JPH0512393B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a technique for improving the thermal stability of polycarbonate resins and polyester resins useful as packaging materials such as films, sheets, and bottles, or as engineering plastics. [Prior art] Polycarbonate resins and polyester resins are used in practical applications as packaging materials for products that require oxygen barrier properties such as foods, or as so-called engineering plastics for parts of machinery, appliances, and electrical equipment. . Although each of these resins has its own unique and excellent physical properties, various improvements have been made in response to recent advanced technological innovations and high demands for higher performance. As one such improvement technology, saponified ethylene-vinyl acetate copolymer has been developed to improve oxygen barrier properties, improve interlayer adhesion during the production of laminated structures, and further improve mechanical and electrical properties. It is being carried out to mix. [Problems to be Solved by the Invention] However, the inventors of the present invention have investigated that it is difficult to sufficiently improve the impact resistance, etc. of the above-mentioned composition, and such drawbacks are necessary for expanding the use of the composition. It turned out that we also had to solve the problem. The present inventors believe that the cause of this is that polyester and polycarbonate lack thermal stability in the presence of trace amounts of moisture, and that impurities, especially alkali components, present in the saponified ethylene-vinyl acetate copolymer are melt-molded. The present invention was developed based on the assumption that the catalytic action of partially thermally decomposing polyester, polycarbonate, etc. may lead to deterioration of mechanical strength such as impact strength. I have come to complete it. [Means for Solving the Problems] That is, the present invention consists of: (1) 100 parts by weight of a thermoplastic resin selected from polycarbonate resins and polyester resins; (2) ethylene content of 20 to 60 mol%; acetic acid; The saponification degree of the vinyl part is 95 mol% or more, the ash content is 1 to 20 ppm, and the alkali metal content is
A thermoplastic resin composition with good thermal stability comprising 0.1 to 1 part by weight of a saponified ethylene-vinyl acetate copolymer in an amount of 0.5 to 5 ppm. '', and its major feature is that it uses a saponified ethylene-vinyl acetate copolymer with extremely low ash and alkali metal contents. First, the thermoplastic resin of component (1) targeted by the present invention is a polycarbonate resin, a polyester resin such as polyethylene terephthalate, polybutylene terephthalate, etc. Polycarbonates are typically prepared by reaction of dihydric phenols with carbonate precursors such as phosgene or by transesterification of dihydric phenols with carbonate precursors such as diphenyl carbonate in the presence of an acid acceptor and a molecular weight modifier. manufactured by As the divalent phenol, bisphenol A is preferred. Part or all of bisphenol A may be replaced with other divalent phenols. Further, the polycarbonate may be partially branched; for example, it may be a thermoplastic randomly branched polycarbonate obtained by reacting a polyfunctional aromatic compound with a dihydric phenol or a carbonate precursor. Polyethylene terephthalate is mainly composed of terephthalic acid or dimethyl terephthalate and ethylene glycol, and is produced by the polycondensation reaction of these. Polyethylene terephthalate is also produced by replacing a portion of ethylene glycol with other glycols such as cyclohexanedimethanol. included. Polybutylene terephthalate can be produced by polycondensation of bis-(ω-hydroxybutyl)-terephthalate produced by transesterification of dimethyl terephthalate and 1,4-butanediol, or by polycondensation of terephthalic acid and 1,4-butanediol. It can be produced by any method such as a condensation reaction, a transesterification reaction of terephthalic acid or dimethyl terephthalate and 1,4-diacetoxybutane, and then polycondensation. (1) may also be polyester polycarbonate. The resin is produced, for example, by reacting a dihydroxydiaryl compound such as bisphenol A with terephthaloyl chloride in the presence of an organic solvent such as methylene chloride and an acid binder such as pyridine, and then introducing phosgene into the reaction product. A solution polymerization method in which an alkaline aqueous solution of a dihydroxydiaryl compound and a solution of terephthaloyl chloride in an organic solvent are reacted, and then phosgene is introduced into the reaction mixture to form an oligomer with a chloroformate group at the end. It is produced by an interfacial polymerization method in which an alkaline aqueous solution of the dihydroxydiaryl compound is added and polycondensed. Next, the saponified ethylene-vinyl acetate copolymer, component (2) of the present invention, will be explained. As mentioned above, the feature of the present invention is that the ash content contained in the saponified ethylene-vinyl acetate copolymer is adjusted to 1 to 20 ppm, and the alkali metal content is adjusted to 0.5 to 5 ppm. In other words, the above-mentioned saponified products are usually produced by saponifying ethylene-vinyl acetate copolymer with an alkali catalyst, but metal salts contained as impurities in the industrial water and reagents used, or alkali metal water as a saponification catalyst, Since oxides and the like remain as alkali metal acetates after the reaction, they are contained in the resin precipitated from the saponification solution. In the present invention, by controlling the amount of the metal salt within the above range, the thermal stability of the target thermoplastic resin can be improved. The ash in the present invention refers to dry saponified ethylene-vinyl acetate copolymer taken in a platinum evaporation dish,
After carbonizing using an electric heater and a gas burner, it is placed in an electric furnace at 400℃, and the temperature is gradually raised to 700℃, and then heated to 700℃.
After being completely incinerated at ℃ for 3 hours, it is taken out from the electric furnace, left to cool for 5 minutes, and then left in a desiccator for 25 minutes.The ash content is determined by measuring the ash content, and its content is 1 to 20 ppm. , preferably 1 to 10 ppm. If it exceeds 20 ppm, the mechanical strength of the obtained molded product will decrease significantly and the surface appearance will deteriorate, making it impractical. Moreover, if it is less than 1 ppm, it causes deterioration of the thermoplastic resin. Furthermore, in the present invention, in addition to limiting the above-mentioned ash content value, the alkali metal content is also limited.
It should be between 0.5 and 5 ppm, preferably between 0.5 and 3 ppm. The presence of an alkali metal in an amount exceeding this amount causes the problem of deteriorating the properties of the target thermoplastic resin, as described above. Also,
If the amount is less than 0.5 ppm, resin deterioration will occur as well. The alkali metal is determined by atomic absorption spectrometry using a solution obtained by incinerating the saponified ethylene-vinyl acetate copolymer in the same manner as described above, and then dissolving the ash in an aqueous hydrochloric acid solution under heating. The saponified product of the present invention is produced by saponifying ethylene-vinyl acetate copolymer. Powder, particles, and pellets of saponified ethylene-vinyl acetate copolymer are thoroughly washed with an acid, especially an aqueous solution of a weak acid, to remove ash and remove the ash. After removing the salts that cause alkali metals, the resin is further desirably washed with deionized water to remove the acid adhering to the resin, and then dried. As the acid, acetic acid, propionic acid, glycolic acid, lactic acid, adipic acid, azelaic acid, glitaric acid, succinic acid, benzoic acid, isophthalic acid, terephthalic acid, etc. can be used. Typically pKa (25℃)
A value of 3.5 or higher is useful. In addition, after performing the treatment with the above weak acid, and before or after washing with deionized water, further dilute strong acids such as organic acids with a pKa (at 25°C) of 2.5 or less such as oxalic acid and maleic acid, phosphoric acid, sulfuric acid, and nitric acid may be used. By treating with an aqueous solution of an inorganic acid such as hydrochloric acid, it is possible to efficiently remove the alkali metal, so it is preferable to use that solution. The saponified ethylene-vinyl acetate copolymer used in the present invention has an ethylene content of 20 to 60 mol%, preferably 25 to 55 mol%, and a degree of saponification of the vinyl acetate component of 95 mol% or more. If the ethylene content is less than 20 mol%, the compatibility with the target thermoplastic resin will decrease, while if it is more than 60 mol%, the thermal stability of the composition with the thermoplastic resin will not be sufficient. Furthermore, if the degree of saponification is less than 95 mol%, thermal stability and moisture resistance will decrease. In addition, the saponified copolymer further contains small amounts of propylene, isobutene, α-octene, α-dodecene,
Contains comonomers such as α-olefins such as α-octadecene, unsaturated carboxylic acids or their salts, partial alkyl esters, complete alkyl esters, nitriles, amides, anhydrides, and unsaturated sulfonic acids or their salts as copolymerization components. No problem. The mixing ratio of component (1) and component (2) is 100 parts by weight of (1).
(2) shall be 0.1 to 1 part by weight. If (2) is less than 0.1 part by weight, it is difficult to see the effect of mixing the saponified ethylene-vinyl acetate copolymer, while if it is more than 1 part by weight, the effect of improving thermal stability will not necessarily be noticeable depending on the amount added. Not only is it economically disadvantageous, but also the transparency decreases in applications such as sheets, films, and bottles, making it impractical. The mixture of components (1) and (2) can be melt-molded to form the desired pellets, films, sheets, containers, etc.
Manufacture molded products of arbitrary shapes such as rods and pipes. As the melt molding method, an injection molding method, an extrusion molding method, a rotational molding method, a fluidized immersion molding method, a blow molding method, etc. are adopted. The composition can be molded under almost the same conditions as when the thermoplastic resin is used alone, and the melt molding temperature varies depending on the type of thermoplastic resin, but is generally suitably 200 to 320°C. During such molding, it is of course possible to use in combination two or more types of saponified ethylene-vinyl acetate copolymers having various ethylene contents and saponification degrees for component (1). Also, during melt molding, ethylene-
In addition to the saponified vinyl acetate copolymer, plasticizers (polyhydric alcohols, etc.), stabilizers, surfactants, crosslinking substances (epoxy compounds, polyvalent metal salts, inorganic or organic polybasic acids or their salts, etc.), fillers, colorants,
Appropriate amounts of fibers (glass fibers, carbon fibers, etc.) as reinforcing agents, flame retardants, flame retardant aids, etc. can be blended. Furthermore, other thermoplastic resins can be blended in appropriate amounts, such as polyolefin, polyamide, polyvinyl chloride, polyvinylidene chloride, polyacetal,
Examples include polystyrene, ABS, polyurethane, etc. Furthermore, it is important not only to produce a single-layer molded product using the composition of the present invention, but also to coextrude it with other thermoplastic resin layers. In the case of coextrusion molding, the partner resins include low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-α-olefin (carbon number 3).
~20 α-olefins) copolymers, ethylene-acrylic acid ester copolymers, polypropylene, propylene-α-olefins (α-olefins having 4 to 20 carbon atoms)
Polyolefin resins and polyesters in a broad sense, such as olefin (olefin) copolymers, mono or copolymers of olefins such as polybutene and polypentene, and mono or copolymers of these olefins graft-modified with unsaturated carboxylic acids or esters thereof. , polyamide, copolyamide, polyvinyl chloride, polyvinylidene chloride, acrylic resin, styrene resin, vinyl ester resin, polyester elastomer, polyurethane elastomer, chlorinated polyethylene, chlorinated polypropylene, ethylene-vinyl acetate copolymer Examples include chemical substances. Furthermore, once a molded product such as a film or sheet is obtained from the composition of the present invention, it may be extrusion coated with other thermoplastic resin such as polyolefin or coated with any other base material (paper, metal foil, stretched or unstretched plastic). (film or sheet, woven fabric, non-woven fabric, wooden surface, etc.) can also be dry laminated using an adhesive. Molded products after melt molding, coextrusion molded products, and melt coated molded products may be subjected to heat treatment, cooling treatment, rolling treatment, uniaxial or biaxial stretching treatment, printing treatment, dry lamination treatment, solution or melt coating treatment, and manufacturing as necessary. Bag processing, deep drawing processing, box processing, tube processing,
Split processing etc. can be performed. [Function] The molded product obtained from the composition of the present invention can be used for foods,
Packaging materials for industrial chemicals and agricultural chemicals, general machinery parts,
It can be used in a variety of applications such as automobile, ship, and aircraft parts, optical and clock equipment parts, electrical and mechanical equipment parts, building materials, and daily necessities. [Example] Next, the composition of the present invention will be explained in more detail with reference to Examples. Hereinafter, "parts" or "%" are expressed on a weight basis unless otherwise specified. Note that water means deionized water. Preparation of saponified ethylene-vinyl acetate copolymer 1000 parts of a 40% methanol solution of an ethylene-vinyl acetate copolymer with an ethylene content of 40 mol% was placed in a pressure-resistant reactor and heated to 110° C. with stirring. Next, 40 parts of a 6% methanol solution of sodium hydroxide and 2,500 parts of methanol were continuously charged, and a saponification reaction was carried out for 2.5 hours while distilling by-product methyl acetate and excess methanol from the system, to remove the vinyl acetate component. A saponified ethylene-vinyl acetate copolymer having a saponification degree of 99.0 mol% was obtained. While adding 450 parts of 30% water-containing methanol to the saponified liquid, excess methanol was distilled off to produce a water/methanol (3/7 composition ratio) solution with a resin concentration of 39%. A water/methanol mixture of the saponified ethylene-vinyl acetate copolymer at a temperature of 50°C was passed through a nozzle with a hole diameter of 4 mm at a rate of 1.5/hour to a water/methanol mixture maintained at 5°C (mixing ratio 9). /1) It was extruded into a strand shape into a coagulation liquid tank (width 100 mm, length 4000 mm, depth 100 mm). After coagulation, a take-up roller attached to the end of the coagulation tank (linear speed 2 m/min)
After that, the strand-like material was cut with a cutter to produce white, porous pellets with a diameter of 4 mm and a length of 4 mm. Ash content 7400ppm, sodium metal content
A saponified ethylene-vinyl acetate copolymer of 4800 ppm was obtained. Next, 100 parts of the pellets were immersed in 300 parts of a 0.3 acetic acid aqueous solution, stirred at 30°C for 1 hour, and washed twice. After separating the slurry, the obtained pellets were mixed again with 300 parts of water to form a slurry and heated at 30°C.
Washing with water was repeated three times while stirring for 1 hour. The slurry was separated and dried. The saponified ethylene-vinyl acetate copolymer thus obtained had a degree of saponification of 99.0 mol%, an ash content of 6 ppm,
The sodium metal content was 2.7 ppm. In addition, a saponified ethylene-vinyl acetate copolymer with an ash content of 30 ppm and a sodium metal content of 10 ppm to be used as a control example was produced according to the above method. Furthermore, prior to washing with water in the above method, further
The ash content was 10 ppm, sodium metal
A 1.4 ppm saponified ethylene-vinyl acetate copolymer [] was obtained. Incidentally, the ash content and sodium metal were determined in accordance with the following. (Ash content) Accurately weigh approximately 80g of the dried sample, and approximately
10 g was placed in a platinum evaporating dish with constant weight and carbonized using an electric heater. After carbonization, approximately 10 g of each sample was added and the same operation was repeated. Finally, I heated it with a gas burner and baked it until there was no smoke. The platinum evaporation dish was placed in an electric furnace at about 400°C, most of it covered with a magnetic crucible lid, and the temperature was gradually raised to 700°C. After being completely incinerated by holding at 700°C for 3 hours, it was taken out from the electric furnace, left to cool for 5 minutes, and then left in a desiccator for 25 minutes, and the ash content was accurately weighed. (Sodium metal) Approximately 10 g of the dried sample was accurately weighed, placed in a platinum crucible, and incinerated in the same manner as above. 2 ml of special grade hydrochloric acid and 3 ml of pure water were placed in a platinum crucible and heated with an electric heater to dissolve them. The above solution was poured into a 50 ml volumetric flask with pure water, and pure water was added up to the marked line to prepare a sample for atomic absorption spectrometry. Separately prepared standard solution (sodium metal
Atomic absorbance was measured using 1ppm, approximately 0.5N hydrochloric acid as a control solution, and the amount of sodium metal was determined from the absorbance ratio. The measurement conditions are as follows. Equipment: Hitachi 180-30 atomic absorption/flame spectrophotometer Wavelength: 589.0 nm Frame: Acetylene-air thermoplastic resin The following resin was prepared. Polycarbonate “Iupilon S-1000” manufactured by Mitsubishi Gas Chemical Co., Ltd. (melting point 250℃) Polyethylene terephthalate “RT 533” manufactured by Nippon Unipet Co., Ltd. (melting point 255℃) Polybutylene terephthalate “Barox 310” manufactured by General Electric Company (melting point 232℃) Implemented Examples 1 to 6/Comparative Examples 1 to 9 Compositions having the mixing ratios shown in Table 1 were melt-molded under the molding conditions shown in Table 2. The performance of the obtained molded product is shown in Table 1. Control example 10 100 parts of the pellets of the saponified ethylene-vinyl acetate copolymer [ ] were again mixed with 300 parts of a 0.3% acetic acid aqueous solution.
The sample was immersed in a portion of the sample, stirred at 30°C for 1 hour, and washed twice. After filtering the slurry, the obtained pellets were mixed with 300 parts of water again to form a slurry,
Washing with water was repeated three times while stirring at 30° C. for 1 hour, and the mixture was filtered and dried. The saponified ethylene-vinyl acetate copolymer thus obtained had a saponification degree of 99.0 mol% and an ash content.
0.8ppm and sodium metal 0.5ppm. The saponified ethylene-vinyl acetate copolymer was blended with polycarbonate in the same manner as in Example 1,
After melt-molding in the same way, the impact strength and transparency (haze value) were measured, and the results were 65Kg.
cm/cm and 2.0%. Control Example 11 The saponified ethylene-vinyl acetate copolymer [] was treated with acid and washed with water again in the same manner as in Control Example 10 to obtain ethylene-vinyl acetate with a degree of saponification of 99.0 mol%, ash content of 2 ppm, and sodium metal 0.3 ppm. A saponified copolymer was obtained. The saponified ethylene-vinyl acetate copolymer was blended with polybutylene terephthalate in the same manner as in Example 3, and after melt-molding in the same manner, the impact strength and transparency (haze value) were measured, and the result was 4.0 Kg. cm/cm and 5.8%. The impact strength and transparency were measured as follows. Impact strength (injection molded products): Based on ASTM D 256 with izotted and notched (for polycarbonate only, the test piece thickness is 1/8") Transparency (extrusion molded products): Based on ASTM D 1003, Murakami color technology research Measurements were carried out on a film with a film thickness of 50 μm using a manufactured haze meter. [Effects] As mentioned above, the composition of the present application allows molded products with excellent physical properties to be obtained, and can be used in packaging materials and engineering plastics. It can be used as

【table】

【table】

【table】

Claims (1)

[Scope of Claims] 1 (1) 100 parts by weight of a thermoplastic resin selected from polycarbonate resins and polyester resins; and (2) ethylene content of 20 to 60 mol% and saponification degree of vinyl acetate portion of 95 mols. % or more, and the ash content is 1 to 20 ppm and the alkali metal content is 0.5
A thermoplastic resin composition with good thermal stability, comprising 0.1 to 1 part by weight of a saponified ethylene-vinyl acetate copolymer of ~5 ppm.