JPH10189933A - Plastic lid material for solid-state image sensor and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic lid material for a solid-state image sensor, having low specific gravity and superior in heat resistance and mechanical characteristic, as well as moldability, transparency, bonding strength, dimensional stability and solvent resistance, and a production method thereof. SOLUTION: A plastic lid material for solid-state image sensor is composed of an acryl-based crosslinked copolymer, produced through urethane reaction and radical polymerization reaction of following components (A), (B) and (C). Component (A): (meta) acrylate-based monomer, having second class hydroxy group, Compound (B): at least one kind of diisocyanate compound, selected from among dicyclohexyl methane-4,4'-diisocyanate, isophorone diisocyanate and 1,3-bis(isocyanate methyl) cyclohexane. Compound (C): a monomer radical copolymerizable with the component (A).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic lid material for a solid-state imaging device package made of an acrylic cross-linked copolymer.

[0002]

2. Description of the Related Art Heretofore, a glass material has been used as a lid material (window material) for sealing a CCD or other solid-state image sensor. However, the glass material has a large specific gravity and is brittle against impact. Further, when manufacturing a lid material made of glass, the glass material may be damaged when handling the glass material or when performing a cutting process, a high yield cannot be obtained, and chipping is likely to occur in the cutting process. Therefore, post-processing is required, and these are factors that increase the manufacturing cost. Further, it is necessary to use a special glass material in order to prevent the device memory from malfunctioning due to radiation such as α-rays. Therefore, there is a strong demand for the development of a plastic lid material having a low specific gravity, high strength, easy molding, and excellent dimensional stability and durability.

[0003]

SUMMARY OF THE INVENTION The present invention has been made based on the above circumstances, and the first aspect of the present invention has been made.
The purpose is to have a low specific gravity, excellent moldability, transparency, adhesive toughness, dimensional stability, solvent resistance, and heat resistance.
An object of the present invention is to provide a plastic lid material for a solid-state imaging device package having excellent mechanical properties. Second embodiment of the present invention
It is an object of the present invention to provide a method capable of advantageously producing the above-mentioned plastic lid material for a solid-state imaging device package having an optical low-pass filter function.

[0004]

According to the present invention, there is provided a plastic lid material for a solid-state image pickup device package, comprising the following components (A), (B) and (C): It is characterized by comprising an acrylic cross-linked copolymer obtained by reacting. Further, the plastic lid material for a solid-state imaging device package of the present invention comprises a (meth) acrylate compound having a urethane bond obtained by a urethanization reaction of the following component (A) and the following component (B): It is characterized by comprising an acrylic crosslinked copolymer obtained by subjecting component (C) to a radical polymerization reaction.

Component (A): (meth) having a secondary hydroxyl group
Acrylic ester monomers. Component (B): dicyclohexylmethane-4,4′-diisocyanate, isophorone diisocyanate and 1,
At least one diisocyanate compound selected from 3-bis (isocyanatomethyl) cyclohexane. Component (C): a monomer capable of being radically copolymerized with component (A).

In the plastic lid material for a solid-state image sensor package of the present invention, it is preferable to use a (meth) acrylate compound having a glycidyl group as a part or all of the component (C).

Further, in the plastic lid material for a solid-state image pickup device package of the present invention, dicyclohexylmethane-4,
It is preferable to use 4'-diisocyanate. Further, a represents the number of moles of the hydroxyl group derived from the (meth) acrylate monomer having a secondary hydroxyl group, b represents the number of moles of the isocyanate group derived from dicyclohexylmethane-4,4′-diisocyanate, and isophorone diisocyanate. And / or when the number of moles of isocyanate groups derived from 1,3-bis (isocyanatomethyl) cyclohexane is c, the following conditions (1) and (2)
Is preferably satisfied. Condition (1) 0.8 <(b + c) / a <1.2. Condition (2): 0 ≦ c / (b + c) <0.85.

In the plastic lid material for a solid-state image pickup device package of the present invention, a diffraction grating having an optical low-pass filter function may be formed on the surface, or a diffraction grating having an optical low-pass filter function on the surface. The layers may be stacked. Further, in the plastic lid material for a solid-state imaging device package of the present invention, an optical multilayer film for selectively reducing transmission or reflection of light in a specific wavelength range may be formed on a surface.

In a method of manufacturing a plastic lid material for a solid-state image pickup device package according to the present invention, at least one mold plate is provided with a pair of mold plates each having a negative pattern of a diffraction grating formed on one surface thereof. To form a cavity, and a (meth) acrylate compound having a urethane bond obtained by a urethanization reaction between the component (A) and the component (B) is formed in the cavity. And a step of obtaining a molded article of an acrylic cross-linked copolymer by copolymerizing the above component (C).

In the present specification, “primary hydroxyl group” means
A hydroxyl group attached to a primary carbon atom. here,
"Primary carbon atom" refers to a carbon atom that is bonded to only one other carbon atom. In addition, “secondary hydroxyl group”
A hydroxyl group attached to a secondary carbon atom. here,
"Secondary carbon atom" refers to a carbon atom that is bonded to two other carbon atoms. Further, “tertiary hydroxyl group” refers to a hydroxyl group bonded to a tertiary carbon atom. Here, the “tertiary carbon atom” refers to a carbon atom bonded to three other carbon atoms.

In this specification, “(meth) acrylic acid” means “acrylic acid” or “methacrylic acid”, and “(meth) acrylate” means “acrylate” or “methacrylate”. .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The plastic lid material for a solid-state imaging device package according to the present invention comprises the component (A) composed of a specific (meth) acrylate monomer, the component (B) composed of a specific diisocyanate compound, and the component (A). It comprises an acrylic cross-linked copolymer obtained by subjecting the component and the component (C) made of a radical copolymerizable monomer to a urethanization reaction and a radical polymerization reaction.

<Component (A)> The specific (meth) acrylate monomer used as the component (A) has a secondary hydroxyl group.
By using such a specific (meth) acrylate monomer, a crosslinked copolymer having high heat resistance and high transparency can be obtained. Specific examples of (meth) acrylate monomers having a secondary hydroxyl group include 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 2-hydroxy-1,3-
Di (meth) acryloxypropane, 2-methacryloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-acryloxypropyl methacrylate, 3
-Chloro-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth)
Acrylate and the like. These compounds can be used alone or in combination of two or more.

When a (meth) acrylate monomer having a primary hydroxyl group such as 2-hydroxyethyl methacrylate is used as a (meth) acrylate monomer for obtaining a crosslinked copolymer, the crosslinked copolymer having high heat resistance is used. No coalescence is obtained, and depending on the type of the component (B) or the component (C) described later, the urethanization reaction or the radical polymerization reaction becomes cloudy, so that a transparent crosslinked copolymer cannot be obtained. . On the other hand, when a monomer having a tertiary hydroxyl group is used as the (meth) acrylic ester monomer, the urethanization reaction between the tertiary hydroxyl group and the isocyanate group of the diisocyanate compound described below is sufficiently performed due to steric hindrance. , The isocyanate group remains in a high proportion in the obtained crosslinked copolymer. As a result, there arises a problem that the weather resistance and storage stability of the obtained cross-linked copolymer are reduced, and that the releasability is remarkably reduced by reacting with the glass constituting the mold in the casting polymerization.

<Component (B)> The specific diisocyanate compound used as the component (B) is dicyclohexylmethane-4,4′-diisocyanate, isophorone diisocyanate and 1,3-
It is at least one diisocyanate compound selected from bis (isocyanatomethyl) cyclohexane.
By using such a specific diisocyanate compound, heat resistance is high, and furthermore, it has excellent weather resistance,
A crosslinked copolymer having high mechanical strength (flexural modulus) can be obtained. When a compound other than the above specific diisocyanate compound, for example, 1,6-hexane diisocyanate, is used as the diisocyanate compound, a crosslinked copolymer having high heat resistance and high mechanical strength cannot be obtained.

Dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate and 1,3-bis (isocyanatomethyl) cyclohexane may be used alone or in combination of the two (B).
Although it can be used as a component, isophorone diisocyanate or 1,3-bis (isocyanatomethyl)
Since the crosslinked copolymer obtained when cyclohexane is used alone is apt to be brittle, dicyclohexylmethane-diol may be used as part or all of the component (B).
It is preferred to use 4,4'-diisocyanate.

In the present invention, the molar number of the hydroxyl group derived from the (meth) acrylic ester monomer having a secondary hydroxyl group used as the component (A) is a, and the dicyclohexylmethane used as the component (B) is B is the number of moles of isocyanate groups derived from 4,4′-diisocyanate, and c is the number of moles of isocyanate groups derived from isophorone diisocyanate and / or 1,3-bis (isocyanatomethyl) cyclohexane used as the component (B). In this case, it is preferable that the following conditions (1) and (2) are satisfied. Condition (1) 0.8 <(b + c) / a <1.2. Condition (2): 0 ≦ c / (b + c) <0.85.

When the value of (b + c) / a is 0.8 or less, a high ratio of isocyanate groups remains in the obtained cross-linked copolymer. In some cases, the resin may react with the glass constituting the mold to significantly reduce the releasability, or may deteriorate the weather resistance and the stability over time. On the other hand, when the value of (b + c) / a is 1.2 or more, a high ratio of hydroxyl groups remains in the obtained cross-linked copolymer, so that the cross-linked copolymer has high hydrophilicity and high water absorption. It is easy to be. Also, c /
When the value of (b + c) is 0.85 or more, the obtained crosslinked copolymer tends to be brittle.

<Component (C)> The component (C) is a monomer capable of undergoing radical copolymerization with the (meth) acrylic ester monomer having a secondary hydroxyl group as the component (A) (hereinafter referred to as “radical”). Also referred to as "copolymerizable monomer"). As such a radical copolymerizable monomer, both a monofunctional monomer having one radical polymerizable double bond and a polyfunctional monomer having two or more radical polymerizable double bonds can be used. it can.

Specific examples of the monofunctional radical copolymerizable monomer include methyl (meth) acrylate and ethyl (meth) acrylate.
Acrylate, n-butyl (meth) acrylate, te
Alkyl groups such as rt-butyl (meth) acrylate and cyclohexyl (meth) acrylate have 1 to 8 carbon atoms.
(Meth) acrylates containing aromatic groups such as lower alkyl (meth) acrylates, benzyl (meth) acrylate, phenoxy (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meth)
(Meth) acrylate having a lower alkyl group via ethylene oxide such as acrylate and diethylene glycol mono (meth) acrylate, isobornyl (meth)
(Meth) acrylates in which an alkyl group is substituted with an isobornyl group such as acrylate, aromatic vinyl compounds such as styrene, α-methylstyrene, divinylbenzene, p-tert-butylstyrene, glycidyl (meth) acrylate, methylglycidyl (meth) (Meth) acrylates having a glycidyl group such as acrylate are exemplified.

Specific examples of the polyfunctional radical copolymerizable monomer include ethylene glycol di (meth) acrylate,
Polyethylene glycol di (meth) acrylate, 1,
4-butanediol di (meth) acrylate, 1,9-
Nonanediol di (meth) acrylate, 2,2-bis {4-methacryloxyethoxyphenyl} propane,
And polyfunctional (meth) acrylates such as 2,2-bis {3,5-dibromo-4-methacryloxyethoxyphenyl} propane and pentaerythritol tetra (meth) acrylate.

These compounds reduce the viscosity of the solution upon radical polymerization described below, increase the heat resistance of the crosslinked copolymer, lower the water absorption of the crosslinked copolymer, For the purpose of imparting properties such as hydrophobicity and hydrophilicity of the surface and special reactivity, etc., it can be appropriately selected and used.

In the present invention, from the viewpoint of improving the adhesion to an adhesive such as an optical adhesive, a vapor-deposited coating layer such as a non-reflective coating layer, a hard coat layer for improving the surface hardness, etc. It is preferable to use a (meth) acrylate having a glycidyl group as a part or all of the component, and its use ratio is 1 to 30% by mass of the total amount of the component (A), the component (B), and the component (C). It is preferred that

<Acrylic Cross-Linked Copolymer> The acrylic cross-linked copolymer constituting the plastic lid material for the solid-state imaging device package of the present invention comprises the component (A) described above,
It is obtained by subjecting the component (B) and the component (C) to a urethanization reaction and a radical polymerization reaction.

In the present invention, a urethanation reaction catalyst and a radical polymerization initiator are added to a monomer mixture consisting of the three components (A), (B) and (C), and under appropriate conditions. It is also possible to produce an acrylic cross-linked copolymer by simultaneously proceeding the urethanization reaction and the radical polymerization reaction. However, at the time of casting polymerization described below, components (A) and (B) are used from the viewpoints of low elution of the sealing material, low polymerization shrinkage, and good release properties from the glass mold. Is reacted in the presence of a urethanization reaction catalyst to produce a (meth) acrylate compound having a urethane bond (hereinafter, also referred to as a “urethane bond-containing prepolymer”), and thereafter, the urethane A solution containing a bond-containing prepolymer, the component (C), and a radical polymerization initiator (hereinafter, referred to as a “radical polymerizable solution”) is prepared, and the radical polymerizable solution is subjected to polymerization treatment. It is preferable to produce an acrylic crosslinked copolymer.

The urethane-bond-containing prepolymer comprises (A)
It can also be produced by adding a urethanization reaction catalyst to a mixture comprising the components and the component (B) and subjecting the components (A) and (B) to a urethanization reaction under appropriate conditions. However, since the obtained urethane bond-containing prepolymer is a considerably viscous liquid or solid, in preparing a radical polymerizable solution, the urethane bond-containing prepolymer is used as a radical copolymerizable monomer as the component (C). It may be difficult to sufficiently dissolve the monomer.
Therefore, when producing the urethane bond-containing prepolymer, it is preferable that the component (A) and the component (B) are subjected to urethanization reaction in the presence of the component (C). In particular,
A urethanization reaction catalyst is added to a mixture of the components (A), (B) and (C), and the components (A) and (B) in the mixture are urethanized. As a result, a solution in which the urethane bond-containing prepolymer as a reaction product is dissolved in the component (C) (hereinafter, referred to as a “reaction product solution”) is obtained. In the above,
When performing the urethanization reaction between the component (A) and the component (B), it is not necessary to use all of the component (C), and the urethanization reaction is performed using a part of the component (C). Component (C) may be added to the reaction product solution.

As the urethanization reaction catalyst, generally used amine catalysts, metal salt catalysts, organometallic catalysts and the like can be used, but specific (meth) acrylate ester catalysts constituting the component (A) can be used. The secondary hydroxyl group of the monomer is
Since the reactivity of the specific diisocyanate compound constituting the component (B) with the isocyanate group is not so high, it is preferable to use a highly active organotin catalyst such as tin octylate, dibutyltin diacetate, or dibutyltin dilaurate. Further, the urethanization reaction between the component (A) and the component (B) can be carried out at the same reaction temperature and reaction time as in a normal urethanization reaction.

By adding a radical polymerization initiator to the reaction product solution thus obtained, a radical polymerizable solution can be prepared. As the radical polymerization initiator, an ordinary organic peroxide-based polymerization initiator can be used. However, tert-butyl peroxy neodecanoate, tert-butyl peroxy neodecanoate, -Butyl peroxypivalate, t
non-aromatic peroxyesters such as tert-butylperoxy-2-ethylhexanoate, tert-butylperoxylaurate, lauroyl peroxide;
It is preferable to use a diacyl peroxide such as 3,5,5-trimethylhexanoyl peroxide. Also, 2,2′-azobis (isobutyronitrile),
2′-azobis (2,4-dimethylvaleronitrile),
An azo radical polymerization initiator such as 1,1'-azobis (cyclohexane-2-carbonitrile) can also be suitably used. Further, an antioxidant, an ultraviolet absorber, a light stabilizer, and other additives can be added to the radical polymerizable solution as needed.

The ratio of the urethane bond-containing prepolymer to the component (C) in the radical polymerizable solution is such that the urethane bond-containing prepolymer: the component (C) is in a weight ratio of 80:20.
２０20: 80 is preferred. If the proportion of the urethane bond-containing prepolymer is too small, the sealing material may be dissolved during casting polymerization described below. On the other hand, if the proportion of the urethane bond-containing prepolymer is too large, the viscosity of the radically polymerizable solution may be too high, making it difficult to obtain an acrylic cross-linked copolymer by cast polymerization.

By subjecting such a radical polymerizable solution to a polymerization treatment, an acrylic cross-linked copolymer constituting the plastic lid material for a solid-state imaging device package of the present invention can be obtained. The specific method of the polymerization treatment is not particularly limited, and a radical polymerization method using a usual polymerization initiator can be employed, but the resulting acrylic cross-linked copolymer is difficult to melt-mold. Therefore, it is preferable to use a casting polymerization method in which a molded product is directly obtained.

When an acrylic crosslinked copolymer is obtained by the cast polymerization method, it is preferable to use a pair of mold plates made of glass, for example, each having an optical plane on one surface as a mold material. More specifically, the pair of mold plates are arranged at regular intervals so that the surfaces having the optical planes face each other, and the side surfaces of these mold plates are surrounded by a sealing material such as a tape or a gasket. By forming a cavity, a monomer mixture containing a radical polymerization initiator is injected into the cavity, and the monomer mixture is heated or irradiated with light to copolymerize the monomer mixture. A sheet-shaped or plate-shaped formed body made of the copolymer is obtained.

According to such a method, the urethane bond-containing prepolymer and the (C)
By copolymerization with the components, a molded article composed of an acrylic cross-linked copolymer having an optical plane on the surface can be directly obtained, and a lid material can be obtained by cutting the molded article as necessary. Therefore, since the surface polishing step, which is an essential step for forming an optical plane in the conventional production of a glass lid material, is not required, the lid material can be easily produced.

In the above description, when a component acting as an organic solvent such as styrene is used as the component (C), a sealing material made of a material having solvent resistance, for example, a gasket made of a fluorine-based rubber is used. However, since the urethane bond-containing prepolymer is dissolved in the component (C), the erosion property of the component (C) is reduced.
It is not necessary to use a material made of a material having high solvent resistance. For example, a material made of silicone rubber can be used. Further, the radical polymerization reaction between the urethane bond-containing prepolymer and the component (C) can be carried out at the same reaction temperature and reaction time as those of a usual radical polymerization reaction.

The molded article made of the acrylic crosslinked copolymer thus obtained is a sheet or plate having a specific gravity of 1.0 to 1.5 and a thickness of 0.1 to 2 mm. Visible light transmittance of 80% or more, flexural modulus of 300
0MPa or more, heat-resistant temperature (Vicat softening point temperature, load 5
kg) has a performance of 130 ° C. or more and a water absorption of 3% or less. Moreover, it does not substantially contain a substance that emits radiation such as α-rays, and is extremely suitable as a lid material for a solid-state imaging device package.

In the plastic lid material for a solid-state imaging device package of the present invention, a diffraction grating having an optical low-pass filter function can be provided on the surface. Such a lid material is suitable as a lid material for a solid-state imaging device package of a solid-state imaging device that requires an optical low-pass filter function for removing high spatial frequency components of subject light and preventing generation of a false signal. is there.

The diffraction grating having the above-mentioned optical low-pass filter function may be provided by directly forming on the surface of the molded article made of the above-mentioned acrylic cross-linked copolymer, or may be provided on the surface of the molded article. It may be provided by stacking diffraction grating layers.

As a method of forming a diffraction grating directly on the surface of a molded article, a negative pattern of the diffraction grating is formed on at least one surface (an inner surface) of at least one of a pair of mold plates in the above-described casting polymerization method. A method for directly producing a molded body having a diffraction grating formed on its surface by performing cast polymerization of a radical polymerizable solution using
A method of forming a diffraction grating by heating and contacting a stamper on which a negative pattern of the diffraction grating is imprinted on the surface of the molded body is exemplified.

As a means for laminating the diffraction grating layer on the surface of the molded body, for example, silicon dioxide (Si
A method of forming a diffraction grating layer by evaporating O ₂ ), uniformly applying a photosensitive resin to the surface of a molded article, exposing the diffraction grating pattern using a mask pattern, and developing the photosensitive resin. A method of forming a diffraction grating layer made of a resin, a film having a diffraction grating formed using an optical resin having excellent transparency (hereinafter referred to as a “diffraction grating film”), and forming the diffraction grating film. And a method of laminating and bonding to a body. When laminating the diffraction grating film on the molded body, when bonding the molded body and the diffraction grating film with an adhesive or an adhesive,
Heat-curable or light-curable adhesives or pressure-sensitive adhesives with excellent transparency, such as epoxy, urethane or acrylic adhesives, or acrylic pressure-sensitive adhesives with excellent transparency and weather resistance An agent can be preferably used.

Further, a hard coat layer, an anti-reflection layer and the like can be formed on the surface of the plastic lid material for a solid-state image sensor package of the present invention by post-processing.
In addition, the lid material of the present invention is formed by forming an optical multilayer film similar to the one usually formed on a glass substrate,
It is also possible to provide a filter function for reducing the transmittance of light rays in a specific wavelength range by utilizing the interference action of the optical multilayer film.

The optical multilayer film is usually formed on the surface of the substrate material.
For the purpose of selectively reducing transmission or reflection of light in a specific wavelength range, a thin film of silicon oxide (SiO ₂ ) or the like, which is a low-refractive-index material having a thickness corresponding to an optical path length of ４ of the light wavelength And a thin film of titanium oxide (TiO ₂ ), which is a high refractive index material, is alternately laminated by using a thin film forming method such as a vacuum evaporation method or a sputtering method. Temperature spontaneously increases, and since the substrate may need to be actively heated in order to improve film forming properties, the substrate is made of a material having excellent heat resistance. It is necessary.
However, since the lid material of the present invention has extremely excellent heat resistance, when a thin film is formed on the surface of the lid material by a vapor deposition method as compared with a normal acrylic resin having low heat resistance. Sufficiently excellent film forming characteristics can be obtained, and therefore, an optical multilayer film having a large number of thin film layers can be formed with high reliability and with sufficient adhesion to a substrate. On the other hand, when a general-purpose polymethyl methacrylate resin is used as a substrate, if a thin film is formed on the surface by an evaporation method, peeling occurs at the interface between the substrate and the optical multilayer film due to the low heat resistance of the material. This is likely to occur, and it is difficult to form an optical multilayer film having good optical characteristics. Further, the optical multilayer film can be formed of a metal or a metal salt, an inorganic oxide, an inorganic sulfide, or the like.

[0041]

Hereinafter, embodiments of the present invention will be described.
The present invention is not limited by these. In the following Examples and Comparative Examples, “parts” means “parts by mass”. “A” is the number of moles derived from a (meth) acrylate monomer having a secondary hydroxyl group, and “b” is the number of moles of isocyanate groups derived from dicyclohexylmethane-4,4′-diisocyanate. ,
“C” represents the number of moles of isocyanate groups derived from isophorone diisocyanate and / or 1,3-bis (isocyanatomethyl) cyclohexane.

Example 1 [Production of urethane bond-containing prepolymer] 14.64 parts of 2-hydroxybutyl methacrylate (component (A))
21.21.11 parts of 2-hydroxy-1,3-dimethacryloxypropane [component (A)] and dicyclohexylmethane-4,4'-diisocyanate [component (B)]
25 parts, 20 parts of styrene [(C) component], 10 parts of α-methylstyrene [(C) component], and 10 parts of glycidyl methacrylate [(C) component] were mixed. In the above, the value of (b + c) / a is 1.0, and c / (b +
The value of c) is 0. The resulting mixture was mixed with di-n-butyltin dilaurate 0.05% as a urethanization reaction catalyst.
And the mixture is subjected to a urethanization reaction between the component (A) and the component (B) in the mixture at 60 ° C. for 4 hours to contain a urethane bond-containing prepolymer as a reaction product. A reaction product solution was obtained.

[Preparation of Radical Polymerizable Solution] After cooling the obtained reaction product solution to room temperature, tert-butyl peroxy-2 was added to the reaction product solution as a polymerization initiator.
A radical polymerizable solution was prepared by adding 1.0 part of -ethylhexanoate.

[Polymerization] A pair of glass mold plates each having an optical plane on one surface and measuring 100 mm × 100 mm × 5 mm are arranged so as to face each other at an interval of 1 mm. Side thickness is 1m
A cavity was formed between each of the mold plates by surrounding with a sealing material made of a silicone rubber gasket having a width of 5 mm and a width of 5 mm. The prepared radical polymerization solution is poured into the cavity, and the solution is heated at 50 ° C. for 8 hours at 65 ° C.
For 3 hours, 1 hour at 80 ° C., and 1 hour at 100 ° C. to perform a polymerization treatment of the radical polymerizable solution, and the thickness of the acrylic cross-linked copolymer is 0.9 mm. A colorless and transparent plate-like molded product was obtained. The molded body was cut into a size of 9 mm × 9 mm to obtain a plastic lid material for a solid-state imaging device package of the present invention.

With respect to the obtained lid material, specific gravity, refractive index (n _D ), light transmittance (JIS K67) at 23 ° C.
14) and the flexural modulus were measured, and the following items were evaluated. [Heat resistance]: The Vicat softening point temperature was measured in accordance with JIS K7206 B method.
When the temperature exceeds 50 ° C., the displacement at 150 ° C. was measured. [Cutting workability]: Using a dicing saw 2H6T (manufactured by Disco Corporation), cut with a diamond blade and observe the etched portion.
When it occurred, it was evaluated as “x”. [Adhesion toughness]: The epoxy composite package material and the lid material are bonded with an epoxy-based thermosetting adhesive, and are held at 0 to 150 ° C. for 2 to 4 hours while fixed with a jig, and then cooled. After that, the lid material was observed and evaluated as “と し て” when no crack or deformation occurred, and as “X” when poor adhesion or crack or deformation occurred. [Solvent resistance]: After the lid material was immersed in methyl alcohol, acetone, and toluene at 23 ° C. for 24 hours, the lid material was observed.
The case where swelling or dissolution or cracks occurred in the solvent was evaluated as “x”. Table 1 shows the above results.

<Example 2> [Production of urethane bond-containing prepolymer] 2-hydroxybutyl methacrylate [component (A)] 21.87 parts,
18.13 parts of dicyclohexylmethane-4,4'-diisocyanate [component (B)], 12 parts of isobornyl methacrylate [component (C)], 30 parts of α-methylstyrene [(C) component], 1 part 15 parts of 1,3-butylene glycol dimethacrylate [component (C)] and 3 parts of glycidyl methacrylate [component (C)] were mixed. In the above, the value of (b + c) / a is 1.0, and c /
The value of (b + c) is 0. To the obtained mixture, 0.03 parts of di-n-butyltin dilaurate as a urethanation reaction catalyst was added, and the components (A) and (B) in the mixture were added at 60 ° C. for 4 hours. By performing a urethanation reaction with, a reaction product solution containing a urethane bond-containing prepolymer as a reaction product was obtained.

[Preparation of Radical Polymerizable Solution] After cooling the obtained reaction product solution to room temperature, 0.8 parts of tert-butyl peroxypivalate as a polymerization initiator is added to the reaction product solution. Thus, a radical polymerizable solution was prepared.

[Polymerization Polymerization] The prepared radically polymerizable solution was poured into the cavity formed in the same manner as in Example 1, and was heated at 40 ° C. for 10 hours, at 65 ° C. for 4 hours, and at 80 ° C. for 1 hour. The radical polymerizable solution was polymerized by heating at 100 ° C. for 1 hour at a different temperature, and the thickness of the acrylic cross-linked copolymer was 0.9 mm.
A colorless and transparent plate-like molded product was obtained. 9 mm
By cutting into a size of × 9 mm, a plastic lid material for a solid-state imaging device package of the present invention was manufactured, and the evaluation was performed in the same manner as in Example 1. Table 1 shows the results.

Example 3 [Production of urethane bond-containing prepolymer] 2-hydroxy-1,3-dimethacryloxypropane [component (A)]
28.76 parts and dicyclohexylmethane-4,4'-
14.60 parts of diisocyanate [component (B)] and 1.64 parts of isophorone diisocyanate [component (B)]
30 parts of styrene [(C) component], 5 parts of 1,3-butylene glycol dimethacrylate [(C) component], 15 parts of glycidyl methacrylate [(C) component], and α-methylstyrene [(C) component 5 parts were mixed. In the above, the value of (b + c) / a is 1.0, and c / (b
+ C) is 0.12. To the obtained mixture, 0.15 parts of di-n-butyltin dilaurate as a urethanization reaction catalyst was added, and the components (A) and (B) in the mixture were mixed at 60 ° C. for 5 hours. By performing the urethanization reaction of Example 1, a reaction product solution containing a urethane bond-containing prepolymer as a reaction product was obtained.

[Preparation of Radical Polymerizable Solution] After cooling the obtained reaction product solution to room temperature,
A radical polymerizable solution was prepared by adding 1.0 part of tert-butyl peroxy-2-ethylhexanoate as a polymerization initiator.

[Polymerization polymerization] A pair of circular glass mold plates each having an optical plane on one surface, a thickness of 5 mm, and a diameter of 120 mm are arranged so as to face each other at an interval of 1.1 mm. A cavity was formed between each of the mold plates by surrounding the side surface of the mold plate with a sealing material made of an adhesive tape having a silicone-based adhesive layer. The prepared radical polymerizable solution was poured into the cavity, and heated at sequentially different temperatures such as 48 ° C. for 10 hours, 65 ° C. for 4 hours, 90 ° C. for 1 hour, and 120 ° C. for 1 hour. The radically polymerizable solution was subjected to a polymerization treatment to obtain a colorless and transparent plate-like molded article made of an acrylic cross-linked copolymer having a thickness of 1.0 mm. This molded body was cut into a size of 9 mm × 9 mm to produce a plastic lid material for a solid-state imaging device package of the present invention, and the evaluation was performed in the same manner as in Example 1.
Table 1 shows the results.

Example 4 [Production of urethane bond-containing prepolymer] 2-hydroxy-1,3-dimethacryloxypropane [component (A)]
24.96 parts and isophorone diisocyanate [(B)
Component] 24.31 parts, α-methylstyrene [(C) component] 10 parts, and methyl methacrylate [(C) component] 1
And 5 parts. To the obtained mixture, 0.1 part of di-n-butyltin dilaurate as a urethanation reaction catalyst was added, and the components (A) and (B) in the mixture were added at 23 ° C. for 1 hour. The reaction product is obtained by adding 15.73 parts of 2-hydroxypropyl methacrylate [component (A)] and further performing the urethanization reaction at 60 ° C. for 5 hours. A reaction product solution containing a urethane bond-containing prepolymer was obtained. In the above, (b + c) / a
Is 1.0, and the value of c / (b + c) is 1.

[Preparation of Radical Polymerizable Solution] After the obtained reaction product solution was cooled to room temperature, 10 parts of glycidyl methacrylate (component (C)) and ethyl acetate as an ultraviolet absorber were added to the reaction product solution. 2-cyano-3,3-
A radical polymerizable solution was prepared by adding 0.2 parts of diphenyl acrylate and 1.2 parts of 1,1-azobis (cyclohexane-2-carbonitrile) as a polymerization initiator.

[Polymerization] A pair of mold plates is 0.9 m
A cavity was formed in the same manner as in Example 3 except that the cavity was arranged at intervals of m, and the prepared radically polymerizable solution was injected into the cavity, and was heated at 68 ° C for 10 hours at 85 ° C.
At 4 ° C. for 1 hour at 110 ° C. to polymerize the radical polymerizable solution, and the thickness of the acrylic cross-linked copolymer is 0.8 mm.
A colorless and transparent plate-like molded product was obtained. 9 mm
By cutting into a size of × 9 mm, a plastic lid material for a solid-state imaging device package of the present invention was manufactured, and the evaluation was performed in the same manner as in Example 1. Table 1 shows the results.

Example 5 [Production of urethane bond-containing prepolymer] 2-hydroxy-1,3-dimethacryloxypropane [component (A)]
23.4 parts, dicyclohexylmethane-4,4'-diisocyanate [(B) component] 26.85 parts, α-methylstyrene [(C) component] 10 parts, and tert-butyl methacrylate [(C) component 20 parts).
To the resulting mixture, 0.1 part of di-n-butyltin dilaurate as a urethanization reaction catalyst was added, and the components (A) and (B) in the mixture were mixed at 60 ° C. for 1 hour. 13. urethanization reaction of 2-hydroxypropyl methacrylate [component (A)]
75 parts were added, and the urethane reaction was further performed at 60 ° C. for 3 hours to obtain a reaction product solution containing a urethane bond-containing prepolymer as a reaction product. In the above, the value of (b + c) / a is 1.0, and the value of c / (b + c) is 0.

[Preparation of Radical Polymerizable Solution] After cooling the obtained reaction product solution to room temperature, 5 parts of glycidyl methacrylate [(C) component] was added to the reaction product solution.
A radical polymerizable solution was prepared by adding 0.8 parts of tert-butyl peroxy-2-ethylhexanoate as a polymerization initiator.

[Polymerization] A pair of mold plates is 1.3 m long.
A cavity was formed in the same manner as in Example 3 except that the cavity was arranged at intervals of m, and the prepared radically polymerizable solution was injected into the cavity, and was heated at 68 ° C for 10 hours at 85 ° C.
At 4 ° C., 1 hour at 110 ° C., and 1 hour at 130 ° C. to perform a polymerization treatment of the radical polymerizable solution, and the thickness of the acrylic cross-linked copolymer is 1.2 mm. A colorless and transparent plate-like molded product was obtained.
This molded body was cut into a size of 9 mm × 9 mm to produce a plastic lid material for a solid-state imaging device package of the present invention, and the evaluation was performed in the same manner as in Example 1. Table 1 shows the results.

Example 6 26.18 parts of 2-hydroxy-1,3-dimethacryloxypropane [(A) component] and 1,3-bis (isocyanatomethyl) cyclohexane [(B) component] 28 parts, 16.54 parts of 2-hydroxypropyl methacrylate [component (A)],
10 parts of α-methylstyrene [component (C)] and tert
-Butyl methacrylate (component (C)) 20 parts. To the obtained mixture, 0.03 part of di-n-butyltin dilaurate was added as a urethanation reaction catalyst,
By performing the urethanization reaction at 40 ° C. for 3 hours, a reaction product solution containing a urethane bond-containing prepolymer as a reaction product was obtained. After cooling the obtained reaction product solution to room temperature, 5 parts of glycidyl methacrylate [component (C)] and tert-butyl peroxy-2-ethylhexanoate as a polymerization initiator were added to the reaction product solution. A radical polymerizable solution was prepared by adding 0.8 parts. In the above, the value of (b + c) / a is 1.0, and the value of c / (b + c) is 0.

A cavity was formed in the same manner as in Example 3 except that a pair of mold plates was arranged at an interval of 0.9 mm, and the prepared radically polymerizable solution was injected into the cavity. 10 hours, 4 hours at 85 ° C, 1
Polymerization treatment was sequentially performed at 10 ° C. for 1 hour and 130 ° C. for 1 hour at different temperatures to obtain a colorless and transparent plate-like molded product having a center thickness of 0.8 mm. Then, a plastic lid material for a solid-state imaging device package of the present invention was manufactured and evaluated. Table 1 shows the results
Shown in

<Comparative Example 1> 29.88 parts of 2-hydroxyethyl methacrylate having a primary hydroxyl group and dicyclohexylmethane-4,4'-diisocyanate 30.1.
2 parts, 20 parts of α-methylstyrene, and 20 parts of styrene were mixed. To the obtained mixture, 0.03 part of di-n-butyltin dilaurate as a urethanization reaction catalyst was added, and at 40 ° C, 2-hydroxyethyl methacrylate and dicyclohexylmethane-4,4 ′ in the mixture were added. When the urethanization reaction with diisocyanate was performed, when one hour had elapsed since the start of the reaction,
The mixture became cloudy. After cooling the obtained reaction product solution to room temperature, 5 parts of glycidyl methacrylate and 1.0 part of 2,2′-azobis (isobutyronitrile) as a weight initiator were added to the reaction product solution. Then, cast polymerization was carried out in the same manner as in Example 4, but the obtained copolymer was cloudy.

Comparative Example 2 25.26 parts of 2-hydroxybutyl methacrylate and 14.7 of 1,6-hexanediisocyanate which is not a specific diisocyanate compound
4 parts, 12 parts of isobornyl methacrylate, 30 parts of α-methylstyrene, 15 parts of 1,3-butylene glycol dimethacrylate, and glycidyl methacrylate 3
Parts were mixed. To the obtained mixture, 0.03 parts of di-n-butyltin dilaurate as a urethanation reaction catalyst was added, and the mixture was treated with 2-hydroxybutyl methacrylate and 1,6- A urethanation reaction with hexane diisocyanate was performed.
After cooling the obtained reaction product solution to room temperature, a radical polymerizable solution was prepared by adding 0.8 parts of tert-butyl peroxypivalate as a polymerization initiator to the reaction product solution. The prepared radically polymerizable solution was injected into the cavity formed in the same manner as in Example 1, and sequentially at 40 ° C. for 10 hours, 65 ° C. for 4 hours, 80 ° C. for 1 hour, and 100 ° C. for 1 hour. By heating at different temperatures, the radical-polymerizable solution was subjected to a polymerization treatment to obtain a colorless and transparent plate-like molded article having a thickness of 0.9 mm. This molded body was cut into a size of 9 mm × 9 mm to produce a plastic lid material.
The evaluation was performed in the same manner as described above. Table 2 shows the results.

Comparative Example 3 20 parts of methyl methacrylate, 30 parts of ethylene glycol dimethacrylate, 20 parts of dimethylol tricyclodecane diacrylate,
10 parts of glycidyl methacrylate and 20 parts of isobornyl methacrylate were mixed. In the resulting mixture, t
tert-butyl peroxy-2-ethylhexanoate (1.0 part) was added and poured into the cavity formed in the same manner as in Example 3;
4 hours, 1 hour at 90 ° C., and 1 hour at 120 ° C. at different temperatures in order to carry out the polymerization treatment. As a result, the sealing material was dissolved on the way and the monomer leaked,
A molded article could not be obtained.

<Comparative Example 4> The same operation as in Comparative Example 3 was carried out except that a gasket made of a fluorine-based rubber (Viton rubber) was used as a sealing material to obtain a 1.0 mm thick crosslinked copolymer. A colorless and transparent plate-like molded product was obtained. This molded body was cut into a size of 9 mm × 9 mm to produce a plastic lid material.
The evaluation was performed in the same manner as described above. Table 2 shows the results.

<Comparative Example 5> A lid material made of glass having a thickness of 1 mm was prepared, and evaluations were made in the same manner as in Example 1 for items other than heat resistance and bending strength. Table 2 shows the results.

<Comparative Example 6> A lid member made of a polycarbonate resin having a thickness of 1 mm was prepared, and items other than heat resistance were evaluated in the same manner as in Example 1. Table 2 shows the results.

<Comparative Example 7> A lid material made of polymethyl methacrylate resin having a thickness of 1 mm was prepared.
The evaluation was performed in the same manner as described above. Table 2 shows the results.

[0067]

[Table 1]

[0068]

[Table 2]

As is clear from Tables 1 and 2, the lid materials according to Examples 1 to 6 have the same transparency, a lower specific gravity, and are less suitable for cutting than the glass lid materials. It was confirmed that it was excellent. In addition, compared with polycarbonate lid material and polymethyl methacrylate lid material, it has high flexural modulus, excellent cutting workability, excellent bonding toughness, and especially excellent heat resistance and solvent resistance. Was confirmed.

Example 7 In the cast polymerization of a radically polymerizable solution, a silicon dioxide (SiO ₂ ) vapor-deposited film was formed on the inner surface forming a cavity as one of a pair of mold plates. The present invention having a diffraction grating formed on its surface in the same manner as in Example 1 except that a negative pattern of a trapezoidal diffraction grating having a depth of 0.5 μm and a pitch of 0.1 mm is used. A plastic lid material for a solid-state imaging device package was manufactured. When a solid-state imaging device sealed with the lid material was incorporated into a solid-state imaging device and a practical test was performed, it was confirmed that the solid-state imaging device had a good optical low-pass filter function.

Example 8 In the same manner as in Example 1, a transparent plate-like molded article of 0.9 mm in thickness made of an acrylic cross-linked copolymer was obtained, and this molded article was reduced to a size of 9 mm × 9 mm. After cutting, silicon dioxide (SiO ₂ ) is vapor-deposited on the surface to obtain a thickness of 0.5 μm and a pitch of 0.05 m.
A lid material on which a diffraction grating layer having a trapezoidal linear diffraction grating pattern of m was formed. When a solid-state imaging device sealed with the lid material was incorporated into a solid-state imaging device and a practical test was performed, it was confirmed that the solid-state imaging device had a good optical low-pass filter function.

Example 9 A plate-shaped molded article of an acrylic cross-linked copolymer having a size of 80 mm × 80 mm and a thickness of 1 mm obtained in the same manner as in Example 1 was used as a substrate, and this was used as a vacuum deposition apparatus. An optical multilayer film having 40 thin film layers and a total film thickness of 5 μm by alternately depositing silicon dioxide (SiO ₂ ) and titanium oxide (TiO ₂ ) on the surface of the substrate by an electron beam evaporation method. Was formed. FIG. 1 shows the result of measuring the spectral transmission characteristics of this lid material. In addition, a peeling test using an adhesive tape was performed using the lid material on which the optical multilayer film was formed as a sample, but no peeling of the optical multilayer film from the substrate was observed. In addition, the lid material was left for 100 hours at a high temperature and high humidity of 60 ° C. and a relative humidity of 90%, and then a similar peeling test was performed. In this case, however, the peeling of the optical multilayer film from the substrate was not observed at all. I couldn't.

Comparative Example 8 An optical multilayer film was formed in the same manner as in Example 9 except that a plate-like molded body made of polymethyl methacrylate resin was used as a substrate. However, the optical multilayer film was peeled off. It could not be put to practical use.

[0074]

The plastic lid material according to the present invention has a low specific gravity, is excellent in moldability, and is excellent in transparency, adhesive toughness, heat resistance, and solvent resistance. It has a sufficiently high strength as a package lid material.

According to the production method of the present invention, a molded article of an acrylic crosslinked copolymer having a diffraction grating having an optical low-pass filter function formed on its surface by copolymerizing a mixture of specific monomers Can be obtained directly, so that a lid member on which a diffraction grating having an optical low-pass filter function is formed can be advantageously produced.

[Brief description of the drawings]

FIG. 1 is a curve diagram showing a spectral transmission characteristic of a lid material according to one embodiment of the present invention.

Claims (9)

[Claims] 1. The following component (A) and the following component (B):
A plastic lid material for a solid-state imaging device package, comprising an acrylic cross-linked copolymer obtained by subjecting the following component (C) to a urethanization reaction and a radical polymerization reaction. (A) component: (meth) acrylate monomer having a secondary hydroxyl group (B) component: dicyclohexylmethane-4,4′-diisocyanate, isophorone diisocyanate and 1,1
At least one diisocyanate compound selected from 3-bis (isocyanatomethyl) cyclohexane (C) component: a monomer capable of being radically copolymerized with (A) component 2. A radical polymerization reaction of a (meth) acrylate compound having a urethane bond obtained by a urethanization reaction of the following component (A) and the following component (B) with the following component (C): A plastic lid material for a solid-state imaging device package, comprising the obtained acrylic cross-linked copolymer. (A) component: (meth) acrylate monomer having a secondary hydroxyl group (B) component: dicyclohexylmethane-4,4′-diisocyanate, isophorone diisocyanate and 1,1
At least one diisocyanate compound selected from 3-bis (isocyanatomethyl) cyclohexane (C) component: a monomer capable of being radically copolymerized with (A) component 3. The plastic for a solid-state imaging device package according to claim 1, wherein a (meth) acrylate compound having a glycidyl group is used as a part or all of the component (C). Made of lid material. 4. The solid-state imaging device package according to claim 1, wherein dicyclohexylmethane-4,4′-diisocyanate is used as part or all of the component (B). Plastic lid material. 5. The number of moles of hydroxyl groups derived from the (meth) acrylate monomer having a secondary hydroxyl group is a, the number of moles of isocyanate groups derived from dicyclohexylmethane-4,4′-diisocyanate is b, The following condition (1) and condition (2) are satisfied when the number of moles of isocyanate groups derived from isophorone diisocyanate and / or 1,3-bis (isocyanatomethyl) cyclohexane is c. 5. A plastic lid material for a solid-state imaging device package according to item 4. Condition (1) 0.8 <(b + c) / a <1.2 Condition (2) 0 ≦ c / (b + c) <0.85 6. The plastic lid material for a solid-state imaging device package according to claim 1, wherein a diffraction grating having an optical low-pass filter function is formed on the surface. 7. The plastic lid material for a solid-state imaging device package according to claim 1, wherein a diffraction grating layer having an optical low-pass filter function is laminated on the surface. . 8. The method according to claim 1, wherein an optical multilayer film for selectively reducing transmission or reflection of a light beam in a specific wavelength range is formed on the surface. Plastic lid material for solid-state imaging device package. 9. A cavity is formed by arranging a pair of mold plates, each having a negative pattern of a diffraction grating formed on one surface of at least one of the mold plates, with the respective surfaces facing each other. In the tee, a (meth) having a urethane bond obtained by a urethanization reaction between the following component (A) and the following component (B)
A method for producing a plastic lid material for a solid-state imaging device package, comprising a step of obtaining a molded article of an acrylic crosslinked copolymer by copolymerizing an acrylate compound and the following component (C): . (A) component: (meth) acrylate monomer having a secondary hydroxyl group (B) component: dicyclohexylmethane-4,4′-diisocyanate, isophorone diisocyanate and 1,1
At least one diisocyanate compound selected from 3-bis (isocyanatomethyl) cyclohexane (C) component: a monomer capable of being radically copolymerized with (A) component