Water based VOC free and biodegradable auto glass cleaner

Abstract

The present invention relates to a novel cleaning composition with low VOC contents and the method of making the same, the composition comprising: at least one water-soluble, non-toxic, and biodegradable organic cleaning solvent; a buffering system to maintain pH of the composition beteween 4 to 5; at least one biodegradable non-ionic surfactant; and DI water.

Description

[0001] DI83922

[0002] WATER BASED VOC FREE AND BIODEGRADABLE AUTO GLASS CLEANER

[0003] Aerosol cleaners are widely used as automotive glass cleaners. The current regulatory volatile organic compounds (“VOC”) limit for the aerosol cleaners has recently been reduced to 3% only. Due to this change, there is a need to have an automotive glass cleaner containing reduced VOC causing ingredients. While various ingredients have been tried in the past, it was difficult to design a water based, non-VOC composition that environmentally friendly, i.e. bio-degradable, and in the meantime remains stable during storage. The present invention provides such a new glass cleaner by including in the composition a stable buffer system that was created by using a certain concentration of acetic acid to stabilize the cleaner composition. Therefore, the present invention not only solves the VOC limit issue, but also improves the performance of the cleaner on different glass surfaces.

[0004] Summary of the Invention

[0005] This invention provides a cleaner composition having a) at least one water soluble, non-toxic and biodegradable organic cleaning solvent; b) a buffer system to maintain pH of the composition between 4 to 5; c) at least one biodegradable non-ionic surfactant; and d) DI water.

[0006] In a preferred embodiment, the present invention provides a cleaner composition comprising a) about 8 wt.% of dimethyl carbonate; b) about 0.0018 wt. % of a buffer comprising acetic acid and sodium acetate; c) about 0.05 wt.% of a non-ionic surfactant comprising seed oil and alcohol ethoxylate; and d) about 90 wt.% of DI water, all based on the total weight of the composition.

[0007] Detailed Description of the Invention

[0008] The present glass cleaner composition includes the following ingredients.DI83922

[0009] A. At least one water soluble, non-toxic and biodegradable organic cleaning solvent.

[0010] Many different solvents can be used in the present invention. Such solvents may include, alone or in combination with others, acetone, methyl acetate, tertiary butyl acetate, propylene carbonate, para-chlorobenzotrifluoride, propylene carbonate, 2-amino-2-methyl-l-propanol (AMP) and dimethyl carbonate. In a preferred embodiment of the present invention, dimethyl carbonate is used as such a solvent. However, solvents such as dimethyl carbonate tend to hydrolyze if the solution is not buffered properly.

[0011] The cleaner composition may comprise 5-20 wt.%, preferably 6-15 wt.%, more preferably 8-13 wt.% and most preferably 8-9 wt.% of the cleaner composition. In a preferred embodiment, the cleaner composition has around 8 wt.% of dimethyl carbonate.

[0012] B. A buffer system

[0013] A buffer system in the composition is very critical in preventing the hydrolyzation of the solvents. Many different chemicals may be used to create a buffer system in an acidic environment. These may include non-volatile buffers such as citric acid, lactic acid, formic acid, succinic acid, acetic acid, methyl malonic acid, and their respective salts. The preferred embodiment of the present composition has a buffer system comprising acetic acid and its related salts. For example, in a preferred embodiment, the present buffer system comprises 0.1-0.25 wt.% of acetic acid and 0.5-0.9 wt.% of sodium acetate, based on the total weight of the buffer system. Acetic acid containing buffer system creates a properly buffered week acid composition environment and it can maintain the stability of the solvent used and add additional cleaning properties to the composition.

[0014] To achieve the intended purpose, the buffer system should maintain the composition at pH about 4-5 with about 4.5 being the desired and preferred pH level. The cleaner composition of the present invention may contain 0.0015 to 0.0025 wt. %, preferably 0.0016 to 0.0020 wt. % and more preferably 0.0017 toDI83922

[0015] 0.0019 wt. %, and most preferably about 0.0018 wt. % of the buffer system.

[0016] C. Biodegradable non-ionic surfactants

[0017] The present composition further comprises at least one biodegradable nonionic surfactant. The surfactant is used to reduce the surface tension of other ingredients of the composition, including DI water. The inclusion of at least one non-ionic surfactant helps the removal of oil, grease, or other contaminants the present composition is intended to clean. Many different biodegradable non-ionic surfactants may be considered, and among which include amine oxides, fatty acid ester (e.g. fatty acids derived from coconut oil and polyethylene glycol), alkyl polyglucosides etc. In a preferred embodiment, seed oil and alcohol ethoxylate containing surfactant, commercially available as EcoSurf SA-7 from Dow Inc, is used. The non-ionic surfactant typically is typically used at about 0.01 to 2 wt.%, preferably 0.015 to 1.8 wt. %, and more preferably 0.02 to 1.5 wt.% of the composition,

[0018] In some applications, the ionic surfactant may also be considered but in all preferred embodiments, the present invention uses non-ionic surfactants in its compositions due to its excellent wetting performance, lower environmental impact and less toxicity.

[0019] D. Other ingredients

[0020] DI water constitutes the vast majority of the rest of the composition of the present invention. A typical composition will comprise about 85-95 wt.% of DI water, based on the total weight of the composition.

[0021] The composition may also include other ingredients: e.g. anti-freezing agent such as ethylene glycol, and coloring agents etc. The amounts of these other ingredients can vary based on different applications.

[0022] Examples and TestingDI83922

[0023] To further illustrate the present invention, an inventive example was prepared with their relative compositions as listed in Table 1. The example was prepared by simply mixing all the raw ingredient materials in Table 1 in room temperature. The material tradenames, if applicable, and their sources are also included in Table 1.

[0024] Table 1. Composition details of the inventive example

[0025]

[0026] This inventive example was used to compare with some critical properties of a prior commercially available cleaning composition (“comparative example”) with high VOC contents. This prior composition is under the tradename Burco. As a comparison, the comparative example, Burco example has the following ingredients:

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[0031] ethyl alcohol (ethanol) <= 1,0

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[0035] Adhesion performance of the inventive and comparative examples, after different open times, were evaluated for Lap Shear adhesion tests with different glass coupons.

[0036] Lap Shear was measured using Instron 5500R type Tensile Tester; Glass coupon size: 25.4*102 mm at a nominal thickness of 5.5 mm, Adhesive layer thickness 5mm, Curing condition: Room Temperature, 3 days, samples were tested with a pull rate of 50.8mm / min.

[0037] pH was measured using Calibrated Mettler Toledo T9 pH titrator. Sample Size: 50mL.

[0038] Stability Study was performed using a Calibrated Despatch Oven;

[0039] Temperature: 54°C.

[0040] The testing results for 3 days lap shear tests are summarized in Table 2. In the table, CF stands for Cohesive Failure, AF stands for Adhesion Failure and CF* refers to Thin Film Cohesive Failure.

[0041] Table 2: Three (3) days Initial La p S h ea r testi

[0042]

[0043]

[0044] DI83922

[0045]

[0046] Tests for adhesion performance of the comparative and inventive examples were performed on basis of Lap Shear tests as described above. Testing for adhesion was performed on different glass coupons as identified in Table 2. These glass coupons are standard from most OEM specifications.

[0047] After 3 days of room temperature curing, the adhesion performance of samples prepared with inventive example showed significantly better performances than the samples prepared with comparative example. The inventive samples passed the adhesion testing with an average cohesive failure mode of 100%. Such results prove the better wetting and cleaning performance of the inventive examples compared to the comparative samples.

[0048] The inventive example is also tested for its pH stability at different temperatures between the room temperature, ~ 20°C, to 54°C and 1, 5, 10, and 15-day intervals. The pH tests were conducted following ASTM E70-24. The results indicate that the pH of the present compositions stayed between 3.5-6.5 under all these testing environments. Some of the pH testing results of the preferred embodiments of the present invention are shown in Table 3.DI83922

[0049] Table 3. pH stability test results of the Inventive Example

[0050]

[0051] Table 3 indicates that the present composition achieved pH stability under different testing conditions and overtime. The comparative example’s pH was reported in the SDS as, in between 4.5-5.5 range.

Claims

DI83922WHAT IS CLAIMED IS:

1. A cleaner composition comprising a) at least one water soluble, nontoxic and biodegradable organic cleaning solvent; b) a buffer system to maintain pH of the composition between 4 to 5; c) at least one biodegradable non-ionic surfactant; and d) DI water.

2. The cleaner composition of Claim 1, wherein the organic cleaning solvent is one selected from acetone, methyl acetate, tertiary butyl acetate, propylene carbonate, para-chlorobenzotrifhioride, propylene carbonate, 2-amino-2-methyl-l-propanol (AMP), dimethyl carbonate or a mixture thereof.

3. The cleaner composition of Claim 2, wherein the organic cleaning solvent comprises dimethyl carbonate.

4. The cleaner composition of any one of the preceding claims comprising 5-20 wt.% of the organic cleaning solvent, based on the total weight of the cleaner composition.

5. The cleaner composition of any one of the preceding claims comprising about 8 wt.% of dimethyl carbonate, based on the total weight of the cleaner composition.

6. The cleaner composition of any one of the preceding claims wherein the buffer system comprises at least one of citric acid, lactic acid, formic acid, succinic acid, acetic acid, methyl malonic acid, and their respective salts.

7. The cleaner composition of Claim 6, wherein the buffer system comprises acetic acid and sodium acetate.DI839228. The cleaner composition of Claim 7 comprising 0.1 to 0.25 wt.% of acetic acid and 0.5 to 0.9 wt.% of sodium acetate, based on the total weight of the buffer system.

9. The cleaner composition of any one of the preceding claims wherein the composition comprises 0.0015 to 0.0025 wt. of the buffer system.

10. The cleaner composition of any one of the preceding claims wherein the at least one biodegradable non-ionic surfactant is selected from amine oxides, fatty acid ester, alkyl poly glucosides, seed oil, alcohol ethoxylate, or a mixture thereof.

11. The cleaner composition of Claim 10, wherein the fatty acids are derived from coconut oil and polyethylene glycol.

12. The cleaner composition of Claim 10, where in the non-ionic surfactant comprised seed oil and alcohol ethoxylate.

13. The cleaner composition of any one of the preceding claims wherein the composition comprises about 0.01 to 2 wt.% of the non-ionic surfactant, based on the total weight of the composition.

14. The cleaner composition of any one of the preceding claims wherein the composition comprises 85 to 95 wt.% of DI water, based on the total weight of the composition.

15. A cleaner composition comprising a) about 8 wt.% of dimethyl carbonate; b) about 0.0018 wt. % of a buffer comprising acetic acid and sodium acetate; c) about 0.05 wt.% of a non-ionic surfactant comprising seed oil and alcohol ethoxylate; and d) about 90 wt.% of DI water, all based on the totalDI83922weight of the composition.

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