JP2021137989A - Laminate - Google Patents

Abstract

To provide a laminate having high penetration resistance and excellent transparency.SOLUTION: A laminate has an intermediate film provided between a glass plate A and a glass plate B, the intermediate film containing cellulose nanofibers, and having a visible light transmittance of 70% or more.SELECTED DRAWING: None

Description

The present invention relates to a laminate and a work safety glass, and more particularly to a laminate applicable to a laminated glass and a work safety glass using the same.

Safety glass is used at manufacturing sites, civil engineering sites, construction sites, etc. to protect workers from flying objects. In addition to the above, the safety glass is also used as, for example, bulletproof glass, security glass, in-vehicle glass for ensuring the safety of occupants on various vehicles, and the like. Laminated glass having penetration resistance is used for such safety glass.

Laminated glass is generally formed by providing a resin film having characteristics according to an application between each of a plurality of glasses. In the laminated glass having the above-mentioned penetration resistance, even if various flying objects collide with each other and the glass is broken, the interlayer film provided between the glasses absorbs the impact and penetrates the flying objects. To prevent. Further, the glass bonded by the interlayer film is hardly scattered by the interlayer film even after being broken, and the bonded state can be maintained.

Such laminated glass is used for various applications such as windshields and side glasses of aircrafts and automobiles, windowpanes of buildings, show windows, water tanks, viewing windows of pools, OA-related equipment, office equipment, and electrical / electronic equipment. It is used. Therefore, the laminated glass is required to ensure safety such as penetration resistance and prevention of scattering of broken glass, and to have excellent transparency.

For example, in Patent Document 1, in a laminated body in which an adhesive interlayer is interposed between substrates and the adhesive is integrated, the adhesive interlayer is a first adhesive resin layer containing polyvinyl butyral resin as a main component and ethylene-. A laminate including a second adhesive resin layer containing a vinyl acetate copolymer resin as a main component has been proposed. In the interlayer film, the excellent properties of PVB (polyvinyl butyral) and EVA (ethylene vinyl acetate) are utilized to improve penetration resistance and transparency.

Japanese Unexamined Patent Publication No. 2004-050750

However, in the laminated body of the PVB layer and the EVA layer, since a plurality of layers are laminated, there is a concern that the thickness becomes thick and the transparency decreases, and the use may be restricted depending on the application.

From the above, the present invention has been made in view of the above, and an object of the present invention is to provide a laminate having high penetration resistance and good transparency.

As a result of diligent studies to solve the above problems, the present inventors have found that the following problems can be solved by the following invention, and have completed the present invention.

That is, the present invention is as follows.
[1] A laminate in which an interlayer film is provided between a glass plate A and a glass plate B, wherein the interlayer film contains cellulose nanofibers and has a visible light transmittance of 70% or more. ..
[2] The laminate according to [1], wherein the content of the cellulose nanofibers in the interlayer film is 0.05 to 3% by mass.
[3] The laminate according to [1] or [2], wherein the visible light transmittance of the interlayer film is 70% or more.
[4] The laminate according to any one of [1] to [3], wherein the interlayer film contains a (meth) acrylic resin.
[5] A work safety glass comprising the laminate according to any one of [1] to [4].

According to the present invention, it is possible to provide a laminate having high penetration resistance and good transparency.

[1. Laminated body]
In the laminate of the present invention, an interlayer film is provided between the glass plate A and the glass plate B, the interlayer film contains cellulose nanofibers, and the visible light transmittance of the laminate is 70% or more. When the visible light transmittance is 70% or more, sufficient transparency can be ensured as a laminated glass for safety glass. The visible light transmittance is preferably 73% or more, and more preferably 80% or more. Visible light transmittance can be measured by the method described in Examples.
Hereinafter, embodiments of the present invention (the present embodiment) will be described in detail.

(Intermediate membrane)
Excellent penetration resistance can be obtained by containing cellulose nanofibers in the interlayer film. It is considered that this is due to the effect of reinforcing the interlayer film derived from the high strength and high aspect ratio, which are the characteristics of cellulose nanofibers. Further, the visible light transmittance of the interlayer film of 70% or more in the state containing the cellulose nanofibers indicates that the cellulose nanofibers are uniformly dispersed, and the penetration resistance of the entire laminate is high. It can be said that it is uniformly excellent.

Cellulose nanofibers are fibers obtained by defibrating a cellulose raw material to a nano size, and preferably have a cellulose I-type crystal structure. Examples of the crystal structure of cellulose include type I, type II, type III, and type IV, and the type I crystal structure is preferable from the viewpoint of low linear expansion characteristics and good elastic modulus. As the cellulose nanofiber having an I-type crystal structure, it is preferable that the cellulose nanofibers are in the form of powder, such as BiNFi-s manufactured by Sugino Machine Limited, and the surface is treated with an acrylic or alkyl dispersant.
The crystal type and crystallinity of cellulose can be measured by an X-ray diffractometer. The presence or absence of the cellulose I-type crystal structure can be easily determined by the fact that there is a peak near 2θ = 22.6 ° in the X-ray diffraction measurement.

More specifically, the fact that the cellulose constituting the cellulose nanofibers has an I-type crystal structure means that in the diffraction profile obtained by wide-angle X-ray diffraction image measurement, 2θ = 14 to 17 ° and 2θ = 22 to 23. It can be identified by having typical peaks at two positions near °.

The number average fiber diameter of the cellulose nanofibers is preferably 2 to 500 nm, more preferably 2 to 100 nm. The number average fiber length of the cellulose nanofibers is preferably 5 nm to 100 μm, more preferably 100 nm to 10 μm.

The number average fiber diameter is, for example, 50 cellulose nanofibers from a TEM image (magnification: 10000 times) negatively stained with 2% uranyl acetate after casting cellulose nanofibers on a carbon film-coated grid that has been hydrophilized. The fibers are extracted and the average fiber diameter is calculated. Further, the number average fiber length can be obtained in the same manner.

The aspect ratio of the cellulose nanofibers is preferably 20 or more, more preferably 50 to 1000. The aspect ratio can be calculated from the following formula (1) by calculating the number average fiber diameter and the number average fiber length and using these values.
Equation (1): Aspect ratio = number average fiber length (nm) / number average fiber diameter (nm)

The content of the cellulose nanofibers in the interlayer film is an amount that can be in the range where the visible light transmittance of the laminate is 70% or more, and specifically, 0.008 to 4.5 mass in the interlayer film. %, More preferably 0.05 to 3% by mass, and even more preferably 0.1 to 1.5% by mass.

When the content of the cellulose nanofibers in the interlayer film is 0.008 to 4.5% by mass, the visible light transmittance of the interlayer film can be 70% or more. When the visible light transmittance of the interlayer film is 70% or more, the visible light transmittance of the laminate itself is likely to be 70% or more, and high transparency can be obtained. The visible light transmittance of the interlayer film is preferably 80% or more, and more preferably 85% or more.
The visible light transmittance of the laminate and the interlayer film can be measured by the method described in Examples described later.

Preferable examples of the resin constituting the interlayer film include (meth) acrylic resin, vinyl chloride resin, polycarbonate resin, polyester resin, polyurethane resin, polyvinyl butyral resin, ethylene-vinyl acetate resin and the like. Of these, (meth) acrylic resins are preferable from the viewpoint of transparency. The above resins may be used alone or in combination of two or more.
In addition, in this specification, the notation of "(meth) acrylic" shows both "acrylic" and "methacryl" collectively. Similarly, "(meth) acrylate" also collectively indicates both "acrylate" and "methacrylate".

The (meth) acrylic resin is at least a cured (meth) acrylic monomer and / or (meth) acrylic oligomer, but also includes a cured resin composition containing these.

As the (meth) acrylic monomer or (meth) acrylic oligomer, a monomer or oligomer of (meth) acrylic acid ester, a derivative thereof, or a mixture of two or more thereof can be used. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, n-hexyl (meth). Alkyl (meth) acrylates such as acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate, 2-hydroshikiethyl ( Modified (meth) acrylates such as meta) acrylate, 2-hydroshikipropyl (meth) acrylate, hydroxybutyl (meth) acrylate, isobornyl (meth) acrylate, methoxypolyethylene (meth) acrylate, phenoxy (meth) acrylate, ethylene glycol Di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate ) Acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2-hydroxy-1,3-di (meth) acrylate, 2,2-bis [4- (meth) acrylic Loxyethoxyphenyl] Propane, 2-Hydroxy-1- (meth) acryloxi-3- (meth) acryloxipropane, trimethylolpropane tri (meth) acrylate, pentaerythrittri (meth) acrylate, pentaerythrit tetra (meth) ) Polyfunctional (meth) acrylates such as acrylates can be mentioned. As these (meth) acrylic acid esters, those described above may be used alone or in combination of two or more.

A (meth) acrylic resin may be composed of a resin composition in which a rubbery polymer is mixed with the above-mentioned (meth) acrylic acid ester monomer or oligomer.
Examples of the rubbery polymer include conjugated diene rubbers such as (meth) acrylic rubber, polybutadiene, polyisoprene, butadiene-isoprene copolymer, polychloroprene, and styrene-butadiene copolymer, or hydrogenated products thereof; both ethylene and propylene. Olefin-based rubbers such as polymer rubbers, ethylene-propylene-diene copolymer rubbers, ethylene-vinyl acetate copolymer rubbers, and polyisoprene rubbers; silicon rubbers; fluororubbers; thermoplastic elastomers such as polyurethane elastomers and polyester elastomers; etc. Can be mentioned.

Considering the formation of an interlayer film by an injection method as described later, a relatively low molecular weight polymethylmethacrylate (PMMA) is dissolved in the monomers methyl methacrylate (MMA) and glycidyl methacrylate, and further, if necessary. It is preferable to use a so-called acrylic syrup to which an additive such as a polymerization accelerator or a polymerization initiator is added.
Acrylic syrup contains at least a (meth) acrylic monomer or a (meth) acrylic oligomer, is liquid at room temperature, and is cured by a polymerization initiator.

Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, and t-butylperoxy-2-ethyl. Hexanoate, t-amylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, 2,4,4-trimethylbenzylperoxy-2-ethylhexanoate, t- Butylperoxy-isobutyrate, t-butylperoxy-2-ethylhexyl carbonate, t-butylperoxy-3,5,5-trimethylhexanoate, t-amylperoxy-3,5,5-trimethylhexanoate , 1,1,3,3-tetramethylbutylperoxy-3,5,5-trimethylhexanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-butyl Organic peroxides such as peroxyisopropyl carbonate, t-amylperoxybenzoate, t-amylmen hydroperoxide, cyclohexanone peroxide, dicumyl peroxide, and bis (4-t-butylcyclohexyl) peroxydicarbonate Can be mentioned. Further, azo compounds such as 2,2-azobisisobutyronitrile and 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile can be mentioned. These polymerization initiators may be used alone or in combination of two or more as appropriate.

Additives such as a tackifier resin, a thickener, a thixotropic agent, a bulking agent, a filler, and a dispersant are appropriately added to the resin composition constituting the interlayer film as long as the effects of the present invention are not impaired. You may.

The thickness of the interlayer film is preferably 0.1 to 6.0 mm, more preferably 1.0 to 4.0 mm.

(Glass plates A and B)
As the glass plates A and B, transparent ones such as an organic glass plate and an inorganic glass plate can be used. The glass plate A and the glass plate B may be made of the same material or different materials.

(1) Organic glass plate:
Examples of the resin constituting the organic glass plate include polycarbonate resin and polymethylmethacrylate resin because of their high transparency and excellent impact resistance, and among them, the polycarbonate resin is preferable. When the interlayer film is sandwiched between two organic glass plates, these organic glasses may be made of the same material or different materials.

The thickness of the organic glass plate is preferably 0.5 to 15 mm, more preferably 0.7 to 13 mm. When the thickness is 0.5 to 15 mm, good penetration resistance can be obtained while reducing the weight.

(2) Inorganic glass plate:
As the glass plate, those generally used for plate glass and laminated glass can be used, for example, soda lime glass, phosphoric acid glass, borosilicate glass, quartz glass, potash lime glass, lead alkali glass, alumina silicate glass, barium. Examples include glass. Further, from the viewpoint of the strength of the laminated glass, it is preferable to use tempered glass. The method for manufacturing the glass plate is not particularly limited, and a general float glass method or the like is used. When the interlayer film is sandwiched between two inorganic glass plates, these inorganic glasses may be made of the same material or different materials.

The thickness of the glass plate is preferably in the range of 1 mm to 5 mm from the viewpoint of weight reduction. When it is 1 mm or more, the moldability is good and it is hard to crack during processing. On the other hand, if it is 5 mm or less, the weight of the laminated glass can be reduced. From the above points, the range of 1.5 to 4 mm is more preferable.

[2. Laminated body manufacturing method]
The laminate of the present embodiment can be produced by, for example, various bonding methods, but it is preferable to produce it by an acrylic injection method, particularly when the interlayer film contains a (meth) acrylic resin.

In the acrylic injection method, for example, a double-sided adhesive tape serving as a spacer is attached around one surface of one glass plate. Another glass of the same size as the glass on which the spacer is installed is bonded together, and the three sides are bonded to form a space between the two glass plates. The spacer on one of the four sides has a release paper on one side, and the position is the injection hole for the resin liquid. After injecting the prepared resin liquid into the space between the injection hole and the glass plate, the release paper at the position of the injection hole is removed, and a spacer is attached to the glass plate to close the injection hole. Then, it is allowed to stand at 15 to 30 ° C. for 4 to 15 hours to produce a laminate.

Here, in order to satisfactorily disperse the cellulose nanofibers in the interlayer film, it is preferable to add a dispersant such as a coupling agent or an acrylic surfactant to the resin liquid at the time of injection. The dispersant is preferably added in an amount of about 10 to 30 parts by mass with respect to 100 parts by mass of the cellulose nanofibers.

The acrylic injection method as described above has higher drop-off fracture resistance than the PVB film bonding method using an autoclave. In general, fracture is more likely to occur from the interface, and fracture from the inside of the interlayer film is less likely to occur than at the interface. According to the injection method, since it follows the small irregularities of the adhesive surface well, the adhesiveness with the interface is high, and the fracture hardly occurs from the inside of the interlayer film until the fracture occurs.
Therefore, the interlayer film obtained by the acrylic injection method also exerts an excellent effect in the anti-fog test or the moisture resistance test. In addition, it is not necessary to use an autoclave to form an interlayer film, and the productivity is high in that it can be produced at room temperature. In addition, there are advantages that it is easy to color with a pigment and that it can be thickened.

[3. Safety glass for work]
The laminate of the present invention is preferably used, for example, as a work safety glass provided with the laminate.
The machine tool has a peephole (translucent part) for checking the processing status. This peephole must withstand the harsh conditions of deterioration due to scratches from chips on the work piece. On the other hand, since the laminate of the present invention has excellent penetration resistance as described above, even if the glass is broken, scattering damage can be minimized. Since the weight can be reduced, workability can be improved. Therefore, it is most suitable for machine tool applications such as machining centers and lathes.

Next, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

The materials used are shown below.
(1) Acrylic syrup:
Product name: Almatex DC500 manufactured by Mitsui Chemicals, Inc. was used.

(2) Glass plate / inorganic glass plate Float plate glass manufactured by AGC Inc. was used (thickness: 5 mm).
-Organic glass plate A polycarbonate resin plate (trade name: PCMR61600) manufactured by Takiron Co., Ltd. was used (thickness: 5 mm).
(3) Cellulose Nanofibers As the cellulose nanofibers, trade name: BiNFi-s manufactured by Sugino Machine Limited was used. The number average fiber diameter was 50 nm, the number average fiber length was 3 μm, the aspect ratio was 60, and it had a cellulose I-type crystal structure.

[Example 1]
(Preparation of laminate)
A double-sided adhesive tape serving as a spacer was attached around one surface of an inorganic glass plate (500 mm × 1000 mm). As the double-sided adhesive tape, a tape having a thickness of 2.0 mm and a width of 6.0 mm was used. Another organic glass plate of the same size as the inorganic glass plate on which the spacer was installed was bonded together, and the three sides were bonded together to create a space between the two glass plates. The spacer on one of the four sides had a release paper on one side, and the position was a resin liquid injection hole.

After injecting the resin liquid into the space between the injection hole and the glass plate, the release paper at the position of the injection hole was removed, and a spacer was attached to the glass plate to close the injection hole. At this time, for injection, a syringe equipped with an injection needle capable of inserting the space was used, and the injection needle was pierced into the spacer portion to remove excess air. Then, it was allowed to stand at 23 degreeC for 8 hours to prepare a laminated body. The thickness of the interlayer film was 2 mm.

The resin solution was prepared by mixing 20 parts of acrylic syrup and 1 part of cellulose nanofibers and dispersing them with a bead mill (manufactured by Nippon Coke Industries, Ltd.). The dispersion treatment was carried out by using beads having a diameter of 0.3 mm for 40 hours and then using beads having a diameter of 0.1 mm for 40 hours.

With respect to the produced laminated body, the visible light transmittance of the laminated body was measured and the laminated body was evaluated as follows.

(Visible light transmittance of laminated body)
The visible light transmittance in the laminated body was determined using an ultraviolet-visible-infrared spectrophotometer (Hitachi High-Tech Science Co., Ltd. model UH4150). The measurement conditions were based on the visible light transmittance measurement method described in JIS R3106 "Test method for transmittance, reflectance and emissivity of plate glass and calculation method of solar heat gain rate of building plate glass".

(Evaluation of laminated body by penetration resistance test: drop weight impact test)
With reference to EN12417 Annex A, by adding mass to the rear part of the attacking body, the mass of the entire attacking body was set to 8.75 kg, and it collided with the central part of the test body (laminated body) by free fall from any height. .. The dimensions of the test piece were 500 x 500 mm, and the test piece was fixed by sandwiching a region 25 mm from each end of each of the four sides between the test piece support frames.
To control the temperature of the test piece, leave it in a room kept at 23 ° C until just before the test for 4 hours or more, and adjust the ambient temperature of the test piece support frame to 23 ° C to keep the temperature of the test piece constant. rice field. The attack surface to the test body was the inorganic glass surface side, and the number of attacks was one. The impact energy of the initial attacker is set to 450J, and if it passes the evaluation after the test, the impact energy is increased at any step, and if it fails, the impact energy is decreased at any step. The test was conducted. This was repeated, and the boundary of the impact energy that passed multiple times and failed multiple times was defined as the impact resistance energy value. Further, when the result did not meet the above-mentioned requirements, the value of the impact energy generated in the case of passing and the case of not passing was adopted, and the value less than that value was taken as the impact resistance energy value.
The evaluation is rejected if there is a penetration crack (visible crack from one surface to the other surface) or penetration (penetration of the material's aggressor), and buckling / bulging (permanent without cracks). If there was an initial crack (crack that can be seen only on the surface), it was judged as acceptable. The evaluation indexes are as follows. The results are shown in Table 1 below.
<Evaluation index of penetration resistance>
A: Impact-resistant energy value is 550J or more B: Impact-resistant energy value is 500J or more and less than 550J C: Impact-resistant energy value is 450J or more and less than 500J D: Impact-resistant energy value is less than 450J

(Visible light transmittance of interlayer film)
In addition, the visible light transmittance of the interlayer film was measured as follows.
Using an ultraviolet-visible-infrared spectrophotometer (Hitachi High-Tech Science Co., Ltd. model UH4150), the visible light transmittance of a test piece containing only the same interlayer film as in each example was determined. The measurement conditions were based on the visible light transmittance measurement method described in JIS R3106 "Test method for transmittance, reflectance and emissivity of plate glass and calculation method of solar heat gain rate of building plate glass".

(Examples 2 to 5, Comparative Examples 1 to 2)
A laminate was prepared in the same manner as in Example 1 except that the content of the cellulose nanofibers in the resin liquid was changed and the content of the cellulose nanofibers in the interlayer film was changed as shown in Table 1 below. The prepared laminate was measured and evaluated in the same manner as in Example 1. The visible light transmittance of the interlayer film was also measured in the same manner as in Example 1. The results are shown in Table 1 below.

Claims (5)

It is a laminated body in which an interlayer film is provided between the glass plate A and the glass plate B.
The interlayer film contains cellulose nanofibers and contains
A laminated body having a visible light transmittance of 70% or more. The laminate according to claim 1, wherein the content of the cellulose nanofibers in the interlayer film is 0.05 to 3% by mass. The laminate according to claim 1 or 2, wherein the visible light transmittance of the interlayer film is 70% or more. The laminate according to any one of claims 1 to 3, wherein the interlayer film contains a (meth) acrylic resin. A work safety glass comprising the laminate according to any one of claims 1 to 4.