JPH0812843A - Antistatic methacrylic resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition containing a methacrylic resin, a water-absorbing resin having an urethane bond and a sodium sulfonate group- containing compound in a specific ratio and excellent in heat stability and antistatic property and useful for melt molding. CONSTITUTION:This composition is composed of (A) 100 pts.wt. of a methacrylic resin and 0.2-10 pts.wt. of total amount of (B) a water-absorbing resin having an urethane bond (preferably having an absorbing capacity of 10-100g water/g resin and (C) a compound having sodium sulfonate group (preferably at least one kind of a sodium alkylsulfonate, a sodium alkylarylsulfonate, sodium succinate sulfonate and sodium acetate sulfonate), and the weight ratio of these components B/C is (10/90) to (90/10).

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, nameplates, etc. 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, so dust etc. will adhere to the resin surface during use and it will easily get dirty and have a beautiful 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. Japanese Examined Patent Publication (Kokoku) No. 4-98 discloses that a transparent polymer material contains 30 to 10% by weight of lithium alkylarylsulfonate and 0.5 to 10% by weight of an antistatic agent composed of 70 to 90% by weight of a nonionic surfactant. %, And melt-kneading 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 water-absorbent resin having a urethane bond: a component (A) and a compound having a sodium sulfonate group: a component (B). Of 0.2 to 10 parts by weight, and the weight ratio of component (A) / component (B) is 10/9.
The antistatic methacrylic resin composition is 0 to 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. Acrylic acid esters include methyl acrylate, ethyl acrylate, butyl acrylate, and the like, and methacrylic acid esters include
Examples thereof include ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate and the like. 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. Examples of the polyol include polycarbonate polyols such as polytetramethylene carbonate diol and 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-
Or 1.4-bis (isocyanatomethyl) cyclohexane, trimethylhexane methylene diisocyanate,
Also applicable are sulfonyldiisocyanates and the like, and isocyanurate compounds obtained from the above isocyanate compounds. 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 compound having a sodium sulfonate group in the present invention include sodium alkyl sulfonates such as sodium octyl sulfonate, sodium dodecyl sulfonate and sodium hexadecyl sulfonate; sodium octyl benzene sulfonate and dodecyl benzene. Sodium alkyl aryl sulfonates such as sodium sulfonate, sodium hexadecyl benzene sulfonate, sodium heptadecyl benzene sulfonate, sodium triisopropyl naphthalene sulfonate, sodium dibutyl naphthalene sulfonate: succinate represented by the following chemical formula [Formula 1] Sodium sulfonate; (In the formula, X represents 0 to 15 and R represents an alkyl group or an alkylaryl group.) Sodium acetate sulfonate represented by the following chemical formula [Chemical Formula 2]; [Chemical Formula 2] RO (C ₂ H ₄ O) _X COCH ₂ SO ₃ Na (in the formula, X and R are the same as above) and the like. Among these compounds, sodium alkylsulfonate has an alkyl group having 8 to 2 carbon atoms.
2, sodium alkylaryl sulfonate having an alkyl group of 0 to 22 carbon atoms, and sodium succinate sulfonate and sodium acetate sulfonate having an alkyl group of 4 to 15 carbon atoms,
0 to 1 carbon atoms of the alkyl group in the alkylaryl group
5 is preferable from the viewpoint of compatibility with the methacrylic resin, resulting in a resin composition having good transparency. The total amount of the water-absorbent resin and the compound having a sodium sulfonate group is 0.2 to 10 parts by weight, preferably 100 parts by weight of the methacrylic resin, and more preferably 0.2 to 10 parts by weight.
0.5 to 5 parts by weight. If the total amount of these is less than 0.2 parts by weight, sufficient antistatic performance will not be exhibited, and 10
If the amount is more than the amount by weight, not only the heat resistance is lowered, but also the methacrylic resin becomes difficult to be compatible with each other, and the resulting resin composition may become cloudy. The ratio of the amount of the water absorbent resin to the amount of the compound having a sodium sulfonate group is 10/90 to 9 by weight.
It is 0/10, preferably 20/80 to 80/20. The methacrylic resin composition of the present invention includes well-known antioxidants such as hindered phenol 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 may be added, and further reinforcing fibers such as glass fibers and inorganic fillers may be added depending on the purpose. A well-known method can be used for incorporating the water-absorbent resin and the compound having a sodium sulfonate group into the methacrylic resin used in the present invention to prepare 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 kneading device such as a commonly used uniaxial or biaxial extruder, various kneaders, injection molding or There is a method of directly kneading during a melt processing operation such as extrusion molding. The melt molding referred to in the present invention means molding by heating the thermoplastic resin to a temperature equal to or higher than the melting point of the resin or to 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 for melt molding, that is, even if it is subjected to high temperature processing such as extrusion molding or injection molding, and it is antistatic. It is possible to impart sex. The resin composition is a resin plate for display of display products, glazing for showcases, meter panels for automobiles, Fresnel lenses, lenticular lenses, optical disks, lighting covers, signboards, various types of molded products such as front plates of transmissive displays, Further, 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, leave the acrylic resin plate at 23 ° C and 50% humidity for 24 hours, and then 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. in accordance with 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 3 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 30 g
Water / g resin) and sodium polyoxyethylene nonylphenyl ether succinate sulfonate (addition of 10 mol of ethylene oxide; hereinafter referred to as PSS-Na) and the amount shown in Table 1 and the hindered phenolic antioxidant (BP-101 Sumitomo) 1 part by weight of Chemical Industry Co., Ltd.) 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 degrees to form pellets. The obtained pellets were molded with an injection molding machine (M-140SJ manufactured by Meiki Seisakusho Co., Ltd.) 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 4 100 parts by weight of the same methacrylic resin beads as in Example 1 were mixed with a water absorbent resin, PSS-Na 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. Example 5 The same as Example 1 except that sodium polyoxyethylene nonylphenyl ether acetate sulfonate (addition of 6 mol of ethylene oxide) was used in place of PSS-Na in Example 1 in an amount shown in Table 1. I went to and got a sheet. The evaluation results of the obtained sheet are shown in Table 1. Example 6 A sheet was obtained in the same manner as in Example 1 except that the amount of sodium dodecylbenzene sulfonate shown in Table 1 was used instead of PSS-Na in Example 1. The evaluation results of the obtained sheet are shown in Table 1. Example 7 A sheet was obtained in the same manner as in Example 1 except that the amount of sodium hexadecylbenzenesulfonate shown in Table 1 was used instead of PSS-Na in Example 1. 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 added to polypropylene oxide / polyethylene oxide = 3/7 molar ratio block copolymer having a molecular weight of 400 and PSS-.
A sheet was obtained in the same manner as in Example 7 using Na in the amounts 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: Compound having sodium sulfonate group 2. Component (A): Water absorbent resin having urethane bond is 10 to 100 g water / g resin. A methacrylic resin composition according to claim 1, which has a water absorbing ability. 3. Component (B): The compound having a sodium sulfonate group is at least one selected from sodium alkyl sulfonate, sodium alkylaryl sulfonate, sodium succinate sulfonate and sodium acetate sulfonate. The methacrylic resin composition according to claim 1, characterized in that