过多，或添加再生料，会导致基布强度降低。所以在原料上要严把质量关，吨袋选用熔融指数达到国标的正规厂家生产的拉丝原料。

把好吊带选材关

在吨袋设计中，吊带选材至关重要。国标中明确规定了1：6的安全系数。吨袋在实际设计中，一要考虑缝制过程对吊带强度的损耗；二要考虑吊装方式。例如载重 500kg吨袋，吊带一般选用(50—60)g／m，拉力在（1300-1800）N／m；载重1000kg的吨袋一般选用(60-75)g／m，拉力(1800-2100)N／m，要求吊带必须达到编织密度要求。吨袋另外设计吊带时，可选用两环、四环等方式来增加抗拉强度。

填加助剂，延长使用寿命

为了提高塑料吨袋在阳光照射下的抗老化能力，在扁丝拉伸工艺中要填加一定量的抗紫剂和稳定剂。根据吨袋使用期(半年或一年)的长短，确定添加量，一般在(0.1~3)％之间。有些企业添加由稳定剂、抗紫剂及其它助剂混合制成的抗老化母料，效果也很好。

结构设计

设计吨袋结构时，国家标准中规定腰箍强度应达到基布强度的两倍以上，但实际这样设计效果并不好，由于基布与腰箍强度不一致，导致基布先开裂。在设计时，腰箍与基布选用相同强度的基布材质，可避免这个问题。

缝制工艺设计

除按国标规定的缝制要求以外，吨袋还要考虑缝线的耐老化性能和缝针对基布抗拉强度的影响。在包装粉料、有毒、怕受污染的物品时，首先要解决密封性问题。所以在实际设计中，吨袋选用粗线细针或采用无纺布与基布一起缝纫，使密封性提高。另外，在缝制吨袋时，要求缝线选用强度必须达到18kg以上的聚酯线，保证其缝纫强度达到国标。

进出料口设计

国家标准中规定进出料口基布纵、横向抗拉强度≥828N／50mm，但在实际设计中，由于出料口承受拉力较大，可高一些，进料口强度可低一些，一般选用覆膜基布(90—100)S／m2。

其它因素

在设计、实验过程中，无进料口的底吊结构的吨袋，一般都能达到国家标准规定的安全系数要求。但有出料口的吨袋，强度一般达不到标准，这就要求在设计时考虑增加底部开口强度，如采用增加袋底基布厚度、增加料口补强布等，可解决这个问题。吨袋在实际设计过程中，要综合考虑各项指标，不断改进工艺设计，加强技术创新，采用新材料、新工艺、新方法，在设计中寻求最佳方案，确保设计质量。