KR102006725B1 - Acrylic processing aid and vinyl chloride resin composition comprising the same - Google Patents

Abstract

The present invention relates to an acrylic processing aid and a vinyl chloride-based resin composition comprising the same, and more particularly, a monomer having a specific composition is added to a core and a shell when preparing an acrylic processing aid having a core-shell structure, and having different specific viscosity. The present invention relates to an acryl-based processing aid and a vinyl chloride-based resin composition including the same, which can simultaneously play a role of a lubricant and a processing aid.

Description

Acrylic processing aid and vinyl chloride resin composition comprising the same

The present invention relates to an acryl-based processing aid and a vinyl chloride-based resin composition comprising the same, which can simultaneously perform the roles of a lubricant and a processing aid.

Vinyl chloride-based resins are homopolymers of vinyl chloride or hybrid polymers comprising at least 50% vinyl chloride. The vinyl chloride resin is used for various types of processing methods such as foam molding, extrusion molding, injection molding, calendering, and the like to wires, electric machine products, toys, films, sheets, artificial leather, tarpaulins, tapes, food packaging materials, and medical supplies. Widely used as a material for various products.

The vinyl chloride-based resin is excellent in hardness and tensile strength, in addition to the addition of various additives, for example, plasticizers, stabilizers, fillers, pigments and the like to give a variety of physical properties and functions can further expand the application field.

In addition to the addition method of the additive, it is possible to expand the application field of the vinyl chloride-based resin through a change in the processing process. For example, when the vinyl chloride-based resin is molded through foam molding, weight reduction of the molded article may be achieved and process cost may be reduced. However, when foaming with a vinyl chloride resin only during foam molding, sufficient stretching and melt strength cannot be obtained, resulting in poor appearance of the molded article, large foam cells, and a low foaming ratio. In order to solve this problem, a method of adding a processing aid to a vinyl chloride resin by mixing with a blowing agent has been widely studied.

As a typical processing aid, a method of adding a high molecular weight acrylate processing aid mainly containing methyl methacrylate to a vinyl chloride resin by mixing with a blowing agent has been developed.

For example, US Patent No. 6,391,976 discloses a technique of using an acrylate monomer as a comonomer in methyl methacrylate, and US Patent No. 6,221,966 discloses a latex polymerized using an alkyl acrylate as a main monomer. A technique for preparing methyl methacrylate by polymerization is proposed.

However, the higher the molecular weight of the acrylic processing aid, the lower the processability and dispersibility of the processing aid due to the higher viscosity, resulting in surface defects such as die marks, flow marks, fisheye (or undispersed melt projections) on the surface of the final molded product. Or, there is a problem that the difference in specific gravity according to the molded part is greatly increased.

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

Accordingly, the present inventors have conducted various researches to solve the above problems. As a result, the present inventors designed the core composition to enable the function of the lubricant, and designed the shell composition to enable the function of the processing aid to produce an acrylic processing aid and to produce it. When applied to the resin it was confirmed that it is possible to improve the foamability and moldability at the same time while preventing the adhesiveness while increasing the slip properties of the lubricant.

Accordingly, an object of the present invention is to provide an acrylic processing aid that can simultaneously perform the functions of a lubricant and a processing aid during foaming of vinyl chloride resin.

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

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

In order to achieve the above object, the present invention includes an acrylic latex of the core-shell structure,

The core comprises an aromatic monomer, a C2-C18 alkyl acrylate monomer and a vinyl-terminated polydimethylsiloxane copolymer;

The shell is grafted with the core to provide an acrylic processing aid comprising methyl methacrylate, C2 to C18 alkyl acrylate monomers and neopentyl glycol alkoxylate diacrylate copolymer.

In this case, the core has a specific viscosity (η _sp ) of 0.5 to 2.0, and the shell has a specific viscosity of 2 to 8.

In addition, the present invention comprises the steps of preparing a core through copolymerization comprising an aromatic monomer and an alkyl acrylate monomer of C2 to C18 and a vinyl terminal polydimethylsiloxane, and

Provided is a method for preparing an acrylic processing aid for preparing a shell by carrying out graft polymerization by adding methyl methacrylate, C2 to C18 alkyl acrylate monomer and neopentyl glycol alkoxylate diacrylate to the core.

The present invention also provides a vinyl chloride resin composition comprising the acrylic processing aid.

The acrylic processing aid according to the present invention is added to the production of a molded article of vinyl chloride resin through foam molding by simultaneously performing the functions of a lubricant and a processing aid to control the amount of extrusion in the processing process and to improve the surface properties of the final molded product. It lowers adhesiveness and raises workability while reducing protrusion generation.

In addition, as the foaming processability is increased, a cell is formed with a uniform specific gravity throughout the molded article, thereby making it possible to manufacture a high-quality vinyl chloride resin molded article.

Foam molding is carried out by putting a vinyl chloride resin and an acrylic processing aid in the mold and then using a blowing agent or applying pressure. The processing aid serves to promote the gelling of the vinyl chloride-based resin and to improve moldability and processability, and to improve the foaming ratio and stability of the foaming cell in foaming.

In the present invention, to prepare a core-shell structured acrylic processing aid, the core, and the shell is prepared by copolymerizing a monomer of a specific composition, by adjusting the specific viscosity (η _sp ) of each of the core and shell It serves as a processing aid without significantly increasing the molecular weight and at the same time obtains the effect obtained through the use of a conventional lubricant.

The lubricant is added during the molding process of the vinyl chloride-based resin to prevent lubrication and sticking (adhesion) of the metal surface in contact with the resin, and is used to increase fluidity. The use of these lubricants lowers the processing temperature, shortens the processing time and at the same time serves to improve the surface properties of the molded article.

In order to secure the above-described processing aids and lubricants and functions at the same time, in the present invention to prepare a processing aid of the core-shell structure, the core is copolymerized with a vinyl terminal polydimethylsiloxane copolymerized so as to perform the role of the lubricant In addition, the shell is characterized in that it comprises a copolymer copolymerized neopentyl glycol alkoxylate diacrylate so as to serve as a processing aid.

Specifically, the vinyl-terminated polydimethylsiloxane added to the core improves workability during processing with vinyl chloride-based resins, lowers tackiness, and improves slip properties of the resin, thereby resulting in die marks generated on the surface of the final molded product. In order to solve the problem of surface defects such as a flow mark and a fish eye or an undispersed molten protrusion, it functions as a lubricant. In addition, neopentyl glycol alkoxylate diacrylate is added to the shell not only to promote melting during processing with vinyl chloride-based resin, but also to control the specific gravity of foam and increase the cell uniformity, thereby serving as a processing aid. .

Hereinafter, each composition constituting the processing aid of the core-shell structure according to the present invention will be described in more detail.

Specifically, the core comprises a copolymer copolymerized with an aromatic monomer, an alkyl acrylate monomer of C2 to C18 and a vinyl terminal polydimethylsiloxane.

The aromatic monomer may be one selected from the group consisting of styrene, alpha methyl styrene, isopropenyl naphthalene, vinyl naphthalene, styrene substituted with C1 to C3 alkyl group, styrene substituted with halogen, and combinations thereof.

Such aromatic monomers are used in an amount of 30 to 70% by weight, preferably 40 to 65% by weight within 100% by weight of the total monomers forming the core. If the content is out of the above range, there is a problem that the workability and formability of the vinyl chloride-based resin is lowered through deterioration of the overall physical properties.

The alkyl acrylate of C2 to C18 may be one selected from the group consisting of ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, and a combination thereof, preferably butyl acrylate. Can be. At this time, the monomers represented by the alkyl acrylate of C2 to C18 may be used as the same monomer or different monomers in the core and shell production.

The alkyl acrylate monomers of C2 to C18 are used in 20 to 65% by weight, preferably 26 to 50% by weight within 100% by weight of the total monomers forming the core. If the content is out of the above range, there is a problem that the workability and formability of the vinyl chloride-based resin is lowered through deterioration of the overall physical properties.

In particular, the core of the acrylic processing aid presented in the present invention includes a vinyl-terminated polydimethylsiloxane represented by the following formula (1).

(In the formula 1,

and n is an integer of 1 to 100.)

When the vinyl-terminated polydimethylsiloxane of Chemical Formula 1 is added, the melt viscosity of the vinyl chloride-based resin is lowered to increase molding processability, to prevent adhesion between the mold and the resin used during molding, and to be slippery (sliding from side to side). ), Playing a role known as a glidant function. In addition, the surface properties of the finally obtained molded article of the vinyl chloride-based resin are improved to reduce surface defects such as die marks, flow marks, fisheye, and the like generated in the molded article. In addition, it is possible to mold to have a specific specific gravity throughout the molded article by increasing the mixing properties of the entire vinyl chloride-based resin.

To secure this effect, the vinyl terminated polydimethylsiloxane controls the molecular weight and its content.

Preferably, the vinyl-terminated polydimethylsiloxane may have a weight average molecular weight of 200 to 250,000 g / mol, and preferably 500 to 50,000 g / mol to perform the function as the above-mentioned lubricant. . In addition, the content is used in an amount of 0.01 to 10% by weight, preferably 0.05 to 3% by weight within 100% by weight of the total monomers forming the core. If the above molecular weight and content are outside these ranges, they cannot perform their function as lubricants, resulting in a problem that the processability and surface properties of the vinyl chloride-based resin are degraded through deterioration of the overall physical properties. Use it.

In addition, the shell of the acrylic processing aid according to the present invention is to provide a function as a processing aid, that is, excellent foaming properties, and includes methyl methacrylate and C2 to C18 alkyl acrylate monomer, in particular neopentyl glycol alkoxylate Copolymers copolymerized using diacrylates together.

Neopentyl glycol alkoxylate diacrylate is represented by Formula 2:

(In the formula (2)

R ₁ and R ₂ are the same as or different from each other, and each is a C1 to C4 alkylene group, and p + q is 2 to 5).

Preferably, the neopentyl glycol alkoxylate diacrylate may be neopentyl glycol ethoxylate diacrylate, neopentyl glycol propoxylate diacrylate, or neopentyl glycol butoxylate diacrylate, preferably Neopentyl glycol propoxylate diacrylate is used.

These neopentyl glycol alkoxylate diacrylates have double bonds at both ends and are grafted with the core to form a shell. In addition, it accelerates the melting of the vinyl chloride-based resin to shorten the processing time, and serves to improve the melt flowability and increase the extrusion amount. The shell is formed through copolymerization with other monomers, thereby improving the function as a processing aid, that is, processability and controlling the specific gravity of foaming, and simultaneously forming cells formed in the molded article.

Preferably, neopentyl glycol alkoxylate diacrylate may use a weight average molecular weight of 200 to 10,000 g / mol, preferably 250 to 8,000 g / mol to perform the function as the processing aid mentioned above I use that. In addition, the content is used in an amount of 0.01 to 10% by weight, preferably 0.5 to 7.0% by weight within 100% by weight of the total monomers forming the shell. If the above molecular weight and content are outside these ranges, they cannot perform their functions as processing aids, resulting in a problem that the processability, formability and foaming properties of the vinyl chloride-based resin are lowered due to lowering of the overall physical properties. Use appropriately selected to satisfy.

The composition of the other monomers for preparing the shell together with the neopentyl glycol alkoxylate diacrylate comprises 45 to 90% by weight of methyl methacrylate, 1 to 50% by weight of alkyl acrylate monomers of C2 to C18. The alkyl acrylate then follows what is mentioned in the core.

If the content of the methyl methacrylate and alkyl acrylate is out of the above range, there is a problem that the workability and formability of the vinyl chloride-based resin is lowered through the overall decrease in physical properties. If the methyl methacrylate content is out of the above range, there is a problem in that the processability and formability of the vinyl chloride-based resin are lowered through the reduction of the overall physical properties. In addition, when the content of the alkyl acrylate of C2 to C18 is less than the above range, it is difficult to expect the effect of shortening the expected melt time through the use of processing aids and reducing the amount of migrating gelate, on the contrary, when the content exceeds the above range, the melt pressure May reduce the workability, increase the specific gravity of the foam and decrease the cell uniformity, thereby lowering the foam formability.

On the other hand, the acrylic-based processing aid of the core-shell structure according to the present invention allows each core and the shell to have a specific specific viscosity with the limitation of the composition. In this case, the specific viscosity of the core and the shell refers to the specific viscosity of the copolymer constituting the core and the shell, respectively.

Specific viscosity (η _sp ) is one of the expressions of the viscosity of a polymer.In order to measure the viscosity of a polymer in a solution state, the outflow time (t) of the polymer solution is subtracted from the outflow time (t ₀ ) of the pure solvent. The value is the value divided by the outflow time (t ₀ ) of the pure solvent.

[Equation 1]

(In Equation 1, t is the outflow time of the polymer solution, t ₀ means the outflow time of the pure solvent.)

In this case, the high viscosity means that the outflow time is long, and the molecular weight of the polymer is high. On the contrary, the low viscosity means that the outflow time is short, and the molecular weight of the polymer is low.

In the present invention, the core may be manufactured to have a specific viscosity in the range of 0.5 to 2, preferably 1.2 to 1.8, to secure a function as a lubricant, that is, workability and surface properties. If out of the range, there is a problem that the workability is lowered, and a defect occurs in the surface properties of the final molded article, so that it is used to adjust to have the above range.

In addition, the shell is manufactured to have a specific viscosity in the range of 2 to 8, preferably 3.0 to 6.0, so as to improve the function as a processing aid, ie processability, formability and foaming properties. If it is out of the range, the control of the foaming specific gravity is not easy and the amount of extrusion is reduced to secure the above-described effect.

In addition, the acrylic processing aid of the co-shell structure according to the present invention is to include 5 to 50% by weight of the core and 50 to 95% by weight of the shell relative to the total 100% by weight of the monomer of the core and the shell. This range is a range for enabling the functions of the above-described effects required in each of the core and the shell, that is, the functions of the lubricant and the processing aid at the same time.

Acrylic latex having a core-shell structure as described above can be prepared through a two-step polymerization.

Specifically, the acrylic processing aid is prepared by mixing the aromatic monomer, C2 to C18 alkyl acrylate and vinyl-terminated polydimethylsiloxane as a monomer, followed by polymerization to prepare a core; And

Methyl methacrylate, C2 to C18 alkyl acrylate and neopentyl glycol alkoxylate diacrylate are mixed and polymerized as the core and monomer to prepare an acrylic processing aid having a core-shell structure.

Each step will be described below.

First, an aromatic monomer, alkyl acrylate of C2 to C18 and vinyl terminal polydimethylsiloxane are mixed, and then a core is prepared through emulsion polymerization.

Various compositions and reaction conditions required for emulsion polymerization are not particularly limited in the present invention, and are known in the art.

As an initiator, a water-soluble initiator is possible, For example, inorganic peroxides, such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, hydrogen peroxide; Potassium peroxide, t-butyl peroxide, cumene hydro peroxide, p-mentanehydro peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide Organic peroxides such as dibenzoyl peroxide, 3,5,5-trimethylhexanol peroxide and t-butyl peroxy isobutylate; Nitrogen compounds such as azobis isobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, azobisisobutyric acid (butyl acid) methyl and the like. These initiators are used in an amount of 0.03 to 0.2 parts by weight based on 100 parts by weight of the total monomers.

The polymerization may be capable of polymerization for 2 to 12 hours at 40 to 80 ℃.

According to an embodiment of the present invention, the emulsion polymerization may further include additives such as redox catalysts, polymerization initiators, emulsifiers (or surfactants), molecular weight regulators, activators, and ionized water which are commonly known in the art.

The molecular weight modifier is not particularly limited but includes, for example, a-methylstyrene dimer; mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan and octyl mercaptan; Halogenated hydrocarbons such as carbon tetrachloride, methylene chloride and methylene bromide; Sulfur-containing compounds such as tetraethyl thiuram disulfide, dipentamethylene thiuram disulfide, diisopropylquixanthogen disulfide, and the like, and may be used in an amount of 0.1 to 3 parts by weight based on 100 parts by weight of the monomer mixture.

The activator is not limited thereto, but at least one selected from sodium hydrosulfite, sodium formaldehyde sulfoxylate, sodium ethylenediamine tetraacetate, ferrous sulfate, lactose, dextrose, sodium linoleate and sodium sulfate in each step The total amount may be added in the range of 0.01 to 0.15 parts by weight based on 100 parts by weight in total.

The redox catalyst is not particularly limited, but may be, for example, sodium formaldehyde sulfoxylate, ferrous sulfate, disodium ethylenediaminetetraacetate, copper disulphate, and the like, based on 100 parts by weight of 0.01 to 0.1 parts by weight of the monomer mixture. It can be used in parts by weight.

Next, the core and the methyl methacrylate, C2 to C18 alkyl acrylate and neopentyl glycol alkoxylate diacrylate is added to prepare the shell, and then emulsion polymerized to prepare an acrylic latex having a core-shell structure.

In this case, the emulsion polymerization for preparing the shell is performed in the same manner as described above.

In addition, the acrylic processing aid may be agglomerated using a conventional acid, salt or polymer flocculant, and then dehydrated and dried to obtain a powder to be used in the foam molding process of the vinyl chloride resin.

These acrylic processing aids are used as processing aids in the foam molding of vinyl chloride resins and simultaneously perform functions as lubricants and processing aids to improve the surface defects of the final molded product, to form foam cells uniformly, and to form the entire molded product. It allows for the production of products with uniform specific gravity throughout.

Specifically, the acrylic processing aid according to the present invention is added to 0.1 to 30 parts by weight based on 100 parts by weight of the vinyl chloride resin to produce a variety of molded products through foam molding.

When the content of the acrylic processing aid is less than the above range, the processability, formability and thermal stability due to the use of the processing aid are low, and thus the quality of the manufactured molded article is lowered. And as the chemical properties are rather reduced, it is suitably used within the above range.

In this case, if necessary, it may further include various additives commonly used in the art. The additives include heat stabilizers, lubricants, impact modifiers, plasticizers, UV stabilizers, flame retardants, colorants, antibacterial agents, mold release agents, antioxidants, light stabilizers, compatibilizers, dyes, inorganic additives, surfactants, nucleating agents, coupling agents, fillers, admixtures Ordinary additives such as stabilizers, antistatic agents, pigments, flame retardants and the like may be added, these may be applied alone or mixed two or more kinds.

Foam molding using the vinyl chloride-based resin composition is not particularly limited in the present invention and follows a known method.

The molded article through foam molding improves the foaming ratio and the stability of the foaming cell during foaming to obtain a low specific gravity foam of 0.4 to 0.5 g / cm 3, and has a uniform foaming cell.

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: Manufacture of acrylic processing aid

(Step 1) Core Manufacturing

First, prepare a reactor of a four-necked flask equipped with a stirrer, a thermometer, a nitrogen inlet, and a circulating condenser, 100 parts by weight of deionized water (DDI water), 0.002 parts by weight of ferrous sulfate, and disodium ethylenediaminetetra. 0.04 parts by weight of acetate (Disodium ethylenediaminetetraacetate) was added and the temperature inside the reactor was maintained at 70 ° C. under a nitrogen atmosphere.

In order to prepare a monomer pre-emulsion, 70 parts by weight of ionized water, 0.50 parts by weight of sodium dodecylbenzene sulfonate (SDBS), 25 parts by weight of styrene (SM), 14.6 parts by weight of butylacrylate (BA), Vinyl A monomer preemulsion was prepared by adding 0.4 parts by weight of terminated Polydimethylsiloxane (Vinyl-t-PDMS, Mw: 1000 g / mol). When the temperature inside the reactor reached 70 ° C, 0.02 parts by weight of potassium peroxide (KPS) and 0.020 parts by weight of sodium formaldehyde sulfoxylate (SFS) were used as a monomer preemulsion and an initiator for 3 hours. I was. The obtained core latex had a total solid content (TSC) of about 35% and a latex particle size of 130 nm.

(Step 2) Production of acrylic processing aid

0.25 parts by weight of the emulsifier SDBS, 48 parts by weight of methyl methacrylate (MMA), 11.4 parts by weight of BA, neopentyl glycol propoxylate diacrylate (NGPD, Mw: 320 g) / mol) 0.6 parts by weight into the reactor at a temporary temperature and when the temperature inside the reactor reaches 45 ℃ 0.008 parts by weight of tert-Butyl hydroperoxide (TBHP) initiator and 0.03 parts by weight of sodium formaldehyde sulfoxylate (SFS) The reaction was allowed to proceed for 3 hours.

The latex thus obtained had a solid content (TSC) of about 40% and a latex particle size of 155 nm.

After the latex was diluted 15% based on the solid content and the mixed latex temperature was raised to 70 ° C., 4 parts by weight of calcium chloride solution (10% by weight) was added at once to agglomerate to obtain a slurry. After washing the by-products through two to three washes with exchange water, and then removing a large amount of the wash water through filtration, a small fluidized-bed dryer used for laboratory use is used. To dry for 3 hours at 80 ℃ to prepare a core-shell acrylic processing aid in the form of a powder.

Example  2

In the same manner as in Example 1, except that 48 parts by weight of methyl methacrylate, 10.8 parts by weight of butyl acrylate, and 1.2 parts by weight of neopentyl glycol propoxylate diacrylate (NGPD) were used to prepare the shell in the second step. An acrylic processing aid was prepared.

Example  3

An acrylic processing aid was prepared in the same manner as in Example 1, except that 25 parts by weight of styrene, 14.2 parts by weight of butyl acrylate, and 0.8 parts by weight of vinyl-terminated polydimethylsiloxane were used in the core polymerization in one step.

Example  4

An acrylic processing aid was prepared in the same manner as in Example 1, except that the polymerization temperature was 40 ° C. in the two-step shell polymerization, and 0.004 parts by weight of the initiator (TBHP) was used.

Example  5

An acrylic processing aid was prepared in the same manner as in Example 1, except that the polymerization temperature was 80 ° C. in the first step, and 0.08 parts by weight of the initiator (KPS) was used.

Example  6

An acrylic processing aid was prepared in the same manner as in Example 1 except that the polymerization temperature was 83 ° C. and the initiator (KPS) was used at 0.30 part by weight.

Example  7

An acrylic processing aid was prepared in the same manner as in Example 1, except that the polymerization temperature was 70 ° C. and the initiator (TBHP) was used in an amount of 0.20 parts by weight.

Example  8

An acrylic processing aid was prepared in the same manner as in Example 1, except that 25 parts by weight of styrene, 10.0 parts by weight of butyl acrylate, and 5.0 parts by weight of V-PDMS were used during the first stage core polymerization.

Comparative Example  One

An acrylic processing aid was prepared in the same manner as in Example 1, except that 25 parts by weight of styrene and 15.0 parts by weight of butyl acrylate were used during the core polymerization in one step.

Comparative Example  2

An acrylic processing aid was prepared in the same manner as in Example 1, except that 48 parts by weight of methyl methacrylate and 12.0 parts by weight of butyl acrylate were used in the shell polymerization in two steps.

Experimental Example  One

The specific viscosity of the acrylic processing aids prepared in Examples and Comparative Examples was measured and shown in Table 1 below, wherein the content of each composition was shown.

The specific viscosity was calculated by dissolving 0.5 g of the powdery sample of each latex in 10 ml of THF solvent using the Ubbelohde viscometer based on Equation 1 above.

In Table 1, SM is styrene, BA is butyl acrylate, V-PDMS is vinyl-terminated polydimethylsiloxane (Mw: 1000 g / mol), and NGPD is neopentyl glycol propoxylate diacrylate (Mw: 320 g / mol).

Composition (parts by weight) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 Stage 1 SM 25 25 25 25 25 25 25 25 25 25 BA 14.6 14.6 14.2 14.6 14.6 14.6 14.6 10 15 14.6 V-PDMS 0.4 0.4 0.8 0.4 0.4 0.4 0.4 5 0 0.4 Non-viscosity
(0.5 to 2.0) 1.5 1.6 1.4 1.5 0.8 0.2 1.4 1.6 1.5 1.5 Step 2 MMA 48 48 48 48 48 48 48 48 48 48 BA 11.4 10.8 11.4 11.4 11.4 11.4 11.4 11.4 11.4 12 NGPD 0.6 1.2 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0 Non-viscosity
(2.0 to 8.0) 4.5 4.6 4.4 5.5 4.6 4.3 1.7 4.7 4.5 4.5

Experimental Example  2

(One) Vinyl chloride resin  Produce

Specimens were prepared through foaming after mixing the acrylic processing aid and the vinyl chloride-based resin prepared in Examples and Comparative Examples.

100 g of vinyl chloride-based resin (LS080, manufactured by LG Chemical) 5.0 g of composite stabilizer KD-105 (composite heat stabilizer mixed uniformly with heat stabilizer and lubricant), 7 g of filler (CaCO ₃ ), ₂ g of TiO ₂ , wax After adding 0.2 g of the type lubricant AC316A, 5 g of each acrylic processing aid prepared in Examples and Comparative Examples and 0.8 g of azodicarbonamide blowing agent were added and kneaded while heating up to 110 ° C. using a Henschel mixer ( Mixing) to prepare a vinyl chloride-based resin composition comprising an acrylic copolymer.

(2) property measurement

(2-1) Foam processing property analysis

The vinyl chloride resin composition prepared in Experimental Example (1) was slit die size 2 mm (thickness) x 30 mm (width) at a cylinder temperature of 180 ° C. and a screw speed of 30 rpm using a Haake twin extruder. ), And the extrusion amount was measured, and the melt pressure value was also measured.

The foaming density was measured using a plastic specific gravity measuring instrument by cutting into a length of 30 mm. At this time, the higher the foaming density, the lower the foaming magnification, and the lower the foaming characteristics. In addition, the cross section of the foamed molded article obtained above was observed by an optical microscope, and the cell uniformity was set at 5 points when the foamed cell was uniform, 3 points when the foamed cell was slightly uneven, and 1 point when most of the foamed cells were not uniform. Sex was evaluated.

(2-2) surface properties

The surface state of the sample prepared in the foam processing properties was observed and evaluated by a 5-point evaluation method. There are no die marks or flow marks at all, and the thickness is equal to five points. Three points are used when the die marks and flow marks are slightly generated and the thickness is not uniform. One point is the die marks and flow. It was judged that the mark was severe and the thickness was not uniform at all.

(2-3) Fisheye (fish eye, Unbalanced Melt  Turning) measurement

After preparing the vinyl chloride-based resin composition without adding a filler in the preparation of the vinyl chloride-based resin composition, using a 20 mm single screw extruder equipped with a T-die, a cylinder temperature of 180 ° C and a screw of 30 rpm After extracting a 0.2mm thick film from the speed, observe the number of fisheyes within the defined area of the film surface visually. 5 points if there is almost no fisheye, 3 points if fisheye is slightly generated, and fisheye When a lot is produced, it was evaluated as one point.

(2-4) adhesive evaluation

100 g of polyvinyl chloride (polymerization rate = 800, LG Chem LS080), 3.0 g of Tin-based stabilizer, and 0.9 g of calcium stearate (Ca-St) were added to a Henschel Mixer at room temperature for tackiness evaluation. The mixture was kneaded while heating up to 115 ° C. at rpm, and cooled to 40 ° C. to complete the master batch. After adding 3 g of the sample and kneading again at room temperature, 100 g of the powder mixture was processed using a 6 inch 2-roll mill for 4 minutes under a roll kneading temperature of 200 ° C., a roll rotation speed of 14 × 15 rpm, and a roll interval of 0.3 mm. ), And the adhesion on the roll surface was evaluated. The evaluation used the 5-point method and evaluated based on the following criteria.

5: There is no elongation as it peels.

4: There is almost no extension as it peels.

3: slightly peeled off.

2: It peels off but increases a lot.

1: No peeling off.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 Extrusion amount
(g / min) 62 66 63 64 65 63 63 63 61 56 Foam specific gravity
(g / cm ³⁾ 0.44 0.43 0.45 0.42 0.46 0.46 0.53 0.46 0.48 0.52 Cell uniformity 5 5 4 5 5 5 2 4 4 3 Surface properties 4 4 5 4 5 One 4 2 2 4 Fisheye 4 5 4 5 4 2 4 One 2 5 Stickiness 5 4 5 5 4 One 3 One One 4 <Proper property range>
Extrusion amount (g / min) [60 to 70] Foam specific gravity (g / cm ³ ) [0.4 to 0.5]
Cell uniformity (5-point method) [4-5] Surface characteristics (5-point method) [4-5]
Protrusion (5-point method) [4-5] Adhesiveness (5-point method) [4-5]

Referring to Table 2, in the case of the vinyl chloride-based resin composition using the acrylic processing aid proposed in the present invention, satisfactory values can be obtained in all extrusion properties, foam specific gravity, cell uniformity, surface properties, protrusions and adhesive properties. there was.

In contrast, in the case of the molded article of Comparative Example 1, marks or the like occurred on the surface of the molded article due to the non-use of V-PDMS in the core, fisheye (undispersed molten protrusion) occurred, and the adhesiveness was poor. .

In addition, in the case of the molded article of Comparative Example 2, due to the non-use of NGPD on the shell side, the surface characteristics, protrusions and tackiness of the molded article was good, but poor performance in terms of foam specific gravity and cell uniformity due to insufficient performance as a processing aid. Indicated.

In addition, it can be seen that even when copolymerizing with the same composition as in the composition of the core and shell, the specific viscosity of the copolymer constituting the core and shell affects various aspects such as workability, surface properties, and foaming properties.

 Specifically, the molded article of Example 6 and Example 7, including the same composition as in Example 1 but different in specific viscosity of the core and the shell, respectively. In the case of the molded article of Example 6, as including the core having a lower specific viscosity compared to the core of Example 1 showed a tendency that the surface properties and adhesive properties are reduced. In addition, in the case of the molded article of Example 7, including a shell having a low specific viscosity, the foam specific gravity is increased compared to the molded article of Example 1, the cell uniformity tended to decrease.

In addition, in the case of Example 8, when the content of the V-PDMS in the core is used excessively, the surface properties of the manufactured molded article is lowered, not only protruding but also poor adhesion.

From these results, it can be seen that in order to simultaneously perform the functions of the lubricating agent and the processing aid, not only the limitation of the composition of each core and shell, but also the control of their respective viscosity are very important.

The acrylic processing aid of the present invention can be used as a processing aid in the production of various molded products using vinyl chloride-based resins to enable the production of molded articles having excellent physical properties.

Claims (14)

A core-shell structured acrylic latex,
The core comprises an aromatic monomer, a C2-C18 alkyl acrylate monomer and a vinyl-terminated polydimethylsiloxane copolymer;
The shell is grafted with the core, the acrylic processing aid comprising methyl methacrylate, C2 to C18 alkyl acrylate monomer and neopentyl glycol alkoxylate diacrylate copolymer. The method of claim 1, wherein
Specific viscosity (η _sp ) of the core is 0.5 to 2.0,
Acrylic processing aid of the specific viscosity of the shell 2 to 8. The method of claim 1,
Within 100% by weight of the total monomers forming the core, an acrylic system comprising 30 to 70% by weight of aromatic monomers, 20 to 65% by weight of alkyl acrylate monomers of C2 to C18 and 0.01 to 10% by weight of vinyl-terminated polydimethylsiloxane. Processing aids. The method of claim 1,
The aromatic monomer includes styrene, alphamethyl styrene, isopropenyl naphthalene, vinyl naphthalene, styrene substituted with C1 to C3 alkyl group, halogen substituted styrene, and combinations thereof. Acrylic processing aid. The method of claim 1,
The alkyl acrylate of C2 to C18 is an acrylic processing aid comprising one selected from the group consisting of ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate and combinations thereof. The method of claim 1,
The vinyl terminal polydimethylsiloxane is an acrylic processing aid represented by Formula 1:
[Chemical Formula 1]

(In Formula 1,
and n is an integer of 1 to 100.) The method of claim 1,
The vinyl terminal polydimethylsiloxane is an acrylic processing aid having a weight average molecular weight of 200 to 250,000 g / mol. The method of claim 1,
Within 100% by weight of the total monomers forming the shell, 45 to 90% by weight of methyl methacrylate and 1 to 50% by weight of alkyl acrylate monomers of C2 to C18 and 0.01 to 10% by weight of neopentyl glycol alkoxylate diacrylate Acrylic processing aid containing%. The method of claim 1,
The neopentyl glycol alkoxylate diacrylate is an acrylic processing aid represented by Formula 2 below:
(2)

(In the formula (2)
R ₁ and R ₂ are the same as or different from each other, and each is a C1 to C4 alkylene group, and p + q is 2 to 5). The method of claim 1,
The neopentyl glycol alkoxylate diacrylate is at least one selected from neopentyl glycol ethoxylate diacrylate, neopentyl glycol propoxylate diacrylate and neopentyl glycol butoxylate diacrylate. The method of claim 1,
The neopentyl glycol alkoxylate diacrylate has a weight average molecular weight of 200 to 10,000 g / mol acrylic processing aid. The method of claim 1,
The acrylic processing aid comprises 5 to 50% by weight of the core and 50 to 95% by weight of the shell relative to the total 100% by weight of the monomers of the core and the shell. Preparing a core through copolymerization comprising an aromatic monomer, a C2-C18 alkyl acrylate monomer and a vinyl terminated polydimethylsiloxane, and
Method for preparing an acrylic processing aid comprising the step of preparing a shell by performing a graft polymerization by adding methyl methacrylate, C2 to C18 alkyl acrylate monomer and neopentyl glycol alkoxylate diacrylate to the core. A vinyl chloride resin composition comprising the acrylic processing aid according to any one of claims 1 to 12.