CS256860B1 - Binding mixture on polyurethan base - Google Patents

Abstract

Polyurethane-based bonding compound designed for bonding soft materials and for the treatment of flexible textile fabrics services, the essence of which is polyester polyol, dicarboxylic acid reaction product acids with divalent and polyvalent alcohols, plain and other raw materials necessary for creation and stabilizing the foam.

Description

The invention provides a bonding composition for bonding soft materials, such as textiles, rubber, plastics, which are formed into planar or volumetric panels, but also for the treatment of flexible planar structures such as woven, knitted and nonwoven textile mats and other materials.

Soft materials, both natural and synthetic, are processed on a large scale for a wide range of applications. Of course, their processing also generates technological waste, usually in a fairly considerable mass, in the case of lightweight materials and volume. This causes problems in the disposal of this waste and so there are known, but still sought, methods of effective recovery. In addition to the classical methods, such as, for example, flaking and re-use, regeneration of rubber and also re-use, heat treatment of thermoplastics, other ways of their recovery are sought. Thus, a number of technologies are encountered where the soft and / or soft cellular materials, after their pretreatment, are bonded to obtain sheet or volume panels.

As binders, solutions, dispersions or emulsions, pastes, solid binders in the form of powders, fibers, threads and the like can be used. However, dispersions or emulsions of macromolecular substances or emulsions remain the most common forms of binders. mixtures thereof. However, these bonding compositions form a predominantly solid bond between the individual particles, especially at a higher dry matter content of the bonding composition, even when dispersing or emulsifying elastomeric substances. Therefore, it is often necessary to choose a compromise between the binder mixture content and the stiffness of the final product, but certainly also a compromise between tensile strength, ductility and other physico-mechanical values. However, such products can have only a limited range of applications. Therefore, in some cases it is advisable to use bonding compositions which, by chemical or mechanical means, produce lightweight compositions which not only ensure the bonding of individual particles but also fill the space between the particles and thereby ensure homogeneity of the entire system and give it the desired softness and elasticity.

Substantially the same problem arises in the treatment of flexible planar formations, mostly non-woven fabrics, where the bonding or impregnation has the task of forming a compact whole, which means performing a mechanical interconnection of the textile elements. It is therefore necessary that the mechanical and chemical properties of the binders correspond to those of textile fibers. Dispersions or emulsions of macromolecular substances are also most commonly used for bonding, and the issue is similar to that briefly outlined in the previous section.

In summary, the effective application of the binder mixture depends not only on the actual composition and structure of the final product, but also on the derived mechanical and chemical properties and the chosen technology. The bonding composition must produce sufficient mechanical strength, sufficient adhesion to the bonded material, chemical stability under the conditions under which the product is used, adequate spreading capacity, satisfying technological properties. It has already been stated that the bonding of dispersions or emulsions of a macromolecular substance causes some problems with the formation of hard bonds and not a completely effective and uniform distribution of the binder. It has been noted that in some cases bonding with mixtures which allow the formation of foam is recommended. The foamed binder composition has a larger contact area, which results in a more even bonding of the binder and a greater number of contact areas as well as other positive properties. These aspects can significantly affect the better use of the binder as well as the increased utility value of the product and thus combine the technical effect with the economic effect.

In principle there are 3 known foaming methods: mechanical, physical and chemical. Depending on the process, the waste is comminuted into smaller particles, mixed thoroughly with the binder mixture, and is usually formed into the desired shape by pressure. After the sieving and other necessary technological operations are completed, the working process is completed. The flexible planar formations are treated in a similar way.

The present invention provides a polyurethane-based binder composition which is foamed by a chemical or chemical-physical process, which is distinguished by its ease of processing and the particularly favorable properties which give the product a high quality level.

Known polyurethane-based bonding compositions are usually designed using polyether polyol as two-component or one-component (prepolymer) systems. The binder composition of the invention is based on the use of polyester polyol. It is generally a product having a molecular weight of 800 to 5,000, made on the basis of dicarboxylic acids and / or its anhydrides with divalent or polyhydric alcohols, e.g. ethylene glycol, 1,3 butylene glycol, 1,3 propylene glycol, neopentyl glycol, 1,6 hexanediol, 1,4-butanediol, - trimethylolpropane, glycerine and a number of other compounds. However, for economic reasons, adipic acid, phthalic anhydride and maleic anhydride are used, and ethylene glycol, propylene glycol, butanediol, hexanediol are used from the alcohols.

As is known in urethane chemistry, these hydroxyl-containing polyester polyols react with diisocyanates, usually in the presence of catalysts, activators, blowing agents, water, etc. to form carbon dioxide and form a urethane structure. As diisocyanates for this reaction, for example, 4,4 diphenylmethane diisocyanate, 2,4 and 2,6 toluylene diisocyanate, 1,6 hexane diisocyanate and the like can be used. A detailed description of the polyurethane foam technology is given, for example, in the book in Becker-Polyurethane (VEB Fachbuchverlag, Leipzig 1973).

The binder mixture is designed so that the basic ratio of polyester polyol to diisocyanate is given by an isocyanate index in the range of 200 to 400. For foaming, a combination of a chemical and a physical method is chosen, for chemical foaming a water is selected and physical methylene chloride or monofluorotrichloromethane. This choice is also important in terms of adjusting the viscosity of the entire composition, but especially its polyol portion. The viscosity of the polyester polyol is in the range of 600 to 1500 mPas at 75 [deg.] C. and the reduction in the viscosity of the whole mixture has a very favorable effect on the process. One of the most important parameters is the choice and dosing of the crosslinking catalyst system, since it can be assumed that even under different technological and production conditions, the reaction times of foam formation must be within these ranges. sieving 400 to 800 s. With regard to production conditions and working environment, a tertiary amine having a minimum odor can be used as a crosslinking catalyst. The selection and dosing of surfactants is also related to the requirement for a relatively long foaming time. Depending on the machinery used, a further auxiliary component, which is an organic monomeric or polymeric diluent, which can further influence the viscosity of the entire mixture, remains at the discretion.

From the foregoing, the subject matter of the invention is a binder mixture consisting of 100 wt. d. polyester polyol having a molecular weight of 800 to 5,000, a hydroxyl number of 37 to 115, an acid number of not more than 2 mg KOH / g, a viscosity of 600 to 1500 mPas at 75 ° C, 0.1 to 1.0 wt. d. medium reactivity tertiary amine, 0.5 to 1.5 wt. d. a polysiloxane surfactant and / or 0.7 to 9.0 wt. d. surfactant org. 0.5 to 3.0 wt. d. water and / or 3.0 to 20.0 wt. d, physical blowing agents, which are the most available methylene chloride and monofluorotrichloromethane at the dosage of diisocyanate, most commonly toluylene diisocyanate having an index value of 200 to 400.

The binder mixture thus conceived is then as follows. A polyol composition A is prepared consisting of corresponding amounts of polyester polyol, surfactant, water, tertiary amine, blowing agent, and the like. other ingredients and an isocyanate component B consisting of the selected diisocyanate or mixtures thereof. By means of a special low-pressure or high-pressure machine, both components are mixed in the prescribed ratio, given by the isocyanate index, and dosed either into the mixing drum (for the treatment of flat flexible formations). A detailed description of the dispensing machines as well as further processing conditions is given in the literature and in the company brochures.

Example 1

A bonding composition of 100% by weight is applied to a nonwoven web of 6.5 mm thickness and 950 g / m 2 consisting of 50% natural and 50% synthetic fibers. d. polyester polyol (molecular weight 2700, hydroxyl # 50 mg KOH / g), prepared by the reaction of an acid;

256860 4 adipic acid, phthalic anhydride and monoethylene glycol, 4.0 wt. d. surfactant org. fabrics designation Dispergiemittel EM, 0.5 wt. d. triethylenediamine, 1.0 wt. d. water,

5.0 wt. d. monofluorotrichloromethane at a toluene diisocyanate feed rate of 250.

The bonding composition begins to react and forms foam in a time period defined by the so-called reaction times - beginning of foaming 16 s, foaming time 325 s, crosslinking time 720 s. In this time period, the bonding composition is applied to the nonwoven sheet and to get into its structure. At the beginning of the foaming, the foam interconnects the entire volume of the nonwoven sheet during free foaming, or while covering the bottom and top surfaces of the nonwoven sheet with separation plates. To speed up the crosslinking time, the nonwoven is subjected to thermal radiation, which adjusts its surface temperature to 50 ° C. The resulting product with a density of 120 kg / m pevnost has a tensile strength according to ČSN 64 5431 of 0.23 MPa and an elongation according to ČSN 64 5431 of 80%.

Example 2

The soft polyurethane foam, crushed into uniform, irregular pieces with an average size of 0.5 to 1.5 cm, is wetted and mixed with a binder mixture consisting of 100 wt. d. polyester polyol (mol. wt. 2700, hydroxyl number 50 mg KOH / g), prepared by the reaction of phthalic acid, diethylene glycol and trimethylolpropane, 2.0 wt. d. polysiloxane surfactants commer. L-540, 0.5 wt. d. tertiary amine ref. N-methylmorpholine, 0.5 wt. d. water, 10.0 wt. d. methylene chloride at a toluene diisocyanate feed rate of 250.

The composition is filled into a sealed mold prior to foaming with the binder and compressed to a volume corresponding to a predetermined bulk density of the article. The crosslinking reaction of the binder mixture is accelerated by placing the mold in an oven and subjecting it to 130 ° C for 25 minutes. All working operations are combined with reaction times of the bonding mixture, which are - start of foam 20 s, foam time 275 s, cross-link time 600 s. The resulting product has the following values at tensile weight 100 kg / m - tensile strength, ductility according to ČSN 64 5431 0,15 MPa and 100%, permanent deformation acc. ČSN 64 5442 7.5%, compression resistance according to ČSN 64 5441 8.2 kPa.

Claims (1)

SUBJECT OF THE INVENTION Polyurethane-based bonding composition for bonding soft materials and for treating flexible flat textile structures, characterized in that it contains 100 wt. d. polyester polyol having a specific molecular weight of 800 to 5,000, a hydroxyl value of 37 to 115 mg KOH / g, a viscosity of 600 to 1,500 mPas at 75 ° C, the reaction product of dicarboxylic acids and / or their anhydrides with divalent or polyhydric alcohols; 1 to 1.0 wt. d. a tertiary amine, 0.5 to 2.5 wt. d. a polysiloxane surfactant and / or 0.5 to 8.0 wt. d. surfactant organic, 0.5 to 3.0 wt. d. water and / or 3.0 to 20.0 wt. d. Physical blowing agents, such as methylene chloride and monofluorotrichloromethane, and diisocyanate, most commonly toluylene diisocyanate having an isocyanate index value of 200 to 400.