Flexible, flat substrates having an abrasive surface

Abstract

Flexible, sheet-like substrates having an abrasive surface, which are obtainable by applying an aqueous solution or dispersion of at least one precondensate of a heat-curable resin to the top and/or bottom of a flexible, sheet-like substrate in an amount of at least 5 to 90% by weight, based on the uncoated, dry substrate, crosslinking the precondensate and drying the treated substrate.

Claims

1. A flexible, sheet-like cleaning substrate having an abrasive surface obtained by applying an aqueous solution or dispersion of at least one precondensate of a heat-curable resin to the top and/or bottom of a flexible, sheet-like substrate in an amount of at least 5 to 90% by weight, based on the uncoated, dry substrate, crosslinking the precondensate and drying the treated substrate wherein the abrasive surface has a structure that when the abrasive surface is pushed or moved on top of another surface, the abrasive surface cleans said another surface; wherein the heat-curable resin is a precondensate of melamine and formaldehyde in which the molar ratio of melamine to formaldehyde is greater than 1:2.

2. The flexible, sheet-like substrate according to claim 1, wherein the heat-curable resin used is a precondensate in which the molar ratio of melamine to formaldehyde is from 1:1.0 to 1:1.9.

3. The flexible, sheet-like substrate according to claim 1, wherein the substrate is selected from the group consisting of the nonwovens, woven fabrics, knitted fabrics, paper, board and cardboard.

4. The flexible, sheet-like substrate according to claim 1, wherein the substrate is paper or nonwoven comprising cellulose fibers.

5. The flexible, sheet-like substrate according to claim 1, wherein the solution or dispersion of the precondensate comprises at least one curing agent.

6. The flexible, sheet-like substrate according to claim 1, wherein the solution or dispersion of the precondensate comprises at least one surfactant.

7. The flexible, sheet-like substrate according to claim 1, wherein the solution or dispersion of the precondensate comprises from 0 to 20% by weight of at least one polymeric additive.

8. The flexible, sheet-like substrate according to claim 1, wherein the solution or dispersion of the precondensate is applied to the whole surface of the substrate.

9. A flexible, sheet-like cleaning substrate having an abrasive surface obtained by applying an aqueous solution or dispersion of at least one precondensate of a heat-curable resin to the top and/or bottom of a flexible, sheet-like substrate in an amount of at least 5 to 90% by weight, based on the uncoated, dry substrate, crosslinking the precondensate and drying the treated substrate wherein the abrasive surface has a structure that when the abrasive surface is pushed or moved on top of another surface, the abrasive surface cleans said another surface; wherein the aqueous solution or dispersion of the precondensate is applied in the form of a pattern to the substrate.

10. The flexible, sheet-like substrate according to claim 1, wherein the substrate treated with an aqueous solution of a precondensate is cured and dried at a temperature in the range of from 50 to 250 C.

11. The flexible, sheet-like substrate according to claim 1, wherein the amount of the heat-curable resin, based on the uncoated, dry substrate, is from 5 to 90% by weight.

12. A wiping cloth for cleaning surfaces in the household and in industry which comprises the flexible, sheet-like substrate according to claim 1.

13. The flexible, sheet-like substrate according to claim 1, wherein the substrate is used for cleaning surfaces in the household or the industry.

14. A process to clean a surface which comprises moving the abrasive surface of the flexible, sheet-like substrate according to claim 1 on another surface, wherein the abrasive surface cleans said another surface.

15. The flexible, sheet-like substrate according to claim 1, wherein the substrate has a scouring effect.

Description

EXAMPLES

Preparation Solution 1

(1) A 20% strength aqueous solution was prepared from a pulverulent precondensate of melamine and formaldehyde (Kauramin KMT 773 (powder, BASF)) and water by initially taking demineralized water in a beaker, slowly introducing the powder and then treating the mixture for one hour with an Ultra-Turrax which was set to the highest speed. The aqueous solution of the precondensate was then filtered over a fluted filter. 3.5 g of formic acid (100% strength) and 100 l of a fluorine-substituted surface-active agent (Zonyl FS 300, DuPont) were added to 30 g of this solution and the mixture was stored for 6 minutes at a temperature of 70 C. in a drying oven.

Example 1

(2) A part of preparation solution 1 was applied with the aid of a 0.2 knifecoater to one side of a 23.8 cm25.7 cm piece of kitchen roll (TORK (Premium) kitchen roll) having a basis weight of 53 g/m.sup.2. The amount of resin which was applied was 37%, based on dry kitchen roll. In order to prevent the cloth from tearing, it was underlaid with a protective paper. The coated material was then placed on an aluminum plate and dried for 15 min at 60 C. and 90% relative humidity in a conditioning chamber. The cloth coated with the preparation solution 1 was then stored for 15 min at 70 C. in a drying oven. Thereafter, the paper was dry and crosslinked. It had a basis weight of 73 g/m.sup.2.

Example 2

(3) A 34.3 cm24.1 cm sample of a paper having a basis weight of 36 g/m.sup.2 (TORK (Universal) Wiper 320 laboratory roll) was coated on one side with preparation solution 1, dried and crosslinked by the method stated in example 1. The amount of resin applied to the underlay was 26%. The basis weight of the coated substrate was then 45 g/m.sup.2.

Example 3

(4) Preparation solution 1 was sprayed onto one side of a 34.3 cm24.1 cm sample of a paper having a basis weight of 53 g/m.sup.2 (TORK (Universal) Wiper 320 laboratory roll). The applied amount of resin was 25%, based on dry paper. The coated sample was dried and crosslinked as stated in example 1. The basis weight of this sample was 66 g/m.sup.2.

Example 4

(5) Preparation solution 1 was sprayed onto both sides of a 34.3 cm24.1 cm sample of a paper having a basis weight of 53 g/m.sup.2 (TORK (Universal) Wiper 320 laboratory roll). The amount of resin applied altogether was 51%, based on uncoated paper. The coated sample was dried and crosslinked as stated in example 1. The basis weight of the sample was then 80 g/m.sup.2.

Example 5

(6) A black paper having a basis weight of 80 g/m.sup.2 was coated, dried and crosslinked by the method stated in example 1. The amount of resin applied to the paper was 35%, based on uncoated, dry paper. The surface of the paper was uniformly coated, without visible striae comprising resin. The coated, dried and crosslinked paper had a basis weight of 108 g/m.sup.2.

Example 6

(7) A paper having the dimensions 22.0 cm16.3 cm (Legamaster eraser sheet (board cloth)) and a basis weight of 47 g/m.sup.2 was coated, dried and crosslinked as stated in example 1. The amount of resin which was applied to the paper was 67%, based on uncoated, dry paper. The basis weight of the sample thus treated was 79 g/m.sup.2.

Example 7

(8) A paper having the dimensions 22.0 cm16.3 cm (Legamaster eraser sheet (board cloth)) and a basis weight of 47 g/m.sup.2 was sprayed on both sides with preparation solution 1, dried and crosslinked as described in example 4. The amount of resin applied altogether was 27%, based on uncoated, dry paper. The basis weight of the sample thus treated was 60 g/m.sup.2.

(9) The coated papers obtained according to the examples were tested for their suitability as wiping cloths and compared with commercially available, uncoated papers. For this purpose, the sample to be tested was fixed in each case to one side of a cylindrical punch having a diameter of 13 mm and a weight of 600 g with the aid of an adhesive. A panel having a surface comprising a melamine/formaldehyde resin (Resopal) was fastened on a mechanical shaker. The surface of the panel was then soiled with a permanent marker (Permanent Marker Eding 3000). The cylindrical punch was placed on this surface, that side of the punch which was adhesively bonded to the sample to be tested resting in each case on the Resopal panel. That part of the panel which was to be cleaned was moistened with 0.5 ml of demineralized water. The mechanical shaker operated with 20 double strokes/min with a horizontal panel deflection of 5 cm. When no cleaning of the panel was achieved after 40 strokes (removal of the marks on the panel) a new sample was adhesively bonded to the cylindrical punch and the test was continued therewith. The tests carried out and results obtained are shown in the table below.

(10) TABLE-US-00001 TABLE Cleaning cloth produced according to Mean value of number of strokes Example 3 95 Example 4 75 Comparative examples Comparison 1: >200 Uncoated paper according to Example 3 (TORK (Premium) kitchen roll) Comparison 2: >200 Commercial eraser tissues

(11) The Resopal panel was coated with Alpine Weiss and soiled with a wax crayon. Tests were then carried out with the following cleaning cloths:

(12) TABLE-US-00002 Cleaning cloth produced according to Mean value of number of strokes Example 3 28 Example 4 30 Comparative examples Comparison 1: No cleaning effect; the paper Uncoated paper according to Example 3 underwent defibration (TORK (Premium) kitchen roll) during the test Comparison 2: 65 Commercial eraser tissues