单体组成对苯丙乳液及纸塑复膜胶性能的影响_英文_

Recived data :2008206203Aut hor vita :ZHAN G Kai (1979-),female ,f rom Huanggang of Hubei province ,a doctoral student of South China Universi 2ty of Technology and a lecturer of Huanggang Normal University ,majoring in waterborne adhesive.Effect of Monomer Comp osition on Perf or ma nce of St yrene Acrylate Emulsiona nd Paper 2plastic L a minated AdhesiveZ H A N G Kai1,2,S H EN H ui 2f ang 1,FU He 2qi ng 1,GUO W en 2j ie 1,L A N Ren 2hua 1,C H EN H uan 2qi n1(1.South China University of Technology ,Guangzhou 510640,China ;2.Huanggang Normal University ,Huanggang 438000,China )Abstract :A kind of paper 2plastic laminated adhesive based on styrene acrylate emulsion was preparedby emulsion polymerization.The monomers chosen were butyl acrylate ,22ethyl hexyl acrylate ,styrene ,and methyl methacrylate ,along with a small amount of methacrylic acid.Effects of monomer composition on the properties of styrene acrylate emulsion and laminated adhesive such as monomer conversion ,floc 2cules weigh and peel strength were investigated.The results showed that when the content of methyl meth 2acrylate ,22ethyl hexyl acrylate ,and methacrylic acid was 10%(mass f raction ,the same after ),8%,and 2%-5%(based on total monomer charge ),respectively ,and the weight ratio of soft monomer to hard monomer was in the range of 1.5:1to 2.5:1,the optimal styrene acrylate emulsion could be prepared.The styrene acrylate emulsion can be used on lamination adhesive for BOPP\PET film to printed paper ,and the peel strength (180°)can be reached 7.75N /2.5cm (PET film to paper ).Key words :monomer composition ;styrene acrylate emulsion ;paper 2plastic laminated adhesive CL C number :TQ433　Document code :A Article ID :1001-3563(2008)09-0034-04 Paper 2plastic ,a technology combining BOPP\PET film and printed paper with adhesive ,can improve the ap 2plication performance and appearance of the presswork ,and is widely used in packaging industry.At present ,solventborne adhesive has been used for most of the package industry in our country.However ,growing environmental and legislativepressures has been inspiring the search for safer alternative ,waterborne adhesive offers a safer alternative [1].For example ,acrylate emulsion currently has the biggest share of the water 2borne adhesive market[2].Styrene (S )readily copolymerizeswith most acrylate monomers ,an important class of emulsion polymers known as styrene acrylate polymers exists ,where S is copolymerized with other acrylate monomers [3].Compared with acrylate emulsion ,styrene acrylate emulsion has similar performance ,but its cost is low ,so that it is popular in many areas.The paper 2plastic laminated adhesive obtained f rom sty 2rene acrylate emulsion possess good properties ,including ex 2cellent adhesion and good quality of film covering ,simple pro 2duction technology and low cost [4-5].The performance of pa 2per 2plastic laminated adhesive obtained f rom styrene acrylate e 2mulsion depends on many factors ,such as polymerizationmethod ,monomer compostion ,emulsifier and so on [6].A 2mong these ,monomer composition is the most important factor influencing on the performance of the adhesive.The objective of the present study was to examine the influences of monomer composition on the properties of emulsion and the adhesive ,and to prepare styrene acrylate emulsion for paper 2plastic lami 2nated adhesive with good proformance.1　Experiment al1.1　MaterialsMonomers butyl acrylate (BA ),styrene (S ),methyl methacrylate (MMA ),22ethylhexyl acrylate (22EHA )and methacrylic acid (MAA ),emulsifier Triton X 2405and sodium dodecyl sulfate (SDS ),ammonia solution (ammonia ,25%)were all industrial grade obtained from Guangdong Carpoly Co.L td.(Jiangmen ,China ).Initiator potassium persulfate (KPS )and sodium hydrogen carbonate (Na HCO 3)were of analytical grade and purchased f rom Guangzhou Chemicals Factory (Guangzhou ,China ).Deionized water was prepared by my 2self.Plastic films (OPP ,PET )were provided by ZhejiangHuangyan Hua2guang Resin Chemical Factory.1.2　Synt hesis of styrene acrylate emulsion and p rep ared ofp aper2plastic laminated a dhesiveThe styrene acrylate emulsion used in this study was pre2 pared by using a starved feed,semibatch emulsion polymeriza2 tion technique.The weight percent solids content of the sty2 rene acrylate emulsion was designed to be50%.The styrene acrylate emulsion was prepared in a1-L,glass flask,fitted with a stirrer,water2cooled condenser,nitrogen bleed,ther2 mocouple and feed vessels.Deionized water and sodium hydro2 gen carbonate were charged to the flask and heated to80℃.A few minutes prior to commencement of the monomer,certain initiator solution was added once to the flask,then certain monomer pre2emulsion(10%charge of the total monomer pre2 emulsion)was fed at constant rate into the flask over15mi2 nutes,and keep reaction temperature at80℃for15minutes. Then the surplus monomer pre2emulsion and initiator solutions were fed to the flask at constant rate over a4h period.During the4h of feeding,the reaction temperature was controlled at 80℃.After feeding is over,the reaction temperature was also maintained at80℃for30minutes,and then heated to86℃to react st,the reaction mixture was cooled to room temperature.The p H value of the emulsion was adjusted to7 -7.5with aqueous ammonia solution.The wetting agent was added into the styrene acrylate e2 mulsion,and paper2plastic laminated adhesive was made.Then the adhesive was coated onto the surface of the paper/B OPP film and paper/PET film respectively.The paper2plastic films were dried at50°C for2h.1.3　TestingThe monomer conversion and floccules weigh of the emul2 sion were measured by gravimetry.The peel strength was test2 ed according to G B/T2791-1995at a crosshead speed of4 mm/min.The testing machine is PC Auto Tensile Tester Ma2 chine(Jinan Labthink Instruments Co.,Ltd).The values ob2 tained were the average of five replicates.2　Res ults a nd disscussion2.1　Effect of monomer type on t he p roperties of emulsion a ndadhesiveBA and22EHA,as homopolymers or copolymers,provide tacky,dried polymer films with low glass transition tempera2 tures(T g).However,their poor resistance to shear and low room temperature peel resistance restrict their usef ulness as polymers for adhesive.To improve their room temperature performance,it is necessary to raise their T g.Raising the pol2 ymer T g is achieved by copolymerization with hard monomers, such as MMA and S.In addition,some monomer such as MAA can be added to provide sites for cross2linking reactions or to improve latex colloidal stability.The inclusion of MAA can also lead to enhanced adhesion.Therefore,BA and22 EHA,S and MMA,and MAA were chosen as soft monomers, hard monomers,and f unctional monomer respectively in the styrene acrylate formulation.In the experiment,the effect of monomer type on the properties of emulsion and adhesive was examined(Shown in Table1).The results showed that a certain amount of22ethyl2 hexyl acrylate was introduced into the composition,the film of the emulsion turned to be more softer,it is usef ul for covering film,and the peel strength of the adhesive was improved. When the hard monomer component contained styrene only, the monomer conversion was low,and some monomers was re2 mained in the emulsion after the polymerization was over.It was found that when addition of10%(based on total monomer charge)methyl methacrylate in the formulation,the monomer conversion can be reach98.3%.Tab.1Effects of monomer type on t he propertiesof emulsion a nd a dhesive表1　单体种类对乳液及胶粘剂性能的影响Sample A-1A-2A-4 Soft monomer BA BA+2-EHA BA+2-EHAHard monomer St St MMA+St Emulsion appearanceMilky andslightly bluishMilky andslightly bluishMilky andbluish Monomer conversion/%92.189.598.3180°peel strength(paperto BOPP)/(N・(2.5cm)21)1.14 1.252.51180°peel strength(paperto PET)/(N・(2.5cm)21)4.01 4.757.752.2　Effect of t he weight ratio of soft monomer to hard mono2mer on t he p roperties of emulsion and a dhesiveButyl acrylate and22ethylhexyl acrylate,styrene and methyl methacrylate were chosen as soft monomers and hard monomers respectively.Under all the other parameters kept constant,and MMA was fixed at a level of10%.The effect of the weight ratio of soft monomer to hard monomer on the prop2 erties of emulsion and adhesive was examined(Shown in Table 2).Tab.2Effects of weight ratio of soft monomer to hard monomer on t he properties of emulsion a nd adhesive表2　软/硬单体质量比对乳液及胶粘剂性能的影响Sample B-1B-2B-3B-4B-5 Weight ratio of soft mono2mer to hard monomer1∶1 1.5∶12∶1 2.5∶13∶1Emulsion appearanceMilky andslightly bluishMilky andbluishMilky andbluishMilky andbluishMilky andslightly bluish180°peel strength(paperto BOPP)/(N・(2.5cm)-1)2.8 2.64 2.51 2.45 1.76 180°peel strength(paperto PET)/(N・(2.5cm)-1)8.257.97.757.63 6.75The results showed that when the weight ratio of soft monomer to hard monomer is closed to1∶1,the Tg of the co2 polymer is above0℃,there is much hoar frost on the plastic film,although the180degree peel strength is strong.When the weight ratio of soft monomer to hard monomer is closed to 2∶1,the Tg of the copolymer is about0℃,the covered film has good quality,and there didn’t exist the missing area of ad2 hesive and hoar f rost on the plastic film.When the weight ratio of soft monomer to hard monomer is above3∶1,the180de2 gree peel strength turned to decrease.It can be explained that when the content of hard monomer is high,the latex is difficult to melt and wet the substrate,so the quality of film covering is bad.When the content of soft monomer is too high,the Tg of the copolymer is too low,the adhesive shows flow regime in the room temperature,although it can sufficiently wet the sub2 strate,the cohesive strength of the adhesive is weak.Consid2 ered the adhesive properties on wettability and cohesive strength,the optimal weight ratio of soft monomer to hard monomer is in the range of1.5∶1to2.5∶1.2.3　Effect of22EHA content on t he p roperties of emulsiona nd adhesiveIn the experiment,it was found that22EHA can improve the adhesive greatly.Under all the other parameters was fixed, the effect of the22EHA content(based on total monomer charge)on the properties of emulsion and adhesive was exam2 ined(Shown in Table3).From the table,it can be seen thatTab.3Effects of22EHA contenton t he properties of emulsion a nd adhesive表3　22EHA含量对乳液及胶粘剂性能的影响Sample C-1C-2C-3C-4C-5 22EHA content/% 2.0 4.0 6.08.010.0Emulsion appearance M ilky andbluishM ilky andbluishM ilky andbluishM ilky andbluishM ilky andslightly bluish180°peel strength(paperto BOPP)/(N・(2.5cm)-1)1.802.05 2.23 2.51 1.96180°peel strength(paper toPET)/(N・(2.5cm)-1)5.25 5.84 6.517.757.04the180degree peel strength of the adhesive was first increasedwith the increase of the22EHA content,and then reduced Theoptimal content of22ethyl hexyl acrylate is8%.2.4　Effect of MAA on t he p roperties of emulsion a nd a dhesiveUnder all the other parameters was fixed,the effect ofMAA content on the properties of emulsion and adhesive wasexamined(Shown in Table4).It can be seen that with the in2crease of MAA,the floccules weight is decreased.This may bedue to the carboxyls was attached to the branch chain of the co2polymer when MAA was added,and it trended to distributethe surface of latex,by which can inhibit the formation of floc2cule.At the meantime,when the amount of MAA was in2creased,the degree of cross linking was increased,the180de2gree peel strength of adhesive was improved.However,whenthe content of MAA exceeded5%,the viscosity of the emul2sion is rather high,which caused the pourability of emulsion toturn bad.What’s more,f urther increase of MAA content re2sulted in a decrease of the peel strength of the adhesive.There2fore the optimal amount of MAA in our system is in the rangeof2to5%.Tab.4Effects of MAA contenton t he properties of emulsion and a dhesive表4　MAA含量对乳液及胶粘剂性能的影响MAAcontent/%Floccules weight,g/kg emulsion180°peel strength(paper to BOPP)/(N・(2.5cm)-1)180°peel strength(paper to PET)/(N・(2.5cm)-1)1 2.6 2.25 6.862 1.8 2.517.753 1.7 2.627.884 1.6 2.688.015 1.5 2.547.86 1.5 2.197.253　ConclusionsA kind of paper2plastic laminated adhesive was preparedusing styrene acrylate emulsion.The monomers chosen werebutyl acrylate,22ethylhexyl acrylate,styrene,and methylmethacrylate,along with a small amount of methacrylic acid.The effect of monomer composition on the properties of the e2mulsion and adhesive was investigated,and the following con2clusions were obtained:1)Adding10%of methyl methacrylate in the formula2tion,the monomer conversion can be reached98.3%.The op2timal weight ratio of soft monomer to hard monome is in therange of1.5∶1to2.5∶1,the optimal content of22ethyl hex2yl acrylate is8%,and the optimal amount of methacrylic acidis in the range of2to5%.2)The optimal emulsion can be used on lamination adhesive for BOPP\PET film to printed paper,and the peeling strength (180°)can be reached7.75N/2.5cm(PET film to paper).References:[1]　L I Ling2feng,YE Chu2ping,ZHAN G Zheng2hua.Packing Ad2hesive and Adhesion Technology[M].Beijing:Chemical Indus2 try Press,2005.[2]　J OVANOVIC Renata,OU ZIN EB Keltoum,MCKENNA Timo2t hy F,et al.Butyl Acrylate/Met hyl Met hacrylate Latexes:Ad2 hesive Properties[J].Macromol Symp,2004,206:43-56. [3]　GOWER Mark D,SHAN KS Robert parison of Styrenewit h Met hyl Met hacrylate Copolymers on t he Adhesive Perform2 ance and Peeling Master Curves of Acrylate Pressure Sensitive Adhesives[J].Macromol Chem Phys,2005,206:1015-1027.[4]　CH EN Yuan2wu.An Emulsion Adhesive for Lamination of Alu2minum2plated Laser Film and White Mirror2faced Cardpaper[J].China Adhesives,2006,14(6):22-24.[5]　CH EN Yuan2wu.Study on t he Emulsion Paper2plastics Lamina2tion Adhesive of Environmental Friendly Type[J].China Adhe2 sives,2006,15(4):31-33.[6]　L I J un,WAN G Rui2ming,DEN G Shi2ying,et al.The Study ofWater Emulsion Paper/plastic Laminating Adhesive[J].Chem Tech,2005,27(5):26-29.单体组成对苯丙乳液及纸塑复膜胶性能的影响张凯1,2,沈慧芳1,傅和青1,郭文杰1,蓝仁华1,陈焕钦1(1.华南理工大学,广州510640;2.黄冈师范学院,黄冈438000)摘要:以丙烯酸丁酯、苯乙烯等为主要单体,采用乳液聚合法制备了苯丙乳液纸塑复膜胶。