CA1170969A - Process for producing multilayer particleboard - Google Patents
Process for producing multilayer particleboardInfo
- Publication number
- CA1170969A CA1170969A CA000400715A CA400715A CA1170969A CA 1170969 A CA1170969 A CA 1170969A CA 000400715 A CA000400715 A CA 000400715A CA 400715 A CA400715 A CA 400715A CA 1170969 A CA1170969 A CA 1170969A
- Authority
- CA
- Canada
- Prior art keywords
- percent
- particle board
- resin
- layer
- resins
- 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.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/08—Moulding or pressing
- B27N3/10—Moulding of mats
- B27N3/14—Distributing or orienting the particles or fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/002—Manufacture of substantially flat articles, e.g. boards, from particles or fibres characterised by the type of binder
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L97/00—Compositions of lignin-containing materials
- C08L97/02—Lignocellulosic material, e.g. wood, straw or bagasse
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Forests & Forestry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Materials Engineering (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Laminated Bodies (AREA)
- Dry Formation Of Fiberboard And The Like (AREA)
- Adhesives Or Adhesive Processes (AREA)
- Phenolic Resins Or Amino Resins (AREA)
- Table Devices Or Equipment (AREA)
- Paper (AREA)
- Ceramic Capacitors (AREA)
Abstract
PROCESS FOR PRODUCING MULTI-LAYER PARTICLE BOARD
(D#71,200-DTA-160-F) ABSTRACT
A process for producing triple and multi layer particle board wherein phenol formaldehyde resins are used in gluing particles to form the outer-layers of a particle board. The phenol formaldehyde resins used have a processing viscosity of 3000 mPas maximum, a solids content of between 20 and 30 percent, and an alkali content below 8 percent.
- I -
(D#71,200-DTA-160-F) ABSTRACT
A process for producing triple and multi layer particle board wherein phenol formaldehyde resins are used in gluing particles to form the outer-layers of a particle board. The phenol formaldehyde resins used have a processing viscosity of 3000 mPas maximum, a solids content of between 20 and 30 percent, and an alkali content below 8 percent.
- I -
Description
-117~)969 PROCESS FOR PRODUCING MULTI-LAYER PARTICLE BOARD
(D~ 71,200-DTA-160-F) BACKGROUND OF THE INVENTION
Outer layers of triple and multi-layer particle board are normally prepared using the same phenolic resin glues as in the center layers. Whilst the high reactivity of such 45 - 48 percent aqueous resins is highly efficient in the center layers, it causes embrittlement of the surface in the outer layers. Moreover, owing to the high alkalinity of such previously used resins which is required for the rapid setting of the center-layer, alkali-rich dust is obtained when grinding such particle board. On incineration this dust destroys the furnaces.
In view of the abov~e mentioned difficulties, special phenolic resins for the outer layers of particle boards were developed several years ago, which do not show the described disadvantages. The disadvantages were removed by lowering the alkali content of the 45 - 48 percent aqueous resins from 9 percent and also lowering the formaldehyde content in order to reduce the reactivity and to secure sufficient storage stability.
The phenol content in the resins was thus raised by about 40 percent. Hence the price of the new outer-layer resins and consequently of the particle board prepared therefrom increased appreciably, because the amount of solid resin applied to the particles cannot be lowered, despite -- 1 -- ~
qP
117~969 the higher phenol content in the resin solutions, in order not to deteri-orate the particle board properties.
In Federal Republic of Germany Patent Application No.
P 29 44 178.9-43, now Patent No. 2,944,178 issued on November 26, 1981 by the same inventors as herein and assigned to the same assignee, a process for producing multi-layer particle board was disclosed, in which the outer-layer particles are glued with a phenol formaldehyde resin having with a viscosity of 30 to 90 seconds (4-mm DIN cup), a solids content of between 30 and 41 percent, and an alkali content of less than 8 percent.
DESCRIPTION OF THE INVENTION
U.S. 3,968,308 discloses a process for the manufacture of chip boards using condensation resins and binders and product.
SUMMARY OF THE INVENTION
As a further development of the process according to Federal Republic of Germany Patent No. 2,944,178, a process is now disclosed for the manufacture of triple and multi-layer particle board in which the outer-layer particles are glued with a phenolic resin which has a miximum viscos-ity of 3000 mPas, a solids content of between 20 and 30 percent, preferably between 25 and 30 percent, and an alkali content of below 8 percent, pre-ferably between 2 and 6 percent.
It has been found that by molecular enlargement of such resins, outer-layer phenolic resins are obtained which present the known advantages of alkali-poor resins and, furthermore, have a noticeably better quality so that the solids content relative to the particle can be lowered , 117(~969 by 30 percent and more. Hence the novel outer-layer resins for particle board are obtained by condensation in order to form very large molecules, the alkali contents and the viscosities of the resin solutions remain virtually un-changed, namely 20 - 100 seconds, particularly 30 - 90 seconds and preferably 30 - 70 seconds (4-mm DIN cup).
These resins contain only 30 - 41 percent solids according to Federal Republic of Germany Patent No. 2,944,178 and now it has been found that they can contain as few as 20 - 30 percent solids, preferably 25 - 30 percent, instead of 45 -48 percent which is still customary. The lower storage stability due to the noticeably larger molecular structure can be offset by lowering the formaldehyde content in the resins. The formaldehyde content is thus dependent on the desired storage stability.
The solids content in a resin is defined as the residue obtained after evaporation of water and possibly low-molecular compounds under specified conditions (1 gram, 120C, 2 hours). As a rule the solids content in particle board binders is by 5 to 7 percent lower than the theoreti-cal value. This is mainly due to release of reaction water.
The phenol formaldehyde resin may be replaced Dy phenolic resins prepared from formaldehyde or other lower aldehydes with 1 to 4 carbon atoms and alkyl derivatives of phenol with 1 to 9, preferably 1 to 4 carbon atoms in the alkyl group.
The high quality of the new outer-layer resins allows lowering of the gluing factor, i.e. the amount of 117~969 solid resin required per absolutely dry particle, from the 10 to 12 percent previously used to 6 to 8 percent, without impairing the quality. The water content in the particle mat may result in higher or lower moisture of the glued particles depending on the solids content in the resin solution and the gluing factor at a given particle moisture.
For instance, a 37 percent resin (glue application 8 percent, 13.6 kgs moisture per 100 kgs of absolutely dry particle) corresponds to a conventional 45 percent phenolic resin (glue application 11.2 percent), and a 29 percent resin (glue application 6 percent, 14.7 kgs moisture per 100 kgs of absolutely dry particle) corresponds to a conventional 45 percent phenolic resin (glue application 12 percent~, respectively.
Qualitative evaluation of the novel high-molecular phenolic resins for use in the outer layers of particle board in comparison with a conventional 45 percent outer-layer phenolic resin was carried out employing three-layer particle board specimens, the center-layer particles of which had been glued with a conventional, alkali-rich 45 percent aqueous phenolic resin.
The superior quality of the new phenolic resins in the outer layers of particle board is clearly demonstrated by the following examples:
il7(~969 EXAMPLES
TABLE I
Composition of the Resins (Parts by Weight) Resin A B C Standard Resin Phenol 234 218 174 284 Formalin (37~) 403 394 300 547 Sodium Hydroxide Solution (50%) 98 93 58 94 Water 265 295 468 75 Characteristics Solids, ~ 37 35 27 45 Viscosity, seconds 43 35 41 45 (4-mm DIN cup) Gel Time, min. 27 21 24 25 (at 100 C) These resins can be manufactured in accordance with the known conventional processes.
Preparation of Outer-Layer Resin A
Pour 234 parts of phenol and 403 parts of ormalin (37~) into a flask. Heat to 70C. Add 98 parts of sodium hydroxide solution (50%) within a period of 60 minutes.
Charge 265 parts of water and raise the temperature to 80C.
Cool the product when a viscosity of 35 seconds (4-mm DIN
cup) is attained.
The outer-layer resins B and C as well as the standard resin were prepared accordingly.
117(~969 Pre aration of the Center-LaYer Resin p Pour 203 parts by weight of phenol and 463 parts by weight of formalin (37~) into a flask. Heat to 80C.
Add 98 parts by weight of sodium hydroxide solution (50%) to the reaction mixture within a period of two hours. Cool the resin solution to 70C. When a viscosity of 50 seconds (8-mm DIN cup) is attained, dilute with 174 parts of sodium hydroxide solution (50%) and 62 parts of water. Cool the resin.
This 45 percent was employed as a center-layer binder in the experiments.
The resins were tested in 16-mm thick three-layer particle board. The outer layertcenter layer particle ratio in the test specimens was 35:65. The glue application to the particles which had been dried to lower the moisture to approximately 5 percent was 8 percent solids, relative to absolutely dry wood for the resins A and ~, 6 percent for resin C, and 11 percent for the standard resin~ In each of the cases the center-layer particles were glued with 8 percent solids of a conventional, alkali-rich phenolic resin. The moisture of the glued center-layer particles was 11.6 percent prior to pressing.
In each of the cases the particles were waterproofed with 1 percent paraffin relative to absolutely dry wood.
The particle mats were pressed for four minutes at 180C. The gross density- of the particle board thus prepared ranged between 680 and 690 kgs/m3.
1~7096'~}
TABLE II
Particle Board Characteristics Outer-Layer Resin A B C Standard Resin Resin Application, %
absol. dry/absol. dry wood 8 8 6 11 Particle Moisture, ~17.318.3 18.6 17.4 Flexural Strength, N/mm220.5 21.2 21.9 19.7 Swelling, ~
after 24 hours 9.6 9.5 9.6 9.6 _ It has thus been demonstrated that particle board prepared in accordance with the present invention has the same strength values as conventional panels, although noticeably less solid material and hence lower resin application is needed.
(D~ 71,200-DTA-160-F) BACKGROUND OF THE INVENTION
Outer layers of triple and multi-layer particle board are normally prepared using the same phenolic resin glues as in the center layers. Whilst the high reactivity of such 45 - 48 percent aqueous resins is highly efficient in the center layers, it causes embrittlement of the surface in the outer layers. Moreover, owing to the high alkalinity of such previously used resins which is required for the rapid setting of the center-layer, alkali-rich dust is obtained when grinding such particle board. On incineration this dust destroys the furnaces.
In view of the abov~e mentioned difficulties, special phenolic resins for the outer layers of particle boards were developed several years ago, which do not show the described disadvantages. The disadvantages were removed by lowering the alkali content of the 45 - 48 percent aqueous resins from 9 percent and also lowering the formaldehyde content in order to reduce the reactivity and to secure sufficient storage stability.
The phenol content in the resins was thus raised by about 40 percent. Hence the price of the new outer-layer resins and consequently of the particle board prepared therefrom increased appreciably, because the amount of solid resin applied to the particles cannot be lowered, despite -- 1 -- ~
qP
117~969 the higher phenol content in the resin solutions, in order not to deteri-orate the particle board properties.
In Federal Republic of Germany Patent Application No.
P 29 44 178.9-43, now Patent No. 2,944,178 issued on November 26, 1981 by the same inventors as herein and assigned to the same assignee, a process for producing multi-layer particle board was disclosed, in which the outer-layer particles are glued with a phenol formaldehyde resin having with a viscosity of 30 to 90 seconds (4-mm DIN cup), a solids content of between 30 and 41 percent, and an alkali content of less than 8 percent.
DESCRIPTION OF THE INVENTION
U.S. 3,968,308 discloses a process for the manufacture of chip boards using condensation resins and binders and product.
SUMMARY OF THE INVENTION
As a further development of the process according to Federal Republic of Germany Patent No. 2,944,178, a process is now disclosed for the manufacture of triple and multi-layer particle board in which the outer-layer particles are glued with a phenolic resin which has a miximum viscos-ity of 3000 mPas, a solids content of between 20 and 30 percent, preferably between 25 and 30 percent, and an alkali content of below 8 percent, pre-ferably between 2 and 6 percent.
It has been found that by molecular enlargement of such resins, outer-layer phenolic resins are obtained which present the known advantages of alkali-poor resins and, furthermore, have a noticeably better quality so that the solids content relative to the particle can be lowered , 117(~969 by 30 percent and more. Hence the novel outer-layer resins for particle board are obtained by condensation in order to form very large molecules, the alkali contents and the viscosities of the resin solutions remain virtually un-changed, namely 20 - 100 seconds, particularly 30 - 90 seconds and preferably 30 - 70 seconds (4-mm DIN cup).
These resins contain only 30 - 41 percent solids according to Federal Republic of Germany Patent No. 2,944,178 and now it has been found that they can contain as few as 20 - 30 percent solids, preferably 25 - 30 percent, instead of 45 -48 percent which is still customary. The lower storage stability due to the noticeably larger molecular structure can be offset by lowering the formaldehyde content in the resins. The formaldehyde content is thus dependent on the desired storage stability.
The solids content in a resin is defined as the residue obtained after evaporation of water and possibly low-molecular compounds under specified conditions (1 gram, 120C, 2 hours). As a rule the solids content in particle board binders is by 5 to 7 percent lower than the theoreti-cal value. This is mainly due to release of reaction water.
The phenol formaldehyde resin may be replaced Dy phenolic resins prepared from formaldehyde or other lower aldehydes with 1 to 4 carbon atoms and alkyl derivatives of phenol with 1 to 9, preferably 1 to 4 carbon atoms in the alkyl group.
The high quality of the new outer-layer resins allows lowering of the gluing factor, i.e. the amount of 117~969 solid resin required per absolutely dry particle, from the 10 to 12 percent previously used to 6 to 8 percent, without impairing the quality. The water content in the particle mat may result in higher or lower moisture of the glued particles depending on the solids content in the resin solution and the gluing factor at a given particle moisture.
For instance, a 37 percent resin (glue application 8 percent, 13.6 kgs moisture per 100 kgs of absolutely dry particle) corresponds to a conventional 45 percent phenolic resin (glue application 11.2 percent), and a 29 percent resin (glue application 6 percent, 14.7 kgs moisture per 100 kgs of absolutely dry particle) corresponds to a conventional 45 percent phenolic resin (glue application 12 percent~, respectively.
Qualitative evaluation of the novel high-molecular phenolic resins for use in the outer layers of particle board in comparison with a conventional 45 percent outer-layer phenolic resin was carried out employing three-layer particle board specimens, the center-layer particles of which had been glued with a conventional, alkali-rich 45 percent aqueous phenolic resin.
The superior quality of the new phenolic resins in the outer layers of particle board is clearly demonstrated by the following examples:
il7(~969 EXAMPLES
TABLE I
Composition of the Resins (Parts by Weight) Resin A B C Standard Resin Phenol 234 218 174 284 Formalin (37~) 403 394 300 547 Sodium Hydroxide Solution (50%) 98 93 58 94 Water 265 295 468 75 Characteristics Solids, ~ 37 35 27 45 Viscosity, seconds 43 35 41 45 (4-mm DIN cup) Gel Time, min. 27 21 24 25 (at 100 C) These resins can be manufactured in accordance with the known conventional processes.
Preparation of Outer-Layer Resin A
Pour 234 parts of phenol and 403 parts of ormalin (37~) into a flask. Heat to 70C. Add 98 parts of sodium hydroxide solution (50%) within a period of 60 minutes.
Charge 265 parts of water and raise the temperature to 80C.
Cool the product when a viscosity of 35 seconds (4-mm DIN
cup) is attained.
The outer-layer resins B and C as well as the standard resin were prepared accordingly.
117(~969 Pre aration of the Center-LaYer Resin p Pour 203 parts by weight of phenol and 463 parts by weight of formalin (37~) into a flask. Heat to 80C.
Add 98 parts by weight of sodium hydroxide solution (50%) to the reaction mixture within a period of two hours. Cool the resin solution to 70C. When a viscosity of 50 seconds (8-mm DIN cup) is attained, dilute with 174 parts of sodium hydroxide solution (50%) and 62 parts of water. Cool the resin.
This 45 percent was employed as a center-layer binder in the experiments.
The resins were tested in 16-mm thick three-layer particle board. The outer layertcenter layer particle ratio in the test specimens was 35:65. The glue application to the particles which had been dried to lower the moisture to approximately 5 percent was 8 percent solids, relative to absolutely dry wood for the resins A and ~, 6 percent for resin C, and 11 percent for the standard resin~ In each of the cases the center-layer particles were glued with 8 percent solids of a conventional, alkali-rich phenolic resin. The moisture of the glued center-layer particles was 11.6 percent prior to pressing.
In each of the cases the particles were waterproofed with 1 percent paraffin relative to absolutely dry wood.
The particle mats were pressed for four minutes at 180C. The gross density- of the particle board thus prepared ranged between 680 and 690 kgs/m3.
1~7096'~}
TABLE II
Particle Board Characteristics Outer-Layer Resin A B C Standard Resin Resin Application, %
absol. dry/absol. dry wood 8 8 6 11 Particle Moisture, ~17.318.3 18.6 17.4 Flexural Strength, N/mm220.5 21.2 21.9 19.7 Swelling, ~
after 24 hours 9.6 9.5 9.6 9.6 _ It has thus been demonstrated that particle board prepared in accordance with the present invention has the same strength values as conventional panels, although noticeably less solid material and hence lower resin application is needed.
Claims
1. A process for producing the outer layers of multi-layer particle board comprising the steps of gluing particles together with a phenolic resin having a maximum viscosity of 3,000 mPas, an alkali content below 8 percent and a solids content of between 20 and 30 percent.
2. The process of claim 1 wherein said phenolic resin has a solid content of between 25 and 30 percent and, an alkali content of between 2 and 6 percent.
3. The process of claim 1 wherein said phenolic resin is prepared from lower aldehydes having 1 to 4 carbon atoms.
4. The process of claim 3 wherein said aldehyde is formaldehyde.
5. The process of claim 3 wherein said phenolic resin is prepared from alkyl derivatives of phenol having 1 to 9 carbon atoms in the alkyl group.
6. The process of claim 1 wherein said particles comprise wood.
7. A particle board formed by the process of
claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19813115846 DE3115846C2 (en) | 1979-11-02 | 1981-04-21 | Process for the production of three-layer and multi-layer chipboard using phenol-formaldehyde cover layer resins |
| DEP3115846.3-15 | 1981-04-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1170969A true CA1170969A (en) | 1984-07-17 |
Family
ID=6130524
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000400715A Expired CA1170969A (en) | 1981-04-21 | 1982-04-08 | Process for producing multilayer particleboard |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0063770A3 (en) |
| JP (1) | JPS57181860A (en) |
| CA (1) | CA1170969A (en) |
| DK (1) | DK175982A (en) |
| FI (1) | FI821242L (en) |
| NO (1) | NO821227L (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2620288A (en) * | 1949-08-15 | 1952-12-02 | Dow Chemical Co | Adhesive comprising a mixture of a nucleated and nonnucleated phenolic resins |
| US3968294A (en) * | 1974-04-03 | 1976-07-06 | Chembond Corporation | Lignocellulosic particle board cured with alkali- and acid-catalyzed phenol aldehyde thermosetting resins |
| DE2724439B2 (en) * | 1977-05-31 | 1979-11-15 | Deutsche Novopan Gmbh, 3400 Goettingen | Process for the production of formaldehyde-free chipboard |
| DE3063263D1 (en) * | 1979-04-23 | 1983-07-07 | Oesterr Hiag Werke Ag | Wood chip board and process for its production |
| DE2944178C1 (en) * | 1979-11-02 | 1981-11-26 | Deutsche Texaco Ag, 2000 Hamburg | Process for the production of three and multi-layer chipboard |
-
1982
- 1982-04-07 FI FI821242A patent/FI821242L/en not_active Application Discontinuation
- 1982-04-08 CA CA000400715A patent/CA1170969A/en not_active Expired
- 1982-04-14 NO NO821227A patent/NO821227L/en unknown
- 1982-04-19 EP EP82103267A patent/EP0063770A3/en not_active Withdrawn
- 1982-04-20 DK DK175982A patent/DK175982A/en not_active Application Discontinuation
- 1982-04-20 JP JP57064877A patent/JPS57181860A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57181860A (en) | 1982-11-09 |
| FI821242A0 (en) | 1982-04-07 |
| FI821242L (en) | 1982-10-22 |
| EP0063770A3 (en) | 1983-03-16 |
| NO821227L (en) | 1982-10-22 |
| EP0063770A2 (en) | 1982-11-03 |
| DK175982A (en) | 1982-10-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4935457A (en) | Fiberboard method and composition | |
| US6747076B2 (en) | Furfuryl alcohol and lignin adhesive composition | |
| JP2656229B2 (en) | Composition for producing strand board | |
| US4409293A (en) | Wood composites of low formaldehyde emission | |
| US5011886A (en) | Process for producing modified phenolic resin bonding agents and use thereof for producing particle board | |
| US3968294A (en) | Lignocellulosic particle board cured with alkali- and acid-catalyzed phenol aldehyde thermosetting resins | |
| US5254639A (en) | Binding agents | |
| AU605504B2 (en) | Process for the preparation of urea-formaldehyde resins | |
| CA1290085C (en) | Substitute for amino and phenolic resins | |
| US4831089A (en) | Method for the production of amino resin | |
| EP0277106B1 (en) | Amino resin and a method for its production | |
| CA1038744A (en) | Process for the manufacture of chip boards using condensation resins as binders and product | |
| CA2088885C (en) | Precure resistant thermoset resin for molded wood composites | |
| CA1168144A (en) | Process for the manufacture of multi-layer particle board | |
| CA1170969A (en) | Process for producing multilayer particleboard | |
| US4201851A (en) | Organic phenol extract compositions of pecan pith agricultural residues and method | |
| US3287479A (en) | Method of preparing a wood particle board | |
| US4044087A (en) | Method of making fast cured lignocellulosic particle board | |
| US4200723A (en) | Organic phenol extract compositions of peanut hull agricultural residues and method | |
| US5074946A (en) | Wood bending methods employing fast curing phenolic resins | |
| CA1108126A (en) | Agricultural residue extracts and their use | |
| US4469858A (en) | Tree foliage extracts and their use in phenol-aldehyde resins | |
| US4579892A (en) | NH4 SSL-PF thermosetting resin and method of binding lignocellulosic material employing same | |
| US4170611A (en) | Process for preparing bonding agents for light-colored weatherproof wood materials | |
| US4069276A (en) | Low-pressure, no-cool phenolic type resin for decorative laminates |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |