JPH011737A - Photocurable polyvinyl acetal resin interlayer film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photocurable polyvinyl acetal resin interlayer film suitable for use in laminated glass such as automobile windshields and building window glasses.

(Prior art) Conventionally, plasticized polyvinyl butyral with a high degree of polymerization, for example, has been widely used as an interlayer film for laminated glass. , has excellent heat resistance and has satisfactory performance in practical use in this respect.

However, in order to manufacture laminated glass by sandwiching this interlayer film between glasses and heating and pressing it in an autoclave, for example, the temperature at the time of heating and pressing, that is, the processing temperature, must be set to, for example, 150°C. Unless it is set relatively high, good fluidity of the interlayer film cannot be obtained. Manufacturing at such high processing temperatures requires heat-resistant manufacturing equipment, increases equipment costs, consumes a large amount of thermal energy, and reduces productivity per unit time.

In order to improve this, even if the content of plasticizer is increased,
Almost no improvement in fluidity at low temperatures can be expected, but rather leads to oozing of plasticizer and a decrease in heat resistance. Further, when the degree of polymerization of polyvinyl butyral is made relatively low, for example, 650, the processing temperature is lowered to, for example, 60°C, and is improved. However, in this case, the toughness and heat resistance of the interlayer film decreases, making it impossible to obtain a laminated glass with satisfactory performance in practical use.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems with the conventional interlayer film, and aims to improve transparency, adhesiveness, toughness, weather resistance, and heat resistance. The object of the present invention is to provide a photocurable polyvinyl acetal resin interlayer film that has performance equivalent to or better than conventional interlayer films, and can be processed at a lower processing temperature than conventional interlayer films.

(Means for Solving the Problems) The photocurable polyvinyl 7cetal resin j1 old model of the present invention is made of a composition containing a polyvinyl acetal resin, a plasticizer, a curing agent, and a photopolymerization initiator. characterized in that - the above object is achieved.

Therefore, the polyvinyl acetal resin used in the present invention includes polyvinyl formal, polyvinyl acetal, polyvinyl butyral, etc. Polyvinyl butyral has good compatibility with plasticizers and other compounding agents, and has good flexibility at low temperatures. It is suitable for use because it has good adhesive properties. If the degree of polymerization of such polyvinyl acetal resin is too low, blocking will easily occur when a film is formed and rolled up, making peeling difficult. On the other hand, if the degree of polymerization is too high, the fluidity will deteriorate and the processing temperature will become high. The degree of polymerization is generally 500-2000, preferably 500-1
It is said to be 500.

Further, the degree of acetalization is preferably 55 to 80 mol%.

Conventionally known plasticizers can be used as the plasticizer to be added to the above polyvinyl acetal resin, such as triethylene glycol di-2-ethyl butyrate, triethylene glycol di-2-ethylhexoate, and dibutyl sebacate. . If the amount of such a plasticizer is too small, good plasticity and flexibility will not be imparted to the interlayer film.

On the other hand, if the blending amount is too large, a so-called bleed phenomenon occurs in which the plasticizer seeps onto the surface of the interlayer film.

The blending amount of the plasticizer is generally 20 to 60 parts by weight, preferably 30 parts by weight, per 100 parts by weight of the polyvinyl acetal resin.
~50 parts by weight.

Further, as the curing agent, functional acrylic monomers and oligomers, unsaturated esters of polyhydric carboxylic acids, etc. are used. Among the functional acrylic threads, monofunctional ones include 2-ethylhexyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate.

Among functional acrylic monomers and oligomers, difunctional ones include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, Polypropylene glycol di(meth)acrylate, butylene gelicol di(meth)acrylate, neobentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, diglycidyl phthalate (meth)acrylic acid There are esters, etc.

Among functional acrylic monomers, trifunctional ones include pentaerythritol tri(meth)acrylate and trimethylolpropane tri(meth)acrylate, and tetrafunctional ones include tetramethylolmethanetetra(meth)acrylate. ) acrylate, 2,2,5.
5-tetrahydroxymethylcyclopenkune (meth)
There are acrylates, etc.

In addition, as unsaturated esters of polyhydric carboxylic acids, diallyl phthalate, diallyl isophthalate, diallyl maleate, diallyl maleate, diallyl adipate,
Examples include diallyl diglycolate, triallyl cyanurate, and diethylene glycol bisallyl carbonate.

Among these curing agents, pentaerythritoltri (
meth)acrylate, trimethylolpropane tri(
meth)acrylate, tetramethylolmethanetetra(
Trifunctional or higher functional acrylic yarn materials such as meth)acrylate and (meth)acrylic acid ester of 2.2.5.5-tetrahydroxylmethylcyclopentanone are preferably used. The reason for this is that such polyfunctional acrylic monomers have good compatibility with polyvinyl acetal resin, have a high boiling point, do not evaporate at film-forming temperatures, and have excellent reactivity when irradiated with light.

However, C1 these curing agents may be used alone or in combination of two or more. If the blending amount of the curing agent is too small, the toughness and heat resistance of the hardened middle 8 parts after light irradiation will not improve. On the other hand, if the amount is too large, a so-called bleed phenomenon occurs in which the curing agent seeps onto the surface of the interlayer film.

The blending amount of the curing agent is generally 0.1 to 50 parts by weight, preferably 1 part by weight, per 100 parts by weight of the polyvinyl acetal resin.
It is said to be 20 heavy remains.

The photopolymerization initiator to be added to the polyvinyl acetal resin may be any initiator as long as it generates radicals directly or indirectly upon irradiation with light. For example, benzoin, hensifenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, ter
t-Butylanthraquinone, 2,2-dimethoxy-2-
Phenylacetophenone, (1)-hydroxycyclohexylphenylketone, 2-methyl-(, l-(methylthio)phenyl)-2-monophorino (2)-propanone, etc. are used.

Among these photopolymerization initiators, benzoin ethyl ether, benzoin isopropyl ether, (1)-hydroxycyclohexylphenyl ketone, and the like are suitable because they cause less yellowing of the intermediate film after irradiation with light.

These photopolymerization initiators may be used alone or in combination of two or more. Such a photopolymerization initiator is generally used in an amount of 0.0% per 100 parts by weight of the polyvinyl acetal resin.
02 to 5 parts by weight are blended.

Furthermore, in the present invention, a thermal polymerization inhibitor is preferably blended in order to prevent the curing agent blended into the intermediate film from polymerizing during film formation or storage. Such thermal polymerization inhibitors include hydroquinone, P-tert-
butylcatechol, hydroquinone monomethyl ether,
Hydroquinone monoethyl ether, hydroquinone monobutyl ether, etc. are used.

Among these thermal polymerization inhibitors, hydroquinone monomethyl ether is suitable because it causes little yellowing of the intermediate film after film formation. In addition, when blending these thermal polymerization inhibitors, generally 0 parts per 100 parts of polyvinyl acetal resin are added.
．． 1 to 5 parts by weight is blended.

Furthermore, in the present invention, a silane coupling agent may be blended in order to improve the adhesive strength between the interlayer film and the glass. Examples of such silane coupling agents include vinyltrichlorosilane, vinyltriethoxysilane, T-chloropropyltrimethoxysilane, γ-chloropropylmethyldichlorosilane, γ-chloropropylmethyldimethoxysilane, and T-chloropropylmethyljethoxysilane. Silane, γ-aminopropyltriethoxysilane, N-
(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, etc. are used.

When compounding a silane coupling agent such as Gorera, it is generally 0.00 parts by weight per 100 parts by weight of polyvinyl acetal resin.
05 to 5 parts by weight is blended.

Further, in the present invention, adhesion modifiers such as hindered amine light stabilizers, antioxidants, ultraviolet absorbers, colorants, and carboxylic acid metal salts may be added.

The hindered amine light stabilizer does not absorb in the ultraviolet absorption range of the photopolymerization initiator, and improves weather resistance without affecting the curing speed of the interlayer film during ultraviolet irradiation. Such hindered amine light stabilizers include bis(2,2,6,6
-tetramethyl-4-piperidyl) sebacate (Sankyo Kasei, 5anol LS-770), tetrakis (2,
,2,6゜6-tetramethyl-4-hyveridyl)l,2
There is 3.4-butanetetra-carboxylate (Adeka Argus, LA-57).

Examples of antioxidants include 2,6-tert-butyl-P-cresol (commonly known as B■■T), tetrakis-[methylene-3-(3,5-di-tert-butyl-4-
Hydroxyphenyl) propionate comethane (Ciba Geigy, Irganox 1010) and the like are used. In addition, if the absorption range of the UV absorber overlaps with that of the photopolymerization initiator used, the crosslinking and curing speed of the interlayer film during UV irradiation will be slowed down, so the types of UV absorbers that can be used are limited, such as Ciba Geigy Co., Ltd. Product name: Tinuvin
1130 (benzotriazole type) and the like are suitable.

A mixture of polyvinyl acetal resin, a plasticizer, a curing agent, a photopolymerization initiator, and other compounding agents as necessary can be formed by a film forming method such as an extrusion method, a calendar method, a hot press method, or a solvent casting method. This makes it an interlayer film.

For example, when forming a film by extrusion method, 100 to 150
It is possible to form a film at a temperature of ℃. Further, the thickness of the intermediate film is generally about 0.2 to 1.5 tm.

Further, it is preferable that the interlayer film has many irregularities formed on its surface. Forming such irregularities improves deaeration performance when the interlayer film is sandwiched between glass and heated and pressurized, and also improves blocking when the interlayer film is stored by being rolled up. An embossing roll method is suitable for forming a large number of unevenness on the surface of the interlayer film. The average interval of unevenness is 100 to 5
00 μm1 preferably 200 to 300 μm, 10
Point average roughness is 20-100 Ilm, preferably 25
~70 μm. Here, the 10-point average roughness is
This is a value measured in accordance with ISOR468.

Note that it is preferable to attach a separator to the surface of the intermediate film. Such a separator prevents foreign matter from adhering to the surface of the interlayer film, and also prevents blocking when the interlayer film is rolled up.

As the separator, polyethylene film or paper coated with silicone is used.

In this way, the photocurable interlayer film of the present invention is constructed. The interlayer film of the present invention is used, for example, in manufacturing laminated glass.

To manufacture laminated glass, preliminary pressure bonding is first performed. This preliminary pressure bonding can be carried out by sandwiching the interlayer film of the present invention between two pieces of glass, placing it in a rubber bag, heating it to a temperature of, for example, 40 to 80°C, and drawing a vacuum, or using a rubber roll. A method is adopted in which air interposed between the glass and the interlayer film is expelled through the interlayer.

Next, main crimping is performed. This main crimping is performed by placing the pre-crimped laminated glass in an air autoclave, for example,
It is carried out at a temperature of 0-100 °C and a pressure of 3-10 kg/c+A.

After that, the laminated glass that has been properly crimped is irradiated with light.
The interlayer film is crosslinked and cured. Light sources include those that emit light in the ultraviolet to visible range, such as ultra-high, high-pressure, and low-pressure mercury lamps,
A halogen lamp such as 86 is used. The light irradiation time varies depending on the intensity of the light, the type of light source, and the degree of crosslinking curing, but is generally about several tens of seconds to several tens of minutes. In addition, the degree of crosslinking hardening is
It is determined by the gel fraction when dissolved in a good solvent, and the gel fraction is generally about 30 to 70% by weight.

The photocurable interlayer film of the present invention can be used not only as an interlayer film for laminated glass as described above, but also as an interlayer film for preventing gaps between the protective glass of a liquid crystal display board and a liquid crystal cell, and as an interlayer film for preventing gaps between the protective glass of a solar cell and a semiconductor module. It can also be used as an interlayer film for a filling bossotant.

(Function) The photocurable interlayer film of the present invention contains a polyvinyl acetal resin, a plasticizer, a curing agent, and a photopolymerization initiator. Such an intermediate film has not yet been cross-linked and cured, and will be cross-linked and cured later to form a polymer, so that a resin with a relatively low degree of polymerization can be used. When a resin with such a low degree of polymerization is used, combined with the action of the plasticizer, it does not exhibit good fluidity even when heated and pressurized at a relatively low temperature.

Therefore, when molding laminated glass, etc., if the photocurable intermediate 11Q of the present invention is sandwiched between glass and heated and pressurized, it will flow well at a relatively low temperature, adhere evenly to the glass, and release. The mind is also fully taken care of.

Furthermore, when a semi-finished product such as a laminated glass thus obtained is irradiated with an appropriate amount of light, the photopolymerization initiator contained in the interlayer film is excited and radicals are generated. Then, the resin and the curing agent are activated by these radicals, causing a polymerization reaction of the curing agent, and the vinyl acecool portion, vinyl alcohol portion, etc. of the resin and the functional portion of the curing agent that underwent the above polymerization reaction. It is presumed that the molecules react in a complex manner, resulting in cross-linking and curing, resulting in larger molecules with a three-dimensional complex network structure.

(Example) Examples and comparative examples of the present invention are shown below.

Su Keifu D = Polyvinyl butyral with a degree of polymerization of 650 (degree of butyralization 65.0 mol%, residual vinyl alcohol 33.0 mol%)
), and various compounding agents shown in Table 1 were mixed therewith.

This mixture was successfully formed into a film at a relatively low temperature of 110°C using a twin-screw extruder equipped with a T-die mold, and then embossed with an embossing roll to a thickness of 760 μm.
A photocurable interlayer film having a 10-point average roughness of 45 μm was obtained.

This photocurable intermediate film was made into a film with a thickness of 2.5 mm and a thickness of 305 mm.
11 g of alcoholic beverages x 305 ■ Sandwiched between two pieces of float glass, placed in a rubber hog, temperature 50℃, degree of vacuum 700mm
Preliminary pressure bonding was performed using a pneumatic autoclave at a relatively low temperature of 60°C, 5 ktr/cLl.
The laminated glass was finally bonded at a pressure of 1 liter to obtain a transparent, well-flowing and well-adhered laminated glass.

This laminated glass was heated at 170°C using an ultra-high pressure mercury lamp.
0 mJ/cJ (measured with ORCU V 302 A,
The interlayer film of the laminated glass was crosslinked and cured by irradiation with ultraviolet rays in the wavelength range of 320 to 390 nm, peak of 350 nm.

The laminated glass thus obtained was subjected to a penetration resistance test, a heat resistance test, and a crosslinking hardening test. The results are shown in Table 1. Note that each of the above tests was conducted in the following manner.

(1) Penetration resistance test based on ILF ¥ based on JIS R3025, weight 225
A steel ball of g is dropped from a height of 5 m onto the center of the laminated glass, and it is determined whether or not the steel ball has penetrated. However, the test temperature was 40°C.

(2) Heat Resistance Test A test piece of laminated glass (501 m x 50 mm) is held vertically, the glass on one side is fixed and maintained at a constant temperature, and the temperature at which the glass on the other side shifts by 3 ml after 10 days is defined as the heat resistance temperature.

(3) Crosslinking hardening test 2g of the interlayer film was peeled off from the laminated glass, placed in a mixed solvent of 90% ethyl alcohol (by volume) and 10% water (by volume), and shaken for 8 hours to completely remove the dissolved components. This was dissolved, filtered through a 200-mesh wire mesh, and the undissolved components (gel content) on the wire mesh were vacuum-dried at a temperature of 60°C for 5 hours.
The insoluble components (gel fraction) relative to the total weight (2 g) are expressed as gel fraction (, E[ff1%).

Polyvinyl butyral with a polymerization degree of 900 (butyralization degree 65.0 mol%, residual vinyl alcohol 33.0 mol%)
), and various compounding agents shown in Table 1 are added to it,
A laminated glass was obtained under the same conditions as in Example 1 except for the above.

In this case as well, 11
The film could be formed satisfactorily at a temperature of 0°C.

Further, the processing temperature for main compression bonding using an air autoclave was 60° C., which can be considered a relatively low temperature, and good fluidity was exhibited and good adhesion was possible.

The same test as in Example 1 was conducted on the laminated glass. The results are shown in Table 1.

Other than using polyvinyl butyral with a polymerization degree of 2100 (degree of butyralization 65.0 mol%, residual vinyl alcohol 33.0 mol%) and not adding any curing agent, photopolymerization initiator, or thermal polymerization inhibitor. A laminated glass was obtained in the same manner as in Example 1.

In this case, the extrusion temperature by the extruder had to be 170° C., which can be said to be relatively f:i temperature, in order to obtain a good M. In addition, the processing temperature for main compression bonding using an air autoclave was required to be 150° C., which can be said to be a relatively high temperature, in order to obtain good adhesion.

The same test as in Example 1 was conducted on this laminated glass. The results are shown in Table 1.

A laminated glass was obtained under the same conditions as in Example 1, except that no main curing agent, photopolymerization initiator, or thermal polymerization initiator was blended. In this case, as in Example 1, the temperature is 110, which can be said to be relatively low temperature.
The film could be formed satisfactorily at a temperature of °C. Further, the processing temperature for main compression bonding using an air autoclave was 60° C., which can be considered a relatively low temperature, and good fluidity was exhibited and good adhesion was possible.

The same test as in Example 1 was conducted on this laminated glass. The results are shown in Table 1.

In this case, the heat resistance temperature was 60°C, which was poor.

In addition, the penetration resistance test was poor as steel balls penetrated through it.

(The following is a blank space) Table 1 (Effects of the invention) As mentioned above, the photocurable interlayer film of the present invention has polyvinyl 7
It is made of a composition containing a setal resin, a plasticizer, a curing agent, and a photopolymerization initiator, and is crosslinked and cured by light irradiation.
This provides good toughness and heat resistance.

Therefore, the interlayer film before crosslinking and curing can be manufactured using polyvinyl acetal resin with a relatively low degree of polymerization, and in this way, a photocurable interlayer film using a resin with a relatively low degree of polymerization can be When the interlayer film is sandwiched between pieces of glass and heated and pressurized in an autoclave to produce laminated glass, the interlayer film exhibits good fluidity even if the processing temperature is set low.

Therefore, the photocurable interlayer film of the present invention can be processed at a lower processing temperature than conventional interlayer films, and as a result, manufacturing equipment does not need to be heat resistant, and equipment costs can be reduced. In addition, the consumption of flies is reduced, and the productivity per hour is improved.

Furthermore, the photocurable interlayer film of the present invention allows adjustment of toughness and heat resistance by appropriately selecting the types and amounts of the polyvinyl acetal resin, plasticizer, curing agent, and photopolymerization initiator. It is possible to obtain processed products such as laminated glass that have superior strength, toughness, and heat resistance compared to conventional interlayer films.

Claims (1)

[Claims] 1. A photocurable polyvinyl acetal resin interlayer film comprising a composition in which a plasticizer, a curing agent, and a photopolymerization initiator are blended with a polyvinyl acetal resin. 2. The interlayer film according to claim 1, wherein the polyvinyl acetal resin is polyvinyl butyral. 3. The degree of polymerization of polyvinyl acetal resin is 500 to 20
00. The interlayer film according to claim 1 or 2, which is 00. 4. The interlayer film according to claim 1, wherein the curing agent is an acrylic monomer having trifunctionality or more. 5. Claim 1, in which the curing agent is blended in 1 to 20 parts by weight based on 100 parts by weight of the polyvinyl acetal resin.
The interlayer film according to item 1 or 2. 6. The photopolymerization initiator is polyvinyl acetal resin 100
The interlayer film according to claim 1, which is blended in an amount of 0.02 to 5 parts by weight. 7. The interlayer film according to claim 1, wherein a large number of irregularities are formed on at least one side. 8. The 10-point average roughness of the many irregularities is 20 to 100 μm
The interlayer film according to claim 7.