JPH0971443A - Interlayer for safety laminated glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an interlayer excellent in penetration resistance over a wide range of temperatures, good in adhesivity to glass surface, and capable of reducing disasters due to glass fragments when a laminated glass using the interlayer is broken, by incorporating a specific modified polyvinyl acetal with a plasticizer. SOLUTION: This interlayer for safety laminated glass contains a modified polyvinyl acetal(PVA) which has vinyl acetal units in the molecule and 2-20C hydroxyalkyl groups on the side chains which are required for lying bound directly to the main chain. In this case, it is preferable that each of the hydroxyalkyl groups is present in the form of an olefin unit containing this hydroxyalkyl group such as 3-butene-1-ol. The content of the hydroxyalkyl groups in the PVA is pref. 0.1-20mol%. The viscosity-average molecular weight and acetalization degree of the PVA are pref. 100-20,000 and 50-80mol%, respectively. This interlayer comprises 100 pts.wt. of the modified PVA and 20-80 pts.wt. of a plasticizer (e.g. triethylene glycol-di-2-ethyl butyrate).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an interlayer film for safety laminated glass.

[0002]

2. Description of the Related Art Conventionally, polyvinyl alcohol (hereinafter referred to as PV
Polyvinyl acetal obtained by acetalizing (abbreviated as A), especially polyvinyl butyral, is plasticized by adding a plasticizer and is further molded into a sheet, which is used for window glass of automobiles, aircrafts or buildings. Widely used as an interlayer film for laminated glass. However, in recent years, the demand for the strength of safety laminated glass has increased more and more, and in particular, the conventional products obtained by using the polyvinyl acetal obtained by acetalizing ordinary polyvinyl alcohol are excellent in penetration resistance at low temperature or high temperature. There is a problem that the decrease is large, and many studies have been made on the resin for the interlayer film and additives to the resin for improving this point, but no satisfactory one has been found.

[0003]

DISCLOSURE OF THE INVENTION The present invention overcomes the drawbacks of the conventional interlayer films for safety laminated glass as described above, and has excellent penetration resistance in a wide temperature range from low temperature to high temperature. It is intended to provide an intermediate film for use.

[0004]

As a result of intensive studies to solve the above problems, the present inventors have made a safety laminated glass composed of a modified polyvinyl acetal having a side chain of a hydroxyalkyl group having 2 to 20 carbon atoms. The inventors have found an intermediate film for use and completed the present invention.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The modified PVA used as a raw material for the modified polyvinyl acetal of the present invention is required to have a vinyl alcohol unit in the molecule and has a hydroxyalkyl group having 2 to 20 carbon atoms. To the side chain, and the side chain needs to be directly bonded to the main chain of the modified PVA. The hydroxyalkyl group of the modified PVA has 2 to 20 carbon atoms, preferably 2 to 15 and more preferably 3 to 10. The hydroxyalkyl group is an alkyl group having at least one hydroxyl group (hydroxyl group), and has an ω value in terms of thermal stability and water solubility.
-Hydroxylalkyl groups are more preferred. As the alkyl group of the hydroxyalkyl group, its hydrogen atom may be substituted with a linear or branched alkyl group having 1 to 9 carbon atoms.

The hydroxyalkyl group having 2 to 20 carbon atoms is preferably present in the form of an olefin unit containing a hydroxyalkyl group. Among the olefin units containing a hydroxyalkyl group, modified PVA
3-butene-1 from the viewpoint of ease of controlling the degree of polymerization of
-Ol, 4-penten-1-ol, 5-hexene-
1-ol, 7-octen-1-ol, 9-decene-
Monomer units derived from 1-ol, 11-dodecen-1-ol, 3-methyl-3-buten-1-ol and the like are preferable. In addition to these monomer units, it may be a monomer unit containing an ester group capable of generating a hydroxyl group during the saponification reaction of the polyvinyl ester polymer, which is a raw material of the modified PVA.

The content of the hydroxyalkyl group having 2 to 20 carbon atoms in the modified PVA is preferably 0.1 to 20 mol%, more preferably 0.5 to 15 mol%, 1
It is more preferably from 10 mol%. The saponification degree of the modified PVA is not particularly limited, but is preferably 50 mol% or more,
70 mol% or more is more preferable. The viscosity average degree of polymerization of the modified PVA (hereinafter abbreviated as the degree of polymerization) is 100 to
20000 is preferable, 200-8000 is more preferable, 300-3000 is more preferable.

As a method for producing a modified PVA, a polyvinyl ester polymer obtained by copolymerizing a vinyl ester and an olefin having a hydroxyalkyl group having 2 to 20 carbon atoms is saponified in an alcohol or dimethylsulfoxide solution. A known method such as a method of Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, and the like, with vinyl acetate being preferred. By acetalizing the modified PVA obtained by the above method,
The modified polyvinyl alcohol acetalized resin (modified polyvinyl acetal) of the present invention is obtained. Among the modified polyvinyl acetals, modified polyvinyl butyral is preferred. For the acetalization of the modified PVA, the same method as the conventional method for producing polyvinyl acetal is used.
In addition to the above method, the modified polyvinyl acetal of the present invention can be obtained by simultaneously performing a saponification reaction and an acetalization in the saponification step during the production of the modified PVA.

The degree of acetalization of the modified polyvinyl acetal of the present invention varies depending on the type and amount of the modified PVA used, but is preferably 50 to 80 mol%, more preferably 55 to 70 mol%.

As a method for producing an interlayer film for safety laminated glass using a modified polyvinyl acetal as a raw material, the same method as that for conventional polyvinyl acetal is used. A plasticizer is preferably added to the modified polyvinyl acetal of the present invention, and the plasticizer is preferably 20 to 80 parts by weight, and 40 to 6 per 100 parts by weight of the modified polyvinyl acetal.
0 parts by weight is more preferred. As the plasticizer, usual ones can be used, and for example, triethylene glycol-di-2-ethylbutyrate, triethylene glycol-di-2-ethylhexylate and the like are preferably used. Further, additives such as colorants and silicone oil may be added as appropriate. The interlayer film of the present invention is obtained by molding a modified polyvinyl acetal into a sheet by a conventional method. By sandwiching the obtained interlayer film between glass plates and applying heat and pressure, a safety laminated glass is obtained.

[0011]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In the following, "parts" and "%" are respectively "parts by weight" and "% by weight" unless otherwise specified.
Means

Example 1 1680 g of vinyl acetate and 7-octen-1-ol were placed in a 3 liter polymerization tank equipped with a reflux condenser, a stirrer, a thermometer, a nitrogen inlet and a charging port for a post-addition liquid and a pump. 350 g,
420 g of methanol was charged. While stirring the polymerization solution, the system was replaced with nitrogen and heated, and when the temperature reached a constant temperature of 60 ° C., 2,2′-azobisisobutyronitrile (hereinafter referred to as “AIB
Abbreviated as "N") was added to initiate polymerization. From the start of the polymerization, the polymerization was carried out while analyzing the solid concentration in the system. After 4 hours, the polymerization was stopped by cooling the polymerization tank. The polymerization rate when the polymerization was stopped was 59%. The obtained polymerized paste was dropped into n-hexane to precipitate a polymer. Next, after dissolving the polymer in acetone and performing reprecipitation-purification operation in which it is precipitated in n-hexane three times, it is again dissolved in acetone, added dropwise to distilled water, and purified by boiling.
By drying at 60 ° C., purified polyvinyl vinyl acetate (hereinafter abbreviated as “PVAc”) was obtained. next,
Prepare a 30% methanol solution of purified PVAc to prepare 40
While stirring at 0 ° C., a 10% sodium hydroxide concentration in methanol was added to carry out a saponification reaction for 60 minutes.
After crushing the obtained gel-like material, washing with methanol, 50 ° C
The modified PVA as a white powder was obtained by drying at 18 ° C. for 18 hours. The modified PVA thus obtained had a 7-octen-1-ol unit content of 4.5 mol%, a polymerization degree of 590, and a vinyl acetate unit saponification degree of 80 mol%. The modified PVA10
Parts into 90 parts of water, heat to dissolve under stirring, and then 40 ° C
Cooled down. While stirring at 40 ° C., 6.5 parts of concentrated hydrochloric acid having a concentration of 35% was added, and further 5.2 parts of butyraldehyde was added, whereby a white precipitate of the modified polyvinyl butyral was generated. The reaction was terminated by further aging at 40 ° C. for 4 hours, and the resin was neutralized and washed with water to obtain a modified polyvinyl butyral resin having a butyralization degree of 60 mol%. To 100 parts of this resin was added 50 parts of triethylene glycol-2-ethylbutyrate to plasticize the resin,
Roll kneading at ℃ for 5 minutes, then 140 ℃, 50k
An interlayer film having a thickness of 0.75 mm was prepared under the condition of g / cm ² . This film is a glass plate (thickness 3 mm, width 30
0 mm, length 300 mm) sandwiched between two sheets, 120 ℃,
Laminated under the condition of 10 kg / cm ² to obtain a safety laminated glass. With respect to the obtained safety laminated glass, the penetration resistance and the adhesiveness between the film and the glass were measured. The results are shown in Table 1.

Example 2 The following polymerization was carried out in the same manner as in Example 1 using a 5 liter polymerization tank. 2800 g of vinyl acetate, 300 g of 7-octen-1-ol and 700 g of methanol were charged. While stirring the polymerization solution, the system was replaced with nitrogen and heated, and when the temperature reached a constant temperature of 60 ° C, 33 g of AIBN was added to start the polymerization, and the polymerization rate became 63% after 4.5 hours. At that point the polymerization was stopped. Purified PVA in the same manner as in Example 1.
c is obtained, followed by saponification and purification,
A modified PVA was obtained. The content of 7-octen-1-ol unit in the obtained modified PVA was 8.4 mol% and the degree of polymerization was 51.
0, the degree of saponification of vinyl acetate units was 88 mol%. In the same manner as in Example 1 except that the modified polyvinyl butyral resin obtained by using the modified PVA was used,
I got a safety laminated glass. With respect to the obtained safety laminated glass, the penetration resistance and the adhesiveness between the film and the glass were measured. The results are shown in Table 1.

Example 3 Vinyl acetate 2800 g, 7-octen-1-ol 60 g, AI
Polymerization, saponification and purification were carried out in the same manner as in Example 1 except that the polymerization conditions were changed to BN 2.8 g, polymerization time 4.5 hours, and polymerization rate 40% to obtain a modified PVA.
The modified PVA thus obtained had a 7-octen-1-ol unit content of 1.6 mol%, a polymerization degree of 1740 and a vinyl acetate unit saponification degree of 98.5%. A safety laminated glass was obtained in the same manner as in Example 1 except that the modified polyvinyl butyral resin obtained by using the modified PVA was used. With respect to the obtained safety laminated glass, the penetration resistance and the adhesiveness between the film and the glass were measured. The results are shown in Table 1.

Comparative Example 1 Unmodified PV with a saponification degree of 99.1 mol% and a polymerization degree of 1000
A safety laminated glass was obtained in the same manner as in Example 1 except that the polyvinyl butyral resin obtained by using A was used. With respect to the obtained safety laminated glass, the penetration resistance and the adhesiveness between the film and the glass were measured. The results are shown in Table 1.

[0016]

[Table 1]

(* 1) Falling ball height: An edge of a safety laminated glass sample (width 300, length 300 mm) is fixed to a support frame and held horizontally, and a 2.26 kg steel ball is placed on the supporting frame to make a test piece. Free fall in the center. The height of the steel balls was changed in 0.5 m units, and the maximum steel ball height at which the penetration of the steel balls was prevented was measured in 50% of the number of tests in repeated tests at a constant height. This test measures the temperature of safety laminated glass
It carried out about three levels of temperature of 20 degreeC, 20 degreeC, and 40 degreeC. The larger the value of the falling ball height, the higher the penetration resistance. (* 2) Pummel value: The safety laminated glass sample was kept at -18 ° C for 1 hour or more and kept at a constant temperature, then subjected to a hammer (1 pound at the head) crushing test, and the adhered glass particle diameter was 6 mm or less at maximum. Crushed until. The broken glass piece was shaken off, the exposed part of the interlayer film was observed, and the rank was evaluated from 0 to 8. The higher the value of the Pammel value, the lower the exposure. The larger the Pammel value, that is, the lower the degree of exposure, the better the adhesiveness of the interlayer film.

[0018]

INDUSTRIAL APPLICABILITY The safety laminated glass obtained by using the interlayer film for safety laminated glass of the present invention has excellent penetration resistance in a wide temperature range of normal temperature, low temperature and high temperature, and the interlayer film and the glass surface. Since it has good adhesiveness with, it has an effect of reducing the misery of the glass fragments when it is broken by an impact object.

Claims (2)

[Claims] 1. An interlayer film for a safety laminated glass, which is composed of a modified polyvinyl acetal having a side chain of a hydroxyalkyl group having 2 to 20 carbon atoms. 2. An interlayer film for safety laminated glass, which comprises 100 parts by weight of the modified polyvinyl acetal according to claim 1 and 20 to 80 parts by weight of a plasticizer.