CS261138B1 - Mixture for the production of polyvinyl butyral films intended for laminated safety glass - Google Patents

Abstract

The solution concerns a mixture for the production of polyvinyl butyral films intended for laminated safety glass used in construction or transport. The most commonly used configuration is glass-film-glass, where the film from the mixture according to the invention influences the optical properties of the laminated glass depending on the composition. The effect itself is manifested by a reduction in the level of penetrating radiation in the UV, VIS and IR spectral regions, while there is no negative distortion of the color of objects or sources of colored radiation. The mixture for the production of such a film consists of 55 to 85 parts by weight of polyvinyl butyral, 15 to 45 parts by weight of a plasticizer, the addition of the active ingredient 0.005 to 5 parts by weight of carbon black and possibly other additives such as UV absorbers, antioxidants, pigments and regulators of adhesion of the film to the glass. The carbon black used has an acidic, neutral or alkaline pH value, an average particle size of 10 to 500 μm and a specific surface area of 5 to 450 m2/g.

Description

The solution concerns a mixture for the production of polyvinyl butyral films intended for laminated safety glass used in construction or transport. The most commonly used configuration is glass-film-glass, where the film from the mixture according to the invention influences the optical properties of the laminated glass depending on the composition. The effect itself is manifested by a reduction in the level of penetrating radiation in the UV, VIS and IR regions of the spectrum, while there is no negative distortion of the color of objects or sources of colored radiation. The mixture for the production of such a film consists of 55 to 85 parts by weight of polyvinyl butyral, 15 to 45 parts by weight of a plasticizer, the addition of the active ingredient 0.005 to 5 parts by weight of carbon black and possibly other additives such as UV absorbers, antioxidants, pigments and regulators of adhesion of the film to the glass. The carbon black used has an acidic, neutral or alkaline pH value, an average particle size of 10 to 500 ,«m and a specific surface area of 5 to 450 m ² /g.

The invention relates to a mixture for the production of polyvinyl butyral films intended for laminated safety glass. These films are combined with layers of glass using a special technological process, thus creating a laminate with safety properties. The polyvinyl butyral films themselves do not have any technical properties.

The production of these films is usually carried out by extrusion on single-screw or twin-screw extruders with melt filtration, which is further shaped by a wide-slot extrusion head into the resulting flat shape. A mixture is fed into the extruder, which is formed by mixing the powdered polymer polyvinyl butyral with a plasticizer.

Depending on the desired final properties of the film, a suitable ratio of the amount of polymer and plasticizer is selected, or various additives are added to modify the polyvinyl butyral film.

It is almost a rule that the polymer already contains the necessary amount of heat stabilizer from the manufacturer, which prevents the degradation of the melt during extrusion at temperatures up to 220 ^Q C and later also when the final products are exposed to sunlight or other heat sources. Practically all film manufacturers also add stabilizers against ultraviolet radiation, so-called UV absorbers, to the mixture. Since polyvinyl butyral films are combined into the resulting laminate with layers of glass, it is possible to add substances that increase or decrease the adhesion of the film to the glass, which is very important to optimize in order to achieve the safety character of laminated glass. Another option is of course to adjust the color of the film by adding a certain amount of pigments.

The finished films are used exclusively for the production of laminated safety glass for applications in the construction industry or for glazing vehicles. In both basic applications, the main useful property is the safety character of the laminate, which significantly reduces the possibility of personal injury in the event of breakage or impact with* laminated safety glass*.

'The production of laminated safety glass usually takes place in two stages. In the first stage, the so-called pre-pressing is carried out, during which air must be removed from the interface between the loosely stacked layers of glass and polyvinyl butyral foil. The most common configuration is glass-foil-glass, but it can also be multilayered, or other plastic, most often transparent, layers can be incorporated into the laminate. Pre-pressing can be carried out by expelling air between the individual layers by passing them between two rubber-coated rollers or by vacuuming the air using a sealing rubber peripheral* profile.

The second stage of laminated safety glass production is pressing, which is carried out in pressure vessels — autoclaves. During pressing, the product acquires its final appearance and properties.

Since the laminate consists of different layers, each layer influences the resulting optical properties of the laminate with its optical properties. The most common combination is glass and polyvinyl butyral foil. For example, if we make a laminate from two 3 mm thick glasses by combining them with a 0.8 mm thick polyvinyl butyral foil, we can measure the absorption of UV radiation up to wavelengths of 310 to 315 nm during tests. If we add a suitable type of UV absorber to the foil recipe, a laminate of the same composition can absorb UV radiation up to 360* to 395 nm. Improving the absorption properties of UV radiation is of great importance, for example, in the protection of art objects, but also of various materials and biological solutions, in which the action of ultraviolet radiation could cause undesirable changes.

The second area of the solar radiation spectrum is the visible region, referred to as VIS, which lies in the wavelength range of 400 to 780 nm. Whether a UV absorber is used for the production of the film or not, we achieve light transmittance values of almost 90% in the glass-film-glass laminate. This can be disadvantageous, for example, when applying the laminate for glazing museums or galleries, because a constant level of lighting is required in them, which is therefore usually provided by artificial sources. However, in the case of strong sunlight, the described laminate transmits almost all the radiation inside and disrupts the constancy of the internal lighting.

High permeability of infrared radiation, i.e. radiation with wavelengths above 780 nm in the IR spectrum, has an adverse effect on the temperature in the room. In the case of using laminate for glazing vehicles, solar radiation is not only a source of heat, but also dazzles the driver, which is also undesirable.

There is an attempt to eliminate these disadvantages by coloring the laminate, either using colored glass or colored polyvinyl butyral foil. Such a laminate suppresses the value of penetrating radiation in the UV, VIS and IR regions of the spectrum and mitigates the negative effects of intense sunlight described above.

But even this solution has a certain drawback in that the course of the radiation transmittance curve in the visible region of the spectrum does not guarantee the elimination of the possibility of color distortion of the perception of an object or light source of a certain color that is observed through such a laminate (or exhibits observed in a room glazed with this laminate.

This disadvantage is eliminated by the mixture for the production of polyvinyl butyral film according to the invention. It is a mixture in which, in addition to the usual additives, there is a UV absorber and a certain concentration of carbon black. A laminate made from a film of this composition does not cause distortion of the color perception, which is the result of the fact that the course of the radiation transmittance curve in the VIS region of the spectrum is uniform. Carbon black has the ability to evenly attenuate radiation of all wavelengths in the visible region of the spectrum. It can be used with carbon blacks of suitable color and resulting effect to achieve the appearance and functional properties of the laminate.

According to the most characteristic properties, it is possible to use acidic, neutral and basic carbon blacks, carbon blacks with an average particle size of 10 to 500 μm and with a specific particle surface area measured by the BET method of 5 to 450 ^m2 /g. Of course, the type and concentration of carbon black and UV absorber can influence the level of radiation transmittance in all three spectral regions. The course of the radiation transmittance curve in the VIS region is then parallel or almost parallel to the wavelength axis and there is no fluctuation in the level of radiation transmittance of more than 10%.

The subject of the invention is a mixture for the production of polyvinyl butyral films containing polyvinyl butyral with a content of hydroxy groups, determined as polyvinyl alcohol, 15 to 30% by weight, a plasticizer and optionally other additives, such as UV absorbers, antioxidants, pigments, and adhesion regulators, which is characterized in that it additionally contains a combination of the above-mentioned properties, with the content of the individual components in the mixture:

polyvinyl butyral 55 to 85 parts by weight (w. d.j, plasticizer 15 to 45 d. h., carbon black 0.005 to 5 -d. -h. and optionally other additives up to 5 d. h.

In the following examples, different types of carbon black with the following specifications were used:

Soot Type ,pH Mean particle size Specific surface DG-100 channel 3.4 to 4.5 17 to 45 μΐη 90 to 100 ^m2 /g -Nigros I retort 7 to 8.5 18 to 28 -um 95 to 135 ^m2 /g TG-10 thermal 7 120 to 190 ft. 12 to 16 ^m2 /g Example 1 cars that prevent glare for the driver

A 0.8 mm thick polyvinyl butyral film with a blue-green stripe was produced using co-extrusion technology. The formulation of the colored part of the film was as follows in parts by weight:

Hydropolyvinylbutyral (18.1 xyl groups) dihexyl adipate

UV absorber of the benztriazole type 0.3 green powder pigment 0.05 blue powder pigment 0.015

This film was to be used for the production of laminated safety glass for the sun. Due to the fact that laminated glass with this film significantly distorts the passing light rays in the visible part of the spectrum, it became impossible to distinguish the red warning light on traffic lights through this laminated glass.

Therefore, it is not possible to use such a film for the production of laminated safety glass in transport.

Example 2

For the production of 0.8 mm thick polyvinyl butyral film with a shading strip, the following recipe was used for the colored part of the film in parts by weight:

Gray-blue stripe

Brown stripe

polyvinyl butyral 75 75 (18.4% hydroxyl groups) -dihexyl adipate 25 25 benztriazole UV absorber 0.3 0.3 s-aze DG-100- 0.035 — soot Nigros I — 0.0175 yellow powder pigment — 0.001 purple powder pigment — 0.0025 blue powder pigment — 0.01-25

Films with both brown and gray-blue shading stripes were used to produce laminated safety glass for passenger cars. The distortion of the transmitted light radiation in the visible range was minimal, so there was no distortion of the colors of traffic lights.

The light transmittance level of the windshields at the darkest point in the VIS region of the spectrum was as follows:

Brown stripe light transmittance (%) 10 15

Gray-blue stripe

Polyvinyl butyral film with shading stripes made in this way can be used for the production of laminated safety glass for vehicles.

Example 3

For the production of a gray polyvinyl butyral film 0.8 mm thick, which, after being pressed between two glasses, was to have almost zero radiation transmittance in the UV region, about 50% transmittance in the VIS region and below 40% transmittance in the IR region, a mixture was used with the following composition in parts by weight:

polyvinyl butyral (18.3% hydroxyl groups) 75 dihexyl adipate 25 carbon black TG-10 0.02

UV absorber of the benztriazole type 0.3 antioxidant substituted phenol 0.2

The film was used for the production of flat laminated safety glass for windows. Laminated glass with this film met the required properties, as it had a transmittance of:

UV range up to 400 nm up to 2% film A polyvinyl butyral 73 (20.4% hydroxyl groups] diethylene glycol di-2-ethyl pelargonate 27 adhesion regulator silicic acid 1 benzotriazole UV absorber 0.3 carbon black TG-10 0.04

VIS range 400 to 780 nm 47 + 3 %

IR range 780 to 2,100 nm up to 36%

The course of the transmittance curve in the VIS region of the spectrum was slightly decreasing, almost parallel to the wavelength axis, so that the laminated glass did not cause distortion of the transmitted light radiation in the VIS region.

This laminated safety glass was used to glaze the gallery windows, and the polyvinyl butyral film used allowed the protection of art objects from ultraviolet radiation and the reduction of daylight intensity to half the level without distorting the color perception, which, together with artificial lighting, created almost constant lighting conditions regardless of sunlight, time of day and weather. At the same time, there was a reduction in the passing thermal radiation, which positively affected the air conditioning conditions.

Attached

The possibilities of regulating the level of radiation transmittance in individual areas of the spectrum are presented by the different compositions of the mixture used for the production of gray polyvinyl butyral films with a thickness of 0.4 mm, in parts by weight:

foil B foil C

73

0.3

0.07

0.3

0.10

Laminated safety glass was produced from films A, B and C, for which various transmittance values were measured:

laminate A

UV range up to 400 nm up to 2%

VIS range 400 to 780 nm 32 + 1 %

IR range 780 to 2,100 nm up to 40%

The courses of the radiation transmittance curves in the VIS region of the spectrum were almost parallel to the wavelength axis. Therefore, laminated glasses with polyvinyl butyral films according to recipes A, B and C did not cause color changes in the VIS region of the spectrum.

Example 1 -a d 5

To produce a greenish-blue polyvinyl butyral laminate B laminate C up to 2% up to 2% up to 19% 8 + 1% up to 29% up to 10% film with a thickness of 0.4 mm, the following mixture was used in parts by weight:

polyvinyl butyral (20.1% hydroxyl groups] 72 diethylene glycol di-2-ethyl pelargonate 27

UV absorber of benztriazole type

0.3

S 11 3 Fj adhesion regulator silicic acid 1 blue powder pigment 0.003 carbon black TG-10 0.04

The film was laminated with flat glass on laminated safety screens placed in front of the windows of buildings. The film between the glasses made it possible to reduce the intensity of incident light radiation by 59%, since its light transmittance in the VIS region of the spectrum is 41%. The course of the transmittance curve in this region does not cause changes in the color of the observed objects. Such laminated glass looks natural and does not distort the view.

Claims (1)

SUBJECT VYNALEZU Mixture for the production of polyvinyl butyral films intended for laminated safety glasses containing polyvinyl butyral with a hydroxyl group content, determined as polyvinyl alcohol, of 15 to 30% by weight, a plasticizer and optionally other additives such as UV absorbers, antioxidants, pigments and adhesion regulators having an acid, neutral or basic pH of a mean particle size of 10 to 500 µm with a specific surface area 5 to 450 m ² / g, with the content of individual components in the mixture: wt. parts polyvinyl butyral softener soot other additives 55 to 85 15 to 45 0.005 to 50 0 to 5