KR20020032770A - Acrylic resin composition having superior thermal stability - Google Patents

Abstract

PURPOSE: An acryl resin composition and its preparation method are provided, to improve the heat stability without deterioration of the mechanical properties and the flowability by adding a molecular weight controlling agent and vinyl acid simultaneously to the preparation process. CONSTITUTION: The acryl resin composition comprises 85-95 parts by weight of alkyl methacrylate; 5-15 parts by weight of acrylate; 0.2-0.6 parts by weight of a sulfur-containing molecular weight controlling agent; and 20-100 ppm of a sulfur or phosphorus-containing vinyl acid. The acryl resin composition is prepared by suspension polymerization. Preferably the alkyl methacrylate is methyl methacrylate, ethyl methacrylate or butyl methacrylate; the acrylate is methyl acrylate, ethyl acrylate or butyl acrylate; the sulfur-containing molecular weight controlling agent is n-octyl mercaptan, n-dodecyl mercaptan or t-dodecyl mercaptan; and the sulfur or phosphorus-containing vinyl acid is 2-sulfoethyl methacrylate, acrylamidopropanesulfonic acid or 2-sulfopropyl methacrylate.

Description

Acrylic resin composition with excellent thermal stability {ACRYLIC RESIN COMPOSITION HAVING SUPERIOR THERMAL STABILITY}

[Industrial use]

The present invention relates to an acrylic resin composition having excellent thermal stability, and more particularly to an acrylic resin composition having excellent thermal stability while maintaining mechanical properties and fluidity.

[Prior art]

Acrylic resins made of methylmethacrylate (MMA) as the main component are transparent materials that transmit about 85% of light, and have excellent optical properties, weather resistance, electrical and thermal properties, and rigid materials capable of profound color matching. A wide range of coloring is possible and molded products are easily decorated by a wide range of techniques to make molded parts easy, with low water absorption and good dimensional stability. Acrylic resins having the above characteristics have been applied to various fields related to lighting, optics, automobiles, electricity, daily necessities, medicine, signs, and the like. However, due to the generation of gas due to pyrolysis during the extrusion and injection molding of the acrylic resin, molding defects such as silver and bubbles and thermal discoloration are raising the defective rate of the acrylic resin manufacturer.

Therefore, when N-allyl maleimide and methyl methacrylate are copolymerized to produce an acrylic resin having excellent thermal stability (Japanese Patent Publication 1968-9753), a phosphorus thermal stabilizer or phenol Various methods have been proposed, such as a method of adding a series stabilizer (Japanese Patent Laid-Open No. 1989-256551, Japanese Patent Laid-Open No. 1997-116331, Japanese Patent Laid-Open No. 1988-304045).

In addition, when the sulfur-containing materials dodecylmercaptan (DDM: dodecylmercaptane) and n-octyl mercaptane (n-octyl mercaptane) is used as a molecular weight regulator, it has been found that the thermal stability of the acrylic resin is improved (Japanese Patent Publication) 1988-304015), when the molecular weight regulator is excessively used, the molecular weight of the acrylic resin is reduced, it is difficult to secure proper fluidity during extrusion and injection due to increased fluidity, and there is a problem of deteriorating mechanical properties.

In general, sulfuric or phosphorus-containing vinylic acid series is known to show a significant increase in molecular weight with a small amount of input during free radical polymerization (US Pat. No. 5,990,255), but studies on its use are insufficient.

Therefore, the use of dodecyl mercaptan and n-octyl mercapdan improves thermal stability and at the same time maintains the proper balance of molecular weight and fluidity to maintain mechanical properties. Research is needed.

In view of the problems of the prior art, an object of the present invention is to provide an acrylic resin composition capable of maintaining mechanical properties while improving thermal stability.

[Means for solving the problem]

In order to achieve the above object of the present invention, in the acrylic resin composition excellent in the thermal stability produced by suspension polymerization,

a) 85 to 95 parts by weight of alkyl methacrylate;

b) 5 to 15 parts by weight of acrylate;

c) 0.2 to 0.6 parts by weight of sulfur-containing molecular weight regulator; And

d) 20 to 100 ppm of vinyl acid containing sulfur-containing phosphorus

It provides an acrylic resin composition comprising a.

Hereinafter, the present invention will be described in detail.

[Action]

In order to provide an acrylic resin having excellent thermal stability, the sulfur-containing molecular weight regulator and sulfuric or phosphorus-containing vinylic acid are simultaneously added to the acrylic resin suspension polymerization process to maintain mechanical properties and fluidity at an appropriate level. Is adjusted.

The alkyl methacrylate of a) is methyl methacrylate (MMA: methylmethacr ylate), ethyl methacrylate (EMA: ethylmethacrylate), or butyl methacrylate (BMA: buthylmethacrylate).

In addition, the acrylate of b) is methyl acrylate (MA: methylacrylate), ethyl acrylate (EA: ethylacrylate), or butyl acrylate (buthylacrylate).

The sulfur-containing molecular weight regulator of c) serves to improve the thermal stability of the acrylic resin, and usable molecular weight regulators include n-octylmercaptan (NOM: n-octylmercapt ane) and n-dodecylmercaptan (DDM: n 0.2 to 0.6 parts by weight of -dodecylmercaptane) or t-dodecylmercaptane (TDDM) is used.

The vinyl acid of d) contains sulfur or phosphorus and shows a significant increase in molecular weight due to the addition of a small amount during free radical polymerization. Such vinyl acid series includes 2-sulfoethylmethacylate and acrylamidopropane. Sulphonic acid (acrylamidopropa nesulfonic acid) or 2-sulfopropylmethacrylate (2-sulfopropylmethacylate) is preferable, and the range of charge is 20 to 100 ppm.

The present invention produced an acrylic resin having excellent thermal stability and maintaining proper fluidity and mechanical properties at the same time by using a sulfuric acid or a phosphoric acid containing vinyl acid and a molecular weight regulator in the suspension polymerization process at the same time.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, an Example is for illustrating this invention and is not limited only to these.

EXAMPLE

The physical properties of the acrylic resin used in the following examples of the present invention were obtained by taking 10 g of beads in an aluminum container and keeping them in an oven at 250 ° C. for 4 hours, and then determining the weight loss ratio. The fluidity was measured and evaluated by ASTM-D1238 under the conditions of kg.

Example 1

94 parts by weight of methyl methacrylate (MMA) and 6 parts by weight of ethyl acrylate (EA) in 100 parts by weight of a monomer mixture of 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate (1,1, 0.25 parts by weight of 3,3-tetramethyl butyl peroxy 2-ethylhexanoate, 0.22 parts by weight of n-octylmercaptane (NOM), 20 ppm of 2-sulfoethyl methacrylate (SEM) 10 kg of a polymerization raw material mixed with 0.1 parts by weight and 15 kg of pure water containing a small amount of a suspending agent, a suspension stabilizer and a suspension stabilizer were added to a 40 L reactor with a stirrer and polymerized at 70 ° C. for 3 hours, and then 120 ° C. The reaction was terminated by further polymerization for 1 hour. After completion | finish of a polymerization reaction, the polymer of the bead state was obtained through cooling, filtration, and a drying process. The fluidity and thermal stability of the polymer prepared in this example were measured according to the above-described method for measuring heat loss and fluidity. As a result, MI (g / 10 min) was 6.0 g / 10 min, and the heating loss was 45.5%.

Examples 2-3 and Comparative Examples 1-3

Preparation of Examples 2 to 3 and Comparative Examples 1 to 3 was carried out in the same manner as in Example 1, but was polymerized in the composition shown in Table 1 below to obtain a bead polymer. The polymerization stability according to the SEM and NOM content of the polymers prepared as described above and the thermal stability and fluidity of the beads after polymerization were measured and the results are shown in Table 2.

TABLE 1

division Resin composition (parts by weight) Monomer mixture Molecular weight regulator (NOM,%) Vinyl acid (SEM, ppm) Example 2 MMA 94 + EA 6 = 100 0.37 50 Example 3 MMA 94 + EA 6 = 100 0.52 100 Comparative Example 1 MMA 94 + EA 6 = 100 0.22 0 Comparative Example 2 MMA 94 + EA 6 = 100 0.37 0 Comparative Example 3 MMA 94 + EA 6 = 100 0.52 0

TABLE 2

division MI (g / 10 min) Heating loss (%) Example 1 6.0 45.5 Example 2 4.8 32.2 Example 3 4.0 14.8 Comparative Example 1 7.5 58.2 Comparative Example 2 10.2 29.9 Comparative Example 3 12.1 15.2

Through the MI and the heat loss of the examples of Table 2 and the comparative example, the polymers of Examples 1 to 3 simultaneously administered with the vinyl acid and the molecular weight modifier were lower than the polymer of the comparative example administered with the molecular weight modifier without the addition of the vinyl acid. This excellence could be confirmed.

As described through the above Examples and Comparative Examples, the present invention has an effect of providing an acrylic resin having excellent thermal stability while maintaining mechanical properties and fluidity than conventional acrylic resins.

Claims (6)

In the acrylic resin composition excellent in the thermal stability manufactured by suspension polymerization, a) 85 to 95 parts by weight of alkyl methacrylate; b) 5 to 15 parts by weight of acrylate; c) 0.2 to 0.6 parts by weight of sulfur-containing molecular weight regulator; And d) 20 to 100 ppm of vinyl acid containing sulfur or phosphorus Acrylic resin composition comprising a. The acrylic resin composition according to claim 1, wherein the alkyl methacrylate of a) is selected from the group consisting of methyl methacrylate, ethyl methacrylate, and butyl methacrylate. The acrylic resin composition according to claim 1, wherein the acrylate of b) is selected from the group consisting of methyl acrylate, ethyl acrylate, and butyl acrylate. The acrylic resin composition according to claim 1, wherein the sulfur-containing molecular weight regulator of c) is selected from the group consisting of n-octyl mercaptan, n-dodecyl mercaptan, and t-dodecyl mercaptan. The acrylic resin according to claim 1, wherein the sulfuric or phosphorus-containing vinyl acid of d) is selected from the group consisting of 2-sulfoethyl methacrylate, acrylamidopropanesulphonic acid, and 2-sulfopropyl methacrylate. Composition. Adding 100 parts by weight of 0.2 to 0.6 parts by weight of a molecular weight regulator and 20 to 100 ppm of vinylic acid to 100 parts by weight of a monomer mixture of methyl methacrylate and ekylate, followed by suspension polymerization at 70 ° C. for 3 hours and 120 ° C. for 1 hour. The manufacturing method of the acrylic resin excellent in thermal stability.