Method for removing dirt deposits from headlights

Abstract

A method for restoring headlights in which the protective coating is neither removed nor altered. Therefore, the German Road Traffic Regulations (StVZO) are not affected.

Description

[0001] Since the 1990s, car headlights have no longer been made of glass, but of polycarbonate. This material has the disadvantage – besides various advantages – of not being UV-stable. Therefore, a protective coating is applied that converts the UV rays into IR rays (heat).

[0002] Over the years, the coated surface can suffer minor damage from sand, impact debris, hail, salt, or even improper cleaning agents. Dirt and fine dust—consisting of, for example, rubber and brake pad abrasion, soot, oil, exhaust fumes, pollen, insects, and salt—accumulate in these microcraters. This layer of dirt has negative consequences for safety in the dark, as headlights damaged in this way lose brightness and can also dazzle other road users due to altered light distribution.

[0003] The most common method for headlight restoration on the market involves the abrasive removal of the entire protective layer using various abrasives. Subsequently, various products are applied to restore the protection, but their effectiveness is highly questionable.

[0004] This method constitutes a "structural modification" as defined by the German Road Traffic Regulations (StVZO), which is generally not permitted. Currently, in the absence of an alternative to the costly replacement of the headlights, refurbishing them remains the only practical option.

[0005] The content of this invention is a method for restoring headlights in which the protective coating is neither removed nor altered. The German Road Traffic Regulations (StVZO) are therefore not affected.

[0006] A cleaning agent that completely removes the dirt buildup, even from the aforementioned micro-craters, restores the headlight's full functionality without the need for abrasive removal (by sanding the surface with abrasives). Apply the liquid cleaning agent to an absorbent, flexible material such as a cotton cloth, fleece, or paper towel, and wipe the surface with light pressure, possibly several times. It is advisable to repeat the procedure if necessary. State of the art:

[0007] In the patent specification (1) WO 2018 / 165007 A1

[0008] Two cleaning units, which complement each other with different effects for removing dirt deposits from headlights, are listed. Almost the entire range of organic chemicals is mentioned as a source of components. Furthermore, to achieve successful cleaning, considerable pressure must be applied to the cloth soaked with these cleaners.

[0009] In patent specification (2) US 2013 / 0 015 160 A1

[0010] A cleaner is presented that also contains a wealth of different components of organic chemistry.

[0011] The content of this invention is a method for restoring headlights in which the protective coating is neither removed nor altered. The German Road Traffic Regulations (StVZO) are therefore not affected.

[0012] One product group was surprisingly discovered to be an excellent cleaner for removing the adhering dirt deposits on headlights.

[0013] This product group is widely used as plasticizers for a range of plastics, such as PVC. It consists of phthalic acid esters of the general formula phthalic acid dialkyl or dicycloalkyl esters, where the alkyl chain has the formula CnH2n+1 (n=1 to 11) and the cycloalkyl chain the formula CnH2n-1 (n=5-11), and phthalic acid alkyl aryl esters, where the alkyl part corresponds to the formula CnH2n+1 (n=1 to 11) and the aryl part to the formula CnH2n-1 (n=6).

[0014] Other products or product groups that were also discovered to be excellent cleaners for removing adhering dirt deposits from headlights.

[0015] Specifically, they are: Maleinates, succinates or butenedioates, glutarates, adipates, citrates and terephthalates e.g. B. Dibutyl maleinate (DBM), dimethyl succinate, dimethyl glutarate, bis (2-ethylhexy) adipate (DEHA), diisononyl adipate (DiNA), acetyl tributyl citrate (ATBC) and di (2-ethylhexyl) terephthalate (DEHTP),

[0016] Further: 1,2-Cyclohexanedicarboxylic acid diisononyl ester (DINCH), diethylene glycol dibenzoate and tri-(2-ethylhexy)trimellitate (TEHTM) Only these products are able to completely remove the dirt without damaging the protective coating. Due to the higher viscosity of some of the above-mentioned products, it is advisable to thin them, as is usual with paints, so that better results can be achieved through easier application.

[0017] Several solvent groups are suitable for reducing viscosity.

[0018] The first group comprises aliphatic hydrocarbons under the general name test gasoline.

[0019] The second group includes aromatic hydrocarbons, such as toluene and xylene.

[0020] Another group comprises aliphatic carboxylic acid esters, in particular a series of acetic acid esters of the general formula CH3COO-alkyl, where the alkyl group is CnH2n+1 (n=1-5).

[0021] The last group consists of aliphatic ketones, such as acetone, methyl butyl ketone and cyclophexanone.

[0022] In particular, the last two groups are well suited as thinning agents because only small amounts are needed to achieve a lower viscosity.

[0023] In contrast to the two cleaners listed in patent specifications (1) and (2), the cleaner presented here consists of only 1 or 2 components: Example 1:

[0024] Dimethyl phthalate (DMP) is a phthalate with the lowest viscosity in its group. It can function as a cleaner without the addition of a thinner. Example 2:

[0025] A mixture consisting of 20% by volume white spirit and 80% by volume diisopropyl phthalate (DiPP) Example 3:

[0026] A mixture consisting of 10 vol. % n-pentyl acetate and 90 vol. % diethylhexyl phthalate (DEHP) - the most widely used plasticizer for PVC (annual production approx. 6 million tons) - is interesting due to its availability and extremely low price. Example 4:

[0027] A mixture consisting of 10% acetone and 90% diisononyl phthalate (DINP) Example 5:

[0028] A mixture consisting of 5% acetone, 5% ethyl acetate and 90% bis(2-propylheptyl) phthalate (DPHP) Example 6:

[0029] A mixture consisting of 10 vol. % ethyl acetate and 90 vol. % dibutyl maleate (DBM). Example 7:

[0030] A mixture consisting of 25 vol. % white spirit and 75 vol. % bis(2-ethylhexyl)adipate(DEHA). Example 8:

[0031] A mixture consisting of 30 vol. % white spirit and 70 vol. % di(2-ethylhexyl)terephthalate (DEHTP). Example 9:

[0032] A mixture consisting of 10 vol. % white spirit and 90 vol. % 1,2 cyclohexanedicarboxylic acid diisononyl ester (DINCH). Example 10:

[0033] A mixture consisting of 15% by volume white spirit and 85% by volume diethylene glycol dibenzoate. Example 11:

[0034] A mixture consisting of 10 vol. % ethyl acetate and 90 vol. % tri-(2-ethylhexy)trimellitate (TEHTM). The cleaner is also easy to use:

[0035] A thin fleece or cotton cloth (approx. 15 x 15 cm) is crumpled in the hand. 3-4 ml of the cleaner is applied to it. The cloth is then kneaded in the hand to distribute the cleaner more evenly.

[0036] It's even easier if you fold a sheet of kitchen paper into a handy little packet and add the cleaner drop by drop as needed.

[0037] The dirt coating on the headlights is completely removed using a damp fleece, cotton cloth or a folded sheet of kitchen paper, applying no pressure with wiping motions.

[0038] Other compounds such as chlorinated and nitrated (aliphatic and aromatic hydrocarbons) as well as O- and N-heterocycles and their carboxylic acid esters do have a cleaning effect, but attack the protective layer, making them unsuitable for this purpose. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2018 / 165007 A1

[0007] US 2013 / 0 015 160 A1

[0009]

Claims

[1] A cleaning agent consisting of a mixture of the following two liquid components of selection: one component from the group of phthalates of the formula C8H4O4-dialkyl, wherein alkyl-CnH2n+1 (n= 1 to 11) or dicycloalkyl, wherein cycloalkyl-CnH2n-1 (5 to 11) and phthalic acid alkyl aryl esters, wherein the alkyl part has the formula CnH2n+1 (n=1 to 11), and the aryl part has the formula CnH2n-1 (n=6) and the other from the group of aliphatic hydrocarbons (HC) C4-C14, aromatic HC C7-C8 or alkyl acetates CH3COO-alkyl of the formula nH2n+1 (n= 1-8), or from ketones such as acetone, methyl butyl ketone and cycloexyl ketone. [2] A cleaning agent consisting of a mixture of the following two liquid components of the selection; a component of the group of maleates of the formula C4H2O4-dialkyl, or a component of the group of succinates of the formula C4H4O4-dialkyl, or a component of the group of glutarates of the formula C5H6O4-dialkyl, or a component of the group of adipates of the formula C6H8O4-dialkyl, or a component of the group of citrates of the formula C6H5O7-dialkyl, and a component of the group of terephthalates of the formula C8H4O4-dialkyl, wherein alkyl- CnH2n+1 (n= 1 to 4) and the other correspond to the group of aliphatic hydrocarbons (HC) C4-C14, aromatic HC C7-C8 or alkyl acetates CH3COO-alkyl of the formula CnH2n+1 (n=1-8) or to ketones such as acetone, methyl butyl ketone and cyclohexyl ketone. [3] A cleaning agent - cleaner - according to claim 1, consisting of 100% dimethyl phthalate (DMP). (Variant 1) [4] A cleaning agent - cleaner - according to claim 1, comprising a mixture of 10 vol. % n-pentyl acetate and 90 vol. % diethylhexyl phthalate (DEHP) (variant 2). [5] A cleaning agent - cleaner - according to claim 2, comprising a mixture of 10 vol.% ethyl acetate and 90 vol.% dibutyl maleate (DBM). (Variant 3) [6] A cleaning agent - cleaner - according to claim 2, comprising a mixture of 25 vol.% white spirit and 75 vol.% bis(2-ethylhexyl)adipate (DEHA). (Variant 4) [7] A cleaning agent - cleaner - according to claim 2, comprising a mixture of 30 vol.% white spirit and 70 vol.% di(2-ethylhexyl) terephthalate (DEHTP). (Variant 5) [8] A cleaning agent - cleaner - according to claim 2, comprising a mixture of 10 vol.% toluene and 90 vol.% 1,2-cyclohexanedicarboxylic acid diisononyl ester (DINCH). (Variant 6) [9] A cleaning agent - cleaner - according to claim 2, comprising a mixture of 15 vol.% white spirit and 85 vol.% diethylene glycol dibenzoate. (Variant 7) [10] A cleaning agent - cleaner - according to claim 2, comprising a mixture of 10 vol.% ethyl acetate and 90 vol.% tri-(2-ethylhexy)trimellitate (TEHTM). (Variant 8)