JPH02123103A - Polyvinyl butyral resin - Google Patents

Abstract

PURPOSE:To obtain the subject resin having a specific arrangement of hydroxyl groups and specified degree of butyralization, capable of improved production of an interlayer for laminated glass because of providing the interlayer having reduced self-adhesion in the neighborhood of room temperature. CONSTITUTION:An objective resin prepared by condensation of PVA and butyl aldehyde and having 65-75mol% degree of butyralization obtained by measurement of proton nuclear magnetic resonance spectra, >=3 chain length of residual hydroxyl groups, 6-12mol% heterotactic triad type and 3-5mol% syndiotactic triad type obtained by the same measurement. The above-mentioned resin is obtained, e.g., by adding butyl aldehyde to PVA, carrying out a reaction in the presence of an acid catalyst at a high temperature, then neutralizing, washing and drying the resultant reaction product. In addition PVA as the raw material is preferably one with 800-3000 average polymerization degree and >=95% saponification degree.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a novel polyvinyl butyral resin. Specifically, due to the unique arrangement of hydroxyl groups, when a plasticizer is added to produce a laminated glass interlayer film, the polyvinyl butyral resin remains at room temperature. This invention relates to a polyvinyl butyral resin that can provide a film with reduced adhesion between adjacent interlayer films (hereinafter referred to as self-adherence).

(Prior Art) It is widely known to use a film of plasticized polyvinyl butyral, which is made by adding a plasticizer to polyvinyl butyral resin, as an interlayer film for bonding laminated glass. The plasticized polyvinyl butyral film has excellent adhesive strength, light stability, transparency, and low-temperature flexibility.
It is widely used as an interlayer film for laminated glass for automobiles, aircraft, and architecture.

However, conventional interlayer films for laminated glass have the disadvantage that the films stick to each other during winding after film formation because the film surface is highly self-supporting.In order to prevent such adhesion, the film surface is embossed. In addition, anti-blocking agents such as bicarbonate of soda are sprayed. Therefore, when bonding a conventional interlayer film and glass, a washing process to remove the anti-blocking agent must be carried out beforehand.
It is also necessary to undergo a subsequent drying step to adjust the moisture content of the interlayer film, resulting in poor productivity.

The relationship between the self-adhesiveness of interlayer films and the chain length of the hydroxyl groups in the resin has been well studied, and it is said that resins with long hydroxyl chain lengths have lower self-adhesiveness. The length is evaluated by the half value 11 of the hydroxyl group absorption peak in the infrared absorption spectrum of polyvinyl butyral resin (see Japanese Patent Publication No. 61-46425).

However, what is the chain length of the hydroxyl groups that reduces self-adhesion to an extent that does not substantially reduce productivity, and what chain form is most effective for self-adhesion? However, it has not yet been clarified whether or not this can be reduced.

(Issue 8 to be solved by the invention) The present invention has been made with attention to the above-mentioned circumstances, and its purpose is to determine the relationship between the chain length of hydroxyl groups, their morphology, and self-adhesion. By elucidating the relationship, it is an object of the present invention to provide a novel polyvinyl butyral resin suitable for use in interlayer films of laminated glass, which can further reduce self-sufficiency.

(Means for Solving the Problems) While conducting repeated experiments and research on improving the self-adhesion of interlayer films, the present inventors conducted proton nuclear magnetic resonance spectroscopy of polyvinyl butyral resin and added a plasticizer to the polyvinyl butyral resin. The present invention was completed by discovering the relationship between the creep modulus of elasticity and the self-adhesion of the interlayer film formed by adding the additive.

That is, the polyvinyl butyral resin of the present invention is a condensation product of polyvinyl alcohol and butyraldehyde, and in proton nuclear magnetic resonance spectroscopy,
Among those whose degree of butyralization is in the range of 65 to 75 mol% and the chain length of residual hydroxyl groups is 3 or more in the same measurement, the heterotactic triad type is 6 to 12 mol%,
And the syndiotactic triad type is 3 to 5 mol %, thereby achieving the above object.

The polyvinyl butyral resin of the present invention can be obtained, for example, by adding butyraldehyde to polyvinyl alcohol, reacting or aging it under an acid catalyst at a high temperature, and then neutralizing it, washing it with water, and drying it by a conventional method. More specifically, butyraldehyde is added to a polyvinyl alcohol aqueous solution adjusted to 20 to 60'C, and this mixed solution and a catalyst such as hydrochloric acid are kept at a temperature range of 60 to 95°C. The present invention can be obtained by dropping the mixture into hot water to react, followed by post-treatment as described above. Alternatively, a polyvinyl butyral resin may be obtained by adding a catalyst such as hydrochloric acid to an aqueous polyvinyl alcohol solution, dropping butyraldehyde in a cooled state to cause a reaction, then aging at a predetermined temperature, and then post-processing as described above. good. In the production of the above-mentioned polyvinyl butyral resin, the average degree of polymerization of the raw material polyvinyl alcohol is preferably 800 to 3,000, and the saponification degree is preferably 95 mol % or more in order to obtain a polyvinyl butyral resin with good transparency.

In this way, in proton nuclear magnetic resonance spectrometry, among those whose degree of butyralization is in the range of 65 to 75 mol% and whose chain length of residual hydroxyl groups is 3 or more in the same measurement, the heterotactic triad type is determined. 6-12
A polyvinyl butyral resin having a syndiotactic triad form of 3 to 5 mol % is obtained. The proportion of total hydroxyl groups is usually about 20-34.9 mol%.

The obtained polyvinyl butyral resin is mixed with a plasticizer to produce an interlayer film for laminated glass.

The degree of butyralization of the above polyvinyl butyral resin is 65
When the degree of butyralization of the resin is lower than 75 mol %, the compatibility with the plasticizer is poor, and when the degree of butyralization of the resin is higher than 75 mol %, various performances such as penetration resistance are deteriorated when laminated glass is formed.

The above-mentioned plasticizer may be any one that is generally used as a plasticizer for polyvinyl butyral resin, such as triethylene glycol di(2-ethyl butyrate), triethylene glycol di(2-ethylhexoate), etc. etc. are preferably used. The amount of plasticizer added is 30 to 60 parts by weight per 100 parts by weight of polyvinyl butyral resin.
Parts by weight are preferred.

If the amount of plasticizer added is less than 30 parts by weight, the penetration resistance of the laminated glass will decrease, and if it exceeds 60 parts by weight, the plasticizer will ooze out to the surface of the interlayer film, a so-called bleed phenomenon, which will cause the interlayer film for laminated glass to deteriorate. It has a negative effect on transparency and adhesion when used.

Generally, however, as the elasticity (hardness) of polyvinyl butyral resin increases, its self-sufficiency decreases. On the other hand, in the butyralization reaction, it is impossible to completely butyralize polyvinyl alcohol, and the structure of the resulting polyvinyl butyral resin is thought to be mainly a mixture of vinyl butyral groups and vinyl alcohol groups. and,
If these arrangements differ, the physical properties of the polyvinyl butyral resin will change, and the properties of the interlayer film produced as described above, such as self-adhesion, will change.

In the present invention, as a result of investigating the relationship between the arrangement of hydroxyl groups (mol% of heterotactic triad type and syndiotactic triad type) of the above-mentioned polyvinyl butyral resin, the elastic modulus of the interlayer film, and self-sufficiency, The present invention was completed by discovering the relationship between proton nuclear magnetic resonance spectroscopy of polyvinyl butyral resin and the creep modulus and self-adhesion of an interlayer film made by adding a plasticizer to the polyvinyl butyral resin.

That is, in proton nuclear magnetic resonance spectrometry, among those whose degree of butyralization is in the range of 65 to 75 mol% and the chain length of residual hydroxyl groups is 3 or more in the same measurement, the heterotactic triad type is 6 to 12. mole%
By using a polyvinyl butyral resin having a syndiotactic triad type of 3 to 5 mol %, an interlayer film for laminated glass with low self-adhesion can be obtained. This is because polyvinyl butyral resin, in which the hydroxyl groups of vinyl alcohol groups are arranged in a chain, has stronger association through hydrogen bonds than polyvinyl butyral resin in which the hydroxyl groups are arranged in an irregular manner, resulting in increased hardness. Among the hydroxyl groups, resins that contain the heterotactic triad type and syndiotactic triad type arrangement shown in Figure 1 in the above-mentioned predetermined proportions have more hydrogen bonds between molecules, and as a result, have more hardness. It is considered that an interlayer film with reduced self-sufficiency can be obtained. If the proportion of the above-mentioned heterotactic triad type or syndiotactic triad type is too high, the heat-melting properties of the resin will be poor;
This will reduce the workability of the process of laminating and vitrifying the interlayer film.

(Example) The present invention will be explained in detail below based on examples.

In the present invention, proton nuclear magnetic resonance spectra were measured as follows.

A 2% by weight solution of polyvinyl butyral resin in deuterated dimethyl sulfoxide (DMSO-dh) was prepared, and a small amount of tetramethylsilane ((CH3)4S1) was added to the solution.
It was added as a substance and the spectra were measured at 28°C. An example of this is shown in FIG.

The horizontal axis in the figure is the chemical shift (ppm) based on the resonance frequency of tetramethylsilane, which is the standard substance used.
), and the vertical axis is the resonance absorption intensity, which corresponds to the amount of protons (hydrogen). From this measurement chart, the degree of butyralization, the hetero form, and the syndio form of the hydroxyl group were calculated by applying the following calculation formula from the attribution and integrated intensity of each absorption peak listed in Table 1.

Table 1 <Calculation formula> Degree of butyralization (Di) = (21a/(3111-
41A))
a) (Mole χ)' to form hydroxyl M = (IC-IE
) x (3os/2iA) (mol χ) Creep elasticity was measured as follows.

Add 40 g of plasticizer [triethylene glycol di(2-ethyl butyrate)] to 100 g of polyvinyl butyral resin.
After the mixture was added and kneaded for 7 minutes at 70°C using a 6-inch roll, it was press-molded at 150°C for 50 minutes to create a uniform film with a surface thickness of about 0.8m+++.

A rectangular test piece with a width fOmm and a length of 80 mm was prepared from this film. Mark lines are placed at 40 mm intervals on this test piece, and if the measurement temperature is 20°C, 480g
Apply a load of 154g in the case of 154g and Log in the case of 80''C, measure the elongation after leaving it in an atmosphere at the specified temperature for 30 minutes, and calculate the creep modulus (g/c1a) = C load (g) x initial Calculated as cross-sectional area (cJ)/elongation (%).

Furthermore, the self-adhesion strength (1° type peel strength) was measured as follows.

0 created using the same method as for creep modulus measurement described above.
, width 30mm, length 10 from 8mm press film
A rectangular test piece of 0 M was cut out, two pieces were placed one on top of the other, and the test pieces were left in a desiccator kept at a temperature of 20'C for 48 hours under a load of 6 kg. One end of the test piece thus obtained was peeled off from each other.

After bending the peeled film in a 90° direction to make it into a T-shape, both ends of the peeled film were grabbed with a tensile tester, and the T-shaped peel strength was measured at 20°C with a tensile strength of 500 mm/min. was measured.

330 g of polyvinyl alcohol having a degree of saponification of 98.7 mol % and a degree of polymerization of 1450 was dispersed in 3440 g of distilled water and dissolved by heating to prepare an aqueous polyvinyl alcohol solution.

Add 28g of concentrated hydrochloric acid to this and cool to 18°C.
49.1 g of butyraldehyde was added dropwise while stirring.

Furthermore, when the above solution was cooled and 126.5 g of butyraldehyde was added at 12°C, a white resin was precipitated. Then, 205g of concentrated hydrochloric acid was added and while stirring,
After raising the temperature to 70°C at a heating rate of C/hour, the mixture was maintained at that temperature for 3 hours for aging. The obtained resin was cooled, neutralized with sodium bicarbonate, washed with water, and dried according to a conventional method to obtain a white powder.

330 g of polyvinyl alcohol having a degree of saponification of 99.5 mol % and a degree of polymerization of 1450 was dispersed in 2885 g of distilled water and dissolved by heating to prepare an aqueous polyvinyl alcohol solution.

Next, the polyvinyl alcohol aqueous solution was cooled to 30° C., and 186 g of butyraldehyde was added thereto, followed by stirring and mixing for 10 minutes. This mixed solution and 250 g of 3.6% hydrochloric acid were mixed with 0.2
They were simultaneously dropped into a reaction tank containing 545 g of % hydrochloric acid and maintained at 90°C.

The dripping should be completed at the same time in 90 minutes.
The temperature was maintained for 0 minutes. Thereafter, the liquid was cooled, neutralized, washed with water, and dried according to a conventional method to obtain a white powder.

2; Town ≦ Snow Jf! 1-fi! I 3- A polyvinyl butyral resin was obtained in substantially the same manner as in Example 2, except that polyvinyl alcohol with a degree of saponification of 99.2 mol % and a degree of polymerization of 1720 was used and 201 g of butyraldehyde was added. However, the temperature for dropping the mixed solution and hydrochloric acid is 80°C.
The temperature was maintained for 120 minutes after the completion of the dropwise addition.

In Example 1, the degree of saponification was 98.7 mol%, and the degree of polymerization was 1.
Using 450% polyvinyl alcohol, the aging temperature was 50%.
A polyvinyl butyral resin was obtained in the same manner as in Example 1 except that the temperature was changed to °C.

In Example 3, the temperature of the hydrochloric acid to be dropped was 9.0%, the temperature of the hydrochloric acid in the reaction tank was 0.5%, and the dropping temperature was 45°.
A polyvinyl butyral resin was obtained in the same manner as in Example 3 except that C was used.

Table 2 shows the measurement results of the degree of butyralization, mol% of hydroxyl groups, creep modulus, and T-peel strength of the resins obtained in the above Examples and Comparative Examples.

(Margins below) (Effects of the Invention) The polyvinyl butyral resin of the present invention can reduce self-adhesion as described above, and when winding a laminated glass interlayer film made using this resin, the film It can reduce stickiness among comrades.

Therefore, unlike conventional methods, there is no need to emboss the membrane surface or spray anti-blocking agents such as bicarbonate of soda.
The productivity of laminated glass interlayer films can be improved.

Figure 1 (a) is a schematic diagram showing the three-dimensional structure of a hetero-type hydroxyl chain, Figure 1 (b) is a schematic diagram showing the three-dimensional structure of a syndio-type hydroxyl chain, Figure 2 1 is a diagram showing an example of a proton nuclear magnetic resonance spectrum of polyvinyl butyral resin.

that's all

Claims (1)

[Claims] 1. A condensation product of polyvinyl alcohol and butyraldehyde, which has a degree of butyralization in the range of 65 to 75 mol% in proton nuclear magnetic resonance spectroscopy, and a chain length of 3 residual hydroxyl groups in the same measurement. Among the above, 6 to 12 heterotactic triad types
A polyvinyl butyral resin having a syndiotactic triad form of 3 to 5 mol%.