SE425093B - PROCEDURE FOR PREPARING A GLUE OF UREAFORMAL HYDRAINIC RESIN, SULFIT LIT AND WATER - Google Patents

Description

fl wr vsoaosz-7 g ~ Willeger et al., U.S.A. Pat. No. 3,994,850 describes the manufacture of particle board, in which an adhesive produced by allowing urea, soda black liquor and formaldehyde to react with each other is used. o However, none of the above procedures has with any major success solved the problem of having a larger amount of sulphite liquor included as an ingredient in chipboard adhesives. It has become an axiom in the industry that the use of large quantities of these materials in the manufacture of such adhesives must be avoided because the resin components of the adhesives cannot react with each other and that chipboards made with such adhesives have properties which are not acceptable. I This view is based on the results of extensive experimental experience, and it is fully justified by the complicated molecular composition of the two interacting materials, i.e. the sulphite lute and the urea resin, as well as by the different chemical reactions which can potentially take place in the preparation of the resin, in the mixing of the resin with the sulphite lute and in the subsequent hot pressing operation.

Then e.g. sulfite liquor does not react with and is insoluble in some urea resins.

Under certain conditions, urea and formaldehyde can be combined with each other to form condensation products containing a high proportion of mono-, di- and polymethylolurea products, i.e. products rich in methylol. Under other conditions, urea and formaldehyde can be combined with each other to form methylene-rich products with a high content of methylene urea. The methylol-rich products can react with sulphite liquor, while the methylene-rich products cannot. Consequently, if one wants to successfully combine urea resin with sulfite liquor, then it must be the methylol rich type.

Second, if the urea resin is mixed with substantial quantities of untreated ammoniacalized sulfite liquor containing ammonium in the form of ammonium lignin sulfonate, "ammonium rapidly removes any free and loosely bound formaldehyde which may be present in or added to the urea resin, whereby it is converted to the relatively inactive product hexamethylenetetramine. This reaction releases excess lignin sulfonic acids, which lowers the pH of the adhesive mixture, over-catalyzes the adhesive and as a result results in excessively rapid curing and premature gel formation. Conversely, when the resin is mixed with calcium, magnesium or sodium alkalized sulphite liquor, no ammonium is present at all, the above-mentioned irrigation of lignin sulfonic acids ___..._.__...._.__. S ..... ..-.... s 7808082-7 does not take place and the glue is undercatalyzed.

Consequently, it is important that the ammonium content of the glue is carefully controlled.

Third, variations in the pH value of both the adhesive product and its components can significantly affect the strength and properties of the adhesive. An excessively high pH value causes the adhesive to cure too slowly. Too low a pH value causes it to cure too quickly. And in addition, excess acid during hot pressing can break down the cellulose content of the wood on which it is applied. For these reasons, it is necessary to carefully check the pH of both the sulphite lute and the urea resin components in the desired adhesive product.

The main object of the present invention is to provide a process for the production of an adhesive product suitable for the manufacture of wood products, which adhesive product comprises a large proportion of sulphite liquor from sulphite treatment of wood pulp, which is light and easy to manufacture, which can furthermore be used in the manufacture of ex-chipboard using conventional equipment and methods and which results in the production of glued wood products with commercially acceptable properties, which meet the marketing standards for such products, and are fully competitive with related products, produced using conventional, more expensive adhesive products.

Another important object of the invention is to provide a process or adhesive product, enabling the use of a large component of a very cheap waste product, sulphite liquor, whereby the classic problem of getting rid of the pulp mills' sulphate waste ends is partly solved while achieving economic advantages. in the manufacture of adhesives for particle board and similar products, which for example for a particle board factory of average size can mean a saving in the order of 2 mill. kroner per year.

The object of the invention is achieved by carrying out the method according to the features stated in claims 1-6.

In connection with the invention it has been discovered that the problems associated with the creation of a compound between urea resins and sulfite liquor in the manufacture of a useful adhesive product can be overcome and said object is achieved by producing an adhesive product which is substantially consists of SU to 90 parts by weight of ureahurts in solid form and from 10 to S0 parts by weight of sulphite waste liquor from the sulphite treatment of wood pulp based on the dry matter value of the sulphite liquor.

The adhesive product also contains a key component of from 0.2 to 4.0% by weight of ammonium ions (expressed as NH3) calculated on the dry matter base of the sulphite liquor. The ammonium ion can be supplied by using an ammoniacalized sulphite liquor with a carefully controlled content of ammonium ions. In case one would like to use another sulphite liquor, such as e.g. a calcium-, magnesium- or sodium-alkalized sulphite liquor, the ammonium ion can be added by adding a water-soluble ammonium salt of a strong acid in a suitable quantity.

The ammonium salt has the effect of providing ammonium which combines with free formaldehyde present in the mixture to form the neutral product hexamethylenetetramine which releases a strong acid and leaves a mixture of dextromaxo-controlled acidity which promotes the desired the condensation or polymerization of the adhesive product in its use, as mentioned above.

I The urea component of the adhesive product is characterized by a molar fraction ratio of formaldehyde to urea of from 1.0 to 1.8, and a methyloline content corresponding to a Wítte number of from 1.0 to 1.8. Hartset's properties are thus such that it is ensured that it can react with and achieve a desired degree of solubility in sulphite liquors to the same extent as is needed to produce a suitable adhesive product.

The adhesive product is manufactured by a simple mixing of the sulphite liquor with urea in the presence of ammonium ions under temperature conditions, with a pH and a viscosity which results in the preparation of a mixture in which the lignin sulphonic acid component of the sulphite liquor and urea condense to a considerable extent in a protracted course. The process and the product are thus to be regarded as different from previous methods and according to these products produced, in which such a continuous condensation takes place rapidly or intentionally accelerated. It must also be considered different from previous production methods, in which the sulphite liquor is reacted with urea and formaldehyde in a process with only these three components.

When the product prepared according to the invention is used in the manufacture of glued products as chipboard, the glue is simply added to the wood material in ordinary quantities and proportions, and a hot pressing takes place, conventional apparatus being used to form the final glued and compressed wood product. .

In the process according to the invention, the same was done so that the adhesive product described according to the process described here consists, expressed in parts by weight of dry matter, of a non-condensed mixture of the following: Urea 50 - 90 Sulphite waste liquids from sulphite-treated wood pulp 10 - 50 The adhesive product also contains from 0.2 to 4.0% by weight of ammonium ions (expressed as NH3) per dry matter weight of the sulphite liquor.

As also mentioned above, the urea resin is characterized by carefully controlled properties, especially by its molar ratio of formaldehyde to urea of from 1.0 to 1.8, its pH of from 6 to 8 and its methylol content corresponding to a Witte number. of from 1.0 to 1.8. In addition, the dry matter content should be from 50 to 72%, preferably from 55 to 65% by weight, and the viscosity should be from 50 to 250 centinoisos at a content of 65% dry matter resin and a temperature of 25 ° C.

Regarding the molar fraction ratio, it should be noted that if the molar fraction ratio is below 1, then the urea resin polymer is not sufficiently effective to develop the desired adhesion properties in the final product. At a molar fraction ratio above 1.8, an excessive excess of formaldehyde is present. This leads to the formation of an adhesive product, which has an unpleasant odor, and which releases too many toxic gases during hot pressing and later during use of the product.

Regarding the viscosity limit of 50 to 250 centipois, it should be noted that this range of variation is below the viscosity range of the urea resins commonly used in the manufacture of particle board. If the urea resin per se were used at the usual viscosity , the result would be unsatisfactory due to its poor adhesion properties. The addition of sulphite liquor in the manner emphasized here is needed to create the desired adhesion properties.

Regarding the methylol content of the urea resin, a content corresponding to a Witte number of 1.0 to 1.8 is necessary in order to react the urea resin with the sulphite lute and to achieve a satisfactory adhesion and product quality. 7808082-7 in ° Theoretically, an urca formaldehyde resin with such a low methylol content, represented by Wittetalct 1.0, would not have sufficiently high hydrophilicity to react with the sulfite lute. However, it can be reasonably assumed that the Wittet number measured at the first component, before any reaction with the second component is started, is not representative of the methylol content when the reaction is started.

Namely, it can be assumed that immediately after the reaction between the two components begins to open with such great speed (fractions of seconds) new hydrophilic groups not affecting the reaction before the reaction, so that the methylol content is sufficient for the intended reaction. In this case, the resin must contain ether compounds, which can be broken down into OH groups. This can be noticed by the fact that ether-rich resin products give a satisfactory result even at the lower value of the Witt number, while less ether-rich resins may require a higher Witt number in the initial state.

The white number is obtained as a result of a determination of the methylol groups in the urea resins by the reaction of the resins with 2,6-dimethyl-phenol- (2,6-xylenol). It indicates the methylol action of the resin. It is determined as follows.

A single solution of 2,6-dimethylphenol (25.0 g) in 200 ml of water containing 8.0 g of sodium hydroxide is treated with 12.5 g of the urea resin to be tested by making a proper mixture. The resulting reaction mixture is allowed to stand at room temperature in the dark for three days. Concentrated hydrochloric acid is added until the pH of the reaction mixture reaches 5.5 - 6.0. The reaction mixture is washed in a 1-liter bottle and steam distilled until 700-750 ml of distillate have been collected.

The condenser is rinsed with a little methylene chloride and the condensate is extracted with 3 x 100 ml of methylene chloride. The combined methylene chloride extracts are filtered through about 20 g of anhydrous sodium sulfate and the sodium sulfate is washed with 2 x 25 ml of methylene chloride.

The methylene chloride is evaporated off under vacuum until the weight of the evaporating bottle remains unchanged. The weight of the remaining 2,6-dimethylphenol is determined and its original weight is subtracted. The difference between the values of these two weights is the quantity of 2,6-dimethylphenol which has reacted with the urea resin and constitutes a measure of the methylol content in the resin. The value of this is here called Wittetalet. This value is calculated by the following equation: The weight of recycled Xylenol = - _ - 12.5 x percent of dry matter of urea-formaldehyde resin wf ?? e Éfleç? 7808082-7 This value is directly related to the motylol content in the resin, as shown by the following set of typical test results, in which Wittetalen was determined for series of urea-formaldehyde resins with varying molar ratios (moles of formaldehyde per mole of urea) prepared on such that the methylol strength became maximal.

Molar fraction ratio of uranium resin Hittgtgl 0.9 0.76 1.2 1.17 1.3 1.30 1.4 1.38 1.5 1.47 1.6 1.57 100% dimethylolurea 2.64 Regarding the sulphite liquor component in the adhesive product according to the invention, the following is stated: The term "sulphite waste liquor" means the liquid obtained by the conventional treatment of the pulp with acid sulphite, in which there is a total of about 5 to 7% by weight of sulfur dioxide and 0.9 to 1.2 per cent of sulfur dioxide, which has been combined.

The sulphite liquor is formed by any of the conventional methods of treating pulp with acid sulphite. Consequently, it may consist of any of the commonly produced waste shutters, i.e. either ammonia-catalyzed, calcium-, magnesium- or sodium-alkalised waste liquor.

A special exception, however, is the waste shutters obtained in the treatment of wood pulp with "Magnafite", "Sodafite" and by means of semi-chemical ("NSSC") processes with neutral sulphite. These three waste terminations are unsuitable for the purposes of the invention and are completely excluded from the description thereof, since they all contain in their concentrates considerable quantities of sulphite ion residues. As will be explained in more detail below, it would result in an unfavorable change of the pH value, if these liquors were used in the manufacture of the adhesive products described here.

The sulphite liquors can be used largely in the form in which they are obtained from the concentration process of the mill without first being sugared.

In the form in which the sulphite liquors are obtained, they generally have a dry matter content of from 40 to SS% by weight, usually 50% 1 2 t, a viscosity of, for example, from 500 to 4000 centipoise at 25 ° C and 50% concentration, and a pH of from , 5 to 4.5.

If the dry matter content is less than about 40% by weight, there will be too much water in the clutches to be really suitable for the manufacture of the adhesive products. If the sulphite liquor contains more than 55% dry matter, it is too viscous to be comfortable to handle in the factory.

The viscosity of the sulphite liquor should preferably be within a usable viscosity range, in which the sulphite liquor can be pumped at room temperature and can be easily mixed with the urea ore set. Higher viscosities can be controlled by heating the waste lids. This allows the use of sulphite liquor with viscosity values as high as 15,000 centipoise.

It should be mentioned that the proposed viscosity of resin and sulphite liquor makes suitable handling conditions for the components and a final product with desired properties. The latter, however, do not depend on the individual viscosity of the components but on the resulting water content. This can, as will be readily understood, be controlled per se by a deviation of the viscosity from the recommended values for one component by a change in the viscosity of the other component, or, in the event of too high a viscosity by adding water to the mixture. u The pH of the sulphite liquor should be in the range from 3 to 9.

If the pH value of the sulphite liquor is lower than 3, the adhesive in which it is a constituent hardens too quickly and gels too quickly at room temperature to be comfortable to handle. If the pH of the sulphite liquor is higher than 9, the adhesive product in which it constitutes a constituent is cured too slowly to find practicality. The sulphite liquor should preferably be substantially free of dissolved sulfur dioxide (sulphite ions), since the presence of this material as an end result, the pH value of the adhesive increases, so that it reaches a level at which the curing during hot pressing takes place too slowly, which adversely affects the production and properties of wood products made with such adhesive. The sulphite liquors, unless they have been neutralized, become free of sulfur dioxide, since this material is expelled in connection with the concentration of the sulphite liquor.

As discussed above, ammonium ions used in a proportion of 0.2 to 4.0% by weight (expressed as NH31 of dry matter of sulphite liquor) constitute a key component of the adhesive product according to the invention, and it is this which accounts for the successful This component of the mixture has the function described above to react with a portion of the formaldehyde to form the relatively inactive product hexamethylenetetramine, which results in a lowering of the pH. -value in the adhesive mixture, so that it comes down to a level where it hardens rapidly during hot pressing.

If too much ammonium ions are present, the resulting high ammonium content of the adhesive reacts rapidly with free or soluble formaldehyde in the urea resin, so that the stable hexamethylenetetramine is formed, and large quantities of strong acid are released.

These excess quantities of acid in turn lower the pH of the mixture and catalyze the urea resin, so that it undergoes a very rapid cure.

The effect of a fast-curing adhesive on the quality of the chipboard or wood product in question is that the surfaces become soft, and in general the strength properties decrease due to premature curing. Water absorption and swelling are also adversely affected.

The flowable state of the binder is severely limited in time and thus a serious risk of gel formation arises in the factory's pipelines and equipment.

The ammonium ion component of the mixture is included as the water-soluble ammonium salt of a strong inorganic or organic acid (ionization constant (Ka) of 10-3 or greater). Examples of such salts are: Ammonium lignin sulphonate Ammonium chloride Ammonium sulphate Monoammonium phosphate Ammonium oxalate Ammonium benzene sulphonate Ammonium acetate of monochloroacetic acid It is obvious that where the acidic sulphite liquor consists of an ammoniacal sulphyl sulfate, the sulphonate sulphonyl sulphonate in ammonium sulphonyl sulphate In this case, it is not necessary to add further thereof or any other ammonium salt.

Since the ammonium ion content of the sulphite liquor in fact usually exceeds what is permitted in the adhesive products described here, excess ammonium ions can be removed by treatment with a predetermined quantity of caustic soda or solid strong base, which expels ammonia and only leaves the desired content of ammonium ions in the form of a residue. The removal of excess ammonia with a base should be done after the sulfur dioxide (on the acidic side) has been removed in the manner described above. 7808Û82'7 g 10 If calcium, nmg fl câümv or sodium alkaliscradc sulphite liquors are used, add a sufficient number! of a ammonium compound to result in the formation of an adhesive product containing ammonium ions in the indicated proportion.

When composing the composition of adhesive products according to the invention by means of the above-mentioned primary components, it is stated that dosage components in predetermined quantities are simply mixed in a suitable mixing machine of conventional type, until a uniform mixture is obtained. The mixing is carried out at or near room temperature 100 to 30 ° C) to prevent condensation of the components of the sulphite liquor with the urea resin. The adhesive product according to the invention is largely uncondensed. The condensation of limmct takes place during the hot pressing in connection with the curing.

In view of what has been stated previously, the process according to the invention will be characterized in that as components are selected: 1) urea formaldehyde resin with the following properties: formaldehyde / urea ratio 1.0 - 1.8 pH '6 - 8 viscosity preferably in the range 50 - 250 centipoise (at 65% dry matter content and 25 ° C) wittecai 1.0 - 1.8 where the Witt number is an expression of the methylol content of the resin. in '2)' sulphite liquor having the following properties: pH 3,5 - 4,5 500 - 4000 centipoisc (at SO 0 dry matter content _ and 2506) With the liquor substantially free of loose sulfur dioxide.

The liquor is checked for its content of ammonium ions, which must be 0.2 - 4.0% by weight (expressed as NH3) calculated on the dry matter weight of the sulphite liquor.

If the ion content is too high when using sulphite liquor on an ammonia base, the ion content is reduced to the prescribed value by adding caustic soda or another strong base. For expulsion viscosity, preferably in the range of ammonia.

If the value is too low, for example when using calcium-, magnesium- or sodium-based sulphite liquor, the ionic content is adjusted to the prescribed value by adding a water-soluble ammonium salt of a strong mineral or organic acid such as one of the salts ammonium lignin sulphonate, ammonium chloride, monium sulfate, monoammonium phosphate, ammonium oxalate, ammonium benzene sulfonate or ammonium acetate of monochloroacetic acid; 3) water, which is preferably added by adding components 1) and 2) with the following dry matter contents: the urea formaldehyde resin 50 - 72% by weight, preferably 55 - 65% by weight, 40 - 55% by weight, preferably 48 - 52% by weight of sulphite liquor or adding an equivalent amount of water by other means.

Intimate mixture in the proportions of urea formaldehyde resin sulphite liquor 50 - 90 parts 100 - 50 parts calculated on the dry matter weights of the components by stirring whereby a heat-curable adhesive product is obtained. Desired amounts of desired additives can be included in the adhesive product mixture. Such additives may include e.g. suitable or conventional proportions of waxes, oils, fungicides, flame retardants, surfactants and paints, in which case the lignin sulphonate salts serve as dispersants for the waxes and oils.

The finished adhesive product is stable for a reasonable period of time and can be stored and used in a conventional manner.

If it is to be used in connection with the manufacture of turntables, it is sprayed on wood chips, cutter chips, fibers, planer shavings and other types of wood particles, and the resulting particles coated with glue are dried tangled in a mat of desired dimensions, using » turns an additive of glue in the order of 5 to 10% by weight of wood on an oven-dried basis. The mats can be pressed in conventional presses to the desired density under desired pressure conditions, e.g. 250 1111 sno pounds per kvaararfum what 14n ° ti11 16o ° c below 2.5: iii 10 minutes depending on disc thickness.

As can be seen from the following examples, the resulting particle board products have properties which are commercially acceptable and fully competitive with the properties of particle board products made with conventional urea resin adhesives. However, the adhesive products of the invention have the significant economic advantage that they contain a large proportion of cheap sulphite waste disposal, which results in significant cost savings at the factory where they were used.

Corresponding savings can also be obtained with other glued wood products such as plywood and fibreboard.

Examples The method of preparation and the adhesive products according to the invention are clarified in the following examples, in which the resin-based adhesive products according to the invention are identified as "Edler" and the following abbreviations are used: SSL sulphite waste MOR fracture bonding MOE elastic modulus IB internal bonding The chipboard products constituted a constituent, was tested according to ASTM test methods with the designation ASTM D1037-72.

Example 1 This example illustrates the factory use of the adhesive products according to the invention in the manufacture of chipboards of industrial quality and with a thickness of 10, 13 and 19 mm.

Four urea resins were obtained for use in this and the following examples. They have the properties listed in Table I.

Table I RESIN A, RESIN B RESIN C RESIN D '(Control) (Control Wítetal (methylol function) 1.58 1.67 1.02 1.02 Molar fraction ratio (moles e formaldehyde / moles urea) 1.60 1.50 1, 1.15 Dry matter (weight percent) 57 58 65 65.5 Viscosity at zs ° c (eps) 10 _ vu _soo 140 pa in 7.4 7.4 ----- 1.4 Diluity unlimited unlimited unlimited unlimited Resins A and B were used for the composition of the "Edler No. 1" and "Edler No. 2" adhesives described herein, respectively. The resins C and D were used as control resins.

The sulfite liquor used in the composition of the Edler adhesive in this example was derived from a concentrated commercial ammoniacalized acid sulfite liquor (free from SO 2) which contained an excess of ammonium ions to achieve the object of the invention. The content of ammonium ions was adjusted to be within the limits stated by the invention by allowing said ions to react with a measured quantity of sodium hydroxide (caustic soda). After the adjustment, the sulphite liquor contained 1.0% by weight of ammonium ions (expressed as ammonia) on a dry matter basis.

Other characteristics were as follows: viscosity at zs ° c (eps) 15 000 pH _ 7.35 Dry matter content 52.0 (weight percent) Under factory conditions, Edler-type chipboard adhesives were made by mixing urea resin and sulphite liquor at ambient temperature, the latter being used in a sufficiently large quantity that a 33% by weight dry matter content of the constituents of the solution would be obtained in the finished adhesive products. These adhesives are here called “Edler No. 1 "and Edler No. 2".

Stirring was continued until the components were thoroughly mixed and a mass of uniform appearance was obtained. During the mixing, no increase in temperature was observed and no hint of condensation of the constituent materials.

The glues prepared in the previous manner were sprayed on wood chips to make mixtures for the core material and surface material of the chipboard. These were then felted in the dry state to a mat, which was hot-pressed to form a densified chipboard product. The conditions during molding and pressing were as follows: Batch: _ Mixtures for core and surface, about 67% pine and 33% spruce Object: Bahre-Bison air-layered board, 13 mm thick Vaxine content 1% 'Adhesive content: Surface 8.3%; core 8.3% Carpet moisture content: Surface 10%, core 8% Pre-press time: 30 seconds Press time 2 minutes 52 seconds Stop time 45 seconds Decompression phase: 30 seconds (in addition to the press time) Press temperature: l60 ° C 7808082-7 H A number of boards were manufactured, whereby both types of glue were used, and the resin C served as a control. The disks were subjected to the previously mentioned ASTM tests DJO37-72 for measuring their properties with results, which are shown in Table II Table II Internal binding kPa LDB Limbe- Resin- | Percent 'Densitgtl lll kPa drawing type SSL g / cm kPa Control * 3 samples Resin C 0 0.75 17354 2620x10 average Edler no. 1 3 samples Resin A 33 0.77 16858 2703x10 average,% Water 'Swelling in absorpt. thickness mm 993 23.0 0.84 _ 18.9 972 0.79 I The previous procedure was repeated in the manufacture of particle boards with respective thicknesses of 10 and 19 mm.

The urea resin, denoted by C in Table I, was again used as a control.

Edler No. 2 glues were prepared by mixing sulphite liquor with B-resin (Table I) in an amount sufficient for the solids of the solution to correspond to 33% by weight of the dry matter content of the gluing product. Like the sulphite liquor used in the manufacture of the 13 mm particle board described above, the sulphite liquor used in the manufacture of the 10 and 19 mm thick particle board, which are relevant in this context, consisted of a commercial concentrate. ammonia-calibrated acid sulphite liquor free from SO2 and initially containing an excess of ammonium ions, but which was adjusted by reaction with sodium hydroxide in a pre-calculated amount so that the final ammonium ion value would amount to 0.4% by weight (expressed as ammonia) of the entire corresponding dry matter content of the sulphite liquor.

Other characteristics of the sulphite liquor were as follows: Viscosity at 25 ° (cps) l 200 pn's, 9s Dry matter (weight percent) 50.2 Both the resin adhesives which constituted the control and the resin adhesives according to the invention were sprayed on wood particles, which then in dry state was formed into a mat, which was hot-pressed under the following conditions of molding and pressing: * S vaososz-7 Batch: Mixtures for core and surface, about 67% pine and 33 2 spruce Object: Bahre-Bison air-layered board, thicknesses, named Wax content: I% Adhesive content Surface 8 l, core 8 2 Carpet moisture content: Edler 10%; control 9.6% Pre-press time: 30 seconds pfß fi stídï 19 mm, 45 minutes; 10 mm, 2! minutes Stop time: 19 mm, 65 seconds; 10 mm, 35 seconds Decompression phase: 19 mm, 40 seconds; 10 mm, 20 seconds (in addition to the pressing time) Press temperature 19 mm, 16o ° c; 10 mm, 1s4 ° C Several test specimens of the resulting chipboards were subjected to the conventional ASTM tests with average test results as follows: Table III Adhesive Resin Percent Density MOR MOE Inner binder% Water Sheet thickness_ drawing type SSL g / cm3 kPa kPa ning kPa absorpt. Swelling in - thickness mm Control '- sample co 0.76 19237 2s7sx1o3 since 29.7 in / o, s4 average Edler no. 2 sample B 33 0.79 18543 3034xl03' 800 24.6 10 / 0.79 average Control - 3 test 'C 0 0.76 20133 3l99xl0 972 22.9 _ 19 / 0.91 average »E fl ler no. 2 3 test B 33 0.75 17031 3082xl0 average 738 18.9 19 / 0.76 From the above it is clear, that the adhesive products according to the invention, which contain up to 1/3 of their weight, sulphite liquor, can be used in the manufacture of chipboards with commercially acceptable properties, which are advantageous in comparison with the properties of control boards made with pure urea resin adhesives. This indicates that the rheological and curing properties of the adhesives according to the invention are fully compatible with the normal manufacturing processes in chipboard production and can be used without having to make any changes to the manufacturing process or without reducing the factory capacity. vsososz-7 i ,,, The sulphite glue adhesives according to the invention are advantageous in these respects compared with the results obtained with pure urchart glues which, on the basis of many years of production experience, have been carefully adapted to the special requirements of chipboard technology and other wood gluing techniques. In fact, it has been found that particle board made with the adhesive according to the invention had considerably better water resistance properties than particle board made with commercial adhesives of the same class. In contrast to the adhesives according to the invention, other adhesive compositions based on sulphite liquor in the tests taken have not been shown to be able to reach the same level. These tests not only gave chipboard with poorer physical properties, but due to unfavorable rheological “properties of the adhesive caused interruptions in the manufacture, e when it proved impossible to produce a carpet, which could be shaped and handled on a satisfactory way. Example 2 'This example further details the preparation of adhesive products according to the invention containing from 10 to 50 {sulphite liquor and the properties of such products.

In connection with a laboratory scale study, a series of adhesive products of urea formaldehyde darts and sulphite liquor was prepared using the procedure set forth in Example 1. The glue contained 10, 30 and 50 weight percent sulphite liquor, respectively, calculated on the basis of this dry substance. The glue was applied to wood chips, which were then loaded onto carpets and hot-pressed into chipboard, the properties of which were tested. The properties of the experimentally produced chipboards were then compared with control chipboards manufactured in a similar manner, but which did not contain any sulphite liquor.

DB k0mm6rSíel18 urea resin adhesives for particle board used for inspection purposes showed the properties given in Table I in Example 1 under the headings "HARTS C" and "HARTS D", respectively.

The urea resin component of the sample adhesive in this example had the properties listed in the columns designated "HARTS A" and "HARTS B" in Table 11, I Example 1. The sulfite liquor component of the sample adhesive consisted of a substantially sulfur dioxide free concentrated sodium alkalized sulfite liquor, to which sufficient ammonium sulphate has been added to produce a sulphite liquor product containing 0.425% by weight of ammonium ions, expressed as ammonia by the weight of the dry matter of the sulphite liquor. '. .., .. ,, _, _ 17 7808082-7 * Other properties of the sulphite liquor were as follows: Viscosity cps (at ZSOC) 830 Dry matter content (weight percent) 50 pH 6.8 The conditions of molding and pressing in the manufacture of the chipboards where as follows: Kit: Forming: Glue content Douglas fir wood Air felted carpet 7 S total dry matter Carpet moisture- 9.5 1 content Press time: 4 minutes, 45 minutes, 5 minutes; 41 minutes on average Pressure temperature: 163 ° C Sheet thickness: 19 mm Sheet specific gravity: 0.73 3 0.15 During testing, the chipboard products showed the following properties: Control adhesive ___ §d1er adhesive _ * _ Sulfite liquor, dry matter 0% 10% 30% S0% Resin Component Resin A MOR 20837 21237 21719 l9996 IB 779 758 690 462 Resin D MOR 21650 22202 21099 16755 IB 779 814 772 379 It should be noted that the Noble Compositions containing up to 50% sulphite liquor on dry matter base had commercially acceptable properties for some purposes. It also appears that resins with Wittetal in the range 1.0 to 1.8 give good Edler adhesives.

Example 3 This example indicates the effect which is manifested in the properties of the chipboards, when more than the stipulated amount of ammonium ions is included in the adhesive products according to the invention, i.e. more than 4% by weight of ammonium ions (expressed as NH3) dry matter basis on the dry matter basis of sulphite liquors.

Urea resin, commercial grade sulphite liquor with a high carbon content of ammonium ions and 18% by weight of wax was thoroughly stirred and mixed at ambient temperature, using sufficient sulphite liquor to produce 33% of the dry matter of the sulphyl liquor in the resulting the adhesive product calculated on the dry matter weight. The ammoniacalized sulfite glutone contained 5.7% by weight of ammonium ions (expressed as ammonia) of the dry matter base of the sulfite liquor. The other properties of the solution and the properties of the test resin, designated "Resin E" as well as the corresponding data concerning a commercial urea resin used as a control and designated "Resin F" are given in Table IV below.

Table IV Property Resin Resin Resin F Sulphite waste finish EW (control) Molar fraction ratio 1: 1.8 '1: 1, 3 --- Dry matter (weight 65 65 52 percent) 2 viscosity at 21 ° c (eps) 400 295 3 ooo pH 7 , 4 7,5 7,2 wícfeta1_ 1,72 1,02 --- Water solubility unlimited unlimited unlimited Ammonium content "'"' 5.7% (weight percent) E-resin was used in the manufacture of "Edler glue No. 3".

-F resin was used as a control.

Two batches of 10 mm chipboard were made with the above were as follows: Batch: Object: Vaccine content: Adhesive content: pH of the adhesive: Mat moisture content: Pre-press time: Press time: Stop time: Decompression phase: Press temperature: two glue products, forming and pressing conditions core and surface, about 67% pine and 33% spruce- Bahre-Bison air-layered board, thicknesses, mentioned 2 1% Surface 8.3%, core 8.3% Control 7.8; Noble 4.4 Control 8.5%; Edler 9.5% 30 seconds 2 3/4 minutes 45 seconds 40 seconds (in addition to the pressing time) 1s4 ° c '19 7808082-7 The chipboards gave during testing the values found in the table below V: ggpell v Linme- Resin- Percent Disc thickness4 Densi et Prepress ~ drawing type SSL play mm g / cmš ninglnn F ° Tts "" "" Control _ sample Resin F 0 10 0.75 0 average Edler no. 3 * 'sample Resin E 33 10 0.74 0.79 average Cont. Lhmbe- MOR lí fl š Internal binding-% Water Swelling in "" 'drawing kPa kPa ning kPa absorpt. Thickness mm Control sample 18617 27sxx1o3 602 26.8 9.11 average Edler no. 3 3 sample 9687 l855xI0 276 33.7 1.04 average Table V clearly shows the undesirable effect on the general properties of the boards, when the content of ammonium in the sulphite liquor reaches high levels. Both strength and water resistance properties are markedly reduced.The high ammonium content, fast curing, gives rise to soft surfaces on the boards and a consistent reduction in strength properties due to premature curing. length is also significantly reduced, which means a serious risk of gel formation in the factory's pipelines and equipment. Example 4 This example illustrates the use of different categories of sulfur dioxide-free sulfite liquors for the manufacture of the adhesive products described herein. The sulfite liquors tested were: A concentrated sodium alkalized acid sulfite liquor, to which sufficient ammonium sulfate had been added to provide an ion content (expressed as NH 3) of 0.4 2 of the dry matter base of the sulfite liquor; A concentrated commercial calcium alkalized sulphite liquor which had been desugared and contained ammonium ions (expressed as NH3) in an amount of 0.34% by weight of the dry matter base of the sulphite liquor.

A concentrated ammonia-calibrated commercial sulphite liquor with a high ammonium content, which was partially reacted with caustic soda, so that the 78μ8822 ° 7 residual ammonium ion content (expressed as NH3) became 0.46% by weight of the dry matter base of the sulphite liquor.

The properties of these sulfite liquors are listed in Table VI. The pH of each was adjusted to about 7.0 before being allowed to form an ingredient in an adhesive.

Table VI Sulphite liquor Viscosity 25 ° C ßmnmniak lbrrsannstann pH (eps) weight percent weight percent 25 ° C Sodium base _ modified with 300 0.4 50.3 4.80 ammonium sulphate Calcium base, desugared 1066 0.34 51.9 3.79 Ammonium base treated with 740 0.46 48.7 7.12 caustic soda A commercially pure urea resin adhesive for Spanish discs was used as a control and was designated "Resin D" (Table I).

The urea resin adhesive used in the composition of the composition of the sample adhesive was "Resin B" and had the physical properties given in Table I of Example 1.

The adhesive products had the same formulas as in the previous examples. They were sprayed on wood particles which were then laid up in mats and hot pressed under the following_forming and pressing operations in Set: Wood particles of Douglas green Forming: Dry felted Wax content 0% Adhesive content 7% Carpet moisture content: 9% Sheet thickness: 3/4 "Pressing time, 4.5 minutes Z sheets, 5 minutes Stop time: 70 seconds The chipboards produced were tested according to ASTM test method D-1037-72 with results given in Table VII, where the values are averages for samples performed with four copies of each chipboard quality. 31 7808082-7 Iahff1___l_, .V ll Line drawing lálmnet} araktorisE¿ @} _ of liart type LKMR Internal binding Edler no. 4 Sodium base modified B 19133 655 with ammonium sulphate _Edler no. 5 Calcium base, desaccharated B 18892 627 Edler treated with B Ammon no. soda Control None D 20306 772 The strength values for the tested washers are thus largely equal to those from the control boards and are well within commercial acceptance feasible limits.

- Example 5 This example illustrates the use of a magnesium alkalized acid sulphite liquor in the composition of adhesive products according to the invention.

The urea resin used in the composition of the adhesive product was identified as "Resin B" in Table I above. It had a dry matter content of 58% by weight, a Wittetal of 1.67 and a molar ratio of 1.50.

The sulfite liquor used was a commercial magnesium alkali metal sulfite liquor containing 47% dry matter.

The control material consisted of a ureahnrts of commercial quality with a molar fraction ratio of 1.25 and did not contain any sulphite liquor (Resin G). The core and surface adhesive products (Edler Nos. 7 and 7a) having a ratio of 67/33 (resin to sulphite liquor) were prepared by stirring urea resin and sulphite liquor together with ammonium sulphate as the source of the ammonium ions, in the following proportions: The core layer of the disk : 320.7 g Resin B, 58.5 g dry matter, pH 7.0 198.6 g magnesium alkalized acid sulphite liquor 47% dry matter, pH 4.5 8.5 g ammonium sulphate Surface layer: 329.3 g Resin B - 58, 5 l dry matter, pH 7.0 203.9 g magnesium alkalised acid sulphite liquor 47% dry matter, pH 4.5 3.0 g ammonium sulphate The resin adhesive was sprayed on wood particles, using an application of 11.5% for the surface layer and 7% for the core based on torr ~ Tv IJ 7808082-7 substance. The glue-coated wood particles were then felted into mats and pressed into 17.5 mm sheets in a conventional manner, using a press with a pressure of 3500 kPa, the time interval for closing was 30-40 seconds, the pressing phase was 3.5 minutes, and the pressing temperature 177 ° C. The properties of the resulting disks were tested (ASTM D1037-72] with results, which are reproduced below, which are average values for five disks, which allowed a recovery time for voltage equalizations of 48 hours in the prevailing atmospheric conditions, before they were tested.

Table VIII Glue designation Hard type Density MOTHER Swelling Water g / cm3 kPa kPa in thickness absorption nnder 2 hours. under 2 1; p _ __ "% 1 Control 'Resin G 0.68 15397 600 16.1 91.6 Ureaformaldehyde Nhgnesiualkalized Resin B 0.73 18299 640 17.6 77.2 sulfite liquor (Edler Nos. 7 and 7a) Example 6 This example illustrates the use of magnesium alkalized sulphite liquors in the adhesive products according to the invention, but under somewhat different conditions, especially with regard to the use of a sulphite liquor with a lower pH than those used in Example 5.

Particleboard was prepared, the control resin being the same as resin G) used in Example 5, and the test adhesive for core and surface layer (Edler Nos. 8 and 8a) was also similar, but contained 50% instead of 47% of sulphite liquor dry matter in the ratio 67/33, urcaformaldehyde resin to sulphite liquor on a dry matter basis. The compositions used for the core and surface adhesives of the particle board were as follows: Core layer: 320.7 g Resin B (Table 1) urea formaldehyde resin 58% dry matter, pH 7.0 186.7 g magnesium alkalized acid sulphite liquor, SO% dry matter , pH 3.2 2.5 g ammonium sulphate Surface layer: 329.3 g Resin B, urea formaldehyde resin, 58% dry matter, pH 7 191.7 g magnesium alkalised acid sulphite liquor 50 t dry matter, pH 3.2 ~ 2.8 g ammonium sulphate 7808082- In the production of the chipboards, the total amount of glue, the same manufacturing method, the same control resin and the same board thickness as indicated in Example 5 were used. The pressing phase was 3 minutes and 12 seconds at 177 ° C. The test results (average for five discs) were as follows: Table was Glue designation Hart type Density MOR IB Swelling Water- 3 / Cm3 kPa kPa in thickness absorption for 2 hours. under 2 hours. % l Control Resin G 0.68 15396 600 16.1% 91.6 in Urea formaldehyde as described above, glue products are made from urea resin sulphite liquor, and chipboard and other glued wood products are made by means of this, whereby the source of ammonium ions instead of ammonium sulphate may be: ammonium chloride, mono-ammonium phosphate, ammonium oxalate, ammonium benzene sulfonate and ammonium acetate of monochloroacetic acid.

Example 7 This example illustrates the effect of including a low molecular weight and low Wittet urea resin composition in the adhesive products of the invention.

An adhesive product consisting of urea sulfite liquor was made using the procedure described in Example 1. The urea resin component of the adhesive tested had the following properties: Wittetal 0.76 Molecular ratio 0.90 (moles formaldehyde (moles urea) Dry matter (wt%) 65 Viscosity at 2S ° C (cps) 70 pH 7.3 Dilutability unlimited The sulphite liquor component of the tested adhesive product had the properties of the sulphite liquor described in Example 2.

The molding and pressing conditions used in the manufacture of the board product were as described in Example 2. 7808082-7 f * When tested, the Spanish disc products showed the following properties: - MOR 9522 IB 152 This example clearly shows the undesired effect when using a urea formaldehyde resin with a low molar ratio and low Wittetal. Both the breaking strength (MOR) and the internal binder volume (IB) are clearly below the minimum values in the National Particle Board Association's standards for chipboard products (MOR 11032, IB-414).

Claims (6)

25 7808082-7 llglt-: QIFKRAV Process for the preparation of an adhesive with the components ureaphonaldehyde resin, sulphite liquor and water, characterized in that 1) The urea formaldehyde resin is selected with the following properties: molar ratio formaldehyde / urea 1.0 - 1.8 pH 6 - 8 viscosity preferably in the range of 50 to 250 centipoises (measured at 6595 dry matter content and 25 ° C) while determining by controlling the Wittetzll of the resin that the methylol content of the supplied resin is within such limits that a Witt number of 1.0 - 1.8 is contained; 2) The salt liquor is selected with the following properties: pH 3 - 9 preferably in 3.5 - 4,5 viscosity preferably in the range 500 - 4000 centipoises (measured at 50% dry matter content, and 25 ° C) and with the content of the liquor of ammonium ions 0.2 - 4.0% by weight (expressed as NH3) calculated on the dry matter weight of the sulphite liquor. 3) The water is preferably supplied by adding components a1) and 2) with the following dry matter contents: the ureaphonaldehyde resin I 50 - 72 wtf preferably 55-65 wt.%, The sul luttlutene 40 - 55 wt.%, Preferably 48 - 52 wt.%, 7803082- 7, 26 or by adding an equivalent amount of water in another way, the components being mixed in the proportions of urea formaldehyde resin 50-90 parts of sulphite / 10-50 parts - calculated on the dry matter weights of the components by stirring, whereby a heat-curable adhesive product is obtained. 2. A process according to claim 1, characterized in that the liquor is checked for its content of ammonium ions, which must be 0.2 to 4.0 weight percent (expressed as Nl-Is) calculated on the dry matter weight of the sulphite liquor . If the ionic content is too high when using sulphite liquor on an ammonium base, the ionic content is lowered to the prescribed value by adding baking soda or another strong base to drive away ammonia. If the value is too low, for example when using calcium, magnesium or sodium-based sulphite liquor, the ion content is adjusted to the prescribed value by adding a water-soluble ammonium salt of a strong mineral or organic acid such as one of the salts ammonium lignin sulphonate, ammonium chloride, ammonium sulphate. monoammonium phosphate, ammonium oxalate, ammonium benzenesulfonate or ammonium acetate of monochloroacetic acid. 3.,; Process according to Claim 1 or -Z, characterized in that at least one sulphite liquor of the calcium-based, magnesium-based, sodium-based or ammonium-based type is used as the sulphite liquor. 4. A process according to claim 3, characterized in that the sulphlutene comprises an acidic calcium-based sulphite liquor, a sufficient amount of a water-soluble ammonium salt of a strong acid being added to ensure said content of ammonium ions. A process according to claim 3, characterized in that the sulphite liquor comprises an acidic magnesium-based sulphite liquor, wherein a sufficient amount of a water-soluble ammonium sulfate of a strong acid is added to ensure said content of aminonium ions. , 6. A process according to claim 3, characterized in that the sulphite liquor comprises an acidic sodium-based sulphite liquor, wherein a sufficient amount of a water-soluble ammonium salt of a strong acid is added to ensure said content of ammonium ions. "7808082-7 Summary Present The present invention relates to a process for the production of an adhesive product suitable for the manufacture of particle board and other wood products, which adhesive product comprises a large proportion of sulphite liquor from sulphite treatment of wood pulp, which can be readily used in the manufacture of particleboard using conventional equipment and methods and which results in the production of glued wood products with commercially acceptable properties, which correspond to the marketing standards for such products. According to the invention, the adhesive product produced consists of 50 to 90 parts by weight of urea resin in solid form and from 10 to 50 parts by weight of sulphite waste liquor based on the dry matter value of the sulphite liquor. The adhesive product also contains as a key component of from 0.2 to 4.0% by weight of ammonium ions (expressed as NH3) calculated on the dry matter base of the sulphite liquor.