SE446987B - BINDING MATERIALS FOR THREE AND FIBER BASED MATERIALS OF PHENOL-FORMAL HEADS AND FRACTURED SIMILAR DERIVATIVES AND PROCEDURE FOR MANUFACTURING THE BINDING AGENT - Google Patents

Description

446 987 2 used in the manufacture of binder according to the latter The invention has more than 50% higher molecular weight than 5000. Such binder derivatives produced by Frak Fra onaëde lignin derivatives means have Vis Si t Si9VHFêaVS @ ëff superior to previous utav lignin derivatives produced binders in terms of their weather properties in particular, while their strength properties fully corresponds to the strength properties of commercial phenolic formaldehyde resin adhesive.

The above binders, of which the lignin derivatives more than 50% have a molecular weight higher than 5000, are prepared from weight fractionated lignhmeñvater obtained11n¿r ce11u1 ° sak ° kning_ Fractionation is usually performed by ultrafiltration of the liquor after cooking using a semipermeable membrane. Other kinds of fractionation processes have been described i.a. in Finnish patents ana fi kan nr. 3626/72.

In the efforts to develop the above-mentioned fractionated lignin derivatives produced the binders to become suitable for industrial trial production on a large scale is that in the production of the binder indispensable, abundantly high-molecular lignin derivatives containing fraction a relatively small part of the dry matter in the liquor from cellulose cooking, in that e.g. of the alkali lignins obtained is kept out of sulphate boiling usually only approx. 25-30% by weight own one molecular weight higher than sooo. : fan man strives asfhän at: av aa un preparation of the binder use Iïgünde fl vatenm more than 50 weight% skallzha molecular weight higher than 5000, comes only a small part of the final dry matter of the liquor for use, which reduces the significance of the invention in terms of total of liquor and wood.

The binder is prepared by mixing fractionated lignin derivatives. and phenol-formaldehyde resin. The phenol-formaldehyde resin prepared set in bricks of phenol and formaldehyde. Abundant use of formaldehyde promotes the formation of methylol groups in phenol-formaldehyde Hydra-rich abundance of methylol groups in phenol-formaldehyde Iwrtser is in favor of that of fractionated lignmer derivatives produced the binder, because it is likely that precisely these groups react with the lignin derivatives. However, it should be noted that abundant use of formaldehyde in the production of phenolic formaldehyde causes agg the phenol-formaldehyde resin produced contains plenty of free formaldehyde, which due to formal L, - 446 987 s The volatility and toxicity of dehydration are dangerous from worker safety point of view. Use of such a free formaldehyde containing phenol-formaldehyde resin as a component of a binder is therefore less advisable and has been banned in several countries.

The present invention has for its object to remedy the above-mentioned the disadvantages. The circumstances of the invention has been set out in the claims.

The invention is based on the surprising, in recent studies observed the fact that out of fractionated lignin of which at least 35% by weight, preferably 40% by weight, has a molecular weight above 5000 can produce a weatherproof binder agents with excellent strength for use in the manufacture of veneer, chipboard and fibreboard and similar products. In the future the position of the phenol-formaldehyde resin used in the binder phenol and formaldehyde are used advantageously in molar ratio between 1: 1.8 and 1: 3.

Thanks to the invention, the lignin derivatives only need to be fractionated to the extent that at least 35% by weight, preferably 40% by weight, of lignin the derivatives have a molecular weight higher than 5000. The preparation of the binder according to the invention is thus considerably more advantageous and cheaper compared to e.g. with the preparation of the binders as disclosed in Finnish Patents 51105 and 51946, to which lignin the derivatives used therein have had to be considerably fractionated longer, so that more than 50% by weight of said lignin derivatives have a molecular weight higher than 5000. The preparation of the invention the binder is due to the circumstances stated to be worth simpler and cheaper than the production of prior art binders of the same type.

The molecular weight distributions of alkali lignin can be determined using the gel chromatographic method, as indicated e.g. by Whitaker, J.R., Anal. Chem. ââ (1963): 12, 1950-1953, Forss, K.G. and Stenlund, B.G., Paperi ja Puu gå (1966): 9, 565-574 och 11, 673-676, and Forss, K.G., Stenlund, B.G. and Sågfors, P.-E., Applied Polymer Symposium No. 28 (1976), 1185-1194, John Wiley & Sons Inc. In these 446 987 4 procedures, the samples are eluted through a gel chromatography column. Mole- the cooling weight distributions are determined on the basis of the correlation between molecular weights and corresponding retention volumes. This correlated can be established by determining the molecules of different fractions. cooling weights using the light scattering method or using of osmometry or ultracentrifugation technology. These procedures are, however, extremely laborious and it is therefore with regard to practice more appropriate to calibrate the gel chromatography column using readily available substances that have known molecular weights.

Such a substance is e.g. glucagon, which has a molecular weight of 3483.

Thus, one can also compare the molecular weights of those in the binder use the lignin derivatives with glucagon. Accordingly, have more more than 40% by weight, preferably more than 45% by weight, of those According to the adhesive, the lignin derivatives use a molecular weight higher than glucagon.

The aqueous solution of the binder according to the invention has a pH of 8-14.

The lignin derivatives are used in the form of alkali or alkaline earth salts possibly containing an excess of the respective alkali.

The basicity of the binder is also favorable because a basic binder causes less corrosion than an acidic binder. The is also to be noted that when adding e.g. of sodium hydroxide to the binder, the sodium hydroxide lowers the viscosity of the binder. which facilitates the production of the binder and the treatment.

In a favorable embodiment of the invention, the binder contains urea 1-15% by weight, preferably 5-10% by weight, of phenol-formaldehyde the dry matter of the resin calculated. When mixing urea to the phenol-formaldehyde resin reacts with the urea with the excess formaldehyde and thus binds said formaldehyde present in the mixture. excess. Thus, the use of urea in the binder improves worker safety and enables the use of a binder strength properties improving formaldehyde excess in connection 446 987 5 with the preparation of the phenol-formaldehyde resin. Together with formal the dehyde forms urea a permanent polymerate and thus also increases the strength of the binder. in The lignin derivatives used in the preparation of the invention suitable adhesive can be e.g. alkali lignins obtained from alkalis boiling of a raw material containing lignocellulose, e.g. from the soda process (the boiling solution contains sodium hydroxide), sulphate process (the boiling solution contains sodium hydroxide, sodium sulfide and -hydrosulfide) or the oxygen-alkali process (the boiling is carried out with sodium hydroxide in the presence of oxygen).

The fractionation of the lignin derivatives can be performed according to any preferably a per se known fractionation process, such as by precipitation, the extraction method or ultrafiltration. Such fractions ionization procedures have been described i.a. in the U.S. Patent 3,825,526 and in Finnish patent application 3626/72.

The invention is described in detail below by means of exemplary embodiments and references to the accompanying drawings, in which: Figures 1 and 2 show the elution of the reference substances and internal standards by gel chromatography columns Sephadex G-75 and Sephadex G-50, determined by the absorbance at 280 nm.

Figures 3 and 4 show the logarithms of the molecular weights of the reference substances as function of relative retention volumes determined by elu- method and the light scattering method (LSA).

Fig. 5 shows unfractionated (A) and fractionated (B, C) D; alkali lignin gel chromatogram (sulfate boil by Scots Pine).

Fiq. 6 shows the cumulative molecular weight distributions, corresponding the chromatograms of Fig. 5.

The molecular weight distributions of the alkali lignins were determined in examples according to the following procedure: 446 987 The alkali lignin samples were analyzed by gel chromatography using of Sephadex columns (150 cm length, 1 cm diameter). The alkali lignins dissolved in sodium hydroxide-aqueous solution was eluted through a Sepha- dex G-50 column with NaOH (0.5 M) as eluent. The elution rate data-k to 20 ml / h. ' The concentration of the lignin in the eluent fractions was determined using of absorbance measurements (280 nm). The retention volume was determined by Weighing of the eluent fractions.

To achieve results that are independent of the gel filling density, a relative retention volume scale was introduced using two calibration substances such as internal standards. Retention volume peaks obtained with Blue Dextran (M = 2-106) was adopted as the first reference point in the scale with the value 0. The second reference point, rewarding value 1, was found by determining the retention peak obtained with sulfosalicylic acid (M = 218) (Fig. 1 - Sephadex G-75 and Fig. 2 - Sephadex G-50). ' The columns were calibrated by simultaneous determination of the the country of the molecular weight logarithm and the relative retention volume for readily available substances of known molecular weight. Seph fl dßx The G-50 column was calibrated using as a reference substance Cyto- chromium C, Glucagon and Bacitractin (M = 1423) and of NaOH (0.5 M3 as eluent (Figs. 2 and 4).

In this case, the lignin derivatives consist of faster than 9ïUka9 ° fl N " eluted through the gel chromatography column (lower relative retention volume) of molecules with a molecular weight higher than 3483 (Glükä90h) - Exemgel l Sulphate liquor obtained from pine sulphate boiling (Pinuß Silveßtriß) The dry matter content is 33%. »The solution had PH 12-7- The molecular weight distribution was determined using Sephadex The D-50 column according to the method described above. The chromato obtained the gram is reproduced in Pig. 6 (A). Molecular Weight Distribution, Pig. 7 (A), was calculated using the calibration curve shown in Fig. 4. 446 987 7 Accordingly, 25.3% by weight of the alkali lignins of the sulphate liquor had a molakylvixc higher an sooo aan 32.0 vika-e had an over: ass (glucagon). IN In the preparation of phenol-formaldehyde resin, molar ratios were used. country 1: 2, S between phenol and formaldehyde. The dry matter of the resin content was 46% and pH 11.1. The binder was prepared by mixing of the prepared phenolic resin (450 g) to the evaporated sulfate liquor (418 g). The mixture was stirred for 10 minutes and then after was added 132 g Filler mixture consisting of Ve fi emflöl (13 9) quebracho (32 g), chalk (61 g) and wood flour (26 g). The binder had a viscosity of 240 mPa.s and a pH of 12.1.

The binder was used for the manufacture of 3-ply birch veneer boards.

The application rate was 150 g / m2, the compression pressure was 0.7 MPa and pre-pressing time 6 min. The plates were hot pressed at 135 ° C, with the pressure 1.7 MPa; the pressing times used were 2, 3 and 4 min.

The properties of the plates were determined in the dry state and after cooking. in accordance with the Finnish plywood standard SFS 2416. The properties of these are given in Table 1, where each number is the value of five specimens.

Example 2 The sulfate effluent used in Example 1 was ultrafiltered, obtained an alkali lignin product, the molecular weight distribution of which has batch in Fig. 7, curve B (the gel chromatogram in Fig. 6, B). According thus, 30.9% by weight of the lignin derivatives had a higher molecular weight than 5000 and 40.0% by weight of one which was higher than 3483 (Glucagon).

The binder was prepared as in Example 1, using the same phenolic resin. The viscosity after filler addition was 320 mPa.s ..

Using the binder, 3-ply bear veneer patties were prepared under the same circumstances as in Example 1. The properties of the tiles have been presented in Table 1. 446 987 Exeyel 3. The ilignin product was isolated by ultrafiltration of a sulfur fatavlut. Its molecular weight distribution was determined by gel chromatography. fish, the chromatogram is seen in Fig. 6, C, and the molecular weight distribution Fig. 7, C. Accordingly, 36.0% of the sulfate lignins a momekyänkt higher am sooo sam: 46.5 weight-2 a moiekylviku over 3483 (Glucagon). The binder was prepared as in Example 1.

The viscosity of the binder was 420 mPa.s and the pH was 12.0.

Using the binary agent, 3-ply birch veneer tiles were made as in Example 1; the properties of the tiles are seen in Table lg Example 4 By ultrafiltration an alkali lignin fraction was prepared, the gel chromatogram is seen in Fig. 6, D, and the molecular weight distribution in Pig, 7, D. Accordingly, 43.2% by weight of the alkali lignins a molecular weight higher than S000 and 54.1% by weight had a higher molecular weight weight than 3483 (Glucagon). The drug was prepared according to Example 1; its viscosity was 470 mPa.s the pH 12.0.

Using the binder, 3-My birch veneer sheets were made as in Example 1. The properties of the tiles are given in Table 1.

Example 5 The sulfate liquor used in Example 1 was ultrafiltered, one alkali lignin fraction was obtained, warning gel chromatogram is shown in Fig. 6, E.

Its molecular weight distribution is shown in Fig. 7, E. Accordingly 46.9% by weight of the lignin derivatives had a molecular weight above 5000 and 57.7% by weight above 3483 (Glucagon).

The alkali lignin fraction was used to prepare the binder according to Example 1. The viscosity after refilling is 560 mPa.s And 11.9; Using the adhesive, 3-ply veneers were made as well Example 1. The properties of the tiles are shown in Table 1. ëššEEåš_É By ultrafiltrerixxg was isolated from the sulfate used in Example 1 completed a high molecular weight alkali lignin fraction whose gel chromatogram 6, F, and the molecular weight distribution in Figs. 7, F, according to whereby 53.4 'weight-ft of the alkali lignins had a higher molecular weight 5000 and 64.7 weight-So higher than 3483 (Glucagon). her. than The binder was prepared as in Example i. Its viscosity was Gao mPa.s via 2s ° c and pm 11.8. of 3-ply birch veneer tiles The binder was used for preparation The properties of the tiles under the same conditions as in Example 1. has been presented in Table l. 10 44-6 987 , ɧ§§1š_1. Comparison of the bonding properties of sulphate liquor and various alkali lignin fractions Example Press- In dry condition After cooking Nr nings- Shear- Crime Shear- Crime time holdf. by hå llf. through min N / mmz wood, 3 N / mmz wood,% l 2 1.80 57 0.55 B i 1.84 70 0.63 g 14 É 4 1.98 73 0.71 12 2 2 2.00 63 1.37 38 2.10 80 1.38 39 2.08 90 1.50 82 3 2 2.26 as 1.43 71 2.42 93 1.55 89 2.39 98 1.71 94 4 2 2.35_ 90 1.49 f 88 3 2.40 92 1.68 97 2.42 92 1.65 98 S 2.46 98 1.58 _ 90 2.55 96 1.63 93 2.43 99 1.70 96 6 2 2.57 100 1.65 99 2.60 100 1.76 100 2.58 98 1.72 92 According to the Finnish plywood standard SFS 2415, the shear strength in the dry state be at least 2.10 N / mmz, after boiling at least 1.40 N / mmz, and if the values are lower, break through the wood amount to at least 50%. In practice, however, considerably higher is required figures for breakage through the wood, or more than 80% even after cooking.

One observes when considering the properties of the tiles, which are shown 1 Table 1, that the requirements are met 1 examples 3-6 already with pressing times 2 and 3 min. The binder according to Example 2 over a longer pressing period for the claims to be complied with. 44a 93? ll Has Example 1 no longer helps to extend the pressing time: The line does not harden to water resistance šfäßfzíviffß. 1 ... 7 Na lignosulfonates of Na were used to prepare the binder which the Mw> 5000% by weight of the high molecular weight lignosulfonates glek to 61% and 72% by weight had a molecular weight higher than glucagon, Jun. over 3483. Aqueous solution of these lignosulfonates with 50% by weight had a viscosity above 80,000 mPa.s, the aqueous solution with 10% by weight mm pu s, 4.l The phenol formaldehyde resin used in the preparation of this binder position had been prepared by phenol and formaldehyde in molar ratio 1: 3 and the resin contained 3.4% free formaldehyde. In and for this removal, 8% by weight of urea / phenolic resin was added to the phenolic resin. fezmaldehyde cardiac substance. The mixture was stirred for 3 hours.

After 24 hours, the free formaldehyde was measured again. Formaldehyde- the content was now 0.1%. 417 g of phenol-formaldehyde treated in this way Hydrogen resin, which had a dry matter content of 48%, was added to a water. solution of the above dry matter Na lignosulfonates 32 2.

The mixture was stirred for 10 minutes and to this was added 26 g of sodium hydroxide solution with 50% by weight of dry matter content. Hereafter appointed 140 g of filler mixture containing 40% by weight of wheat flour, 24% by weight ï quebracho, 20 wt% ~% wood flour and 46 wt% chalk. The adhesive mixture had a viscosity of 800 mPa.s and a pH of 9.3.

The binder was used to make 15-ply mixed veneer sheets.

The application rate was 150 g / m2, the opening time 45 minutes, the time 6 min and the pressure 0.7 MPa. The plates were hot pressed at l30 ° c with pressure 1.37 MPa, pressing time 18 min. The plates' own are listed in Table 2, determined according to Finnish plywood standards. the SFS 2416 in the dry state even after boiling and soaking (each value is the mean value of the samples). ”- 446 98? Latte Glue joint In dry condition 20 h soaking Boiling f. z.

E- N / mm% N / mmz% .N / mmz% 1 surface 2.99 90 1.41 99 1.99 100 mitt 3.92 93 1.74 07 1.41 09 2 1 Yta 3.10 90 1.69 91 1.21 90 mitt 3.42 96 1.03 93 2.20 98 3 yta 3.09 99 1.72 94 1.22 91 Mint. 2.07 93 1.54 90 1.54 97 4 surface 3.61. 90 1.36 100g 1.69 92 Mit: 3.23 ss 1.65 93 1.72 av s - Surface 3.10 of 1.60 09 1.96 92 mic: 3.67 92 1.57 98 1.33 90 The plates well met the requirements set by Finnish standards. the SFS 2415, that skhwhå fl phase ten mten in the dry state should be 2.10 N / mmz, after boiling at 1.40 N / mmz and after boiling 1.60 N / mm2. If the shear strength values as stated above not achieved, breakage through the wood should amount to at least 50%.

HV Ylv Exemgel 8 As the raw material for the binder, sulphate lignin was used in which the high lecular (Mw> 5000), the weight fraction was 40% by weight of all lignin and 50% by weight had a molecular weight higher than glucagon.

The phenol-formaldehyde resin used was a product which had been prepared of phenol and formaldehyde 1 molar ratio 1: 2.5 and contained 2.1 weight% free formaldehyde. To the solution was added 3% by weight of urea / dry matter in the resin. The mixture was heated to 30 ° C and stirred. stirred for 3 hours. The formaldehyde content then decreased to 0.4 8.

The treated 46% phenol-formaldehyde resin (520 g) was mixed with moderate fat content (340 g) which had a dry matter content of 30 2.

The pH of the adhesive was 11.8 and the viscosity 160 mPa.s. Then added 26 987 13 in addition 140 q fylhmdelsbk fl mníng Hmehå fl ande wheat flour 14 Q, chalk 3 ”G, qußbrä fl h fl 35 and wood flour 35 g. Viscosity after 30 min blanåninq amounted to 640 mPa.s. The seed mixture was used to make 3-ply birch veneer. plates. The application rate was 150 g / m2, the pre-pressing time 5 min and the pressure 0.8 MPa. The plates were hot pressed at 135 ° C. at a pressure of 1.8 MPa. The pressing times were 2, 2 1/2, 3 and 4 min. the properties of the surfaces were determined as dry even after cooking.

In the table below (Table 3), each value is the mean of five plates, i.e. 25 test pieces, L¶§lL§¿ Properties of 3-ply birch veneer tiles Pressing time In dry condition After cooking (min) N / mm? % N / mmz% 2 3.31 93 - 1.58 Bl 2 1/2 2.95 100 1.62 92 3 3.os_ 98 1.88 94 å 3.21 97 1.66 92 Also for pressing times that were shorter than normal (2 and 2 1/2 min) good results were obtained with this bhmemedeh Example 9 For the preparation of the binder, alkali lignin in which they the weight fraction of high molecular weight (MW> 5000) was 48% of all lignin reefs and 59% by weight had a molecular weight higher than glucagon.

The phenol-formaldehyde resin had been prepared in molar ratio 1: 2.2 and contained 1.7% free formaldehyde. To the resin was added S% urea / resin dry matter. The mixture was stirred at room temperature. tour for 5 hours. After this, the free amount of formaldehyde had passed down to 0.08%. The resin-urea mixture was added to the alkali lignin solution with a dry content of 42% (432 g 51% resin / S24 g lig- solution). 50% sodium hydroxide solution was added.

The mixture was stirred for 30 minutes, the pH was 11.8. Vlsktßsïšßt flfl V81 'VW 25 ° C 320 mPa.s .. 14 446 98 Particleboard was prepared using the binder as prepared set. To this was then added an additional 10% paraffinic acid. emulsion, as a dry matter calculated on the glue dry substance. Using the binder, chipboards were made with 10, 20 ech 30 mm thick, with nominal bulk density 750 g / m3. Binder the amount injected into the chips amounted to 10% by weight calculated on dry matter. For the hot pressing of the chipboard, the combined contact and high frequency heating. Press plate tem- temperatures were 180 ° C and the pressing pressure 2.65 N / mmz. the times and properties of the plates are shown in the table below, Qabell 4. Properties of chipboard using combined contact and high frequency heating Flat- Use press- Bending- Tensile- Thick- V 100 thick- hold- hold- play- play 'ninqstid firmness firmness swell. 2 2 2 h 24 h mn min s / mm N / mm N / mm%% N / mm2 15 _ 4 1/2 2 18 '19.8 0.47 2.3 11.5 0.21 20 5 15 19.2 0:52 1.8 '1008 0.19 30 5 l / 2 ll I 19.2- 0.49 '2.2 ll.l 0.23 >,> <<> DIN 68761 = 17.7 = 0.34 = 6.0 = 12.0 = 0.l5 requirement - * The tiles fully complied with the requirements of the German standard DIN 68761 sets for phenol-glued chipboard. The plates were completely formal- hydreless after hot pressing.

Example 10 For the binder, a phenol-formaldehyde resin was prepared with molar portion pheno1: forma1dehyde 1: 3. After the preparation contained the 4.8% free formaldehyde. To the resin was added 10% urea and the mixture was stirred at 25 ° C for about 4 hours. The mixture got then stand for another day, after which the free formaldehyde is des. This had fallen to 0.1%.

The alkali lignin fraction whose properties were given in Example 9 was used to the preparation of the binder. To 640 g of alkali lignin solutions with a dry content of 42%, 360 g of the above-mentioned phenol-formaldehyde were added. 446 987 B urea resin, which had a dry content of 50 S. Lignin and pheno1formaldehyde ~ the proportion of the resin was 60:40. The banding agent had a pH of 11.0.

The binder was used to make formaldehyde-free chips. plates. É The amount of binder was 8% calculated as dry matter on the dry matter the weight of the shavings and 10% of the weight of the shavings. In the shavings were injected in addition 50% paraffin emulsion 1% dry matter on the dry traces weight. Using the adhesive, 15 mm s were prepared three-layer chipboard with a bulk density of 750 kg / m3. The press plates temperature was 215 ° C, compression pressure 2.94 MPa and pressing time 20 S / mm- After heating, harden the plates at 180 ° C.

The properties of the tiles are shown in Table 5.

Table 5. Properties of chipboard using post-curing Plate Thick- Volume weight Bending- Tensile- Thickness- V 100 No play strength.hâ11f. swelling mm kg / ms N / mmz N / mmz 2 h 24 h 2 %% N / mm 1 115.00 760 20.6 0.47 2.4 9.0 0.10 2 15.10 vss 20.3 0.46 2.s 10.2 0.19 3 1s.0s 750 20.5 '0.55 1.9' 10.5 0.21 4, 15.09 162 20.9 0.54 2.81 11.0 0.20 s 16.10 155 19.4 0.46 2.5 10.0 0.15 The plates met the requirements of DIN 68761. No formal dehyde odor was felt during the preparation and the formaldehyde was released not afterwards from the plates.

The viscosity values given in the working examples have been saturated Broofield viscometer, 25 ° C, 50 rpm.

The invention is of course not limited to the stated embodiments. examples, but without these intentions may vary. standing patent claims. 446 987 16 In this case, the dry weight ratio between those contained in the binder can the lignin derivatives and the phenol formaldehyde resin vary e.g. within limits 90:10 and 20:10. Furthermore, the phenol formal dehyd in the phenolic resin vary e.g. within limits 1: 1, 4 and 1: 3.

Furthermore, to the adhesive prepared with the binder, known per se fillers, such as chalk, wood flour, quebracho, wheat flour, etc.

Furthermore, urea can also be added to binders with another molecular weight distribution than that of the invention, for binding the amount of formaldehyde contained in them.

The improvement of moisture resistance and wet strength with binder according to the invention can in a conventional manner also is used for cardboard, whereby the binder is suitably added mass. The binder forms water-resistant bonds with cellulose. loose and polymerized into long chains, which form an interior network in the carton and gives the carton improved strength even in wet state.

When experimenting with cardboard, e.g. for use in packaging and the like, were obtained with adhesives according to the invention containing containing 70% phenol formaldehyde resin and 30% lignin an improvement of the wet tear strength by about 66% and the wet tensile strength by up to 90%.

Claims (7)

446 987 ”PATENT REQUIREMENTS Binders for the production of wood and fiber-based materials, such as veneer, chipboard and fibreboard, consisting of phenol-formaldehyde resin and molecular weight-derived lignin derivatives, characterized in that at least 35% by weight and less than 50% by weight of the used lignin derivatives have a molecular weight above 5000 and that more than 45% by weight and less than 61% by weight of the lignin derivatives used have a molecular weight above the molecular weight of glucagon, ie. above 3483, and that the lignin derivatives used are alkali lignins and that the phenol-formaldehyde resin is prepared from phenol and formaldehyde in a molar ratio between 1: 1.4 to 1: 3 and preferably between 1: 1.8 and 1: 3. Binder according to Claim 1, characterized in that the pH of the binder is 8-14. Binder according to Claim 1 or 2, characterized in that more than 40% by weight of the lignin derivatives used have a molecular weight higher than 5000. Binder according to one of Claims 1 to 3, characterized in that the lignin derivatives used are present in the form of a basic alkali metal salt. The binder contains urea 1-15% by weight, preferably 5-10% by weight, based on the amount of dry matter in the phenol-formaldehyde resin. 1 1 Binder according to one of Claims 1 to 4, Claims 1 to 1 in E A process for the preparation of a binder according to any one of claims 1-5, wherein the phenol-formaldehyde resin is mixed with molecular weight fractionated lignin derivatives for use as a gluing substance in the production of wood and fiber-based materials, such as veneer, shavings. and fibreboard as water mixture optionally together with fillers, characterized in that of the lignin derivatives mixed with the phenol formaldehyde resin at least 35% by weight and less than 50% by weight have a molecular weight above 5000, that more than 45% by weight and less than 61% by weight of the lignin derivatives used have a molecular weight above the molecular weight of glucagane} i.e. above 3483, that the pH of the binder is adjusted between 8 and 14, preferably 9-13, that the lignin derivatives used are alkali lignins and that the phenol-formaldehyde resin be prepared from phenol and formaldehyde in molar ratio 1: 1.4 to T: 3, preferably between 1: 1.8 and 1: 3. 7. Process according to claim 6, characterized in that urea is added to the phenol-formaldehyde resin 1-10% by weight, preferably 5-10% by weight, calculated on the dry matter amount of the resin.