JPH0872118A - Production of permanently antistatic methacrylic resin laminated sheet - Google Patents

Abstract

PURPOSE: To obtain a permanently antistatic methacrylic resin laminated sheet superior in appearance by preventing a permanently antistatic resin composition from discoloring and fading in an extruding machine. CONSTITUTION: In the production method of a permanently antistatic methacrylic resin laminated sheet, when a sheet is produced by laminating a permanently antistatic resin composition of a polyether esteramide and a methacrylic resin on one or both surfaces of a methacrylic resin by coextrusion, inactive gas is introduced into a material hopper of an extruding machine extruding the permanently antistatic resin composition, and the sheet is extruded with the replacement of air in the material hopper by the inactive gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a permanent antistatic methacrylic resin laminated sheet having a good appearance.

[0002]

BACKGROUND OF THE INVENTION Synthetic polymeric materials are used in a wide variety of fields due to their excellent properties. By imparting antistatic properties to these materials, their applications can be further expanded. That is, it is extremely useful for developing applications such as OA equipment nameplates, automobile instrument covers, lighting covers, displays, and projection television screens. In response to such a demand, research on an antistatic plate has been made so far, and recently, a methacrylic resin plate exhibiting a permanent antistatic property has been disclosed in, for example, JP-A-4-71844 and JP-A-5-184844.
It is disclosed in Japanese Patent No. 84875. However, during production of these permanent antistatic resin plates, discoloration and discoloration in the extruder resulted in poor appearance, making continuous and stable production difficult.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to produce a permanent antistatic methacrylic resin laminated sheet having excellent appearance by preventing discoloration and fading of the permanent antistatic resin composition in an extruder. .

[0004]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that when extruding the permanent antistatic resin composition, the air in the extruder is replaced with an inert gas, It was found that discoloration can be prevented by blocking contact with air, and the present invention has been completed.

That is, according to the present invention, a sheet in which a permanent antistatic resin composition comprising a polyether ester amide (A) and a methacrylic resin (B) is laminated on one side or both sides of a methacrylic resin is coextruded. When manufacturing
Introducing an inert gas into an extruder raw material hopper for extruding the permanent antistatic resin composition, and forming a sheet while replacing air in the raw material hopper with the inert gas, a permanent antistatic methacrylic resin laminated sheet It is a manufacturing method.

Hereinafter, the present invention will be described in detail. As the permanent antistatic resin composition used in the laminated portion of the present invention, for example, those disclosed in JP-A-2-283748 are used. As the polyether ester amide (A),
(A) an aminocarboxylic acid having 6 or more carbon atoms, a lactam, or a salt of a diamine having 4 or more carbon atoms and a dicarboxylic acid, (b)
A poly (alkylene oxide) glycol having a number average molecular weight of 400 to 4000 and at least one diol selected from α, ω-dihydroxy hydrocarbons and (c) a dicarboxylic acid having 4 to 16 carbon atoms are used. .

As the component (a) aminocarboxylic acid having 6 or more carbon atoms, lactam, or salt of diamine and dicarboxylic acid having 4 or more carbon atoms, which is a constituent of the polyether ester amide (A) used in the present invention, ω -Aminocaproic acid, ω-aminoenanthic acid, ω-aminocaprylic acid, ω
-Aminobergonic acid, ω-aminocapric acid and 11-
Aminocarboxylic acids such as aminoundecanoic acid and 12-aminododecanoic acid, caprolactam, enanthlactam,
Lactams such as capryl lactam and laurolactam,
Hexamethylenediamine-adipine sun salts, hexamethylenediamine-sebacate salts and salts of diamine-dicarboxylic acids such as hexamethylenediamine-isophthalic acid, especially caprolactam, 12-aminododecanoic acid, hexamethylenediamine-adipic acid salt. Is preferably used.

Further, (a) an aminocarboxylic acid having 6 or more carbon atoms, a lactam, or a salt of a dicarboxylic acid having 4 or more carbon atoms and a dicarboxylic acid is contained in an amount of 10 to 70% by weight as a constituent component of the polyetheresteramide (A). Used in a range. 1
If it is less than 0% by weight, the mechanical properties of the polyether ester amide (A) are inferior, and if it exceeds 70% by weight, the antistatic property of the obtained resin is inferior, which is not preferable.

Specific examples of at least one diol selected from (b) poly (alkylene oxide) glycol and α, ω-dihydroxy hydrocarbon which are other constituents of the polyether ester amide (A) are given below. As the poly (alkylene oxide) glycol,
Polyethylene glycol, poly (1,2-propylene oxide) glycol, poly (1,3-propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol,
Examples include block or random copolymers of ethylene oxide and propylene oxide, and block or random copolymers of ethylene oxide and tetrahydrofuran,
Further, as the α, ω-dihydroxy hydrocarbon, polyolefin glycol obtained by polymerizing olefin or butadiene to form a hydroxyl group at the terminal and hydrogenating the double bond, hydrogenated polybutadiene glycol, or 1,3-propanediol. , 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, and alkylene oxide adducts of bisphenols. Among these, polyethylene glycol is particularly preferably used because of its excellent antistatic property.

The number average molecular weight of (b) poly (alkylene oxide) glycol and α, ω-dihydroxy hydrocarbon is used in the range of 400 to 4000, particularly 600 to 2000. When the number average molecular weight is less than 400, the resulting polyether ester amide (A) has poor mechanical properties, and when the number average molecular weight is more than 4000, charging performance is insufficient, which is not preferable.

The dicarboxylic acid having 4 to 16 carbon atoms (c) which is another constituent of the polyether ester amide (A) includes terephthalic acid, isophthalic acid, phthalic acid and naphthalene-2,6-dicarboxylic acid. , Naphthalene-2,7-dicarboxylic acid, diphenyl-4,6'-dicarboxylic acid, diphenoxyethanedicarboxylic acid and aromatic dicarboxylic acids such as sodium 3-sulfoisophthalate, 1,4-cyclohexanedicarboxylic acid, 1,2. -Cyclohexanedicarboxylic acid and dicyclohexyl-4,
Aliphatic dicarboxylic acids such as 4'-dicarboxylic acid, succinic acid, oxalic acid, adipic acid, sebacic acid, and aliphatic dicarboxylic acids such as dodecanoic acid (decanedicarboxylic acid), and the like, particularly terephthalic acid, isophthalic acid, 1,
4-Cyclohexanedicarboxylic acid, sebacic acid, adipic acid and dodecanedicarboxylic acid are preferably used in terms of polymerizability, color tone and physical properties. (B) Poly (alkylene oxide) glycol or α, ω-dihydroxy hydrocarbon and (c) dicarboxylic acid are reacted at a molar ratio of 1: 1 in terms of reaction, but usually charged depending on the kind of dicarboxylic acid used. Supplied in different ratios.

The method for polymerizing the polyether ester amide (A) is not particularly limited, and for example, (a) (a) an aminocarboxylic acid, a lactam, or a salt of a diamine and a dicarboxylic acid and (c) a dicarboxylic acid are reacted. Then, a polyamide prepolymer having carboxyl groups at both ends is prepared, and (b) poly (alkylene oxide) is added to the polyamide prepolymer.
A method of reacting glycol or α, ω-dihydroxy hydrocarbon under vacuum, (b) charging each of the compounds (a), (b) and (c) into a reaction tank and pressurizing at high temperature in the presence of water A method in which a carboxylic acid-terminated polyamide prepolymer is produced by reaction, and then the polymerization is allowed to proceed under normal pressure or reduced pressure, and (c) the compounds of (a), (b), and (c) above are simultaneously reacted in a reaction vessel. It is possible to use a known method such as a method in which the mixture is charged into the reactor, melt-mixed, and then polymerized at once under high vacuum.

As the methacrylic resin (B) blended with the polyether ester amide (A) as the laminated portion resin of the present invention and the methacrylic resin used for the substrate portion of the present invention, a resin mainly containing methyl methacrylate is used. These include homopolymers of methyl methacrylate, methyl methacrylate and methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, butyl acrylate, acrylonitrile, acrylic acid, methacrylic acid, vinyl pyridine, vinyl morpholine, vinyl pyridone tetrahydro. Furfuryl acrylate, N, N-dimethylaminoethyl acrylate,
A copolymer with any one or more of copolymerizable monomers such as N, N-dimethylacrylamide, 2-hydroxy acrylate, ethylene glycol monoacrylate, glycerin monoacrylate, maleic anhydride, styrene and α-methylstyrene, Impact resistant acrylic resin,
A heat resistant acrylic resin and a low hygroscopic acrylic resin are included. These may be used alone or may be blended.

The impact-resistant acrylic resin has a rubber elastic body as disclosed in JP-A-53-58554 and JP-A-55-949.
No. 17, JP-A No. 61-32346, etc., but briefly described is a multi-step sequential polymerization method in which an elastic layer and an inelastic layer are alternately formed around an acrylic polymer core material. It is a multistage polymer produced. An example of heat-resistant acrylic resin is Japanese Patent Publication No. 61-49325.
However, acrylic acid and methacrylic acid are added to a unit derived from an ethylenically unsaturated monomer consisting of an alkyl methacrylate and an alkyl methacrylate and an aromatic vinyl compound such as styrene in some cases in the molecule. , Unsaturated carboxylic acids such as maleic anhydride, unsaturated dicarboxylic acid anhydrides, those having a 6-membered ring anhydride (glutaric anhydride) unit and / or a 6-membered ring imide unit. The alkyl methacrylate referred to here has 1 to 1 carbon atoms.
4 having an alkyl group of 4.

A low hygroscopic acrylic resin is disclosed in, for example, Japanese Patent Laid-Open No.
Methyl methacrylate, cyclohexyl methacrylate, C _8-20 alicyclic methacrylate, C _3-8 alkyl methacrylate, monoalkenyl aromatic monomer disclosed in JP-A-8-113214 and JP-A-59-227909. It is a copolymer such as an alkyl acrylate and has improved hygroscopicity of an acrylic resin.

The methacrylic resin used in the substrate portion in the present invention may be the same as or different from the methacrylic resin (B) used in the laminated portion. The content of the polyetheresteramide (A) contained in the permanent antistatic resin composition used in the laminated portion of the present invention is preferably 3 to 40% by weight, more preferably 5 to 25% by weight.
Is. If it is less than 3% by weight, the antistatic property is inferior, and if it exceeds 40% by weight, mechanical properties and surface hardness are deteriorated, which is not preferable.

In the present invention, it is effective to add metal salts of sulfonic acid and organic phosphoric acid in order to further exhibit the antistatic effect. Specific examples thereof include alkali metal salts or alkaline earth metal salts of aromatic sulfonic acids such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dodecyldiphenyletherdisulfonic acid, naphthalenesulfonic acid, and a condensation product of naphthalenesulfonic acid and formalin. Or organic carboxylic acids such as stearic acid, lauric acid and polyacrylic acid, and alkali metal salts or alkaline earth metal salts such as diphenyl phosphite and diphenyl phosphate. Of these, sodium salts or potassium salts are particularly preferable. The blending amount of the component is 0. 1 with respect to 100 parts by weight of the total amount of the polyether ester amide (A) and the methacrylic resin (B) component.
1 to 5 parts by weight is preferable. If it is less than 0.1 part by weight, the use effect is not sufficiently exhibited, and if it exceeds 5 parts by weight, the surface of the molded product is roughened or colored during molding, which is not preferable.

Other components such as an inorganic or organic light diffusing agent, a pigment, a dye, a reinforcing agent, a filler, a release agent, etc. may be added to the laminated portion and / or the substrate portion of the present invention as long as the physical properties thereof are not impaired. A heat stabilizer, an antioxidant, a nucleating agent, a light stabilizer, an ultraviolet absorber, a plasticizer, other polymers and the like can be contained in any process such as a kneading process or a molding process. The inert gas introduced into the extruder raw material hopper in the present invention includes nitrogen gas, argon gas, carbon dioxide gas and the like, but nitrogen gas is generally used. When the above-mentioned permanent antistatic resin composition is extruded by an extruder, the parts that may come into contact with air include the raw material hopper and the degassing part (vent part). In particular, the air in the raw material hopper is entrained in the extruder together with the raw material resin, and the resin composition melted in the extruder is burned and discoloration occurs. Therefore,
By filling the inside of the raw material hopper with nitrogen gas and replacing the air in the raw material hopper with nitrogen gas, it is possible to prevent air entrapment and prevent contact with air in the extruder. At this time, the oxygen concentration in the raw material hopper is preferably 1% or less. When the oxygen concentration exceeds 1%, the effect of preventing discoloration and fading is weak, which is not preferable. On the other hand, the degassing section (venting section) is preferably degassed by a vacuum pump or the like in order to avoid contact with air, as in the case of normal extrusion.

In the present invention, it was confirmed that a laminated sheet having an antistatic property can be obtained if the thickness of the laminated portion laminated on the substrate portion is 5 to 500 μm, but it is preferably 10 to 300 μm. The thickness may be the minimum required thickness, but generally it can be used as a laminated sheet having a laminated portion of 30 to 200 μm. Further, when the thickness of the laminated portion is 30% or less in the entire laminated sheet, the physical properties are less likely to deteriorate (when laminated on both sides, the total thickness of the laminated portions on both surfaces is 30% or less of the thickness of the entire laminated sheet).

In coextrusion, two or more ordinary extruders are used and the substrate portion is an extruder of 40 mmφ, 60 mmφ, 90 mmφ, etc., and the laminated portion is smaller than that, 20 mmφ, 30 mm.
A φ, 45 mmφ extruder is used. The permanent antistatic resin composition used in the laminated part is obtained by mixing the above polyether ester amide (A) in the methacrylic resin (B) in advance using a blender or the like to homogenize it and then pelletizing it with an extruder. To use. The laminate of the present invention can be applied to a film as well as a sheet.

In the case of a sheet, the thickness of the laminated portion and the substrate portion of the laminated sheet and laminated film is controlled by the extrusion amount of two or more extruders and the roll clearance of the polishing roll at the extruder outlet, and in the case of a film. It can be adjusted by the extrusion amount of two or more extruders and the roll speed of the take-up roll at the extruder exit. Further, when producing a laminated sheet, it is important to match the fluidity of the so-called laminated portion and the substrate portion, and this can be specifically carried out by adjusting the temperature of the extruder.

The thickness of the laminated part and the whole layer of the laminated sheet can be almost quantified by the extrusion amount of the extruder. When the thickness is 1 mm or more, the thickness is measured with a caliper, and when the thickness is 1 mm or less, the sheet cross section is a differential interference microscope or A commercially available film thickness meter (for example, PIG Universal manufactured by BIC Malincklot (West Germany))
Rsal (thickness meter for dry film))
When it is smaller, it can be seen with an electron microscope. It is convenient to preliminarily mix a small amount of a coloring agent such as a dye with the resin of the laminated portion in order to clarify the interface between the laminated portion and the substrate portion and to facilitate the measurement of the thickness of the laminated portion.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples.

[0024]

[Production Example 1] Preparation of polyetheresteramide (A): 26 parts by weight of caprolactam, 73 parts by weight of polyethylene glycol having a number average molecular weight of 1000 and 9 parts by weight of adipic acid were used as antioxidants (trade name: Irganox 1010, Ciba Geigy). 0.15 parts by weight) and antimony trioxide catalyst 0.1.
15 parts by weight was charged into a reaction vessel equipped with a helical ribbon impeller, and the atmosphere was replaced with nitrogen, and the mixture was heated and stirred at 240 ° C. for 60 minutes to obtain a transparent homogeneous solution.
Polymerization was carried out for 4 hours under the condition of Hg or less to obtain a transparent polymer. Discharge this polymer in a gut shape on the cooling belt,
Pelletized polyetheresteramide (A) was prepared by pelletizing. Preparation of Laminated Part Permanent Antistatic Resin Composition (C): The laminated part permanent antistatic resin composition (C) is a copolymer of methyl methacrylate and methyl acrylate (Del powder (trademark) as the methacrylic resin (B)). ) 70H manufactured by Asahi Kasei Co., Ltd., and mixed with 10 parts by weight of the above polyether ester amide (A), 90 parts by weight of methacrylic resin (B), and 0.5 parts by weight of sodium dodecylbenzenesulfonate to prepare a stabilizer. As a hindered phenolic stabilizer (trade name Sanol LS770, manufactured by Ciba Geigy)
0.3 parts by weight, heat stabilizer (trade name Phosphite 16
(Manufactured by Ciba Geigy Co., Ltd.) (0.2 parts by weight) was blended using a tumbler, then melt-kneaded at a resin temperature of 250 ° C. with a vented extruder 40 mmφ and pelletized to prepare a permanent antistatic resin composition (C).

[0025]

Example 1 An extruder having a diameter of 20 mm and L / D = 32 was used as the raw material for the laminated portion of the above-mentioned permanent antistatic resin composition (C), while a copolymer of methyl methacrylate and methyl acrylate was used for the substrate portion. (Delpet (trade name) 70H
Asahi Chemical Industry Co., Ltd.) diameter 40 mm, L / D = 32
Co-extrusion was carried out using the extruder. An oxygen concentration meter (Model OM-51 manufactured by Komei Rikagaku Co., Ltd.)
It was extruded while being filled with nitrogen so that the oxygen concentration in the hopper measured in 1) was 1% or less. Moreover, the extruder degassing part (vent part) of the resin for lamination part was extruded by degassing with a vacuum pump so that the vacuum degree of the degassing part was 160 mmHg or less. The die is a 2-block 2-layer feed block type, the lip opening is 3.0 mm, and the extruder temperature is 265 ° C.
I went there. The thickness of the laminated sheet was adjusted so that the clearance of the polishing roll was 2.0 mm. In this way, a sheet with a width of 50 cm is prepared and extruded 2
The number of occurrences of discoloration occurring after the lapse of time was visually counted. The results are shown in Table 1.

[0026]

Example 2 The deaeration part (vent part) was not deaerated, a pipe for introducing nitrogen was provided at the deaeration port, and the product was extruded while being filled with nitrogen so that the oxygen concentration in the deaeration part was 1% or less. A laminated sheet was formed in the same manner as in Example 1 except for the above. The results are shown in Table 1.

[0027]

[Comparative Example 1] Except that the nitrogen was not introduced into the hopper, the hopper was opened to be filled with air, and the deaeration part (vent) was opened without deaeration and nitrogen filling. A laminated sheet was formed in the same manner as in Example 1. The results are shown in Table 1.

[0028]

[Comparative Example 2] Nitrogen was not introduced into the hopper, and the hopper was opened to be filled with air, while the degassing section (vent section) was equipped with a nitrogen introducing pipe at the degassing port. A laminated sheet was formed in the same manner as in Example 1 except that the material was extruded while being filled with nitrogen so that the partial oxygen concentration was 1% by volume or less. The results are shown in Table 1.

[0029]

[Table 1]

[0030]

According to the method for producing a permanent antistatic resin laminated sheet of the present invention, a permanent antistatic laminated sheet having a stable appearance for a long time and having a good appearance can be obtained, and can be produced at a low cost. Therefore, for example, including lighting covers, nameplates, displays, meter covers, etc.
It is suitably used as a material capable of preventing static electricity in various parts such as electronic products and office automation equipment, various display boards, and signboards.

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Claims (1)

[Claims] 1. When a sheet in which a permanent antistatic resin composition comprising a polyether ester amide (A) and a methacrylic resin (B) is laminated on one or both sides of a methacrylic resin by coextrusion, Introducing an inert gas into an extruder raw material hopper for extruding the permanent antistatic resin composition, and forming a sheet while replacing air in the raw material hopper with the inert gas, a permanent antistatic methacrylic resin laminated sheet Production method.