WO2014133254A1

WO2014133254A1 - Pvc foam processing aid, method for manufacturing same, and polyvinyl chloride resin composition comprising same

Info

Publication number: WO2014133254A1
Application number: PCT/KR2013/011817
Authority: WO
Inventors: 김윤호; 김건수; 이광진
Original assignee: (주) 엘지화학
Priority date: 2013-02-28
Filing date: 2013-12-18
Publication date: 2014-09-04

Abstract

This description relates to a polyvinyl chloride (PVC) foam processing aid, a method for manufacturing the same, and an obtained polyvinyl chloride resin composition comprising the same. The present invention provides a PVC foam processing aid, and a polyvinyl chloride resin composition therefrom which has excellent cohesion properties and reinforces the foam formability of PVC.

Description

PPC foaming aid, preparation method thereof and vinyl chloride resin composition comprising the same

The present disclosure relates to a PVC foam processing aid, a manufacturing method, and a vinyl chloride resin composition. More specifically, the present invention relates to a PVC foam processing aid, which is excellent in agglomeration properties and reinforces the foam moldability of a vinyl chloride resin (Polyvinylchloride, PVC). A method and a vinyl chloride resin composition.

Vinyl chloride resin (PVC) is a polymer containing 50% or more vinyl chloride. It is widely used in various fields because it is inexpensive, easy to control hardness, can be applied to most processing equipment, and has a good physical / chemical property. Is used.

However, these vinyl chloride resins are poor in impact strength, processability, thermal stability, heat deformation temperature, and additives have been developed to compensate for them. For example, impact modifiers, processing aids, stabilizers, fillers and the like are appropriately selected depending on the application.

In recent years, interest in foam molding is increasing as a means for reducing the weight of vinyl chloride resin and lowering the cost of molded products. For reference, if the vinyl chloride resin is foamed alone, sufficient stretching and melt strength cannot be obtained, and thus the appearance of the molded article is poor, and the foaming cell is large and uneven, so that the foaming ratio is low.

Therefore, a method of adding a high molecular weight acrylate processing aid mainly composed of methyl methacrylate with a blowing agent to add to the vinyl chloride resin has been developed to compensate for this.

As a specific example, US Pat. No. 6,391,976 discloses a technique of using an acrylate monomer as a comonomer in methyl methacrylate, while US Pat. No. 6,221,966 discloses methyl in latex polymerized using alkyl acrylate as a main monomer. Techniques for polymerizing methacrylates have been proposed.

On the other hand, the high molecular weight styrene-acrylonitrile-based copolymer has a competitive advantage in terms of cost than the high molecular weight acrylate-based processing aid described above, but exhibits a deterioration in quality during foaming of vinyl chloride resin.

Accordingly, the present disclosure aims to provide a PVC foam processing aid and a method for producing the same using a high molecular weight styrene-acrylonitrile copolymer and capable of exhibiting foaming properties equivalent to those of a molecular weight acrylate processing aid.

It is another object of the present invention to provide a vinyl chloride resin composition reinforced with foam moldability using the PVC foam processing aid.

According to this description,

50 to 90 wt% of a styrene-acrylonitrile copolymer; And 50 to 10 wt% of alkyl methacrylate and alkyl acrylate copolymers;

The styrene-acrylonitrile copolymer has a weight average molecular weight (Mw) in the range of 2,000,000 to 5,000,000 g / mol, and the alkyl methacrylate and alkyl acrylate copolymers have a weight average molecular weight (Mw) of 200,000 to It provides a PVC foam processing aid, characterized in that in the range of 1,000,000g / mol.

In addition, according to the present description,

A first step of polymerizing a styrene monomer and an acrylonitrile monomer under a polymerization initiator to obtain a styrene-acrylonitrile copolymer having a weight average molecular weight (Mw) of 2,000,000 to 5,000,000 g / mol; And

7.5 to 40 wt% of an alkyl methacrylate monomer and 2.5 to 10 wt% of an alkyl acrylate monomer are added to 50 to 90 wt% of the first stage copolymer and polymerized under a polymerization initiator to obtain a weight average molecular weight (Mw) of 200,000 to 1,000,000 g. It provides a method for producing a PVC foam processing aid consisting of; a second step of obtaining a polymer having a structure surrounding the first step copolymer is an alkyl methacrylate and alkyl acrylate copolymer of / mol.

Furthermore, according to the present description,

Provided is a vinyl chloride resin composition comprising a vinyl chloride resin and the above-mentioned PVC foam processing aid.

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

The present substrate has a technical feature to provide a PVC foam processing aid as a PVC foam processing aid excellent in cohesive properties and capable of reinforcing the foam moldability of a vinyl chloride resin.

Specifically, the PVC foam processing aid may comprise a styrene-acrylonitrile-based copolymer and an alkyl methacrylate-based and alkyl acrylate-based copolymer, for example, styrene-acrylonitrile-based copolymer 50 ~ Consisting of 90wt% and 50-10wt% of alkyl methacrylate and alkyl acrylate copolymers not only improves the cohesive properties but also increases the cell size due to uneven foaming during foaming. The foaming moldability of the vinyl chloride resin, which has been degraded, can also be reinforced, which is preferable.

As a specific example, the styrene-acrylonitrile-based copolymer may be composed of 60 to 85 wt% and 15 to 40 wt% of the alkyl methacrylate and alkyl acrylate copolymers.

For example, the styrene-acrylonitrile-based copolymer has a weight average molecular weight (Mw) of 2,000,000 to 5,000,000 g / mol, 2,000,000 to 4,000,000 g / mol, 3,000,000 to 4,000,000 g / mol, or 3,200,000 to 3,500,000 g to improve foaming characteristics. It may be / mol.

For example, the alkyl methacrylate and alkyl acrylate copolymers have a weight average molecular weight (Mw) of 200,000 to 1,000,000 g / mol, 300,000 to 850,000 g / mol, or 500,000 to 700,000 g so as to improve foaming and flocculating properties. / mol.

In addition, the styrene-acrylonitrile-based copolymer is included in the 50 to 90wt% of the total content of the PVC foam processing aid to improve the cohesive properties as well as to reinforce the foam moldability of the vinyl chloride resin. As a specific example, the styrene-acrylonitrile-based copolymer may be included in 60 to 85wt% of the total content of the PVC foam processing aid.

In the present description, the styrene-acrylonitrile-based copolymer may include acrylonitrile-based monomers within a range of 13 to 28 wt% or 18 to 22.5 wt% based on the total weight of all monomers constituting the PVC foaming aid. It is preferable in terms of securing. For example, the acrylonitrile-based monomer may be at least one selected from the group consisting of acrylonitrile, methacrylonitrile, fumaronitrile, α-chloronitrile, and α-cyano ethyl acrylonitrile.

In addition, the styrene-based monomers used in the styrene-acrylonitrile-based copolymer is 38 to 66wt% or 42 to 59.5wt% based on the total weight of the total monomers constituting the PVC foaming processing aid foam foamability It can be reinforced appropriately.

The styrene monomer may be at least one selected from the group consisting of styrene, α-methyl styrene, t-butyl styrene, chloro styrene, and p-methyl styrene.

As another example, the styrene-acrylonitrile-based copolymer, the alkyl methacrylate monomer, in the range of 0.01 to 28wt%, or 0.1 to 15wt% based on the total weight of all monomers constituting the PVC foam processing aid. It may further include.

The alkyl methacrylate monomers are, for example, methyl methacrylate, n-butyl methacrylate, lauryl methacrylate, stearyl methacrylate, tridecyl methacrylate, i-butyl methacrylate, t-butyl It may be at least one selected from the group consisting of methacrylate, 2-ethylhexyl methacrylate and cyclohexyl methacrylate.

As a specific example, the styrene monomer and the acrylonitrile monomer may be included in a weight ratio of 50 to 80:50 to 20. That is, the styrene-acrylonitrile copolymer may include 50 to 80 wt% of styrene monomer and 20 to 50 wt% of acrylonitrile monomer based on a total of 100 wt%.

As another example, the styrene-acrylonitrile-based copolymer is 50 to 70wt% of styrene monomer, 15 to 25wt% of acrylonitrile monomer and alkyl methacrylate based on 100% by weight of the total monomers constituting the copolymer. It may be to include 15 to 25wt% monomer.

As another example, the styrene-acrylonitrile-based copolymer is 50 to 70wt% of styrene monomer, 15 to 25wt% of acrylonitrile monomer and alkyl methacrylate based on 100% by weight of the total monomers constituting the copolymer. It includes 15 to 25wt% monomer, it may be included in the range of 0.01 to 30 parts by weight of the comonomer based on 100 parts by weight of the copolymer. The comonomer is not limited as long as it is a type commonly used in the art.

The alkyl methacrylate-based and alkyl acrylate-based copolymers added to the styrene-acrylonitrile-based copolymer may serve to provide processing aids having excellent coagulation characteristics through glass transition temperature control depending on the amount used. have. As a specific example, the alkyl acrylate monomers, It is appropriate to include within the range of 2.5 ~ 10wt%, or 3 ~ 8wt% based on the total weight of the total monomers constituting the PVC foam processing aid can be aggregated in the normal powder particle size distribution.

For example, the alkyl methacrylate-based and alkyl acrylate-based copolymers include 60 to 90 wt% of alkyl methacrylate-based monomers and alkyl acrylate-based monomers based on a total of 100 wt% of the alkyl methacrylate-based and alkyl acrylate-based copolymers. It may be to include a monomer 10 ~ 40wt%.

As another example, the alkyl methacrylate-based and alkyl acrylate-based copolymers are 60 to 90 wt% of alkyl methacrylate-based monomers and alkyl acrylates based on a total of 100 wt% of the alkyl methacrylate-based and alkyl acrylate-based copolymers. System monomer It may be to include 10 to 30wt% and comonomer 0.01 to 30wt%. The comonomer is not limited as long as it is a type commonly used in the art.

As another example, the alkyl methacrylate-based and alkyl acrylate-based copolymer may be a copolymer having a structure surrounding the styrene-acrylonitrile-based copolymer.

In addition, the alkyl methacrylate monomers used in the alkyl methacrylate-based and alkyl acrylate-based copolymers include, for example, within the range of 7.5 to 40 wt% or 12 to 32 wt% based on the total weight of all monomers constituting the processing aid. Can sufficiently improve the flocculating properties.

The alkyl methacrylate monomer may be at least one selected from the types described in the description of the styrene-acrylonitrile copolymer, for example.

The alkyl acrylate monomer is selected from the group consisting of methyl acrylate, ethyl acrylate, n-butyl acrylate, lauryl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate, for example. It may be one or more.

If necessary, it may be one containing 0.01 to 10wt% comonomer. The comonomer is not limited as long as it is a type commonly used in the art.

The polymerization method used in the present description is not specified as long as it is a normal polymerization method such as emulsion polymerization, suspension polymerization, or solution polymerization.

As a specific example, a first step of polymerizing a styrene monomer and an acrylonitrile monomer under a polymerization initiator to obtain a styrene-acrylonitrile copolymer having a weight average molecular weight (Mw) of 2,000,000 to 5,000,000 g / mol; And

7.5 to 40 wt% of an alkyl methacrylate monomer and 2.5 to 10 wt% of an alkyl acrylate monomer are added to 50 to 90 wt% of the first stage copolymer and polymerized under a polymerization initiator to obtain a weight average molecular weight (Mw) of 200,000 to 1,000,000 g. The second step of obtaining a polymer having a structure surrounding the first step copolymer is an alkyl methacrylate and alkyl acrylate-based copolymer of / mol.

The first step may be polymerized by further comprising 0.001 ~ 28wt% of the alkyl methacrylate monomers, based on the total weight of the total monomers constituting the PVC foam processing aid.

That is, the styrene-acrylonitrile-based copolymer includes 50 to 70 wt% of styrene monomer, 15 to 25 wt% of acrylonitrile monomer, and 15 to 25 wt% of alkyl methacrylate monomer based on a total of 100 wt%. Can be.

In the second step, the alkyl methacrylate monomer and the alkyl acrylate monomer may be added in a total amount of 59 to 6 wt% to 41 to 94 wt% of the first step product.

In each polymerization, initiators such as known organic peroxides, inorganic peroxides, and nitrogen oxides can be used. Examples thereof include t-butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide and succinic acid per. Oil peroxide, organic peroxides such as peroxymaleic acid t-butyl ester, cumene hydroperoxide, benzoyl peroxide, inorganic peroxides such as potassium persulfate, sodium persulfate, or oil-soluble initiators such as azobis isobutyronitrile. .

In addition, the initiator may be sodium sulfite, sodium thiornate, sodium metabisulfite, sodium bisulfite, sodium dithionite, sodium 2-hydroxy-2-sulfinatoacetic acid, ascorbic acid, hydroxyacetone, or sulfuric acid. It may be a redox type initiator type obtained by combining ferrous and a reducing agent of an EDTA complex.

The polymerization initiator may be added in 0.003 to 0.3 parts by weight, 0.004 to 0.1 parts by weight, or 0.004 to 0.007 parts by weight based on 100 parts by weight of the total monomers constituting the PVC foam processing aid.

Among these, well-known surfactants can be used for emulsion polymerization, For example, anionic surfactants, such as sodium alkyl sulfonate, sodium alkylbenzene sulfonate, sodium dioctyl sulfonate, sodium lauryl sulfate, sodium fatty acid, or alkyl phenols, aliphatic It may be at least one selected from nonionic surfactants such as alcohols, propylene oxide and reaction products with ethylene oxide.

Furthermore, one or more types selected from conventional additives such as antioxidants, ultraviolet absorbers, and ultraviolet stabilizers can be combined as necessary.

For example, the polymerization of the first step and the second step may be performed at 3.5 to 5.5 hr, or 3.5 to 5 hr at 30 to 55 ° C. or 35 to 45 ° C., respectively.

The second step product may be aggregated to obtain a powder. Here, the aggregation temperature may be, for example, 58 ~ 97 ℃ or 66 ~ 80 ℃.

The powder thus obtained may be blended with a vinyl chloride resin to enhance foam moldability to provide a composition. As another example, the powder obtained by 100 parts by weight of the vinyl chloride resin may be blended in the range of 1 to 20 parts by weight, or 1 to 10 parts by weight.

According to the present invention, it is excellent in the flocculation characteristics, and provides a PVC foam processing aid and a vinyl chloride resin composition comprising the same that effectively reinforces the foam formability and the flocculation characteristics of vinyl chloride resin (Polyvinylchloride, PVC).

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the examples.

실시예 1~5 및 비교예 1~4Examples 1-5 and Comparative Examples 1-4

〔실시예 1〕EXAMPLE 1

160 parts by weight of deionized water, 0.8 parts by weight of an emulsifier (KAO, Latemul ASK), 0.01 parts by weight of ethylenediamine tetrasodium acetate, and 0.001 parts by weight of ferrous sulfate were added to a 5L polymerization reactor equipped with a stirrer, and then the inside of the reactor was purged with nitrogen gas. Substitution was carried out sufficiently and the temperature was heated up at 40 degreeC.

Then, 52.5 parts by weight of styrene and 22.5 parts by weight of acrylonitrile were added, 0.05 part by weight of sodium formaldehyde sulfoxy acid and 0.005 part by weight of tert-butyl hydroperoxide were polymerized for 6 hours, and the average particle size was 120 nm. Copolymer latex was obtained (polymer conversion: 96%, Mw of one step copolymer: 3,500,000 g / mol).

In this case, the average particle diameter corresponds to a value measured using a submicron particle sizer manufactured by PSS (Particle Sizing Systems), NICOMP 380.

0.2 parts by weight of an emulsifier (KAO, Latemul ASK), 0.002 parts by weight of ethylenediaminetetrasodium acetate, 0.0002 parts by weight of ferrous sulfate were added to the reactor in two stages, and then 20 parts by weight of methyl methacrylate as a two-stage monomer and butyl 5 parts by weight of acrylate was added, 0.01 parts by weight of sodium formaldehyde sulfoxy acid and 0.005 parts by weight of tertiary butyl hydroperoxide were added and polymerized at 40 ° C. for 4 hours to prepare a two-step copolymer latex having an average particle diameter of 140 nm. Obtained (polymer conversion: 98%, Mw of the two stage copolymer: 600,000 g / mol).

The latex obtained was aggregated with calcium chloride, washed with water and dried to obtain powder.

〔실시예 2〕EXAMPLE 2

In Example 1, the same process as in Example 1 was repeated except that 17 parts by weight of methyl methacrylate and 8 parts by weight of butyl acrylate were added as two-stage monomers. At this time, the Mw of the two-stage copolymer was 600,000 g / mol.

〔실시예 3〕EXAMPLE 3

In Example 1, Example 1 except that 59.5 parts by weight of styrene and 25.5 parts by weight of acrylonitrile were added as a first-stage monomer and 12 parts by weight of methyl methacrylate and 3 parts by weight of butyl acrylate as a second-stage monomer. The same process was repeated.

At this time, the Mw of the first stage copolymer was 3,500,000 g / mol, and the Mw of the two stage copolymer was 500,000 g / mol.

〔실시예 4〕EXAMPLE 4

Except that in Example 1, 42 parts by weight of styrene, 18 parts by weight of acrylonitrile were added as a first step monomer, and 32 parts by weight of methyl methacrylate and 8 parts by weight of butyl acrylate were added as a second step monomer. The same process as in Example 1 was repeated.

At this time, the Mw of the first stage copolymer was 3,500,000 g / mol, and the Mw of the second stage copolymer was 700,000 g / mol.

〔실시예 5〕[Example 5]

In Example 1, the same process as in Example 1 was repeated except that 42 parts by weight of styrene, 18 parts by weight of acrylonitrile, and 15 parts by weight of methyl methacrylate were added as monomers.

At this time, the Mw of the first stage copolymer was 3,200,000 g / mol, and the Mw of the second stage copolymer was 500,000 g / mol.

〔비교예 1〕[Comparative Example 1]

In Example 1, 70 parts by weight of styrene and 30 parts by weight of acrylonitrile were added as the first step monomer, and the first step copolymer latex obtained without the second step polymerization was aggregated with calcium chloride, washed with water and dried to obtain a powder.

At this time, the Mw of the first stage copolymer was 3,500,000 g / mol.

〔비교예 2〕[Comparative Example 2]

In Example 1, 80 parts by weight of methyl methacrylate and 20 parts by weight of butyl acrylate were added as one-step monomers, and the one-step copolymer latex obtained without two-step polymerization was aggregated with calcium chloride, washed with water and dried to obtain powder. Obtained.

At this time, the Mw of the first stage copolymer was 700,000 g / mol.

〔비교예 3〕 (Comparative Example 3)

In Example 1, the same process as in Example 1 was repeated except that 0.04 parts by weight of tertiary butyl hydroperoxide as an initiator was added and polymerization was performed at 60 ° C. for 3 hours.

At this time, the Mw of the two-stage copolymer was 100,000 g / mol.

〔비교예 4〕(Comparative Example 4)

The same process as in Example 1 was repeated except that 0.01 parts by weight of tertiary butyl hydroperoxide as an initiator was added in Example 1 and polymerization was performed at 60 ° C. for 4 hours.

At this time, the Mw of the first stage copolymer was 1,800,000 g / mol, and the Mw of the second stage copolymer was 700,000 g / mol.

〔비교예 5〕(Comparative Example 5)

In Example 1, the same process as in Example 1 was repeated except that 0.002 parts by weight of tertiary butyl hydroperoxide as an initiator was added and polymerization was performed at 35 ° C. for 6 hours.

At this time, the Mw of the two-stage copolymer was 1,200,000 g / mol.

4 parts by weight of the polymer powder obtained in Examples 1 to 5 and Comparative Examples 1 to 5, 100 parts by weight of a vinyl chloride resin (LG080, manufactured by LG Chemical), 4 parts by weight of a thermal stabilizer (OTL-9, precurable), calcium carbonate 7 parts by weight, 2 parts by weight of lubricant, 2 parts by weight of TiO ₂ , 0.7 parts by weight of blowing agent (azodicarbonamide) were mixed using a Henschel mixer at elevated temperature up to 115 ° C., and fitted with a rectulular slit die. Foaming was carried out using a Haake twin extruder to prepare test specimens 5 mm thick and 30 mm wide.

Then, the property values measured according to the following test items are shown in Table 1 below.

〈시험 항목〉<Test Items>

Aggregation temperature (℃) : After coagulation of the copolymer latex, the temperature of the content of the passing fraction was measured to 20% or less in a mesh having a mesh size of 200 (seive size 0.075mm) (when the aggregation temperature was too high or too low). Unable to prepare a powdery polymer of the appropriate size).

Torque in foam extrusion (%), melt pressure (bar), melting temperature (℃): Hakke foam extruder (extrusion temperature: C1 / C2 / A / D = 170/178/180/178 ℃, screw speed: Measured at 25 rpm).

Extrusion amount during foam extrusion (g / min): Mass of the molded product processed in the extruder in 1 minute during foam molding.

Foam specific gravity during foam extrusion (g / cc): Value measured using a specific gravity meter.

Foam cell size (mm) during foam extrusion: Average value of 50 cell sizes measured using an optical microscope.

Table 1

division	Flocculation temperature (℃)	Torque (%)	Melt Pressure (Bar)	Extrusion amount (g / min)	Foam specific gravity (g / cc)	Foam cell size (mm)
Example 1	71	79	124.2	68.3	0.427	101
Example 2	66	84	125.0	68.7	0.466	97
Example 3	80	80	121.8	67.7	0.489	91
Example 4	70	84	125.8	68.8	0.471	99
Example 5	72	87	135.7	68.5	0.409	111
Comparative Example 1	-	72	112	62.5	0.713	69
Comparative Example 2	64	70	104.7	66.1	0.719	62
Comparative Example 3	68	70	115.5	67.0	0.612	83
Comparative Example 4	69	76	114.0	64.0	0.580	74
Comparative Example 5	76	75	114.7	61.1	0.655	72

As shown in Table 1, in the case of Examples 1 to 5 it is easy to form the powder even at a temperature of 90 ℃ or less and promotes processing even during the foam extrusion process, high extrusion amount and good foaming properties to low foam specific gravity.

On the other hand, in the case of not having a two-step copolymer of the appropriate molecular weight as in Comparative Example 1 there is a problem that the foam specific gravity is high and the extrusion amount is low. In addition, the high Tg has a problem that the size of the powder is too small.

If the molecular weight of the first stage copolymer does not have a high molecular weight styrene and acrylonitrile copolymer as in Comparative Example 2, or if the molecular weight of the first stage copolymer is low as in Comparative Example 4, the foaming properties are deteriorated, and as shown in Comparative Examples 3 and 5, Even if the molecular weight is too high or low, there was a problem that the foaming characteristics deteriorate.

Further experiments were carried out in the same manner as in Example 1 to confirm the change in physical properties according to the monomer content and molecular weight change to be used and the results are summarized in Table 2 below.

〔비교예 6〕(Comparative Example 6)

In Example 1, Example 1 except that 66.5 parts by weight of styrene and 28.5 parts by weight of acrylonitrile were added as a first-stage monomer and 4 parts by weight of methyl methacrylate and 1 part by weight of butyl acrylate as a second-stage monomer. The same process was repeated.

At this time, the Mw of the first stage copolymer was 3.5 million g / mol, and the Mw of the second stage copolymer was 300,000 g / mol.

〔비교예 7〕(Comparative Example 7)

In Example 1, Example 1 except that 28 parts by weight of styrene and 12 parts by weight of acrylonitrile were added as the first step monomer, and 48 parts by weight of methyl methacrylate and 12 parts by weight of butyl acrylate were added as the second step monomer. The same process was repeated.

At this time, the Mw of the first stage copolymer was 3.5 million g / mol, and the Mw of the second stage copolymer was 900,000 g / mol.

〔비교예 8〕(Comparative Example 8)

In Example 1, the same process as in Example 1 was repeated except that 23 parts by weight of methyl methacrylate and 2 parts by weight of butyl acrylate were added as the second step monomer.

At this time, the Mw of the first stage copolymer was 3.5 million g / mol, and the Mw of the second stage copolymer was 500,000 g / mol.

〔비교예 9〕(Comparative Example 9)

In Example 1, the same process as in Example 1 was repeated except that 12.5 parts by weight of methyl methacrylate and 12.5 parts by weight of butyl acrylate were added as two-stage monomers.

At this time, the Mw of the first stage copolymer was 3.5 million g / mol, and the Mw of the second stage copolymer was 700,000 g / mol.

〔비교예 10〕(Comparative Example 10)

In Example 1, the same process as in Example 1 was repeated except that 67.5 parts by weight of styrene and 7.5 parts by weight of acrylonitrile were added as the first step monomer.

At this time, the Mw of the first stage copolymer was 3.7 million g / mol, and the Mw of the two stage copolymer was 600,000 g / mol.

〔비교예 11〕 Comparative Example 11

In Example 1, the same process as in Example 1 was repeated except that 37.5 parts by weight of styrene and 37.5 parts by weight of acrylonitrile were added as the first step monomer.

At this time, the Mw of the first stage copolymer was 2.5 million g / mol, and the Mw of the two stage copolymer was 600,000 g / mol.

TABLE 2

division	Coagulation Temperature (℃)	talk (%)	Melt Pressure (Bar)	Extrusion amount (g / min)	Foam specific gravity (g / cc)	Foam cell size (mm)
Comparative Example 6	98	76	113.8	62.3	0.627	77
Comparative Example 7	68	76	114.2	61.5	0.604	78
Comparative Example 8	-	79	120.7	66.0	0.487	95
Comparative Example 9	57	76	113.4	61.8	0.599	74
Comparative Example 10	72	72	107.1	61.2	0.724	66
Comparative Example 11	69	76	114.2	61.0	0.609	84

As shown in Table 2, when the content of the two-step copolymer is too low or high, as in Comparative Examples 6 and 7, there is a problem that the foam specific gravity is high and the extrusion amount is low. In addition, when the content of the two-stage copolymer is insufficient as in Comparative Example 6, when the content of the butyl acrylate in the two-stage monomer is low as in Comparative Example 8, the size of the powder is too small due to the high Tg.

In addition, when the content of the butyl acrylate is high in the two-stage monomer as in Comparative Example 9, there is a problem in that the aggregation is easy but the foaming properties are lowered.

Furthermore, as in Comparative Examples 10 and 11, even when the ratio of acrylonitrile in the one-stage copolymer is high or low, the foaming properties were lowered due to a decrease in compatibility with PVC.

Claims

50 to 90 wt% of a styrene-acrylonitrile copolymer; And 50 to 10 wt% of alkyl methacrylate and alkyl acrylate copolymers;

The styrene-acrylonitrile copolymer has a weight average molecular weight (Mw) in the range of 2,000,000 to 5,000,000 g / mol, and the alkyl methacrylate and alkyl acrylate copolymers have a weight average molecular weight (Mw) of 200,000 to PVC foam processing aid, characterized in that in the range of 1,000,000g / mol.
The method of claim 1,

The styrene-acrylonitrile-based copolymer is a PVC foam processing aid, characterized in that obtained by polymerization comprising a styrene-based monomer and acrylonitrile-based monomer in a weight ratio of 50 ~ 80:50 ~ 20.
The method of claim 1,

The styrene-acrylonitrile-based copolymer is obtained by polymerizing an alkyl methacrylate monomer to a styrene monomer and an acrylonitrile monomer.
The method of claim 3,

The styrene-acrylonitrile-based copolymer is based on 100 wt% of the monomers constituting the styrene-acrylonitrile-based copolymer, 50 to 70 wt% of styrene monomer, 15 to 25wt% of acrylonitrile monomer and alkyl methacrylate PVC foaming processing aid, characterized in that obtained by polymerization comprising a monomer of 15-25wt%.
The method of claim 1,

The alkyl methacrylate-based and alkyl acrylate-based copolymers include 60 to 90 wt% of alkyl methacrylate-based monomers and 10 to 10 alkyl acrylate-based monomers based on a total of 100 wt% of the alkyl methacrylate-based and alkyl acrylate-based copolymers. PVC foam processing aid comprising 40 wt% and obtained by polymerization.
The method of claim 5,

The alkyl acrylate monomer is one selected from the group consisting of methyl acrylate, ethyl acrylate, n-butyl acrylate, lauryl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate. PVC foam processing aid, characterized in that above.
The method according to claim 3 or 5,

The alkyl methacrylate monomers are methyl methacrylate, n-butyl methacrylate, lauryl methacrylate, stearyl methacrylate, tridecyl methacrylate, i-butyl methacrylate, t-butyl methacrylate PVC foam processing aid, characterized in that at least one selected from the group consisting of latex, 2-ethylhexyl methacrylate and cyclohexyl methacrylate.
The method according to any one of claims 2 to 4,

The styrene-based monomer is PVC foam processing aid, characterized in that at least one selected from the group consisting of styrene, α-methyl styrene, t-butyl styrene, chloro styrene, and p-methyl styrene.
The method according to any one of claims 2 to 4,

The acrylonitrile-based monomer is PVC foam processing aid, characterized in that at least one selected from the group consisting of acrylonitrile, methacrylonitrile, fumaronitrile, α-chloronitrile, and α-cyano ethyl acrylonitrile .
The method of claim 1,

The alkyl methacrylate and alkyl acrylate-based copolymer is a PVC foam processing aid, characterized in that the copolymer having a structure surrounding the styrene-acrylonitrile-based copolymer.
A first step of polymerizing a styrene monomer and an acrylonitrile monomer under a polymerization initiator to obtain a styrene-acrylonitrile copolymer having a weight average molecular weight (Mw) of 2,000,000 to 5,000,000 g / mol; And

In the 50-90 wt% of the first step copolymer, 7.5-40 wt% of the alkyl methacrylate monomer and 2.5-10 wt% of the alkyl acrylate monomer were added and polymerized under a polymerization initiator to obtain a weight average molecular weight (Mw) of 200,000-1,000,000 g. The second step of obtaining a polymer having a structure surrounding the first step copolymer is an alkyl methacrylate and alkyl acrylate-based copolymer of / mol;
The method of claim 11,

The first step is based on a total of 100% by weight of the styrene-acrylonitrile copolymer, 50 to 70wt% styrene monomer, 15 to 25wt% acrylonitrile monomer and 15 to 25wt% alkyl methacrylate monomer And a polymerization process for producing a PVC foam.
The method of claim 11,

The second step of the product is agglomerated to obtain a powder; The manufacturing method of the PVC foam processing aid further comprises a.
Vinyl chloride resin; And a PVC foam processing aid according to any one of claims 1 to 10.
The method of claim 14,

The composition is a vinyl chloride resin composition comprising 100 parts by weight of vinyl chloride resin and 1 to 20 parts by weight of PVC foam processing aid.