KURARAY EXCEVAL TM. as dispersant for high water resistance polyvinyl acetate emulsion. Kuraray America Inc. PVOH / PVB Division

Transcription

1 KURARAY EXCEVAL TM as dispersant for high water resistance polyvinyl acetate emulsion

2 What s EXCEVAL TM? Water soluble ethylene vinyl alcohol vinyl acetate co-polymer CH 2 CH OH l CH 2 CH O C O CH 3 m CH 2 CH 2 n Special features using EXCEVAL TM as a dispersant are 1-component D3 level water resistance Better storage stability at low temperature Excellent long term viscosity stability No generation of formaldehyde eco-friendly!! Existent cross-linking system can be applied

3 Contents 1. Overview for high water resistance PVAc adehesive 2. General properties of EXCEVAL TM 3. Dispersant for emulsion polymerization 3-1. Polymerization method 3-2. For D3-adhesive - without cross-linking system Adhesive with cross-linking system 4. Summary

4 PVOH as a protective colloid PVAc P(Et-VAc) PVOH protective colloid layer <PVOH> Degree of polymerization Degree of hydrolysis Em Viscosity Rheology PVOH protective colloid Em model Stability

5 PVOH as a protective colloid PVOH protective colloid layer PVAc P(Et-VAc) drying PVAc PVA PVOH protective colloid Em model PVOH generate continuous layer in the film PVOH protective colloid Em model

6 PVOH as a protective colloid <PVOH> Degree of polymerization Degree of hydrolysis Modification PVOH property strongly affect not only emulsion property but also obtained film property o C, 65%RH Em Viscosity Rheology Film Mechanical Property Stress(kg/cm 2 ) PVOH system Emulsifier system Stability Strain(%)

7 High water resistance poly vinyl acetate adhesive Water resistance; It is difficult to get high water resistance without crosslinking because PVOH itself is water soluble. Water resistance category for wood adhesive (European standard) D1 D2 D3 D4 Usual PVAc Em PVAc Em with cross-linking Target of using EXCEVAL TM Poly condensation type adhesive melamine-urea resin Phenol-formaldehyde resin household furniture wooden floor etc Bonded wood which need higher water resistance

8 High water resistance poly vinyl acetate adhesive <Problems of current PVAc-Em D3 adhesive> Major technical trend; Vinyl acetate with NMA (N-Methylol Acrylamide) system - reaction of methylol group and hydroxy group in PVOH - 1. Long term storage stability is too bad Methylol group react with hydroxy group even at room temperature and viscosity of the product is gradually increased 2. Generation of formaldehyde Methylol group reaction generates formaldehyde and formaldehyde is bad for human health. ( Formaldehyde is restricted in some Asian countries. )

9 What s EXCEVAL TM? For high water resistance what Kuraray thought about was Raise the water resistance of PVOH itself Water soluble ethylene vinyl alcohol vinyl acetate co-polymer CH 2 CH OH l CH 2 CH O C O CH 3 m CH 2 CH 2 n EXCEVAL TM

10 Contents 1. Overview for high water resistance PVAc adehesive 2. General properties of EXCEVAL TM 3. Dispersant for emulsion polymerization 3-1. Polymerization method 3-2. For D3-adhesive - without cross-linking system Adhesive with cross-linking system 4. Summary

11 Grade name of EXCEVAL TM RS Indicate the degree of modification low 1-4 high DP x 100; Degree of polymerization 17 x 100; 1700 DH 1 Fully hydrolyzed ; 98 mol% 7 Medium hydrolyzed ; 93 mol% 0 Super hydrolyzed ; >99 mol%

12 Grade of EXCEVAL TM Super hydrolyzed Fully hydrolyzed Medium hydrolyzed 1) of a 4 % aqueous solution at 20 C determined by Brookfield synchronised rotary-type viscometer. 2) calculated as Na2O Grade HR-3010 RS-2117 AQ-4104 RS ) after 3 hours drying at 105 C. Methanol content: less than 3 %. Viscosity 1) JIS K6726 [mpa s] Degree of hydrolysis (saponification) [mol.-%] Max Ash content 2) [%] Max Volitile content 3) [%]

13 Water resistance of EXCEVAL TM <Method> Dipping the film to water Temp: 20 degc Time: 1 hour Standard PVOH EXCEVAL TM Standard PVOH EXCEVAL TM

14 Water resistance of EXCEVAL TM swelling solubility (times) (% ) RS PVA-117 >30 >70 dipped for 24h r s at 20 o C water swe llin g:b/a solu bility:(1-c/a)x100 Weight a b c PVOH film Dipped into water dried Pull out from water (Swelled)

15 Viscosity stability at low temperature Fully hydrolyzed EXCEVAL TM

16 Surface activity of EXCEVAL TM Low Surface activity Surface tension (mn/m) Fully hydrolyzed EXCEVAL TM 20 o C Conventional PVA (PVA-117) RS-2117 High Concentration (%)

17 Contents 1. Overview for high water resistance PVAc adehesive 2. General properties of EXCEVAL TM 3. Dispersant for emulsion polymerization 3-1. Polymerization method 3-2. For D3-adhesive - without cross-linking system Adhesive with cross-linking system 4. Summary

18 Polymerization Procedure Dissolve EXCEVAL TM Temp : 60 o C VAM (5-10%) TA Initial polymerization EXCEVAL TM : min 5-10 parts / VAM NaOAc: parts / PVOH Add HPO 30-60min Temp: o C Adjust ph Filtration End of VAM addition & Maturation VAM constantly 2-6 hrs initiator; H 2 O 2 /tartaric acid system (2/1, mol/mol) Add HPO (constantly)

19 Results of polymerization Condition Em property Stabilizer Initiator TSC Viscosity 20rpm Storage stability (phm) (%) (mpa s) 0 o C 40 o C 1 RS HPO HR HPO PVA HPO gellation PVA HPO RS KPS polymerization w asn't stable 6 D3-Em HPO: H 2 O 2 /Tartaric acid KPS: KPS/NaHSO 4 Stor age s tability:put the Em at 0 o C and 40 o C, s tability = η(after 7 days )/η(after 0 days ) D3-Em:commercially avairable D3 product

20 Adhesive strength of wood Adhesive Strength kg/cm Based on J.I.S. Dipped in 60 o C water for 3hrs Wood : Birch RS-2117 HR-3010 PVA-117 PVA-217 Existing D3-Em JIS; Japanese Industrial Standard PVA-117; Conventional fully hydrolyzed PVOH PVA-217; Conventional partially hydrolyzed PVOH

21 Adhesive strength of wood Protective Crosslink er A dhesive Property colloid D2 D3 Sequence 2 Sequence 3 Sequence 4 > 8N/mm 2 > 2N/mm 2 > 8N/mm 2 1 HR-3010 none (10phm) 2 RS-2117 none (7.5phm) ref. D3-Em A dhesive property;m easured based on BS EN204. sequence2; 3 hours in cold water,7days at 65%RH, 20 o C sequence3; 4 days in cold water, samples tested wet at 20 o C sequence4; 4 days in cold water,7days at 65%RH, 20 o C D3-Em; commercially available D3-Em Measured by FIRA International Ltd (Official organization) Maxwell Road, Stevenage, Hertfordshire SGI 2EW, England Telephone +44(0) Facsimile +44(0) info@fira.co.uk website:

22 Adhesive strength with cross-linking EXCEVAL TM is used same as conventional PVOH and existing cross-linking system can be applied for further water resistance. 1. NMA type cross-linker 2. Acrylic acid + Al compound 3. Other post added cross-linker

23 Results of polymerization Polymerization with cross-linking system ( VAM-AA co-polymn.+al(no 3 ) 3 ) Stabilizer TSC Viscosity 20rpm Storage stability 1) (phm) (%) (mpa s) 0 o C 40 o C (times) (times) 1 HR RS RS PVA ref. D3-Em 2) )Storage stability : put th e Em at 0 o C and 40 o C, stability =η(after 7 days) /η(after 0 days) 2)Commercially available D3-Em(Stand ard Em in Europe) Acrylic acid : 1wt%/VAM, Al(NO 3 ) 3 9H 2 O: half molar to AA

24 Adhesive strength of wood Polymerization with cross-linking system ( VAM-AA co-polymn.+al(no 3 ) 3 ) 60oCwater Boiling Adhesive Strength kg/cm Based on J.I.S. Dipped in 60 o C or boiling water for 3hrs Wood : Western hemlock RS-2117 HR-3010 RS-1717 PVA-617 Existing D3-Em AA; Acrylic acid JIS; Japanese Industrial Standard PVA-617; Conventional intermediately hydrolyzed PVOH

25 Adhesive strength of wood Polymerization with cross-linking system ( VAM-AA co-polymn.+al(no 3 ) 3 ) Protective A dhesive Property colloid D3 D > 2N/mm 2 > 8N/mm 2 > 4N/mm 2 > 8N/mm 2 1 RS (7.5phm) ref. D3-Em A dhesive property;measured based on BS EN204. sequence3; 4 days in cold water at 20 o C samples tested wet sequence4; 4 days in cold water,7days at 65%RH and 20 o C sequence5; 6 hours in boiling water at 20 o C samples tested wet sequence6; 6 hours in boiling water,7days at 65%RH and 20 o C D3-Em;comm ercially available D3-Em

26 Contents 1. Overview for high water resistance PVAc adehesive 2. General properties of EXCEVAL TM 3. Dispersant for emulsion polymerization 3-1. Polymerization method 3-2. For D3-adhesive - without cross-linking system Adhesive with cross-linking system 4. Summary

27 Summary of EXCEVAL TM Water soluble ethylene vinyl alcohol vinyl acetate co-polymer, specially designed as a dispersant for emulsion polymerization. 1-component D3 level water resistance Better storage stability at low temperature Excellent long term viscosity stability No generation of formaldehyde - eco-friendly!! - Existent cross-linking system can be applied for further water resistance

28 Notices for using EXCEVAL TM Typical polymerization procedure should be used. 1. Initiator of polymerization should be hydrogen peroxide / tartaric acid Persulfate system (KPS, APS) doesn t work in fully hydrolyzed EXCEVAL TM system. 2. Polymerization temperature should be above 80 deg C.