JPH07207099A - Antistatic methacrylic resin composition - Google Patents

Abstract

PURPOSE:To provide a resin compsn. which, even when melt-molded, such as injection-molded or extruded, can maintain its antistatic property without sacrificing color and transparency. CONSTITUTION:The resin compsn. comprises 100 pts.wt. methacrylic resin and 0.2 to 10 pts.wt. in total of the following components (A) and (B) in a weight ratio of (10:90) to (90:10). (A): water-absorptive resin having a urethane bond. (B). Lithium alkylarylsulfonate.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a methacrylic resin composition excellent in heat resistance stability and antistatic property. Particularly, it relates to an antistatic methacrylic resin composition for melt molding. [0002] Methacrylic resins are widely used for lighting equipment, signboards, various ornaments and nameplates due to their excellent transparency, good mechanical properties, processability and the beauty of molded products. However, since its surface electric resistivity is large, static electricity induced by contact or friction is unlikely to dissipate and disappear, and therefore dust etc. will easily adhere to the resin surface during use and it will be easy to get a dirty appearance. It has resulted in a loss. To solve this problem, many techniques have been proposed in which an alkyl sulfonate, a higher fatty acid monoglyceride, or a polyether ester amide is mixed in a methacrylic resin. For example, JP-A-3-122165 discloses a conductive resin containing 0.01% by weight or more and 20% by weight of an alkali metal salt and 0.5% by weight or more and 60% or less by weight of a polyether polymer in a transparent resin. Compositions are disclosed. Tokkyo 4-
In JP-A-98, an antistatic agent comprising 30 to 10% by weight of lithium alkylarylsulfonate and 70 to 90% by weight of a nonionic surfactant is added to a transparent polymer material in an amount of 0.5 to 1%.
It is described that 0% by weight is added and melt-kneaded to obtain a transparent polymer material. When the composition described in Japanese Patent Laid-Open No. 3-122165 is melt-molded, the polyether polymer contained therein is decomposed to cause coloration or antistatic property. Performance is often degraded. Since the composition described in JP-B-4-98 uses an antistatic agent having a relatively low molecular weight, when the composition is melted and molded, defects such as streaks and fish eyes occur on the surface of the molded product. And the development of antistatic performance becomes unstable. Therefore, the present invention provides a resin composition which imparts good antistatic properties without impairing transparency even when the methacrylic resin is subjected to melt molding such as injection molding or extrusion molding. That is, according to the present invention, 100 parts by weight of a methacrylic resin and a total of a water-absorbent resin having a urethane bond: a component (A) and a lithium alkylaryl sulfonate: (B) component. And 0.2 to 10 parts by weight, and the weight ratio of component (A) / component (B) is 10/90.
It is an antistatic methacrylic resin composition of about 90/10. The methacrylic resin used in the present invention is not only a homopolymer of methyl methacrylate but also a copolymer of up to 50% by weight of the total vinyl monomer copolymerizable therewith. The vinyl-based monomer copolymerized with methyl methacrylate can be, for example, acrylic acid ester, methacrylic acid ester, acrylic acid, methacrylic acid, styrene, acrylonitrile, or the like. Examples of the acrylate ester include methyl acrylate, ethyl acrylate and butyl acrylate, and examples of the methacrylate ester include ethyl methacrylate, butyl methacrylate and cyclohexyl methacrylate. Further, it may contain a diene rubber component, glutaric anhydride, or a glutaimide unit. The water-absorbent resin having a urethane bond as the component (A) in the present invention is obtained by reacting a polyether polyol with a compound having an isocyanate group. Polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like, and have 100 or less ether bonds in the molecule. Among the polyether polyols, polyethylene glycol is superior to the water absorption capacity. In addition to the polyether polyol, other polyols are combined in an amount of less than 30% of the total polyol,
Alternatively, they can be co-condensed before use. As this polyol, polytetramethylene carbonate diol,
Polycarbonate polyols such as polyhexamethylene carbonate diol; and polyether diols such as polycaprolactone diol. As the compound having an isocyanate group, compounds having two or more isocyanate groups in the molecule can be used. Examples thereof include tetramethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, tolylene diisocyanate, 4 , 4-diphenylmethane diisocyanate, xylylene diisocyanate, lysine diisocyanate,
4,4-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4 (2,6) -diisocyanate, isophorone diisocyanate, 1.3-
Alternatively, 1.4-bis (isocyanatomethyl) cyclohexane, trimethylhexane methylene diisocyanate, sulfonyl diisocyanate, and the like, and isocyanurate compounds obtained from the above-mentioned isocyanate compounds are also applicable. The molar ratio of the polyether polyol and the compound having an isocyanate group may be adjusted according to the target water absorption capacity. Specifically, the molar ratio of the polyether ether polyol / compound having an isocyanate group is 70.
/ 30 to 30/70, preferably 60/40 to 40/6
At 0, the higher the proportion of polyether polyol, the higher the water absorption capacity. The water absorption capacity of the water absorbent resin is 10 to 100 g water /
g resin. If the amount is less than 10 g water / g resin, the antistatic performance is difficult to be exhibited, and if the amount exceeds 100 g water / g resin, the resin may change after standing for a long time. Examples of the lithium alkylaryl sulfonate in the present invention include lithium octylbenzene sulfonate, lithium dodecylbenzene sulfonate, lithium hexadecylbenzene sulfonate, lithium heptadecylbenzene sulfonate, lithium triisopropylnaphthalene sulfonate. , Lithium dibutylnaphthalene sulfonate, and the like. Among these lithium alkylaryl sulfonates, lithium dodecylbenzene sulfonate is particularly preferable in terms of compatibility with the methacrylic resin, resulting in a resin composition having good transparency. The total amount of the water-absorbent resin and the lithium alkylaryl sulfonate is 0.2 to 10 parts by weight, preferably 0.1% by weight, based on 100 parts by weight of the methacrylic resin.
5 to 5 parts by weight. When the total amount of these is less than 0.2 parts by weight, sufficient antistatic performance is not exhibited, and when it is more than 10 parts by weight, not only the heat resistance is deteriorated, but also it becomes difficult to be compatible with the methacrylic resin, The resulting resin composition may become cloudy. The weight ratio of the water absorbent resin to the lithium alkylaryl sulfonate is 10/90.
To 90/10, preferably 20/80 to 80/20. The methacrylic resin composition of the present invention includes well-known antioxidants such as hindered phenolic antioxidants, phosphorus antioxidants and sulfur antioxidants, ultraviolet absorbers and hindered amine light stabilizers. Weathering agents such as stabilizers, flame retardants, colorants, pigments and the like can be added, and further, reinforcing fibers such as glass fibers and inorganic fillers can be added depending on the purpose. A known method can be used for incorporating the water-absorbent resin and the lithium alkylaryl sulfonate into the methacrylic resin used in the present invention to form a composition. For example, there is a method of kneading each component in a molten state, and the melt kneading is not limited to a method of using a generally used kneading device such as a single-screw or twin-screw extruder and various kneaders. There is a method of directly kneading during a melt processing operation such as injection molding and extrusion molding. The melt molding referred to in the present invention means molding by heating the thermoplastic resin at a temperature not lower than the melting point of the resin or at a glass transition temperature + (100 ° C to 250 ° C). For example, injection molding, extrusion molding, press molding and the like. INDUSTRIAL APPLICABILITY The antistatic resin composition of the present invention does not lose the original transparency of the resin and is antistatic, even when it is used for melt molding, that is, when it is subjected to high temperature processing molding such as extrusion molding and injection molding. It is possible to impart sex. The resin composition is used for various molded products such as resin plates for display of display products, glazing for showcases, meter panels for automobiles, Fresnel lenses, lenticular lenses, optical disks, lighting covers, signboards, front plates of transmissive displays, and the like. It is preferably used for various films. The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The evaluation method is as follows. -Total light transmittance (Tt) and haze: Measured by a Poic integrating sphere type haze meter (SEP-HS-30D manufactured by Nippon Seimitsu Optical Co., Ltd.) according to ASTM D 1003-61.・ Antistatic property: In conformity with JIS-K6911, after leaving the acrylic resin plate at 23 ° C. and 50% humidity for 24 hours, in the same atmosphere, ultra-ultra-insulator (SM-10E type manufactured by Toa Denpa Kogyo)
Was used to measure the surface resistivity.・ Coloring degree: SZ- manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS-K7103
Yellowness (YI) was measured using a Σ80 spectroscopic color difference meter. Water absorption capacity: 1 g of the water-absorbent resin was placed in a beaker filled with pure water, stirred for 1 hour, filtered through a 200-mesh wire net, the resin was weighed, and the increased weight (g) was calculated as the water absorption amount. . Examples 1 to 6 and Comparative Examples 1 to 4 100 parts by weight of methacrylic resin beads (SUMIPEX-EXA, manufactured by Sumitomo Chemical Co., Ltd.) and a polyethylene oxide-based water absorbent resin having a urethane bond (water absorption capacity of 30 g
Water / g resin) and lithium dodecylbenzene sulfonate (hereinafter referred to as DBS-Li) in the amounts shown in Table 1 and hindered phenolic antioxidants (BP-101 manufactured by Sumitomo Chemical Co., Ltd.)
1 part by weight was mixed with a Henschel mixer, and then kneaded with an extruder (uniaxial, screw diameter 40 mm, manufactured by Tanabe Plastic Co., Ltd.) at a resin temperature of 265 ° C. to form pellets. Injection molding machine (Meiki Seisakusho Co., Ltd.)
M-140SJ) at a molding temperature of 260 ° C. and a mold temperature of 55 ° C. to obtain a flat plate molded product having a thickness of 3 mm. The evaluation results of the obtained sheet are shown in Table 1. Example 7 100 parts by weight of the same methacrylic resin beads as in Example 1 were mixed with a water absorbent resin, DBS-Li in the amounts shown in Table 1 and an antioxidant in a Henschel mixer, and then in Example 1. The molten resin was extruded using the extruder used, and a sheet having a thickness of 2 mm and a width of 20 cm was obtained through a T-die and three polishing rolls. The evaluation results of the obtained sheet are shown in Table 1. Comparative Example 5 A sheet was obtained in the same manner as in Example 7, except that the same methacrylic resin beads, water absorbent resin, and lithium perchlorate as in Example 1 were used in the amounts shown in Table 1. The evaluation results of the obtained sheet are shown in Table 1. Comparative Example 6 100 parts by weight of the same methacrylic resin beads as in Example 1 were mixed with polypropylene oxide / polyethylene oxide = 3/7 molar ratio block copolymer having a molecular weight of 400 and DBS-.
A sheet was obtained in the same manner as in Example 7 using Li in the amount shown in Table 1, and the evaluation results of the obtained sheet are shown in Table 1. [Table 1]

Claims (1)

Claims: 1. A methacrylic resin comprising 100 parts by weight and a total of 0.2 to 10 parts by weight of the following components (A) and (B), and (A) component / The weight ratio of component (B) is 1
An antistatic methacrylic resin composition having a ratio of 0/90 to 90/10. Component (A): Water-absorbent resin having urethane bond (B) Component: lithium alkylaryl sulfonate (A) Component (A): Water-absorbent resin having urethane bond is 10 to 100 g water / g resin The methacrylic resin composition according to claim 1, wherein the methacrylic resin composition comprises: 3. The methacrylic resin composition according to claim 1, wherein the component (B): the alkylaryl sulfonate is lithium dodecylbenzene sulfonate.