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Hydrophobic coating

A technology for hydrophobic coatings and coatings, applied in the direction of coatings, etc., which can solve the problems of poor self-cleaning contact angle, low characteristic sliding angle, and difficult to manufacture compositions.

Inactive Publication Date: 2015-06-24
UNILEVER NV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] While hydrophobic, especially superhydrophobic surfaces are desirable, the compositions that produce such surfaces are difficult to manufacture and may result in surfaces that exhibit poor self-cleaning—due to, for example, their characteristic contact angle being too low and / or their characteristic A direct consequence of too high a sliding angle
Furthermore, no reliable method for generating superhydrophobic coatings that do not alter the appearance of the treated surface is given

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0117] This example demonstrates the formulation of the hard surface treatment composition of the present invention.

[0118] Preparation of sol concentrate

[0119] 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, which was further stirred for 30 minutes to ensure uniform dispersion. Then 1.70 g of aqueous ammonia solution was slowly added to the mixture with constant stirring for 30 minutes. Then 15.996 grams of water were added and stirring was continued for 2 hours. 4.68 grams of hydrochloric acid was added slowly, followed by an additional 1.62 grams of DTS. The whole mixture was then stirred for a further 2 hours. The final pH of the composition was 2.18.

[0120] Preparation of hard surface preparation products

[0121] Dilute 190 g...

Embodiment 2

[0130] This example demonstrates the formulation of compositions of the invention with various amounts of silane.

[0131] Preparation of the composition

[0132] This composition was prepared in a similar manner to the sol concentrate described in Example 1. For all samples, the pH after addition of ammonium hydroxide was 10.7-10.9 and the pH after addition of hydrochloric acid was 0.5-0.9. Table 2 summarizes the samples tested.

[0133]

[0134] *Amount is the amount of 25 wt% aqueous solution

[0135] **Amount is the amount of 38 wt% aqueous solution.

[0136] Coating Preparation and Characterization

[0137] Contact angles and sliding angles were determined as in Example 1.

[0138] result

[0139] All compositions formed clear coats. The values ​​of contact angle and sliding angle are listed in Table 3 together with 95% confidence intervals.

[0140]

[0141] All samples produced hydrophobic coatings, whether judged by contact angle or sliding angle. ...

Embodiment 3

[0143] This example demonstrates the formulation of compositions of the invention with various amounts of hydrophobic silanes.

[0144] Preparation of the composition

[0145] This composition was prepared in the same manner as described in Example 2. Table 4 summarizes the samples tested.

[0146]

[0147] *Amount is the amount of 25 wt% aqueous solution

[0148] **Amount is the amount of 38 wt% aqueous solution.

[0149] Coating Preparation and Characterization

[0150] Contact angles and sliding angles were determined as in Example 1.

[0151] result

[0152] All compositions formed clear coats except Samples 15 and 16 where some oil spots were observed. The values ​​of contact angle and sliding angle are listed in Table 5 together with 95% confidence intervals.

[0153]

[0154] All samples yielded hydrophobic coatings, as judged by contact angle alone. However, only samples 11, 12 and 13 produced significantly hydrophobic coatings, as judged by the sli...

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Abstract

Disclosed is a process for manufacturing a coating composition, wherein the process comprises the steps of: (i) forming a reaction mixture comprising water, first quatemary silane and second quatemary silane, wherein the first quatemary silane has formula (I), Si(R1)4 (I) wherein each R is independently selected from alkoxy and halogen; and the second quatemary silane has formula (II), (R1)4 -m Si(R2)m (II) wherein each R1 is independently selected from alkoxy and halogen; R2 comprises at least 2 carbon atoms and is selected from alkyl, alkenyl, fluoroalkyl, fluoroalkenyl, aryl, fluoroaryl and combinations thereof; and m is an integer from 1 to 3; (ii) hydrolyzing the reaction mixture under basic conditions; and then (iii) continuing the hydrolysis under acidic conditions.

Description

field of invention [0001] The present invention relates to the manufacture of compositions for application to surfaces to produce hydrophobic coatings thereon. The invention relates in particular to such compositions comprising hydrolyzed silanes. Background of the invention [0002] Drought, poor irrigation and inadequate plumbing systems are just some of the reasons for water shortages in some areas. Water scarcity can cause serious social problems, such as health problems, as a direct consequence of inadequate cleaning applications when sufficient water is not available. [0003] Efforts have been made to clean surfaces with limited amounts of water. In fact, surface cleaning has been studied in an attempt to mimic the surface of a lotus leaf. For example, taro leaves have been used as templates for polystyrene structures that can exhibit the lotus leaf effect. This structure can be used for coatings with superhydrophobic properties. Articles with poorly wetted surfa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09D183/02C08G77/02C09D183/04
CPCC09D183/04C08G77/02C08G77/24C09D183/02
Inventor 李金勇陶庆胜
Owner UNILEVER NV