JPH05186620A - Coated molded product and its production - Google Patents

Abstract

PURPOSE:To simply obtain a coated molded product excellent in the fogging resistance and durability at a low cost by forming a coating layer comprising a specific polymer on the surface of a specific molded product. CONSTITUTION:A molded product having a polymer containing structural units originated from a polyfunctional monomer having two or more (meth) acryloyloxy groups in the molecule as main constituting units in at least the surface layer is irradiated with UV rays having a wavelength of <=300nm and subsequently treated with an alkali to form acidic groups in an amount of 0.02-0.2mumol/cm<2> in the surface layer. A coating composition comprising (A) 10-100 pts.wt. of a compound having a functional group having one or more polymerizable double bonds in the molecule, (B) 0-90 pts.wt. of a compound selected from a monomer having one or more polymerizable double bonds in the molecule, its oligomer and its polymer, and (C) 0.1-5.0 pts.wt. of a polymerization initiator is coated on the acidic group-formed molded product, polymerized and subsequently cured to obtain the objective molded product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated molded article excellent in antifogging property and a method for producing the same.

[0002]

2. Description of the Related Art Plastic molded products have advantages such as light weight, excellent impact resistance, low cost, and easy molding process, and are utilized in various fields by making use of these advantages. .. However, fog that occurs in showcases, mirrors, goggles, glasses, side mirrors of bicycles, etc. blocks the field of view. For this reason, conventionally, a method of applying an antifogging agent to a molded product has been generally performed in order to prevent these problems.

[0003]

The above-mentioned conventional method is
Since the anti-fog agent is extremely soluble in water, when the surface of the applied molded article is exposed to water vapor or high humidity, there is a disadvantage that it flows off together with coagulated water. In addition, there are inconveniences that the antifogging property is deteriorated and that the performance is not maintained for a long period of time. An object of the present invention is to provide a coated molded article excellent in antifogging property even under the above conditions and a method for producing the same.

[0004]

SUMMARY OF THE INVENTION The present inventors have completed the present invention as a result of intensive studies in view of the above-mentioned current situation in order to maintain the antifogging effect for a long period of time. That is, the coated molded article according to the present invention has 2 molecules per molecule.
Having as a main constituent unit a structural unit derived from a polyfunctional monomer having at least one (meth) acryloyloxy group, and having 0.02 μmol / cm ² to 0.2 on its surface.
At least one functional group having a polymerizable double bond in one molecule is formed on the surface of a molded article having a surface layer portion made of a polymer having a μmol / cm ² acidic group, and at least 1
Compounds (A) having 100 to 100 phosphoric acid type OH groups (A)
Obtained by polymerizing parts by weight and 0 to 90 parts by weight of at least one component (B) selected from monomers, oligomers and polymers having at least one polymerizable double bond in one molecule. It is excellent in antifogging property because a coating layer made of the polymer is formed.

In a preferred embodiment of the coated molding of the present invention, the functional group having at least one polymerizable double bond in one molecule can be acrylate or methacrylate.

Furthermore, in a preferred embodiment of the coated molded article according to the present invention, the compound (A) is replaced by the following general formula (I).

[Chemical 2] (In the formula, R1 represents a hydrogen atom or a methyl group, R2 represents an alkylene group having 2 to 8 carbon atoms, n is 1 to 5, and m is 0.
~ 5, X represents an integer of 1-2. ) At least one selected from the group consisting of monomers, oligomers and polymers
It can be a component of a seed.

The method for producing a coated molded article according to the present invention comprises:
A wavelength of 300 nm or less is applied to a molded product having at least its surface layer a polymer having a structural unit derived from a polyfunctional monomer having two or more (meth) acryloyloxy groups in one molecule as a main constituent unit. The surface layer is exposed to ultraviolet rays containing 0.02 μmo
1 / cm ^{2 to} 0.2 μmol / cm ² of acidic group is formed,
Next, (A) at least one functional group having a polymerizable double bond in one molecule and at least one phosphoric acid type O
10 to 100 parts by weight of a compound having an H group and (B) 0 to 90 parts by weight of at least one component selected from a monomer, an oligomer and a polymer having at least one polymerizable double bond in one molecule. And a coating composition comprising 0.1 to 5.0 parts by weight of the (C) polymerization initiator are applied on the surface of the molded article, and the composition is polymerized and cured.

The coated molding of the present invention and the method for producing the same will be described below in detail. In the present invention, first, at least the surface layer portion of the molded product is formed by polymerizing a composition containing a polyfunctional monomer having two or more (meth) acryloyloxy groups in one molecule as a main component. Examples of this polyfunctional monomer include 1,4-
Butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (Meth) acrylate, dipropylene glycol di (meth) acrylate, 3-methylpentanediol di (meth) acrylate, diethylene glycol bis β- (meth) acryloyloxypropionate, trimethylolethane di (meth) acrylate, trimethylolpropane Tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tri (2-hydroxyethyl) isocyanate di (Meth) acrylate, pentaerythritol tetra (meth) acrylate, 2,3-bis (meth) acryloyloxyethyloxymethyl [2.2.1] heptane, poly 1,2-butadiene di (meth) acrylate, 1,2- Bis (meth) acryloyloxymethylhexane, nonaethylene glycol di (meth) acrylate, tetradecane ethylene glycol di (meth) acrylate, 10-decanediol di (meth) acrylate, 3,8-bis (meth) acryloyloxymethyl tricyclo [5.2.10] Decane,
Hydrogenated bisphenol A di (meth) acrylate,
2,2-bis (4- (meth) acryloyloxydiethoxyphenyl) propane, 1,4-bis ((meth) acryloyloxymethyl) cyclohexane, hydroxypivalate neopentyl glycol di (meth) acrylate, bisphenol A di Glycidyl ether di (meth) acrylate, epoxy modified bisphenol A
Examples thereof include di (meth) acrylate. As the polyfunctional monomer, only one kind may be used, or two or more kinds may be used in combination. If necessary, they can be used in combination with a monofunctional monomer for copolymerization. Further, it is appropriate that the polyfunctional monomer is 30% by weight or more in the composition.

A crosslinked structure is formed by the (meth) acryloyloxy group in the surface layer portion formed by polymerizing the composition containing the above-mentioned polyfunctional monomer as a main component. When the surface layer portion is formed only by using a monofunctional monomer such as methyl methacrylate without using the above-mentioned polyfunctional monomer, even if UV irradiation and alkali treatment are performed later, only a small amount of acidic group is present. I can't get it. That is, in the present invention, the use of a polyfunctional monomer [a monomer having two or more (meth) acryloyloxy groups in one molecule] as a main component is one of the important constituent elements.

In the present invention, the surface layer part may be formed by coating the surface of a molded article made of a suitable base material with the above-mentioned polyfunctional monomer and supplying it, and polymerizing it. Alternatively, the entire molded article may be formed only by the composition containing the polyfunctional monomer as the main component as described above.

The base material is preferably an organic material (particularly an organic polymer material). However, a composite material of an inorganic material and an organic material or the like can also be used as the base material. Examples of the organic polymer material include various resins such as acrylic resin, polycarbonate resin, polyester resin, polystyrene resin, and vinyl chloride resin. Further, in the method of coating the surface of the substrate with the polyfunctional monomer as described above, the thickness of the polymer in the surface layer portion is preferably 1 μm or more, and more preferably 3 μm or more. However, as described above, the base material is not always necessary, and the entire molded product may be composed of a polymer of the above-mentioned polyfunctional monomer.

Next, the surface layer portion formed by polymerization of the polyfunctional monomer is irradiated with ultraviolet rays having a wavelength of 300 nm or less. This ultraviolet irradiation may be carried out by appropriately selecting a wavelength range and irradiation time capable of providing energy to such an extent that a part of the ester bond of the polymer can be cleaved. Since different molecules of the polymer have different binding energies between molecules, it cannot be generally specified, but it is desirable that the ultraviolet region gives an energy of about 4 eV or more. This ultraviolet ray is 180 nm to 30
It is desirable to include a wavelength of 0 nm. It should be noted that the acid groups are not sufficiently generated only by irradiating with ultraviolet rays.

Next, the UV-irradiated portion is subjected to usual alkali treatment, that is, immersion in an alkaline aqueous solution. By this alkali treatment, an acid group is generated in the surface layer part in combination with the above-mentioned action of ultraviolet irradiation. Examples of the alkaline aqueous solution used for the alkaline treatment include an aqueous solution of sodium hydroxide, potassium hydroxide and the like, and an alkaline aqueous solution in which various solvents such as alcohol are further added. The condition of the alkali treatment cannot be unconditionally specified because it varies depending on the amount of UV irradiation, the composition of the UV irradiation site, the form of the molded product, the desired performance, etc. It is desirable to use an aqueous solution with a concentration of
30% by weight is preferred. In addition, the temperature of alkali treatment is
The temperature is 0 to 100 ° C, preferably 20 to 80 ° C. The alkali treatment time is 0.01 to 100 hours, preferably 0.1 to 10 hours.

As a result of the above-mentioned ultraviolet irradiation and alkali treatment, usually 0.02 μmol / cm is observed on the surface portion of the molded product.
A surface layer portion containing two or more acidic groups is formed. That is,
A high concentration of acidic groups is concentrated on the surface layer of the molded article. The content of this acidic group is 0.02-0.2μ.
mol / cm ² is more preferable, 0.03-0.15μ
Mol / cm ² is particularly preferred.

The value of the content of the acidic group in the present invention is represented by the number of moles (μmol / cm ² ) of the basic dye that can be adsorbed per unit area of the surface of the molded product. This value is a value obtained by the following method. (1) 0.1 N sodium acetate buffer (pH 4.
Create 5). (2) A solution having a methyl violet concentration of 1.0 g / l is prepared based on the buffer solution of (1). (3) Add a 50 × 50 (mm ² ) molded product to the solution.
Immerse for 2 hours (temperature 25 ° C.). (4) The molded product is taken out and washed with water. (5) Wipe off the water content of the molded product after washing with water. (6) The molded product was placed in an N-dimethylformamide solution for 2 minutes.
The dye is extracted and dissolved by soaking for 4 hours. (7) The absorbance of the dye extract is measured using 589 nm light. (8) Separately, a calibration curve of the dye concentration is obtained from the dye solution dissolved in the N-dimethylformamide solution, and the basic dye concentration per unit area of the molded product is calculated.

That is, the content of acidic groups (0.02 μmol / cm ² or more) in the present invention means the binding ability of the surface. In the present invention, the acidic groups are contained appropriately only in the surface portion of the polymer of the surface layer portion, the acidic groups are not contained so much in the inner side thereof, and the acidic groups are concentrated on the surface portion. Therefore, in the surface portion of the surface layer portion, the acidic group reacts with the coating layer having antifogging property in the subsequent treatment, and the properties of both react to form a molded product having very good properties. The thickness of the layer containing the acidic group is preferably within 1 μm from the outermost surface to the inside,
It is more preferably within 0.8 μm. If the thickness of the layer containing an acidic group exceeds 1 μm, the required surface hardness may not be obtained. The lower limit of the thickness of the layer cannot be unconditionally specified because it is influenced by the relationship of the acidic group content and the like, but it is generally about 0.01 μm.

In place of this treatment of the present invention in which ultraviolet irradiation and alkali treatment are successively performed, two or more molecules per molecule can be prepared by a conventional method of introducing an acidic group (plasma treatment, light irradiation graft polymerization, chromic acid treatment, etc.). Even when it is applied to a polymer of a polyfunctional monomer having a (meth) acryloyloxy group, it is difficult to obtain good results in various aspects such as the amount of acidic groups, hardness, and process easiness. Appropriate washing with water is usually performed on the molded product after the alkali treatment. Moreover, you may neutralize and wash with an inorganic acid or an organic acid as needed.

Next, on the surface of this molded product, a compound (A) having at least one functional group having a polymerizable double bond in one molecule and at least one phosphoric acid type OH group (eg, EO). A compound such as modified phosphoric acid diacrylate, EO modified phosphoric acid acrylate, EO modified phosphoric acid methacrylate, or EO modified phosphoric acid dimethacrylate is applied. Since these compounds have both 1 and 2 (meth) acryloyl groups and a phosphoric acid group, for example, a photopolymerization initiator or a thermal polymerization initiator is added to cause a polymerization reaction to occur and to form a coating layer. By forming it, excellent antifogging property can be imparted. However, since the formed coating layer has insufficient hardness, it is desirable in the present invention to use the compound (A) in combination with the following component (B).

Component (B) that can be used in the present invention
Is, for example, dipentaerythritol hexaacrylate,
Pentaerythritol triacrylate, trimethylolpropane triacrylate, urethane acrylate,
Monomers, oligomers and polymers such as epoxy acrylate, tetrahydrofuran acrylate, hydroxypropyl acrylate and 2-hydroxyethyl acrylate. The mixing ratio of the compound (A) to the component (B) is 10 to 100 parts by weight of the compound (A) and 0 to the component (B).
To 90 parts by weight, preferably compound (A) 1
The range is 5 to 95 parts by weight and the component (B) is 5 to 85 parts by weight.

The catalyst which can be used in the present invention is, for example, benzophenone, acetophenone, benzyl or benzoin. The thermal polymerization initiator is, for example, benzoyl peroxide, azobisisobutyronyl or the like. The amount of these polymerization initiators used is not particularly limited, but the polymerization initiator (C) is added to 100 parts by weight of the total amount of the compound (A) and the component (B).
It can be in the range of 0.1 to 5.0 parts by weight.

The above-mentioned coating composition may use various organic solvents as a diluent in order to facilitate the coating on the surface of the molded article of the present invention. A known method may be used to apply the coating composition of the present invention to the surface of a molded article. For example, a method such as brush coating, flow coating, spray coating, spin coating or dip coating may be used. The dip coating method is preferable from the aspects of coating workability of the composition, smoothness of coating, uniformity, adhesion of the coating to a molded article,
The spray coating method is preferable depending on the shape of the molded product.

The coating amount of the coating composition is 1
It is good to apply in the range of -30 μm, preferably 1-10 μm. When the film thickness is less than 1 μm, sufficient antifogging property and scratch resistance cannot be obtained, and when the film thickness exceeds 30 μm, the adhesion to the molded product is deteriorated and the coating film is apt to be cracked. As a method of polymerizing and curing the coating film applied on the surface layer of the molded article, a method by thermal polymerization or a known method of irradiating various active energy rays such as ultraviolet rays, X-rays and γ rays can be applied. In the case of thermal polymerization, for example, polymerization conditions of 100 to 130 ° C. and 10 minutes to 5 hours can be adopted. Further, the coating composition of the present invention, in the range not impairing the effects of the present invention, a colorant, an ultraviolet absorber,
Various additives such as a heat stabilizer can be blended and used.

[0023]

EXAMPLES The present invention will be described in more detail below with reference to examples. Example 1 10% by weight of dipentaerythritol hexaacrylate, 20% by weight of equimolar condensate of succinic acid / trimethylolethane / acrylic acid, 5% by weight of tetrahydrofurfuryl acrylate, photopolymerization initiator "Darocur 1173"
A solution consisting of 34% by weight of 1.2% -containing isopropanol (manufactured by Merck & Co., Inc.) and 20% by weight of toluene was prepared. A 2 mm-thick polymethylmethacrylate resin plate was immersed in this solution, and then slowly pulled up at a speed of 0.2 cm / sec to form a film on the surface of the resin plate.

Next, this was kept at 35 ° C., and the central wavelength was set to 365 nm at a distance of 15 cm from both sides of the resin plate.
Irradiation was performed with a high-pressure mercury lamp having a pressure of 840 mJ / cm ² . As a result, a cured coating having a thickness of 3.5 μm was obtained on the surface of the resin plate. Irradiation was performed from above the resin plate on which the cured coating was formed, using a low pressure mercury lamp having a central wavelength of 254 nm at an irradiation dose of 1300 mJ / cm ² . The acidic group in the surface layer of the resin plate after irradiation was measured with a basic dye, methyl violet, and was found to be 0.0
It was 12 μmol / cm ² . This resin plate was immersed in a 20% by weight aqueous solution of sodium hydroxide at room temperature for 3 hours, washed with water and dried, then immersed in a 0.05% by weight aqueous solution of sulfuric acid for 1 minute at room temperature, washed with water and dried. The amount of acidic groups on the resin plate after the alkali treatment was increased to 0.05 μmol / cm ² .

Next, 65 parts by weight of compound (A) EO-modified phosphoric acid acrylate (manufactured by Kyoeisha: Light Ester PA)

[Chemical 3] Component (B) 2-hydroxyethyl acrylate 20 parts by weight Trimethylolpropane triacrylate 15 parts by weight Catalyst (C) 0.1N hydrochloric acid 0.5 parts by weight Azobisisobutyronitrile 1.5 parts by weight The above solutions are mixed. The coating composition was prepared. Using this solution, a resin plate having an acidic group on its surface was dip-coated and reacted at 100 ° C. for 2 hours to obtain a coated molded article having a cured coating film of 3 μm.

Example 2 The following solution was prepared as a coating composition.

75 parts by weight of Compound (A) EO-modified phosphoric acid dimethacrylate (Nippon Kayaku: Kamaya-PM-2)

[Chemical 4] Component (B) 2-hydroxyethyl acrylate 20 parts by weight trimethylolpropane triacrylate 15 parts by weight Catalyst (C) 0.1 N hydrochloric acid 0.5 parts by weight Azobisisobutyronitrile 1.5 parts by weight Using this solution, A resin plate having an acidic group is dip-coated on the surface of Example 1 and reacted at 100 ° C. for 2 hours,
A coated molding having a cured coating film of 3 μm was obtained.

Comparative Examples 1 to 3 Instead of the resin plate having an acidic group on the surface used in Examples, 10% by weight of dipentaerythritol hexaacrylate and an equimolar condensate of succinic acid / trimethylolethane / acrylic acid 20 %, Tetrahydrofurfuryl acrylate 5% by weight, photoinitiator "Darocur 117
3 "(manufactured by Merck & Co.) 1.2% Isopropanol 34
A solution consisting of 20% by weight of toluene and 20% by weight of toluene was prepared. A 2 mm-thick polymethylmethacrylate resin plate was immersed in this solution, and then slowly pulled up at a speed of 0.2 cm / sec to form a film on the surface of the resin plate.

Next, this was irradiated at a dose of 840 mJ / cm ² using a high pressure mercury lamp having a central wavelength of 365 nm set at a distance of 15 cm from both sides of the resin plate while keeping it at 35 ° C. As a result, the thickness of the resin plate 3.
A cured coating of 5 μm was obtained. This sample is referred to as Comparative Example 1.
In Comparative Example 2, a surface-hardened acrylic resin plate (trade name: Acrylite MR, manufactured by Mitsubishi Rayon Co., Ltd.) was used, and in Comparative Example 3, an ordinary acrylic resin plate (trade name: Acrylite L, manufactured by Mitsubishi Rayon Co., Ltd.). Was used. Incidentally, each of the surface acid groups amount, Comparative Example 1 is 0.001μmol / cm ^2, Comparative Example 2 is 0.017μmol / cm ^2, the Comparative Example 3 0.00
It was 7 μmol / cm ² .

Table 1 below shows the results of performance evaluation. The evaluation was based on the following method. (Evaluation method) 1. Antifogging vapor test: The coated molded article was left for 30 seconds at 50 mm on a warm water bath kept at 50 ° C., and the generation of fogging was observed. 2. Anti-fogging durability After the coated molded article was left under high humidity at 50 ° C. and 98% RH for 200 hours, the occurrence of fogging was observed by the same evaluation method as above.

[0031]

[Table 1] Evaluation criteria: ◯: No fog is generated at all, and excellent antifogging property is obtained. X: Fogging is generated and no antifogging effect is observed. As is clear from the above results, the coated molded article of the present invention has an antifogging property. It has excellent durability.

[0032]

INDUSTRIAL APPLICABILITY The coated molded article of the present invention requires that the coating layer has a specific chemical structural component excellent in antifogging property, maintains an excellent antifogging effect, and the surface and the coating layer are chemically resistant. It has excellent durability as it is connected to. Further, the method for producing a molded article of the present invention can be carried out with simple steps and inexpensive equipment.

Continuation of front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C08J 7/04 B 7258-4F C09D 143/02 PGL 7921-4J

Claims (4)

[Claims] 1. A structural unit derived from a polyfunctional monomer having two or more (meth) acryloyloxy groups in one molecule as a main constitutional unit and having 0.02 on its surface.
the surface of the molded product having a surface layer portion made of a polymer having an acidic group ^{μmol / cm 2 ~0.2μmol / cm 2} , and a functional group having at least one polymerizable double bond in one molecule, 10 to 100 parts by weight of the compound (A) having at least one phosphoric acid OH group, and at least one selected from a monomer, an oligomer and a polymer having at least one polymerizable double bond in one molecule. A coated molded article having excellent antifogging properties, which is formed by forming a coating layer made of a polymer obtained by polymerizing 0 to 90 parts by weight of the component (B). 2. The coated molded article according to claim 1, wherein the functional group having at least one polymerizable double bond in one molecule is acrylate or methacrylate. 3. A compound (A) is represented by the following general formula (I): (In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 2 to 8 carbon atoms, n is 1 to 5, and m is 0.
~ 5, X represents an integer of 1-2. ) At least one selected from the monomers, oligomers and polymers represented by
The coated molded article according to claim 1, which is a compound of a kind. 4. A molded product having a polymer having as a main constituent unit a structural unit derived from a polyfunctional monomer having two or more (meth) acryloyloxy groups in one molecule in at least its surface layer portion, Irradiation with ultraviolet rays having a wavelength of 300 nm or less, alkali treatment is performed to form 0.02 μmol / cm ^{2 to} 0.2 μmol / cm ² acidic groups on the surface layer portion, and then (A) at least 1 in one molecule. 10 to 100 parts by weight of a compound having at least one polymerizable double bond and a compound having at least one phosphoric acid OH group, and (B) at least one polymerizable double bond in one molecule. A coating composition comprising 0 to 90 parts by weight of at least one component selected from the monomers, oligomers, and polymers and 0.1 to 5.0 parts by weight of the (C) polymerization initiator, A method for producing a coated molded article excellent in antifogging property, which is obtained by applying the composition onto a surface, polymerization and curing.