JP3147385B2 - Antistatic acrylic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an acrylic resin composition having antistatic properties. In particular, the present invention relates to an acrylic resin composition having excellent antistatic performance even in a low-humidity state without impairing the excellent properties inherent in acrylic resins.

[0002]

2. Description of the Related Art Acrylic resins are widely used for lighting equipment, signboards, nameplates, covers, etc. due to their beautiful luster, good mechanical properties, workability, and beautiful appearance of molded products. However, static electricity induced by contact or friction is liable to be imparted, and therefore, dust or the like adheres to the surface of the resin being used, which impairs the beautiful appearance of the corner, and causes a problem such that the instrument panel pointer may be out of order.

[0003] Therefore, many methods for imparting antistatic performance to an acrylic resin have been proposed.
As disclosed in JP-A-2949 and JP-B-53-21023, compositions to which a hydrophilic substance such as a surfactant or a fatty acid ester of a polyhydric alcohol is added are known.

[0004] On the other hand, Japanese Patent Application Laid-Open Nos. 60-250056 and 61-72061 disclose a technique for achieving an antistatic property even in a low humidity state by adding an alkali metal salt or the like to an acrylic resin. Gazette, JP-A-62-164748,
It is disclosed in Japanese Patent Application Laid-Open No. 2-16142.

[0005]

As disclosed in JP-A-53-112949, a composition containing a hydrophilic substance obtains conductivity by the moisture retained in the hydrophilic substance.
Does not work in low humidity conditions.

In the case of adding the above-mentioned alkali metal salt to impart antistatic performance, it is not possible to impart sufficient antistatic performance due to low conductivity, so that a large amount of alkali metal salt is added. As a result, not only is it disadvantageous economically, but also in the case of outdoor use, the acrylic resin is whitened and the transparency is deteriorated.

[0007] Accordingly, the present invention provides an acrylic resin having transparency,
An object of the present invention is to provide an acrylic resin composition that exhibits antistatic performance even in low humidity conditions without impairing heat resistance and weather resistance.

[0008]

Means for Solving the Problems That is, the present invention provides (a)
Polymer mainly composed of methyl methacrylate: 80 to 9
5 parts by weight, (b) the following general formula (I) or (II) R ¹ O (X) _n R ² (I) R ³ COO (X) _n COR ⁴ (II) (wherein R ¹ and R ² Represents hydrogen or a hydrocarbon group, R ³ and R ⁴ each represent a hydrocarbon group, X represents an oxyalkylene group having 2 to 4 carbon atoms,
n is a number average of 1 to 50) Oxyalkylene compound represented by the following formula: 5 to 20 parts by weight, (c) LiCl, LiClO ₄ , LiI, LiSC
N, LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiP
F ₆ , NaI, NaClO ₄ , NaSCN, NaBr, K
At least one inorganic ionic salt selected from I, KClO ₄ , KSCN, CsSCN, AgNO ₃ and Mg (ClO ₄ ) ₂ : 0.001 based on 100 parts by weight of the total of the above components (a) and (b) ~ 3 parts by weight, and (d) above (c)
An object of the present invention is to provide an antistatic acrylic resin composition containing a solvent having solubility for components.

In the present invention, the polymer mainly composed of methyl methacrylate as the component (a) means a homopolymer of methyl methacrylate or a copolymer with another monomer copolymerizable with methyl methacrylate. And so-called acrylic resin having transparency. The proportion of methyl methacrylate in the copolymer is at least 50% by weight, preferably at least 70% by weight.

Examples of unsaturated monomers copolymerizable with methyl methacrylate include, for example, ethyl methacrylate,
Methacrylic acid alkyl esters such as propyl methacrylate and butyl methacrylate; methyl acrylate, ethyl acrylate, propyl acrylate,
Alkyl acrylates such as butyl acrylate and 2-ethylhexyl acrylate; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and itaconic acid; acid anhydrides such as maleic anhydride and itaconic anhydride; 2-hydroxyethyl Hydroxyl group-containing monomers such as acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, monoglycerol acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, tetrahydrofurfuryl methacrylate, and monoglycerol methacrylate; Nitrogen such as acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, diacetone acrylamide, dimethylaminoethyl methacrylate, etc. Containing monomers; Epoxy group-containing monomers such as allylglycidyl ether, glycidyl acrylate, and glycidyl methacrylate; Alkylene oxide groups such as polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, and polyethylene glycol monoallyl ether Monomer;
Aromatic vinyl monomers such as styrene and α-methylstyrene; other monofunctional monomers such as vinyl acetate, vinyl chloride, vinylidene chloride, vinylidene fluoride, and ethylene; allyl acrylate, allyl methacrylate, divinylbenzene, trivinyl Examples include polyfunctional unsaturated monomers such as methylolpropane triacrylate and polyethylene glycol dimethacrylate.

The polymer mainly composed of methyl methacrylate can be produced by applying a known polymerization method to the above-mentioned monomer, for example, bulk polymerization, suspension polymerization, emulsion polymerization and the like.

In the oxyalkylene compound represented by the general formula (I) or (II) of the component (b) used in the present invention, the hydrocarbon group of R ¹ , R ² , R ³ and R ⁴ is carbon Examples thereof include an alkyl group and an aryl group having a number of 20 or less. Preferably, the total number of carbon atoms of R ¹ and R ² and the total number of carbon atoms of R ³ and R ⁴ are each 20 or less. , A methyl group, an ethyl group, a nonylphenyl group and the like. When n is less than 1, the antistatic performance is hardly exhibited, and when n is more than 50, the resin is hardly dissolved in the methyl methacrylate monomer and the obtained resin has poor transparency.

The amount of the oxyalkylene compound used is:
It is 5 to 20% by weight based on the total amount of the polymer mainly composed of the methyl methacrylate of the component (a) and the oxyalkylene compound of the component (b), and when the amount is less than 5% by weight, the antistatic performance is sufficient. When not expressed, and when it exceeds 20% by weight, the heat resistance of the obtained resin composition is reduced. The above oxyalkylene compounds can be used in combination of two or more.

The inorganic ionic salt of the component (C) is a metal salt soluble in the component (a) and / or the component (b), such as Li, N
a, K, Cs, Ag, and Mg salts. Specifically, LiCl, LiClO ₄ , LiI, LiSCN, L
iBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiPF ₆ ,
NaI, NaClO ₄ , NaSCN, NaBr, KI,
KClO ₄ , KSCN, CsSCN, AgNO ₃ , Mg
(ClO ₄ ) ₂ is used.

The amount of the inorganic ionic salt used is 0.001 to 100 parts by weight based on 100 parts by weight of the total amount of the polymer mainly composed of methyl methacrylate as the component (a) and the oxyalkylene group-containing compound as the component (b). 3 parts by weight, preferably 0.05
１．５1.5 parts by weight. When the amount exceeds 3 parts by weight, the acrylic resin composition tends to be whitened, and when the amount is less than 0.001 part by weight, the antistatic property is not sufficiently exhibited. In addition, two or more of the above inorganic ion salts can be used in combination.

In order to further improve the antistatic property, (C)
A solvent (d) having solubility for the inorganic ion salt of the component is added.

Examples of the solvent for the component (d) include amides such as formamide, dimethylacetamide and dimethylformamide, and alcohols such as methanol and ethanol. Among them, formamide is particularly preferred from the viewpoint of antistatic performance, handleability and the like.

However, when used in a large amount, the acrylic resin becomes turbid or the weather resistance is deteriorated. Therefore, the amount used is at most 1/2 of the oxyalkylene compound, preferably 1 /
4 quantities.

The resin composition of the present invention has been described above.
The components (a), (b), (c) and (d) are mixed, and the more uniform, the better.

As a method for obtaining a uniform composition,
(a) methyl methacrylate or an unsaturated monomer mainly composed of methyl methacrylate as the component,
A method of uniformly dissolving each of the components (b), (c) and (d) in a so-called syrup containing those polymers, and performing bulk polymerization, for example, polymerizing and curing in a cell or a mold and shaping into a predetermined shape There is so-called cast polymerization.

The polymerization at this time is carried out in the presence of a known radical polymerization initiator or in the presence of a so-called redox-based initiator comprising a radical polymerization initiator and an accelerator, by irradiating ultraviolet rays or radiation. It can be performed by a known method such as a method.

Further, if the components (b), (c) and (d) are mixed with the powdery component (a), and the components are uniformly mixed by a well-known melt-kneading method, for example, However, other methods can be adopted.

The resin composition of the present invention can be used after being formed into a desired shape by injection molding, extrusion molding, or the like, or laminated on the surface of ordinary acrylic resin or the like by coextrusion.

In the resin composition of the present invention, a coloring agent, a reinforcing agent, a filler, a releasing agent, a stabilizer, an ultraviolet absorber,
It is also possible to add antioxidants, antistatic agents, flame retardants and the like.

[0025]

The acrylic resin composition of the present invention has an antistatic property without impairing the original transparency, heat resistance and weather resistance of the acrylic resin, and particularly has an antistatic property even in a low humidity state. high.

[0026]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. The evaluation method is as follows. -Antistatic property: After leaving the acrylic resin plate in a state of 23 ° C. and 50% humidity for 24 hours, an applied voltage of 10 was applied using a static honest meter (manufactured by Shishido Shokai) in the same atmosphere.
kv, application time 1 minute, table rotation speed 1300 rpm
m, the half-life of the charged voltage is measured.・ Weather resistance: 60 using Sunshine Weatherometer
The appearance of the acrylic resin plate irradiated for 0 hours was visually examined.

Examples 1 to 3 (Reference) 90 parts by weight of methyl methacrylate and 10 parts by weight of ethylene glycol dimethyl ether were uniformly mixed, followed by 0.08 parts by weight of azobisisobutyronitrile and the amount shown in Table 1. Of LiClO ₄ was dissolved.

This solution was poured into a polymerization cell consisting of two glass plates sandwiching a polyvinyl chloride gasket,
Heat polymerization was performed at 70 ° C. for 3 hours and at 120 ° C. for 1 hour to obtain an acrylic resin plate having a thickness of 3 mm.

The antistatic properties and weather resistance of the obtained acrylic resin plate were evaluated. The results are shown in Table 1.

[0030]

Comparative Example 1 (Reference) An acrylic resin plate was obtained in the same manner as in Example 1 except that LiClO ₄ was not added. The antistatic property was 3 minutes or more.

Comparative Example 2 (Reference) An acrylic resin plate was obtained in the same manner as in Example 3 except that ethylene glycol dimethyl ether was not added. The antistatic property was 3 minutes or more.

Comparative Example 3 (Reference) Example 1 except that 5 parts by weight of LiClO ₄ was used.
An acrylic resin plate was obtained by the same operation as described above. Although the antistatic property was 1 second, the acrylic resin plate was whitened in the weather resistance test.

Examples 4 to 7 (Reference) An acrylic resin plate was obtained in the same manner as in Example 3, except that 10 parts by weight of the oxyalkylene compound shown in Table 2 was used instead of ethylene glycol dimethyl ether. Table 2 shows the evaluation results.

[0035]

Examples 8 to 10 90 parts by weight of methyl methacrylate, 8 parts by weight of ethylene glycol dimethyl ether and 2 parts by weight of formamide were uniformly mixed, and then azobisisobutyronitrile 0.1 part by weight was mixed.
08 parts by weight and the amount of LiClO ₄ shown in Table 3 were dissolved, and the same procedure as in Example 1 was carried out to obtain an acrylic resin plate. Table 3 also shows the evaluation results.

[0037]

Examples 11 to 13 An acrylic resin plate was obtained in the same manner as in Example 10, except that 2 parts by weight of the solvents shown in Table 4 were used instead of formamide. Table 4 also shows the evaluation results.

[0039]

Comparative Example 4 (Reference) Same as Example 10 except that 8 parts by weight of ethylene glycol dimethyl ether and 2 parts by weight of formamide were replaced by 4 parts by weight of ethylene glycol dimethyl ether and 6 parts by weight of formamide. An acrylic resin plate was obtained by the above operation. However, the obtained plate was cloudy and poor in transparency.

Examples 14 to 16 An acrylic resin plate was obtained in the same manner as in Example 10, except that the salt shown in Table 5 was used instead of LiClO ₄ as the inorganic ion salt. Table 5 also shows the evaluation results.

[0042]

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-182838 (JP, A) JP-A-62-161870 (JP, A) JP-A-63-168614 (JP, A) JP-A-3-3 103466 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 33/12 C08K 3/24 C08K 5/06 C08L 33/12 C08L 71/02

Claims (1)

(57) [Claims] (A) a polymer mainly composed of methyl methacrylate: 80 to 95 parts by weight; (b) a compound represented by the following general formula (I) or (II): R ¹ O (X) _n R ² (I) R ³ COO (X) _n COR ⁴ (II) (wherein, R ¹ and R ² each represent hydrogen or a hydrocarbon group, R ³ and R ⁴ each represent a hydrocarbon group, and X has 2 to 4 carbon atoms. Represents an oxyalkylene group of
n is a number average of 1 to 50) Oxyalkylene compound represented by the following formula: 5 to 20 parts by weight, (c) LiCl, LiClO ₄ , LiI, LiSCN, L
iBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiPF ₆ ,
NaI, NaClO ₄ , NaSCN, NaBr, KI,
KClO ₄ , KSCN, CsSCN, AgNO ₃ and M
g (ClO ₄ ) ₂ : at least one inorganic ionic salt: 0.001 to 3 parts by weight based on 100 parts by weight of the total of the above components (a) and (b); and (d) the above (c) Solvent having solubility for the component: above (b)
An antistatic acrylic resin composition, comprising: 以下 or less of the components.