JPH0797240A - Interlayer for laminated glass - Google Patents

Abstract

PURPOSE:To improve the sound insulation and optical strain of the laminated glass by using a laminated film composed of specific two kinds of polyvinyl acetal resin as an interlayer. CONSTITUTION:A polyvinyl alcohol having 500-3000 of average polymerization degree and 78-92% of saponification degree is reacted with a 4-6C aldehyde to obtain a polyvinyl acetal resin having 40mol% or higher of acetalization degree, and 100 pts.wt. of this resin is kneaded with 35-65 pts.wt. of a plasticizer to obtain a resin film (A) having thickness of >=0.05mm. Besides, a polyvinyl alcohol having average polymerization degree of 500-3000 and saponification degree of >=96% is reacted with a 3-4C aldehyde to obtain a polyvinyl acetal resin having >=50mol% of acetalization degree, and 100 pts.wt. of this resin is kneaded with 25-55 pts.wt. of a plasticizer to obtain a resin film (B). It is preferable that the objective interlayer be made up of a sum of two or more layers of the films A and B (esp. B/A/B construction); the interlayer is so constituted as to be 0.3-1.6mm in the overall thickness and also that the thicknesses of A and B are 9-25% and >=0.2mm of a total respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is excellent in sound insulation and
The present invention relates to an interlayer film for laminated glass with little optical distortion.

[0002]

2. Description of the Related Art Generally, a laminated glass having an interlayer film interposed between a pair of glass plates is excellent in safety because fragments are not scattered when it is broken. Widely used for window glass of buildings.

Of these interlayer films for laminated glass,
The polyvinyl butyral resin film plasticized by the addition of a plasticizer has excellent adhesiveness with glass, tough tensile strength, high transparency, etc., and laminated glass made using this film is especially suitable for vehicles. It is suitable as a window glass.

Generally, sound insulation is shown as a transmission loss amount according to a change in frequency, and the transmission loss amount is JIS.
In the A4708, as shown by the solid line in FIG.
Above z, it is regulated by a constant value according to the sound insulation grade. By the way, the sound insulation of the glass plate is remarkably deteriorated by the coincidence effect in the frequency region centered on 2000 Hz as shown by the broken line in FIG. 1 (the valley portion of the broken line in FIG. 1 causes deterioration of the sound insulation by the coincidence effect). Corresponding, indicating that it does not maintain the prescribed sound insulation).

Here, the coincidence effect means that when a sound wave is incident on the glass plate, the transverse wave is conducted on the glass surface due to the rigidity and inertia of the glass plate and the transverse wave and the incident sound resonate with each other. A phenomenon in which transmission occurs.

Conventional laminated glass is excellent in terms of preventing scattering of fragments, but is 2000 Hz in terms of sound insulation.
In the frequency region centered on, the decrease in sound insulation due to the coincidence effect is unavoidable, and improvement of this point is required.

On the other hand, it is known that human hearing has a very high sensitivity in the range of 1000 to 6000 Hz from the equal loudness curve as compared with other frequency regions, and eliminates the deterioration of sound insulation due to the coincidence effect. It turns out that it is extremely important for soundproofing.

In order to improve the sound insulation of the laminated glass, the coincidence effect as described above is relaxed, and the minimum portion of the transmission loss amount caused by the coincidence effect (hereinafter, the transmission loss amount of this minimum portion is referred to as TL value, It is necessary to prevent the decrease of (see 1).

Conventionally, various measures have been proposed as means for preventing a decrease in the TL value, such as increasing the mass of laminated glass, making glass into multiple layers, subdividing the glass area, and improving the glass plate supporting means. However, none of them bring a sufficiently satisfactory effect, and the price is not reasonable enough for practical use.

The demand for sound insulation has been increasing recently, and, for example, as window glass for construction, there has been a demand for one that always exhibits excellent sound insulation without being affected by the change in the outside air temperature every season. There is.

As a prior art of an interlayer film intended to improve the sound insulation of laminated glass, for example, Japanese Patent Laid-Open No. 2297/1990 is proposed.
As described in Japanese Patent Laid-Open No. 42-42, an interlayer film has been proposed which is formed by laminating a resin layer having a glass transition temperature of 15 ° C. or lower and a plasticized polyvinyl acetal film, and which prevents a decrease in sound insulation due to the coincidence effect. There is.

[0012]

It will be appreciated that this interlayer does indeed provide improved sound insulation. However, when different kinds of materials are laminated, there is a problem that optical distortion occurs due to the difference in refractive index between the different materials, and mass transfer occurs at the interface to reduce sound insulation.

The present invention solves the above-mentioned problems of conventional interlayer films, and provides the basics necessary for laminated glass such as transparency, adhesiveness at the resin film interface, impact energy absorption, and adhesiveness with glass. The TL value is increased by mitigating the coincidence effect at around room temperature without impairing the performance, thereby exhibiting excellent sound insulation, optical distortion is improved, and workability in the film alignment process is good. The purpose of the invention is to provide an interlayer film for laminated glass.

[0014]

According to the present invention, an acetal group having 4 to 6 carbon atoms and an ethylene group to which an acetyl group is bonded via an oxygen atom, based on all ethylene groups in the main chain. At least one layer (A) composed of a polyvinyl acetal resin (a) having a mole fraction of 8 to 22 mol% and a plasticizer, an acetal group having 3 or 4 carbon atoms, and an oxygen atom. The molar ratio of the main chain of ethylene groups to which acetyl groups are bonded to all ethylene groups is 4
A layered film of a polyvinyl acetal resin (b) of not more than mol% and at least another layer (B) composed of a plasticizer, which is a layer (A) among layers constituting the layered film.
Is 9 to 25% of the total thickness of the interlayer film, and
It is an interlayer film for laminated glass having a thickness of 0.05 mm or more.

The polyvinyl acetal resins (a) and (b) used in the present invention are obtained by acetalizing polyvinyl alcohol with an aldehyde,
Usually, it has an acetal group, an acetyl group, and a hydroxyl group in the ethylene group of the main chain.

The average degree of polymerization of polyvinyl alcohol, which is a raw material for producing the polyvinyl acetal resins (a) and (b), is preferably 500 to 3000. If the degree of polymerization is less than 500, the penetration resistance of the laminated glass is poor,
On the contrary, if it exceeds 3000, the strength is too high to be normally used as a safety glass. A more preferable degree of polymerization is 1000 to 2500.

In order to obtain the polyvinyl acetal resin (a) in which the acetal group has 4 to 6 carbon atoms, the number of carbon atoms is 4
~ 6 aldehydes, for example, n-butyraldehyde, isobutyraldehyde, n-hexylaldehyde, valeraldehyde, 2-ethylbutyraldehyde and the like are used alone or in appropriate combination, and preferably n-butyraldehyde, isobutyraldehyde, n — Hexylaldehyde. When an aldehyde having a carbon number of less than 4 is used, sufficient sound insulation cannot be obtained, and conversely, an aldehyde having a carbon number of more than 6 is extremely poor in the reactivity of acetalization, and the obtained interlayer film is Does not exhibit sufficient sound insulation near room temperature.

In order to obtain a polyvinyl acetal resin (b) having an acetal group having 3 or 4 carbon atoms, an aldehyde having 3 or 4 carbon atoms such as propionaldehyde, n-butyraldehyde, isobutyraldehyde, etc. may be used alone or Used in combination of two or more.

In the polyvinyl acetal resin (a), the amount of ethylene groups having acetyl groups bonded via oxygen atoms is limited to 8 to 22 mol%. The reason is,
If this amount is less than 8 mol%, the sound insulation of the resulting interlayer film is not sufficiently exhibited, and conversely, if it exceeds 22 mol%, the reactivity of the aldehyde is significantly reduced, and
This is because the transparency of the obtained intermediate film is lowered, and more preferably 10 to 19 mol%.

The amount of ethylene groups to which an acetyl group is bonded via an oxygen atom of the polyvinyl acetal resin (b) is limited to 4 mol% or less. The reason is that if this amount exceeds 4 mol%, the weather resistance is not sufficiently exhibited, and it is more preferably 0 to 2 mol%.

The degree of acetalization of the polyvinyl acetal resin (a) is preferably 40 mol% or more. This is because if the degree of acetalization is less than 40 mol%, the compatibility with the plasticizer is poor and it is difficult to add the plasticizer in an amount necessary for exhibiting sound insulation. A more preferable degree of acetalization is 50 mol% or more.

The degree of acetalization of the polyvinyl acetal resin (b) is preferably 50 mol% or more. If the degree of acetalization is less than 50 mol%, the compatibility with the plasticizer is poor and it is difficult to add the plasticizer in an amount necessary to secure penetration resistance.

In the present invention, as a method for obtaining the polyvinyl acetal resins (a) and (b), for example, polyvinyl alcohol is dissolved in hot water, the obtained aqueous solution of polyvinyl alcohol is kept at a predetermined temperature, and then this is added. The above aldehyde and catalyst are added to proceed the acetalization reaction, and after that, the reaction solution is kept at a high temperature at a predetermined temperature,
There is a method of obtaining a resin powder through various steps of neutralization, washing with water and drying.

Examples of the plasticizer added to the polyvinyl acetal resins (a) and (b) include organic plasticizers such as monobasic acid esters and polybasic acid esters, organic phosphoric acid resins and organic phosphorous acid resins. Phosphoric acid plasticizers and the like are used.

Among the monobasic acid esters, for example, triethylene glycol, butyric acid, isobutyric acid, caproic acid,
A glycol ester obtained by reaction with an organic acid such as 2-ethylbutyric acid, heptanoic acid, n-octylic acid, 2-ethylhexylic acid, pelargonic acid (n-nonyl acid), and decylic acid is preferable. In addition, esters of tetraethylene glycol and tripropylene glycol with the above organic acids are also used.

The polybasic acid ester is preferably, for example, an ester of an organic acid such as adipic acid, sebacic acid, azelaic acid and a linear or branched alcohol having 4 to 8 carbon atoms.

As the phosphoric acid type plasticizer, tributoxyethyl phosphate, isodecyl phenyl phosphate, triisopropyl phosphite and the like are preferable.

More preferred examples of the monobasic acid ester include triethylene glycol di-2-ethyl butyrate, triethylene glycol di-2 ethylhexoate, triethylene glycol dicaproate and triethylene glycol diester. —N-octoate and the like, dibasic acid ester, dibutyl sebacate,
Examples thereof include dioctyl azelate and dibutyl carbitol adipate.

The amount of the plasticizer added to the polyvinyl acetal resin (a) is preferably 35 to 65 parts by weight with respect to 100 parts by weight of the polyvinyl acetal resin (a). This is because if the addition amount is less than 35 parts by weight, sufficient sound insulation cannot be obtained, and conversely, if it exceeds 65 parts by weight, sufficient sound insulation may not be obtained. The more preferable addition amount is 45 to 55 parts by weight.

The amount of the plasticizer added to the polyvinyl acetal resin (b) is preferably 25 to 55 parts by weight with respect to 100 parts by weight of the polyvinyl acetal resin (b). If the amount added is less than 25 parts by weight, the penetration resistance will decrease, and conversely, if it exceeds 55 parts by weight, the plasticizer will bleed out, impairing the transparency of the laminated glass and the adhesion to the glass plate. Sometimes. A more preferable addition amount is 30 to 45 parts by weight.

The laminated structure of the layer (A) and the layer (B) of the laminated film constituting the intermediate film of the present invention is not particularly limited,
The following are exemplified. Two-layer laminated structure of layer (A) / layer (B). Three-layer laminated structure of layer (B) / layer (A) / layer (B) or layer (A) / layer (B) / layer (A). Four-layer laminated structure of layer (A) / layer (B) / layer (A) / layer (B). In a laminated film having three or more layers, the laminated structure may be an asymmetrical structure such as layer (A) / layer (B) / layer (B).

Of these, a particularly preferred laminated structure is layer (B) / layer (A) / layer (B). The reason why the laminated structure of layer (B) / layer (A) / layer (B) is preferable is due to the relative relationship of dynamic viscoelasticity between layer (A) and layer (B). Another reason is that by adopting this laminated structure, good workability comparable to that of the polyvinyl butyral type intermediate film can be obtained in the film processing method.

The total thickness of the interlayer film is preferably 0.3 to 1.6 mm, which is the thickness of a normal interlayer film for laminated glass. The thicker the thickness, the more excellent the sound insulating property is, but in consideration of the minimum penetration resistance required for the laminated glass, the above range is practically preferable.

The thickness of the layer (A) should be 9 to 25% of the total thickness of the intermediate film, and should be 0.05 mm or more. If the thickness of the layer (A) is less than 9% of the total thickness of the interlayer film, a sufficient effect of sound insulation cannot be obtained, and conversely 2
This is because if it exceeds 5%, the optical distortion becomes large and the basic performance required for the laminated glass such as impact energy absorption is impaired. Moreover, the thickness of the layer (A) is 0.05 mm.
If it is less than the above, a sufficient effect of sound insulation cannot be obtained.

When the layer (B) has a plurality of layers, the total thickness thereof is preferably 0.2 mm or more. The reason is 0.
If it is less than 2 mm, the penetration resistance tends to be significantly reduced.

As the method of forming the intermediate film, for example, a method of separately forming the films forming the layer (A) and the layer (B), and a multilayer molding machine for forming the layer (A) and the layer (B) are used. Various methods such as a method of integrally molding by using are adopted.

In order to produce a laminated glass by sandwiching the interlayer film of the present invention between the glass plates, a method generally used for producing a laminated glass is adopted. A method of producing laminated glass by sandwiching and hot pressing is adopted.

[0038]

The interlayer film for laminated glass of the present invention has 4 to 6 carbon atoms in the acetal group, and the ethylene group to which the acetyl group is bonded via an oxygen atom is based on all ethylene groups in the main chain. At least one layer (A) composed of a polyvinyl acetal resin (a) having a mole fraction of 8 to 22 mol% and a plasticizer, an acetal group having 3 or 4 carbon atoms, and an oxygen atom. A polyvinyl acetal resin (b) having a mole fraction of 4 mol% or less of the main chain of ethylene groups having acetyl groups bonded to all ethylene groups, and at least another layer (B) comprising a plasticizer Of the layers constituting the laminated film, the thickness of the layer (A) is 9 to 25% of the total thickness of the intermediate film, and is 0.05 mm or more. ) Makes sound energy more effective Is absorbed by heat energy, and in particular, the decrease in sound insulation due to the coincidence effect in the middle and high temperature range around 2000 Hz is effectively prevented, and the optical distortion, which is one of the problems of the multilayer film, is significantly improved, and The layer (B) retains the basic performance required for laminated glass, such as transparency, weather resistance, impact energy absorption, adhesiveness at the resin layer interface, and adhesiveness with a glass plate, and laminating processability.

[0039]

EXAMPLES The present invention will be described below with reference to examples. Example 1 (1) Preparation of polyvinyl butyral resin (a) and film formation To 2890 g of pure water, 191 g of polyvinyl alcohol having a polymerization degree of 1700 and a saponification degree of 88.1 mol% was added and dissolved by heating. The temperature of the reaction system was adjusted to 12 ° C., and 35 wt% hydrochloric acid 2
The polyvinyl butyral resin was deposited by adding 01 g and 130 g of butyraldehyde. Then, the reaction system was kept at a temperature of 50 ° C. for 5 hours to complete the reaction. Unreacted aldehyde was washed away by washing with excess water, the hydrochloric acid catalyst was neutralized, salts were removed, and drying was performed to obtain polyvinyl butyral resin (a).

The degree of acetalization of this polyvinyl butyral resin (a) (measured by the proton NMR method) is 6
It was 0.2 mol%. The amount of acetyl groups in this polyvinyl butyral resin (a) was 11.9 mol%.

The obtained polyvinyl butyral resin (a)
(50 g) was collected and 25 g of triethylene glycol di-2-ethylbutyrate as a plasticizer and tetrakis [methylene-3- (3 ', 5'-butyl-4'-hydroxyphenyl) propionate as an antioxidant were collected. ] 0.15 g of methane was added, and this mixture was sufficiently kneaded with a mixing roll, and a predetermined amount of the kneaded product was fed with a press molding machine to obtain 15
Hold at 0 ° C for 30 minutes. Thus, a layer (A) having a thickness of 0.08 mm was formed.

(2) Preparation of polyvinyl acetal resin (b) and film formation To 2910 g of pure water, 190 g of polyvinyl alcohol having a degree of polymerization of 1700 and a degree of saponification of 99.1 mol% was added and dissolved by heating. The temperature of the reaction system was adjusted to 12 ° C., and 35 wt% hydrochloric acid 2
The polyvinyl butyral resin was deposited by adding 01 g and 124 g of butyraldehyde. Then, the reaction system was maintained at a temperature of 50 ° C. for 4 hours to complete the reaction. Unreacted aldehyde was washed away by washing with excess water, the hydrochloric acid catalyst was neutralized, salts were removed, and drying was carried out to obtain polyvinyl butyral resin (b).

The degree of acetalization of this polyvinyl butyral resin (b) (measured by the proton NMR method) is 6
It was 6.3 mol%. The amount of acetyl groups in this polyvinyl butyral resin (b) was 0.9 mol%.

The obtained polyvinyl butyral resin (b)
(50 g) of triethylene glycol-di-2-ethylbutyrate as a plasticizer and 0.1 g of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole as an ultraviolet absorber are added to This mixture was thoroughly kneaded with a mixing roll, and a predetermined amount of the kneaded product was held at 150 ° C. for 30 minutes with a press molding machine. Thus, a layer (B) having a thickness of 0.15 mm was formed. (3) Preparation of laminated glass One layer (A) and two layers (B) are laminated to form a layer (B)
/ Layer (A) / layer (B) so that it is 3
Sandwich it from both sides with two 0 cm square 3 mm thick float glass, put it in a rubber bag, degas for 20 minutes at a vacuum degree of 20 torr, and then transfer it to an oven at 90 ° C in a degassed state. This temperature was maintained for 30 minutes. Then, the pressure is 12kg in the autoclave.
/ Cm ^{2 at} a temperature of 135 ° C., and the interlayer film is a layer (B) / layer (A) / layer (B) (layer thickness ratio: 0.15 / 0.
A transparent laminated glass having a constitution of 08 / 0.15) was obtained.

Example 2 The procedure of Example 1 was repeated except that the layer (A) had a thickness of 0.05 mm and the layer (B) had a thickness of 0.17 mm.
The interlayer film is a layer (B) / layer (A) / layer (B) (layer thickness ratio: 0.
A transparent laminated glass having a constitution of 17 / 0.05 / 0.17) was obtained.

Example 3 The interlayer film was formed in the same manner as in Example 1 except that the layer (A) had a thickness of 0.04 mm, the layer (B) had a thickness of 0.1 mm, and had a five-layer structure. (B) / layer (A) / layer (B) /
Layer (A) / Layer (B) (Layer thickness ratio: 0.1 / 0.04 / 0.
A transparent laminated glass having a constitution of 1 / 0.04 / 0.1) was obtained.

Comparative Example 1 The interlayer film was the layer (B) / layer in the same manner as in Example 1 except that the thickness of the layer (A) was 0.2 mm and the thickness of the layer (B) was 0.1 mm. (A) / layer (B) (layer thickness ratio: 0.1
A transparent laminated glass having a structure of /0.2/0.1) was obtained.

Comparative Example 2 The procedure of Example 1 was repeated except that the layer (A) had a thickness of 0.13 mm and the layer (B) had a thickness of 0.13 mm.
The interlayer film is a layer (B) / layer (A) / layer (B) (layer thickness ratio: 0.
13 / 0.13 / 0.13) was obtained.

Comparative Example 3 The procedure of Example 3 was repeated except that the layer (A) had a thickness of 0.1 mm and the layer (B) had a thickness of 0.06 mm.
The intermediate film is layer (B) / layer (A) / layer (B) / layer (A) / layer (B) (layer thickness ratio: 0.06 / 0.1 / 0.06 / 0.1).
A transparent laminated glass having a structure of /0.06) was obtained.

The sound insulation and optical distortion of the laminated glass obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were measured. The results are shown in Table 1. The sound insulation and optical distortion of the laminated glass were measured as follows. Sound insulation measurement method The laminated glass of the sample was vibrated by a commonly used damping test device, and the transmission loss was calculated from the loss coefficient obtained from it and the ratio of the resonance frequency of the sample and the glass. The measurement temperature was 20 ° C. Optical distortion A laminated glass of a sample was irradiated with a light source that passed through a slit with a halogen lamp, the projection distortion reflected on the screen was passively passed through a sensor (camera), and data processing was performed on a personal computer to obtain the optical distortion value. .

[0051]

[Table 1]

As is clear from Table 1, in the cases of Examples 1 to 3 of the present invention, in all cases, the sound insulation was excellent and the optical distortion was improved, while Comparative Examples 1 to 1 In the case of 3, the optical distortion is large.

[0053]

EFFECT OF THE INVENTION Since the interlayer film for laminated glass of the present invention has the above-mentioned constitution, it has transparency, weather resistance, impact energy absorption, adhesiveness at the resin layer interface, and adhesiveness with a glass plate. The basic performance required for laminated glass, such as for example, and the workability of laminating are maintained, the sound insulation is excellent, and the optical distortion is small.

[0054]

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a minimum value (TL value) of a transmission loss amount caused by a coincidence effect.

Claims (1)

[Claims] 1. An acetal group having 4 to 6 carbon atoms,
Moreover, the mole fraction of the ethylene group in which the acetyl group is bonded through the oxygen atom to the total ethylene group of the main chain is 8 to
22 mol% of at least one layer (A) comprising a polyvinyl acetal resin (a) and a plasticizer, an acetal group having 3 or 4 carbon atoms, and an acetyl group bonded through an oxygen atom. A laminated film of a polyvinyl acetal resin (b) having a mole fraction of 4% by mole or less with respect to all ethylene groups in the main chain of ethylene groups, and at least another layer (B) comprising a plasticizer, Among the layers constituting the laminated film, the thickness of the layer (A) is 9 to 25% of the thickness of the entire intermediate film, and is 0.05 mm or more.