SCREEN-WASH LIQUID FOR A VEHICLE WINDSHIELD

Abstract

Liquid screen-wash for vehicle windscreen, comprising between 0.01% and 10% by weight of a surfactant or of a mixture of surfactants, between 5% and 15% by weight of a glycol ether, and water.

Claims

1. A semen-wash liquid for the windshield of a vehicle, comprising: between 0.01 and 10% by weight of a surfactant or of a mixture of surfactants; between 5 and 15% by weight of a glycol ether; and water.

2. The screen-wash liquid as claimed in claim 1, wherein the glycol ether is butyl glycol.

3. The screen-wash liquid as claimed in claim 1, further comprising a mixture of an anionic surfactant and of a nonionic surfactant.

4. The screen-wash liquid as claimed in claim 1, further comprising between 0.05 and 1% by weight of one selected from a group consisting of: ammonia, sodium hydroxide or potassium hydroxide.

5. The screen-wash liquid as claimed in claim 1, wherein the liquid has a pH of between 9.5 and 9.8.

6. The screen-wash liquid as claimed in claim 1, further comprising between 0.01 and 1% by weight of at least one fragrance.

7. The screen-wash liquid as claimed in claim 1, further comprising between 0.01 and 1% by weight of at least one colorant.

8. The screen-wash liquid as claimed in claim 1, further comprising an alcohol ethoxylate, at between 0.01 and 5% by weight, and/or sodium lauryl sulfate, at between 0.01 and 1% by weight.

9. The screen-wash liquid as claimed in claim 1, wherein the surfactant or the mixture of surfactants has an HLB of between 12 and 14.

10. The screen-wash liquid as claimed in claim 1, wherein the surfactant or the mixture of surfactants has a CMC of between 6×10.sup.−3 and 8×10.sup.−3 mol.Math.L.sup.−1.

11. The screen-wash liquid as claimed in claim 1, further comprising dipropylene glycol monomethyl ether, at between 0.1 and 5% by weight.

12. The screen-wash liquid as claimed in claim 1, further comprising between 5 and 10% by weight of isopropanol.

13. The screen-wash liquid as claimed in claim 1, wherein the liquid has between 70 and 80% by weight of water.

14. The use of the screen-wash liquid as claimed in claim 1, for washing the windshield of a vehicle.

15. A method for washing the windshield of a vehicle using a windshield-wiper system of this vehicle, comprising: spraying screen-wash liquid as claimed in claim 1 onto the windshield; sweeping the windshield using at least one blade of the windshield-wiper system so as to spread the liquid over the windshield; spraying rinsing liquid onto the windshield; and sweeping the windshield using said at least one blade, wherein each of the steps of spraying and sweeping is followed by a waiting step during which said at least one blade remains immobile.

Description

DETAILED DESCRIPTION

[0035] The invention will be better understood and other details, characteristics and advantages of the invention will emerge on reading the following description comprising nonlimiting examples of formulation of the screen-wash liquid according to the invention.

Example 1: Composition of a Screen-Wash Liquid According to the Invention

[0036]

TABLE-US-00001 Compounds Mass percentages Butyl glycol  5-15 DPGME 0-5 Alcohol ethoxylate (Tergitol ® 15-s-7) 0-5 Sodium lauryl sulfate 0.01-0.1  Water 70-80 Isopropanol  5-10 S-Limonene 0-5 Sodium sulfite 0.1-1.sup. 

Example 2: Results of Tests Performed after Spraying Screen-Wash Liquids According to the Invention onto a Windshield

[0037] θ represents the contact angle of the screen-wash liquid on the windshield and thus reflects the wetting and spreading power of the liquid. The lower the contact angle, the better the spreading.

[0038] Four formulations (BG1 to BG4) of screen-wash liquid according to the invention were tested (these formulations comprising mass percentages of nonionic surfactant of between 0 and 2.5% and mass percentages of glycol ether of between 5 and 10%). Three contact angle measurements were taken following the deposition of a liquid onto, respectively, a clean windshield, a windshield covered with egg (protein) and a windshield comprising insect impacts. The pH of the various liquid formulations was also measured.

TABLE-US-00002 θ Clean θ Wind- θ Wind- wind- shield + shield + Formulations shield egg insects pH BG1 (5% glycol ether) 5 24 26 9.7 BG2 (5% glycol ether) 5 29 27 8.7 BG3 (10% glycol ether) 8 33 17 8.7 BG4 (5% glycol ether) 5 23 25 9.4

[0039] The results show that the presence of glycol ether in relatively high concentration in the liquid makes it possible to obtain relatively low contact angles θ on a clean windshield, which was expected due to the high wetting power of the glycol ether.

[0040] They also show that formulations BG1 and BG4 have a higher pH than the other formulations (BG2 and BG3), which has a positive effect on the dissolution of proteins (egg) and on the spreading of the screen-wash liquid (reduction of the contact angle θ).

[0041] The results also show that the glycol ether has a positive effect on the dissolution of insect impacts, since the contact angle obtained with formulation BG3 (comprising 10% glycol ether) is lower than those obtained with the other formulations (comprising 5% glycol ether).