Active energy beam-curable resin composition, resin molding, and method for producing resin molding

Abstract

Provided are: a resin composition with which it is possible to form a cured film having excellent weather resistance and wear resistance; and a resin molding having said cured film. An active energy beam-curable resin composition containing a radical polymerizable compound and a photopolymerization initiator (d), wherein said radical polymerizable compound contains 57-90 mass % of (a) caprolactone-modified mono- or poly-penta erythritol poly (meth)acrylate represented by formula (1) and 10-43 mass % of (b) urethane (meth)acrylate synthesized from a polycarbonate polyol having a branched alkyl structure and an average molecular weight falling within the range of 500-1000, a diisocyanate having an alicyclic structure, and a mono (meth)acrylate containing a hydroxyl group. In formula (1), each X independently represents a caprolactone-modified (meth)acryloyl group, a (meth)acryloyloxy group, or a OH group. ##STR00001##

Claims

1. An active energy beam-curable resin composition comprising radical polymerizable compounds and (d) a photopolymerizable initiator, wherein the radical polymerizable compounds comprising, based on a total amount of 100% by mass of the radical polymerizable compounds, 71% to 90% by mass of (a) a caprolactone-modified mono- or poly-pentaerythritol poly(meth)acrylate represented by the following formula (1); and 10% to 29% by mass of (b) a urethane (meth)acrylate synthesized from a polycarbonate polyol having a branched alkyl structure and having a number average molecular weight in the range of 500 to 1,000, a diisocyanate having an alicyclic structure, and a mono(meth)acrylate containing a hydroxyl group: ##STR00003## wherein in formula (1), 4+2n units of X each independently represent a (meth)acryloyloxy group modified by caprolactone (CH.sub.2CRCO(O(CH.sub.2).sub.5CO).sub.yO), wherein R represents a hydrogen atom or a methyl group, and y represents an integer from 1 to 5; a (meth)acryloyloxy group (CH.sub.2CRCOO),wherein R represents a hydrogen atom or a methyl group; or a OH group; at least one X represents a (meth)acryloyloxy group modified by caprolactone, each of at least two Xs represents a (meth)acryloyloxy group, while each of the other Xs represents a OH group; and n represents an integer from 0 to 4% by mass or less of (c) a radical polymerizable monomer other than (a) and (b), the radical polymerizable monomer (c) being crystallizable at a temperature of 25 C.

2. The active energy beam-curable resin composition according to claim 1, wherein the active energy beam-curable resin composition further comprises (e) an ultraviolet absorber in an amount of 0.5 to 20 parts by mass relative to a total amount of 100 parts by mass of the radical polymerizable compounds.

3. The active energy beam-curable resin composition according to claim 1, wherein the active energy beam-curable resin composition further comprises (e) an ultraviolet absorber in an amount of 0.5 to 20 parts by mass relative to a total amount of 100 parts by mass of the radical polymerizable compounds.

4. The active energy beam-curable resin composition according to claim 2, wherein the (e) ultraviolet absorber has a molecular weight of 500 or more.

5. The active energy beam-curable resin composition according to claim 3, wherein the (e) ultraviolet absorber has a molecular weight of 500 or more.

6. The active energy beam-curable resin composition according to claim 2, wherein the (e) ultraviolet absorber is a combination of two or more kinds of ultraviolet absorbers each having a molecular weight of 500 or more.

7. The active energy beam-curable resin composition according to claim 3, wherein the (e) ultraviolet absorber is a combination of two or more kinds of ultraviolet absorbers each having a molecular weight of 500 or more.

8. The active energy beam-curable resin composition according to claim 1, wherein the active energy beam-curable resin composition further comprises (f) a hindered amine-based photostabilizer in an amount of 0.1 to 5 parts by mass relative to a total amount of 100 parts by mass of the radical polymerizable compounds.

9. A resin molded article having on a surface of the resin molded article, a cured film obtained by curing the active energy beam-curable resin composition according to claim 1.

10. A resin molded article having on a surface of the resin molded article, a cured film obtained by curing the active energy beam-curable resin composition according to claim 8.

11. The resin molded article according to claim 9, wherein the resin molded article is a headlamp lens for automotive use.

12. The resin molded article according to claim 10, wherein the resin molded article is a headlamp lens for automotive use.

13. A method for producing the resin molded article according to claim 9, the method comprising applying the active energy beam-curable resin composition on the surface of the resin molded article, and irradiating the coating film thus obtained with an active energy beam.

14. A method for producing the resin molded article according to claim 11, the method comprising applying the active energy beam-curable resin composition on the surface of a resin molded article, and irradiating a resultant coating film with an active energy beam.

15. A method for producing the resin molded article according to claim 10, the method comprising applying the active energy beam-curable resin composition on the surface of a resin molded article, and irradiating a resultant coating film with an active energy beam.

16. A method for producing the resin molded article according to claim 12, the method comprising applying the active energy beam-curable resin composition on the surface of a resin molded article, and irradiating a resultant coating film with an active energy beam.

Description

EXAMPLES

(1) Hereinafter, the present invention will be described in more detail by way of Examples and Comparative Examples. Measurement and evaluation in the Examples were carried out by the following methods.

(2) (1) Storage Stability

(3) An uncured resin composition was introduced into a shaded glass bottle, and the glass bottle was tightly sealed and stored in an environment at 20 C. for one month. Thereafter, the temperature of the resin composition was returned to room temperature, and the state of the resin composition was visually observed. A case in which none of foreign materials, whitening and clouding was observed in the resin composition, was rated as Good, and a case in which any one of these was observed was rated as Poor.

(4) (2) Abrasion Resistance

(5) For a resin molded article having a cured film formed on the surface, the haze values before and after an abrasion resistance test were measured using a haze meter (HM-65W, manufactured by Murakami Color Research Laboratory Co., Ltd.), and the increment of the haze value was determined. Regarding the abrasion test, a cured film was subjected to an abrasion test of 100 rotations according to JIS K7204 Testing method for abrasion resistance of plastics by abrasive wheels using a ROTARY ABRASION TESTER (manufactured by Toyo Seiki Kogyo Co., Ltd.), using abrasive wheels CS-10F under a load of 4.9 N (500 gf). Abrasion resistance was judged by the following criteria.

(6) Excellent: The increment of the haze value is 0% or more and less than 5%.

(7) Good: The increment of the haze value is 5% or more and less than 10%.

(8) Poor: The increment of the haze value is 10% or more.

(9) (3) Weather Resistance

(10) A resin molded article having a cured film formed on the surface was subjected to a weather resistance test for 4,000 hours using a SUNSHINE CARBON WEATHER-O-METER (manufactured by Suga Test Instmments Co., Ltd., WELSUN-HC-B type) weather resistance testing machine, under the conditions of a black panel temperature of 633 C., and a cycle of raining for 12 minutes and radiation for 48 minutes. Subsequently, the following evaluations (A) to (C) were carried out.

(11) (A) External Appearance

(12) After the weather resistance test, the external appearance of the cured film was visually observed. A case in which none of cracking, whitening, clouding and peeling of the cured film occurred in the cured film was rated as Good, and a case in which any one of these occurred was rated as Poor.

(13) (B) Transparency

(14) The haze values before and after the weather resistance test of the resin molded article were measured using a haze meter (HM-65W, manufactured by Murakami Color Research Laboratory Co., Ltd.), and the increment of the haze value was calculated and judged by the following criteria.

(15) Excellent: The increment of the haze value is 0% or more and less than 2.0%.

(16) Good: The increment of the haze value is 2.0% or more and less than 5.0%.

(17) Poor: The increment of the haze value is 5.0% or more.

(18) (C) Degree of Yellowing

(19) The Yellow Index (YI) values before and after the weather resistance test of the resin molded article were measured using an ultraviolet/visible spectrophotometer (trade name: Instantaneous Multi-channel Photometer MCPD-3000, manufactured by Otsuka Electronics Co., Ltd.), and the increment of the YI value was calculated. Meanwhile, the YI value was determined by measuring the tristimulus values (X, Y, Z), and calculating the value using the following expression.
YI value=100(1.28X1.06Z)/Y

(20) The increment of the YI value was judged by the following criteria:

(21) Excellent: The increment of the YI value is 0 or more and less than 1.0.

(22) Good: The increment of the YI value is 1.0 or more and less than 5.0.

(23) Poor: The increment of the YI value is 5.0 or more.

(24) (4) Heat Resistance

(25) A heat resistance test was performed by placing a resin molded article having a cured film formed on the surface, in a dryer at 120 C. for 480 hours. The resin molded article was taken out from the dryer, and then the cured film was visually observed. A case in which cracks were not observed was rated as Good, and a case in which cracks were observed was rated as Poor.

Synthesis Example 1

Synthesis of UA1

(26) Into a flask having a capacity of 5 liters and equipped with a dropping funnel having a function of thermal insulation, a reflux cooler, a stirring blade and a temperature sensor, 2 moles of dicyclohexylmethane-4,4-diisocyanate as a diisocyanate and 300 ppm of n-butyltin dilaurate were introduced, and the flask was warmed to 40 C. in a warm water bath. In a state in which the dropping funnel having a function of thermal insulation had been warmed to 40 C., 1 mole of a polycarbonate diol having a methylpentane structure (number average molecular weight 800, manufactured by Kuraray Co., Ltd., trade name: KURARAY POLYOL C770) as a diol was added dropwise into the flask over a period of 4 hours. The liquid inside the flask was stirred for 2 hours at 40 C., and the temperature was increased to 70 C. over a period of 1 hour. Subsequently, 2 moles of 2-hydroxyethyl acrylate as a mono(meth)acrylate containing a hydroxyl group was added dropwise into the flask over a period of 2 hours, and the liquid inside the flask was stirred for 2 hours. Thus, urethane acrylate UA1 (hereinafter, abbreviated to UA1) was synthesized.

Synthesis Example 2

Synthesis of UA2

(27) Urethane acrylate UA2 (hereinafter, abbreviated to UA2) was synthesized in the same manner as in Synthesis Example 1, except that 5 moles of dicyclohexylmethane-4,4-diisocyanate as a diisocyanate, 1 mole of N-methyl-N-(2-hydroxyethyl)-4-hydroxybutanamide and 1.5 moles of polytetramethylene glycol as diols, and 5.4 moles of 2-hydroxyethyl acrylate as a mono(meth)acrylate containing a hydroxyl group were used.

Example 1

(28) An active energy beam-curable resin composition was produced based on the mixing ratio indicated in Table 1. This resin composition was applied by bar coating on a polycarbonate resin plate (manufactured by Saudi Basic Industries Corporation (SABIC), trade name: LEXAN LS-II) having a dimension of 253 mm in length, 125 mm in width, and 3 mm in thickness, such that the thickness of the film after being cured would be 10 m. Subsequently, the resin plate having a coating film formed thereon was heat-treated at 60 C. for 3 minutes in an oven so as to volatilize the organic solvent. Subsequently, the coating film was irradiated with ultraviolet radiation having a wavelength of 340 nm to 380 nm using a high pressure mercury lamp at a cumulative amount of light of 3,000 mJ/cm.sup.2, the coating film was cured thereby, and thus a cured film was obtained.

(29) The resin molded article on which a cured film obtained in this manner was formed, was subjected to the various evaluations described above. The evaluation results are presented in Table 1. Furthermore, the numerical values in the columns for the resin composition in Table 1 and Table 2 indicate parts by mass. The abbreviations in Table 1 and Table 2 represent the compounds or marketed products indicated in Table 3.

Examples 2 to 10 and Comparative Examples 1 to 5

(30) Resin compositions were produced using the materials and mixing ratios indicated in Table 1 or Table 2, and resin molded articles having cured films formed thereon under the same conditions as in Example 1 were obtained. The evaluation results are presented in Table 1 and Table 2.

(31) TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 7 8 9 10 Resin Component (a) DPCA-20 71 71 71 60 60 80 70 85 71 60 composition Component (b) UA-1 29 29 24 40 35 20 10 15 29 10 Component (c) TAIC 0 0 5 0 5 0 0 0 0 30 Other component TMPTA 0 0 0 0 0 0 20 0 0 0 Component (d) BNP 1 1 1 1 1 1 1 1 1 1 MPG 1 1 1 1 1 1 1 1 1 1 BDK 1 1 1 1 1 1 1 1 1 1 Component (e) HBPB 0 0 0 0 0 0 0 0 10 0 HHBT 10 0 10 10 10 10 10 10 0 10 OHBT 0 10 0 0 0 0 0 0 0 0 Component (f) LA63 0 0 0 0 0.5 0.5 0 0 0 0 TINUVIN 123 0.5 0.5 0.5 0.5 0 0 0.5 0.5 0.5 0.5 Surface conditioning BYK-333 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 agent Diluent solvent PGM 179 179 179 179 179 179 179 179 179 179 ECA 6.7 6.7 6.7 6.7 6.7 6.7 6.7 6.7 6.7 6.7 Total 300.5 300.5 300.5 300.5 300.5 300.5 300.5 300.5 300.5 300.5 Evaluation (1) Storage stability Good Good Good Good Good Good Good Good Good Poor results (2) Abrasion resistance Excel- Excel- Excel- Good Good Excel- Excel- Excel- Excel- Excel- (increment of haze %) lent lent lent (5.8) (5.4) lent lent lent lent lent (3.6) (3.5) (2.5) (2.1) (1.8) (2.0) (3.4) (2.0) (3) Weather (A) External Good Good Good Good Good Good Good Good Good Good resistance appearance (B) Transparency Excel- Excel- Excel- Excel- Excel- Excel- Good Excel- Good Good (increment of lent lent lent lent lent lent (2.1) lent (2.2) (3.4) haze %) (1.1) (1.6) (1.8) (0.4) (0.7) (1.7) (1.9) (C) Degree of Excel- Excel- Excel- Excel- Excel- Excel- Excel- Excel- Good Good yellowing lent lent lent lent lent lent lent lent (2.0) (1.8) (increment of YI) (0.7) (0.6) (0.7) (0.5) (0.5) (0.7) (0.8) (0.8) (4) Heat resistance Good Good Good Good Good Good Good Good Good Good

(32) TABLE-US-00002 TABLE 2 Comparative Example 1 2 3 4 5 6 Resin composition Component (a) DPCA-20 95 40 40 90 71 55 Component (b) UA-1 5 40 60 5 0 35 Component (c) TAIC 0 0 0 5 0 10 Other component UA-2 0 0 0 0 29 0 TMPTA 0 20 0 0 0 0 Component (d) BNP 1 1 1 1 1 1 MPG 1 1 1 1 1 1 BDK 1 1 1 1 1 1 Component (e) HHBT 10 10 10 10 10 10 OHBT 0 0 0 0 0 0 Component (f) LA63 0 0 0 0 0 0 TINUVIN 123 0.5 0.5 0.5 0.5 0.5 0.5 Surface conditioning BYK-333 1.3 1.3 1.3 1.3 1.3 1.3 agent Diluent solvent PGM 179 179 179 179 179 179 ECA 6.7 6.7 6.7 6.7 6.7 6.7 Total 300.5 300.5 300.5 300.5 300.5 300.5 Evaluation results (1) Storage stability Good Good Good Good Poor Poor (2) Abrasion resistance (increment of haze %) Excellent Poor Poor Excellent Good Good (1.6) (10.2) (12.1) (1.4) (5.1) (9.2) (3) Weather (A) External appearance Poor Good Good Poor Poor Poor resistance (B) Transparency Poor Excellent Excellent Poor Good Excellent (increment of haze %) (8.9) (0.6) (0.4) (7.2) (3.1) (1.2) (C) Degree of yellowing Poor Excellent Excellent Poor Good Excellent (increment of YI) (5.1) (0.5) (0.5) (5.2) (1.8) (0.8) (4) Heat resistance Poor Good Good Poor Good Good

(33) TABLE-US-00003 TABLE 3 Abbre- viation Compound or trade name DPCA-20 Dipentaerythritol hexaacrylate modified by two caprolactone molecules per molecule (manufactured by Nippon Kayaku Co., Ltd., trade name: KAYARAD DPCA20) UA-1 Urethane acrylate synthesized in Synthesis Example 1 UA-2 Urethane acrylate synthesized in Synthesis Example 2 TAIC Tris(2-acryloyloxyethyl) isocyanurate TMPTA Trimethylolpropane triacrylate BNP Benzophenone MPG Methylphenyl glyoxylate BDK Benzyl dimethyl ketal HBPB 2-(2-Hydroxy-5-tert-butylphenyl)benzotriazole (molecular weight 267) HHBT Mixture (molecular weight 647) of 2-[4-(2-hydroxy-3- dodecyloxypropyl) oxy-2-hydroxyphenyl]-4,6-[bis(2.4- dimethylphenyl)-1,3,5-triazine (molecular weight 640) (about 47%) and 2-[4-(2-hydroxy-3-tridecyloxypropyl)oxy- 2-hydroxyphenyl]-4,6-[bis(2,4-dimethylphenyl)-1,3,5- triazine (molecular weight 653) (about 53%) {trade name: TINUVIN 400 (BASF)} OHBT 2-[4-(Octyl-2-methylethanoate)oxy-2-hydroxyphenyl]- 4,6-[bis(2,4-dimethylphenyl)-1,3,5-triazine [trade name: TINUVIN 479 (BASF)] (molecular weight 677) LA63 Trade name: ADEKASTAB LA-63P (ADEKA Corp.) TINUVIN Reaction product between decanedicarboxylic acid, a diester 123 compound of 2,2,6,6-tetramethyl-1-octooxy-4-piperidinol, 1,1-dimethylethyl hydroperoxide, and octane {trade name: TINUVIN 123 (BASF)} BYK-333 Silicon-based leveling agent (manufactured by BYK Chemie Japan, K.K., trade name: BYK-333) PGM 1-Methoxy-2-propanol ECA Ethylcarbitol acetate

(34) [Summary of Evaluation Results]

(35) As shown in Table 1, since the resin compositions of Examples 1 to 9 have the mixing ratios of the components (a) to (c) in a predetermined range, the various evaluation results were satisfactory. The resin composition of Example 10 exhibited satisfactory abrasion resistance, weather resistance and heat resistance; however, since the content of the component (c) was large, storage stability of the coating material was poor.

(36) As shown in Table 2, in the resin composition of Comparative Example 1, since the content of the component (a) was too large and the content of the component (b) was too small, weather resistance of the cured film was poor. In the resin composition of Comparative Example 2 and Comparative Example 3, since the content of the component (a) was too small, abrasion resistance of the cured films was poor. In the resin composition of Comparative Example 4, since the content of the component (b) was too small, weather resistance of the cured film was poor. Since the resin composition of Comparative Example 5 did not contain the component (b) but contained a urethane acrylate that did not correspond to the component (b) as a urethane (meth)acrylate, storage stability of the coating material was poor, and weather resistance of the cured film was also poor.

INDUSTRIAL APPLICABILITY

(37) A cured film obtainable from the resin composition of the present invention is effective for enhancing the weather resistance and abrasion resistance of resin molded articles such as various lamp lenses, glazings, and covers for gauges for automotive use.