TAP CHI HOA H(PC T. 52(1) 8-13 THANG 2 NAM 2014
NGHIEN c d u QUA TRINH LAM NHANH KHO M A N G MUG IN ^ NHU TUONG NUdc TRONG DAU B A N G XUC TAG PHUG [Go(Acac)]
Le Van Huynh
Truang Dgi hqc Kinh ti - Ky thudt Cong nghiep Din Tda soan 4-5-2013
Fast growing digital printers are widely used in all areas, by the superiority of them are: To meet flie on time, high yield, quality guarantee and low cost. Ink for digital quick pnnters ink is water-in-oil emulsion, the need to have time to dry the ink fihn must fast during the printtng process, so as not to affect the quality of the next printed sheet, to increase in output, requires ink film to dry quickly. To solve problems using complex catalyst. This paper is the application of research results catalyzed con:q)lex created by Co^* with Axetylaxeton (Acac), the membrane during fast drying water- in-oil emulsion ink, used for digital quick printers. Putting catalytic con^lex [Co(Aeac)]^ in water-in-oil emulsion ink, reduced diying time of the ink film fi-om 223s to 65s, which was 4 times increase in output. Research resuhs is the scientific basis for the application of complex catalyhc applications in practical production process.
Keyword: Ink emulsion.
I.MQDAU
May in nhanh ky thu^t so ngay eang duge su dung rpng rai ttong mgi ITnh vyc, bdi tfnh uu viet eiia chung do la: Dap iing dugc ve mat thdi gian, san lugng ldn, chat lugng dam bao va cd gia thanh hgp ly, phil hgp vdi da sd ngudi tieu diing. Myc diing cho cac loai may in nhanh ky thuat sd la myc in nhu tuang nudc trong dau, can phai co thdi gian khd mang mue phai nhanh ttong qua trinh in, de khong gay anh hudng tdi chat lugng td in tiip theo, muln tang san lupng in, doi hdi mang myc in phai kho nhanh, cd nhu vay mdi cd the tang san lugng in len duge. Do do viSc bo sung chit Iam nhanh kho mang myc in, co tae dung thiie day, rut ngan thdi gian nhanh kho mang myc tten vat lieu in.
Muc tieu ciia viee nghien cuu la tiio ra mot loai mye eo tinh In djnh nhO tuang cao, ed thdi gian sd dung dai, khi in tao ra nhiJng hinh anh cd kha nang chong nhoe tdt va ehat lugng hinh anh tot theo thdi gian dudi tac dgng cua dieu kien mdi trudng nhu nhiet do, anh sang... Myc in nhu tuang nudc trong dau can c6 do nhdt tuong ddi thap nao do nhung van cho cac gia tti mau cao va co tinh nang in tot. Chat hoat dgng be mat, chat lam nhanh kho mang myc cd tac dung de kieh hoat va dn dinh nhu tuang, lam giam sue eang bl mat cua phin dau, tang tdc dp mau khd cua mang myc. Chat lam dae cho myc, cd do truang nd rat ldn trong mdi trudng eo nudc, co tac dyng khau maeh tao ra dang gel ciia myc, lam dn
djnh nhii tuang va lam cho myc cd do nhdt dn djnh.
Phuang phap su dung xiic tac phuc ddng the oxi hoa khu co hieu qua trong qua trinh lam nhanh kho mang myc in, phuc xiic tac dugc sd dung la phire tao bdi ion kim loai Co^"^ vdi Axetylaxeton (Acac) eo kha nang boat hoa O2 phan tix ttong khdng khi, thanh oxi nguyen tu O* de trung hop cac phan tii- diu khdng no cd ttong thanh phan cua myc in, rut ngan dang ke thdi gian mau kh6 ciia mang myc trSn vat lieu in ttong qua trinh in, day cOng la diim mdi cua cong ttinh nghien cuu.
Bai bao nay la ket qua nghien cuu ung dung xue tac phuc tao bdi Co^* vdi Axetylaxeton (Acac), vao ttong qua trinh lam nhanh khd mang myc in nhii tucmg nudc trong diu, dung cho cac loai may in nhanh ky thulit sd. Dua xuc tac phdc [Co(Acae)]*
vao myc in nhu tuang nudc trong dau, da giam thdi gian nhanh kho ciia mang myc tten vat lieu in trong qua trinh in, tir dd da tang dang ke san lugng in len gap nhilu lin.
Ket qua nghien cuu la eg sd khoa hge cho viec ung dyng xiic tac phuc vao thyc tiin cac qua trinh san xuat.
2.THU'CNGHI$M
2.1. Che tao chat Iam nhanh kho mang mirc in Chat lam nhanh khd mang myc in dugc sd dung la phuc xuc tac tao bdi Co^* vdi Axetylaxeton
TCHH.T. 52(1), 2014
(Acac). Cac hoa chit dugc sii dyng cd dg sach PA, nudc cat 2 Ian. Cac dung djch dl tao phuc xiic tac gom dung djch C0SO4 va dung djch Axetylaxeton (Acac). Hdn hgqi myc va chit lam nhanh khd [Co(Acac)]'*' va cac thanh phan cua myc nhu tuang dugc khuay ttdn de tao cho myc cd dang gel d dieu kien nhiet do va ap suit thudng.
Axetylaxeton CsHg02 la chat Idng khdng mau hoac hai vang nhat, cd M = 100,12 g/mol; Khdi lugng rieng la 0,9721 g/cra^ d 25 °C, do Mng Merck ciia CHLB Dxxc san xuat. Acac eo kha nang tiio phdc vdi cac ion kim loai chuyen tiep nhu: Co^*, Fe^*, Mn^*, Ni^^.... Nhom metylen d giiia 2 nh6m cacbonyl co do linh ddng rat cao. Trong dung djch khi d pH cao Acac d dang enol hda de dang tach proton, ra khoi nhom OH, cap dien td khdng ehia ciia oxi ttong nhdm CO" dien vao orbital d^sp^ ciia Co^'^, dong thai c^p dien tu cua oxi trong nhom C = O cua Acac tao lien k6t phdi tri thd 2 vdi ion Co^*
tao thanh phuc co hoat tinh xuc tac.
Axetylaxeton tdn tai d 2 dang theo can bai^:
dang cacbonyl va dang enol. Trong mdi trudng kiem d nhi?t d$ 25 °C Acac tin tai can bang vdi PKA = 9,375 [1,2].
CH3-C - CH; - C - C H 3 < •
II II
O O Dang cacbonyl CH3 - C = CH - C - CH3
I II
HO O Dang enol
Q dieu kien thudng Acac cd chda 76,4% dang cis-enol va 23,6% dang xeton. Q dang enol nguyen tir hydro ttong eis-enol tham gia phan utig tao phdc vdi nhieu kim loai.
C H j - C - CHj - C - C H 3 - ^ O O CH3 ^ C - CH = C - CH3 + H*
II I
O O"
Djc diim ciia myc in nhu tuang nudc trong dau gom 2 pha: Pha dau va Pha nudc.:'
Pha diu: Chua chat mau, nhya, chit boat ddng be m$t, chit tao mang va dau lien ket. Dau ttong thanh phan ciia myc in nhu tuong, thudng la cac loai dau nhanh kho, con cac chit mau thudng d dang pigment ua diu. Pha dau la moi trudng phan tan chiem khoang 25-30 % gom cac chit tjio m^u, diu lien ket vi cac chit phy gia nham dieu chinh cac tinh chat khac nhau ciia myc in nhu dg nhdt, dO dinh, dg
Le Vdn Huynh chajf, ket dinh,.... Cac loai diu lien kit thudng dung la dau lanh, tinh chat cua diu lanh trong myc in nhu tuang phy thupc vao vj tri ndi ddi va sd nguyen tu cacbon ttong phan tu cac axit khong no nhu: axit linolenic C17H29COOH, axit linolic CijHaiCOOH va axit oleic CiyHjjCOGH, axit ricinoleic HO-C17H32- COOH. Dudi tac dyng ciia xuc tac phiirc, cac axit beo khdng no nay sau khi in tten giay, de dang ket hgp vdi oxi O2 khong khi sau khi dugc boat hoa theo phan ung trung hgp, tao cho mang myc kho nhanh d6 bao ve chat mau ttong myc in [I, 2,4, 6].
Pha nudc: La pha phan tan chiem khoang 65-70
% chu yeu la nudc va cac chat hoa tan ttong nudc.
Vai tto chu yiu ciia nudc la chdng hien tirgng sa ling va ket ludi ttong qua ttinh in, tang kha nang phan tan cua chat mau va dau lien ket.
Mye nhu tuang nudc trong diu co nhieu uu diem phu hgp vdi phuang phap in ciia cac may in nhanh ky thu|t sd, cd cudng do mau cao, cac pigment dugc phan tan trong pha nude, ttong qua trinh in tao ra ldp mang myc cd do bdng dep, thdi gian kho nhanh, khi kho mang mye ben chac, eho phep tang toe dg in. Dieu dac biet la ta cd the dieu chinh dugc do nhdt, do dinh ciia mye sao cho phii hgp vdi phuang phap in la tuong ddi de dang do sy cd mat cua pha nudc.
Dp nhdt va dg dinh cua myc in nhii tuong ciing la nhimg yeu td anh hudng din tinh nhanh kho cua mang myc in tren vat lieu in. Dp nhdt ciia myc phy thugc nhieu vao tinh chat va ham lugng nhya sd dyng, can phai cd mdt lugng nhya tdi thieu de dam bao cho pigment phan tan tot va h^ nhu tuang ciia mye cd do on dinh cao. Do dd myc nhu tuong dugc coi la If tudng niu c6 duge dg nhdt tuang doi thap, ttong khi van dam bao dugc dg on djnh cao, kha nang tao mang tot, cung nhu cudng dp mau cao, ddng thdi dp nhdt ciia myc nhii tuang cung la mgt trong nhirng yeu t l anh hudng din dp day mdng ciia mang myc khi in tten nhirng vat li$u in cd dg thim hiit khac nhau, lien quan chat che tdi tinh dinh, tinh chay cua myc, lam cho qua trinh in tot han, chong dugc hien tugng ket ludi cua trdng in ciia mdy in nhanh ky thuat s6.
2.2. Ca che hoat hoa ciia xuc tac phirc Sy kho cua mang myc tten vat li?u in phu thugc vao cac thanh phin ciu thanh ciia myc, tinh thim hut cua giiy, dg day mdng ciia mang myc, dg cao ciia chdng giiy va dieu kien mdi trudng. Khi dimg myc in nhu tuong nudc ttong diu thudng diing d dieu kien nhi^t dp va ap suat thuong, nen khong can phai gia nhiet trong qua trinh in. Sy kho ciia mang myc in dien ra theo hai qua trinh khd vat ly va khd hoa hgc [6, 7].
TCHH, T. 52(1), 2014 Nghien cuu qud tnnh lam nhanh Icho...
Sy khd vat ly la |di6 do tham hiit va bay hai Sy khd hoa hgc la qua trinh kho va ddng ran ngay sau khi myc truyen sang giay la bit diu diln ra mang myc in, khi hip thy oxi dudi tac dung ciia xiic sy khd tham but cua myc vao giay, nghTa la giay se tac phuc [Co(Acac)]* diln ra rit phuc tap qua nhieu hap phu cac phan tu dung mdi va cac phan tii dau giai doan [1, 3, 6, 7].
nhya. Tai day xuat hien sy khd be mat, sy hap phu Giai doan t^o th^nh Peroxit
thong qua cac mao quan cua giiy, giira cac sgi Dudi tac dung ciia xuc tac phiic [Co(Acac)]^ oxi xenlulo CO nhirng khe Id ttong, tao dieu kien thuan phan tii O2 bj boat hoa, phan cat thanh oxi nguyen tu lgi cho s\i tham hut va sy kho bl meit mang myc in. O*. Cac nguyen td oxi nay tham nhap vao cac lien Giay c6 nhieu mao quan hep va nhd tten b l mat, sy kit ddi cua cac phan tu diu khdng no cd ttong thanh tham hut nhanh, nen sy khd bl mat dien ra nhanh phin ciia myc in nhu tuang, t^io thanh cac gdc ty do han. Tren bl m|it giay, nhihig thanh phan phan td RO* cd kha nang phan ling triing hgp vdi nh&ng dung mdi va phan tu dau nhya thap cua myc giam phan tu dau khdng no cd ndi ddi ben canh, tao thanh di, nhiing thanh phan khac ciia myc in cdn lai tten be mang polyme che phii be mat mang mye tren vat mat giay kho va ran Iai, tao nen sy khd be m§t mang lieu in, t?io nen sy ddng ran mang myc in nhu:
myc in [I, 2,4, 5].
Axit Ricinoleic: HO-CnHjj-COOH.
Cong thirc ciu tao: HOOC-(CH2)7-CH=CH(OH)-CH2-CH-(CH2)r-CH3 Axitalpha-Iinolenic(a-cis-octadeca-9,12,I5-tt^enoicacid)C|7H29COOH Cdng thiie ciu tao: H3C-(CH2-CH=CH)3-(CH2)r-COOH
Dudi tac dyng ciia xuc tac phuc [Co(Acac)]'' oxi phan tu dugc boat hoa theo phuang trinh sau:
[Co(Acac)]"' + O2 > [Co(Acac)02]*
[Co(Acac)02]* • [Co(Acac)]^* + 2 0 *
Theo [I, 3, 6, 7] dudi tac dyng ciia xuc tac phdc [Co(Acac)]* thi O2 phan td sau khi dugc hoat hoa thanh oxi nguyen tu O* dugc gin vao nguyen tu cacbon co noi doi t^o thanh peroxit.
HOOC - (CH2)7 - CH = CH - CH2 - CH - (CH2)5 - CH3 + 2 0 *
1 Xiic tac
OH '•
HOOC - (CHj), - CH - CH - CH, - CH - (CH,), - CHj 0 — 0 OH
> Giai doan tiip theo di hydroperoxit, ddng thai tao ra cdc gdc ttr do cho qud trinh tning hop. day dit^c cot la glai doan khoi mao cho qud trinh trung hap.
HOOC - (CH2), - CH = CH - CH - CH, - CH - (CHi), - CH3 2S^1% RO* + OH"
HOO OH
Cac ^oc tir do RO* tra thanh cac trung tam phan ung, tijp t(ic tin cong vao cac phan til dau d6 tao thanh cac goc tu do moi, qua trinh cu thS diln ra rat nhanh va lien tuc, tao ra mang hop chat cao phan til lam nhanh kho be m^t mang m\rc In.
> Giai doan trung hpp theo ca chi mach gdc.
- C H , - C H = C H - + 2 0 * ,. - C H 2 - C H - C H - t. - C H = C H - C H -
I I I
0 — 0 OOH - C H 2 - C H = CH - C H z -
: H 2 - C H 2 - C H -
1
0 0 CH = C H - C H -
1
-CH^ = C H -
- C H 2 - C H 2 - C H 0 0
1
- C H - C H - C H
1 1
0 — 0
TCHH, T. 52(1), 2014
Cd the hinh dung mang myc in sau khi khd ta cac mach polyme mach thing, hoac co the cd cau tao mang ludi khdng gian. Ve nguyen tac pha dau chi la nhihig chat mang de bao ve chat mau cd djnh tren be mSt giay sau khi in, khdng bj biin d^ng khi chju tae d^ng va biin ddi mau sic tren san phim in. Sau khi dugc hoat hoa cac nguyen td oxi tham nhap vao cac noi doi ciia cac phan tu axit hiiu ca khong no thuc hi?n phan ung triing hgp, lam khd bS mat mang myc phii tten be mat vat lieu in gan nhu ngay lap tuc.
2.3. Khao sat thdi gian kho cua mang mure Mang myc in nhii tuang nudc ttong dau, dugc in tten be mat giay Couche lang bdng co djnh lugng 250 g/m^ tten he thing Id gdm 3 true Id: 16 cap, 16 cha va 16 ep in, de tao ra ldp mang myc co dp day dong deu nhu nhau d cimg dieu kien nhiet dp 25 °C va dg im 75 %. Thdi gian khd eua mang myc in dugc xac dinh bang phuang phap xoay ngdn tay cai [7]. Dling ngon tay cai ty len be mat mau kiem tta, xoay manh, be mat mang myc kh6ng hi lam ban, kh6ng CO dau ty vet thi chirng td mang myc da kho.
Le Vdn Huynh Cac mau dugc kiem tra djnh ky, ddi vdi miu khdng su dung xiic tac phuc [Co(Acac)]' thi sau khoang 30s mgt lan, cdn ddi vdi mau cd su dung xuc tac phuc [Co(Acac)]* thi sau khoang 1 Os mgt lan. Rieng 30s cuoi d ca 2 mau thii la sau khoang 5s mgt lin thu. Viec xay dyng cac budc kiem tta dya tten co sd cac tai Heu tham khao va ket qua khao sat so bg trudc do.
3. KET QUA VA T H A O LUAN
Moi thi nghiem dugc lap di lap lai 3 lin dl liy ket qua trung binh. Ket qua nghien cuu dugc the hien tten bang 1 cho thay, khi mye in nhu tuang nudc trong dau chua dung chat xuc tac, thdi gian khd ciia mang myc in la khoang 223 s. Trong khi do khi dung them chat xuc tac phdc [Co(Acac)]* thi thdi gian kh6 eua mang myc in la 65 s. Dieu do cho thay anh hudng ciia xuc tac phuc [Co(Acac)]* den toe do lam khd ciia mang myc in tten giay la rat ldn, giam gan bon lan, do dd toe do ciia may m cai thien dang kl dl tang san lugng, xong chat lugng van dugc dam bao.
Bdng 1: Thdi gian khd hoan toan cua mang myc in nhii tuang nudc trong diu Mau
TN 1 2 3 4 5 6 7 8 9 TB
Muc nhu tucmg khong c6 xuc tac phuc Thai gian kho (s)
221 220 224 224 225 222 223 224 224 223
Toe do may in Toe dp may in toi da 1800 ta/h hay khoang 2s/l to
bao khong bi nhoe mat sau ta in khac
Muc nhu tucmg co xiic tac phuc [Co(Acac)]*
Thai gian kho (s) 64 66 65 66 65 65 66 64 64 65
Toe dp may in T6c do may in toi da 7200 ta/h hay khoang 2 ta/s
ChSt \\xqr\% ta in van dam bao khong bi nhoe mat sau to in khae
San lugng eua may in ttong qua trinh in, phu thupc rat ldn vao thdi gian kho be mat ciia mang myc in tren be mat giay, ma san pham in van dam bio chit lugng, dieu do phu thugc vao tie do trimg hgp ming myc in dudi tac dung ciia xuc tac phiic [Co(Acac)]* dong vai trd quan ttgng, coi nhu la phan litig khai mao cho cac phan ting trirng hgp tiep theo dien ra vdi toe dg rit Idn hinh 1, din din toe &^ may in tang len hinh 2. Nhu v^y, dudi tac dyng ciia xiic tic phdc [Co(Acac)]* d3 cai thien dang ke qua ttinh lim kh6 mang myc in nhu tuang nudc ttong dau, ket
qua nghien cihi la ca sd khoa hgc cho viec img dgng xuc tac phue vao qua trinh san xuit mye in diing cho may inky thuat so.
Danh gia chat lugng myc in nhu tuong khi diing chat lam kho la xiic tac phirc [Co(Acac)]*:
Dp nhdt: Myc nhii tuang nudc trong dau co dg nhdt khoang 3400-3900 Poise dugc do bing miy do dg nhdt Brookfield t^i Trung tam Polyme, Trudng Dai hgc Bach khoa Ha Ngi.
Kilm tra dg dinh: Khi ngdn tay dugc nhac len khdi be m$t giiy, ddng myc bj dirt ngay l|p tire vi
TCHH, T. 52(1), 2014
khdng gay cam giac ngdn tay bj giu lai tren giay, dilu nay chirng to la myc cd do dinh dam bao, kh6ng gay hien tugng lam tic ludi ho|c khdng truyin dugc myc trong qua trinh in.
1
200 -
50
t(s) (a)
itei/5::^-
mm
(b)
1 2
Hmh I: Thdi gian khd hoan toan cua mang myc in nhu tuong nudc ttong dau
(a) Khdng cd chat xuc tac phue (b) Cd chit xuc tac phuc
eooo 7000 6000 5000 4000 300 Q 2000 OOO 0
td in/gid
^ 2td/s
2s/td (c)
(d)
I-:
1
Hinh 2: Toe do may khi in myc nhii tuang nudc ttong dau
(c) Khdng cd chat xiie tae phdc (d) Cd chit xiie tae phdc Kiem tra dg dai ngan cua mye: Bang each cho myc dinh vao gida 2 dau ngdn tay rdi budng dan ra de Idem tra kha nang keo dai cua myc. Kit qua cho thay hai loai myc cd dg ngin la tuang duong nhau.
Kiem tta dp tach nudc: Sau khi chl tao myc dugc luu tt& d nhiet dp trung binh 25 °C ttong thdi gian khoang 90 ngay tiieo ddi, khdng thiy co hien tugng tach nudc, hinh dang myc van giu nhu ban dau khong thay doi, khong bi khd ldp myc.
Kiem tra dg tie ludi in: Qua trinh su dung myc in nhu tugng nudc trong dSu nhan thay rang: khi in mye xuing diu khdng gay tic ludi, khdng bj chay, cd dp khd nhanh tten m^t giiy, cd the giii myc dn
Nghien ciru qud trinh ldm nhanh kho...
dinh lau dai tt-ong frong in ma khdng sg myc lau ngay bi kho gay tic ludi inox, khi in khdng co hien tugng iam md ban in, chdng td myc ra deu, dong chiy myc t i t khi ep in, myc khdng lam nhoe phan tii in.
Kilm tta do phan giai: Kilm tra vdi cac gia ttj tang thd tir 5 %, 10 %, 15 %, 25 %, 40 %, 50 %, 60 %, 70 Vo, 80 %, 100 % va mdt sd cac vdng tton, cac dudng net manh cd do day net thay ddi tu 0,05 din 1,25 pt cho kit qua cd do phan giai tdt.
Kilm tra do phu ciia mang myc in: Myc in cd do thim hiit tdt tren giiy sau khi in, khong bi nhoe myc, bao phu tdt cac phin tu in, hien ro tang thu, cac diim T.ram cung nhu do day mang myc dong deu, dg xuyen thim tit. Cd dg thim hut tdt tren,giay sau khi in, khdng bj nhoe myc, bao phii tdt eac phin tu- in, hifn ro ting thu, cac diim T.ram cung nhu dg day mang mye ddng deu, dg xuyen thim tot.
Tom Iai: Myc nhii tuang sd dung chit lam nhanh kho la xuc tac phdc [Co(Acac)]'^, cd dp dinh, dp oin, do bdng, do thim hut, cudng do mau, do phan giai, tinh nang in tdt dap dng dugc yeu cau cua may in ky thuat sd hien dai.
4. KET LUAN
Sd dung chat lam nhanh kho mang myc in nhu tucmg nudc trong dau bing xiie tac phdc tao bdi Co^^ va Axetylaxeton (Acac) da mang lai hieu qua dang kha quan, da nit ngin dugc thdi gian nhanh kh6 cua mang myc in td 223s xudng cdn 65s, do d6 cd the tang san lugng in len gip 4 lln, tang eong suat ciia he thdng in ky thuat sd hien dai.
Sy cd mat cua xuc tac phdc [Co(Acac)]* khong anh hudng tdi cac tinh chit luu biin va xuc tien ciia myc nhii tuang, do do khong anh hudng tdi tinh nang in cua myc, ddng thdi giup cho mang muc kho nhanh, chat lugng san pham ben dep dap ung dugc nhu cau eua xa hpi do tang tie do in len nhieu lan.
Kit qua nghien cdu cd y nghTa ung dyng thyc tien, md ra ttien vgng cho viec dng xiic dyng xiic tac phuc dong the oxi hoa khd vao ttong cae qua trinh cong nghe san xuat mang lai hieu qua kinh t l cao.
TAI LIEU THAM KHAO
1. Henman, Klaus Taubald, Dietrich Kuhn.
Naturwissenschaftliche Grundlagen fur die Polygrafische Industrie, VEB Fachbuchverlag Leipzig, Bimdesrepublik Deutschland (2004).
2 E. Hermanies. Polygrafische Technik, VEB Fachbuchverlag Leipzig, Bundesrepublik Deutschland (2008).
3. Mio Katsumi (JP). Drier for Offset Printing, European Paten, EP0412628, 02/1991.
TCHH, T. 52(1), 2014
t. Nelson R. Eldred. Chemistry for the Gre^^hic Art- GATF Press (2001).
5. Nelson R. Eldred. What the Printer Should Know about Ink - GATF Press (2001).
Le Van Hiiynh Adams, J. Christopher. Emulsion Inks, US Patent 7300507 (2007).
R. H. Leuach, R. J. Piece. The printing manual, Kluwer Academic PubUshers (2004).
Lien he: Le Vao Huynh
Trudng Dai hgc Kinh te - Ky thuat Cdng nghiep 353 Trin Hung Dao, Thanh p h i Nam Djnh va 456 Minh Khai, quan Hai Ba Trung Ha Npi Email: [email protected] Di?n thoai 0912 208 709.
