KR20030010239A - Thermoplastic Resin Compositions with Good Extruding Ability - Google Patents

Abstract

PURPOSE: Provided is a thermoplastic resin composition excellent in extrusion-stability and extrusion-processability, which dose not have the change of extrusion amount, the lack of thickness uniformity, and scratches. CONSTITUTION: The thermoplastic resin composition comprises: 20-60pts.wt. of a graft copolymer obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound into a rubber polymer, wherein the graft copolymer has a graft rate of 50-100% and a weight average molecular weight of 50,000-100,000; 40-80pts.wt. of a copolymer obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound; 0.1-2pts.wt. of a divalent metal compound; 0.1-30pts.wt. of an ultrahigh molecular weight copolymer obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound and having an average molecular weight of 1,000,000-5,000,000.

Description

Thermoplastic Resin Compositions with Good Extruding Ability

Field of invention

The present invention relates to a thermoplastic resin composition excellent in extrusion processability. More specifically, the present invention relates to decomposition, cross-linking, gelation, networking, or carbonization of a resin due to retention during extrusion by adding an ultra high molecular weight SAN and a metal salt to the thermoplastic resin composition. The present invention relates to a thermoplastic resin composition having excellent extrusion processability, which greatly increases stability, has no fluctuation in extrusion amount, is uniform in product thickness, and has no surface problems such as die-line.

Background of the Invention

Generally, a resin composition is obtained by mixing and processing an appropriate additive according to the purpose of use of a raw material resin. The resin composition in the form of pellets prepared as described above is manufactured into a molded article having a shape to be used through ordinary injection, extrusion, or compression molding. In such a molding process in which the resin is processed into a shape corresponding to the end use, the injection and extrusion molding methods mainly used for processing the thermoplastic resin compound are performed by a continuous process or a continuous circulation process. At this time, the resin composition is transferred forward through the empty space between the screw and the cylinder of the extruder or the injection machine, and the melt or plasticization proceeds due to the friction between the resin and the cylinder wall and the heat history received from the heater of the cylinder wall, thereby extruder die and gloss. The molded product is manufactured in the shape of a mold by producing a sheet through a rolling roll or by cooling and solidifying the mold in a mold through an injection nozzle.

In the melting or plasticization process of such a resin, the heat history and flow of the resin are locally different, and at a certain part, the resin is stagnant or vortices, resulting in excessive heat history or long time heat history. The resin may be changed in different shapes, different compositions or different appearances and colors. Some of these components are made into hard particles (hard spots or fish eyes) or hard agglomerates due to chemical or physical changes such as crosslinking, meshing, carbonization or aggolomeration, extrusion sheets or forming. The protruding shape of the solidified solids on the product or the flow of such agglomerate on the surface of the product resembles a scratch line from a silver streak or a die, which reduces the appearance quality. . In addition, the sheet-like products are prone to fatal appearance defects because these parts protrude more easily through stretching in the vacuum forming process, which is a secondary processing process. This aspect shows a tendency to deepen when the size or size of the processing equipment is large. Meanwhile, in the case of general thermoplastic resins, there is a problem in that the extrusion workability of the resin itself is insufficient, so that variation in extrusion amount, lack of uniformity in thickness, and scratches (Die Line) occur a lot during extrusion processing.

Many studies have been conducted to solve the above problems occurring during processing of the resin to improve extrusion stability and processability. Japanese Patent Laid-Open No. 6-16897 discloses a method of applying an antioxidant compound such as a hindered phenolic stabilizer during resin processing. The addition of an antioxidant compound has the effect of improving the color and physical properties of the resin by inhibiting the oxidation reaction during processing, but there is a limit that can not maintain excellent stability under excessive thermal history due to retention or retention during processing.

Korean Patent Application No. 93-18486 discloses a method of using a low molecular weight polyethylene wax, ethylene bis steamide or a metal soap based lubricant compound in an excessive amount during resin processing. According to the patent application, the participating lubricant compound reduces the friction between the metal and the resin during processing, thereby improving workability. However, it also does not improve the crosslinking and carbonization of the resin under excessive heat history, which is stagnant for a long period of time, and if an excessive amount of a lubricant is used, an increase in low molecular weight material which is easy to decompose decreases the color stability of the resin, and vacuum molding. The problem arises that the stretching characteristics of the resin in the secondary processing step, such as deterioration.

In order to solve the above problems, Korean Patent Application Nos. 97-0075567, 98-062769 and 99-003735 are salts of divalent metals, chlorides of divalent metals, A method of adding at least one compound selected from the group consisting of carbonates and oxides of divalent metals or mixtures thereof is disclosed. However, it does not improve extrusion workability such as fluctuation of extrusion amount, lack of thickness uniformity, and die line during extrusion.

In order to solve the above problems, the present inventors add a metal compound and an ultra-high molecular weight SAN copolymer, and do not cause a poor appearance of the resin even when stagnant or staying for a long time, and at the same time, fluctuations in extrusion amount, lack of uniformity in thickness, and scratches It is to develop a thermoplastic resin composition excellent in extrusion stability and workability without developing.

An object of the present invention is to provide a thermoplastic resin composition excellent in extrusion stability that does not cause a poor appearance of the resin even when stagnant or dwell for a long time in the extrusion process.

Another object of the present invention is to provide a thermoplastic resin composition having excellent extrusion workability without fluctuations in extrusion amount, lack of uniformity in thickness, scratching, and the like.

The above and other objects of the present invention can be achieved by the present invention described below. Hereinafter, the content of the present invention will be described in detail.

The thermoplastic resin composition excellent in the extrusion workability of the present invention comprises (A) 20-60 parts by weight of a graft copolymer obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound in a rubbery polymer; (B) 40-80 parts by weight of a copolymer obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound; (C) 0.1-2 parts by weight of a divalent metal compound; And (D) 0.1-30 parts by weight of an ultra high molecular weight copolymer obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound, and detailed descriptions of each of these components are as follows.

(A) Graft Copolymer

The graft copolymer (A) used in the present invention is obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound in a rubbery polymer. The rubbery polymer includes polybutadiene, styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, and the like, and the vinyl cyanide compound includes acrylonitrile, methacrylonitrile, and the like. Methyl styrene and vinyl toluene.

In particular, it is preferable to use a copolymer obtained by adding one aromatic vinyl monomer and 30-70 wt% of an unsaturated nitrile monomer to 30-70 wt% of butadiene rubber, and graft copolymerization thereof. The rubber is 500-3,500 mm in size of 90% or more of rubber particles, and 50% or more of gel content is used. The graft copolymer has a graft rate of 50-100% and a weight average molecular weight of 50,000-100,000.

The graft copolymer (A) is used in an amount of 20 to 60 parts by weight based on the thermoplastic resin composition.

(B) copolymer

The copolymer (B) used for this invention is obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound. In particular, it is preferable to copolymerize 50-90 weight% of aromatic vinyl monomers and 80-50 weight% of unsaturated nitrile monomers. The copolymer (B) is used in an amount of 40 to 80 parts by weight of the thermoplastic resin composition.

(C) divalent metal compound

The divalent metal compound (C) is added to improve the processing stability of the resin. The compound reacts with an active functional part in the raw material resin, or an ingredient causing appearance problems in the raw material resin polymerization or additives used in the production of the final resin. They are transformed into non-reactive or weakly active moieties or compounds. The divalent metal compounds used in the present invention include salts of divalent metals, chlorides of divalent metals, carbonates of divalent metals, and oxides of divalent metals. Examples include magnesium carbonate, calcium carbonate, zinc chloride, magnesium chloride, calcium chloride, zinc oxide, magnesium oxide, calcium oxide and the like.

The divalent metal compound (C) is used in an amount of 0.1-2 parts by weight of the thermoplastic resin composition.

(D) Ultra high molecular weight copolymer

Ultra high molecular weight copolymer (D) serves to improve the extrusion workability by solving problems such as fluctuation of extrusion amount, lack of uniformity of thickness, scratches (Die Line) during the extrusion process. In the present invention, by adding the divalent metal compound (B) and the ultra-high molecular weight copolymer to the thermoplastic resin composition, it is excellent in extrusion stability that does not cause poor appearance appearance of the resin even during a long period of stagnation or retention, and excellent in extrusion workability It constitutes a resin composition.

The ultrahigh molecular weight copolymer (D) used in the present invention is an ultrahigh molecular weight copolymer obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound. In particular, it is preferable to use an ultrahigh molecular weight copolymer having a PS reduction weight average molecular weight of 1 million to 5 million as a copolymer obtained by copolymerizing 50-90% by weight of an aromatic vinyl monomer and 10-50% by weight of an unsaturated nitrile monomer. The ultra high molecular weight copolymer (C) is used in an amount of 0.1-30 parts by weight of the thermoplastic resin composition.

The thermoplastic resin composition of the present invention may be additives such as heat stabilizers, antioxidants, lubricants, lubricants, mold release agents, light and ultraviolet stabilizers, flame retardants, antistatic agents, colorants, fillers, impact modifiers, etc. without departing from the object of the invention. It may further include, it is also possible to use other resin or other rubber components together.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

Preparation and specifications of (A) graft copolymer, (B) copolymer, (C) divalent metal compound and (D) ultra high molecular weight copolymer used in the following Examples and Comparative Examples are as follows.

(A) Graft Copolymer

Butadiene rubber latex having a particle size of 0.3 μm was added so that the total butadiene content was 50 parts by weight, 150 parts by weight of deionized water, 0.9 parts by weight of rosin soap, 0.3 parts by weight of cumene hydroperoxide, and mercaptan-based 0.2 parts by weight of the chain transfer agent and 0.3 parts by weight of glucose were added to maintain the internal temperature at 70 ° C. 35 weight part of styrene and 15 weight part of acrylonitrile were dripped here for 3 hours, and superposition | polymerization was advanced by redox initiation, and the styrene- acrylonitrile- butadiene graft copolymer latex was produced. The latex was solidified in 1.5% magnesium sulfate aqueous solution and dried to prepare a powdered styrene-acrylonitrile-butadiene graft copolymer resin.

(B) copolymer

Cheil Industries' styrene-acrylonitrile copolymer (trade name: SAN HR-5330) was used.

(C) divalent metal compound

Magnesium oxide (MgO) was used.

(D) Ultra high molecular weight copolymer

Styrene monomer 71% by weight, acrylonitrile monomer 29% by weight, ion-exchanged water 150 parts by weight, tricalcium phosphate 0.4 parts by weight, carboxylic acid-based anionic surfactant 0.03 parts by weight, polyoxyethylene alkyl ether phosphate ester and After adding 0.001-1% by weight of 2,2'-azobisisobutylonitrile as an initiator was mixed, the reactor was completely sealed and sufficiently stirred to disperse, and the temperature of the reactor was raised to polymerize at 75 ° C for 3 hours, It heated up at 120 degreeC again and superposed | polymerized for 3 hours. After the polymerization was completed, the inside of the reactor was cooled to room temperature to terminate the reaction, and the obtained polymer was washed, dehydrated and dried to obtain a bead-like copolymer. The weight average molecular weight of the said ultrahigh molecular weight copolymer was 4 million.

Example 1-2

Each component was added as shown in Table 1, uniformly mixed with a Henschel mixer, and then extruded into a twin screw extruder to form pellets. The prepared pellet was extruded to prepare a physical specimen.

The prepared specimens were kneaded at 260 ° C., 10 RPM for 1 hour using a kneading apparatus of Torque Rheometer manufactured by Haake, Germany, and observed the change in torque. The torque increase (ΔTQ) was calculated by comparing the minimum torque (typically the torque after 20 minutes) and the torque after 1 hour after melting of the resin, and the degree of processing stability was evaluated relative thereto. . In the case where the torque was continuously decreased, the torque reduction (ΔTQ) was obtained by comparing the torque when 1 hour had elapsed with the torque when 20 minutes had passed after kneading. If ΔTQ is greater than 0, crosslinking progresses, so the higher this value, the lower the stability of processing. If ΔTQ is 0 or near 0, there is little change in the resin during processing, which means that the processing stability is good. . In addition, when the negative value which is less than 0 has a negative value, since decomposition | disassembly of resin advances, it shows that process stability fell. The method for obtaining ΔTQ is as follows, and the results are shown in Table 1.

ΔTQ (torque increase) = (torque of resin after 1 hour min torque) or

ΔTQ (torque reduction) = (torque of resin after 1 hour-torque after 20 minutes)

In addition, by using a sheet extruder having a screw diameter of 120 mm and a width of 1,200 mm of a T-Die, the sheet having a thickness of 3 mm was extruded at 230 ° C. for about 12 hours. The extrusion workability was evaluated by observing the variation of the amount, the variation of the thickness, and the surface state including the die-line, and the results are shown in Table 1.

Comparative Example 1-3

In Comparative Example 1, the ultra high molecular weight copolymer (D) was not used, and in Comparative Example 2, the divalent metal compound (C) was not used. In Comparative Example 3, the divalent metal compound (C) and the ultrahigh molecular weight were used. Not all copolymers (D) were used. As described in Table 1, except that each component was changed was carried out in the same manner as in Example 1-2, the results are shown in Table 1.

Example Comparative example One 2 One 2 3 Crude (wt%) (A) Graft Copolymer 30 30 30 30 30 (B) copolymer 66.5 66.5 70 60 60 (C) divalent metal compound 0.3 0.5 0.5 0 0 (D) Ultra high molecular weight copolymer 3 3 0 3 0 Properties Extrusion stability Increase or decrease of torque (ΔTQ) 0 -5 -5 +80 +70 Extrusion workability Extrusion amount fluctuation ◎ ◎ × ○ × Thickness uniformity ◎ ◎ × ○ × Die-line ◎ △ × △ ×

* ◎: Very good, ○: Excellent, △: Normal, ×: Poor

From the results of Table 1, when the bivalent metal compound (C) and the ultrahigh molecular weight copolymer (C) were used together, the increase and decrease of torque was close to zero, and the extrusion amount variation, thickness uniformity, and die-line were all excellent. As a result, it can be seen that extrusion stability and extrusion workability are simultaneously improved. That is, when only the bivalent metal compound (C) is added as in Comparative Example 1, the extrusion stability is excellent, but extrusion workability is lowered, and when only the ultrahigh molecular weight copolymer (C) is added as in Comparative Example 2, the extrusion operation is performed. It is excellent in terms of performance, but the torque increase and decrease is +80, which reduces the extrusion stability. In addition, when the bivalent metal compound (C) and the ultrahigh molecular weight copolymer (C) were not used as in Comparative Example 3, it can be seen that both extrusion stability and extrusion workability were deteriorated.

By using a divalent metal compound and an ultra-high molecular weight copolymer, the present invention does not cause a poor appearance of the resin even when stagnant or dwells for a long time in the extrusion process, while fluctuations in extrusion amount, lack of uniformity in thickness, and scratches It has the effect of providing a thermoplastic resin composition excellent in extrusion stability and extrusion workability.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (5)

(A) 20-60 parts by weight of a graft copolymer obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound in a rubbery polymer; (B) 40-80 parts by weight of a copolymer obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound; (C) 0.1-2 parts by weight of a divalent metal compound; And (D) 0.1-30 parts by weight of an ultra high molecular weight copolymer having a weight average molecular weight of 1,000,000-5,000,000 obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound. The thermoplastic resin composition excellent in extrusion processability characterized by consisting of. The thermoplastic resin composition according to claim 1, wherein the graft copolymer (A) has a graft ratio of 50-100% and a weight average molecular weight of 50,000-100,000. The thermoplastic resin composition of claim 1, wherein the rubbery polymer is a butadiene-based rubber having a size of 90% or more of rubber particles of 500-3,500 mm 3 and a gel content of 50% or more. The extrusion processability according to claim 1, wherein the divalent metal compound (C) is selected from the group consisting of salts of divalent metals, chlorides of divalent metals, carbonates of divalent metals and oxides of divalent metals. This excellent thermoplastic resin composition. The method of claim 1, wherein the resin composition further comprises a heat stabilizer, antioxidant, lubricant, lubricant, mold release agent, light and ultraviolet stabilizer, flame retardant, antistatic agent, colorant, filler, impact modifier excellent in extrusion processability, characterized in that Thermoplastic resin composition.