JP6697900B2 - Reactive hot melt composition for automobile lighting and automobile lighting - Google Patents

Description

  The present invention relates to a reactive hot-melt composition for an automotive lamp and a housing part of the composition, which is used for adhering a housing part constituting a lamp part of an automobile and a lens part made of a polycarbonate resin or the like covering the front surface thereof. The present invention relates to a vehicle lighting device in which a lens portion is bonded.

  Conventionally, the housing part and the lens part that covers the front surface of the lamp part of the automobile have large mechanical strength such as impact strength, are stable to heat, and are excellent in weather resistance and transparency. Polycarbonate resin is widely used. Examples of the reactive hot melt adhesive used for bonding the polycarbonate resin lens part and the housing part include a polyol containing a crystalline aliphatic polyester diol (a1) and an aliphatic polyether polyol (a2). (A) and an isocyanate group-terminated urethane prepolymer (A) obtained by reacting polyisocyanate (b), a morpholine ring-containing compound (B) and a compound (C) having a carboxyl group. A reactive hot melt adhesive is proposed (Patent Document 1).

JP, 2009-286883, A

  However, when the reactive hot melt adhesive is used for bonding a housing part that constitutes a lamp part of an automobile and a lens part made of polycarbonate resin or the like covering the front surface, the inner surface of the lens made of polycarbonate resin or the like is There is a problem that a fogging phenomenon may occur in which the cloudiness is white and transparency is lowered as a whole.

  In particular, this problem has been a problem that cannot be solved for many years because it is difficult to identify the causative substance because there are many types of chemical materials that compose the reactive hot melt adhesive. The inventor of the present application, as a result of intensive research to solve the problem, has clarified the cause of the above-mentioned fogging phenomenon, and completed the present invention.

  The problem to be solved by the present invention is that even when used for bonding a housing part that constitutes a lamp part of an automobile and a lens part made of polycarbonate resin or the like that covers the front surface, the inside surface of the polycarbonate resin cover is white. It is an object of the present invention to provide a reactive hot melt composition for an automobile lamp and an automobile lamp which are free from the fog phenomenon in which transparency is lowered as a whole due to clouding.

In order to solve the above problems, the invention according to claim 1 of the present application comprises a polyisocyanate, a polyester polyol, a polyether polyol, and at least one of an acrylic polyol and an acrylic resin, and the acrylic polyol and the acrylic resin are An automotive lamp characterized in that an acrylic monomer is polymerized with a polymerization initiator which is 2,2'-azobis(isobutyric acid) dimethyl and a chain transfer agent having a molecular weight of 200 to 1000, and a weight average molecular weight thereof is 15000 to 60,000. A reactive hot melt composition for use is provided.

The invention according to claim 2 provides the reactive hot melt composition for automobile lighting according to claim 1 , wherein the chain transfer agent is a mercapto group-containing compound .

  The invention according to claim 3 provides the reactive hot melt composition for automobile lighting according to claim 1 or 2, wherein the acrylic polyol has a hydroxyl value of 2 to 20 mgKOH/g.

  In the invention according to claim 4, the acrylic polyol is polymerized by using at least one of methyl methacrylate (MMA), butyl methacrylate (BMA) or 2-hydroxyethyl methacrylate (2-HEMA) as a monomer component, and an acrylic resin. Is polymerized by using at least either methyl methacrylate (MMA) or butyl methacrylate (BMA) as a monomer component, and the reactive hot for automobile lighting according to any one of claims 1 to 3. A melt composition is provided.

The invention according to claim 5 is characterized in that the weight ratio of the polyester polyol and the acrylic polyol or the acrylic resin is 10/100 to 100/10, and the automobile according to any one of claims 1 to 4. Provided is a reactive hot melt composition for a lamp.

The invention according to claim 6 is characterized in that the weight ratio of the polyester polyol and the polyether polyol is from 10/100 to 100/10, and the automotive lighting device according to any one of claims 1 to 5. A reactive hot melt composition is provided.

  Further, an invention according to claim 7 is an automotive lamp characterized in that the lens part and the housing part are adhered with the reactive hot melt composition for automotive lamp according to any one of claims 1 to 6. provide.

  The reactive hot melt composition for a vehicle lighting device according to the present invention causes the above-mentioned fogging phenomenon even when used for bonding a housing part constituting a lighting part of a vehicle and a lens part made of a polycarbonate resin or the like covering the front surface thereof. The effect is that there is nothing to do.

  Further, the reactive hot melt composition for an automobile lamp according to the present invention has an effect that it is excellent in coating property because of its low viscosity and has good initial adhesiveness.

  Further, the housing part constituting the lamp part of the automobile with the reactive hot melt composition for an automotive lamp according to the present invention, and the automotive lamp to which the lens part made of a polycarbonate resin or the like covering the front surface thereof is adhered has the same fogging phenomenon as described above. The effect is that it does not occur.

  BEST MODE FOR CARRYING OUT THE INVENTION The reactive hot melt composition for an automobile lamp and the automobile lamp of the present invention will be described in detail below.

The reactive hot melt composition for automobile lighting of the present invention comprises a polyisocyanate, a polyester polyol, a polyether polyol, and at least one of an acrylic polyol and an acrylic resin, and the acrylic polyol and the acrylic resin each contain an acrylic monomer of 70% or less. A reactive hot melt composition for automobile lighting, which is polymerized with an azo polymerization initiator having an azo decomposition product evaporation rate of 20 to 100 mg/hr·cm ² and a chain transfer agent having a molecular weight of 200 to 1000, and if necessary. , Antioxidants, ultraviolet absorbers, light stabilizers, other tackifiers, colorants, pigments, fillers, defoamers, foam inhibitors, catalysts and the like can be added.

Polyisocyanate The polyisocyanate used in the present invention is a polyisocyanate having two or more functional groups, which is C (except carbon in NCO group, the same applies hereinafter) 6 to 20 aromatic polyisocyanate, C2 to 18 aliphatic polyisocyanate. Isocyanates, C4-15 alicyclic ring-containing polyisocyanates, C8-15 araliphatic polyisocyanates, or modified products of these polyisocyanates and mixtures of two or more thereof can be used.

  Aromatic polyisocyanates include diisocyanates [1,3- and/or 1,4-phenylene diisocyanate, 2,4- and/or 2,6-tolylene diisocyanate (TDI), 2,4′- and/or 4 ,4'-diphenylmethane diisocyanate (MDI), 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-di Isocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, m- and p-isocyanatophenylsulfonyl isocyanate, etc.] Trifunctional or higher polyisocyanate [4,4',4"-triphenylmethane triisocyanate, crude TDI, crude MDI, etc.] and the like.

  Examples of the aliphatic polyisocyanate include diisocyanate [ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylcaproic acid. Ate, bis(2-isocyanatoethyl)fumarate, bis(2-isocyanatoethyl)carbonate, etc.], triisocyanate [2-isocyanatoethyl-2,6-diisocyanatohexanoate, 1,6,11 —Undecane triisocyanate, etc.” and the like.

  Examples of the alicyclic ring-containing polyisocyanate include diisocyanate [isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4′-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis(2-isocyanate). Natoethyl)-4-cyclohexene-1,2-dicarboxylate, 2,5- and/or 2,6-norbornane diisocyanate and the like], triisocyanate [bicycloheptane triisocyanate and the like] and the like.

  Examples of the araliphatic polyisocyanate include diisocyanate [m- and/or p-xylylene diisocyanate (XDI), α,α,α',α'-tetramethylxylylene diisocyanate (TMXDI), etc.]. ..

  As the modified polyisocyanate, modified (urethane modified, carbodiimide modified, trihydrocarbyl phosphate modified, etc.) MDI, urethane modified TDI, biuret modified HDI, isocyanurate modified HDI, isocyanurate modified IPDI, etc. , And a mixture of two or more thereof [for example, combined use of modified MDI and urethane modified TDI (isocyanate group-containing prepolymer)].

  Among the above polyisocyanates, HDI, IPDI, TDI, MDI, XDI, TMXDI, hydrogenated MDI and hydrogenated TDI are preferable in terms of adhesiveness, and HDI, MDI and a mixture thereof are more preferable.

Polyester Polyol As the polyester polyol used in the present invention, those formed by condensation of an aliphatic dihydric alcohol and an aliphatic (saturated or unsaturated) dicarboxylic acid can be used.

  As the aliphatic dihydric alcohol, {carbon number (hereinafter abbreviated as C) 2 to 20, for example, aliphatic [ethylene glycol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,2-, 1,3- And 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,3-, 1,4-, 1,6- and 2,5-hexanediol, 1,2- and 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,18-octadecanediol, 1,20-eicosanediol, etc.], alkyl (C1-3) dialkanolamine etc.} can be mentioned. Of these, 1,4-butanediol, 1,6-hexanediol, and 1,9-nonanediol are preferable in terms of adhesiveness.

  As the aliphatic dicarboxylic acid, as a saturated aliphatic dicarboxylic acid, C2-24, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, methylsuccinic acid, dimethylmalonic acid, β-methylglutaric acid, ethylsuccinic acid, isopropylmalonic acid , Adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, tridecanedicarboxylic acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, octadecanedicarboxylic acid and eicosandicarboxylic acid As the unsaturated aliphatic dicarboxylic acid, mention may be made of C4-24, such as maleic acid, fumaric acid, citraconic acid and mesaconic acid. Of these, adipic acid and sebacic acid are preferable in terms of adhesiveness and crystallinity.

Polyether Polyol The polyether polyol used in the present invention is preferably an aliphatic polyether polyol, and examples thereof include those obtained by adding alkylene oxide to water or alcohol, such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. I can.

  The weight ratio of polyester polyol to acrylic polyol or acrylic resin is preferably from 10/100 to 100/10, and when it is less than 10/100, the viscosity is high and workability tends to be poor, and when it exceeds 100/10, the strength tends to be lowered. . It is more preferably 10/100 to 100/100, and if it is less than 10/100, the viscosity tends to increase, and if it exceeds 100/100, the strength tends to decrease.

  The weight ratio of the polyester polyol and the polyether polyol is preferably from 10/100 to 100/10, and when the ratio is less than 10/100, the strength decreases, and when it exceeds 100/10, the viscosity increases. It is more preferably 10/100 to 100/100, and if it is less than 10/100, the strength tends to decrease, and if it exceeds 100/100, the strength tends to decrease.

  The reactive hot melt composition for automobile lighting of the present invention comprises a terminal isocyanate urethane prepolymer obtained by reacting an excess polyisocyanate with a polyester polyol, an acrylic polyol, and a polyether polyol as constituent components. The equivalent ratio of the isocyanate group to the hydroxyl group in the urethanization reaction of polyisocyanate and these polyols is preferably 1/1 to 2/1 from the viewpoint of adhesiveness and melt viscosity, and 1.3/1 to 1.7/1. More preferable.

  The excess polyisocyanate is reacted with the polyester polyol, acrylic polyol, and polyether polyol by first thoroughly mixing the polyester polyol, acrylic polyol, and polyether polyol, and then reacting the mixture with polyisocyanate.

Acrylic Polyol The acrylic polyol and the acrylic resin used in the present invention include an azo polymerization initiator having an azo decomposition product evaporation rate of 70 to 100° C. of 20 to 100 mg/hr·cm ² , and a chain transfer agent having a molecular weight of 200 to 1000. An acrylic polyol or an acrylic resin polymerized by. The evaporation rate (dM/dt) of the azo decomposition product is uniform with 10 mg of the azo polymerization initiator in the measuring cell SUS (5 mmφ×5 mm: bottom area: 0.196 cm ² ) of TG-DTA (differential thermal/thermogravimetric simultaneous measurement device). The weight change (mg/hr·cm ² : dM/dt) at a heating rate of 10° C./hr, and after obtaining the evaporation rate equation by the following equation (linear regression (least squares method ), the slope B and the intercept A are calculated), and 70° C. (absolute temperature K343° C.) is substituted into the obtained evaporation rate formula.
Evaporation rate formula: log(dM/dt)=A−B/T A, B: coefficient, T: absolute temperature (K)

  The weight average molecular weight of the acrylic polyol and the acrylic resin polymerized by the azo polymerization initiator and the chain transfer agent having a molecular weight of 200 to 1000 is 15,000 to 60,000, and more preferably 15,000 to 40,000 by the GPC method. If the weight average molecular weight is less than 15,000, fogging may occur, and if it exceeds 60,000, the viscosity of the composition becomes high and the coating workability becomes poor. If it exceeds 40,000, the coating workability tends to be poor.

  The acrylic polyol is a copolymer or the like of (meth)acrylic acid [alkyl (C1-30)] ester [methyl (meth)acrylate] and a hydroxyl group-containing acrylic monomer [hydroxyethyl (meth)acrylate], Preferably, at least one of methyl methacrylate (MMA) or butyl methacrylate (BMA) or 2-hydroxyethyl methacrylate (2-HEMA) is polymerized as a monomer component. The hydroxyl value is preferably 2 to 20 mgKOH/g. If it is less than 2 mgKOH/g, the adhesive strength may be insufficient, and if it exceeds 20 mgKOH/g, the cured product may become too hard. The acrylic resin is used for imparting tackiness, and at least a (co)polymer such as alkyl or alkenyl (meth)acrylate and acrylic acid can be used, and preferably at least methyl methacrylate (MMA). Alternatively, butyl methacrylate (BMA) is used as a monomer component for polymerization.

Azo polymerization initiators, azo decomposition products evaporation rate of preferably 20~100mg / hr · cm ^2, occurs fogging is less than 20mg / hr · cm ^2, the workability during the polymerization at 100mg / hr · cm ² greater Becomes defective. As a polymerization initiator having an azo decomposition product evaporation rate of 20 to 100 mg/hr·cm ² , there is 2,2′-azobis(isobutyric acid) dimethyl (azo decomposition product evaporation rate: 25 mg/hr·cm ² ).

  Further, the chain transfer agent used in the polymerization preferably has a molecular weight of 200 to 1000. If the molecular weight is less than 200, fogging occurs, and if it exceeds 1000, workability during polymerization becomes poor. As a chain transfer agent having a molecular weight of 200 to 1000, there is pentaerythritol tetrakis(3-mercaptopropionate) (molecular weight 488).

  The automotive lamp according to claim 7 is a reactive hot melt composition for an automotive lamp according to any one of claims 1 to 6, which is made of the above material, and is used as a lens portion such as a headlamp or a rear lamp of an automobile. It is an automobile lamp in which a housing portion supporting the same is adhered.

  Hereinafter, the reactive hot melt composition for automobile lighting according to the present application will be specifically described in Examples and Comparative Examples.

Examples and Comparative Examples MIO as a polyisocyanate, Millionate MT (trade name, manufactured by Tosoh Corporation, NCO weight%: 33.6 weight %), as polyester polyol, HS 2H-451A (trade name, manufactured by Toyokuni Oil Co., Ltd., adipine) Crystal polyester polyester obtained by esterification reaction of acid with 1,6 hexanediol, molecular weight: 4500) is used as polyether polyol, Adeka Polyether P-2000 (trade name, manufactured by Adeka, molecular weight: 2000) did. As the acrylic resin and the acrylic polyol, acrylic resin A, acrylic resin B, acrylic resin C, acrylic resin D, acrylic resin E, acrylic polyol A, and acrylic polyol B prepared by the following procedures were used. In the formulation shown in 2, the materials other than polyisocyanate were put into a separable flask equipped with a stirrer, a temperature controller, and a vacuum pump, stirred at 120° C. under reduced pressure for 2 hours for dehydration, and then polyisocyanate In addition, the mixture was stirred and reacted at 110° C. under a nitrogen atmosphere for 2 hours to obtain a reactive hot melt composition for automobile lighting of Examples and Comparative Examples which was solid at room temperature.

<Acrylic resin A>
Methyl methacrylate 70.32 parts by weight, n-butyl methacrylate 29 parts by weight, methacrylic acid 0.68 parts, 2,2'-azobis(isobutyric acid) dimethyl as a polymerization initiator (azo decomposition product evaporation rate: 25 mg/hr Cm ² ) 5 parts by weight and ² parts by weight of pentaerythritol tetrakis(3-mercaptopropionate) (molecular weight 488) as a chain transfer agent are mixed and dissolved to prepare a monomer solution. Next, in a separable flask equipped with a stirrer and a reflux condenser, 190 parts by weight of water, anion surfactant PRYSERB A210G (trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., polyoxyethylene phosphate ester-based surfactant) 0.01 parts by weight and 50 parts by weight of a 10% by weight tribasic calcium phosphate slurry as a dispersant for suspension polymerization are added and mixed uniformly. Next, the above monomer solution is added and the monomer is dispersed with a stirrer. While checking the particle size with a microscope, increase the stirring speed and when the desired particle size is reached, lower the stirring speed and start heating. After reacting at 70° C. for 2 hours and confirming that the heat generated by the polymerization has subsided, the mixture is further heated at 85° C. for 3 hours to complete the polymerization. After completion of the polymerization, the mixture is cooled to 40° C., 10 parts of concentrated hydrochloric acid is added to dissolve tricalcium phosphate. After dehydration and taking out the particles, the particles were dried at 70° C. for 12 hours to obtain a particulate acrylic resin A. The obtained acrylic resin A had a weight average molecular weight of 32,000 and a weight average molecular weight/number average molecular weight of 1.6 according to the GPC method.

<Acrylic resin B>
A particulate acrylic resin B was obtained in the same manner as in the polymerization of acrylic resin A except that thiosalicylic acid (molecular weight 154) was used in place of the chain transfer agent used in the polymerization of acrylic resin A. The obtained acrylic resin B had a weight average molecular weight of 35,000 by GPC method and a weight average molecular weight/number average molecular weight of 1.6.

<Acrylic resin C>
A particulate acrylic resin C obtained in the same manner as the polymerization of acrylic resin A was used, except that benzoyl peroxide was used instead of the polymerization initiator used in the polymerization of acrylic resin A. The weight average molecular weight of the obtained acrylic resin C by the GPC method was 35,000, and the weight average molecular weight/number average molecular weight was 1.6.

<Acrylic resin D>
Similar to the polymerization of acrylic resin A except that 1.7 parts by weight of tetraethylene glycol bis(3-mercaptopropionate) (molecular weight 372) was used in place of the chain transfer agent used in the polymerization of acrylic resin A. A particulate acrylic resin D obtained in the above was obtained. The acrylic resin D obtained by the GPC method had a weight average molecular weight of 28,000 and a weight average molecular weight/number average molecular weight of 1.6.

<Acrylic resin E>
In the same manner as in the polymerization of acrylic resin A, except that 1.3 parts by weight of 2-ethylhexyl-3-mercaptopropionate (molecular weight 218) was used in place of the chain transfer agent used in the polymerization of acrylic resin A. The obtained particulate acrylic resin E was obtained. The weight average molecular weight of the obtained acrylic resin E by the GPC method was 26000, and the weight average molecular weight/number average molecular weight was 1.9.

<Acrylic polyol A>
Methyl methacrylate 68.25 parts by weight, n-butyl methacrylate 27.9 parts by weight, 2-hydroxyethyl methacrylate (2-HEMA) 2.55 parts by weight, 2,2'-azobis(isobutyric acid) as a polymerization initiator 5 parts by weight of dimethyl (azo decomposition product evaporation rate: 25 mg/hr·cm ² ) and ² parts by weight of pentaerythritol tetrakis(3-mercaptopropionate) (molecular weight 488) as a chain transfer agent were mixed and dissolved to prepare a monomer solution. To do. Then, after reacting in the same manner as the acrylic resin A, it was dried at 60° C. for 12 hours to obtain a particulate acrylic polyol A. The weight average molecular weight of the obtained acrylic polyol A by GPC method was 26000, and the weight average molecular weight/number average molecular weight was 1.5.

<Acrylic polyol B>
A particulate acrylic polyol B was obtained in the same manner as in the polymerization of acrylic polyol A except that thiosalicylic acid (molecular weight 154) was used instead of the chain transfer agent used in the polymerization of acrylic polyol A. The weight average molecular weight of the obtained acrylic polyol B by the GPC method was 28,000, and the weight average molecular weight/number average molecular weight was 1.6.

Evaluation items and evaluation methods Evaluation items and evaluation methods are shown below.

Viscosity Using a Brookfield viscometer, 15 g of the reactive hot melt composition for automobile lighting of Examples or Comparative Examples was melted to 120° C., measurement temperature: 120±1° C., spindle No. 29, rotation speed at the time of measurement The viscosity (Pa·s) immediately after holding for 30 minutes at 10 rpm was measured.

Initial adhesiveness has a groove opened on the upper side, and the groove width of the opening is 5 mm, the depth is 20 mm, and the groove of the U-shaped surface-treated polypropylene prepreg jig in front view, The reactive hot melt composition for automobile lighting of Examples or Comparative Examples was heated to 120° C. and filled, and immediately, a polycarbonate flat plate having a thickness of 2 mm, a depth of 20 mm and a height of 50 mm was placed in the center of the groove in a front view. Insert parallel to the groove until it touches the bottom of the groove more. At the time of insertion, the hot melt composition protruding from the groove is carefully removed. Then, it was aged at 23° C. for 168 hours, and the inserted polycarbonate flat plate was pulled out upward at 50° C./sec at 23° C. or 90° C., and the tensile strength (N) at that time was measured. At 23° C., 900 N or more was evaluated as ◯, and less than 900 N was evaluated as x. At 90°C, 100N or more was evaluated as ◯, and less than 100N was evaluated as x.

Fogging Property The reactive hot melt composition for automobile lighting of the example or the comparative example is heated to 120° C. to prepare a sheet having a thickness of 2 mm and a diameter of 80 mm and aged at 23° C. and 50% RH for 7 days. The sheet is placed in a flask and the mouth of the flask is sealed with a perforated glass plate. Next, the hole of the glass is sealed with a polycarbonate plate having a thickness of 3 mm. Further, the lower part of the flask is heated at 120° C. for 24 hours, and the presence or absence of volatile substances adhering to the polycarbonate plate is visually confirmed. The case where there was no adhesion was evaluated as ◯, and the case where other solid and liquid materials were adhered was evaluated as x.

  The evaluation results are shown in Tables 3 and 4.

Claims (7)

Polyisocyanate, polyester polyol, polyether polyol, and at least one of acrylic polyol and acrylic resin. The acrylic polyol and acrylic resin are acrylic monomers 2,2'-azobis(isobutyric acid) dimethyl. And a chain transfer agent having a molecular weight of 200 to 1000, and having a weight average molecular weight of 15,000 to 60,000 . The reactive hot melt composition for automobile lighting according to claim 1 , wherein the chain transfer agent is a mercapto group-containing compound .   The acrylic polyol has a hydroxyl value of 2 to 20 mgKOH/g, and the reactive hot melt composition for automobile lighting according to claim 1 or 2. Acrylic polyol is polymerized with at least one of methyl methacrylate (MMA) or butyl methacrylate (BMA) or 2-hydroxyethyl methacrylate (2-HEMA) as a monomer component, and the acrylic resin is at least methyl methacrylate (MMA) or The reactive hot melt composition for automobile lighting according to any one of claims 1 to 3, which is polymerized with any of butyl methacrylate (BMA) as a monomer component. The reactive hot melt composition for automobile lighting according to any one of claims 1 to 4, wherein a weight ratio of the polyester polyol and the acrylic polyol or the acrylic resin is 10/100 to 100/10 . The reactive hot melt composition for automobile lighting according to any one of claims 1 to 5, wherein the weight ratio of the polyester polyol and the polyether polyol is 10/100 to 100/10 .   An automotive lamp comprising the reactive hot melt composition for an automotive lamp according to any one of claims 1 to 6, wherein a lens part and a housing part are adhered to each other.