NL8005812A - PROCESS FOR PREPARING VINYL CHLORIDE RESINS BY SUSPENSION POLYMERIZATION. - Google Patents

Description

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Process for preparing vinyl chloride resins by slurry polymerization.

The invention relates to a process for preparing a polyvinyl chloride resin by suspension polymerization and more particularly to a process for preparing a polyvinyl chloride resin with excellent heat resistance as well as a remarkably reduced initial coloring in the formation to articles by suspension polymerization of the vinyl chloride monomer in an aqueous medium, the polymerization efficiency being remarkably improved due to the extremely reduced amount of the polymer crust build-up on the walls of the polymerization sation reactor.

It is well known that in most cases polyvinyl chloride resins are prepared by suspension polymerization of vinyl chloride monomer in an aqueous medium. One of the major technical difficulties in the suspension polymerization of vinyl chloride monomer in an aqueous polymerization medium is the polymer crust build-up on the walls of the polymerization reactor. In the suspension polymerization of vinyl chloride monomer in an aqueous medium contained in a polymerization reactor of stainless steel or other materials, polymer crust deposits occur on the interior walls of the reactor or on other surfaces that come in contact with the monomer, such as on the stirrer placed in the reactor, which not only results in a reduction in the polymer yield, but also in a decrease in the cooling capacity of the reactor, and consequently in a decrease in the total production capacity of the equipment. In addition, the polymer crust often detaches from the reactor walls and is incorporated into the resin product, resulting in lower product quality due to the increasing amount of so-called fish eyes in the manufacture of polyvinyl chloride resin articles. An equally great difficulty is that the removal of the polymer crust after each polymerization run requires a lot of labor and time, greatly reducing productivity as well as causing serious health problems for the operating personnel and due to the toxicity of the vinyl chloride-5 monomer, which is present in large amounts in the polymer crust.

On the other hand, it is also known in the art that some of the properties which determine the product quality of the polyvinyl chloride resins are influenced by different parameters during the polymerization reaction. For example, the heat resistance and initial coloring in the manufacture of articles from the resin are greatly affected by the nature of the polymerization initiator used in the polymerization reaction. As is well known, the polymerization initiators used in the suspension polymerization of vinyl chloride monomer are always monomer soluble polymerization initiators. These monomer soluble polymerization initiators are of course substantially insoluble or sparingly soluble in water, but it is noted that even these monomer soluble polymerization initiators have a water solubility, although the solubility can be very low. It has become known in the art that the solubility of the polymerization initiator in water is a parameter affecting the heat resistance and initial coloring of the poly-vinyl chloride resin products polymerized therewith, and in this regard an organic peroxide as initiator with a relatively high water solubility of, for example, 0.2 wt% or more at 20 ° C, beneficial in improving the heat resistance and initial coloring of the resin products as compared to an organic peroxide with less water solubility than indicated above.

Despite the above-described advantages with regard to the thermal resistance of the resin products polymerized therewith, such organic peroxides with relatively high water solubility are not generally used in practice in the technical preparation of polyvinyl chloride 8005812 * 4 3 resins. This is due in part to the undesirable fact that the use of such an organic peroxide results in much greater amounts of polymer crust deposition on the reactor walls than less water-soluble organic peroxides.

Of course, several attempts have been made to reduce the amount of polymer crust deposition in the suspension polymerization of vinyl chloride monomer in an aqueous medium, taking two approaches, namely, to provide the reactor walls with a coating of a material. which is less susceptible to the deposition of a polymer crust before carrying out the polymerization and adding certain specific additives to the reacted polymerization mixture.

As coating materials used in the first approach to the above attempts, there have been proposed, for example, polar organic compounds, organic dyes and pigments, including amine compounds, quinone compounds, aldehyde compounds and the like (see, for example, Japanese Patent Publications 45 -30343, 45-30835, etc.) »polar organic compounds or organic dyes, treated with a metal salt (see Japanese Patent Publication 52-24953), mixtures of an electron donor compound and an electron acceptor compound (see Japanese Patent Publication 53- 28347) and certain inorganic salts and inorganic complex compounds (see Japanese Patent Publication 52-24070).

The above-mentioned coating methods are very effective when the polymerization initiator used in the reaction is an azo compound or an organic peroxide with long chain alkyl groups, which polymerization initiators consequently have very low water solubility. Unfortunately, these methods are substantially ineffective at all in reducing polymer crust deposition when polymerization is performed using an organic peroxide of relatively high water solubility. Thus, no effective method has yet been developed for preventing polymer crust deposition in the polymerization of vinyl chloride monomer using an organic peroxide with a water solubility of 0.2% by weight. or greater as a polymerization initiator.

The object of the invention is therefore to provide a new and improved process for the preparation of a polyvinyl chloride resin with excellent heat resistance, ie thermal decomposition by heating and initial coloring in the formation of objects from the resin.

The invention further contemplates providing a new and improved process for the preparation of polyvinyl chloride resin having excellent thermal resistance as mentioned above by suspension polymerization of vinyl chloride monomer in an aqueous medium using a polymerization initiator, which is an organic peroxide with a water solubility of at least 0.2% by weight at 20 ° C.

The invention provides an improved method for the suspension polymerization of vinyl chloride monomer or a monomer mixture consisting essentially of vinyl chloride in an aqueous polymerization medium using a monomer soluble organic peroxide with a water solubility of at least 0. 2% by weight at 20 ° C as a polymerization initiator, which process is characterized in that (a) before the polymerization mixture is fed to the polymerization reactor, the inner walls of the polymerization reactor are coated with an aqueous coating solution containing an organic dye with a sulfonic acid group -SOH or carboxylic acid group -C00H in a molecule in the form of an alkali metal or ammonium salt or an alkali metal salt or ammonium salt of an organic sulfonic acid or carboxylic acid with at least one pair of conjugated double bonds in a molecule, followed by drying , and (b) a water-soluble thio-cyanate to the polymerization addition mixture in an amount of at least 1 ppm based on the amount of the monomer or monomers.

The suspension polymerization of vinyl chloride monomer according to the process of the invention is applicable not only to the homopolymerization of vinyl chloride monomer, but also to the copolymerization of vinyl chloride monomer with one or more copolymerizable ethylenically unsaturated monomers, provided that the main component that is, 50% by weight or more, is vinyl chloride. Examples of comonomers copolymerizable with vinyl chloride include vinyl esters such as vinyl acetate, vinyl propionate and the like, vinyl ethers, acrylic acid and methacrylic acids and esters thereof, acrylonitrile, vinyl ketones, vinylidene halides such as vinylidene chloride, vinylidene fluoride and the like, and olefins such as ethylene, propylene and the like.

The polymerization procedure is virtually conventional and the same as the one already known in the art except that the reactor walls are coated and the thio cyanate is added as mentioned above. For example, suitable dispersants used for the suspension of the monomer or monomer mixture in the aqueous medium include water-soluble synthetic and natural polymeric substances, such as fully or partially saponified polyvinyl alcohol, cellulose ethers, for example, methyl cellulose, hydroxypropyl - methyl cellulose and the like, polyacrylic acid, copolymers of vinyl acetate and maleic anhydride, gelatin and starch, nonionic surfactants such as sorbitan monolaurate, sorbitan trioleate and the like, and dispersing aids such as carboxymethyl cellulose and the like.

As mentioned above, the method of the invention is particularly applicable to the suspension polymerization of vinyl chloride in an aqueous medium, the polymerization initiator used being a monomer soluble organic peroxide having a water solubility of at least -30. 1st 0.2 wt% at 20 ° C, although no adverse effects are caused when the process of the invention is applied to the polymerization of vinyl chloride with a polymerization initiator which is an azo compound or an organic peroxide with greater solubility in water than indicated above.

Several examples of the above-mentioned relatively water-soluble organic peroxides are di-2- 8005812 6 ethoxyethyl peroxydicarbonate, bis-3-methoxybutylperoxydicarbonate and dibutoxyethylperoxydicarbonate, hereinafter referred to briefly as EEP, MC and BEP, respectively, although the applicability of the method according to the invention is not limited to these three initiators.

The coating solution, which is applied to the inner walls of the polymerization reactor, and, as necessary, to the surfaces of other sections, such as the agitator of the reactor, which comes into contact with the monomer or monomers during the polymerization, is prepared by dissolving the above alkali metal or ammonium salts of organic dyes or acids in water.

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For example, the organic dyes with a sulfonic acid or carboxylic acid group in the molecule in the form of an alkali metal salt or ammonium salt are C.I. Direct Yellow 1, C.I.

Acid Yellow 38, C.I. Acid Yellow 3, C.I. Reactive Yellow 3, C.I. Direct Orange 2, C.I. Direct Orange 10, C.I. Direct Red 1, C.I. Acid Red 2, C.I. Acid Red 18, C.I. Acid Red 52, C.I. Acid Red 73, C.I. Direct Red 186, C.I. Direct Red 92, C.I. Basic Red 2, 20 C.I. Direct Violet 1, C.I. Direct Violet 22, C.I. Basic Violet 10, C.I. Acid Violet 11, C.I. Acid Violet 78, C.I. "Mordant"

Violet 5, C.I. Direct Blue 6, C.I. Direct Blue 71, C.I. Direct Blue 106, C.I. Reactive Blue 2, C.I. Reactive Blue 4, C.I. Reactive Blue 18, C.I. Acid Blue 116, C.I. Acid Blue 158, C.I.

25 "Mordant" Blue 1, C.I. "Mordant" Black 1, C.I. "Mordant" Black 5, C.I. Acid Black 2, C.I. Direct Black 38, C.I. Solubilized Barrel Black 1, C.I. Fluorescent Brightening Agent 30, C.I. Fluorescent Brightening Agent 32, C.I. "Azoic" Brown 2 and the like.

The organic sulfonic acids or carboxylic acids with at least one pair of conjugated double bonds in a molecule, which are used as the solute in the coating solution in the form of an alkali metal or ammonium salt, are, for example, toluidines, α-naphthalenesulfonic acid, anthraquinone sulfonic acids, dodecylbenzene sulfonic acid, p-toluenesulfonic acid, abietic acid, isonicotinic acid, benzoic acid, phenylglycine, 3-hydroxy-2- 8005812 J * 7 naphthoic acid and the like.

The coating solution is prepared by dissolving one or more of the above organic dyes or organic sulfonic or carboxylic acids, all in the form of the 5 salts, in water. The concentration of the coating solution is not limited, provided that the coating can be carried out without discomfort in such a way that a suitable amount of coating is obtained on the reactor walls.

The coating solution prepared in the manner described above is usually more or less alkaline, but preferably the coating solution is used after adjusting the pH of the solution to a value of not greater than 7 by adding a small amount of a acidic after dissolving the salts of the organic dyes or organic sulfonic acids or carboxylic acids. Suitable acids include sulfuric, hydrochloric, phosphoric, nitric, carbonic, perchloric, molybdenoic, tungsten, formic, acetic, oxalic, lactic, maleic, glycolic, thioglycolic, phytic, and the like. It is convenient to add these acids to the coating solution as a pre-prepared aqueous solution.

The aqueous coating solution is applied to the inner walls of the polymerization reactor and other surfaces in contact with the monomer or monomers by an appropriate method, for example, by spraying, brushing and the like, and the surface thus coated is then thoroughly dried, if necessary by heating. Optionally, the surface to be coated with the coating solution can be pre-heated to a temperature of 40-100 ° C before applying the coating. In any case, the coated and dried surface can be washed with water if necessary.

The aqueous coating solution can be prepared, if desired, using a mixed solvent of water and a water-miscible organic solvent. In this way, the advantage is obtained that the drying of the coated surface is accelerated, so that in some cases no heating is required for the drying. Suitable organic solvents include alcoholic solvents, ester solvents and ketone solvents.

The coating amount with the coating solution is preferably such that the amount in dried form is at least 0.001 grams / m 2 on the coated surface, which amount is analogous to the amount used in the prior art coating methods for preventing of the poly-10 multi-crust deposit.

After the completion of the coating of the reactor walls in the manner described above, the polymerization reaction is started in the usual manner by adding water to the polymerization medium, dispersing or suspending agent, polymerization initiator and vinyl chloride monomer or monomers as well as other optional ingredients to form the polymerization mixture. It is essential that at least one type of water-soluble thiocyanates is added to the polymerization mixture.

The water-soluble thiocyanates suitable for use in the process of the invention are, for example, thiocyanates of an alkali metal such as sodium, potassium and cesium, ammonium thiocyanate and thiocyanates of alkaline earth metals such as magnesium, calcium, strontium and barium. These thiocyanates can be added directly to the polymerization mixture to dissolve in the aqueous medium, preferably before the polymerization is started, although about the same desirable effects can be obtained when the thiocyanate is added after the polymerization has started, but this addition should not be late.

The amount of thiocyanate added to the polymerization mixture is desirably at least 1 part by weight per million based on the amount of the vinyl chloride monomer or monomer mixture. The upper limit of the amount of thio-cyanate is 500 parts per million or preferably 100 parts per million, based on the monomer or monomer mixture. This upper limit is determined by the adverse effects on the quality of the resin products with an excessive amount of the thiocyanate, while no particular further effects can be obtained in preventing the polymer crust deposit.

Although the process of the invention is applicable to the suspension polymerization of vinyl chloride with an organic peroxide initiator, not only with a water solubility of at least 0.2% by weight, but also with a water solubility of less than 0 2 wt.% At 20 ° C, it will be appreciated that the organic peroxide cannot have excessively high water solubility, because the polymerization in such a mixture containing an excessive amount of water-soluble organic peroxide initiator proceeds approximately as an emulsion polymerization, whereby the desired suspension polymerisate of the polyvinyl chloride resin is not obtained. In this regard, it is noted that the polymerization according to the invention must be carried out using an organic peroxide as a polymerization initiator with a water solubility of no greater than 20 wt% or preferably no greater than 5 wt% at 20 ° C.

The invention is further illustrated but not limited by the following examples.

Example I (Tests 1-29)

Four series of polymerization runs were conducted, each using seven kinds of monomer soluble organic peroxides as a polymerization initiator. The organic peroxides were di-2-ethylhexyl peroxydicarbonate, lauroyl peroxide, 3.5.5-trimethylhexanoyl peroxide and α-cumyl peroxyneodecanoate, hereinafter referred to briefly as OPP, LPO, 30 L-355 and L-188, respectively, in addition to the above peroxides EEP, MC and BEP.

The solubility of these peroxides in water was determined by dispersing an excess amount of each of the peroxides in water at 20 ° C and, after equilibrium adjustment, titrating the aqueous solution iodometrically, obtaining centrifugal separation of the dispersion. The results were: OPP 0.04 wt%, LPO 0.003 wt%, L-355 0.05 wt%, L-188 8005812 10 0.01 wt%, EEP 0.41 wt%, MC 0 , 24 wt% and BEP 0.20 wt%.

The following procedure was used for each of the polymerization runs. First, three kinds of coating solutions were prepared with the compositions indicated below, and the inner walls of a 1000 liter capacity polymerization reactor made of stainless steel, and the surface of the stirrer, placed in the reactor, were coated with one of the coating solutions, after which the coated surfaces were dried by heating at 90 ° C for 10 minutes. The compositions of the coating solutions are indicated below.

Coating Solution A: 0.1% by weight methyl alcohol solution of C.I. Solvent Black 7;

Coating solution B: 0.1 wt% methyl alcohol solution of sodium thiocyanate, and

Coating Solution C: 0.1 wt% aqueous solution of C.I.

Acid Black 2 with a pH of 3.0, adjusted by adding sulfuric acid.

The coating amount with each of the coating solutions was 0.1 g / m after drying.

500 kg of water containing 150 g of a partially saponified polyvinyl alcohol, one of the above organic peroxides in an amount of 500 g for LP0 or 100, were introduced into the polymerization reactor, the surface of which had been treated as described above. g for each of the other peroxides and 250 kg of vinyl chloride monomer, with or without addition of 2.5 g of ammonium thiocyanate, and the polymerization was carried out by heating at 50 ° C for 10 hours in the usual manner. After the completion of the polymerization reaction, the polymerizate slurry was discharged from the polymerization reactor and the amount of polymer crust deposited on the reactor walls was examined to give the results shown in Table A below. For comparison, a further polymerization was carried out without a coating treatment of the reactor walls, and the results obtained thereby are also shown in Table A below.

8005812 2 11

Table A

___ (Polymeric crust deposit g / m) ______

Coating Ammonium - Organic Peroxide -

solution thiocyanate OPP LPO L-355 L-188 EEP MC BEP

5 A_la_1 2 1 3 450 400 250 B_ja_12 18 25 33 550 600 320 C_ja_1 2 1 4 0 0 0 C_neen_1 3 3 8 300 100 85

No no-_-_ 1500 _- 10 From the results shown in Table A, of which the experiments, initiated by EEP, MC or BEP, and with the coating solution C for the coating treatment and the addition of ammonium thiocyanate examples of the invention appears

that the polymer crust deposit upon polymerization with EEP, MC

15 or BEP can be almost completely eliminated only when the two measures of coating and addition of thiocyanate are taken according to the method of the invention.

Example II (Trials 30-41)

Aqueous coating solutions were prepared by each dissolving one of the coating compounds, indicated in Table B below, at a concentration of 1 wt% with a subsequent adjustment of the pH to 4.0 by addition of acetic acid. The inner walls of a 1000 liter capacity polymerization reactor made of stainless steel, and the surface of the stirrer placed in the reactor were coated with one of the coating solutions in a coating amount of 0.1 g / m in dry form, followed by drying by heating at 90 ° C for 10 minutes and washing with water.

400 kg of water, 250 g of a partially saponified polyvinyl alcohol, 25 g of hydroxypropylmethylcellulose, 75 g of EEP and 200 kg of vinyl chloride monomer with or without addition of ammonium thiocyanate in an amount as indicated in Table B were introduced into the polymerization reactor thus treated. the polymerization was carried out by heating the polymerization mixture at 57 ° C for 12 hours.

After the completion of the polymerization reactor, the polymerisate slurry was discharged from the reactor and the amount of the polymer crust deposit on the reactor walls was examined to give the results shown in Table B below. Also, the dried polyvinyl chloride-5 resin product obtained in each of the polymerization tests was tested for the amount of fish eyes and the heat resistance using the test procedures described below, yielding the results also shown in Table B below. The heat resistance of the resin product obtained in the last run was somewhat inferior to that obtained in the other polymerization runs, showing that an excessive amount of the thiocyanate is disadvantageous in the heat resistance of the resin product.

Fish-eye test: A resin mixture consisting of 100 parts by weight of the resin product, 50 parts by weight of dioctyl phthalate, 1 part by weight of dibutyltin dilaurate, 1 part by weight of cetyl alcohol, 0.25 part by weight of titanium dioxide and 0.05 part by weight .dl of carbon black was kneaded in a two-roll mill at 150 ° C for 7 minutes and then formed into a sheet with a thickness of 0.2 mm, the number of fish eye pieces of which were counted per 100 cm area of the sheet under illumination with transmitted light.

Heat resistance test: A resin mixture consisting of 100 parts by weight of the resin product, 1 part by weight of stearic acid and 1 part by weight of dibutyltin maleate was kneaded in a two-roll mill at 170 ° C at a rolling distance of 0.7 mm for 10 minutes and then formed into a sheet with a thickness of 0.7 mm. The samples taken from this sheet were heated in a Geer's oven at 180 ° C and the time in minutes until the sample turned black was taken as a measure of the heat resistance of the resin product. 30 8005812 13

Table B

Coating Added Fish Eyes Heat Polymeric Crust Compound Ammonium (Pieces) Resistant Deposition Thiocyanate (g / m2) 5 (parts (minutes) per million Monomer) ____

None None 60 120 1600

None 10 55 120 1500 10 C.I. Acid Blue 116 None 40 120 350 C.I. Acid Blue 116 10 8 120 0

Ammoniumabietate 10 10 120 3

Sodium a-naphthalene sulfonate 10 10 120 2 15 C.I. Straight away

Blue 6 20 6 120 0 C.I. Acid Violet 78 1 10 120 3 C.I. Acid Violet 78 10 6 120 1 C.I. Acid Violet 78 50 4 120 0 20 C.I. Acid Violet 78 100 4 120 0 C.I. Acid Violet 78 1000 4 80 0 ___ I_ | _

Example III (Tests 42-48)

Aqueous coating solutions were prepared by dissolving one of the coating compounds, indicated in Table C below, at a concentration of 1% by weight, followed by adjusting the pH to 2.5 by adding phosphoric acid. The inner walls of a 100 liter capacity polymerization reactor made of stainless steel and the surface of the stirrer placed in the reactor were coated with one of the coating solutions thus prepared at a coating amount of 0.1 g / m in dried form, followed by drying by heating at 90 ° C for 10 minutes and washing with water.

35 kg of water, 17 kg of vinyl chloride monomer, 3 kg of vinyl acetate monomer, 12 g of a partially saponified polyvinyl alcohol, 4 g of a hydroxypropylmethylcellulose, 6 g of MC and 200 g of 8005812 were introduced into the polymerization reactor thus coated. 14 trichlorethylene with or without addition of a thiocyanate of the kind and in the amount indicated in Table C and, after 15 minutes of prior stirring, the polymerization was carried out by heating the polymerization mixture at a temperature of 58 ° C for 12 hours.

After the completion of the polymerization reaction, the polymerizate slurry was discharged from the polymerization reactor and the amounts of polymer crust deposition on the reactor walls were determined to yield the results shown in Table C.

Table C

Coating Added thiocyanate Polymeric crust compound (g ppm monomer) deposit (g / in)

None None 1800 15 None Ammonium thiocyanate (10) 1600 C.I. Acid Black 2 None 1300 C.I. Acid Black 2 Ammonium Thiocyanate (10) 3 C.I. Acid Red 2 Sodium Thiocyanate (20) 2 C.I. Acid Yellow 38 Calcium Thiocyanate (20) 1 20 C.I. Direct Red 1 Potassium Thiocyanate (10) 1 8005812

Claims (8)

A process for preparing a polyvinyl chloride resin by suspension polymerization of vinyl chloride-monomer or a monomer mixture consisting essentially of vinyl-5 chloride monomer in an aqueous polymerization medium containing a suspending agent and a monomer-soluble polymerization initiator, which is an organic peroxide with a solubility in water of at least 0.2 wt.% at 20 ° C, in a polymerization reactor, characterized in that (a) before the polymerization, the inner walls of the polymerization reactor are coated with an aqueous coating solution containing at least one of the substances dissolved therein, selected from organic dyes having at least one sulfonic acid group or carboxylic acid group in the molecule in the form of an alkali metal salt or ammonium salt and alkali metal salts or ammonium salts of organic sulfonic acids and carboxylic acids with at least one pair of conjugated double bonds in the molecule, followed by drying, and (b) at least add one water-soluble thiocyanate to the polymerization mixture in the polymerization reactor. A method according to claim 1, characterized in that the aqueous coating solution has a pH value of no greater than 7 by adding an acid. 3. Process according to claim 1, characterized in that the coating amount of the inner walls of the polymerization reactor with the aqueous coating solution is at least 0.001 g / m in dried form. 4. Process according to claim 1, characterized in that the water-soluble thiocyanate is selected from thiocyanates of alkali metals, ammonium thiocyanate and thiocyanates of alkaline earth metals. 5. Process according to claim 1, characterized in that the water-soluble thiocyanate is added to the polymerization mixture in an amount of 1-500 parts by weight per million, based on the vinyl chloride monomer or the monomer mixture. The method of claim 1, characterized in 8005812 that the organic dye is selected from C.I. Direct Yellow 1, C.I. Acid Yellow 38, C.I. Acid Orange 2, C.I. Direct Orange 10, C.I. Direct Red 1, C.I. Acid Red 2, C.I. Acid Red 18, C.I. Acid Red 52, C.I. Acid Red 73, C.I. Direct Red 186, C.I. Direct Red 5 92, C.I. Basic Red 2, C.I. Direct Violet 1, C.I. Direct Violet 22, C.I. Basic Violet 10, C.I. Acid Violet 11, C.I. Acid Violet 78, C.I. "Mordant” Violet 5, C.I. Direct Blue 6, C.I. Direct Blue 71, C.I. Direct Blue 106, C.I. Reactive Blue 2, C.I. Reactive Blue 4, C.I. Reactive Blue 18, C.I Acid Blue 116, 10 C.I. Acid Blue 158, C.I. "Mordant" Black 1, C.I. "Mordant" Black 5, C.I. Acid Black 2, C.I. Direct Black 38, C.I. Solubilized Barrel Black 1, C.I. Fluorescent Heidennakend Middel 30, C.I. Fluorescent Brightening Agent 32 and C.I. "Azoic" Brown 2 and the organic sulfonic or carboxylic acid with at least one pair of conjugated double bonds in the molecule is selected from toluidine, α-naphthalene sulfonic acid, anthraquinone sulfonic acids, dodecylbenzene sulfonic acids, p-toluenesulfonic acid, abietic acid, isonicotinic acid, benzoic acid hydroxy-2-naphthoic acid. 7. Articles made in whole or in part from the polyvinyl chloride resin prepared according to claims 1-6. 8. Methods and articles as described in the description and / or examples. 8005812 "-Λ