Precoat resin dispersion for tufted carpets

This invention relates to chemical compositions. Particularly, this invention relates to novel precoat resin dispersions useful in the manufacture of tufted textile articles, such as, tufted carpets.

When the tufted article is a carpet, the primary backing fabric is tyically a woven or nonwoven fabric made of one or more of natural and synthetic fibers, such as jute, wool, rayon, polyamides, polyesters, polypropylene and polyethylene, or of films of synthetic materials, such as polypropylene, polyethylene, and copolymers thereof.

The tufts of yarn inserted during the tufting process are usually held in place by the untwisting action of the yarn in combination with the shrinkage of the backing fabric. However, when the article is a tufted carpet, the back of the backing fabric may be coated with a backcoat material, such as a latex or emulsion of natural or synthetic rubbers or synthetic resins, or a hot melt adhesive, to assist in locking or anchoring the tufts to the backing material, to improve the dimensional stability of the tufted carpet, to make the carpet more durable and to provide skid and slip resistance.

Generally, the tufted carpet is further stabilized by laminating a secondary backing, such as jute, woven or nonwoven fabrics made from polypropylene, polyethylene, and copolymers thereof, to the tufted carpet.

Carpets bonded with a synthetic rubber or synthetic rubber latex generally do not employ precoat compositions, such as precoat resin dispersions, in their manufacture. When precoat compositions are used, they are applied to the backside of the primary backing in an amount sufficient to penetrate the individual tufts of yarn thereby increasing the resistance of the tufts to pull-out, known as tuft-bond strength or pile-bond strength, and enhancing the bonding of the primary backing fabric to the backcoating material. The amount of precoat necessary to penetrate the individual tufts will vary depending on the carpet yarn density and the efficacy of the precoat.

Up until this point, the use of a latex, wherein the resin has a multiplicity of carboxyl groups, such as a carboxylated styrene-butadiene latex, together with a cationic polyamide-epichlorohydrin resin as the crosslinking agent as disclosed in U.S. 3,338,858, have failed for one reason or another. Basically the mixture of carboxylated latices and cationic resin have such a low shelf life that the mixture partially or completely crosslinks in its shipping container before it can even be brought into close proximity to let alone actual contact with, the tufts on the backside of the tufted primary backing.

According to the present invention, a precoat resin dispersion having a solids content from 63% to 69% characterized in that it contains, by weight, (1) from 93% to 99% of at least one resin material selected from hydrocarbon resins prepared from petroleum refined streams, polyterpene resin or esters of rosin having a Ring & Ball softening point from 60°C to 100°C, which resin material is an aqueous dispersion having from 53% to 58% solids content; (2) from 0.5% to 5%, based on the total water content of (1), of at least one water-soluble polymer selected from polyacrylates and cellulose derivatives; (3) from 0.1 % to 2% of at least one polyamide-epichlorohydrin cationic resin, based on the total solids content of (1); and (4) optionally, sufficient water so that the solids content of the precoat resin dispersion is from 63% to 69%. Preferably the precoat resin dispersion of this invention has a solids content from 64% to 67% and comprises from 94% to 97% of component (1) with the solids content af component (1) being from 54% to 56%; 1.5% to 2.5% of component (2); and from 0.5 to 1.5% of component (3).

The precoat resin dispersion of this invention improves the tuft-bond strength, narrows the statistical variation of tuft bond values and increases the stiffness and durability of carpets backcoated with carboxylated rubber latices. Further, the precoat resin dispersion of this invention allows the cationic resin crosslinking agent to penetrate to tufts on the backside of the tufted primary backing prior to the coating and penetration of the same tufts with a carboxylated latex. Hence, the precoat resin dispersion of this invention when applied as a precoat in the manufacture of tufted carpets eliminates the opportunity for any premature crossliking between the cationic resin crosslinking agent and the carboxylated latex, i.e. any crosslinking other than at the site of the tuft on the backside of the primary backing fabric.

Any conventional method for preparing resin dispersions may be used to prepare the aqueous resin dispersion of component (1). Suitable methods are taught in U.S. Patent 3,582,464. Typically, when component (1) is an ester of rosin, an aqueous solution of potassium hydroxide is added to a molten resin in an amount sufficient to provide, by weight, from about 1% to 8% potassium resinate. Water, optionally containing an emulsifying agent, is then added in an amount sufficient to provide, by inversion, an oil-in-water type emulsion having a solids content from about 53% to about 58%. When component (1) is a hydrocarbon resin prepared from petroleum refined streams or a polyterpene resin, an aqueous solution of potassium hydroxide is added to a molten resin admixed with 1% to about 6% of a rosin or rosin ester in an amount sufficient to provide, by weight, from about 1 % to about 6% potassium resinate. Water is then added in an amount sufficient to provide, by inversion, an oil-in-water type emulsion having a solids content from 53% to 58%.

The precoat resin dispersion is particularly useful in the manufacture of carpets wherein carboxylated styrene-butadiene latices are used to coat the tufted primary backing fabric prior to lamination with the secondary backing fabrics. Generally the carboxylated styrene-butadiene latices contain up to 700 parts per hundred of a mineral filler.

All parts and percentages used in this disclosure and in the claims are by weight unless otherwise specified.

Component (1) of the precoat resin dispersion of this invention is at least one hydrocarbon resin prepared from petroleum refined steams, polyterpene resins or esters of rosin having a Ring and Ball softening point from 60°C to 100°C in an aqueous dispersion of 53% to 58% solids. Suitable hydrocarbon resins include those hydrocarbon resins prepared by polymerizing the component mixture of a blend of a five carbon stream and a nine carbon stream from petroleum refining, commonly referred to as a C_S-Cg stream. Hence, the hydrocarbon resins prepared from such a stream are commonly referred to as C₅ C₉ resins. The components of a C_S-Cg stream are unsaturated aliphatic and vinyl aromatic hydrocarbon compounds, both normal and branched, in which the number of carbons generally does not exceed nine. Other suitable hydrocarbon resins include hydrocarbon resins prepared by polymerizing the monomer mixture of a five carbon component stream, known as a C₅ stream, from petroleum refining, the monomers being primarily unsaturated aliphatic. The resins hydrocarbon prepared from a C₅ stream are commonly referred to as C₅ resins. The primary monomers present in a C₅ stream are di- and mono-olefins, both normal and branched, having five carbons and monooolefins having six carbons. The preferred hydrocarbon resin is the C₅ resin.

Typical polyterpene resins are those derived from alphapinene, beta-pinene, and monocyclic terpenes such as dipentene.

Suitable esters of rosin include the methyl ester of rosin, the methyl ester of hydrogenated rosin, the triethylene glycol ester of rosin, the triethylene glycol ester of hydrogenated rosin, the diethylene glycol ester of rosin, the diethylene glycol ester of hydrogenated rosin, the ethylene glycol ester of rosin and the ethylene glycol ester of hydrogenated rosin, the glycerol ester of rosin and the pentaerythritol ester of rosin. The preferred ester of rosin is the glycerol ester of resin.

Component (2) of the precoat resin dispersion of this invention is at least one water-soluble polymer having a molecular weight from about 100 to about 10,000. The polymer is selected from polyacrylates, such as polysodium acrylate, and celulose derivatives, such as carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylhydroxyethylcellulose, methylhydroxypropylcellulose, carboxymethylhydroxyethylcellulose, hydroxypropyl- hydroxyethylcellulose, and hydrophobically modified hydroxyethylcellulose. Usually component (2) is added to component (1) as an aqueous dispersion of from about4% to about 7% solids.

Comoonent (3) of the orecoat resin dispersion of this invention is at least one polyamide-epichlorohydrin cationic resin, preferably one having a RVF Bookfield viscosity at 25°C of from 0.05 to 0.325 Pas (from 50 centipoise (cps) to 325 cps), most preferably from 0.05 to 0.1 Pas (from 50 cps to 100 cps). The cationic resin is a polyamide- ephichlorohydrin resin. The polyamide-epichlorohydrin resin can be prepared by reacting a saturated aliphatic dicarboxylic acid with a polyalkylene amine to form a linear polyamide, and then reacting the polyamide with epichlorohydrin. Suitable methods of preparation are set forth in U.S. Patent 2,926,154 and 3,966,654. Typical polyamides include copolymers of adipic acid and diethylenetriamine or adipic acid with diethylene- triamine and ethylenediamine. Polyamide as used herein includes copolymers and terpolymers: Generally component (3) is added as an aqueous dispersion of from about 3% to about 7% solids.

In addition, small amounts of conventional additives, such as antioxidants, surfactants, flocculants, fillers and the like can be included in the precoat resin dispersions.

The following examples illustrate various aspects of this invention. They are not intended to limit the invention. Modifications of the specific precoat resin dispersions, carpets prepared with the precoat resin dispersions and procedures of these examples can be made without departing from the scope of this invention.

Example 1

This example illustrates a preferred specific embodiment of the precoat resin dispersion of this invention, and how to prepare it.

A mixing container affixed with a stirrer is charged with 92.5 g of the glycerol ester of a 50% hydrogenated rosin having a Ring and Ball softening point of 80°C in an aqueous dispersion, the total solids content of the aqueous dispersion being approximately 55% and prepared as set forth herein above. Stirring is continued throughout all additions until a precoat resin dispersion of this invention is formed. Two (2)%, based on the total water of the aqueous dispersion containing the resin, of a polysodium acrylate, also in a dispersion which is diluted with water to a 5.7% solids content, is added to the first aqueous dispersion, followed by the addition of 1% of an (adipic acid-diethylene-triamine) polyamide-epichlorohydrin resin having a viscosity of 0.05 Pas (50 cps) at 25°C in a yet another aqueous dispersion diluted with water to a 5.0% solids content, thereby providing a precoat resin dispersion of this invention.

Example 2

This example illustrates another specific embodiment of the precoat resin dispersion this invention. The precoat resin dispersion is prepared according to the formulation and procedure of Example 1 except that a 65% hydrogenated glycerol ester of rosin having a Ring and Ball softening point of 82°C is used instead of the 50% hvdroaenated qlvcerol ester of rosin.

Example 3

This example illustrates another embodiment of this invention. The precoat resin dispersion is prepared according to the formulation and procedure of Example 1 except that an aliphatic hydrocarbon resin having a Ring and Ball softening point of 85°C is used instead of the glycerol ester of a 50% hydrogenated rosin.

Example 4

This example illustrates another embodiment of this invention. The precoat resin dispersion is prepared according to the formulation and procedure of Example 1 except that an aromatic hydrocarbon resin having a Ring and Ball softening point of 95°C is used instead of the glycerol ester of a 50% hydrogenated rosin.

Example 5

This example illustrates another embodiment of this invention. The precoat resin dispersion is prepared according to the formulation and procedure of Example 1 except that a 65% hydrogenated pentaerythritol ester of rosin having a Ring and Ball softening point of 82°C is used instead of the 50% hydrogenated rosin, except that 0.5% of the polysodium acrylate is used instead of 2%, and except that a polyamide-epichlorohydrin resin having a RVF Brookfield viscosity of 0.325 Pas (325)cps at 25°C, where the polyamide is terpolymer of adipic acid, diethylenetriamine, and ethylenediamine, is used instead of one having a viscosity of 0.05 Pas (50 cps) at 25°C.

Example 6

This example illustrates another embodiment of this invention. The precoat resin dispersion is prepared according to the procedure of Example 1 using the formulation of Example 2 except that 0.5% of the polysodium acrylate is used instead of 2%, and except that a polyamide-epichlorohydrin resin having a RVF Brookfield viscosity of 0.085 Pas (85 cps) at 25°C, where the polyamide is terpolymer of adipic acid, diethylenetriamine, and ethylenediamine, is used instead of one having a viscosity of 0.05 Pas (50 cps) at 25°C.

Example 7

This example illustrates another embodiment of this invention. The precoat resin dispersion is prepared according to the procedure of Example 1 using the formulation of Example 2 except that 3% of a hydroxyethylcellulose is used instead of 2% of a polysodium acrylate dispersion.

Example 8

This example illustrates another embodiment of this invention. The precoat resin dispersion is prepared according to the procedure of Example 1 using the formulation of Example 2 except that 1 % of a hydroxycellulose is used instead of 2% of a polysodium acrylate dispersion.

Example 9

This example illustrates another embodiment of this invention. The precoat resin dispersion is prepared according to the procedure of Example 1 using the formulation of Example 2 except that 2% of a hydroxyethylcellulose is used instead of 2% of a polysodium acrylate dispersion.

Example 10

This example illustrates another embodiment of this invention. The precoat resin dispersion is prepared according to the procedure of Example 1 using the formulation of Example 2 except that 1% of a sodium salt of carboxymethylcellulose (CMC) is used instead of 2% of a polysodium acrylate dispersion.

Example 11

This example illustrates another embodiment of this invention. The precoat resin dispersion is prepared according to the procedure of Example 1 using the formulation of Example 2 except that 3% of a CMC is used instead of 2% of a polysodium acrylate dispersion.

Example 12

This example illustrates another embodiment of this invention. The precoat resin dispersion is prepared according to the procedure of Example 1 using the formulation of Example 2 except that 2% of a CMC is used instead of 2% of a polysodium acrylate dispersion.

Example 13

This example shows the tuft bond strength of finished carpets prepared with the precoat resin dispersion of this invention and a carboxylated styrene-butadiene rubber latex as the backcoat.

Carpet specimens are prepared according to the procedures of ANSI/ASTM D1335-67 using 331 g/m² (10 oz.!yd.²) of the precoat resin dispersion of Example 1 as the precoat and then applying 814 g/M² (24 oz.!yd.²) of the carboxylated styrene-butadiene rubber latex as the backcoat and, as the control, a carpet specimen prepared in the same manner without the precoat, but backcoated with 814 g/m² (24 oz/yd.²) of the carboxylated styrene-butadiene rubber latex. The carpet text specimens are mounted and tested for tuft bond strength according to ANSI/ASTM D1335-67. Basically, this test measures the amount of force required to separate individual pile yarns from the carpet. The tuft bond strength of the control carpet test specimen is 5.45-7.26 (12-16 lbs); whereas the carpet test specimen with the precoat resin dispersion of this invention is 9.99-11.80 kg (22-26 lbs).

Other features, advantages and specific embodiments of this invention will become apparent to those exercising ordinary skill in the art after reading the foregoing disclosures. Such specific embodiments are within the scope of this invention. Moreover, while specific embodiments of the invention have been described in considerable detail, it is not limited thereto, and variations and modifications of those embodiments can be effected without departing from the scope of the invention.