JP5503566B2 - Laminated glass interlayer film and laminated glass - Google Patents

Description

Although the present invention uses inexpensive esterified glycerol as a plasticizer, it does not cause bleed out, has high transparency, excellent penetration resistance, and causes foaming even under high temperature and high humidity. The present invention relates to an interlayer film for laminated glass.

Laminated glass is safe because it does not scatter glass fragments even if it is damaged by an external impact. Therefore, laminated glass is widely used as window glass for automobiles, railway vehicles, aircraft, buildings, and the like.
As a laminated glass, a laminated glass in which an interlayer film for laminated glass containing a polyvinyl acetal resin and a plasticizer is interposed between a pair of glasses and is integrated is generally used (for example, Patent Document 1).

In the interlayer film for laminated glass, the plasticizer has a role of plasticizing polyvinyl butyral resin to improve penetration resistance and to exhibit sound insulation by suppressing vibration.
As the plasticizer, for example, organic ester plasticizers such as monobasic organic acid esters and polybasic organic acid esters, phosphoric acid plasticizers such as organic phosphoric acid plasticizers, and organic phosphorous acid plasticizers are commonly used. Yes. However, these plasticizers are generally expensive, and have been one of the causes of cost increase in the production of interlayer films for laminated glass. In particular, in the interlayer film for laminated glass having improved sound insulation, a large amount of plasticizer is blended, so that an inexpensive plasticizer has been demanded.

As a relatively inexpensive plasticizer, esterified glycerol obtained by esterifying a hydroxyl group of glycerol with a fatty acid is known. However, when esterified glycerol is blended in a polyvinyl acetal resin as a plasticizer, there is a problem that the plasticizer tends to bleed out. Due to this problem, the use of esterified glycerol as a plasticizer for interlayer films for laminated glass has hardly been studied so far.

JP 05-186250 A

Although the present invention uses inexpensive esterified glycerol as a plasticizer, it does not cause bleed out, has high transparency, excellent penetration resistance, and causes foaming even under high temperature and high humidity. An object of the present invention is to provide an interlayer film for laminated glass that does not have any.

The present invention is an interlayer film for laminated glass containing a polyvinyl acetal resin and a plasticizer, wherein the polyvinyl acetal resin has a hydroxyl group content of 28 mol% or more, and the plasticizer has the following formula: It is an interlayer film for laminated glass which is a partially esterified glycerol obtained by esterifying the hydroxyl group of glycerol represented by (1) with 2-ethylhexanoic acid by 50 to 70%.
The present invention is described in detail below.

The interlayer film for laminated glass of the present invention contains a polyvinyl acetal resin.
The polyvinyl acetal resin has a hydroxyl group content of 28 mol% or more. If the hydroxyl group content of the polyvinyl acetal resin is less than 28 mol%, the plasticizer will bleed out. The preferable lower limit of the hydroxyl group content of the polyvinyl acetal resin is 29 mol%, the more preferable lower limit is 30 mol%, the preferable upper limit is 38 mol%, and the more preferable upper limit is 35 mol%.

In addition, the content rate of the hydroxyl group of polyvinyl acetal resin is the molar fraction calculated | required by remove | dividing the amount of ethylene groups which the hydroxyl group has couple | bonded with the total amount of ethylene groups of a principal chain. The amount of ethylene groups to which hydroxyl groups are bonded can be determined, for example, by measuring the amount of ethylene groups to which hydroxyl groups of polyvinyl alcohol as a raw material are bonded using JIS K 6726 “Testing methods for polyvinyl alcohol”.

Although the acetylation degree of the said polyvinyl acetal resin is not specifically limited, A preferable minimum is 0.1 mol% and a preferable upper limit is 20 mol%. When the acetylation degree of the polyvinyl acetal resin is less than 0.1 mol%, the water resistance of the interlayer film for laminated glass obtained may be lowered. When the acetylation degree of the polyvinyl acetal resin exceeds 20 mol%, the penetration resistance of the laminated glass may be lowered. The minimum with more preferable acetylation degree of the said polyvinyl acetal resin is 0.3 mol%.
The degree of acetylation is the value obtained by subtracting the amount of ethylene groups to which acetal groups are bonded and the amount of ethylene groups to which hydroxyl groups are bonded from the total amount of ethylene groups in the main chain. This is a value expressed as a percentage of the mole fraction obtained by dividing by the base amount.

Although the said polyvinyl acetal resin is not specifically limited, Since the adhesive force with respect to glass is excellent, it is preferable that it is a polyvinyl butyral resin.
The degree of butyralization of the polyvinyl butyral resin is not particularly limited, but the preferred lower limit is 63 mol% and the preferred upper limit is 73 mol%. When the degree of butyralization of the polyvinyl butyral resin is less than 63 mol%, the water resistance of the interlayer film for laminated glass obtained may be lowered. When the degree of butyralization of the polyvinyl butyral resin exceeds 73 mol%, the penetration resistance of the laminated glass may be lowered. The more preferable lower limit of the degree of butyralization of the polyvinyl butyral resin is 67 mol%, and the more preferable upper limit is 70 mol%.
The degree of butyralization is a value obtained by dividing the mole fraction obtained by dividing the amount of ethylene groups to which the butyral group is bonded by the total amount of ethylene groups in the main chain, as a percentage. The amount of ethylene group to which a butyral group is bonded can be measured using, for example, JIS K 6728 “Testing method for polyvinyl butyral”.

The polyvinyl acetal resin can be usually produced by acetalizing polyvinyl alcohol.
The polyvinyl alcohol can be usually produced by saponifying polyvinyl acetate.
Although the average degree of polymerization of polyvinyl alcohol used as the raw material of the said polyvinyl acetal resin is not specifically limited, A preferable minimum is 1000 and a preferable upper limit is 4000. When the average degree of polymerization of the polyvinyl alcohol is less than 1000, the penetration resistance of the obtained laminated glass may be lowered. When the average polymerization degree of the polyvinyl alcohol exceeds 4000, the rigidity of the obtained polyvinyl acetal resin becomes too large, so that it may be difficult to mold the interlayer film for laminated glass. The minimum with a more preferable average degree of polymerization of the said polyvinyl alcohol is 1300, and a more preferable upper limit is 3700. In particular, when the average degree of polymerization of the polyvinyl alcohol is 1500 to 2000, an interlayer film for laminated glass having excellent penetration resistance and moldability can be obtained.

The interlayer film for laminated glass of the present invention contains partially esterified glycerol obtained by partially esterifying the hydroxyl group of glycerol represented by the above formula (1) with a fatty acid as a plasticizer.
As a result of intensive studies, the present inventor has used a partially esterified glycerol partially esterified with a specific fatty acid in a specific range in combination with the polyvinyl acetal resin, so that an intermediate for laminated glass without a plasticizer bleedout is obtained. It was found that a film was obtained.

The fatty acid used for the partial esterification reaction is 2-ethylhexanoic acid. By combining partially esterified glycerol obtained by using 2-ethylhexanoic acid in the above partial esterification reaction with a polyvinyl acetal resin having a hydroxyl group content of 28 mol% or more, there is no bleeding out of the plasticizer. An interlayer film for laminated glass can be obtained.

The lower limit of the degree of esterification of the partially esterified glycerol is 50%, and the upper limit is 70%. If the degree of esterification is less than 50%, bleed-out may not be sufficiently suppressed, and penetration resistance of the resulting laminated glass is lowered. When the degree of esterification exceeds 70%, the transparency of the interlayer film for laminated glass obtained is lowered. The preferable lower limit of the degree of esterification of the partially esterified glycerol is 52%, and the preferable upper limit is 68%.
The degree of esterification of the partially esterified glycerol is a value expressed as a percentage of the ratio of partially esterified hydroxyl groups to the total of partially esterified hydroxyl groups and non-partially esterified hydroxyl groups. .

The partially esterified glycerol may be a mixture of partially esterified glycerol and non-partially esterified glycerol.

The content of the partially esterified glycerol in the interlayer film for laminated glass of the present invention is preferably 5 parts by weight with respect to 100 parts by weight of the polyvinyl acetal resin, and 70 parts by weight with respect to the preferable upper limit. If the content of partially esterified glycerol is less than 5 parts by weight, the resulting interlayer film for laminated glass may become too hard and the handleability may be reduced. Penetrability may be inferior. A more preferable lower limit of the content of the partially esterified glycerol is 10 parts by weight, and a more preferable upper limit is 60 parts by weight.

The interlayer film for laminated glass of the present invention may contain a plasticizer other than the partially esterified glycerol as long as the solution of the problem of the present invention is not inhibited.
Examples of the plasticizer other than the partially esterified glycerol include a diester compound.

Examples of the diester compound include triethylene glycol-di-2-ethylhexanoate (3GO), tetraethylene glycol-di-2-ethylhexanoate (4GO), and triethylene glycol-di-2-ethylbutyrate. (3GH), tetraethylene glycol-di-2-ethylbutyrate, tetraethylene glycol-di-n-heptanoate, triethylene glycol-di-n-heptanoate, pentaethylene glycol-di-2-ethylhexanoate, octa And ethylene glycol-di-2-ethylhexanoate, nonaethylene glycol-di-2-ethylhexanoate, decaethylene glycol-di-2-ethylhexanoate, tetraethylene glycol-di-n-octanoate, etc. It is done. Of these, triethylene glycol-di-2-ethylhexanoate (3GO) and tetraethylene glycol-di-2-ethylhexanoate (4GO) are preferable.

The interlayer film for laminated glass of the present invention is a metal salt containing Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, etc. for the purpose of reducing the adhesion between the glass and the interlayer film for laminated glass. , Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba and the like may contain an organic acid ester. When the above metal salt or organic acid ester is not contained in the interlayer film for laminated glass, the adhesive strength between the interlayer film for laminated glass and the glass becomes too strong, so that the penetration resistance of the laminated glass is sufficiently obtained. There may not be.

The interlayer film for laminated glass of the present invention may contain additives such as an ultraviolet absorber, an antioxidant, a light stabilizer, a pigment, a dye, a colorant, and an infrared absorber as necessary.

The infrared absorber is not particularly limited as long as it has the ability to shield infrared rays, but tin-doped indium oxide particles, antimony-doped tin oxide particles, zinc oxide particles doped with elements other than zinc elements, lanthanum hexaboride particles , Zinc antimonate particles, infrared absorbers having a phthalocyanine structure, and the like.

The thickness of the interlayer film for laminated glass of the present invention is not particularly limited, but a preferable lower limit is 0.3 mm and a preferable upper limit is 1.5 mm. When the thickness of the interlayer film for laminated glass of the present invention is less than 0.3 mm, the penetration resistance of the interlayer film for laminated glass may be reduced, and when it exceeds 1.5 mm, the thickness suitable for the laminated glass is reduced. It may exceed. The more preferable lower limit of the thickness of the interlayer film for laminated glass of the present invention is 0.5 mm, and the more preferable upper limit is 1.35 mm.

The interlayer film for laminated glass of the present invention may be a single-layer interlayer film for laminated glass or an interlayer film for laminated glass having a multilayer structure in which two or more resin films are laminated.

The method for producing the interlayer film for laminated glass of the present invention is not particularly limited. For example, after kneading the partially esterified glycerol, the optional additive, and the polyvinyl acetal resin, the interlayer film for laminated glass is formed. Examples of the method include molding.
The kneading method is not particularly limited, and examples thereof include a method using an extruder, a kneader, a Banbury mixer, a calender roll, and the like.
The molding method is not particularly limited, and examples thereof include an extrusion method, a calendar method, and a pressing method.

A laminated glass in which the interlayer film for laminated glass of the present invention is sandwiched between two transparent plates is also one aspect of the present invention.
The manufacturing method of the laminated glass of this invention is not specifically limited, A conventionally well-known manufacturing method can be used.

The said transparent plate is not specifically limited, The transparent plate glass generally used can be used. Specific examples thereof include inorganic glass such as float plate glass, polished plate glass, mold plate glass, meshed plate glass, wire-containing plate glass, colored plate glass, heat ray absorbing plate glass, heat ray reflecting plate glass, and green glass. Moreover, organic plastics boards, such as a polycarbonate and a polyacrylate, can also be used.

The two transparent plates may be the same type of transparent plate or different types of transparent plates. Examples of the combination of different kinds of transparent plates include a combination of a transparent float plate glass and a colored plate glass such as green glass, and a combination of an inorganic glass and an organic plastic plate.

When using the laminated glass of this invention as glass for motor vehicles, it can be used as a windshield, a side glass, a rear glass, and a roof glass.

According to the present invention, despite the use of inexpensive esterified glycerol as a plasticizer, bleeding does not occur, the transparency is high, the penetration resistance is excellent, and foaming is possible even under high temperature and high humidity. An interlayer film for laminated glass that does not occur can be provided.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
(1) Preparation of interlayer film for laminated glass A partially esterified glycerol obtained by esterifying the hydroxyl group of glycerol with 50% of 2-ethylhexanoic acid as a plasticizer was prepared.
40 parts by weight of the partially esterified glycerol, 0.2 part by weight of 2,6-di-t-butyl-p-cresol (BHT) as an antioxidant, and 0.1 UV absorber (TINUVIN 109, manufactured by BASF) A plasticizer solution was prepared by stirring 1 part by weight at 30 ° C. for 1 hour.

The total amount of the plasticizer solution was added to 100 parts by weight of polyvinyl butyral resin (average polymerization degree 1700, butyralization degree 68.5 mol%, acetylation degree 0.9 mol%, hydroxyl group content 30.6 mol%). The mixture was sufficiently mixed and extruded using an extruder so as to have a film thickness of 0.9 mm to produce an interlayer film for laminated glass. At this time, for the purpose of adjusting the adhesive strength of the interlayer film for laminated glass, an aqueous magnesium acetate solution was added so that the Mg concentration in the interlayer film for laminated glass was 40 ppm.
The obtained interlayer film for laminated glass was stored for 24 hours under conditions of constant temperature and humidity of 23 ° C. and a relative humidity of 25%.

(2) Production of laminated glass The obtained interlayer film for laminated glass was sandwiched between two transparent float glasses (length 300 mm × width 300 mm × thickness 2.5 mm) to form a laminated body. The obtained laminated body was temporarily pressure-bonded using a 230 ° C. heating roll. The temporarily bonded laminated glass was pressure bonded for 20 minutes under the conditions of 135 ° C. and pressure 1.2 MPa using an autoclave to produce a laminated glass.

(Examples 2 to 5, Comparative Examples 1 and 2)
An interlayer film for laminated glass and a laminated glass were produced in the same manner as in Example 1 except that the degree of esterification of partially esterified glycerol was as shown in Table 1.

(Evaluation)
The following evaluation was performed about the laminated glass manufactured in the Example and the comparative example.
The results are shown in Table 1.

(1) Bleed-out evaluation The surface of the obtained interlayer film for laminated glass was marked by marking two lines in the vertical and horizontal directions using a red oily magic. The marked interlayer film for laminated glass was placed so that the main surface thereof was located in a plane parallel to the vertical direction, and the interlayer film for laminated glass was allowed to stand at 15 ° C. for 1 month.
One month later, by visually confirming whether or not the bleeding and sagging of the marking due to the bleed-out plasticizer has occurred, it is evaluated whether or not the plasticizer has blitted out on the surface of the interlayer film for laminated glass. did. “O” indicates no bleeding or sagging in any of the four marked lines, and no plasticizer bleedout occurs, and soaking or sagging in any of the four marked lines And a case where a plasticizer bleedout occurred was evaluated as “x”.

(2) Measurement of visible light transmittance Based on JIS R 3106, the visible light transmittance (%) of the obtained laminated glass was measured using a spectrophotometer ("U-4000" manufactured by Hitachi, Ltd.). did.

(3) Measurement of haze value Based on JIS K 7105, the haze of the obtained laminated glass was measured using the Tokyo Denshoku Co., Ltd. haze meter (TC-HIII).

(4) Penetration resistance evaluation The obtained laminated glass (length 300 mm x width 300 mm) was adjusted so that the surface temperature was 23 ° C. Next, in accordance with JIS R 3212, a hard sphere having a mass of 2260 g and a diameter of 82 mm was dropped from the height of 4 m onto the center portion of the laminated glass. The same evaluation was performed for six laminated glasses, and the case where the hard sphere did not penetrate within 5 seconds after the hard sphere collided was regarded as acceptable for all the six laminated glasses. If the number of laminated glasses in which the hard sphere did not penetrate within 5 seconds after the collision of the hard sphere was 3 or less, it was rejected. When the number of the laminated glasses that did not penetrate the hard sphere within 5 seconds after the collision of the hard spheres, the penetration resistance evaluation was again performed on the 6 laminated glasses. If there are 5 laminated glasses that did not penetrate the hard sphere within 5 seconds after the collision of the hard sphere, add another new laminated glass, and the hard sphere will not penetrate within 5 seconds after the collision. The case was accepted. In the same manner, from a height of 5 m, a hard sphere having a mass of 2260 g and a diameter of 82 mm was dropped on the center of the laminated glass with respect to six laminated glasses, and the penetration resistance was evaluated.

(5) Foaming evaluation The obtained laminated glass (length 300 mm × width 300 mm) was held in a constant temperature bath at 80 ° C. and 95% relative humidity for 1 month in a vertical state. The number of foaming produced in the laminated glass after holding for 1 month was observed visually. The number of foams was counted by classifying into two types: foams with a long side of foam of less than 5 mm and foams of 5 mm or more.

According to the present invention, despite the use of inexpensive esterified glycerol as a plasticizer, bleeding does not occur, the transparency is high, the penetration resistance is excellent, and foaming is possible even under high temperature and high humidity. An interlayer film for laminated glass that does not occur can be provided.

Claims (2)

An interlayer film for laminated glass containing a polyvinyl acetal resin and a plasticizer,
The polyvinyl acetal resin has a hydroxyl group content of 28 mol% or more, and the plasticizer is an esterification of a hydroxyl group of glycerol represented by the following formula (1) with 2-ethylhexanoic acid by 50 to 70%. An interlayer film for laminated glass, which is a partially esterified glycerol obtained by

A laminated glass, wherein the interlayer film for laminated glass according to claim 1 is sandwiched between two transparent plates.