KR100523909B1 - Processing Aids for Vinyl Chloride Resin and Method for Preparing Thereof - Google Patents

Abstract

The present invention relates to a processing aid for vinyl chloride resin and a method for producing the same, wherein the processing aid of the present invention comprises at least one monomer selected from the group consisting of methyl methacrylate, acrylate, methacrylate, and mixtures thereof; It is composed of multifunctional monomers and is produced through two-step copolymer polymerization, which can shorten the melting time in processing vinyl chloride resin without affecting the intrinsic physical properties of vinyl chloride resin, and at the same time extrusion foaming There is an effect that can satisfy the excellent foaming ratio and the stability of the foaming cell in processing.

Description

Processing Aids for Vinyl Chloride Resin and Method for Preparing Thereof}

 The present invention relates to a processing aid for vinyl chloride resin and a method for manufacturing the same, and more particularly, it is possible to shorten the melting time in the processing of vinyl chloride resin without affecting the intrinsic physical properties of the vinyl chloride resin, and at the same time extrusion foaming The present invention relates to a processing aid for vinyl chloride resin and a method for producing the same, which can satisfy both the foaming ratio and the stability of the foaming cell in processing.

 Vinyl chloride resins are widely used in various fields because they provide molded articles having excellent physical and chemical properties. However, the vinyl chloride resin has various processing problems such as the processing temperature is close to the pyrolysis temperature, and the moldable temperature range is narrow, and the time to reach the molten state is long.

 In order to solve the above problems, a method of adding a plasticizer to a vinyl chloride resin, a method of using a vinyl chloride resin copolymerized with other monomers such as vinyl acetate, and a method of mixing other resin components with a vinyl chloride resin Etc. were known.

 However, none of the above techniques have been sufficiently improved in processability while maintaining excellent physical and chemical properties inherent in vinyl chloride resin. For example, when a plasticizer is added to a vinyl chloride resin or a vinyl chloride-based resin in which other monomers are copolymerized with vinyl chloride is used, there is a problem that the physical properties of the molded article are greatly changed.

 The method of mixing other resin components with the vinyl chloride resin mostly lowers the melt viscosity during molding, thereby lowering the processing temperature. Since kneading energy is consumed by the flow during processing, the gelation of vinyl chloride resin is insufficient, resulting in a problem of deterioration in physical properties compared to a sufficiently gelled vinyl chloride resin. There was a problem that does not have stability.

 Accordingly, U. S. Patent No. 6,221, 966 describes the glass transition temperature by controlling the size of the particle size in the overall two-stage polymerization and reducing the content of methyl methacrylate in the inner layer to improve the processability, transparency and foamability of the vinyl chloride resin. (Tg) was lowered, and the outer layer, on the contrary, discloses a method of making a copolymer by increasing the glass transition temperature. However, this method is effective for improving workability but not enough for improving foamability. In addition, European Patent No. 1,153,936 discloses a method for producing a high molecular weight copolymer using a copper (Cu) compound at the start of the reaction in the preparation of processing aids. However, the copolymer produced by the above method is not sufficient in the processing properties.

  U. S. Patent No. 6,140, 417 discloses a glass transition temperature (Tg) by a total three-stage polymerization comprising methyl methacrylate and one of alkyl acrylates or alkyl methacrylates and copolymerizable vinyl monomers for improved processability and foamability. After a low-controlled one-step polymerization, it discloses a method for preparing a processing aid consisting of a two-step polymerization, the glass transition temperature is adjusted higher than the first step, and a three-step polymerization, the glass transition temperature is lower than the two steps. The method is not satisfactory in processability and foamability. U. S. Patent No. 6,391, 976 discloses a process for preparing a processing aid of a two-stage copolymer with methyl methacrylate and a small amount of alkyl methacrylate having 3 to 5 carbon atoms, but is not satisfactory in processability and expansion ratio.

  Therefore, there is a need for further study on the processing aid of vinyl chloride resin having excellent processability and foaming characteristics in extrusion foaming processing of vinyl chloride resin, and a vinyl chloride resin composition containing the same.

  The present inventors studied the processing aid for thermoplastic resins in order to improve the foaming unevenness, the lack of foamability, etc., which occur in the process of melt delay and compression foaming processing, and polymerized in two stages using a small amount of polyfunctional monomer. As a result, it was confirmed that the molecular weight is high and the melt time during processing can be satisfied, and that the excellent foamability and the stability of the foaming cell can be simultaneously satisfied in the extrusion foaming process, thereby completing the present invention.

 In order to solve the above problems, the present invention can shorten the melting time in the processing of vinyl chloride resin without affecting the intrinsic physical properties of the vinyl chloride resin, and improve the foaming nonuniformity generated in the extrusion foaming process is excellent An object of the present invention is to provide a processing aid for vinyl chloride resin and a method for producing the same, which can satisfy both foaming properties and foam cell stability.

 Moreover, an object of this invention is to provide the vinyl chloride type resin composition which shows the outstanding foamability in extrusion foaming process, and which markedly improved the appearance stability and the stability of foaming cell.

The above and other objects of the present invention can be achieved by the present invention described below.

 The present invention to achieve the above object,

 60 to 86 parts by weight of methyl methacrylate; 14 to 39.9 parts by weight of one or more monomers selected from the group consisting of alkyl acrylates, alkyl methacrylates, and mixtures thereof; And 0.0001 to 0.1 parts by weight of at least one monomer selected from the group of multifunctional monomers.

       The alkyl acrylate is from the group consisting of methyl acrylate, ethyl acrylate, n-butyl acrylate, lauryl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate having 1 to 18 carbon atoms One or more may be selected.

      The alkyl methacrylate is n-butyl methacrylate, lauryl methacrylate, stearyl methacrylate, tridecyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl meta It may be selected from the group consisting of acrylate, and cyclohexyl methacrylate.

      The group of the multifunctional monomer is aryl methacrylate, 1,3-butylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol di It may consist of methacrylate.

The relative viscosity of the processing aid of the vinyl chloride resin may be η _rel 4.0 to 12.0.

      In addition, the present invention provides a group of 69.9 to 95% by weight of methyl methacrylate, 4 to 30% by weight of at least one monomer selected from the group consisting of alkyl acrylates, alkyl methacrylates, and mixtures thereof, and polyfunctional monomers. Step 1 to prepare a copolymer consisting of 0.0001 to 0.1% by weight of one or more monomers selected from; And from 29.45% by weight of at least one monomer selected from the group consisting of 54.9 to 70% by weight of methyl methacrylate, alkyl acrylate, alkyl methacrylate, and mixtures thereof in the presence of the copolymer made in step 1. And it provides a method for producing a processing aid of vinyl chloride resin comprising the two steps of preparing a copolymer consisting of 0.0001 to 0.1% by weight of at least one monomer selected from the group of multifunctional monomers.

       25 to 35 parts by weight of the copolymer prepared in step 1; And it can provide a method for producing a vinyl chloride resin processing aid, characterized in that for preparing a vinyl chloride resin processing aid comprising 65 to 75 parts by weight of the copolymer prepared in step 2.

      The present invention also provides a vinyl chloride resin composition comprising 0.1 to 20 parts by weight of the processing aid of the vinyl chloride resin and 100 parts by weight of polyvinyl chloride resin.

Hereinafter, the present invention will be described in detail.

The processing aid for the vinyl chloride resin of the present invention is a polypipe and 14 to 39.9 parts by weight of at least one monomer selected from the group consisting of 60 to 86 parts by weight of methyl methacrylate and alkyl acrylate, alkyl methacrylate, and mixtures thereof. A copolymer containing 0.001 to 0.1 parts by weight of a functional monomer has a relative viscosity η _rel 4.0 or more.

The copolymer having a relative viscosity of η _rel 4.0 or more used in the present invention is at least one monomer 14 selected from the group consisting of 60 to 86 parts by weight of methyl methacrylate, and alkyl acrylate, alkyl methacrylate, and mixtures thereof. To 39.9 parts by weight and 0.001 to 0.1 parts by weight of the multifunctional monomer are prepared in two steps.

The copolymer prepared by the emulsion polymerization of the two stages is preferably a relative viscosity η _rel 4.0 or more and 12.0 or less. When the relative viscosity η _rel 4.0 or less, the foamability and the stability of the foaming cell deteriorate at the same time, and when the relative viscosity η _rel 12.0 or more, the processing characteristics are lowered.

The methyl methacrylate is preferably included in the copolymer composition 60 to 86 parts by weight, more preferably 75 to 85 parts by weight. If the content is less than 60 parts by weight, there is a problem that the compatibility with the vinyl chloride composition during processing is lowered, the processability is worse. If the content is more than 86 parts by weight, the initial dispersibility is lowered during processing may cause foam non-uniformity. .

The at least one monomer selected from the group consisting of alkyl acrylates, alkyl methacrylates, and mixtures thereof is preferably included in the copolymer composition in an amount of 14 to 39.9 parts by weight, more preferably 15 to 25 parts by weight. Will be.

The multifunctional monomer is preferably included in the copolymer composition 0.0001 to 0.1 parts by weight, more preferably 0.001 to 0.05 parts by weight. If the content is less than 0.0001 parts by weight does not increase sufficiently in the molecular weight does not exert an effect on improving the foamability, when it exceeds 0.1 parts by weight, the processing efficiency is lowered due to the crosslinking of the copolymer and foaming processability is also slightly reduced.

The said alkyl acrylate is C1-C18 linear alkyl, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, lauryl acrylate, or stearyl acrylate, and C1-C4, such as 2-ethylhexyl acrylate C1-C18 cyclic alkyl, such as 18 branched alkyl or cyclohexyl acrylate, etc. can be used.

The alkyl methacrylate is n-butyl methacrylate, lauryl methacrylate, stearyl methacrylate, tridecyl methacrylate i-butyl methacrylate, t-butyl methacrylate, 2-ethylnuclear methacrylate Alkyl or C2-C18 alkyl, such as a cyclohexyl methacrylate, can be used.

The polyfunctional monomer may be used both in asymmetry and symmetry, and as the asymmetry, aryl methacrylate, 1,3-butylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, and the like may be used. Alternatively, as the symmetric polyfunctional monomer, divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, or the like may be used.

The copolymer can be prepared by the method of emulsion polymerization, suspension polymerization, solution polymerization, etc., in particular emulsion polymerization is most preferred. Of course, the polymer may be prepared using conventional emulsifiers, polymerization initiators, redox catalysts, and the like.

The copolymer of the present invention may be prepared using 0.3 to 2.5 parts by weight of an emulsifier, 0.0001 to 0.5 parts by weight of a polymerization initiator, 0.01 to 0.5 parts by weight of a redox catalyst, and the like.

The emulsifier is not particularly limited, but is not limited to aliphatic ester, alkyl benzene sulfonate, alkyl phosphate salt, dialkyl sulfosuccinate, potassium stearate salt Anionic emulsifiers such as (Potassium stearate), or nonionic emulsifiers such as polyoxyethylene alky ether and alkylamine esters may be used. The said emulsifier can be used individually or in mixture of 2 or more types.

The polymerization initiator is a water-soluble initiator such as potassium persulfate, ammonium persulfate, or sodium persulfate, t-butyl hydroperoxide, cumene hydroperoxide fat-soluble initiators such as organic peroxides such as cumene hydroperoxide, benzoyl poeroxide, lauryl peroxide, and the like, or redox initiators.

The redox catalyst is at least one combination from the group consisting of sodium formaldehyde sulfoxylate, disodium ethylenediaminetetraacetate, formaldehyde sodium sulfoxylate, ferrous sulfate, ferrous sulfate, ethylenesodium diaminetetraacetate, and the like. Redox catalysts can be used.

The processing aid is prepared in a latex state and then agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powder.

The processing aid of the present invention is added in an amount of 0.1 to 20 parts by weight to 100 parts by weight of the polyvinyl chloride resin to provide a vinyl chloride resin composition having excellent processing characteristics, and is also excellent for extrusion foam molding. When used for foam molding, it is possible to obtain a foamed molded article having a low specific gravity and a uniform foamed cell.

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.

Example 1

Copolymer preparation

90 parts by weight of ion-exchanged water, 1.6 parts by weight of potassium stearate solution as emulsifier, 25.995 parts by weight of methyl methacrylate, and butyl acrylate in a four-necked flask equipped with a stirrer, a thermometer, a nitrogen inlet, and a circulation condenser. By weight, 0.005 parts by weight of aryl methacrylate was added to make an emulsion. Subsequently, the internal temperature of the reactor was maintained at 45 ° C., replaced with a nitrogen atmosphere, and then 0.005 parts by weight of 10% aqueous solution of t-butyl hard peroxide and 0.02 parts by weight of 1% activator were added as a polymerization initiator. The first batch reaction was carried out.

After the reaction was completed, the mixture was stirred at a temperature of about 60 ° C. for about 1 hour, and the internal temperature of the reactor was reduced to 50 ° C. 58 parts by weight of ion-exchanged water, 0.5 parts by weight of potassium stearate solution as an emulsifier, 51.995 parts by weight of methyl methacrylate, 18 parts by weight of butyl acrylate, and polymerization with a mixture made of 0.005 parts by weight of aryl methacrylate. As an initiator, a secondary batch reaction was performed by adding 0.005 parts by weight of 10% aqueous solution of t-butyl hard peroxide and 0.03 parts by weight of 1% by weight of an activator.

 After the reaction was completed, the internal temperature of the reactor was increased to 70 ° C, and 0.01 part by weight of 10% aqueous solution of t-butyl hardroperoxide and 0.05 part by weight of 1% by weight of an activator were added as a polymerization initiator. The mixture was further stirred for about 1.5 hours. The activating solution used at this time consists of a redox catalyst, the composition of the activating solution used in the present embodiment is shown in Table 1.

Activation solution composition ingredient Content (parts by weight) Disodium ethylenediaminetetraacetate (EDTA) 0.0085 Formaldehyde sodium sulfoxylate (SFS) 0.04 Ferrous sulfate 0.001 Ion exchange water 4.9005

The relative viscosity of the powdery processing aid obtained by coagulation of the stirred latex with calcium chloride (CaCl ₂ ), dehydration and drying showed a value of η _rel 7.0.

Manufacture of vinyl chloride resin composition

 5 parts by weight of the processing aid was added to 100 parts by weight of vinyl chloride resin (LG Chem, LS080) having a degree of polymerization of 800, and mixed in a Henschel mixer to prepare a vinyl chloride resin composition.

Foam resin composition preparation

6.4 parts by weight of composite stabilizer KD-105 (composite thermal stabilizer and foam stabilizer with uniform mixture of thermal stabilizer and lubricant) in 100 parts by weight of vinyl chloride resin (LG Chem, LS080) having a degree of polymerization 800, CaCO ₃ as filler 14 parts by weight was added, and 4 parts by weight of the processing aid prepared above, 0.8 part by weight of azodicarboamide (azodicarbonamide) was added as an azo pyrolytic blowing agent, and mixed using a Henschel mixer to prepare a foamed resin composition.

Example 2

In the same conditions and the same composition as in Example 1, the copolymer was prepared by increasing the amount of aryl acrylate, which is a multifunctional monomer, to 0.01 parts by weight and 0.01 parts by weight in a one-step batch reaction and a two-step batch reaction, respectively. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 7.5.

Example 3

Copolymers were prepared by increasing the amount of aryl acrylate, which is a multifunctional monomer, by 0.05 parts by weight and 0.01 parts by weight, respectively, in the same conditions and the same composition as in Example 1 in the one-step batch reaction and the two-step batch reaction. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 8.7.

Example 4

Copolymers were prepared by increasing the amount of aryl acrylate, which is a multifunctional monomer, by 0.01 parts by weight and 0.05 parts by weight, respectively, under the same conditions and the same composition as Example 1 in the one-step batch reaction and the two-step batch reaction. After the reaction, the latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 9.6.

Comparative Example 1

Copolymers were prepared by increasing the amount of aryl acrylate, which is a multifunctional monomer, by 0.2 parts by weight and 0.2 parts by weight, respectively, under the same conditions and the same composition as Example 1 in the one-step batch reaction and the two-step batch reaction. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid.

Comparative Example 2

The copolymer was prepared by increasing the amount of aryl acrylate, which is a multifunctional monomer, by 0.5 parts by weight and 0.5 parts by weight, respectively, under the same conditions and the same composition as Example 1 in the one-step batch reaction and the two-step batch reaction. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid.

Comparative Example 3

The copolymer was prepared by reducing the amounts of aryl acrylate, which is a multifunctional monomer, by 0.0005 parts by weight and 0.0005 parts by weight, respectively, in the same conditions and the same composition as Example 1 in the one-step batch reaction and the two-step batch reaction. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a value of relative viscosity η _rel 3.9.

[Comparative Example 4]

Under the same conditions and the same composition as in Comparative Example 3, a copolymer was prepared by reacting a 2-functional batch reaction without adding aryl acrylate which is a multifunctional monomer. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a value of relative viscosity η _rel 3.6.

[Comparative Example 5]

The copolymer was prepared by reacting the same conditions and the same composition as in Comparative Example 3, without adding aryl acrylate which is a multifunctional monomer in a one-step batch reaction. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a value of relative viscosity η _rel 3.8.

Comparative Example 6

In Example 1, a copolymer was prepared by polymerizing without using the multifunctional monomer used in the one-step batch reaction and the two-step batch reaction. After the reaction, the latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 2.8.

Experimental Example 1

Physical properties were measured by the following method using the processing aids prepared in Examples 1 to 4 and Comparative Examples 1 to 6, and the results are shown in Table 3 below.

A) Relative Viscosity (η _rel )-A solution of 0.25 g of sample dissolved in 50 ml of tetrahydrofuran (THF) was measured using a Ubbelhode viscometer in a 30 ° C. thermostat.

 B) Melting time-60 g of the polyvinyl chloride composition was measured to a maximum load using a Haake rheometer at a temperature of 180 ° C. and 30 rpm.

 C) Foaming stability-Using a 30 mm single spindle extruder with a regular slit die, a 5 mm (thickness) x 30 mm (wide) rectangular rod was extracted at a cylinder temperature of 180 ° C and a screw speed of 30 rpm, and then cut out. The cross section was observed and evaluated according to the criteria in Table 2 below.

○ Foam cell is uniform △ Foam cell is slightly uneven × Most foam cells are not uniform

D) foamability-The specimens from the foam stability evaluation were cut to a certain size and then evaluated for specific gravity. At this time, the lower the specific gravity of the molded article, the higher the expansion ratio.

In Table 3, below. MMA is methyl methacrylate, BA is butyl acrylate, AMA is aryl methacrylate, BDMA is 1,3-butylene glycol dimethacrylate, BDAA is 1,3-butylene glycol diacrylate, DVB is di Vinylbenzene, EGDMA stands for ethylene glycol dimethacrylate, DEGDMA stands for diethylene glycol dimethacrylate

division Example Comparative example One 2 3 4 One 2 3 4 5 6 Copolymer Composition Stage 1 MMA 25.995 25.99 25.95 25.99 25.95 25.9 25.9995 25.9995 26 26 BA 4 4 4 4 4 4 4 4 4 4 AMA 0.005 0.01 0.05 0.01 0.2 0.5 0.0005 0.0005 ― ― Tier 2 MMA 51.995 51.99 51.99 51.95 51.95 51.9 51.9995 52 51.9995 52 BA 18 18 18 18 18 18 18 18 18 18 AMA 0.005 0.01 0.01 0.05 0.2 0.5 0.0005 ― 0.0005 ― Relative viscosity η _rel 7.0 7.5 8.7 9.6 Insoluble Insoluble 3.9 3.6 3.8 2.8 Melting time (s) 69 72 75 74 80 85 66 65 66 60 Foam stability ○ ○ ○ ○ × × △ △ △ × Effervescent (g / cm ² ) 0.45 0.45 0.44 0.43 0.57 0.68 0.70 0.69 0.72 0.71

Through Table 3, it was confirmed that the processing aids of Examples 1 to 4 carried out by introducing a multifunctional monomer according to the present invention are excellent in shortening the melt time, foamability, foam stability and flexural strength. When the polyfunctional monomer is introduced in excess as in Comparative Example 1 and Comparative Example 2, crosslinking occurs in the polymer chain, which is insoluble in the solvent, and it is confirmed that foaming stability and foamability are decreased due to the decrease in processability due to the crosslinking. When the amount of the multifunctional monomer is added or too little, as in Examples 3 to 6, it was confirmed that the effect on the molecular weight increase is reduced by the polymer chain reaction, and thus it is not improved in foamability, foam stability, and the like.

Example 5

In Example 1, the copolymer was prepared in the same manner as in Example 1 using 1,3-butylene glycol dimethacrylate as the multifunctional monomer to be used in the one-step batch reaction and the two-step batch reaction. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 7.5.

Example 6

In Example 1, the copolymer was prepared in the same manner as in Example 1 using 1,3-butylene glycol diacrylate as the multifunctional monomer to be used in the one-step batch reaction and the two-step batch reaction. After the reaction, the latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 7.8.

Example 7

In Example 1, a copolymer was prepared by polymerizing in the same manner as in Example 1 using divinylbenzene as the multifunctional monomer to be used in the one-step batch reaction and the two-step batch reaction. After the reaction, the latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 9.1.

Example 8

In Example 1, the copolymer was prepared in the same manner as in Example 1 using ethylene glycol dimethacrylate as the multifunctional monomer to be used in the one-step batch reaction and the two-step batch reaction. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a value of relative viscosity η _rel 7.9.

Example 9

In Example 1, the copolymer was prepared in the same manner as in Example 1 using diethylene glycol dimethacrylate as the polyfunctional monomer to be used in the one-step batch reaction and the two-step batch reaction. After the reaction, the latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 8.0.

Experimental Example 2

Physical properties were measured by the same method as Experimental Example 1 using the processing aids prepared in Examples 1 and 5 to 9 and Comparative Example 6, and the results are shown in Table 4 below.

division Example Comparative example One 5 6 7 8 9 6 Multifunctional Monomer AMA BDMA BDAA DVB EGDMA DEGDMA Relative viscosity η _rel 7.0 7.5 7.8 9.1 7.9 8.0 2.8 Melting time (s) 69 73 75 76 75 76 60 Foam stability ○ ○ ○ ○ ○ ○ × Effervescent (g / cm ² ) 0.45 0.46 0.46 0.55 0.50 0.49 0.71

As shown in Table 4, when the multifunctional monomer is used, it has a higher relative viscosity value than the case where it is not used, and shows much better properties in terms of foam stability and foamability. In the case of the polyfunctional monomer, it was also found that the asymmetric polyfunctional monomer showed somewhat better properties in foamability than the case of using the symmetric polyfunctional monomer.

Example 10

Example 1 using 1,3-butylene glycol dimethacrylate as the multifunctional monomer used in the two-step batch reaction to the aryl methacrylate to the multifunctional monomer used in the one-step batch reaction in Example 1 The polymerization was carried out in the same manner as in the copolymer. After the reaction, the latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 7.8.

Example 11

In the same manner as in Example 1 using aryl methacrylate as a multifunctional monomer as a multifunctional monomer used in the first step batch reaction in Example 1 and a polyfunctional monomer in a two-step batch reaction. Polymerization was made by polymerization. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 8.5.

Example 12

In Example 1, divinyl benzene was added as a multifunctional monomer in a one-step batch reaction, and ethylene glycol dimethacrylate was added as a multifunctional monomer in a two-step batch reaction to prepare a copolymer. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a value of relative viscosity η _rel 8.2.

Example 13

In Example 1, diethylene glycol dimethacrylate was added as a multifunctional monomer in a one-step batch reaction, and a copolymer was prepared by adding divinyl benzene as a multifunctional monomer in a two-step batch reaction. After the reaction, the latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 8.0.

Example 14

In Example 1, divinylbenzene was added as a multifunctional monomer in a one-step batch reaction, and an aryl methacrylate was added as a multifunctional monomer in a two-step batch reaction to prepare a copolymer. The reaction latex was agglomerated with calcium chloride (CaCl ₂ ), dehydrated and dried to obtain a powdery processing aid having a relative viscosity η _rel 8.5.

 Experimental Example 3

 Physical properties were measured in the same manner as in Experimental Example 1, using the processing aids prepared in Examples 10 to 14 and Comparative Examples 7 or 8, and the results are shown in Table 5 below.

division Example 10 11 12 13 14 Crosslinkable monomer Stage 1 BDMA DVB DEGDMA DVB EGDMA Tier 2 AMA EGDMA DVB AMA DEGDMA Relative viscosity η _rel 7.8 8.5 8.2 8.0 8.5 Melting time (s) 103 106 104 103 107 Foam stability ○ ○ ○ ○ ○ Effervescent (g / cm ³ ) 0.45 0.42 0.50 0.51 0.49

In Table 5, in the preparation of the processing aid for the thermoplastic resin, even when different multifunctional monomers were used in the one-stage batch reaction and the two-stage batch reaction, it was confirmed that excellent physical properties such as foaming stability and foamability were shown.

      As described above, the processing aid for the vinyl chloride resin produced according to the present invention can shorten the melting time without affecting the intrinsic properties of the vinyl chloride resin by introducing a polyfunctional monomer, and foaming in the extrusion foaming process. There is an effect that can satisfy the magnification and stability of the foaming cell at the same time, and also the present invention can produce a vinyl chloride-based resin composition in which the melting time is shortened by adding the processing aid, the foamability and the stability of the foaming cell is significantly improved. It is a useful invention that has an effect.

While the invention has been described in detail above with reference to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope and spirit of the invention, and such modifications and variations fall within the scope of the appended claims. It is also natural.

Claims (8)

60 to 86 parts by weight of methyl methacrylate; 14 to 39.9 parts by weight of one or more monomers selected from the group consisting of alkyl acrylates, alkyl methacrylates, and mixtures thereof; And 0.0001 to 0.1 parts by weight of at least one monomer selected from the group of multifunctional monomers; Processing aid composition of the vinyl chloride resin, characterized in that comprises a. The method of claim 1, The alkyl acrylate from the group consisting of methyl acrylate, ethyl acrylate, n-butyl acrylate, lauryl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate having 1 to 18 carbon atoms A processing aid composition of vinyl chloride resin, characterized in that at least one selected. The method of claim 1, The alkyl methacrylate is n-butyl methacrylate, lauryl methacrylate, stearyl methacrylate, tridecyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl meta A processing aid composition of vinyl chloride resin, characterized in that at least one selected from the group consisting of acrylates and cyclohexyl methacrylates. The method of claim 1, The group of the multifunctional monomer is aryl methacrylate, 1,3-butylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol di A processing aid composition of vinyl chloride resin, characterized in that consisting of methacrylate. The method of claim 1, A processing aid composition of vinyl chloride resin, characterized in that the relative viscosity of the processing aid of the vinyl chloride resin is η _rel 4.0 to 12.0. 69.9 to 95% by weight of methyl methacrylate, 4 to 30% by weight of one or more monomers selected from the group consisting of alkyl acrylates, alkyl methacrylates, and mixtures thereof, and one type selected from the group of polyfunctional monomers Step 1 to prepare a copolymer consisting of 0.0001 to 0.1% by weight of the monomers; And In the presence of the copolymer made in step 1, from 54.9 to 70% by weight of methyl methacrylate, from 29 to 45% by weight of at least one monomer selected from the group consisting of alkyl acrylates, alkyl methacrylates, and mixtures thereof, And 0.0001 to 0.1% by weight of at least one monomer selected from the group of multifunctional monomers. Process for producing a processing aid of vinyl chloride resin, characterized in that comprises a.       The method of claim 6,       25 to 35 parts by weight of the copolymer prepared in step 1; And      Method for producing a vinyl chloride resin processing aid, characterized in that for preparing a vinyl chloride resin processing aid comprising 65 to 75 parts by weight of the copolymer prepared in step 2.       A vinyl chloride resin composition comprising 0.1 to 20 parts by weight of a processing aid of the vinyl chloride resin of any one of claims 1 to 5 and 100 parts by weight of a polyvinyl chloride resin.