Divalent Metal Salts of Sulfonated Novolak Resins and Methods for Treating Fibrous Polyamide Materials Therewith

The following non-limiting examples serve to illustrate the invention. In the following examples, all ratios are by weight and percentages are weight percent unless otherwise indicated. In the examples where the material being treated is nylon 66 carpet, the carpet is scoured, greige, unbacked, level-loop carpet unless otherwise indicated.

To a three-neck flask, fitted with a mechanical stirrer, thermometer, and condenser, were added 473 g of acetic anhydride and 945 g of 4,4'-dihydroxydiphenylsulfone. Then 473 g of concentrated sulfuric acid were added via a dropping funnel over a period of one hour with stirring. The resulting reaction mixture was heated and stirred at 100.degree. C. for 7 hours. Water (340 g) was added in portions while distilling off acetic acid over one hour. After addition of 250 g of 37% aqueous formaldehyde and 338 g of water, the reaction mixture was heated to 100.degree. C. for 6 hours. The resulting sulfonated 4,4'-dihydroxydiphenylsulfone-formaldehyde condensate was diluted with 1400 g of water and neutralized to a pH of 5.5 with 182 g of magnesium oxide to yield the substantially sulfonic acid-free, water-soluble magnesium salt of the partially sulfonated novolak resin product as a 41% aqueous concentrate.

The procedure of Example 1 was followed except that 204 g of zinc oxide were used to neutralize the sulfonated 4,4'-dihydroxydiphenylsulfone-formaldehyde condensate to a pH of 4.9 to yield the substantially sulfonic acid-free, water-soluble zinc salt of the partially sulfonated novolak resin product as an aqueous solution having a solids concentration of 42.4%.

The procedure of Example 1 was followed except that 423 g of calcium hydroxide was used to neutralize the sulfonated 4,4'-dihydroxydiphenylsulfone-formaldehyde condensate to a pH of 6.4 to yield the substantially sulfonic acid-free, water-soluble calcium salt of the partially sulfonated novolak resin product as an aqueous solution having a solids concentration of 16.2% after removal of precipitated calcium sulfate.

To a three-neck flask, fitted with a mechanical stirrer, thermometer, and condenser, were added 313 g of acetic anhydride and 625 g of 4,4-dihydroxydiphenylsulfone. Then 245 g of concentrated sulfuric acid were added via a dropping funnel over a period of one hour with stirring. The resulting reaction mixture was heated and stirred at 100.degree. C. for 10 hours. Water (669 g) was added in portions while distilling off acetic acid over one hour. After addition of 145 g of 37% aqueous formaldehyde and 223 g of water, the reaction mixture was heated to 100.degree. C. for 6 hours. The resulting sulfonated 4,4'-dihydroxydiphenyl-sulfone-formaldehyde condensate was diluted with 990 g of water and neutralized to a pH of 5.2 with 87 g of magnesium oxide to yield the substantially sulfonic acid-free, water-soluble magnesium salt of the partially sulfonated novolak resin product as a 41.3% aqueous concentrate.

The procedure of Example 4 was followed except that 177 g of zinc oxide were used to neutralize the sulfonated 4,4'-dihydroxydiphenylsulfone-formaldehyde condensate to a pH of 5.3 to yield the substantially sulfonic acid-free, water-soluble zinc salt of the partially sulfonated novolak resin product as an aqueous solution having a solids concentration of 41.6%.

To a three-neck flask, fitted with a mechanical stirrer, thermometer, and condenser were added 94 g phenol and 98 g concentrated sulfuric acid and the mixture was stirred and heated at 100.degree. C. for two hours under nitrogen atmosphere to form phenolsulfonic acid. To this reaction mixture were added 193 g water and 37 g calcium hydroxide and this mixture was stirred and heated at 95.degree. C. for two hours. The reaction mixture was filtered to remove precipitated calcium sulfate to yield a 39.4% aqueous solution of the phenolsulfonic acid calcium salt. A portion of this salt solution (98 g containing 38.6 g salt), 70 g 4,4'-dihydroxydiphenylsulfone, 38.5 g of 37% aqueous formaldehyde, and 7.4 g calcium hydroxide were reacted for 15 hours at 97.degree. C. under nitrogen atmosphere to form the substantially sulfonic acid-free, water-soluble sulfonated 4,4'-dihydroxydiphenylsulfone-formaldehyde calcium salt. This calcium salt product was diluted to 30% solids using 106 g water and the pH was adjusted to 7.6 with 3.5 g calcium hydroxide.

The procedure of Example 1 was followed except that the sulfonated 4,4'-dihydroxydiphenylsulfone-formadehyde condensate was neutralized to a pH of 6.0 with 550 g of 50% sodium hydroxide to yield the sodium salt of the condensate as a 36% aqueous concentrate.

A sodium salt of condensation product similar to that of Ex. 6 was prepared, following the general procedure of Ex. 6 from 31 grams of phenolsulfonic acid monohydrate, 60 g of 4,4'-dihydroxydiphenyl sulfone, 31 g of 37% aqueous formaldehyde and 35 g of 50% sodium hydroxide to yield a 37.2% concentrate of sodium salt of the condensation product.

In the following examples, fibrous polyamide materials were evaluated using the following test methods:

One-hour test: A 1 g sample of the fibrous polyamide material under evaluation is placed in 40 ml aqueous solution containing 0.008 weight percent FD&C Red Dye No. 40 and 0.04 weight percent citric acid at room temperature (22.degree. C.) and agitated for one hour. The sample is removed from the dye solution, rinsed and blotted with paper towels to remove excess moisture. The amount of staining is evaluated visually using a rating scale which ranges from 1-5, where 1 is essentially unstained and 5 is heavily stained. Generally, a stain resistance of less than 3 is satisfactory.

Eight-hour test: Ten ml of an aqueous solution containing 0.008 weight percent FD&C Red Dye No. 40 and 0.04 weight percent citric acid is poured onto the test sample and pressed into the sample using the rounded end of a 1.75 cm diameter test tube. The solution is allowed to remain on the test sample for eight hours at room temperature, i.e., about 22.degree. C. The sample is rinsed under running tap water and then evaluated for staining using a graduated rating scale which ranges from 1 to 8, where 1 represents no discernable removal of the red dye stain and 8 represents complete removal of the red dye stain. In general, an eight-hour stain resistance of at least 4 is satisfactory.

The water repellency of treated polyamide samples is measured using a water/isopropyl alcohol test, and is expressed in terms of a water repellency rating on a scale of 0 to 10 of the treated carpet or fabric. Treated carpets which are penetrated by or resistant only to a 100 percent water/0 percent isopropyl alcohol mixture (the least penetrating of the test mixtures) are given a rating of 0, whereas treated fabrics resistant to a 0 percent water/100 percent isopropyl alcohol mixture (the most penetrating of the test mixtures) are given a rating of 10. Other intermediate values are determined by use of other water/isopropyl alcohol mixtures, in which the percentage amounts of water and isopropyl alcohol are each multiples of 10. The water repellency rating corresponds to the most penetrating mixture which does not penetrate or wet the fabric after 10 seconds contact. In general, a water repellency rating of at least 1, is desirable for carpet.

The oil repellency of the treated polyamide samples is measured by a modified AATCC Standard Test 118-1978, which test is based on the resistance of treated fabric to penetration by oils of varying surface tensions. Treated fabrics resistant only to "Nujol", a brand of mineral oil and the least penetrating of the test oils, are given a rating of 1, whereas treated fabrics resistant to heptane (the most penetrating of the test oils) are given a value of 8. Other intermediate values are determined by use of other pure oils or mixtures of oils. The rated oil repellency corresponds to the most penetrating oil (or mixture of oils) which does not penetrate or wet the fabric after 10 seconds contact rather than the 30 seconds contact of the Standard Test. Higher numbers indicate better oil repellency. Additionally, a value of 0 indicates no resistance to "Nujol". In general, an oil repellency of at least 1 or greater is desirable for carpet.

Samples of nylon 66 level-loop carpet which had been heat-set for 90 seconds at 195.degree. C. and 30% relative humidity were immersed in aqueous baths containing various novolak salts. In Comparative Examples C4-C7, the sodium novolak salt of Comparative Example 1 was used. In Examples 7-10, the magnesium novolak salt of Example 1 was used. In Examples 11-14, the zinc novolak salt of Example 2 was used. In Examples 15-18, the calcium novolak salt of Example 3 was used. The type of salt, i.e., metal ion present, and amount are set forth in Table I. Each sample was immersed in the aqueous bath for 90 minutes at 97.degree. C. at pH 5 (adjusted with acetic acid) using a 20:1 liquor to fabric ratio. For Comparative Example 3, the sample was treated as described above except that no novolak salt was applied. The treated samples were rinsed, dried for 20 minutes at 70.degree. C. and 10 minutes at 130.degree. C. and tested for stain resistance using both the one-hour and eight-hour tests. The test results are set forth in Table I.

As can be seen from the data in Table I, the divalent novolak salts used in Example 7-18 generally provide improved stain resistance over the monovalent sodium novolak salt used in Comparative Examples C4-C7, particularly at the 0.25% and 0.35% solids owf concentrations.

Samples of nylon 66, level-loop carpet were heat set and treated as in Example 10, i.e., using 0.15% solids owf of the novolak calcium salt of Example 3, except that supplemental divalent metal salts, calcium chloride, magnesium acetate, and magnesium sulfate, as indicated in Table II, were added to the treating solution. Each sample was tested for one-hour and eight-hour stain resistance. The results are reported in Table II.

As can be seen from the data in Table II, the addition of supplemental divalent metal salts to the novolak salt-containing treatment bath generally provides increased stain resistance.

Samples of nylon 66 level loop carpet, heat set as in Examples 7-18, were treated with the calcium novolak salt of Example 3 in Examples 32-41 or the sodium novolak salt of Comparative Example 1 in Comparative Examples C8-C17 with the treatment procedure being the same as in Example 11, i.e., using 0.25% solids owf of the novolak salt except the pH of the treating bath was varied from 3 to 12 using acetic acid or sodium hydroxide as needed for pH adjustment. Samples were tested for stain resistance using the one-hour test. The solution pH and the stain resistance (SR) are reported in Table 3.

As can be seen from the data in Table III, the divalent calcium novolak salt provides stain resistance superior to that provided by use of the monovalent sodium novolak salt over a wider pH range and particularly in the pH range of 7-10.

Samples of nylon 66, level-loop carpet were prepared and treated as in Examples 32-41 and Comparative Examples C8-C17 except that 2% owf magnesium sulfate, a supplemental divalent metal salt, was added to the treatment bath. The samples were tested for stain resistance using the one-hour test. The solution pH and the stain resistance (SR) are reported in Table 4.

As can be seen from the data in Table IV, addition of the supplemental divalent metal salt, magnesium sulfate, improves stain resistance over a wider pH range when used with the divalent calcium novolak salt than when used with the monovalent sodium novolak salt.

Samples of nylon 66 level-loop carpet were treated by padding (80% wet pickup) an aqueous solution containing 0.3% solids owf of the magnesium novolak salt of Example 1 in Example 52 or the zinc novolak salt of Example 2 in Example 53. Each sample was dried for 20 minutes at 70.degree. C., heat set 5 minutes at 150.degree. C., mock dyed for 90 minutes at 97.degree. C., rinsed, and extracted, dried 20 minutes at 70.degree. C. and 10 minutes at 130.degree. C. The samples were then tested for stain resistance using the one-hour test. The carpet sample treated with the magnesium novolak salt had a stain resistance rating of 1.5 and the carpet sample treated with the zinc novolak salt had a stain resistance rating of 1-1.5, each showing excellent stain resistance.

Nylon 66, staple carpet fiber was treated with an aqueous emulsion of the zinc novolak salt of Example 2 and a fluorochemical for imparting oil and water repellency containing 25% FX-398 and 75% FX-399 (both fluorochemicals available from 3M Company) in combination with a 3.5% aqueous emulsion of a coconut oil-based fiber spin finish. The spin finish compositon was adjusted to provide 0.35% solids of the zinc novolak salt and 0.065% of the fluorochemical composition based on the weight of fiber. The spin finish was applied by a metered slot applicator. The treated yarn was heat-set under substantially dry conditions at 195.degree. C. for about one minute and made into 40 oz/yd.sup.2 cut pile saxony carpet, acid dyed, dried at 70.degree. C. for 30 minutes, heated at 130.degree. C. for 10 minutes and then evaluated for stain resistance using the eight hour test and for oil and water repellency. The stain resistance rating was 8, the oil repellency rating was 4, and the water repellency rating was 3.

Samples of nylon 66 level-loop carpet, heat set as in Examples 7-18, were treated as in Examples 7-18, using 0.3% solids owf of the calcium novolak salt of Example 6 in Example 55 and 0.3% solids owf of the sodium novolak salt of Comparative Example 2 in Comparative Example C28. The samples were tested for stain resistance using the one-hour test. The divalent calcium novolak salt provided a stain resistance rating of 1.5 while the monovalent sodium salt provided a stain resistance rating of 2.5.

Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention and this invention should not be restricted to that set forth herein for illustrative purposes.