JPH0260621B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention improves the adhesion properties of the films to each other and has good bleed resistance, and when laminated glass is manufactured by laminating glasses, the laminated glass has improved impact resistance and The present invention relates to a laminated glass with good stability in the periphery. It is widely known that a film made of plasticized polyvinyl butyral, which is obtained by adding a plasticizer to polyvinyl butyral, is used as an interlayer film for bonding laminated glass. The plasticized polyvinyl butyral film has excellent adhesive strength, light stability, transparency, and low-temperature flexibility, and is widely used today as an interlayer film for laminated glass for automobiles, aircraft, and architecture. However, in conventional interlayer films for laminated glass, the adhesiveness of the film surface is strong, so the films stick to each other during winding after film formation (hereinafter referred to as self-adhesion of the interlayer film).
In order to prevent such adhesion, anti-adhesion agents such as bicarbonate of soda are sprayed on the membrane surface.
Cooling of the interlayer film to a temperature of 20° C. or lower has been carried out. However, the method of spraying an anti-adhesive agent has the disadvantage that it requires a washing process and a drying process to remove the anti-adhesive agent before bonding the polyvinyl butyral film and glass. However, refrigeration equipment is required for the production, packaging, transportation, storage, and use of the interlayer film, which is expensive. In view of the above-mentioned current situation, the present invention provides a laminated glass that has improved self-adhesiveness and that, when manufactured by laminating glasses, can produce a laminated glass that has improved impact resistance and peripheral stability. The purpose of this study was to provide an interlayer film for industrial use, and its gist is to calculate the degree of butyralization as X (mol%), the vertical axis as the transmittance, and the horizontal axis as the wave number. When the half width is Y (cm ^-1 ), (1)
The general formula for polyvinyl butyral satisfying the formula Y≧−3X＋486 (1) (In the formula, R' ₁ and R' ₂ are each an alkyl group having 1 to 8 carbon atoms, m ₁ and m ₂ are each an integer of 2 to 4, and n is 1 to 10
indicates an integer. ) is added, and the T-peel strength between the films at 20℃ increases.
An interlayer film for laminated glass characterized by a weight of 0.5 kg/cm or less. In the present invention, the half width is defined as follows. First, in the infrared absorption spectrum of polyvinyl butyral, where the vertical axis is the transmittance (%) and the horizontal axis is the wave number (cm ^-1 ), as shown in Figure 1, there is no infrared absorption at wave numbers 3900 cm ^-1 and 2300 cm ^-1. Connect the positions showing the transmittance at each other and use this as a reference line. Next, the distance from the horizontal axis (transmittance 0%) to the reference line passing through the peak P of the absorption spectrum of the hydroxyl group between wave numbers 3900 cm ^-1 and 2300 cm ^-1 is defined as I _{0, and the peak P of the absorption spectrum of the hydroxyl group is defined as I 0} . Assuming that the distance to I ₁ is I 1 , the transmittance that gives the half-width, that is, the distance I _A from the horizontal axis, is determined as the geometric mean of I ₀ and I ₁ , that is, I _A =√ ₀ × ₁ . Next, consider a point Q whose distance from the vertical axis is that of the peak P of the hydroxyl group spectrum and whose distance from the horizontal axis is _IA . The line segment Y obtained by passing through Q and drawn parallel to the horizontal axis as shown in FIG. 1 intersects the spectrum of the hydroxyl group is the half width (cm ^-1 ). The present inventors have discovered that even if polyvinyl butyral has the same degree of butyralization, the absorption band of the hydroxyl group in its infrared absorption spectrum differs slightly. That is, the half width of polyvinyl butyral that provides an interlayer film with improved self-adhesion is always larger than that of polyvinyl butyral that provides an interlayer film with high self-adhesion even if the degree of butyralization is the same. The reason for this is still not fully clear, but
Polyvinyl butyral, in which hydroxyl groups are arranged in a chain, tends to have stronger association through hydrogen bonds than polyvinyl butyral, in which hydroxyl groups are arranged irregularly, and it is believed that this increases rigidity and, therefore, provides an interlayer film with less self-adhesion. The hydroxyl group absorption band in the infrared absorption spectrum of polyvinyl butyral is on the lower energy side, that is, on the lower wave number side, because there is a part where the association by hydrogen bonds is stronger than that of polyvinyl butyral, where the arrangement of hydroxyl groups is irregular. It is thought that the half width of hydroxyl group absorption increases due to swelling. This is probably because the interlayer film with improved self-adhesion provided by the present invention has both appropriate rigidity and appropriate adhesion to glass, making it possible to manufacture laminated glass with excellent impact resistance. It is something to do. The degree of butyralization of the polyvinyl butyral used in the present invention is 60 to 75 mol% because if it is too low, it will have poor compatibility with plasticizers, and if it is too high, various physical properties such as penetration resistance will decrease when laminated glass is made. It is desirable that there be. For measuring the degree of butyralization, known methods such as the hydroxylamine hydrochloride method are appropriately employed. Polyvinyl butyral satisfying the above formula (1) can be obtained by, for example, a precipitation method, by adding butyraldehyde to an aqueous polyvinyl alcohol solution in the presence of an acid catalyst to obtain a precipitate at a relatively low temperature, and then heating the reaction system. It can also be obtained by aging at high temperature for a long time, followed by neutralization, washing with water, and drying using conventional methods.
In that an interlayer film with improved self-adhesion can be obtained,
A method in which polyvinyl butyral is aged in the presence of a perchloric acid compound is preferred. Specifically, a perchloric acid compound is added to an aqueous polyvinyl alcohol solution into which a catalyst such as hydrochloric acid is added dropwise, and then butyraldehyde is added to precipitate the solution at a temperature of 20° C. or lower. In addition to perchloric acid, perchloric acid compounds include alkali metal salts of perchloric acid such as sodium perchlorate and potassium perchlorate, and alkaline earth metal salts such as magnesium perchlorate and calcium perchlorate. Among them, sodium perchlorate is particularly preferred, and these are usually added in an amount of 0.2% by weight or more based on the final reaction system. Thereafter, the temperature of the reaction system is raised and maintained at a temperature of 30 DEG C. or higher, usually for 1 to 15 hours, to ripen the polyvinyl butyral, and a dry powder is obtained according to a conventional method. The perchloric acid compound may be added to the reaction system simultaneously with the start of ripening. When producing the polyvinyl butyral used in the present invention, it is preferable that the average degree of polymerization of the raw material polyvinyl alcohol is 800 to 3000, and the degree of saponification is 95 mol% or more in order to obtain polyvinyl butyral with good transparency. is preferred. For polyvinyl butyral that satisfies the above formula (1), plasticizers such as triethylene glycol di2-ethyl butyrate and triethylene glycol di2-ethylhexoate, which are commonly used in conventional polyvinyl butyral, are used. However, when the laminated glass obtained from this interlayer film is used for a long period of time, the adhesion at the periphery of the glass tends to decrease (plasticizer (This is presumed to be due to bleeding of the film), and in severe cases, the film and glass may separate or bubbles may occur. Therefore, in the present invention (In the formula, R' ₁ and R' ₂ are each an alkyl group having 1 to 8 carbon atoms, m ₁ and m ₂ are each an integer of 2 to 4, and n is 1 to 10
indicates an integer. ) is used.
The plasticizer represented by the above general formula can be obtained, for example, by esterifying a dicarboxylic acid with an alcohol having at least two ether bonds in the molecule. Specifically, preferred examples of the dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, corkic acid, azelaic acid, and sebacic acid. Among the above alcohols, preferred examples having at least two ether bonds in the molecule include diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, and triethylene glycol monomethyl ether. Examples include glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, and the like. Table 1 shows the formula of a typical plasticizer represented by the above general formula (2) used in the present invention. In the present invention, the plasticizers represented by the above general formula (2) are used alone or in appropriate combinations, and the amount of plasticizer added is preferably 30 to 60 parts by weight per 100 parts by weight of polyvinyl butyral. If the plasticizer content is less than 30 parts by weight, the penetration resistance of the laminated glass will decrease, and if the plasticizer content exceeds 60 parts by weight, a so-called bleed phenomenon will occur in which the plasticizer seeps onto the film surface, and when used as an interlayer film for laminated glass. This is because it has an adverse effect on the transparency and adhesiveness of the film. Additives such as nonionic surfactants, organic carboxylic acids, and metal salts of organic carboxylic acids can be added to the plasticizer used in the present invention to further increase impact resistance. Other appropriate additives such as stabilizers, antioxidants, and ultraviolet absorbers to increase weather resistance and heat resistance are usually supplied to an extruder together with the polyvinyl butyral and the plasticizer, and the interlayer film is formed by extrusion molding. It is said that In the present invention, the T-peel strength between interlayer films at 20°C refers to a value measured as follows in accordance with 7 operations of JIS K 6854 Peel Adhesive Strength Test Method. That is, cut the interlayer film to be measured into a rectangular shape (usually 3 cm x 10 cm), stack the two sheets together, apply an appropriate load (usually 4 to 6 kg), and leave them in a desiccator at 20°C. Adjust the temperature to . and use it as a sample. One end of this sample was peeled off from each other,
After bending the peeled film in a 90° direction to make the whole into a T-shape, grab both ends of the peeled film with a tensile tester and measure the peel strength at 20℃ and a tensile speed of 500mm/min. . The interlayer film of the present invention has a T-peel strength between the films at 20°C measured by the above-mentioned measuring method of 0.5 Kg/cm or less, and usually 0.2 Kg/cm or more. The interlayer film of the present invention is constructed as described above, and a plasticizer represented by the general formula (2) is added to polyvinyl butyral satisfying the above formula (1), so that T-shaped peeling between the films at 20°C is achieved. Strength is 0.5
Kg/cm or less, the films do not stick to each other during winding after film formation, so there is no need to spray an anti-stick agent on the surface of the interlayer film or freeze the interlayer film. In addition, the impact strength of the laminated glass produced using the interlayer film of the present invention is of a level that can be put to practical use over a wide range, and the impact resistance in low temperature regions in particular is greatly improved. Furthermore, the interlayer film of the present invention has good bleed resistance, and a laminated glass with good peripheral stability over a long period of time can be obtained. Examples of the present invention are shown below. Parts and % simply indicate parts by weight and % by weight. In addition, each physical property value in Examples was based on the following measuring method. 1 Impact resistance Adding and kneading a plasticizer to polyvinyl butyral,
Plasticized polyvinyl butyral with a thickness of 0.76 mm was obtained using an extruder. This film has a thickness of 3.0mm and 30
Sandwiched between two glass plates measuring cm x 30 cm, the temperature
A laminated glass was obtained by heating and pressing for 15 minutes at 120° C. and a pressure of 12 Kg/cm ² . After storing this laminated glass at the specified temperature for more than 8 hours, place it horizontally on a square iron frame with an outer frame of 31 cm x 31 cm, an inner frame of 26 cm x 26 cm, and a height of 20 cm. A ball was dropped from a specified height onto the center of the laminated glass. The height at which 50% of the steel balls penetrate the laminated glass is defined as the penetration resistance. In addition, as a sample of laminated glass, by using a plasticizer in which an appropriate amount of the same metal soap was added and mixed in advance, the pummel value described below was set to 6, which is the range normally used as a product. 2. Adhesion to glass The laminated glass was adjusted by leaving it at a temperature of -18°C ± 0.6°C for 16 hours, and was crushed by hitting it with a hammer with a head weighing 0.45 kg until the particle size of the glass became 6 mm or less. The degree of exposure of the film after the glass was peeled off was determined using limit samples that had been graded in advance, and the results were expressed as pummel values according to Table 2.

[Table] 3 Self-adhesion The interlayer film used for impact resistance measurement was heated at 150℃ for 40 minutes.
A uniform film with a smooth surface and a thickness of 0.76 mm was prepared by hydraulic pressing at Kg/cm ² for 3 minutes. This film was cut into a rectangular shape of 3 cm x 10 cm, two sheets were stacked together, and the film was placed in a desiccator kept at a temperature of 20° C. for 48 hours under a load of 6 kg. One end of the sample obtained in this way was peeled off from each other,
After bending the peeled piece in the 90° direction and making it into a T-shape,
Both ends of the peeled film were held in a tensile tester and the T-peel strength was measured at 20° C. and at a tensile speed of 500 mm/min. 4 Compatibility 8g polyvinyl butyral for 100g plasticizer
was added and heated to 170°C in an oil bath to dissolve the contents, and then cooled at a rate of 2°C/min, and the temperature at which clouding occurred was defined as the cloud point. The lower the cloud point, the better the compatibility between the plasticizer and polyvinyl butyral. 5 Bleed Resistance Interlayer films were cut into 5 cm x 5 cm samples and stored at 22° C. in 100% relative humidity for 5 days and visually tested for plasticizer leaching. A case where there was no visible exudation was considered good. 6 Peripheral Stability Test A 30 cm x 30 cm laminated glass obtained from a glass with a thickness of 3 m/m and an interlayer film with a thickness of 0.76 mm was exposed at an angle of 45° to the horizontal plane in Minakuchi-cho, Shiga Prefecture. (A) Pummel value was measured after 3 months. Comparing the adhesion between the central part of the sample and the part within 10 mm from the periphery, if the pummel value of the peripheral part is lower than that of the central part by more than 4, Δ, 3
Those whose pummel value decreased by ~4 were designated as ○, and those whose pummel value decreased by less than 3 were designated as ◎. (B) After one year of exposure, the external appearance of the surrounding area was observed. A case where no foaming, peeling, or other abnormality occurred in the peripheral area was considered good. 7 Measurement of half width of hydroxyl group 1 g of polyvinyl butyral was mixed with 10 c.c. of butanol,
It was dissolved in a mixed solvent of 15 c.c. of ethanol, cast on a mirror surface, and then dried in a vacuum drier at 60°C for 3 hours to obtain a polyvinyl butyral film. The infrared absorption spectrum of this film was measured using Hitachi's EPI
-G ₃ It was measured using a diffraction grating infrared spectrophotometer, and the half-width of the hydroxyl group was determined based on FIG. 1 in accordance with the definition of half-width in the present invention. Example 1 After completely dissolving 100 kg of polyvinyl alcohol with a degree of saponification of 99.2 mol% and a degree of polymerization of 2200 in 880 kg of distilled water, 57 kg of concentrated hydrochloric acid and 25 kg of 60% sodium perchlorate were added and kept at 14.4°C, and 51.9 kg of butyraldehyde was dissolved. was added dropwise for 15 minutes, and 10 minutes after the dropwise addition, a polyvinyl butyral precipitate was obtained. This reaction system was heated to 40
After being kept at the thermoforming temperature of °C for 10 hours, the temperature was lowered and neutralized with baking soda. The obtained polyvinyl butyral was washed with water and dried, and the degree of butyralization was determined to be 62.5 mol%. The infrared absorption spectrum of the obtained polyvinyl butyral was measured and the half width of the hydroxyl group was found to be 322 cm ^-1 . The value of −3X+486 was 298.5, which satisfied equation (1) above. Examples 2 to 4 A polyvinyl alcohol aqueous solution containing a hydrochloric acid catalyst and 25 kg of 60% sodium perchlorate was kept at 14.4°C and butyraldehyde was added to precipitate the reaction system, and then the reaction system was heated and kept at high temperature for a long time. was neutralized, washed with water, and dried according to a conventional method to obtain a white powder of polyvinyl butyral. The various conditions for producing polyvinyl butyral, the degree of butyralization of the obtained polyvinyl butyral, and the half-width of hydroxyl group absorption are shown in Table 3 together with Example 1. Comparative Examples 1 to 4 Polyvinyl alcohol aqueous solution containing hydrochloric acid catalyst
After keeping the temperature at 14.4℃ and adding butyraldehyde to precipitate, the reaction system was heated to 30 to 40℃ for 4 to 8 hours.
The mixture was kept for a certain period of time, and then neutralized, washed with water, and dried according to a conventional method to obtain a white powder of polyvinyl butyral. Table 3 shows various conditions for producing polyvinyl butyral, the degree of butyralization of the obtained polyvinyl butyral, and the half-width of hydroxyl group absorption.

【table】

[Table] * Time maintained at aging temperature ** The polyvinyl butyral obtained in Examples 1, 2, 3, and 4 are referred to as resins A, B, C, and D in this order, and the same applies to comparative examples as well, respectively. , b, c,
It's called d.
Examples 1-1 to 1-2, 2-1 to 2-2, 3-1
~3-3, 4-1 Resins A, B, C, obtained in each example
The self-adhesion of an interlayer film obtained by adding 40 parts of a specified plasticizer to 100 parts of D and the impact resistance of a laminated glass obtained from this interlayer film were measured and shown in Table 4. Table 5 shows the compatibility with the laminated glass, the bleed resistance, and the stability of the peripheral area of the laminated glass.

[Table] A preset sample of sea urchin was used.

【table】

[Table] Comparative Examples 1-1 to 1-4, 2-1 to 2-4, 3-1
~3-6, 4-1 ~ 4-2 Resins a, b, c, obtained in Comparative Examples 1 to 4,
The self-adhesiveness of the interlayer film obtained by adding 40 parts of a prescribed plasticizer to 100 parts of each of d and the impact resistance of the laminated glass obtained from this interlayer film were measured and shown in Table 6. In addition, resins A, B, and B obtained in Examples 1 to 4
Table 7 shows the compatibility between the interlayer film obtained by adding 40 parts of a specified plasticizer to 100 parts of C and D, the compatibility with the plasticizer, the bleed resistance, and the stability of the peripheral area of the laminated glass.

【table】

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a chart showing an example of the infrared absorption spectrum of polyvinyl butyral used in the interlayer film for laminated glass of the present invention. Y...Half width of absorption spectrum of hydroxyl group, P...
...The peak of the absorption spectrum of hydroxyl group.

Claims (1)

[Scope of Claims] 1 When the degree of butyralization is expressed as X (mol %), and the half-width of hydroxyl group absorption in an infrared absorption spectrum where the vertical axis is the transmittance and the horizontal axis is the wave number is Y (cm ^-1 ). , (1) The general formula for polyvinyl butyral satisfying the formula Y≧−3X＋486 (1) (In the formula, R' ₁ and R' ₂ are each an alkyl group having 1 to 8 carbon atoms, m ₁ and m ₂ are each an integer of 2 to 4, and n is 1 to 10
indicates an integer. ) is added, and the T-peel strength between the films at 20℃ increases.
An interlayer film for laminated glass characterized by a weight of 0.5Kg/cm or less. 2. The interlayer film according to item 1, wherein the degree of butyralization is 60 mol% to 75 mol%. 3 The amount of plasticizer added is polyvinyl butyral 100
The interlayer film according to item 1 or 2, which is 30 to 60 parts by weight.