JP3100440B2 - Composite polycarbonate molded article having excellent surface properties and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aromatic polycarbonate molded article complexed with an ultraviolet-curable polyacrylate composition and a method for producing the same. Since the surface of the molded product has a coating having high hardness and excellent scratch resistance, adhesion, and weather resistance, and the molded product has good surface characteristics, it can be applied to various uses.

[0002]

2. Description of the Related Art Aromatic polycarbonate has various characteristics such as transparency and light weight, excellent mechanical properties, and easy workability. Used as
It is well known that it is used for various purposes.

[0003] However, compared to metals and glasses, the surface hardness, abrasion resistance, abrasion resistance, solvent resistance, and other various surface characteristics are inferior, and thus their use is restricted. Therefore, there is a strong demand for improving the surface characteristics of an aromatic polycarbonate molded article.

[0004] In order to improve the surface characteristics of an aromatic polycarbonate molded article, various attempts to form a protective film by applying a paint to the surface of the molded article have been conventionally proposed.

[0005] For example, a method of applying a thermosetting melamine resin paint and forming a protective film by thermosetting (Japanese Patent Laid-Open No.
7-33164, 48-80175 and 51-111276) or a method of applying a hydrolysis product of an organosiloxane compound and forming a protective film made of an organosiloxane by thermosetting (particularly). JP-A-52-138565, JP-A-60-252633
No., etc.).

However, these methods of forming a protective film by heat curing require the treatment of the molded article under severe conditions of high temperature and long time for curing, and this treatment makes the aromatic polycarbonate molded article excellent in its original properties. The danger of damaging the mechanical properties is increased.

[0007] Furthermore, there are problems in the adhesion between the polycarbonate substrate and the protective film and the durability of the protective film itself.

On the other hand, as an alternative to heat curing, there is also a method of forming a synthetic resin protective film by using a polyfunctional acrylate compound as a coating material and irradiating it with an energy ray such as an ultraviolet ray or an electron beam to convert it into a cured resin. Proposals have been made (for example, JP-A-53-7771; JP-B-49-14859; JP-B-52-47663).
JP-A-58-101120).

Although the method proposed here has the advantage that curing is completed in a short time, the adhesion between the polycarbonate substrate and the protective film is not satisfactory, and the durability of the coating film, especially the weather resistance, Insufficient adhesion, poor adhesion and deterioration of abrasion resistance are also observed.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to improve the disadvantages of the prior art, improve the scratch resistance, hardness and weather resistance of the polycarbonate surface, and further improve the adhesion between the surface protective film and the substrate. It is an object of the present invention to provide a composite polycarbonate molded article having excellent heat resistance and a method for producing the same.

[0011]

SUMMARY OF THE INVENTION The present invention provides a composite polycarbonate molding having excellent surface characteristics, characterized in that an ultraviolet curing film of the following polyvalent acrylate composition is provided on the surface of an aromatic polycarbonate molding. Goods. Epoxy acrylate resin having the structure of formula I

[0012]

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(Wherein R represents H or a lower alkyl group, R 'represents H or CH _3, and n is an integer of 0 to 20) in an amount of 1 to 60% by weight of the whole polyhydric acrylate compound. Polyvalent acrylate composition.

Further, the method for producing a composite polycarbonate molded article as described above, wherein the epoxy acrylate resin having the structure of the formula I is formed on the surface of the aromatic polycarbonate molded article.

[0015]

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(Wherein R represents H or a lower alkyl group, R 'represents H or CH ₃ , where n is an integer of 0 to 20) in an amount of 1 to 60% by weight of the whole polyhydric acrylate compound. After applying the polyvalent acrylate composition, the ultraviolet light is irradiated to cure the polyvalent acrylate composition,
A manufacturing method characterized by forming a protective film.

Furthermore, 1 to the polyvalent acrylate composition
It contains 10 to 10% by weight of a sensitizer.

In the present invention, in the polyhydric acrylate composition applied to the surface of the aromatic polycarbonate molded article, the molecular weight and the compounding ratio of the compound of the above formula I greatly affect the workability.

That is, if n in the above formula I is too large, the viscosity of the solution becomes extremely high, the workability of coating is deteriorated, and it is difficult to obtain a smooth film, so n is 0 to 20, preferably 0. ~ 15 is good.

The epoxy acrylate resin used in the present invention is synthesized from the epoxy resin of the following formula II.

[0021]

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(Wherein n is the same as in the case of formula I). This is the same as in a conventional method for synthesizing a known epoxy resin.

[0023]

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The compound can be synthesized by ring-opening polymerization of epichlorohydrin using a basic catalyst, and the number of n can be controlled by changing the charging ratio to obtain the target substance. Note that n
The number can be identified by GPC measurement.

A characteristic of this resin is that since it has a large molecular weight per acrylate functional group, it has a small curing shrinkage and does not warp when coated on a thin material such as a plastic sheet.

Although the conventional polyfunctional acrylate has a high degree of crosslinking, it has a large shrinkage upon curing and is unsuitable for single coating on a thin sheet-like substrate.

However, in the present invention, by appropriately blending the above epoxy acrylate resin, curing shrinkage becomes extremely small, and warpage can be eliminated while increasing surface hardness and adhesion.

As the polyvalent acrylate composition of the present invention,
Examples of the polyhydric acrylate compound which can be used in combination with the epoxy acrylate resin having the structure of the above-mentioned formula I include polyhydric alcohol (or polyhydric phenol) (meth)
Acrylic esters that can be cured by ultraviolet rays, preferably (meth) acrylic esters of polyhydric alcohols, more preferably (meth) acrylic esters of polyhydric alcohols that are liquid at room temperature can be mentioned.

For example, di (meth) acrylates of dihydric alcohols such as ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate and neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Examples thereof include poly (meth) acrylates of a trihydric or higher aliphatic polyhydric alcohol such as trimethylolethane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and pentaerythritol hexaacrylate.

When the epoxy acrylate resin of the formula I exceeds 60% by weight of the polyvalent acrylate composition, the viscosity becomes extremely high, the workability of coating is poor, and when it is less than 1% by weight, a film having excellent surface properties is obtained. I can't.

For this reason, the epoxy acrylate resin of the formula I is used in an amount of 1 to 60% by weight, preferably 1 to 50% by weight, based on the whole polyhydric acrylate compound.

If necessary, a sensitizer, an antioxidant, a leveling agent, a defoaming agent and the like can be added to the ultraviolet-curable polyvalent acrylate composition of the present invention in addition to the above-mentioned essential components.

In particular, the addition of a sensitizer is performed by irradiating ultraviolet rays.
Curing in a short time is effective for preventing coloring of the cured film.

The addition amount of the sensitizer is preferably 1 to 10% by weight based on the polyvalent acrylate composition.

If the amount is less than 1% by weight, the effect of the sensitizer hardly occurs. On the other hand, the addition of 10% by weight is undesirable because the sensitizer itself causes yellowing.

The sensitizers mentioned here include benzoin methyl ether, benzoin ethyl ether, diethoxyacetophenone, benzyl dimethyl ketal,
Hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, benzophenone,
Michler's ketone, 2-chlorothioxanthone, 2,4
-Diethylthioxanthone, and mixtures thereof.

The polyhydric acrylate composition of the present invention can be applied as it is to the surface of an aromatic polycarbonate molded article as a substrate if it has an appropriate viscosity, depending on the means of application. It is.

In order to adjust the viscosity, a monofunctional acrylate such as tetrahydrofurfuryl (meth) acrylate or a diluent such as N-vinylpyrrolidone may be used.

Further, the above-mentioned polyhydric acrylate composition comprises:
From the viewpoint of workability, it is desirable to dissolve it in a solvent and use it so that the concentration is in the range of 10 to 97% by weight.

When a solvent is used, about 3% by weight of the solvent is necessary in order to form a uniform solution. If the concentration of the polyvalent acrylate composition is less than 10% by weight, uniform coating becomes difficult. Become.

For this purpose, as the solvent to be used, methyl ethyl ketone, ethyl acetate, ethyl cellosolve acetate, etc., which are good solvents for polycarbonate, are suitable.

The aromatic polycarbonate molded article to which the method of the present invention is applied is a polycarbonate obtained by polymerizing an aromatic dihydric phenol, typically bisphenol A, and a polycarbonate precursor such as phosgene by a known method. A molded product obtained by converting a resin into a sheet or other shape.

As described above, according to the present invention, a protective film obtained from a functional acrylate compound which is cured by ultraviolet rays is formed on the surface of an aromatic polycarbonate molded product to obtain a polycarbonate molded product having desired surface characteristics. An important object of the present invention is to provide a polycarbonate molded article having excellent durability to long-time use, that is, excellent weather resistance, surface hardness and adhesion.

Of these, in order to satisfy the object of weather resistance, a considerable amount of an ultraviolet absorber is conventionally mixed and used in a polycarbonate coating agent, which causes deterioration in physical properties of a cured film. There were many.

However, the epoxy acrylate resin of the formula I of the present invention itself plays a role of an ultraviolet absorber, and it is not necessary to add a special ultraviolet absorber, so that the physical properties of the cured film can be improved.

The present invention is specifically implemented by the following method. That is, the acrylic composition of the present invention is applied to the surface of an aromatic polycarbonate molded article serving as a base material (a sensitizer is added as necessary to increase sensitivity to light), and a temperature of 70 to 120 ° C is applied. Dry for minutes.

The composition is applied by a known means such as brushing, dipping, spraying and roll coating. Next, it is cured by irradiation with ultraviolet rays.

The surface of the composite polycarbonate molded article thus obtained is excellent in abrasion resistance and chemical resistance, high in surface hardness, good in adhesion to the polycarbonate base of the protective film, and excellent in surface. It has excellent weather resistance such that it does not yellow even after long-time outdoor use, does not crack, and does not reduce the adhesion between the protective film and the polycarbonate substrate. .

In particular, by using the polyvalent acrylate composition of the present invention, a coating having excellent adhesion and surface hardness can be easily formed, and therefore, it is widely used in fields where the characteristics of plastic such as light weight and transparency are to be effectively utilized. For example, the present invention can be used for surface coating of a decorative board using a polycarbonate board, and can provide a surface-coated composite polycarbonate molded article.

Hereinafter, the method of the present invention will be specifically described with reference to Examples and Comparative Examples. In Examples and Comparative Examples, all formulations are by weight unless otherwise specified.

[0051]

【Example】

Synthesis Example Epoxy resin (Epoxy equivalent 231 / equiv, n =
0, R = H) 231 g and ethyl cellosolve acetate 1
00 g was completely dissolved by heating to 120 ° C. in a 500 ml four-necked flask, and then 450 mg of triethylbenzylammonium chloride, 100 mg of 2,6-di-tert-butylphenol, and 72.0 g of acrylic acid were added.
Stir for 8 hours.

The acid value was measured and 2.0 mgKOH / g
Heating and stirring are continued until the temperature becomes less than. After the acid value reached the target, the mixture was allowed to cool at room temperature to obtain an epoxy acrylate resin (n = 0 to 2) represented by Formula I (Sample 1). Further, this was dried under reduced pressure at 30 ° C. for 24 hours to obtain a target product.

[0053]

Examples 1 to 4 The epoxy acrylate resin synthesized above and dipentaerythritol hexaacrylate (DPHA) as a polyvalent acrylate compound were dissolved in a solvent, methyl ethyl ketone, and diluted and adjusted to a solution having a concentration of 50% by weight. did.

In order to further improve the smoothness, a silicon leveling agent (trade name: Florard, manufactured by Sumitomo 3M)
Was added in an amount of 0.1% by weight to the polyvalent acrylate composition.

The polyacrylate resin composition was applied to the surface of a polycarbonate resin sheet using a bar coater and adjusted to 5 μm. After application, the coating was dried at 100 ° C. for 5 minutes.

Next, 300 mm with a high pressure mercury lamp (400 w).
mj light was applied to cure the coating.

The surface properties of the obtained composite polycarbonate resin molded product were measured according to the following test methods. The results are shown in Table 1.

(1) Scratch resistance The coating film surface is reciprocated 30 times while lightly pressing the coated film surface with #OOOO steel wool. Thereafter, the degree of scratches on the coating film surface was determined according to the following criteria, and the abrasion resistance was evaluated. A: no damage B: scratches, but gloss is maintained C: countless scratches, loss of gloss

(2) Adhesion The adhesion was evaluated in accordance with JIS-Z-1552 by a stripping test.

(3) Pencil hardness test Pencil hardness was measured according to JIS-K-5400.

(4) Weathering test Sunshine carbon arc type accelerated weathering tester (manufactured by Suga Test Instruments, Sunshine Weather Meter WE-SUN-
(HC type), the sample was irradiated for 1000 hours, and yellowing of the coating film was evaluated.

[0062]

Example 5 The above synthesized epoxy acrylate resin and trimethylolpropane triacrylate (TMTA) as a polyvalent acrylate compound were dissolved in a solvent, methyl ethyl ketone, and diluted and adjusted to a solution having a concentration of 50% by weight.

In order to further improve the smoothness, a silicon leveling agent (trade name: Florard, manufactured by Sumitomo 3M)
Was added in an amount of 0.1% by weight to the polyvalent acrylate composition.

The polyacrylate resin composition was applied to the surface of a polycarbonate resin sheet using a bar coater, and adjusted to 5 μm. After application, the coating was dried at 100 ° C. for 5 minutes.

Next, the pressure was increased to 300 with a high-pressure mercury lamp (400 w).
mj light was applied to cure the coating.

The surface characteristics of the obtained composited polycarbonate resin molded product were measured in accordance with the above-mentioned test method.
The results are shown in Table 1.

[0067]

Example 6 The above synthesized epoxy acrylate resin and pentaerythritol tetraacrylate (PETA) as a polyvalent acrylate compound were dissolved in a solvent, methyl ethyl ketone, and diluted and adjusted to a solution having a concentration of 50% by weight.

In order to further improve the smoothness, a silicon leveling agent (trade name: Florard, manufactured by Sumitomo 3M)
Was added in an amount of 0.1% by weight to the polyvalent acrylate composition.

This polyacrylate resin composition was applied to the surface of a polycarbonate resin sheet using a bar coater and adjusted to 5 μm. After application, the coating was dried at 100 ° C. for 5 minutes.

Next, 300 mercury was applied with a high-pressure mercury lamp (400 w).
mj light was applied to cure the coating.

The surface properties of the obtained composited polycarbonate resin molded product were measured according to the test method described above.
The results are shown in Table 1.

[0072]

Examples 7 to 10 The above synthesized epoxy acrylate resin and pentaerythritol hexaacrylate (DPHA) as a polyvalent acrylate compound were dissolved in a solvent, methyl ethyl ketone, and diluted and adjusted to a solution having a concentration of 50% by weight. did.

Then, as a sensitizer, 1-hydroxycyclohexylphenyl ketone was added to the acrylic compound in an amount of 5%.
% By weight.

In order to further improve smoothness, a silicon leveling agent (trade name: Florard, manufactured by Sumitomo 3M)
Was added in an amount of 0.1% by weight to the polyvalent acrylate composition.

The polyacrylate resin composition was applied to the surface of a polycarbonate resin sheet using a bar coater and adjusted to 5 μm. After application, the coating was dried at 100 ° C. for 5 minutes.

Next, 100 high pressure mercury lamp (400 w)
mj light was applied to cure the coating.

The surface properties of the obtained composited polycarbonate resin molded product were measured according to the test method described above.
The results are shown in Table 1.

[0078]

Examples 11 to 13 The above synthesized epoxy acrylate resin, pentaerythritol hexaacrylate (DPHA) and ethylene glycol dimethacrylate (EGDM) as polyhydric acrylate compounds were dissolved in methyl ethyl ketone as a solvent, and the concentration was 50%. It was diluted and adjusted to a solution which was wt%.

As a sensitizer, 1-hydroxycyclohexyl phenyl ketone was added to the acrylic
% By weight.

This polyacrylate resin composition was applied to the surface of a polycarbonate resin sheet using a bar coater, and adjusted to 5 μm. After the application, it was dried at 100 ° C. for 5 minutes.

Next, 100 high pressure mercury lamp (400 w)
mj light was applied to cure the coating.

The surface properties of the obtained composited polycarbonate resin molded product were measured according to the test method described above.
The results are shown in Table 1.

[0083]

[Table 1]

[0084]

[Table 2]

[0085]

[Table 3]

[0086]

[Table 4]

[0087]

[Table 5]

[0088]

The composite polycarbonate molded article obtained by forming a protective film obtained by curing the acrylic composition of the present invention with ultraviolet rays has a high hardness, excellent scratch resistance, and excellent weather resistance. Also, the adhesion of the protective film to the polycarbonate substrate is excellent.

Since this is a molded article having excellent surface characteristics while maintaining the inherent properties of plastic such as light weight, toughness, and transparency, it can be suitably used for automobile head lamps, helmet shields, rear panels, and the like.

Continuation of the front page (72) Inventor Takeo Teramoto 1618 Ida, Nakahara-ku, Kawasaki City Nippon Steel Corporation Advanced Technology Research Laboratories (56) References JP-A-62-34926 (JP, A) JP-A-55-139262 (JP, A) JP-A-2-117913 (JP, A) JP-A-61-283617 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 7/00-7 / 18 C08F 299/02 C08G 59/17 C08L 69/00 CA (STN)

Claims (4)

(57) [Claims] 1. A composite polycarbonate molded article having excellent surface characteristics, characterized in that an ultraviolet cured film of the following polyvalent acrylate composition is provided on the surface of an aromatic polycarbonate molded article. Epoxy acrylate resin having the structure of Formula I (Where R represents H or a lower alkyl group, and R ′ is H
Or CH ₃ . n is an integer of 0 to 20. A) a polyvalent acrylate composition containing 1 to 60% by weight of the entire polyvalent acrylate compound. 2. A polyvalent acrylate composition comprising 1 to 1
2. The composite polycarbonate molded article according to claim 1, which contains 0% by weight of a sensitizer. 3. An epoxy acrylate resin having the structure of the formula I on the surface of an aromatic polycarbonate molded product. (Where R represents H or a lower alkyl group, and R ′ is H
Or CH ₃ . n is an integer of 0 to 20. ) Is coated with a polyvalent acrylate composition containing 1 to 60% by weight of the entire polyvalent acrylate compound, and then irradiated with ultraviolet rays to cure the polyvalent acrylate composition to form a protective film. A method for producing composite polycarbonate molded products with excellent surface properties. 4. A polyhydric acrylate composition comprising 1 to 1
The method for producing a composite polycarbonate molded article having excellent surface characteristics according to claim 3, which contains 0% by weight of a sensitizer.