JP2626763B2 - Antistatic acrylic resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an antistatic acrylic resin composition comprising an acrylic resin, an anionic surfactant having a specific structure, and trisalkylphenylphosphite.

[Prior art] Acrylic resin has excellent transparency, optical properties, good mechanical properties, processing properties, and appearance.
Widely used for decorative items. However, since acrylic resin has a large electric insulation property, it is easily charged by accumulation of static electricity. This charging phenomenon not only deteriorates the appearance of the acrylic resin but also hinders the work process. For this reason, antistatic methods for acrylic resins have been widely studied.

Incidentally, cationic, anionic and nonionic surfactants are known as general internal addition type antistatic agents for synthetic resins. The antistatic effect of this method is exhibited when these activators bleed out to the surface of the synthetic resin.

However, since the processing temperature of the acrylic resin is relatively high, it is difficult to use a cationic activator having poor thermal stability as an internally added antistatic agent.

Further, since the glass transition temperature of an acrylic resin is higher than that of a polyethylene resin or a polypropylene resin, when a nonionic activator is used, it is necessary to add a large amount to the resin. In that case, the heat-resistant deformation temperature and the transparency are reduced, and the basic characteristics inherent to the acrylic resin are impaired. Also, when a large amount of polyalkylene glycol is added, it excessively bleeds out on the resin surface and the molded product becomes sticky and cannot be put to practical use.

In addition, when a sulfonate-based anionic activator is used, antistatic performance is exhibited, but when used alone, there is a problem in that the appearance of the molded article is impaired due to coloring and deterioration in transparency. .

In order to solve these problems, antistatic acrylic resin compositions using various additives in combination have heretofore been proposed.

For example, Japanese Patent Publication No. 53-30724 discloses a combination system of a sulfonic acid group-containing compound, a phosphoric ester and a polyalkylene glycol. However, it is necessary to use p-toluenesulfonate and a large amount of polyalkylene glycol as the antistatic agent, and it is necessary to add these in an amount of at least 10 parts by weight based on 100 parts by weight of the acrylic resin. Therefore, there is a problem that the heat-resistant deformation temperature and the transparency are lowered. Another problem is that the antistatic agent used bleeds out excessively on the resin surface and the molded product becomes sticky.

Japanese Patent Publication No. 60-3845 proposes an antistatic acrylic resin composition containing a sulfosuccinate or sulfoacetate anionic activator and a fatty acid monoglyceride. However, these additives have little effect on the physical properties of the resin, but have insufficient antistatic performance.

Further, Japanese Patent Publication No. 46-36459 discloses a composition using an anionic activator and other additives, a polyalkylene ether, a sulfonic acid-based anionic activator and a phosphoric acid or phosphite triester. A polyester resin composition using an inhibitor is disclosed. However, when the antistatic agent is kneaded into the acrylic resin, the transparency is reduced, and excessive slippage occurs due to bleed-out of the polyalkylene ether, which causes a problem in molding processing.

As described above, at present, an antistatic acrylic resin having stable antistatic performance without deterioration in appearance and physical properties has not yet been obtained.

[Object of the Invention] An object of the present invention is to provide an antistatic acrylic resin composition having stable antistatic performance without deteriorating resin properties, transparency, color and other appearance.

[Configuration] According to the present invention, 98.5 to 94.0% by weight of an acrylic resin, a compound represented by the following general formula (I) or (II) 1.
0-5.0 tris-alkylphenyl phosphite having a linear or branched alkyl group of% by weight and C ₆ -C ₂₀
An antistatic acrylic resin composition comprising 0.1 to 1.0% by weight is provided.

R ₁ -SO ₃ M (I) (However, R ₁ is a C ₈ -C ₂₂ linear or branched long-chain alkyl group, M is an alkali metal or an alkaline earth metal.) The acrylic resin in the present invention is a methyl methacrylate homopolymer or methacrylic acid. Methyl acrylate and not more than 20% by weight of acrylate or methacrylate,
A copolymer with acrylic acid, methacrylic acid, styrene, acrylonitrile and the like. As acrylic acid esters copolymerizable with methyl methacrylate, for example, methyl acrylate, ethyl acrylate, butyl acrylate, and the like,
Examples of the methacrylate copolymerizable with methyl methacrylate include cyclohexyl methacrylate.

In the present invention, the compound represented by the above general formula (I) or (II) is used as one component of the antistatic agent. However, in this case R ₁ is C ₈ -C _22, preferably a linear or branched long chain alkyl group of C ₁₂ -C _18. M represents an alkali metal such as lithium, sodium and potassium, and an alkaline earth metal such as magnesium and calcium, and sodium is particularly preferably used.

The compound represented by the general formula (I) or the general formula (II) is known as an antistatic agent, but when this compound is applied alone to an acrylic resin, the antistatic performance is exhibited, Since the molded article is colored, the appearance of the molded article is impaired.

The tris-alkylphenyl phosphite having a linear or branched alkyl group of C ₆ -C ₂₀ is the other component of the antistatic agent used in the present invention, tris nonylphenyl phosphite, tris tridecyl phenyl phosphite , Tris isodecyl phenyl phosphite, tris octadecyl phenyl phosphite,
Trisoctylphenyl phosphite and the like can be mentioned.

This trisalkylphenyl phosphite having a C ₆ -C ₂₀ linear or branched alkyl group does not exhibit an antistatic effect when used alone.

In order to exert the effect of the present invention, it is necessary to use the above-mentioned trisalkylphenylphosphite having a C ₆ -C ₂₀ alkyl group in combination with the compound of the general formula (I) or (II). That is, when the compound represented by the general formula (I) or the general formula (II) is used in combination with the above trisalkylphenyl phosphite having an alkyl group of C _{6 to} C _20, a very small amount of addition is required. An effect which cannot be obtained by using the compound alone is exhibited, and an acrylic resin composition having a stable antistatic effect without deteriorating the appearance and physical properties of the resin can be obtained. When other phosphoric acid triesters such as triphenylphosphite and trioctadecylphosphite are used as the phosphoric acid triester, the molded article is colored and the intended effect of the present invention is not achieved.

In the present invention, the compounding ratio of the compound represented by the general formula (I) or the general formula (II) to the trisalkylphenyl phosphite having a C _{6 to} C ₂₀ alkyl group is preferably 10: 1 to 5: 1, more preferably 8: A range of 1-6: 1 is recommended. If the amount of trisalkylphenyl phosphite is smaller than this range, the molded article will be colored. On the other hand, when the amount is larger than this range, trisalkylphenylphosphite does not have an antistatic effect by itself, so that an antistatic effect commensurate with the added amount of trisalkylphenylphosphite is not exhibited.

In the present invention, general formula (I) or general formula (II)
The compound shown in the acrylic resin composition, 1.0 to 5.0
%, Preferably 1.4 to 4.0% by weight. When it is less than this range, the antistatic performance is not exhibited. If it exceeds this range, the transparency of the resin will be reduced. If the heat-resistant deformation temperature of the molded article is within this range, it is almost the same as that of the blank, but if it exceeds this range, the degree of reduction of the heat-resistant deformation temperature increases.

Further, it is necessary to use trisalkylphenylphosphite having an alkyl group of C _{6 to} C ₂₀ in an amount of 0.1 to 1.0% by weight, preferably 0.25 to 0.5% by weight in the acrylic resin composition. . If it is less than this range, the molded article will be colored. Further, when the amount of the trisalkylphenyl phosphite exceeds this range, the use ratio of the additive to the resin increases,
The heat distortion temperature is affected.

The antistatic acrylic resin composition of the present invention can be obtained by a usual acrylic resin molding method.

For example, it can be obtained by melt-kneading an acrylic resin, the compound of the general formula (I) or the general formula (II) and the trisalkylphenyl phosphite with an extruder.

As another method, it can also be obtained by kneading an additive component into an acrylic resin at a high concentration in advance, forming a master pellet, and diluting it at the time of molding.

Further, it can also be obtained by adding a part or all of the compound of the general formula (I) or the general formula (II) and the trisalkylphenyl phosphite at the time of polymerization of the raw material monomer.

Other additives can be added to the acrylic resin composition of the present invention, if necessary, in addition to the essential components. Examples of such additives include antioxidants, nucleating agents such as inorganic and organic fillers and silica, and lubricants such as ethylenebisamide, monoalkylamide, and fatty acid monoglyceride. It is also possible to use a coloring agent. The molded article obtained from the antistatic acrylic resin composition according to the present invention can be used for various members such as covers and parts of lighting fixtures, electric instruments, and electronic instruments, meter covers, films, sheets, panels, and fibers.

[Effects] The acrylic resin composition of the present invention comprises a sulfonate having a long-chain alkyl group represented by the general formula (I) or (II) and a trisalkylphenyl phosphite having a C _{6 to} C ₂₀ alkyl group. Because it was blended at a specific ratio,
The antistatic effect is manifested with a very small amount of addition, and has a stable antistatic performance without deteriorating the resin properties such as heat distortion temperature, transparency, and appearance such as color.

[Examples] Next, the present invention will be described in more detail with reference to Examples.

Examples 1 to 9 Acrylic resin (Mitsubishi Rayon Co., Ltd., Acrypet V)
H), the compound represented by the general formula (I) or the general formula (II), and trisalkylphenylphosphite were premixed in a Henschel mixer at the ratios shown in Table 1.

This mixture was melt-kneaded at 250 ° C using a vented twin-screw extruder, and the obtained strand was cut with a pelletizer, pelletized, and then injection-molded at 260 ° C with an injection molding machine to form a 100 × 100 × 2mm. A plate was obtained.

These plates were conditioned in a constant temperature room at 23 ° C. and 65% RH for 24 hours, and then the surface resistance was measured. (Using a super-insulation meter SM-10E manufactured by Toa Denpa Co., Ltd.) Further, the surface resistance value of the test piece left for 30 days in the same state was measured. Above 10 ¹³ Ω, no antistatic performance was assumed.

The total light transmittance was measured according to JIS K 7013, and the heat distortion temperature (HDT) was measured according to ASTM D 648-56. The color tone was visually determined by comparing with a blank. (○: no yellowing; Δ: slight yellowing; ×: yellowing) These test results are shown in Table 1.

Comparative Examples 1 to 12 Acrylic resin (Mitsubishi Rayon Co., Ltd., Acrypet V
H), a compound represented by the general formula (I) or the general formula (II) or a comparative compound and a phosphoric acid triester are blended in the proportions shown in Table 1 to obtain an acrylic resin composition according to the method of Example. Evaluation was performed in the same manner as in Examples. Table 1 shows the results.

Claims (1)

(57) [Claims] 1. An acrylic resin of 98.5 to 94.0% by weight, a compound of the following general formula (I) or (II): 1.0 to 5.0:
0.1% by weight of trisalkylphenylphosphite having a linear or branched alkyl group of C _{6 to} C ₂₀
1.0% by weight of an antistatic acrylic resin composition, R ₁ -SO ₃ M (I) (Where R ₁ is a C ₈ -C ₂₂ linear or branched long-chain alkyl group, M is an alkali metal or alkaline earth metal)