GB2196342A - Manufacture of fibreboard - Google Patents
Manufacture of fibreboard Download PDFInfo
- Publication number
- GB2196342A GB2196342A GB08724097A GB8724097A GB2196342A GB 2196342 A GB2196342 A GB 2196342A GB 08724097 A GB08724097 A GB 08724097A GB 8724097 A GB8724097 A GB 8724097A GB 2196342 A GB2196342 A GB 2196342A
- Authority
- GB
- United Kingdom
- Prior art keywords
- urea
- formaldehyde
- resin
- solution
- weight
- 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
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims abstract description 76
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000004202 carbamide Substances 0.000 claims abstract description 42
- 229920001730 Moisture cure polyurethane Polymers 0.000 claims abstract description 21
- 239000002952 polymeric resin Substances 0.000 claims abstract description 12
- 229920003043 Cellulose fiber Polymers 0.000 claims abstract description 11
- 229920001807 Urea-formaldehyde Polymers 0.000 claims abstract description 10
- 238000000034 method Methods 0.000 claims abstract description 10
- 239000000463 material Substances 0.000 claims abstract description 8
- 238000002156 mixing Methods 0.000 claims abstract description 8
- 239000000203 mixture Substances 0.000 claims abstract description 7
- 238000007731 hot pressing Methods 0.000 claims abstract description 6
- ODGAOXROABLFNM-UHFFFAOYSA-N polynoxylin Chemical compound O=C.NC(N)=O ODGAOXROABLFNM-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000002131 composite material Substances 0.000 claims abstract description 5
- 229920002522 Wood fibre Polymers 0.000 claims description 7
- 239000002023 wood Substances 0.000 claims description 2
- 229920005989 resin Polymers 0.000 description 22
- 239000011347 resin Substances 0.000 description 22
- 239000000243 solution Substances 0.000 description 17
- 239000000835 fiber Substances 0.000 description 9
- 239000007787 solid Substances 0.000 description 8
- 239000011230 binding agent Substances 0.000 description 7
- 238000001816 cooling Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- GZCGUPFRVQAUEE-SLPGGIOYSA-N aldehydo-D-glucose Chemical compound OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C=O GZCGUPFRVQAUEE-SLPGGIOYSA-N 0.000 description 3
- 238000003825 pressing Methods 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000004821 distillation Methods 0.000 description 2
- 239000000839 emulsion Substances 0.000 description 2
- 230000003472 neutralizing effect Effects 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000008098 formaldehyde solution Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 235000011121 sodium hydroxide Nutrition 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
- C08L61/20—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen
- C08L61/22—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with acyclic or carbocyclic compounds
- C08L61/24—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with acyclic or carbocyclic compounds with urea or thiourea
-
- 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
- B27N1/00—Pretreatment of moulding material
- B27N1/003—Pretreatment of moulding material for reducing formaldehyde gas emission
-
- 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
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Wood Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Forests & Forestry (AREA)
- Dry Formation Of Fiberboard And The Like (AREA)
- Reinforced Plastic Materials (AREA)
Abstract
A cellulose fibre composite is manufactured by a method comprising blending together a urea- formaldehyde pre-polymer resin having a high formaldehyde:urea mole ratio, a particulate cellulose fibre material and a urea solution. The blend is then subjected to hot pressing to give fibreboard with low free formaldehyde content yet good physical strength.
Description
SPECIFICATION
Manufacture of fibreboard
The present invention relates to the manufacture of cellulose fibre-based composites, e.g. particleboard and medium density fibreboard, using urea-formaldehyde resins as binders.
In the production of such compositions using urea-formaldehyde resin binders, the small amounts of formaldehyde retained in the board after manufacture can cause environmental problems at some later date. It is therefore desirable to minimise this free formaldehyde content as much as possible without sacrificing the advantages that are achieved from the use of ureaformaldehyde resin binders. Many ways of solving the problem have been proposed and the approach most commonly used in the industry is to reduce the formaldehyde:urea mole ratio in the resin. Although this solves the particular problem of free formaldehyde in the product, it unfortunately causes reduced reactivity, reduced bonding efficiency and reduced storage stability of the resin.Reduced bonding efficiency in the product is displayed as reduced physical strengths in the board and as increased swelling of the board on being immersed in water or on being subjected to conditions of high humidity.
The present invention is based on the discovery that the above problems of the prior art can be avoided by the addition of a urea solution to the urea-formaldehyde resin binder prior to the hot pressing stage of the resin/fibre mixture. Accordingly, the present invention provides a method of manufacturing a cellulose fibre composite comprising blending together a urea-formaldehyde pre-polymer resin having a high formaldehyde: urea mole ratio, a particulate cellulose fibre material and a urea solution, and subjecting the mixture obtained to hot pressing.
Typically the particulate cellulose fibre material used in the present invention will comprise any of the materials conventionally used in the manufacture of cellulose fibre composites. In particular, we have achieved good results using wood chips and medium density wood fibres. The use of a high formaldehyde ratio resin blended simultaneously with urea solution and wood fibres has been found to give the following advantages over the use of a resin of equivalent final molar ratio:
(a) improved storage life of resin pre-polymer compared with conventionally used resins;
(b) lower formaldehyde emission for finished board;
(c) improved tensile strengths perpendicular to the plane of the board (i.e. known as "internal bond").
The urea-formaldehyde pre-polymer resins useful in the present invention have a high formaldehyde:urea mole ratio. By "high formaldehyde:mole ratio" we mean a formaldehyde:urea mole ratio of not less than 1.8:1. Typically, the urea:formaldehyde prepolymer resin used in the present invention will have a molar ratio of formaldehyde:urea of from 1.8 to 3.5:1 and preferably about 2.5:1. The pre-polymer resin will generally have a pH value in the range of 6.5 to 9.0 in order that it has good storage stability. Preferably, the pH of the pre-polymer resin will have a value in the range of from 7.0 to 8.0. The solids content and the viscosity of the prepolymer resin are not critical to the working of the present invention.However, the pre-polymer resin will generally have a solids content of from 55 to 70% by weight and a viscosity in the range of from 500 to 5000 cP at 25"C.
According to the present invention urea, as an aqueous solution, is added to the high formaldehyde resin in an amount sufficient to give a final formaldehyde: urea molar ratio of typically from 1.1-1.6:1, preferably about 1.2:1. The concentration of urea in the aqueous urea solution is not critical to the working of the invention although in practice it will be adjusted to give a convenient quantity of addition. A 50% (by weight) concentration of urea will normally be convenient. For a 50% urea solution, a typical quantity of addition is from 20 to 50% based on the amount of pre-polymer resin and depending on the mole ratio of the pre-polymer and the final mole ratio required. Other additives, such as wax emulsion conventionally used to improve hydrophobicity, may also be incorporated with the components mentioned above.
In general, the resin will be used in an amount to give a % resin solids (based on the weight of dry fibre) in the range of from 8 to 10%, preferably 6 to 8%.
The method of the invention is particularly suitable for the manufacture of medium density fibre (MDF) board where the resin is added to the wood fibre by "blow line" blending. Preferably the pre-polymer solution, the urea solution and a wax emulsion are metered separately through metering pumps and introduced simultaneously into a static mixer. The mixture is then flowed to the chip blender or, if appropriate, the blow line. In the case of blow line blending, it is also possible to meter the urea components directly into the blow line without the use of a static mixer.
The mixture of prepolymer, particulate cellulose fibre material and urea solution obtained by blending the components together is subjected to hot pressing. Hot pressing techniques are, of course, well known in the art and do not require detailed discussion here. Generally, however, pressing temperatures in the range of from 1500 to 2200C, preferably from 1 7or to 200"C, will
be used. The moisture content of the material prior to pressing will usually be in the range of from 7 to 14% and more usually from 9 to 12%. Pressure will be varied throughout the
pressing cycle, up to a maximum of about 400 psi, to produce fibreboard of a typical density,
of 600-800 Kg/m3, preferably 680-750 Kg/m3.
EXAMPLE I
A pre-polymer resin I was prepared by acidifying 20009 of a 50% (by volume) aqueous
solution of formaldehyde with a 50% (by volume) sulphuric acid solution to give a pH of 1.8.
This solution was heated to 60"C and 7809 of urea was added slowly allowing temperature to
rise to 850C. After neutralising with 32% (by weight) caustic soda solution to a pH of 7.0-7.4 the resin was distilled under vacuum at 60 C to remove 4009 distillate, finally cooling to 25"C or
below. This pre-polymer solution had a viscosity of approximately 200cP at 25"C and a solids content after drying for 3 hours at 120"C of 60% by weight and a molar ratio of formaldehyde to urea of 2.55:1.
A resin II was made using the same quantities and process as above but after distillation the
resin was cooled to 50"C and a further 8869 urea were added and allowed to react for 1 hour at 40"C prior to cooling to 25"C.
MDF boards were made using blow line mixing of resin and fibre. In the case of pre-polymer I, the flow rates of fibre, pre-polymer I and 50% urea solution were set to give the ratios:fibre 90 parts by weight, pre-polymer 1 10.9 parts by weight, 50% (by weight) urea solution 8.2 parts by weight-equivalent to 10% binder solids on dry fibre. In the case of resin II, the flow rates were set to give the ratios: fibre 90 parts by weight and resin 11 15 parts by weight again giving
10% binder solids on dry fibre. In both cases fibres were dried to 10% moisture content, formed into a mat and hot pressed for 3 minutes at 1700C to give a 12mm thick MDF board of about 750Kg/m3 density.Duplicate boards were tested and the following results obtained: Internal Total Extractable
Bond Formaldehyde
Density MPa mg/100g
Pre-polymer I+urea 760 0.66 3
Pre-polymer l+urea 750 0.61 10
Resin II 750 0.60 20
Resin Il 740 0.52 16
EXAMPLE II
A pre-polymer Ill was made by adding 9109 urea to 20009 50% (by volume) formaldehyde solution at a pH of 7.0-7.2, heating for 10 minutes at 100"C, dropping pH to 5-6 and reacting until a viscosity of 80cSt @ 25"C was reached, neutralising to pH 7.0-7.5 and distilling at 60"C to remove 3009 of water.The resulting pre-polymer resin solution had a viscosity of 200cPs @ 20"C and a solids content of 60% by weight. A similar resin was made but after distillation and cooling to 50"C a further 6209 urea was added and reacted at 40"C for one hour before finally cooling to 180cP at 20 C and a solids content of 65% by weight.
MDF boards were made by simultaneously mechanically blending dried wood fibres with prepolymer Ill and a 50% (by weight) urea solution in the ratio:wood fibre 90 parts by weight, prepolymer lit 11 parts by weight and 50% urea solution 8 parts by weight and similar boards were made using wood fibre 90 parts by weight and resin IV 15 parts by weight. In both cases, a total binder content of 10% was used and boards were pressed at 170 C for three minutes. The following results were obtained:
Internal Total extractable
Density Bond formaldehyde
kg/m3 MPa mg/1009
Board made with pre-polymer Ill +urea 760 0.52 48
Board made with resin IV. 740 0.43 77
Claims (7)
1. A method of manufacturing a cellulose fibre composite comprising blending together a urea-formaldehyde pre-polymer resin having a high formaldehyde:urea mole ratio, a particulate cellulose fibre material and a urea solution, and subjecting the mixture obtained to hot pressing.
2. A method according to claim 1, wherein the urea-formaldehyde pre-polymer resin has a formaldehyde:urea molar ratio in the range of from 1.8:1 to 3.5:1.
3. A method according to claim 2, wherein the urea-formaldehyde pre-polymer resin has a formaldehyde: urea molar ratio of about 2.5:1.
4. A method according to any one of claims 1 to 3, wherein the urea solution is added in an amount sufficient to give a final formaldehyde: urea molar ratio in the range of from 1.1:1 to 1.6:1.
5. A method according to claim 4, wherein the urea solution is added in an amount sufficient to give a final formaldehyde: urea molar ratio of about 1.2:1.
6. A method according to any one of claims 1 to 5, wherein the urea solution has a urea concentration of about 50% by weight.
7. A method according to any one of claims 1 to 6, wherein the particulate cellulose fibre material is selected from wood chips and medium density wood fibres.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB868624557A GB8624557D0 (en) | 1986-10-14 | 1986-10-14 | Manufacture of fibreboard |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8724097D0 GB8724097D0 (en) | 1987-11-18 |
| GB2196342A true GB2196342A (en) | 1988-04-27 |
| GB2196342B GB2196342B (en) | 1990-06-27 |
Family
ID=10605691
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB868624557A Pending GB8624557D0 (en) | 1986-10-14 | 1986-10-14 | Manufacture of fibreboard |
| GB8724097A Expired - Lifetime GB2196342B (en) | 1986-10-14 | 1987-10-14 | Manufacture of fibreboard |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB868624557A Pending GB8624557D0 (en) | 1986-10-14 | 1986-10-14 | Manufacture of fibreboard |
Country Status (3)
| Country | Link |
|---|---|
| ES (1) | ES2005034A6 (en) |
| GB (2) | GB8624557D0 (en) |
| IE (1) | IE60045B1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1992008588A1 (en) * | 1990-11-12 | 1992-05-29 | Derek Worthington Maude | Method and apparatus for producing insulation materials |
| US20180362405A1 (en) * | 2015-12-03 | 2018-12-20 | Kyoto University | Resin composition and method for producing same |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB979757A (en) * | 1962-09-05 | 1965-01-06 | Allied Chem | Improvements in or relating to bonding of materials together by means of urea-formaldehyde adhesives |
| GB1014961A (en) * | 1963-07-15 | 1965-12-31 | Ciba Ltd | Improvements in or relating to the manufacture of particle boards |
| GB1228954A (en) * | 1967-04-14 | 1971-04-21 | ||
| US4175150A (en) * | 1976-11-05 | 1979-11-20 | Masonite Corporation | Urea containing high density skin fiberboard with a low density core |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2039919B (en) * | 1978-07-06 | 1983-02-09 | Akesson A | Method of manufacturing bonded products of cellulose or cellulose derivatives |
-
1986
- 1986-10-14 GB GB868624557A patent/GB8624557D0/en active Pending
-
1987
- 1987-10-13 ES ES8702910A patent/ES2005034A6/en not_active Expired
- 1987-10-13 IE IE274787A patent/IE60045B1/en not_active IP Right Cessation
- 1987-10-14 GB GB8724097A patent/GB2196342B/en not_active Expired - Lifetime
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB979757A (en) * | 1962-09-05 | 1965-01-06 | Allied Chem | Improvements in or relating to bonding of materials together by means of urea-formaldehyde adhesives |
| GB1014961A (en) * | 1963-07-15 | 1965-12-31 | Ciba Ltd | Improvements in or relating to the manufacture of particle boards |
| GB1228954A (en) * | 1967-04-14 | 1971-04-21 | ||
| US4175150A (en) * | 1976-11-05 | 1979-11-20 | Masonite Corporation | Urea containing high density skin fiberboard with a low density core |
Non-Patent Citations (1)
| Title |
|---|
| WO 80/00142 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1992008588A1 (en) * | 1990-11-12 | 1992-05-29 | Derek Worthington Maude | Method and apparatus for producing insulation materials |
| US20180362405A1 (en) * | 2015-12-03 | 2018-12-20 | Kyoto University | Resin composition and method for producing same |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2196342B (en) | 1990-06-27 |
| IE872747L (en) | 1988-04-14 |
| IE60045B1 (en) | 1994-05-18 |
| GB8724097D0 (en) | 1987-11-18 |
| ES2005034A6 (en) | 1989-02-16 |
| GB8624557D0 (en) | 1986-11-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2602298B1 (en) | Use of a silane-containing binder for composite materials | |
| Younesi-Kordkheili et al. | Improving urea formaldehyde resin properties by glyoxalated soda bagasse lignin | |
| US4968772A (en) | Process for the preparation of urea-formaldehyde resins | |
| US4510278A (en) | Manufacture of chipboard and a novel suitable bonding agent | |
| US4828643A (en) | Liquified cellulosic fiber, resin binders and articles manufactured therewith, and method of manufacturing same | |
| US4303562A (en) | Lignin-containing resin adhesive | |
| US4362827A (en) | Manufacture of chipboard | |
| FI79332B (en) | FOERFARANDE FOER FRAMSTAELLNING AV ETT UREA-FORMALDEHYDHARTS SOM HAR ETT MYCKET LAOGT MOLFOERHALLANDE AV FORMALDEHYD TILL UREA. | |
| JPS61102213A (en) | How to make particle or fiberboard | |
| US8088881B2 (en) | Storage stable melamine-urea-formaldehyde resins and applications thereof | |
| US4968773A (en) | Process for the preparation of urea-formaldehyde resins | |
| US4831089A (en) | Method for the production of amino resin | |
| US5847058A (en) | Alkylresorcinol modified phenol-aldehyde resol resin and binder system, and method of making same | |
| US5162462A (en) | Process for the preparation of aminoplastic resin for use in the production of particle boards with low formaldehyde emission | |
| GB2196342A (en) | Manufacture of fibreboard | |
| EP0472257B1 (en) | Glutaraldehyde resin binding system for manufacture of wood products | |
| CN117402575A (en) | Preparation method of urea-formaldehyde resin adhesive | |
| CA1122508A (en) | Wood composites with foliage adhesive | |
| CA1190372A (en) | Process for the manufacture of lignocellulosic material fibreboard | |
| US20230193092A1 (en) | Blended furnish with improved performance and methods of making and using the same | |
| RU1778123C (en) | Composition for wooden fiberboards | |
| SU1416499A1 (en) | Composition for manufacturing particle-board | |
| IE60577B1 (en) | Process for the preparation of urea-formaldehyde resins | |
| FI72366B (en) | FRAMEWORK FOR FRAMING REQUIREMENTS. | |
| EP4665810A1 (en) | Blended furnish with improved performance and methods of making and using the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20041014 |