For this purpose, the author has analyzed and analyzed nearly 1,000 batches of corrugated paperboard test records. The result is that all the corrugated paperboard boxes have reached the original commodity inspection industry standard SN/T0262, accounting for 58% of the batches. Some of the items that failed to meet the standards were unqualified. 42%. In these failed projects, the appearance of 5%, burst strength of 6.6%, puncture strength of 9%, side pressure strength of 27, adhesive strength of 52%, anti-stress of 0.4%, and domestic related reports The statistics are basically similar. From the above statistics, it can be seen that the highest inconsistent frequency is the bond strength, followed by the side pressure strength. Both of these are exactly what the United States, Japan and Taiwan do not impose. In the above-mentioned carton non-conformity rate, the proportion of foodstuffs and electrical appliances each accounted for about 5 to 7%, and most of them are in footwear and clothing, especially shoe boxes, accounting for more than 80%. In the absence of people's understanding of the reasons for the high rate of unqualified cartons, many doubts, misunderstandings and different opinions naturally arise. Therefore, it is necessary to analyze these reasons first.
First, the reason
1. In terms of objective: Since the 1980s, the production of corrugated boxes in China has just started, the equipment of the factory is poor, the production process is backward, the quality of raw and auxiliary materials is not high, inspection standards and management measures have not kept up, and some manufacturers do not The legitimate business competition, mutual price, cut corners, shoddy, shoddy, corrugated carton quality was once seriously affected, coupled with relatively backward transport tools and means, rough handling and other reasons, resulting in damage to damaged packaging products, causing hundreds of countries each year The economic loss of 100 million yuan has seriously affected the reputation of China’s foreign trade and, to a certain extent, it has caused the impression of poor quality of corrugated boxes.
2. In terms of subjectivity, the responsibility for the damage caused by some human factors is also most affected by corrugated boxes. First, when a carton breaks, collapses, etc., or a built-in commercial accident occurs, people first blame the poor quality of the carton. I believe that this kind of blame is sometimes one-sided. The poor quality of the carton is an important cause of the above accidents, but it does not mean that the damaged carton quality will be poor. Some people do not attach importance to and care for packaging, improper stacking, rough handling, and even requalified carton boxes are difficult to withstand the "inadvertently" artificial destruction or rough handling. Second, a considerable number of carton users focus on light-weight packaging, and often try to reduce the cost of packaging according to their sales, transportation, and internal packaging (shoe boxes or linings). In order to win business, cartons manufacturing companies have overtook customer requirements. They often say: "Customer requirements are standards," and they are not produced according to standards. In order to seek profits, they have to reduce the quantification and grade of paper. The result will inevitably affect the quality of the carton. These undoubtedly also give people the impression of poor quality corrugated boxes.
3. There are too many mandatory items required, and the main item is not prominent. At present, the inspection and quarantine departments' inspection of corrugated boxes is mainly based on and in accordance with GB5033, 5034 and industry standards SN/T0262, 0608, 0714, 0715, 0717, 0718, 0720, etc. Each standard has slightly different inspection items for corrugated boxes. However, the basic requirement is that in addition to the 98 light defects and 3 heavy defects required for the inspection of its appearance, the performance test should be performed for its resistance to breakage, piercing, side pressure, adhesive strength and pressure resistance (stacking, Vertical impact drop test), SN/T0714 also required wet burst test. The general judgment is that “the appearance inspection, performance inspection, and type inspection are all qualified, then the inspection batch is qualified; as long as one failure occurs, the inspection batch is unqualifiedâ€. These requirements are indisputable for ensuring the quality of export cartons, reducing the loss of export goods, and improving China's foreign trade reputation. However, in implementing the above standards, many people also reflected the unreasonable problems of certain provisions of the standard, mainly as follows: 1 Regardless of the type of goods packaged (such as food, fragile goods or footwear and clothing) and the quality of contents Regardless of the size and value, and regardless of the carton or model, the standard value of the same adhesive strength is 588N/m2; 2 Compared with the United States and other countries or regions, there are too many mandatory items required in China and the pertinence is not strong. Regardless of the priority, it is not conducive to the improvement of the quality of the carton, and some even cause waste of packaging materials and high costs.
4. Adhesive strength standards are not perfect, directly affecting the carton pass rate. There are many factors that affect the adhesive strength of corrugated boxes. In addition to the quality of the adhesive itself, the quality of the paper, the moisture content of the paper, the quality of the blend, and the method of detection, it is also related to the conversion and evaluation of the test results. The new International GB/T 6548-1998 "Measurement of the Adhesive Strength of Corrugated Paperboard" has replaced the old standard of GB6548-86. The results of the old standard show that the right and left units do not match, that is, N/m = N/cm2. In the absence of dependability, people usually press the calculation method described in the book or training class, that is, the bonding strength A = F / (0.025X turns), this type can be referred to as "single length" calculation method , where A-bond strength, N/m 楞; F-sample is the average of the maximum force required for separation by all separations), N; number of turns - number of turns on the sample. When the same test value is converted to the bond strength value, there will be a large difference due to the difference in the number of turns taken by people. It is directly related to the judgment of whether the adhesive strength of a certain batch of carton is qualified or not. The prescribed value is now 25mm× 80mm sample, for example, some of the complete number of turns on the sample, such as A, C, B type, the three are generally 8~9, 10~11, 12~13, if a The mean value of F measured by the batch C sample was 160 N, and the number of turns was 11; the bond strength value of the sample was calculated to be 582 N/m, and the result was unqualified; while others were actually stripped from the sample. The number of turns, the same type, is generally 2 less than the total number of turns. If F is still 160N and the number of C type turns is 9, the value is 711N/m, which is much higher than the standard value. The new standard bond strength formula is: P = F / L, where P-bond strength, N / m; F the same as above; L-size of the sample long side (L = 0.0080m). Judging from the unit of the new standard, it seems that there is no difference between the "single length" calculation method used by people, but only a little "楞", but the meaning actually reflected in the formula is completely different, the latter can be abbreviated as The "area" calculation method indicates that the adhesive strength of the sample with a length of 1 m is actually on the surface. In fact, the width of the sample is 25 mm. If F = 160 N, the strength value is 2000 N/m regardless of the type. According to GB/T6544-1999 “Corrugated Paper for Packaging Materials†5.2.2, the standard still stipulates that “the adhesive strength of corrugated board should not be lower than 588N/mâ€, thus it can be seen that there is no According to the new qualification standard corresponding to the new standard, this value is obviously equal to 6kgf/楞10cm as specified in GB5034, and the aforementioned strong value is used as the criterion value? Since there is no conformity judgment value corresponding to the new standard, the calculation result of the new standard can only compare the magnitude of the value under the same cardboard and lose its role as the basis of judgment. Although some laboratories indicated testing and calculating the results according to the new standard of GB/T 6548-1998, the standard values ​​could not be listed on the report sheet. People could not determine whether the adhesive strength of the batch of corrugated cardboard was acceptable. In addition, the two calculation methods all ignore the fact that different strength levels are related to the width of the bonding lines of different types, which further explains the irrationality of specifying the same standard value. Therefore, at present, in the calculation of the adhesive strength of corrugated cardboard, it can be said that there is no standard in the name and standard.
Second, test results analysis 1. Bond strength and pressure, side pressure strength relationship. The tested samples (10 batches) are corrugated cartons of the same specification produced in the same production plant, the same raw material, and the same paper quantitative grade. The adhesive is made of corn starch and is formulated into different strength adhesives with different water ratios and additives. After testing, the relationship between the bond strength values ​​of 10 batches of samples and the values ​​of pressure resistance, burst strength, cut-through strength, and edge pressure strength is shown graphically (see attached figure). The results are as follows: 1 Bonding The relationship between strength and pressure resistance has been tested and proved to be a comprehensive indication of the quality of corrugated boxes, which is related to factors such as paper quantification, grade, type, box type, height, printing, staple length, moisture, etc. Affected by the bond strength. As can be seen from Figure 1, the pressure resistance increases or decreases with the strength of the bond within a certain range. When the bond strength increases to a certain value, the pressure resistance tends to be stable, and the bond strength decreases to a certain extent. After the value, the pressure resistance dropped sharply. 2 The relationship between adhesive strength and side pressure strength, in theory, the side pressure strength reflects the pressure resistance of the corrugated box from another angle, except for the paper (including core paper and corrugated paper), lap type, In addition to the thickness of the cardboard, it is also related to the bonding strength. As can be seen from FIG. 2 , the relationship between the adhesive strength and the side pressure strength and the relationship between the adhesive strength and the pressure resistance have similar characteristics.
2. Bond strength with burst strength, cut through the relationship between strength. Break strength and cut-through strength are both used to measure the resistance of the carton to breakage. The difference is that the former belongs to static strength and the latter belongs to dynamic strength. With the same quantitative grade, 楞-type and different adhesive strength cardboard, after the above two properties test, can be seen from Figure 3, Figure 4, although the adhesive strength changes greatly, but the burst strength and cut-through strength values ​​are basically Keep up and down in a small range. From this it can be seen that once the carton paper is determined, the strength values ​​of the two remain essentially the same. After consulting related data and combining test results analysis, even if the conditions of different materials, specifications, etc. are changed, only the specific test value is changed, but the relationship between adhesive strength and other properties reflected is Consistent.
Third, the actual use of the situation 1. After nearly 10 years of hard work, relevant departments have formulated relevant laws and standards, strengthened supervision and management, issued a series of policies and adopted effective measures, such as the implementation of a licensing system for export carton manufacturers, classification management assessment, and minimum quantification. With paper restrictions, etc., the export cartons production enterprises are accompanied by an orderly competition mechanism, so that most companies are moving toward the goal of "production scale, process level, management level, and quality level." The continuous improvement of the production process and the continuous renewal of equipment have resulted in the production of stand-alone machines, single-sided machines, double-sided machines and automatic production lines, which has greatly improved the appearance and performance indicators of the export cartons.
2. With the improvement of transportation conditions, the means of transportation and circulation have gradually become modernized, and manual handling methods have gradually been replaced by special mechanized operations. Bulk carriers for bulk carriers have been replaced by large trailers and container transportation, especially for “door-to-door†container transportation. The improvement of the road conditions has greatly reduced the damage rate of export cartons, and the number of accidents caused by the deterioration of cartons has been decreasing year by year. In the province for more than ten years, there have been no claims arising from the quality of the export cartons themselves.
3. Corrugated cartons are different from general merchandise, and their processing techniques, materials, types, structures, and specifications vary. Lots of inspection batches are large, and only 5,000 batches of corrugated cartons are accepted every year for inspection and quarantine in Putian. It stipulates that, for a type of management enterprise, 10% to 30% of the export batches will be sampled every year, and that for the second type of management enterprise shall be 30.