KR20170142763A - Acrylic processing aid and vinyl chloride resin composition containing thereof - Google Patents

Abstract

The present invention relates to an ultrahigh molecular weight acrylic processing aid which improves foaming formability of a vinyl chloride resin and a vinyl chloride resin composition containing the same. The processing aid containing an ultrahigh molecular weight acrylic copolymer lowers foaming specific gravity, keeps the cell size small and uniform and improves foaming formability by having excellent surface properties when the vinyl chloride resin is foamed and molded.

Description

TECHNICAL FIELD The present invention relates to an acrylic processing aid and a vinyl chloride resin composition containing the same,

The present invention relates to an ultrahigh molecular weight acrylic-based processing aid and a vinyl chloride resin composition containing the same, which improves foaming moldability of a vinyl chloride resin.

The vinyl chloride resin is inexpensive, hardness is easy to control, and it can be applied to most processing equipments, thus various applications are available. In addition, it is widely used in various fields because it provides a molded body having excellent physical and chemical properties.

The vinyl chloride resin composition widely used has various disadvantages in terms of impact strength, workability, thermal stability, and heat distortion temperature. Accordingly, additives for complementing these have been developed and used. Examples of additives for the vinyl chloride resin composition include an impact modifier, a processing aid, a stabilizer, a filler, and the like.

In recent years, attention has been paid to foam molding as means for reducing the weight of vinyl chloride resin and lowering the cost of molded articles. However, when the polyvinyl chloride-based resin is foam-molded, sufficient drawing and melt strength can not be obtained, resulting in poor appearance of molded articles, large foam cells and unevenness, resulting in low expansion ratio. Therefore, in order to overcome such disadvantages, a method of adding a high-molecular acrylic-based processing aid containing an acrylic copolymer mainly composed of methyl methacrylate as a main component to a vinyl chloride resin with a foaming agent is generally used.

However, when a high molecular weight acrylic-based processing aid is used, the workability and dispersibility are poor due to high molecular weight and high melt viscosity. For example, there is a problem that a surface defect such as a die mark, a flow mark, a fish-eye or the like or a specific gravity difference depending on a molded body part is largely generated.

U.S. Patent No. 6,391,976, "Processing aid for foam molding use and vinyl chloride resin composition containing the same" U. S. Patent No. 6,221, 966, "Vinyl chloride resin composition"

The present inventors have conducted various studies to solve the above problems. As a result, it has been found that when an ultra high molecular weight acrylic copolymer is used in the preparation of a processing aid, not only the foaming efficiency with the vinyl chloride resin is enhanced, but also the foamability and moldability .

Accordingly, an object of the present invention is to provide an acrylic-based processing aid capable of improving foam formability of a vinyl chloride resin.

Another object of the present invention is to provide a process for producing the acrylic processing aid.

It is still another object of the present invention to provide a vinyl chloride resin composition comprising the acrylic processing aid.

In order to achieve the above object, the present invention is a copolymer in which a methyl methacrylate monomer and a C1-C18 alkyl acrylate monomer are crosslinked by a crosslinking agent to a methyl methacrylate monomer, and the crosslinked copolymer Is copolymerized with 70 to 90% by weight of methyl methacrylate and 10 to 30% by weight of C1 to C18 alkyl acrylate within a total weight of 100% by weight of the monomers and has a weight average molecular weight of 10 million g / mol or more And an ultrahigh molecular weight acrylic-based processing aid.

The present invention also provides a process for polymerizing the ultrahigh molecular weight acrylic type processing aid in two steps.

Also provided is a vinyl chloride resin composition comprising the ultrahigh molecular weight acrylic processing aid.

The processing aid comprising the ultrahigh molecular weight acrylic copolymer according to the present invention is effective not only in lowering the specific gravity of foam and in making the cell size smaller and more uniform in the foam molding of the vinyl chloride resin but also in improving the foam formability .

Hereinafter, the present invention will be described in more detail.

Ultrahigh molecular weight acrylic processing auxiliary

The acrylic processing aid according to the present invention is a copolymer obtained by crosslinking a methyl methacrylate monomer with a crosslinking agent to a copolymer of methyl methacrylate and C1 to C18 alkyl acrylate monomers, wherein the weight of the crosslinked copolymer And an average molecular weight of 10 million g / mol or more.

When the molecular weight of the acrylic-based processing aid is small in the production of a foamed molded article using a vinyl chloride resin, the foamed specific gravity is high and the cell structure is not densified and the surface characteristics are lowered. Accordingly, the present invention relates to a process for producing an acrylic-based processing aid, which comprises applying an ultrahigh molecular weight acrylic copolymer having a weight average molecular weight of at least 10 million g / mol, and preferably at least 10,000,000 to 30,000,000 g / mol, .

The acrylic processing aid is prepared by copolymerizing methyl methacrylate and an alkyl acrylate of C1 to C18. In this case, the molecular weight is controlled by using a crosslinking agent together with the two-stage polymerization, So that an ultra high molecular weight having a weight average molecular weight of 10 million g / mol or more can be achieved.

The monomer used for the copolymerization is preferably copolymerized at a content ratio of 70 to 90% by weight of methyl methacrylate and 10 to 30% by weight of C1 to C18 alkyl acrylate based on 100% by weight of the total monomers .

If the content of the methyl methacrylate is out of the above range, there is a problem that the processability and moldability of the vinyl chloride resin are lowered due to the deterioration of the overall physical properties.

The C1 to C18 alkyl acrylates used herein may be any one selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, And preferably butyl acrylate.

When the content of the C1 to C18 alkyl acrylate is less than the above range, it is difficult to expect a reduction in the melting time and a reduction in the amount of generated emulsion due to the use of the processing aid. On the other hand, The pressure may be decreased to lower the processability, increase the specific gravity of the foam, lower the cell uniformity, and lower the foam formability.

Particularly, as the crosslinking agent used for improving the molecular weight, 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, At least one member selected from the group consisting of acrylate, allyl methacrylate, trimethylolpropane triacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, ethylene glycol dimethacrylate, and divinylbenzene, Preferably, trimethylolpropane triacrylate is used.

The content of the crosslinking agent is preferably 0.05 to 1 part by weight based on 100 parts by weight of the total weight of the monomers. When the cross-linking agent is added to the monomer mixture in an amount of less than 0.05 part by weight, the effect of improving the molecular weight can not be expected. On the other hand, when the cross-linking agent is added in an amount exceeding 1 part by weight, The cell uniformity is lowered, and the foam formability is lowered.

Process for preparing ultrahigh molecular weight acrylic type processing aid

The ultrahigh molecular weight acrylic type processing aid as described above can be prepared through two stages of polymerization.

Specifically, the acrylic processing aid comprises a primary polymerization step of copolymerizing a methyl methacrylate monomer and an alkyl acrylate monomer of C1 to C18; And

And a second polymerization step of adding a crosslinking agent to methyl methacrylate and the copolymer to prepare a crosslinked copolymer.

In this case, methyl methacrylate can be used in the first polymerization and the second polymerization, and is used in 60 to 89% by weight in the first polymerization step and 1 to 10% by weight in the second polymerization step. As a result, 90 to 99% by weight of the total monomer mixture and 1 to 10% by weight in the second polymerization step can be added in the first polymerization step within a total weight of 100% by weight of the total monomers to prepare an acrylic processing aid .

By the above two-step polymerization process, ultrahigh molecular weight can be achieved. Preferably, after the first polymerization step, the copolymer has a weight average molecular weight of 3,000 to 8,000,000 g / mol, and after the secondary polymerization step, The weight average molecular weight of the copolymer is 10 million g / mol or more. If the molecular weight of the copolymer produced after the first polymerization step is less than the above range, ultrahigh molecular weight of 10 million g / mol or more can not be achieved even after the secondary polymerization.

The adjustment of the molecular weight is achieved through the adjustment of the starting point of the second polymerization step.

That is, the starting point of the secondary polymerization step is preferably a polymerization conversion ratio of 70 to 90% in the primary polymerization step. If the polymerization conversion rate does not reach 70%, initiation of the secondary polymerization tends to result in insufficient increase of the molecular weight and low foaming properties. If the polymerization conversion rate exceeds 90% and the secondary polymerization starts, sufficient molecular weight increase effect It can not be ensured.

The primary polymerization and the secondary polymerization described above can be carried out by a method such as emulsion polymerization, suspension polymerization and solution polymerization used for the production of a copolymer, and it is most preferable to carry out emulsion polymerization . It is needless to say that conventional emulsifiers, polymerization initiators, oxidation-reduction catalysts and the like can be used for the production of the copolymer.

According to one embodiment of the present invention, 95% by weight of a monomer mixture comprising methyl methacrylate and an alkyl acrylate compound is first polymerized in the presence of a water-soluble initiator and an emulsifier; In addition, 5 wt% of methyl methacrylate is subjected to a secondary polymerization in the presence of a water-soluble initiator and an emulsifier to prepare a copolymer latex.

The ultrahigh molecular weight acrylic type processing aid according to another embodiment of the present invention may be prepared into a latex state, followed by agglomeration, dehydration and drying to obtain a powdery state, and preferably acrylic nano-particles. In order to control the particle size of the acrylic nanoparticles, an additional amount of an emulsifier (or a surfactant) and a polymerization initiator may be added to the above composition. In addition, in the emulsion polymerization, a redox catalyst commonly known in the art, An additive such as an antioxidant, a modifier, an activator, ionized water, and the like.

Examples of the polymerization initiator include, but are not limited to, inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium persulfate, and hydrogen peroxide; t-butyl peroxide, cumene hydroperoxide, p-menthol hydroperoxide, di-t-butyl peroxide, t-butyl cumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, dibenzoyl peroxide Organic peroxides such as oxides, 3,5,5-trimethylhexanol peroxide, t-butyl peroxyisobutyrate; Nitrogen compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, and azobisisobutyric acid (butyl acid) methyl.

Examples of the emulsifier include, but are not limited to, anionic emulsifiers such as aliphatic esters, alkylbenzenesulfonates, alkylphosphate salts, dialkylsulfosuccinates, potassium stearate salts and sodium laurylsulfonate, polyoxyethylene alkyl ethers , Alkylamine esters and the like can be used alone or in combination of two or more.

The emulsifier and the polymerization initiator may affect physical properties such as particle size, particle size distribution and the like of a substance produced depending on the content of the polymerization reactant. Specifically, when the content of the emulsifier and the polymerization initiator in the polymerization reaction product is in a certain range, the particle size of the substance to be produced becomes smaller as the content is increased, and as the content is smaller, the particle size of the produced substance may become larger have.

However, when an excessive amount of the emulsifier is added to the reactant, the emulsifier itself becomes an impurity and agglomerates to increase the size of the particles irregularly. When an excessive polymerization initiator is added to the reactant, the polymerization initiator does not participate in the reaction, And the particle size can be irregularly increased. Therefore, in order to produce a uniform range of nanoparticle products, it is important to adjust the appropriate content range of emulsifier and polymerization initiator.

Thus, as described above, the crosslinked acrylic nano-particle composition according to an embodiment of the present invention is prepared by mixing 100 parts by weight of the mixture containing methyl methacrylate and alkyl acrylate monomers with 1.0 part by weight to 3.5 parts by weight And 0.1 part by weight to 0.25 part by weight of a polymerization initiator, whereby the particle size of the crosslinked acrylic nanoparticles can be controlled.

The redox catalyst may be, for example, sodium formaldehyde sulfoxylate, ferrous sulfate, disodium ethylenediamine tetraacetate, and cupric sulfate, and may be used in an amount of 0.01 to 0.1 parts by weight per 100 parts by weight of the monomer mixture. Parts by weight.

The molecular weight regulator is not particularly limited, and examples thereof include mercaptans such as a-methylstyrene dimer, t-octenyl mercaptan, n-dodecyl mercaptan and octyl mercaptan; Halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, and methylene bromide; Containing sulfur compounds such as tetraethyldiallyldisulfide, dipentamethylenediuramydisulfide, and diisopropylkantogen disulfide, and may be used in an amount of 0.1 part by weight to 3 parts by weight based on 100 parts by weight of the monomer mixture.

Activators include, but are not limited to, at least one selected from sodium hydrogensulfate, sodium formaldehyde sulfoxylate, sodium ethylenediamine tetraacetate, ferrous sulfate, lactose, dextrose, sodium lorolene, and sodium sulfate. May be added in the range of 0.01 to 0.15 parts by weight based on 100 parts by weight of the total of monomers in each step.

The polymerization can be carried out at 40 to 80 ° C for 2 to 12 hours.

Thereafter, additionally, the antioxidant may be added to the copolymer latex and then solidified. Methods for coagulating the copolymer latex are well known to those skilled in the art to which the present invention pertains. For example, the methyl methacrylate-alkyl acrylate copolymer resin prepared above may be agglomerated with calcium chloride. The coagulated copolymer can be dehydrated and dried in a conventional manner to obtain a processing aid in powder form.

Such an acrylic processing aid can be used as a processing aid in the foaming molding of a vinyl chloride resin. In addition to lowering the specific gravity of the foam and making the cell size smaller and more uniform, Thereby increasing the melt pressure of the vinyl chloride resin composition and improving the processability.

This is because not only the chemical stability of the crosslinked acrylic processing aid according to one embodiment of the present invention is increased by the crosslinking but also the nano-sized particle size, thereby increasing the specific surface area and increasing the interface between the particles and the vinyl chloride resin It is conceivable to provide a nucleating site between the epoxy resin and the epoxy resin and to improve the processability and foam moldability of the vinyl chloride resin composition containing the epoxy resin.

Vinyl chloride resin  Composition manufacturing

Specifically, the acrylic processing aid according to the present invention is added in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the vinyl chloride resin, and various molded articles are produced through foam molding.

If the content of the acrylic processing aid is less than the above range, the processability, formability and thermal stability of the processing aid are low, resulting in deterioration of the quality of the produced molded article. Conversely, if the content exceeds the above range, As the mechanical and chemical properties are rather deteriorated, they are appropriately used within the above range.

If necessary, various additives commonly used in this field may be further included. Examples of the additive include heat stabilizers, lubricants, impact modifiers, plasticizers, UV stabilizers, flame retardants, colorants, fillers, flame retardants, antimicrobials, mold release agents, heat stabilizers, antioxidants, light stabilizers, compatibilizers, dyes, , Additives such as a binder, a filler, a plasticizer, an impact modifier, an admixture, a colorant, a stabilizer, a lubricant, an antistatic agent, a pigment and a flame retardant may be added alone or in admixture of two or more.

The foaming molding using the vinyl chloride resin composition is not particularly limited in the present invention, and the known method is followed.

The foamed product obtained by foam molding has improved foam expansion ratio and stability of the foamed cell during foaming, so that a foam having a low specific gravity of 0.4 to 0.5 g / cm 3 can be obtained, and a uniform foamed cell is obtained.

The vinyl chloride resin composition to which the acrylic processing aid of the present invention is applied can shorten the melting time while maintaining the inherent physical properties of the vinyl chloride resin and has excellent processing stability. Particularly, it is most suitable because it can reduce the occurrence of fish-eye and flow mark in extrusion processing and knife rendering processing, and can be applied variously to the manufacture of various kinds of molded articles. The molded article to which the processing aid of the present invention is applied has an advantage of excellent appearance and secondary processability such as gloss, surface smoothness and the like.

The vinyl chloride resin composition may be extruded and formed into a pellet. The resin composition may be molded into a finished product such as wire covering, synthetic leather, tube, food packaging, toy, wallpaper, glove and the like.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Example  1 to 5, Comparative Example  1 to 6: Preparation of acrylic type processing aid

< Example  1>

1) Primary polymerization step

First, a reactor of a four-necked flask equipped with a stirrer, a thermometer, a nitrogen inlet, and a circulating condenser was prepared, and 100 parts by weight of ionized water (DDI water), 0.002 part by weight of ferrous sulfate, 0.04 part by weight of disodium ethylenediaminetetraacetate was added, and the temperature inside the reactor was maintained at 40 占 폚 under a nitrogen atmosphere. 70 parts by weight of ionized water, 0.60 part by weight of sodium lauryl sulfate (SLS), 70 parts by weight of methylmethacrylate (MMA) and 25 parts by weight of butylacrylate (BA) were added to prepare a monomer pre- To prepare a monomer pre-emulsion. When the internal temperature of the reactor reached 40 ° C., the monomer pre-emulsion, 0.001 part by weight of initiator tert-butyl hydroperoxide (TBHP) and 0.020 part by weight of sodium formaldehyde sulfoxylate (SFS) were administered at once to proceed the reaction.

2) Second polymerization step

0.05 part of a crosslinking agent (TMPTA) and 5 parts of methyl methacrylate (MMA) were introduced at a conversion rate of 90% after the initiation of the first stage acrylic copolymer and 0.003 part by weight of an initiator (tert-butyl hydroperoxide: TBHP) , And 0.03 part by weight of sodium formaldehyde sulfoxylate (SFS) were added thereto, and the reaction was allowed to proceed for 3 hours. The prepared acrylic copolymer latex TSC is about 35%, and the latex particle diameter is 160 nm.

3) Latex coagulation step

The nano-particle latex was diluted to 15% based on the solid content with respect to the prepared acrylic copolymer latex and the temperature of the mixed latex was raised to 75 ° C. 6 wt% of MgSO ₄ solution (10 wt%) was added thereto at a time to coagulate to obtain a slurry. The slurry was washed with ion-exchanged water 2 to 3 times to wash the by-products, After removing a large amount of washing water through filtration, a powdered sample was obtained by drying at 80 ° C. for 3 hours using a small fluidized bed dryer used for laboratory use.

< Example  2>

And 0.1 part by weight of a cross-linking agent (TMPTA) was used in the second polymerization step.

< Example  3>

Except that 80 parts by weight of methyl methacrylate (MMA) and 15 parts by weight of butyl acrylate (BA) were used in the first polymerization step.

< Example  4>

And 0.07 part by weight of a cross-linking agent (TMPTA) was used in the second polymerization step.

< Example  5>

And 0.1 part by weight of a cross-linking agent (TMPTA) was used in the second polymerization step.

< Comparative Example  1>

Except that 45 parts by weight of methyl methacrylate (MMA) and 50 parts by weight of butyl acrylate (BA) were used in the first polymerization step.

< Comparative Example  2>

Was prepared in the same manner as in Example 1, except that the crosslinking agent (TMPTA) was not added in the second polymerization step.

< Comparative Example  3>

And 0.01 part by weight of a cross-linking agent (TMPTA) was used in the second polymerization step.

< Comparative Example  4>

Was prepared in the same manner as in Example 3, except that the crosslinking agent (TMPTA) was not added in the second polymerization step.

< Comparative Example  5>

And 0.5 part by weight of a cross-linking agent (TMPTA) was used in the second polymerization step.

< Comparative Example  6>

Except that 90 parts by weight of methyl methacrylate (MMA) and 5 parts by weight of butyl acrylate (BA) were used in the first polymerization step.

The compositions of the acrylic type processing aids of Examples 1 to 5 and Comparative Examples 1 to 6 are summarized in Table 1 below. The weight average molecular weight (Mw) was determined by gel permeation chromatography (GPC) after dissolving in 0.25% THF of the prepared powdery sample.

Example Comparative Example One 2 3 4 5 One 2 3 4 5 6 One
step MMA 70 70 80 80 80 45 70 70 80 80 90 BA 25 25 15 15 15 50 25 25 15 15 5 1st Mw
(× 10,000, g / mol) 480 490 490 480 490 450 470 480 490 480 480 2
step MMA 5 5 5 5 5 5 5 5 5 5 5 TMPTA 0.05 0.1 0.05 0.07 0.1 0.1 - 0.01 - 0.5 0.1 final Mw
(× 10,000, g / mol) 1300 1400 1400 1500 1500 1300 700 850 750 880 1400 Reference
1) MMA: methyl methacrylate
2) BA: butyl acrylate
3) TMPTA: trimethylolpropane triacrylate

Referring to Table 1, the weight average molecular weight of the copolymer prepared through the first polymerization step ranged from 4.5 million to 4.49 million g / mol, and the weight average of the crosslinked copolymer after the second polymerization step The molecular weight ranged from 7 million g / mol to 15 million g / mol. Especially, in Examples 1 to 5 and Comparative Examples 1 and 5, it was confirmed that an ultrahigh molecular weight acrylic type processing aid was prepared through a secondary polymerization step.

Experimental Example  1: Preparation of vinyl chloride resin composition

After mixing the acrylic processing aid and vinyl chloride resin prepared in the above Examples and Comparative Examples, a specimen was prepared through foaming.

5.0 g of composite stabilizer KD-105 (monolithic industry, composite heat stabilizer obtained by uniformly mixing heat stabilizer and lubricant), 7 g of filler (CaCO ₃ ), ₂ g of TiO ₂ , wax After adding 0.2 g of mold lubricant AC316A, 5 g of the acrylic processing composition prepared in Examples 1 to 5 and Comparative Examples 1 to 6 and 0.8 g of azodicarbonamide as a foaming agent were added thereto, and 110 g of 110 And the mixture was stirred at the same temperature, thereby preparing a vinyl chloride resin composition containing an acrylic copolymer.

(1) Evaluation of foaming proportion

The vinyl chloride resin composition prepared above was extruded using a Haake twin extruder at a cylinder temperature of 180 ° C. and a screw speed of 30 rpm for 1 minute in a slit die size of 2 mm (thickness) × 30 mm (width) And the length was cut to 30 mm, and the density of the foams was measured using a plastic specific gravity measuring machine. In this case, the higher the specific gravity of the foam, the lower the expansion ratio, which means that the foam characteristics are insufficient. The results are shown in Table 2 below.

(2) Cell uniformity evaluation

The cross section of the foamed molded article obtained above was observed with an optical microscope to evaluate the cell uniformity by 5 points when the foam cells were uniform, 3 points when the foam cells were slightly uneven, and 1 point when the foam cells were not uniform The results are shown in Table 2 below.

(3) Evaluation of surface characteristics

The surface state of the sample produced by the foamed physical properties was observed to be 5 points when there was no die mark, no flow mark, uniform thickness, 3 points when there was little uniformity, And when the thickness was not uniform at all, it was evaluated by a five-point method. The results are shown in Table 2 below.

Example Comparative Example One 2 3 4 5 One 2 3 4 5 6 Foaming Specific Gravity (g / cm ³ )
[0.4 to 0.5] 0.44 0.45 0.45 0.43 0.42 0.52 0.57 0.51 0.57 0.58 0.48 Cell uniformity (5-point method)
[4-5] 5 5 5 5 5 3 One 4 One One 5 Surface properties (5-point method)
[4-5] 5 5 4 4 4 5 5 5 4 2 2

Referring to Table 2, the copolymer prepared through the two-step process according to the present invention satisfied the ultrahigh molecular weight and showed excellent results in the foam specific gravity, cell uniformity, and surface characteristics of the final molded product .

In contrast, in Comparative Examples 1 and 6, the weight average molecular weight of the final acrylic copolymer exceeded 10 million g / mol, which satisfied the ultrahigh molecular weight range of the present invention. However, methyl methacrylate (MMA) and butyl The content of acrylate (BA) monomer is out of the range defined in the present invention, and as a result, the specific gravity of foam and the cell uniformity are found to be defective.

On the other hand, Comparative Examples 2 to 5 were at a level that did not reach the ultra high molecular weight range. Specifically, in Comparative Example 2 and Comparative Example 4, since the crosslinking agent was not added in the secondary polymerization step, the foamed specific gravity and cell uniformity were poor. In Comparative Example 3, the amount of crosslinking agent was small and the specific gravity of the foamed foam was poor. 5 showed that the amount of crosslinking agent was excessive and the foam specific gravity, cell uniformity, and surface characteristics were poor due to gel formation.

Therefore, as shown in the results of the above Experimental Examples, the ultrahigh molecular weight acrylic-based processing aid according to the present invention improves the surface properties by decreasing the specific gravity of foam and increasing the cell uniformity during foam molding of the vinyl chloride resin, And it was confirmed that foam formability can be increased.

INDUSTRIAL APPLICABILITY The acrylic processing aid of the present invention can be used as a processing aid in the production of various molded articles using a vinyl chloride resin, thereby making it possible to produce molded articles having excellent physical properties.

Claims (12)

A copolymer obtained by crosslinking a methyl methacrylate monomer with a crosslinking agent to a copolymer of methyl methacrylate monomer and C1 to C18 alkyl acrylate monomer,
Wherein the crosslinked copolymer is copolymerized with 70 to 90% by weight of methyl methacrylate and 10 to 30% by weight of C1 to C18 alkyl acrylate within a total weight of 100% by weight of the monomer, and has a weight average molecular weight of 10 million g / mol. &lt; / RTI &gt;
The method according to claim 1,
Wherein the crosslinked copolymer has a weight average molecular weight of 10 to 30 million g / mol.
The method according to claim 1,
The C1 to C18 alkyl acrylate is one selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, and combinations thereof Ultra high molecular weight acrylic type processing aid.
The method according to claim 1,
Wherein the cross-linking agent is used in an amount of 0.05 to 1 part by weight based on 100 parts by weight of the total weight of monomers.
The method according to claim 1,
Examples of the crosslinking agent include 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, allyl acrylate, allyl methacrylate, Characterized in that it is at least one member selected from the group consisting of trimethylolpropane triacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, ethylene glycol dimethacrylate and divinylbenzene. .
A first polymerization step of copolymerizing 60 to 89% by weight of methyl methacrylate monomer and 10 to 30% by weight of C1 to C18 alkyl acrylate monomer within 100% by weight of the total weight of monomers; And
A second polymerization step of adding 1 to 10% by weight of methyl methacrylate monomer to the copolymer and 0.05 to 1 part by weight of a crosslinking agent based on 100 parts by weight of the total weight of the monomer to prepare a crosslinked copolymer and,
Wherein the crosslinked copolymer has a weight average molecular weight of 10 million g / mol or more.
The method according to claim 6,
Wherein after the first polymerization step, the copolymer has a weight average molecular weight of 3,000 to 8,000,000 g / mol.
The method according to claim 6,
Wherein the second polymerization step and the post-crosslinked copolymer have a weight average molecular weight of 10 million to 30 million g / mol.
The method according to claim 6,
The C1 to C18 alkyl acrylate is one selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, and combinations thereof By weight based on the total weight of the acrylic copolymer.
The method according to claim 6,
Examples of the crosslinking agent include 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, allyl acrylate, allyl methacrylate, Characterized in that it is at least one member selected from the group consisting of trimethylolpropane triacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, ethylene glycol dimethacrylate and divinylbenzene. &Lt; / RTI &gt;
The method according to claim 6,
In the secondary polymerization step, the addition of the crosslinking agent and methyl methacrylate is carried out at a time when the polymerization conversion ratio in the first polymerization step is 70 to 90%.
With respect to 100 parts by weight of the vinyl chloride resin,
A vinyl chloride resin composition comprising 0.1 to 30 parts by weight of an ultrahigh molecular weight acrylic type processing aid according to any one of claims 1 to 5.