The most important difference between composite spunlace nonwoven and ordinary spunlace nonwoven in terms of function is:the use of natural plant fiber,more environmentally friendly,
can be naturally degraded,the product has a unique absorption capacity and liquid absorption capacity,superior dust-free,soft,anti-static,do not damage the surface performance of objects and strong and durable performance,without the use of any chemical additives.
As the main composite material of wood pulp spunlace,the performance of raw paper directly affects the spunlace process and the later use.This paper discusses the use of a certain proportion of pulp,through a special pulp breaking,grinding,
copying process,the production of medium and high-grade wood pulp spunlace nonwoven raw paper,in order to replace imported products.
1、Spunlace nonwoven raw material selection
Coniferous pulp is more adaptable to the wood pulp spunlace nonwoven raw paper without lint,soft,good liquid absorption,good dimensional stability,
longitudinal and horizontal dry and wet strength characteristics,to achieve the composite and use of spunlace nonwoven requirements,the project chose to use 100%bleached chemical coniferous wood pulp as the raw material for the production of wood pulp raw paper.
2、The main process flow of spunlace nonwoven fabric
3、Technical conditions of production process
3.1 Pulp proportioning
Adopt 100%bleached sulfate coniferous wood pulp(index:brightness 88%-90%,dustiness not more than 25mm2/kg,fiber length not less than 2.0mm,raw pulp pulping degree 13-15OSR).
3.2 Pulping process
In order to make the fiber fully dissociated,adopt the intermittent pulping method of low concentration hydraulic pulper,the pulping concentration is controlled to 3.5%-4.0%,the pulping time is not less than 20min per tank,and the pulping material after pulping is fed into the pre-knock pulp pool for grinding.
3.3 Grinding process
Pulping process requirements are shown in Table 1.with the increase in pulping degree,although the longitudinal and transverse dry and wet tensile strength are improved,but with the paper tightness and stretch rate is increasing,water absorption,
dimensional stability are declining trend.The fiber analyzer detects the gradual increase in fine fibers,paper processing,fine fibers are easy to fall off,resulting in fiber chips,is not conducive to the later spunlace composite and use.
Therefore,in order to meet the longitudinal and horizontal dry and wet strength of the paper,the normal production conditions of the paper machine,the degree of pulping as much as possible to reduce some.Production in practice,the degree of pulp control in 28-30°SR.
3.4 paper machine main production process parameters
In order to ensure uniform distribution of paper fibers,the sizing system using hydraulic flow box,shaking device for the German reaction force-free high-frequency shaking machine,
shaking energy requirements of not less than 6000,the production process requires the lowest possible online concentration;to ensure that the paper aspect strength ratio control within 1.3,the pulp network speed ratio control set to 0.96-0.98.Production of the actual speed of 320m/min,online concentration 0.15%-0.2%,frequency 400-450 times/min,amplitude 12-15mm.
3.5 Chemical use
Add chitosan fungicide 0.10-0.12 kg/t paper in the pulp dispensing pool,without using any other chemical additives.
4、Influence factors and measures of raw paper falling hair
Grinding influence:In the pulping process,the fiber splitting broom rate gradually increases,and the fine fibers are gradually increased by the fiber analyzer.Paper processing fine fibers easy to fall off,resulting in hair phenomenon,
is not conducive to the later spun composite and use.Therefore,in the production of good control of the pulp degree,the actual production of the pulp degree control at 28-30°SR.
Paper blanket impact:the choice of press blanket depends on the variety of paper produced,quantitative and surface finishing requirements,
spunlace nonwoven raw paper requires a high surface fineness,uniform consistency,so blanket selection should give priority to the blanket surface fineness,the actual use of the requirements of the wool network and blanket ratio of not less than 65%,
while the surface fiber weight and wool network ratio should not be less than 30%,and the surface fiber fineness straight through It is required that the ratio of wool net to wool blanket should not be less than 65%,and the ratio of fiber weight to wool net of surface layer should not be less than 30%,
and the straightness of surface fiber should not be more than 8dtex.At present,the domestic wool blanket can meet the requirements in all aspects,but the surface fineness is not enough,and the phenomenon of pulp entanglement often occurs.
At present,we use Italian imported felts to solve the problems caused by the lack of fineness of domestic felts.At the same time,the blanket should be cleaned with high efficiency net blanket cleaning agent during production to keep the blanket clean fully.When the blanket in the press section is not selected properly or used for too long a period,
the late local dehydration capacity is insufficient and the elasticity is poor,it will lead to inconsistent paper surface finishing and the blanket should be replaced regularly.