The friction factor of solvent-free composite products, a comprehensive improvement!

【 What to watch for 】 Zhongshan torch vocational and technical college personnel in order to study the change of the friction factor, solvent-free composite products conducted an experiment. Experimental materials for: WD8118A/B universal bi-component solvent free film adhesive, heat sealing film, PE normal blank roll of film. The experimental results are as follows. Solvent-free composite products for the influence of the friction factor of 1, heat sealing film thickness on the influence of friction factor of solvent-free composite product heat sealing layer surface friction factor rise because of the heat sealing layer of smooth agent under high temperature, some happening to heat sealing film laminating adhesive level & other; Inland & throughout; , and the isocyanate solventless adhesives base reaction. PE heat sealing film often USES the three layers co-extrusion structure ( A / B / C) , A layer for the compound near the surface, B layer for the middle tier, as close to the packaging object C layer. Usually only add smooth agent in C layer, smooth agent or need to pass A and B layer, therefore, in the process of moving, smooth agent to glue layer resistance, the greater the migrated to the less glue layer smooth agent, reaction with the glue the less smooth agent, the less the increase of friction factor. Using C layer thickness is the same but the total thickness of 46 respectively (microns of PE three-layer coextrusion heat sealing film, as shown in figure 1, PE in a composite heat sealing membrane before and after the composite dynamic/static friction factor are trending up, before and after the composite, the thickness of the dynamic/static friction factor of 46 mu m up 41 respectively. 9% and 34. 4%, 37 microns thickness for the dynamic/static friction factor of up to 55, respectively. 6% and 53. 6%, so add A layer or B layer thickness can slow the rate of climb of friction factor. Found in the actual production, the film thickness is less than 30 microns, the change of the friction factor is too big, not suitable for production requirement, suggest that film thickness over 35 microns. 2, heat sealing layer with different structure to the friction factor of the influence of different manufacturers of heat sealing membrane effect on friction factor vary widely, in addition to related to the thickness of heat sealing film, also related to the structure of the heat sealing layer. Adoption of 46 microns thickness for two different structure of heat sealing film, PE A three layer structure (heat sealing membrane The outer/middle/heat sealing layer) The formulation are: linear low density polyethylene ( LLDPE，50%） + low density polyethylene ( LDPE，50%） / linear low density polyethylene ( LLDPE，100%） / linear low density polyethylene ( LLDPE，35%） + low density polyethylene ( LDPE，30%） + metallocene polyethylene ( 迈普30%) + smooth masterbatch ( 5%) , the thickness of each layer of 15,15,16 mu m respectively. 3 B heat sealing membrane layer of the structure of the formula for LLDPE ( 50%) + LDPE（ 50%) / LLDPE（ 70%) + recycling material ( Contain MDPE, 30%) /LLDPE（ 35%) +LDPE（ 30%) +MPE（ 30%) + smooth masterbatch ( 5%) , the thickness of each layer of 15,15,16 mu m respectively. From figure 2, the containing medium density polyethylene ( MDPE) The friction factor of recycled material is lower than without adding recycling material, this is mainly related to high relative crystallinity MDPE recycling of material, part of the inner inland smooth agent is prevented, may also with MDPE recycling material itself contains a certain amount of smooth agent. Thus, while the production of PE film for formula design, add a certain proportion in the outer layer or layer material MDPE, can to a certain extent, prevent the migration of smooth agent, thereby reducing the friction factor of rising sharply. 3, the influence of the curing process of friction factor curing process control including curing temperature and curing time, temperature affects the migration of smooth agent speed and the compatibility of PE film for smooth agent, reaction speed and adhesive and smooth agent. Can be seen from the figure 3, 30 ℃ when the friction factor of PE film than 23 ℃ increased, this is because the temperature rise will increase the compatibility of PE film for smooth agent, prompting a smooth agent to PE film & other; Inland & throughout; , smooth agent mobility increases, and increases with the reaction of isocyanate group. In addition, may also be smooth agent with low melting point, when the temperature increase in the role of adhesion and lose a smooth. In the process of curing, the friction factor in 24 h after curing peak, with cure completely, friction coefficient decline gradually, this may be related to outsourcing of completely after curing at room temperature is placed a smooth agent, because amine migration patterns of smooth agent is moving in high temperature conditions, and in the low temperature of 12 cases. Measures to improve the friction factor 1, heat sealing film smooth agent formula improvement after solvent-free composite, solvent-free composite products increased friction factor is the root cause of PE smooth agent of oleic acid amide and erucic acid amide reaction with the NCO in solventless adhesives, so use the smooth agent such as esters alternative oleic acid amide and erucic acid amide, can fundamentally solve the friction factor. In addition, in the design of smooth agent formula, smooth agent and the compatibility of PE resin, health resistance, temperature tolerance, the processing eligibility and the efficiency of the friction factor and so on, is to solve the key technology of solvent-free composite friction factor to rise. 2, heat sealing film of technological formula improvement based on the analysis of figure 2, USES the PE with good barrier property to prevent part of the migration of smooth agent. The present approach is layer (near the adhesives The outer layer) Co-extrusion layer of HDPE, HDPE high crystallinity and tensile strength, but the tensile rate and transparency without LDPE, LLDPE resin such as well, in the aspect of application.