MXPA00004134A - Processing aid for vinyl chloride resin and vinyl chloride resin composition containing the same - Google Patents

Abstract

A processing aid for vinyl chloride resins which comprises a polymer mixture having a specific viscosity&eegr;sp of 0.5 or higher obtained by emulsion-polymerizing 50 to 99 parts by weight of a monomer mixture (A) consisting mainly of methyl methacrylate to obtain a latex of a (co)polymer having a specific viscosity&eegr;sp of 0.7 or higher, adding 50 to 1 part by weight of a monomer mixture (B) consisting mainly of one or more (meth)acrylic esters excluding methyl methacrylate to the latex, and polymerizing the monomer mixture (B) in the presence of the latex, the total amount of mixtures (A) and (B) being 100 parts by weight;and a vinyl chloride resin composition which comprises the processing aid and a vinyl chloride resin and gives a (foamed) molding excellent in processability and physical properties.

Description

AUXILIARY PROCESSING FOR VINYL CHLORIDE RESIN AND COMPOSITION OF VINYL CHLORIDE RESIN TECHNICAL FIELD The present invention relates to a processing aid for a vinyl chloride resin and a vinyl chloride resin composition containing the processing aid (and a foaming agent) having excellent processability, and which can provide a processed item that has excellent physical properties or a shaped article that has satisfactory properties. Particularly, the invention relates to a processing aid for a vinyl chloride resin comprising methyl methacrylate, a methacrylate ester except for methyl methacrylate and / or an acrylate ester as a main component, and a resin composition of vinyl chloride containing the processing aid, a vinyl chloride resin, and a foaming agent as an optional component.

ANTECEDENTS OF THE TECHNIQUE A vinyl chloride resin has been widely used in various fields, because it can produce a processed article that has excellent physical and chemical properties. However, there are problems in processing such as a narrow-scale processing temperature and slow melting, because the processing temperature is close to the decomposition temperature thereof. Recently many technologies have been developed, which counteract the aforementioned processing problems. Examples of typical technologies are a method of adding a plasticizer to a vinyl chloride resin, a method employing a vinyl chloride resin copolymerized with another monomer such as vinyl acetate, and a method that mixes a chloride resin of vinyl with another component of resin. However, all these methods can not improve the processability satisfactorily while maintaining the excellent chemical and physical properties that the vinyl chloride resin originally has. For example, in the case of the addition of a plasticizer to a vinyl chloride resin, or of using a vinyl chloride resin copolymerized with another monomer, the physical property of the processed article changes drastically. Most methods of mixing a vinyl chloride resin with another resin component is a method of lowering the processing temperature by decreasing the melt viscosity in the mold processing. Obviously, the flowability of a vinyl chloride resin improves, but the gelation of a vinyl chloride resin becomes unsatisfactory due to the consumption of the mixing energy through the fluidity. Therefore, in applications where transparency is required, there is a problem that the physical property thereof is inferior to that of the fully gelled vinyl chloride resin even if the prepared processed article thereof becomes transparent. In order to solve the aforementioned problems, Japanese Examined Patent Publication No. 5311/1965 discloses a method of adding, as a processing aid, a copolymer of methyl methacrylate as a main component having a comparatively high molecular weight. Although the aggregate processing aid is apt to be left as a non-gelled object (usually called "fish eye") in the processed article, it is easy to lose the appearance of molding. And the other effects of adding a processing aid, such as improved gloss of the product, improvement of the secondary processing capacity, and the specific gravity decrease by foam molding, do not present satisfactorily. And the patent publication examines Japanese number 49020/1977 and no. 2898/1978 discloses a composition containing a processing aid prepared by two step polymerization. First a larger amount of methacrylate ester is polymerized followed by the polymerization of a lower amount of acrylate ester in the presence of a poly (methyl methacrylate) latex or a copolymer of a larger amount of methyl methacrylate and a minor acrylate ester. The method was effective in the prevention of the non-gelled object mentioned above, however the effect of it was not satisfactory. And depending on the mixing and application, various problems arise due to unsatisfactory dispersion of a processing aid in a vinyl chloride resin composition, such as decreased molding transparency of a vinyl chloride resin, decrease in the ratio of gelation, and decrease in secondary processing capacity such as elongation at a high temperature. Recently, foam molding has attracted considerable attention as a method to decrease a density of a processed article and decrease the cost of molding. In the above-mentioned foam molding of a vinyl chloride resin, a method is known which employs a processing aid containing methyl (meth) acrylate as a main component and a foaming agent. However, it was difficult to increase the expansion ratio to no less than 3 times maintaining the uniformity of the molding appearance, and the uniformity and size of the foam cell. On the other hand, the foam molding of a vinyl chloride resin having a higher expansion ratio has been in great demand in the market. As described in Japanese Examined Patent Publication Number 531 1/1965, it is known that the processing capacity can be improved by adding a copolymer comprising methyl methacrylate as a major component having a high molecular weight to a vinyl chloride resin . It can be expected that the higher the molecular weight, the greater the effect of it. But in the case of employing the processing aid having slightly increased the molecular weight, not only the transparency, but also a gel ratio thereof can be decreased and also the secondary processing capacity such as elongation at a high temperature. In this way, it is not always practical. The influence of a microstructure of the processing aid in the final composition has never been fully understood. But it must be the reason that the dispersion capacity becomes lower by increasing the molecular weight of it.

BRIEF DESCRIPTION OF THE INVENTION With respect to the aforementioned circumstances, a processing aid is investigated from the composition thereof, so that the gelling property, processability and foaming capacity of the composition can be improved by adding a small amount of the auxiliary. prosecution. It has also been found that the aforementioned objects are achieved by employing, as a processing aid, the polymer whose outer layer is formed by the polymerization of a particular amount of monomer in the presence of a latex of a satisfactory polymerized (co) polymer having a particular composition comprising methyl methacrylate as a main component. Primarily, the present invention relates to a processing aid for a vinyl chloride resin having a specific viscosity? Sp of at least 0.5, which is obtained by polymerizing from 1 to 50 parts by weight of a monomer mixture (B) comprising from 0 to 49% by weight of methyl methacrylate, from 51 to 100% by weight of at least one monomer selected from the group consisting of a methacrylate ester except methyl methacrylate and an acrylate ester, and 0 to 20% by weight of a vinyl monomer copolymerizable therewith, in the presence of a latex of a (co) polymer having specific viscosity? sp of at least 0.7, which is obtained by polymerizing in emulsion of 99 to 50 parts by weight of a monomer mixture (A) comprising from 51 to 100% by weight of methyl methacrylate, from 0 to 49% by weight of at least one monomer selected from the group consisting of a methacrylate ester except methyl methacrylate and an acrylate ester, and from 0 to 20% by weight of a vinyl monomer copolymerizable therewith, wherein the total amount of ( A) and (B) is 100 parts (claim 1), the processing aid according to claim 1, wherein the processing aid for a vinyl chloride resin is a processing aid for a sodium chloride resin. vinyl containing a foaming agent (claim 2), a vinyl chloride resin composition comprising 100 parts by weight of a vinyl chloride resin and from 0.1 to 30 parts by weight of the processing aid in accordance with claim 1 (claim 3), and a vinyl chloride resin composition containing a foaming agent comprising 100 parts by weight of a vinyl chloride resin, from 0.1 to 30 parts by weight of the processing aid in accordance with claim 1 and a foaming agent (claim 4).

DETAILED DESCRIPTION OF THE INVENTION The feature of the present invention is to employ a mixture of (co) polymer as a processing aid for a vinyl chloride resin, wherein the mixture of (co) polymer (hereinafter referred to as "polymer mixture prepared by two-step polymerization ") is obtained by adding and polymerizing a monomer mixture (B) containing a greater amount of at least one monomer selected from the group consisting of a methacrylate ester except methyl methacrylate and an acrylate ester, the presence of a (co) polymer (hereinafter referred to as "polymer mixture in the first step") obtained by polymerizing in emulsion a monomer mixture (A) containing a greater amount of methyl methacrylate as a component of the first step . The polymer mixture in the first step and in the second step, respectively, have not less than 0.7 and 0.5 of specific viscosity at 30 ° C, measured using 100 ml of chloroform solution containing 0.1 g of the polymer mixture. Using the polymer blend prepared by the two step polymerization as a processing aid for a vinyl chloride resin, the following effects can be remarkably expressed, which are expected to be obtained by adding a processing aid. (1) The gelation can be promoted and the secondary processing capacity can be improved by adding a small amount of it without losing the physical and chemical property, which has a vinyl chloride resin originally. (2) The specific gravity in foaming can be reduced. (3) The brightness of a product can be improved. The processing aid of the present invention comprises a polymer mixture prepared by the two-step polymerization, which is obtained by polymerizing a mixture of monomer (B) in the presence of a latex of a polymer in the first step obtained by emulsion polymerizing a mixture. of monomer (A). The monomer mixture (A) comprises from 51 to 100% by weight, preferably from 60 to 90%, most preferably from 70 to 85% by weight of methyl methacrylate, from 0 to 49% by weight, preferably from 0 to 40. % by weight, most preferably from 0 to 30% by weight of at least one monomer selected from the group consisting of a methacrylate ester except methyl methacrylate and an acrylate ester, and from 0 to 20% by weight, preferably 0 to 10% by weight, most preferably 0 to 5% by weight of a vinyl monomer copolymerizable therewith. If the ratio of methyl methacrylate in the monomer mixture (A) is less than 51% by weight, transparency and processability are reduced. On the other hand, if the monomer selected from the group consisting of a methacrylate ester except methyl methacrylate and an acrylate ester is more than 49% by weight, transparency and processability are reduced. And if the copolymerizable vinyl monomer thereof is more than 20% by weight, the gel property and the transparency are reduced. As the methacrylate ester except methyl methacrylate in the monomer mixture (A), some examples are an alkyl methacrylate ester having from 2 to 8 carbon atoms of an alkyl group such as ethyl methacrylate, propyl methacrylate, butyl methacrylate or 2-ethylhexyl methacrylate, and the like. And examples of an acrylate ester are alkyl acrylate having from 1 to 8 carbon atoms of an alkyl group such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate or 2-ethylhexyl acrylate, and the like . This methacrylate ester except methyl methacrylate and acrylate ester can be used alone or in combination using two or more thereof.

As the vinyl monomer copolymerizable therewith in the monomer mixture (A), examples are an aromatic vinyl compound such as styrene and α-methylstyrene, and an unsaturated nitrile compound such as acrylonitrile. These can be used alone or in combination using two or more of them. The specific viscosity? Sp of the (co) polymer (polymer in the first step) obtained by emulsion polymerizing a monomer mixture (A) is at least 0.7, preferably from 0.7 to 1.9, most preferably from 0.8 to 1.8, particularly from 0.9 to 1.7. The specific viscosity is measured at 30 ° C using 100 ml of a chloroform solution containing 0.1 g of the polymer mixture. If the specific viscosity is less than 0.7, the processing capacity can not be satisfactorily improved. And if the viscosity is more than 1.9, transparency and processing capacity tend to decrease. The monomer mixture (B) comprises from 0 to 49% by weight, preferably from 20 to 49% by weight, most preferably from 30 to 45% by weight of methyl methacrylate, from 51 to 100% by weight, preferably from 51 at 80% by weight, most preferably from 55 to 70% by weight of at least one monomer selected from the group consisting of a methacrylate ester except methyl methacrylate and an acrylate ester, and from 0 to 20% by weight, preferably from 0 to 10% by weight, most preferably from 0 to 5% by weight of the vinyl monomer copolymerizable therewith.

By polymerizing a monomer mixture (B) in the presence of a polymer latex in the first step to prepare a (co) polymer comprising the mixture (B) outside the polymer in the first step, gelation can be promoted and the product prevented from ungelled occurs in case of adding the processing aid to a vinyl chloride resin. As a result, the viscosity and elasticity can be effectively delivered to a vinyl chloride resin. If a ratio of methyl methacrylate in the monomer mixture (B) is more than 49% by weight, the excellent gelling property can be lost or the ungelled product easily occurs. If the monomer selected from the group consisting of a methacrylate ester except methyl methacrylate and an acrylate ester is less than 51% by weight, the same phenomenon occurs. And, if necessary, the vinyl monomer copolymerizable therewith can be used in an amount of less than 20% by weight. However, the amount thereof is preferably as low as possible. Examples of the methacrylate ester except methyl methacrylate in the monomer mixture (B), are an alkyl methacrylate ester having from 2 to 8 carbon atoms of an alkyl group such as ethyl methacrylate, propyl methacrylate, methacrylate Butyl, 2-ethylhexyl methacrylate, and similar. And examples of the acrylate ester are an alkyl acrylate ester having from 1 to 8 carbon atoms of an alkyl group such as methyl acrylate, ethyl acrylate, propyl acrylate, propyl acrylate, butyl acrylate or sodium acrylate. -ethylhexyl, and the like. This methacrylate ester except methyl methacrylate and acrylate ester can be used alone or in a combination of 2 or more thereof. Among these, butyl acrylate is preferred from the viewpoint of obtaining a polymer having a low glass transition temperature. As the vinyl monomer copolymerizable therewith in the monomer mixture (B), some examples are an aromatic vinyl compound such as styrene or α-methylstyrene, and a nitrile-unsaturated compound such as acrylonitrile. These can be used alone or in combination of two or more of these. A ratio of the monomer mixture (A) to the monomer mixture (B) is 50 to 99 parts by weight, preferably 60 to 95 parts by weight, most preferably 65 to 90 parts by weight of the monomer mixture (A), and from 1 to 50 parts by weight, preferably 5 to 40 parts by weight, most preferably from 10 to 35 parts by weight of the monomer mixture (B), wherein the total part is 100 parts. If the amount of the monomer mixture (A) (polymer in the first step) is more than 99 parts by weight, the dispersion capacity of the processing aid to a vinyl chloride resin decreases, and the ungelled product occurs. . On the other hand, if the amount is less than 50 parts by weight, the gelling property of the vinyl chloride resin can not be satisfactorily improved. And if the amount of the (co) polymer (polymer prepared by two step polymerization) prepared from the monomer mixture (B) is more than 50 parts by weight, the gel property and the transparency of the chloride resin composition of vinyl decrease. On the other hand, if the amount is less than 1 part by weight, the dispersion capacity of the processing aid to a vinyl chloride resin decreases, and the ungelled product occurs. Because the (co) polymer prepared from a monomer mixture (B) is the external part of the polymer in the first step, the gelling property and the processing capacity can be markedly improved. As a result, the effect of adding the processing aid of the present invention can be markedly improved. For example, the processing aid of the present invention can be prepared by the following method. First, a monomer mixture (A) is polymerized in emulsion in the presence of a suitable solvent, an emulsifier, a polymerization initiator and a chain transfer agent to obtain a polymer latex in the first step prepared from the mixture of monomer (A). Then, a monomer mixture (B) is added in the polymer latex in the first step to initiate the polymerization. The polymer mixture prepared by the two step polymerization, wherein the polymer in the first step is an inner layer and the (co) polymer prepared from the monomer mixture (B) is an outer layer, is prepared by polymerizing each mix one by one.

The polymerization medium used in the emulsion polymerization is generally water. As the emulsifier, the conventional emulsifier can be employed. Examples thereof are an anionic surfactant such as a fatty acid salt, an alkyl sulfate salt, an alkylbenzenesulfate salt, an alkyl phosphate salt or a sulfosuccinate diester salt, a nonionic surfactant such as a polyoxyethylene alkyl ether or acid ether. polyoxyethylene fatty acid. As the polymerization initiator, examples are a water soluble polymerization, an oil soluble polymerization initiator and the like. For example, an inorganic polymerization initiator such as a conventional persulphonate salt, an organic peroxide, or an azo compound can be used separately. These initiator compounds can be used as a redox type by combining it with a sulfite salt, a thiosulfate salt, a metal primary salt or sodium formaldehyde sulfoxylate. As an extremely preferred persulphonate salt, examples are sodium persulfonate, potassium persulphonate, ammonium persulphonate and the like. As a preferred organic peroxide compound, examples are t-butyl hydroperoxide, eumenohydroperoxide, benzoyl peroxide, lauroyl peroxide and the like. There is no particular limitation for the chain transfer agent mentioned above. Examples thereof are t-dodecyl mercaptan, t-decylmercaptan, n-dodecyl mercaptan, n-decylmercaptan and the like.

There is no particular limitation for the time and temperature of the polymerization reaction mentioned above. And these can be suitably controlled in such a way that the desired specific viscosity and the desired particle diameter can be achieved. In case of adding a monomer mixture (B), the polymerization in each step can be carried out by confirming the conclusion of the first polymerization step without mixing a monomer mixture (A) with the monomer mixture (B). The latex obtained from the polymer mixture prepared by the two step polymerization has an average particle diameter of 100-3000A, preferably 100-2000A. The polymer mixture is removed from the latex by stirring the salt or coagulating the addition of a conventional electrode, or by sprinkling in a hot air or dryer. If necessary, the mixture is washed, dehydrated and dried by the conventional method. The specific viscosity of the obtained polymer mixture prepared by the two step polymerization is at least 0.5, preferably 0.5 to 1.7, most preferably 0.6 and 1.6, particularly preferred 0.7 to 1.5. The specific viscosity is measured at 30 ° C using 100 ml of a chloroform solution containing 0.1 g of the polymer mixture. If the viscosity is less than 0.5, the processing capacity can not be improved satisfactorily. On the other hand, if the viscosity is greater than 1.7, the transparency and the processing capacity tend to decrease.

The white powder having an average diameter of 20 to 300 μm is generally separated from the obtained polymer mixture prepared by the two step polymerization, and then mixed as a processing aid with a vinyl chloride resin or a vinyl chloride resin containing a foaming agent. The processing aid of the present invention is mixed with a vinyl chloride resin by the conventional method for preparing the vinyl chloride resin composition of the present invention. A mixing ratio of the vinyl chloride resin to the processing aid is from 0.1 to 30 parts by weight of the processing aid, preferably from 0.5 to 20 parts by weight, most preferably from 1 to 10 parts by weight based on 100. parts by weight of the vinyl chloride resin. If the amount thereof is less than 0.1 parts by weight, the effect can not be obtained satisfactorily. On the other hand, if the amount is more than 30 parts by weight, the excellent mechanical property of the vinyl chloride resin is reduced. As the vinyl chloride resin, one example is a polymer comprising from 80 to 100% by weight of a vinyl chloride monomer unit from 0 to 20% by weight of another monomer unit copolymerizable therewith.

As the other monomer copolymerizable therewith, examples are vinyl acetate, propylene, styrene, acrylate and the like. These can be used alone or in a combination of two or more thereof. There is no particular limitation for an average molecular weight of the vinyl chloride resin, and the conventional vinyl chloride resin can be suitably employed. Examples thereof are polyvinyl chloride, a copolymer comprising at least 80% by weight of a vinyl chloride monomer and the other vinyl copolymerizable therewith (for example, vinyl acetate, propylene, styrene) , acrylate ester), and post-chlorinated polyvinyl chloride, and the like. These can be used alone or in a combination of two or more thereof. In case of preparing the vinyl chloride resin composition, a foaming agent may be added to prepare the vinyl chloride resin composition containing a foaming agent. In this case, the processing aid can be used as the processing aid for the vinyl chloride resin composition containing a foaming agent. There is no particular limitation for an amount of the foaming agent in the vinyl chloride resin composition containing a foaming agent, and the amount is conveniently determined depending on the object. If the quantity is very low, a processed item that has a sufficient expansion ratio can not be obtained. On the other hand, if the amount is very high, a uniform foam molding can not be obtained. In this way, the amount thereof is generally from 0.2 to 6 parts by weight based on 100 parts by weight of the vinyl chloride resin. In this case, an expansion ratio of foam molding becomes from 2 to 5 times. As the foaming agent which is employed in the present invention, preferred examples are an inorganic foaming agent of the thermal decomposition type and an organic foaming agent of the thermal decomposition type. Examples of the inorganic foam forming agent of the thermal decomposition type are, for example, sodium bicarbonate, ammonium bicarbonate, ammonium carbonate and the like. Examples of the organic foam forming agent of the thermal decomposition type are, for example, a nitroso compound such as N, N'-dinitrosopentamethylenetetramine or N.N'-dimethyl-N.N'-dinitrosoterephthalamide, an azo compound such as azodicarboxylamide or azobisisobutyronitrile, a sulfonylhydrazide compound such as benzenesulfonylhydrazide or toluenesulfonylhydrazide, and the like. Different examples of the aforementioned agent are an inert gas such as carbon dioxide or nitrogen, and a foaming agent of the organic solvent type such as propane, butane, pentane, methyl chloride, chloroform, trichlorethylene or chloromethane. These can be used alone or in a combination of two or more thereof. A stabilizer, a lubricant, an impact modifier, a plasticizer, a colorant and a filler, can practically be added to the vinyl chloride resin composition (which contains a foaming agent as an optional component) of the present invention, If necessary. The vinyl chloride resin composition (which contains a foaming agent as an optional component) of the present invention is excellent in processability, and can be processed by blow molding, injection molding, calendering or extrusion. Because the obtained processed article is excellent in appearance such as transparency, gloss or smooth surface, and secondary processing capacity, and a molding having low specific gravity can be obtained in case of foam molding, the resin composition can be applied to all fields employing a vinyl chloride resin such as film, sheet and profile extrusion. Especially, from the point of view of low specific gravity and smooth surface, the composition can preferably be used for the preparation of foam articles. The present invention is specifically explained by examples and comparative examples, however the examples do not limit the present invention. "Parts" in the examples means "parts by weight" unless otherwise specified. The evaluation articles and evaluation methods used in the examples and in the comparative examples are as mentioned below.

[Measurement of specific viscosity (r?) \ In 100 ml of chloroform, 0.1 g of a sample was dissolved and the viscosity was measured using a Viscométro of Ubbelohde keeping at a constant temperature in a water bath at 30 ° C.

[Qualification property] To 100 parts by weight of poly (vinyl chloride) (average molecular weight 680) were added 6.0 parts of a processing aid, 5.0 parts of calcium carbonate, 3.0 parts of titanium oxide, 3.0 parts of phosphite of lead dibasic, 0.4 parts of lead stearate, 0.8 parts of calcium stearate, 0.3 parts of hydroxystearic acid (LOXIOL G-21 available from Henkel company), an aliphatic carboxylate ester (LOXIOL G-32 available from Henkel company), 0.4 parts of dibasic ester of an aliphatic alcohol (LOXIOL G-60 available from Henkel company) and 0.5 parts of oxidized polyethylene wax (Hoechst-Wachs PED-521 available from Hoechst), and then mixed by a Henschel mixer. After the internal temperature was increased to 110 ° C, the mixture was cooled to obtain a powdery compound. The gelation property was evaluated by tilting a straight line between a maximum torque and a minimum torque over kneading time versus torque curve, which was obtained by kneading 62 g of the powder compound obtained at 150 ° C using a small kneading machine (Plasticoder PLE-331 developed by Brabender). It was judged that the gelation property was better in the case of a greater inclination.

[Transparency] To 100 parts of poly (vinyl chloride) (average molecular weight 680) were added 3.0 parts of a processing aid, 1.5 parts of an octyltin mercaptide stabilizer, 1.5 parts of an epoxidized soybean oil, 1.0 parts of butyl steatate and 0.5 parts of a polyethylene glycol fatty acid ester, and then they were mixed using a Henschel mixer. After the internal temperature was increased to 1 10 ° C, the mixture was cooled to obtain a powdery compound. The vinyl chloride resin composition was milled at 170 ° C for five minutes by a 20.32 cm test roller, and then pressed at 180 ° C for fifteen minutes to prepare a compressed plate that was 3 mm thick. All light transmittance and nebulosity of the pressed plate obtained was measured according to JIS-6714. It is indicated that the transparency is excellent in the case of a higher light transmittance. And also it is indicated that the transparency is better in the case of a minor nebulosity.

[Foaming ability] To the compound used in the evaluation of the gelation property was added 1.0 parts of azo dicarboxylamide to obtain a powdery compound in the same manner as the aforementioned method. And then the compound was extruded at 170 ° C by means of a small conical screw extruder (2D20C) attached to a laboratory plasta mill (developed by Toyoseiki company) to produce a foam profile. The specific gravity of the obtained profile was measured. It was indicated that the expansion ratio is higher and the capacity of foaming is better in the case of the lower specific gravity.

EXAMPLE 1 To an 8-liter reactor equipped with a stirrer were added 0. 7 parts of sodium dioctylsulfosuccinate previously dissolved in water. Additional water was added in a total amount of 200 parts, wherein the amount includes an amount of water contained in an additional material added later. After the air was replaced by nitrogen gas e? the reactor, the contents were heated to 70 ° C with stirring. Then, a monomer mixture (A) comprising 60 parts of methyl methacrylate (MMA) and 20 parts of butyl acrylate (BA) was simultaneously added to the reactor. After 0.005 parts of potassium persulfate were added, stirring was continued for one hour to substantially conclude the polymerization. A mixture of monomer (B) comprising 6 parts of MMA and 14 parts of BA at a rate of about 30 parts per hour was continuously added to the mixture. After concluding the addition of monomer mixture (B), the content was maintained at 70 ° C for 90 minutes, and cooled to obtain a polymer latex. The polymerization conversion was 99.5%. The obtained latex was coagulated by an aqueous solution of calcium chloride. Then the latex was heated to 90 ° C, and filtered by a centrifuge. The dehydrated cake obtained from the polymer mixture was washed with the same amount of water as the mixture, and then dried at 50 ° C for 15 hours by a parallel fluid drier to obtain a sample of white powder (1). The aforementioned evaluations were carried out using the sample obtained. Table 1 shows the results with the composition of the products. The abbreviations in Table 1 indicate the following: MMA: methyl methacrylate BA: butyl acrylate BMA: butyl methacrylate EA: ethyl acrylate AN: acrylonitrile EXAMPLE 2 TO 7 AND COMPARATIVE EXAMPLES 1 TO 3 According to the compositions shown in the box 1, samples 2 to 10 were obtained in the same manner as in example 1. The aforementioned evaluations were carried out for the samples obtained. Table 1 shows the results of the same.

TABLE 1 Composition (parts)? Sp Transparency Mués Polymer Polymer Diameter of Transmittance Value of Capacity of -tra Mixture of monomer (A) or mixture Mixture of in the particle of total light (%) nebulosity gelation formation of corresponding monomer (B) first second average of ad (%) (Nm / min.) foam No Step step Latex (A) (g / cm3) MMA BMA BA EA AN St MMA BA Ej. No. 1 (D 60 - 20 - - - 6 14 1.11 0.80 1600 72.5 15.5 8.21 0.43 2 (2) 65 - 10 - 5 - 6 14 1.13 0.84 1600 69.6 15.5 8.14 0.45 3 (3) 65 10 - - - 5 6 14 1.12 0.80 1500 69.6 15.5 8.02 0.46 4 (4) 68 - - 12 - - 6 14 1.12 0.80 1600 68.7 15.7 8.12 0.44 (5) 65 - - 5 10 - 6 14 1.11 0.81 1700 68.9 15.6 8 08 0.46 6 (6) 70 - 4 - - 6 6 14 1.11 0.82 1500 68.2 16.2 5.21 0.50 7 (7) 75 - - - 5 - 6 14 1.06 0.79 1600 67.5 29.6 4.80 0.55 Ex. Com No. 1 (8) 24 - 56 - - - 6 14 1.11 0.80 1600 50.0 25.2 2.56 0.88 2 0) 32 - 48 - - - 6 14 1.12 0.82 1600 58.3 21.4 2.88 0.85 3 (10) 48 - - 12 - 20 6 14 1.03 0.80 1700 59.7 22.4 2.67 0.80 As is evident from the results of Table 1, it is possible to observe that the composition having excellent gelling property and foaming capacity can be obtained using samples 1 to 7, but the gelling property and foaming capacity decrease using samples 8 to 10 prepared from a monomer mixture (A) in an amount such that a ratio of a methacrylate other than methyl methacrylate, an acrylate and a vinyl monomer copolymerizable therewith is greater than the scale of the present invention.

EXAMPLES 8 TO 12 AND COMPARATIVE EXAMPLES 4 TO 6 According to the compositions shown in table 2, samples 11 to 18 are obtained in the same manner as in example 1. The aforementioned evaluations were carried out for the samples obtained. Table 2 shows the results of the same.

TABLE 2 Composition (parts)? Sp Transparency Mués Mixture of monomer mixture (B) or mixture Polymer Polymer Diameter of Transmittance Value of Capacity property of -tra monomer (A) corresponding in the particle of total light (%) nebulosity gelation formation First second second average (%) (Nm / min.) foam (g / cm) Step no. Latex step (A) MMA BA MMA BMA BA EA AN St No. 8 (11) 68 12 10 1.12 0.84 1600 72.0 15.1 8.14 0.43 9 (12) 68 12 8 1.12 0.82 1600 72.2 15.1 8.02 0.44 10 (13) 68 12 13 1.13 0.83 1600 69.5 15.5 7.99 0.47 11 (14) 68 12 13 1.13 0.85 1600 69.3 15.6 7.89 0.47 12 (15) 68 12 15 1.07 0.78 1500 67.0 18.2 7.24 0.50 Ex. Com. No. 4 (16) 68 12 16 4 1.12 0.80 1600 58.6 22.6 6.13 0.77 C? (17) 68 12 18 2 1.13 0.82 1600 55.2 25.8 5.93 0.82 6 (18) 68 12 12 1.09 0.78 1600 53.3 28.2 4.26 0.95 As is clear from the results in Table 2, it can be seen that the composition having excellent gelling and foaming property can be obtained in an amount that a composition of a corresponding monomer mixture (B) is on the scale of the present invention as in samples 11 to 15. On the other hand, it is observed that the transparency, gel property and foaming capacity are decreased using samples 16 to 18 prepared from the monomer mixture (B), whose composition is not in the scale of the present invention.

EXAMPLE 13 TO 16 AND COMPARATIVE EXAMPLES 7A 8 According to the compositions shown in Table 3, samples 19 to 24 are obtained in the same manner as in Example 1. The aforementioned evaluations are carried out for the samples obtained. Table 3 shows the results of the same.

TABLE 3 Composition (parts) Isp Transparency Sample Mixture of Polymer Polymer Mix in Transmittance Diameter Property V Capacity of monomer No. (A) monomer (B) the first the second total light particle formation nebulosity-step average t ° /? (%) gelation foam MMA .ßA_ MMA _B? _ Latex (A) (Nm / min) Ex. No. 13 (19) 51 9 i: 28 1.23 0.80 1500 48.2 32.1 7.89 0.56 14 (20) 60 10 9 21 1.18 0.79 1500 67.2 16.7 8.14 0.47 15 (21) 68 12 6 14 1.12 0.84 1600 71.5 15.2 8.20 0.45 16 (22) 77 13 3 7 1.06 0.82 1600 67.5 16.6 8.02 0.50 Ex. No. f < , 7 (23) 32 8 18 42 1.35 0.80 1600 35.3 35.2 3.21 0.85 03 ' 8 (24) 24 6 21 49 1.42 0.78 1600 28.4 38.2 3.13 0.91 As is clear from the results of Table 3, it can be seen that the composition having excellent gelling and foaming property can be obtained in an amount that a composition of a monomer mixture (A) is on the scale of the present invention as in samples 19 to 22. On the other hand, it can be seen that the gelling property and foaming ability are not satisfactory in case an amount of a monomer mixture (A) is smaller than the scale of the present invention as in samples 23 and 24.

EXAMPLES 17 TO 20 According to the compositions shown in Table 4, samples 25 to 28 were obtained in the same manner as in Example 1. The aforementioned evtions were performed for the samples obtained. Table 4 shows the results of the same.

COMPARATIVE EXAMPLE 9 An 8-liter reactor equipped with an agitator was charged with 0.5 parts of sodium dioctylsulfosuccinate previously dissolved in water, 0.03 parts of potassium persulfate and additional water in an amount that a total amount of water becomes 200 parts. After the oxygen was replaced with nitrogen gas in the reactor, the contents were heated to 70 ° C with stirring. Then, a monomer mixture (A) comprising 68 parts of MMA and 12 parts of BA was added to the reactor continuously at a rate of about 30 parts per hour. After concluding the addition of monomer mixture (A), stirring was continued for one hour to substantially conclude the polymerization. A mixture of monomer was continuously added to the mixture.

(B) comprising 6 parts of MMA and 14 parts of BA at a speed of about 30 parts per hour. After concluding the addition of monomer mixture (B) the content was maintained at 70 ° C for 90 minutes, and cooled to obtain a latex. The polymerization conversion was 99.4%. The obtained latex was coagulated by an aqueous solution of calcium chloride in the same manner as in Example 1. After the latex was heated to 90 ° C, it was filtered by a centrifuge. The dehydrated cake obtained from the polymer mixture was washed with the same amount of water as a mixture, and then dried at 50 ° C for 15 hours by a parallel fluid drier to obtain a white powder sample (29). The aforementioned evtions were carried out using the sample obtained. Table 4 shows the results of the same.

COMPARATIVE EXAMPLES 10 According to the compositions shown in Table 4, sample 30 was obtained in the same manner as in Example 9. The evtions mentioned above were carried out for the sample obtained. Table 4 shows the results of the same.

TABLE 4 Composition (parts)? SD Transparency Sample Emulsifier Primer Diameter Propied Capacit. No. (parts) (parts) of particle ad gelling gel, latex averaging (Nm / foam (A) min.) (G / cm3 ) Mixture of Polymer Polymer Mix Transmi monomer monomer v in the batch of (A) (B) first second light nebulopaso total passage sidad (%) (%) MMA BA MMA BA Ej. No. or 17 (25) 68 12 6 14 0.05 0.7 0.92 0.63 1600 69.8 15.8 6.23 0.51 18 (26) 68 12 6 14 0.01 0.7 1.01 0.73 1500 71.2 15.2 7.02 0.45 19 (27) 68 12 6 14 0.005 0.7 1.13 0.84 1600 70.8 15.4 8.14 0.43 20 (28) 68 12 6 14 0.001 0.7 1.22 1.00 1600 70.5 15.5 8.26 0.42 Com. Ex- No. 9 (29) 68 12 6 14 0.03 0.5 0.71 0.43 1500 71.8 15.0 5.37 0.82 10 (30) 68 12 6 14 0.1 0.5 0.63 0.32 1600 71.9 15.0 4.02 0.89 As it is evident from the results of table 4, it can be observed that the capacity of foaming is not satisfactory in the case of the sample (29), where the polymer sp in the first step is at least 0.7. and? sp of the polymer in the second step is less than 0.5, and the sample (30), where? sp of the polymer in the first step is less than 0.7 and? sp of the polymer in the second step is less than 0.5 In this way, it is concluded that? Sp of the polymer in the first step should be at least 0.7 and? Sp of the polymer in the second step should be at least 0.5.

EXAMPLES 21 TO 23 AND COMPARATIVE EXAMPLES 11 TO 12 In order to evaluate an effect of the mixing ratio of the sample (1) used in Example 1 with a vinyl chloride resin, the effect was evaluated in the same manner as mentioned above except that 6.0 parts of the sample ( 1) in the evaluation method changes to a mixing ratio described in table 5. However, in comparative example 12 the processed articles suitable for the evaluation of transparency and foaming capacity were not obtained, because it decreased the uniformity of the composition. Table 5 shows the results.

TABLE 5 Transparency Sample Transmittance Amount Capacity Value of Capacity to No. combination of total light nebulosity gelation of (parts) (%) (%) (Nm / min) foam formation (g / cnr) Ex. No. 21 (D 0.5 70.2 16.4 3.23 0.82 22 (D 6 72.5 15.5 8.21 0.43 23 (D 15 68.3 16.8 8.14 0.46 No. 11 (D 0.01 50.5 16.8 1.42 1.02 12 (D 40 - - - - As is evident from the results of Table 5, it can be seen that the composition mixed with the sample 1 in an amount of the present invention has excellent transparency, gelling property and foaming ability. It can also be seen that the gelling property and the foaming ability are not satisfactory in a minor amount of the present invention as in comparative example 1 1.

Industrial Application Capability The resin composition containing the processing aid of the present invention is excellent not only in transparency but also in gelling property and foaming ability. The resin composition having such excellent properties can be prepared by adding a small amount, from 0.1 to 30 parts by weight, of the processing aid based on 100 parts by weight of the vinyl chloride resin.

Claims (4)

NOVELTY OF THE INVENTION CLAIMS

1. - A processing aid for a vinyl chloride resin having a specific viscosity ρ sp of at least 0.5, which is obtained by polymerizing from 1 to 50 parts by weight of a monomer mixture (B) comprising from 0 to 49% by weight of methyl methacrylate, from 51 to 100% by weight of at least one monomer selected from the group consisting of a methacrylate ester except methyl methacrylate and an acrylate ester, and from 0 to 20% by weight of a vinyl monomer copolymerizable therewith, in the presence of a latex of a (co) polymer having a specific viscosity of at least? sp 0.7, which is obtained by polymerizing in emulsion of 99 to 50 parts by weight of a monomer mixture ( A) comprising from 51 to 100% by weight of methyl methacrylate, from 0 to 49% by weight of at least one monomer selected from the group consisting of a methacrylate ester except methyl methacrylate and an acrylate ester, and from 0 to 20% by weight of a copolymer vinyl monomer merizable with it, wherein the total amount of (A) and (B) is 100 parts by weight.

2. The processing aid according to claim 1, further characterized in that the processing aid for a vinyl chloride resin is a processing aid for a vinyl chloride resin containing a foaming agent.

3. - A vinyl chloride resin composition comprising 100 parts by weight of a vinyl chloride resin and from 0.1 to 30 parts by weight of the processing aid according to claim 1. 4.- A chloride resin composition of vinyl containing a foaming agent comprising 100 parts by weight of a vinyl chloride resin, from 0.1 to 30 parts by weight of the processing aid according to claim 1 and a foaming agent.