JPH07166074A - Transparent antistatic resin composition for melt molding - Google Patents

Abstract

PURPOSE:To provide a resin composition which is antistatic and can retain its original transparency even when processed or molded at high temperatures by compounding a transparent thermoplastic resin with a water-absorbing resin having a urethane bond. CONSTITUTION:100 pts.wt. of a transparent thermoplastic resin is compounded with 0.1-10 pts.wt. of a water-absorbing resin having a urethane bond and a water absorbing capacity of 10-100g per gram of resin of obtain a resin composition. As the transparent thermoplastic resin, acrylic resins are preferable. The water-absorbing resin can be obtained by reacting a polyether polyol with a compound having an isocyanate group. A preferable polyether polyol is polyethylene glycol because of its excellent water absorbing capacity. Usable isocyanat compounds are those having two or more isocyanate groups in the molecule (e.g. tetramethylene disocyanated). The molar ratio of the polyether polyol to the isocyanate compound is so adjusted that a desired water absorbing capacity can be attained, for example, 70/30-50/50.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent thermoplastic resin composition for melt molding which is excellent in heat resistance stability and antistatic property. Methacrylic resins, styrene resins and polycarbonates are known for their excellent transparency and beautiful appearance, and are used for signboards and various ornaments. However, these resins have problems in that they are easily charged with static electricity, have a reduced gloss, are easily soiled by dust and the like, and have a poor appearance. 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. In Japanese Patent Publication No. 4-98,
30 to 10% by weight of alkylaryl sulfonic acid lithium salt in a transparent polymer material, nonionic surfactant 70 to 9
It is described that 0.5 to 10% by weight of an antistatic agent consisting of 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. The composition described in Japanese Patent Publication No. 4-98 uses an agent having a relatively low molecular weight. Therefore, when the composition is melted and molded, it is vaporized and reduced, and the antistatic performance is deteriorated. Therefore, the present invention provides a resin composition excellent in transparency and antistatic property even when the resin composition is subjected to melt molding such as injection molding or extrusion molding. The present invention provides a transparent antistatic resin composition for melt molding which comprises 100 parts by weight of a transparent thermoplastic resin and 0.1 to 10 parts by weight of a water absorbent resin having a urethane bond. It is to provide things. The transparent thermoplastic resin used in the present invention includes, for example, polyethylene, polypropylene, ethylene-
Polyolefin resins such as vinyl acetate copolymers and ethylene-methyl methacrylate copolymers; acrylic resins whose main component is polymethylmethacrylate; styrene resins;
Vinyl chloride resin; polyester resin; polyacetal resin; polyamide resin; polycarbonate; polyimide resin and the like. These synthetic resins may be used alone or as a mixture and have high transparency. Above all,
Acrylic resin, styrene resin,
Polycarbonate or the like is preferable. More preferably, it is an acrylic resin. The acrylic resin contains methyl methacrylate alone or 50% by weight or more of methyl methacrylate and is copolymerizable with methyl methacrylate, for example, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, Methacrylic acid esters such as phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, acrylic acid Acrylic esters such as benzyl, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, etc., unsaturated fatty acids such as methacrylic acid, acrylic acid, styrene, α-methylstyrene, acrylonitrile, methyl ester Acrylonitrile, maleic acid anhydride,
It is a copolymer with phenylmaleimide, cyclohexylmaleimide, etc., but is not limited thereto. Further, it may further contain an elastomer component such as polybutadiene or polybutyl acrylate copolymer, a glutaric anhydride unit, or a glutarimide unit. The water-absorbent resin having a urethane bond 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, etc., and have one ether bond in the molecule.
No more than 00. Among the polyether polyols, polyethylene glycol is more excellent in 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,
There are polycarbonate polyols such as polyhexamethylene carbonate diol; polyester polyols such as polycaprolactone diol. As the compound having an isocyanate group, a compound having two or more isocyanate groups in the molecule can be used. Examples 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, trimethylhexamethylene 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, polyether polyol / compound having isocyanate group = 70/30 to 50
/ 50 molar ratio, preferably 60/40 to 50/50
Thus, 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 it is less than 10 g water / g resin, the antistatic performance is difficult to be exhibited, and if it exceeds 100 g water / g resin, the resin may be deteriorated after being left for a long time. The amount of the water-absorbent resin is the amount of the transparent thermoplastic resin 1
It is 0.1 to 10 parts by weight per 00 parts by weight. Above all, 0.
5 to 5 parts by weight is preferable. If the amount added is less than 0.1 parts by weight, sufficient antistatic properties will not be exhibited, and if it is more than 10 parts by weight, not only the heat resistance will decrease, but also it will become difficult to be compatible with the transparent thermoplastic resin and the composition will become cloudy. I have something to do. The amount of the water-absorbent resin is more preferably depending on its water-absorbing capacity, more preferably, the value of g water / g resin of the water-absorbing capacity and the value of parts by weight of the water-absorbing resin per 100 parts by weight of the transparent thermoplastic resin. The product is 1 to 200. For the resin composition of the present invention, light diffusing agents, matting agents, dyes, pigments, light stabilizers, ultraviolet absorbers, antioxidants, reinforcing agents, fillers, mold release agents, flame retardants, etc. are well known. Additives may be added. If desired, an organic compound type antistatic agent may be used in combination. Known organic compound antistatic agents that can be used in combination include known alkyl sulfonates and higher fatty acid glycerides. However, an inorganic salt such as an inorganic perchlorate salt causes thermal decomposition of the water-absorbent resin, and therefore it should be avoided in combination. As the method for preparing the thermoplastic resin composition of the present invention from the transparent thermoplastic resin and the water absorbent resin having a urethane bond, both are mechanically mixed with a Henschel mixer, a tumbler, etc., and a Banbury mixer or a uniaxial mixer is used. There is a well-known method of melt-kneading with a twin screw extruder. The melt molding referred to in the present invention means molding by heating the thermoplastic resin to a temperature not lower 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 transparent antistatic resin composition for melt molding of the present invention has an antistatic property without losing the transparency inherent to the resin even when it is subjected to high temperature processing molding such as extrusion molding or injection molding. Can be granted. 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, etc. It can be suitably 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: The acrylic resin plate was left at 23 ° C and 50% humidity for 24 hours, and then applied voltage 10 with a static Honest meter (manufactured by Shishido Shokai) in the same atmosphere.
Kv, application time 1 minute, table rotation speed 1300 rpm,
The half-life of the charged voltage was measured under the conditions.・ Coloring degree: SZ- manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS-K7103
Yellowness (YI) was measured using a Σ80 spectral color difference system. 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, and then weighed and increased (g) was calculated as the amount of water absorption. In addition, when the whole amount of the substance passed through the wire net, the measurement was impossible. Examples 1 and 2, Comparative Example 1 Methacrylic resin beads (SUMIPEX-EXA, manufactured by Sumitomo Chemical Co., Ltd.) 100 parts by weight shown in Table 1 and a polyethylene oxide-based water-absorbing resin having a urethane bond (water-absorbing ability). An amount (30 g water / g resin) shown in Table 1 and 1 part by weight of an antioxidant (manufactured by Irganox 1010 Ciba Geigy) were mixed in a Henschel mixer, and then an extruder (uniaxial,
A screw having a diameter of 40 mm and manufactured by Tanabe Plastic Co., Ltd. was kneaded at a resin temperature of 265 ° C. and pelletized. 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 2. Example 3, Comparative Example 2 100 parts by weight of the same methacrylic resin beads as in Example 1, the water-absorbent resin and the amounts and antioxidants shown in Table 1 were mixed 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 2. Comparative Examples 3 and 4 100 parts by weight of the same methacrylic resin beads as in Example 1 were added to tetraethylene glycol lauryl ether or polypropylene oxide / polyethylene oxide = 2.
Example 3 using the block copolymer of 1/1 in the amount shown in Table 1.
A sheet was obtained in the same manner as above, and the evaluation results of the obtained sheet are shown in Table 2. Comparative Example 5 A sheet was obtained in the same manner as in Example 3, 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 2. [Table 1] [Table 2]

Claims (1)

Claim: What is claimed is: 1. A transparent antistatic resin composition for melt molding, which comprises 100 parts by weight of a transparent thermoplastic resin and 0.1 to 10 parts by weight of a water absorbent resin having a urethane bond. 2. The transparent antistatic resin composition for melt molding according to claim 1, wherein the water absorbing resin having a urethane bond has a water absorbing capacity of 10 to 100 g water / g resin.