JP5614008B2 - Manufacturing method of plastic material injection molded body - Google Patents

Description

  The present invention relates to a method for producing a plastic material injection molded body. Specifically, by removing organic waste adhering to the surface of the plastic material injection molded body and modifying the surface of the plastic material injection molded body, the modified surface of the molded body and paint / hard coat / adhesive / coating The present invention relates to a surface modification method for improving adhesion with an agent, plating, vapor deposition, sputtering, or the like.

  In many plastic products, paint, hard coat, adhesive, coating agent, plating, vapor deposition, sputtering, etc. are applied or coated on the plastic surface in order to improve the appearance and function of the product, but the adhesion is sufficient. There was a problem that it peeled off easily or the appearance was damaged.

  In order to solve these problems, for example, a method for improving printability by irradiating a printing surface of a polycarbonate sheet with ultraviolet rays having a wavelength of 200 to 400 nm is disclosed (see Patent Document 1). There is no specific description of the ultraviolet energy to be irradiated in this document.

Also, a plastic surface modification method that defines the light quantity of an ultraviolet lamp is disclosed (see Patent Document 2). The range of the amount of light in this document is 1 to 3000 mJ / cm ² , but sufficient adhesion with the coating material was not obtained within this range.
Furthermore, the manufacturing method of the polycarbonate resin film irradiated with the intensity | strength of 100-900 mJ of ultraviolet irradiation energy per 1 cm < ² > of polycarbonate resin film is disclosed (refer patent document 3). However, even with the same ultraviolet irradiation energy, there is a problem that if the irradiation distance is short, the temperature of the plastic surface becomes high, causing discoloration, deterioration of physical properties, and deformation.

JP 63-12463 A JP 2002-88178 A JP 2000-327808 A

The present invention, the surface of the plastics material injection-molded body modified, and an object thereof is to provide a resultant formed form by a method of improving the adhesion between the formed feature surface-modified layer and the Ha Doko bets.

As a result of intensive studies to achieve the above object, the present inventors removed organic dust adhering to the surface of the plastic material without damaging the original performance of the plastic material by irradiating specific ultraviolet energy. and, a plastic material surface was modified, and completed the present invention have found that to improve the adhesion between the modified surface and Ha Doko bets.
That is, the gist of the present invention, the surface of the plastic material injection molded body, the temperature of the surface of the 400~700kJ / mol ultraviolet energy plastic material injection molded article of, [the glass transition temperature of the plastic material (Tg) -15 ℃] or less, and by irradiation so as to be 105 ℃ or more , a modified layer is formed with a thickness of 1 to 500 nm from the surface of the injection molded body , and then the surface of the hard coat is formed on the surface of the modified layer It is a manufacturing method of the plastic material injection molding characterized by performing a process .

  The method for producing a plastic material injection molded body according to the present invention removes organic waste adhering to the surface of the plastic material injection molded body without impairing the original performance of the plastic material, and modifies the surface of the plastic material. Adhesion with a coat, an adhesive, a coating agent, plating, vapor deposition, sputtering, or the like can be improved.

Hereinafter, the present invention will be described in detail.
[1. Surface treatment object]
Surface treatment objects are plastic materials made of synthetic resin made mainly of high-molecular substances, including additives, inorganic and organic fillers, plasticizers, reinforcing agents such as glass fibers and carbon fibers, etc. Is added. Specifically, thermoplastic resins such as vinyl chloride resin, acrylic resin, styrene resin, polyethylene, polypropylene, polyamide resin, polycarbonate resin, acetal resin, polyester resin, polyphenylene ether resin, phenol resin, urea resin, melamine resin, alkyd resin And thermosetting resins such as unsaturated polyester resins, silicon resins, polyurethane resins, and epoxy resins. Also included are plastic alloy materials in which these two or more types of plastics are mixed. Of the plastic material and the plastic alloy material, an aromatic polycarbonate resin and an alloy mainly composed of an aromatic polycarbonate resin are preferable.

  The aromatic polycarbonate resin used in the present invention is an optionally branched thermoplastic polymer or copolymer obtained by reacting an aromatic dihydroxy compound or a small amount thereof with phosgene or a carbonic acid diester. It is a polymer. The production method of the aromatic polycarbonate resin is not particularly limited, and those produced by a conventionally known phosgene method (interfacial polymerization method) or melting method (transesterification method) can be used. Further, when the melting method is used, a polycarbonate resin in which the amount of OH groups of terminal groups is adjusted can be used.

  As the raw material aromatic dihydroxy compound, 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A), tetramethylbisphenol A, bis (4-hydroxyphenyl) -p-diisopropylbenzene, hydroquinone, resorcinol, 4 , 4-dihydroxydiphenyl and the like, preferably bisphenol A. In addition, a compound in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compound can also be used.

  In order to obtain a branched aromatic polycarbonate resin, a part of the above-mentioned aromatic dihydroxy compound is mixed with the following branching agents, that is, phloroglucin, 4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl). Heptene-2,4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptane, 2,6-dimethyl-2,4,6-tri (4-hydroxyphenylheptene-3,1, Polyhydroxy compounds such as 3,5-tri (4-hydroxyphenyl) benzene and 1,1,1-tri (4-hydroxyphenyl) ethane, and 3,3-bis (4-hydroxyaryl) oxindole (= isa) Tin bisphenol), 5-chloruisatin, 5,7-dichloroisatin, 5-bromoisatin, etc. Dose, the aromatic dihydroxy compound is 0.01 to 10 mol%, preferably 0.1 to 2 mol%.

  As the aromatic polycarbonate resin, among the above-mentioned, polycarbonate resin derived from 2,2-bis (4-hydroxyphenyl) propane, or 2,2-bis (4-hydroxyphenyl) propane and other aromatic dihydroxy Polycarbonate copolymers derived from the compounds are preferred. Further, it may be a copolymer mainly composed of a polycarbonate resin, such as a copolymer with a polymer or oligomer having a siloxane structure. Furthermore, you may mix and use 2 or more types of the aromatic polycarbonate resin mentioned above.

  In order to adjust the molecular weight of the aromatic polycarbonate resin, a monovalent aromatic hydroxy compound may be used. For example, m- and p-methylphenol, m- and p-propylphenol, p-tert-butylphenol, p- Long chain alkyl substituted phenols and the like.

  The molecular weight of the aromatic polycarbonate resin is arbitrary depending on the use, and may be appropriately selected and determined. From the viewpoint of moldability, strength, etc., the molecular weight of the (A) aromatic polycarbonate resin is determined by using methylene chloride as a solvent, temperature The viscosity average molecular weight [Mv] converted from the solution viscosity measured at 25 ° C. is preferably 10,000 to 40,000, more preferably 10,000 to 30,000. As described above, when the viscosity average molecular weight is 10,000 or more, the mechanical strength tends to be further improved, which is more preferable in the case of use in applications requiring high mechanical strength. On the other hand, by setting it as 40,000 or less, there exists a tendency to suppress and improve fluidity | liquidity fall more, and it is more preferable from a viewpoint of easy moldability.

  Among them, the viscosity average molecular weight is preferably 10,000 to 28,000, more preferably 12,000 to 25,000, and particularly preferably 14,000 to 22,000. Two or more types of aromatic polycarbonate resins having different viscosity average molecular weights may be mixed. In this case, an aromatic polycarbonate resin having a viscosity average molecular weight outside the above preferred range may be mixed. In this case, the viscosity average molecular weight of the mixture is preferably within the above range.

  Other polymers, flame retardants, impact modifiers, plasticizers, mold release agents, ultraviolet absorbers, stabilizers, compatibilizers, elastomers, rubber components, colorants (carbon black) , Pigments such as titanium oxide, dyes such as bluing agents), glass fibers, glass beads, glass flakes, carbon fibers, fibrous magnesium, potassium titanate whiskers, ceramic whiskers, mica, talc, clay, calcium silicate, etc. You may contain 1 type, or 2 or more types, such as an agent and a filler.

[2. Release agent]
The mold release agent has the effect of smoothing the mold release at the time of molding and reducing the deformation of the molded product and the residual stress of the molded product, especially necessary for plastic material injection molded products such as headlamp lenses with a three-dimensional curved surface It is essential. On the other hand, when a lot of these release agents are added, the release agents are deposited on the surface of the plastic material injection molded product, and these adhere to paints, hard coat paints, adhesives, coating materials, plating, vapor deposition, sputtering, etc. There is a problem that inhibits sex.

In addition, what is generally called a lubricant is contained in a mold release agent.
Examples of mold release agents include waxes, higher fatty acids, higher fatty acid salts, higher fatty acid esters, silicone oils, fluorinated alkyl compounds, polyvinyl alcohol, low molecular weight polyethylene, polyolefin wax, vegetable protein derivatives, carboxylic acid esters, polysiloxanes. Compound, paraffin wax, polycaprolactone, stearic acid, stearic acid ester, magnesium stearate and the like can be mentioned.

  As content of the mold release agent with respect to a plastic material, 0.001-5 mass% is preferable, and 0.01-1 mass% is further more preferable. If it is less than 0.001% by mass, the effect of releasability cannot be obtained, and if it exceeds 5% by mass, the plastic is decomposed and the original characteristics of the plastic material cannot be obtained.

[3. UV lamp]
The ultraviolet lamp used in the present invention is an ultraviolet lamp having a peak at a shorter wavelength than a high-pressure ultraviolet lamp such as an ultraviolet curing lamp which is generally used in a wide range. In general, energy is higher as the wavelength is shorter, not limited to ultraviolet rays, and in particular, a lamp having a peak around 185 nm has ultraviolet energy of 647 kJ / mol, and can cut the main chain and side chain of the plastic molecule (carbon-carbon double The bond energy of the bond is 607 kJ / mol).

  Further, the wavelength can be further stabilized by controlling the tube wall temperature of the ultraviolet lamp by water cooling or air cooling. The tube wall temperature is preferably 30 to 60 ° C. If it exceeds this range, the ultraviolet energy is lowered, the main chain or side chain of the plastic molecule cannot be cleaved, and sufficient adhesion cannot be obtained.

[4. Cleaning effect of plastic material injection molding surface by UV energy irradiation]
When ultraviolet energy of 400 to 700 kJ / mol is irradiated in the air, oxygen molecules are decomposed simultaneously with the cutting of organic dust molecules adhering to the surface of the plastic material injection molded body. Oxygen molecules are decomposed to generate active single molecules of O, which combine with the remaining oxygen molecules to generate ozone. The generated ozone is further decomposed by irradiation with ultraviolet energy, and active single molecules O are generated. The active single molecule O oxidizes by attaching to the surface of dust that has been activated by cleavage of the molecule. The active single molecule O binds and the oxidized organic substance is changed to a volatile substance such as CO ₂ and H ₂ O and removed.

Further, since the treated organic matter is discharged out of the apparatus at the same time as ozone is discharged, it is difficult for redeposition of dust generated by a method such as wet cleaning to occur. Since the present invention is dry cleaning with light, it is possible to maintain a clean environment without worrying about secondary contamination or contamination with organic compounds.
The release agent deposited on the surface of the plastic material injection molded product is also removed by the UV energy irradiation, so the modified surface and paint, hard coat, adhesive, coating agent, plating, vapor deposition, sputtering, etc. Since the adhesion is not hindered and the adhesion is improved, a good surface-treated plastic material injection-molded article can be obtained.

[5. Effect of surface modification of plastic materials by UV energy irradiation]
When the ultraviolet energy of 400 to 700 kJ / mol is irradiated, the main chain and side chain of the plastic molecule are cleaved. H generated by the cleavage, O of the active single molecule, and C of the main chain are combined to form a hydrophilic group such as OH, CHO, and COOH. These hydrophilic groups are bonded as intermediate groups for paint, hard coat, adhesive, coating material, plating, vapor deposition, and sputtering. Paints, hard coats, adhesives, coating agents, plating, vapor deposition, sputtering, etc. combined with intermediate groups are changed to chemical bonds, enabling strong adhesive strength.

[6. Modified layer on the surface of plastic material injection-molded body]
When the main chain and side chain of the plastic molecule are cut by irradiation with ultraviolet energy, a modified layer is generated on the surface of the plastic material injection molded body according to the degree. About this modified layer, the cross section of a plastic material injection molding can be cut out, and the surface vicinity can be expanded and observed using SEM, TEM, etc. The thickness of the modified layer measured therefrom is preferably 1 to 500 nm, more preferably 1 to 100 nm, and particularly preferably 1 to 20 nm. This modified layer is a holding layer for paints, hard coats, adhesives, coating agents, plating, vapor deposition, sputtering, etc., so it is indispensable for improving the adhesion of these layers. Cannot be obtained. On the other hand, if the modified layer is too thick, the original strength of the plastic cannot be obtained, or the modified layer may be peeled off.

[7. UV energy]
The ultraviolet energy of 400 to 700 kJ / mol exerts a cleaning effect and a surface modification effect on the surface of the plastic material injection molded body, but if it is less than 400 kJ / mol, the molecular chain and the side chain cannot be cut, Sufficient adhesion with the coating cannot be obtained. On the other hand, if it is higher than 700 kJ / mol, the molecular cutting of the plastic material is promoted, the molecular weight of the plastic material is lowered, and the original performance of the plastic material cannot be obtained. A preferable amount of ultraviolet energy is 500 to 680 kJ / mol, and more preferably 607 to 660 kJ / mol (607 kJ / mol is a binding energy of a carbon-carbon double bond).

[8. Surface temperature of molded plastic material]
In the present invention, it is preferable to control the irradiation of ultraviolet energy so that the surface temperature of the plastic material molded body is equal to or lower than [glass transition temperature of plastic material (Tg) −15 ° C.]. When the surface temperature is equal to or higher than [Tg-15] ° C. of the plastic material (that is, when the surface temperature is a value close to Tg), the modified layer on the surface of the plastic material injection molded body becomes thick. There is a risk that it may not be obtained or the modified layer may be peeled off.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
〔raw materials〕
Plastic material: polycarbonate resin, Iupilon (registered trademark) S-3000N (transparent color) manufactured by Mitsubishi Engineering Plastics.
Mold release agent: Beeswax (mixture of wax ester, free fatty acid, free alcohol, hydrocarbon, etc.) manufactured by Ota Kasei.
Ultraviolet absorber: manufactured by Sipro Kasei Co., Ltd., trade name “SEESORB709”
Benzotriazole ultraviolet absorber, 2- (2-hydroxy-5-t-octylphenyl) -2H-benzotriazole.
Phosphorus stabilizer: manufactured by Asahi Denka Kogyo Co., Ltd., trade name “ADK STAB 2112”,
Tris (2,4-di-tert-butylphenyl) phosphite.
[Formation of test plate]
A polycarbonate resin, a release agent, an ultraviolet absorber, and a phosphorus stabilizer are blended in the amounts shown in Tables 1 to 4 so that the total amount becomes 100% by mass (% in the table represents% by mass), and injection molding is performed. A 100 mm × 150 mm test plate was molded, and a 3.2 mm thick portion was evaluated.
Molding machine: J220EV-P (Clamping force: 220 ton) manufactured by Nippon Steel Works
Molding machine cylinder temperature:
(Nozzle side) 300 ° C, 300 ° C, 300 ° C, 290 ° C, 280 ° C (hopper side)
Mold temperature: (fixed side) 80 ℃, (movable side) 80 ℃
The glass transition temperature (Tg) of this material was 145 ° C. by the DSC method.
[Ultraviolet irradiation test]
The following apparatus was used to irradiate the amount of ultraviolet energy described in the comparative example.
Ultraviolet irradiation device: PHOTO SURFACE PROCESSOR PL16-110 manufactured by Sen Engineering Co., Ltd.
[Hard coat treatment]
The surface of one side of the test plate was hard-coated using an ultraviolet curing UVHC3000K manufactured by Momentive.

[Method of evaluating physical properties of molded products]
(1) Thickness of the modified layer:
Cut out the cross section of the plastic material injection-molded body that has been hard-coated, and magnified the cross section near the plastic surface with a transmission electron microscope TEM (JEM-1200EXII, manufactured by JEOL Ltd.) to a magnification of about 100,000 times. The thickness of the modified layer existing between the hard coat layer and the hard coat layer was measured.
(2) Wettability:
A wettability reagent made by Wako Pure Chemical Industries, Ltd. was applied to the surface of the plastic material injection molded body with a cotton swab, and the spread was observed to determine whether the surface was wet or repelled. The wettability was judged from the highest wettability reagent wetted on the surface with different wettability reagents. The higher the wettability, the higher the affinity with paints, hard coats, adhesives, coating materials, plating, vapor deposition, and sputtering, and the adhesion is improved.
In addition, when the surface of the injection-molded body is untreated, it is 36 dyn / cm.
(3) Hard coat adhesion:
When a hard coat of Momentive UVHC3000K is applied and cured, a cut is made in a grid pattern with a cutter knife from the top of the hard coat, and the cellophane tape is peeled off after being adhered with a cellophane tape. The proportion remaining without peeling was measured. A remaining ratio of 80% or more was judged as “pass”.
(4) Molecular weight reduction:
For the untreated molded product and the molded product after irradiation with ultraviolet rays, the viscosity average molecular weight was measured, and the difference was calculated. When the molecular weight drop exceeds 1500, it is judged that the polycarbonate resin is significantly deteriorated.
(5) Release property:
When the plastic material injection-molded product is released from the mold, it is determined whether the molded product is deformed. Judge as "Evil".

The results are shown in Tables 1 to 4.

As is apparent from Tables 1 to 4, the ultraviolet irradiation methods described in Examples 1 to 6 of the present invention are excellent in wettability and hard coat adhesion, have little molecular weight reduction, and maintain the original characteristics of plastic. ing.
However, in the methods of Comparative Examples 1 to 3, the wettability is not sufficiently improved, the adhesion of the hard coat is poor (Comparative Example 1), or the molecular weight is greatly reduced (Comparative Examples 2 and 3). It is not preferable because the original characteristics of the plastic such as deterioration of the appearance and the like are impaired. Further, the method of Comparative Example 4 is not preferable because it does not contain a release agent, so that the release property is poor and the moldability is deteriorated. Furthermore, in the method of Comparative Example 5, since the ultraviolet ray is not irradiated, the adhesion of the hard coat is extremely poor.

Claims (5)

  The surface of the plastic material injection molded body is irradiated with ultraviolet energy of 400 to 700 kJ / mol, and the temperature of the surface of the plastic material injection molded body is [glass transition temperature of plastic material (Tg) −15 ° C.] or lower and 105 ° C. or higher. The modified layer is formed with a thickness of 1 to 500 nm from the surface of the injection-molded body by irradiation so that the surface becomes, and then the surface of the modified layer is subjected to a hard coat surface treatment. Manufacturing method of material injection-molded body.   The method for producing a plastic material injection-molded article according to claim 1, wherein the plastic material injection-molded article contains 0.001 to 5% by mass of a release agent.   The method for producing a plastic material injection-molded article according to claim 1 or 2, wherein the ultraviolet energy is irradiated using an ultraviolet lamp whose tube wall temperature is adjusted to 30 to 60 ° C or lower. The method for producing a plastic material injection-molded body according to any one of claims 1 to 3 , wherein the plastic material molded body has a shape having at least a curved surface. The method for producing a plastic material injection-molded article according to any one of claims 1 to 4 , wherein the plastic material is an aromatic polycarbonate resin.