METHOD FOR MODIFYING THE SURFACE OF POLYCARBONATE RESIN

Abstract: A polycarbonate resin of a copolymer of diethyleneglycol bis(allyl carbonate) with a polymer of glycidyl acrylate and glycidyl methacrylate, and occasionally a copolymerizable compound can be easily modified with active amine at its surface, and the surface-modified copolymer of diethylene glycol bis(allyl carbonate) with glycidyl acrylate or methacrylate can be easily dyed with acid dye in a sharp color tone and can be used in an optical instrument demanded to have a high vividness of color.

Description: The present invention relates to a method for modifying the surface of polycarbonate resin, particularly, the surface of diethylene glycol bis(allyl carbonate) copolymer resin. Diethylene glycol bis(allyl carbonate) copolymer resin (hereinafter referred to as ADC resin) is a transparent and easily polishable thermosetting resin having excellent optical properties, impact resistance, solvent resistance, heat resistance and dyeability, and is used as a lens for glasses and the like (Kogyo Zairyo, Vol. 25, No. 3, pages 35-37 (1977), and US-A-2,370,565). ADC resin is different from polymethacrylate resin and can be easily dyed in the optician shop (Kindai Megane, 1977, May, pages 118-129). However, the dye capable of being used effectively in the dyeing in the optician shop is limited to a disperse dye, and moreover the disperse dye solution must be used in a high temperature of at least 90°C. Moreover, ADC resin is generally produced by a method, wherein diethylene glycol bis(allyl carbonate) monomer is poured into a mold together with a polymerization initiator, the mold is placed in a polymerization incubator, and the diethylene glycol bis(allyl carbonate) monomer is polymerized for 10-20 hours according to a particular temperature pattern depending upon the properties of the aimed ADC resin. During this polymerization reaction, the reaction mass shrinks by about 14%, and therefore the material of the gasket and the shape of the mold are important. That is, when the temperature pattern at the polymerization is rough or the shape of the mold is complicated, cracks are formed in the resulting ADC resin due to the shrinkage of the reaction mass, and hence the yield of ADC resin is low and further the surface of the resulting ADC resin is not smooth (Kagaku to Kogyo, Vol. 36, No. 11, pages 794-796(1983)). In order to obviate these drawbacks, diethylene glycol bis(allyl carbonate) monomer is polymerized together with its oligomer previously formed or is polymerized together with other polymer dissolved therein. ADC resin has not hitherto been able to be dyed with an acid dye. When ADC resin is dyed with a commonly used disperse dye, the dyed ADC resin absorbs not only a light having a specific wavelength, but also lights having wavelengths in the vicinity of the specific wavelength. Therefore, the ADC resin dyed with a disperse dye has a broad transmittance curve. Such dyed resin is not satisfactory to be used in an industrial instrument demanded to have a high vividness of color. Particularly, liquid crystal is recently used in the OA instrument and indicator, and hence the colored sheet or dyed sheet to be used in these instruments is demanded to have a sharp transmittance curve. DE-B-1,283,524 and related US-A-3,518,040 discloses the reaction of a polycarbonate structure with a primary or secondary amine having no amino group attached directly to an aromatic nucleus to form urethane moities on the surface of the polycarbonate structure. The inventors have made various investigations and experiments, and found out that an ADC resin having excellent dyeability and being able to be dyed with acid dye can be obtained by modifying the surface of the ADC resin, and accomplished the present invention. The present invention provides a method for modifying the surface of an ADC resin so as to be dyed with acid dye. In general, the dyeing with acid dye results in a dyed product having a sharp transmittance curve more easily than the dyeing with disperse dye. That is, the present invention gives a dyeability to an ADC resin so as to be dyed with acid dye and to obtain easily a dyed product having excellent optical properties. One of the features of the present invention lies in a method for modifying the surface of a polycarbonate resin with ammonia, a primary amine or a secondary amine characterised in that the amine has an active hydrogen atom, and the polycarbonate resin comprises a copolymer of 99-50% by weight of component (A) and 1-50% by weight of component (B), wherein said component (A) is diethylene glycol bis(allyl carbonate), and said component (B) is a polymer containing 2-100% by weight of glycidyl acrylate monomer units or glycidyl methacrylate monomer units, the monomer units being either methacrylate or vinyl monomer units, and the resulting polycarbonate resin contains 1-50 wt.% of glycidyl acrylate or glycidyl methacrylate monomer units. Another feature of the present invention lies in a method for modifying the surface of a polycarbonate resin, characterised in that the polycarbonate resin consists of a copolymer of 99-50% by weight of component (A), 1-50% by weight of component (B) and at least one of components (C) and (D) the total amount of components (C) and (D) being 0-49% by weight, said component (C) being a reactive methacrylate, vinyl, or polyfunctional monomer copolymerizable with component (A) or (B), and said component (D) being a polymer which can be dissolved or dispersed in component (A), (B) or (C). As component (A) to be used in the present invention, there can be used commercially available ordinary diethylene glycol bis(allyl carbonate). Component (A) is used in an amount of 99-50% by weight based on the total amount of the mixture of components (A) and (B), or components (A), (B) and at least one of (C) and (D). When the amount of component (A) is less than 50% by weight, the resulting copolymer is poor in the characteristic properties, such as transparency, optical properties, impact resistance, solvent resistance, heat resistance, dyeability and the like, inherent to the compound of component (A), and even when the amount of component (A) is more than 99%, the resulting copolymer has not remarkably improved dyeability. As component (B), there can be used polymers containing 2-100% by weight of glycidyl acrylate monomer units or glycidyl methacrylate monomer units. As the monomer to be used together with glycidyl acrylate or glycidyl methacrylate in component (B), there can be used linear alkyl(C: 1∼22) (meth)acrylates, (hereinafter, the term "(meth)acrylate" means acrylate or methacrylate), such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate and the like; branched alkyl(C: 3∼18) (meth)acrylates, such as 2-ethylhexyl (meth)acrylate, isostearyl (meth)acrylate and the like; cyclic alkyl(C: 3∼10) (meth)acrylates, such as cyclohexyl (meth)acrylate and the like; hydroxyalkyl(C: 2∼10) (meth)acrylates, such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate and the like; mono- or di-(meth)acrylates of a polyalkylene glycol, such as diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol or the like, which is a condensation product of 2-100 mols of alkylene glycols having 2-4 carbon atoms; and vinyl monomers, such as vinyl toluene, vinyl acetate, vinyl propionate, acrylonitrile, methacrylonitrile, vinyl chloride, ethylene, propylene, butadiene, acrylamide, methacrylamide, vinylpyrolidone and the like. The molecular weight of the polymer to be used as component (B) is not particularly limited, but the polymers having a weight average molecular weight of about 1,000-1,000,000 are generally used. Component (B) is used in an amount of 1-50% by weight, preferably 5-30% by weight, based on the total amount of the mixture of components (A) and (B), or components (A), (B) and at least one of (C) and (D) under a condition that the resulting polycarbonate resin contains 1-50% by weight, preferably 5-30% by weight, of glycidyl acrylate or glycidyl methacrylate monomer units. When the amount of component (B) is larger than 50% by weight, the resulting polycarbonate resin is poor in the physical properties. Moreover, a polycarbonate resin having a content of glycidyl acrylate or glycidyl methacrylate monomer units lower than 1% by weight is very poor in the dyeability, and a polycarbonate resin having a content of glycidyl acrylate or methacrylate monomer units higher than 50% by weight is poor in the mold releasing property, optical property, solvent resistance and the like. Therefore, a polycarbonate resin having a content of glycidyl acrylate or methacrylate monomer units lower than 1% by weight or higher than 50% by weight is not used in the present invention. As component (C), there can be used (meth)acrylates of alkyl alcohols or aryl alcohols, for example, linear alkyl(C: 1∼22) (meth)acrylates, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate and the like; branched alkyl(C: 3∼18) (meth)acrylates, such as 2-ethylhexyl (meth)acrylate, isostearyl (meth)acrylate and the like; cyclic alkyl(C: 3∼10) (meth)acrylates, such as cyclohexyl (meth)acrylate and the like; hydroxyalkyl(C: 2∼10) (meth)acrylates, such as hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate and the like; mono- or di-(meth)acrylates of a polyalkylene glycol, such as diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol or the like, which is a condensation product of 2-100 mols of alkylene glycols having 2-4 carbon atoms; and active vinyl monomers, such as styrene, vinyltoluene, vinyl acetate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinylpyrolidone and the like. Further, as component (C), there can be used polyfunctional monomers, such as di-(meth)acrylate of polyoxyalkylene bisphenol A, (meth)acrylate of trimethylolpropane, (meth)acrylate of pentaerythritol or dipentaerythritol, and the like. As component (D), there can be used homopolymers or copolymers of the monomers used in the above described component (C), and further commercially available polymers, such as polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, polycarbonate, polyethylene, polypropylene, polybutadiene and the like, which can be dissolved or dispersed in the diethyleneglycol bis(allyl carbonate) monomer of component (A), in the compounds of component (B) or in the copolymerisable vinyl monomer of component (C). Component (D) may be used by directly dissolving or dispersing in components (A), (B) and/or (C) or may be used by previously dissolving in other solvent, adding the resulting solution of component (D) to components (A), (B) and/or (C), and then distilling off the solvent. Components (C) and (D) are used alone or in admixture in a total amount of components (C) and/or (D) of 0-49% by weight, preferably 0-20% by weight, based on the total amount of the mixture of components (A), (B) and at least one of (C) and (D) in view of the characteristic properties of the resulting ADC resin. In the production of the ADC resin according to the present invention, given amounts of components (A) and (B), or components (A), (B) and at least one of (C) and (D) are mixed depending upon the use purpose of the resulting ADC resin, and the resulting mixture is heated and polymerized. As the polymerization catalyst, there are used diisopropyl peroxydicarbonate, benzoyl peroxide, dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexene and other polymerization catalysts. These polymerization catalysts are used in an amount of 1-5% by weight based on the total amount of the mixture of components (A) and (B), or components (A), (B) and at least one of (C) and (D). The polymerization temperature is varied depending upon the decomposition temperature of the polymerization catalyst, but is generally within the range of from room temperature to about 130°C. The polymerization time is varied depending upon the shape, thickness, dimension and the like of the resulting ADC resin, but is generally within the range of about 2-24 hours. In the conventional methods, unless a multistage heating pattern is used with respect to the polymerization temperature and time, the reaction mass shrinks during the polymerization reaction to form cracks in the resulting ADC resin, and hence the yield of the resin is decreased and an ADC resin having a smooth surface is not obtained. However, according to the present invention, since a polymer is used as component (B), the polymerization temperature and time can be relatively easily selected so as to obtain an ADC resin in a high yield. Moreover, an ADC resin having a flat sheet shape, rod shape, cylindrical shape having a semicircular cross-section, concave or convex lens shape or the like can be obtained by selecting properly the mold, into which the ADC resin is poured. The surface of the resulting ADC resin is modified by using an amine having an active hydrogen atom. The amines having an active hydrogen atom include amines having the following general formulae (I) and (II): wherein R₁ and R₂ may be same or different, and represent hydrogen atoms, linear or branched alkyl groups having 1-8 carbon atoms, alkanol groups having 3-8 carbon atoms, residues of alicyclic or aromatic compound having 3-8 carbon atoms, and residues of a compound having 2-10 atoms in the total number of carbon and nitrogen atoms, and where R₃ represents a residue of a compound having 2-10 atoms in the total number of carbon and nitrogen atoms. These amines include ammonia, linear alkylamines, such as monomethylamine, dimethylamine, monoethylamine, diethylamine, monopropylamine, dipropylamine, monobutylamine, dibutylamine, monohexylamine, dihexylamine, monooctylamine, dioctylamine and the like; branched alkylamines, such as monoisopropylamine, diisopropylamine, mono-2-ethylhexylamine, di-2-ethylhexylamine and the like; alkanolamines, such as monoethanolamine, diethanolamine and the like; cyclohexylamine, aniline, ethylenediamine, hexamethylenediamine, triethylenetetramine, phenylenediamine, piperazine, piperidine, pyrrole, imidazole and the like. The modification of the surface of ADC resin by an amine having an active hydrogen atom is carried out by a process, wherein the ADC resin is immersed in the amine itself or in a solution of the amine, and treated therein at a temperature of 50-100°c for 1-180 minutes to react the glycidyl group present in the resin surface with the amine. The amine can be used in the form of a solution of the amine in water or in a solvent depending upon the property of the amine. In this case, it is preferable that the concentration of amine in the solution is at least 25% by weight. As the solvent, there can be used hydrocarbons, such as cyclohexane, benzene, toluene and the like; alcohols, such as ethanol, n-propanol, n-butanol, n-hexanol, cyclohexanol, octanol and the like; ketones, such as methyl ethyl ketone, methyl butyl ketone and the like; polyhydric alcohols and their derivatives, such as ethylene glycol, diethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol monoacetate, ethylene glycol diacetate and the like; and other solvents. The resulting surface-modified ADC resin can be easily dyed with an ordinary acid dye. For example, the surface-modified ADC resin can be easily dyed by treating the resin in a dye solution containing an acid dye and a dyeing assistant of at least one of ammonium acetate, glacial acetic acid, formic acid, sodium sulfate and a surfactant at a bath temperature of 50-100°C for 1-180 minutes. The acid dyes are, for example, Kayakalan Orange RL, Kayacyl Rubinol 3GS, Kayanol Blue NR, Kayalon Navy Blue NB-E, which are sold by Nippon Kayaku Co., Ltd., and the like. Moreover, in the present invention, a translucent or opaque ADC resin, which can be dyed in a vivid color, can be obtained by selecting properly the polymer or monomer to be copolymerized with diethylene glycol bis(allyl carbonate) depending upon the purpose. Further, in the present invention, additives, such as antioxidant, ultraviolet ray absorbent, mold releasing agent, pigment, organic or inorganic filler and the like, can be added to the mixture of the components at the copolymerization so as to obtain an ADC resin containing these additives depending upon the purpose. The following examples are given for the purpose of illustration of this invention and are not intended as limitations thereof. Example 1 In 90 g of diethylene glycol bis(allyl carbonate) (trademark: CR-39, sold by PPG Industries, Inc.) was dissolved 10 g of a homopolymer (weight average molecular weight: 1,500) of glycidyl methacrylate and then 3 g of benzoyl peroxide was added to the solution, and the resulting mixture was homogeneously mixed. A polyvinyl chloride gasket having a diameter of 2 mm was interposed between a pair of previously cleaned glass plates (220mm length x 180mm width x 6mm thickness), and was fixed between them by means of a double clip to form a mold. The above obtained homogeneous mixture was poured into this mold and polymerized in an incubator according to a polymerization schedule, wherein the mixture was kept at 70°C for 13 hours and then kept at 115°C for 2 hours. Then, the cured product was taken out from the mold, and a test piece of 50 mm square was cut out from the cured product. This test piece was treated at 70°C for 30 minutes in 100% monoethanolamine to obtain a surface-modified product. Into water were added 0.05 g of Kayanol Blue NR (acid dye, sold by Nippon Kayaku Co., Ltd.), 0.1 g of sodium sulfate 10 hydrate and 0.15 g of glacial acetic acid, and the total amount of the resulting solution was made up to 100 mℓ. The solution was heated up to 90°C, and the above described surface-modified test piece was put into the heated solution and dyed therein for 5 minutes under stirring. After dyeing, the dyed test piece was taken out from the solution, washed with water and then dried. When the transmittance of the dyed test piece was measured within the wavelength range of 400-700 nm by means of a spectrophotometer, the following result was obtained. Wavelength (nm) Transmittance (%) 400 20 450 63 500 10 550 0 600 0 700 50 It was ascertained from the above obtained result that the cured product was satisfactorily dyed. Examples 2-11 and Comparative examples 1-4 Polymerizations, amine treatments and dyeings were carried out in the same manners as described in Example 1. The raw materials, treating conditions and obtained results are shown in Table 1 together with those of Example 1. In Comparative example 2, the amount of component (A) is small, and therefore although a copolymer having a smooth surface was obtained in the polymerization, the copolymer was erroded at its surface during the amine treatment, and was not able to be finished into a smooth surface. The symbols indicating the components of copolymer in Table 1 are as follows. According to the present invention, active groups to react with acid dye can be derived from the reaction of the epoxides of glycidyl (meth)acrylate with the amine, and introduced into only the surface of an ADC resin without decreasing its physical properties. The surface-modified ADC resin according to the present invention can be dyed with not only disperse dye, but also acid dye. Therefore, various kinds of dyes can be used, and a color tone can be selected from wide range, and hence the ADC resin can be used in a wide field. Moreover, since a dyed product having a sharp transmittance curve can be easily obtained, the dyed product can be satisfactorily used in industrial instruments demanded to have a high vividness of color. Accordingly, the present invention is very valuable in industry.

Claims: A method for modifying the surface of a polycarbonate resin with ammonia, a primary amine or a secondary amine characterised in that the amine has an active hydrogen atom, and the polycarbonate resin comprises a copolymer of 99-50% by weight of a component (A) and 1-50% by weight of component (B), wherein said component (A) is diethylene glycol bis(allyl carbonate), and said component (B) is a polymer containing 2-100% by weight of glycidyl acrylate monomer units or glycidyl methacrylate monomer units, the comonomer units being either methacrylate or vinyl monomer units, and the resulting polycarbonate resin contains 1-50 wt.% of glycidyl acrylate or glycidyl methacrylate monomer units. A method according to claim 1, characterised in that the amine having an active hydrogen atom is one of amines represented by the following general formulae (I) and (II): wherein R₁ and R₂ may be same or different and represent hydrogen atoms, linear or branched alkyl groups having 1-8 carbon atoms, alkanol groups having 1-8 carbon atoms, residues of alicyclic or aromatic compounds having 3-8 carbon atoms, or residues of compounds having 2-10 atoms in the total number of carbon and nitrogen atoms, and wherein R₃ represents a residue of a compound having 2-10 atoms in the total number of carbon and nitrogen atoms. A method for modifying the surface of a polycarbonate resin, according to claim 1 characterised in that the polycarbonate resin consists of a copolymer of 99-50% by weight of component (A), 1-50% by weight of component (B) and at least one of components (C) and (D) the total amount of components (C) and (D) being 0-49% by weight, said component (C) being a reactive methacrylate, vinyl, or polyfunctional monomer copolymerizable with component (A) or (B), and said component (D) being a polymer which can be dissolved or dispersed in component (A), (B) or (C).

Inventors: ENOMOTO, HIROYUKI, HAYASAKI, YASUSHI, KOBASHI, RIKIZO, TAKASE, SHIGEYUKI
Applicants: NIPPON OIL AND FATS COMPANY, LIMITED, PPG INDUSTRIES, INC.
Application year: 1988
Main classification: C08J7
IPC codes: D06P3, C08J7, D06P5