GB2172305A - Process for the chemical coloration of veneers - Google Patents
Process for the chemical coloration of veneers Download PDFInfo
- Publication number
- GB2172305A GB2172305A GB08605700A GB8605700A GB2172305A GB 2172305 A GB2172305 A GB 2172305A GB 08605700 A GB08605700 A GB 08605700A GB 8605700 A GB8605700 A GB 8605700A GB 2172305 A GB2172305 A GB 2172305A
- Authority
- GB
- United Kingdom
- Prior art keywords
- veneers
- veneer
- wood
- coloured
- tanning substance
- 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.)
- Granted
Links
- 239000000126 substance Substances 0.000 title claims abstract description 36
- 238000000034 method Methods 0.000 title claims abstract description 22
- 239000002023 wood Substances 0.000 claims abstract description 19
- 238000010186 staining Methods 0.000 claims abstract description 10
- 238000011282 treatment Methods 0.000 claims abstract description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 6
- 235000010099 Fagus sylvatica Nutrition 0.000 claims abstract description 6
- 229910052802 copper Inorganic materials 0.000 claims abstract description 6
- 239000010949 copper Substances 0.000 claims abstract description 6
- 240000006909 Tilia x europaea Species 0.000 claims abstract description 5
- 235000018185 Betula X alpestris Nutrition 0.000 claims abstract description 4
- 235000018212 Betula X uliginosa Nutrition 0.000 claims abstract description 4
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical class [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims abstract description 4
- 240000000731 Fagus sylvatica Species 0.000 claims abstract 2
- 235000003891 ferrous sulphate Nutrition 0.000 claims description 3
- 239000011790 ferrous sulphate Substances 0.000 claims description 3
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 2
- 239000007864 aqueous solution Substances 0.000 claims 1
- 230000035515 penetration Effects 0.000 abstract description 8
- 241000219000 Populus Species 0.000 abstract description 5
- 235000019646 color tone Nutrition 0.000 abstract description 5
- 238000010521 absorption reaction Methods 0.000 abstract 1
- 241001070947 Fagus Species 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 238000003780 insertion Methods 0.000 description 3
- 230000037431 insertion Effects 0.000 description 3
- 235000011149 sulphuric acid Nutrition 0.000 description 3
- 239000001117 sulphuric acid Substances 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- QIGBRXMKCJKVMJ-UHFFFAOYSA-N Hydroquinone Chemical compound OC1=CC=C(O)C=C1 QIGBRXMKCJKVMJ-UHFFFAOYSA-N 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- YCIMNLLNPGFGHC-UHFFFAOYSA-N catechol Chemical compound OC1=CC=CC=C1O YCIMNLLNPGFGHC-UHFFFAOYSA-N 0.000 description 2
- 238000004040 coloring Methods 0.000 description 2
- 238000012137 double-staining Methods 0.000 description 2
- 239000000975 dye Substances 0.000 description 2
- IMBKASBLAKCLEM-UHFFFAOYSA-L ferrous ammonium sulfate (anhydrous) Chemical compound [NH4+].[NH4+].[Fe+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O IMBKASBLAKCLEM-UHFFFAOYSA-L 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- WQGWDDDVZFFDIG-UHFFFAOYSA-N pyrogallol Chemical compound OC1=CC=CC(O)=C1O WQGWDDDVZFFDIG-UHFFFAOYSA-N 0.000 description 2
- 239000008234 soft water Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 241000218631 Coniferophyta Species 0.000 description 1
- 229920002522 Wood fibre Polymers 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005034 decoration Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- 159000000014 iron salts Chemical class 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 229940079877 pyrogallol Drugs 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- GHMLBKRAJCXXBS-UHFFFAOYSA-N resorcinol Chemical compound OC1=CC=CC(O)=C1 GHMLBKRAJCXXBS-UHFFFAOYSA-N 0.000 description 1
- 229960001755 resorcinol Drugs 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000011122 softwood Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 235000018553 tannin Nutrition 0.000 description 1
- 229920001864 tannin Polymers 0.000 description 1
- 239000001648 tannin Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
- B27K3/16—Inorganic impregnating agents
- B27K3/22—Compounds of zinc or copper
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
- B27K3/16—Inorganic impregnating agents
- B27K3/26—Compounds of iron, aluminium, or chromium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
- B27K5/02—Staining or dyeing wood; Bleaching wood
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Forests & Forestry (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Chemical And Physical Treatments For Wood And The Like (AREA)
Abstract
In a process for the chemical coloration of veneers, especially of deciduous timbers of low tanning substance content, the aim consists in achievement of a complete colour penetration of the veneer, retaining a positive stained image, under industrial conditions. For this purpose a tanning substance enrichment is achieved in deciduous timbers which guarantees a uniform absorption and distribution of active mordant substance in relatively short treatment times and a chemical colour tone development in the entire veneer cross-section. In accordance with the invention the veneers to be coloured are treated in an iron (II) salt staining bath in common with an auxiliary veneer with a mean tanning substance content of 2 to 7%. As auxiliary veneers there are considered those of the wood of the copper beech, the lime tree and/or the birch. The invention is applied in the improvement of veneers such as ash and poplar.
Description
SPECIFICATION
Process for the chemical coloration of veneers
The invention concerns a process for the improvement of home-grown veneers, especially from deciduous timbers of low tanning substance content, by uniform coloration throughout while maintaining the natural wood texture.
It is known to impart transparent colorations to veneer timbers. This is effected firstly by physical colour application by means of suitable dyestuff solutions, for which processes have also been developed which render possible the desired great depth of penetration of the dyestuff into the veneer. Apart from problems of colour uniformity, it becomes disturbingly noticeable above all here that, by reason of the greater absorptivity of the porous, naturally light, early wood parts, a negative image of the wood texture is obtained. The "artificial " impression caused by this circumstance even now sets close limits to the use of such coloured veneers for the design of furniture surfaces and internal decoration.
There is also the old craft of mordant treatment which consists in a colour tone development by chemical reaction of the active mordant substances pertaining to the timber predominantly with heavy metal salts. For timbers low in tanning substance there is used, in the form of what is called double staining, a twostage process in which the timber is pretreated with specific mprdant chemicals. For this purpose hydroquinone, pyrogallol, pyrocatechin, resorcin, gailic acid and tannin come under consideration. (For transference of the double-staining process on to the industrial scale mention would have to be made of the technological disadvantage that this, on account of the necessary intermediate water treatment, is a three-bath process. Intermediate drying is also sometimes carried out).
The advantage of mordant treatment is to be seen in that by reason of the higher tanning substance content in the denser parts of the wood (late wood and medullary rays) the image of the wood texture remains positive and even is intensified in desired manner.
However the main drawback consists in that the colour development takes place essentially on the surface of the timber. No adequate colour penetration occurs, so that if surface treatments (sanding) are necessary or even in the case of minor damage the unstained wood becomes visible. The deposit settling on the surface acts as covering colour which is superimposed upon and "blurs" the graining of the wood.
By reason of these disadvantages the mordant process is predominantly of interest for conifer timbers formed from thin walled wide cells, which therefore are better receptive to the chemicals.
In order to arrive at all at an acceptable colour penetration, long storage times of the impregnated wood are necessary. Thus in
USSR 390,948 it is proposed to store wood veneer impregnated with pyrocatechin and ferrous sulphate for at least 36 hours in a dense stack in order to obtain a veneer which is coloured throughout.
The aim of the invention consists in achieving a complete colour penetration of veneers in deciduous timbers of low tanning substance content, while retaining a positive stained image, according to the principle of chemical colour tone development in times acceptable for industrial coloration.
The invention is based upon the problem of providing conditions for a tanning substance enrichment in deciduous timbers which guarantees a uniform absortion and distribution of active mordant substance in relatively short treatment times and a chemical colour tone development in the entire veneer cross-section.
It has been found that veneers of timbers of low tanning substance content are completely coloured throughout in a single-bath process by means of iron (II) salt in a short time if, in common with the veneers to be coloured veneers of a timber type with a mean tanning substance content of 2 to 7% are additionally introduced into the stain bath. For this purpose there may be considered veneers of the wood of the copper beech, the birch and/or the lime tree. In this way even deciduous timbers of low tanning substance content which hitherto were not available to such coloration, as for example ash or poplar, are coloured.
As iron salts there come under consideration iron (II) sulphate and Mohr's salt (ammonium ferrous sulphate) which are dissolved in relatively low concentration in the staining bath. Concentrations of 0.5 - 5 g./l. are used. In order to avoid undesired precipitations in the staining bath, the water utilised should be as soft as possible, if necessary deionised water should be used. The pH value of the aqueous is adjusted to between 2.5 and 5 by means of acid, preferably sulphuric acid. Apart from the stabilisation of the bath, the addition of the acid also serves for the control of the desired colour depth. At the higher pH values the achieved coloration becomes stronger and covers any brown tones contained in the timber.
The veneers of the timber type to be treated are set or laid into the path in common with preferably copper beech, birch or lime veneers in a suitable holding device. This can be effected for example by alternate insertion. The mass ratio of the veneer to be treated in each case to the colouring aid veneer here amounts to 1 : 2 to 4 : 1. The colouring is affected preferably in the heated bath at 30 to 80"C. and is terminated after about 2 hours with the complete colour penetration of the veneers. Just as colour depth is controllable by means of the adjustment of the pH valve, so it is also controllable by way of the bath temperature. It is here valid that, with constant pH value, darker colorations are achieved in the higher temperature range. As a result of the coloration, modern grey-brown to grey-green colour tones are obtained.No flakiness or cloudiness of the coloration occurs, the positive graining image (dark wood reflection, light soft wood) is retained.
Surprisingly it has been found that the active mordant contained substances of the wood diffuse in a short time out of the auxiliary veneer functioning as tannning substance dispenser very uniformly into the entire crosssection even of the dense deciduous timber veneers, are drawn onto the wood fibres and here, with the iron salt present from the outset in low concentration in the bath,result in a uniform colour penetration. One special advantage consists in that this action proceeds in the single-bath process, without further intermediate or after-treatments of the veneer being necessary. Obviously the wood content substances taken from the dispenser veneer are available in a form more favourable to utilisation than is the case in treatments with specific artificial chemical additives.
It is especially remarkable that the advantage achievable according to the invention again no longer occurs in the case of timbers very rich in tanning substance with tanning substance contents above 7% (for example oak veneer). In this case a superficial deposition of the formed iron-tanning substance complex occurs and the colour penetration of the veneer is disturbed. The utility of the method is therefore limited to the stated range of auxiliary veneers with tanning substance contents of 2 to 7%. The determination of the tanning substance content here takes place according to the known instruction of SANDERMANN: W. Sandermann, Fundamentals of the Chemistry and Chemical Technology of wood. Akademische Verlagsgesellschaft Geest & Portig KG, Leipzig 1956, pp.
421 - 423.
Example 1
For the coloration of ash veneers a staining bath of 1.5 g./1. FeSO4 in soft water is prepared. The pH value of the bath is adjusted to 4.5 by means of sulphuric acid. An ash veneer and a copper beech veneer (tanning substance content 3.1% determined according to
SANDERMANN) are laid in alternation into a veneer insertion device.
After the bath has been heated to 40"C. the veneers are lowered into the staining bath and left therein for 2 hours without circulation of the liquid. After this time the veneers are taken from the bath, aliowed to drip and dried in the drier. The ash veneer has assumed a grey-green colour, the brown core being largely covered. A lighter grey-green tone, retaining the brown core, is obtained under the same conditions if the pH value of the staining bath is adjusted to 3.0.
Example 2
For the coloration of poplar veneers a staining bath is prepared by dissolving 5 g./1.of
Mohr's salt in soft water. A pH value of 4.5 is adjusted by addition of sulphuric acid. In alternation a poplar veneer, a copper beech veneer and lime veneer are laid into a veneer insertion device. Further procedure is as in
Example 1, but the bath temperature is set to 45"C. and the liquid is pumped around during the two-hour coloration operation.
The coloration of the poplar veneer obtained is brownish-grey with growth-regulated partial blueish zones
Claims (7)
1. Process for the chemical coloration of veneers of deciduous timbers of low tanning substance content by treatment of the veneers in a staining bath consisting of an aqueous solution of an iron (II) salt, characterised in that, in common with the veneers to be coloured, in addition a veneer having a mean tanning substance content of 2 to 7%, determinedby SANDERMANN's method, is put into the staining bath.
2. Process according to Claim 1, characterised in that in common with the veneers to be coloured in addition a veneer of the wood of the copper beech is inserted.
3. Process according to Claim 1, characterised in that in common with the veneers to be coloured in addition a veneer of the wood of the lime tree is inserted.
4. Process according to Claim 1, characterised in that in common with the veneers to be coloured, in addition a veneer of the wood of the birch tree is inserted.
5. Process according to Claim 1, characterised in the mass ratioof the veneer to be coloured to the additionally utilized auxiliary veneer amounts to 1 : 2 to 4: 1.
6. Process according to Claim 1, characterised in that iron (II) sulphate or ammonium ferrous sulphate in a concentration of 0.5 to 5 g./1. is used as iron (II) salt.
7. Process according to Claim 1, characterised in that the staining bath is adjusted to a pH value of 2.5 to 5. Process as claimed in claim 1, substantially as hereinbefore described.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DD85274135A DD235433A1 (en) | 1985-03-15 | 1985-03-15 | METHOD FOR THE CHEMICAL FAIRING OF VENEERS |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8605700D0 GB8605700D0 (en) | 1986-04-16 |
| GB2172305A true GB2172305A (en) | 1986-09-17 |
| GB2172305B GB2172305B (en) | 1988-07-13 |
Family
ID=5566048
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08605700A Expired GB2172305B (en) | 1985-03-15 | 1986-03-07 | Process for the chemical coloration of veneers |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS61263701A (en) |
| DD (1) | DD235433A1 (en) |
| DE (1) | DE3603865A1 (en) |
| GB (1) | GB2172305B (en) |
| IT (1) | IT1191256B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4570717B2 (en) * | 1999-12-22 | 2010-10-27 | 中国塗料株式会社 | Aqueous stain composition and substrate coloring method using the composition |
| WO2004018184A1 (en) * | 2002-08-16 | 2004-03-04 | Nolte-Möbel Gmbh & Co.Kg | Throughput method for the mechanical covering of large, wide furniture components |
| DE102014100864A1 (en) * | 2014-01-27 | 2015-07-30 | Georg-August-Universität Göttingen Stiftung Öffentlichen Rechts | Coloring of wood and wood-based materials as well as corresponding wood and wood-based materials |
-
1985
- 1985-03-15 DD DD85274135A patent/DD235433A1/en not_active IP Right Cessation
-
1986
- 1986-02-07 DE DE19863603865 patent/DE3603865A1/en not_active Withdrawn
- 1986-03-07 IT IT47739/86A patent/IT1191256B/en active
- 1986-03-07 GB GB08605700A patent/GB2172305B/en not_active Expired
- 1986-03-15 JP JP61056114A patent/JPS61263701A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DD235433A1 (en) | 1986-05-07 |
| JPS61263701A (en) | 1986-11-21 |
| DE3603865A1 (en) | 1986-09-25 |
| GB8605700D0 (en) | 1986-04-16 |
| IT1191256B (en) | 1988-02-24 |
| IT8647739A0 (en) | 1986-03-07 |
| GB2172305B (en) | 1988-07-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |