JPH03218940A - Ultraviolet transmitting glass - Google Patents

Abstract

PURPOSE:To provide the UV transmitting glass having a transmittance for UV close to that for the sunlight and with the initial spectroscopic characteristic unchanged by UV irradiation by incorporating specified amts. of Fe2O3, TiO2 and Sb2O3 into a borosilicate glass. CONSTITUTION:From 5 to 80ppm Fe2O3, 50-1000ppm TiO2 and 0.02-1% Sb2O3 are incorporated into a borosilicate glass contg., by weight, 65-80% SiO2, 1-10% Al2O3, 4-12% Li2O+Na2O+K2O, 8-20% B2O3 and 0-10% CaO+MgO+BaO+ZnO. The contents of Fe2O3 and TiO2 are limited to conform to inequalities I and II, and an UV transmitting glass having <=1% transmittance at 255nm wavelength with the glass 2.4mm in thickness and <=68% transmittance at 302nm wavelength is produced. The UV transmitting glass is most appropriately used as a filter for a sunshine carbon arc lamp-type weatherability testing machine.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to ultraviolet-transmitting glass with excellent weather resistance, particularly as a filter used in a sunshine carbon arc lamp type weather resistance tester. Concerning optimal ultraviolet transmission glass.

(Prior Art) A Sunshine carbon arc lamp type weather resistance tester is known as a device for testing the weather resistance and changes in characteristics over time of various industrial materials and products. This device uses an artificial light source (sunshine carbon arc lamp) with luminous properties similar to sunlight as a light source that corresponds to sunlight, in order to quickly examine changes in test materials over time due to natural effects such as sunlight, wind, and rain. A glass filter is used to reduce the ultraviolet transmittance so that ultraviolet radiation equivalent to the actual sunlight reaching the earth's surface is irradiated. Further, it is generally known that the ultraviolet transmittance of glass is largely dependent on the amount of iron contained in the glass, and glasses with low iron content are used for applications that transmit ultraviolet rays. When producing glass industrially, iron is introduced as an impurity in raw materials such as silica sand, or from raw material storage/transport routes, melting furnace materials, etc.

For this reason, in the method of producing glass by blending and melting raw materials, it is extremely difficult to eliminate iron from entering the glass. It was common for glass to also contain affl iron.

(The fIAl!I! that the invention seeks to solve) Iron in glass usually exists in the form of Fe or F●, but when irradiated with ultraviolet light, the original value of p,2 + changes to Fe.
The amount of Fe in the glass increases and colors the glass, resulting in a significant decrease in spectral transmission from the ultraviolet to the visible range. Sansha above? The filter glass used in this carbon arc lamp type weather resistance tester is subject to strong ultraviolet radiation, so this tendency is strong, and the initial transmittance characteristics cannot be maintained for a long period of time, making it impossible to perform proper weather resistance tests. This causes a problem.

The present invention has been made in consideration of these circumstances, and an object of the present invention is to provide an ultraviolet transmitting glass that has ultraviolet transmitting characteristics similar to those of thick rays and whose initial spectral characteristics do not change due to ultraviolet irradiation.

[Structure of the invention]

(Means and effects for solving the divisional labor problem) The present invention has a weight ratio of Fe, 0. 5-80pp
m+'rto, 50 to 1000 ppm
．． 8b, o, 0. (It is a borosilicate glass containing ~1.0% of B, and its transmittance is 1% or less at a wavelength of 255 nm in a glass with a wall thickness of 2.4 s1, and a wavelength of 30 nm.
2 Fim is 68 whispers or more, and the above F@, O,
, T10, is within a range that satisfies the following formula.

400≦[(F@■0, including i)×10+ (Tr
02 content) ≦1100 and the following describes the reasons for each of the above limitations.

The light from the Sunshine Carbon Arc Lamp has a strong energy distribution in the ultraviolet region compared to the sunlight on the earth's surface, so when conducting weather resistance tests in natural conditions, the light from the Sunshine Carbon Arc Lamp is It is necessary to approximate the distribution, so the energy distribution of the light beam is adjusted mainly by passing through a filter with bi-characteristics in the ultraviolet region. Expressing this in terms of the transmittance of the filter at the registered wavelength, a nine glass plate polished to a wall thickness of 2.4 mm has a transmittance of 1% or less at a wavelength of 255 fiffl, and a transmittance of less than 1% at a wavelength of 3.
68% or more at 02 nm, 350-850 f
It is necessary to have a transmittance of 90 or more in the IIH visible range.

The glass of the present invention contains Fe, 0, and T▲0, which act as ultraviolet absorbers, in order to maintain a high transmittance in the visible range and to adjust the transmittance in the ultraviolet range to the desired level. . When r●, 0, is less than 5 ppm, the desired ultraviolet 1 [yield] cannot be obtained, and when it exceeds 80 ppm, the spectral transmittance in the ultraviolet region is too low. In addition, as mentioned above, iron ions in the glass reduce the ultraviolet transmittance due to the reaction of Fe - + Fe + a, so it is not preferable to focus the transmittance adjustment only on iron ions from the viewpoint of aging. . T r 02 is effective in preventing the transmittance of iron ions from decreasing due to ultraviolet @K, but if it is less than 50 pP-, this effect cannot be obtained, and if it exceeds 1000 ppm, the spectral transmittance in the ultraviolet region will exceed the above value. Not satisfied.

Furthermore, the alignment of Pe20 and T10 needs to satisfy the above two equations. F ez O s is Tie, K
It has an ultraviolet absorption effect that is about 10 times that of M-type. Therefore, for each ^ containing filter, (pa2o, containing magnetic)X
If m of 10+(T10, containing 1) is less than 400, it is 2
The transmittance at 5 5 am greatly deviates from 1%, and if it exceeds 1100, the transmittance at 3 0 2 filn falls below 68, so it needs to be within the above l@ range. When the ratio of F● and T+ in Mayu glass, that is, the value of (Fl!20, content m)/(TiO, content *), exceeds 1.5, Fa” due to the presence of TI io/
＋→F＠” ＋＠The effect of suppressing the reaction becomes weaker, and the effect of preventing glass solarization cannot be obtained.sb
, o, has the effect of preventing glass coloration and is added with the expectation of a clearing effect, but if it is less than 0.02%, it has no effect, and if it exceeds 1%, the transmittance in the ultraviolet region decreases. This is not preferable because it lowers the temperature significantly.

The borosilicate glass constituting the present invention has the above-mentioned FsO
TIO, + 8b, O, pond, overlay percentage 23' Si0265 ~ 80% * Ai2o31 ~ 10% T L
+zO+N Karasu 20+K, 04~1 2%, B208~2
0%, CaO+MgO+BaO+ZnO~
It is desirable to have a composition consisting of 10%. SI0
2 is an essential component that forms the glass mesh sfi,
If it is less than 65%, the chemical durability of the glass will decrease, and if it is less than 80%
If it exceeds 100%, the meltability of the glass will deteriorate significantly. M20
3 is effective in preventing glass devitrification and improving chemical durability, but if it is less than 1%, no such effect is observed, and if 10% is recommended, the meltability deteriorates. Alkali gold lI4flt compounds lower the viscosity of glass and improve its melting properties, but if the total amount is less than 4%, it is difficult to melt and form the glass.)
If it exceeds 12 whispers, the chemical durability will be significantly reduced, and the heat resistance and thermal shock resistance will be impaired due to the large coefficient of thermal expansion. B
, 0, lowers the viscosity during melting without increasing the coefficient of thermal expansion of the glass, but if it is less than 81, it has no effect, and if it exceeds 20, the chemical durability decreases.

CaO H MgO e BaO 1 ZnO is added to improve meltability, but if it exceeds 10%, it causes loss of gas, which is not preferable.

Hayabusa of the above ingredients, Amass I F * as necessary
CJ may be added in a total amount up to 1%. λm z O
s is 4F60+person m 2 0 @ →2F 6 2
It is not desirable to add S,0, since it promotes the solarization of the glass by the reaction of S,0, which causes deterioration of the ultraviolet transmittance. These substances can be added up to 1% since they promote settling and give a high degree of homogeneity to the glass.

(Example) Next, Example K of the present invention will be described.

Table 1 shows the basic glass as a weight percentage of 810,71
%. λJ! 0,5.5%l B,0,1 5%lNax
O2.4%. K, 05.6%, Sb201 0.5%
The following shows the initial transmittance and deterioration rate for nine cases in which KT10 and F@sOs2 were added to this glass and the contents were varied. Here, the initial transmittance is wall thickness 2.4m.
255am, 302m of nine sample glass polished into plate shape of m
The deterioration rate is the value obtained by measuring the transmittance at mK.The same sample glass was set in the filter position of the Sunshine carbon arc lamp type weather resistance tester, and after the Sunshine carbon arc lamp was turned on for 200 hours, the deterioration rate was measured again for 3 0 2
The transmittance at am is measured, and the decrease from the initial transmittance is divided by the initial transmittance standard and expressed as a percentage.

In Table 11K1, samples ▲1 to 8 are examples of the present invention K, and samples ▲9 to 10 are comparative glasses.

Table 1 shows that the glasses of the examples according to the present invention all exhibited better UV resistance deterioration rates than the comparative glasses, and the UV S transmittance deteriorated less due to solarization of the glass. I understand that. Spectral transmission characteristics t of A2 example glass and A90 comparative example glass shown in Table 1
The younger brother is shown in Figures 1 and 2. In younger brother 1 diagram, curve A is A
2. The initial spectral coverage rate curve of the glass, curve A', is the measurement result after 200 hours of use in a Sunshine carbon arc lamp type weather resistance tester. Similarly, in Figure 2, song 1
Initial spectral transmittance of 1BFiA9 glass 1 song 411
B/ is the measurement result after the same conditions as A2 glass. As is clear from Figures 1 and 42, in the comparative glass, the transmittance deterioration is noticeable on the short wavelength side, whereas the example glass has little deterioration in transmittance over the entire range, and the initial spectral transmission characteristics It is possible to maintain this for a long time.

In addition, Table 2 shows an example in which the basic glass assembly is changed.

Each of these glasses was obtained by mixing raw materials to obtain a predetermined oxide composition and melting the glass at 1450° C. for 5 hours in a platinum crucible. In Table 2, the initial transmittance and deterioration rate are the values measured and calculated in the same manner as in Table 1 above. Indicates the value measured by 9.

In Table 2, R and O are Na, 0. K.O. L import 0
R'O is the total amount of MgO. CaO*ZnO
．． It represents a combination of BaO, and the composition is expressed as a weight percentage.

Changes over time in optical time characteristics such as a uniformity of glass are affected not only by the solarization described above but also by surface deterioration due to weathering. As shown in Table 2 K, the glasses of Examples according to the present invention exhibit good water resistance, and from this point of view as well, they are excellent with little change over time.

Due to the above-mentioned excellent properties, the glass of the present invention can be applied not only to filters for sunshine carbon arc lamp type weather resistance testers, but also to various applications requiring ultraviolet transmission properties.
It can maintain stable lining properties for a long period of time even in harsh environments of high temperature and humidity. For example, lighting systems are being considered that increase the visibility of pedestrians and motorcycles at night by using ultraviolet light sources in automobile headlamps, and by utilizing the fluorescent effects of fibers, paints, etc. The glass of the present invention is ideal as a lens material for automobile headlights in terms of ultraviolet permeability, weather resistance, heat resistance, etc.

〔Effect of the invention〕

As described above, the glass of the present invention has excellent chemical durability against solarization caused by extraneous I1jlWA radiation, and therefore can maintain its initial spectral properties over a long period of time. can.

[Brief explanation of drawings]

FIG. 1 is a curve diagram showing the spectral transmission characteristics of the example glass according to the present invention, and FIG. 2 is a curve diagram showing the spectral transmission characteristics of the conventional example glass. A, A'...1... Example glasses of the present invention B, B'...
1. Conventional glass

Claims (2)

[Claims] (1) Weight ratio: Fe_2O_35-80ppm, Ti
O_250-1000ppm, Sb_2O_30.02
A borosilicate glass containing ~1.0%, the transmittance of which is 255 nm in wavelength in a glass with a wall thickness of 2.4 mm.
1% or less at a wavelength of 302 nm, and 68% or more at a wavelength of 302 nm, and the content of Fe_2O_3 and TiO_2 is within a range satisfying the following formula. 400≦[(Fe_2O_3 content)×10+(TiO
_2 content) ≦1100 and (Fe_2O_3 content) ≦1.5 (TiO_2 content) (2) The borosilicate glass according to claim 1 contains, in addition to the above components,
SiO_265-80%, Al_2O_3 in weight percentage
1-10%, Li_2O+Na_2O+K_2O4-1
2%, B_2O_38-20%, CaO+MgO+Ba
The ultraviolet transmitting glass according to claim 1, characterized in that it has a composition consisting of 0 to 10% O+ZnO.