JPH032456B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a highly transparent resin composition that has good and permanent antistatic properties. [Prior art] Methacrylic resin generally has a high electrical resistance value,
It is easily charged with electricity due to friction, peeling, etc., and therefore attracts dirt and dust, causing various problems in the fields of molded products, sheets, films, fibers, etc., such as damaging the appearance. Recently, highly reliable antistatic materials are required for shipping containers and packaging materials for electronic components. In general, two methods are used to impart antistatic properties to methacrylic resin: 1. Internal kneading of an antistatic agent 2. Surface coating of an antistatic agent. There are other methods, such as surface coating of a silicon-based compound or modification of the surface structure of methacrylic resin, ie, plasma treatment, but both are expensive. In the method of internally kneading antistatic agents, low-molecular surfactants are generally used, but it is difficult to provide permanent antistatic properties with this method, and the antistatic agent present on the surface is If it is removed by washing with water, friction, or other means, the antistatic property will be lost. In addition, there is a method of using antistatic rubber as seen in JP-A-55-36237, but it is necessary to increase the amount of addition, which deteriorates the physical properties of methacrylic resin such as heat resistance, and this method However, the surface resistivity is also only about 10 ¹¹ Ω, which is not satisfactory. The surface application method of antistatic agent has a surface resistivity of 10 ⁹ Ω.
However, since the antistatic agent is present only in the surface layer, the antistatic property is easily lost by washing with water, friction, etc. Moreover, unlike the internal kneading method, a surface coating process is required, resulting in high costs. [Problems to be solved by the invention] As explained above, no special process is required,
An antistatic agent that permanently exhibits good antistatic properties even when added in a small amount and does not deteriorate the inherent physical properties of the methacrylic resin has not been proposed so far. [Means for Solving the Problems] The present inventors have discovered that methacrylic resin has physical properties such as transparency and heat resistance that are inherent to methacrylic resin, and has good permanent antistatic properties that do not deteriorate due to washing. As a result of intensive research with the aim of creating a methacrylic resin that does not drop, we found that by adding a small amount of a copolymer that has a certain type of quaternary ammonium base and a chemically bonded polyalkylene glycol, it was possible to create a methacrylic resin that does not drop. It has been found that good and permanent antistatic properties can be imparted to methacrylic resin without impairing its inherent physical properties. That is, in the present invention, for 100 parts by weight of methyl methacrylate polymer (), (However, R ₁ is hydrogen or a methyl group, R ₂ to _{R 4} are hydrogen or an alkyl group having 1 to 9 carbon atoms that may have a substituent, m is an integer of 1 to 10, and X ^- is a monovalent 20-90 wt. Antistatic property and The present invention relates to a resin composition with excellent transparency. The counter anion (X ^- ) of the above quaternary ammonium base has the general formula R ₈ SO ₃ ^- or R ₈ OSO ₃ ^- (wherein R ₈ is hydrogen or an alkyl group which may contain a phenyl group having 1 to 20 carbon atoms). ) is preferable. The methyl methacrylate polymer () in the present invention is a polymer comprising 50% by weight or more of methyl methacrylate units and 50% by weight or less of other copolymerizable monomer units. Examples of monomers copolymerizable with methyl methacrylate include alkyl methacrylates such as ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate;
Examples include alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, styrene, acrylonitrile, methacrylic acid, alkyl acids, itaconic acid, maleic acid, fumaric acid, vinyltoluene, etc., and preferably methyl acrylate. alkylacrylates and styrene. Further, the polymer () preferably has an intrinsic viscosity of 0.4 to 0.8 dl/g in a toluene solvent at 25°C. The unit having a quaternary ammonium base in the copolymer ( ) in the present invention has the general formula (However, R ₁ is hydrogen or a methyl group, R ₂ to _{R 4} are hydrogen or an alkyl group having 1 to 9 carbon atoms that may have a substituent, m is an integer of 1 to 10, and X ^- is a monovalent or the corresponding equivalent of an inorganic or organic acid), which is a methacrylate or acrylate with an amine that has been quaternized with a quaternizing agent. . Examples of methacrylates or acrylates having an amine include dimethylamino methacrylate, diethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminobutyl methacrylate, dihydroxyethylaminoethyl methacrylate, dipropylaminoethyl methacrylate, dibutylamino Examples include ethyl methacrylate. Examples of quaternizing agents include alkyl sulfates such as dimethyl sulfate, diethyl sulfate, and dipropyl sulfate, sulfonic acid esters such as methyl p-toluenesulfonate and methyl benzenesulfonate, alkyl sulfites such as dimethyl sulfite, and trimethyl phosphate. Alkyl phosphoric acid, alkyl benzyl chloride,
Various halides such as alkyl chloride, alkyl chloride, and alkyl bromide are used, and alkyl sulfuric acid and sulfonic acid ester are particularly preferred from the viewpoint of heat decomposition resistance. m in the general formula is an integer of 1 to 10, with 2 to 6 being particularly preferred. As the copolymerizable monomer component having a polyalkylene glycol component used in the present invention, a polyalkylene glycol macromer with a styryl terminal, a polyalkylene glycol macromer with a vinyl terminal, etc. can be used, but particularly preferred monomer components are is a general formula (However, R ₅ is hydrogen or a methyl group, R ₆ is an optionally branched alkyl group having 4 or less carbon atoms,
R ₇ is hydrogen or an alkyl group having 1 to 20 carbon atoms, n is an integer of 1 to 500), and this is a polyalkylene glycol macromer with terminal methacrylate or acrylate. Examples include polyethylene glycol
(4) Monomethacrylate, polyethylene glycol (23) monomethacrylate, polyethylene glycol (300) monomethacrylate, polyethylene glycol (23) monoacrylate, polypropylene glycol (23) monomethacrylate, polypropylene glycol (23) monoacrylate,
Polyethylene glycol (23) monomethacrylate monomethyl ether, polyethylene glycol (23) monomethacrylate monobutyl ether,
Polypropylene glycol (23) monoacrylate monomethyl ether, polyethylene glycol (23) monomethacrylate monononyl ether,
Polyethylene glycol (23) monomethacrylate monostearyl ether, polypropylene glycol (23) monomethacrylate monomethyl ether, polyethylene glycol (4) monomethacrylate monomethyl ether, polyethylene glycol (9) monomethacrylate monomethyl ether, polyethylene glycol (300) monomethacrylate monomethyl ether , polyethylene glycol (23) monomethacrylate monooleyl ether (the number in the box is the number of polyalkylene glycol units). Examples of the copolymerizable vinyl monomer in the present invention include known monomers such as methacrylic acid alkyl ester, acrylic acid alkyl ester, acrylic acid, methacrylic acid, acrylamide, methacrylamide, vinyl acetate, unsaturated nitrile, Aromatic vinyl, alkyl vinyl ether, alkyl vinyl ketone, 2-hydroxyalkyl (meth)
One or more monomers such as acrylate, vinyl chloride, vinylidene chloride, isobutene, 2-acidophosphoxyethyl (meth)acrylate, etc. can be used. The composition of the copolymer () in the present invention is 20 to 90% by weight of a monomer component having a quaternary ammonium base, 10 to 80% by weight of a monomer component having a copolymerizable polyalkylene glycol component, The copolymerizable vinyl monomer is 0 to 70% by weight, more preferably the monomer component having a quaternary ammonium base is 30 to 80% by weight, and the monomer component is copolymerizable and has a polyalkylene glycol component. The amount of copolymerizable vinyl monomer or vinylidene monomer is 0 to 50% by weight. Copolymer ()
The monomer component having a quaternary ammonium base in
If the amount is less than 20% by weight, good antistatic properties cannot be imparted to the methacrylic resin, and if the amount of the monomer component having a polyalkylene glycol component is less than 10% by weight, the transparency of the resin composition will decrease. If the copolymerizable vinyl monomer that is the third component is a component that has good compatibility with the methacrylic resin, the transparency of the resin composition that can be obtained even if the monomer component containing the polyalkylene glycol component is reduced If the copolymerizable vinyl monomer is a highly polar monomer, the antistatic properties of the resulting resin composition can be maintained even if the monomer component having a quaternary ammonium base is reduced. Can be maintained. There are no particular limitations on the method for producing the copolymer (2), and techniques such as solution polymerization and bulk polymerization in the presence of ordinary radical-generating initiators and chain transfer agents can be used; This is preferred because it can be directly polymerized. In addition, in the case of solution polymerization,
Various addition methods such as bulk addition, divided addition, and dropwise addition of the monomer can be employed. The molecular weight of the copolymer () in the present invention is 1000
It is preferable that it is above. When the molecular weight is less than 1000, good permanent antistatic properties may not be obtained, and the heat resistance of the methacrylic resin tends to decrease due to the plasticizing effect. The amount of copolymer () added to 100 parts by weight of methyl methacrylate polymer () is 0.1 to 40 parts by weight.
It is preferably 0.5 to 40 parts by weight, particularly preferably 0.5 to 40 parts by weight. If the amount of the copolymer () added is less than 0.1 parts by weight, good antistatic properties cannot be imparted, and if it exceeds 40 parts by weight, the original physical properties of the methacrylic resin will be greatly impaired and the cost will increase. Copolymer ()
It is usually sufficient to add the amount of about 6 parts by weight, and this amount gives a surface resistance value of 10 ⁹ Ω to ^{10 12} Ω. In addition, various methods can be applied to mix the polymer () and the copolymer (), such as a method of polymerizing the polymer () in the presence of the copolymer () and a method of polymerizing the polymer () in the presence of the copolymer (). A method of heating and melt-mixing the polymer () is considered. In order to mold the resin composition excellent in antistatic properties and transparency in the present invention, various molding methods such as injection molding, extrusion molding, and press molding can be applied. The reason why molded products made from the resin composition of the present invention exhibits excellent antistatic properties is due to the unique properties of the copolymer containing a quaternary ammonium base used in the present invention. During molding,
This seems to be due to the fact that this copolymer is concentrated or oriented near the surface of the molded article. The molded product thus obtained is free from tackiness and other defects, has no loss of heat resistance, and has permanent antistatic properties. In the present invention, other antistatic agents, lubricants, antioxidants, ultraviolet absorbers, dyes, pigments, and other additives may be additionally added. As the antioxidant, phosphite type antioxidants are preferred. Next, the present invention will be explained with reference to Examples, but the present invention is not limited by the Examples. The electrical properties of all the samples in Examples were measured under the same conditions as in Example 1, with humidity controlled. The charge half-life time was measured using a static neostometer (manufactured by Shishido Shokai) with an applied voltage of 10,000 V and a sample rotation speed.
Measured under the conditions of 1300 rpm, application time 30 seconds, measurement temperature 23℃, and measurement humidity 65%.The sample voltage when voltage is applied is the initial voltage (V), and the time it takes for the sample voltage to become half of the initial voltage after voltage application. charge half-life time (sec)
And so. The surface resistance value was measured using a super insulation resistance meter (manufactured by Takeda Riken, TR-8601) at a measurement temperature of 23℃ and a measurement humidity of 65% after 1 minute at an applied voltage of 500V. . For cleaning, ultrasonic cleaning was performed at 30°C for 30 minutes. Heat resistance is determined after annealing the sample.
HDT (°C) was measured according to ASTM D648.
The strength was determined by a tensile test according to ASTM D638.
The tensile elastic modulus and tensile breaking strength were measured. Transparency was measured by haze value using an integrating sphere haze meter (SEP-H-SS, manufactured by Nippon Seimitsu Kogaku).
The surface condition indicates the presence or absence of silver streaks; ◯ indicates that no silver streaks appear at all, and △ indicates that some silver streaks were observed. As the methacrylic resin, Acrypet VH (methyl methacrylate methyl acrylate copolymer) manufactured by Mitsubishi Rayon was used. Example 1 374 parts by weight of diethylaminoethyl methacrylate, 4 parts by weight of hydroquinone monomethyl ether, and 450 parts by weight of methanol were placed in a 3L glass flask equipped with a stirring blade, and while stirring, a mixture of 252 parts by weight of dimethyl sulfate and 80 parts by weight of methanol was added. of
The mixture was added dropwise to keep the temperature below 30°C, and stirring was continued for 30 minutes after the completion of the addition to obtain a monomer (M-1) solution containing a quaternary ammonium base. To the monomer (M-1) solution having a quaternary ammonium base, 6 parts by weight of azobisisobutyronitrile, 4 parts by weight of n-octyl mercaptan, 480 parts by weight of methanol, and 620 parts by weight of polyethylene glycol (23) monomethacrylate monomethyl ether. was added and polymerized at 60° C. for 4 hours under a nitrogen atmosphere. After the polymerization, the mixture was dried under vacuum to obtain an antistatic property-imparting copolymer (T-1). 6 parts by weight of the obtained antistatic property-imparting copolymer were mixed with 100 parts by weight of methacrylic resin, and pelletized at 230°C using a 40φ extruder. The pellets obtained are injection molded (cylinder temperature
250℃, mold temperature 60℃) 10cm x 10cm x 2mm
After conditioning the plate at 23℃ and 65% humidity for one day, antistatic properties and transparency were evaluated, and the surface resistivity was 2.0×.
The resistance was 10 ¹⁰ Ω, the charge half-life time was 1 second, and the haze value was 1.5%. Further, the obtained plate was washed with water and the antistatic property was immediately evaluated, and the surface resistivity was 1.5×10 ¹⁰ Ω, and the charge half-life time was 1 second or less. In addition, HDT specimens were prepared according to ASTM D648,
HDT was measured after annealing and was 100℃.
When a tensile test was conducted according to ASTM D638,
Tensile elastic modulus 3.1×10 ⁴ (Kg/cm ² ), tensile breaking strength
It was 710 (Kg/cm ² ). Comparative Example 1 Methacrylic resin pellets were injection molded (cylinder temperature 250°C, mold temperature 60°C) into 10 cm x 10
A cm x 2 mm plate was conditioned for one day at 23℃ and 65% humidity, and the antistatic transparency was evaluated and the surface resistivity
5.3×10 ¹⁶ Ω, charge half-life time over 1 minute, haze value 1.5%
It was hot. In addition, HDT specimens were prepared according to ASTM D648,
HDT was measured after annealing and was 100℃.
A tensile test according to ASTM D638 revealed a tensile modulus of elasticity of 3.3×10 ⁴ (Kg/cm ² ) and a tensile strength at break.
It was 730 (Kg/cm ² ). Examples 2 to 5 1 to 35 parts by weight of the antistatic property imparting copolymer (antistatic polymer) T-1 obtained in Example 1 to methacrylic resin
100 parts by weight, pelletized using an extruder under the same conditions as Example 1, and injection molded into pellets.
A plate of cm x 10 cm x 2 mm was made into a plate, and after being conditioned for one day at 23°C and 65% humidity, the antistatic properties and other properties were evaluated.The results are shown below.

[Table] Comparative Example 2 Antistatic property imparting copolymer T-1 obtained in Example 1
Mix 50 parts by weight with 100 parts by weight of methacrylic resin,
After extrusion shaping under the same conditions as in Example 1, injection molding was performed to create a 10 cm x 10 cm x 2 mm flat plate, and after conditioning at 23°C and 65% humidity for one day, antistatic properties and other physical properties were determined. When evaluated, the results shown in the table below were obtained.

[Table] As can be understood from the above table, when the amount added to impart antistatic property is 50 parts by weight per 100 parts by weight of methacrylic resin, the antistatic performance shows a good value, but the haze value increases and the transparency Gender is lost. In addition, the mechanical properties of the resin also deteriorate. Examples 6 to 27 M-2 shown below by the same method as Example 1
A monomer having a quaternary ammonium base of ~M-6 was obtained.

[Table] However, DEMA……diethylaminoethyl methacrylate DMMA……dimethylaminoethyl methacrylate DEA……diethylaminoethyl acrylate DES……diethyl sulfate DMS……dimethyl sulfate Ts-OMe-p-methyl toluenesulfonate MeCl……methyl Chloride Then, by the same method as in Example 1, M-2 to M
Using a monomer having a quaternary ammonium base of -6, antistatic property-imparting copolymers (antistatic polymers) of T-2 to T-23 shown below were obtained.

【table】

[Table] In the above table, the amounts of various monomers used are expressed in weight percent of the antistatic property-imparting copolymer (the same applies below). Antistatic polymer T-23 contains two polyalkylene glycol monomers. In addition, the meanings of the abbreviations in the table are as follows: E23MAM...Polyethylene glycol (23) monomethacrylate monomethyl ether E500MAM...Polyethylene glycol (500)
Monomethacrylate monomethyl ether E9MAM...Polyethylene glycol (9) Monomethacrylate monomethyl ether E23AM...Polyethylene glycol (23) Monoacrylate monomethyl ether P23MAM...Polypropylene glycol (23)
Monomethacrylate monomethyl ether E23MAS...Polyethylene glycol (23) Monomethacrylate monostearyl ether B23MAM...Polybutylene glycol (23) Monomethacrylate monomethyl ether PMMAMA...Terminal methacrylate PMMA (20)
Macromer BMA...n-butyl methacrylate The obtained various antistatic properties imparting copolymers (antistatic polymers) were mixed with 100 parts by weight of methacrylic resin in the proportions (parts by weight) shown in the table below. ,
The pellets were made into pellets using an extruder under the same conditions as in Example 1, made into 10 cm x 10 cm x 2 mm plates by injection molding, and after being conditioned for one day at 23°C and 65% humidity, the antistatic properties and other properties were evaluated.The results are shown below. show.

【table】

[Table] Example 28 Antistatic property imparting copolymer T-1 obtained in Example 1
6% by weight is mixed with 100 parts by weight of methacrylic resin,
Pelletize with an extruder under the same conditions as in Example 1, form a 2 mm sheet with an injection molder, and
After conditioning for one day at ℃ and 65% humidity, antistatic properties and other properties were evaluated, and the surface resistance value was 8.2×10 ¹⁰ Ω, and the charge half-life time
1.5 seconds, and the haze value was 2% or less. Further, the obtained plate was washed with water and the antistatic property was immediately evaluated, and the surface resistance value was 4.3×10 ¹⁰ Ω, and the charge half-life time was 1.5 seconds. Comparative Example 3 To the monomer (M-1) solution having a quaternary ammonium base obtained in Example 1, 6 parts by weight of azobisisobutyronitrile, 4 parts by weight of n-octylmercaptan, and 480 parts by weight of methanol were added, 60℃
Polymerization was carried out under a nitrogen atmosphere for 4 hours. After the polymerization, the mixture was directly vacuum-dried to obtain an antistatic property-imparting copolymer (T-24). 6 parts by weight of the obtained antistatic property-imparting copolymer were mixed with 100 parts by weight of methacrylic resin, and pelletized using an extruder. The obtained pellets were injection molded under the same conditions as in Example 1 to form a plate of 10 cm x 10 cm x 2 mm.
After conditioning for one day at 23℃ and 65% humidity, the antistatic properties were evaluated and the surface resistivity was 8.0×10 ¹⁰ Ω, and the charge half-life time was 1.5.
It was hot in seconds. However, the haze value was 30%, and transparency was impaired. Comparative Examples 4 to 6 In Comparative Examples 4 to 6, the antistatic property imparting copolymer T-24 obtained in Comparative Example 3 and M-1, a monomer having a quaternary ammonium base, were used.
Antistatic property imparting copolymers T-25 and T- obtained by the same method as in Example 1 and having the compositions shown in the table below.
26 was used.

[Table] The ratio of the antistatic property imparting copolymer shown in the above table to 100 parts by weight of methacrylic resin as shown in the table below (parts by weight)
The pellets were mixed using an extruder under the same conditions as in Example 1, and then molded into pellets of 10 cm x 10 cm by injection molding.
After making it into a 2mm board and conditioning it for 1 day at 23℃ and 65% humidity,
The results of evaluating antistatic properties and transparency are shown below.
In the antistatic polymers of Comparative Examples 4 and 6, no antistatic performance was observed even when the amount of the antistatic property-imparting copolymer added was increased. Further, when the amount of copolymerized polyalkylene glycol is small as in Comparative Example 5, antistatic properties are good, but transparency is impaired.

〔Effect of the invention〕

The resin composition of the present invention has good and permanent antistatic properties, and also maintains excellent physical properties such as transparency, strength, and heat resistance inherent to methacrylic resin. Therefore, it is free from various charging problems that occur in the fields of molded products, sheets, films, textiles, etc., such as attracting dirt and dust and damaging the appearance, and can also be used in industrial fields that require high reliability such as electronics. can do.

Claims (1)

[Claims] 1. For 100 parts by weight of the methyl methacrylate polymer (), the general formula (However, R ₁ is hydrogen or a methyl group, R ₂ to _{R 4} are hydrogen or an alkyl group having 1 to 9 carbon atoms that may have a substituent, m is an integer of 1 to 10, and X is a monovalent 20 to 90% by weight of a monomer component having a quaternary ammonium group (representing an inorganic or organic acid group or a corresponding equivalent of an inorganic or organic acid), a copolymerizable polyalkylene glycol component Antistatic properties and transparency obtained by mixing 0.1 to 40 parts by weight of a copolymer () consisting of 10 to 80% by weight of a monomer component having the following properties and 0 to 70% by weight of a copolymerizable vinyl monomer component Excellent resin composition. 2. A resin composition with excellent antistatic properties and transparency according to claim 1, characterized in that the polymer () and the copolymer () are mixed in a heated molten state. 3 A monomer component that is copolymerizable and has a polyalkylene glycol component has the general formula (However, R ₅ is hydrogen or a methyl group, R ₆ is an optionally branched alkyl group having 4 or less carbon atoms,
Antistatic properties and transparency according to claim 1, characterized in that R ₇ is a monomer represented by hydrogen or an alkyl group having 1 to 20 carbon atoms, and n is an integer of 1 to 500. A resin composition with excellent properties. 4 Counter anion of quaternary ammonium base
X ^- is represented by the general formula R ₈ SO ₃ ^- or R ₈ OSO ₃ ^- (wherein R ₈ is hydrogen or an alkyl group which may contain a phenyl group having 1 to 20 carbon atoms) Claim 1
A resin composition with excellent antistatic properties and transparency as described in 1.