JP5513004B2 - Ethylene vinyl acetate copolymer composition for adhesion to acrylic resin substrate and production method thereof - Google Patents

Description

  The present invention relates to an ethylene vinyl acetate copolymer (EVA) composition used for adhesion of an acrylic resin base material used for an optical filter or the like attached to an image display part such as a plasma display panel (PDP) or a liquid crystal display. In particular, the present invention relates to an EVA composition containing a crosslinking agent and having improved adhesion.

  Conventionally, an ethylene vinyl acetate copolymer (hereinafter abbreviated as EVA) composition is used as an interlayer film for laminated glass and a sealing film for solar cells, and an optical filter used for an image display unit such as a PDP. It is used for adhesion of acrylic resin base materials used in The interlayer film for laminated glass is sandwiched between glass plates and exhibits functions such as penetration resistance and prevention of scattering of broken glass (Patent Documents 1 and 2). As a sealing film for solar cells, it is arrange | positioned at the surface and back surface of a cell for solar cells, and functions, such as ensuring insulation and ensuring mechanical durability, are demonstrated (patent document 3). In addition, when an acrylic resin base material used for an optical filter or the like is bonded, high insulation, durability, weather resistance, and the like are required.

  For these functions, the EVA composition needs to improve adhesiveness, and generally a crosslinking agent such as an organic peroxide is blended, and EVA is crosslinked by heating or the like.

  In the case where a crosslinking agent is blended in the EVA composition, there is a limitation in processing temperature in order to prevent gelation due to heating when the composition is kneaded and formed into a film, and there is a problem in workability. Patent Document 1 discloses a method of adding a plasticizer to an EVA composition in order to improve workability when EVA and a crosslinking agent such as peroxide are mixed. Patent Document 2 discloses a method in which an organic peroxide as a crosslinking agent is dissolved in an organic solvent or the like and applied or immersed in an EVA resin formed in advance.

JP 58-79848 A JP 58-79850 A JP 2008-258255 A

However, in the method of Patent Document 1, when a crosslinking agent is blended in the EVA composition, even if a plasticizer is blended, the compatibility with EVA is low, particularly when a solid crosslinking agent is blended, poor dispersion In some cases, the adhesiveness was lowered. In the method of Patent Document 2, E
Since the cross-linking agent solution is applied after the VA resin is formed, the cross-linking agent does not uniformly penetrate into EVA, and sufficient adhesiveness may not be obtained.

  In the Japanese Patent Application No. 2009-32399 (unpublished), the present inventors have found a method for producing an EVA composition in which the dispersibility of the crosslinking agent is improved and the adhesiveness is improved. However, when the EVA composition obtained by this method is used for an acrylic resin substrate, the acrylic resin is eroded and damage such as deformation of the substrate may occur.

  Accordingly, an object of the present invention is to provide an EVA composition containing a crosslinking agent and having improved adhesiveness, which can be effectively used for an acrylic resin substrate, and a method for producing the same. It is in.

In manufacturing the EVA composition containing EVA and a crosslinking agent in the above-mentioned unpublished patent application, the inventors used a crosslinking agent as a solubility parameter of 14.3 to 19.2 (J / cm ³ ) ^{1 /} It is found that an EVA composition with improved dispersibility of the cross-linking agent and improved adhesion can be produced by preparing a cross-linking agent solution by dissolving or diluting in ² liquid and mixing it with EVA. . Solubility parameter (hereinafter abbreviated as SP value) is a cohesive energy density (CED), ie, the energy of evaporation per unit volume of one molecule to the 1/2 power, and the polarity of the substance per unit volume (Refer to “Practical Plastic Glossary of Terms, Second Edition”, page 565 (Showa 45, Plastic Age Co., Ltd.)). Use a liquid that dissolves or dilutes the cross-linking agent with the SP value described above, dissolves or dilutes the cross-linking agent in this to prepare a cross-linking agent solution, and then mixes the cross-linking agent solution with EVA. Thus, since the cross-linking agent can be uniformly dispersed and mixed in the EVA composition, the cross-linked structure of EVA can be formed uniformly and the adhesiveness can be improved. This is presumably because the compatibility of the crosslinking agent was improved because the SP value of the liquid for dissolving or diluting the crosslinking agent approximated the SP value of EVA.

  Furthermore, the present inventors examined what can be effectively used for the acrylic resin base material in the above production method. As a result, if the SP value of the liquid for dissolving or diluting the cross-linking agent is within a certain range, it is difficult to erode the acrylic resin by the liquid contained in the composition, and even if it is used for a base material containing the acrylic resin, the base material The present inventors have found that no damage such as deformation occurs in the present invention.

That is, the above object is a method for producing an EVA composition for acrylic resin substrate adhesion, in which a crosslinking agent is dissolved or diluted in a liquid having a solubility parameter of 16.5 to 18.4 (J / cm ³ ) ^1/2. And preparing a cross-linking agent solution, and mixing the cross-linking agent solution into EVA.

Preferred embodiments of the production method according to the present invention are as follows.
(1) The crosslinking agent is a solid crosslinking agent.
(2) The liquid is a plasticizer.
(3) The plasticizer is an ester compound of a saturated or unsaturated polyvalent carboxylic acid having 2 to 20 carbon atoms or an aromatic polyvalent carboxylic acid having 8 to 20 carbon atoms.
(4) The ester compound of the polyvalent carboxylic acid is an ester compound of the polyvalent carboxylic acid and an alcohol having 2 to 14 carbon atoms.
(5) The ester compound of the polyvalent carboxylic acid is at least one selected from the group consisting of an adipic acid ester compound, a dodecanedioic acid ester compound, and a trimellitic acid ester compound.
(6) The plasticizer is a phosphorus-containing compound.
(7) The phosphorus-containing compound is a phosphite compound.
(8) The phosphite compound is represented by the following formula (I):
P (OR ¹ ) ₃ (I)
(In the formula, three R ^{1 s} may be the same or different and each represents a linear or branched alkyl group having 1 to 20 carbon atoms, an aryl group, or an aralkyl group). Phosphite compound.
(9) The crosslinking agent is an organic peroxide.

Moreover, the objective of this invention is EVA composition for acrylic resin base-material adhesion | attachment containing EVA and a crosslinking agent, Comprising: The said composition is further solubility parameter 16.5-18.4 (J / cm < ³ >). It is also achieved by a composition characterized in that it contains ^1/2 liquid. This EVA composition includes the EVA composition for bonding an acrylic resin substrate obtained by the production method of the present invention.

Preferred embodiments of the EVA composition according to the present invention are as follows.
(1) The cross-linking agent is previously dissolved or diluted in the liquid and added to EVA.
(2) The liquid is an ester compound of a saturated or unsaturated polyvalent carboxylic acid having 2 to 20 carbon atoms or an aromatic polyvalent carboxylic acid having 8 to 20 carbon atoms and an alcohol having 2 to 14 carbon atoms. It is.
(3) The ester compound is at least one selected from the group consisting of an adipic acid ester compound, a dodecanedioic acid ester compound, and a trimellitic acid ester compound.
(4) The liquid is represented by the following formula (I):
P (OR ¹ ) ₃ (I)
(In the formula, three R ^{1 s} may be the same or different and each represents a linear or branched alkyl group having 1 to 20 carbon atoms, an aryl group, or an aralkyl group). Phosphite compound.

  ADVANTAGE OF THE INVENTION According to this invention, the EVA composition for acrylic resin base-material adhesion | attachment which improved adhesiveness can be provided. Therefore, by using the EVA composition of the present invention for adhesion of an acrylic resin base material used for an optical filter or the like, the optical filter or the like can be insulated, durable, and weather-resistant without causing damage such as deformation. Etc. can be improved.

It is a schematic sectional drawing for demonstrating the 180 degree peel test method which is an evaluation method of adhesive force.

Below, the manufacturing method of the EVA composition for acrylic resin base-material adhesion | attachment of this invention is demonstrated in detail. In the method for producing an EVA composition of the present invention, at least EVA, a crosslinking agent, and a liquid that can dissolve or dilute the crosslinking agent (hereinafter referred to as “diluent”) have an SP value of 16.5 to 18.4. (J / cm ³ ) ^1/2 , preferably 17.0-18.0 (J / cm ³ ) ^1/2 , more preferably 17.0-17.5 (J / cm ³ ) ^1/2 liquid Is used. And the manufacturing method is
(1) A step of preparing a crosslinking agent solution by dissolving or diluting the crosslinking agent in a diluent,
(2) mixing the cross-linking agent solution with EVA,
including. Since the SP value of EVA used in the present invention is about 17 to 18 (J / cm ³ ) ^1/2 , the crosslinking agent is dissolved or diluted with a diluent having an SP value in the above range in step (1). Thus, in the step (2), it is considered that the crosslinking agent solution is extremely easy to disperse and mix in EVA. Thereby, the adhesiveness of the EVA composition can be improved. Furthermore, if the diluent has an SP value in the above range, the acrylic resin can be hardly eroded.

Conventionally, when the crosslinking agent is mixed with EVA, the mixing method is not particularly studied, and even when pre-dissolved or diluted, the SP value of the diluent is not conscious and is dissolved in an organic solvent such as toluene. It was. In the above-mentioned unpublished patent application, the present inventors paid attention to the SP value of the diluent as described above, and used a diluent having an SP value of 14.3 to 19.2 (J / cm ³ ) ^1/2. It has been found that by dissolving or diluting the cross-linking agent in advance, the compatibility of the cross-linking agent with EVA is improved and the adhesion of the EVA composition is improved. In the present invention, it was found that by further limiting the SP value to the above range, the acrylic resin can be made into a diluent that hardly erodes.

  Therefore, when the EVA composition obtained by the production method of the present invention is used for adhesion of an acrylic resin substrate, it can be strongly bonded without causing damage such as deformation of the substrate. The SP value is calculated according to the following formula (numerical formula I) (see “Practical Plastic Glossary, Second Edition”, page 565 (Showa 45, Plastic Age Co., Ltd.)).

(Diluent)
The diluent used in the present invention is not particularly limited as long as it can dissolve or dilute the crosslinking agent and is a liquid having the above SP value. In particular, it is preferable to use a plasticizer having high compatibility with the resin. The plasticizer is not particularly limited, but generally, polyvalent carboxylic acid ester compounds, polyvalent carboxylic acid metal salts, phosphorus-containing compounds such as phosphites and phosphoric acid esters, polyhydric alcohol ester compounds, etc. are used. it can. In particular, a polyvalent carboxylic acid ester compound or a phosphorus-containing compound is preferable.

  The polycarboxylic acid ester compound is a saturated or unsaturated polyvalent carboxylic acid having 2 to 20 carbon atoms, preferably 4 to 16, more preferably 6 to 12 carbon atoms, or 8 to 20 carbon atoms, preferably 9 to 16 carbon atoms. An aromatic polycarboxylic acid ester compound is preferred. Furthermore, the ester compound is preferably an ester compound of the polyvalent carboxylic acid and an alcohol having 2 to 14, preferably 4 to 12, more preferably 6 to 10 carbon atoms. Examples thereof include adipic acid ditridecyl, adipic acid diisodecyl, adipic acid n-octyl-n-decyl ester, adipic acid methyl diglycol butyl diglycol ester, adipic acid benzyl methyl diglycol ester, Dodecanedioic acid ester compounds such as 2-ethylhexyl, azelaic acid ester compounds such as di-2-ethylhexyl azelate, sebacic acid ester compounds such as dibutyl sebacate and di-2-ethylhexyl sebacate, and fumarate such as dioctyl fumarate Examples include acid ester compounds, trimellitate ester compounds such as trimellitate tri-n-octyl, trimellitate tributyl, trimellitate trihexyl, and phthalate compounds such as diethyl phthalate. Door can be. In particular, adipic acid ester compounds (particularly ditridecyl adipate, diisodecyl adipate, n-octyl-n-decyl adipic acid), dodecanedioic acid ester compounds (particularly di-2-ethylhexyl dodecanedioic acid, didecanedioic acid dioctyl). n-octyl) and trimellitic acid ester compounds (particularly trimellitate tri-n-octyl, trimellitate trihexyl) are preferred.

Moreover, as a phosphorus containing compound, a phosphite compound is preferable. The phosphite compound is a compound in which three hydrocarbon groups are bonded to a phosphorus atom via an oxygen atom. Preferred phosphite compounds include those represented by the following formula (I)
P (OR ¹ ) ₃ (I)
(Wherein, R ¹ is a hydrocarbon group having 1 to 20 carbon atoms).

Three R < ¹ > in the said formula (I) may be same or different, and is a C1-C20 hydrocarbon group. Specifically, an alkyl group, an aryl group, and an aralkyl group are preferable.

  Examples of the alkyl group include linear or branched alkyl groups such as methyl group, ethyl group, n-propyl group, iso-propyl group, tert-butyl group, iso-butyl group, n-butyl group, sec- Butyl group, hexyl group, n-octyl group, iso-octyl, n-decyl group, iso-decyl group, n-dodecyl group, iso-dodecyl group, n-tridecyl group, iso-tridecyl group, n-tetradecyl group, Examples include an iso-tetradecyl group, an n-hexadecyl group, an iso-hexadecyl group, a stearyl group, and a nonadecyl group.

  As the aryl group, phenyl group, 4-propylphenyl group, 4-pentylphenyl group, 4-octylphenyl group, 4-methoxyphenyl group, 4-propoxyphenyl group, 4-pentyloxyphenyl group, 4-octyloxyphenyl Group, 4-butoxymethylphenyl group, 4-octyloxyethylphenyl group, 4-butoxyethoxyphenyl group, 4-octyloxyethoxyphenyl group, 4-butoxybutoxyphenyl group and the like.

  Examples of the aralkyl group include benzyl group, phenethyl group, phenylpropyl group, phenylbutyl group, and phenylhexyl group.

  Specific examples of the phosphite compounds include alkyl phosphites such as trisisodecyl phosphite and trilauryl phosphite, aryl phosphites such as triphenyl (nonylphenyl) phosphite, and diphenylisooctyl phosphite. , Diphenylisodecyl phosphite, diisodecylphenyl phosphite, diisooctyloctylphenyl phosphite, phenylneopentyl glycol phosphite, or 2,4,6-tri-t-butylphenyl- (2-butyl-2-ethyl- And alkyl-aryl phosphites such as 1,3-propanediol) phosphite. In particular, triisodecyl phosphite and trinonylphenyl phosphite are preferable.

  In the present invention, the diluent may be a single compound or a combination of two or more. The amount of the diluent used is preferably in the range of 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and particularly preferably 0.5 to 2.5 parts by mass with respect to 100 parts by mass of the ethylene vinyl acetate copolymer. Part by mass is preferred.

(Crosslinking agent)
The crosslinking agent used in the present invention is not particularly limited as long as it can form an EVA crosslinked structure, and may be a solid crosslinking agent or a liquid crosslinking agent. A solid cross-linking agent capable of obtaining a diluent effect is preferred. Preferably, an organic peroxide that decomposes at a temperature of 100 ° C. or higher to generate radicals can be used as the cross-linking agent. The organic peroxide is generally selected in consideration of the film formation temperature, the adjustment conditions of the composition, the curing temperature, the heat resistance of the adherend, and the storage stability. In particular, the one having a decomposition temperature of 70 ° C. or more with a half-life of 10 hours is preferable.

As the organic peroxide, from the viewpoint of the processing temperature and storage stability of the resin, for example,
A compound having a bifunctional peroxymonocarbonate structure;
1,4-bis (tert-butylperoxycarbonyloxy) hexane, 1,4-bis (tert-amylperoxycarbonyloxy) hexane, 1,4-bis (tert-hexylperoxycarbonyloxy) hexane, 1,4-bis (tert-octyl) Peroxycarbonyloxy) hexane, 1,5-bis (tert-butylperoxycarbonyloxy) hexane, 1,5-bis (tert-amylperoxycarbonyloxy) hexane, 1,5-bis (tert-hexylperoxycarbonyloxy) hexane, 1, 5-bis (tert-octylperoxycarbonyloxy) hexane, 1,6-bis (tert-butylperoxycarbonyloxy) hexane, 1,6-bis (tert-amylperoxycarbonyloxy) hexane, 1,6-bis (tert-hexylperoxycarbonyl) Bonyloxy) hexane, 1,6-bis (tert-octylperoxycarbonyloxy) hexane, oxybisethylenebis (tert-butylperoxycarbonate), oxybisethylenebis (tert-amylperoxycarbonate), oxybisethylenebis (tert-hexyl) Peroxycarbonate), oxybisethylenebis (tert-octylperoxycarbonate), 2,2-dimethyl-1,3-bis (tert-butylperoxycarbonyloxy) propane, 2,2-dimethyl-1,3-bis (tert-amylperoxycarbonyloxy) Propane, 2,2-dimethyl-1,3-bis (t-hexylperoxycarbonyloxy) propane, 2,2-dimethyl-1,3-bis (t-octylperoxycarbonyloxy) propane, etc.
Benzoyl peroxide curing agent;
Benzoyl peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, p-chlorobenzoyl peroxide, m-toluoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butylperoxybenzoate, etc. ,
Other;
tert-butylperoxy-2-ethylhexyl monocarbonate, 1,1-bis (tert-hexylperoxy) -3,3,5-trimethylcyclohexane, tert-hexylperoxypivalate, tert-butylperoxypivalate, 3,5,5-trimethylhexanoyl peroxide, di-n-octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, Succinic acid peroxide, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, tert-hexylper Oxy-2-ethylhexa 4-methylbenzoyl peroxide, tert-butylperoxy-2-ethylhexanoate, m-toluoyl + benzoyl peroxide, benzoyl peroxide, 1,1-bis (tert-butylperoxy) -2-methyl Cyclohexanate, 1,1-bis (tert-hexylperoxy) -3,3,5-trimethylcyclohexanate, 1,1-bis (tert-hexylperoxy) cyclohexanate, 1,1-bis ( tert-butylperoxy) cyclohexanate, 2,2-bis (4,4-di-tert-butylperoxycyclohexyl) propane, 1,1-bis (tert-butylperoxy) cyclododecane, tert-hexylper Oxyisopropyl monocarbonate, tert-butyl -Oxymaleic acid, tert-butylperoxy-3,3,5-trimethylhexanoate, tert-butylperoxylaurate, 2,5-dimethyl-2,5-di (methylbenzoylperoxy) hexane, Examples thereof include tert-butylperoxyisopropyl monocarbonate, tert-hexylperoxybenzoate, 2,5-di-methyl-2,5-di (benzoylperoxy) hexane, and the like.

  These crosslinking agents may be used alone or in combination of two or more. As the crosslinking agent, in particular, 1,6-bis (tert-butylperoxycarbonyloxy) hexane, tert-butylperoxy-2-ethylhexyl monocarbonate, 1,1-bis (tert-hexylperoxy) -3,3,5 -Preferred is trimethylcyclohexane. If it is this organic peroxide, the crosslinking density of EVA can be improved.

  In this invention, the usage-amount of a crosslinking agent is 0.05-5 mass parts with respect to EVA 100 mass parts, More preferably, it is 0.1-3 mass parts, Especially 0.5-2.5 mass parts. is there.

  In the step (1), the crosslinking agent can be dissolved or diluted in a diluent by a known method using a mixer, a blender or the like. For example, a diluent is put in a dissolution tank, a crosslinking agent is added while stirring with a mixer, and the crosslinking agent solution is prepared by sufficiently stirring.

(Ethylene vinyl acetate copolymer)
There is no restriction | limiting in particular in the ethylene vinyl acetate polymer (EVA) used for this invention, According to the use of an EVA composition, it can select. The content of vinyl acetate in EVA is preferably 20 to 35 parts by mass, and particularly preferably 20 to 25 parts by mass with respect to 100 parts by mass of the EVA. The lower the content of EVA in vinyl acetate units, the harder the EVA composition. On the other hand, if the content of vinyl acetate is less than 20 parts by mass, the transparency of the EVA composition may decrease. Moreover, when it exceeds 35 mass parts, when a resin layer is formed with an EVA composition, hardness may become inadequate.

  In the step (2), the crosslinking agent solution prepared in the step (1) can be mixed with EVA by a known method using a super mixer (high speed fluid mixer), a roll mill, or the like. The mixing temperature is preferably 40 to 90 ° C, particularly preferably 50 to 80 ° C.

(Other)
In the production method of the present invention, in the step (2), in addition to the above-mentioned components, a crosslinking agent, an adhesion improver, a plasticizer other than the diluent may be added as necessary.

  The crosslinking aid can improve the gel fraction of EVA and improve the adhesion and durability of the EVA composition. Examples of the crosslinking aid (compound having a radical polymerizable group as a functional group) include trifunctional crosslinking aids such as triallyl cyanurate and triallyl isocyanurate, and (meth) acrylic esters (eg, NK ester). And monofunctional or bifunctional crosslinking aids. Of these, triallyl cyanurate and triallyl isocyanurate are preferable, and triallyl isocyanurate is particularly preferable.

  These crosslinking assistants are generally used in an amount of 10 parts by mass or less, preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the ethylene vinyl acetate copolymer.

  As the adhesion improver, a silane coupling agent can be used. Examples of silane coupling agents include γ-chloropropylmethoxysilane, vinylethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxy. Silane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β Mention may be made of-(aminoethyl) -γ-aminopropyltrimethoxysilane. These silane coupling agents may be used alone or in combination of two or more. Moreover, it is preferable that content of the said adhesive improvement agent is 5 mass parts or less with respect to 100 mass parts of ethylene vinyl acetate copolymers.

  As another plasticizer, in addition to the above plasticizer, for example, a glycerin plasticizer such as glycerin monoacetomonolaurate, a polyalkylene glycol plasticizer such as polyethylene glycol, an epoxy plasticizer such as epoxy triglyceride, Examples thereof include benzoic acid esters of aliphatic polyols such as neopentyl glycol dibenzoate and diethylene glycol dibenzoate, polyacrylic acid esters, silicone oils and paraffins.

  In addition, the production method of the present invention can improve the physical properties of the optical filter (optical properties such as mechanical strength, adhesiveness, transparency, heat resistance, light resistance, crosslinking speed, etc.) depending on the use of the EVA composition. Alternatively, for adjustment, as necessary, it is produced by adding various additives such as an acryloxy group-containing compound, a methacryloxy group-containing compound, an epoxy group-containing compound, an ultraviolet absorber, a light stabilizer, and / or an anti-aging agent. May be.

The EVA composition of the present invention is an EVA composition for adhesion to an acrylic resin base material, which includes EVA and a crosslinking agent, and the composition further has a solubility parameter of 16.5 to 18.4 (J / cm ³ ). A composition comprising ^1/2 liquid (diluent). In the EVA composition of the present invention, in order to further improve the adhesiveness, it is preferable that the cross-linking agent is previously dissolved or diluted in a diluent and added to the EVA composition.

  The EVA composition of the present invention includes the EVA composition for bonding an acrylic resin substrate obtained by the above-described production method of the present invention. Therefore, the preferable kind etc. of the diluent described as a preferable aspect which concerns on the manufacturing method of the EVA composition mentioned above are also a preferable aspect also about the EVA composition of this invention.

  Since the EVA composition of the present invention has improved adhesion and erosion with respect to the acrylic resin is suppressed, it can be advantageously used for adhesion of a substrate containing the acrylic resin. The acrylic resin is generally a polymer of acrylic acid ester or methacrylic acid ester. For example, homopolymers of alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate and hexyl acrylate, and alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate and hexyl methacrylate And copolymers. In the present invention, the type of acrylic resin is not particularly limited, but homopolymers and copolymers such as methyl methacrylate, ethyl methacrylate, or butyl methacrylate are preferred.

  The acrylic resin base material to be bonded using the EVA composition of the present invention may be a base material mainly containing an acrylic resin, and a transparent acrylic glass or acrylic film formed from an acrylic resin, and an acrylic resin are applied. A base material having an acrylic resin layer formed by processing may be used. Therefore, the EVA composition of the present invention can be used, for example, by adhering a PET film on an acrylic resin layer of an optical filter to be attached to an image display unit such as a PDP or a liquid crystal display, or by attaching an acrylic film to a glass plate, It can be effectively used as an intermediate film of laminated glass using glass.

  When using the EVA composition of the present invention, for example, the EVA composition produced as described above is heated and rolled by ordinary extrusion molding or calendar molding (calendering) or the like to form a film by a method of obtaining a sheet material. Can be used. Also, the EVA composition is dissolved in a solvent, and this solution is coated on a suitable support with a suitable coating machine (coater) and dried to form a coating film to obtain a sheet-like material for use. You can also. In addition, it is preferable that the heating temperature at the time of film formation shall be 40-90 degreeC, especially 50-80 degreeC.

  When adhering an acrylic resin base material used for an optical filter or the like, for example, an EVA composition film or sheet molded as described above is sandwiched and laminated between two base materials to be adhered, and the lamination is performed. By degassing the body and pressing it under heating (high temperature laminating step), the EVA contained in the intermediate film is crosslinked and cured, and the layers are joined and integrated. The high temperature laminating step is generally performed by heat treatment at 100 to 150 ° C., particularly around 130 ° C., for 10 to 120 minutes, preferably 10 to 60 minutes. Crosslinking and curing may be performed after pre-press bonding at a temperature of, for example, 80 to 120 ° C. The heat treatment is particularly preferably, for example, at 130 ° C. for 10 to 30 minutes (atmospheric temperature). Moreover, it is preferable to perform the said heat processing, applying the press pressure of 0-800 KPa to a laminated body. Although cooling of the laminated body after crosslinking is generally performed at room temperature, in particular, the faster the cooling, the better.

  Since the laminated body bonded in this way uses the EVA composition of the present invention, the adhesion is improved without causing damage such as deformation of the acrylic resin substrate, and the insulation and durability are improved. Excellent in weather resistance.

    The present invention will be described below with reference to examples.

(Examples 1-4, Comparative Examples 1-3)
In the formulations of Examples 1 to 4 and Comparative Examples 1 to 3 shown in Table 1, a crosslinking agent was dissolved in a diluent to prepare a crosslinking agent solution. Subsequently, EVA, the crosslinking assistant, the silane coupling agent, and the previously prepared crosslinking agent solution were supplied to a supermixer with each formulation shown in Table 1, and kneaded at 60 ° C. to prepare an EVA composition. These EVA compositions were calendered at 80 ° C., allowed to cool, and then an EVA resin film (thickness 0.4 mm) was produced.
(Evaluation method)
(1) Evaluation of erodibility of each plasticizer to acrylic film The plasticizer used in each of the above Examples and Comparative Examples was dropped on an acrylic resin film (polymethyl methacrylate resin (PMMA) film) of an optical filter, and 85 It was heated visually at 30 ° C. for 30 minutes to visually check whether the acrylic resin film was dissolved. In the case where dissolution of the acrylic resin film was not recognized, it was marked as ◯.
(2) Evaluation of adhesiveness The adhesiveness of each of the EVA resin films prepared above to the RET film was evaluated by a 180 ° peel test (JIS K 6584, 1994). Specifically, the 180 ° peel test was performed as shown in FIG. 1 according to the following procedure.

  The glass substrate 21, each of the EVA resin films 23 and the PET film (thickness 0.05 mm, width 10 cm) 22 are laminated in this order, and the obtained laminate is vacuum deaerated with a vacuum laminator at a temperature of 90 ° C. After pre-pressing, it was further placed in an oven and subjected to pressure heat treatment for 30 minutes at a temperature of 110 ° C. Next, the laminate is allowed to stand for 24 hours under an atmosphere of 23 ° C. and 50% RH, and then a part between the EVA resin film 23 and the PET film 22 is peeled off, and the PET film 22 is folded back 180 ° and pulled. Using a testing machine (manufactured by Shimadzu Corp., Autograph), the peeling force (PET adhesive force) [N / cm] at a pulling speed of 100 mm / min was measured. Adhesiveness evaluated that 10 N / cm or more was favorable.

(Evaluation results)
Table 1 shows the results of the above evaluations. In Examples 1 to 4, when a plasticizer having an SP value of 17.2 to 18.2 (J / cm ³ ) ^1/2 was used as a diluent, it was shown that there was no erosion with respect to the acrylic resin. Moreover, PET adhesive force was 11.8-12.8 N / cm and was favorable.

In contrast, Comparative Example 1 using a plasticizer with an SP value of 16.4 (J / cm ³ ) ^1/2 as a diluent, comparison using a plasticizer with 18.6 (J / cm ³ ) ^1/2 Example 2 had good adhesive strength but was erodible to acrylic resin. Moreover, although the comparative example 3 using the plasticizer of SP value 20.5 (J / cm < ³ >) ^<1/2 > used the same crosslinking agent as an Example, PET adhesive force is 2.0 N / cm. In addition, it was erosive to acrylic resins.

As described above, when an EVA composition is produced, an acrylic resin is obtained by using a liquid having an SP value of 16.5 to 18.4 (J / cm ³ ) ^1/2 as a diluent for a solid crosslinking agent. It has been found that the adhesion of the EVA composition can be improved without erosion.

  In addition, this invention is not limited to the structure and Example of said embodiment, A various deformation | transformation is possible within the range of the summary of invention.

  By using the EVA composition of the present invention for adhesion of a substrate containing an acrylic resin related to an optical filter or the like, an optical filter or the like having improved insulation, durability, and weather resistance can be produced.

21 Glass substrate 22 PET film 23 EVA resin film

Claims (15)

A method for producing an ethylene vinyl acetate copolymer composition for adhesion to an acrylic resin substrate,
Preparing a cross-linking agent solution by dissolving or diluting the cross-linking agent in a liquid having a solubility parameter of 16.5 to 18.4 (J / cm ³ ) ^1/2 ;
Mixing the crosslinker solution into an ethylene vinyl acetate copolymer;
Manufacturing method.   The production method according to claim 1, wherein the crosslinking agent is a solid crosslinking agent.   The production method according to claim 1, wherein the liquid is a plasticizer.   The production method according to claim 3, wherein the plasticizer is an ester compound of a saturated or unsaturated polyvalent carboxylic acid having 2 to 20 carbon atoms or an aromatic polyvalent carboxylic acid having 8 to 20 carbon atoms.   The manufacturing method according to claim 4, wherein the ester compound of the polyvalent carboxylic acid is an ester compound of the polyvalent carboxylic acid and an alcohol having 2 to 14 carbon atoms.   The production method according to claim 4 or 5, wherein the ester compound of the polyvalent carboxylic acid is at least one selected from the group consisting of an adipic acid ester compound, a dodecanedioic acid ester compound, and a trimellitic acid ester compound.   The manufacturing method according to claim 3, wherein the plasticizer is a phosphorus-containing compound.   The production method according to claim 7, wherein the phosphorus-containing compound is a phosphite compound. The phosphite compound has the following formula (I):
P (OR ¹ ) ₃ (I)
(In the formula, three R ^{1 s} may be the same or different and each represents a linear or branched alkyl group having 1 to 20 carbon atoms, an aryl group, or an aralkyl group). The production method according to claim 8, which is a phosphite compound to be produced.   The production method according to claim 1, wherein the crosslinking agent is an organic peroxide. An ethylene vinyl acetate copolymer composition for adhesion to an acrylic resin substrate, comprising an ethylene vinyl acetate copolymer and a crosslinking agent,
The composition further comprises a liquid having a solubility parameter of 16.5 to 18.4 (J / cm ³ ) ^1/2 .   The composition according to claim 11, wherein the crosslinking agent is dissolved or diluted in the liquid and added to the ethylene-vinyl acetate copolymer in advance.   The liquid is an ester compound of a saturated or unsaturated polyvalent carboxylic acid having 2 to 20 carbon atoms or an aromatic polyvalent carboxylic acid having 8 to 20 carbon atoms and an alcohol having 2 to 14 carbon atoms. Item 13. The composition according to Item 11 or 12.   The composition according to claim 13, wherein the ester compound is at least one selected from the group consisting of an adipic acid ester compound, a dodecanedioic acid ester compound, and a trimellitic acid ester compound. The liquid is
The following formula (I):
P (OR ¹ ) ₃ (I)
(In the formula, three R ^{1 s} may be the same or different and each represents a linear or branched alkyl group having 1 to 20 carbon atoms, an aryl group, or an aralkyl group). The composition according to claim 11 or 12, which is a phosphite compound to be produced.

Images