JPS5879848A - Laminated glass - Google Patents

Abstract

PURPOSE:To manufacture a laminated glass having excellent strength and transparency, by interposing a composition obtained by compounding an ethylene- vinyl acetate copolymer with a plasticizer and a peroxide or a photosensitizer between a pair of glass plates, and curing the composition by heating at or above the melting point of the resin. CONSTITUTION:A film or sheet of a composition composed of (A) an ethylene- vinyl acetate copolymer (EVA) having a VA-content of about 10-40wt% and a melt flow index of about <=15, (B) about 0.5-30pts., based on 100pts. of the composition, of a plasticizer such as high purity paraffin oil, etc., and (C) about <=5pts., based on 100pts. of EVA, of a peroxide or a photosensitizer, is interposed between a pair of glass plates, and made uniform by squeezing out the voids, etc. The integrated glass is heated above the melting point of the crystals in EVA, and the composition is crosslinked with ultraviolet-visible light irradiation or by heating to obtain a laminated glass having excellent transparency and impact strength.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminated glass used for automobile windshields, building glass, etc., and more specifically, it has sufficient practical strength as an interlayer film, excellent processing workability, and transparency. This invention relates to laminated glass made of materials with excellent properties.

Conventionally, the interlayer film of laminated glass is polyvinyl butyral film (
Although PVB (hereinafter abbreviated as PVB) is widely available, the films tend to viscous each other and cause so-called blocking. To avoid this, a powder such as sodium bicarbonate is generally sprinkled on top of the embossed surface during membrane processing.

Before use, it must be washed with water and dried.

In order to obtain an appropriate adhesion force, complicated steps such as adjusting the moisture content of the film are taken. In addition, the fact that heating and pressure is required in an autoclave in the final adhesion process with glass is undesirable from the perspective of process automation, etc. The present inventors have already developed ethylene-vinyl acetate as a new laminated glass material that has improved these drawbacks. By crosslinking a copolymer (hereinafter abbreviated as FiVA) while maintaining it above its crystal melting point, it has excellent transparency, sufficient practical strength, and has little blocking property during processing.
Furthermore, it was disclosed that continuous processing steps can be used (
Patent application Sho 5S-80915). However, this composition still contains crosslinking agents such as fugitives.

There are restrictions on the adding temperature or the processing temperature when forming the composition into a film, and especially when using materials with a low melting index or materials containing vinyl acetate (hereinafter abbreviated as VA amount),
For materials with a thickness of less than 0.0 cm, it is difficult to form a uniform film unless the processing temperature is increased, and the pressure bonding temperature when clamping the film to glass also tends to be high. For example, when a composition is formed into a film by an extrusion method, an inflation method, a calendar method, a press method, etc., such an increase in processing temperature tends to cause scorch inside and outside the processing machine.
Particularly in processing machines, this not only results in material loss, but also requires disassembly and cleaning of the processing machine, resulting in huge losses in terms of both productivity and costs.

The present inventors took these points into consideration and as a result of intensive research, they found that adding a certain amount of plasticizer to the composition lowers the processing temperature, avoiding the above problems and at the same time reducing the The present invention was completed based on the discovery of the previously unknown fact that it is useful for improving transparency as a glass material and does not substantially impair impact resistance. That is, the present invention interposes between glass plates a heat- or photo-curable resin composition prepared by blending an ethylene-vinyl acetate copolymer with a plasticizer and peroxide or a plasticizer and a photosensitizer. It is a laminated glass made by integrating the resin layer and curing the resin layer by heating at a temperature higher than the melting point of the resin or by irradiating light.

Ethylene-vinyl acetate copolymer (K
The VA amount of VA) is preferably 10 to 40% by weight, and the melt flow index is preferably 15 or less. VA amount is 1
If the VA content is less than 0%, it is unsuitable as a laminated glass material for transparent applications due to its high value, and if the VA content is more than 40%, the effect of the present invention is small. Similarly, the effect of the present invention is small for EVA with a melt flow index of 15 or more.

As previously disclosed, the EVA of the present invention contains appropriate amounts of a crosslinking agent such as peroxide and a photosensitizer, but to achieve the present invention, it further contains 0.5 to 30 parts of a plasticizer, preferably 1 part. ~10
part is added to the above composition. The amount of plasticizer that can be added is E
It is determined by taking into consideration the compatibility with VA, the required transparency, the impact resistance after being combined with glass, etc., but if it is less than 0.5 parts, there will be little substantial effect, and if it is more than 50 parts, it will affect the composition. Bleeding of the plasticizer or deterioration of physical properties is extremely undesirable.

Plasticizers that can be used for the purpose of the present invention include high-purity paraffinic and naphthenic oils, phthalate esters, adipate esters, separatate esters, thioglycols, and Ether plasticizers such as benzyl ether, phosphoric acid plasticizers such as tricresyl phosphate, maleic acid esters such as dioctyl maleate, ether plasticizers, and the like are used.

These plasticizers may be mixed with EVA using a processing machine such as an extruder, roll mill, Banbury, etc.
VA may be immersed in these plasticizers at room temperature or under heating to cause swelling, and a blender, ball mill, etc. may also be used to promote this swelling. Also, the plasticizer is IBVA
It may be added simultaneously with the peroxide or photosensitizer or prior to the addition of the peroxide or photosensitizer. Addition of such a plasticizer is necessary when uniformly mixing peroxide and photosensitizer into KVA, and when forming a film or sheet using various processing machines. By lowering the temperature, it is possible to prevent gelation, scorch, etc. of the composition.

The amount of peroxide or photosensitizer to be blended is 5 parts or less per 100 parts of EVA. Furthermore, other additives such as anti-aging agents, ultraviolet absorbers, cross-coupling agents, coloring agents, etc. can be added as appropriate depending on the purpose.

The composition of the present invention in the form of a film or sheet obtained as described above is sandwiched between two glass plates while being heated, and the air bubbles etc. existing between the glass plate and the sheet are expelled and the composition is homogenized. be done. A second advantage of the present invention is that the heating temperature during this sandwiching and leveling can be lowered. As for the method of sandwiching and integrating, the rubber bag method, nip roll method, etc. are adopted as in the case of conventional PVB films. Integrated laminated glass continues to be an EV
It is heated above the melting point of the crystals in A, and is stirred by ultraviolet to visible light or heating, and has excellent 'rh brightness and impact resistance, and is an excellent material that prevents glass from scattering, falling, peeling, etc. when broken. It becomes glass. Which of the above methods is used for crosslinking depends on the formulation of the composition. Needless to say, the transparency of laminated glass is an extremely unique performance, but the present invention has been found to be able to further improve this point, especially when the VA amount is about 20 inches, which was an effect that could not have been predicted in the past. Furthermore, although the addition of plasticizers generally tends to cause deterioration of physical properties, the present invention has also obtained unexpectedly favorable results in that it does not affect the impact resistance of laminated glass.

Next, the present invention will be explained with reference to Examples.

Example I The composition shown in the table below was kneaded in a roll mill to obtain a uniform composition.The roll temperature was set to a small extruder with a screw diameter of 40mm and a T-die (slit 05-1 width 400m, mouth temperature 1).
00℃) to determine the low-temperature extrudability of the compound, and the temperature at which the sheet can be inserted between two glass plates and inserted into a rubber bag, and the sheet and glass plate can be uniformly integrated under reduced pressure (visual observation). was evaluated.

■Melt flow index value (J engineering 5K6-730)
As is clear from the table, all plasticizer formulations lower the crosstalk temperature of the composition and the sandwiching and integration temperature with glass,
Furthermore, film formation was possible at a temperature of 100° C. or lower.

Example 1 The compositions shown in the table below were kneaded in a roll mill and then pressed to form a sheet of 0.4 ws thickness x 300 mm x 300+w. Put this sheet into two 3 sheets x 500 x
It was placed between 301] m of float glass, further inserted into a rubber bag, and degassed at 75° C. under reduced pressure to produce a uniform laminated glass without bubbles. This laminated glass is heated on a heat press for 16
The mixture was heated at 0° C. for 20 minutes to effect crosslinking, thereby obtaining a transparent balanced glass. The haze value (haze value) of the laminated glass was measured using an integral turbidity meter TC-BP manufactured by Tokyo Denshoku Co., Ltd.

As is clear from the table, a reduction in haze value (improvement in M1 brightness) is observed in all plasticizer formulations.

Example・■ The formulations in the table below were mixed and processed in the same manner as in Example 1, and 300WX3001 with a float glass thickness of 3mm and an intermediate film thickness of 045mm was prepared.
A 1m+ laminated glass was created. This laminated glass is based on J-K83211 and 3212, and the weight is 2.3 K9.
A steel ball with a smooth surface was dropped from a height of 1.5 m to evaluate its impact resistance.

As can be seen from the table, the formulations of the Examples result in virtually no reduction in impact resistance.

Patent applicant Brideston Tire Co., Ltd. Patent attorney Akira Ito Procedural amendment dated January 17, 1980 Commissioner of the Japan Patent Office Shima 1) Haruki Tono1, Indication of case Patent application No. 176549, 1982, Invention Name of Laminated Glass 5, Relationship to the case of the person making the amendment Patent applicant Address 1-10-1 Kyobashi, 1-1, Chuo-ku, Tokyo Name Bridestone Tire Co., Ltd. Representative Kuni Hattori
Male 4, agent〒,. 1 Address: Sen, Tokyo (2-42-5, Kanda Jimbocho, J-ku, subject to amendment)

Claims (1)

[Claims] A heat or photo-curable resin composition prepared by blending an ethylene-vinyl acetate copolymer with a plasticizer and peroxide or a plasticizer and a photosensitizer is interposed between glass plates and integrated with the glass plates. Laminated glass made by hardening the resin layer by heating or irradiating it with light at a temperature above the melting point of the resin.