PET bottle's anti-pollution improvement program

Many consumers have encountered such a situation: It is disgusting to find black moldy spots on the bottle after opening PET bottles. In the study of how to improve the contamination of the bottle mouth, this article describes the improvement plan for obtaining new and practical national patents.

The existing plastic beverage bottle with thread re-sealable bottle mouth is mainly made of PET, and the bottle cover is mainly HDPE. The sealing position is at the top of the bottle mouth, and seals and seals are respectively adopted according to the different pressure in the bottle. Rings, sealing plugs or sealing rings are used in combination with sealing plugs, and these differences in sealing form only have an effect on improving the sealing performance.

Since the sealing position is only at the mouth of the bottle and the threaded part is not sealed, many factors can cause contamination of the threaded part of the bottle from the production to the consumer's drinking. For example, during the filling of eutrophic beverages, the beverage splashes onto the thread of the bottle mouth. In some cases, under the action of bacteria and air, the bottle threads appear moldy and accumulate stains; or the poor environment of transportation and storage process leads to the contamination of the original clean bottle threads, such as long-term storage of ice in drinking water.

Many consumers will experience dirt found on the mouth of the bottle after opening the bottle cap, because the bottle cap has been opened, the effect of the complaint is limited, and they have to think of themselves as unlucky. In terms of drinking habits, most consumers do not use straws when drinking plastic bottled beverages. They use the mouth directly to contain the mouth of the bottle, and the contamination at the threads will enter the body. This phenomenon is especially prominent in children.

In fact, many beverage manufacturers face this problem and are also adopting various methods to solve such problems as controlling the filling volume, reducing the vibrations from filling and capping, and cleaning the bottle before capping, but still from time to time. This problem has arisen, and the current methods cannot be fundamentally solved. For example, the level of full mouth and spillage required for hot filling is a contradiction. This defective product sometimes even exceeds 1%. Manufacturers often have internal product recycling because of this problem. In addition, the pollution in the process of transportation and sale is also difficult to control. Finally, the products that flow to consumers are also numerous, resulting in complaints. Seriously affect product reputation.

From the analysis of the causes of the above defects, the problem is mainly that the bottle threads are not sealed. From the perspective of food packaging on the market, there are already some designs that protect consumers from direct contact with the parts, such as the rubber cover on rice pudding, but these packages It is added, the sealing effect is general, and the cost increases more. There is no such protective packaging in the plastic beverage bottle. So is there a simple and costless package? We propose a practical and feasible approach.

According to the principle of sealing, there are two main types of plastic beverage bottle seals mentioned above. One is the top seal in the bottle cap, the seal has one shape and the latter is added (two covers), and the second is the bottle mouth. Seal the plug. The seal gasket seals the seal on the top of the bottle and the inner plug seals by the interference of its outer diameter and the inner diameter of the bottle mouth. Due to different principles, the gasket caps can withstand relatively large pressures in the bottle, which are currently used in a variety of beverage plastic bottle packaging, and the use of the inner closure cap is relatively less commonly used in the bottle with no or less beverage pressure. Varieties, such as most current hot-filled beverages, have sealing properties that correlate with the inner diameter of the inner stopper and the inner diameter of the bottle mouth, as well as the inner plug material.

From the point of view of the production process, the inner stopper cap has a simple process, the cost is low, and the tightness of the re-tightening changes little, so it is widely used in non-carbonated beverages. From the perspective of its sealing principle, its sealability is not related to the final tightening torque of the cap. The actual tightening torque required for the actual production of the cap only prevents accidental loosening of the cap. Therefore, we can obtain the required bottle thread seal by improving the inner plug seal.

The above-mentioned two kinds of sealing principles are used in this kind of structure, and the sealing bosses are arranged below the male threads of the bottle mouth of the beverage bottle, and the inner side wall of the bottle cap forms the contact surface that is matched with the sealing boss and is at the contact surface. There is a gas seal ring, the gas seal ring can be integrally injection molded (pressure-molded) with a cap or a movable seal.
Before the bottle cap is tightened, the inner stopper is pressed into the bottle mouth to seal the beverage, and after tightening, the screw is pressed tightly to achieve the isolation of the thread from the beverage and the outside world. In this structure, the structure and position of the anti-theft ring are not changed. . Since the reliability of the two sealing principles has long been proven, the seal reliability of this structure is also indisputable. The specific dimensions of the bottle cap and bottle, especially the sealing part, can be designed according to the existing bottle cap and bottle, and the new structure is sealed. The performance will not be lower than the current structure of caps and bottles.

We simulated the actual production and storage conditions by making samples of new structure bottle mouth (87°C hot water cleaning cover, bottle threads, filling 87°C, 10% orange juice beverage, tightening torque of about 12LBS, contaminated beverage at the thread, larger room temperature Dust air was stored and stored in room temperature water for 3 months. No problems were found at the threads. At present, some inner stopper caps have a gas seal ring at the top of the inner cap, and the position E between the inner stopper and the gas seal ring is just like the thread position in the new structure we designed. We collect a large number of samples in different markets. No traces of mildew or stains were found there.

From an application point of view, this type of bottle and lid can also solve some of the problems that we encounter with current bottles and bottle caps. For example, the current hot filling products using the inner plug cap will have unscrewing torque after cooling compared to the screwing torque. The reason is that after the bottle is cooled, the size of each part becomes smaller, leading to a reduction in the tensile prestress of the cap thread and the cap top. During production, the torque of the screw cap has to be increased. For example, to achieve the unscrewing torque of 12LBS, the torque force must reach 28 LBS or more. This kind of situation requires high equipment and is difficult to control. The bottleneck bracket is prone to scratching. , affect the appearance of quality. The tightening and unscrewing forces of the new structure are determined by the compressive stress from the screw thread of the cap to the sealing gas ring. The reduction of the dimensions resulting from the cooling of the bottle will cause the original compressive stress to increase the fire, which is to achieve the required unscrewing torque. The tight torque force will be much less than the original, and the requirements for the capping machine will be reduced accordingly, the problem of scraping wire will be reduced, and the appearance quality will be more secure.

From the production process of caps and bottles, this new structure is realized just like the current bottle caps and bottles. Only from the technical point of view, there is no difficulty in adopting this kind of packaging structure. The production of bottle caps and bottles requires only the replacement of new molds. Equipment such as washing bottles, filling, and capping can be changed with only a few changes. As the weight of new caps and bottles has increased, beverages, the low-profit industry, will be more sensitive to digest the increased costs of this part. However, the increase in the cost of this part is insignificant in comparison with the damage to consumers' health and the image of the manufacturer. Once the new packaging is introduced to the market, consumers are aware of the defects in the current plastic beverage bottle packaging and have gained widespread recognition. This new packaging will quickly replace the old packaging, market demand is the eternal truth.