JP2009286942A - Resin for dust control, and camera module using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin for dust control that can suitably capture abrasion powder and dust generated inside precision electronic parts for a long period and does not cause corrosion inside the parts, and a camera module fitted with the resin for dust control. <P>SOLUTION: The resin for dust control is obtained by hardening with active energy rays a composition containing a compound (A) having a number average molecular weight of 4,000 to 20,000 and two or more maleimide groups. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dustproof resin for removing dust generated inside precision electronic components. Further, the present invention relates to a camera module using the dustproof resin.

  In recent years, information devices have been reduced in size and functionality, and dust generated in precision electronic components can cause functional problems. For example, much of the wear powder generated by the operation of the camera shutter, etc. is not scattered in the air at the same time as it is generated, and adheres to the periphery of the generated part such as the head of the connecting shaft until the exposure operation stops. It is scattered in the air by a large impact generated when it stops. As a result, a part of the material scattered in the apparatus jumps directly to the imaging surface of the image sensor or the photosensitive surface of the film (hereinafter, generically referred to as “imaging surface”) and causes an abnormality. Also, most of those that did not fly to the imaging plane due to the above-mentioned scattering remain in the apparatus and are temporarily attached to the surface of each member, and are raised when the next exposure operation is stopped. A part of the powder is directed to the image plane along with newly generated wear powder. Such repetition includes dust that has entered from the outside of the camera, and in the same way, it comes to the image plane along with wear powder. Therefore, how to prevent wear dust generated by the operation of the shutter and dust entering from the outside from repeatedly rising in the apparatus, particularly, not soaring near the image plane. It is important to do so. For example, Patent Document 1 describes a camera characterized in that an adhesive sheet is installed toward the lens side so that abrasion powder or the like can be suitably captured in a region near the imaging surface.

  Even in the case of an image forming apparatus typified by a digital still camera using an image sensor, an imaging apparatus typified by a digital movie camera, and a projection apparatus typified by a projector, it is preferable that dust adheres to the imaging surface of the image sensor. A subject image cannot be obtained. In the case of an apparatus using these image sensors, there is a problem even if the dust is fine. That is, if the dust is fine, it will not be a problem at first, but it will gradually adhere to the imaging surface and the filter on the front surface of the imaging surface, and this will gradually affect all of the captured images. It will come out. For this reason, in the case of an apparatus using the image sensor as described above, it is necessary to take some measures against any fine dust.

Japanese Patent Application Laid-Open No. 2004-85942

  However, the pressure-sensitive adhesive sheet described in Patent Document 1 does not specify what the pressure-sensitive adhesive component is. A normal pressure-sensitive adhesive sheet has a problem that dust cannot be captured over a long period in which precision electronic components are used. Further, if the adhesive is in the form of a sheet, it is difficult to install it in a minute part inside the downsized electronic component. Furthermore, when there is a component that volatilizes or bleeds from the pressure-sensitive adhesive, a serious problem occurs that the inside of the component corrodes.

  The present invention has been made in view of the above problems, and its purpose is to be able to properly capture wear powder and dust generated inside a precision electronic component over a long period of time, and to prevent corrosion inside the component. The object is to provide a dustproof resin that does not occur. Another object of the present invention is to provide a camera module using the dustproof resin.

As a result of intensive studies in view of the above problems, the present inventor has found that a composition containing a compound having two or more maleimide groups uses a dustproof resin cured by active energy rays, and has a dustproof property inside the component for a long period of time. In addition, the inventors found that no corrosion occurs inside the parts and completed the present invention.
In the present invention, a function capable of suitably capturing the wear powder and dust generated inside the precision electronic component for a long period of time is called dust resistance.

［但し、式（１）において、Ｒ¹は水素、アルキル基、アリール基、アリールアルキル基又はハロゲン原子を表す。］
３．上記式（１）において、Ｒ¹が水素又は炭素数４以下のアルキル基で表されるマレイミド基を２個以上有する化合物である上記２に記載の防塵用樹脂。
４．上記化合物（Ａ）が、２５℃で液状であり、かつ、ポリエーテル骨格を有することを特徴とする上記１〜３のいずれかに記載の防塵用樹脂。
５．撮像レンズと、該撮像レンズを保持するレンズ鏡筒と、撮像レンズより入射された光を受光して映像信号を生成する撮像素子と、撮像素子から出力された映像信号が入力され、信号処理を行う回路基板を備えたカメラモジュールであって、
撮像レンズと対向して設置された撮像素子との間であり、かつ、撮像レンズと撮像素子以外の部分に上記１〜４のいずれかに記載の防塵用樹脂が塗布されていることを特徴とするカメラモジュール。
６．上記撮像レンズと撮像素子以外の部分が、撮像素子の周囲に配置された地板であることを特徴とする上記５に記載のカメラモジュール。 That is, the present invention is as follows.
1. A dustproof resin obtained by curing a composition containing a compound (A) having two or more maleimide groups having a number average molecular weight of 4000 to 20000 with active energy rays.
2. 2. The dustproof resin according to 1 above, wherein the compound (A) is a compound having two or more maleimide groups represented by the following formula (1).

[However, in Formula (1), R < ¹ > represents hydrogen, an alkyl group, an aryl group, an arylalkyl group, or a halogen atom. ]
3. 3. The dustproof resin according to 2 above, wherein in the formula (1), R ¹ is a compound having two or more maleimide groups represented by hydrogen or an alkyl group having 4 or less carbon atoms.
4). 4. The dustproof resin as described in any one of 1 to 3 above, wherein the compound (A) is liquid at 25 ° C. and has a polyether skeleton.
5. An imaging lens, a lens barrel that holds the imaging lens, an imaging device that receives light incident from the imaging lens and generates a video signal, and a video signal output from the imaging device are input to perform signal processing A camera module with a circuit board to perform,
The dustproof resin according to any one of the above 1 to 4 is applied between the image pickup lens and the image pickup device disposed so as to face the image pickup lens and in a portion other than the image pickup lens and the image pickup device. Camera module.
6). 6. The camera module as described in 5 above, wherein the portion other than the imaging lens and the imaging device is a ground plate arranged around the imaging device.

  As described above, the dustproof resin according to the present invention is obtained by curing a composition containing a compound having two or more maleimide groups having a number average molecular weight of 4000 to 20000 with active energy rays. Therefore, even when the dustproof resin is applied to the inside of a precision electronic component, the dustproof resin is maintained for a long period of time, and corrosion inside the component does not occur. The dustproof resin can be applied to a minute portion inside the camera module.

  An embodiment of the present invention will be described as follows, but the present invention is not limited to this.

[1] Dust-proof resin The dust-proof resin according to the present invention is obtained by curing a composition containing a compound (A) having two or more maleimide groups with active energy rays. Here, the composition containing the compound (A) having two or more maleimide groups will be specifically described.

  The composition of the present invention essentially comprises a compound (A) having two or more maleimide groups [hereinafter also referred to as “maleimide compound”]. As the maleimide group in the component (A), various functional groups can be used, but those represented by the following formula (1) are preferable.

[However, in Formula (1), R < ¹ > represents hydrogen, an alkyl group, an aryl group, an arylalkyl group, or a halogen atom. ]

In the formula (1), R ¹ is preferably hydrogen or an alkyl group having 4 or less carbon atoms, particularly preferably hydrogen or a methyl group. It is because it is excellent in curability when irradiated with active energy rays.

  Since the component (A) used in the present invention has a maleimide group, the maleimide group is dimerized by irradiation with active energy rays to cross-link the molecules of the compound. In addition, even when the maleimide group is cured with ultraviolet rays or visible light, it can cause a dimerization reaction by irradiation with ultraviolet rays or visible light with or without a photopolymerization initiator.

(A) As a molecular weight of a component, a number average molecular weight is 4000-20000. More preferably, it is 6000-18000. If the number average molecular weight is less than 4000, the adhesive strength and tack of the cured coating film may be reduced. If the number average molecular weight exceeds 20000, the viscosity of the composition becomes too high and the coating property is reduced. Since the maleimide group concentration which is a reactive site is lowered, curability by active energy rays is lowered.
In the present invention, the number average molecular weight is a value obtained by converting the molecular weight measured by gel permeation chromatography (hereinafter, also referred to as “GPC”) with reference to the molecular weight of polystyrene, using tetrahydrofuran as a solvent. . In addition, when the component (A) is a water-soluble polymer, the number average molecular weight is a value obtained by converting a molecular weight measured by GPC using a phosphate buffer as a solvent based on the molecular weight of polyethylene oxide. It is.

  In addition, the component (A) in the present invention is preferably liquid at 25 ° C. Thereby, handling of coating work etc. becomes easy. On the other hand, those that are solid at room temperature are difficult to handle, and the cured coating film has a high elastic modulus and may have insufficient dustproof performance.

The skeleton of the component (A) according to the present invention is not particularly limited, and examples thereof include a polyether skeleton and a polyester skeleton. (A) Although what was manufactured by the various method can be used for a component, the following 3 types of compounds are preferable at the point which manufacture is easy.
(I) An addition reaction product of a prepolymer having two or more isocyanate groups at a terminal and a compound having a maleimide group and an active hydrogen group.
(Ii) a prepolymer having two or more carboxyl groups at the terminal, an esterification reaction product of a compound having a maleimide group and an active hydrogen group (iii) a prepolymer having two or more hydroxyl groups at the terminal, and a maleimide group A carboxylic acid esterification reaction product.
Hereinafter, the compounds (i) to (iii) will be described.

Compound (i) includes a prepolymer having two or more isocyanate groups at the terminal (hereinafter also referred to as “urethane prepolymer”), a compound having a maleimide group and an active hydrogen group (hereinafter referred to as “maleimide active hydrogen compound”). It is produced by reacting 2 moles or more of maleimide active hydrogen compound with 1 mole of urethane prepolymer.
Hereinafter, the urethane prepolymer and the maleimide active hydrogen compound will be described.

  As the urethane prepolymer, various compounds can be used as long as they have two or more isocyanate groups at the molecular ends. Examples of the urethane prepolymer include a reaction product of a polyol having two or more hydroxyl groups (hereinafter also referred to as “polyol”) and a polyisocyanate having two or more isocyanate groups (hereinafter also referred to as “polyisocyanate”). Is mentioned.

  Examples of the polyol include polyether polyol and polyester polyol. Two or more kinds can be used in combination as required.

  Polyether polyols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polybutylene glycol and polytetramethylene glycol; ethylene glycol, propanediol, propylene glycol, tetramethylene glycol, pentamethylene glycol, hexanediol, neopentyl glycol, Alkylene glycols such as glycerin, trimethylolpropane, pentaerythritol, diglycerin, ditrimethylolpropane and dipentaerythritol, ethylene oxide modified products, propylene oxide modified products, butylene oxide modified products and tetrahydrofuran modified products; Copolymer, Copolymer weight of propylene glycol and tetrahydrofuran , Copolymers of ethylene glycol and tetrahydrofuran; hydrocarbon-based polyols such as polyisoprene glycol, hydrogenated polyisoprene glycol, polybutadiene glycol and hydrogenated polybutadiene glycol; and polytetramethylene hexaglyceryl ether (hexaglycerin modified tetrahydrofuran) Etc.

Of these, preferred are polyether polyols that essentially require propylene oxide units. Thereby, the obtained maleimide compound can be made into a liquid thing.
In the case of using a polyether polyol having a propylene oxide unit and an ethylene oxide unit, the proportion of the propylene oxide unit is preferably a high proportion of the propylene oxide unit when the oil component is blended. Based on the total amount of propylene oxide units and ethylene oxide units, those having 30 to 100% by mass of propylene oxide units are preferred, and those having 60 to 100% by mass are more preferred. When water or a water-soluble compound (hereinafter collectively referred to as “aqueous component”) is blended, specifically, the propylene oxide unit is preferably 1 to 90% by mass, and preferably 15 to 90% by mass. Are more preferred.

  The polyester polyol is a random copolycondensation product of a polyvalent carboxylic acid and a polyhydric alcohol. Among these, aliphatic polyester polyols are preferable because they are excellent in curability by active energy rays of the composition.

  Here, various polycarboxylic acids can be used as long as they have two or more carboxyl groups in the molecule. Specifically, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, eicoic acid diacid, 2,6-naphthalenedicarboxylic acid, trimellitic acid, glutaric acid, 1,9 -Nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, malonic acid, fumaric acid, 2,2-dimethylglutaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid Examples include acids, itaconic acid, maleic acid, 2,5-norbornane dicarboxylic acid, 1,4-terephthalic acid, 1,3-terephthalic acid, dimer acid, and paraoxybenzoic acid. Among these, aliphatic dicarboxylic acids are preferable, and adipic acid and sebacic acid are more preferable. Two or more polycarboxylic acids can be used in combination as required.

  Any polyhydric alcohol can be used as long as it has two or more hydroxyl groups in the molecule. Specifically, butylethylpropanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol and polyethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,2-octanediol, 1,8-octanediol, 1,9-nonanediol, 1,2, decanediol, 1,10-decanediol, 2 , 2-Dimethyl-1,3-propanediol, 2,2,4-trimethyl-1,6 Hexanediol, 1,3-cyclohexanedimethanol and 1,4-cyclohexane dimethanol, etc. diol dimer acid and 2-methyl-1,8-octanediol and the like. Among these, aliphatic diols are preferable, and 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, Dimer acid diol and 2-methyl-1,8-octanediol are more preferable because the resulting composition has low viscosity and excellent dust resistance. Two or more polyhydric alcohols can be used in combination as required.

  As a method for producing the polyester polyol, a general esterification reaction may be followed, and examples thereof include a method in which a polyvalent carboxylic acid and a polyhydric alcohol are heated with stirring in the presence of a catalyst.

  As said catalyst, the catalyst normally used by esterification reaction can be used, A base catalyst, an acid catalyst, a metal alkoxide, etc. are mentioned. Examples of the base catalyst include metal hydroxides such as sodium hydroxide and potassium hydroxide, and amines such as triethylamine, N, N-dimethylbenzylamine and triphenylamine. Examples of the acid catalyst include sulfuric acid and paratoluenesulfonic acid. As the metal alkoxide, an alkoxide of titanium, tin or zirconium is preferable. Specific examples of these metal alkoxides include tetraalkyl titanates such as tetrabutyl titanate; tin alkoxides such as dibutyltin oxide and monobutyltin oxide; and zirconium alkoxides such as zirconium tetrabutoxide and zirconium isopropoxide.

  What is necessary is just to set suitably as reaction temperature and time in esterification reaction according to the objective. As reaction temperature, 80-220 degreeC is preferable.

  As the aliphatic polyester polyol, commercially available products can be used. For example, the product names “Kuraray polyol P-5010” and “Kuraray polyol P-5050” manufactured by Kuraray Co., Ltd., products manufactured by Kyowa Hakko Kogyo Co., Ltd. Examples include the names “Kyowapol 5000PA”, “Kyowapol 3000PA”, and trade name “Dynacoll7250” manufactured by Degussa Japan.

Any polyisocyanate can be used as long as it has two or more isocyanate groups in the molecule, and diisocyanate is preferred. Specifically, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, 4,4′-diphenylene diisocyanate, 1,5-octylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexa Methylene diisocyanate, pentamethylene diisocyanate, 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methyl 2,4-cyclohexane diisocyanate, methyl 2,6-cyclohexane diisocyanate, diphenylmethane Diisocyanate, 1,4-bis (isocyanate methyl) cyclohexane, 1,3-bis (isocyanate methyl) Hexane, isophorone diisocyanate and carbodiimide-modified 4,4'-diphenylmethane diisocyanate. Among these, alicyclic or aliphatic isocyanates are preferable in that they are excellent in curability by active energy rays of the composition. As the alicyclic or aliphatic isocyanate, hexamethylene diisocyanate and isophorone diisocyanate are preferable. Polyisocyanate can use 2 or more types together as needed.
In the present invention, the amount of the polyisocyanate with respect to the polyol in producing the urethane prepolymer is preferably in a range in which the equivalent ratio of group-NCO / group-OH is 1 to 3, more preferably 1.5 to 2.5. And particularly preferably 1.8 to 2.2.

  The urethane prepolymer may be produced according to a conventional method. For example, a method of heating a polyol and a polyisocyanate in the presence of a catalyst can be mentioned. As a catalyst, the catalyst used by a general urethanation reaction can be used, for example, a metal compound, an amine, etc. are mentioned. Examples of metal compounds include tin catalysts such as dibutyltin dilaurate and dioctyltin dilaurate; lead catalysts such as lead dioctylate; zirconium such as K-KAT XC-4025 and K-KAT XC-6212 (KING INDUSTRIES, INC) System catalysts; aluminum catalysts such as K-KAT XC-5217 (KING INDUSTRIES, INC.); And titanate catalysts such as tetra 2-ethylhexyl titanate. Examples of the amine include triethylamine, N, N-dimethylbenzylamine, triphenylamine, and triethylenediamine. In the production of the urethane prepolymer, a general radical polymerization inhibitor such as hydroquinone and triethylamine can be used as necessary for the purpose of preventing gelation during the reaction.

  Furthermore, a phosphorus compound can be blended during the production of the urethane prepolymer. By blending the phosphorus compound, the action of the catalyst used during esterification and ring-opening polyaddition can be stopped. If the activity of the catalyst is not deactivated, the obtained urethane prepolymer is stored in the presence of moisture, or is heated in the presence of moisture in the next reaction, or the cured film of the resulting maleimide compound and composition is formed. When stored in the presence of moisture, a transesterification reaction may occur and the physical properties of the composition may be significantly reduced.

  As a phosphorus compound, the inorganic or organic phosphorus compound etc. which are mentioned by following (i)-(e) are mentioned.

(Ii) Phosphoric acid and its alkyl esters Examples of phosphoric acid alkyl esters include trialkyl phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trinonyl phosphate, and triphenyl phosphate.

(B) Phosphonic acid organic esters such as dibutylbutylphosphonate.

(C) Phosphorous acid Used alone or in combination with other phosphorus compounds, it has the most powerful hue stabilizing effect and oxidative degradation preventing effect.

(D) Organic esters of phosphorous acid Examples include dibutyl hydrogen phosphite and triphenyl phosphite. However, triphenyl phosphite may deteriorate the properties of the polyester skeleton in the maleimide compound, and it is necessary to pay attention to the amount of triphenyl phosphite added.

(E) Other inorganic phosphorus compounds such as polyphosphoric acid.

  The amount of the phosphorus compound used may be appropriately set according to the molecular weight of the phosphorus compound (phosphorus atom content), and is generally preferably 0.001 to 3 parts by mass with respect to 100 parts by mass of the polyester polyol. More preferably, it is 0.01-1 mass part. When the amount of the phosphorus compound used is less than 0.001 part by mass, the effect of addition is not recognized, and when it is more than 3 parts by mass, the effect does not increase.

  As the maleimide active hydrogen compound, an alcohol having a maleimide group (hereinafter also referred to as “maleimide alcohol”) is preferable. Examples of maleimide alcohol include maleimide alkyl alcohol represented by the following formula (2).

In the formula (2), R ² represents an alkylene group, preferably a linear or branched alkylene group having 1 to 6 carbon atoms. R ¹ is the same group as in formula (1).

  (A) As a manufacturing method of a component, what is necessary is just to manufacture a urethane prepolymer and a maleimide active hydrogen compound according to a general urethanation reaction. Specific examples of the urethanization reaction include the same methods as described above.

In the production of the component (A), it is preferable to react in the presence of an antioxidant in order to prevent discoloration of the resulting maleimide compound. Examples of antioxidants include phenolic, phosphite triester and amine antioxidants which are generally used. Examples of the antioxidant include JP-B 36-13738, JP-B 36-20041, and JP-B. Examples thereof include compounds described in Japanese Patent Publication No. 36-20042 and Japanese Patent Publication No. 36-20043.
Various phenolic antioxidants can be used, such as butylhydroxytoluene, pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate is particularly preferred.
The phenolic antioxidant can be used in combination with an acid value zinc in order to enhance its effect.
The mixing ratio of the antioxidant is preferably 0.01 to 2 parts by mass per 100 parts by mass of the urethane prepolymer. If this proportion is less than 0.01 parts by mass, sufficient effects due to the blending of the antioxidant may not be exhibited, and even if blended more than 2 parts by mass, no further effect is expected, and this is costly. Disadvantageous.
Moreover, you may mix | blend the above-mentioned phosphorus compound at the time of maleimide compound manufacture.
(A) In manufacture of a component, in order to remove the trace amount impurity contained in the maleimide compound obtained and to improve safety | security further, it can refine | purify. There is no restriction | limiting in particular regarding a refinement | purification method, What is necessary is just to follow a well-known method. For example, a method of adding a washing solvent to the obtained maleimide compound, separating the impurities after extraction using the difference in solubility between the maleimide compound and the impurities to be removed, and then removing the solvent, and the like.

  Compound (ii) is an esterification reaction product of a prepolymer having two or more carboxyl groups at the terminal (hereinafter also referred to as “carboxylic acid prepolymer”) and a maleimide active hydrogen compound. Examples of the carboxylic acid prepolymer include those produced using the same polycarboxylic acid and polyol or polyhydric alcohol as described above. Examples of the maleimide active hydrogen compound include those described above. The esterification reaction method of the carboxylic acid prepolymer and the maleimide active hydrogen compound may follow the same method as described above. Compound (ii) can be preferably used when a lower viscosity is required as a maleimide compound.

  Compound (iii) is an esterification reaction product of a prepolymer having two or more hydroxyl groups at its terminal (hereinafter referred to as “polyol prepolymer”) and a carboxylic acid having a maleimide group (hereinafter also referred to as “maleimide carboxylic acid”). It is. Examples of the polyol prepolymer include the same polyols. As the maleimide carboxylic acid, various compounds can be used, and a compound represented by the following formula (3) is preferable.

In formula (3), R ³ represents an alkylene group, preferably a linear or branched alkylene group having 1 to 6 carbon atoms. R ¹ is the same group as in formula (1).

  In addition to the essential components, various components can be blended in the composition of the present invention as necessary. Each component will be described below.

As described above, the composition of the present invention is easily cured by active energy rays, and further contains no photopolymerization initiator or a small amount of photopolymerization initiator even when cured by ultraviolet rays or visible light. Thus, it has excellent curability, but if necessary, a photopolymerization initiator or the like can be blended. In the case of blending a photopolymerization initiator, examples of the photopolymerization initiator include benzoin and its alkyl ethers, acetophenones, anthraquinones, thioxanthones, ketals, benzophenones, xanthones, acylphosphine oxides, α- And diketones. Moreover, in order to improve the sensitivity by an active energy ray, a photosensitizer can also be used together. Examples of the photosensitizer include benzoic acid and amine photosensitizers. These can also be used in combination of two or more. As these compounding ratios, 0.01-10 mass parts is preferable with respect to 100 mass parts of (A) component.
As the photopolymerization initiator, benzophenones and thioxanthones are preferable because they have a high effect of improving the curing rate of the composition.

  The composition of the present invention has reactive unsaturated groups such as (meth) acrylic monomers and (meth) acrylic oligomers in order to enhance the dustproof performance of the cured coating film or to adjust the sensitivity of the composition. You may mix | blend a compound. As the (meth) acrylic monomer, alkyl acrylate or alkyl methacrylate [hereinafter, acrylate or methacrylate is represented as (meth) acrylate], hydroxyalkyl (meth) acrylate, (meth) acrylate of phenol alkylene oxide adduct, glycol mono Or, di (meth) acrylate, polyol poly (meth) acrylate, and poly (meth) acrylate of a polyol alkylene oxide adduct are exemplified. Examples of (meth) acrylic oligomers include urethane (meth) acrylate oligomers, polyester (meth) acrylate oligomers, and epoxy (meth) acrylate oligomers. As a compounding ratio of the compound which has a reactive unsaturated group, 50 mass parts or less are preferable with respect to 100 mass parts of (A) component, More preferably, it is 20 mass parts or less.

  A polymer may be added to the composition of the present invention in order to adjust the viscosity before curing and the dustproof performance after curing. Although it does not specifically limit as the said polymer, (meth) acrylate type polymer, polystyrene, polyolefin, etc. are mentioned. Among these, a (meth) acrylate polymer having a maleimide group is preferable because it is crosslinked with the component (A) of the present invention in curing.

  In the composition of the present invention, a compound having one maleimide group can be used in combination as long as the curability by irradiation with active energy and the performance of the cured coating film are not impaired. Examples of the compound include a compound having one maleimide group in the same skeleton as described above and a compound having a maleimide group and an ethylenically unsaturated group. When the component (A) of the present invention is a polymer polyol produced from the above-mentioned radical polymerizable monomer, the polymer polyol has two or more hydroxyl groups in one molecule and one molecule. A mixture with one having one hydroxyl group may be used. In this case, the resulting compound is a mixture of a compound having two or more maleimide groups and a compound having one maleimide group, which can be used as it is. The blending ratio of the compound having one maleimide group is preferably 80 parts by mass or less, more preferably 50 parts by mass or less, with respect to 100 parts by mass of the component (A).

  The composition of the present invention may contain a tackifier in order to lower the glass transition temperature (hereinafter also referred to as “Tg”) of the cured coating film or to improve the dustproof performance. Various tackifiers can be used, and examples thereof include natural resins such as rosin resins and terpene resins and derivatives thereof, and synthetic resins such as petroleum resins. Among these, those having no double bond or having a small ratio of double bonds are preferable because the inhibition of curing by active energy rays of the composition is small. As a compounding ratio of the tackifier, the ratio of the tackifier is preferably 50 parts by mass or less, more preferably 10-30 parts by mass with respect to 100 parts by mass of the total amount of the component (A) and the tackifier. Part. When the compounding amount of the tackifier exceeds 50 parts, the viscosity of the composition becomes too high, and the coating property is lowered.

  In order to increase the cohesive force, the composition of the present invention may be used by adding a crosslinking agent that reacts promptly at room temperature for the purpose of crosslinking between the molecules of the polymer. Examples of the crosslinking agent include polyvalent isocyanate compounds, polyoxazoline compounds, epoxy resins, aziridine compounds, polycarbodiimide resins, and coupling agents.

  (A) When using polyester as a raw material as a component, you may mix | blend an acid mask agent with a composition. Polyester is generally known to hydrolyze and lower its molecular weight when used for a long time under severe conditions such as high temperature and humidity. In this case, if an acid mask agent is blended, a carboxyl group generated by hydrolysis can be trapped and further hydrolysis can be prevented. Examples of the acid masking agent include carbodiimide compounds, oxazoline compounds, and epoxy compounds. As a compounding ratio of an acid mask agent, 0.01-2 mass parts is preferable per 100 mass parts of (A) component.

A filler may be added to the composition containing the maleimide compound of the present invention in order to enhance coloring and adhesion performance. Specific examples of the filler include various silicas, dyes, calcium carbonate, magnesium carbonate, titanium oxide, iron oxide, and glass fiber. Moreover, you may mix | blend radical polymerization inhibitors, such as hydroquinone and hydroquinone monomethyl ether, as needed.
In addition to these, antifoaming agents, dyes and pigments, thickeners, lubricants, film forming aids, fillers, plasticizers, antistatic agents, fiber auxiliaries, cleaning agents, antistatic agents, leveling agents, General additives used in adhesives and pressure-sensitive adhesives such as dispersion stabilizers, hydrophilic resins, latexes, wetting agents, and leveling improvers can be used in a commonly used proportion. In addition, antioxidants such as dibutylhydroxytoluene and butylhydroxyanisole; preservatives such as methyl paraoxybenzoate and propyl paraoxybenzoate; and general additives used in skin patches such as emulsifiers are usually used. Can be used in combination. Moreover, in order to adjust a viscosity, an organic solvent can also be mix | blended as needed. Furthermore, the above-mentioned phosphorus compound and antioxidant can also be mix | blended.

[2] Camera Module The camera module of the present invention is an electronic component incorporated in a portable information terminal such as a mobile phone, a notebook personal computer, or a PDA (Personal Digital Assistant). This type of camera module includes an imaging lens, a lens barrel that holds the imaging lens, an imaging element such as a CCD or CMOS that receives light incident from the imaging lens and generates a video signal, and outputs from the imaging element A circuit board or the like that receives the received video signal and performs predetermined signal processing is provided.

  Hereinafter, an example of a camera module (hereinafter also referred to as “module”) as an imaging lens will be described (see FIG. 1). This module receives an image pickup lens 2, a lens barrel 3 that holds the image pickup lens, an image pickup device 8 that is arranged to face the image pickup lens, and a video signal output from the image pickup device, and receives a predetermined signal. It is a part provided with the circuit board 10 which processes. Further, the module may include a camera diaphragm 4, various filters 5, and the like.

The composition containing the maleimide compound of the present invention is applied to a part of a lens barrel and / or a base plate around the image pickup element between the image pickup lens and the image pickup element placed opposite to the image pickup lens. An imaging element has an electrode that is bonded to a circuit board. When there is a component that volatilizes or bleeds from a dust-proof resin, the electrode is corroded.
The shape of the lens barrel to which the composition containing the maleimide compound is applied is not limited. The material of the lens barrel is usually polyphenylene sulfide (PPS) or liquid crystal polymer (LCP), and a composition containing a maleimide compound is applied prior to assembling the module. The said composition can be apply | coated by a normal method, for example, can be apply | coated using a hot-melt gun, an inkjet, etc. The coating thickness is preferably 5 to 200 μm, and more preferably 10 to 100 μm. If the thickness is less than 5 μm, the dustproof property may be insufficient. On the other hand, if the thickness exceeds 200 μm, the active energy ray hardly reaches the deep part, and the object of the present invention may not be obtained.

After applying the composition containing the maleimide compound, the active energy rays are irradiated to crosslink the maleimide groups of the component (A) to increase the molecular weight, thereby improving the adhesive strength of the resulting cured coating film. The irradiation method of this active energy ray should just follow the method conventionally performed with active energy ray hardening-type resin. Examples of active energy rays include visible light, ultraviolet rays, X-rays, and electron beams, and it is preferable to use ultraviolet rays because inexpensive devices can be used. Examples of the light source in the case of using ultraviolet light include ultrahigh pressure, high pressure, medium pressure or low pressure mercury lamp, metal halide lamp, xenon lamp, electrodeless discharge lamp, and carbon arc lamp, and the irradiation may be performed for several seconds to several minutes. The integrated light amount of the active energy ray is preferably 200 to 3000 mJ / cm ² (365 nm). This is because sufficient curability can be obtained with an integrated light quantity in this range.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

○ Production Example 1
A flask equipped with a stirrer, a thermometer and a condenser was charged with 270 g of polyether polyol Adeka polyether P-3000 (polypropylene glycol, manufactured by Asahi Denka Kogyo Co., Ltd., hereinafter also referred to as “P-3000”) at room temperature, and stirred. The temperature was raised to 120 ° C. while dehydrating for 1 hour under reduced pressure. After dehydration, the mixture was cooled to 60 ° C. and charged with 40.4 g of isophorone diisocyanate (hereinafter also referred to as “IPDI”) and 0.050 g of di-n-butyltin dilaurate (hereinafter also referred to as “DBTL”) 2 Reacted for hours. Then, after heating up at 80 degreeC and continuing reaction for 30 minutes, 2-hydroxyethyl citrancimide [the compound of following formula (4). Hereinafter, “CM-ETA” was charged and reacted for 2 hours, and then the temperature was raised to 120 ° C. and degassed under reduced pressure for 1 hour to obtain a maleimide compound.
Furthermore, 0.1 g of “Elastostab H01” (trade name, manufactured by Elastgran), which is a carbodiimide compound as an acid mask agent, and pentaerythrityl tetrakis [3- (3,5-di-t-) as a phenol-based antioxidant. Butyl-4-hydroxyphenyl) propionate] 0.15 g was added to produce a composition containing a maleimide compound.

○ Production Examples 2-8
In Production Example 1, a composition containing a maleimide compound as Compound A was produced under the same conditions as in Production Example 1 except that the components and amounts shown in the following table were used. The numbers in parentheses in the table indicate the quantity charged (parts by mass) at the time of production. The evaluation method of the composition containing the obtained maleimide compound is as follows.

[viscosity]
Apparatus: Brookfield viscometer Temperature: 25 ° C
[Number average molecular weight]
Apparatus: HLC-8120 (manufactured by Tosoh Corporation)
Column: TSKgel-GMHxl x 2 (Tosoh Corporation)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran 1ml / min
Detector: RI
The molecular weight measured by GPC was converted based on the molecular weight of polystyrene.

The abbreviations in Table 1 mean the following.
1) P-3000: Polyether polyol having a number average molecular weight of 3000, manufactured by Asahi Denka Kogyo Co., Ltd., trade name “Adeka Polyether P-3000”
2) CM-381: Polyether polyol, manufactured by Asahi Denka Kogyo Co., Ltd., trade name “Adeka Polyether CM-381”
3) PES-1: polyester polyol, co-condensation product of 1,4-butanediol and adipic acid, number average molecular weight 5000
4) PES-2: Polyester polyol, co-condensation product of 3-methyl-1,5-pentanediol and adipic acid, number average molecular weight 5000
5) LBH-P5000: polybutadiene glycol having a number average molecular weight of 4800: Idemitsu Kosan Co., Ltd. trade name “KRASOL LBH-P5000”
6) P-1000: Polyether polyol having a number average molecular weight of 1000, manufactured by Asahi Denka Kogyo Co., Ltd., trade name “Adeka Polyether P-1000”
7) S-4011: Polyether polyol having a number average molecular weight of 10,000, manufactured by Asahi Glass Urethane Co., Ltd., trade name “PREMINOL S-4011”
8) PPG: polypropylene glycol, EO: ethylene oxide unit, PO: propylene oxide unit, 1,4BG: 1,4-butanediol, 3-MPD: 3-methyl-1,5-pentanediol 9) CM-ETA: 2 -Hydroxyethyl citraconimide alcohol 10) ML-ETA: 2-hydroxyethylmaleimide

○ Examples 1-6, Comparative Examples 1-2
After the composition containing the maleimide compound produced in the above production example and comparative example is applied to the base plate and the lens barrel portion around the CMOS sensor which is an image conversion element so as to have a thickness of about 50 μm, an ultraviolet irradiation device Using a 120 W / cm condensing type high-pressure mercury lamp, ultraviolet rays were applied from the coated surface side (integrated light amount = 1500 mJ / cm ² ) to produce a camera module coated with a dustproof resin.
The following evaluation was performed about the obtained camera module. The results are shown in Table 2.
○ Comparative Example 3
Acrylic solvent-type resin “Cooponyl 5560” (trade name, manufactured by Nihon Gosei Co., Ltd.) is applied to the base plate and lens barrel around the CMOS sensor, which is an image conversion element, so that the thickness after drying is about 50 μm. Then, it was dried at 40 ° C. for 30 minutes in a ventilation dryer to produce a camera module coated with a dustproof resin.
The following evaluation was performed about the obtained camera module. The results are shown in Table 3.
○ Comparative Example 4
“UC-1” (trade name, manufactured by Kuraray Co., Ltd.), an isoprene-based resin having a methacryloyl group, is applied to the base plate and the lens barrel around the CMOS sensor, which is an image conversion element, so that the thickness is about 50 μm. After that, using a UV irradiation device, a 120 W / cm condensing type high-pressure mercury lamp is used to irradiate UV light from the application surface side (integrated light quantity = 1500 mJ / cm ² ), and a camera module coated with a dustproof resin is obtained. Manufactured.
The following evaluation was performed about the obtained camera module. The results are shown in Table 3.

[Corrosive]
A camera module with a dust-proof resin applied to the ground plane and lens barrel around the CMOS sensor is manufactured and left in the following environment for 12 weeks. The presence or absence of corrosion of the electrode part of the CMOS sensor is checked with a 300x optical microscope. Observed. When there was no corrosion, “○” was indicated, and when there was corrosion, “X” was indicated. In addition, those that remain in a liquid state even when irradiated with a predetermined amount of ultraviolet rays were not cured.
Environmental conditions: temperature 60 ° C, humidity 95% RH, applied voltage 3V
[Dustproof]
A camera module in which a dust-proof resin was applied to the base plate and the lens barrel around the CMOS sensor was manufactured, left in the following environment for 6 weeks, and then touched with a finger to confirm the presence or absence of tackiness. Those having adhesiveness and maintaining a dustproof function were marked with “◯”, and those having no tackiness and without a dustproof function were marked with “X”.
Environmental conditions: temperature 60 ° C, humidity 95% RH

  The composition containing the maleimide compound of the present invention can be easily cured by irradiation with active energy rays to form a dustproof resin. In addition, the obtained dustproof resin can maintain dustproofness for a long period of time and does not cause corrosion inside the electronic component, so that it is useful for applications such as camera modules.

It is sectional drawing of an example of a camera module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Camera module, 2; Imaging lens, 3; Lens barrel, 4; Diaphragm, 5; Filter, 6; Opening part, 7: Ground plane of imaging device, 8: Imaging device (CCD, CMOS sensor, etc.), 9; Dust-proof resin, 10; circuit board.

Claims (6)

  A dustproof resin obtained by curing a composition containing a compound (A) having two or more maleimide groups having a number average molecular weight of 4000 to 20000 with active energy rays. The dustproof resin according to claim 1, wherein the compound (A) is a compound having two or more maleimide groups represented by the following formula (1).

[However, in Formula (1), R < ¹ > represents hydrogen, an alkyl group, an aryl group, an arylalkyl group, or a halogen atom. ] 3. The dustproof resin according to claim 2, wherein in the formula (1), R ¹ is a compound having two or more maleimide groups represented by hydrogen or an alkyl group having 4 or less carbon atoms.   The dustproof resin according to any one of claims 1 to 3, wherein the compound (A) is liquid at 25 ° C and has a polyether skeleton. An imaging lens, a lens barrel that holds the imaging lens, an imaging device that receives light incident from the imaging lens and generates a video signal, and a video signal output from the imaging device are input to perform signal processing A camera module with a circuit board to perform,
The dust-proof resin according to any one of claims 1 to 4 is applied to a portion other than the image pickup lens and the image pickup device between the image pickup device and the image pickup device that is installed facing the image pickup lens. A camera module characterized by   The camera module according to claim 5, wherein a portion other than the imaging lens and the imaging device is a ground plate disposed around the imaging device.

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