JPH11287797A - Method for evaluating compatibility of polyvinyl acetal resin and intermediate film composition for laminated glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly evaluate the compatibility of a small amount of polyvinyl acetal resin and plasticiser. SOLUTION: In a method, 1-15 pts.wt polyvinyl acetal resin is added to 100 pts.wt plasticiser, and is allowed to go into solution for preparing solution. After that, the temperature of the solution is decreased in an atmosphere at 10-30 deg.C, and temperature when one part of the solution becomes cloudy is measured, thus evaluating the compatibility of the polyvinyl acetal resin and the plasticiser. In this case, the polyvinyl acetal resin is preferably polyvinyl butyral resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for evaluating compatibility between a polyvinyl acetal resin and a plasticizer, and an interlayer film composition for laminated glass defined by the method.

2. Description of the Related Art A windshield is used as a so-called windshield on the front of an automobile, an aircraft or the like. As such a windshield, a laminated glass composed of two opposed plate-shaped glasses and an interlayer film for a laminated glass sandwiched between them is usually used.

As an interlayer film for laminated glass, an interlayer film composition for laminated glass comprising a polyvinyl acetal resin such as polyvinyl butyral resin, a plasticizer and other additives is usually used. In the interlayer film composition for laminated glass, compatibility between the polyvinyl acetal resin and the plasticizer is a major problem.

[0004] That is, if the compatibility between the polyvinyl acetal resin and the plasticizer is poor, when forming the sheet, the plasticizer oozes out of the sheet surface, a phenomenon called bleeding, or the sheet becomes white. There is a problem that the characteristics as an interlayer film for laminated glass are impaired. The compatibility between the polyvinyl acetal resin and the plasticizer is different depending on the type of the plasticizer, and the acetalization ratio of the polyvinyl acetal resin, so that the type of the plasticizer is changed or the degree of acetalization of the polyvinyl acetal resin is changed. Then, the compatibility was evaluated.

As a method for evaluating the compatibility, for example,
As disclosed in JP-A-56-36432, after mixing a polyvinyl acetal resin and a plasticizer, a mixture is molded to prepare a sheet, and whether or not the sheet is whitened is determined from the sheet surface. A method for evaluating whether or not bleeding occurs was generally used.

However, in this compatibility evaluation method,
Since it is necessary to form a sheet by molding a mixture of a polyvinyl acetal resin and a plasticizer, a large amount of the polyvinyl acetal resin and the plasticizer are required, and there is a problem that the evaluation takes time.

[0007]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention makes it possible to use a smaller amount of polyvinyl acetal resin and a plasticizer and evaluate the compatibility thereof in a shorter time than in the past. It is an object of the present invention to provide a method for evaluating the compatibility of a suitable polyvinyl acetal resin with a plasticizer, and an interlayer film composition for laminated glass having excellent compatibility defined by the evaluation method.

[0008]

The method for evaluating the compatibility between a polyvinyl acetal resin and a plasticizer according to the present invention comprises the steps of:
After adding and dissolving 1 to 15 parts by weight of a polyvinyl acetal resin with respect to 0 parts by weight to prepare a solution,
The compatibility of the polyvinyl acetal resin and the plasticizer is evaluated by lowering the temperature of the solution in an atmosphere of 0 ° C. and measuring the temperature at which a part of the solution starts to become cloudy. .

The interlayer film composition for laminated glass of the present invention is based on 100 parts by weight of polyvinyl acetal resin.
An interlayer film composition for laminated glass to which a plasticizer is added in an amount of 20 to 60 parts by weight, based on 100 parts by weight of the plasticizer,
After adding 8 parts by weight of the polyvinyl acetal resin to prepare a solution and then performing evaluation using the compatibility evaluation method, a temperature at which a part of the solution starts to become cloudy (hereinafter also referred to as a cloud point) is obtained. , 50 to 120 ° C. Hereinafter, the present invention will be described in detail.

In the method for evaluating compatibility between a polyvinyl acetal resin and a plasticizer according to the present invention, a solution is prepared by adding and dissolving 1 to 15 parts by weight of a polyvinyl acetal resin with respect to 100 parts by weight of a plasticizer. The polyvinyl acetal resin and the plasticizer to be subjected to the compatibility evaluation method are not particularly limited, and may be, for example, those conventionally used. Especially, as a polyvinyl acetal resin, a polyvinyl butyral resin is preferable.

When a polyvinyl acetal resin is added to and dissolved in a plasticizer to prepare a solution, the solution is usually dissolved by heating to prepare a solution. If the addition amount of the polyvinyl acetal resin is less than 1 part by weight, the cloud point when the temperature of the solution is lowered becomes difficult to understand,
If the amount is more than 15 parts by weight, the viscosity becomes too high, or a problem such as gelation occurs, and it becomes difficult to measure the cloud point. The heating conditions are not particularly limited, but it is preferable to heat the mixture in an oil bath or the like until the temperature reaches 150 ° C. or higher.

After preparing the solution, the temperature of the solution is lowered in an atmosphere of 10 to 30 ° C., and the cloud point is measured.
The compatibility between the polyvinyl acetal resin and the plasticizer is evaluated. That is, as the temperature of the solution is lowered, a separation phenomenon between the polyvinyl acetal resin and the plasticizer occurs, and the solution starts to become cloudy. Therefore, the temperature at which clouding starts, that is, the cloud point is read.

If the rate of decrease in the temperature of the solution is too fast, the temperature in the solution becomes uneven and the cloud point becomes indistinct. On the other hand, if the rate of decrease is too slow, the measurement takes a long time. Since the temperature is too high, the temperature of the solution is lowered in an atmosphere of 10 to 30 ° C.

The determination of the fogging state is usually very easy to understand, so that it can be sufficiently measured by visual observation. In addition, for example, a haze meter is used to determine the haze at predetermined time intervals when the temperature drops. For example, there are a method of measuring, and a method of preparing a limit sample of about five steps, and judging the fogging state by comparing with the sample at the time of visual observation.

According to the method for measuring compatibility according to the present invention,
Using a very small amount of a polyvinyl acetal resin and a plasticizer, the compatibility thereof can be accurately evaluated in a very short time.

The interlayer composition for laminated glass of the present invention comprises:
An interlayer film composition for a laminated glass in which a plasticizer is added in an amount of 20 to 60 parts by weight with respect to 100 parts by weight of a polyvinyl acetal resin, and 8 parts by weight of the polyvinyl acetal resin is added with respect to 100 parts by weight of the plasticizer. After preparing a solution to evaluate the compatibility by the above compatibility evaluation method,
The cloud point is 50 to 120 ° C.

The polyvinyl acetal resin used in the present invention is not particularly limited, and examples thereof include those obtained by a so-called precipitation method. For example, in the case of producing a polyvinyl butyral resin using the above precipitation method, polyvinyl alcohol (PVA) is dissolved in warm water, and the obtained aqueous solution is heated to a predetermined temperature, for example, 0 to 95.
C. and the acid catalyst and butyraldehyde are added to proceed the butyral reaction. Next, the reaction is completed by aging by raising the reaction temperature to complete the reaction, followed by performing a neutralization treatment to generate a precipitate. The precipitate is washed with water and dried to produce a polyvinyl butyral resin.

The polyvinyl alcohol used in the precipitation method preferably has an average degree of polymerization of 500 to 3000, more preferably 1000 to 2500. If the average degree of polymerization is less than 500, the penetration resistance of the laminated glass may decrease, and if the average degree of polymerization exceeds 3000, it becomes difficult to produce a resin film.

The degree of saponification of the polyvinyl alcohol is as follows:
From the viewpoint of transparency and heat resistance, those having a content of 70 mol% or more are preferred. Furthermore, in general, the average degree of butyralization of the polyvinyl butyral resin is preferably 40 to 75 mol%. If the average degree of butyralization is less than 40 mol%, the compatibility with the plasticizer decreases, and the average degree of butyralization becomes 75 mol.
If it exceeds 1%, it takes a long time to produce the polyvinyl butyral resin, which is not preferable.

The plasticizer in the present invention is not particularly restricted but includes, for example, glycols such as triethylene glycol, tetraethylene glycol and tripropylene glycol, butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid,
Examples include diesters with monobasic acids such as n-octylic acid and 2-ethylhexylic acid. Among the diesters, triethylene glycol di-2-ethyl butyrate,
Triethylene glycol di-2-ethylhexoate, triethylene glycol di-2-methylpropanoate, triethylene glycol dicaprylate, triethylene glycol di-n-octoate and the like are preferably used.

If the amount of the plasticizer is less than 20 parts by weight based on 100 parts by weight of the polyvinyl butyral resin,
When the penetrability of the obtained laminated glass is reduced and the added amount of the plasticizer exceeds 60 parts by weight, the bleeding phenomenon occurs and the transparency of the interlayer film is reduced.

On the other hand, those having a cloud point of more than 120 ° C. have extremely poor compatibility, and even if a sheet or the like is formed by molding, a bleeding phenomenon occurs immediately. If there is, since the plasticizing effect is very large, the blocking resistance is poor, or the target mechanical properties are not obtained due to being too soft, and problems such as poor penetration resistance occur. Is limited to

[0023]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 As a plasticizer, triethylene glycol di-2-ethylhexanoate (3GO), triethylene glycol di2
Using ethyl butanoate (3GH), triethylene glycol di-2-methylpropanoate (3GB),
As polyvinyl butyral resin, butyralization degree,
65 mol%, 70 mol% (average degree of polymerization: 17
00, using PVA having a degree of saponification of 99% and produced by a precipitation method).

First, 10 g of a plasticizer was placed in a glass test tube, and then 0.8 g of a polyvinyl butyral resin was added and heated at 170 ° C. to dissolve. Thereafter, the solution was stirred and cooled while measuring the temperature of the solution with a thermocouple, and the temperature at which a part of the solution became cloudy was observed. The results are shown in Table 1 below.

[0026]

[Table 1]

Example 2 The same plasticizer and polyvinyl butyral resin as in Example 1 were used, and 40 parts by weight of a plasticizer was added to 100 parts by weight of polyvinyl butyral resin.
The mixture was mixed by a Labo Plastomill to form an interlayer film composition for laminated glass, formed into a sheet having a thickness of 800 μm, and the following compatibility evaluation and blocking property evaluation were performed.

Evaluation method (1) Evaluation of compatibility The obtained sheet-like molded body was placed in an atmosphere of 23 ° C. and a humidity of 25%, and then the plasticizer bleeding on the surface was blotted with blotting paper. The compatibility was evaluated. The results obtained are shown in Table 2 below.

(2) Evaluation of Blocking Property The obtained sheet-like molded article was cut into a rectangle of 10 mm × 25 mm, and two sheets were stacked. A weight of 2 kg was placed on the sheet, a load was applied, the sheet was left standing for 25 hours, and then pulled. The 180 degree peeling force was measured using a testing machine. This measurement is 3
And the average was determined as follows. The results obtained are shown in Table 3 below. Less than 100 kgf / cm: good blocking property 100 kgf / cm or more: poor blocking property

[0030]

[Table 2]

[0031]

[Table 3]

As is clear from the results of Tables 1 and 2, the results obtained by the above-described compatibility evaluation method of the present invention are clearly different from the results obtained by the conventional compatibility evaluation method. With a cloud point of 120 ° C
In the case of exceeding, bleeding phenomenon was observed.

As is clear from the results in Tables 1 and 3, between the results obtained by the above-described compatibility evaluation method of the present invention and the results obtained by the conventional blocking evaluation method, There was a clear correlation, and those having a cloud point outside the range of 50 to 120 ° C had poor blocking properties.

As is clear from the results shown in Tables 1 to 3, the interlayer film composition for laminated glass of the present invention has a cloud point of 50 to 12 according to the compatibility evaluation method of the present invention.
It was within the range of 0 ° C., and was suitable as an interlayer film composition for laminated glass.

[0035]

The method for evaluating the compatibility between a polyvinyl acetal resin and a plasticizer according to the present invention comprises the above-described structure.
Using a very small amount of a polyvinyl acetal resin and a plasticizer, the compatibility thereof can be accurately evaluated in a very short time. Further, since the interlayer film composition for laminated glass of the present invention has the above-mentioned configuration, it is suitable as an interlayer film composition for laminated glass.

Claims (4)

[Claims] 1. A solution is prepared by adding and dissolving 1 to 15 parts by weight of a polyvinyl acetal resin to 100 parts by weight of a plasticizer, and then lowering the temperature of the solution in an atmosphere of 10 to 30 ° C. A method for evaluating the compatibility between a polyvinyl acetal resin and a plasticizer, wherein the compatibility between the polyvinyl acetal resin and the plasticizer is evaluated by measuring a temperature at which a part of the solution starts to become cloudy. 2. The method for evaluating compatibility according to claim 1, wherein the polyvinyl acetal resin is a polyvinyl butyral resin. 3. An interlayer film composition for laminated glass in which a plasticizer is added in an amount of 20 to 60 parts by weight based on 100 parts by weight of a polyvinyl acetal resin. After preparing a solution by adding a polyvinyl acetal resin, when the compatibility is evaluated by the compatibility evaluation method according to claim 1, a temperature at which a part of the solution starts to become cloudy is 50 to 120 ° C. Interlayer film composition for laminated glass. 4. The interlayer composition for laminated glass according to claim 3, wherein the polyvinyl acetal resin is a polyvinyl butyral resin.