Study On Synthesis And Properties Of A New Type Of Pure Acrylic Emulsion Composite Adhesive

With the rapid development of tobacco industry in China,the requirements for tobacco glue are getting higher and higher.The compound glue used in the production of aluminized silver cardboard is also developing continuously,and its performance and environmental protection requirements are getting higher and higher.Acrylate emulsion adhesive is a kind of adhesive widely used in packaging industry.It has the advantages of good weather resistance,transparent film,low viscosity,easy coating and suitable for continuous production line operation.In this paper,a kind of waterborne pure acrylic emulsion composite adhesive was prepared by pre-emulsification semi-continuous seed emulsion polymerization.First,butyl acrylate(BA)is the soft monomer,methyl methacrylate(MMA)is the hard monomer,and acrylic acid(AA),diethylene glycol diacrylate(DEGDA)and hydroxyethyl acrylate(HEA)are the functional monomers.The suitable anionic/non-ionic composite emulsifier is sulfosuccinate alkyl alcohol ether ester sodium salt/secondary alcohol polyoxyethylene ether(A102K/S90).The system does not contain alkyl phenol polyoxyethylene ether compounds(APEO),which is an environmentally friendly emulsifier.Initiator,p H buffer,defoaming agent and other auxiliaries are also determined.Secondly,the pure acrylic emulsion polymerization experiment was carried out in a2000 m L reactor.The effects of monomer ratio and dosage,polymerization reaction temperature,reaction time,the dosage of defoaming agent,initiator,p H buffer and stirring rate on the emulsion properties were investigated.The experimental results showed that when m(BA):m(MMA)=2:1,the dosage was 89 wt%;m(AA):m(HEA)=2:3,the dosage was 5 wt%;the dosage of DEGDA was 6 wt%,the dosage of initiator,p H buffer and defoaming agent were 0.5 wt%,1.8 wt% and 0.7 wt% respectively,the stirring rate was 150 rpm,the reaction temperature was 75 ℃,the reaction time and holding time were 5.5 h and 1.0 h,respectively.The synthetic pure acrylic emulsion composite adhesive had good comprehensive properties.In the process of further optimization of polymerization process and experimental formula,emphasis was placed on the optimization of initiator drop distribution,the distribution of composite emulsifier solution and the ratio of hard and soft monomer.After optimization,on the basis of the original formula and process,the mass ratio of soft and hard monomers was optimized to 1.2:1 with other conditions unchanged.The total amount of initiator remained unchanged,and two batches were added according to 4:1.The dosage of the compound emulsifier in the preemulsion and the base solution was 1:4.When the solid content is 45.94%,the emulsion p H is 6.0,the viscosity is 902 m Pa·s,the average particle size is 259.6 nm,the peel strength is 307.24 N/m,and the centrifugal stability is good.Under laboratory conditions,the surface gloss of the aluminized silver cardboard is high,the bending is more than 20 times,and the aluminum layer on the surface of the cardboard does not break and fall off.Finally,the scaled-up experiment of pure acrylic emulsion synthesis was carried out in a50 L jacketed stirred reactor.It can completely peel off the aluminized layer on the PET film and transfer it to the cardboard,basically meeting the continuous production of aluminized silver cardboard.The amplified synthetic emulsion was characterized by rotational rheometer,DSC,FT-IR,TEM and SEM.The results show that the synthesized emulsion is acrylate polymer,the latex particles are spherical,the average particle size is about 250 nm,the particle size distribution is uniform,the polymer Tg is 4.0 ℃.The rheological property curve shows that the viscosity of emulsion is stable at higher shear rate.