SI22167A - Water-soluble melamine urea formaldehyde binder for mineral fibres - Google Patents

Abstract

The invention relates to the process of manufacture of a partly etherified water-soluble melamine formaldehyde resin, to the manufacture of a binder for mineral fibres on the basis of this resin, to the method for production of a mineral-fibre product bound by this binder, and to the product made of mineral fibres, which comprises mineral fibres in contact with the cured composition of the above mentioned binder. According to the invention, condensation and etherification are conducted in a single-stage process under atmospheric pressure in such a way that the pH value of the mixture of melamine (0.5 - 1.5 moles), urea (0.5 - 1.5 moles) and formaldehyde (30 - 50 % solution in water, 1.6 - 2.6 moles per mole of combined amines) is adjusted to 8.0 - 11 and the mixture heated during intensive mixing to 80 up to 100 degrees Celsius, after which the reaction is taking place in the reactor under reflux conditions for 100 up to 300 minutes, and this under checking of hydrophobicity, viscosity and/or index of refraction. The process of manufacture of standard thermal or sound insulation materials is characterized in that the binder is applied in amounts of 0.3 - 10 % on the weight of the bound mineral fibre product, between 10 and 30 % in the case of HDT (high density) panels and 20 - 40 % in the case of composite products made of the mineral fibre reinforced binder, that a catalyst is added to the binder directly prior to its entering into dosing pumps which apply the binder by spraying immediately after defibration of a molten mineral material, that the temperature in the settling chamber lies under the temperature at the beginning of the setting of the resin, and that the thus formed layer of mineral fibres is cured in a curing chamber, where hot air at temperatures of 200 - 400 degrees Celsius is blown through the mineral wool layer.

Description

Water-soluble urea formaldehyde binder for mineral fibers

The invention relates to a process for the manufacture of a partially etched water-soluble melamine urea formaldehyde resin, the manufacture of a mineral fiber binder based on this resin, to a method for the manufacture of a bonded mineral fiber product with this binder and to a mineral fiber product comprising mineral fibers in contact with the stitched composition of the binder mentioned above.

Mineral fiber products typically contain mineral fibers such as, for example, mineral fibers. Artificial fiberglass (MMVF), glass fiber, ceramic fiber, basalt fiber, slag and rock wool, bonded together with a cured thermoplastic or most commonly duroplastic polymeric binder material. For use in thermal or acoustic insulation products, mineral fiber plywood is usually produced by converting the melt from the corresponding raw materials into fibers according to a conventional process, such as e.g. by a process of rapidly rotating perforated vessels or by a cascading rotor process. The fibers are blown into the collecting chamber and, when formed while still hot, are wetted with a binder solution and randomly loaded as a layer or net onto a conveyor belt. The fiber layer is then transported to a curing chamber where it is blown with heated air to harden the binder and rigidly bond the mineral fibers together.

Binder-coated fibers are often too expensive for users, and expensive binder resins are usually the determining price factor. Because of their excellent price / performance factor, phenol formaldehyde resins have typically been selected in the past, which can be economically produced and can be modified with urea before being used as a binder, which is an additional inexpensive binder.

However, as legislators have been reducing emissions of volatile organic components (VOCs) very much in recent years, and as legislation on the use of phenol-containing preparations in Europe has intensified, much effort has been put into extensive research into alternative phenol-free binders.

Based on these studies, quite a few phenolic binder compositions have emerged, e.g. binder based on polycarboxy polymers and polyols.

-2 Another group of phenol-free binders for mineral fibers are the products of the addition / elimination reactions of aliphatic and aromatic anhydrides with alkanolamines. These mineral fiber binders have excellent bonding properties, but they require expensive raw materials and, above all, a high proportion of expensive anhydride reagent to achieve the desired water solubility, cure rate and thickening density.

The melamine-formaldehyde resins known so far would meet the requirements for a mineral fiber binder in terms of flammability and reactivity. So far, the synthesis of water-soluble melamine-urea resins is well known in the art and can be divided into two groups.

A typical method of the first group is that melamine, urea and formaldehyde in a molar ratio of 1: (0 - 2): (1.3 - 4) is heated to 70-90 ° C while stirring, reacting at pH 6.5 to 8.5 until reached the desired degree of polycondensation, as measured by viscosity and / or hydrophobicity, or refractive index. It usually takes 3 to 10 hours to synthesize. Such a process mainly synthesized wood adhesives and papyrus impregnation resins.

A typical process from the second group is that first react melamine and formaldehyde in a ratio of 1: (3 - 10) at pH 8 - 10 and temperature 60 - 80 ° C. Then 10 to 50 molar parts of methanol are added, the temperature is lowered to 30 to 60 ° C, and the pH is lowered to 1 to 6. The reaction is led to the desired degree of etching and polycondensation, and then the excess solvent is distilled off. Such a process mainly synthesizes water-soluble resins for varnishes.

The resins in the first group have good enough adhesive properties, do not have a large amount of combustible components and are suitable for bonding mineral fibers, but they do not have high water-solubility and have short stability, which makes it impossible to use them in existing technologies of production of mineral fiber products.

The resins in the second group have good durability and high water solubility, as well as satisfactory adhesive properties, but they have a higher proportion of combustible components, and the synthesis process is expensive, so they are not suitable as a mineral fiber binder.

So far, this problem of mineral fiber binder has been solved by producing mineral fiber products with very low binder content, approximately 1%, for use at higher temperatures (above 200 ° C), which has resulted in very poor mechanical properties. products, manipulation issues, and major ejection.

The object of the present invention is to provide a phenol-free binder, which is particularly suitable for mineral fiber bonding, which will have excellent bonding properties, especially adequate speed and curing power, to be well soluble in water and have good dilution and can be economically produced from less expensive raw materials.

It is a further object of the present invention to provide a mineral fiber product in which the mineral fibers are bonded to a woven phenol-free binder of the invention.

According to the invention, the problem is solved according to independent claims.

The production of a partially etched water-soluble melamine urea formaldehyde binder for mineral fibers is characterized by the condensation and etching in a one-step process at pH 8 to 11, under atmospheric pressure and in the temperature range 80 to 100 ° C with control of hydrophobicity, viscosity and / or the refractive index.

According to the first object of the present invention, a base for a phenol-free aqueous binder is prepared: a melamine urea formaldehyde resin that meets the technological requirements for a mineral fiber binder, is water-soluble, has good mineral-fiber binder and is flame retardant as a binder.

The process of making melamine formaldehyde resin and the binder according to the invention according to the invention, in comparison with the known melamine formaldehyde resins, additionally satisfies all other requirements, that is, it is water-soluble and, as a hardened binder, water-repellent, at the same time sufficiently reactive, with good adhesion to mineral fibers, and not significantly more expensive than phenolic resin for this purpose.

According to a further aspect of the present invention, there is provided a method for the production of bonded mineral fiber products, comprising the steps of contacting a mineral fiber or mineral fiber product with an aqueous binder without phenol of the invention as described above, and curing the composition of the binder.

According to a further aspect of the present invention, a mineral fiber product is prepared which includes mineral fibers in contact with the cured binder composition of the invention.

-4Description of the invention

An inventive synthesis of the melamine urea partially ethereal formaldehyde resin, comprising the etching process in an alkaline pH range of 8 to 11 and a temperature range of 80-120 ° C.

The resin obtained has the following properties: it is completely water-soluble, contains a high percentage of nitrogen, and does not eliminate harmful components in ecologically and technologically unfavorable quantities during curing and drying.

The hardened resin binds mineral fibers well, is non-combustible and water repellent. The thermal decomposition of the cured resin is slow and uniform over a temperature range of 240 to 580 ° C, enabling the production of mineral fiber panels containing this resin as a binder base in such a way that these panels have special thermal resistance and non-combustibility properties.

The invention will be described in embodiments.

Example 1:

Condensation and etching are conducted in a one-step process at atmospheric pressure under reflux conditions. Mixtures of melamine (0.5-1.5 moles), urea (0.5-1.5 moles) and formaldehyde (40% aqueous solution, 1.6-2.6 moles per mole of combined amines) and methanol (2-3 moles per mole of amines) were adjusted to pH 8.5 - 10 and heated to 80-100 ° C during vigorous stirring. In a reactor under reflux conditions, the reaction takes 100 to 300 minutes. Samples are taken during the reaction and the pH, viscosity, refractive index and hydrophobicity of the resin are measured. The pH is best regulated upwards with the addition of NaOH, KOH, or soda, and the downstream is best adjusted with the addition of nitric, phosphoric or formic acid.

The hydrophobicity of the resin is determined by measuring the number of parts of 20% aqueous sodium acetate solution by which it is possible to dilute 1 part of the resin at 20 ° C without causing turbidity. When the hydrophobicity of the resin measured in the above procedure reaches a value of 2.2 to 2.8, the pH is set to 9.5 to 10.5 and the excess solvent is vacuum-distilled so that the resin contains 50-60% of the dry matter.

-5The resin obtained is completely water-soluble, with a pH of 9.5 to 10 dry matter of 50 to 60% and a viscosity of 52% of dry matter of 27-40 cPas.

The resin is clear, transparent, under 100 Apha. It retains its basic properties at 20 ° C for at least 14 days. B resin time at 180 ° C is 60-100 s.

Example 2:

Raw materials are dosed into a stainless steel chemical reactor equipped to work under pressure of up to 10 bar as in Example 1. During intense stirring, the reaction is conducted at pH 8.5 to 10 and temperature 90 to 110 C. The pressure in the closed reactor increases to 1 to 5 bar. During the reaction, the pH, viscosity, refractive index and hydrophobicity of the resin were measured as in Example 1. When the first insolubility of the reaction mixture in sodium acetate solution (20%) was achieved, the reaction mixture was cooled to reflux at atmospheric pressure and continued as in Example 1.

The resulting resin is completely water-soluble, with a pH of 9.5 to 10 dry matter of 50 to 60% and a viscosity of 52% of dry matter of 27-40 cPas. The resin is clear, transparent, under 100 Apha. It retains its basic properties at 20 C for at least 30 days. B resin time at 180 C is 60-100 s.

The resin binder thus obtained was used in the process of industrial production of insulating boards as a substitute for the phenolic binder. The resulting plates had mechanical and insulating properties identical or similar to those made with a phenolic binder. However, the thermal resistance of the panels was significantly better, so that it was evident from the investigations that the insulating material obtained by such a process could be considered non-combustible. In the described method of manufacturing insulating panels, only small amounts of formaldehyde and traces of methanol are released, while in the classical process using a phenolic binder significant quantities of formaldehyde and phenol and traces of methanol are released into the atmosphere so that the described process is more environmentally friendly than the classical process using phenolic resins. The resulting resin is completely water-soluble, contains a high percentage of nitrogen, is cured, non-combustible, and does not exclude hazardous components in ecologically and technologically unfavorable quantities during curing and drying. The hardened resin binds mineral fibers well, is non-combustible and water repellent. The thermal decomposition of the cured Resin is slow and steady in the temperature range 240 ° C to 580 ° C, which allows the production of mineral fiber panels containing this resin as the main constituent of the binder. These panels have special properties in terms of thermal resistance and non-combustibility.

-6 As a curing catalyst for melamine urea formaldehyde binders can be used which release the acidic component when heated. These may be acids, acid salts of inorganic acids, or adducts of organic acids and amines.

Typical representatives of the first group are formic acid, hydrochloric acid, nitric acid, the second groups are ammonium sulfate, ammonium nitrate, ammonium chloride, and the third is the monoethanolamide of paratoluenesulfonic acid, the morpholinium salt of paratoluenesulfonic acid, etc. The function of the catalyst is to adjust the reactivity of the binder so that it binds on the fibers during the formation of the layer in the curing chamber, and that the polymerization under the conditions of fabrication of the fiber product proceeds to a utq of one and crosslinked melamine urea formaldehyde polymer.

Other suitable additives to the binder are silane-based binders, preferably aminopropylsiloxanes, thermal stabilizers, UV stabilizers, surfactants, fillers such as clay, silicates and magnesium sulfate, pigments, hydrophobic agents such as mineral and silicone oils, flame retardants, corrosion inhibitors , urea and others.

These binder additives and other added agents are usually added in amounts not exceeding 20% by weight of the binder solid. The addition of a hardening catalyst in the binder composition is generally between 0.02 and 2%, based on the solid.

The final composition of the binder

The binder composition described above usually has 50-70% by weight of dry matter. This is especially common if the binder is to be transported. A lower concentration binder has high transport costs and a higher viscosity, which is unfavorable for manipulation.

This is also the normal binder concentration range in storage tanks before use.

In the ready-to-use form, the binder, together with additives, preferably has a concentration of between 5 and 25%.

The viscosity of the binder described above can be adjusted in order to achieve suitable application properties and, in particular, spray properties. This is achieved e.g. by regulating the composition of the binder, the amount of catalyst added, and the amount of water added as solvent.

-7Procedure for the Production of a Mineral Fiber Binder Product of the Invention The aqueous phenolic binder of the present invention may be applied to mineral fibers or mineral fiber products by conventional techniques such as e.g. spray through nozzles, with or without air, spray with rotating discs, soaking, roller application, curtain application, belt application, etc.

Mineral fibers sc (may be any man-made glass fiber (MMVF), glass fiber, ceramic fiber, basalt fiber, slag wool, rock wool and more.

For the production of conventional thermal or acoustic insulation materials, the binder is applied in quantities of between 0.3-10% by weight of the mineral fiber bonded product, between 10 and 30% for HDT (high density) panels and 20-40% for composite binder products, reinforced with mineral fibers.

The catalyst is best added to the binder immediately before entering the metering pumps with a special metering system that allows dosing and homogenization directly in the pipeline, thus preventing the resin from premature hardening and possibly clogging of the pipelines and pumps. The pumps must be made of special material suitable for the physico-chemical properties of the binder.

In general, the binder is applied, usually by spraying, immediately after the mineral melt is bifurcated, and then the coated mineral is formed into a layer in the settling chamber. As the melting mechanism of melamine urea formaldehyde resin is significantly different from that of phenol formaldehyde resin, the correct technological parameters of this segment are essential for smooth production. The temperature in the settling chamber, including the conveyor, must be below the resin initiation temperature, which can be achieved e.g. by cooling with cold air, liquefied gases (CO2), cold water, etc.

The mineral fiber layer thus formed is solidified in a curing chamber where the mineral wool layer is blown with hot air to solidify the binder. Typically, the evasion chamber operates at temperatures of 200 - 400 ° C. Preferably, the escape temperatures range between 225 and 300 ° C. Generally, the dwell time of the escape chambers is 3 min. up to 20 min., depending on e.g. of product density. Since complete crosslinking of the resin is essential for a quality finished product, special care must be taken, for example. adjust the amount of water in the layer in front of the curing chamber, the amount of catalyst added and the other parameters listed above.

-8In addition to conventional hot air curing, other curing methods may be used, e.g. hardening by microwave or infrared radiation. If desired, a layer of mineral wool may also be subjected to pre-curing.

Mineral wool product

Mineral fiber bonding product coming from a curing chamber in the form of e.g. panels, can be cut into the desired format and optionally packaged for transportation. It can also be used as a semi-finished product for the production of molded products and composite materials.

Mineral wool products are, for example, woven and non-woven, felt, panels, blocks, oriented, non-oriented, and other shaped products for use, for example, as thermal or acoustic insulation materials, vibration dampers, building materials, roof reinforcement materials or floor applications, composite articles for technical purposes, as filter material, as a horticultural growth medium, and other applications.

Although the phenol-free aqueous binder according to the present invention is particularly useful for mineral fiber binding, it can also be used as a binder for e.g. hardboard, cellulose fibers, nonwovens, composites, coatings and the like.

-9Results of industrial tests

Comparison of product properties of phenol formaldehyde resin bonded product and melamine urea formaldehyde bonded product

We compared two products, namely DDP (dachdammplatten, roof panels) with a density of 165 kg / m3 and a thickness of 60 mm, and BS (Brandschutz, fire panels) with a density of 130 kg / m3 and a thickness of 50 mm.

DDP 165/60 Phenol-formaldehyde resin Melamine urea formaldehyde resin (0.05%) cat.) binder 3.5% 3.5% emulsion 0.3% 0.3% water repellency 0.08 kg / m ² 0.15 kg / m ² shear strength 38kPa 42 kPa E-module 1400 kPa 2200 kPa decomposition strength (air-conditioning) 9kPa 8,8 kPa proportion of initial strength 0.24 0.21 raising the temp. (flammability) 16 ° C (at 3.8% heat loss) 7 ° C (at 4.3% heat loss)

BS 130/50 phenol-formaldehyde resin Melamine-formaldehyde resin (0.05% Cat.) binder 1.3% 1.3% emulsion 0.2% 0.2% KBV (dT = 140 ° C) 32 min 43 min

The results of the measurements show that the products bound to the melamine urea formaldehyde resin according to the invention are more non-combustible and have greater resistance to heat breakdown and as such are very suitable for fire-fighting products.

Claims (11)

PATENT APPLICATIONS A process for the manufacture of a partially etched water-soluble melamine urea formaldehyde resin as the basis of a mineral fiber binder, characterized in that the condensation and etching are conducted in a one-step process under atmospheric pressure by mixing the melamine (0.5-1.5 mol), urea (0.5-1.5 moles) and formaldehyde (30 -50% aqueous solution, 1.6-2.6 moles per mole of combined amines), and methanol (2-3 moles per mole of amines) set the pH to 8.0 -11 and stir the mixture with vigorous stirring. it is heated to 80 to 100 ° C, with the reaction taking place in the reactor under reflux conditions for 100 to 300 minutes, controlling the hydrophobicity, viscosity and / or refractive index. 2. A process for making a partially etched water-soluble melamine urea formaldehyde resin as a base of mineral fiber binder, characterized in that the condensation and etching are conducted in a one-step process at a pressure of 1-5 bar by mixing the melamine (0.5-1.5 mol) ), urea (0.5-1.5 moles) and formaldehyde (30 - 50% aqueous solution, 1.6-2.6 moles per mole of combined amines), and methanol (2-3 moles per mole of amines) set the pH to 8.5-10 and the reaction leads to temperature range 80 to 120 ° C, in the control of hydrophobicity, viscosity and / or refractive index. A method of manufacturing a mineral fiber binder comprising a resin obtained according to any one of claims 1-2, further comprising a fumigation catalyst and optionally other suitable additives to the binder. Process according to Claim 3, characterized in that substances which release the acidic component, preferably acids, acidic salts of inorganic acids, or adducts of organic acids and amines, preferably formic acid, are used as the catalyst for incubation for the melamine urea formaldehyde binder. hydrochloric acid, nitric acid, ammonium sulfate, ammonium nitrate, ammonium chloride, monoethanolamide of paratoluenesulfonic acid, morpholinium salt of paratoluenesulfonic acid. Process according to claim 4, characterized in that the amount of catalyst in the binder composition is preferably between 0.02 and 2%, based on the solid. Process according to claim 3, characterized in that suitable additives to the binder are silane-based binders, preferably aminopropylsiloxanes, thermal stabilizers, tJV stabilizers, surfactants, fillers such as clay, silicates and magnesium sulfate, pigments, -11 Hydrophobic agents such as mineral and silicone oils, flame retardants, corrosion inhibitors, urea and others. Method according to claim 6, characterized in that the additives to the binder are added in quantities not exceeding 20% by weight of the binder solid. An aqueous mineral fiber binder, characterized in that it is made by the process of claims 1 to 7. 9. A process for the production of a mineral fiber binder product according to claim 8, characterized in that for the production of conventional thermal or acoustic materials the binder is applied in quantities of between 0.3-10% by weight of the mineral fiber bonded product, between 10 and 30% for HDT and 20-40% for mineral fiber-reinforced composite products, the catalyst being added to the binder immediately before entering the dosing pumps by which the binder is sprayed immediately after mineral melt and the temperature in the settling chamber is below the resin initiation temperature, after which the mineral fiber layer thus formed is solidified in the evacuation chamber, where the mineral wool layer is blown with hot air at temperatures of 200-400 ° C. 10. Mineral fiber articles, including mineral fibers in contact with a hardened binder according to claim 8. Mineral fiber articles, characterized in that they are made according to the method of claim 9.