JPH09208790A - Methacrylate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a methacrylate resin composition excellent in releasability in a forming processing and having excellent transparency and weather resistance by compounding a methyl methacrylate polymer with a specific pentaerythritol and a specific polyglycerin fatty acid ester. SOLUTION: This methacrylate resin composition is obtained by compounding (A) a methyl methacrylate polymer with (B) a pentaerythritol (e.g. monopentaerythritol) expressed by formula I or II X<1> to X<11> are each H, (CH2 CH2 O)f H [(f)=1-5], etc.; (n)=0-3} and (C) a polyglycerin fatty acid ester synthesized from (i) a fatty acid or a glycerin fatty acid ester and (ii) glycidol, at a weight ratio of the components B/C of 10/90 to 90/10 and in an amount of 0.02-0.5 pts.wt. of the total of the components B and C based on 100 pts.wt. of the component A. The component C is preferably produced by carrying out an addition-polymerization reaction using the components (i) and (ii) at a molar ratio of the components (ii)/(i)=1-10 in the presence of a phosphoric acid-based acid catalyst at 140-160 deg.C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a methacrylic resin composition having excellent processability. In particular, the present invention relates to a methacrylic resin composition having excellent mold releasability at the time of molding using a mold.

[0002]

BACKGROUND OF THE INVENTION Methacrylic resins are used for automobile parts such as meter covers, optical parts such as optical discs and lenses, and lighting parts such as electric lamp covers by utilizing their excellent transparency, weather resistance and good mechanical properties. It is used. These molded products are generally obtained by injection molding, injection compression molding, etc., but in precision mold molding such as optical lenses and optical disks, the adhesion between the molded product and the mold surface becomes extremely high. Mold release failure occurs in the mold, resulting in a decrease in productivity. Therefore, it has been proposed to add various release agents to the methacrylic resin.

For example, JP-A-61-73754 discloses a methacrylic resin, a polyhydric alcohol, a higher fatty acid ester,
Resin compositions to which higher alcohols, higher fatty acids, higher fatty acid amides, and higher fatty acid metal salts have been added have been proposed.

[0004]

However, in these formulas, X ¹ , X ² , X ³ and X ⁴ are hydrogen or one of those represented by the partial structural units (III) and (IV). .

When injection molding is performed with a resin composition, some mold release performance is recognized, but it is still not sufficient. In addition, the release agent and other additives that are added migrate to the surface of the resin and stain the surface of the mold or the surface of the molded product, or cause coloring of the molded product, thereby significantly reducing the commercial value of the molded product. The present invention provides a methacrylic resin composition that overcomes the drawbacks of conventional mold release agents and exhibits an excellent mold release effect with a smaller blending amount.

[0006]

The present invention provides at least one kind selected from pentaerythritols represented by the above formula (I) or (II) with respect to 100 parts by weight of a methyl methacrylate polymer. And polyglycene fatty acid ester synthesized from fatty acid or glycerin fatty acid ester and glycidol at a weight ratio of 10/90 to 90/10 and 0.02 to
The present invention relates to a methacrylic resin composition containing 0.5 part by weight.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The methyl methacrylate-based polymer in the present invention means a methyl methacrylate homopolymer, or methyl methacrylate and 20% by weight or less of acrylic acid ester or methacrylic acid ester, acrylic acid, methacrylic acid, It refers to a copolymer with styrene, acrylonitrile or a diene rubber, glutaric anhydride, glutarimide and the like. The acrylic acid ester is methyl acrylate, ethyl acrylate, butyl acrylate, etc., and the methacrylic acid ester is ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, etc.

Examples of the pentaerythritol represented by the above formula (I) or (II) in the present invention include monopentaerythritol, dipentaerythritol, tripentaerythritol, tetrapentaerythritol, and pentapentaerythritol. Each ester compound of these pentaerythritol and a carboxylic acid having a hydrocarbon group R having 10 to 22 carbon atoms such as lauric acid, myristic acid, stearic acid, behenic acid, oleic acid, linoleic acid and linolenic acid, and further , And 1 to 5 adducts of ethylene oxide and / or propylene oxide of these pentaerythritols.

If the carbon group of the hydrocarbon group R of each ester compound of the pentaerythritol with a carboxylic acid is less than 10, it has a high volatility and volatilizes during molding, and a sufficient releasing effect cannot be obtained. On the other hand, those having more than 20 carbon atoms have a low compatibility with the methyl methacrylate-based polymer, and are apt to be bleeded on the resin surface, which causes stains of molds and molded articles, which is not preferable. Also, a partial structural unit (III)
And (IV), in which f and g exceed 5, and
In the formula (II), when n exceeds 3, the compatibility with the methyl methacrylate-based polymer is small, so that it easily bleeds onto the resin surface and causes stains of the mold and the molded product, which is not preferable. .

The polyglycene fatty acid ester to be mixed with the methacrylic polymer of the present invention is synthesized from fatty acid or glycerin fatty acid ester and glycidol. The polyglycene fatty acid ester is a polyglycene fatty acid ester having a high content of monofatty acid ester. It is a mixture.

Conventionally, as a method for producing polyglycerin fatty acid ester, (1) esterification reaction of polyglycerin and fatty acids [JAOCS (Journal of American Oil
Chemists' Society) Vol. 58, p. 878 (1981), JP-A-6-41007, etc.], (2) transesterification reaction between polyglycerin and fatty acid esters, (3) polyglycerin and fats and oils Transesterification reaction with compounds, (4) Addition polymerization reaction of glycidol with fatty acid monoglycerides [US
Patent 4,515,775], and (5) addition polymerization reaction of glycidol and fatty acids (see JP-A-51-65705).

The "polyglycerin fatty acid ester synthesized from fatty acid or glycerin fatty acid ester and glycidol and having a high monoesterification rate" in the present invention is produced by the method (5).

Examples of the starting fatty acid used include fatty acids having 7 to 22 carbon atoms. The fatty acid may be a saturated fatty acid or an unsaturated fatty acid, may be a linear fatty acid or a fatty acid having a side chain, and may be a substituted fatty acid having a carbon chain substituted with a hydroxyl group. Specific examples of these fatty acids include caproic acid, caprylic acid, 2-ethylhexanoic acid, capric acid, lauric acid, isotridecanoic acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, isostearic acid, oleic acid, linoleic acid, Examples thereof include behenic acid, erucic acid, ricinoleic acid, hydroxystearic acid and the like. These may be used alone or in any combination of two or more.

The molar ratio of glycidol to fatty acid in the addition polymerization reaction of glycidol and the above fatty acid is
1-100, preferably 1-50, more preferably 1
It is good to choose in the range of ~ 10.

If the molar ratio is less than 1, mold releasability cannot be imparted to the methacrylic resin, and conversely, the molar ratio is 10
When it is 0 or more, the ratio of the hydrophilic group to the hydrophobic group becomes too high in the polyglycerin fatty acid ester, and the compatibility with the methacrylic resin decreases, which is not preferable.

The addition polymerization reaction of the above fatty acid and glycidol is preferably carried out in the presence of a phosphoric acid-based acidic catalyst and, if necessary, a solvent. The phosphoric acid-based acidic catalyst used here is phosphoric acid or phosphoric acid ester. Specifically, phosphoric acid, phosphoric anhydride, polyphosphoric acid, orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphoric acid such as triphosphoric acid, tetraphosphoric acid, methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid. Phosphate, 2-
Examples thereof include acidic phosphoric acid esters such as ethylhexyl acid phosphate. The acidic phosphoric acid ester may be a monoester body, a diester body or a mixture thereof. Among the catalysts listed above, phosphoric acid and acidic phosphoric acid esters are particularly preferable.

The above catalysts may be used alone or in combination of two or more. The amount of the catalyst used was 0.
It is preferable to select in the range of 01 to 10% by weight. If it is less than 0.01% by weight, the reaction rate is too slow, and if it exceeds 10% by weight, the effect is not reached even if a large amount of the catalyst is used, and an addition polymer of glycidol is by-produced. Absent. In the above range of the amount of catalyst used, 0.1-5
% By weight is particularly preferred. The addition polymerization reaction can be carried out without a solvent, but a solvent may be used. As the solvent that can be used, aromatic hydrocarbons having 6 to 9 carbon atoms, particularly halogenated toluene such as benzene, toluene and trifluorotoluene, aliphatic ketones having 3 to 9 carbon atoms, especially methyl isopropyl ketone , Methyl isobutyl ketone, diethyl ketone, di-isobutyl ketone, and the like. Besides, ethers such as diisopropyl ether are also suitable. These solvents may be used alone or as a mixture of two or more kinds. When a solvent is used, the amount used is preferably as small as possible from the viewpoint of recovery operation after completion of the reaction, and particularly preferably twice the total amount of the reaction raw materials.

The reaction temperature varies depending on the presence or absence of a solvent, the type and amount of the catalyst, and the like, but it is preferably selected in the range of 50 to 180 ° C. If the temperature is lower than 50 ° C, the reaction rate is too slow, and if it exceeds 180 ° C, not only the coloring of the product becomes severe, but also glycidol is decomposed to cause a side reaction, which is not preferable. In the above temperature range, 70 to 160 ° C is preferable, and 140 to 160 ° C is particularly preferable.

The addition polymerization reaction is preferably carried out by mixing a fatty acid, a solvent and a catalyst in a reaction vessel, heating the mixture to the reaction temperature, and then adding glycidol little by little with stirring. The reaction can be carried out continuously or batchwise.

If a solvent is used and its boiling point is below the reaction temperature, it is advantageous to carry out under pressure.
It is desirable to carry out the addition polymerization reaction in an inert gas atmosphere such as nitrogen gas.

By the above reaction, glycidol is addition-polymerized with the fatty acid to produce a polyglycerin fatty acid ester having a higher degree of polymerization. The product is a monofatty acid ester form,
The polyglycerin fatty acid ester is a mixture of di-fatty acid ester body and tri-fatty acid ester body, and according to the above reaction, one having a large content ratio of mono fatty acid ester body is obtained. That is, the polyglycerin fatty acid ester used in the present invention has a content of 70% or more represented by the peak area ratio of the monofatty acid ester compound detected by an ultraviolet absorption detector by a column chromatography analysis method. .

The amount of polyglycerin fatty acid ester used in the present invention is 0.01 to 0.4% by weight,
It is preferably 0.05 to 0.3% by weight.

If the amount added is less than 0.01% by weight, the effect of improving the releasability is not exerted, and if the amount added exceeds 0.04% by weight, mechanical properties and melt viscosity may decrease. . It is of course possible to use a mixture of two or more compounds within the scope of the present invention.

In the present invention, the pentaerythritols and the polyglycene fatty acid ester are 10/90.
When used in a ratio of ˜90 / 10, preferably 25/75 to 75/25, a remarkable synergistic effect appears. Within the range of this ratio, it is selected according to the composition, molecular weight, fluidity and the like of the methyl methacrylate polymer used.

The total amount of the pentaerythritols and the polyglycene fatty acid ester of the fatty acid is 0.02 to 0.5 parts by weight per 100 parts by weight of the methyl methacrylate polymer,
It is preferably 0.05 to 0.2 parts by weight. If the total amount of these is less than 0.02 parts by weight, the mold release performance is insufficient, and the surface layer of the molded product is liable to peel or crack.

On the other hand, when the addition amount exceeds 0.5 parts by weight, the molded product is colored. In addition, excessive mold release agent adheres to the surface of the mold, and the mold becomes undesirably soiled and contaminated. A well-known method can be used to make the composition by incorporating the pentaerythritols and the fatty acid ester of polyglycene into the methyl methacrylate polymer used in the present invention.

For example, it is a method of kneading each component in a molten state, and the melt kneading is only a method of using a kneading device such as a generally used uniaxial or biaxial extruder or various kneaders. Instead, there is a method of directly kneading during a melt processing operation such as injection molding and extrusion molding. In addition, the monomer or syrup containing methyl methacrylate as the main component,
There is a method in which the pentaerythritols and the polyglycene fatty acid ester are added and mixed, and this is polymerized by a known method such as a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, a solution polymerization method.

The methacrylic resin composition of the present invention contains well-known antioxidants such as hindered phenol antioxidants, phosphorus antioxidants and sulfur antioxidants, ultraviolet absorbers and hindered amine photostabilizers. Agents such as weathering agents, flame retardants, colorants, pigments, stabilizers, lubricants, nucleating agents, release agents, or organic polymer materials, inorganic or organic fibrous, powdery, plate-like fillers, etc. One kind or two or more kinds may be added, and further, reinforcing fibers such as glass fibers and inorganic filler may be added depending on the purpose. The methacrylic resin composition of the present invention can be prepared by the equipment and method generally known as a method for preparing a synthetic resin composition.

That is, the necessary components can be mixed, kneaded using a single-screw or twin-screw extruder, extruded into pellets for molding, and then molded. It is also possible to perform it simultaneously with molding.

Additives such as the above-mentioned stabilizers and additives may be added at any arbitrary stage, and it is of course possible to add and mix them just before obtaining the final molded product. Further, the resin composition according to the present invention can be molded by any of extrusion molding, injection molding, compression molding, vacuum molding, blow molding, and foam molding, and particularly in the case of extrusion molding, the effect of the present invention is remarkable. is there.

[0031]

EFFECTS OF THE INVENTION The methacrylic resin composition of the present invention has excellent releasability when molded by using a mold and is excellent in original methacrylic resin as compared with the conventional methacrylic resin. It also has transparency and weather resistance. Therefore, it is suitable for molding a molded product having a complicated shape such as an automobile part such as a meter cover, an optical part such as a video disk and a lens, a lighting part, and an OA equipment part by using a mold.

<Examples> The present invention will be further described with reference to the following examples. The evaluation methods used in the examples are as follows.

(A) Releasability: 25 mm × 7 in an injection molding machine having a capacity of 13 ounces (M-140SJ type, manufactured by each machine manufacturer)
Attach a 6.5 mm x 3.2 mm ASTM test piece mold, molding temperature 260 ° C, injection pressure 80 Kg / cm ² · G,
Mold temperature 60 ℃, 60 seconds cycle, continuous 40
Successful times test piece. It was expressed by the ratio of the number of defective products such as cracks and cracks in the molded product at this time.

(B) Contamination: Visual observation of the fog condition on the mold surface (mirror surface) immediately after the above molding was completed was designated as O when no fog was observed and X when fog was observed. .

(C) Appearance: Contamination and coloration of the molded product were visually observed.

[Reference Example] Stirrer, thermometer, temperature controller,
0.5 mol of stearic acid (284.49 g) and phosphoric acid (purity 85%) were placed in a 4-necked flask with a capacity of 1 liter equipped with a reflux condenser, a dropping cylinder, a nitrogen gas introduction tube and the like.
Product) 0.0622g was charged and the internal temperature was 140 ° C under stirring.
Heated. Then, while maintaining the internal temperature at this temperature and stirring, 3.0 mol (222.24 g) of glycidol was added to 5 mol.
The solution was added dropwise over time, and the reaction was continued until the oxirane concentration in the system became 0.1% or less.

[Example 1] 100 parts of a granular methacrylic resin obtained by suspension polymerization, [SUMIPEX BLO, manufactured by Sumitomo Chemical Co., Ltd.], 0.025 parts of dipentaerythritol tripalmitate and a reference example. Hexaglycerin monostearate (0.025 parts) was mixed with a Henschel type mixer, and then pelletized using a vent type extruder having a screw diameter of 40 mm. The pellets were evaluated.
Table 1 shows the obtained results.

[Examples 2 to 5, Comparative Examples 1 to 4] Dipentaerythritol tripalmitate and the amount of hexaglycerin monostearate obtained in Reference Example were changed as shown in Table 1. The same procedure as in Example 1 was performed. Table 1 shows the obtained results.

[Examples 6 to 8] The same procedure as in Example 2 was repeated except that pentaerythritol tart was changed as shown in Table 1. Table 1 shows the obtained results.

Table 1 Mixing amount (parts by weight) Type (part) Type (part) Releasability Contamination Appearance (% defective) Example 1 A 0.025 E 0.025 7.6 ○ Good 2 A 0.05 E 0.05 6.4 ○ Good 3 A 0.1 E 0.1 5.0 ○ Good 4 A 0.03 E 0.07 6.3 ○ Good 5 A 0.07 E 0.03 6.4 ○ Good 6 B 0.05 E 0.05 6.6 ○ Good 7 C 0.05 E 0.05 6.7 ○ Good 8 D 0.05 E 0.05 6.7 ○ Good Comparative Example 1 None - No - 15.0 ○ good 2 A 0.1 No - 12.3 ○ good 3 No - E 0.1 12.3 ○ good 4 A 0.3 E 0.3 4.4 × slightly yellowish Note) A: dipentaerythritol tripalmitate B: dipentaerythritol hexabehenate C: Monopentaerythritol D: Tripentaerythritol E: Hexaglycerin monostearate obtained in Reference Example (blank space below)

Claims (1)

[Claims] 1. A compound represented by the following formula (I) or (II) with respect to 100 parts by weight of a methyl methacrylate polymer. <Wherein X ¹ , X ² , X ³ , and X ⁴ represent hydrogen or the following partial structural units (III) and (IV)> Embedded image <Wherein X ⁵ , X ⁶ , X ⁷ , X ⁸ , X ⁹ , X ¹⁰ , X ¹¹ and X
¹² is the same as the above X ¹ , X ² , X ³ , and X ⁴ , and n is 0 to 3
A polyglycene fatty acid ester synthesized from at least one selected from pentaerythritols represented by the formula: fatty acid or glycerin fatty acid ester and glycidol at a weight ratio of 10/90 to 90/10 and 0.02 to
A methacrylic resin composition containing 0.5 part by weight.