Strong absorptive dope of restraining frost

A strong water-absorbing, coating technology, applied in anti-fouling/underwater coatings, coatings, defrosting, etc., can solve problems such as unsatisfactory coating thickness, poor impact resistance, and inconspicuous anti-frost effect

Inactive Publication Date: 2007-02-21
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But it also has certain disadvantages, that is, the anti-frost effect is not obvious in the case of high ambient humidity.
When the ambient humidity is above 55%, the cold surface of the hydrophilic coating generally has initial frost crystals after about 25 minutes of refrigeration experiment, and the coating thickness is not ideal, generally above 0.3mm, and the coating is too thick It will increase the thermal resistance of the heat exchanger and reduce the heat transfer efficiency. In addition, the surface of the coating is relatively soft and has poor impact resistance.
Therefore, the hydrophilic coating still needs to be improved in terms of its film-forming thickness, surface hardness, anti-frost effect under high humidity conditions, etc.

Method used

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  • Strong absorptive dope of restraining frost
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  • Strong absorptive dope of restraining frost

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The production steps of anti-frost coating are as follows:

[0025] 1. Production of water-absorbent resin (refer to the general process of making water-absorbent resin):

[0026] The composition of the water-absorbing resin is as follows by mass: acrylic acid 49, acrylamide 10, water 160, potassium hydroxide 20, sodium hydroxide 5, hydroxypropyl methacrylate 7, N,N'-methylenebisacrylamide 0.002, initiation Agent (ammonium persulfate) 0.04, sodium bisulfite 0.05.

[0027] According to the above formula, add water, potassium hydroxide and sodium hydroxide into the reactor with reflux condenser, dropping funnel nitrogen conduit, and add acrylic acid and N,N'-methylenebispropylene under the condition of nitrogen gas. Amide, add hydroxypropyl methacrylate while stirring, and keep the temperature at 40°C. Add acrylamide, add ammonium persulfate initiator and sodium bisulfite in 4 times. It was heated to 60° C. and allowed to stand for 6 hours for polymerization reaction. The mix...

Embodiment 2

[0043] The composition of the water-absorbing resin is shown in Table 1, and the manufacturing process is the same as in Example 1. Weigh 20 grams of water-absorbent resin, 40 grams of polyurethane baking varnish, 30 grams of calcium chloride, and 30 grams of 200# gasoline. After mixing, stir thoroughly and spray the mixture on the inner wall of the refrigerator with a spray gun. Figure 7 A comparison of the amount of frost on the inner wall surface of the refrigerator coated with the strong water-absorbing frost-inhibiting paint of the present invention and the bare inner wall surface without any paint after the refrigerator has been operated for six months. The left side is the hydrophilic surface, and the right side is the bare surface of the inner wall of the refrigerator. The environmental conditions are T∞=-30.6°C, Tw=-34.0°C, and φ=80%. It can be seen from the picture that a thick layer of frost has formed on the bare surface of the inner wall of the refrigerator on the rig...

Embodiment 3,4

[0045] Table 1 lists the components of the anti-frost coating in Examples 3, 4, and 5 respectively. The production process and test equipment of the super absorbent resin and the anti-frost coating are the same as those in Example 1. The examples are also listed in Table 1. The components of 1, 2 and the test effects of 5 examples.

[0046] It is measured in the experiment that when the air humidity is less than 75%, the wall temperature is more than -20°C, and the ambient temperature is 20°C, the surface coated with the strong water-absorbing anti-frost coating of the present invention can keep the initial frost crystals at least After a delay of more than 3 hours, the frost suppression effect is quite obvious, as shown in Examples 1, 3, 4 and 5 in the table. In addition, the longest measurement time for the frost suppression experiment of the strong water-absorbent frost-inhibiting paint is six months. Using the actual running refrigerator as the experimental environment, the in...

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Abstract

This invention discloses a frost-inhibitive paint with good water absorbency, which comprises: polyacrylic acid absorbent resin 20-40 parts, metal baking paint containing polyacrylic acid resin, amino alkyd resin or polyurethane 40-60 parts, NaCl or KCl crystal particles 20-40 parts, and solvent 20-40 parts. The solvent is cyclohexanone, gasoline, propylene glycol butyl ether, butyl acetate or butanone. The layer painted from the paint has a thickness of 0.06 mm, and an impact strength higher than 50 kg .cm / cm2. The paint has a more obvious frost-inhibitive effect when the humidity is 50%.

Description

Technical field [0001] A strong water absorption anti-frost coating belongs to the technical field of refrigeration and energy saving. Background technique [0002] Frosting is a common phenomenon in nature. When a surface temperature is lower than the dew point temperature of water vapor in the air, frosting may occur. The existence of this phenomenon brings a lot of inconvenience to actual production and life, and the defrosting process will also consume a lot of energy, so it is necessary to explore various methods of frost suppression. One of the effective methods to suppress frost is to change the surface properties of the heat exchanger and apply hydrophilic coatings. [0003] The anti-frost mechanism of hydrophilic coatings is still under specific exploration, but it is generally believed that the hydrophilic coating contains strong water-absorbing substances, which can absorb the water droplets condensed on the surface of the cold plate to the coating system at the beginn...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09D133/02C09D5/16
CPCF25D21/04
Inventor 刘中良勾昱君孟声王洪燕王皆腾
Owner BEIJING UNIV OF TECH
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