WO2004018581A2

WO2004018581A2 - Resin curing agents, compositions and products containing same

Info

Publication number: WO2004018581A2
Application number: PCT/US2003/025959
Authority: WO
Inventors: Alan M. Yeoman; Tien-Feng Ling; Giulio Pieter Formenti; Bruno C. Ortiz Ugarte
Original assignee: Biolab, Inc.
Priority date: 2002-08-20
Filing date: 2003-08-19
Publication date: 2004-03-04
Also published as: WO2004018581A3; AU2003258292A8; AU2003258292A1

Abstract

A process for making an article from an amino resin comprising mixing an amino resin with a halogenated catalyst in a sufficient amount to form a reaction mass, shaping the reaction mass and heating said reaction mass to produce a cured amino resin article.

Description

RESIN CURING AGENTS, COMPOSITIONS AND PRODUCTS CONTAINING SAME

Cross Reference To Related Application

[0001] This application claims the benefit of our copending provisional application No. 60/404,981 filed August 20, 2002, which is relied on and incorporated herein by reference.

Background

[0002] The present invention relates to certain oxidizing halogen products applied in various product forms either alone or in combination with other catalysts for the curing of resins, particularly amino resins, products and compositions produced therefrom.

[0003] More particularly, the present invention relates to a method for making a wood composite article employing synthetic organic resins and certain oxidizing halogen catalysts.

[0004] Still further, the present invention relates to a catalyst system that enables a reduction in curing times for certain synthetic organic resins. [0005] Amino resins, also called aminoplasts, are thermosetting polymers produced using an aldehyde and a compound containing the amino group (NH₂). Formaldehyde is the most common aldehyde with urea and melamine being the most important amino compounds. Urea Formaldehyde (UF), melamine- formaldehyde (MF) and melamine-urea-formaldehyde (MUF) are common examples of amino resins. Amino resins are tailored to satisfy a wide range of performance requirements through formulation with additives, physical processing control and various methods for their application and use. Amino resins are used in many applications such as binders, adhesives, impregnating agents, laminating agents, molding compounds and coatings. [0006] In a more detailed aspect, the present invention relates to the use of amino resins as adhesives for wood based composites. The advantages of the new catalyst system of the present invention will be realized in other applications of amino resins.

[0007] Amino resins are used extensively as adhesives, especially for cellulose based composite materials. For example medium density fiberboard (MDF) and particleboard (PB) often use UF, MF or MUF resins to bond the substrate (fibers or particles) to create a composite product. The resin is prepared to meet requirements such as internal bond strength, moisture tolerance and curing time for the composite material being produced. These are matters well understood in the art. Resin, in liquid form, is typically blended with the substrate before the mixture is hot pressed into the desired form. Amino resin adhesives are also used in several laminating and coating applications.

[0008] Thus, amino resins and especially urea formaldehyde resins are employed in many fields; i.e., particle board manufacture, medium density fiberboard and hardwood plywood manufacture, fabrication of glass fiber roofing mats, in molding compounds, for paper treating/coating applications, for surface coatings and textile treatments.

[0009] Because amino resins are thermosetting polymers, exposure to elevated temperature for sufficient time will solidify, or cure, the resin. For UF resins the curing reaction is due in part to increased polymer chain length, via an addition reaction. But the more important curing reaction is thought to be crosslinking, or a condensation reaction. See Urea Formaldehyde Resins, by Beat Meyer, Addison- Wesley Publishing Company, London (1979). Condensation is a dehydration reaction between amide and methylol groups resulting in methylene bridges between amide nitrogen atoms. Hardeners, or catalysts, are often used so that lower press temperatures and/or shorter press times can be used. An obvious advantage to reducing press time is improved productivity. Lower press temperatures, shorter press times or a combination of reduced temperature or time in the hot press step also reduce decomposition or volatilization of components in the resin or the substrate in addition to reducing internal steam pressure. [0010] Exposing UF resins to high temperature can hydrolyze the resin to urea and formaldehyde reducing polymer chain length and crosslinking thereby resulting in lower bond strength and higher formaldehyde emission. Increased formaldehyde emissions from the press due to high press temperatures and times increase worker exposure and pollution control costs, see Forest Products Journal, vol. 52, No. 52, "Volatile Organic Compound Emissions During Hot-Pressing of Southern Pine Particleboard: Panel Size Effects and Trade-Off Between Press Time and Temperature", by W. Wang, D. Gardner and M. Baumann. Thermal decomposition of cellulose substrates can lower fiber strength thereby weakening the composite. Volatilization of components present in the substrate, or volatilization of substrate thermal decomposition products, can increase worker exposure and pollution control costs.

[0011] Wood is a poor heat conductor. For this reason heat transfer via steam generated from moisture present in the substrate is a key means to cure the adhesive in the core of the composite article. However steam also increases internal pressure. Some programs include a pressure relief step where the hot press pressure is reduced or is opened slightly to partially vent this internal pressure and then closed again before curing is complete. When the composite article is removed from the press the internal bond strength must be greater than the internal pressure or the desired thickness will not be maintained. If the internal bond strength of the resin with the cellulous material is insufficient, the product will tend to "spring back" or return at least partially to the dimensions prior to being subjected to pressing action. It is desirable to reduce press temperatures and press times to reduce internal pressure and increase productivity. [0012] UF resins with higher free formaldehyde levels cure more rapidly than resins with lower free formaldehyde levels, presumably because the crosslinking reaction proceeds more rapidly. However the level of free formaldehyde continues to be reduced to comply with ever more stringent formaldehyde emission standards and regulations for composite products.

[0013] The UF condensation reaction, responsible for resin curing, is acid catalyzed. In some applications the pH is lowered sufficiently by acidic extractives from the substrate. In many cases, however, curing agents are used which accelerate the condensation reaction by lowering the pH in the pressing operation. Care must be taken because if the pH is reduced too much acid hydrolysis of the resin can cause poor bonding performance. According to Meyer the optimum range for UF resin curing is between pH 2 and pH 4.

[0014] Many components have been identified as curing agents (also known as catalysts or hardeners). Meyer lists many used in UF resin applications. Curing agents are either weak acids that lower the pH directly or react with the resin components to lower the pH. The most common class of hardeners for UF resins is ammonium salts. The reaction of the ammonium ion with formaldehyde forms acid and hexamethylene tetramine (also known as hexamine) as shown below for ammonium sulfate.

Equation 1 2(NH₄)₂SO₄ + 6CH₂0 → N₄(CH₂)₆ + 6H₂O + 2H₂S0₄ [0015] Particleboard manufacturing is a well known operation and usually includes a variety of the following steps: solid wood is hogged, fiberized or flaked and then dried to an approximate moisture content of 3-6% by weight. It is then screened and stored in bins or silos. The resulting chips are sized in a blender by spraying with wax or petrolatum. Aqueous resin, typically containing about 65% solid, such as urea formaldehyde is then sprayed to yield an approximate resin solid content of 6 to 10% by weight on the basis of the dry wood weight on the chips. Occasionally the sizing and the impregnation with the aqueous resin can be combined in a single step.

[0016] Due to the manner in which this process is carried out, the resin concentration in the face layer is different from that in the core. The face layer of a wood composite is the surface exposed to view in the finished state. The process is controlled carefully to provide a reliably uniform resin coverage of the wood chips that make up the product. Accurate spray control using meters to minimize the use of glue can be used to reduce the price of the finished product. A mat is formed on the metal cauls which move stepwise from the bottom face to the core to the top face material bin. Mats can be prepared either continuously or in batches. Mat pressing can also be done as either a continuous operation or on individual mats. The surfaces in contact with the mats can be heated to 200°C (392°F) or higher for intervals of up to 12 minutes. The pressure is adjusted to compress the mat at the desired rate and to the desired thickness. Press closure and opening procedures are often elaborate cycles during which pressure might be temporarily or slowly lowered to vent steam. The hot boards are then air cooled because urea formaldehyde resin bonded particleboard is weakened and discolored if the heat is retained too long. Boards can then be trimmed and cut. Sanding of the boards on both sides may be performed which typically brings the thickness tolerances up to plus or minus 0.055" (1 mm). Other variations of the basic method are known in the art and can be contemplated while carrying out the process using the materials described herein.

[0017] It has been observed that increasing ammonium salt levels increases cure rate. However a point is reached where increasing ammonium salt levels does not increase cure rate presumably because the free formaldehyde has been converted to hexamine. Summary of the Invention

[0018] In an embodiment of the present invention there is provided a catalyst system based on selected halogenated oxidizing agents; more particularly halogen donor compounds that are derivatives of isocyanurate compounds and hydantoin compounds, such as l-bromo-3-chloro-5, 5-dimethyl hydantoin (BCDMH). Particularly advantageous for purposes of the present invention is the combination of BCDMH and an ammonium salt, such as ammonium sulfate, (NH_ ₂ S0₄. [0019] The catalyst system of the invention can be used as powders, water dispersions, solutions in organic solvents and encapsulated for latent performance. Of particular interest is the use of the catalyst curing system of this invention with aminoplast resins such as urea formaldehyde, melamine formaldehyde and the like for the formation of wood composite products.

[0020] A large use for such catalyzed resin systems is in the field of particle board as well as fiberboard, plywood, fiberglass mats and wood composite products in general.

[0021] In another embodiment of the invention, there is provided comminuted wood composite products made with the aforementioned catalyst systems. [0022] According to another embodiment of the invention, a process is carried out for making a wood composite article by impregnating comminuted wood with a synthetic organic resin and curing the resulting mass with selected halogenated oxidizing agents.

[0023] Yet another embodiment of the invention concerns the resin curing catalyst system which enables decreasing the curing time particularly for products made from urea-formaldehyde resin coated comminuted wood. [0024] Typical oxidizing agents suitable for the present invention include:

1. Halogenated hydantoins - l,3-dichloro-5,5-dimethylhydantoin (DCDMH), l,3-dibromo-5,5-dimethylhydantoin (DBDMH), l-bromo-3-chloro- 5,5-dimethylhydantoin (BCDMH), and l-bromo-3-chloro-5-mefhyl-5- ethylhydantoin (BCMEH).

2. Chlorinated cyanuric acids - sodium dichloroisocyanurate, sodium dichloroisocyanurate dihydrate, potassium dichloroisocyanurate, dichloroisocyanuric acid (DCCYA), trichloroisocyanuric acid (also known as trichloro-s-triazinetrione, TCCA), and the mixed complex of 4 potassium dichloroisocyanurate to 1 trichloroisocyanuric acid.

3. Haloglycolurils - chloro-substituted glycoluril and bromo- substituted glycoluril.

4. Inorganic chlorine source - Cl₂, lithium hypochlorite (LiOCl), calcium hypochlorite ((Ca(OCl)₂), sodium hypochlorite (NaOCl), hypochlorous acid (HOC1), and chlorine dioxide (C10₂).

5. Inorganic bromine source - Br₂, hypobromous acid (HOBr), sodium hypobromite (NaOBr), BrCl, a bromide activated by Cl₂, NaOCl, or 0₃. Note: examples of water soluble metal bromide salts include sodium bromide, potassium bromide, magnesium bromide, calcium bromide, and zinc bromide. Water soluble ammonium bromide salts include tetraethylammonium bromide, tetramethylammonium bromide, and ammonium bromide.

6. Haloamines - NHC1₂ NH₂C1, and halogenated hydantoins.

7. Halosulfamates - N-bromo or N-chloro sulfamates .

Detailed Description of Invention

[0025] The present invention will now be described in further detail in connection with a number of examples carried out whereby the desired results obtainable by the present invention will become apparent. [0026] The resins tested all had nominal solids content of 65% on a weight basis. However, this is merely for purposes of illustrating the desirable features of this invention. The appropriate solids content will vary depending on the particular use as will be apparent. For example, solids content can vary from 10% to nearly 100%. Treatment levels are expressed in terms of weight % of the treatment (on an active ingredient basis) in the resin (as received). Laboratory Resin Cure Tests:

[0027] A laboratory cure time test (also known as a gel time test) was used to evaluate the effectiveness of curing agents. The tests were conducted by adding curing agent to resin in a culture tube (20 mm x 150 mm). The amounts of resin and curing agent (total weight approximately 10 grams) were adjusted to give the desired concentration of curing agent expressed as weight % curing agent (as active ingredient) in the resin (as received). The resin and curing agent mixture in the culture tube was then immersed in a 95 °C (203 °F) circulating water bath where it was manually stirred with glass rod until the mixture solidified, immobilizing the glass rod, indicating curing. The cure time was measured from the time the culture tube was immersed in the water bath.

[0028] Generally, the amount of catalyst ranges from 0.1% to 5% based on the total weight of resin plus catalyst.

[0029] Three urea formaldehyde resins were tested: GP487D45 and GP487039 (available from Georgia Pacific Corporation) and BASF K-350 (available from BASF Corporation). A melamine formaldehyde (MF) coating resin was also tested, GP542D59 (available from Georgia Pacific Corporation). [0030] The following were tested as curing agents: ammonium sulfate, sodium hypochlorite (5.25% solution), sodium bromide reacted with sodium hypochlorite, l,3-dichloro-5,5-dimethyl hydantoin (DCDMH), dimethyl hydantoin (DMH), sodium dichloroisocyanuric acid (DCCYA), isocyanuric acid (CYA), trichloro isocyanuric acid (TCCA), l,3-dibromo-5,5-dimethyl hydantoin (DBDMH), 1- bromo-3-chloro-5,5-dimethyl hydantoin (BCDMH), hydrogen peroxide, aluminum sulfate, and various physical forms of BCDMH, and mixtures thereof. Particularly good results are obtained when the halogenated oxidizing agent is combined with an ammonium salt of a mineral acid; e.g., chloride, nitrate and sulfate salts of ammonia.

Differential Scanning Calorimetry (DSC) Tests:

[0031] DSC was used to quantify thermal events of test materials as a function of temperature. During these tests the temperature of the calorimeter was increased from 25°C to 200°C (77°F to 392°F) at a rate of 10°C (18°F) per minute. These tests were performed at the Wilhelm-Klauditz-Institut fuer Holzforschung, a division of the Fraunhofer Institute, in Braunschweig, Germany. The two UF resins tests were GP487D39 (available from Georgia Pacific Corporation, very similar to GP487D45 described above) and BASF K-350 (available from BASF Corporation). The effects of ammonium sulfate, BCDMH and a synergistic blend of these curing agents were measured. Resin Hardening Studies:

[0032] The viscosity of resin treated with curing agent was measured as a function of time at the Wilhelm-Klauditz-Institut fuer Holzforschung, a division of the Fraunhofer Institute, in Braunschweig, Germany. The temperature of a plate- plate viscometer (glue line thickness of 0.250 mm [0.0098 in], 1 Hz oscillation) was increased from 25°C to 90°C (77°F to 194°F) at a rate of 0.5°C (0.9°F) per second. The viscometer temperature is held at 90° C (194°F) until the resin has hardened. The viscosity of the resin is typically under 0.50 Pa-S (500 centipoise) initially with hardening indicated by viscosity values over 10³⁵ Pa-S (10³⁸ centipoise).

Particleboard Panel Tests:

[0033] The test particleboard panels with a nominal density of 650 kg/m³ (40.6 #/ft³) were prepared using a pilot press at the Wilhelm-Klauditz-Institut fuer Holzforschung, a division of the Fraunhofer Institute, in Braunschweig, Germany. The panels were made using virgin Spruce wood chips for both the core layer and the surface layers. The core (larger chips) comprised approximately 60% by weight of the board. The surface chips were smaller than the core chips. The core resin used was GP487D39 (available from Georgia Pacific Corporation, very similar to GP487D45 described above). The surface resin used was GP729D71 (available from Georgia Pacific Corporation). The core chips were blended with approximately 12.3% core UF resin (weight resin as received/wood weight [8% resin solids/wood weight]) and the surface chips were blended with approximately 15.4% surface UF resin (weight resin as received/wood weight [10% resin solids/wood weight]). The desired level of curing agent was mixed into the resins prior to blending the resin with the chips. In all tests the only treatment added to the surface resin was 0.5 weight % ammonium sulfate in the resin (as received). The treatment of the core resin varied based on the objective of the tests. In addition, some tests used core resin levels lower than the nominal 12.3%. [0034] The resin coated particles were hand formed into a 3 layer mat having a surface layer above and below the core layer. The mat was then placed in the pilot press to produce the panels. The press, with a surface temperature of 200°C (392°F), was programmed to close to the nominal thickness of 16 mm (0.63 inches) and hold for the desired time before opening. The panel was removed from the press and allowed to cool. The thickness of the panel was measured immediately after cooling to determine springback from nominal thickness. Samples from the panel were then tested, after conditioning, for internal bond strength. [0035] The halogen donors of the present invention may be any source of oxidizing halogen. Such oxidizing halogens are in the +1 oxidation state and when hydrolyzed will exist as the hypohalous acid or hypohalite anion. Such halogen compounds include, but are not limited to, the halohydantoins, haloisocyanuric acids, haloamines, and halosulfamates, as well as alkali metal or alkaline earth hypochlorites and element chlorine or bromine, such as Cl₂ or Br₂. Other halogen donors include hypobromous acid and hypobromite such as is generated by the addition of BrCl, or from the reaction of a bromide with Cl₂, NaOCl or 0₃. [0036] In one preferred embodiment the halogen donor is characterized by having the halogen bonded to a nitrogen moiety.

[0037] In another preferred embodiment the halogen donor is a halohydantoin such as mono or dihalodialkylhydantoin and derivatives thereof. Preferred examples include bromochlorodimethylhydantoin, dibromodimethylhydantoin, dichlorodimethylhydantoin, monobromo-dimethylhydantoin, monochlorodimethylhydantoin, bromochloro-methylethylhydantoin, dibromomethylethylhydantoin, dichloromethyl-ethylhydantoin, monobromomethylethylhydantoin and monochloro-methylethylhydantoin. Halohydantoin derivatives having other alkyl groups are envisioned within the present invention but are not presently commercially available. Likewise, polymers and other compounds containing one or more halohydantoin moieties are contemplated within the scope of the present invention, but are not presently economically preferred.

Examples

Example 1 :

[0038] The cure time of the Urea Formaldehyde (UF) resin (received from

Georgia Power Resins, GP487D45) with no curing agent addition was determined as described in the Laboratory Resin Cure Test section above to be 2,688 seconds

(44 minutes 48 seconds). This cure time is too long to be used commercially which is consistent with industry practice of adding curing agents to decrease cure times.

Example 2:

[0039] The cure times of the UF resin described in Example 1 as a function of treatment with ammonium sulfate levels is shown in Table 1. TABLE 1

[0040] These results confirm that ammonium sulfate dramatically reduces the cure time of this type of UF resin. The results also demonstrate one of the limitations of ammonium salts as curing agents, increasing levels beyond a certain point does not decrease cure times. Example 3:

[0041] The cure times of the UF resin described in Example 1 as a function of treatment with free oxidizing chlorine level was investigated in this Example. The source of oxidizing chlorine used was 5.25% sodium hypochlorite solution. Results are shown in Table 2.

TABLE 2

[0042] These results surprisingly show that free oxidizing chlorine can dramatically reduce the cure time of this type of UF resin. The results also show that the pH of the sodium hypochlorite solution must be adjusted with acid to gain this advantage, presumably because sodium hypochlorite solutions are highly alkaline which interferes with the acid polymerization reaction during curing. [0043] There was a question related to whether the high level of additional water added from the dilute sodium hypochlorite solution would negatively effect curing times. Therefore, two of the test conditions from Example 2 using ammonium sulfate were repeated with additional water to give moisture content equivalent to the sodium hypochlorite tests shown in Table 2. The results given in Table 3 show that these higher moisture levels had only a minor negative effect on measured cure times.

TABLE 3

Example 4:

[0044] The cure times of the UF resin described in Example 1 as a function of treatment with free oxidizing bromine was investigated in this Example. In order to generate oxidizing bromine, sodium bromide was added to sodium hypochlorite to convert oxidizing chlorine to oxidizing bromine. The oxidant level, expressed as chlorine, was equivalent to the test performed in Example 3. The result is given below in Table 4.

TABLE 4

[0045] These results show that the free oxidizing bromine can also dramatically reduce the cure time of this type of UF resin. The effectiveness of oxidizing bromine is similar to the effectiveness of oxidizing chlorine when both are expressed as Cl₂. Example 5:

[0046] The cure times of the UF resin described in Example 1 as a function of treatment with an oxidizing chlorine donor added in the form of solid 1,3-dichloro- 5,5-dimethyl hydantoin (DCDMH) was investigated in this Example. The oxidant strength of DCDMH is approximately 72% expressed as Cl₂. The results are given below in Table 5. TABLE 5

[0047] These results show that oxidizing chlorine applied in the form of DCDMH reduces the cure time of this type of UF resin to a greater extent than free oxidizing chlorine applied in the form of sodium hypochlorite. DCDMH also outperformed ammonium sulfate. The cure time at 0.50 weight % was equivalent to the shortest cure times measured for ammonium sulfate in Example 2. However, unlike ammonium sulfate, increasing the level of DCDMH resulted in significant reductions in cure time. The 48 seconds cure time, measured with an addition level of 2% DCDMH, is approximately 40% faster than was attainable with ammonium sulfate. Example 6:

[0048] The cure times of the UF resin described in Example 1 as a function of treatment with the carrier molecule for DCDMH, dimethyl hydantoin (DMH), was investigated in this Example. The DMH content of DCDMH is approximately 65%. The result is given below in Table 6.

TABLE 6

[0049] These results show that DMH does not effectively reduce the cure time of this type of UF resin. Therefore, the performance of DCDMH in Example 5 is not due to DMH. The level of DMH in this Example is approximately 50% higher than would be contributed by the highest level of DCDMH tested in Example 5. Example 7:

[0050] The cure times of the UF resin described in Example 1 as a function of treatment with an oxidizing chlorine donor added in the form of solid sodium dichloro isocyanuric acid (Na DCCYA) was investigated in this Example. The oxidant strength of Na DCCYA is approximately 64% expressed as Cl₂. The results are given below in Table 7.

TABLE 7

[0051] These results show that the oxidizing chlorine applied in the form of Na DCCYA reduces the cure time of this type of UF resin to a greater extent than free oxidizing chlorine applied in the form of sodium hypochlorite. Na DCCYA does not reduce cure time to the same extent as DCDMH, perhaps because it is more alkaline. The pH of a 1% Na DCCYA aqueous suspension is 5.8. Example 8:

[0052] The cure time of the UF resin described in Example 1 as a function of treatment with the carrier molecule for Na DCCYA, isocyanuric acid (CYA) was investigated in this Example. The CYA content of Na DCCYA is approximately 59%. The result is given below in Table 8.

[0053] These results show that CYA does not reduce the cure time of this type of UF resin sufficiently to explain the performance of Na DCCYA. The moderate performance observed may be due to the fact that CYA is slightly acidic. The pH of a 1% CYA aqueous suspension is 3.8. Example 9:

[0054] The cure times of the UF resin described in Example 1 as a function of treatment with an oxidizing chlorine donor added in the form of solid trichloro isocyanuric acid (TCCA) was investigated in this example. The oxidant strength of TCCA is approximately 91% expressed as Cl₂. The results are given below in Table 9.

[0055] These results show that the oxidizing chlorine donor, TCCA, reduces the cure time of this type of UF resin to a greater extent than free oxidizing chlorine applied in the form of sodium hypochlorite. TCCA reduces cure time to approximately the same extent as DCDMH when levels are expressed as Cl₂. Example 10:

[0056] The cure times of the UF resin described in Example 1 as a function of treatment with an oxidizing bromine donor added in the form of solid 1,3-dibromo- 5,5-dimethyl hydantoin (DBDMH) was investigated in this Example. The oxidant strength of DBDMH is approximately 50% expressed as Cl₂. The results are given below in Table 10.

TABLE 10

[0057] These results show that the oxidizing bromine donor, DBDMH, reduces the cure time of this type of UF resin to a greater extent than free oxidizing bromine applied in the form of sodium hypochlorite with added sodium bromide as described in Example 4. DBDMH reduces cure time to approximately the same extent as DCDMH and TCCA when levels are expressed as Cl₂. Example 11:

[0058] The cure times of the UF resin described in Example 1 as a function of treatment with a mixture of oxidizing bromine and oxidizing chlorine added in the form of solid l-bromo-3-chloro-5,5-dimethyl hydantoin (BCDMH) was investigated in this Example. The oxidant strength of BCDMH is approximately 59% expressed as Cl₂. The results are given below in Table 11.

TABLE 11

[0059] These results show that the oxidizing chlorine and oxidizing bromine donor, BCDMH, reduces the cure time of this type of UF resin to a greater extent than application of either free chlorine or free bromine as shown in Examples 3 and 4 respectively. BCDMH reduces cure time to approximately the same extent as DBDMH, DCDMH and TCCA when levels are expressed as Cl₂. Example 12:

[0060] The cure times of the UF resin described in Example 1 as a function of treatment with a non-halogen oxidizer, hydrogen peroxide (H₂0₂) in the form of a 27.5% H₂0₂ solution, was investigated in this Example. H₂0₂ has been mentioned as a possible catalyst for UF resin, although no commercial use is presently known. The oxidant strength of H₂0₂ is approximately 208% expressed as Cl₂. Results are shown in Table 12.

TABLE 12

[0061] These results show that hydrogen peroxide reduces the cure time of this type of UF resin. The improvement for the lower levels is approximately the same as seen for Na DCCYA. The performance at the lower levels may be partially explainable because the hydrogen peroxide solution is acidic, the initial pH is 2.75. The longer cure time associated with the higher level may be caused by a pH rise as the cure reaction progresses because oxidizing reactions with H₂0₂ generate alkalinity (e.g. H₂0₂ +2e ^" → 20H ).

[0062] The application of curing agents can be achieved by using different physical forms.

Example 13:

[0063] The cure times of the UF resin described in Example 1 was investigated as a function of treatment with BCDMH encapsulated in a paraffin wax matrix at a level of 20%. The encapsulate was prepared by feeding a stream of molten wax

(melting point of 60°C [140°F]) containing BCDMH to the center of a rotating disk which flings the mixture into the air where droplets freeze into capsules with diameters of approximately 100 microns.

[0064] Treatment of resin with encapsulated curing agent could be advantageous so that curing agent would not need to be added at the time of resin application to a substrate. A mixture of this resin containing wax encapsulate equivalent to 0.5% BCDMH was stable at room temperature for 2 days before solidifying.

[0065] The results show gel times somewhat slower than when treated with solid BCDMH in example 11. This is probably because the wax shell must melt before BCDMH can react with the resin.

Example 14:

[0066] The cure times of the UF resin described in Example 1 as a function of treatment with BCDMH formulated as a 40% aqueous suspension as described by

Yeoman, et. al, see, US Patent 6,281,169; issued August 28, 2001.

[0067] These gel time results are equivalent to those found for treatment with solid BCDMH as described in Example 11.

Example 15:

[0068] The cure times of the UF resin described in Example 1 as a function of treatment with BCDMH formulated as a 10% solution in propylene carbonate.

[0069] The gel time results are equivalent to those found for treatment with solid BCDMH as described in Example 11.

[0070] To determine whether the propylene carbonate solvent contributed to the curing process, a test was performed where only the solvent was used. The level was similar to the lowest level of BCDMH shown in TABLE 15. The result shows that propylene carbonate at this level does not significantly reduce cure time.

[0071] The synergistic behavior of between ammonium sulfate and oxidizing halogen products as curing agents for this UF resin were tested.

Example 16:

[0072] The cure times of the UF resin described in Example 1 as a function of treatment with various levels and ratios of solid BCDMH powder as described in

Example 11 and ammonium sulfate as described in Example 2 are shown in Table

17. TABLE 17

[0073] The results clearly demonstrate synergy between ammonium sulfate and BCDMH at treatment levels of 0.5% to 2% total curing agent. Example 17:

[0074] The cure times of the UF resin described in Example 1 as a function of treatment with various ratios of BCDMH dispersion as described in example 14 and ammonium sulfate as described in Example 2 are shown in Table 18.

TABLE 18

[0075] The results clearly demonstrate synergy between ammonium sulfate and BCDMH at a treatment level of 1% total curing agent. The results are similar to those found in Example 16. Example 18:

[0076] The cure times of the UF resin described in Example 1 as a function of treatment with various ratios of wax encapsulated BCDMH as described in Example 13 and ammonium sulfate as described in Example 2 are shown in Table 19. TABLE 19

[0077] The results clearly demonstrate synergy between ammonium sulfate and BCDMH at a treatment level of 0.5% to 1% total curing agent. As observed in Example 13, the curing times for resin treated with the wax encapsulate tend to be longer than for the other forms of BCDMH tested. Example 19:

[0078] The cure times of the UF resin described in Example 1 as a function of treatment with various levels and ratios of TCCA as described in Example 9 and ammonium sulfate as described in Example 2 are shown in Table 20.

TABLE 20

[0079] The results clearly demonstrate synergy between ammonium sulfate and

TCCA at a treatment levels from 0.5% to 1% total curing agent.

Example 20:

[0080] The cure times of the UF resin described in Example 1 as a function of treatment with the aluminum sulfate was investigated in this example. TABLE 21

[0081] It can be seen that aluminum sulfate is an effective curing agent for this resin. Aluminum sulfate is a known curing agent for UF resins which reduces pH when dissolved in water. The use of aluminum sulfate is limited because the pH can go too low resulting in resin hydrolysis. Example 21:

[0082] The cure times of the UF resin described in Example 1 as a function of treatment with various levels and ratios of solid BCDMH powder as described in example 11 and aluminum sulfate as described in Example 20 are shown in Table 22.

TABLE 22

[0083] The results clearly demonstrate synergy between aluminum sulfate and

BCDMH at treatment levels of 0.25% to 0.5% total curing agent.

Example 22:

[0084] The cure time of the UF resin described in Example 1 as a function of treatment with various ratios of solid TCCA as described in Example 9 and aluminum sulfate as described in Example 20 are shown in Table 23. TABLE 23

[0085] The results clearly demonstrate synergy between aluminum sulfate and TCCA at a treatment levels of 0.5% total curing agent. Example 23:

[0086] The cure time of a different Urea Formaldehyde (UF) resin (received from BASF corporation, BASF K-350) with no curing agent addition was determined as described in the Laboratory Resin Cure Test section above to be 3,238 seconds (53 minutes 58 seconds). This cure time is too long to be used commercially which is consistent with industry practice of adding curing agents to decrease cure times. Example 24:

[0087] The cure times of the UF resin described in Example 23 as a function of treatment with ammonium sulfate levels is shown in Table 24.

TABLE 24

[0088] These results confirm that ammonium sulfate dramatically reduces the cure time of this type of UF resin. Once again the results demonstrate one of the limitations of ammonium salts as curing agents, increasing levels beyond a certain point does not decrease cure times. Compared to the resin described in Example 1, this resin required a somewhat higher level of ammonium sulfate to achieve the same cure rate.

Example 25:

[0089] The cure times of the UF resin described in Example 23 as a function of treatment with free oxidizing chlorine level was investigated in this Example. The source of oxidizing chlorine used was 5.25% sodium hypochlorite solution.

Results are shown in Table 25.

TABLE 25

[0090] These results show the same trend as described in Example 3. Free oxidizing chlorine can dramatically reduce the cure time of this type of UF resin. Example 26:

[0091] The cure times of the UF resin described in Example 23 as a function of treatment with free oxidizing bromine was investigated by this Example. As described in Example 4, adding sodium bromide to sodium hypochlorite generated the oxidizing bromine. The oxidant level, expressed as chlorine, was equivalent to the tests performed in Example 25. The result is given below in Table 26.

TABLE 26

[0092] These results show that free oxidizing bromine can also dramatically reduce the cure time of this type of UF resin. The effectiveness of oxidizing bromine is similar to the effectiveness of oxidizing chlorine when both are expressed as Cl₂.

Example 27:

[0093] The cure times of the UF resin described in Example 23 as a function of treatment with an oxidizing chlorine donor added in the form of solid 1,3-dichloro- 5,5-dimethyl hydantoin (DCDMH) was investigated in this Example. The result is given below in Table 27.

TABLE 27

[0094] These results show that oxidizing chlorine applied in the form of DCDMH reduces the cure time of this type of UF resin to a greater extent than free oxidizing chlorine applied in the form of sodium hypochlorite. DCDMH also outperformed ammonium sulfate at a concentration of 2% or above. Example 28:

[0095] The cure times of the UF resin described in Example 23 as a function of treatment with an oxidizing chlorine donor added in the form of solid sodium dichloro isocyanuric acid (Na DCCYA) was investigated in this Example. The results are given below in Table 28.

TABLE 28

[0096] These results show that the oxidizing chlorine applied in the form of Na DCCYA reduces the cure time of this type of UF resin similar to the oxidizing free chlorine applied in the form of sodium hypochlorite. Na DCCYA does not reduce cure time to the same extent as DCDMH, perhaps because it is more alkaline. The pH of a 1% Na DCCYA aqueous suspension is 5.8. Example 29:

[0097] The cure times of the UF resin described in Example 23 as a function of treatment with an oxidizing chlorine donor added in the form of solid trichloro isocyanuric acid (TCCA) was investigated in this example. The results are given below in Table 29. TABLE 29

[0098] These results show that the oxidizing chlorine donor, TCCA, reduces the cure time of this type of UF resin to a greater extent than free oxidizing chlorine applied in the form of sodium hypochlorite. TCCA reduces cure time to approximately the same extent as DCDMH when levels are expressed as Cl₂. Example 30:

[0099] The cure times of the UF resin described in Example 23 as a function of treatment with an oxidizing bromine donor added in the form of solid 1,3-dibromo- 5,5-dimethyl hydantoin (DBDMH) was investigated in this Example. The results are given below in Table 30.

TABLE 30

[00100] This results show that the oxidizing bromine donor, DBDMH, reduces the cure time of this type of UF resin to a greater extent than free oxidizing bromine applied in the form of sodium hypochlorite with added sodium bromide as described in Example 4. DBDMH reduces cure time to approximately the same extent as DCDMH and TCCA when levels are expressed as Cl₂. Example 31 :

[00101] The cure times of the UF resin described in Example 23 as a function of treatment with a mixture of oxidizing bromine and oxidizing chlorine added in the form of sold l-bromo-3-chloro-5,5-dimethyl hydantoin (BCDMH) was investigated in this Example. The results are given below in Table 31. TABLE 31

[00102] These results show that the oxidizing chlorine and oxidizing bromine donor, BCDMH, reduces the cure time of this type of UF resin to a greater extent than application of either free chlorine or free bromine as shown in Examples 25 and 26, respectively. BCDMH reduces cure time to approximately the same extent as DBDMH, DCDMH and TCCYA when levels are expressed as Cl₂. Example 32:

[00103] The cure time of the UF resin described in Example 23 as a function of treatment with various ratios of solid BCDMH powder as described in example 31 and ammonium sulfate as described in Example 24 are shown in Table 32.

TABLE 32

[00104] The results clearly demonstrate synergy between ammonium sulfate and BCDMH at a treatment level of 1% total curing agent. Example 33:

[00105] The cure times of a melamine coating resin (received from Georgia Pacific corporation, GP542D59) with no curing agent addition was determined as described in the Laboratory Resin Cure Test section above to be longer than 5 hours. This cure time is too long to be used commercially which is consistent with industry practice of adding curing agents to decrease cure times. Example 34:

[00106] The cure times of the melamine coating resin described in Example 33 as a function of treatment with ammonium sulfate levels is shown in Table 33.

[00107] These results confirm that ammonium sulfate dramatically reduces the cure time of this type of melamine resin.

Example 35:

[00108] The cure times of the melamine coating resin described in Example 33 as a function of treatment with free oxidizing chlorine level was investigated in this

Example. The source of oxidizing chlorine used was 5.25% sodium hypochlorite solution. The result is shown in Table 34.

TABLE 34

[00109] These results show that free oxidizing chlorine has no measured effect at reducing the cure time of this type of melamine coating resin. The results also show that the pH adjustment of the sodium hypochlorite solution with acid as described in Example 3 does not gain an advantage. Example 36:

[00110] The cure times of the melamine coating resin described in Example 33 as a function of treatment with free oxidizing bromine was investigated in this Example. To generate oxidizing bromine, sodium bromide was added to sodium hypochlorite to convert oxidizing chlorine to oxidizing bromine, as described in Example 4. The oxidant level, expressed as chlorine, was equivalent to the tests performed in Example 35. The result is given below in Table 35.

TABLE 35

Wt% Free Oxidizing bromine Cure Time (Seconds)

0.59 as C-2 (adjusted pH = 7.0) 232

[00111] These results surprisingly shows that free oxidizing bromine can dramatically reduce the cure time of this type of melamine resin. It also shows that free oxidizing bromide is more effective than oxidizing chlorine. Example 37:

[00112] The cure times of the melamine coating resin described in Example 33 as a function of treatment with an oxidizing chlorine donor added in the form of solid l,3dichloro5,5dimethyl hydantoin (DCDMH) was investigated in this Example. The result is given below in Table 36.

TABLE 36

[00113] These results show that oxidizing chlorine applied in the form of DCDMH reduces the cure time of this type of melamine resin whereas free oxidizing chlorine applied in the form of sodium hypochlorite had no measurable effect.

Example 38:

[00114] The cure times of the melamine coating resin described in Example 33 as a function of treatment with an oxidizing chlorine donor added in the form of solid trichloro isocyanuric acid (TCCA) was investigated in this Example. The results are given below in Table 37.

[00115] These results show that the oxidizing chlorine donor, TCCA, reduces the cure time of this type of melamine resin whereas free oxidizing chlorine applied in the form of sodium hypochlorite had no measurable effect. Example 39:

[00116] The cure times of the melamine coating resin described in example 33 as a function of treatment with an oxidizing bromine donor added in the form of solid l,3dibromo5,5dimethyl hydantoin (DBDMH) was investigated in this Example. The result is given below in Table 38.

TABLE 38

[00117] These results show that the oxidizing bromine donor, DBDMH, reduces the cure time of this type of melamine resin to a greater extent than the oxidizing chlorine donor, DCDMH, as described in Example 37. This phenomenon is consistent with the results obtained from treatment of this resin with free chlorine and free bromine as described in Examples 35 and 36. Example 40:

[00118] The cure times of the melamine coating resin described in Example 33 as a function of treatment with a mixture of oxidizing bromine and oxidizing chlorine added in the form of solid l-bromo-3-chloro-5,5-dimethyl hydantoin (BCDMH) was investigated in this Example. The results are given below in Table 39.

[00119] These results show that the oxidizing chlorine and oxidizing bromine donor, BCDMH, reduces the cure time of this type of UF resin to a greater extent than application of either free chlorine or free bromine as shown in Examples 35 and 36, respectively.

Example 41:

[00120] The cure times of the melamine coating resin described in Example 33 as a function of treatment with BCDMH formulated as a 10% solution in propylene carbonate. The results are given below in Table 40.

[00121] The results for BCDMH solution are similar to those found for treatment of this resin with solid BCDMH as described in Example 40. [00122] To determine whether the propylene carbonate solvent contributed to the curing process, a test was performed where only the solvent was used. The level was similar to the lowest level of BCDMH shown in Table 40. The result shows that propylene carbonate at this level does not significantly reduce cure time.

TABLE 41

Wt% as Propylene Carbonate Cure Time (Seconds)

5.00 [0.56] >600

Example 42:

[00123] The cure times of the melamine coating resin described in Example 33 as a function of treatment with various levels and ratios of solid BCDMH powder as described in Example 40 and ammonium sulfate as described in Example 34 are shown in Table 42.

TABLE 42

[00124] The results clearly demonstrate synergy between ammonium sulfate and BCDMH at treatment levels of 1% to 2% total curing agent. Resin Comparisons for subsequent examples.

[00125] The UF resin tested in Examples 1 through 21, GP487D45, was not available when the testing described in Examples 42, 44, 47, 48 and 49 was performed. A very similar UF resin, GP487D39, was used in these examples. The laboratory gel times shown below confirm that these resins respond similarly to ammonium sulfate, BCDMH and both exhibit synergistic behaviors with blends of ammonium sulfate and BCDMH. In general, GP487D39 UF resin appeared to be slightly less reactive than GP487D45 UF resin.

[00126] The cure time of GP487D39 UF resin with no curing agent addition was found to be 2,910 seconds (48 minutes 30 seconds) comparable to 2,688 seconds (44 minutes 48 seconds) found for GP487D45 in Example 1.

TABLE 43 Gel Time Comparisons Using Ammonium Sulfate

TABLE 44

TABLE 45 Gel Time Comparisons Using Solid BCDMH/(NH₄)₂SO₄ Blends

[00127] The DSC of curing resins was measured. Example 43:

[00128] The DSC spectra of a curing Urea Formaldehyde (UF) resin (received from Georgia Pacific Resins, GP487D39) was performed to determine exotherm peak onset and offset temperatures as well as the heat of reaction. The synergistic interaction between ammonium sulfate and BCDMH dispersion (as described in Example 14) was tested. The total curing agent level was maintained a 1.17% and the ratio of the individual agents was varied. The results are shown in Table 46. TABLE 46

[00129] The results clearly demonstrate synergy between ammonium sulfate and BCDMH at a treatment level of 1.17% total curing agent. The data shows that the exotherm occurs at a significantly lower temperature (onset and offset) for the blend than for either curing agent alone. These results also show similar enthalpy values indicating a similar degree of resin hydrolysis associated with the lower cure temperatures. For this treatment level in this resin the curing exotherm occurs at a lower temperature for BCDMH than for ammonium sulfate. Example 44:

[00130] The DSC spectra of a curing Urea Formaldehyde (UF) resin (received from BASF Corporation, K350) was performed to determine exotherm peak onset and offset temperatures as well as the heat of reaction. The synergistic interaction between ammonium sulfate and BCDMH dispersion (as described in Example 14) was tested. The total curing agent level was maintained at 1.17% and the ratio of the individual agents was varied. The results are shown in Table 47.

TABLE 47

[00131] The results clearly demonstrate synergy between ammonium sulfate and BCDMH at a treatment level of 1.17% total curing agent. The data shows that the exotherm occurs at a significantly lower temperature (onset and offset) for the blend than for either curing agent alone. These results also show similar enthalpy values indicating a similar degree of resin hydrolysis associated with the lower cure temperatures. For this treatment level in this resin the curing exotherm occurs at a lower temperature for ammonium sulfate than for BCDMH. Viscosity Measured Hardening Times Example 45:

[00132] The hardening times for the Urea Formaldehyde (UF) resin (received from Georgia Pacific Resins, GP487D39) was performed to determine time and temperature associated with curing agent addition. The synergistic interaction between ammonium sulfate and BCDMH dispersion (as described in Example 14) was tested. The total curing agent level was maintained at 1.17% and the ratio of the individual agents was varied. The results are shown in Table 48.

TABLE 48

[00133] The results clearly demonstrate synergy between ammonium sulfate and BCDMH at a treatment level of 1.17% total curing agent. The data shows that hardening occurs at a much shorter time for the blend than for either curing agent alone. This is also reflected in lower temperature cure because the temperature of the thermostated viscometer increases with time. For this treatment level in this resin the BCDMH hardens more quickly than ammonium sulfate. Example 46:

[00134] The hardening times for a Urea Formaldehyde (UF) resin (received from BASF Corporation, K350) was performed to determine time and temperature associated with curing agent addition. The synergistic interaction between ammonium sulfate and BCDMH dispersion (as described in Example 14) was tested. The total curing agent level was maintained at 1.17% and the ratio of the individual agents was varied. The results are shown in Table 49.

TABLE 49

[00135] The results clearly demonstrate synergy between ammonium sulfate and BCDMH at a treatment level of 1.17% total curing agent. The data shows that hardening occurs at a much shorter time for the blend than for either curing agent alone. This is also reflected in the lower temperature because the temperature of the thermostated viscometer increases with time. For this treatment level in this resin the ammonium sulfate treated resin hardens more quickly than BCDMH. Practical application Example 47:

[00136] The performance of BCDMH (in the form of a wax encapsulate) was compared to ammonium sulfate as an adhesive for finish foil application. A mixture of E-2 Urea Formaldehyde resin and catalyst was spread on both sides of particleboard, paper was unrolled onto the top and bottom faces of the board before entering the heated hydraulic press. Surface temperature of the press in contact the coating foil faces was 145°C (293°F). The hot press closes and pressure is applied for a period of time sufficient to cause the paper to adhere to the board. When the press opens, the coated board is trimmed and stacked. [00137] The wax encapsulate product was produced in a slightly different fashion than described in Example 13. A molten mixture of 24.5% solid BCDMH in paraffin wax with a melting point of 60°C (140°F) was aspirated with pre-heated air through a spray nozzle. The droplets froze at ambient temperature to form the capsules. [00138] The shortest press time possible for the comparative treatments are given in Table 50.

[00139] A much shorter press time was achievable when the catalyst was BCDMH encapsulated in paraffin wax than when ammonium sulfate was used as the catalyst as shown in the Table 50.

TABLE 50

[00140] Treatment with BCDMH reduced the minimum press time by a factor of two compared to ammonium sulfate. Particleboard - Pilot Panel Manufacture Example 48:

[00141] Particleboard panels were made in a pilot press as described in the Methods section. The total curing agent level in the core resin was maintained at 1.22% and the ratio of the individual agents was varied. The synergistic interaction between ammonium sulfate and BCDMH dispersion (as described in Example 14) was tested at a press time of 117 seconds. The results are shown in Table 51.

TABLE 51

[00142] The board thickness results clearly demonstrate synergy between ammonium sulfate and BCDMH at a treatment level of 1.22% total curing agent for this press time. Board thickness values close to the nominal thickness of 16.0 mm indicate that when the press opened, the internal bond was greater than the internal pressure due to steam production. Under these conditions BCDMH did not exhibit a lower board thickness than ammonium sulfate. The blend of these curing agents exhibited synergy because there was lower board thickness measured for blends than would be expected by additive performance. [00143] The internal bond values listed were determined after standard conditioning of samples from the boards produced. The minimum internal bond specifications for grades of medium density particleboard (density between 640 and 800 kg/m³) including Ml, MS, M2, M3, PBU, D2 and D3 range from 0.40 to 0.55 MPa (58 to 80 psi). All of the boards produced in this example were well above these requirements. Table of particleboard grade specifications can be found at the internet address http://www.fpl.fs.fed.us/PDComp/ handbook/particle.htm, part of the Forest Product Laboratory Web Site Example 49:

[00144] Particleboard panels were made in a pilot press as described in the Methods section. In these tests the core resin was treated with either 1.22% ammonium sulfate or 1.22% ammonium sulfate with an additional 0.41% BCDMH using the dispersion as described in example 14. Board properties were measured as a function of press time. The results are given in Table 52.

TABLE 52

[00145] The data shows that the addition of BCDMH to ammonium sulfate at these levels can result in less springback from the nominal thickness. The data also shows that below a press time of about 92 seconds the measured internal bond is below allowable standards for boards treated with ammonium sulfate alone. Whereas the boards treated with the same level of ammonium sulfate and additional BCDMH exhibited acceptable internal bond values even with press times down to 80 seconds. Example 50:

[00146] Particleboard panels were made in a pilot press as described in the Methods section. In these tests the core resin was treated with either 1.22% ammonium sulfate or 1.22% ammonium sulfate with an additional 0.41% BCDMH using the dispersion as described in Example 14. Boards were made using a press time of 117 seconds. Board properties were measured as a function of % core resin. The results are given in Table 53.

TABLE 53

[00147] The data shows that the addition of BCDMH to ammonium sulfate at these levels can result in less springback from the nominal thickness as the level of core resin relative to core wood weight is reduced. Resin costs represent a significant portion of the manufacturing costs for composite boards. The internal bond values were at, or above, minimum standards for some grades for all of the boards tested.

[00148] The first 42 examples describe the results of laboratory cure time testing for two UF resins, GP487D45 and BASF K-350, and one MF resin, GP542D59. Between Examples 42 and 43, testing results for a third UF resin, GP487D39, was compared to GP487D45 described in Examples 1, 2, 11 and 16 to demonstrate that these two UF resins behave similarly with no curing agent and with (NH4)2S04, BCDMH and synergistic combinations of (NH4)2S04 and BCDMH. This was required because GP487D45 was not available for the advanced testing described in Examples 43 through 50. Table 54 which follows summarizes the test conditions for these examples.

[00149] In Example 47 it was shown that the minimum press times when wax encapsulated BCDMH was used as a curing agent was about 50% less than when (NH4)₂S0₄ was used as a curing agent for a production scale finish foil application. No other studies were performed on this on- site prepared UF resin. [00150] Table 55 which follows summarizes the conditions for the advanced testing performed at the Fraunhofer Institute described in Examples 43 through 50 (excluding Example 47 described above) for two UF resins, GP487D39 and BASF K-350. Differential Scanning Calorimetry and Resin Hardening (Viscosity) studies were performed on both of these resins using (NH4)₂S0₄, BCDMH and synergistic combinations of (NH4)₂S0₄ and BCDMH. The conditions for preparation of particleboard panels made on a pilot press using GP487D39 UF resin is described in Examples 48, 49 and 50.

Table 55 - Advanced Testin

[00151] Example 47 demonstrated that for a finish foil application using a UF resin prepared at the use site, the minimum press time when using encapsulated BCDMH was nearly 50% shorter than when Particleboard Panel Testing for Reduced Press

Time (NH₄)₂S0₄ was used.

[00152] Further variations and modifications of the foregoing will be apparent to those skilled in the art and are intended to be encompassed by the claims appended hereto.

Claims

We claim:

1. A process for making an article from an amino resin comprising mixing an amino resin with a halogenated catalyst in a sufficient amount to form a reaction mass, shaping the reaction mass and heating said reaction mass to produce a cured amino resin article.

2. The process according to claim 1 wherein the catalyst is a member

selected from the group consisting of l,3-dichloro-5,5-dimethylhydantoin

(DCDMH), l,3-dibromo-5,5-dimethylhydantoin (DBDMH), l-bromo-3-chloro-

5,5-dimethylhydantoin (BCDMH), and l-bromo-3-chloro-5-methyl-5-

ethylhydantoin (BCMEH).

3. The process according to claim 1 wherein the catalyst is a member

selected from the group consisting of sodium dichloroisocyanurate, sodium

dichloroisocyanurate dihydrate, potassium dichloroisocyanurate,

dichloroisocyanuric acid (DCCYA), trichloroisocyanuric acid (also known as

trichloro-s-triazinetrione, TCCA), and the mixed complex of 4 potassium

dichloroisocyanurate to 1 trichloroisocyanuric acid.

4. The process according to claim 1 wherein the catalyst is a member

selected from the group consisting of chloro-substituted glycoluril and bromo-

substituted glycoluril.

5. The process according to claim 1 wherein the catalyst is a member

selected from the group consisting of Cl₂, lithium hypochlorite (LiOCl), calcium hypochlorite ((Ca(0Cl)₂), sodium hypochlorite (NaOCl), hypochlorous acid

(HOC1), and chlorine dioxide (C10₂).

6. The process according to claim 1 wherein the catalyst is a member

selected from the group consisting of Br₂, hypobromous acid (HOBr), sodium

hypobromite (NaOBr), BrCl, a bromide activated by Cl₂, NaOCl, or 0_3ι wherein

the bromide is sodium bromide, potassium bromide, magnesium bromide, calcium

bromide, zinc bromide, tetraethylammonium bromide, tetramethylammonium

bromide, or ammonium bromide.

7. The process according to claim 1 wherein the catalyst is a member

selected from the group consisting of NHC1₂, NH₂C1, and halogenated hydantoins.

8. The process according to claim 1 wherein the catalyst is a member

selected from the group consisting of N-bromo and N-chlorosulfamates.

9. The process according to claim 1 wherein the catalyst is a combination

of a halogenated catalyst and an ammonium salt of a mineral acid.

10. The process according to claim 1 wherein the amino resin is a member

selected from the group consisting of urea-formaldehyde, melamine-formaldehyde

and melamine-urea-formaldehyde.

11. A process for making a wood composite article comprising providing a comminuted wood product, impregnating said comminuted wood product with a sufficient amount of a synthetic organic resin to substantially cover said comminuted wood to form a reaction mass, heating said reaction mass in the presence of a halogenated catalyst to produce a cured wood composite article.

12. The process according to claim 11 wherein the catalyst is a member

selected from the group consisting of l,3-dichloro-5,5-dimethylhydantoin

(DCDMH), l,3-dibromo-5,5-dimethylhydantoin (DBDMH), l-bromo-3-chloro-

5,5-dimethylhydantoin (BCDMH), and l-bromo-3-chloro-5-methyl-5-

ethylhydantoin (BCMEH).

13. The process according to claim 11 wherein the catalyst is a member

selected from the group consisting of sodium dichloroisocyanurate, sodium

dichloroisocyanurate dihydrate, potassium dichloroisocyanurate,

dichloroisocyanuric acid (DCCYA), trichloroisocyanuric acid (also known as

trichloro-s-triazinetrione, TCCA), and the mixed complex of 4 potassium

dichloroisocyanurate to 1 trichloroisocyanuric acid.

14. The process according to claim 11 wherein the catalyst is a member

selected from the group consisting of chloro- substituted glycoluril and bromo-

substituted glycoluril.

15. The process according to claim 11 wherein the catalyst is a member

selected from the group consisting of Cl₂, lithium hypochlorite (LiOCl), calcium

hypochlorite ((Ca(OCl)₂), sodium hypochlorite (NaOCl), hypochlorous acid

(HOC1), and chlorine dioxide (C10₂).

16. The process according to claim 11 wherein the catalyst is a member

selected from the group consisting of Br₂, hypobromous acid (HOBr), sodium

hypobromite (NaOBr), BrCl, a bromide activated by Cl₂, NaOCl, or 0_3, wherein the bromide is sodium bromide, potassium bromide, magnesium bromide, calcium

bromide, zinc bromide, tetraethylammonium bromide, tetramethylammonium

bromide, or ammonium bromide.

17. The process according to claim 11 wherein the catalyst is a member

18. The process according to claim 11 wherein the catalyst is a member

selected from the group consisting of N-bromo and N-chlorosulfamates.

19. The process according to claim 11 wherein the catalyst is a

combination of a halogenated catalyst and an ammonium salt of a mineral acid.

20. The process according to claim 11 wherein the amino resin is a

member selected from the group consisting of urea-formaldehyde, melamine-

formaldehyde and melamine-urea-formaldehyde.

21. A process for making a particleboard panel having a core and at least

one surface layer comprising providing wood chips of at least two sizes, a larger

chip for the core and a smaller chip for the surface layer, blending chips for the

core with a sufficient amount of organic synthetic resin to cover the chips for the

core and produce a first blend, blending chips for the surface layer with a sufficient

amount of synthetic organic resin to coat at least part of a surface of the smaller

chip to form a second blend, mixing a sufficient amount of a halogenated catalyst

with said first and second blend to permit curing of said resin, placing the resulting mixture in a press, heating said press to a surface temperature of at least 200°C and

compressing said mixture to a desired thickness.

22. The process according to claim 21 wherein the catalyst is a member

selected from the group consisting of l,3-dichloro-5,5-dimethylhydantoin

(DCDMH), l,3-dibromo-5,5-dimethylhydantoin (DBDMH), l-bromo-3-chloro-

5,5-dimethylhydantoin (BCDMH), and l-bromo-3-chloro-5-methyl-5-

ethylhydantoin (BCMEH).

23. The process according to claim 21 wherein the catalyst is a member

selected from the group consisting of sodium dichloroisocyanurate, sodium

dichloroisocyanurate dihydrate, potassium dichloroisocyanurate,

dichloroisocyanuric acid (DCCYA), trichloroisocyanuric acid (also known as

trichloro-s-triazinetrione, TCCA), and the mixed complex of 4 potassium

dichloroisocyanurate to 1 trichloroisocyanuric acid.

24. The process according to claim 21 wherein the catalyst is a member

selected from the group consisting of chloro- substituted glycoluril and bromo-

substituted glycoluril.

25. The process according to claim 21 wherein the catalyst is a member

hypochlorite ((Ca(OCl)₂), sodium hypochlorite (NaOCl), hypochlorous acid

(HOC1), and chlorine dioxide (C10₂).

26. The process according to claim 21 wherein the catalyst is a member

selected from the group consisting of Br₂, hypobromous acid (HOBr), sodium

hypobromite (NaOBr), BrCl, a bromide activated by Cl₂, NaOCl, or 0_3, wherein

said bromide is sodium bromide, potassium bromide, magnesium bromide, calcium

bromide, zinc bromide, tetraethylammonium bromide, tetramethylammonium

bromide, or ammonium bromide.

27. The process according to claim 21 wherein the catalyst is a member

selected from the group consisting of NHC1₂ NH₂C1, and halogenated hydantoins.

28. The process according to claim 21 wherein the catalyst is a member

selected from the group consisting of N-bromo and N-chlorosulfamates.

29. The process according to claim 21 wherein the catalyst is BCDMH.

30. The process according to claim 21 wherein the catalyst is encapsulated

in paraffin wax.

31. The process according to claim 21 wherein the catalyst is encapsulated

in paraffin wax.

32. The process according to claim 21 wherein the catalyst is a

combination of a halogenated catalyst and an inorganic mineral acidt salt of

ammonia.

33. The process according to claim 21 wherein the salt is chloride, nitrate

or sulfate.

34. The process according to claim 21, wherein said organic synthetic

resin is an amino resin.

35. The process according to claim 34, wherein said amino resin is a

member selected from the group consisting of urea-formaldehyde, melamine-

formaldehyde and melamine-urea-formaldehyde.