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Aqueous compositions for forming hydrophobic coatings

A hydrophobic coating and composition technology, applied in the direction of coating, etc., can solve the problems of low characteristic contact angle, difficult to manufacture composition, poor self-cleaning surface, etc.

Active Publication Date: 2018-05-04
UNILEVER IP HLDG BV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Although hydrophobic, and especially superhydrophobic surfaces are desirable, the compositions leading to such surfaces can be difficult to manufacture and they can lead to surfaces that exhibit poor self-cleaning, for example, as a direct consequence of their Feature contact angles are too low and / or their feature sliding angles are too high
Furthermore, a reliable method for generating superhydrophobic coatings that does not alter the appearance of the treated surface is unknown

Method used

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  • Aqueous compositions for forming hydrophobic coatings
  • Aqueous compositions for forming hydrophobic coatings

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0113] This example demonstrates the formulation of a hard surface treatment composition according to the invention.

[0114] Preparation of sol concentrate

[0115] A mixture of 489.10 g of ethanol and 35.19 g of TEOS (tetraethylorthosilicate from Sinopharm Chemical Reagent Co) was stirred at room temperature (25°C) for 30 minutes. Then 2.377 g of DTS (n-dodecyltrimethoxysilane from Tokyo Chemical Industry Co., Ltd) was added to the mixture and stirred for another 30 minutes to ensure uniform dispersion. Then, 1.70 g of aqueous ammonia solution was slowly added to the mixture and stirring was continued for 30 minutes. Then 15.996 g of water were added and stirring was continued for 2 hours. 4.68 g of hydrochloric acid were added slowly, followed by an additional 1.62 g of DTS. The whole mixture was then stirred for another 2 hours. The final pH of the composition was 2.18.

[0116] Preparation of hard surface preparation products

[0117] 190 g of the sol concentrat...

Embodiment 2

[0127] This example shows the effect of the order of the hydrolysis steps on the ability to form a uniform, clear composition.

[0128] Sol concentrates were prepared in a similar manner to the sol concentrates described in Example 1, except that for two samples (sample A and sample B) the acid hydrolysis step (with HCl) was performed before the alkaline hydrolysis step (with ammonia) . Table 2 summarizes the samples tested.

[0129] Table 2

[0130]

[0131] *Amount is the amount of 25 wt% aqueous solution.

[0132] **Amount is the amount of 38 wt% aqueous solution.

[0133] Both samples A and B were cloudy liquids with visible precipitates, and thus were not suitable for dilution with water to prepare clear, homogeneous compositions. In contrast, Sample 1 was homogeneous and transparent.

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Abstract

A method for making a coating composition is disclosed, wherein the method includes the steps of: (i) forming a reaction mixture comprising water and a first quaternary silane, wherein the first quaternary silane has formula (I), Si(R1 )4, wherein each R1 is independently selected from alkoxy and halogen; and (ii) hydrolyze the reaction mixture under basic conditions; and then (iii) continue hydrolysis under acidic conditions; and then (iv) use an aqueous liquid The reaction mixture is diluted to produce a coating composition containing at least 50 wt% water of the coating composition.

Description

technical field [0001] The present invention relates to the manufacture of compositions for application to surfaces to produce hydrophobic coatings thereon. In particular, the present invention relates to such compositions based on water and comprising hydrolyzed silanes. Background technique [0002] Drought, poor irrigation and inadequate plumbing are only some of the reasons for water shortages in some areas. Water scarcity can create serious social problems, such as health problems, as a direct result of inadequate sanitation applications where sufficient quantities of water are not present. [0003] Efforts have been made to clean surfaces with limited quantities of water. In fact, the cleaning of surfaces attempting to mimic the surface of a lotus leaf has been studied. For example, taro leaves have been used as templates for polystyrene structures, which can exhibit the lotus leaf effect. Such structures can be used for coatings with superhydrophobic properties. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09D183/02C08G77/02
CPCC09D183/02C08G77/02
Inventor 李金勇陶庆胜
Owner UNILEVER IP HLDG BV