Heavy metal-free halogenated components

Abstract

The disclosed technology relates to chlorine-containing polymers, such as polyvinyl chloride and its copolymers, that are free of heavy metals, particularly heavy metals in the form of stabilizer additives, the most common of which is tin. In one embodiment, the disclosed technology provides a stabilized halogenated resin composition, such as a polyvinyl chloride (PVC) or chlorinated polyvinyl chloride (CPVC) composition. The stabilized composition may comprise (a) a halogenated resin such as a PVC resin or a CPVC resin and (b) a barbiturate derivative stabilizer.

Description

Technical Field

[0001] The disclosed technology relates to chlorine-containing polymers such as polyvinyl chloride and its copolymers, and the compounds do not contain heavy metals, especially heavy metals in the form of stabilizer additives, and the most common heavy metal is tin.

Background Art

[0002] Halogen-containing polymers tend to decompose or deteriorate when processed. Generally, the difference between the processing temperature and the decomposition temperature is very small, so there is a risk that the halogen-containing polymer will decompose. When such a polymer decomposes, the halide acid produced by the polymer is considered to attack the components of the processing apparatus. Also, this acid further catalyzes the elimination reaction and further decomposition of the polymer.

[0003] Stabilizers have been developed to help prevent such decomposition. For example, heavy metal compounds such as tin are commonly used as heat stabilizers. However, heavy metal stabilizers are becoming less preferred as heat stabilizers for halogenated polymers due to environmental concerns.

[0004] It would be beneficial to the industry to prepare inexpensive and readily available alternatives to current stabilizer systems for halogenated resins such as polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC) resins, and the like.

Summary of the Invention

Means for Solving the Problems

[0005] Therefore, the disclosed technology solves the problem of providing a heavy metal-free halogenated resin composition by including a barbiturate derivative stabilizer in the composition.

[0006] In one embodiment, the disclosed technology provides a stabilized halogenated resin composition, such as a polyvinyl chloride (PVC) or chlorinated polyvinyl chloride (CPVC) composition. The stabilized composition may comprise (a) a halogenated resin such as a PVC resin or a CPVC resin and (b) a barbiturate derivative stabilizer.

[0007] In the embodiment, the barbiturate derivative stabilizer may be present in the stabilized halogenated resin composition in an amount of about 0.1 to about 6.0 parts by weight per 100 parts by weight of the halogenated resin.

[0008] In the embodiment, the composition is substantially free or even free of heavy metal-containing stabilizers.

[0009] In another aspect of the present invention, a pipe or pipe fitting made from a halogenated resin composition according to any of the above embodiments is provided.

[0010] The present invention also provides a method for stabilizing a halogenated resin composition. This method involves using a barbiturate derivative stabilizer in the halogenated resin composition.

[0011] In this embodiment, the compositions and methods of this technology generally exclude heavy metals, and in particular heavy metal stabilizers such as tin stabilizers. [Modes for carrying out the invention]

[0012] Various preferred features and embodiments are described below by non-limiting examples.

[0013] One aspect of the present invention is a rigid halogenated resin composition comprising (a) a halogenated resin and (b) a stabilizer containing a barbiturate derivative. The term "salt derivative" relates to the fact that barbituric acid forms complexes with alkalis or alkaline earth metals.

[0014] Barbiturate derivatives may include, for example, 1,3-disubstituted barbiturates and 1,3,5-trisubstituted barbiturates. The substituents are hydrocarbyl substituents.

[0015] As used herein, the terms “hydrocarbyl substituent” or “hydrocarbyl group” are used in their ordinary sense as is well known to those skilled in the art. Specifically, they refer to groups having carbon atoms directly bonded to the rest of the molecule and having primarily hydrocarbon properties. Examples of hydrocarbyl groups include:

[0016] Hydrocarbon substituents, i.e., aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, as well as aromatic, aliphatic, and alicyclic substituted aromatic substituents, and cyclic substituents in which the ring is completed via another part of the molecule (e.g., two substituents together form a ring);

[0017] Substitutive hydrocarbon substituents, i.e., substituents in the context of the present invention that contain non-hydrocarbon groups that do not primarily alter the hydrocarbon properties of the substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);

[0018] Heterosubstituted substituents, in the context of the present invention, are substituents that primarily possess hydrocarbon properties, but otherwise contain non-carbon atoms in a ring or chain composed of carbon atoms, and include substituents as pyridyl, furyl, thienyl, and imidazolyl. Examples of heteroatoms include sulfur, oxygen, and nitrogen. Generally, there will be two or fewer, or one or fewer, non-hydrocarbon substituents for every 10 carbon atoms in the hydrocarbyl group, and alternatively, there may be no non-hydrocarbon substituents in the hydrocarbyl group.

[0019] In one embodiment, the substituent may be, for example, an aliphatic or aromatic substituent, and may be an alkyl, cycloalkyl, allyl, or aryl substituent. In another embodiment, the substituent may include a heteroatom.

[0020] Barbiturates having one substituent each at the 1- and 3-positions and one substituent each at the 1-, 3-, and 5-positions can be used. In embodiments, the barbiturate derivatives can be 1,3-disubstituted barbiturates or 1,3,5-trisubstituted barbiturates, such as N,N’1,3-dialkylbarbiturates or 1,3,5-trialkylbarbiturates. Metal salts are also possible.

[0021] In embodiments, the barbiturate derivative stabilizer has the following formula I:

[0022]

Chemical formula

[0023] In embodiments, the hydrocarbyl groups, R1 to R3, can independently be alkyl groups. The alkyl group R of the barbiturate derivative stabilizer can be straight-chain or branched-chain and may contain unsaturation. In many cases, the R group can be an alkyl group having 1 to 18 carbon atoms.

[0024] Also, R1 to R3 can independently be aromatic groups, such as a benzyl group or a phenyl group.

[0025] In any case, the hydrocarbyl R group may contain heteroatoms such as, for example, halogen, sulfur, oxygen, or nitrogen.

[0026] The M-group metal, if present, is not particularly limited to alkali and alkaline earth metals, but sodium, potassium, magnesium, and calcium are most frequently used, with sodium being the most common.

[0027] In the embodiment, the barbiturate derivative stabilizer may include an N,N'-1,3-dimethylbarbiturate salt stabilizer containing sodium N,N'-1,3-dimethylbarbiturate. Other barbiturate derivative stabilizers include, for example, N,N'-1,3-dihexyl barbiturate, N,N'-1,3-didodecyl barbiturate, 1,3-dioctodecyl barbiturate, and N,N'-1,3-diphenyl barbiturate, each including its branched and unsaturated derivatives such as, for example, N,N'-1,3-di-sec-butyl barbiturate, N,N'-1,3-di-isooctyl barbiturate, N,N'-1,3-di-tert-cedecyl barbiturate, and N,N'-1,3-penta-1-ene barbiturate, N,N'-1,3-undeca-3-ene barbiturate, and N,N'-1,3-(2-methylpropa-1-ene)-barbiturate.

[0028] The halogenated polymer resin is present in the composition at 100 parts by weight, and the concentrations of all other components are based on levels per 100 parts by weight of the halogenated polymer resin. In this specification, the abbreviation "phr" is used to express the amount of additive components by weight based on 100 parts by weight of the halogenated resin. Barbiturate derivative stabilizers may be present in the stabilized halogenated resin composition in amounts of about 0.1 to about 6 phr, or about 0.1 to about 5 phr, or about 0.1 to about 4 phr. In some embodiments, barbiturate derivative stabilizers may be present in the stabilized halogenated resin composition in amounts of about 0.25 to about 3.75, or about 0.5 to about 3.5 phr, or about 0.75 to about 3.25 phr, or about 1 to about 3 phr.

[0029] The halogenated polymer resin used in the composition is not particularly limited. Halogenated polymer resins may include polymers used in many different applications, such as residential and commercial plumbing for drinking water or wastewater, waste, and vent applications; residential and commercial fire sprinkler systems; residential and commercial profile applications, such as paneling, window frames, cabinet finishes, flooring, aircraft interiors, roof tiles, capstock, etc.; industrial pipes for chemical processing or wastewater treatment; semiconductor applications; wire and cable applications; conduit; masterbatch applications, etc., as well as those used in associated fixtures and molded components for each application. Examples of halogenated polymers include polyvinyl chloride ("PVC") or polyvinyl chloride ("CPVC") homopolymers, including polyvinyl chloride polymers; copolymers of polyvinyl chloride with ethylene-type unsaturated compounds, such as PVC-VA (vinyl acetate) copolymer, PVC-acrylate, chlorinated polyethylene ("CPE"), and polychloroprene.

[0030] Halogenated resins may include polyvinyl chloride ("PVC"), for example, homopolymers of polyvinyl chloride resins, copolymers of polyvinyl chloride resins, and mixtures thereof. Copolymers of polyvinyl chloride are formed by copolymerization of polyvinyl chloride with other monomers or monomer blends. Suitable monomers include vinyl acetate, ethylene, propylene, maleate, methacrylate, acrylate, higher alcohol vinyl esters, urethane, chlorinated urethane, methyl methacrylate, and mixtures thereof.

[0031] A specific halogenated polymer for the composition may be a CPVC resin, also simply called CPVC. For a typical pipe or fitting resin, the CPVC according to the present invention may contain less than about 11.0 mol%, or about 1.0 to about 10.0 mol%, or about 3.0 to about 9.0 mol% of CCl2. Generally, a smaller amount of CCl2 is preferable for the CPVC resin. In another embodiment, the CPVC according to the present invention may also contain about 52.0 to about 66 mol%, or about 54.0 to about 60.0 mol%, of CHCl.

[0032] The present invention further intends that the CPVC resin may contain several unsaturated bonds (i.e., double bonds) along its skeleton. CPVC according to one aspect of the present invention may contain about 0.0 to about 4.0 mol% or about 1.0 to about 3.0 mol%. For example, for every 100 carbon bonds in the CPVC skeleton, an average of about 0.0 or 1.0 to an average of about 4.0 unsaturated bonds may be present.

[0033] In contrast to CPVC, PVC contains only about 50% CH2 and 50% CHCl, with no CCl2 content, and its unsaturation is very close to 0%.

[0034] CPVC can be prepared by chlorinating poly(vinyl chloride) (PVC) polymer. There are considerations regarding the precursor PVC from which the post-polymerization chlorinated product (CPVC) used in this invention originates. The molecular weight of PVC, as expressed by intrinsic viscosity (IV) measurements according to ASTM D1243, should generally be in the range of about 0.4 to about 1.4 dL / g in extreme cases. Preferably, the IV of the precursor PVC used falls within the range of about 0.6 to about 1.4 dL / g for pipes and fittings, generally about 0.90 to about 1.05 dL / g for pipes and generally about 0.6 to about 0.8 dL / g for fittings. The preferred polymerization method for preparing the PVC is the aqueous suspension method, which is the primary method used in the art. A detailed description of the suspension process is beyond the scope of this invention and is therefore not disclosed. The suspension process for the polymerization of PVC is described in The Encyclopedia of PVC, Marcel Decker, Inc. (1976).

[0035] CPVC suitable for use in the present invention may be derived from a PVC copolymer having about 5 parts or less of comonomers. If the precursor PVC contains one or more comonomers in total of less than about 5 parts per 100 parts of vinyl chloride, the chlorinated version of this polymer is also referred to herein as CPVC.

[0036] Comonomers for both PVC and CPVC include esters of acrylic acid having 1 to 12 carbon atoms in the ester moiety, such as methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, cyanoethyl acrylate, etc.; vinyl acetate; esters of methacrylic acid having 1 to 12 carbon atoms in the ester moiety, such as methyl methacrylate (MMA), ethyl methacrylate, butyl methacrylate, etc.; acrylonitrile and methacrylonitrile; styrene derivatives having a total of 8 to 15 carbon atoms, such as alpha-methylstyrene, vinyltoluene, chlorostyrene; vinylnaphthalene; and diolefins having a total of 4 to 8 carbon atoms, such as isoprene, including halogenated olefins such as chlorobutadiene, monoolefins such as ethylene and propylene, and having 2 to 10 carbon atoms, preferably 2 to 4 carbon atoms, preferably 4 carbon atoms, with isobutylene being very preferred. When using comonomers, copolymerizable imides such as MMA and N-cyclohexylmaleimide, and comonomers known to copolymerize with vinyl chloride monomers to produce copolymers having a Tg greater than or equal to homoPVC are preferred. Preferred CPVCs are derived from PVC homopolymers. Among these, it is intended that a small portion of the solvent in which PVC polymerizes can copolymerize with it. For example, vinyl chloride can be advantageously prepared in the presence of chain-modifying coreactant solvents such as ethylenically unsaturated alkylenes such as THF and alpha-olefins, or reactive mercaptans such as 2-mercaptoethanol, and a small portion of it may be present as a comonomer in the resulting PVC.

[0037] The CPVC resin may contain CPVC having a specified weight percentage (wt%) of chlorine, about 57.0 to about 70.0 wt%, more preferably about 60.0 to about 69.0 wt%, even more preferably about 63.0 to about 68.0 wt%, and most preferably about 64.0 or 65.0 to 67.5 wt%. The weight percentage of chlorine is based on the weight of the CPVC resin.

[0038] The halogenated polymer may be chlorinated polyethylene (CPE). CPE is a rubbery substance obtained from the chlorination of polyethylene having a substantially linear structure. Polyethylene can be chlorinated by various methods, including aqueous suspension, solution, or gas phase methods. An example of a method for preparing CPE can be found in U.S. Patent No. 3,563,974. Preferably, CPE is formed using the aqueous suspension method. When used as an impact modifier, the CPE material contains 5 to 50% by weight of chlorine. Preferably, the CPE contains 25 to 45% by weight of chlorine. However, the CPE may contain a mixture of chlorinated polyethylenes, provided that the mixture as a whole has a chlorine content in the range of about 25 to 45% by weight of chlorine.

[0039] In embodiments, the halogenated resin may be rigid. Rigid CPVC as used herein can be defined according to ASTM D883. More specifically, the rigid polymer as used herein means a polymer having either a flexural modulus or tensile modulus of 700 MPa (100,000 psi) or greater, measured at a temperature of 23°C in an atmosphere of 50% relative humidity, when tested according to test methods ASTM D747, D790, D638, or D882.

[0040] The halogenated polymer composition may contain, in addition to the halogenated polymer and barbiturate derivatives, other components typically added to halogenated polymer compositions. The amounts and properties of these components depend on the end use of the composition. The components and their amounts can be adjusted by those skilled in the art to meet the needs of the end use. Examples of additives that can be used include other stabilizers, antioxidants, lubricants, other impact modifiers, pigments, glass transition strengthening additives, processing aids, fusion aids, fillers, fiber strengtheners, and antistatic agents.

[0041] For example, in addition to barbiturate derivative stabilizers, the composition may include other stabilizers known for halogenated polymer compositions. For instance, the composition may include organic stabilizers, zeolites, and carboxylates, which are known stabilizers.

[0042] In simple terms, organic stabilizers (OB stabilizers) are nonmetal-containing stabilizers based on organic chemistry. While the OB stabilizers suitable for the stabilizer systems described herein are not particularly limited, the most common OB stabilizer compounds today include uracil and its derivatives. A common derivative of uracil suitable as an OB stabilizer for the compositions described herein is 6-amino-1,3-dimethyluracil. Other commercially available OB stabilizers suitable for the compositions of the present invention include, for example, the Mark®OBS® series stabilizers available from Galata®.

[0043] Generally, OB stabilizers may be included in the composition at levels necessary to satisfy physical properties such as color. The OB stabilizer may be present in an amount of about 0.05 or 0.1 to about 2.0 parts by weight per 100 parts by weight of the CPVC resin. In some embodiments, the OB stabilizer may be present in an amount of about 0.15 to about 1.75 phr, or about 0.2 to about 1.5 phr, or even about 0.25 or 0.5 to about 1.25 phr.

[0044] Zeolites essentially contain a three-dimensional framework of SiO4 and AlO4 tetrahedra. The tetrahedra are bridged by sharing oxygen atoms such that the ratio of oxygen atoms to the sum of aluminum and silicon atoms is equal to 2. This relationship is expressed as O / (Al+Si)=2. The electric valence of the aluminum and silicon-containing tetrahedra is maintained in equilibrium in the crystal by the presence of cations. For example, the cations may be alkali metal ions or alkaline earth metal ions. The cations may be replaced with others depending on the end use of the aluminosilicate zeolite. The spaces between the tetrahedra of the aluminosilicate zeolite are usually occupied by water. Zeolites may be natural or synthetic.

[0045] The basic formula for all aluminosilicate zeolites is expressed as follows: M 2 / n O:[Al2O3] x :[SiO2] y :[H2O] z (In the formula, M represents a metal, n represents the valence of the metal, and X, Y, and Z vary depending on the specific aluminosilicate zeolite.) Essentially, in the present invention, any aluminosilicate zeolite can be used as a stabilizer, provided that the ratio of silicon to aluminum in such aluminosilicate zeolite is less than 3.0 and that the aluminosilicate zeolite can be incorporated into the halogenated composition. Preferably, the zeolite ratio of silicon to aluminum in such aluminosilicate zeolite is less than 1.5. Most preferably, the ratio of silicon to aluminum in such aluminosilicate zeolite is about 1.

[0046] Preferred zeolites may include sodium-incorporated aluminum hydrate silicates of the type mNa2O·xAl2O3.ySiO2·zH2O, either alone or in combination with another Group I metal. These preferred zeolites include zeolites A, P, X, and Y.

[0047] In the prior art, it is preferable to include zeolites with submicron particle sizes (for example, volume-based D50 of less than 1 micron). However, at least one zeolite with any particle size distribution, particle size, and water content may be used as a single stabilizer, or C6~C 12 It has been found that it can be used in combination with metal carboxylates and OB stabilizers.

[0048] In some embodiments, the zeolite may be present at about 0.25 to about 3.5 phr or 0.5 to about 3.0 phr. In preferred embodiments, the zeolite may be present at about 0.75 to about 1.5 or 2.5 phr.

[0049] A halogenated polymer (e.g., CPVC) composition may contain an acrylic impact modifier. U.S. Patent No. 3,678,133 describes a composition conventionally called an acrylic impact modifier. Generally, an acrylic impact modifier is a composite interpolymer comprising a multiphase acrylic substrate including a first elastomer phase polymerized from a monomer mixture containing at least 50% by weight of alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group and a molecular weight of 50,000 to 600,000 Daltons. Furthermore, this patent states that it is preferable that the polymerization of the hard thermoplastic phase be carried out such that substantially all of the hard phase material is formed on or near the surface of the elastomer phase. Acrylic impact modifiers include (C4~C 12 ) Polyacrylates comprising acrylate homopolymers or copolymers obtained by second-step graft copolymerization with methyl methacrylate and styrene, poly(ethylhexyl acrylate-co-butyl acrylate) obtained by graft copolymerization with styrene, and / or acrylonitrile and / or methyl methacrylate; polybutyl acrylate obtained by graft polymerization with acrylonitrile and styrene. Examples of suitable acrylic impact modifiers include Paraloid® EXL-2330, KM® 330, 334, and 365, all of which are available from Rohm and Haas. Paraloid is a trademark of the Rohm & Haas Company. Furthermore, Durastrength® 200, available from Elf Atochem, and Kane Ace® FM-10 and FM-25, available from Kaneka, are examples of commercially available acrylic impact modifiers.

[0050] Methyl butadiene styrene ("MBS") impact modifiers may be added to the compounds of the present invention. MBS polymers are graft polymers. Generally, MBS impact modifiers are prepared by polymerizing methyl methacrylate or a mixture of methyl methacrylate and other monomers in the presence of polybutadiene or polybutadiene-styrene rubber. Further information on MBS impact modifiers can be found in the Encyclopedia of PVC, 2nd edition, edited by Leonard I. Nass, Marcel Dekker, Inc. (NY 1988, pp. 448-452). Examples of commercially available MBS impact modifiers include Paraloid KM® 680, BTA® 733, 751, and 753 available from Rohm & Haas, and Kane Ace® B-22 and Kane Ace® B-56 ​​impact modifiers available from Kaneka.

[0051] A typical example of a graft copolymer impact modifier is what is commonly called "ABS" resin, which is generally described as a copolymer of styrene and acrylonitrile in butadiene-containing rubber. ABS modifiers are usually prepared by polymerizing styrene and acrylonitrile in the presence of polybutadiene rubber. Examples of commercially available ABS impact modifiers that can be used in this invention include Blendex 338, Blendex 310, and Blendex 311, all of which are available from GE Plastics. When used as a selected impact modifier, about 5 to 15 parts of the ABS impact modifier are used. Preferably, 6 parts of the ABS impact modifier are used.

[0052] As described above, chlorinated polyethylene (CPE) can also be used in the composition in sufficient quantities to act as an impact modifier.

[0053] Exemplary lubricants include di- and trioleate polyglycerols, Fischer-Tropsch waxes, polyolefins such as polyethylene and polypropylene, and oxidized polyolefins such as oxidized polyethylene, and high molecular weight paraffin waxes. Since several lubricants can be combined in countless variations, the total amount of lubricant can vary depending on the application. Optimization of a particular lubricant composition is not within the scope of the present invention and can be easily determined by those skilled in the art. Preferably, oxidized polyethylene is used. An example of oxidized polyethylene is AC 629A, sold by Allied Signal. In addition to oxidized polyethylene, paraffin wax may also preferably be included in the compounds of the present invention. An example of paraffin wax is Paraffin 160F Prill, manufactured by Witco.

[0054] Suitable processing aids include acrylic polymers, such as methyl acrylate copolymers. Examples of processing aids include Paraloid K-120ND, K-120N, and K-175, all available from Rohm & Haas. Descriptions of other types of processing aids that can be used in the compound can be found in The Plastics and Rubber Institute: International Conference on PVC Processing, April 26-28 (1983), Paper No. 17.

[0055] An example of an antioxidant used in halogen-containing compounds, when used in its entirety, is Irganox 1010 (tetrakis[methylene(3,5-di-tert-butyl-4-hydroxy-hydrocinnamate)]methane), sold by BASF.

[0056] Suitable pigments include, in particular, titanium dioxide and carbon black. Examples of titanium dioxide include Tiona RCL-6 and RCL-4 from Millennium Inorganics. An example of carbon black is Raven 410, available from Columbia Chemicals.

[0057] Suitable inorganic fillers include talc, clay, mica, wollastonite, silica, and other fillers.

[0058] The components of the unique compound can be prepared by any method of adding various components together and mixing them under heat. For example, an appropriate amount of halogenated polymer (e.g., CPVC) resin may be added to a container such as a Henschel mixer or ribbon blender. The remaining components of the compound may then be added and mixed until the blend is homogeneous. When forming pellets, the compound may be melt-mixed. Melt-mixing may generally be carried out in a temperature range of about 150 to about 250°C. Once the blend is formed, it can be further processed by any conventional method using extrusion or molding techniques, depending on the desired application.

[0059] When using extrusion technology to process the compositions of the present invention, conventional extrusion machines such as multi-screw extruders or single-screw extruders are generally used. Extruders generally have conveying means, intermediate screwing means, and a final die from which the material is discharged in the form of an extruded product. Multi-screw extruders are generally used for extruding pipes. Examples of conventional extruders that can be used to process CPVC and PVC compounds containing modified zeolite include the following twin-screw counter-rotating extruder models from Cincinnati Milacron: CM 35HP, CM 55HP, CM 65HP, CM 80HP, and CM 92HP. Examples of suitable conical twin-screw extruders from Krauss Maffei include KMD-2 / 40KK and KMD-2 / 50KK.

[0060] The halogenated polymer (e.g., CPVC) compositions prepared according to the present invention have the following characteristics: tensile strength in the range of about 5,000 to about 10,000 psi (measured according to ASTM D 638-95); notched izod in the range of about 1.0 to about 20 ft. lb per notch (measured according to ASTM D 256-93A); and dynamic thermal stability of more than 14 minutes, for example in the range of about 14 to about 60 minutes, when measured according to ASTM D 2538 unless otherwise specified: 1) Unless otherwise specified, set the reverse batch mixing bowl to 190°C according to the formula and place 75 grams of the sample into the batch mixer; 2) Load the sample at 10 rpm for 1 minute, then gently mix at 1 rpm for 0.5 minutes, and then operate at 35 rpm until the sample decomposes. Stabilization timing starts at 35 rpm; 3) Six minutes after the start of sample loading, when the machine reaches 35 rpm, take a small pinch sample, and then take samples every two minutes thereafter. The thermal distortion temperature is in the range of approximately 80 to 140°C (measured according to ASTM D 648-95). This novel compound can be molded into any desired article. Examples include, but are not limited to, sheets, pipes, ducts, fittings, valves, injection-molded and thermoformed industrial parts, electrical appliance housings, assemblies, and various containers.

[0061] In a preferred embodiment, the halogenated composition may be used to prepare a pipe or pipe fitting.

[0062] Pipes or pipe fittings prepared from halogenated compositions can meet the cell class specifications for their respective chemistry. For example, pipes or pipe fittings made from CPVC formulations can meet cell class 23447 and can also be adjusted to meet cell class grade 24448. The first digit "2" in the cell class designation identifies the type of resin; in the case of "2", the resin is for CPVC pipes or pipe fittings; the second digit (either "3" or "4") identifies the level of notched Izod impact strength; "3" indicates at least 80.1 J / m (1.5 ft. lb / in) of notches, and "4" indicates at least 266.9 J / m (5 ft. lb / in) of notches; the third digit "4" identifies a tensile strength of at least 48.3 MPa (7,000 psi); the fourth digit "4" identifies a tensile modulus of elasticity of at least 2482 MPa (360,000 psi); and the fifth digit (either "7" or "8") identifies the level of DTUL or HDT measured under a load of 1.82 MPa (264 psi). The number "7" indicates DTUL or HDT at least 100C, and "8" indicates DTUL or HDT at least 110C (see ASTM D1784).

[0063] Pipes or pipe fittings made of PVC may meet cell class 12444. The first digit "1" in the cell class designation identifies the resin type as PVC; the second digit identifies the level of notched Izod impact strength, with "2" indicating at least 34.7 J / m (0.65 ft. lb / in) notched; the third and fourth digits are the same as CPVC above; and the fifth digit "4" indicates at least 70C DTUL or HDT (see ASTM D1784).

[0064] In another embodiment, the present invention includes a method for stabilizing a halogenated polymer (e.g., CPVC) composition. This method includes the step of using a barbiturate derivative in the halogenated polymer composition.

[0065] Since some of the materials described above can interact in the final formulation, it is known that the components of the final formulation may differ from those initially added. For example, metal ions (e.g., in detergents) can migrate to other acidic or anionic sites of other molecules. The products formed thereby, including those formed when the composition of the present invention is used in its intended application, may not be readily apparent. Nevertheless, all such modifications and reaction products are within the scope of the present invention. The present invention encompasses compositions prepared by mixing the components described above.

[0066] The present invention is useful for preparing stable halogenated compositions, particularly halogenated compositions that can be extruded into pipes or formed into pipe fittings, which can be better understood by referring to the following examples. [Examples]

[0067] Sample Preparation Procedure - Resin Wet-Coated with Stabilizer - For water-soluble stabilizers, wet-blend the resin and dry it. As a stabilizer solution, dissolve 1.5 phr of stabilizer in 15 phr of total aqueous solution. Add the 15 phr aqueous solution to 100 phr of PVC in a blender and mix until uniformly combined to form a wet cake. Dry the resulting resin wet cake overnight in a flat tray at room temperature in a natural vent hood to reach equilibrium moisture content (natural drying).

[0068] Sodium dimethylbarbiturate is prepared by neutralizing the stabilizer -1,3-dimethylbarbituric acid with an equimolar amount of NaOH. A 15 phr aqueous solution containing 1.5 phr of sodium dimethylbarbiturate is blended with 100 phr of PVC according to the wet blending method described above.

[0069] Other stabilizers are available in powder form. Mix all powder ingredients together using a Ware blender.

[0070] DTS Measurement - Dynamic Thermal Stability (DTS) is measured according to ASTM D 2538. A longer DTS time indicates improved stability of the compound.

[0071] The melt stability is investigated using a Brabender™ DTS batch mixer. One method for determining the stabilization time is a visual inspection of the appearance of the molten material, which indicates the decomposition time. When the molten material is about to fade, its color typically starts as white or light brown (tan white) and progresses to a very noticeable pinkish, brownish, or even darker color. Monitoring the color change by picking small pieces of the molten material to record the color at selected time intervals is also a good method for studying melt stability. Higher DTS stability is preferable.

[0072] The DTS procedures used herein, unless otherwise specified, are as follows: 1) Unless otherwise specified, set the reverse batch mixing bowl to 190°C according to the formula and add 75 grams of the sample to the batch mixer. 2) Load the sample at 10 rpm for 1 minute, then gently mix at 1 rpm for 0.5 minutes, and then run at 35 rpm until the sample decomposes. Stabilization timing begins with the initial sample loading. 3) Take a small pinch sample 6 minutes after the start of the procedure, and then take samples every 2 minutes thereafter.

[0073] Example 1: Brown color retention stability using the DTS sample pinching method Table 1 below shows formulations containing various amounts of acid-scavenging stabilizer and 0.25 phr of OB stabilizer 6-amino-1,3-dimethyluracil, blended together with other additives in a compound with 0.92 IV of PVC resin. The amount of stabilizer is fixed at 1.5 phr per 100 phr of PVC. 101.5 indicates that the PVC is wet-coated with 1.5 phr of stabilizer. Otherwise, 1.5 phr of stabilizer is shown separately in the formulation examples.

[0074] Table 1 also provides color stability times. The above formulations are tested for color retention stability in brown compounds.

[0075] Color retention stability is another measure of melt stability. During DTS melt mixing, small samples of the compound are taken using sampling pliers. Less than 0.5 grams of melt are picked up at a time. The trimmed color fragments are typically 0.25–0.3 grams.

[0076] [Table 1]

[0077] Each of the documents mentioned above, including any prior application claiming priority, whether or not they are specifically listed above, is incorporated herein by reference. Reference to any document does not constitute an endorsement that such document is eligible as prior art or constitutes the general knowledge of a person skilled in the art in any jurisdiction. Except in the examples or unless otherwise expressly indicated, all quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, etc., should be understood to be modified by the word "about." The upper and lower limits of quantities, ranges, and ratios described herein can be combined independently. Similarly, the ranges and quantities for each element of the present invention can be used together with the ranges or quantities for any of the other elements.

[0078] As used herein, the transitional term “comprising,” which is synonymous with “including,” “contains,” or “characterized by,” is inclusive or open-ended and does not exclude additional undescribed elements or method steps. However, in each “comprising” statement herein, the term is also intended to include, as alternative embodiments, the phrases “essentially from” and “consisting of,” where “consisting of” excludes any unspecified elements or steps, and “essentially from” allows the inclusion of additional undescribed elements or steps that do not substantially affect the basic and novel features of the composition or method under consideration.

[0079] For the purpose of illustrating the present invention, certain representative embodiments and details have been shown, but it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the invention. In this regard, the scope of the invention should be limited only by the following claims.

Claims

1. A halogenated polymer (e.g., PVC, CPVC) composition comprising (a) a halogenated polymer (e.g., chlorinated polyvinyl chloride (CPVC, PVC) resin) and (b) a barbiturate derivative.

2. The aforementioned barbiturate derivative is of formula I: 【Chemistry 2】 (In the formula, R １ and R ２ Each of these is independently a hydrocarbyl group with 1 to 18 carbon atoms, R ３ The halogenated polymer composition according to claim 1, comprising a compound of (where is H or a hydrocarbyl group of 1 to 18 carbon atoms, M is an alkali metal or alkaline earth metal, and x is 1 or 2).

3. The composition according to claim 1 or 2, wherein the barbiturate derivative stabilizer is present in an amount of about 0.1 to about 6.0 parts by weight per 100 parts by weight of the PVC resin and the CPVC resin.

4. The composition according to any one of claims 1 to 3, which is substantially free of or free of heavy metal-containing stabilizers.

5. The composition according to any one of claims 1 to 4, further comprising an auxiliary stabilizer selected from the group consisting of organic stabilizers, zeolites, and combinations thereof.

6. The halogenated polymer composition according to any one of claims 1 to 5, wherein the halogenated polymer is a PVC resin having about 57% by weight of chlorine.

7. The halogenated polymer composition according to any one of claims 1 to 6, wherein the halogenated polymer is a CPVC resin having about 64 to 68% by weight of chlorine.

8. A pipe or pipe fitting comprising a halogenated polymer (e.g., PVC, CPVC) composition according to any one of claims 1 to 7.

9. A pipe or pipe fitting according to claim 7, satisfying cell class 23447 to 24448.

10. A pipe or pipe fitting according to claim 7, satisfying cell class 12444 to 14454.

11. A method for stabilizing a halogenated polymer composition, comprising using a barbiturate derivative in the composition.

Images