WO2009053959A2

WO2009053959A2 - Pvc sheets or articles with high heat distortion temperature

Info

Publication number: WO2009053959A2
Application number: PCT/IL2007/001489
Authority: WO
Inventors: Reuven Hugi
Original assignee: Palram Industries (1990) Ltd.
Priority date: 2007-10-23
Filing date: 2007-12-03
Publication date: 2009-04-30
Also published as: WO2009053959A3

Abstract

A polyvinyl chloride (PVC) composition is provided, comprising an epoxy system, with a heat distortion temperature (HDT) of above 65°C. In an embodiment of the invention the PVC is a rigid PVC. In an embodiment of the invention, the PVC resin is at K value, of between 55 and 70. In an embodiment of the invention, the rigid polyvinyl chloride composition is in the form of an article, sheet, pipe, coating or film.

Description

PVC SHEETS OR ARTICLES WITH HIGH HEAT DISTORTION TEMPERATURE

BACKGROUND OF THE INVENTION

Polyvinyl chloride, ("PVC"), is an established synthetic resin with numerous applications, including components for the construction industry such as house sidings and window frames, water pipes, toys, and various household articles. PVC is a hard and brittle resin, which normally is not used as such but is compounded with processing aids, plasticizing polymers and/or liquid plasticizers, and stabilizers, which improve its process ability and performance. Commercially available compounded rigid PVC has an HDT (heat distortion temperature) of only about 60⁰C. Some articles, where rigid PVC either is, or could be used, such as building components, appliances and computer housings at certain periods of the year are subjected to intense heat caused either by their exposure to the sun, or by the operation of the equipment housed therein.

PVC offers a considerable price advantage over other engineering resins, but its use as a structural material has been rather limited because of its low HDT. Last year/in the past years an intense effort was made in the industry to increase the PVC HDT but the methods of increasing its HDT frequently also lower its impact resistance below acceptable limits.

U.S. Pat. No. 5,502,111 discloses a process for the manufacture of a polyvinyl chloride composition, having an improved heat distortion temperature comprising blending at a temperature set within a range of about 150⁰C -220⁰C, polyvinyl chloride with a complementary amount of a polymer blend, comprising a matrix and a dispersed phase, consisting of a dispersed phase of an imidized acrylic resin and a third polymer.

U.S. Pat. No. 4,255,322 to Kopchik discloses blends of PVC with polyglutarimides, which preferably also contain a third polymer serving as an impact modifier. The patentee determined that PVC and polyglutarimides are compatible, and also that the blends have improved HDT's. The polyglutarimides themselves, also known as imidized acrylic resins or imides of polyacrylic acids, were already described by Graves in U.S. Pat. No. 2,146,209, Schroeder in U.S. Pat. No. 3,284,425, Barabas et al. in U.S. Pat. No. 4,169,924, and Kopchik, U.S. Pat. No. 4,246,374. Certain details of the experimental work described in the Kopchik '322 patent are unclear. It is, therefore, not possible to determine by reading the examples of that patent how the components of the final compositions were blended together, although it appears that this was always done in one step. Furthermore, the properties of the blends of Example 7 of that patent, which were supposed to be given in Table III, are not shown/given there or anywhere else.

U.S. Pat. No. 4,595,727 to Doak improves on Kopchik by employing a rubber-modified PVC, rather than blends containing a separate elastomeric impact modifier. Doak reports an HDT for a blend of rubber-modified PVC with 30% of polyglutarimide of 88°C. When the amount of poiyglutarimide is increased to 60%, the HDT is increased to 105⁰C.

U.S. Pat. No. 3,629,170 to Yamanouchi et al. also discloses improved PVC compositions. The improvement is obtained by solution-blending PVC with a polysulfone resin and evaporating the solvent. This reference does not report the HDT but only the Vicat softening temperature of the resulting blends; but, even if an improvement is obtained, it is clear that solution blending is not a practical industrial way of making polymer blends. In any event, since polysulfones are incompatible with PVC, it is not expected that a significant HDT improvement could be obtained in this way.

All of the above described references relate to an invention in which high amount of additives are required for an increase in HDT. This causes a change in the other properties of the rigid PVC and also is not commercially effective.

There is, therefore a need for rigid PVC compositions with a small amount of thermosetic additive that will not change the properties of the PVC.

SUMMARY OF THE INVENTION

In an embodiment of the invention, a polyvinyl chloride (PVC) composition is provided, comprising an epoxy system, with a heat distortion temperature (HDT) of above 65°C. In an embodiment of the invention, a rigid polyvinyl chloride (PVC) composition is provided comprising an epoxy system and having a heat distortion temperature (HDT) of above 75°C. In an embodiment of the invention the PVC is a rigid PVC. In an embodiment of the invention, the PVC resin is at K value, of between 55 and 70. In an embodiment of the invention, the rigid polyvinyl chloride composition is in the form of an article, sheet, pipe, coating or film.

In an embodiment of the invention, there is provided an industrial extrusion, injection molding, or press practical process for producing rigid PVC compositions with an inter-penetration network made of epoxy system in which the composition has improved HDT values. In some embodiments of the invention, the rigid polyvinyl chloride (PVC) article, sheet, pipe, coating or film is manufactured from a dry PVC blend and at least a heat stabilizer, a processing aid, a lubricant and an impact modifier.

In some embodiments of the invention, dry PVC blend also comprises at least (any of a UV stabilizer, color, filler, anti-static agent or foaming agent.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates the method of measuring heat distortion temperature.

Figure 2 summarizes the results for Δ yellow index measurement before and after exposure to Xenon lamp, in rigid PVC sheets having improved HDT and includes a UV absorber, according to the composition presented in Example 3.

Figure 3 summarizes the results for the Rheology test (185°C, 60 rpm) of 1) PVC dry blend based on tin; 2) PVC dry blend based on tin and Epoxy system 2%; and 3) PVC dry blend based on CaZn and Epoxy system 2%.

DESCRIPTION OF DETAILED EMBODIMENTS

In the following description, various aspects of the present invention will be described. For explanation purposes, specific configurations and details are set forth in order to provide a thorough understanding of the present invention. However, it will also be apparent to one skilled in the art that the present invention may be practiced without the specific details presented herein. Furthermore, well-known features may be omitted or simplified in order not to obscure the present invention.

In an embodiment of the invention, a polyvinyl chloride (PVC) composition is provided comprising a thermoset system, wherein the composition has a heat distortion temperature of above 65⁰C. In some embodiments of the invention, the PVC is a rigid PVC. In another embodiment of the invention, the heat distortion temperature is above 70⁰C. In another embodiment of the invention, the heat distortion temperature is above 75⁰C. In another embodiment of the invention, the heat distortion temperature is above 80⁰C. In another embodiment of the invention, the heat distortion temperature is above 85⁰C. In an embodiment of the invention, the thermoset system is an epoxy, polyamide, or polyester system.

In an embodiment of the invention, the thermoset system forms an inter-penetration network in the rigid PVC.

In an embodiment of the invention the rigid PVC is in the form of an article. The term "article" also includes but is not limited to sheet, pipe, coating or film.

In an embodiment of the invention, there is provided a polyvinyl chloride (PVC) composition comprising an epoxy system wherein the composition has a heat distortion temperature of above 65°C. In some embodiments of the invention the PVC is a rigid PVC. In another embodiment of the invention, the heat distortion temperature is above 70⁰C. In another embodiment of the invention, the heat distortion temperature is above 75⁰C. In another embodiment of the invention, the heat distortion temperature is above 80⁰C. In another embodiment of the invention, the heat distortion temperature is above 85⁰C.

In an embodiment of the invention, the PVC resin is at K value between 55 to 70. In another embodiment of the invention, the PVC resin is at K value between 55 to 57. In another embodiment of the invention, the PVC resin is at K value between 57 to 60. In another embodiment of the invention, the PVC resin is at K value between 60 to 63. In another embodiment of the invention, the PVC resin is at K value between 63 to 67. In another embodiment of the invention, the PVC resin is at K value between 67 to 70

In an embodiment of the invention, a rigid PVC articles, is provided, made by extrusion, in which a dry PVC blend is blended with an epoxy system. In an embodiment of the invention, the epoxy system forms an inter-penetration network in the rigid PVC. In an embodiment of the invention, the epoxy system forms an inter-penetration network in the PVC composition.

The functional additives used in the PVC materials include heat stabilizers, lubricants, and in the case of flexible PVC, plasticizers.

Optional additives include a range of substances which may be at least one of any of the following: a processing aid, impact modifier, thermal modifier, UV stabilizer, flame retardant, mineral filler, pigment, biocide, or a blowing agent. The increase in the invention's heat distortion temperature of the PVC composition leads to an increase in the stability and elastic modulus of the resulting rigid PVC article, film, pipe, sheet and the like.

The term "polyvinyl chloride", as used herein, means neat polyvinyl chloride. Since the usual commercial polyvinyl chloride resin or composition contains processing aids, plasticizers, stabilizers, and possibly other additives, the amount of polyvinyl chloride in commercial polyvinyl chloride resin or composition is less than 100%.

In some embodiments of the invention, the rigid polyvinyl chloride (PVC) article, sheet, pipe, coating or film is manufactured from a PVC resin and at least a heat stabilizer, processing aid, lubricant and/or an impact modifier.

In some embodiments of the invention, dry PVC blend also comprises at least any of UV stabilizer, color, filler, anti-static agent or foaming agent.

As used herein, the term "heat stabilizer" is intended to mean a compound required to prevent the decomposition of the PVC by heat and shear during processing. Heat stabilizers can also enhance the PVCs resistance to daylight, and to weathering and heat ageing. In addition, heat stabilizers have an important influence on the physical properties of the PVC and the cost of the formulation. The choice of heat stabilizers depends on a number of factors including the technical requirements of the PVC product, regulatory approval requirements and cost. The main heat stabilizers are usually combined with co-stabilizers, which are organic materials, such as polyols, epoxidised esters, and phosphates. Heat stabilizers create a synergetic effect between the additives. In some embodiments of the invention, the UV stabilizer is benzotriazole, benzophenone, HALS (Hindered Amine Light Stabilizers), oxanilides. Further, heat stabilizer includes, but not limited to, calcium zinc, lead salts such as tri-basic lead sulphate, di-basic lead phosphate, normal lead stearate, di-basic lead phthalate, di-basic lead stearate, organotins such as thio, carboxylates (based on methyl, butyl or octyl groups) butyl tin maleate, calcium/zinc salts of fatty acids, barium/zinc compounds or tin or cadmium or organic base stabilizer (OBS) or any combination thereof.

As used herein, the term "processing aid" is intended to mean processing aid including, but not limited to, high molecular weight acrylic (acrylic polymers) and the like.

In some embodiments of the invention, the processing aid is a high molecular weight acrylic. As used herein, the term "lubricant" is intended to mean lubricant, which may be internal, external or combined internal/external lubricants. Internal lubricants, which facilitate movements of polymer chains (fatty alcohols, esters of fatty alcohols), External lubricants, which reduce the frictional resistance between the polymer and the tools (polyethylene wax (oxidates), Fischer-Tropsch oxidates, Fischer-Tropsch hard paraffins). Internal/external lubricants, as a compromise between internal and external effects, may be used in combination with pure external or internal lubricants such as esters of fatty acids, fatty acid diamides. The lubricants make the matrix highly gelatinous.

In some embodiments of the invention, the lubricant may be internal, external or combined lubricant, and is fatty alcohol, dicarboxylic ester, glycerol ester, metal soap, fatty acid ester, ester wax, fatty acid amide hydroxy! fatty acid, fatty acid, paraffin wax or polyethylene wax.

As used herein, the term "impact modifier" is intended to mean a material, especially an elastomer or plastic of a different type, which is added to and incorporated in a plastic compound to improve the impact resistance of the finished product (to resist sudden pulls or shocks.). It is a general term for any additive, usually an elastomer or plastic of different type, incorporated in a plastic compound to improve the impact resistance of finished articles in order to satisfy end-use requirements for rigid applications.

Impact modifiers include, but not limited to, acrylic polymers, MBS (methylmethacrylate- butadiene-styrene), ABS (acrylonitrile-butadiene-styrene), EVA (ethylene-vinyl acetate copolymers), polyethylene and CPE (chlorinated polyethylene) for outdoor applications, and the like.

In some embodiments of the invention, the color is TiO₂ or any other pigment organic or inorganic or dye

In some embodiments of the invention, the filler is calcium carbonate, or talc.

In some embodiments of the invention, the weight of the heat stabilizer is between 0.1 to 5 PHR (the term "PHR" refers in the application to parts per hundred parts of PVC resin).

In some embodiments of the invention, the weight of the processing aid is between 0.1 to 5 PHR.

In some embodiments of the invention, the weight of the lubricant is between 0.1 to 5 PHR. In some embodiments of the invention, the weight of the impact modifier is between 0.1 to 20% per weight of the PVC.

In some embodiments of the invention, the Epoxy system is a thermosetic system which includes the following: epoxy resins (monomers or oligomers) that may be in the form of a powder, or in the form of thick, clear or yellow liquids. Examples for epoxy resins are without limitation: the diglycidyl ether of bisphenol A (DGEBA), novolac resins, cycloaliphatic epoxy resins, brominated resins, epoxidized olefins, epoxy phenolic, EponR and EpikoteR. The

Epoxy system also includes a curing agent. In an embodiment of the invention the system may further include a catalytic curing agent.

The Epoxy system may also include a curing agent that reacts with epoxy resin monomers to form epoxy products. Examples for curing agents include without limitation: Aliphatic amines such as triethylenetetramine (TETA) and diethylenetriamine (DETA); Aromatic amines, including diaminodiphenyl sulfone (DDS) and dimethylaniline (DMA); Anhydrides such as phthalic anhydride and nadic methyl anhydride (NMA); Amine/phenol formaldehydes such as urea formaldehyde and melamine formaldehyde; Catalytic curing agents such as tertiary amines and boron trifluoride complexes. Diluents and solvents may be used to dilute or thin epoxy resins. Diluents are usually clear liquids. Some examples are without limitation: Glycidyl ethers (reactive diluents) such as n-butyl glycidyl ether (BGE), isopropyl glycidyl ether (IGE) and phenyl glycidyl ether (PGE); organic solvents such as toluene (toluol), xylene (xylenol), acetone, methyl ethyl ketone (MEK), 1 ,1 ,1-trichloroethane (TCA), and glycol ethers. Fillers may be added to give bulk and body to the epoxy products. The fillers may be in the form of a powder or fibers such as, but without being limited to sand, clay, calcium carbonate, fiberglass, asbestos, or silica.

In some embodiments of the invention, the weight of the epoxy system is between 0.1 to 10% of the weight of the dry PVC blend. It is noted that the amount varies between the different types of epoxy.

In some embodiments of the invention, the weight of the epoxy system is between 0.1 to 10% of the weight of the dry PVC blend.

In some embodiments of the invention, the weight of the epoxy system is between 1 to 3% of the weight of the dry PVC blend.

In some embodiments of the invention, the weight of the epoxy system is approximately 2% of the weight of the dry PVC blend. In some embodiments of the invention, the PVC blend comprising an epoxy system is exposed to curing treatment in order to obtain a rigid article, sheet, pipe, coating or film. The curing treatment may be conducted by an exposure to external heat such as in an oven or by being exposed to the sun. The curing treatment period may last a few hours or by being exposed to the sun, several weeks.

In some embodiments of the invention, the rigid PVC is manufactured in a process containing a curing procedure.

In some embodiments of the invention, the curing step is exposure to external heat in an oven, exposure to the sun, or combination thereof.

In some embodiments of the invention, the temperature of the curing by exposure to external heat in an oven is between 20-80⁰C.

In some embodiments of the invention, the combined time period for the curing is between 10 minutes to 1 month. In some embodiments, the curing may be for 1-7 days. In some embodiments, the curing may be for 1-7 days at a high temperature (above 40⁰C). In some embodiments, the curing may be for 1-7 days in high temperature (above 50⁰C). In some embodiments the curing may be for 1-7 days at a high temperature (about 60⁰C). In some embodiments, the curing may be for 1-7 days at a high temperature (above 60⁰C).

In some embodiments of the invention, an accelerator or a catalyst (or a double or triple amount of accelerator) is added for reducing the curing time.

The plastic films, pipes, sheets, coating and articles of the present invention are advantageously employed for applications that require higher temperature resistance, e.g., walls, sheets for roofing, hand rails, door handles, cladding, profiles for windows, rain and water systems, pipes, etc. The sheets, coating, films, pipes and articles of the present invention are used for example in households, gardening, public institutions, ventilation systems, air cleaning and air conditioning systems and waste disposal systems. Rigid PVC articles exposed to outdoor weathering that may have higher temperature resistance of the present invention are, for example, waste containers, swimming pool equipment, outdoor swing set equipment, slides and the like, sheets for roofing and stadium seats. This invention is now illustrated by the following examples of certain representative embodiments thereof, where all parts, proportions, and percentages are by weight unless otherwise indicated.

EXAMPLES

The objective of the experiments conducted was to manufacture a rigid PVC formulation comprising an epoxy system.

The heat distortion temperature was measured as follows: a rod made from the rigid PVC measuring 127X13X3 mm, was placed in a hot oil bath. The temperature at which a test specimen deflects 0.25 mm when loaded in 3-point bending at a specified maximum outer fiber stress. Deflection temperature is used to determine short-term heat resistance. A test specimen is loaded in 3-point bending in the edgewise direction. Outer fiber stresses used for testing are 0.455 MPa (66 psi) and 1.82 MPa (264 psi). The temperature is increased at 2°C/minutes until the specimen deflects 0.25 mm (0.010 in). Figure 1 illustrates the heat method of measuring the heat distortion temperature.

The PVC rod was cut from a sheet made by blending the PVC either with or without the epoxy system in the extruder, heating the blend and running it through the extruder.

The dry PVC blend used in the examples as a control is a PVC formulation including a heat stabilizer, processing aid, lubricant and an impact modifier but without an epoxy system. The formulation is as follows (in terms of parts per 100 parts of PVC): PVC - 100, heat stabilizer (based on liquid tin)- 2.3, processing aid - 0.8, lubricant - 1.45, impact modifier - 6.0 and color (TiO₂) - 11.0. In Example 3 the heat stabilizer was changed to CaZn in order to assess the effect of CaZn on the HDT.

Example 1

Improved HDT in PVC sheets with an epoxy system based on maleic anhydride (MA) and pyromellitic dianhydride (PMDA)

The results set forth in Table 1 represent a formula of epoxy based Maleic anhydride (MA), Pyromellitic dianhydride (PMDA) and epoxy resin (EPR496) with MW of 400.

The composition was made as follows: MA/PMDA in a ratio of 3/2 by weight (heated and blended at 6O⁰C for five minutes) was used. Epoxy resin was added at a ratio of 0.8 (anhydride/epoxy 8/10), and the composition was heated and blended for an additional five minutes. The Epoxy MA/PMDA composition was added to the dry PVC blend in the high-speed mixer for five minutes. The mixture was allowed to cool and was subjected to the laboratory scale extruder for producing a 1.5 mm thickness sheet. The results set forth in Table 1 below showed that curing (heat treatment) increases the heat distortion temperature. Additionally, measurement over a period of time showed that the heat distortion temperature (HDT) increases when the composition is allowed to age. In order to optimize the mixture's properties, it is recommended to add the epoxy blend after the heat stabilizer.

Table 1

Example 2 Rigid PVC sheets, based on phenolic epoxy system, with improved HDT

Epoxy phenolic (Epoxy-Formula-I) was added as a white powder. Two percent of epoxy phenolic was added to the Dry PVC Blend in the mixer at 70⁰C.

The epoxy formula I contained the following ingredients (in parts per hundred parts of epoxy resin): epoxy resin- 100, titanium dioxide (color) - 44.6, accelerator - 0.78, silica - 23.41 , hardener - 31.0, flow control agent based on polyacrylate - 1.5 and lubricant - 22.5.

The post curing treatment lasted at 60⁰C for 12, 36 hours and five days.

The results presented in Ta,ble 2 show that the Epoxy Formula I increased the HDT of the product. Further, as can be seen, post curing treatment of 5 days increased the heat distortion temperature (HDT) to 77⁰C. The mechanical properties (data no shown) remained unchanged. Table 2

HDT test was performed according to ASTMD 648

Example 3 Rigid PVC sheets with improved HDT with a UV stabilizer

Epoxy phenolic (Epoxy Formula 3) was added as a white powder including a triple amount of an accelerator (in comparison to the amount in Epoxy Formula 1) in order to reduce the curing time.

The Epoxy Formula 3 contained the following ingredients (in parts per hundred parts of epoxy resin): epoxy resin - 100, titanium dioxide (color) - 44.6, accelerator - 2.34, silica 23.41 , hardener - 31 , flow control agent based on polyacrylate - 1.5, lubricant- 22.5.

The following formulations were tested with a Dry PVC Blend, Dry PVC Blend and Epoxy Formula 1 , Dry PVC Blend and Epoxy Formula 3 with and without UV stabilizers which are Lowilite 94 (Λ/,Λ/-Bis(2,2,6,6-tetramethyl-4-piperidinyl)-1 ,6-hexanediamine polymer with 2,4,6- trichloro-1 ,3,5-triazene and 2,4,4-timethyl-1 ,2-pentanamine) and/or Uvinul 3035 (ethyl-2- cyano-3,3-diphenyl acrylate):

1. 100% Dry PVC Blend.

2. 98% Dry PVC Blend + 2% Epoxy Formula 3.

3. 98% Dry PVC Blend + 2% Epoxy Formula 1.

4. 97% Dry PVC Blend + 2% Epoxy Formula 3+ 1 % Uvinul 3035.

5. 97% Dry PVC Blend + 2% Epoxy Formula 3 + 0.5% Uvinul 3035 + 0.5% Lowilite 94.

6. 97% Dry PVC Blend + 2% Epoxy Formula 3+ 1 % Lowilite 94

The HDT tests were performed after post curing at 6O⁰C for 12, 36 hours and three days. The UV resistance tests were performed in the following conditions: 2000 hours in the ultraviolet degradation using Xenon lamp. Table 3 summarizes the results for color measurement and yellow index measurement before and after exposure to Xenon lamp. Figure 2 summarizes the results for yellow index measurement before and after exposure to Xenon lamp.

Table 3

• Color was measured according to ASTME 308(85), in MiniScan XE in geometry D65/10⁰. Yellow index was measured according to ASTM E-313-05, in MiniScan XE in geometry D65/10⁰.

This experiment clearly shows that Lowilite 94 compensates for the UV-resistance decrease caused by the addition of the epoxy system.

Table 4 summarizes the results for HDT measurement of these samples. The results show that addition of 2% epoxy system and 1 % UV stabilizer, which is Lowilite 94 can increase the HDT to 77°C after 5 days of curing at 60°C. Furthermore, using Lowilite 94 together with epoxy improved the UV resistance without impairing the HDT.

Table 4

• HDT test was performed according to ASTMD 648

Example 4 Dry PVC Blend based on CaZn as heat stabilizer with and without an Epoxy system

This experiment was performed in order to test the effect of the conversion of a liquid tin stabilizer in the Dry PVC Blend into CaZn will improve the HDT. The formulation contained Dry PVC Blend based on CaZn as a heat stabilizer with and without Epoxy Formula 3. The formulation ingredients are set forth in Table 5.

Table 5

All the ingredients except for TiO₂ were inserted into the mixer and mixed. The TiO₂ was added at 100⁰C and the mixture was mixed for an additional 40 seconds.

The HDT tests were performed after post curing at 6O⁰C, for 24 hours, and three and five days.

Table 6 summarized the results for HDT measurement of the samples.

Table 6

HDT test was performed according to ASTMD 648 Table 7 summarized the results for color measurement and yellow index measurement

Table 7

Table 8 and Figure 3 summarized the results for the Rheology test (185°C, 60 rpm)

Table 8

As can be seen, Dry PVC Blend based on CaZn with an epoxy system caused a dramatic increase of HDT to 81⁰C without significant influence on color and rheology.

Claims

What is claimed is:

1. A rigid polyvinyl chloride (PVC) article comprising a thermoset system and having a heat distortion temperature (HDT) of above 65°C.

2. The rigid polyvinyl chloride (PVC) article, wherein the thermoset system is an epoxy system.

3. The rigid PVC article of claim 1 , wherein the HDT is above 75⁰C.

4. The rigid polyvinyl chloride (PVC) article of claim 1 , manufactured from dry PVC blend comprising a PVC resin at K value between 55 and 70.

5. A rigid polyvinyl chloride (PVC) article as claimed in claim 4, wherein the dry PVC blend also comprises a heat stabilizer, processing aid, and a lubricant.

6. The rigid PVC article of claim 5, wherein the heat stabilizer is CaZn.

7. A rigid polyvinyl chloride (PVC) article as claimed in claim 5, wherein the dry PVC blend also comprises at least one of either a UV stabilizer, color, filler, antistatic agent, impact modifier or a foaming agent.

8. A rigid polyvinyl chloride (PVC) article as claimed in claim 2, wherein the epoxy system comprises an epoxy phenolic.

9. A rigid polyvinyl chloride (PVC) article as claimed in claim 4, wherein the weight of the epoxy system is between 0.1 to 10% per weight of the dry PVC blend.

10. A rigid polyvinyl chloride (PVC) article as claimed in claim 4, wherein the weight of the epoxy system is between 1 to 5% of the weight of the dry PVC blend.

11. A rigid polyvinyl chloride (PVC) article as claimed in claim 4, wherein the weight of the epoxy system is approximately 2% of the weight of the dry PVC blend.

12. A rigid polyvinyl chloride (PVC) article as claimed in claim 2, wherein the epoxy system comprises an epoxy resin and a curing agent.

13. The rigid PVC article of claim 1 or 2, wherein the rigid PVC is manufactured by extrusion, injection molding, or a press.

14. The rigid PVC article of claim 13, wherein the manufacture process comprises a step of post curing treatment.

15. The rigid PVC of claim 14, wherein the step of curing is by exposure to external heat in an oven, exposure to the sun, or a combination thereof.

16. The rigid PVC of claim 14, wherein the temperature of the oven is between 20- 8O⁰C.

17. The rigid PVC of claim 14, wherein the time period for the post curing stage is between 1 and 7 days.

18. A PVC composition blended with an epoxy system, wherein the epoxy system forms an inter-penetration network in the PVC.

19. The rigid PVC article of claim 1 , wherein the thermoset system forms an inter- penetration network in the rigid PVC article.

20. The rigid PVC article of claim 2, wherein the epoxy system forms an inter- penetration network in the rigid PVC article.