JP2010248071A - Highly washable glass molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a highly washable glass molded article in which the glass itself has stable and highly washable properties. <P>SOLUTION: A highly washable glass molded article in which the glass itself has stable and highly washable properties can be prepared when the glass composition of the glass molded article comprises 63-75 wt.% of SiO<SB>2</SB>, 7.9-16 wt.% of Al<SB>2</SB>O<SB>3</SB>, 14.6-17.5 wt.% of Na<SB>2</SB>O, 8-13 wt.% of B<SB>2</SB>O<SB>3</SB>, the density of the glass is not greater than 2.46 g/cm<SP>3</SP>, the mole ratio of Na<SB>2</SB>O/Al<SB>2</SB>O<SB>3</SB>is 2-4, the mole ratio of Na<SB>2</SB>O/SiO<SB>2</SB>is 0.21-0.3, the sum SiO<SB>2</SB>+Na<SB>2</SB>O+Al<SB>2</SB>O<SB>3</SB>is 83-93 wt.% and the weight to generate initial cracks measured by a micro Vickers hardness scale is not less than 200 g-weight. Further, the molded article thus prepared excels in water resistance, and alkali resistance, and has a low brittleness and a hardly decreasing strength. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a highly washable glass molded article having excellent antifouling properties and antifogging properties by maintaining a stable and highly hydrophilic surface.

  The surface of clean soda-lime glass immediately after production is highly hydrophilic (water contact angle 5 ° to 10 °) because water is hydrogen-bonded to silanol groups (Si—OH), but also adsorbs organic substances in the air or water. It is known that hydrophilicity decreases with the passage of time due to the influence of adhering organic substances and weathering / washing of glass.

If the hydrophilicity can be stably maintained over time, the antifouling property, the high cleaning property or the antifogging property can be maintained. For this reason, a technique for forming a hydrophilic treatment film on the glass surface has been proposed. For example, using the photocatalytic property of TiO ₂ , a glass surface (Patent Document 1) in which the glass surface always has high hydrophilicity, or an organic / inorganic film that exhibits water repellency in air but becomes hydrophilic in water and exhibits oil detergency. There is a hybrid film (Patent Document 2). In addition, there is a technique of forming a large amount of silanol groups (Si—OH), which are hydrophilic groups, on the surface after forming an SiO ₂ film on a glass substrate (Patent Document 3). This is because when the Al component is doped in the film in an amount of 0.1 to 20% by weight with respect to the Si component, the bond between the silanol group and water is stabilized, giving priority to the bond with other organic substances. The mechanism is not clear.
JP 2001-70801 A JP 2002-12450 A JP 2003-160360 A

The composition of general soda-lime glass used for glass molded products such as glass containers, figurines, and sheet glass is SiO ₂ : 70 to 73 wt%, CaO + MgO: 11 to 13 wt%, Na ₂ O + K ₂ O: 12 to 16.1 wt. %, Al ₂ O ₃ : 1 to ₂ wt%. Al ₂ O ₃ is known for improving water resistance, acid resistance, and alkali resistance (chemical durability), but if it is incorporated in a large amount, it tends to cause devitrification, and the glass must be melted at a high temperature. Therefore, it is limited to 2 wt% or less except for special glass that requires chemical durability. Moreover, the relationship between the amount of Al ₂ O ₃ in the glass composition and the hydrophilicity of the glass surface is not known at all.

The above prior art requires a coating process for forming a film on the surface of the glass substrate, which involves many manufacturing steps and high manufacturing costs. In addition, even in the above-described conventional film formation, the detergency and durability of oil droplets in water cannot be said to be sufficient. In particular, the present inventors have found that the TiO ₂ film exhibits strong hydrophilicity in the air, but does not perform its hydrophilic function in water, and the oil droplets stick to the substrate and the detergency of oils and fats is extremely poor. .

  In the present invention, the glass body itself has a stable and high cleaning property (the initial cleaning property is also high, with the lapse of time) for the purpose of improving the disadvantages of the conventional glass having a general composition and the disadvantages of the film formation method. The development of a highly detergency glass was also made as an issue.

(Configuration 1) In the present invention, SiO ₂ is 63 to 75 wt%, Al ₂ O ₃ is 7.9 to 16 wt%, Na ₂ O is 14.6 to 17.5 wt%, and B ₂ O ₃ is 8 to 13 wt%. And the density of the glass is 2.46 g / cm ³ or less, the molar ratio of Na ₂ O / Al ₂ O ₃ is 2-4, and the molar ratio of Na ₂ O / SiO ₂ is 0.21-0. 3 and the total of SiO ₂ + Na ₂ O + Al ₂ O ₃ is 83 to 93 wt%, and is made of glass having a crack initial load of 200 g or more using a micro Vickers hardness meter. Glass molded product.

In a soda-lime glass having a general composition used as a conventional glass tableware or plate glass, Si—O—Si cross-linked oxygen is also present on the surface, but it is known that this oxygen is not very hydrophilic. Actually, the contact angle of oil-in-water droplets of quartz glass composed only of Si—O—Si bridging oxygen is about 90 ° and is not large. Therefore, the present inventors first examined the relationship between the three-component glass composition and the oil-in-water contact angle, focusing on the Al—O—Si bridging oxygen in the Na ₂ O—Al ₂ O ₃ —SiO ₂ three-component glass. .

This type of glass is known to coordinate sodium to bridging oxygen because sodium is present at the charge compensation site when Al forms AlO ₄ tetrahedrons as oxygen as network forming ions. When the Na ₂ O / Al ₂ O ₃ molar ratio of this three-component glass is 1 or more, there are two types of alkali sites that coordinate to cross-linked oxygen and sodium to non-cross-linked oxygen, but the molar ratio approaches 1 Since non-crosslinked oxygen is reduced and only cross-linked oxygen is present in 1, the glass structure and physical properties have been studied, but the relationship with hydrophilicity is not known at all. As shown in the following reference example, the present inventor unexpectedly has a stable and large oil-in-water contact angle when Na ₂ O / Al ₂ O ₃ molar ratio = 2-4 and SiO ₂ is 63-75 wt%. I discovered that.

(Example of three-component glass)
In the 25Na ₂ O-25Al ₂ O ₃ -50SiO ₂ composition, since the Na ₂ O / Al ₂ O ₃ molar ratio = 1, there is theoretically no non-bridging oxygen, but the contact angle of oil-in-water droplets after 500 hot water washings is It was 132 °. This means that the hydrophilic group due to Al—O—Si bridging oxygen alone is stable but hydrophilicity is not so high. In addition, it is considered that the glass structure is not very open, and this affects the hydrophilicity due to the surface potential in order to limit the diffusion of sodium ions to the surface in the room temperature range. In the 25Na ₂ O—XAl ₂ O ₃ — (75-X) SiO ₂ composition, the contact angle of oil-in-water droplets after washing with hot water 500 times was 100 ° at a Na ₂ O / Al ₂ O ₃ molar ratio = 9. It was. This means that even when non-crosslinked oxygen is increased and a large amount of single silanol groups are generated on the surface, stable high hydrophilicity cannot be obtained. In addition, if the glass structure is open and sodium ions are eluted from the surface when washing is repeated, the surface layer has less sodium compared to the inside, and stable high hydrophilicity cannot be maintained due to the surface potential. Conceivable. Compared with this, in the same composition, when the Na ₂ O / Al ₂ O ₃ molar ratio was 2 to 4, the oil-in-water contact angle after washing with hot water 500 times was 150 °.

From these results, when the Na ₂ O / Al ₂ O ₃ molar ratio = 2-4, the present inventor found silanols caused by non-crosslinked oxygen in the vicinity of hydrophilic groups caused by Al—O—Si crosslinked oxygen. A plurality or a single group (Si—OH) was mixed, and an important and new finding that the surface structure in the vicinity of Al—O—Si formed by these contributed to stable high hydrophilicity was obtained. In the case of Na ₂ O / _Al 2 _{O 3} molar ratio = 2 to 4, and when SiO ₂ is 63～75Wt% to multiple SiO ₄ 4 tetrahedra adjacent AlO ₄ 4 tetrahedra non-bridging oxygen This new knowledge has been obtained because it exists. Further, if the stable high hydrophilicity is caused by the surface potential, the glass structure is moderately open, so that there is a necessary diffusivity to the surface of sodium, and there is a composition range with little elution. New findings were also obtained.

In order to confirm and apply the knowledge obtained with the ternary glass in practical soda-lime glass, Na ₂ O / SiO ₂ molar ratio = O. Under 5 fixed conditions, Na ₂ O / Al ₂ O ₃ molar ratio = 3 to 11 types of glass (NO.1-5), measured the oil-in-water contact angle when repeated hot water washing 500 times did. As a result, it was found that the smaller the Na ₂ O / Al ₂ O ₃ molar ratio, the larger the oil-in-water contact angle. (Table 1 and Figure 1)

Next, under the fixing conditions of Na ₂ O / Al ₂ O ₃ molar ratio = 11 and the same molar ratio = 3, each of 5 types (NO. _{2 of} Na ₂ O / SiO ₂ molar ratio = 0.2 to 0.6) -1 to NO.2-10) Glass oil contact angles were measured when the hot water washing was repeated 500 times (Table 2 and FIG. 2).

As a result, the Na ₂ O / Al ₂ O ₃ molar ratio = 3 has a higher oil droplet contact angle than the same molar ratio = 11, and even if Na ₂ O is small, the Na ₂ O / SiO ₂ molar ratio At 0.2, the oil-in-water contact angle exceeded 150 °.

Next, the above NO. For each of 2-6, soda lime 1, soda lime 2, borosilicate, quartz, and non-alkali glass (compositions are shown in Table 3), the relationship between the number of washings and the contact angle of oil-in-water droplets was examined. The result is shown in FIG. “Soda lime 1” and “soda lime 2” are soda lime glasses having a usual general composition, “borosilicate” is a borosilicate glass having a usual general composition, and “quartz” is composed only of SiO _2. Quartz glass, “non-alkali”, is a non-alkali glass of ordinary general composition. As is clear from FIG. 2-6 has remarkably stable and high cleanability as compared with other glasses.

  The present inventors have further studied from the above knowledge, and the glass having the composition 1 can stably maintain high hydrophilicity by itself (not only at the beginning of production but also after repeated washing). Therefore, it was discovered that high detergency can be stably maintained. Therefore, the glass molded product manufactured with this glass can maintain high cleaning property stably.

  In the present invention, the glass molded product is a glass tableware, a glass bottle for packaging, a glass container such as a household item such as a juicer, a mixer, a food processor, a mill, an ashtray, a vase or other glass decorative ornament, for construction, Plate covers such as for vehicles, cover glass, substrate glass, mirror glass, bent plate glass and other processed glass products, meter covers used as meter covers for water and electricity, fluorescent lamps, light bulbs and other lighting It is a glass molding for building materials such as glass and glass blocks and tiles.

The content of SiO ₂ is suitably 63~75wt%. If the amount of SiO ₂ is too small, the chemical durability is deteriorated. If the amount is too large, not only the meltability is deteriorated, but if the amount is outside this range, a stable high cleaning property cannot be obtained.

The content of Al ₂ O ₃ is suitably 7.9 to 16 wt%, preferably 2 ≦ Na ₂ O / Al ₂ O ₃ molar ratio ≦ 4. If the Al ₂ O ₃ content is too small, the chemical durability is deteriorated. If the Al ₂ O ₃ content is too large, not only the meltability is deteriorated, but if it is out of this range, a stable high cleaning property cannot be obtained.

The content of Na ₂ O is suitably 14.6 to 17.5 wt%, and preferably 0.21 ≦ Na ₂ O / SiO ₂ molar ratio ≦ 0.3. If the amount of Na ₂ O is too small, the meltability and detergency deteriorate, and if it is too large, the chemical durability deteriorates and weathering tends to occur. If it deviates from this range, stable high cleaning properties cannot be obtained.

B ₂ O ₃ is preferably contained in order to improve the meltability and weathering resistance. Although B ₂ O ₃ is a network forming oxide, to work as by cutting the mesh in a temperature of the softening point or higher flux and improving the meltability, when the temperature decreases Al ₂ O ₃ Similarly tetracoordinate This is effective for maintaining a high oil droplet contact angle. The content in the range of 8 to 13 wt% is preferable, and if it exceeds 13 wt%, there is a volatilization loss, and the damage to the furnace material is large, causing a practical problem.

By using the glass having the above composition, it is possible to obtain a stable and high detergency, and by setting B ₂ O ₃ to 8 to 13 wt%, the density of the glass is 2.46 g / cm ³ or less, and Micro Vickers The initial crack load using a hardness meter can be 200 g weight or more. By setting the density of the glass to 2.46 g / cm ³ or less, the crack initial load using the micro Vickers hardness meter becomes 200 g weight or more. The density of the glass can be easily adjusted by increasing or decreasing the content of Al ₂ O ₃ or B ₂ O ₃ , for example. That is, when the content of Al ₂ O ₃ is increased, the density is increased, and when the content of B ₂ O ₃ is increased, the density is decreased.

(Structure 2) The present invention also relates to the highly cleanable glass molded article according to Structure 1, wherein the contact angle of oil-in-water droplets after cleaning the glass surface 500 times is 140 ° or more. It is a molded product.

  Quantitative evaluation of high detergency was based on the measurement of oil-in-water contact angle, an oil-in-water repellency index commonly used in the field of detergency, for the mechanism (rolling up) in which oily soil is detached from the substrate in the washing liquid. . This evaluation method is used for cleaning performance evaluation of an organic-inorganic hybrid film on a glass substrate (Japanese Patent Laid-Open No. 2002-12450).

Oil-in-water contact angle (contact angle of oil-in-water droplets on the glass surface): θ
Interfacial tension of oil droplets and water: γow
Interfacial tension of glass surface and water: γgw
Interfacial tension between glass surface and oil droplets: γgo
Then, it is known that cos θ = (γgw−γgo) / γow holds. The hydrophilic glass surface decreases the interfacial tension γgw of the glass surface and water, so that the value of θ increases and oil droplets are easily detached from the glass surface. In addition, the lipophilic glass surface has the opposite effect, but is less dependent on the lipophilic glass composition. Therefore, when the oil droplets are placed on the glass surface and submerged in water and the contact angle of the oil-in-water glass at room temperature is measured, the hydrophilic stability and detergency of the glass surface can be evaluated simultaneously.

The contact angle of oil-in-water droplets of the present invention means that 25 μl of soybean oil droplets are dropped with a micropipette on the glass surface (free surface that melts into glass and comes into contact with air) and then placed horizontally in 20 ° C. water. This was measured by the hr method after taking a video and printing an image after being left for 30 seconds. The measurement after 30 seconds was because the oil droplets were stabilized in water.
Soybean oil (a reagent made by Hayashi Chemical) is also used as a model soil for a detergent test method for kitchen detergents (JIS K-3370), and its main components are linoleic acid and oleic acid.

In the present invention, the contact angle of the oil-in-water droplet after washing 500 times means that the glass surface is washed with hot water at 70 ° C. for 60 seconds and then cedared with hot water at 80 ° C. for 15 seconds. It means the oil-in-water contact angle measured after repeated times. Washing is done with 1 tank (70L) door type, vertical pressure spray rotary nozzle type commercial dishwasher (IWD JWD-6, hot water consumption 6.5L / time, washing water pressure 1-1.75kg / cm ² ) I went.

  In the present invention, the crack initial load using a micro Vickers hardness tester is the same sample as the indenter (2) of the micro Vickers hardness tester on the polished glass sample (1) surface as shown in FIG. On the other hand, the loading time is 15 seconds, 10 times each with an arbitrary load of 25 g to 2000 g, and the average value of the number of cracks generated 30 seconds after unloading is obtained. For example, as shown in FIG. The load W when the crack (4) occurs from any two of the four corners of the indentation (3). The measurement was performed at 20 ° C. in the atmosphere using an Akashi micro Vickers hardness meter.

  The initial crack load using a micro Vickers hardness tester is an indicator of the brittleness (brittleness) of the glass. That is, the greater the initial load, the lower the brittleness. The initial load of the glass constituting the glass molded article is desirably 200 g weight or more, more preferably 450 g weight or more. By making it low brittle, it is possible to reduce the occurrence of microcracks on the surface, which is the main cause of the decrease in strength of the glass, and to prevent the decrease in strength.

By setting the glass density to 2.46 g / cm ³ or less in the glass composition of Configuration 1 or 2, the initial crack load using a micro Vickers hardness meter is 200 g weight or more. The density of the glass can be easily adjusted by increasing or decreasing the content of, for example, Al ₂ O ₃ , B ₂ O ₃ or MgO. That is, when the content of Al ₂ O ₃ is increased, the density is increased, and when the content of B ₂ O ₃ or MgO is increased, the density is decreased.

  The glass molded article of the present invention has an excellent and stable high cleaning property that can maintain the oil repellency in water in a high state even after the glass itself has been repeatedly washed many times as well as at the beginning of production. Therefore, a coating process is unnecessary, it can manufacture by the same manufacturing process as normal soda-lime glass, and a manufacturing cost does not become high. In addition to such stable and high detergency, there is an effect of showing high water resistance and alkali resistance. Furthermore, it has the effect of exhibiting low brittleness as well as stable high detergency.

It is an explanatory view showing the relationship Na ₂ O / _Al 2 _{O 3} molar ratio and oil-in-water contact angle. It is an explanatory view showing the relationship Na ₂ O / SiO ₂ molar ratio and oil-in-water contact angle. It is explanatory drawing of the kind of glass and an oil-in-water contact angle. It is explanatory drawing of the crack initial load using the micro Vickers hardness meter. It is explanatory drawing of the alkali erosion weight decreasing rate of an Example, the reference example 2, and the comparative example 1. FIG. It is explanatory drawing of the relationship between a crack initial load and density.

The glass in the present invention has a Na ₂ O / Al ₂ O ₃ molar ratio of 2 to 4, a Na ₂ O / SiO ₂ molar ratio of 0.21 to 0.3, and SiO ₂ + Na ₂ O + Al _2. It is desirable that the total of O ₃ is 83 to 93 wt%. By setting the molar ratio of each component in this way, it is possible to obtain a more stable and high detergency. If the molar ratio of Na ₂ O / Al ₂ O ₃ is too small, the meltability is deteriorated because Na ₂ O is small, and if it is too large, the detergency is lowered because Al ₂ O ₃ is small, and the water resistance of the glass is also low. descend.

Glass in the present invention may contain a TiO ₂ 0~9wt%. Addition of TiO ₂ improves the meltability, but if it exceeds 9 wt%, the cleaning properties are lowered, which is not preferable.

In the glass of the present invention, the contact angle of oil-in-water droplets after washing the glass surface 500 times can be easily set to 140 ° or more. For example, a test glass is produced with the desired composition described in the constitution 1, the oil-in-water contact angle after washing 500 times is measured, and if it is less than 140 °, Al ₂ O ₃ or By making adjustments such as slightly increasing the amount of B ₂ O ₃ or slightly decreasing the amount of Na ₂ O, the oil-in-water contact angle after washing 500 times can be easily made 140 ° or more.

  When the contact angle of the initial oil-in-water droplet is 160 ° or more, it is observed that the oil droplet is spontaneously detached (rolling up) from the glass surface within 30 seconds. When the contact angle of the oil-in-water droplet after 30 seconds is 140 ° or more and less than 160 °, the oil droplet is observed to be spontaneously detached (rolling up) from the glass surface with a weak water flow. It has excellent antifouling properties such as self-cleaning with rainwater. When the contact angle of the oil-in-water droplet after 30 seconds is less than 140 °, it is observed that a part of the oil droplet remains on the surface even if the oil droplet is detached with a water flow. Therefore, if the oil-in-water contact angle is 140 ° or more, it has a suitable high detergency.

Moreover, the glass in this invention can set the crack initial load using a micro Vickers hardness meter to 200 g because the density of glass is 2.46 g / cm < ³ > or less.

In Table 4, the glass composition of the glass tableware of an Example is represented. In Reference Examples 1 and 2, B ₂ O ₃ is less than 8 wt%, CaO or MgO is blended, and the others are the same as the glass composition in the present invention. Comparative Example 1 shows a composition of a conventional general glass tableware, and Comparative Example 2 shows an example of a three-component composition for glass structure research.

(Evaluation of high detergency)
As is apparent from Table 4, in the example, the contact angle of the oil-in-water droplet after washing 500 times is 140 ° or more (152 °), and the oil droplet in water naturally desorbs from the glass surface with a weak water flow. Even after repeated cleaning, stable high cleaning performance is ensured. On the other hand, in Comparative Examples 1 and 2, the oil-in-water contact angle after washing 500 times is greatly inferior to that of the Examples, and does not have a stable washability.

(Alkali resistance evaluation)
A sample of 40 mm X 40 mm X 5 mm in shape is immersed in 100 mL of an alkaline detergent solution (washmate EP) 0.2% solution (PH = 10.5) at 65 ° C. for 24 hours, and the sample is taken out, washed with water, dried and measured for weight loss. One cycle was repeated for 12 cycles. The result is shown in FIG. Further, “Alkaline erosion weight reduction rate (12 days)” after 12 cycles is shown in Table 4. The examples are remarkably superior in alkali resistance compared to the comparative examples (weight reduction rate is about 1/3), and there is no fear of whitening due to the use of a dishwasher.

(Evaluation of crack initial load using micro Vickers hardness tester)
The glass poured out after melting the crucible was gradually cooled at 560 ° C., cut and polished to prepare a 40 mm square sample with a thickness of 5 mm, and the initial crack load was determined with a micro Vickers hardness meter. The initial crack load of ordinary soda-lime glass is 50 g weight to 100 g weight, but the reference example 2 is 450 g weight, and the example is 250 g weight, which is 3 to 5 times or more. FIG. 6 shows the relationship between density and crack initial load. Reference Example 2 cracks initial load becomes 450g weight by a 2.45 g / cm ³ density, examples cracks initial load becomes more heavy 200g by the density 2.46 g / cm ³ or less. When the density is 2.47 g / cm ³ or more, the crack initial load is low. In the practical use of glass, it is known that a minute crack on the surface serves as a starting point of breakage. Therefore, it is difficult for the crack to occur, which means that brittleness is small. The density was measured with a high-precision electronic hydrometer (JIS-compliant Archimedes principle method).

(Evaluation of hydrophilicity / antifogging)
For Reference Example 1 and Comparative Example 1, the contact angle of water droplets in air after 7 days of standing (after 7 days of washing with hot water) was measured. Reference Example 1 had a value smaller than 10 °, and Comparative Example 1 was 20 °. Thereby, it was confirmed that Reference Example 1 is superior in hydrophilicity and antifogging property as compared with general soda-lime glass.

(Evaluation of meltability)
For Examples, Reference Examples 1 and 2 and Comparative Example 1, high-temperature viscosity measurement (LOGη = 2 (° C.) and LOGη = 3 (° C.)) was performed to evaluate the meltability. As a result, as shown in Table 4, it was confirmed that the glass of the example and the reference example had a melting property almost comparable to that of Comparative Example 1 (ordinary soda lime glass).

1 Glass sample 2 Indenter 3 Indentation 4 Crack

Claims (2)

The SiO ₂ 63~75wt%, 7.9~16wt% of _Al 2 _{O 3, 14.6~17.5wt%} of Na _{2 O,} a B 2 _{O 3} containing 8-13 weight%, the density of the glass 2 a is .46g / cm ³ or _less, the molar ratio of Na 2 O / _Al 2 _{O 3} is _2-4, the molar ratio of Na ₂ O / SiO 2 is from 0.21 to 0.3, and, SiO ₂ A high detergency glass molded article characterized by comprising a glass having a total of + Na ₂ O + Al ₂ O ₃ of 83 to 93 wt% and an initial crack load of 200 g or more using a micro Vickers hardness tester.   The highly washable glass molded article according to claim 1, wherein the contact angle of the oil-in-water droplets after washing the glass surface 500 times is 140 ° or more.