Analysis of common quality problems in dustless paper products
Our company specializes in the production of industrial wipes, wipes, wipes, dust-free paper, dust-free cloth, oil-absorbing cotton and other products.
Analysis of common quality problems in dustless paper products:
Dust-free paper thickness and bulk index
The two indices are basically the same. Under the same quantitative conditions, the larger the thickness, the larger the volume. In the field of sanitary materials, such as manufacturing panties and sanitary napkins. Generally, the thickness requirement is proposed, because the greater the thickness of the same basis weight paper, the unit cost of the product will be greatly reduced.
For glued dust-free paper, the main influencing factors are:
(1) Fluff pulp factor: The longer the fluff pulp fiber, the higher the roughness, the better the bulkiness of the paper; the sulfate pulp and the bisulfate pulp have better bulkiness. Softwood pulp has better bulkiness than hardwood pulp. The bulkiness of untreated pulp is better than that of treated pulp;
(2) The higher the temperature and pressure of the press and embossing machine, the tighter the paper is pressed, the larger the volume, and the smaller the thickness;
(3) It is related to the retention rate of fine fibers in the forming part: In the production process, 80 mesh carbon mesh is generally used, and the fine fibers below 1.0 mm account for 5 %% of the total. If you control the degree of vacuum in the forming section to reduce the loss of fine fibers or recycle them, you can increase the bulk of the paper;
(4) It is related to the texture of the transfer mesh (embossed mesh), and the bulk of the paper produced by the plain mesh is better than other large textures;
(5) The bulkiness of the high basis weight paper is better than that of the low basis weight paper. On the one hand, it is because the fine fiber retention rate is high when forming the high basis weight paper; Much lower. Alas. For heat-sealed dust-free paper, in addition to the above factors, the main factor affecting the volume and thickness index is the oven temperature. Within the process allowable range, the higher the temperature, the better the hot-melt bonding conditions, and the higher the volume and thickness. Of course, some users may require thickness when ordering, so it must be adjusted according to the situation in the production process.
Softness index
Softness mainly depends on two factors: the hardness of the paper and the friction of the paper surface.
For glued dust-free paper, the main factors affecting the softness index are:
(1) Fluff pulp factor: The greater the roughness of the fluff pulp fibers, the greater the rigidity, the greater the surface friction of the paper, and the worse the softness of the paper; by comparing different fluff pulps, the overall situation is sulfite pulp The softness is better than sulfate pulp. The softness of treated fluff pulp (including semi-treated and fully treated) is better than that of untreated fluff pulp;
(2) It is also related to the retention rate of fine fibers during the forming process. When more fine fibers are retained, the paper becomes larger and feels softer;
(3) When the hot pressing pressure is high, the paper is tight and the softness is poor;
(4) Adhesive factors: First, the type of adhesive must be special latex for dust-free paper, which has a good feel. After some domestic VAF latexes are dried, the paper surface becomes hard and the softness is very poor. The second is the amount of adhesive. Under the condition of ensuring the strength, the less the amount of latex, the better, which not only improves the flexibility, but also reduces the cost. The third is the distribution of the adhesive in the paper. For example, when the adhesive is sprayed, the adhesive is evenly distributed on the inner and outer layers of the entire paper, which has good flexibility. When the adhesive is distributed more on both surfaces, the surface of the paper will change. It will be rough and hard, and the softness will drop sharply.
For heat-sealed dust-free paper, because it contains a small amount of latex and the hot-melt fiber itself is quite soft and elastic, the entire paper structure is loose, and its softness is generally better than glued dust-free paper. The influencing factors are mainly the effects of hot-melt fibers, except for fluff pulp. First, the softness of the hot-melt fiber itself; alas. The second is the thermal melting temperature. In the process range, when the temperature of the oven is low and the hot-melt bonding point is appropriately small, the upper part of the outer layer of the hot-melt fiber is melted, and the inner layer structure is intact. When the oven temperature is high, especially when the temperature exceeds the melting point of the outer layer, as the outer layer melting point and the bonding point increase, the paper gradually thickens, the hardness increases, and the softness decreases.
In addition, whether it is glued paper or heat-sealed paper, after being properly calendered and humidified during the roll paper finishing process, the softness is improved to varying degrees.
Generally speaking, it includes two aspects of lateral water absorption speed and saturated water absorption capacity. The lateral water absorption speed refers to the height of the liquid spreading along the paper within a certain time. Saturated water absorption capacity is the multiple of liquid that can be absorbed per unit mass of paper. As a highly absorbent product, dust-free paper is widely used in the field of sanitary absorbent materials, such as the absorbent core layer of sanitary napkins, watch pads, sanitary napkins, baby diapers and the like. Therefore, the liquid absorption capacity of the product has aroused great attention. For saturated water absorption capacity, currently adhesive paper can reach 7-9 times, heat-sealing paper can reach 15 times, without SAP.