NZ227704A - Polymeric water-service pipe with a lead containing stabiliser - Google Patents

Description

•I 22 7 No.: Date: Priority Date(s): CompSete Specification Filed."?i^-i .1.'.^.' class: Rite.waastf Publication Date: .. .QPP. M? P.O. Journal, No: ... A35C?.- NEW ZEALAND PATENTS ACT, 1953 COMPLETE SPECIFICATION "WATER SERVICE PIPE AND ADDITIVE FOR PRODUCTION THEREOF" I /we, MIZUSAWA INDUSTRIAL CHEMICALS, LTD, a Japanese company of. 1-21 Muromachi 4-chome, Nihonbashi, Chuo-ku, Tokyo, Japan hereby declare the invention for which I / we pray that a patent may be granted to me/us, and the method by which it is to be performed, to be particularly described in and by the following statement: - (followed by page la) 22 7 7 0 4 WATER SERVICE PIPE AND ADDITIVE FOR PRODUCTION THEREOF Background of the Invention (1) Field of the Invention The present invention relates to a water service pipe composed of a chlorine-containing polymer composition and also to an additive for use in the production thereof. More particularly, the present invention relates to a water service pipe in which elusion of lead is controlled and also to an additive for use in the production thereof. (2) Description of the Related Art A chlorine-containing polymer, for example, a vinyl chloride resin, undergoes dehydrochlorination in the molecule chain when exposed to heat or light, resulting in decomposition, discoloration and deterioration. The decomposition reaction by dehydrochlorination is a self-catalytic reaction in which formed hydrogen chloride acts as a catalyst. Accordingly, various stabilizers or stabilizer compositions for catching this hydrogen chloride and heat-stabilizing the vinyl chloride resin have been proposed.

As the heat stabilizer f'or pipes, a lead salt of a fatty acid and a tribasic lead salt have been, used, and it is known that these lead type stabilizers are especially excellent in the heat-stabilizing effect. However, a vinyl chloride resin pipe in which such a lead type stabilizer is incorporated involves a problem in that lead is dissolved out in water at a concentration of scores of ppb to several hundred ppb at the start of the use.

We previously proposed in Japanese Patent Publication No. 12939/83 that a zeolite of the type A, optionally with a lead salt of a fatty acid, a basic 22 7 7 0 4 n o. lead salt or* other inorganic stabilizer, is incorporated into a chlorine-containing polymer. Furthermore, in Japanese Patent Application Laid-Open Specification No. 14204-3/83, it is taught that if a zeolite of the type A 5 and a lead type stabilizer are incorporated in a vinyl chloride resin, elusion of lead is controlled.

In the production of molded articles such as pipes, a filler is ordinarily incorporated in a resin composition for attaining a bulking effect, improving 10 the moldability and adjusting the strength or hardness. In the production of a pipe of a chlorine-containing polymer, a calcium carbonate filler is most preferred in view of the dispersibility in the resin, the auxiliary stabilizing effect and the price.

However, it was found that if a calcium carbonate filler is incorporated together with a lead type stabilizer such as a lead salt of a fatty acid or a basic lead salt into a chlorine-containing polymer, elusion of lead from a formed service water pipe is much larger 20 than in case of a calcium carbonate-free pipe.

Summary of the Invention It is therefore a primary object of the present invention to effectively control elusion of lead in a water service pipe composed of a chlorine-containing 25 polymer composition in which a lead type stabilizer and a calcium carbonate filler are incorporated.

Another object of the present invention is to provide a water service pipe of a chlorine-containing polymer which has a controlled elusion quantity of lead, 30 an excellent heat stability, a high strength and an excellent appearance in combination.

In accordance with one aspect of the present invention, there is provided a water service pipe which is composed of a resin composition comprising 100 parts 35 by weight of a chlorine-containing polymer, 0.1 to 5.0 22 7 7 0 4 n P.! parts by weight of a lead type stabilizer comprising a lead salt of a fatty acid, a combination of a lead salt of a fatty acid and a basic lead salt, a combination of a lead salt of a fatty acid and a tin type stabilizer or 5 a combination of a lead salt of a fatty acid and a metal soap type stabilizer, 0.01 to 15 parts by weight of a calcium carbonate filler, up to 5-0 parts by weight of a lubricant and 0.01 to 3.0 parts by weight of a zeolite of the type A.

It is preferred that in the zeolite of the type A used in the present invention, the hydrogen chloride capture quantity (C) defined as the quantity of hydrochloric acid necessary for reducing the pH value of the zeolite to 5 from 9 by using a 0.4N aqueous solution 15 of hydrochloric acid be at least 3 mj2/g.

In accordance with another aspect of the present invention, there is provided a one-package additive for a chlorine-containing polymer, which comprises (i) a lead type stabilizer comprising a lead salt of a fatty acid, 20 a combination of a lead salt of a fatty acid and a basic lead salt, a combination of a lead salt of a fatty acid ^ and a tin type stabilizer or a combination of a lead / r"1 salt of a fatty acid and a metal soap type stabilizer, (ii) a calcium carbonate filler, (iii) a lubricant and 25 (iv) a zeolite of the type A, said components (i) through (iv) being mixed so that the amounts of the components (i) through (iv) are 0.1 to 5 parts by weight, 0.01 to 15 parts by weight, up to 5 parts by weight and 0.01 to 3 parts by weight, respectively, per 100 parts 30 by weight of the chlorine-containing polymer.

In accordance with still another aspect of the present invention, there is provided a stabilizer for a chlorine-containing polymer, which comprises sodium aluminosilicate or calcium aluminosilicate having an X-35 ray diffraction pattern inherent to a zeolite of the 22 7 7 0 4 type A or a mixture thereof, wherein the hydrogen chloride capture quantity (C) defined as the quantity of hydrochloric acid necessary for reducing the pH value of the zeolite to 5 from 9 by using a 0.4N aqueous solution of hydrochloric acid is at least 3 m^/g, the maximum reduction gradient (Rmax) determined from the tangential line of the maximum gradient portion of the hydrochloric acid titration curve is -0.1 to -0.7 pH/meq HCjZ. per 100 g of the zeolite, and the maintenance pH reduction gradient (Rmain) determined from the tangential line of the subsequent small-inclination portion of the hydrochloric acid titration curve is -0.001 to -0.07 pH/meq HC-£ per 100 g of the zeolite.

Brief Description of the Drawings Fig. 1 is a diagram illustrating the elusion quantity of lead from a water service pipe composed of rigid polyvinyl chloride containing, incorporated therein, a lead type stabilizer and calcium carbonate, in which a zeolite of the type A is incorporated or not incorporated. In Fig. 1, A-l illustrates the results of Runs 2, 15, 16 and 17 according to the present invention, A-2 illustrates the results of Runs 18, 19, 20 and 21 according to the present invention, B-l illustrates Runs 26, 27, 28 and 29 as comparative runs, and B-2 illustrates the results of runs 30, 31, 32 and 33 as comparative runs.

Fig. 2 shows a hydrochloric acid titration curve of an aqueous dispersion of the zeolite of the type A used in the present invention. In Fig. 2, C-l, C-2, C-3, C-4 and C-5 are curves of zeolite A samples NA-21, NA-11, CA-12, CA-22 and CA-23 obtained in Examples 1 and 2.

Detailed Description of the Invention The present invention is based on the novel finding that if a zeolite, is incorporated in a chlorine-containing polymer composition containing a lead type 22 7 7 04 stabilizer and a calcium carbonate filler, elusion of lead from a pipe formed of this composition is prominently controlled.

Curve B in Fig. 1 of the accompanying drawings shows the relation between the amount incorporated of calcium carbonate and the initial elusion quantity of lead from a pipe formed of a composition comprising 100 parts by weight of a vinyl chloride resin, 1.8 parts by weight of a lead type stabilizer (lead stearate) and a variable amount of calcium carbonate. From the results of curve B of Fig. 1, it is seen that with increase of the quantity of calcium carbonate incorporated as the filler, the initial elusion quantity of lead from the pipe drastically increases.

On the other hand, curve A in Fig. 1 shows the relation between the amount incorporated of calcium carbonate and the initial elusion quantity of lead from a pipe formed of the above composition in which a zeolite A of the Na type (Mizukariser® DS) is further incorporated in an amount of 0.5 part by weight. If curve A is compared with curve B in Fig. 1, it is understood that by incorporating a zeolite of the type A, even if the amount incorporated of calcium carbonate is increased, the elusion quantity of lead from the pipe is controlled to a very low level.

The reasons why the elusion quantity of lead increases with increase of calcium carbonate in the composition of the above-mentioned system and the elusion quantity of lead is controlled to a low level even in case of incorporation of calcium carbonate by addition of a zeolite of the type A have not sufficiently been elucidated. However, we presume that the reasons will probably be as follows.

It is believed that elusion of lead from the pipe is not elusion of the used lead type stabilizer per se 22 7 7 but is elusion of lead chloride formed by reaction with hydrogen chloride formed by the decomposition of the chlorine-containing polymer. In a chlorine-containing polymer in which calcium carbonate and a lead type 5 stabilizer are incorporated, calcium chloride is formed at the melt-molding step. Since calcium chloride has a strong water-absorbing property, it is believed that lead chloride simultaneously formed by this reaction or lead chloride formed by ion exchange with calcium 10 chloride is dissolved out from the surface of the pipe. In the case where a zeolite of the type A is incorporated, reaction between hydrogen chloride and the zeolite A is preferentially advanced while reaction between calcium carbonate and hydrogen chloride is 15 inhibited, and therefore, formation of calcium chloride having a high water-absorbing property is controlled, with the result that elusion of lead is drastically reduced.

From the foregoing viewpoint, it is preferred that 20 the above-mentioned hydrogen chloride capture quantity (C) of the zeolite A used in the present invention be at least 3 m^/g, especially 5 to 10 mj2/g.

Incidentally, the hydrogen chloride capture quantity (C) is defined as the quantity of hydrochloric 25 acid necessary for reducing the pH value to 5 from 9 in the present invention. The reason is that it is considered that this pH range is effective for the actual capture of hydrogen chloride, the enhancement of the heat stability and the control of the elusion of lead. 30 More specifically, if the pH value is higher than 9, the zeolite A tends to cause initial coloration of the chlorine-containing polymer, and if the pH value is lower than 5, the capture of hydrogen chloride is not preferentially effected. Therefore, it is construed 35 that the above-mentioned pH range is preferred for 22 7 7 0 4 n <C\ t ' . defining the zeolite A.

As the chlorine-containing polymer, there can be optionally used known chlorine-containing resins, for example, polyvinyl chloride, vinyl chloride copolymers 5 such as a vinyl chloride/vinyl acetate copolymer, a vinyl chloride/ethylene copolymer, a vinyl chloride/propylene copolymer, a vinyl chloride/styrene copolymer, a vinyl chloride/isobutylene copolymer, a vinyl chloride/vinylidene chloride copolymer, a vinyl 10 chloride/styrene/maleic anhydride copolymer, a vinyl chloride/styrene/acrylonitrile copolymer, a vinyl chloride/butadiene copolymer, a vinyl chloride/isoprene copolymer, a vinyl chloride/chlorinated propylene copolymer, a vinyl chloride/vinylidene chloride/vinyl 15 acetate copolymer, a vinyl chloride/acrylic acid ester copolymer, a vinyl chloride/maleic acid ester copolymer and a vinyl chloride/methacrylic acid ester copolymer, vinylidene chloride resins, chlorinated polyethylene, chlorinated polyvinyl chloride, chloroprene rubber, and 20 chlorinated polychloroprene. Furthermore, there can be used blends of these chlorine-containing resins with o(-olefin polymers such as polyethylene, polypropylene, polybutene and poly-3-methylbutene, polyolefins such as an ethylene/vinyl acetate copolymer and an 25 ethylene/propylene copolymer, copolymers thereof, polystyrene, acrylic resins, copolymers of styrene with other monomers (for example, maleic anhydride butadiene and acrylonitrile), an acrylonitrile/butadiene/styrene copolymer, an acrylic acid ester/butadiene/styrene 30 copolymer and a methacrylic acid ester/butadiene/styrene copolymer, and chlorine-containing rubbers.

The lead type stabilizer is an indispensable component for imparting a high heat stability required for a water service pipe. As the lead type stabilizer, 35 there can be used a lead salt of a fatty acid, a a 227704 combination of a lead salt of a fatty acid and a basic lead salt, a combination of a lead salt of a fatty acid and a tin type stabilizer, and a combination of a lead salt of a D fatty acid and a metal soap type stabilizer. The lead salt of the fatty acid exerts not only a heat stabilizing action but also a lubricating action and is able to increase the effective lead content to a relatively high level while maintaining a good balance among functions CJ) of the respective ingredients. Therefore, the lead salt of the fatty acid is used as the lead type stabilizer in the present invention.

As the lead salt of the fatty acid, there can be mentioned lead salts of higher fatty acids, especially saturated and unsaturated fatty acids having 8 to 22 15 carbon atoms, such as lauric acid, palmitic acid, stearic acid, octadeconoic acid, oleic acid, linoleic acid and ricinoleic acid, and lead salts of branched fatty acids such as oxo process carboxylic acids and neo acids, especially carboxylic acids represented by the 20 following formula: fr\ G R1-C-COOH R, wherein R^ stands for a long-chain alkyl group, especially an alkyl group having 6 to 20 carbon atoms, R£ stands for a lower alkyl group, especially an alkyl group having up to 6 carbon atoms, and R^ stands for a hydrogen atom or a lower alkyl group N .r-~—_ such as 2-ethylene-hexonic acid, isodecanoic acid, 9 22770 isododecanoic acid, isotetradodecanoic acid, neodecanoic acid and neotetradodecanoic acid.

As the basic lead salt, there can be mentioned tribasic lead sulfate, tetrabasic lead sulfate, dibasic lead phosphite, basic lead carbonate, basic lead sulfite, basic lead silicate, basic lead phthalate and basic lead maleate.

The tin type stabilizer can be used in combination with the lead type stabilizer for improving the weatherability. A tin maleate type stabilizer or tin laurate type stabilizer having no risk of contamination can be used as the tin type stabilizer.

The metal soap type stabilizer can be effectively used in combination with the lead type stabilizer for adjusting gelation and imparting a heat resistance.

It is preferred that the lead type stabilizer be used in an amount of 0.1 to 5 parts by weight, especially 0.3 to 2.5 parts by weight, per 100 parts by weight of the chlorine-containing polymer. if the amount of the lead type stabilizer is too small and below the above-mentioned range, the heat stability of the pipe is insufficient. If the amount of the lead type stabilizer is too large and exceeds the above-mentioned range, control of the elusion of lead becomes insufficient, and use of such a large amount of the lead type stabilizer is not preferred from the economical viewpoint.

In view of the moldability into a pipe, it is preferred that the weight ratio of the basic lead salt to the lead salt of the fatty acid be lower than 1, especially lower than 0.5.

In order to attain a bulking effect at the molding step, improve the pipe moldability, adjust the strength and hardness and attain an auxiliary heat stabilizing effect, calcium carbonate is i ----- *i chlorine-containing polymer. r, n ,o. 22 7 7 04 there can be used light calcium carbonate, heavy calcium carbonate, gluey calcium carbonate and a mixture thereof. In view of the dispersibility, calcium carbonate having the surface coated with a metal soap or 5 resin soap is advantageously used.

It is preferred that calcium carbonate be used in an amount of 0.01 to 15 parts by weight, especially 0.5 to 10 parts by weight, per 100 parts by weight of the chlorine-containing polymer. If the amount of calcium 10 carbonate is too small and below the above-mentioned range, the above-mentioned improvements by incorporation of the filler cannot be attained. If the amount of calcium carbonate exceeds the above-mentioned range, no satisfactory results can be obtained with respect to 15 control of elusion of lead or increase of the pipe strength.

In order to improve the pipe moldability, it is generally preferred that a lubricant be incorporated. As the lubricant, there can be used paraffin, 20 chlorinated paraffin, polyethylene wax, polypropylene wax, oxidized polyethylene wax, microcrystalline wax, montan wax, higher fatty acids, fatty acid amides, higher alcohols, higher fatty acid mono- and di-ester waxes, triglycerides, and metal soaps. It is preferred 25 that the lubricant be used in an amount of up to 5.0 parts by weight, especially 0.01 to 2.0 parts by weight, per 100 parts by weight of the chlorine-containing polymer.

The zeolite A to be used in the present invention, 30 for example, the zeolite A of the Na type, has the following chemical composition. o 22 7 7 r*.

Chemical Composition General Range Preferred Range Si02 35 to 45% 36 to 40% Aj^203 25 to 35% 27 to 33% Na20 13 to 20% 14 to 19% ignition loss 1 to 18% 15 to 17% Fe20^ below 3% below 1% CaO below 3% below 0.1% MgO below 3% below 0.1% This alkali metal aluminosilicate has ideally a composition represented by the formula of Na12(AJ2-12Si12°48^'1'5-30H20, and the sodium component in the left portion of the formula is the portion capable of 15 catching hydrogen chloride.

This zeolite of the type A has, in general, an X-ray diffraction pattern shown below.

X-Ray Diffraction Pattern 20 Spacing d (KX) Relative Intensity (I/In) 12.440 65.3 8.750 58.5 7.132 48.3 .5345 41.6 4.3708 17.8 4.1106 60 3.720 95.8 3-421 33 3.2995 81.4 2.9857 100 2.9098 24.6 2.7526 27.2 2.6270 70.4 2.5125 13.6 2.4661 11.0 22 7 7 04 It is preferred that the X-ray diffraction pattern of the alkali metal aluminosilicate be substantially the same as the X-ray diffraction pattern shown above, but according to the kind of the process for the synthesis of the alkali metal aluminosilicate, the relative intensity of each diffraction peak differs to some extent, namely within +.30%, especially within ±2.0%. Of course, an alkali metal aluminosilicate having such an X-ray diffraction pattern can also be advantageously used for attaining the objects of the present invention.

As pointed out hereinbefore, this zeolite A has a hydrogen chloride capture quantity (C) of at least 3 m X/g, especially 5 to 10 mJl/g.

The zeolite A used in the present invention has such a characteristic that the zeolite catches hydrogen chloride preferentially to calcium carbonate. However, even if calcium carbonate reacts with hydrogen chloride and calcium carbonate is formed, since the zeolite of the type A used in the present invention has a high ion exchange capacity to calcium chloride, the presence of residual calcium chloride is avoided. The ion exchange capacity of the zeolite A to calcium chloride is at least 2.1 meq/g, especially at least 3-0 meq/g.

A sodium type is most preferable for the zeolite A used in the present invention. However, up to 70 mole#, especially up to 60 mole#, of Na20 may be substituted by a polyvalent metal such as calcium, magnesium or zinc.

It is preferred that the zeolite of the type A used in the present invention should have a hydrochloric acid titration curve as shown in Fig. 2. In Fig. 2, the titration amount (milliequivalents) of HC^ per 100 g of the anhydrous zeolite is plotted on the abscissa, and the pH value of the system is plotted on the ordinate. From Fig. 2, it is seen that the titration curve of the p n /-T- zeolite preferably used in the present invention has a large-inclination portion at the initial stage of the titration and a subsequent small-inclination portion, that is, a portion of a small reduction of the pH value. More specifically, the zeolite of the type A preferably used in the present invention is characterized in that the maximum pH reduction gradient (Rmax) determined from the tangential line of the maximum gradient portion in the titration curve of Fig. 2 is generally -0.1 to -0.7 pH/meq HCJL per 100 g of the zeolite especially -0.2 to -0.5 pH/meq HC£ per 100 g of the zeolite, and the maintenance pH reduction gradient (Rmain) determined from the tangential line of the subsequent small-inclination portion of the titration curve is generally -0.001 to -0.07 pH/meq HCL per 100 g of the zeolite, especially -0.005 to -0.04 pH/meq HC£ per 100 g of the zeolite.

In the zeolite of the type A used in the present invention, it is construed that it is the alkali metal or alkaline earth metal component corresponding to the maximum pH reduction gradient (Rmax) portion that is effective for prevention of elusion of lead from the chlorine-containing polymer (prompt capture of hydrogen chloride). It also is construed that it is the alkali metal or alkaline earth metal component corresponding to the maintenance pH reduction gradient (Rmain) that is effective for heat-stabilizing the pipe of the chlorine-containing polymer.

The zeolite of the type A having such titration characteristics can be obtained according to methods described in the examples given hereinafter.

In the zeolite of the type A, it is preferred that the primary particle size (particle size determined from an electron micrQScope photograph) be smaller than 10 microns, especially smaller than 5 microns, and the 22 7 7 0 4 secondary particle size (determined by the sedimentation method) be smaller than 20^um, especially smaller than 10 ^um.

It is preferred that the zeolite A be incorporated in an amount of 0.01 to 3.0 parts by weight, especially 0.2 to 1.5 parts by weight, per 100 parts by weight of the chlorine-containing polymer. If the amount of the zeolite is too small and below the above-mentioned range, the effect of controlling the elusion of lead in the presence of calcium carbonate is not sufficient, and if the amount of the zeolite A is too large and exceeds the above-mentioned range, initial coloration is often caused in the molded resin article.

A pigment and other known additives can be incorporated in the chlorine-containing polymer composition of the present invention in addition to the above-mentioned ingredients.

The resulting composition is supplied to a hopper of a melt-kneading extruder and melt-kneaded, and if necessary deaeration is effected, and the melt is extrusion-molded through an annular die or a sizer to obtain a pipe. The melt-kneading temperature is changed according to the kind of the resin, but it is generally preferred that the melt-kneading temperature be 160 to 210*C.

The present invention will now be described in detail with reference to the following examples that by no means limit the scope of the invention.

The methods adopted for determining various characteristics in the examples are described below. (1) Na20 and CaO Contents (% by weight) A sample dried at 110*0 for 4 hours was subjected to the chemical analysis and an atomic absorption spectrometer was.^used for the determination. (2) Water Content {% by weight) 22 7 7 A sample was heat-treated at 850*C for 30 minutes and the decrease of the weight was measured as the ignition loss. (3) Average Particle Size (/*■) The average particle size was measured by a Coulter Counter, Model TA-II, by using a 50-ja aperture tube. (4) Hydrogen Chloride Capture Quantity (mj£/g) A 0.4N aqueous solution of hydrochloric acid was added with stirring at a rate of 0.6 m£/min to an aqueous suspension of a zeolite of the type A having a concentration of 3 g/100 m£, and the quantity of hydrochloric acid consumed for reducing the pH value to 5 from 9 was measured as the hydrogen chloride capture quantity. (5) Smoothness of Inner Surface of Pipe The concavities and convexities of the inner surface of the pipe and the roughness of the inner surface of the pipe were observed with the naked eye, and the smoothness was evaluated according to the following scale.

A: Small concavities and convexities, and reduced surface roughness B: small concavities and convexities, certain surface roughness C: prominent concavities and convexities (6) Heat Stability (min) A pipe piece was placed in a gear oven maintained at 190*C, and the change of the degree of heat coloration was examined with the lapse of time (at intervals of 5 minutes). The time when the gray color was changed to the brown color was measured, and the heat stability was evaluated by this time (min). (7) Lead Elusion Quantity (ppb) According tou the method of JIS K-6724, a sample pipe was washed with city water (30 m/min) for 1 hour 16 - 22 7 7 0 4 and test water (calcium content = 12 ppm, free residual chlorine content = 1.0 to 1.2 ppm, pH = 7.0 _+ 0.2) was sealed in the sample pipe and the pipe was allowed to stand still for 24 hours. Then, the amount of lead dissolved out into the test water was measured according to the dithizone method.

Example 1 This example illustrates the effect of controlling the elusion of lead by incorporating a zeolite of the type A in a water service pipe of a rigid polyvinyl chloride composition containing a lead type stabilizer and a calcium carbonate filler.

Preparation of Zeolite of Type A The zeolite of the type A used in this example was prepared in the following manner.

As the starting Si02 material, a finely divided silicate having the particle size distribution and chemical composition shown in Table 1, which was obtained by acid-treating acid clay produced at Nakajo, Niigata-ken, Japan, a clay mineral belonging to the smectite group, was used.

Table 1 Particle Size Distribution Particle Size CM-) Content {%> by weight) above 3 0-1 1-2 2 - 3 49.3 37.3 13-0 0.4 22 77 n (O, Chemical Composition Component Content (% by weight) ignition loss 3-93 Si02 94.10 AJ£2O3 1.05 Fe203 0.15 CaO . 0.49 MgO 0.10 Commercially available sodium aluminate (Na20 = 10 21.0%, Ai2C>3 = 18.8%) and commercially available caustic soda were used as the starting and Na20 materials.

The respective starting materials were mixed and formed into a homogeneous aqueous slurry in which the Na20/S102 molar ratio was 1.2, the Si02/AJl203 molar 15 ratio was 2.0 and the H20/Na20 molar ratio was 35- The slurry was heated at 95"C and reacted with stirring for 3 hours. By this reaction, crystal grains of an alkali metal aluminosilicate (zeolite of the 4A type) were formed. Then, the slurry was aged at 95*C for 2 hours, 20 and the slurry was filtered and deionized water was added to the obtained filter cake to form a homogeneous slurry. The slurry was filtered again and a cake of the v_, zeolite 4A was recovered. The calcium exchange capacity of the obtained zeolite 4A as the product dried at 110*C 25 was 6.2 meq/g as calculated as CaO.

The obtained zeolite 4A cake was dried at 110, 350 or 600"C for 1 hour. Samples NA-11, NA-12, and NA-13 w' were thus obtained. Separately, the obtained zeolite 4A cake was thrown in a solution of calcium chloride to 30 form a homogeneous slurry, and the slurry was stirred for 2 hours to effect ion exchange with the calcium ion. Then, the slurry was filtered, washed and dried. Thus, ion-exchanged zeolite A samples CA-11, CA-12 and CA-13 were obtained. The properties of the obtained samples 35 are shown in Table 2. o o Table 2 J' Sample Na~0 con- CaO con- Ignition Heat treat-tent {% by tent {% by loss {% by ment tempe-weight) weight) weight) rature ( C) NA-11 17.1 - 19.9 110 NA-12 19.2 - 5.8 350 NA-13 19.9 - 2.3 600 CA-11 12.8 4.4 20.3 HO CA-12 8.3 8.1 20.8 110 CA-13 6.3 9.2 20.4 110 (?) O Average Hydrogen chlo-particle ride capture size Cum) quantity (ml/g) 2.15 9.72 2.15 6.82 2.18 6.03 2.16 4.11 2.17 3-74 2.17 3-53 00 1 ro ro ^1 *^i r r- Preparation of Polyvinyl Chloride Pipe A water service pipe of a rigid polyvinyl chloride resin was prepared by using the so-prepared zeolite A in the following manner.

To 100 parts by weight of a vinyl chloride resin having an average polymerization degree P of 1050 were added a lead type stabilizer comprising 0.2 part by weight of tribasic lead sulfate and 1.8 parts by weight of lead stearate, 3-0 parts by weight of heavy calcium 10 carbonate, 0.2 part by weight of a polyethylene type lubricant, 0.3 part by weight of a gray pigment and the above-mentioned zeolite A in an amount shown in Table 3, and the obtained polyvinyl chloride compound was extrusion-molded to obtain a service water rigid 15 polyvinyl chloride pipe (hereinafter referred to as "polyvinyl chloride pipe") having an inner diameter of 13 nun.

With respect to each of the so-obtained polyvinyl chloride pipes, the elusion quantity of lead, the inner 20 surface smoothness, heat stability and other properties were determined according o the above-mentioned methods. The obtained results are shown in Table 3- C) Composition (parts by weight) Zeolite of type A NA-11 NA-12 NA-13 CA-11 CA-12 CA-13 tribasic lead sulfate < lead stearate calcium carbonate polyethylene type lubricant gray pigment Characteristics of pipe inner surface smoothness heat stability (min) lead elusion quantity (ppb) 3 0 Run No. 3 4 6 7 8 1.0 0.5 0.5 0.5 0.5 0.5 0.15 0.2 0.2 0.2 0.2 0.2 1.65 1.8 1.8 1.65 1.8 1.8 3.0 3-0 3-0 3.0 3.0 3-0 0.2 0.2 0.2 0.2 0.2 0.2 0.3 0.3 0.3 0.3 0.3 0.3 ro 0 1 A A B A A A 75 70 65 70 65 65 24 36 41 44 rv> r>o 22 7 7 0 4 From the foregoing results, it is seen that a zeolite of the type A having a hydrogen chloride capture quantity of at least 3 mi/g is added to a polyvinyl chloride pipe, the elusion quantity of lead from the polyvinyl chloride is controlled.

Example 2 In this example, a synthetic zeolite of the type A was prepared by using sodium silicate as the starting silicate material in the following manner, and polyvinyl chloride pipes were prepared by using this zeolite A and lead type stabilizers, calcium carbonate and lubricants shown below. The properties of the obtained polyvinyl chloride pipes were determined.

Preparation of Zeolite of Type A Commercially available water glass (sodium silicate No. 3, Na20 content = 9-5% by weight, Si02 = 27.0% by weight) as the starting silicate material was mixed with commercially available sodium aluminate (Aj^O^ = 22.5% by weight, Na20 = 5>5% by weight) and commercially available caustic soda (NaOH) so that the Na20/Si02 molar ratio was 2, the Si02/Amolar ratio was 2 and the H20/Na20 molar ratio was 60. In a stainless steel vessel having a capacity of 5 JL, water was added to the mixture and a starting dispersion having an entire quantity of about 1 kg was gradually prepared over a long time at room temperature (about 25*C), whereby an entirely homogeneous alkali metal aluminosilicate gel was obtained. The formed gel dispersion was subjected to crystallization reaction at 9^*C for 24 hours, and then, aging was conducted at 95*C for 2 hours. The slurry was filtered, washed with water and washed with a 0.1N aqueous solution of hydrochloric acid, and the obtained zeolite cake was dried at 110*C, 350*C or 600*C for 1 hour. Zeolite 4A, powder samples NA-21, NA-22 and NA-23 were thus obtained. 22 7 Separately, the obtained zeolite 4A cake was subjected to the ion exchange treatment, filtration and water washing in the same manner as described in Example 1. Then, the filter cake was dried at 110"C. Ion-exchanged zeolite A powder samples CA-21, CA-22 and CA-23 were thus obtained.

The properties of the so-obtained zeolite A samples are shown in Table 4. o Table 1 Sample Na~0 con- CaO con- Ignition Heat treat- tent {% by tent {% by loss {% ment tempe- weight) weight) by weight) rature ( C) NA-21 17.1 - 19.9 HO NA-22 18.2 - 6.2 350 NA-23 16.9 - 2.7 600 CA-21 6.7 9-5 20.4 110 CA-22 5.4 11.8 19.2 110 CA-23 2.1 14.4 20.8 110 o o Average Hydrogen chlo-particle ride capture size Qu) quantity (ml/g) 2.15 9.72 2.16 13.33 7-57 3.16 2.17 3-53 7.38 2.28 2.23 1.21 r\j LO no ro o 45% 22 7 7 0 4 Preparation of Polyvinyl Chloride Pipe In the same manner as described in Example 1, 100 parts by weight of a vinyl chloride resin having an average polymerization degree P of 1050 were mixed with amounts, shown in Table 5, of the so-prepared zeolite A, a stabilizer, calcium carbonate, a lubricant and a gray pigment, and the resulting compound was extrusion-molded to obtain a water service rigid polyvinyl chloride pipe having an inner diameter of 13 mm.

With respect to each of the so-obtained polyvinyl chloride pipes, he properties were determined according to the above-mentioned methods. The obtained results are shown in Table 5• In order to clearly demonstrate the effects of the present invention, comparative samples (Runs 22 through 33 shown in Table 5) were similarly tested. The obtained results are shown in Table 5• Composition (parts by weight) Zeolite of type A NA-21 NA-22 NA-23 CA-21 CA-22 CA-23 tribasic lead sulfate dibasic lead stearate lead stearate calcium carbonate polyethylene type lubricant fatty acid ester type lubricant gray pigment Characteristics of Pipe inner surface smoothness heat stability (min) lead elusion quantity (ppb) Table 5 Run No. (present invention) 9 10 11 12 13 14 15 16 17 18 19 20 21 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0 0.2 0.2 0.2 0.2 0.5 0.2 0.2 0.2 0.4 1.8 1.8 1.8 1.8 1.8 1.2 1.8 1.8 H • CO 1.8 1.8 1.8 1.8 3.0 3.0 3.0 3.0 3-0 3-0 1.0 .0 1.0 3.0 .0 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.3 0.6 r\ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 u i A B A B A B B B B B B B B 60 65 65 65 70 80 70 70 70 60 60 60 60 55 44 22 19 28 19 24 6 16 19 ro ro o JSs- Composition (parts by weight) Zeolite of type A NA-21 NA-22 NA-23 CA-21 CA-22 CA-23 tribasic lead sulfate dibasic lead stearate lead stearate calcium carbonate polyethylene type lubricant fatty acid ester type lubricant gray pigment Characteristics of Pipe inner surface smoothness heat stability (min) lead elusion quantity (ppb) O Table 5 (continued) Run No. (comparison) 23 24 25 26 27 28 29 30 31 32 33 0.5 0.5 0.5 0.2 0.8 1.0 0.2 0.2 0.2 0.2 1.8 0.8 0.5 00 * 1—1 1.8 1.8 OO 1.8 1.8 1.8 1.8 3.0 3-0 3.0 1.0 3-0 .0 1.0 3-0 .0 1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 ro OS 1.0 1.5 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 B B C C C B B B B B B 60 85 90 60 60 60 60 55 55 55 55 96 64 108 110 122 128 156 60 64 78 85 ro ro o 4N 22 7 7 From the foregoing results, it is seen that if the composition specified in the present invention is given to a vinyl chloride resin for a water service pipe and the specific zeolite is incorporated according to the present invention, elusion of lead from a water service rigid polyvinyl chloride pipe can be prominently controlled.

Example 3 A water service polyvinyl chloride pipe was prepared in the same manner as described in Example 1 except that a lead stabilizer comprising a combination of a lead salt of a fatty acid and a tin type stabilizer or metal soap type stabilizer, shown in Table 6, was used as the stabilizer. The effect of controlling the elusion of lead was examined in the same manner as described in Example 1. The obtained results are shown in Table 6.

Composition (parts by weight) Table 6 (present invention) 34 35 36 (comparison) 37 38 Zeolite 0.5 0.5 0.5 butyl tin maleate polymer 0.25 0.2 0.2 calcium type metal soap 0.3 0.2 0.2 lead stearate 1.8 1.8 OO • 1—1 1.8 1.8 calcium carbonate 3.0 3.0 3.0 3.0 3.0 polyethylene type lubricant 0.2 0.2 0.2 0.2 0.2 gray pigment 0.3 0.3 0.3 0.3 0.3 Characteristics of Pipe inner surface smoothness B B B B B heat stability (min) 85 70 65 60 55 lead elusion quantity (ppb) 19 14 77 78

Claims (15)

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1. A water service pipe which is composed of a resin composition comprising 100 parts by weight of a 5 chlorine-containing polymer, 0.1 to 5.0 parts by weight of a lead type stabilizer comprising a lead salt of a fatty acid, a combination of a lead salt of a fatty acid and a basic lead salt, a combination of a lead salt of a fatty acid and a tin type stabilizer or a combination of 10 a lead salt of a fatty acid and a metal soap type stabilizer, 0.01 to 15 parts by weight of a calcium carbonate filler, up to 5.0 parts by weight of a lubricant and 0.01 to 3-0 parts by weight of a zeolite of the type A. 15

2. A water service pipe as set forth in claim 1, wherein the zeolite of the type A is a zeolite of the sodium type and/or calcium type and the hydrogen chloride capture quantity (C) of the zeolite, defined as the quantity of hydrochloric acid necessary for reducing 20 the pH value of the zeolite to 5 from 9 by using a 0.4N aqueous solution of hydrochloric acid, is at least 3 m£/

3. A water service pipe as set forth in claim 1, wherein the zeolite of the type A is a zeolite having such characteristics that the maximum reduction gradient 25 (Rmax) determined from the tangential line of the maximum gradient portion of the hydrochloric acid titration curve is -0.1 to -0.7 pH/meq HC2 per 100 g of the zeolite, and the maintenance pH reduction gradient (Rmain) determined from the tangential line of the 30 subsequent small-inclination portion of the hydrochloric acid titration curve is -0.001 to -0.07 pH/rneq HC-£ per 100 g of the zeolite.

4. A water service pipe as set forth in claim 1, wherein the chlorvine-containing polymer is a vinyl 35 chloride resin. -irss. ir

♦A*.--.-;• £>;o;5;©;10 15 20;c;25 30;isqy;7 7;- 30 -;5. A water service pipe as set forth in claim 1, wherein the lead salt of the fatty acid is lead stearate.;

6. A water service pipe as set forth in claim 1, wherein the basic lead salt is tribasic lead sulfate.;

7. A water service pipe as set forth in claim 1, wherein the tin type stabilizer is a butyl-tin maleate polymer.;

8. A water service pipe as set forth in claim 1, wherein the metal soap stabilizer is a calcium stearate.;

9. A water service pipe as set forth in claim 1, wherein the lubricant is a member selected from the group consisting of waxes, higher fatty acids and derivatives thereof.;

10. A one-package additive for a chlorine-containing polymer, which comprises (i) a lead type stabilizer comprising a lead salt of a fatty acid, a combination of a lead salt of a fatty acid and a basic lead salt, a combination of a lead salt of a fatty acid and a tin type stabilizer or a combination of a lead salt of a fatty acid and a metal soap type stabilizer, (ii) a calcium carbonate filler, (iii) a lubricant and (iv) a zeolite of the type A, the respective components being mixed in the weight ratio of (i)/(ii)/(iii)/(iv) = 0.1-5/0.01-15/0-5/0.01-3.;

11. A one-package additive as set forth in claim io, wherein the zeolite of the type A ia a zeolite having such characteristics that the maximum reduction gradient (Rmax) determined from the tangential line of the maximum gradient portion of the hydrochloric acid titration curve is -0.1 to -0.7 pH/meq HCJ2, per 100 g of the zeolite, and the maintenance p^reductiSJT'grad^i;rjmj*' 5 G 10 15 20 0 25 o 30 227704 (Rmain) determined from the tangential line of the subsequent small-inclination portion of the hydrochloric acid titration curve is -0.001 to -0.07 pH/meq HCX per 100 g of the zeolite.

12. A stabilizer for a chlorine-containing polymer, which comprises sodium aluminosilicate or calcium aluminosilicate having an X-ray diffraction pattern inherent to a zeolite of the type A or a mixture thereof, wherein the hydrogen chloride capture quantity (C) defined as the quantity of hydrochloric acid necessary for reducing the pH value of the zeolite to 5 from 9 by using a 0.4N aqueous solution of hydrochloric acid is at least 3 nU/g, the maximum reduction gradient (Rmax) determined from the tangential line of the maximum gradient portion of the hydrochloric acid titration curve is -0.1 to -0.7 pH/meq HC,£ per 100 g of the zeolite, and the maintenance pH reduction gradient (Rmain) determined from the tangential line of the subsequent small-inclination portion of the hydrochloric acid titration curve is -0.001 to -0.07 pH/meq HC/. per 100 g of the zeolite.

13. A water service pipe as claimed in claim 1 and substantially as herein described with reference to the drawings and/or the examples.

14. A one-package additive as claimed in claim 10 and substantially as herein described with reference to the drawings and/or the examples.

15. A stabilizer as claimed in claim 12 and substantially as herein described with reference to the drawings and/or the examples. OATLL) Tms DAY OF A. J. PAR PER^f -Qto AGENTS FOR THEl/APPLlCANT: