WO2021079886A1 - Resin sheet and method for producing same - Google Patents

Abstract

A resin sheet which contains a resin that comprises from 2.0% by mole to 9.0% by mole of a carboxylic acid unit, from 1.0% by mole to 3.0% by mole of a neutralized carboxylic acid unit and an ethylene unit based on all monomer units constituting the resin, while having a thickness of 0.2 mm or more but less than 3 mm, wherein the insoluble fraction in a mixed solvent having a toluene/acetic acid mass ratio of 75/25 is from 5% by mass to 90% by mass.

Description

Resin sheet and its manufacturing method

The present invention relates to a resin sheet that can be used as an interlayer film for laminated glass and a method for producing the same, an interlayer film for laminated glass made of the resin sheet, and a laminated glass having the interlayer film for laminated glass.

Ionomer, which is a neutralized product of an ethylene / unsaturated carboxylic acid copolymer, is often used as an interlayer film of laminated glass because of its high elastic modulus, transparency, and adhesiveness to glass (for example, Patent Documents). 1). In recent years, the required performance for laminated glass has increased, and even for ionomers, it maintains high transparency regardless of the manufacturing conditions of laminated glass, maintains a high elastic modulus even at high temperatures, and does not reduce the strength of laminated glass. In addition, there is a growing demand for less coloring and better appearance.

Patent Document 2 describes an interlayer film for laminated glass obtained by irradiating a neutralized product of an ethylene / unsaturated carboxylic acid copolymer with ionizing radiation after film molding. Further, Patent Document 3 is a laminated film composed of an ionomer layer of an ethylene / unsaturated carboxylic acid copolymer and a thermosetting resin layer, wherein the ionomer layer is crosslinked with an electron beam. A skin film is described.

U.S. Pat. No. 6432522 Japanese Unexamined Patent Publication No. 60-86057 Japanese Unexamined Patent Publication No. 2000-85062

However, according to the study by the present inventor, it has been found that the interlayer film for laminated glass as in Patent Document 2 does not have sufficient transparency, independence in a high temperature environment, and adhesion to glass. Further, it was found that the laminated film as in Patent Document 3 has a small thickness, so that sufficient strength cannot be obtained, and the degree of cross-linking is too high, so that the adhesive processability at the time of producing laminated glass is inferior.

Therefore, an object of the present invention is a resin sheet having excellent transparency, strength, self-supporting property in a high temperature environment, and adhesive processability, a method for producing the same, an interlayer film for laminated glass made of the resin sheet, and the laminated glass. It is an object of the present invention to provide a laminated glass having an interlayer film for use.

As a result of diligent studies to solve the above problems, the present inventor has found that a resin sheet containing a resin containing a carboxylic acid unit, a carboxylic acid neutralized product unit, and an ethylene unit contains a carboxylic acid unit and a carboxylic acid. The content of the Japanese product unit is 2.0 to 9.0 mol% and 1.0 to 3.0 mol%, respectively, the thickness of the resin sheet is 0.2 mm or more and less than 3 mm, and toluene / acetic acid ( It has been found that the above problems can be solved when the insoluble content in the mixed solvent of (mass ratio) = 75/25 is 5 to 90% by mass, and the present invention has been completed. That is, the present invention includes the following.

[1] 2.0 to 9.0 mol% of carboxylic acid unit, 1.0 to 3.0 mol% of carboxylic acid neutralized product unit, and ethylene unit based on all the monomer units constituting the resin. A resin sheet containing a resin containing the above, having a thickness of 0.2 mm or more and less than 3 mm, and having an insoluble content of 5 to 90% by mass in a mixed solvent of toluene / acetic acid (mass ratio) = 75/25.
[2] The resin sheet according to [1], wherein the storage elastic modulus at 50 ° C. is 50 to 300 MPa, and the storage elastic modulus at 140 ° C. is 0.1 to 2.5 MPa.
[3] When the content of the carboxylic acid unit of the resin sheet is a (mol%) and the insoluble content is b (mass%),
The following equations (1) and (2):
2 ≦ a ≦ 9 (1)
-7.8 × a + 96 ≦ b ≦ 90 (2)
The resin sheet according to [1] or [2], which satisfies the above conditions.
[4] The resin sheet according to any one of [1] to [3], which comprises at least one selected from the group consisting of an ultraviolet absorber and a silane coupling agent.
[5] The resin sheet according to any one of [1] to [4], wherein the content of the resin is 95% by mass or more with respect to the mass of the resin sheet.
[6] An interlayer film for laminated glass made of the resin sheet according to any one of [1] to [5].
[7] A laminated glass having two glass plates and an interlayer film for laminated glass according to [6] arranged between the two glass plates.
[8] The laminated glass according to [7], wherein the laminated glass has a haze of 5.0% or less after heating to 140 ° C. and then slowly cooling to 23 ° C. at a rate of 0.1 ° C./min.
[9] A step of irradiating a raw material sheet containing a resin containing a carboxylic acid unit, a carboxylic acid neutralized product unit, and an ethylene unit with an electron beam having an acceleration voltage of 200 to 5000 kV and an irradiation dose of 10 to 500 kGy. The method for producing a resin sheet according to any one of [1] to [5], which comprises.
[10] When the thickness of the raw material sheet is t (mm), the acceleration voltage is V (kV), and the specific gravity of the raw material sheet is ρ (g / m ³ ).
The following formula (3):
33.4 × V ^5/3 ÷ ρ ≧ t (3)
The method according to [9], which satisfies the above conditions.
[11] When the content of the carboxylic acid unit of the raw material sheet is a'(mol%) and the irradiation dose is c (kGy),
The following equations (4) and (5):
2 ≤ a'≤ 9 (4)
-15 × a'+ 115 ≦ c ≦ 500 (5)
The method according to [9] or [10], which satisfies the above conditions.

The resin sheet of the present invention is excellent in transparency, strength, independence in a high temperature environment, and adhesive processability. Therefore, it can be suitably used as an interlayer film for laminated glass.

[Resin sheet]
The resin sheet of the present invention contains a resin (also referred to as ionomer or resin (x)) containing a carboxylic acid unit (A), a carboxylic acid neutralized product unit (B), and an ethylene unit (C). In the present specification, the "unit" means a "constituent unit of origin", for example, the carboxylic acid unit indicates a structural unit derived from carboxylic acid, and the carboxylic acid neutralized product unit is in carboxylic acid. A structural unit derived from Japanese products is shown, and an ethylene unit indicates a structural unit derived from ethylene.

<Resin>
Examples of the monomer constituting the carboxylic acid unit (A) include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, monomethyl maleate, and monoethyl maleate. Among these, acrylic acid, methacrylic acid, monomethyl maleate, and monoethyl maleate are preferable, acrylic acid and methacrylic acid are more preferable, and methacrylic acid is even more preferable. The carboxylic acid unit can be used alone or in combination of two or more.

The content of the carboxylic acid unit (A) is 2.0 to 9.0 mol% based on all the monomer units constituting the resin. If the content of the carboxylic acid unit (A) is less than 2.0 mol%, the transparency tends to decrease, and if the content exceeds 9.0 mol%, the strength tends to decrease. Therefore, when the content of the carboxylic acid unit (A) is in the above range, transparency and strength can be improved. The content of the carboxylic acid unit (A) is preferably 2.5 mol% or more, more preferably 3.0 mol% or more, still more preferably 4.0 mol% or more, and particularly preferably 5.0 mol% or more. Yes, preferably 8.5 mol% or less, more preferably 8.0 mol% or less. When the content of the carboxylic acid unit (A) is at least the above lower limit, the transparency is more likely to be improved, and when the content is at least the above upper limit, the strength is more likely to be improved.

As the monomer constituting the carboxylic acid neutralized product unit (B), a neutralized product of the monomer constituting the carboxylic acid unit (A) is preferable. The carboxylic acid neutralized product is obtained by replacing the hydrogen ion of the carboxylic acid with a metal ion. Examples of the metal ion include monovalent metals such as lithium, sodium and potassium; and ions of polyvalent metals such as magnesium, calcium, zinc, aluminum and titanium. These metal ions can be used alone or in combination of two or more. For example, it may be a combination of one or more monovalent metal ions and one or more divalent metal ions.

The content of the carboxylic acid neutralized product unit (B) is 1.0 to 3.0 mol% based on all the monomer units constituting the resin. If the content of the carboxylic acid neutralized product unit (B) is less than 1.0 mol%, the transparency and independence in a high temperature environment tend to decrease, and the content is 3.0 mol%. If it exceeds, the melt viscosity during the molding process becomes high, and there is a tendency for coloring. Therefore, when the content of the carboxylic acid neutralized product unit (B) is in the above range, transparency and independence in a high temperature environment can be improved. The content of the carboxylic acid neutralized product unit (B) is preferably 1.5 mol% or more, preferably 2.5 mol% or less. When the content of the carboxylic acid neutralized substance unit (B) is at least the above lower limit, transparency and independence in a high temperature environment are more likely to be improved, and when the content is at least the above upper limit, coloring is performed. It is easy to reduce the degree.

The content of the ethylene unit (C) is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 88 mol% or more, based on all the monomer units constituting the resin, and is preferable. Is less than 97 mol%. When the content of the ethylene unit (C) is at least the above lower limit, the strength and molding processability of the resin sheet are likely to be improved, and when the content is at least the above upper limit, the resin sheet is transparent and under a high temperature environment. It is easy to improve independence and adhesive processability.

The resin sheet of the present invention may contain a structural unit other than the carboxylic acid unit (A), the carboxylic acid neutralized product unit (B), and the ethylene unit (C). Examples of other constituent units include a carboxylic acid ester unit (D) and the like. Examples of the monomer constituting the carboxylic acid ester unit include unsaturated carboxylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and isopropyl (meth) acrylate. N-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, amyl (meth) acrylate, isoamyl (meth) acrylate, (meth) ) N-hexyl acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, pentadecyl (meth) acrylate, dodecyl (meth) acrylate, isobornyl (meth) acrylate, phenyl (meth) acrylate , (Meta) benzyl acrylate, (meth) phenoxyethyl acrylate, (meth) 2-hydroxyethyl acrylate, 2-methoxyethyl (meth) acrylate, glycidyl (meth) acrylate, allyl (meth) acrylate, etc. Examples thereof include (meth) acrylic acid ester, dimethyl itacone, dimethyl maleate, and diethyl maleate. Among these, (meth) acrylic acid ester, especially methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate. , (Meta) acrylate isobutyl, (meth) acrylate sec-butyl, (meth) acrylate t-butyl, (meth) acrylate methyl, (meth) acrylate ethyl, (meth) acrylate n-propyl , (Meta) isopropyl acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate are more preferred, methyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate. More preferably, methyl (meth) acrylate is most preferred. Of the methacrylic acid ester and the acrylic acid ester, the methacrylic acid ester is preferable because it is excellent in heat decomposition and low coloring property. These (meth) acrylic acid esters can be used alone or in combination of two or more. In addition, in this specification, "(meth) acrylic acid" means methacrylic acid or acrylic acid.

The content of the carboxylic acid ester unit (D) is preferably 2.0 mol% or less, more preferably 1.0 mol% or less, based on all the monomer units constituting the resin. The lower limit of the content of the carboxylic acid ester unit (D) is 0 mol% or more, and when the resin contains the carboxylic acid ester unit (D), it is preferably 0.05 mol% or more. When the content of the carboxylic acid ester unit (D) is in the above range, it is advantageous in terms of transparency.

The content of the carboxylic acid unit, the carboxylic acid neutralized product unit, the ethylene unit, and optionally the carboxylic acid ester unit in the resin (x) contained in the resin sheet of the present invention can be analyzed by the following procedure. is there. First, the structural units in the resin can be identified by pyrolysis gas chromatography (pyrolysis GC-MS), and then their contents can be evaluated by using nuclear magnetic resonance spectroscopy (NMR) and elemental analysis. It is also possible to combine IR and Raman analysis. Prior to these analyzes, it is preferable to remove components other than the resin by a reprecipitation method or a Soxhlet extraction method. Since the ratio of the constituent units of the resin contained in the resin sheet is almost the same as the ratio of the raw material resin, the ratio of each constituent unit of the raw material resin may be analyzed and obtained by the above method. For example, it can be obtained by the method described in Examples.

In one embodiment of the present invention, the melting point of the resin (x) is preferably 50 to 200 ° C., more preferably 60 to 180 ° C., and even more preferably 80 to 150 ° C. from the viewpoint of transparency and processability. For the melting point, for example, referring to the method described in JIS K7121: 2012, using differential scanning calorimetry (DSC), the cooling rate is -10 ° C / min, the heating rate is 10 ° C / min, and the melting of the second temperature rise is performed. It can be obtained from the peak picktop temperature.

In one embodiment of the present invention, the heat of fusion of the resin (x) is preferably 0 J / g to 25 J / g from the viewpoint of transparency. For the heat of fusion, for example, referring to the method described in JIS K7122: 2012, using differential scanning calorimetry (DSC), the cooling rate is -10 ° C / min, and the heating rate is 10 ° C / min. It can be calculated from the area of the melting peak of.

In one embodiment of the present invention, the melt flow rate (MFR) of the resin (x) measured under the conditions of 190 ° C. and 2.16 kgf is preferably 0.3 g / 10 minutes or more, more preferably 0.7 g / 10. Minutes or more, more preferably 1.0 g / 10 minutes or more, particularly preferably 2.0 g / 10 minutes or more, preferably 50 g / 10 minutes or less, more preferably 30 g / 10 minutes or less. When the MFR of the resin is in the above range, it is easy to facilitate the molding process in which deterioration due to heat is suppressed. The MFR of the resin can be adjusted by the molecular weight and the content of the carboxylic acid unit (A), the carboxylic acid neutralized product unit (B) and the carboxylic acid ester unit (D).

In one embodiment of the present invention, the degree of branching of the resin (x) per 1000 carbon atoms is not particularly limited, but is preferably 5 to 30, more preferably 6 to 20. The analysis of the degree of branching per 1000 carbons can be performed by the DDMAS method using, for example, solid-state NMR.

<Resin sheet>
The resin sheet of the present invention contains the resin, has a thickness of 0.2 mm or more and less than 3 mm, and is insoluble in a mixed solvent of toluene / acetic acid (mass ratio) = 75/25 (also referred to as mixed solvent (A)). The amount is 5 to 90% by mass. Therefore, the resin sheet of the present invention is excellent in transparency, strength, independence in a high temperature environment, and adhesive processability. In addition, the resin sheet of the present invention can also have excellent roll-windability and low coloration. In the present specification, the self-supporting property in a high temperature environment means that when a resin sheet is used as an interlayer film for laminated glass for laminated glass, even if the glass is broken in a high temperature environment, the broken glass. Means that the resin sheet does not easily penetrate the resin sheet (laminated glass interlayer film) or the resin sheet does not easily drip. Further, the adhesive processability means a property that the glass and the resin sheet are easily adhered to each other when the laminated glass is produced by using the resin sheet as an interlayer film for laminated glass. Further, the degree of coloring indicates the degree of coloring and can be evaluated by, for example, the degree of yellowness (YI). Further, the transparency means that both the transparency of the resin sheet itself and the transparency of the laminated glass formed by using the resin sheet as an interlayer film are included. The insoluble matter in the mixed solvent (A) may be referred to as toluene / acetic acid insoluble matter.

The resin sheet of the present invention has an insoluble content of 5 to 90% by mass in the mixed solvent (A). The resin constituting the resin sheet of the present invention dissolves in the mixed solvent (A) when it is not crosslinked by the electron beam, and as the degree of cross-linking by the electron beam increases, the solubility in the mixed solvent (A) decreases and it is insoluble. The amount becomes large. On the contrary, as the degree of cross-linking by the electron beam decreases, the amount of insoluble matter decreases. Therefore, the amount of insoluble matter in the mixed solvent (A) is an index of the degree of cross-linking of the resin sheet by the electron beam (also referred to as the degree of electron beam cross-linking).

If the amount of the insoluble matter in the mixed solvent (A) of the resin sheet is less than 5% by mass, the degree of electron beam cross-linking is too low, so that crystallization is promoted when the resin sheet is slowly cooled after being prepared as a laminated glass as an interlayer film. It is not possible to obtain sufficient transparency. Further, if the insoluble content of the resin sheet in the mixed solvent (A) exceeds 90% by mass, the elastic modulus at 140 ° C. becomes too high, and sufficient adhesive processability cannot be obtained at the time of producing laminated glass. The resin sheet of the present invention has an insoluble content of 5 to 90% by mass in the mixed solvent (A), and the degree of cross-linking of the resin by an electron beam is adjusted to an appropriate range, so that the resin sheet has sufficient transparency and adhesive processability. Can have. The amount of insoluble matter can be set within a predetermined range by appropriately adjusting the acceleration voltage and irradiation dose of the electron beam in the irradiation step of the resin sheet, for example. As the acceleration voltage and irradiation dose of the electron beam increase, the degree of electron beam cross-linking increases, so that the amount of insoluble matter tends to increase.

The insoluble content of the resin sheet in the mixed solvent (A) is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, preferably 85% by mass or less, and more preferably 75% by mass. % Or less, more preferably 65% by mass or less. When the amount of the insoluble content in the mixed solvent (A) of the resin sheet is at least the above lower limit, the transparency is likely to be improved, and when the amount of the insoluble content is at least the above upper limit, the adhesive processability is likely to be improved. The mass of the insoluble matter is obtained by mixing the resin sheet with the mixed solvent, separating the solid and liquid, taking out the solid layer, vacuum-drying until there is no change in mass, and then measuring the mass. The insoluble content (mass%), which is a ratio, is calculated by the following formula (6):
Mass fraction of toluene / acetic acid insoluble = Ma / Mc × 100 (6)
[In the formula, Mc is the mass (g) of the resin sheet, and Ma is the mass (g) of the toluene / acetic acid insoluble matter].
It can be calculated according to the above, and more specifically, it can be calculated by the method described in the examples.

In one embodiment of the present invention, the resin sheet of the present invention has a carboxylic acid unit content of a (mol%) and an insoluble content of b (mass%).
The following equations (1) and (2):
2 ≦ a ≦ 9 (1)
-7.8 × a + 96 ≦ b ≦ 90 (2)
It is preferable to satisfy. When the formulas (1) and (2) are satisfied, the resin sheet of the present invention tends to exhibit excellent transparency. Specifically, in the resin sheet of the present invention, if the content of the carboxylic acid unit is large, crystallization is likely to be suppressed when the laminated glass using the resin sheet as an interlayer film is manufactured and then slowly cooled, so that the degree of cross-linking is high. Even if it is relatively small, it is easy to ensure transparency. On the contrary, if the degree of cross-linking is large, the crystallization is likely to be suppressed, so that transparency can be easily ensured even if the content of the carboxylic acid unit is small. Therefore, the degree of cross-linking can be optimized according to the content of the carboxylic acid unit. The formula (2) is a formula that optimizes the relationship between the content of the carboxylic acid unit (a mol%) and the insoluble content (b mass%) corresponding to the degree of cross-linking. Further, when the resin sheet of the present invention satisfies the formulas (1) and (2), the optimum amount of carboxylic acid unit and the degree of cross-linking can be balanced in order to exhibit the effect of the present invention. Adhesive processability and independence in a high temperature environment are also likely to improve.

The thickness of the resin sheet of the present invention is 0.2 mm or more and less than 3 mm. If the thickness of the resin sheet is less than 0.2 mm, the strength is not sufficient, and the degree of cross-linking tends to be too high depending on the acceleration voltage of the electron beam, so that sufficient adhesive workability tends not to be obtained. It is in. Further, when the thickness of the resin sheet is 3 mm or more, the transparency and roll winding property of the resin sheet are not sufficient, and the degree of coloring tends to be high. In addition, since irradiation unevenness in the thickness direction tends to occur depending on the acceleration voltage of the electron beam, the degree of electron beam cross-linking tends to vary, and the transparency of the resin sheet and partial coloring tend to occur due to this. There is a tendency. Since the resin sheet of the present invention has a thickness of 0.2 mm or more and less than 3 mm, it can have sufficient transparency, strength, adhesive processability, roll-up property, and low coloring degree.

The thickness of the resin sheet of the present invention is preferably 0.3 mm or more, more preferably 0.5 mm or more, further preferably 0.8 mm or more, preferably 2.5 mm or less, and more preferably 2.0 mm or less. .. When the thickness of the resin sheet is at least the above lower limit, the strength and adhesive processability of the resin sheet are likely to be improved, and when the thickness is at least the above upper limit, the transparency of the resin sheet and the rollability of the roll are improved. In addition to being easy, it is easy to reduce the degree of coloring, and it is easy to suppress variations in transparency and partial coloring. The thickness of the resin sheet can be measured by using, for example, a contact type or non-contact type thickness gauge, and can be measured by, for example, the method described in Examples.

The resin sheet of the present invention has a storage elastic modulus at 50 ° C. of preferably 50 MPa or more, more preferably 70 MPa or more, still more preferably 100 MPa or more, preferably 300 MPa or less, more preferably 250 MPa or less, still more preferably 200 MPa or less. It is as follows. When the storage elastic modulus at 50 ° C. is in the above range, excellent independence in a high temperature environment (for example, about 50 ° C.) is likely to be exhibited. The storage elasticity at 50 ° C. is, for example, the ratio of the carboxylic acid unit (A) and the carboxylic acid neutralized product unit (B) of the resin contained in the resin sheet, particularly the ratio of the carboxylic acid neutralized product unit (B). By appropriately changing it, it can be within a predetermined range. The larger the ratio of the carboxylic acid unit (A) and the carboxylic acid neutralized product unit (B) of the resin, particularly the ratio of the carboxylic acid neutralized product unit (B), the higher the storage elastic modulus at 50 ° C. tends to be.

The resin sheet of the present invention has a storage elastic modulus at 140 ° C., preferably 0.1 MPa or more, more preferably 0.3 MPa or more, still more preferably 0.5 MPa or more, preferably 2.5 MPa or less, more preferably. Is 2.0 MPa or less, more preferably 1.5 MPa or less, and particularly preferably 1.3 MPa or less. When the storage elastic modulus at 140 ° C. is in the above range, excellent adhesive processability at the time of producing laminated glass is likely to be exhibited. The storage elastic modulus can be measured using a dynamic viscoelasticity measuring device under the conditions of a measurement temperature of 50 ° C. or 140 ° C. and a frequency of 1 Hz, and can be measured, for example, by the method described in Examples. The storage elastic modulus at 140 ° C. can be set within a predetermined range by appropriately adjusting the acceleration voltage and irradiation dose of the electron beam in the irradiation step of the resin sheet, for example. As the acceleration voltage and irradiation dose of the electron beam become smaller, the degree of electron beam cross-linking is reduced, so that the storage elastic modulus at 140 ° C. tends to be lower.

In one embodiment of the present invention, the resin sheet of the present invention has a low degree of coloring and is preferably colorless. The yellowness (YI) of the resin sheet of the present invention is preferably 1.0 or less, more preferably 0.8 or less, still more preferably 0.5 or less. When the yellowness (YI) is not more than the above upper limit, it tends to have a low degree of coloring. The lower limit of yellowness (YI) is 0 or more. The yellowness (YI) can be measured in accordance with JIS K7373 based on the value measured in accordance with JIS Z8722 using a colorimetric color difference meter, and can be calculated, for example, by the method described in Examples.

The resin sheet of the present invention is excellent not only in the transparency of the sheet itself, but also in the transparency of the laminated glass formed by using the resin sheet as an interlayer film. The transparency of the laminated glass containing the resin sheet of the present invention as an interlayer film is, for example, the haze (slow cooling) after heating the laminated glass to 140 ° C. and then slowly cooling the laminated glass to 23 ° C. at a rate of 0.1 ° C./min. The slow-cooling haze can be evaluated by (also referred to as a haze), and the slow-cooling haze is the same as the haze described in the section [Interlayer film for laminated glass and laminated glass] described later.

The resin sheet of the present invention preferably has a low water content from the viewpoint of adhesiveness to glass. The water content is preferably 1% by mass or less, more preferably 0.5% by mass or less, still more preferably 0.02% by mass or less, and particularly preferably 0.% by mass, based on the mass of the resin sheet. It is 01% by mass or less.

The content of the resin (x) contained in the resin sheet of the present invention is preferably 95% by mass or more, more preferably 97% by mass or more, still more preferably 99% by mass or more, based on the mass of the resin sheet. .. When the content of the resin (x) is at least the above lower limit, transparency, strength, independence in a high temperature environment and adhesive processability can be easily improved, and the degree of coloring can be easily reduced. The upper limit of the content of the resin is 100% by mass or less.

The resin sheet of the present invention contains an ultraviolet absorber, a silane coupling agent, an antioxidant, an antioxidant, a heat deterioration inhibitor, a light stabilizer, an anti-glue agent, a lubricant, a mold release agent, a polymer processing aid, and a charge. It may contain additives such as inhibitors, flame retardants, dyes and pigments, organic dyes, matting agents and phosphors. Among these, at least one selected from the group consisting of an ultraviolet absorber and a silane coupling agent is preferable.

The ultraviolet absorber is a compound having a function of absorbing ultraviolet rays.

Examples of the ultraviolet absorber include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic acid esters, formamidines and the like. These UV absorbers can be used alone or in combination of two or more.

Benzotriazoles are preferable as UV absorbers because they have a high effect of suppressing deterioration of optical properties such as coloring due to UV exposure. Examples of benzotriazoles include 2- (2H-benzotriazole-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (manufactured by BASF; trade name TINUVIN329), 2- (2H-). Benzotriazole-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (manufactured by BASF; trade name TINUVIN234), 2,2'-methylenebis [6- (2H-benzotriazole-2) -Il) -4-t-octylphenol] (manufactured by ADEKA Co., Ltd .; LA-31), 2- (5-octylthio-2H-benzotriazole-2-yl) -6-tert-butyl-4-methylphenol, etc. Can be mentioned.

As an ultraviolet absorber for triazines, 2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine (manufactured by ADEKA Co., Ltd .; LA-) F70) and its analogs, hydroxyphenyltriazine-based ultraviolet absorbers (manufactured by BASF; TINUVIN477 and TINUVIN460), 2,4-diphenyl-6- (2-hydroxy-4-hexyloxyphenyl) -1,3, 5-Triazine and the like can be mentioned.

Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyldiethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, and N- (2). -Aminoethyl) -3-aminopropyldiethoxysilane and the like. These silane coupling agents can be used alone or in combination of two or more.

A known material can be used as the anti-aging agent. Specifically, hydroquinone, hydroquinone monomethyl ether, 2,5-di-t-butylphenol, 2,6-di (t-butyl) -4-methylphenol, mono (or di or tri) (α-methylbenzyl). ) Phenolic compounds such as phenol; 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 4,4'-thiobis Bisphenol compounds such as (3-methyl-6-t-butylphenol); benzimidazole compounds such as 2-mercaptobenzimidazole and 2-mercaptomethylbenzimidazole; 6-ethoxy-1,2-dihydro-2,2, Amine-ketone compounds such as 4-trimethylquinolin, a reaction product of diphenylamine and acetone, 2,2,4-trimethyl-1,2-dihydroquinolin polymer; N-phenyl-1-naphthylamine, alkylated diphenylamine, octylation Aromatic secondary amine compounds such as diphenylamine, 4,4'-bis (α, α-dimethylbenzyl) diphenylamine, p- (p-toluenesulfonylamide) diphenylamine, N, N'-diphenyl-p-phenylenediamine; Examples thereof include thiourea compounds such as 1,3-bis (dimethylaminopropyl) -2-thiourea and tributylthiourea. These antioxidants can be used alone or in combination of two or more.

The antioxidant is effective in preventing oxidative deterioration of the resin by itself in the presence of oxygen. For example, phosphorus-based antioxidants, hindered phenol-based antioxidants, thioether-based antioxidants, and the like can be mentioned. These antioxidants can be used alone or in combination of two or more. Among them, phosphorus-based antioxidants and hindered phenol-based antioxidants are preferable, and the combined use of phosphorus-based antioxidants and hindered phenol-based antioxidants is more preferable, from the viewpoint of the effect of preventing deterioration of optical properties due to coloring.

When a phosphorus-based antioxidant and a hindered phenol-based antioxidant are used in combination, the amount of the phosphorus-based antioxidant used: the amount of the hindered phenol-based antioxidant used is (1: 5) to mass ratio. (2: 1) is preferable, and (1: 2) to (1: 1) are more preferable.

As phosphorus-based antioxidants, 2,2-methylenebis (4,6-di-t-butylphenyl) octylphosphite (manufactured by ADEKA Corporation; trade name: ADEKA STAB HP-10), Tris (2,4-) Di-t-butylphenyl) phosphite (manufactured by BASF; trade name: IRGAFOS168), 3,9-bis (2,6-di-t-butyl-4-methylphenoxy) -2,4,8,10- Tetraoxa 3,9-diphosphaspiro [5.5] undecane (manufactured by ADEKA Corporation; trade name: ADEKA STAB PEP-36) and the like are preferable.

As hindered phenolic antioxidants, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (manufactured by BASF; trade name IRGANOX1010), octadecyl-3- (3,5-Di-t-Butyl-4-hydroxyphenyl) propionate (manufactured by BASF; trade name IRGANOX1076) and the like are preferable.

The heat deterioration inhibitor can prevent the heat deterioration of the resin by capturing the polymer radicals generated when exposed to high heat under a substantially anoxic state. As the heat deterioration inhibitor, 2-t-butyl-6- (3'-t-butyl-5'-methyl-hydroxybenzyl) -4-methylphenylacrylate (manufactured by Sumitomo Chemical Co., Ltd .; trade name: Sumilyzer GM) ), 2,4-di-t-amyl-6- (3', 5'-di-t-amyl-2'-hydroxy-α-methylbenzyl) phenylacrylate (manufactured by Sumitomo Chemical Co., Ltd .; trade name Sumilizer) GS) and the like are preferable.

The light stabilizer is a compound having a function of capturing radicals mainly generated by oxidation by light. Suitable light stabilizers include hindered amines such as compounds having a 2,2,6,6-tetraalkylpiperidine skeleton.

As the anti-adhesion agent, fatty acid salts or esters, polyhydric alcohol esters, inorganic salts, inorganic oxides, and particulate resins are preferable. Specific examples include calcium stearate, calcium carbonate, calcium sulfate, magnesium sulfate, barium sulfate, silicon dioxide (manufactured by Ebonic; trade name Aerosil), and particulate acrylic resin.

Examples of the lubricant include stearic acid, behenic acid, stearoamic acid, methylene bisstearoamide, hydroxystearic acid triglyceride, paraffin wax, ketone wax, octyl alcohol, and hydrogenated oil.

Examples of the release agent include higher alcohols such as cetyl alcohol and stearyl alcohol; and glycerin higher fatty acid esters such as stearic acid monoglyceride and stearic acid diglyceride.

As the polymer processing aid, polymer particles having a particle size of 0.05 to 0.5 μm, which can be usually produced by an emulsion polymerization method, can be used. The polymer particles may be single-layer particles made of a polymer having a single composition ratio and a single extreme viscosity, or may be multilayer particles made of two or more kinds of polymers having different composition ratios or extreme viscosities. You may. Among these, particles having a two-layer structure having a polymer layer having a low ultimate viscosity in the inner layer and a polymer layer having a high ultimate viscosity of 5 dl / g or more in the outer layer are preferable. The polymer processing aid preferably has an ultimate viscosity of 3 to 6 dl / g. If the ultimate viscosity is too small, the effect of improving moldability tends to be low. If the ultimate viscosity is too large, the moldability of the copolymer tends to be deteriorated.

As the organic dye, a compound having a function of converting ultraviolet rays into visible light is preferably used.

Examples of the fluorescent substance include fluorescent pigments, fluorescent dyes, fluorescent white dyes, fluorescent whitening agents, and fluorescent bleaching agents.

The content of these additives can be appropriately determined within a range that does not impair the effects of the present invention, and is preferably 5% by mass or less, more preferably 3% by mass or less, and further preferably 1% by mass or less. Further, the lower limit of the content of the additive is 0% by mass or more.

The resin sheet of the present invention may be composed of only a layer (also referred to as a layer (x)) containing a resin and optionally an additive, or may be a laminate containing at least one layer (x). .. The laminated body is not particularly limited, and for example, a two-layer body in which a layer (x) and another layer are laminated, a laminated body in which another layer is arranged between the two layers (x), and the like are used. Can be mentioned.

Examples of the other layer include a layer containing a known resin. Examples of the resin include polyethylene terephthalate, polybutylene terephthalate, cyclic polyolefin, and polyphenylene sulfide among polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyurethane, polytetrafluoroethylene, acrylic resin, polyamide, polyacetal, polycarbonate, and polyester. Polytetrafluoroethylene, polysulfone, polyether sulfone, polyarylate, liquid crystal polymer, polyimide, thermoplastic elastomer and the like can be used. In addition, other layers may also contain the additive, if necessary.

[Manufacturing method of resin sheet]
The method for producing the resin sheet of the present invention is not particularly limited, and for example, a raw material sheet containing a resin containing a carboxylic acid unit, a carboxylic acid neutralizer unit, and an ethylene unit has an acceleration voltage of 200 to 5000 kV and an acceleration voltage of 200 to 5000 kV. A method including a step of irradiating an electron beam having an irradiation dose of 10 to 500 kGy (hereinafter, also referred to as an irradiation step) is preferable.

<Manufacturing of raw material resin>
The resin contained in the raw material sheet (also referred to as the raw material resin) is the one before the resin (x) of the present invention is electron-beam crosslinked. Therefore, the constituent units constituting the raw material resin are the same as the constituent units contained in the resin (x), except that they are not crosslinked with an electron beam. That is, the raw material resin may contain the carboxylic acid unit, the carboxylic acid neutralized product unit, the ethylene unit, and optionally the other structural unit (for example, the carboxylic acid ester unit (D)). Further, since the ratio of the structural units constituting the resin can hardly change before and after the electron beam cross-linking, the ratio of each structural unit of the raw material resin (x) is, for example, the ratio of the above-mentioned structural units of the resin (x). You can select from the same range as.

The method for producing the raw material resin is not particularly limited, but for example, after copolymerizing ethylene and a carboxylic acid ester at high temperature and high humidity to obtain an ethylene-carboxylic acid ester copolymer (X), the carboxylic acid ester thereof is obtained. Examples include a method of converting all or part of the units into carboxylic acid units and carboxylic acid neutralized units.
As a method for converting all or part of the carboxylic acid ester unit into the carboxylic acid unit and the carboxylic acid neutralized product unit, all or part of the carboxylic acid ester unit is saponified with an alkali such as sodium hydroxide. After converting to a carboxylic acid neutralized product unit to obtain an ethylene-carboxylic acid neutralized product copolymer or an ethylene-carboxylic acid ester-carboxylic acid neutralized product copolymer, the carboxylic acid neutralized product unit A method of demetallizing a part of the above with an acid to convert it into a carboxylic acid unit (hereinafter, also referred to as method (1)) can be mentioned. Alternatively, the carboxylic acid unit is obtained by converting all or part of the carboxylic acid ester unit into a carboxylic acid neutralized product unit by the above-mentioned saponification, and then demetallizing all the carboxylic acid neutralized product units with an acid. After conversion to, a method of neutralizing a part thereof with an alkali metal or an alkaline earth metal (hereinafter, also referred to as method (2)) can be mentioned.
When all the carboxylic acid ester units of the ethylene-carboxylic acid ester copolymer (X) are converted into carboxylic acid units and carboxylic acid neutralized product units, the ethylene unit, carboxylic acid unit, and carboxylic acid neutralized product unit When a part of the carboxylic acid ester unit is converted into a carboxylic acid unit and a carboxylic acid neutralized product unit, an ethylene unit, a carboxylic acid unit, a carboxylic acid neutralized product unit, and a carboxylic acid ester can be produced. A raw material resin having a unit can be produced.

As the carboxylic acid ester which is the raw material of the above-mentioned production method, for example, the above-mentioned unsaturated carboxylic acid ester can be used. Among these, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, Sep-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate are preferable, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate and the like. (Meta) acrylic acid ester is more preferable. Comparing the methacrylic acid ester and the acrylic acid ester, the methacrylic acid ester is preferable because it is excellent in heat-resistant decomposition and low colorability of the obtained resin. The carboxylic acid ester can be used alone or in combination of two or more.

Specific examples of the ethylene-carboxylic acid ester copolymer (X) include an ethylene-methyl acrylate copolymer, an ethylene-methyl methacrylate copolymer, an ethylene-ethyl acrylate copolymer, and an ethylene-ethyl methacrylate copolymer. Polymer, ethylene-propyl methacrylate copolymer, n-propyl methacrylate copolymer, ethylene-isopropyl methacrylate copolymer, isopropyl methacrylate copolymer, n-butyl ethylene-acrylate Examples thereof include a copolymer, an ethylene-n-butyl methacrylate copolymer, a sec-butyl copolymer of ethylene-acrylate, a sec-butyl copolymer of ethylene-methacrylate, and the like. Commercially available copolymers may be used, or these copolymers may be synthesized with reference to US Patent Application Publication No. 2013/0274424, JP-A-2006-23309, or JP-A-2007-84743. You may.

The content of the carboxylic acid ester unit in the ethylene-carboxylic acid ester copolymer (X) is preferably 3.0 mol% or more, more preferably 3.5 mol% or more, still more preferably 4.0 mol%. The above is preferably 12 mol% or less, more preferably 11 mol% or less, still more preferably 10 mol% or less. When the content of the carboxylic acid ester unit is in the above range, the content of the carboxylic acid unit and the carboxylic acid neutralized product unit of the obtained resin can be easily adjusted to a suitable range.

In one embodiment of the present invention, the melt flow rate (MFR) of the ethylene-carboxylic acid ester copolymer (X) measured at 190 ° C. and 2.16 kgf is preferably 90 g / 10 minutes or more, more preferably. It is 100 g / 10 minutes or more, more preferably 150 g / 10 minutes or more, preferably 400 g / 10 minutes or less, more preferably 350 g / 10 minutes or less, still more preferably 330 g / 10 minutes or less. By setting the MFR of the ethylene-carboxylic acid ester copolymer (X) in the above range, it is easy to achieve both moldability and strength of the obtained resin. The MFR of the ethylene-carboxylic acid ester copolymer (X) can be adjusted by the degree of polymerization of the copolymer and the content of the carboxylic acid ester unit.

In one embodiment of the present invention, the weight average molecular weight (Mw) of the ethylene-carboxylic acid ester copolymer (X) is preferably 15,000 g / mol or more, more preferably 20,000 g / mol or more in terms of polystyrene. More preferably, it is 30,000 g / mol or more, preferably 200,000 g / mol or less, and more preferably 100,000 g / mol or less. The number average molecular weight (Mn) of the ethylene-carboxylic acid ester copolymer (X) is preferably 5,000 g / mol or more, more preferably 10,000 g / mol or more, and further preferably 15,000 g / mol or more. It is preferably 100,000 g / mol or less, and more preferably 50,000 g / mol or less. When the Mw and Mn of the ethylene-carboxylic acid ester copolymer (X) are in the above ranges, the molding processability, strength and independence of the obtained resin in a high temperature environment can be easily improved. The weight average molecular weight and the number average molecular weight _{can be measured using, for example, a column (three series of TSKgel GMH HR-} H (20) HT) at a column temperature of 140 ° C. and a 1,2,4-trichlorobenzene solvent. .. Further, the weight average molecular weight (Mw) of the raw material resin can be selected from the same range as the Mw of the ethylene-carboxylic acid ester copolymer (X).

In one embodiment of the present invention, the degree of branching of the ethylene-carboxylic acid ester copolymer (X) per 1000 carbons is not particularly limited, but is preferably 5 to 30, more preferably 6 to 20. The degree of branching per 1000 carbons can be analyzed, for example, by dissolving an ethylene-carboxylic acid ester copolymer in deuterated orthodichlorobenzene and using the inverse gate decoupling method of ^{13 C-NMR.}

In the above methods (1) and (2), as the solvent for carrying out the saponification reaction with alkali, for example, an ether solvent such as tetrahydrofuran and dioxane; a halogen-containing solvent such as chloroform and dichlorobenzene; and carbon such as methylbutylketone. Hydrocarbon-based solvents such as ketones, n-hexane, cyclohexane, etc. with a number of 6 or more; alcohol-based solvents such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol; aromatics such as benzene, toluene, xylene, ethylbenzene, etc. Examples include group solvents. These solvents can be used alone or in combination of two or more, and when two or more solvents are used, for example, a mixed solvent of a hydrocarbon solvent and an alcohol solvent, or an aromatic solvent and an alcohol solvent. A mixed solvent or the like may be used.

In the above methods (1) and (2), the temperature at which the saponification reaction is carried out with an alkali is 50 ° C. or higher from the viewpoint of its reactivity and the solubility of the ethylene-carboxylic acid ester copolymer (X). Preferably, 60 ° C. or higher is more preferable, 70 ° C. or higher is further preferable, and 80 ° C. or higher is most preferable. The upper limit of the temperature is not particularly limited, but a temperature at which the ethylene-carboxylic acid ester copolymer (X) does not decompose is preferable, for example, 300 ° C. or lower.

In the above methods (1) and (2), known organic acids or inorganic acids such as acetic acid, hydrochloric acid, nitric acid, and sulfuric acid can be used as the acid used for demetallization. As the solvent used for demetallization, the same solvent as in the saponification reaction can be selected.

In the method (2), the neutralizing agent used for neutralization is not particularly limited as long as it is an ionic compound containing the above-mentioned metal ion. Examples of the metal ion include alkali metal ions such as lithium, potassium and sodium, alkaline earth metal ions such as magnesium and calcium, transition metal ions such as zinc, nickel, iron and titanium, and aluminum ions. For example, examples of the neutralizing agent when the metal ion is a sodium cation include sodium hydroxide, sodium acetate, sodium hydrogencarbonate and the like. Further, a polymer such as ionomer containing a sodium carboxylate unit can also be used as a neutralizing agent.

Examples of the method for producing the raw material resin include, in addition to the above method, a method of copolymerizing ethylene, the carboxylic acid and the carboxylic acid ester at high temperature and high pressure, and then neutralizing a part of the carboxylic acid unit. For example, the method for producing a resin in JP-A-59-133217, US Pat. No. 6,518,365, and US Pat. No. 8,939,906 can be referred to.

<Manufacturing of raw material sheet>
The method for producing the raw material sheet of the present invention is not particularly limited, and for example, the raw material resin or the resin composition obtained by adding an additive to the raw material resin as needed is uniformly kneaded, preferably melt-kneaded, and then extruded. It can be obtained by forming a layer by a known film forming method such as a method, a calendar method, a compression molding method, a pressing method, a solution casting method, a melt casting method, or an inflation method. When the raw material sheet is a laminated body, the layer and another layer may be molded by a coextrusion method to obtain a laminated resin sheet. The raw material resin may be kneaded, preferably the additive may be added during melt kneading.

Among the known film-forming methods, a method for producing a resin sheet using a compression molding method or an extrusion method is particularly preferably used. The resin temperature during compression molding or extrusion is preferably 150 ° C. or higher, more preferably 170 ° C. or higher, preferably 250 ° C. or lower, and more preferably 230 ° C. or lower. When the resin temperature is not more than the above upper limit, it is easy to suppress the decomposition and deterioration of the resin. On the contrary, when the resin temperature is equal to or higher than the above lower limit, the moldability of the resin is likely to be improved. Further, for example, when an extruder is used, in order to efficiently remove the volatile substance, it is preferable to remove the volatile substance by reducing the pressure from the vent port of the extruder.

<Irradiation process>
The resin sheet of the present invention can be obtained by a method including a step of irradiating the raw material sheet with an electron beam having an acceleration voltage of 200 to 5000 kV and an irradiation dose of 10 to 500 kGy.

The degree of electron beam cross-linking of the resin sheet can be adjusted by the magnitude of the acceleration voltage and irradiation dose of the electron beam, and as the acceleration voltage and irradiation dose increase, the degree of electron beam cross-linking of the resin sheet tends to increase. On the contrary, as the acceleration voltage and the irradiation dose become smaller, the degree of electron beam cross-linking of the resin sheet tends to become smaller.

The acceleration voltage of the electron beam can be appropriately selected according to the thickness of the resin sheet, and is preferably 500 kV or more, more preferably 1000 kV or more, still more preferably 1500 kV or more, preferably 4500 kV or less, more preferably 3500 kV or less, still more preferably. Is 2500 kV or less. When the acceleration voltage is equal to or higher than the above lower limit, the transparency of the resin sheet is likely to be improved. Further, since it is easy to crosslink to the deep part of the resin sheet, uneven irradiation in the thickness direction is unlikely to occur, and it is easy to suppress the variation in transparency and partial coloring of the resin sheet due to this. On the contrary, when the acceleration voltage is not more than the above upper limit, it is easy to suppress excessive cross-linking, and it is easy to improve the adhesive processability at the time of producing the laminated glass.

The irradiation dose of the electron beam can be appropriately selected according to the amount of the carboxylic acid unit of the raw material resin, and is preferably 15 kGy or more, more preferably 20 kGy or more, preferably 400 kGy or less, more preferably 300 kGy or less, still more preferably 250 kGy. It is as follows. When the irradiation dose of the electron beam is equal to or higher than the above lower limit, the transparency of the resin sheet is likely to be improved. Further, when the irradiation dose of the electron beam is not more than the above upper limit, the adhesive processability of the resin sheet is easily improved and coloring is easily suppressed.

In the production method according to the embodiment of the present invention, when the thickness of the raw material sheet is t (mm), the acceleration voltage is V (kV), and the specific gravity of the raw material sheet is ρ (g / m ³ ).
The following formula (3):
33.4 × V ^5/3 ÷ ρ ≧ t (3)
It is preferable to satisfy. Equation (3) optimizes the thickness range of the raw material sheet with respect to the acceleration voltage V. When Equation (3) is satisfied, it is easy to crosslink to the deep part of the resin sheet, so that irradiation unevenness in the thickness direction is unlikely to occur. It is easy to suppress the variation in transparency and partial coloring of the resin sheet due to the above. The upper limit of the thickness t (mm) of the raw material sheet is preferably less than 3 mm.

In the production method according to the embodiment of the present invention, when the content of the carboxylic acid unit of the raw material sheet is a'(mol%) and the irradiation dose is c (kGy).
The following equations (4) and (5):
2 ≤ a'≤ 9 (4)
-15 × a'+ 115 ≦ c ≦ 500 (5)
It is preferable to satisfy. The formula (5) is an optimized range of the irradiation dose c of the electron beam with respect to the content of the carboxylic acid unit. When the formulas (4) and (5) are satisfied, the degree of cross-linking with respect to the content of the carboxylic acid unit is satisfied. Since it is easy to adjust the (insoluble content) to a suitable range, it is easy to improve the transparency, strength, adhesive processability and independence of the obtained resin sheet in a high temperature environment.

The method of irradiating the electron beam is not particularly limited as long as the raw material sheet can be irradiated with the predetermined electron beam. For example, a resin sheet is placed on the support material, and the predetermined electron beam is applied to the sheet surface by an electron beam irradiator or the like. There is a method of irradiating the electron. The irradiation angle of the electron beam on the sheet surface is not particularly limited, but it is preferable to irradiate the sheet surface from a direction perpendicular to the sheet surface.

The resin sheet of the present invention may be subjected to surface treatment such as corona treatment, plasma treatment, frame treatment, ultraviolet ozone treatment, etc. before or after electron beam irradiation for the purpose of controlling surface energy.

By using such a manufacturing method of the present invention, it is possible to obtain a resin sheet having excellent transparency, strength, independence in a high temperature environment, and adhesive processability.

[Interlayer film for laminated glass and laminated glass]
The present invention includes an interlayer film for laminated glass (also simply referred to as an interlayer film) made of the resin sheet of the present invention. The present invention also includes a laminated glass having two glass plates and an interlayer film for the laminated glass arranged between the two glass plates.

Since the laminated glass of the present invention has an interlayer film for laminated glass made of the resin sheet, it is excellent in transparency, strength, independence in a high temperature environment, and adhesive processability between the interlayer film and the glass plate during manufacturing. ing.

The glass plate laminated with the interlayer film of the present invention includes, for example, inorganic glass such as float plate glass, polished plate glass, template glass, meshed plate glass, and heat ray absorbing plate glass, as well as conventionally known organic glass such as polymethyl methacrylate and polycarbonate. Etc. can be used. These may be either colorless or colored. One of these may be used, or two or more thereof may be used in combination. The thickness of the glass is preferably 100 mm or less.

The laminated glass formed by sandwiching the resin sheet of the present invention between two sheets of glass can be produced by a conventionally known method. For example, a method using a vacuum laminator device, a method using a vacuum bag, a method using a vacuum ring, a method using a nip roll, and the like can be mentioned. Further, there is also a method of temporarily crimping by the above method and then putting it into an autoclave for main bonding.

When a vacuum laminator device is used, for example, ^{under a reduced pressure of 1 × 10 -6} to 1 × 10 ^-1 MPa, a glass plate, an interlayer film, and optionally an adhesive resin layer or the like can be formed at 60 to 200 ° C., particularly 80 to 160 ° C. It will be laminated. A method using a vacuum bag or a vacuum ring is described, for example, in European Patent No. 1235683, where it is laminated at 100-160 ° C. under a pressure of ^{about 2 × 10 -2} to 3 × 10 ^{-2 MPa.} ..

As a manufacturing method using a nip roll, there is a method of degassing with a roll at a temperature equal to or lower than the flow start temperature of the interlayer film and then crimping at a temperature closer to the flow start temperature. Specifically, for example, a method of heating to 30 to 70 ° C. with an infrared heater or the like, degassing with a roll, further heating to 50 to 120 ° C., and then crimping with a roll can be mentioned.

When crimping is performed by using the above method and then charged into an autoclave for further crimping, the operating conditions of the autoclave process are appropriately selected depending on the thickness and composition of the laminated glass, and the pressure is, for example, 0.5 to 1.5 MPa. Underneath, it is preferable to treat at 100 to 160 ° C. for 0.5 to 3 hours.

The laminated glass of the present invention has excellent transparency. For example, the haze (slow cooling haze) after heating the laminated glass of the present invention to 140 ° C. and then slowly cooling to 23 ° C. at a rate of 0.1 ° C./min is preferably 5.0% or less, more preferably. It is 4.5% or less, more preferably 4.0% or less, particularly preferably 3.5% or less, and even more preferably 3.0% or less. When the slow cooling haze is equal to or less than the above upper limit, the transparency of the laminated glass is likely to be improved. The lower limit of the slow cooling haze of the laminated glass is not particularly limited, but is usually 0.01% or more. The slow-cooling haze of the laminated glass is based on JIS K7136: 2000 using a haze meter after heating the laminated glass to 140 ° C. and then slowly cooling it to 23 ° C. at a rate of 0.1 ° C./min. It can be measured, for example, by the method described in Examples.

The laminated glass of the present invention is less colored and is preferably colorless as much as possible. The yellowness (YI) of the laminated glass of the present invention is preferably 2.0 or less, more preferably 1.8 or less, still more preferably 1.5 or less, particularly preferably 1.0 or less, and even more preferably 0. It is 5 or less. The lower limit of the yellowness of the laminated glass of the present invention is not particularly limited, but is usually 0 or more.

It is preferable that the laminated glass of the present invention and the interlayer film have a high adhesive force. For example, the value evaluated by the compression shear strength test described in International Publication No. 1999/058334 is preferably 15 MPa or more, more preferably 20 MPa or more, and most preferably 25 MPa or more. The upper limit is not particularly specified, but is 100 MPa or less.

As described above, the resin sheet of the present invention is useful as an interlayer film for laminated glass. The laminated glass interlayer film is particularly preferable as a laminated glass interlayer film for structural materials because it is excellent in transparency, strength, self-supporting property in a high temperature environment, and adhesive processability during manufacturing. Further, it is suitable not only as an interlayer film for laminated glass for structural materials but also as an interlayer film for laminated glass in various applications such as moving bodies such as automobiles, buildings, and solar cells, but is limited to these applications. is not it.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Analysis of resins used in Examples and Comparative Examples]
Regarding the resins (IO1 to IO9) used as raw materials for the resin sheet, the content of methacrylic acid unit (carboxylic acid unit), methacrylic acid neutralized product unit (carboxylic acid neutralized product unit), and ethylene unit is analyzed as follows. I went like this.

In Examples and Comparative Examples, the resin used as a raw material for the resin sheet was dissolved in a mixed solvent of dehydrated toluene / dehydrated acetic acid (75/25 (mass ratio)), reacted at 100 ° C. for 2 hours, and then acetone /. The methacrylic acid neutralized product was converted into methacrylic acid units by reprecipitation in a mixed solvent of water (80/20 (mass ratio)). The obtained resin was sufficiently washed with water and then dried to obtain a resin.
(1) Next, the components of the polymerization units constituting the obtained resin were analyzed by thermal decomposition GC-MS.
(2) Next, the acid value of the obtained resin was measured according to JIS K0070-1992.
^{(3) Further, 1} H-NMR (400 MHz, manufactured by JEOL Ltd.) of the obtained resin was measured in a mixed solvent of deuterated toluene and deuterated methanol.
(4) In addition, after each of the resins used as the raw material of the resin sheet was pretreated by microwave decomposition with nitric acid, the type and amount of metal ions of the methacrylic acid neutralized product were determined by ICP emission spectrometry (Thermo Fisher Scientific iCAP6500Duo). Identified.
From the above (1), the type and structure of the methacrylic acid unit are identified, and based on the information, from the information of (2) and (3), the ethylene unit / (the total of the methacrylic acid unit and the methacrylic acid neutralized product unit). ) Was calculated. Furthermore, from the information in (4), the ratio of ethylene unit / methacrylic acid unit / methacrylic acid neutralized product unit was calculated.

[Penetration resistance]
A test piece having a length of 60 mm and a width of 60 mm was cut out from the resin sheets obtained in Examples and Comparative Examples, and the measurement temperature was 23 ° C. using a drop weight type impact tester (CEAST9350 manufactured by Instron) in accordance with ASTM D3763. The test was conducted under the conditions of a load of 2 kg and a collision speed of 9 m / sec, and when the test piece was penetrated, it penetrated from the moment when the tip of the striker touched the test piece (sensed the test force) (the test force returned to zero). The penetration energy (J) was calculated from the area of the SS curve up to).

[Storage modulus]
A test piece having a length of 40 mm and a width of 5 mm was cut out from the resin sheets obtained in Examples and Comparative Examples, and stored under the conditions of a measurement temperature of 50 ° C. and a frequency of 1 Hz using a dynamic viscoelasticity measuring device manufactured by UBM Co., Ltd. The elastic modulus (E') was measured. When the storage elastic modulus at the measurement temperature of 50 ° C. is in the range of 50 to 300 MPa, the self-supporting property of the resin sheet (laminated glass interlayer film) in a high temperature environment becomes good.

Similarly, the storage elastic modulus (E') was measured under the conditions of a measurement temperature of 140 ° C. and a frequency of 1 Hz. When the storage elastic modulus at the measurement temperature of 140 ° C. is 0.1 to 2.5 MPa, the adhesive processability becomes good when the laminated glass is produced using the resin sheet (interlayer film for laminated glass).

[Colorability]
The resin sheets obtained in Examples and Comparative Examples were measured using a colorimetric color difference meter "ZE-2000" (trade name) manufactured by Nippon Denshoku Kogyo Co., Ltd. in accordance with JIS Z8722. Based on the obtained values, the yellowness (YI) was calculated according to JIS K7373.

[Toluene / acetic acid insoluble content (insoluble content)]
The resin sheets (0.1 g) obtained in Examples and Comparative Examples were immersed in a mixed solvent (9.9 g) of dehydrated toluene / acetic anhydride (75/25 (mass ratio)) and stirred with a magnetic stirrer. After shaking at 60 ° C. for 5 hours, the mixture was filtered using a nylon filter mesh and separated into solid and liquid. The solid layer containing the swollen material is taken out, vacuum dried using the above vacuum dryer under the conditions of 0.1 kPa and 70 ° C. until the mass change disappears, the mass after drying is measured, and the toluene / acetic acid insoluble content is measured. It was defined as mass. The mass fraction (insoluble content (mass%)) of the toluene / acetic acid insoluble matter represented by the following formula (6) was calculated.
Mass fraction of toluene / acetic acid insoluble = Ma / Mc × 100 (6)
[In the formula, Mc is the mass (g) of the resin sheet, and Ma is the mass (g) of the toluene / acetic acid insoluble matter].

[Roll take-up property]
The resin sheets obtained in Examples and Comparative Examples were subjected to a three-point bending test in accordance with JIS K7117 using Autograph (manufactured by Shimadzu Corporation, AGS-5kNX) and had a deformation rate of 1 mm / min. The case where no defects such as cracks occurred in the test piece when the test piece was deformed to a strain of 10% at a speed was evaluated as A, and the case where defects such as cracks occurred in the test piece was evaluated as B.

[transparency]
The resin sheets obtained in Examples and Comparative Examples were sandwiched between two 2.7 mm thick float glasses, and the inside of the vacuum laminator was depressurized for 1 minute at 100 ° C. using a vacuum laminator (1522N manufactured by Nisshinbo Mechatronics Co., Ltd.). A temporary adhesive was obtained by pressing at 30 kPa for 5 minutes while maintaining the degree of reduced pressure and temperature. The obtained temporary adhesive was put into an autoclave and treated at 140 ° C. and 1.2 MPa for 30 minutes to obtain a laminated glass.

The laminated glass obtained by the above method was heated to 140 ° C. and then slowly cooled to 23 ° C. at a rate of 0.1 ° C./min. The haze of the laminated glass after the slow cooling operation was measured using a haze meter HZ-1 (manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS K7136: 2000.

[Measurement of film thickness]
The thickness of the raw material sheet was measured using a digital microgauge.

[Resin used as a raw material]
The resins (IO1 to IO9) used as raw materials for the resin sheets obtained in Examples and Comparative Examples are methacrylic acid unit or acrylic acid unit (carboxylic acid unit), methacrylic acid neutralized product unit or acrylic acid neutralized product unit. (Carboxylic acid neutralized product unit) and an ionomer having an ethylene unit, and the carboxylic acid species, the content thereof, and the metal species of the neutralized product unit are shown in Table 1.

[Example 1]
50 g of IO1 (“Himilan 1707”, manufactured by Mitsui Dow Polychemical Co., Ltd.) shown in Table 1 is melted by melt-kneading at 200 ° C. and 100 rpm for 3 minutes using a lab plast mill (manufactured by Toyo Seiki Seisakusho Co., Ltd.). Obtained a kneaded product. The obtained melt-kneaded product was ^{compression-molded at a pressure of 50 kgf / cm 2} for 5 minutes under heating at 200 ° C. to obtain a raw material sheet having a thickness of 0.8 mm. The obtained raw material sheet is fixed on a support material installed in a movable cart, and a total is used under the conditions of an acceleration voltage of 2000 kV and a current of 20 mA using an electron beam irradiation device (Dyamitron type electron accelerator manufactured by RDI). The electron beam was irradiated from the direction perpendicular to the sheet surface so that the irradiation dose was 200 kGy. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of the first embodiment satisfies the relational expression of the formulas (1) to (5).

[Example 2]
A resin sheet was obtained in the same manner as in Example 1 except that the irradiation dose of the electron beam was changed to 120 kGy. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of the second embodiment satisfies the relational expression of the formulas (1) to (5).

[Example 3]
A resin sheet was obtained in the same manner as in Example 1 except that IO2 shown in Table 1 was used as a raw material resin and the irradiation dose of the electron beam was changed to 30 kGy. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of Example 3 satisfies the relational expression of the formulas (1) to (5).

[Example 4]
IO2 shown in Table 1 is used as a raw material resin, 0.015 g of 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyldiethoxysilane are added as a silane coupling agent at the time of melt-kneading, and irradiation with an electron beam is performed. A resin sheet was obtained in the same manner as in Example 1 except that the dose was changed to 20 kGy. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of the fourth embodiment satisfies the relational expression of the formulas (1) to (5).

[Example 5]
0.2 g of 2- (2H-benzotriazole-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (manufactured by BASF; trade name TINUVIN234) was added as an ultraviolet absorber during melt-kneading. A resin sheet was obtained in the same manner as in Example 1 except that the irradiation dose of the electron beam was changed to 150 kGy. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of Example 5 satisfies the relational expression of the formulas (1) to (5).

[Example 6]
A resin sheet was obtained in the same manner as in Example 1 except that IO8 shown in Table 1 was used as a raw material resin and the irradiation dose of the electron beam was changed to 60 kGy. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of Example 6 satisfies the relational expression of the formulas (1) to (5).

[Example 7]
A resin sheet was obtained in the same manner as in Example 1 except that IO9 shown in Table 1 was used as a raw material resin and the irradiation dose of the electron beam was changed to 200 kGy. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of Example 7 satisfies the relational expression of the formulas (1) to (5).

[Comparative Example 1]
A resin sheet was obtained in the same manner as in Example 1 except that IO3 (Himilan 1601, manufactured by Mitsui Dow Polychemical Co., Ltd.) shown in Table 1 was used as a raw material resin. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of Comparative Example 1 satisfies the formulas (3) and (5), but does not satisfy the formulas (1), (2) and (4).

[Comparative Example 2]
A resin sheet was obtained in the same manner as in Example 1 except that IO4 shown in Table 1 was used as a raw material resin and the irradiation dose of the electron beam was changed to 30 kGy. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of Comparative Example 2 satisfies the formulas (2) and (5), but does not satisfy the formulas (1) and (4).

[Comparative Example 3]
A resin sheet was obtained in the same manner as in Example 1 except that IO5 shown in Table 1 was used as the raw material resin. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of Comparative Example 3 satisfies the relational expression of the formulas (1) to (5).

[Comparative Example 4]
A resin sheet was obtained in the same manner as in Example 1 except that the irradiation dose of the electron beam was changed to 1000 kGy. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of Comparative Example 4 satisfies the formulas (1) and (4), but does not satisfy the formulas (2) and (5).

[Comparative Example 5]
The same as in Example 1 except that IO6 shown in Table 1 was used as the raw material resin, the thickness of the obtained resin sheet was 3.0 mm, the acceleration voltage of the electron beam was changed to 500 kV, and the irradiation dose was changed to 120 kGy. A resin sheet was obtained by the method. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of Comparative Example 5 satisfies the relational expression of the formulas (1) to (5).

[Comparative Example 6]
IO7 (Himilan 1650, manufactured by Mitsui Dow Polychemical Co., Ltd.) shown in Table 1 is used as a raw material resin, the thickness of the obtained resin sheet is 0.1 mm, the acceleration voltage of the electron beam is 150 kV, and the irradiation dose is 120 kGy. A resin sheet was obtained in the same manner as in Example 1 except that the resin sheet was changed to. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of Comparative Example 6 does not satisfy the formula (2), but satisfies the formulas (1) and (3) to (5).

[Comparative Example 7]
A resin sheet was obtained in the same manner as in Example 1 except that the acceleration voltage of the electron beam was changed to 200 kV and the irradiation dose was changed to 180 kGy. The obtained resin sheet was analyzed and its characteristics were evaluated. The film thickness of the obtained resin sheet was the same as the film thickness of the raw material sheet. The aspect of Comparative Example 6 does not satisfy the formulas (2) and (3), but satisfies the formulas (1), (4) and (5).

Penetration resistance, storage elastic modulus, colorability, toluene / acetic acid insoluble content (insoluble content), roll winding property, and laminated glass of the resin sheets obtained in Examples 1 to 7 and Comparative Examples 1 to 7. Table 2 shows the evaluation results of the transparency of.

As shown in Table 2, the resin sheets obtained in Examples 1 to 7 have a high penetration energy (J), a storage elastic modulus in the range of 50 to 300 MPa at 50 ° C., and a storage elastic modulus at 140 ° C. It was confirmed that the range was 0.1 to 2.5 MPa, the YI was low, the roll take-up property evaluation result was A, and the slow cooling haze of the laminated glass was low. On the other hand, the resin sheets obtained in Comparative Examples 1 to 7 were defective in at least one of the penetration energy (J), the storage elastic modulus at 50 ° C., the storage elastic modulus at 140 ° C., and the slow cooling haze. The result was In Comparative Example 5, YI and roll take-up property were also poor.

Therefore, the resin sheets obtained in Examples 1 to 7 are excellent in transparency, strength, independence in a high temperature environment, adhesive processability at the time of producing laminated glass, and roll winding property, and have low coloring property. I understood it.

Claims (11)

1. Contains 2.0 to 9.0 mol% of carboxylic acid units, 1.0 to 3.0 mol% of carboxylic acid neutralized units, and ethylene units based on all the monomer units constituting the resin. A resin sheet containing a resin, having a thickness of 0.2 mm or more and less than 3 mm, and having an insoluble content of 5 to 90% by mass in a mixed solvent of toluene / acetic acid (mass ratio) = 75/25.
2. The resin sheet according to claim 1, wherein the storage elastic modulus at 50 ° C. is 50 to 300 MPa, and the storage elastic modulus at 140 ° C. is 0.1 to 2.5 MPa.
3. When the content of the carboxylic acid unit of the resin sheet is a (mol%) and the insoluble content is b (mass%),
   The following equations (1) and (2):
   2 ≦ a ≦ 9 (1)
   -7.8 × a + 96 ≦ b ≦ 90 (2)
   The resin sheet according to claim 1 or 2, which satisfies the above conditions.
4. The resin sheet according to any one of claims 1 to 3, which contains at least one selected from the group consisting of an ultraviolet absorber and a silane coupling agent.
5. The resin sheet according to any one of claims 1 to 4, wherein the content of the resin is 95% by mass or more with respect to the mass of the resin sheet.
6. An interlayer film for laminated glass made of the resin sheet according to any one of claims 1 to 5.
7. A laminated glass having two glass plates and an interlayer film for laminated glass according to claim 6, which is arranged between the two glass plates.
8. The laminated glass according to claim 7, wherein the laminated glass has a haze of 5.0% or less after heating to 140 ° C. and then slowly cooling to 23 ° C. at a rate of 0.1 ° C./min.
9. A claim comprising a step of irradiating a raw material sheet containing a resin containing a carboxylic acid unit, a carboxylic acid neutralized product unit, and an ethylene unit with an electron beam having an acceleration voltage of 200 to 5000 kV and an irradiation dose of 10 to 500 kGy. Item 8. The method for producing a resin sheet according to any one of Items 1 to 5.
10. When the thickness of the raw material sheet is t (mm), the acceleration voltage is V (kV), and the specific gravity of the raw material sheet is ρ (g / m ³ ).
    The following formula (3):
    33.4 × V ^5/3 ÷ ρ ≧ t (3)
    9. The method of claim 9.
11. When the content of the carboxylic acid unit of the raw material sheet is a'(mol%) and the irradiation dose is c (kGy),
    The following equations (4) and (5):
    2 ≤ a'≤ 9 (4)
    -15 × a'+ 115 ≦ c ≦ 500 (5)
    The method according to claim 9 or 10, which satisfies the above conditions.