FR2976584A1 - SIZING COMPOSITION FOR MINERAL WOOL BASED ON SALT OF LIGNOSULPHONIC ACID AND OLIGOSACCHARIDE, AND INSULATING PRODUCTS OBTAINED - Google Patents

Abstract

The present invention relates to a sizing composition for insulating products based on mineral wool, in particular glass or rock, which comprises - at least one lignosulfonic acid salt, - at least one oligosaccharide, and - a catalyst crosslinking. It also relates to the insulating products based on mineral fibers obtained and their manufacturing process.

Description

SIEBING COMPOSITION FOR MINERAL WOOL BASED ON SALT OF LIGNOSULPHONIC ACID AND OLIGOSACCHARIDE, AND INSULATING PRODUCTS OBTAINED

The present invention relates to the field of insulation, thermal and / or acoustic products, based on mineral wool, in particular glass or rock, and an organic binder free of formaldehyde. The invention relates more particularly to a sizing composition capable of crosslinking to form said organic binder which contains at least one lignosulfonic acid salt, at least one oligosaccharide and at least one crosslinking catalyst of the abovementioned compounds, as well as the products resulting insulation. The manufacture of insulating products based on mineral wool generally comprises a step of manufacturing the wool itself, which can be carried out by various methods, for example according to the known technique of internal or external centrifugal fiber drawing. Centrifugation consists in introducing the molten mineral material (glass or rock) into a centrifugal device comprising a multitude of small orifices, the material being projected towards the peripheral wall of the device under the action of the centrifugal force and escaping under the form of filaments. At the exit of the centrifugal device, the filaments are stretched and driven to a receiving member by a gaseous stream of high temperature and velocity to form a web of fibers (or mineral wool). To ensure the assembly of the fibers together and to allow the web to have cohesion, a sizing composition is sprayed onto the fibers in the path from the outlet of the centrifugal device to the receiving member. a thermosetting resin. The layer of fibers coated with the sizing is subjected to a heat treatment, at a temperature generally greater than 100 ° C., in order to effect the polycondensation of the resin and thus to obtain a thermal and / or acoustic insulation product having specific properties, including dimensional stability, tensile strength, thickness recovery after compression and a homogeneous color. The sizing composition to be sprayed on the mineral wool is generally in the form of an aqueous solution containing the thermosetting resin and additives such as a resin crosslinking catalyst, an adhesion promoter silane and a mineral oil. anti-dust, ... The sizing composition is most often applied to the fibers by spraying.

The properties of the sizing composition depend to a large extent on the characteristics of the resin. From the point of view of application, it is necessary that the sizing composition has good sprayability and can be deposited on the surface of the fibers in order to bind them effectively.

The resin must be stable for a given period of time before being used to form the sizing composition, which composition is generally prepared at the time of use by mixing the resin and additives mentioned above. In terms of regulation, it is necessary for the resin to be considered as non-polluting, that is to say that it contains - and that it generates during the sizing step or later - as little as possible of compounds which may be harmful to human health or the environment. The thermosetting resins most commonly used are phenolic resins belonging to the family of resoles. In addition to their good ability to crosslink in the aforementioned thermal conditions, these resins are soluble in water, have a good affinity for mineral fibers, especially glass, and are relatively inexpensive. Resols are generally obtained by reaction of a phenol and an aldehyde under basic conditions, a proportion of which of these unreacted compounds is found in the final resin. The most used aldehyde is formaldehyde, the presence of which in the form of free formaldehyde is not desired because of its proven harmful effects. As environmental protection regulations become more stringent, insulation manufacturers have to look for solutions to further reduce unwanted emission levels, particularly of formaldehyde, either at the level of manufacture of insulation products or their use. Solutions for replacing the resols in the sizing compositions are known and are based on the use of a carboxylic acid polymer, in particular acrylic acid, and a hydroxylated compound. In US 5,340,868, the sizing comprises a polycarboxylic polymer, an R-hydroxylamide and an at least trifunctional monomeric carboxylic acid.

Sizing compositions comprising a polycarboxylic polymer, a polyol and a catalyst, which catalyst is a phosphorus-containing catalyst (US 5,318,990, US 5,661,213, US 6331,350, US 2003/0008978), are also known. fluoroborate (US 5,977,232) or cyanamide, dicyanamide or cyanoguanidine (US 5,932,689).

Sizing compositions comprising an alkanolamine containing at least two hydroxyl groups and a polycarboxylic polymer (US Pat. No. 6,071,994, US 6,099,773, US 6,146,746, US 2002/0091185) combined with a copolymer (US 6,299) are also known. 936). Sizing compositions based on a polycarboxylic polymer and a polyol may additionally contain a cationic, amphoteric or nonionic surfactant (US 2002/0188055) or a silane coupling agent (US 2004/0002567). It has also been proposed to replace all or part of the hydroxylated compound with a saccharide.

In US 2005/0215153, there is described a sizing formed from a pre-binder containing a carboxylic acid polymer and a polyol, and a dextrin as a co-binder. Furthermore, there is known an adhesive composition based on thermally crosslinkable polysaccharides which can be used as a sizing for mineral wool (US 5,895,804). The composition comprises a polycarboxylic polymer having at least two carboxylic acid functional groups and a molecular weight of at least 1000, and a polysaccharide having a molecular weight of at least 10000. Also known is a formaldehyde-free aqueous sizing composition which comprises a Maillard reaction product, in particular combining a reducing sugar, a carboxylic acid and ammonia (WO 2007/014236). In WO 2009/019232 and WO 2009/019235, it is proposed to substitute the carboxylic acid with an acid precursor derived from an inorganic salt, especially an ammonium salt which has the additional advantage of being able to replace all or part of the ammonia. In WO 2009/080938, the sizing composition for mineral wool comprises a monosaccharide and / or a polysaccharide and a polycarboxylic organic acid with a molar mass of less than 1000, optionally in combination with a catalyst for adjusting the crosslinking start temperature. . Furthermore, it is proposed in WO 2011/045531 a sizing composition for mineral wool based on a reducing sugar and a metal salt of inorganic acid selected from alkali metal salts, alkaline earth metal, transition metal or inorganic acid poor metal. The present invention aims to provide an alternative to sizing compositions for insulating products based on mineral wool not containing formaldehyde.

This object is achieved according to the invention by the sizing composition for insulating products based on mineral wool, in particular glass or rock, which comprises - at least one lignosulfonic acid salt, - at least one oligosaccharide, and a crosslinking catalyst. The lignosulfonic acid salt is generally a complex mixture of several lignosulfonic acids in salified form, commonly referred to as "lignosulfonate". Lignosulphonates are by-products from the treatment of wood for the manufacture of paper pulp using the "sulphite" process. This process, which uses a sulfite or a bisulfite, allows, depending on the nature of the counterion used, to obtain lignosulfonates of sodium, calcium, potassium, magnesium or ammonium. The preferred lignosulfonic acid salt according to the invention is ammonium lignosulfonate.

The lignosulfonic acid salts also make it possible to give the binder good fire resistance. By "oligosaccharide" is meant any type of saccharide, reducing or non-reducing, containing at most 10 units of ose. The oligosaccharide is chosen from monosaccharides containing 3 to 8 carbon atoms, preferably the aldoses and advantageously the aldoses containing 5 to 7 carbon atoms. The particularly preferred aldoses are natural aldoses (belonging to the D series), in particular hexoses.

By way of examples, mention may be made of monosaccharides, preferably containing 5 to 7 carbon atoms, in particular glucose, mannose, galactose and fructose; disaccharides such as sucrose, maltose, cellobiose, trehalose, lactose, gentobiose and melibiose; trisaccharides such as raffinose and gentianose; tetrasaccharides such as stachyose; and fructose polymers, especially fructans and in particular inulin. Advantageously, the oligosaccharide is glucose, fructose and sucrose, preferably sucrose. In the binder, the lignosulfonic acid salt preferably represents 10 to 70% of the weight of the mixture consisting of the lignosulfonic acid salt and the oligosaccharide, advantageously 10 to 60% and better still 10 to 50%. The function of the crosslinking catalyst is to accelerate the formation of ester bonds between the lignosulfonic acid salt and the oligosaccharide under the effect of heat, which leads to obtaining a polymer network in the final binder. Said polymeric network makes it possible to establish bonds at the junction points of the fibers in the mineral wool. The catalyst also makes it possible to adjust the starting temperature of the crosslinking of the binder. The crosslinking catalyst is chosen from compounds containing phosphorus and sulphates.

By way of examples, mention may be made of alkali metal hypophosphite salts, alkali metal phosphites, alkali metal polyphosphates, alkali metal hydrogenphosphates, phosphoric acids and alkylphosphonic acids, in which the alkali metal is preferably sodium or potassium; ammonium phosphates, especially diammonium phosphate; and ammonium sulphate. Particularly preferred are sodium hypophosphite, diammonium phosphate and ammonium sulfate. In general, the amount of crosslinking catalyst in the binder represents 2 to 25% by weight of the lignosulfonic acid salt and the oligosaccharide, preferably 3 to 20%, advantageously 3 to 15% and better still 5 to 10% . The sizing composition according to the invention may furthermore comprise the conventional additives hereafter in the following proportions calculated on the basis of 100 parts by weight of lignosulfonic acid salt and of oligosaccharide: 0 to 2 parts by weight silane, in particular an aminosilane, 0 to 20 parts of oil, preferably 4 to 15 parts, 0 to 30 parts of urea and / or of glycerol, preferably 0 to 20 parts, 0 to 5 parts of a silicone. The role of the additives is known and briefly recalled: the silane is a coupling agent between the fibers and the binder, and also acts as an anti-aging agent; the oils are anti-dust and hydrophobic agents; urea and glycerol play the role of plasticizers and prevent the pregelling of the sizing composition; silicone is a hydrophobic agent whose function is to reduce the absorption of water by the insulation product. The sizing composition is intended to be applied to mineral fibers, in particular glass or rock fibers.

In a conventional manner, the sizing composition is projected onto the mineral fibers at the outlet of the centrifugal device and before they are collected on the receiving member in the form of a sheet of fibers which is then treated at a temperature permitting the crosslinking of the sizing and the formation of an infusible binder. The crosslinking of the sizing according to the invention is carried out at a temperature comparable to that of a conventional formophenolic resin, at a temperature greater than or equal to 110 ° C., preferably greater than or equal to 130 °, advantageously greater than or equal to 140 ° C and more preferably at most equal to 300 ° C. The acoustic and / or thermal insulation products obtained from these sized fibers are also an object of the present invention. These products are generally in the form of a mattress or felt of mineral wool, glass or rock, or a veil of mineral fibers, also glass or rock, intended in particular to form a coating surface of said mattress or felt. The following examples illustrate the invention without limiting it. In these examples, we measure: the thickness of the product after manufacture and after a variable duration under compression with a compression ratio (defined as the ratio of the nominal thickness to the thickness under compression) equal to 8. The measurement of the thickness makes it possible to evaluate the good dimensional strength of the product, the tensile strength according to ASTM C 686-71T on a stamped sample in the insulating product. The sample has the shape of a torus 122 mm long, 46 mm wide, a radius of curvature of the cutout of the outer edge equal to 38 mm and a radius of curvature of the cutout of the inner edge equal to 12, 5 mm.

The sample is placed between two cylindrical chucks of a test machine, one of which is movable and moves at a constant speed. The tensile strength F (in Newton) of the sample is measured and the tensile strength RT defined by the ratio of the breaking force F to the mass of the sample is calculated.

The tensile strength is measured after manufacture (initial tensile strength) and after accelerated aging in an autoclave at a temperature of 105 ° C at 100% relative humidity for 15 minutes (RT15). EXAMPLES 1 TO 4 Sizing compositions comprising the constituents appearing in Table 1 (in parts by weight) are prepared. The sizing compositions are used to form insulation products based on mineral wool. Glass wool is produced by the technique of internal centrifugation in which the molten glass composition is transformed into fibers by means of a tool called a centrifugation plate: the plate is rotated about its axis of symmetry. arranged vertically, the composition is ejected through the orifices under the effect of the centrifugal force and the material escaping from the orifices is drawn into fibers with the assistance of a stream of drawing gas. Conventionally, a sizing spray crown is disposed below the fiberizing plate so as to evenly distribute the sizing composition on the newly formed glass wool. The mineral wool thus glued is collected on a belt conveyor equipped with internal suction boxes which hold the mineral wool in the form of a felt on the surface of the conveyor. The felt is then cut and placed in an oven maintained at 210 or 230 ° C where the components of the sizing polymerize to form a binder. An insulation product is manufactured under the same conditions by means of a reference sizing composition (Reference 1) containing (in parts by weight): 60 parts by weight of a phenol-formaldehyde resole, 40 parts of urea, 0.5 parts of silane, 3 parts of ammonium sulphate and 6 parts of a 20% by weight solution of aqueous ammonia. The resole is obtained by reacting phenol and formaldehyde, in a formaldehyde / phenol molar ratio of 3.2, in the presence of a catalyst (NaOH, 6% by weight relative to phenol), the resole being neutralized at pH 7, 3 with sulfamic acid. The insulation product obtained has a nominal density equal to 10.6 kg / m 3 and a nominal thickness equal to 80 mm. The results are given in Table 1. EXAMPLES 5 TO 12 Sizing compositions comprising the constituents shown in Table 2 (in parts by weight) are prepared. Isolation products are manufactured under the conditions of Examples 1 to 4. A reference sizing composition different from the previous one (Reference 2) is used which contains 80 parts by weight of a phenolformaldehyde-ethanolamine resin (Example 1). of WO 2008/043960) and 20 parts by weight of urea.

The results are given in Table 2, Table 1 Ex.

1 Ex.

2 Ex.

3 Ex.

4 Ref.

1 Sizing composition 50 50 50 50 - Ammonium lignosulfonate (1) Oligosaccharide 50 50 50 - - Glucose syrup (2) Glucose / fructose mixture (3) - - - - Diammonium phosphate - - 5 - - aminopropyltriethoxysilane 1 1 1 1 0.5 Oven temperature (° C) 210 230 230 230 210 Properties of the product n. d. 124 143 n. d.

152 Thickness (mm) after 24 hours after 30 days n. d. 110 118 n. d.

142 Tensile strength (N / g) 1.8 2.1 2.9 2.7 4.1 initial after aging 1.8 2.2 2.9 2.6 3.8 Loss on fire (%) 6 6 6 6 4.7 (1) Arbo T5 marketed by Tembec (2) 74/968 marketed by Roquette (weight content of glucose 5: 96%) (3) ISO-glucose C * TruSweet 01750 marketed by the company Cargill n. d. : not determined Table 2 Ex.5 Ex.6 Ex.7 Ex.8 Ex.9 Ex.10 Ex.11 Ex.12 Ref.2 Sizing composition 50 50 50 50 50 50 50 50 - Ammonium lignosulfonate ( ') Oligosaccharide 50 50 50 - - - - - - Glucose syrup (2) Inverted sugar ~ 4 ~ - - - 50 - - - - - Sucrose - - - - 50 50 50 50 - Catalyst 5 - - 5 5 10 - - - Diammonium phosphate Sodium hypophosphite - 5 - - - - 5 - - Ammonium sulphate - - 5 - - - - 5 - y-aminopropyltriethoxysilane 0,5 0,5 0,5 0,5 0,5 0,5 0.5 0.5 0.5 Oven temperature (° C) 230 230 230 230 230 230 230 230 210 Properties of the product 2,3 2,2 2,5 2,5 3,0 2,7 2, 8 3.3 3.9 Initial tensile strength (N / g) after aging 2.4 2.2 2.7 2.6 3.1 2.8 2.8 3.5 3.9 Loss on fire (% ) 6 6 6 6 6 6 6 6 4.7 (1) Arbo T5 marketed by Tembec (2) 74/968 marketed by Roquette (weight content of glucose: 96% by weight) (4) SI9571 marketed by the company Tereos Sucre; (weight content: glucose: 47.5%, fructose: 47.5%, sucrose: 5%)

Claims (12)

REVENDICATIONS1. Sizing composition for insulating products based on mineral wool, especially rock or glass, characterized in that it comprises - at least one lignosulfonic acid salt, - at least one oligosaccharide, and - at least one crosslinking catalyst. 2. Composition according to Claim 1, characterized in that the lignosulfonic acid salt is chosen from lignosulfonates of sodium, calcium, potassium, magnesium or ammonium, preferably ammonium. 3. Composition according to claim 1 or 2, characterized in that the oligosaccharide contains at most 10 saccharide units. 15 4. Composition according to claim 3, characterized in that the oligosaccharide is a monosaccharide, preferably containing 5 to 7 carbon atoms, a disaccharide, a trisaccharide, a tetrasaccharide or a fructose polymer such as a fructan. 5. Composition according to claim 4, characterized in that the oligosaccharide is chosen from glucose, mannose, galactose, fructose, sucrose, maltose, cellobiose, trehalose, lactose, gentobiose, melibiose, raffinose, gentianose, stachyose and inulin. 6. Composition according to one of claims 1 to 5, characterized in that the lignosulfonic acid salt represents 10 to 70 of the weight of the mixture consisting of the lignosulfonic acid salt and the oligosaccharide, preferably 10 to 60 %, and advantageously 10 to 50%. 7. Composition according to one of claims 1 to 6, characterized in that the crosslinking catalyst is an alkali metal hypophosphite salt, an alkali metal phosphite, an alkali metal polyphosphate, an alkali metal hydrogen phosphate, phosphoric acid or alkylphosphonic acid, ammonium phoshate and ammonium sulfate. 8. Composition according to claim 7, characterized in that the alkali metal of the crosslinking catalyst is sodium or potassium. 13 9. Composition according to claim 7 or 8, characterized in that the crosslinking catalyst is sodium hypophosphite, diammonium phosphate or ammonium sulfate. 10. Composition according to one of claims 1 to 9, characterized in that the amount of crosslinking catalyst is 2 to 25% by weight of the lignosulfonic acid salt and the oligosaccharide, preferably 3 to 20%, advantageously 3 to 15% and more preferably 5 to 10%. 11. Composition according to one of claims 1 to 10, characterized in that it further comprises the conventional additives hereinafter in the following proportions calculated on the basis of 100 parts by weight of lignosulfonic acid salt and of oligosaccharide: 0 to 2 parts of silane, in particular an aminosilane, 0 to 20 parts of oil, preferably 4 to 15 parts, 0 to 30 parts of urea and / or glycerol, preferably 0 to 20 parts parts, - 0 to 5 parts of a silicone. 12. Acoustic and / or thermal insulation product based on mineral wool, in particular glass or rock, glued with the aid of the sizing composition according to one of claims 1 to 11.20