RO120414B1 - Process for making polyurethane backed carpets made of polyurethanic latex formulations - Google Patents

Abstract

The invention relates to a polyurethane-backed carpet having a backing prepared by the application of an aqueous dispersion of polyurethane or polyurethane-forming material to the back of a carpet substrate. The invention eliminates the need to prepare a polyurethane backing from its monomeric components at the carpet manufacturing site.The claimed polyurethane-backed carpet can be efficiently prepared by a continuous process.

Description

The invention relates to carpets on polyurethane support, in particular to carpets on polyurethane support and to a process used to manufacture them from polyurethane latex compositions.

For the manufacture of carpet with brushes a second adhesive support is required to fix the carpet brushes to the first carpet support. Carpets with polyurethane support can exhibit superior performance in terms of catching pears, cough exfoliation, resistance to loss of properties in the presence of water and water resistance. Carpets and other substrates having layers of polyurethane foam bonded as supports are described, for example, in U.S. Patent Nos. 3755212; 3772224; 3821130; 3862879; 4022941; 4171395; 4278482; 4286003; 4296159; 4405393; 4483894; 4512831; 4515646; 4595436; 4611044; 4657790; 4696849; 4853054; 4853280 and 5104693. Carpets with polyurethane supports tend to be more expensive than carpets that incorporate other types of supports, due to the costs of raw materials when producing polyurethane support. For this reason, polyurethanes are usually used on high quality carpets and are not used on low and intermediate quality carpets.

Publication EP-A-0347206 presents a method of attaching the substrate support layer to the carpet fabrication. Documents DE-U-9212981 and DE-U9309105 also refer to a process for manufacturing a carpet on a support. None of these documents exclude the use of an organic solvent.

Current practice in the carpet manufacturing industry requires that the polyurethane substrates for the carpets be manufactured from an isocyanate formulation (part A formulation) and a polyol formulation (part B formulation) at the polyurethane manufacturing site. This is sometimes known as A + B chemistry. The preparation of a polyurethane by A + B chemistry can lead to an unexpected loss of production and inefficiency, due to the problems that may arise when performing the reaction at the manufacturing site.

Styrene-butadiene (SB) latex is well known. SB latex for use on carpets is described, for example, in P. L. Fitzgerald, Integral Latex Foam Carpet Cushioning, J. Coat. Fab. 1977, You. 7 (pp. 107-120); and in R. P. Brentin, Latex Coating Systems for Carpet Backing, J. Coat. Fab. 1982, you. 12 (pp. 82-91). SB latex is widely used as carpet support layers. SB latex can result in a good bonding of the brushes, with a relatively high degree of rigidity, at a relatively low cost. SB latexes can also result in relatively low rigidity, with the decrease of pearl binding properties at relatively low investment cost. SB latexes can also cause flexibility in production costs depending on the ability to include low to high concentrations of filler material in a low viscosity latex. However, SB latex with filler material cannot meet the rigorous standards set for intermediate quality carpets. In addition, current technology may require latex stability for storage for up to one year. For this reason, SB latex containing solids greater than 55% are not usually commercially available SB latex, as such latexes are not stable for storage.

Polyurethane / urea (PU) latexes are known and are used, for example, as coatings for finishing wood, glass fibers, textiles, adhesives and surface films and primers. Surface autofilms, food packaging adhesives and textiles primarily use aliphatic isocyanates. Wood finishing and films mainly use aromatic isocyanates. PU latexes can be prepared by polymerizing reactants useful in the preparation of polyurethanes in an organic solvent, such as isocyanates and polyols, for example, followed by dispersion of the resulting solution in water and, optionally, followed by solvent removal. PU latexes can be prepared by various processes, including, of

RO 120414 Β1, for example, those disclosed in the patents: US 485766565; 4742095; 879 322; 3437624; 1

5037864; 5221710; 4237264 and 4092286. Eliminating the use of volatile organic solvents in this process may be desirable both in terms of cost and from the perspective of environmental protection.

The problem that the invention aims to solve is that the manufacture of carpets on polyurethane substrate should take place according to a process in which a high performance polyurethane support can be applied to any carpet, of any quality, in a cost process. 7 efficiently. It would also be desirable to eliminate the need to prepare polyurethane support for carpets using A + B chemistry in the carpet manufacturing site. In addition, it would be desirable to prepare a polyurethane carpet support by a continuous process, in which a polyurethane latex can be applied to a carpet, without the additional step of removing the volatile organic solvent.

This problem is solved, according to the invention, by a process for making a carpet on the substrate consisting of the following steps: (1) dispersing a polyurethane prepolymer in water, to obtain an aqueous dispersion of the prepolymer; (2) applying aqueous dispersion 15 on the back of the carpet substrate; (3) removing the water from the aqueous dispersion to obtain a carpet on the support. 17

The invention has the following advantages:

- allows the manufacture of high quality carpets on polyurethane support; 19

- Reduces the manufacturing costs of the carpets on polyurethane support, by making the support in place of the carpet manufacture; 21

- carries out a continuous process of carpet production.

The carpet according to the invention contains a polyurethane carpet support which is obtained by applying a latex polyurethane composition to the back of the carpet substrate. In the present invention, the polyurethane may be a polyurethane compound, a polyurethane compound or a mixture thereof. Polyurethanes can be obtained by the reaction between a polyol and a polyisocyanate. Polyureas can be obtained by the reaction between primary amines and polyisocyanates. A polyurethane or 27 a polyurea may contain both urea and a polyurethane function, depending on what is included in part A or part B of the formulas, in any combination thereof. For the purposes of the present application, no distinction will be made between polymeric materials. The term polyurethane will be used generically to describe either or both polyurethane polymers and polyurethane polymers. Use as in the present invention, the terms latex and aqueous dispersion are used instead of each other to describe the same material. A PU latex composition useful in practice in the present invention includes water and either: a polyurethane, a mixture capable of forming a polyurethane, or a mixture of both. A PU latex, described hereinafter, 35 may optionally include: chain extensors, surfactants, fillers, dispersants, stabilizing foams, thickening agents, flame retardants, or a combination of 37 other optional materials that may be used in the formulas. polyurethane.

According to the practice of the present invention, a PU latex is an aqueous dispersion of: 39 polyurethane, polyurethane forming materials or a combination thereof. The polyurethane forming materials used in the present invention are materials that are capable of forming 41 polyurethane polymers. Polyurethane forming materials include, for example, polymeric prepolymers. The prepolymers useful in the practice of the present invention are prepared by the reaction between 43 active hydrogen compounds and any excess isocyanate relative to the active hydrogen material. The isocyanate function can be present in any amount from 0.2% by weight 45 to 40% by weight. A suitable prepolymer can have a molecular weight in the range of 100 to 10,000. The prepolymers useful in the practice of the present invention should be substantially liquid under any dispersion conditions.

RO 120414 Β1

Active hydrogen compounds can be described as compounds having functional groups containing at least one hydrogen atom directly linked to any electronegative atom such as nitrogen, oxygen or sulfur. Suitable active hydrogen compounds may be polyols with a molecular weight of less than 6 000.

Other latexes can be used in combination with the polyurethane latexes of the present invention to prepare a carpet support according to the invention. Latexes suitable for mixing with polyurethane latexes of the invention include: styrene-butadiene latex, styrene-butadiene-vinylidene latex, alkyl styrene-latex or acrylic latex; other compounds and their mixtures.

The present invention optionally includes a chain extender. A chain extender is used to build the molecular weight of the polyurethane prepolymer by the reaction between the chain extension and the isocyanate function in polyurethane prepolymers, i.e. the chain extends the polyurethane prepolymer. A suitable chain extender is usually a compound containing an equivalent weight of active hydrogen having 2 or more groups of active hydrogen in the molecule. Groups containing active hydrogen may be hydroxyl, mercaptil, or amino groups. An amine chain extension can be blocked, encapsulated, or its reactivity may be reduced in another way. Other materials, in particular water, may work to extend the length of the chain and are also chain extensions for the purposes of the present invention. Polyamines are preferred as chain extensions. It is particularly preferred that the chain extender be selected from the group consisting of polymers terminated with amino groups such as, for example, Jeffamine D-400 from the Huntsman Chemical Company, amino ethyl piperazine, 2-methyl piperazine, 1.5-. diamino-3-methyl-pentane, isophorine diamine, ethylene diamine, diethylene triamine, triethylene tetramine, triethylene pentamine, ethanol amine, lysine in all stereoisomeric forms and its salts, hexane diamine, hydrazine and piperazine. In the practice of the present invention, the chain extension is often used as a solution of the chain extension in water.

In the preparation of the polyurethane support of the present invention small quantities of chain extension may be advantageously used. In general, the chain extender is used at a level sufficient to react with the isocyanate function present in the prepolymer in a percentage from zero (0) to 100, based on an isocyanate equivalent which reacts with an equivalent chain extension. It may be desirable, under certain conditions, to allow water to act as a chain extender and to react with one or more isocyanate functions present. A catalyst may be optionally used to promote the reaction between the chain extender and the isocyanate.

Suitable catalysts for use in the present invention include tertiary amines, organometallic compounds, such as compounds and mixtures thereof. For example, suitable catalysts include iso-n-butyl ester of mercaptoacetic acid tin tin, dimethylstanyl dilaurate, dibutylthanium dilaurate, dibutylthansulfur sulfur, tin octoate, lead octoate, ferric acetylacetonate, bismuth carboxylate, triethylenediamine, N-methylmetiamine and their mixtures. An amount of catalyst is advantageously used so that a relatively rapid treatment to the state of adhesion is obtained. If an organometallic catalyst is used, such treatment can be obtained using from 0.01 to 0.5 parts per 100 parts by weight of the polyurethane-forming composition. If a tertiary amine catalyst is used, the catalyst preferably determines a treatment using 0.01 to 3 parts by weight of the tertiary amine catalyst per 100 parts of the polyurethane-forming composition. Both the amine type catalyst and the organometallic catalyst can be used in combination.

RO 120414 Β1

The invention optionally includes a filling material. The filling material may include 1 conventional filling material such as ground glass, calcium carbonate, ATH, talc, bentonite, antimony trioxide, kaolin, ash, or other known filling materials. In 3 practice of the present invention, the appropriate filler filler in PU latex can be from 100 to 1000 parts to 100 parts of polyurethane. Preferably, the filler 5 may be loaded in an amount of at least 200 parts to 100 parts polyol, better than at least 300 parts percent, best not less than 400 parts by weight. 7

The invention also optionally includes a filling and wetting material. A filling and wetting material generally plays the role of compatibility function between the filling agent and the polyurethane composition. Useful humectants include phosphate salts such as sodium hexametaphosphate. The filling and wetting material may be included in the composition comprising polyurethane of the present invention in a concentration of at least 0.5 parts per 100 parts of filling material, in. 13

The invention optionally includes thickening agents. Thickening agents are useful in the invention for increasing the viscosity of low-viscosity PU latexes. The bulk agents suitable for use in the practice of the invention are any of those known in the field of polyurethane latex preparation. For example, suitable thickening agents 17 include Alcogum TM VEP-II (trademark of Alco Chemical Corporation) and TM Pargum (trademark of Para-Chem Southern, Inc.). The thickening agents can be used in any quantity necessary to obtain a desired viscosity dispersion.

The invention may optionally include other components. For example, the polyurethane-forming composition of the present invention may include surfactants, expansion agents or flame retardants, pigments, antistatic, hardening fibers, antioxidants, preservatives, 23 cleaning acids. Suitable expansion agents include gases such as carbon dioxide from air, nitrogen, argon, helium; liquids such as water, volatile halogenated alkanes as different chlorofluoromethanes 25 and chlorofluoroethanes; azo-expanding agents such as azobis (formamide). In the practice of this invention, it is preferred to use a gas as an expansion agent or foaming agent. Pre-rail, in particular, is the use of air as an expansion or foaming agent. A foaming agent may differ from an expanding agent in that the foaming agents are typically introduced at the mechanical introduction of a gas into a liquid to form a foam. 31

Surfactants may be desired in the present invention. Useful surfactants can be cationic surfactants, anionic surfactants or non-ionic surfactants. Examples of anionic surfactants include 33 sulfonates, carboxylates and phosphates. Examples of cationic surfactants include quaternary amines. Examples of non-ionic surfactants include block copolymers containing ethylene oxide and 35 silicone surfactants. The surfactants useful in the practice of the present invention may be either external or internal surfactants. External surfactants are surfactants that do not react chemically in the polymer during the preparation of latex. Internal surfactants are surfactants that react chemically in the polymer during the preparation of latex. A surfactant can be included in a formulation of the invention in a quantity of from 0.01 to 20 parts per 100 parts by weight of a polyurethane component. 41 In general, any method known to those skilled in the art of preparing polyurethane latexes can be used in the practice of the present invention to prepare PU latex material 43 suitable for making a carpet according to the invention, with the notable exception of using an organic solvent. Preferably, no organic solvent is used in the latex preparation process of the present invention.

RO 120414 Β1

A stable PU latex at storage, as defined here, is any PU latex with an average particle size of less than 5μ. A latex PU that is not stable for storage can have an average particle size greater than 5μ. For example, a suitable dispersion can be prepared by mixing a polyurethane prepolymer with water and dispersing the prepolymer in water using a commercial mixer. Alternatively, a suitable dispersion can be prepared by feeding a prepolymer into a static mixing device at the same time with water, and dispersing the water and prepolymer in the static mixer. Continuous methods for preparing aqueous polyurethane dispersions are known and may be used in practice from the present invention. For example, US Patent Nos. 4857565; 4742095; 4879322; 3437624; 6037864; 4221710; 4237264 and 4092286 all describe continuous processes useful for obtaining polyurethane latexes. In addition, a polyurethane latex having a high internal phase ratio can be prepared by a continuous process as described in US Pat. No. 5,590,9021, included herein by reference.

In the practice of the present invention, any of the steps used in the preparation of the polyurethane carpet support can be carried out in a continuous manner. For example, in a first step, the prepolymer may be prepared from a suitable compound containing continuously active hydrogen; the prepolymer can be fed and is obtained in the first step, in a water mixing device, to obtain an aqueous dispersion; the aqueous dispersion can be applied to the substrate of the continuous carpet to obtain a carpet on polyurethane support.

A polyurethane dispersion of the present invention can be stored for further application on the back of the carpet. Storage for this purpose requires that the dispersion be stable at storage. Alternatively, polyurethane latex can be applied continuously to the back of the carpet substrate. That is, the dispersion that can be applied to the carpet support as a dispersion is obtained according to the practice of the present invention. Polyurethane latexes applied on a continuous carpet need not be stable for storage, and may have a higher solids content and a larger average particle size or, alternatively, a larger average particle size than typical, stable polyurethane latex formulas. on storage.

In the preparation of carpets with polymeric support, according to the invention, a composition is formed which forms polyurethane as a preferable layer of uniform thickness on one of the surfaces of the carpet substrate. The PU latexes of the invention can be applied as a pre-coating, laminate or foam coating. Polyurethane pre-coatings, laminate coatings, and foam coatings can be prepared by processes known in the art. Pre-coatings, laminate coatings and foam coatings made from latex are described for example in P. L. Fitzgerald, Integral Latex Foam Carpet Cushioning ”, 1 Coat. Fab. 1977, You. Ί (pp. 107 - 120), and in R. P. Brentin, Latex Coating Systtems for Carpet Backing, J. Coat. Fab. 1982, vol. 12 (pages 82-91). When preparing a polyurethane foam support, it is preferable to mix all the components and then bubble a gas in the mixture, using as an equipment an Oakes or Firestone type foam generator.

The polyurethane forming composition can be applied to one of the surfaces of the carpet substrate before reaching the state of free rigidity. Alternatively, a PU latex containing an unreacted isocyanate function can be applied, thus removing the need for polymer treatment. Usually the composition from which polyurethane is formed is applied to the surface attached to a primary support. The composition can be applied to the carpet substrate using equipment such as a scalpel, pneumatic knife or extruder to apply and calibrate the layer. Alternatively, the composition may be formed in a layer, on a moving tape or other device, and dehydrated, or partially treated, or both dehydrated and partially treated, and then bonded to the carpet substrate using a double-tape laminator or moving tape with foam cushion applied. The amount of composition from which it is

EN 120414 Β1 forms polyurethane used can vary widely, between 16.95 and 1695 mg / cm ² (5 to 500 ounces 1 per square yard), depending on the characteristics of the textile material. After the layer is applied and calibrated, the water from the dispersion is removed and the layer can be treated by heating with any 3 suitable sources of heating such as an infrared oven, a convection heating oven, or heating plates. 5

The invention is further presented based on the embodiments shown in FIG.

The examples are not intended to limit the scope of the present invention and should not therefore be interpreted. Materials used in these examples are defined below:

Voranol 4702 = 1650 equivalents by weight, 16% triol EO9

Voranol 4701 = 1650 equivalents by weight, 18% triolEO

Voranol 2120 = 1000 weight equivalents, diol PO11

Isocyanate 50 = 50/50 weight / weight mixture of 2,4'-MDI and 4 4-MDI

All reports and weight percentages in the examples are expressed by weight, 13 unless otherwise stated.

Example 1. The following procedures were conducted at ambient temperature (19 ° C) .15

Prepolymer A was continuously fed at a rate of 32.1 g / min through a first arm bound to a first T, DeSULF ™ DBS-60T surfactant was fed (60% aqueous solution of tri-17-tansolamine dodecylbenzene sulfonate, brand registered by DeForest Enteerprises, Inc.) with a speed of 1.61 g / min through a first arm of a second T, and joined with a current of 19 steam flowing at a speed of 5.5 g / min through - a second arm of the second T. The prepolymer current and the water / surfactant current were joined to the first T, passed through a static static mixer and were fed through the inlet pipe of the dispersion instrument. IKASD 41 SUPER-DISPAX ™ (trademark IKA-WORKS, inc), a rotor / stator 23 device operated at 1200 rpm.

The feed ratios in the dispersion instrument were 81.9% prepolymer, 25%, 4.1% surfactant solution, and 14% water. The HIPR emulsion formed in the dispersion instrument had an average particle size of 0.265μ and a polydispersion of 34 / measured 27 with a Goulter LS 130 particle size analyzer.

The chain extension was carried out in a linear mixer model LIGHTNIN 29 TM, 125 LB (registered trademark GREEY / LIGHTNIN). The HIPR emulsion from the dispersion instrument was fed into a first arm attached to a third T and joined with an aqueous stream 31 fed through the second arm of the third T with a flow rate of 5.1 g / min. The product of the combined currents was supplied in a single arm of a fourth T, which was attached 33 at the inlet of the linear mixer. Simultaneously, a 10% aqueous solution of piperazine was pumped at a constant flow rate of 18.0 g / min (0.75 equivalents, based on the isocyanate groups of 35 prepolymers) through the other arm of the fourth T. The two currents were mixed in the linear mixer operating at 1500 rpm. The product was collected and allowed to stand for more than 37 nights, in order for the water to react with the remaining isocyanate groups. The resulting stable poly (urethane / urea) latex had a solids content of 55% by weight, an average particle size 39 of 0.256μ, and a polydispersibility of 3.5, as measured by a particle size analyzer. particle Coulter LS 230. 41

The latex was made by mixing 178.6 parts of latex (100 parts of solids) with 200 parts of calcium carbonate as a filler. Stirring was started with only 43 latex, then the filler was added so quickly that it was dispersed in the liquid. Paragum ™ 241 thickening agent (registered trademark of Para-Chem Southern, Inc.) 45 was added until the viscosity of 9300 cPs (93, Ns / m ² ) was reached. The test mat was curved in nylon with a weight of 77.98 mg / cm ² (23 square yards). 47 The compound was applied on the support of this carpet with a weight layer of 118.7 mg / cm ²

RO 120414 Β1 (35 ounces per square yard), followed by a polypropylene mesh (mesh), 11.19 mg / cm ² (3.3 ounces per square yard), as a secondary support. The carpet was dried at 132 ° C for 12 min, then left overnight before testing.

The carpet in Example 1 had a 2.97 kg-meter (21.5 ft-pounds) bonding. The values of bonding the brushes were obtained according to ASTM D1335. The carpet in Example 1 had a dry exfoliation of 1,803 kg / cm (10.1 pounds / inch) and a wet re-exfoliation of 892.9 kg / cm (5.0 pounds / inch). Exfoliation was determined to be the force required to remove the polypropylene secondary mesh (net) from the fabricated carpet, It was determined by cutting 7.62 cm by 22.86 cm (3 inches by 9 inches) from the carpet, and peeling the net secondary from the main portion of the carpet while the required force is measured. Exfoliation at wetting was determined in the same manner, except that the carpet sample was soaked for one minute in water and drained for drying before testing. The carpet in example 1 had a manual punch of 2.04 kg-meters (17.4 fts-pounds). Manual punching was measured as the force required to push a piece of 22.86 cm by 22.86 cm (9 inches by 9 inches) from a carpet of 1.27 cm (0.5 inches) through an inner diameter cylinder of 13.97 cm (5.5 inches) with a speed of 30.48 cm / min (12.0 inches per minute), using a solid cylinder with an outer diameter of 5.715 cm (2.25 inches) ) attached by a load cell.

Example 2. The process used to prepare the latex in Example 1 was repeated, with the following exceptions. The surfactant was DeSULF TM TLS-40 (a 40% aqueous solution of triethanolamine lauryl sulfate, brand DeForest Enterprises, Inc.) and the flow rates were: prepolymer, 32.0 g / min; surfactant, 2.4 g / min; and water, 3.5 g / min. The ratios of the components that were fed into the disperser were prepolymer, 84.4%; surfactant solution, 6.3%; and water, 9.2%. The HIPR emulsion had an average particle size of 0.182μ and a polydispersibility of 1.6, measured with a Coulter LS 130 particle size analyzer.

The steam stream used to dilute the HIPR emulsion moved at a speed of 4.6 g / min, and the piperazine solution was pumped at a speed of 17.9 g / min. The final poly (urethane / urea) latex had a solids content of 53.9% by weight, and an average particle size of 0.365µ.

The latex was made as in Example 1. Paragum ™ 241 thickening agent (from Para-Chem Southern, Inc.) was added until a viscosity of 8,000 to 10,000 cPs (80 - 100Ns / m ² ) was reached. ). The compound was applied to the support of the same carpet as in Example 1 with a film weight of 121.0 mg / cm ² (35.7 ounces per square yard), followed by a polypropylene mesh, 11.19 mg / cm ² (3 , 3 ounces per square yard), as a secondary support. The carpet was dried at 132 ° C for 12 min, then allowed to equilibrate overnight before testing. This rug has a pearl binding of 23.92 kg-meters (21.1 ft-pounds), a hand punch of 2.36 kg-meters (17.1 ft-pounds); a dry delamination of 1.7379 kg / cm (9.9 pounds / inch) and a wet re-exfoliation of 1.3036 kg / cm (7.3 pounds / inch).

Comparative example 3. For comparison, a standard latex styrene butadiene carpet (contained in 53.3% solids) was mixed with calcium carbonate and a thickening agent and applied as a carpet support as in the example! 1. The resultant carpet had a weight coverage of 115.6 mg / cm ² (34.1 ounces per square yard), 2.24 kg-meters (16.2 ft-pounds) brushing, 1 peeling , 7501 kg / cm (9.8 pounds / inch), a manual punch of 3.37 kg-meters (27.0 ft-pounds) and a wet re-exfoliation of 1.1786 kg / cm (6.6 pounds / inch) ).

Claims (10)

1. Process for making a carpet on the substrate, characterized in that it comprises the steps: (1) dispersing a polyurethane prepolymer in water to obtain an aqueous dispersion of the prepolymer; (2) applying aqueous dispersion on the back of the substrate of a carpet; (3) removing the water from the aqueous dispersion to obtain a carpet on the support, in which the latex is prepared in the substantial absence of an organic solvent. RO 120414 Β1 Process according to Claim 1, characterized in that the dispersion includes a 1 surfactant. Process according to claim 2, characterized in that the dispersion includes a chain extension 3. Process according to claim 3, characterized in that the dispersion is prepared by a continuous process. 5. Process according to claim 4, characterized in that the dispersion is applied continuously to the carpet substrate. 6. Process according to claim 4, characterized in that the prepolymer is prepared by a continuous process, by mixing the polyols, polyisocyanates and, optionally, the catalyst before dispersing in water.11 Process according to claim 3, characterized in that the chain extension is a polyamine. Process according to claim 1, characterized in that the prepolymer is dispersed in a mixture of water and filling material. 9. Process according to claim 1, characterized in that at least a fraction of the isocyanate function of the prepolymer is unreacted when applied to the sublayer of the carpet. Process according to claim 1, characterized in that the aqueous dispersion 19 of the prepolymer is mixed with a filling material and optional additives, in a step preceding the application of the dispersion on the substrate of the carpet substrate. 21