ULTRAVIOLET AND INFRARED RADIATION ABSORBING GLASS

Abstract: An ultraviolet and infrared radiation absorbing glass is disclosed, which has a bronze or neutral gray tint, a low ultraviolet transmission, and a low total solar energy transmission and is suitable for use as a window glass for motor vehicles or buildings. The glass comprises, in % by weight: basic glass components comprising 65 to 80 % SiO2, 0 to 5 % B2O3, 0 to 5 % Al2O3, 0 to 10 % MgO, 5 to 15 % CaO, 10 to 18 % Na2O, and 0 to 5 % K2O, provided that the sum of MgO and CaO is 5 to 15 % and the sum of Na2O and K2O is 10 to 20 %; coloring components comprising 0.20 to 0.30 % total iron oxide (T-Fe2O3) in terms of Fe2O3, 0.65 to 1.1 % CeO2, 0.35 to 1.1 % TiO2, 0.001 to 0.005 % CoO, and 0.0003 to 0.0015 % Se; and an additional component comprising 0.02 to 0.30 % SO3, wherein 20.5 to 25 % of said T-Fe2O3 is FeO in terms of Fe2O3.

Description: DESCRIPTION ULTRAVIOLET AND INFRARED RADIATION ABSORBING GLASS TECHNICAL FIELD The present invention relates to an ultraviolet and infrared radiation absorbing glass having a bronze or neutral gray tint. TECHNICAL BACKGROUND In order to meet the demand for protection of interior trim of automobiles against deterioration, which has been increasing with the recent trend to luxury of the interior trim, and to reduce the load of air conditioning, a glass having ultraviolet and infrared radiation absorbing power has recently been proposed as an automotive window glass. For example, a green tinted glass containing a relatively large amount of Fe 2 0 3 and having enhanced heat radiation and ultraviolet radiation absorbing power has been developed for automotive use. In glasses having a bronze or brown tint, the ultraviolet radiation absorbing power thereof is enhanced by using Ce0 2 and Ti0 2 at a lower Fe 2 0 3 content than the green tinted glass. For example, the heat radiation absorbing glass having a bronze tint disclosed in JP-A-6-40741 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") comprises, in % by weight, basic glass components comprising 68 to 74% Si0 2 , 0.1 to 3% A1 2 0 3 , 2 to 4.5% MgO, 8 to 11% CaO, 11.5 to 16% Na 2 0, 0.5 to 3.0% K 2 0, and 0.1 to 0.4% S0 3 , provided that the sum of Si0 2 and A1 2 0 3 is 68 to 74%, the sum of CaO and MgO is 11 to 15%, and the sum of Na 2 0 and K 2 0 is 12 to 17%, and coloring components comprising 0.13 to 0.55% total iron oxide in terms of Fe 2 0 3 , 0.2 to 0.6% Ce0 2 , and 0.15 to 0.45% Ti0 2 , and further comprises 0.3 to 14 ppm CoO and 5 to 20 ppm Se. This glass has a reduction rate (Fe 2+ /Fe 3+ ) of 17 to 55%. The ultraviolet radiation absorbing colored glass disclosed in JP-A-6-345482 is a brown tinted glass which comprises, in % by weight, 65 to 75% Si0 2 , 0.1 to 5% A1 2 0 3 , 1 to 6% MgO, 5 to 15% CaO, 10 to 18% Na 2 0, 0 to 5% K,0, 0.05 to 1.0% S0 3 , 0.2 to 1.5% Ce0 2 , 0 to 1.0% Ti0 2 , 0 to 0.0015% CoO, 0.0002 to 0.0012% Se, and 0.2 to 0.4% Fe 2 0 3 , wherein 3 to 15% of the total iron oxide in terms of Fe 2 0 3 is FeO. The ultraviolet radiation absorbing colored glass disclosed in JP-A-6-345483 is a glass which comprises, in % by weight, 65 to 75% Si0 2 , 0.1 to 5% A1 2 0 3 1 to 6% MgO, 5 to 15% CaO, 10 to 18% Na 2 0, 0 to 5% K 2 0, 0.05 to 1.0% S0 3 , 0.4 to 1.0% Ce0 2 , 0 to 1.0% Ti0 2/ 0.0018 to 0.0030% CoO, 0.0001 to 0.0010% Se, and 0.1 to 0.3% Fe 2 0 3 , wherein 3 to 20% of the total iron oxide in terms of Fe 2 0 3 is FeO. Furthermore, the gray glass composition disclosed in JP- A-8-48540 is a colored glass composition having a dull gray tint which comprises, in % by weight, 66 to 75% Si0 2 , 0 to 5% A1 2 0 3 , 0 to 5% MgO, 5 to 15% CaO, 10 to 20% Na 2 0, 0 to 5% K 2 0, 0.0003 to 0.0050% CoO, 0.0001 to 0.0015% Se, and 0.30 to 0.70% Fe 2 0 3 (total iron oxide), with the FeO content being up to 0.21%, and which may further contain up to 2.0% Ce0 2 , V 2 0 5 , Ti0 2 , and Mo0 3 . The above-described conventional ultraviolet and infrared radiation absorbing glasses have an ultraviolet radiation absorbing power imparted by Fe 2 0 3 , Ce0 2 , and TiO, and by interactions among them. However, in the glasses having a bronze or neutral gray tint obtained by using the coloration of Se, the Fe 2 0 3 content must be reduced to a relatively low level in order to maintain the pink coloration of Se. Consequently, it has been difficult to achieve both a bronze or neutral gray tint and high ultraviolet radiation absorbing power. That is, there has been the following problems. When the Ti0 2 content is increased, the glass tends to be yellowish. Even when the Ce0 2 content is increased, the coloration of Se is sometimes insufficient depending on the oxidation and reduction state of the glass, so that the ultraviolet radiation absorbing power is not effectively increased. This kind of glasses further have a drawback that an increase in the proportion of FeO in total iron oxide tends to result in the above-described problems concerning color tint. In the case of ordinary glasses having a bronze or neutral gray tint and not having high ultraviolet radiation absorbing power, an increase in FeO proportion may impair the infrared radiation absorbing power thereof. The present invention has been made in the light of the above-described problems associated with the conventional techniques . An object of the present invention is to provide an ultraviolet and infrared radiation absorbing glass having a bronze or neutral gray tint and having especially high ultraviolet radiation absorbing power and satisfactory infrared radiation absorbing power. DISCLOSURE OF THE INVENTION The present invention provides an ultraviolet and infrared radiation absorbing glass comprising, in % by weight: basic glass components comprising 65 to 80% Si0 2 , 0 to 5% B 2 0 3 , 0 to 5% A1 2 0 3 , 0 to 10% MgO, 5 to 15% CaO, 10 to 18% Na 2 0, and 0 to 5% K 2 0, provided that the sum of MgO and CaO is 5 to 15% and the sum of Na 2 0 and K 2 0 is 10 to 20%; coloring components comprising 0.20 to 0.30% total iron oxide (T-Fe 2 0 3 ) in terms of Fe 2 0 3 , 0.65 to 1.1% Ce0 2 , 0.35 to 1.1% Ti0 2 , 0.001 to 0.005% CoO, and 0.0003 to 0.0015% Se; and an additional component comprising 0.02 to 0.30% S0 3 , wherein 20.5 to 25% of said T-Fe 2 0 3 is FeO in terms of Fe 2 0 3 . PREFERRED EMBODIMENTS OF THE INVENTION The ultraviolet and infrared radiation absorbing glass described above preferably contains 0.0005 to 0.005% by weight NiO. The ultraviolet and infrared radiation absorbing glass preferably contains 0.20 to 0.90% by weight La 2 0 3 . The ultraviolet and infrared radiation absorbing glass of the present invention preferably has such optical characteristics that the visible light transmission as measured with the CIE standard illuminant A of 70% or more and the total solar energy transmission as measured in a wavelength region of from 300 to 2,100 nm is less than 72%, when the thickness thereof is from 3.25 to 6.25 mm. Furthermore, the ultraviolet and infrared radiation absorbing glass of the present invention preferably has such optical characteristics that the dominant wavelength thereof as measured with the CIE standard illuminant C is 572 to 580 nm and the total sunlight ultraviolet transmission defined in ISO 9050 as measured in a wavelength region of from 297.5 to 377.5 nm is less than 12%, when the glass has a thickness of 3.25 to 6.25 mm. The reasons for limitations of the composition of the ultraviolet and infrared radiation absorbing glass according to the present invention are explained below. Hereinafter, all percents used for component amounts are by weight. The composition of the glass is based on a glass composition suitable for forming by a float process. Si0 2 is a main component forming a skeleton of glass. If the Si0 2 content is less than 65%, the glass has poor durability. If the Si0 2 content exceeds 80%, the glass is difficult to melt. Although B 2 0 3 is a component generally used for improving glass durability or as a melting aid, it also functions to enhance ultraviolet absorption. If the B 2 0 3 content exceeds 5%, not only the decrease of transmission in the ultraviolet region extends to the visible region, often resulting in a yellowish tint, but also troubles arise in glass forming due to vaporization of B 2 0 3 , etc. Accordingly, the upper limit of the B 2 0 3 content should be 5%. A1 2 0 3 serves to improve glass durability. If the A1 2 0 3 content exceeds 5%, the glass is difficult to melt. From the standpoint of obtaining a glass having moderately improved durability while preventing the glass from having an elevated melting temperature, the preferred range of A1 2 0 3 content is from 0.1 to 2%. MgO and CaO both are used for improving glass durability and for regulating a liquidus temperature and viscosity of the glass during forming. If the MgO content exceeds 10%, the liquidus temperature rises. If the CaO content is less than 5% or higher than 15%, the liquidus temperature rises. If the total content of MgO and CaO is less than 5%, the durability of the resulting glass deteriorates. If the total content thereof exceeds 15%, the liquidus temperature rises. Na 2 0 and K 2 0 are used as glass melting accelerators. If the Na 2 0 content is less than 10% or if the total content of Na 2 0 and K 2 0 is less than 10%, the effect of melting acceleration is poor. If the Na 2 0 content exceeds 18% or if the total content of Na 2 0 and K 2 0 exceeds 20%, glass durability is decreased. K 2 0 further has the effect of enhancing the pink coloration of Se and, at the same time, increasing the ultraviolet radiation absorbing power. It is undesirable to incorporate K 2 0 in an amount exceeding 5%, because it is more expensive than Na 2 0. Iron oxide in a glass is present in the forms of Fe 2 0 3 (Fe 3+ ) and FeO (Fe 2+ ) . FeO is a component which serves to enhance infrared radiation absorbing power, while Fe 2 0 3 is a component which serves to enhance ultraviolet radiation absorbing power together with Ce0 2 and Ti0 2 . If the amount of the total iron oxide (T-Fe 2 0 3 ) is too small, the infrared radiation absorbing power and ultraviolet radiation absorbing power are low. If the amount thereof is too large, the visible light transmission is decreased. Therefore, the preferred range of the total iron oxide content is from 0.20 to 0.30%. If the amount of FeO is too small, the infrared radiation absorbing power is decreased. If the amount thereof is too large, the visible light transmission is decreased. Therefore, the preferred range of FeO amount in terms of Fe 2 0 3 is from 20.5 to 25% of the total iron oxide. In the present invention, a relatively low total iron oxide content and a relatively high FeO content are employed mainly for the purpose of enhancing the infrared radiation absorbing power while maintaining a high visible light transmission. Those ranges of total iron oxide content and FeO content are suitable for this purpose. Ce0 2 , which is an essential component in the present invention, serves to enhance ultraviolet radiation absorbing power. Ce0 2 in a glass is present in the form of Ce 3+ or Ce 4+ . In particular, Ce 3+ shows reduced absorption in the visible light region and is effective in ultraviolet absorption. If the Ce0 2 content is too high, the glass shows enhanced absorption in a shorter-wavelength part of the visible light region and is hence yellowish. In addition, since the cerium oxide used as a raw material serves as an oxidizing agent, it is difficult to maintain a high FeO/T-Fe 2 0 3 ratio when a glass having a high Ce0 2 content is melted. Therefore, the Ce0 2 content is preferably from 0.65 to 1.1%. Ti0 2 , which is an essential component in the present invention, serves to enhance ultraviolet radiation absorbing power particularly by the interaction with FeO. If the Ti0 2 content is too high, the glass tends to be yellowish. In the present invention, a high FeO/T-Fe 2 0 3 ratio is used with a small total iron oxide amount and, in order to facilitate reduced melting necessary for attaining the Fe0/T-Fe 2 0 3 ratio, a relatively small Ce0 2 amount in the range of from 0.65 to 1.1% is used, as stated above. Therefore, from the standpoint of compensating for the resultant insufficiency of ultraviolet radiation absorbing power, the Ti0 2 content is preferably from 0.35 to 1.1%. CoO is a component for forming a bronze or neutral gray tint by the coexistence thereof with Se. If the CoO content is less than 0.001%, the desired tint cannot be obtained. If the CoO content exceeds 0.005%, the visible light transmission is decreased. Se is a component for obtaining a bronze or neutral gray tint due to its pink coloration in combination with the complementary color of CoO. If the Se content is less than 0.0003%, the desired tint cannot be obtained. If the Se content exceeds 0.0015%, the visible light transmission is decreased. S0 3 is a component which has come into the glass mainly from a sulfuric acid salt or the like used as a refining agent. In order to obtain an FeO/T-Fe 2 0 3 ratio in the range specified above, the amount of a sulfuric acid salt, e.g., salt cake, is regulated so as to result in an S0 3 content in the glass of from 0.02 to 0.30%. If the S0 3 content is less than 0.02%, refining is insufficient. If the S0 3 content exceeds 0.30%, the coloration of Se is weakened disadvantageously. NiO is a component for obtaining a neutral gray tint. If the NiO content is too high, the visible light transmission is decreased. Therefore, it should be used in an amount of 0.005% or less. La 2 0 3 not only is effective in decreasing the viscosity of the molten glass and accelerating glass melting, but also improves the chemical durability of the glass, such as water resistance. The addition of La 2 0 3 to a glass containing Fe 2 0 3 and Ce0 2 is also effective in decreasing the ultraviolet transmission. If the La 2 0 3 content is less than 0.20%, those effects are insufficient. Since La 2 0 3 is an expensive raw material, the content thereof is preferably not higher than 0.90%. La 2 0 3 may be added in the form of a raw material containing La 2 0 3 in a high concentration. However, such a raw material is costly because it needs to be refined. From the standpoint of attaining a decreased raw-material cost, it is therefore preferred to add La 2 0 3 in the form of a mixture of La 2 0 3 and Ce0 2 occurring simultaneously, without separating these, or in the form of an impurity remaining in Ce0 2 having a low degree of purification. In the latter case, oxides of other rare earth elements, such as Pr 2 0 3 and Nd 2 0 3 , also come as impurities into the glass in slight amounts. However, such impurities may be contained as long as this is not counter to the spirit of the invention. The glass having the above-described composition of the present invention may further contain at least one of ZnO, MhO, V 2 0 5 , and Mo0 3 in a total amount of 0 to 1%, as long as these ingredients are not counter to the spirit of the invention. Of those optional ingredients, ZnO, which is apt to generate upon glass melting in a reducing atmosphere, is effective in preventing the formation of nickel sulfide causative of spontaneous fracture of a glass. MnO, V 2 0 5 , and Mo0 3 in the glass each serves as an ultraviolet absorbing component. These components can be used according to their degrees of ultraviolet absorption for the fine control of a bronze or neutral gray tint. The present invention will be described in more detail by reference to the following Examples. It should however be understood that the invention is not construed as being limited thereto. EXAMPLES In order to obtain given glass compositions, ingredients were suitably mixed which consisted of silica sand, dolomite, limestone, soda ash, potassium carbonate, boron oxide, salt cake, ferric oxide, titanium oxide, cerium oxide, cobalt oxide, sodium selenite, nickel oxide, lanthanum oxide, and a carbonaceous material as a reducing agent. The resulting raw materials each was melted at 1,500°C for 4 hours in an electric furnace. Each molten glass was then cast on a stainless-steel plate and annealed to obtain a glass plate having a thickness of about 7 mm. The glass plates obtained were polished so as to have thicknesses of 3.5, 4, and 5 mm. Optical characteristics of the samples thus obtained were measured. The optical characteristics included visible light transmission (YA) measured with the CIE standard illuminant A, total solar energy transmission (TG) , ultraviolet radiation transmission (Tuv) defined in ISO 9050, dominant wavelength (Dw) and excitation purity (Pe) both measured with the CIE standard illuminant C, and L * , a * , and b * defined in CIE. The results obtained in the Examples are shown in Tables 1 to 5, which show the concentration of each component in each sample obtained and the values of optical characteristics for each sample. All values of concentration given in the Tables are % by weight, and the values of the ratio of FeO in terms of Fe 2 0 3 to T-Fe 2 0 3 are also given in %. Table 1 Exampl 1 Example ?. Example 3 Composition (wt%) SiO, 70.6 70.7 70.9 B 2 0 3 - - - A1 2 0 3 1 1..44 1 1..44 1 1..44 MgO 4 4..00 4 4..00 4 4..00 CaO 8 8..00 8 8..00 8 8..00 Na 2 0 1 .33..00 1 133..00 1 133..00 K 2 0 0 0..77 0 0..77 0 0..77 Se 0 0..00001111 0 0..00000099 0 0..0000111 CoO 0 0..00002200 0 0..00002255 0 0..0000225 Ce0 2 1 1..0000 1 1..1100 0 0..8855 Ti0 2 1 1..0000 0 0..9900 0 0..9900 NiO - - - La 2 0 3 - - - T-Fe 2 0 3 0.27 0.23 0.25 FeO 0.057 0.050 0.050 FeO/T-Fe : 0 3 (%) 23.3 24.1 22.4 S0 3 0.05 0.07 0.08 Optical Characteris tics Thickness (mm) 3.5 3.5 3.5 YA (%) 7 733..55 7 744..00 7 744..00 TG (%) 6 677..88 6 699..88 6 699..88 L * 8 888..44 8 888..66 8 888..77 a * - -00..8888 - -00..7744 - -00..8833 b * 7 7..0022 6 6..5500 4 4..5500 λd 5 57744 5 57766 5 57733 Pe (%) 7 7..1100 6 6..3300 4 4..4499 T v (%) 9.2 10.3 11.9 Tabl« ?r 2 Example 4 Example 5 Example 6 Composition (wt%) Si0 2 70.9 70.8 70.8 B 2 0 3 - - - A1 2 0 3 1.4 1.6 1.6 MgO 4.0 4.0 4.0 CaO 8.0 8.0 8.0 Na 2 0 13.0 13.0 13.0 K 2 0 0.7 0.8 0.8 Se 0.0011 0.0011 0.0011 CoO 0.0025 0.0020 0.0020 Ce0 2 0.85 0.85 0.85 Ti0 2 0.90 0.70 0.70 NiO La,0, T-Fe 2 0 3 0.25 0.25 0.25 FeO 0.047 0.056 0.046 FeO/T-Fe 2 0 3 (%) 20.7 24.8 20.5 S0 3 0.09 0.05 0.09 Optical Characteristics Thickness (mm) 3.5 4.0 4.0 YA (%) 74.2 72.7 74.0 TG (%) 70.7 66.8 69.3 L * 88.5 88.0 88.1 a * -0.70 -0.73 -0.36 b * 4.92 5.96 5.78 λd 576 575 576 Pe (%) 5.05 6.18 5.91 Tuv ( % ; 11.4 11.4 11.4 Table 3 Example 7 Example 8 Example 9 Example 10 Composition (wt%) Si0 2 71.0 70.6 71.4 70.0 B 2 0 3 - - - 2.0 A1 2 0 3 1.6 1.6 1.6 1.4 MgO 4.0 4.0 4.0 3.9 CaO 8.0 8.0 8.0 8.0 Na 2 0 13.0 13.0 13.0 12.8 K 2 0 0.8 0.8 0.8 0.7 Se 0.0011 0.0009 0.0007 0.0007 CoO 0.0015 0.0027 0.0012 0.0012 Ce0 2 0.85 0.70 0.65 0.65 Ti0 2 0.50 1.10 0.35 0.35 NiO La 2 0 3 T-Fe 2 0 3 0.25 0.25 0.25 0.25 FeO 0.047 0.04? 0.055 0.054 FeO/T-Fe 2 0 3 (%) 20.7 21.3 24.4 24.0 S0 3 0.09 0.09 0.07 0.07 Optical Characteristics Thickness (mm) 5.0 4.0 5.0 4.0 YA (%) 72.0 71.9 72.2 73.4 TG (%) 65.8 67.6 65.1 67.1 L * 87.6 87.4 87.7 88.2 * a -0.45 -0.51 -0.24 -0.31 b * 6.61 6.33 4.67 5.26 λd 576 576 576 576 Pe (%) 6.93 6.62 5.52 5.35 Tuv (%) 10.2 10.3 11.9 10.3 Table 4 Example 11 Example 1 ?. Example 1 Example 14 Composition (wt%) Si0 2 71.0 71.1 70.6 70.7 B 2 0 3 - A1 2 0 3 1.4 1.4 1.8 2.0 MgO 4.0 4.0 4.0 4.0 CaO 8.0 8.0 8.0 8.0 Na 2 0 13.0 13.0 13.0 13.0 K 2 0 0.7 0.7 1.0 1.1 Se 0.0008 0.0006 0.0011 0.0008 CoO 0.0035 0.0018 0.0015 0.0011 Ce0 2 0.65 0.65 0.85 0.65 Ti0 2 1.10 0.90 0.50 0.35 NiO - - 0.0010 0.0020 La 2 0 3 - - - - T-Fe 2 0 3 0.20 0.30 0.25 0.25 FeO 0.045 0.056 0.049 0.049 FeO/T-Fe 2 0 3 (%) 25.0 20.7 21.8 21.8 S0 3 0.06 0.10 0.08 0.0E Optical Characteristics Thickness (mm) 5.0 3.5 5.0 5.0 YA (%) 72.2 73.3 71.5 71.5 TG (%) 66.1 68.0 65.1 64.9 L * 87.9 88.5 87.8 87.7 a * -0.43 -0.42 -0.39 -0.17 b * 5.15 6.52 6.97 5.21 λd 576 576 576 576 Pe (%) 6-11 6.70 6.91 5.40 Tuv (%) 9.9 11.8 9.8 11.9 Table 5 Example 15 Example 16 Example 17 Composition (wt%) Si0 2 70.0 70.6 71.1 B 2 0 3 A1 2 0 3 1.4 1.4 1.6 MgO 4.0 4.0 4.0 CaO 8.0 8.0 8.0 Na 2 0 13.0 13.0 13.0 K 2 0 0.7 0.7 0.8 Se 0.0009 0.0011 0.0009 CoO 0.0025 0.0020 0.0012 Ce0 2 1.10 0.85 0.65 Ti0 2 0.90 0.70 0.35 NiO La 2 0 3 0.70 0.51 0.30 T-Fe 2 0 3 0.25 0.25 0.24 FeO 0.051 0.053 0.052 FeO/T-Fe 2 0 3 ( % ) 22.6 23.5 24.1 S0 3 0.08 0.07 0.06 Optical Characteristics Thickness (mm) 3.5 4.0 5.0 YA (%) 74.0 72.7 74.1 TG (%) 69.8 66.8 65.0 L * 88.6 88.0 88.7 a * -0.74 -0.73 -0.23 b * 6.50 5.96 4.82 λd 576 575 576 Pe (%) 6.30 6.18 5.03 Tuv (%) 10.3 11.4 11.9 The samples obtained in Examples 1 to 12, shown in Tables 1 to 4, each was within the scope of claim 1. Specifically, each sample had a composition which contained 0.20 to 0.30% total iron oxide in terms of Fe 2 0 3 , 0.65 to 1.1% Ce0 2 , 0.35 to 1.1% Ti0 2 , 0.001 to 0.005% CoO, 0.0003 to 0.0015% Se, and 0.02 to 0.30% S0 3 and in which the proportion of FeO in terms of Fe 2 0 3 to T-Fe 2 0 3 was from 20.5 to 25%. Of the samples obtained in the above Examples, the sample of Example 10 was a glass containing 2% B 2 0 3 so as to have a reduced ultraviolet transmission and improved glass durability. The samples obtained in Examples 13 and 14, which were within the scope of the preferred embodiment, contained NiO so as to have a controlled tint. The samples obtained in Examples 15 to 17, which were within the scope of the further preferred embodiment, contained La 2 0 3 so as to have a reduced ultraviolet transmission and improved chemical durability. The samples obtained in the Examples each was a bronze or neutral gray-tinted ultraviolet and infrared radiation absorbing glass having a visible light transmission as measured with the CIE standard illuminant A of 70% or more, a total solar energy transmission of less than 72%, a dominant wavelength and an excitation purity as measured with the CIE standard illuminant C of 572 to 580 nm and less than 8%, respectively, and an ultraviolet transmission defined in ISO 9050 of less than 12%. COMPARATIVE EXAMPLES Comparative Examples to the present invention are shown in Table 6. Table 6 Comparative Comparative Comparative Example 1 Example 2 Example 3 Composition (wt5 Si0 2 71.8 70.9 70.8 B 2 0 3 A1 2 0 3 1.7 1.4 1.6 MgO 3.6 4.0 4.0 CaO 7.0 8.0 8.0 Na 2 0 13.0 13.0 13.0 K 2 0 0.8 0.7 0.8 Se 0.0010 0.0008 0.0011 CoO 0.0025 0.0005 0.0020 Ce0 2 0.90 0.41 0.00 Ti0 2 1.06 0.31 2.00 NiO - - - La 2 0 3 - - - T-Fe 2 0 3 0.18 0.40 0.27 FeO 0.025 0.079 0.062 FeO/T-Fe 2 0 3 (%) 15.6 21.8 25.6 S0 3 0.09 0.08 0.06 Optical Characteristics Thickness (mm) 5.0 4.0 3.5 YA (%) 73 .5 73 .4 71.5 TG (%) 73 .0 59, .5 66.1 88 .2 87, .8 87.2 0. .23 -0, .56 -0.22 4. .81 8. ,56 8.10 λd 578 574 577 Pe (%) 5. ,11 8. 40 8.55 Tuv (%) 9.0 16.7 21.4 The sample obtained in Comparative Example 1 was outside the scope of the present invention with respect to T-Fe 2 0 3 content and FeO/T-Fe 2 0 3 ratio. This sample had a total solar energy transmission of 72% or more. The sample obtained in Comparative Example 2 was outside the scope of the present invention with respect to T-Fe 2 0 3 , Ce0 2 , Ti0 2 , and CoO contents, while the sample obtained in Comparative Example 3 was outside the scope of the present invention with respect to Ce0 2 and Ti0 2 contents and FeO/T-Fe 2 0 3 ratio. The samples of Comparative Examples 2 and 3 each had an excitation purity of 8% or more and an ultraviolet transmission defined in ISO 9050 of 12% or more. Thus, the glasses of Comparative Examples 1 to 3 each failed to combine a bronze or neutral gray tint, a low total solar energy transmission, and a low ultraviolet transmission. As apparent from the Examples and Comparative Examples given above, the glass of the present invention is an excellent ultraviolet and infrared radiation absorbing glass which combines a bronze or neutral gray tint, a low ultraviolet transmission, and a low total solar energy transmission. According to the present invention, an ultraviolet and infrared radiation absorbing glass having enhanced infrared radiation absorbing power while retaining a high visible light transmission can be obtained by regulating the total iron oxide content to a value as small as from 0.20 to 0.30% and regulating the proportion of FeO in terms of Fe 2 0 3 to a relatively large value of from 20.5 to 25% based on the total iron oxide. Furthermore, the glass has been regulated so as to have a Ce0 2 content of from 0.65 to 1.1% for facilitating reduced melting and have a Ti0 2 content of from 0.35 to 1.1% for compensating for insufficiency of ultraviolet radiation absorbing power. Thus, the glass according to the present invention is an excellent ultraviolet and infrared radiation absorbing glass which combines a bronze or neutral gray tint, obtained by the coloration of Se in combination with that of CoO, a low ultraviolet transmission, and a low total solar energy transmission. According to the preferred embodiment, a glass tinted with a regulated bronze or neutral gray tone while retaining the various optical characteristics attained due to the above constitution can be obtained by incorporating NiO. According to the further preferred embodiment, a glass having improved chemical durability and a reduced ultraviolet transmission while retaining the various optical characteristics attained due to the above constitution can be obtained by incorporating La 2 0 3 . POSSIBLE COMMERCIAL USE OF THE INVENTION As described above in detail, the ultraviolet and infrared radiation absorbing glass of the present invention makes it possible to produce a glass tinted with a bronze or neutral gray tone and having excellent ultraviolet radiation absorbing power. Furthermore, since the ultraviolet and infrared radiation absorbing glass of the present invention has high ultraviolet radiation absorbing power and a bronze or neutral gray tint, it is suitable for use as, e.g., a window glass for automobiles and other vehicles and for buildings. In such applications, the glass of the present invention is highly effective in, e.g., preventing the interior materials from deteriorating or fading.

Claims: CLAIMS 1. An ultraviolet and infrared radiation absorbing glass comprising, in % by weight: basic glass components comprising 65 to 80% Si0 2 , 0 to 5% B 2 0 3 , 0 to 5% A1 2 0 3 , 0 to 10% MgO, 5 to 15% CaO, 10 to 18% Na 2 0, and 0 to 5% K 2 0, provided that the sum of MgO and CaO is 5 to 15% and the sum of Na 2 0 and K 2 0 is 10 to 20%; coloring components comprising 0.20 to 0.30% total iron oxide (T-Fe 2 0 3 ) in terms of Fe 2 0 3 0.65 to 1.1% Ce0 2 , 0.35 to 1.1% Ti0 2 , 0.001 to 0.005% CoO, and 0.0003 to 0.0015% Se; and an additional component comprising 0.02 to 0.30% S0 3 , wherein 20.5 to 25% of said T-Fe 2 0 3 is FeO in terms of Fe 2 0 3 . 2. The ultraviolet and infrared radiation absorbing glass of claim 1, which further comprises 0.0005 to 0.005% by weight NiO. 3. The ultraviolet and infrared radiation absorbing glass of claim 1 or 2, which further comprises 0.20 to 0.90% by weight La 2 0 3 . 4. The ultraviolet and infrared radiation absorbing glass of any one of claims 1 to 3, which has a visible light transmission of 70% or more as measured with the CIE standard illuminant A, when the glass has a thickness of 3.25 to 6.25 mm. 5. The ultraviolet and infrared radiation absorbing glass of any one of claims 1 to 4, which has a solar energy transmission of less than 72%, when the glass has a thickness of 3.25 to 6.25 mm. 6. The ultraviolet and infrared radiation absorbing glass of any one of claims 1 to 5, which has a dominant wavelength and an excitation purity as measured with the CIE standard illuminant C of 572 to 580 nm and 8% or less, respectively, when the glass has a thickness of 3.25 to 6.25 mm. 7. The ultraviolet and infrared radiation absorbing glass of any one of claims 1 to 6, which has an ultraviolet transmission defined in ISO 9050 of less than 12%, when the glass has a thickness of 3.25 to 6.25 mm.

Inventors: NAKAGAKI SHIGEKI, SAKAGUCHI KOICHI, NAKAGAKI, SHIGEKI, SAKAGUCHI, KOICHI
Applicants: NAKAGAKI SHIGEKI, NIPPON SHEET GLASS CO LTD, SAKAGUCHI KOICHI, NAKAGAKI, SHIGEKI, NIPPON SHEET GLASS COMPANY, LIMITED, SAKAGUCHI, KOICHI
Application year: 1998
Main classification: C03C3
IPC codes: C03C1, C03C3, C03C4