AU650383B2 - Method for reducing viscosity of tannin extracted from pine bark - Google Patents
Method for reducing viscosity of tannin extracted from pine bark Download PDFInfo
- Publication number
- AU650383B2 AU650383B2 AU32140/93A AU3214093A AU650383B2 AU 650383 B2 AU650383 B2 AU 650383B2 AU 32140/93 A AU32140/93 A AU 32140/93A AU 3214093 A AU3214093 A AU 3214093A AU 650383 B2 AU650383 B2 AU 650383B2
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- AU
- Australia
- Prior art keywords
- tannin
- extract
- viscosity
- surfactant
- surfactants
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 229920001864 tannin Polymers 0.000 title claims description 46
- 239000001648 tannin Substances 0.000 title claims description 46
- 235000018553 tannin Nutrition 0.000 title claims description 46
- 238000000034 method Methods 0.000 title claims description 25
- 235000010204 pine bark Nutrition 0.000 title claims description 6
- 239000000284 extract Substances 0.000 claims description 29
- 239000004094 surface-active agent Substances 0.000 claims description 18
- 238000000605 extraction Methods 0.000 claims description 16
- 239000000203 mixture Substances 0.000 claims description 14
- 239000000853 adhesive Substances 0.000 claims description 11
- 230000001070 adhesive effect Effects 0.000 claims description 11
- 125000002091 cationic group Chemical group 0.000 claims description 10
- 239000002736 nonionic surfactant Substances 0.000 claims description 9
- 235000008331 Pinus X rigitaeda Nutrition 0.000 claims description 7
- 235000011613 Pinus brutia Nutrition 0.000 claims description 7
- 241000018646 Pinus brutia Species 0.000 claims description 7
- 239000003093 cationic surfactant Substances 0.000 claims description 7
- 241000894007 species Species 0.000 claims description 6
- 150000001412 amines Chemical class 0.000 claims description 5
- 230000009467 reduction Effects 0.000 claims description 3
- 244000068988 Glycine max Species 0.000 claims description 2
- 235000010469 Glycine max Nutrition 0.000 claims description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims 1
- 239000005977 Ethylene Substances 0.000 claims 1
- 239000007787 solid Substances 0.000 description 10
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 6
- 210000000051 wattle Anatomy 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 4
- 239000004202 carbamide Substances 0.000 description 4
- 239000002023 wood Substances 0.000 description 4
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 3
- 238000009472 formulation Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000011282 treatment Methods 0.000 description 3
- 235000008577 Pinus radiata Nutrition 0.000 description 2
- 241000218621 Pinus radiata Species 0.000 description 2
- 229920001807 Urea-formaldehyde Polymers 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 150000001447 alkali salts Chemical class 0.000 description 2
- 125000003118 aryl group Chemical group 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 229920001568 phenolic resin Polymers 0.000 description 2
- ODGAOXROABLFNM-UHFFFAOYSA-N polynoxylin Chemical compound O=C.NC(N)=O ODGAOXROABLFNM-UHFFFAOYSA-N 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 241000196324 Embryophyta Species 0.000 description 1
- IAYPIBMASNFSPL-UHFFFAOYSA-N Ethylene oxide Chemical compound C1CO1 IAYPIBMASNFSPL-UHFFFAOYSA-N 0.000 description 1
- 229930040373 Paraformaldehyde Natural products 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 238000007385 chemical modification Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- SLGWESQGEUXWJQ-UHFFFAOYSA-N formaldehyde;phenol Chemical compound O=C.OC1=CC=CC=C1 SLGWESQGEUXWJQ-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000002715 modification method Methods 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 229920002866 paraformaldehyde Polymers 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- 150000008442 polyphenolic compounds Chemical class 0.000 description 1
- 235000013824 polyphenols Nutrition 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 231100000916 relative toxicity Toxicity 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 230000000979 retarding effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 235000000346 sugar Nutrition 0.000 description 1
- 150000008163 sugars Chemical class 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 239000004634 thermosetting polymer Substances 0.000 description 1
Landscapes
- Adhesives Or Adhesive Processes (AREA)
Description
r SLI:i ~i f re
AUSTRALIA
"0383 Patents Act 1990 CSR LIMITED
ORIGINAL
COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Method for Reducing Viscosity of Tannin Extracted from Pine Bark The following statement is a full description of this invention including the best method of performing it known to us:- -2- METHOD FOR REDUCING VISCOSITY OF TANNIN EXTRACTED FROM PINE BARK Field of the Invention This invention relates to methods for reducing the viscosity of concentrated solutions of tannin extracted from the bark of Pinus radiata and similar tree species.
This invention also relates to compositions including such tannins which have reduced viscosity and to adhesive compositions based on these tannins.
Background to the Invention Wattle bark tannin extract has been used successfully for many years as the major component in thermosetting adhesive formulations for the manufacture of reconstituted wood products.
Various methods have been disclosed for the aqueous extraction and utilisation of pine bark tannin, but because of high reactivity and viscosity compared with wattle bark tannin, chemical modification during and/or after extraction has generally been employed. This has lessened the durability properties of the adhesive bonds obtained in reconstituted wood products.
In Australian patent application 61467/90, there is disclosed a method of tannin extraction without resort to chemicals. Good extraction efficiencies have been 25 obtained with this method but when the hot water extract 0 so is concentrated to a solids content required for adhesives, (eg 33-43% solids), the resultant high -viscosity does not allow it to be used in an untreated form.
It is suggested in that application, that phenol in a concentration of around 3 5% on tannin solids can be used to reduce viscosity. The phenol is said to be capable of retarding mold growth which might otherwise be encouraged by the presence of sugars and gums in the extract.
L- 3 The present inventors found, however, that not only does phenol present handling difficulties due to its relative toxicity but that it is far less effective in viscosity reduction than the method described in the present invention. Furthermore it was found that mold growth could be easily prevented by storing tannin extract in airtight, sealed containers.
It is also known to use ethanol to reduce viscosity of aqueous tannin extract. Urea has also been suggested for the same purpose.
Description of the Invention This invention provides an alternative method of *reducing pine bark tannin viscosity, without prejudicing its potential adhesive applications.
A method is described for substantially reducing the viscosity of pine bark tannin extracts which is particularly useful where hot water is the only extractant. We have found that various surfactants of the cationic and especially non-ionic types are particularly effective for this purpose.
Accordingly in a first aspect, the present invention consists in a method for reducing the viscosity of tannin extracts derived from the bark of pine and related species comprising adding to or including in the extract one or more cationic and/or nonionic surfactants or mixtures thereof in an amount sufficient to reduce the viscosity.
In a second aspect, the present invention further consists in a tannin based composition of reduced viscosity comprising a tannin extract derived from the bark of pine and related species and one or more cationic and/or nonionic surfactants or mixtures thereof.
In a third aspect, the present invention still further consists in an adhesive composition comprising a tannin extract derived from the bark of pine and related species and one or more cationic and/or nonionic 141 4 surfactants or mixtures thereof.
An example of this invention is the mixing of 0.5-2.0% Teric 16M15, a non-ionic surfactant manufactured by ICI Operations Pty Ltd, into a 35% solids content tannin extract solution. Teric 16M15 is a soya fatty amine plus 15 moles of ethylene oxide. A suitable addition is illustrated in Table 1 and related to tannin extract solids.
Table 1 o o ooo r~ono -oi o en ~ro
D
o~ o o ac o~i eo
I
i j
I
i ra -i ii__ 15 Component Mass in Grams Pine tannin extract Cationic/non-ionic surfactant 0.18-0.72 Water This particular surfactant in fact behaves as a cation in low pH solution. Radiata pine bark tannin extract solutions have a natural pH ranging from 3.5 to The resultant formulation undergoes a significant drop in viscosity of up to 3 to 5-fold, making it suitable for use in "boilproof" adhesive formulations with formaldehyde donor chemicals, such as para.ormaldehyde, in the manufacture of particleboard and other reconstituted wood products.
The present inventors believe this phenomenon is due to hydrogen bond breaking and dispersion that results from the cationic nature of the surfactant. Tannins are naturally occurring polyphenols that range in molecular weight from less than 1000 to more than 1 million. Strong internal hydrogen bonds occur between hydroxyl groups on the aromatic rings via the water molecules to form association complexes or colloidal agglomerates with limited solubility. The polymeric nature of the complex i i- I~l~b~ i i_ 5 causes the high viscosity. Cationic surfactants can act as dispersants due to electrostatic repulsion between themselves and the positively charged agglomerates. These surfactants also allow an alternative to the internal hydrogen bonding that exists between the tannin molecules. This is provided by the oxygen atoms in the ethoxylate chain of the surfactant, which compete with the hydroxyl groups on the aromatic rings.
This treatment may be applied, for further benefit, to the dilute extract prior to concentration, thus making operation of evaporators used to increase the concentration less difficult, and also increasing their ~efficiency. Indeed surfactants may be added during the bark extraction process to improve slurry mobility to 0 E 15 overcome difficulties that may occur in equipment 0 0 operation. The lowered viscosity is also particularly beneficial when low overall water/bark ratios are used to increase concentration of the extract obtained from the 0 extraction plant proper.
S 20 Accordingly in a further aspect, the present invention still further consists in an improvement to a 0 method for the aqueous extraction of tannin from the bark of pine and related species, the improvement comprising 2 including in an extraction solution one or more cationic 0 25 and/or nonionic surfactants or mixtures thereof.
0.
The advantages of this invention over previously disclosed methods are as follows: compared with the alkali/alkali salts modification method, there is no degradation of adhesive bond durability or need for other post-treatments such as pH adjustment and heating to improve extract performance.
compared with other hydrogen bond breakers, specifically ethanol, the lower loadings needed provide greater economy of use. Surfactants are I a i6 simpler and safer to store and use than ethanol; the extract is less prone to phase separation if it is treated and stored without stirring.
compared with urea, surfactants such as 16M15 are considerably more cost effective in reducing viscosity and do not degrade the durability of adhesive bonds that occurs when urea loadings are sufficient to cause a significant viscosity reduction.
compared to highly volatile hydrogen bond breakers such as ethanol, surfactants may also be used to treat the dilute tannin extract before evaporation to solids contents required for adhesive use, improve the fluidity and hence handling characteristics of bark slurry, maintain "solubilisation" of tannin during extraction from bark and facilitate evapoxator operation.
Use of appropriate surfactants assists in obtaining high extraction efficiency and, by enabling extraction to be conducted at lower overall water/bark ratios, allows increased extract concentration to be achieved.
This invention provides for the manufacture of reconstituted timber products without suffering the loss of durability properties experienced with alkali/alkali salt treatments of tannin extracts.
Table 2 shows that thickness swell in boiling water tests are comparable with or better than results for boards made with wattle tannin and phenolformaldehyde resins.
L.,~Ri~S-~C1C-r~a~ C-P~
B
~irmasras~,~; i
L
-7 Table 2 0r10 00cr 0 o a o os o aa c It a
B
THERMOSET RESIN SYSTEM RESIN LOADINGS ON THICKNESS DRY WOOD FURNISH SWELL WEIGHT IN 3 LAYER AFTER 1 HR PARTICLEBOARD* BOIL
(SURFACE/CORE)
SURFACTANT TREATED PINE 12.3% 10% 17% TANNIN 8% PARAFORMALDEHYDE (based on tannin solids) WATTLE TANNIN 17% 12.3% 10.5% 22% 15 UREA-FORMALDEHYDE CONCENTRATE (based on tannin solids) (surface)/MELAMINE-
UREA-FORMALDEHYDE
(core) PHENOL-FORMALDEHYDE 11% 8% 26% (surface)/WATTLE TANNIN 17% UREA 25 FORMALDEHYDE CONCENTRATE (based on tannin solids) (core) expressed as tannin solids for pine and wattle tannin examples.
i «o 0 0 1 CS 60 8 It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.
c; ocra a oe a
I
i~_
Claims (7)
- 2. A method as in claim 1 wherein surfactant is added to the extraction solution following extraction of the tannin into the solution.
- 3. A method as in claim 1 wherein surfactant is included in the aqueous extraction solution prior to or during extraction of the tannin into the solution.
- 4. A method for reducing the viscosity of an aqueous tannin extract derived from the bark of pine and related 0 species comprising adding to or including in the extract 0 0 15 one or more cationic and/or nonionic surfactants or mixtures thereof in an amount sufficient to reduce the viscosity of the extract. A method as in any one of the preceding claims wherein the surfactants are one or more nonionic S 20 surfactants.
- 6. A method as in claim 5 wherein the surfactant is a 0 0fatty amine ethoxylate.
- 7. A method as in claim 6 wherein the fatty amine ethoxylate is a soya fatty amine with 15 moles of ethylene S 25 oxide.
- 8. A method as in any one of the preceding claims wherein the cationic and/or nonionic surfactant is included in the extract or the extraction solution in a 7.A surfactant:tannin ratio of from 18-72:3500 on a weight basis.
- 9. A tannin based composition comprising a tannin extract obtained from a method as claimed in any one of claims 1 to 3 or 5 to 8. 0 i L i L IL---LII~-~IIIII 10 An adhesive composition comprising a tannin extract obtained from a method as claimed in any one of claims 1 to 3 or 5 to 8. DATED this 29 day of January 1993 CSR LIMITED Patent Attorneys for the Applicant: F.B. RICE CO. i F 11 ABSTRACT A method for the reduction of viscosity of aqueous tannin extracts of pine bark is disclosed. The method comprises the use of a cationic and/or nonionic surfactant in the extract in an amount effective to reduce the I °viscosity to a satisfactory level. Fatty amine ethoxylates are preferred nonionic surfactants. i e i i s a I 0 0
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU32140/93A AU650383B2 (en) | 1992-01-29 | 1993-01-29 | Method for reducing viscosity of tannin extracted from pine bark |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPL0604 | 1992-01-29 | ||
| AUPL060492 | 1992-01-29 | ||
| AU32140/93A AU650383B2 (en) | 1992-01-29 | 1993-01-29 | Method for reducing viscosity of tannin extracted from pine bark |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU3214093A AU3214093A (en) | 1993-08-05 |
| AU650383B2 true AU650383B2 (en) | 1994-06-16 |
Family
ID=25622022
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU32140/93A Ceased AU650383B2 (en) | 1992-01-29 | 1993-01-29 | Method for reducing viscosity of tannin extracted from pine bark |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU650383B2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU629029B2 (en) * | 1989-08-08 | 1992-09-24 | Chem Eng Contracts Pty Limited | Tannin extraction |
-
1993
- 1993-01-29 AU AU32140/93A patent/AU650383B2/en not_active Ceased
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU629029B2 (en) * | 1989-08-08 | 1992-09-24 | Chem Eng Contracts Pty Limited | Tannin extraction |
Also Published As
| Publication number | Publication date |
|---|---|
| AU3214093A (en) | 1993-08-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MK14 | Patent ceased section 143(a) (annual fees not paid) or expired |