JP5286654B2 - Heat resistant printing ink - Google Patents

Description

  The present invention relates to a printing ink having excellent heat resistance.

  Conventionally, a film with decorative printing on the surface is attached to the mold, and the molten resin is injected into the mold to the film printing surface, and the film with decorative printing on the resin surface is integrated. A method of obtaining various printed injection molded products having curved surfaces, irregularities, or flat surfaces by injection molding (hereinafter referred to as insert molding) is used. For example, it is applied to injection moldings such as various meter panels and sunroofs of automobiles, edges of window glass, mobile phone housings, AV product housings, display parts of portable terminal devices and copiers, and miscellaneous goods.

  The printing ink for the decoratively printed film is mainly composed of a solvent, a dye / pigment, and a binder resin. The printing ink removes the solvent by printing on the film and then drying to fix the dye / pigment to the binder resin, and at the same time the film and the binder resin are in close contact with each other, whereby a decorative printed film is obtained. The decoratively printed film is required to have heat resistance that does not cause bleeding or blurring on the printed surface even when it is in contact with the molten resin or held in a heated mold during insert molding.

Since the heat resistance depends on the heat resistance of the binder resin, a heat-resistant printing ink using a special polycarbonate resin having excellent heat resistance and good solvent solubility as a binder resin has been developed (Patent Document 1, Patent Document) 2).

These binder resins have good heat resistance, are well soluble in various solvents, and are suitable as binder resins for heat-resistant printing inks. However, in recent years, the speed of the injection molding cycle in insert molding is often increased, and a higher polymer type resin for injection molding is often used. In this case, it is necessary to further increase the temperature of the molten resin. In particular, the temperature of the molten resin that comes into contact with the film may be 320 ° C. or more. In such a case, the heat resistance is insufficient even with the conventional binder resin, and printing defects such as ink flow may occur. was there.
JP-A-8-3502 Japanese Patent Laid-Open No. 2001-19885

  An object of the present invention is to provide a heat-resistant printing ink binder resin and a binder resin that are excellent in heat resistance, and that can provide a decorative molded product with good appearance that does not cause ink flow upon contact with a hot melt resin during insert molding. It is in providing the heat-resistant printing ink used.

As a result of intensive studies to solve the above problems, the present inventors have found that heat-resistant printing inks using a polycarbonate resin having a specific structural unit as a binder resin have good printability and are heat-melted after printing. It has been found that the resin has heat resistance that does not cause ink flow even in contact with a resin, and the present invention has been completed.
That is, heat resistance printing inks shown below, and is intended to provide a decorative method for producing a resin molded article using the ink.

(1) A heat-resistant printing ink comprising a polycarbonate resin having a structural unit represented by the following general formula (1) .


(In the formula, R _{1 to} R ₂₆ are hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and 2 carbon atoms. An alkenyl group having 5 to 5 carbon atoms or an aralkyl group having 7 to 17 carbon atoms, and when these groups have carbon, these carbons include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, (It may have a substituent selected from fluorine, chlorine, bromine, and iodine.)
(2) The heat resistant printing ink according to (1), wherein R _{1 to} R ₂₆ in the formula (1) are hydrogen .
(3) The heat resistant printing ink according to (1), wherein R ₁ in the formula (1) is a methyl group at the meta position, and R _{2 to} R ₂₆ are hydrogen.

(4) The heat resistant printing ink according to any one of (1) to (3), wherein the intrinsic viscosity of the polycarbonate resin is 0.3 to 2.0 dl / g.
(5) The heat resistant printing ink according to any one of (1) to (4) , which contains a non-halogen organic solvent as an ink adjusting solvent.
(6) A decorative resin molding characterized by inserting a film printed with the ink according to any one of (1) to (5) into a mold and then injecting a heat-melted resin into the mold. Product manufacturing method.
(7) The method for producing a decorated resin molded article according to ( 6 ), wherein the heat-melted resin is a polycarbonate resin other than the polycarbonate resin represented by the general formula (1).
(8) The temperature of the heat-melted resin is 320 ° C. or higher.
(6) The manufacturing method of the decorative resin molded product of (7) description.

  The decorative printing film using the heat-resistant printing ink of the present invention maintains the adhesiveness as compared with the one using the conventional heat-resistant printing ink, and exhibits excellent heat resistance. It is suitable for an injection molded product in which insert molding is performed. It is used for insert injection molding products such as housings and operation panels for various meter panels such as automobiles, mobile terminal devices including mobile phones, AV equipment, small game machines and home appliances, and designs for toys and sundries. It is suitable as a heat resistant printing ink for decorative printing films.

  The polycarbonate resin, which is a binder resin for heat-resistant printing inks of the present invention, can be produced by reacting a bisphenol that induces the structural unit (1) with a carbonate ester-forming compound. Known methods used in the production of polycarbonate derived from bisphenol A, such as direct reaction of bisphenols with phosgene (phosgene method), or transesterification of bisphenols with bisaryl carbonate (transesterification method) ) And the like.

  Bisphenols that derive the structural unit represented by the general formula (1), which is a raw material monomer of the polycarbonate resin, are compounds represented by the following general formula (2).

_(Wherein, R 1 _{to R 26} represents the same group as in formula (1).)

  Specifically, 1,1-bis (4-hydroxyphenyl) cyclododecane, 1,1-bis (4-hydroxy-3-methylphenyl) cyclododecane, 1,1-bis (4-hydroxy-3-phenylphenyl) ) Cyclododecane, 1,1-bis (4-hydroxy-3-t-butylphenyl) cyclododecane, 1,1-bis (4-hydroxy-3-sec-butylphenyl) cyclododecane, 1,1-bis ( 4-hydroxy-3-allylphenyl) cyclododecane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclododecane, 1,1-bis (4-hydroxy-3-fluorophenyl) cyclododecane, 1,1-bis (4-hydroxy-3-chlorophenyl) cyclododecane, 1,1-bis (4-hydroxy-3-bromophenyl) si Rhododecane, 7-ethyl-1,1-bis (4-hydroxyphenyl) cyclododecane, 5,6-dimethyl-1,1-bis (4-hydroxyphenyl) cyclododecane, 1,1-bis (2-hydroxyphenyl) ) Cyclododecane and the like are exemplified. These can be used in combination of two or more. Among these, 1,1-bis (4-hydroxyphenyl) cyclododecane and 1,1-bis (4-hydroxy-3-methylphenyl) cyclododecane are particularly preferable.

  In addition to the bisphenols represented by the formula (2), the raw material monomer can be used in combination with the following bisphenols to form a copolymerized polycarbonate. Specifically, 4,4′-biphenyldiol, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxy-3-methylphenyl) ) Sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) ketone, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4 -Hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) cyclohexane 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4 Hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, bis (4-hydroxyphenyl) diphenylmethane, 2,2-bis (4-hydroxy-3-allyl) Phenyl) propane, 3,3,5-trimethyl-1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxy-2-methyl-5-tert-butylphenyl) -2-methyl Propane, 9,9-bis (4-hydroxy-3-ethylphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 9,9-bis (4-hydroxyphenyl) fluorene, α , Ω-bis [3- (o-hydroxyphenyl) propyl] polydimethyldiphenyl random copolymer siloxane, α, ω-bi [3- (o-hydroxyphenyl) propyl] polydimethylsiloxane, 4,4 ′-[1,4-phenylenebis (1-methylethylidene)] bisphenol, 4,4 ′-[1,3-phenylenebis (1 -Methylethylidene)] bisphenol and the like. These can be used in combination of two or more. Among these, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, and 1,1-bis (4-hydroxyphenyl) cyclohexane are particularly preferable. preferable.

The bisphenol represented by the formula (2) is preferably used in an amount of 50 mol% or more, more preferably 90 mol% or more, of all bisphenols used.

  Examples of the carbonic acid ester forming compound include phosgene, bisallyl carbonate such as diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, and dinaphthyl carbonate. Two or more of these compounds can be used in combination.

  In the phosgene method, bisphenol represented by the formula (2) is reacted with phosgene, usually in the presence of an acid binder and a solvent. Examples of the acid binder include pyridine and alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and examples of the solvent include methylene chloride and chloroform. Further, a catalyst such as a tertiary amine such as triethylamine or a quaternary ammonium salt is used to accelerate the polycondensation reaction, and phenol, pt-butylphenol, p-cumylphenol are used for adjusting the degree of polymerization. It is preferable to add a monofunctional compound such as a long-chain alkyl-substituted phenol as a molecular weight regulator. If desired, a small amount of an antioxidant such as sodium sulfite or hydrosulfite, or a branching agent such as phloroglucin or isatin bisphenol may be added. The reaction is usually in the range of 0 to 150 ° C, preferably 5 to 40 ° C. While the reaction time depends on the reaction temperature, it is generally 0.5 min-10 hr, preferably 1 min-2 hr. Further, during the reaction, it is desirable to maintain the pH of the reaction system at 10 or more.

  On the other hand, in the transesterification method, bisphenol of the formula (2) and bisaryl carbonate are mixed and reacted at high temperature under reduced pressure. The reaction is usually carried out at a temperature in the range of 150 to 350 ° C., preferably 200 to 300 ° C., and the degree of vacuum is preferably 1 mmHg or less at the end, and phenols derived from the bisaryl carbonate produced by the transesterification reaction Is distilled out of the system. The reaction time depends on the reaction temperature, the degree of vacuum, etc., but is usually about 1 to 4 hours. The reaction is preferably carried out in an inert gas atmosphere such as nitrogen or argon. Moreover, you may react by adding a molecular weight regulator, antioxidant, and a branching agent as needed.

The polycarbonate resin of the present invention needs to maintain the necessary solvent solubility and strength as a binder resin for heat-resistant printing ink in a well-balanced manner. If the intrinsic viscosity of the binder resin is too low, the strength is insufficient and the intrinsic viscosity is low. Is too high, the solvent solubility decreases and the ink viscosity increases, and the printability decreases. The intrinsic viscosity is preferably in the range of 0.3 to 2.0 dl / g, more preferably in the range of 0.35 to 1.5 dl / g.

  The heat-resistant printing ink of the present invention is produced by dissolving the binder resin and dye / pigment in a desired solvent. Examples of the dye / pigment used in the heat-resistant printing ink of the present invention include, for example, anthraquinone and naphthoquinone dyes, inorganic pigments such as titanium oxide, carbon black, calcium carbonate, and metal particles, azo pigments, and phthalocyanine pigments. Organic pigments and the like. These dyes / pigments are present together with the binder resin in a dissolved or dispersed state in the ink.

  As the solvent for ink preparation, non-halogen organic solvents are preferable, for example, aromatic hydrocarbons such as toluene and xylene, cyclic ketones such as cyclohexanone, cyclopentanone and isophorone, and cyclic ethers such as tetrahydrofuran and dioxane. , Dimethylformamide, dimethyl sulfoxide and the like. Among them, dioxane, tetrahydrofuran, toluene, xylene, cyclohexanone and isophorone are preferable. Moreover, a solvent may be used independently or may be used with 2 or more types of mixed solvents. Furthermore, for the purpose of improving dye / pigment dispersibility, coating properties, drying properties, etc., alcohols such as methanol and ethanol, acyclic ketones such as methyl ethyl ketone and acetone, esters such as ethyl acetate, methyl acetate and methoxypropyl acetate, Solvents or poor solvents such as aliphatic hydrocarbons such as cyclohexane and n-heptane, alkylene glycols and derivatives thereof, and oils such as silicone oil and soybean oil can be used in combination.

  In addition to the binder resin and dye / pigment, the heat-resistant printing ink contains organic and inorganic fine particles, release agents, antioxidants, plasticizers, dispersants, infrared absorbers, antistatic agents, and UV absorbers as necessary. Agents, antifoaming agents, leveling agents and the like may be added.

  Moreover, although the compounding quantity of binder resin in ink is influenced by intrinsic viscosity or solvent solubility, 1 to 70 weight% is preferable and 5 to 50 weight% is more preferable. When the concentration of the binder resin is within this range, the solvent solubility and the ink application property are well balanced, and the workability is improved.

  In the present invention, the heat-resistant printing ink is applied to a base film and used for insert molding decoration. The resin film used for the base film is a thermoplastic resin film, specifically a polycarbonate resin film, a polyester resin film, a polyamide resin film, a heat-resistant polyolefin resin film, a polycarbonate / polyester blend film, a polycarbonate / ABS blend film. In particular, a polycarbonate resin film and a polycarbonate / polyester blend film are preferably used because of excellent transparency, heat resistance, mechanical strength, and the like. These resin films usually have a thickness of 0.01 to 2 mm, preferably 0.1 to 0.5 mm.

  Examples of the method for applying the heat-resistant printing ink of the present invention to the base film include screen printing, gravure printing, flexographic printing, etc., but the ink layer to be applied has a wide film thickness range, and the ink layer can be thickened. Screen printing is particularly preferable because it can be performed. The coated ink is dried by natural standing, cold / hot air blowing, infrared irradiation, heat baking, ultraviolet irradiation or the like to obtain a dried printed surface.

  The heat-resistant printing ink of the present invention can be suitably used as an ink for a decorative printing film in insert molding for the purpose of decorating a thermoplastic resin.

Examples of the resin molded by insert molding include polystyrene, polyester, polycarbonate, polyarylate, polysulfone, and nylon. Among them, the decorative print film using the heat-resistant printing ink of the present invention is a printed part pattern after insert molding when decorating a polycarbonate resin or polycarbonate / polyester blend resin formed at a high temperature, particularly at 320 ° C. or higher. No blur or blur is seen, and the adhesiveness of the printed part is excellent.

Hereinafter, the present invention will be described in detail with reference to examples.

<Example 1>
In 1100 ml of 5 w / w% aqueous sodium hydroxide solution, 140.8 g (0.4 mol) of 1,1-bis (4-hydroxyphenyl) cyclododecane (hereinafter abbreviated as “BPCD”: manufactured by Taoka Chemical Co., Ltd.) and hydrosal 0.1 g of phyto was dissolved.
To this, 500 ml of methylene chloride was added and stirred, while maintaining at 15 ° C., 60 g of phosgene was blown in over 60 minutes.
After completion of phosgene blowing, 1.67 g of pt-butylphenol (hereinafter abbreviated as “PTBP”: Dainippon Ink & Chemicals, Inc.) as a molecular weight regulator was added and stirred vigorously to emulsify the reaction solution. 0.4 ml of triethylamine was added, and the mixture was stirred at 20 to 25 ° C. for about 1 hour for polymerization.
After completion of the polymerization, the reaction solution was separated into an aqueous phase and an organic phase, the organic phase was neutralized with phosphoric acid, and washing with water was repeated until the conductivity of the previous solution (aqueous phase) became 10 μS / cm or less. The obtained polymer solution was dropped into warm water maintained at 45 ° C., and the solvent was removed by evaporation to obtain a white powdery precipitate.
The obtained precipitate was filtered and dried at 105 ° C. for 24 hours to obtain a polymer powder.
The intrinsic viscosity at 20 ° C. of a solution having a concentration of 0.5 g / dl using methylene chloride as a solvent of this polymer was 0.48 dl / g. The results obtained polymer was analyzed by infrared absorption spectrum, absorption by carbonyl group at the position in the vicinity of 1770 cm ^-1, observed absorption by ether bond position near 1240 cm ^-1, it is polycarbonate resin having a carbonate bond Was confirmed.
30 parts by weight of the obtained polycarbonate resin as a binder resin, 10 parts by weight of anthraquinone Plast Red 8370 (Arimoto Chemical Co., Ltd.) as a dye, 100 parts by weight of cyclohexanone and 30 parts by weight of dioxane as a solvent are mixed for printing. The ink was adjusted. Next, the printing ink is screen-printed on one side of a commercially available polycarbonate film (Mitsubishi Gas Chemical Co., Ltd .; Iupilon FE-2000) having a thickness of 0.2 mm × 150 mm × 70 mm as a base film, and is heated at 100 ° C. for 2 hours. After drying, the printed film was mounted on a 2 mm thick mold of the same size, and a polycarbonate (Mitsubishi Gas Chemical Co., Ltd .; Iupilon S-2000) melted at 320 ° C. was insert molded by a vertical injection molding machine. The missing state of printing of the obtained insert-molded product was visually evaluated. Similarly, a polycarbonate melted at 330 ° C. (manufactured by Mitsubishi Gas Chemical Co., Inc .; Iupilon E-2000) was subjected to the same insert molding and visually evaluated for a print missing state.

<Example 2>
Polymerization was carried out in the same manner as in Example 1 except that PTBP was changed to 0.82 g to obtain a polycarbonate (intrinsic viscosity 0.75 dl / g). Using the obtained polycarbonate as an ink binder resin in the same manner as in Example 1, printing, molding, and evaluation were performed.

<Example 3>
Polycarbonate was polymerized in the same manner as in Example 1 except that BPCD was changed to 152 g of 1,1-bis (4-hydroxy-3-methylphenyl) cyclododecane (hereinafter abbreviated as “DMBPCD”: manufactured by Taoka Chemical Co., Ltd.). (Intrinsic viscosity 0.48 dl / g) was obtained. Using the obtained polycarbonate as an ink binder resin in the same manner as in Example 1, printing, molding, and evaluation were performed.

<Example 4>
As in Example 1, except that BPCD was changed to 126.7 g and 10.7 g of 1,1-bis (4-hydroxyphenyl) cyclohexane (hereinafter abbreviated as “BPZ”: manufactured by Taoka Chemical Co., Ltd.) was used at the same time. Polymerization was performed to obtain polycarbonate (intrinsic viscosity 0.48 dl / g). Using the obtained polycarbonate as an ink binder resin in the same manner as in Example 1, printing, molding, and evaluation were performed.

<Example 5>
Polymerization was carried out in the same manner as in Example 1 except that BPCD was changed to 133.8 g and 4.6 g of 2,2-bis (4-hydroxyphenyl) propane (hereinafter abbreviated as “BPA”: Mitsui Chemical Co., Ltd.) was used. To obtain a polycarbonate (intrinsic viscosity 0.49 dl / g). Using the obtained polycarbonate as an ink binder resin in the same manner as in Example 1, printing, molding, and evaluation were performed.

<Example 6>
Example except that BPCD was changed to 133.8 g and 5.1 g of 2,2-bis (4-hydroxy-3-methylphenyl) propane (hereinafter abbreviated as “BPC”: manufactured by Honshu Chemical Industry Co., Ltd.) was used at the same time. 1 was polymerized to obtain polycarbonate (intrinsic viscosity 0.49 dl / g). Using the obtained polycarbonate as an ink binder resin in the same manner as in Example 1, printing, molding, and evaluation were performed.

<Example 7>
Printing, molding, and evaluation were carried out in the same manner as in Example 1 except that 20 parts by weight of a cobalt blue pigment (manufactured by Bayer Corporation; Lightfast Blue 100) was used instead of the dye, and cyclohexanone was changed to 100 parts by weight of isophorone. .

<Comparative example 1>
Polymerization was carried out in the same manner as in Example 1 except that BPCD was changed to BPZ107.2 g to obtain a polycarbonate (intrinsic viscosity 0.46 dl / g). Using the obtained polycarbonate as an ink binder resin in the same manner as in Example 1, printing, molding, and evaluation were performed.

<Comparative example 2>
Polymerization was carried out in the same manner as in Example 1 except that BPCD was changed to 124 g of 3,3,5-trimethyl-1,1-bis (4-hydroxyphenyl) cyclohexane (hereinafter abbreviated as “TMBPZ”: manufactured by Honshu Chemical Industry Co., Ltd.). To obtain a polycarbonate (intrinsic viscosity 0.49 dl / g). Using the obtained polycarbonate as an ink binder resin in the same manner as in Example 1, printing, molding, and evaluation were performed.

<Comparative Example 3>
Polymerization was carried out in the same manner as in Example 1 except that BPCD was changed to 91.2 g of BPA to obtain a polycarbonate (intrinsic viscosity 0.52 dl / g). The obtained polycarbonate was used as an ink binder resin in the same manner as in Example 1, but it did not dissolve in the solvent and could not be printed with ink.

○: As a result of visually observing the insert-molded product directly under the fluorescent lamp, the ink flow could not be confirmed even when visually judged.
Δ: As a result of visually observing the insert molded product directly under a fluorescent lamp, there was unevenness due to local ink flow.
X: Ink loss could be clearly observed without observing the insert molded product directly under the fluorescent lamp.

  As an application example of the present invention, it can be used as a heat-resistant and heat-resistant printing ink for a decorative printing film, and the decorative printing film can be applied to an injection-molded product in which insert molding is performed at a high temperature. It is used for insert injection molding products such as housings and operation panels for various meter panels such as automobiles, mobile terminal devices including mobile phones, AV equipment, small game machines and home appliances, and designs for toys and sundries. It is suitable as a heat resistant printing ink for decorative printing films.

Claims (8)

A heat-resistant printing ink comprising a polycarbonate resin having a structural unit represented by the following general formula (1) .


(In the formula, R _{1 to} R ₂₆ are hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and 2 carbon atoms. -5 alkenyl group or C7-17 aralkyl group.) The heat-resistant printing ink according to claim 1, wherein R _{1 to} R ₂₆ in the formula (1) are hydrogen . The heat-resistant printing ink according to claim 1, wherein R ₁ in the formula (1) is a methyl group at the meta position, and R _{2 to} R ₂₆ are hydrogen . The heat-resistant printing ink according to any one of claims 1 to 3, wherein the polycarbonate resin has an intrinsic viscosity of 0.3 to 2.0 dl / g . The heat-resistant printing ink according to any one of claims 1 to 4 , comprising a non-halogen organic solvent as a solvent for adjusting the ink. A method for producing a decorative resin molded product, wherein the film printed with the ink according to any one of claims 1 to 5 is inserted into a mold, and then a heat-melted resin is injected into the mold. . The method for producing a decorated resin molded article according to claim 6 , wherein the heat-melted resin is a polycarbonate resin other than the polycarbonate resin represented by the general formula (1). The method for producing a decorated resin molded product according to claim 6 or 7 , wherein the temperature of the heat-melted resin is 320 ° C or higher.