JP2017210506A - Component having frost resistance, dew resistance, and icing resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a component for a low temperature environment with excellent slippery water repellency, having frost resistance, dew resistance, and icing resistance.SOLUTION: A component for low a temperature environment is obtained by forming a slippery water repellent layer on a base material. The slippery water repellent layer has a sea-island structure including a perfluoro structure and a siloxane structure. A height H showing a peak value of a frequency of a height distribution curve on a surface of the slippery water repellent layer is 11.8 nm or less.SELECTED DRAWING: None

Description

  The present invention relates to a low temperature environment member having a sliding water repellent layer formed on a substrate.

  Conventionally, there are many cases in which trouble occurs due to frost, dew, or ice on the surface of a member in winter when the atmospheric temperature is low, and many studies have been made to prevent frost, condensation, and icing.

For example, there is a risk that if the surface of the traffic signal is icing or snowing, the traffic signal becomes invisible. In particular, many traffic lights using LEDs have been installed, and the danger is increasing. Moreover, the transparency may be lost by frost, condensation, and icing on automobile windows and window glass, which is a problem. In outdoor units of air conditioners, heat exchangers of heat pump units, etc., since the surface temperature of the metal fins is below the dew point of the atmosphere, water droplets generated by condensation adhere to the surface of the metal fins, and heating operation In the outdoor unit at the time, since the atmospheric temperature is low, the water droplets on the fin surface freeze and become frozen, which increases the resistance to ventilation and reduces the air volume, resulting in a significant decrease in heat exchange efficiency. There is.
As a solution to such a problem, measures are taken to prevent frost, condensation and icing by processing the surface of the target member.

For example, Patent Document 1 discloses that the surface is super-water-repellent by applying a water-repellent coating composition composed of an organic resin solution and fine particles.
Patent Document 2 discloses that the surface is water-repellent with a coating film of organopolysiloxane and an organopolysiloxane having a silanol group.
Further, in Patent Document 3, the difference (hysteresis) between the advancing contact angle and the receding contact angle with respect to the liquid droplets on the surface is extremely small by the silicone homopolymer film, copolymer film, or amorphous fluororesin coating film. Is disclosed.

Japanese Patent Laid-Open No. 5-117737 JP 2002-323298 A Patent No. 5768233

  However, although the coating described in Patent Document 1 has been studied to make the surface super water-repellent and increase the frost formation time, the water repellency is still insufficient and there is a problem in durability.

  The film described in Patent Document 2 has a water-repellent surface with an organopolysiloxane and a coating film of an organopolysiloxane having a silanol group, but as in Patent Document 1, the water repellency is still not sufficient, In addition, since the oil repellency is low, a decrease in frosting function due to the surface adhesion of solid impurities inside the water droplets may be a problem.

  The film described in Patent Document 3 is a silicone homopolymer film, copolymer film, or amorphous fluororesin coating film, which has a surface with extremely small hysteresis, such as silicon, glass or quartz, and a surface of a practical metal or alloy. The present invention relates to a technique for modifying a solid surface that can improve the sliding property, water resistance, removability of a droplet from a solid surface, and anticorrosion properties. However, in the case of a silicone homopolymer film or copolymer film, the water repellency and oil repellency are still not sufficient as in Patent Document 2, so that the drop of the liquid drop due to adhesion of solid impurities inside the liquid droplet is a problem. It may become. In the case of an amorphous fluororesin, the adhesiveness to the solid surface is insufficient, and durability may be a problem in practical use. Furthermore, in any case of silicone homopolymer film, copolymer film, or amorphous fluororesin, heat treatment is necessary for the expression of the low hysteresis function. May not be applicable.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the sliding water-repellent layer has a sea-island structure containing a perfluoro structure and a siloxane structure, and the frequency of the height distribution curve on the surface of the sliding water-repellent layer. It was found that the sliding water repellency on the surface of the member can be improved when the height H indicating the peak value of the above is below a certain value.
Furthermore, since the sliding water-repellent layer is fixed through a covalent bond with a hydroxyl group which is an oxygen-containing polar group on the surface of the base material, it has also been found to have durability that can withstand practical use.
The present invention has been completed based on such findings.

That is, the present invention provides the following [1] to [9].
[1] A member formed by forming a sliding water-repellent layer on a substrate, the sliding water-repellent layer having a sea-island structure containing a perfluoro structure and a siloxane structure, A member for a low-temperature environment, wherein the height H indicating the peak value of the frequency of the height distribution curve is 11.8 nm or less.
[2] The member for low temperature environment according to [1], wherein the height distribution curve has one inflection point on a side lower than the height H indicating the peak value.
[3] A height H indicating the peak value of the height distribution curve, and a height H _{1 / 2L} on the lower elevation side of the height indicating 1/2 of the peak value of the height distribution curve, The member for low-temperature environment according to the above [1] or [2], which satisfies the relationship of the following formula (I).
H-H _{1 / 2L} ≦ 2.5nm (I)
[4] Height H _{1 /} indicating the peak value of the frequency of the height distribution curve and the height H _{1 /} on the higher elevation side among the heights indicating ½ of the peak value of the frequency of the height distribution curve. _The member for low-temperature environment according to any one of the above [1] to [3], wherein _2H satisfies the relationship of the following formula (II).
H _{1 / 2H} −H ≦ 3.0 nm (II)
[5] Height H _{1 /} indicating the peak value of the frequency of the height distribution curve, and the height H _{1 /} on the side where the altitude is lower among the heights indicating 1/3 of the peak value of the frequency of the height distribution curve. _The member for low-temperature environments according to any one of the above [1] to [4], wherein _3L satisfies the relationship of the following formula (III).
H-H _{1 / 3L} ≦ 3.0 nm (III)
[6] Height H _{1 /} indicating the peak value of the frequency of the height distribution curve, and the height H _{1 /} on the lower elevation side among the heights indicating 1/10 of the peak value of the frequency of the height distribution curve. _The member for low-temperature environments according to any one of the above [1] to [5], wherein _10L satisfies the relationship of the following formula (IV).
H-H _{1 / 10L} ≦ 10.0nm (IV)
[7] The member for low-temperature environment according to any one of [1] to [6], wherein a ratio of an island portion in the sea-island structure is 20 to 50%.
[8] The low-temperature environment member according to any one of [1] to [7], wherein the perfluoro structure and the siloxane structure are polycondensation products of alkoxysilanes having a perfluoropolyether structure.
[9] The low-temperature environment use as described in [8] above, wherein the polycondensation product of an alkoxysilane having a perfluoropolyether structure is a polycondensation product of an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane. Element.

  ADVANTAGE OF THE INVENTION According to this invention, the member for low temperature environments excellent in sliding-down water repellency can be provided.

6 is an AFM observation image of the surface of a sliding water-repellent layer of a member obtained in Reference Example 2. 3 is an AFM observation image of the surface of a sliding water-repellent layer of a member obtained in Comparative Example 1. 4 is a height distribution curve of a sliding water-repellent layer surface of Reference Example 1. 6 is a height distribution curve of a sliding water-repellent layer surface of Reference Example 2. 10 is a height distribution curve of a sliding water-repellent layer surface of Reference Example 3. 4 is a height distribution curve of a sliding water-repellent layer surface of Comparative Example 1. It is the schematic of the jig | tool used for evaluation of the icing property of the member for low temperature environments of this invention. (A) is a bird's-eye view of a jig | tool, (b) is a side view of a jig | tool. It is a side view explaining the sample used for evaluation of the icing property of the member for low temperature environments of this invention. It is a side view explaining the evaluation method of the icing property of the member for low temperature environments of this invention. It is an evaluation result of durability of the member for low-temperature environments of the present invention. It is the schematic explaining the coupling | bonding of the sliding water-repellent layer and base material of the member for low temperature environments of this invention.

First, the low temperature environment member of the present invention will be described.
The “low temperature” as used in the low temperature environment member of the present invention is a temperature range in which snowfall is possible and may be 5 ° C. or higher depending on the environment, but is generally 3 to 4 ° C. or lower.
<Low temperature environment components>
The member for low temperature environment of the present invention has a sliding water repellent layer formed on a substrate. The sliding water-repellent layer has a sea-island structure containing a perfluoro structure and a siloxane structure, and the height H indicating the peak value of the height distribution curve on the surface of the sliding water-repellent layer is 11.8 nm or less.

[Sliding water repellent layer]
The sliding water-repellent layer used in the low temperature environment member of the present invention is a layer having sliding water repellency, and has a sea-island structure.
Actually, when an AFM observation image was analyzed for the sliding water-repellent layer surface of the low-temperature environment member of the present invention, as shown in FIG. 1, the sliding water-repellent layer surface had a gentle wave shape (sea portion). The sea-island structure has discontinuous protrusions (island portions) having a diameter of about 200 to 1000 nm and a height of about 8 to 20 nm in the wave shape (sea portion).

The ratio of the island portion of the sea-island structure is preferably 20 to 50% from the viewpoint of exhibiting the effects of the present invention, more preferably 25 to 50%, and still more preferably 30 to 45%. .
The ratio of the island part of the sea-island structure is calculated by calculating the average value of the height data of the sliding water-repellent layer surface by measuring the shape of the sliding water-repellent layer surface with an atomic force microscope (AFM). The number of measurement points having a height equal to or higher than the value × 100 / the number of all measurements] is obtained by measuring 20 points and calculating the average of the measured 20 points.
However, data with a height of 25 nm or more was excluded from the calculation as foreign matter.

  The sliding water-repellent layer has a height H of 11.8 nm or less indicating the peak value of the frequency of the height distribution curve on the sliding water-repellent layer surface.

3 to 5 are height distribution curves in an arbitrarily selected region of 10 μm × 10 μm on the sliding water-repellent layer surface of Reference Examples 1 to 3. FIG. 3 to 5, “H” indicates a height indicating a peak value (frequency 100) of the frequency of the height distribution curve.
In the sliding water-repellent layer, the height H indicating the peak value of the frequency of the height distribution curve is 11.8 nm or less, preferably 11.0 nm or less, more preferably 10.5 nm or less, and still more preferably. Is 10.0 nm or less.
It can be said that the height H indicating the peak value of the frequency of the height distribution curve approximates the boundary between the sea portion and the island portion of the sea-island structure. That is, the height H indicating the peak value of the frequency of the height distribution curve is 11.8 nm or less indicates that the sea portion is uniform and shallow as in the AFM observation image of FIG. Therefore, the effect of the present invention can be exhibited by satisfying that the height H indicating the peak value of the frequency of the height distribution curve is 11.8 nm or less. In addition, the lower limit value of the height H indicating the peak value of the frequency of the height distribution curve is not particularly limited, but is preferably 6.0 nm or more, more preferably 7.0 nm or more, More preferably, it is 8.5 nm or more.

On the other hand, FIG. 6 is a height distribution curve in a region of 10 μm × 10 μm arbitrarily selected on the surface of the sliding water-repellent layer of Comparative Example 1. FIG. 2 is an AFM observation image of the sliding water-repellent layer surface of the member obtained in Comparative Example 1.
In FIG. 6, the height H indicating the frequency peak value of the height distribution curve of Comparative Example 1 is greater than the height H indicating the frequency peak value of the height distribution curves of Reference Examples 1 to 3. . This is because, in Comparative Example 1, the sea-island structure on the surface of the sliding water-repellent layer is greatly collapsed, and the altitude of the sea portion is not uniform as shown in FIG. Thus, when the sea-island structure collapses and the height H indicating the peak value of the frequency of the height distribution curve increases, the sliding water repellency is adversely affected.

In the present invention, the height distribution curve is an approximated curve obtained by linear interpolation of values in each section of the height distribution histogram. Further, the value (frequency) of each section is assigned to the peak center of each section of the histogram. For example, when a certain section of the histogram is Xnm to Ynm, the value (frequency) of the section is assigned to the position of (X + Y) / 2 nm. Moreover, it is preferable that the width of the section is sufficiently narrowed in the histogram that is the basis of the height distribution curve in order to accurately reflect the height distribution state of the sea-island structure on the sliding water-repellent layer surface. If the width of the section is 0.2 nm or less, the height distribution state can be accurately reflected. On the other hand, when the width of the section is too narrow, the influence of noise increases. For this reason, the width of the section is preferably 0.05 to 0.2 nm. For example, in Reference Examples 1 to 3 and Comparative Example 1 described later, the width of the section is 0.098 nm.
However, data with a height of 25 nm or more was excluded from the calculation as foreign matter.

It is preferable that the sliding water-repellent layer has one inflection point of the height distribution curve on the side lower than the height H indicating the peak value of the frequency of the height distribution curve.
When the sea portion is uniform and shallow like the AFM observation image of FIG. 1, the height distribution curve on the side lower than the height H indicating the frequency peak value is smooth as shown in FIGS. There is one inflection point. On the other hand, when the sea-island structure on the surface of the sliding water-repellent layer is greatly collapsed as shown in the AFM observation image of FIG. 2 and the altitude of the sea portion is not uniform, the height H indicating the peak value of the frequency is obtained as shown in FIG. The height distribution curve on the lower side is swollen and not smooth.
That is, the fact that the height distribution curve on the side lower than the height H indicating the frequency peak value has one inflection point means that the altitude of the sea portion is uniform. For this reason, the effect of this invention can be exhibited more easily by having one inflection point.
Note that since the inflection point is counted even by minute noise, it is preferable to calculate the inflection point based on data obtained by averaging the widths of a plurality of sections. For example, in Reference Examples 1 to 3 and Comparative Example 1 described later, the inflection points are calculated based on data obtained by averaging data acquired in one section 0.098 nm every five sections.

The sliding water-repellent layer has a height H indicating a peak value of the frequency of the height distribution curve on the surface of the sliding water-repellent layer, and an altitude of heights indicating a half of the peak value of the frequency of the height distribution curve. It is preferable that the height H _{1 / 2L} on the lower side satisfies the relationship of the following formula (I).
H-H _{1 / 2L} ≦ 2.5nm (I)

3 to 5 are height distribution curves in an arbitrarily selected region of 10 μm × 10 μm on the sliding water-repellent layer surface of Reference Examples 1 to 3. FIG. In FIGS. 3 to 5, the height H indicating the peak value (frequency 100) of the frequency of the height distribution curve and the height on the lower elevation side of the height indicating 1/2 (frequency 50) of the peak value. The difference from H _{1 / 2L} (H−H _{1 / 2L} ) represents the half width on the sea side in the sea-island structure on the surface of the sliding water-repellent layer.
The sliding water-repellent layer preferably has a half-width (H-H _{1 / 2L} ) on the sea side of 2.5 nm or less, more preferably 2.0 nm or less, still more preferably 1.8 nm or less, and even more preferably. Is 1.5 nm or less. The half width at half maximum (H-H _{1 / 2L} ) on the sea side is less than 2.5 nm. The sea island structure has a sea level with a certain altitude lower than 2.5 nm. It indicates that the sea portion is uniform and shallow as in the AFM observation image of FIG. Therefore, by satisfying that the half width at half maximum (HH _{1 / 2L} ) on the sea side is 2.5 nm or less, the effect of the present invention can be easily achieved. In addition, even if the lower limit value of the half width at half maximum (HH _{1 / 2L} ) on the sea side is about 0.8 nm, it can be used.

Further, the sliding water-repellent layer has a high altitude of the height H indicating the peak value (frequency 100) of the height distribution curve and the height indicating 1/2 (frequency 50) of the peak value. The height H _{1 / 2H} preferably satisfies the following formula (II) from the viewpoint of exhibiting the effects of the present invention.
H _{1 / 2H} −H ≦ 3.0 nm (II)
The above formula (II) represents the half width at half maximum on the island side in the sea-island structure on the surface of the sliding water-repellent layer. The half width at half maximum (H _{1 / 2H} -H) on the island side is preferably 3.0 nm or less, more preferably 2.5 nm or less, and still more preferably 2.0 nm or less. The half-width at half maximum (H _{1 / 2H} -H) on the island side is 3.0 nm or less. In the above-mentioned sea-island structure, there are many island portions that are higher than the sea part and have a certain altitude to 3.0 nm or less. Represents the existence. Therefore, by satisfying that the half width at half maximum (H _{1 / 2H} -H) on the island side is 3.0 nm or less, the effect of the present invention can be easily achieved. In addition, even if the lower limit of the half width on the island side (H _{1 / 2H} -H) is about 1.4 nm, it can be used.

Furthermore, the sliding water-repellent layer has an altitude of the height H indicating the peak value (frequency 100) of the height distribution curve and the height indicating 1/3 (frequency 100/3) of the peak value. From the viewpoint of exhibiting the effects of the present invention, the lower side height H _{1 / 3L} preferably satisfies the following formula (III).
H-H _{1 / 3L} ≦ 3.0 nm (III)
The above formula (III) represents the 1/3 width on the sea side in the sea-island structure on the surface of the sliding water-repellent layer. The sea-side 1/3 width (HH _{1 / 3L} ) is preferably 3.0 nm or less, more preferably 2.8 nm or less, and even more preferably 2.5 nm or less.
If the 1/3 width (H-H _{1 / 3L} ) on the sea side is 3.0 nm or less, the sea-island structure has few places lower than the sea part having the above-mentioned constant elevation, and the sea part The altitude of becomes uniform, and the effect of the present invention can be easily exhibited. In addition, even if the lower limit of the sea side 1/3 width (HH _{1 / 3L} ) is about 1.4 nm, it can be used.
On the other hand, among the height H indicating the peak value (frequency 100) of the frequency of the height distribution curve and the height indicating 1/3 (frequency 100/3) of the peak value, the height H ₁ on the higher altitude side. _/ difference between _3H (H 1 _{/ 3H} -H) represents the 1/3 width of the island side of the island structure of the sliding water-repellent layer. The 1/3 width (H _{1 / 3H} -H) on the island side is preferably 3.5 nm or less, more preferably 3.0 nm or less, and further preferably 2.5 nm or less.
If the 1/3 width (H _{1 / 3H} -H) on the island side is 3.5 nm or less, the sea-island structure has fewer protruding points than the island portion having the above-mentioned constant elevation, and the island The altitude of the part becomes uniform, and the effects of the present invention can be easily exhibited. Note that the lower limit of the 1/3 width (H _{1 / 3H} -H) on the island side can be used even if it is about 1.4 nm.

Further, the sliding water-repellent layer has a height H indicating the peak value (frequency 100) of the height distribution curve and a side having a lower altitude of the height indicating 1/10 (frequency 10) of the peak value. It is preferable from the viewpoint of exhibiting the effect of the present invention that the height H _{1 / 10L} of the above satisfies the following formula (IV).
H-H _{1 / 10L} ≦ 10.0nm (IV)
The above formula (III) represents the sea side 1/10 width in the sea-island structure on the surface of the sliding water-repellent layer. The sea-side 1/10 width (H-H _{1 / 10L} ) is preferably 10.0 nm or less, more preferably 9.0 nm or less, and still more preferably 8.5 nm or less.
If the sea side 1/10 width (H-H _{1 / 10L} ) is 10.0 nm or less, the sea part in the sea-island structure does not have an extremely large recess, and the sea part has a uniform altitude. Thus, the effects of the present invention can be easily achieved. In addition, even if the lower limit of the sea side 1/10 width (H-H _{1 / 10L} ) is about 7.0 nm, it can be used.
On the other hand, among the height H indicating the peak value (frequency 100) of the frequency of the height distribution curve and the height indicating 1/10 (frequency 10) of the peak value, the height H _{1 / 10H} on the higher altitude side. (H _{1 / 10H} -H) represents the 1/10 width on the island side in the sea-island structure on the surface of the sliding water-repellent layer. The island-side 1/10 width (H _{1 / 10H} -H) is preferably 7.5 nm or less, more preferably 6.5 nm or less, and still more preferably 5.5 nm or less.
If the 1/10 width (H _{1 / 10H} -H) on the island side is 7.5 nm or less, there is no island part that protrudes extremely in the sea-island structure, and the island part has a uniform altitude. The effect of the present invention can be easily exhibited. The lower limit of the 1/10 width (H _{1 / 10H} -H) on the island side can be used even if it is about 3.8 nm.

The sliding water-repellent layer preferably has a three-dimensional skewness SRsk on the surface satisfying the following condition (i) from the viewpoint of further exerting the effects of the present invention.
0 <SRsk (i)

The three-dimensional skewness SRsk on the surface of the sliding water-repellent layer is an index representing the symmetry of the surface-shaped curved surface with the average plane as the center, and indicates the deviation of the surface height distribution. When SRsk = 0, it indicates that the height distribution of the surface irregularities is symmetric with respect to the average line. In addition, when 0> SRsk, the height distribution is biased upward with respect to the average surface, and when 0 <SRsk, it is biased downward with respect to the average surface.
Since the surface of the sliding water-repellent layer is 0 <SRsk, it indicates that a thin protrusion (island portion) is appropriately present on the surface of the sliding water-repellent layer.
Further, the upper limit value of the three-dimensional skewness SRsk on the surface of the sliding water-repellent layer is not particularly limited, but is preferably 3 or less, more preferably 2.6 or less, and still more preferably from the viewpoint of having a moderately high protrusion. Is 2.0 or less.

In the present invention, SRsk is a three-dimensional extension of the skewness Rsk of the roughness curve of the two-dimensional roughness parameter described in JIS B0601: 1994, and the orthogonal coordinate axes X and Y axes are placed on the reference plane. When the measured surface shape curve is z = f (x, y), and the reference surface size is Lx, Ly, the following equation (a) is calculated.
Here, Sq is the root mean square deviation of the surface height distribution defined by the following formula (b).
In the present invention, the value of SRsk is calculated by measuring 20 points in the above measurement area with the measurement area in the range of Lx = 10 μm and Ly = 10 μm, and calculating the average of the measured 20 points.
It should be noted that the values of SRa and SRz described later are similarly measured by measuring 20 points in the measurement area and calculating the average.

From the viewpoint of further exerting the effect of the present invention, it is preferable that the three-dimensional arithmetic average roughness SRa of the surface of the sliding water-repellent layer satisfies the following condition (ii).
0.3 nm ≦ SRa ≦ 3.0 nm (ii)
The SRa can be used as an index of flatness, and the smaller the SRa on the sliding water-repellent layer surface, the higher the flatness.
The three-dimensional arithmetic average roughness SRa of the surface of the sliding water-repellent layer is preferably from 0.3 nm to 3.0 nm, more preferably from 0.5 nm to 2.5 nm, and more preferably from 0.6 nm to 2. It is 0 nm or less, more preferably 0.6 nm or more and 1.5 nm or less. That SRa satisfies the condition (ii) indicates that the protrusions are present in an appropriate amount in the vicinity of the sliding water-repellent layer surface, and that the non-protrusion parts have a gentle wave shape. For this reason, when SRa satisfies the condition (ii), the effect of the present invention can be more easily exhibited.

In the present invention, SRa is obtained by expanding the arithmetic average roughness Ra of the two-dimensional roughness parameter described in JIS B0601: 1994 to three dimensions, and placing the orthogonal coordinate axes X and Y axes on the reference plane, When the vertical curved surface is Z (x, y), the following formula (c) is used.
(Where A = Lx × Ly)

From the viewpoint of further exerting the effects of the present invention, it is preferable that the three-dimensional ten-point average roughness SRz of the surface of the sliding water-repellent layer satisfies the following condition (iii).
SRz ≦ 20.0 nm (iii)
Here, in the present invention, SRz is obtained by extending the ten-point average roughness Rz of the two-dimensional roughness parameter described in JIS B0601: 1994 to three dimensions.
The three-dimensional ten-point average roughness SRz of the sliding water-repellent layer surface is preferably 20.0 nm or less, more preferably 5.0 nm to 16.0 nm, and still more preferably 6.0 nm to 13.0 nm.

  In addition, it is preferable to measure a three-dimensional roughness curved surface using an interference microscope from simplicity. Examples of such an interference microscope include “New View” series manufactured by Zygo.

  The thickness of the sliding water-repellent layer is not particularly limited, but from the viewpoint of sliding water repellency and durability, the average thickness is preferably 1 to 30 nm, and more preferably 1 to 20 nm.

The sliding water-repellent layer contains a perfluoro structure and a siloxane structure. When the sliding water-repellent layer contains a perfluoro structure, the surface free energy of the sliding water-repellent layer can be reduced and frost, dew, and ice can be made difficult to adhere.
If the sliding water-repellent layer contains a perfluoro structure and a siloxane structure, the perfluoro structure and the siloxane structure are not particularly limited, but a polycondensation product of an alkoxysilane having a perfluoropolyether structure (hereinafter simply referred to as “condensation”). It is also preferable that the polymer is also referred to as “polymer”. Here, in the present invention, “having a perfluoropolyether structure” means having a group containing a perfluoropolyether bond.
When the sliding water-repellent layer contains a perfluoropolyether structure, the surface free energy of the sliding water-repellent layer can be reduced and frost, dew, and ice can hardly be attached. Further, if the structure is a polycondensation of an alkoxysilane having a perfluoropolyether structure and a compound having a functional group that reacts with the alkoxy group of the alkoxysilane having the perfluoropolyether structure, the adjacent perfluoropolyether The spacing between the structural parts is wide and sparse, and the perfluoropolyether structural parts are easy to move and have flexibility, making it more difficult to attach frost, dew, and ice, and wiping off the attached frost, dew, and ice. It can be easily done.
The polycondensation product is a polycondensation product of an alkoxysilane having a perfluoropolyether structure and a compound having a functional group that reacts with the alkoxy group of the alkoxysilane having the perfluoropolyether structure.
The compound having a functional group that reacts with the alkoxy group can be used without particular limitation as long as it has a functional group that reacts with the alkoxy group. For example, an alkoxy group, a carboxyl group, a hydroxyl group, an amino group, Examples thereof include compounds having a sulfonic acid group and the like. Of these, alkoxysilane is preferable, and tetraalkoxysilane is particularly preferable from the viewpoints of reactivity and improved sliding water repellency.
Hereinafter, tetraalkoxysilane will be exemplified and described as a compound having a functional group that reacts with an alkoxy group.

The polycondensation product of an alkoxysilane having a perfluoropolyether structure is preferably a polycondensation product of an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane from the viewpoint of improving sliding water repellency.
When the polycondensation product has a structure in which an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane are polycondensated, the distance between adjacent perfluoropolyether structure parts becomes wide and sparse, and the perfluoropolyether It is considered that the structure part is easy to move and has flexibility, so that sliding property is improved, frost, dew and ice are hardly attached, and frost, dew and ice can be easily wiped off. . In addition, the above-described sea-island structure can be easily formed.
In addition, it is preferable that the ratio of the said condensation polymer which occupies the said sliding water-repellent layer is 60-100 mass%, It is more preferable that it is 70-100 mass%, It is further that it is 80-100 mass%. preferable.

(Alkoxysilane having perfluoropolyether structure)
The alkoxysilane having a perfluoropolyether structure used as a raw material for the polycondensation product has a perfluoropolyether structure, thereby lowering the surface free energy of the sliding water-repellent layer and being hardly attached with frost, dew, or ice. To do. Furthermore, the interval between adjacent perfluoropolyether structure parts is wide and sparse, and the perfluoropolyether structure parts are easy to move and have flexibility, so that frost, dew, and ice are more difficult to attach and attached. It is thought to facilitate wiping of frost, dew, and ice.
Examples of the alkoxysilane having the perfluoropolyether structure include compounds represented by the following general formulas (1) to (4), and are represented by the following general formula (1) from the viewpoint of sliding water repellency. Are preferred.

(In the formula, R ² is an alkyl group having 1 to 6 carbon atoms. However, a plurality of R ² may be the same or different. R ^{3 to} R ¹⁰ are each independently 1 to 12 carbon atoms. Z ¹ is a 1 to 10 valent organopolysiloxane group having a siloxane bond, Z ² is a 2 to 10 valent organopolysiloxane group having a siloxane bond, Q is (Rf is a linear or branched perfluoroalkyl group, n is an integer of 1 to 200, and m is an integer of 1 to 10.)

Examples of the alkyl group having 1 to 6 carbon atoms of R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and an isopentyl group. Group, neopentyl group, n-hexyl group, isohexyl group and the like. From the viewpoint of sliding water repellency and reactivity, a methyl group and an ethyl group are preferable, and a methyl group is more preferable.
R ^{3 to} R ¹⁰ are each independently a divalent organic group having 1 to 12 carbon atoms, preferably 3 to 8 carbon atoms. Specifically, methylene group, ethylene group, propylene group (trimethylene group) , Methylethylene group), butylene group (tetramethylene group, methylpropylene group), alkylene group such as hexamethylene group and octamethylene group, arylene group such as phenylene group, or a combination of two or more of these groups. It is done. In addition, these groups may contain an ether bond, an amide bond, an ester bond, and a vinyl bond, and may further contain an oxygen atom, a nitrogen atom, and a fluorine atom.

The 2-10 divalent organopolysiloxane group having a siloxane bond in the Z ^2, for example, groups represented by the following general formula (5-1) to (5-12).

  Among the groups represented by the general formulas (5-1) to (5-12), from the viewpoint of obtaining sliding water repellency which is an effect of the present invention, the general formulas (5-1), (5-2), Groups represented by (5-3), (5-4) and (5-7) are preferred.

The group containing a perfluoropolyether bond of the Q, for _{example, -CF 2 O -, - CF} 2 CF 2 O -, - CF 2 CF 2 CF 2 O -, - CF (CF 3) CF 2 O- , -OCF ₂ OCF ₂ CF _2- , -CF ₂ CF ₂ CF ₂ CF ₂ O-, -CF ₂ CF (CF ₃ ) CF ₂ O-, -CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ O- , —C (CF ₃ ) ₂ O— and the like.
Among them, from the viewpoint of sliding _{repellent, -CF 2 CF 2 O -,} - CF 2 CF 2 CF 2 O -, - CF (CF 3) CF 2 O -, - OCF 2 OCF 2 CF 2 -, - CF 2 CF (CF ₃ ) CF ₂ O— is preferred. These may include only one type or two or more types.

Rf is a perfluoroalkyl group having a linear or branched structure, and a linear perfluoroalkyl group is preferable from the viewpoint of obtaining the effects of the present invention.
Examples of the linear perfluoroalkyl group include a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group, an undecafluoropentyl group, a tridecafluorohexyl group, and the like. Perfluoroalkyl groups having a structure include 1- (trifluoromethyl) -1,2,2,2-tetrafluoroethyl group, 1,1-di (trifluoromethyl) -2,2,2-trifluoroethyl group Group, 2- (trifluoromethyl) -1,1,3,3,3-pentafluoropropyl group and the like.

The n is an integer of 1 to 200, and preferably 2 to 100, more preferably 3 to 60, from the viewpoint of sliding water repellency. By setting n to 1 or more, the substrate surface can be sufficiently covered, the surface free energy of the sliding water-repellent layer surface is reduced, and sliding water repellency can be improved. By setting n to 200 or less, the reactivity of the alkoxysilyl group (—Si (OR ² ) ₃ ) can be increased.

  M is an integer of 1 to 10, and preferably 1 to 7, more preferably 1 to 5, from the viewpoint of sliding water repellency. When m is 1 or more, slipperiness is improved, and higher sliding water repellency is obtained. By setting m to 10 or less, an increase in surface free energy can be suppressed, and a decrease in sliding water repellency can be suppressed.

The alkoxysilane having a perfluoropolyether structure is preferably trimethoxysilane having a perfluoropolyether structure from the viewpoint of sliding water repellency and reactivity.
In addition, as the alkoxysilane having the perfluoropolyether structure, “X-71-195”, “KY-178”, “KY-164”, “KY-108”, “KP” manufactured by Shin-Etsu Chemical Co., Ltd. -911 "," Optool DSX "," Optool DSX-E "manufactured by Daikin Industries, Ltd. are commercially available, and" X-71-195 "is preferable from the viewpoint of productivity and sliding water repellency. .

(Tetraalkoxysilane)
Since tetraalkoxysilane has four alkoxy groups, the reactivity with the alkoxysilane having the perfluoropolyether structure is high. As the tetraalkoxysilane, for example, a compound represented by the following general formula (6) is preferably used.

(In the formula, R ¹ is an alkyl group having 1 to 6 carbon atoms, provided that a plurality of R ¹ may be the same or different.)

Examples of the alkyl group having 1 to 6 carbon atoms of R ¹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and an isopentyl group. Group, neopentyl group, n-hexyl group, isohexyl group and the like. Of these, a methyl group and an ethyl group are preferable from the viewpoint of sliding water repellency and reactivity, and specifically, at least one selected from tetramethoxysilane and tetraethoxysilane is preferable.

[Base material]
As a base material used for the member for low temperature environments of this invention, the material which processed the surface with various inorganic materials, such as a glass plate, a glass film, a glass sheet, an aluminum oxide plate, and a spin-on-glass (SOG) material, for example. And various organic resin materials such as thermoplastic resins, thermosetting resins, ionizing radiation curable resins, organic-inorganic composite materials, metal materials, and the like. Among these, from the viewpoint of reactivity with silane, those having a hydroxyl group on the surface are preferable, and from the viewpoints of workability of the material, mechanical strength of the resulting member, and ease of formation of the sliding water-repellent layer. A glass plate, a glass film, a glass sheet, a material whose surface is processed with a spin-on-glass (SOG) material, or an organic-inorganic composite material is preferable, and a glass plate, a glass film, or a glass sheet is more preferable. The glass plate, glass film, glass sheet, and resin substrate may be chemically strengthened for the purpose of improving strength. Examples of SOG materials include alkylsiloxane materials such as methylsiloxane, hydroxysilsesquioxane materials, silazane materials, silsesquioxane materials, and silsesquioxane materials in terms of durability. Is preferred.
Examples of commercially available SOG materials include an interlayer insulating film coating material “HSG” (trade name, manufactured by Hitachi Chemical Co., Ltd.) and an OCN series manufactured by Tokyo Ohka Kogyo Co., Ltd. Commercially available organic-inorganic composite materials include organic-inorganic composite materials (trade name “NH-1000G”, manufactured by Nippon Soda Co., Ltd.), Arakawa Chemical Industries, Ltd. Composeran SQ series manufactured by Co., Ltd.
In addition, the shape of the base material may be a planar structure or a three-dimensional structure.

The thickness of the glass plate, glass film, glass sheet, and resin base material used as the base material when transparency is required is not particularly limited, but is preferably 0.01 from the viewpoint of optical properties and durability. -100 mm, more preferably 0.02-10 mm. The thickness of the resin film used as the substrate is preferably 1 to 500 μm, more preferably 3 to 300 μm, from the viewpoint of strength and optical properties.
A low reflection layer may be formed on the surface of the substrate in order to improve optical characteristics. The low reflection layer can be formed by laminating a plurality of inorganic compounds by sputtering or the like. In addition, on the surface of the base material and the low reflection layer, in order to improve adhesion and improve long-term reliability in the use environment, application of a coating called an anchor agent or primer, or as an adhesive layer The inorganic layer may be formed in advance. As the inorganic layer, a silicon-based compound is preferable, and SiO ₂ and SiOx are more preferable from the viewpoints of adhesiveness and durability. The adhesive layer can be formed using a method such as a vapor deposition method, a sputtering method, an ion plating method, or a chemical vapor deposition method. Moreover, in order to improve adhesiveness irrespective of the presence or absence of formation of these layers, you may perform physical processes, such as a corona discharge process, an oxidation process, and a plasma process.
Further, from the viewpoint of use as a traffic light surface, an automobile window, a window glass, etc., the total light transmittance of the substrate is preferably 85% or more, and more preferably 90% or more. The transmittance | permeability of a base material can be measured by the method based on JISK7361-1 (the test method of the total light transmittance of a plastic-transparent material).

[Method of manufacturing low temperature environment member]
Next, the manufacturing method of the member for low-temperature environments mentioned above is demonstrated.
The method for producing a low-temperature environment member of the present invention was obtained by hydrolyzing and polycondensing an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane in a mixed solvent of an organic solvent, water and an acid. It has the process (1) which prepares the composition containing a condensation polymerization material, and the process (2) which apply | coats this composition to this base material, and forms a sliding water-repellent layer.

(Process (1))
In this step, for example, water and an acid are mixed and stirred in a mixed solvent containing an organic solvent, an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane, and the alkoxysilane having the perfluoropolyether structure is stirred. And the tetraalkoxysilane is hydrolyzed and then subjected to condensation polymerization to obtain a condensation polymer.
Specifically, the polycondensation product is obtained by hydrolyzing the alkoxy group of the alkoxysilane having the perfluoropolyether structure and the alkoxy group of the tetraalkoxysilane to form silanol groups, respectively, It is obtained by polycondensing a silanol group possessed by an alkoxysilane having an ether structure and a silanol group possessed by the tetraalkoxysilane.

  The hydrolysis and polycondensation reactions are preferably performed under a certain atmosphere in which these reactions occur appropriately. Specifically, it is preferably performed for about 0.1 to 200 hours in the range of −25 to 120 ° C., more preferably for about 0.5 to 150 hours at −10 to 100 ° C., and 0 to 70 ° C. It is more preferable to carry out for about 1 to 100 hours. For example, it is about 1 to 50 hours at 10 to 60 ° C. and about 2 to 12 hours at 20 to 50 ° C. By carrying out the reaction temperature and reaction time within the above ranges, the above-mentioned sea-island structure can be easily formed, and the above-mentioned conditions (i) to (iii) can be easily satisfied.

As the alkoxysilane and tetraalkoxysilane having the perfluoropolyether structure, those described above can be used.
The weight average molecular weight of the alkoxysilane having the perfluoropolyether structure can be determined by GPC measurement.
The weight ratio of the alkoxysilane having the perfluoropolyether structure and the tetraalkoxysilane is preferably 1: 0.1 to 10.0, more preferably 1: 0.15 to 8.0, and still more preferably. 1: 0.2-6.0. By setting it within the above range, sliding water repellency can be improved. In addition, the above-described sea-island structure is easily formed, and the above-described conditions (i) to (iii) are easily satisfied.

As the organic solvent, a fluorine-based solvent is preferably used from the viewpoint of dissolving the alkoxysilane having the perfluoropolyether structure. Further, from the viewpoint of solubility in water, a mixed organic solvent of a fluorinated solvent and an amphiphilic solvent is preferable.
As the amphiphilic solvent, for example, water-soluble organic solvents such as alcohols and ketones are preferably used. Examples of the alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, and tertiary butyl alcohol. Examples of the ketones include acetone, methyl ethyl ketone, and methyl isobutyl ketone. As other water-soluble organic solvents, tetrahydrofuran, dioxane, acetonitrile, ethyl acetate and the like are used. These can be used alone or in admixture of two or more.

  The compounding amount of the organic solvent in the composition is preferably 90.000 to 99.999% by mass, more preferably 92.00 to 99.99% by mass, and further preferably 95.0 to 99.9% by mass. . By setting it to 90.000% by mass or more, the reaction in the mixed solvent can be promoted uniformly, and the sliding water-repellent layer formed from the composition can be made uniform and transparent, 99.999% by mass By setting it as below, a sufficient sliding water-repellent layer can be formed on the substrate surface.

  Examples of water include ion exchange water and distilled water. The amount of water contained in the mixed solvent is not particularly limited as long as it is 0.001% by mass or more, but is preferably 0.001-1.000% by mass, more preferably 0.005- It mix | blends in the ratio of 0.500 mass%. By setting it as 0.001 mass% or more, the said hydrolysis is accelerated | stimulated, and precipitation of the alkoxysilane which has a perfluoro polyether structure can be suppressed by setting it as 1.000 mass% or less.

  The acid is not particularly limited as long as it has an action of promoting the hydrolysis, and includes hydrochloric acid, sulfuric acid, nitric acid, boric acid, phosphoric acid, succinic acid, acetic acid, formic acid, oxalic acid, citric acid, benzoic acid, etc. From the viewpoint of reactivity and removal from the sliding water-repellent layer during drying, hydrochloric acid is preferred. Moreover, the compounding quantity of the acid contained in the mixed solvent is preferably 0.000001 to 10.000000 mass%, more preferably 0.00001 to 5.00000 mass%, from the viewpoint of promoting the hydrolysis. More preferably, it is 0.0001-1.0000 mass%.

In addition to the above components, the above composition contains a photoacid generator, a photobase generator, and the like that are generally blended in this type of composition, as long as the effects of the present invention are not impaired. can do. By blending the photoacid generator or photobase generator, a stronger sliding water-repellent layer can be formed.
Moreover, the solid content concentration of the composition is preferably 0.01 to 15.00% by mass, more preferably 0.05 to 10.00% by mass, and still more preferably 0.1 to 5.0% by mass. . By setting the content to 0.01% by mass or more, curing of the sliding water-repellent layer can be promoted, and by setting the content to 15.00% by mass or less, coloring of the sliding water-repellent layer and a decrease in sliding water-repellent layer are suppressed. be able to.

(Process (2))
A sliding water-repellent layer is formed by applying the composition prepared in the above step (1) onto a substrate, drying and curing.
The method for applying the composition may be any method that can be applied uniformly to a desired thickness, and may be appropriately selected from conventionally known methods. For example, gravure coating method, knife coating method, dip coating method, spray coating method, air knife coating method, spin coating method, roll coating method, curtain coating method, die coating method, casting method, bar coating method, extrusion coating method, etc. Is mentioned.

  The setting conditions for the drying treatment of the film formed by applying the above composition vary depending on the raw material, the solvent, the temperature and humidity of the atmosphere, but are controlled in a certain atmosphere suitable for obtaining the effects of the present invention. It is preferable to do in the situation. For example, it is usually performed at room temperature (25 ° C.) to 300 ° C. for about 0.1 to 48 hours, more preferably at 25 to 250 ° C. for about 0.2 to 24 hours. These treatments may be completed under one kind of atmosphere, or may be carried out stepwise under two or more kinds of atmospheres.

[Evaluation of materials for low temperature environment]
Conventionally, the sliding water-repellent layer has been studied to increase the contact angle between water and fats and oils in order to prevent frost, dew, and ice from sticking. On the other hand, in the present invention, by increasing the contact angle between water and oil and fat, and by reducing the sliding angle of both, high sliding property is obtained, so that frost, dew, and ice are hardly attached, and It makes it easy to wipe off frost, dew and ice.
The sliding property can be evaluated by measuring the sliding angle of pure water and n-hexadecane. The smaller the sliding angle, the better the sliding property. The sliding angle is a slope in which 10 μL of pure water and 3 μL of n-hexadecane are dropped in a horizontal state on the surface of the sliding water-repellent layer of the member to be measured, the member is gradually tilted, and the droplet starts to slide. It is obtained by measuring the angle (sliding angle). As the measuring device, for example, a contact angle meter “DM 500” manufactured by Kyowa Interface Science Co., Ltd. can be used. Specifically, the sliding angle can be measured by the method described in Examples.

In the low-temperature environment member of the present invention, the contact angle of pure water on the surface of the sliding water-repellent layer is preferably 95 ° or more and 120 ° or less, more preferably 112 ° or more and 120 ° or less, and further preferably 114 ° or more. 120 ° or less. Further, the sliding angle of pure water on the surface of the sliding water-repellent layer is preferably 30 ° or less, more preferably 15 ° or less, and further preferably less than 8 °.
When the contact angle is 95 ° or more, it indicates that the sliding water-repellent layer has low surface free energy, and frost, dew, and ice can be hardly attached. Further, the member of the present invention does not have a so-called super water-repellent surface having a pure water contact angle of 120 ° or less and a pure water contact angle of 150 ° or more.
When the sliding angle is 30 ° or less, the sliding property of the sliding water-repellent layer surface is improved, frost, dew and ice are hardly attached, and attached frost, dew and ice can be easily wiped off. .
In the present invention, the reason why the contact angle can be 95 ° or more is considered to be that the condensation polymer has a perfluoropolyether structure site. The sliding angle can be set to 30 ° or less because the polycondensate is a polycondensation of an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane. It is considered that the intervals between the polyether structure sites are wide and sparse, and the perfluoropolyether structure sites are easy to move and have flexibility.
The contact angle is measured by the θ / 2 method with respect to pure water and n-hexadecane using a contact angle measuring device (for example, a contact angle meter “DM 500” manufactured by Kyowa Interface Science Co., Ltd.). Is required. Specifically, the contact angle can be measured by the method described in Examples.

  In the member for low temperature environment of the present invention, the contact angle of n-hexadecane on the surface of the sliding water-repellent layer is preferably 50 ° or more, more preferably 55 ° or more, and further preferably 60 ° or more. Further, the sliding angle of n-hexadecane on the sliding water-repellent layer surface is preferably 15 ° or less, more preferably 10 ° or less, and further preferably 6 ° or less.

The inventors of the present invention have a sliding water-repellent layer containing a polycondensation product of an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane so that the surface of the sliding water-repellent layer and a cloth or the like used for wiping fingers or the like can be obtained. It has been found that the coefficient of friction is reduced to improve the slipperiness. The member of the present invention reduces the surface free energy of the sliding water-repellent layer by increasing the contact angle between water and oil and fat, and high sliding properties can be obtained by reducing the sliding angle between water and oil and fat. In addition, since high slipperiness is obtained, frost, dew and ice can be further prevented from sticking to the surface of the sliding water-repellent layer, and the attached frost, dew and ice can be easily wiped off.
As described above, the low-temperature environment member of the present invention has extremely excellent sliding water repellency that cannot be obtained by the conventional sliding water-repellent member. It is considered that the interval is wide and sparse, and the perfluoropolyether structure part is easy to move and has flexibility.
In the present invention, “slidability” is an index representing the smoothness of the surface of the sliding water-repellent layer of the member. Specifically, the slip property can be evaluated by the method described in Examples.

  Furthermore, the low temperature environment member of the present invention has also been found to have durability that can withstand practical use. In the low temperature environment member of the present invention, as shown in FIG. 11, the sliding water-repellent layer and the substrate are immobilized via a covalent bond between the hydroxyl group which is an oxygen-containing polar group on the substrate surface. Therefore, durability that can withstand practical use can be exhibited.

  The member for low-temperature environment of the present invention has excellent sliding water repellency, and therefore has excellent frost resistance, non-condensation property, and non-icing property. Therefore, traffic lights, automobile windows, window glass, aircraft surface materials, and outdoor parts of air conditioners. It can be suitably used for a heat exchanger of a heat pump unit or the like. In addition, it has excellent antifouling properties, so that it can easily get fingerprints, sebum, sweat, etc. on its surface when touched by hand, such as liquid crystal display, plasma display, organic / inorganic EL display, electronic paper, VFD, EPD Image display devices such as touch panels, mobile phones, music players, and other portable electronic devices, optical recording media such as CDs, DVDs, and Blu-ray discs, window glass for automobiles, trains, aircraft, etc., inner walls for exterior walls, wallpaper, etc. It is suitably used as a surface material for home appliances, in-vehicle panels and the like.

Hereinafter, the present invention will be specifically described with reference to reference examples, comparative examples, and examples. In addition, this invention is not limited to the form as described in an Example.
Evaluation of the members of the reference example, the comparative example, and the example was performed as follows.

(1) Shape of surface of sliding-down water repellent layer <height showing peak value, half width at half maximum, 1/3 width, 1/10 width>
Using an Atomic Force Microscope (AFM) SPM-9600 manufactured by Shimadzu Corporation, each member obtained in Reference Example, Comparative Example, and Example in the On-Line (Measurement) mode in the software: SPM Manager The shape of the surface of the sliding water-repellent layer was measured, and histogram data of height distribution was obtained. Thereafter, an inclination correction process was performed using an Off-Line (analysis) mode to obtain a gradation image when the height: 0 nm was black and the height: 25 nm or more was white (vertical: 512 × horizontal). : 512 = 262144 pixels). The image was analyzed using Photoshop (registered trademark). Histogram data of height distribution when each pixel has a gradation of 256 gradations (black: 0, white: 255) is obtained (1 interval 0.098 nm), and a height H indicating a peak value of frequency, Half width at sea side (H-H _{1 / 2L} ), Half width at island side (H _{1 / 2H} -H), 1/3 width at sea side (H-H _{1 / 3L} ), 1/10 at sea side The width (H−H 1/10 _L ), the 1/3 width on the island side (H _{1 / 3H} −H), and the 1/10 width on the island side (H _{1 / 10H} −H) were calculated. The results are shown in Table 1. 3 to 6 are histogram data of height distributions of Reference Examples 1 to 3 and Comparative Example 1.
(AFM measurement conditions)
Measurement mode: Phase scanning range: 10 μm × 10 μm,
Scanning speed: 0.8-1Hz
Number of pixels: 512 × 512
Cantilever used: NCHR manufactured by Nanoworld (resonance frequency: 320 kHz, spring constant 42 N / m)
(AFM analysis conditions)
Tilt correction: Line fit <Ratio of island part in sea-island structure>
The ratio of the island part of the sea-island structure is calculated by measuring the shape of the sliding water-repellent layer surface with AFM and calculating the average value of the height data of the sliding water-repellent layer surface. Number × 100 / number of all measurements], 20 points were measured, and the average of the measured 20 points was calculated. However, data with a height of 25 nm or more was excluded from the calculation as foreign matter. The results are shown in Table 1.
<Number of inflection points>
Using the histogram data of the height distribution used when calculating the height H indicating the frequency peak value, the inflection point of the height distribution curve on the side lower than the height H indicating the frequency peak value is used. Numbers were calculated. Specifically, the histogram data of the height distribution is re-acquired based on the data obtained by averaging the data acquired in 1 interval 0.098 nm every 5 intervals, and the peak value of the frequency is indicated by the re-acquired histogram data. The number of inflection points in the height distribution curve on the side lower than the height H was calculated.

<SRa, SRsk, SRz>
Using a white interference microscope (New View 7300, manufactured by Zygo), measurement and analysis of the shape of the sliding water-repellent layer surface of each member obtained in Reference Examples, Comparative Examples, and Examples were performed. The results are shown in Table 1.
The measurement / analysis software used was Micro Pro Version 9.0.10 64-bit Microscope Application.
(Measurement condition)
Objective lens: 100 times Zoom: 2 times Measurement area: 50 μm × 50 μm
Resolution (interval per point): 0.57 μm
(Analysis conditions)
Removed: Plane
Filter: OFF
FilterType: OFF
Low wavelength: OFF
High wave length: OFF
Remove spikes: OFF
Spike Height (xRMS): OFF
(2) Measurement of contact angle The contact angle of pure water and n-hexadecane was measured using a contact angle meter “DM 500” manufactured by Kyowa Interface Science Co., Ltd. 1.5 μL of pure water is dropped on the surface of the sliding water-repellent layer of the member, and contacted from the angle of the straight line connecting the left and right end points and the apex of the dropped droplet to the solid surface according to the θ / 2 method 1 second after landing. The corner was calculated. The average value measured five times was taken as the value of the contact angle. The results are shown in Table 2.
(3) Surface free energy From the measurement result of the contact angle, the surface free energy was evaluated according to the following criteria. The larger the contact angle, the lower the surface free energy and the better. The results are shown in Table 2.
◎: Pure water 110 ° or more and n-hexadecane 60 ° or more ○: Pure water less than 110 ° 95 ° or more and n-hexadecane less than 60 ° 50 ° or more ×: Pure water less than 95 ° or n-hexadecane less than 50 ° (4) Measurement of sliding angle The sliding angle of pure water and n-hexadecane was measured using a contact angle meter “DM 500” manufactured by Kyowa Interface Science Co., Ltd. The member is placed horizontally, 10 μL of pure water and 3 μL of n-hexadecane are dropped on the surface of the sliding water-repellent layer of the member, the member is gradually tilted, and the tilt angle at which the droplet starts to slide (sliding angle) ) Was measured. The average value measured five times was taken as the sliding angle value. The results are shown in Table 2.
(5) Sliding property The sliding property was evaluated according to the following criteria from the measurement result of the sliding angle. The smaller the sliding angle, the better the sliding property. The results are shown in Table 2.
◎: Pure water less than 15 ° and n-hexadecane less than 10 ° ○: Pure water 15 ° or more and 30 ° or less, or n-hexadecane 10 ° or more and 15 ° or less ×: Pure water more than 30 ° or n-hexadecane more than 15 ° (6) Evaluation of slipperiness Ten test subjects brought their fingers into contact with the sliding water-repellent layer surface of each member prepared in Reference Examples 1 to 3 and Comparative Example 1, and the fingers were parallel to the sliding water-repellent layer surface. Moved back and forth in the horizontal direction (slide operation with a smartphone). Tactile sensation due to friction between the finger and the sliding water-repellent layer surface at that time was determined according to the following evaluation criteria, and an average value of 10 subjects was obtained. This average value was determined according to the following criteria. The results are shown in Table 2.
<Evaluation criteria>
5 points: always smooth 3 points: smooth 0 point: bad <Criteria>
○: 4.4 points or more Δ: 2.1 points or more and less than 4.4 points ×: less than 2.1 points (7) Fingerprint adhesion Artificial fingerprint solution (Isehisa Co., Ltd.) on a silicone resin plate (10 mmφ × 30 mm cylindrical shape) ), Manufactured according to JIS C 9606 appendix 4), was pressed against the sliding water-repellent layer surface of the member to attach a fingerprint. The state of fingerprint attachment was visually observed and evaluated according to the following criteria. The results are shown in Table 2.
◎: The fingerprint is strongly played and the amount of adhesion is very small. ○: The fingerprint is played and the amount of adhesion is small. Δ: The fingerprint is flipped but adheres. ×: The fingerprint adheres widely (8) Fingerprint wiping property A silicone resin plate (10mmφ × 30mm cylindrical shape) with an artificial fingerprint liquid (Isehisa Co., Ltd., compliant with JIS C9606 appendix 4) attached to the sliding water-repellent layer surface of the member is attached to the fingerprint. I let you. The attached fingerprint was wiped with Ben Cotton manufactured by Asahi Kasei Co., Ltd., and the remaining fingerprint was visually observed and evaluated according to the following criteria. The results are shown in Table 2.
◎: The fingerprint trace is completely invisible after wiping up to 3 times. ○: The fingerprint trace is completely invisible after wiping 4-7 times. △: With 8 to 10 wipes. ： Fingerprint adhesion traces are not completely visible ×: Fingerprint wipe traces are clearly visible after 10 wipes

Reference example 1
(Preparation of composition)
Fluorine-based organic solvent (product name: Novec 7300, 20.2 g), amphiphilic solvent (product name: 2-propanol, 3.5 g), and a perfluoropolyether structure 0.75 g of alkoxysilane solution (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “X-71-195”, solid content 20%) and tetraalkoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd., trade name: orthosilicic acid) Tetramethyl) In a mixed solution in which 0.051 g is mixed, 3.8 mg of water and 22.4 mg of 1M hydrochloric acid are added, and the mixture is stirred at 25 ° C. for 3 hours. The alkoxysilane having a perfluoropolyether structure and tetra Composition 1 containing a polycondensation product with alkoxysilane was obtained.
(Manufacture of parts)
The composition 1 was applied on a glass substrate (manufactured by Nippon Electric Glass Co., Ltd., trade name: OA-10G, thickness 700 μm) using a spin coater at a rotational speed of 3000 rpm, and the coating film was applied. Formed. The coating film was dried at room temperature (25 ° C.) for 12 hours, and the solvent was removed and cured to obtain a member having an average film thickness of 10 nm (estimated value).

Reference example 2
28.1 g of fluorine-based organic solvent (trade name: Novec 7300, manufactured by 3M), 4.8 g of amphiphilic solvent (trade name: 2-propanol, manufactured by Kanto Chemical Co., Inc.), having a perfluoropolyether structure 0.15 g of alkoxysilane solution (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “X-71-195”, solid content 20%), tetraalkoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd., trade name: orthosilicic acid) A member was obtained in the same manner as in Reference Example 1 except that 0.076 g of tetramethyl), 5.9 mg of water, and 31.1 mg of 1M hydrochloric acid were used.
An AFM observation image of the surface of the sliding water-repellent layer of the obtained member is shown in FIG. When the AFM observation image was analyzed, the shape of the sliding water-repellent layer surface was a sea-island structure in which a discontinuous protruding structure having a diameter of about 250 to 500 nm and a height of about 10 to 20 nm was observed.

Reference example 3
A member was obtained in the same manner as in Reference Example 2 except that the stirring time of the mixed solution was changed to 24 hours.

Comparative Example 1
A member was obtained in the same manner as in Reference Example 2 except that the stirring time of the mixed solution was changed to 168 hours.

Example The following samples were used to evaluate frost formation, condensation, icing, and durability.
Sample 1: Member prepared in Reference Example 2 (transparent substrate)
Sample 2: An organic-inorganic composite material (manufactured by Nippon Soda Co., Ltd., trade name “NH-1000G” on a polyester film (manufactured by Toyobo Co., Ltd., trade name: Cosmo Shine A4100, thickness 100 μm) using a bar coater. ]) 53 mass% methyl isobutyl ketone (MIBK) solution was applied to form a coating film. The coating film was dried at 70 ° C. for 60 seconds to remove the solvent.
Next, the coating film was irradiated with a high-pressure mercury lamp at an irradiation amount of 100 mJ / cm ² to cure the coating film, thereby obtaining a base material with a surface having a thickness of 10 μm after curing.
A sliding water-repellent layer was formed on the substrate in the same manner as in Reference Example 2. (Resin base material)
Sample 3: Untreated Corning gorilla glass (Gorilla 3, thickness 0.7 mmt)

Example 1
(Frosting)
Samples 1, 2, and 3 were affixed to the windshield of an automobile in the winter (the lowest temperature at night was -2.7 ° C.) and left overnight, and the appearance of each surface was observed early in the morning. The temperature during observation was 1 ° C.
(result)
As a result of comparing Samples 1, 2, and 3, Samples 1 and 2 were thinner than Sample 3 in the thickness of the frost, and the defrosting speed was faster.

Example 2
(Condensation)
Samples 1, 2, and 3 were used as window materials for the heat insulation box, and Samples 1, 2, and 3 were installed so that their processing surfaces were the inner surfaces of the heat insulation box. In a state where hot water was put in a container in the heat insulation box, the heat insulation box was stored in an environment at a room temperature of −7 ° C. for 2 hours, and the state of frost adhering to the inner side surfaces of the samples 1 and 2 was observed.
(result)
Samples 1 and 2 had powdery frost attached. This frost could be easily wiped off with a force that was stroking with a brush or gloves.
Sample 3 had water droplets of ice attached to it. This ice was firmly attached to the extent that it could hardly be cut with a knife.

Example 3
(Icing property 1) Snow accumulation evaluation of powder snow Samples 1, 2, and 3 were installed at angles of 45 degrees and 60 degrees from the horizontal, and artificial snow was snowed from above in an environment of -7 ° C. .
(result)
In Samples 1 and 2, snow fell and snow did not accumulate.
Sample 3 was snow-covered, and the sample installed at 45 degrees from the horizontal fell by 20 mm, and the sample installed at 60 degrees from the horizontal fell by 10 mm of snow.

Example 4
(Icing property 2) Evaluation of snow accumulation of wet snow Snow falling at 0 ° C. or higher contains a lot of water in the water state, not in the ice state, and is called wet snow. In this example, a snowfall experiment was performed in an environment of + 2 ° C.
Samples 1, 2, and 3 were placed at an angle of 45 degrees and 60 degrees from the horizontal and horizontal, and artificial snow was snowed from above in an environment of + 2 ° C.
(result)
Samples 1 and 2 installed at 60 degrees from the horizontal surface slipped before the snow fell on one side, and the snow fell off.
Samples 1 and 2 installed at 45 degrees from the horizontal level had a snow cover of about 10 mm, and then slipped and snow fell.
The samples of Samples 1 and 2 installed horizontally had snow accumulated, but after snowing 60 mm, when they were tilted 30 degrees from the horizontal, surface slip occurred and the snow fell.
The sample 3 sample installed at 60 degrees from the horizontal snow cover 13 mm, the sample 3 sample installed 45 degrees from the horizontal snow cover 20 mm, and the horizontal sample 3 sample 60 snow cover. In these samples, even if the inclination angle was increased to 90 degrees after snow accumulation, no slipping occurred and no snow fell.

Example 5
(Icing property 3) Evaluation of ice accretion of wet snow Samples 1, 2, and 3 were installed horizontally, artificial snow (+ 2 ° C) was deposited from the top by about 20 mm, and then stored in an environment of -5 ° C for 1 hour. did. The snow on each sample was cut with a knife and compared for ease of peeling.
(result)
In samples 1 and 2, the snow cover was cleanly peeled off from the cut and the glass surface was exposed.
In Sample 3, frozen snow and ice remained on the glass surface, and the glass surface could not be easily exposed even when shaved with a knife.

Example 6
(Icing properties 4)
A jig 10 having a handle shown in FIG. 7 was prepared. The jig 10 is made of SUS and is a cylinder having an inner diameter of 44 mm and a height of 30 mm, and a handle having a diameter of 10 mm is welded to the side surface thereof.
As shown in FIG. 8, the icing property was evaluated by attaching the sample 20 to the iron plate 30 and placing the jig 10 on the surface of the sample 10, and then filling the cylinder of the jig 10 with water at −7 ° C. The sample was stored in the environment all day and night, and a state where ice was icing on the surface of the sample 10 was artificially formed.
As shown in FIG. 9, the load measuring device 40 is attached to the handle portion of the jig 10 and pulled up vertically to measure the load when the specimen surface and the ice peel off. The icing property was evaluated.
(result)
Sample 1 was peeled off at 56.6N, and sample 3 was peeled off at 95.3N.

Example 7
(durability)
Sample 1 was subjected to a scratch test using steel wool to evaluate the contact angle of pure water. In the test, Bonster Steel Wool # 0000 was used, and the steel wool was applied to the surface of the sample with a load of 1 kg / cm ² and pressed. Stroke one way 70 mm, reciprocation 140 mm, scratching speed 140 mm / s, 0 to 10,000 scratches The contact angle of pure water was evaluated.
(result)
The evaluation results are shown in FIG.
As shown in FIG. 10, the pure water contact angle was maintained at 100 ° even after 10,000 abrasion tests.

(Summary of results)
As shown in Table 2, the sliding water-repellent layer has a sea-island structure containing a perfluoro structure and a siloxane structure, and the height H indicating the peak value of the height distribution curve of the sliding water-repellent layer surface is 11.8 nm or less. In Reference Examples 1 to 3, the contact angle of pure water was 112 to 116 °, and the contact angle of n-hexadecane was 66 to 67 °, both of which were excellent in low surface free energy. Moreover, the sliding angle of pure water was 3 to 20 °, and the sliding angle of n-hexadecane was 2 to 4 °. Both sliding properties were good and the evaluation of sliding property was also high.
On the other hand, in Comparative Example 1 where the height H indicating the peak value of the height distribution curve on the surface of the sliding water-repellent layer was 13.5 nm, the surface free energy was higher than that of the reference example, and the evaluation of sliding property was poor. .
In addition, it can be seen from the results of Examples 3 to 5 that it is difficult for snow accumulation on the sliding water-repellent layer of the present invention.
Thus, from the evaluation results of frost formation, condensation, icing, and durability of Examples 1 to 7, the low temperature environment member of the present invention is hardly frosted, difficult to condense, and difficult to freeze. It was confirmed that it had durability. In particular, as shown in Example 5, even when wet snow was frozen, it was confirmed that the low temperature environment member of the present invention had an advantage over untreated glass.
As described above, the low temperature environment member of the present invention has hardly frost formation, hardly dew condensation, hardly icing property, and durability. It can be suitably used for products that require at least one of the icy properties.

  In addition, it was found that the members of Reference Examples 1 to 3 were all resistant to fingerprints and excellent in wipeability of fingerprints. The member of Comparative Example 1 was inferior in fingerprint adhesion and fingerprint wiping evaluation as compared with the Reference Example.

  The member for low-temperature environment of the present invention has sliding water repellency and excellent frost resistance, non-condensation property, and non-icing property. Therefore, traffic lights, automobiles, window glass, aircraft surface materials, air conditioner outdoor units, It can be suitably used for a non-frosting member, a non-condensing member, a non-icing member or the like used for a heat exchanger of a heat pump unit.

10 Jig 20 Sample 30 Iron plate 40 Load measuring device

Claims (9)

  A member formed by forming a sliding water-repellent layer on a substrate, the sliding water-repellent layer having a sea-island structure containing a perfluoro structure and a siloxane structure, and a height distribution curve of the surface of the sliding water-repellent layer A member for a low-temperature environment, wherein the height H showing the peak value of the frequency is 11.8 nm or less.   The low temperature environment member according to claim 1, wherein the height distribution curve has one inflection point on a side lower than the height H indicating the peak value. The height H indicating the peak value of the height distribution curve and the height H _{1 / 2L} on the lower elevation side of the height indicating 1/2 of the peak value of the height distribution curve are expressed by the following formula ( The member for low-temperature environments according to claim 1 or 2, satisfying the relationship of I).
H-H _{1 / 2L} ≦ 2.5nm (I) A height H indicating the peak value of the frequency of the height distribution curve and a height H _{1 / 2H} on the higher elevation side among the heights indicating one half of the peak value of the frequency of the height distribution curve. The member for low-temperature environments as described in any one of Claims 1-3 which satisfy | fills the relationship of following formula (II).
H _{1 / 2H} −H ≦ 3.0 nm (II) The height H indicating the peak value of the frequency of the height distribution curve and the height H _{1 / 3L} on the lower elevation side of the height indicating one third of the peak value of the frequency of the height distribution curve are: The member for low-temperature environments as described in any one of Claims 1-4 which satisfy | fills the relationship of following formula (III).
H-H _{1 / 3L} ≦ 3.0 nm (III) A height H indicating the peak value of the frequency of the height distribution curve, and a height H _{1 / 10L} on the lower elevation side among the heights indicating 1/10 of the peak value of the frequency of the height distribution curve. The member for low-temperature environments as described in any one of Claims 1-5 which satisfy | fills the relationship of following formula (IV).
H-H _{1 / 10L} ≦ 10.0nm (IV)   The member for low-temperature environments as described in any one of Claims 1-6 whose ratio of the island part in the said sea island structure is 20 to 50%.   The member for low-temperature environments as described in any one of Claims 1-7 whose said perfluoro structure and siloxane structure are polycondensation products of the alkoxysilane which has a perfluoro polyether structure. The member for low-temperature environments according to claim 8, wherein the polycondensation product of alkoxysilane having a perfluoropolyether structure is a polycondensation product of alkoxysilane having a perfluoropolyether structure and tetraalkoxysilane.