CA2444711A1 - Antimicrobial injection-molded components and method for producing the same - Google Patents
Antimicrobial injection-molded components and method for producing the same Download PDFInfo
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- CA2444711A1 CA2444711A1 CA 2444711 CA2444711A CA2444711A1 CA 2444711 A1 CA2444711 A1 CA 2444711A1 CA 2444711 CA2444711 CA 2444711 CA 2444711 A CA2444711 A CA 2444711A CA 2444711 A1 CA2444711 A1 CA 2444711A1
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- 230000000845 anti-microbial effect Effects 0.000 title claims abstract description 58
- 238000004519 manufacturing process Methods 0.000 title description 4
- 239000000654 additive Substances 0.000 claims abstract description 39
- 230000000996 additive effect Effects 0.000 claims abstract description 39
- 239000000203 mixture Substances 0.000 claims abstract description 37
- 239000002991 molded plastic Substances 0.000 claims abstract description 27
- 239000004599 antimicrobial Substances 0.000 claims abstract description 18
- XEFQLINVKFYRCS-UHFFFAOYSA-N Triclosan Chemical compound OC1=CC(Cl)=CC=C1OC1=CC=C(Cl)C=C1Cl XEFQLINVKFYRCS-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000000835 fiber Substances 0.000 claims abstract description 7
- 238000009472 formulation Methods 0.000 claims description 31
- 229920005992 thermoplastic resin Polymers 0.000 claims description 23
- 239000011347 resin Substances 0.000 claims description 16
- 229920005989 resin Polymers 0.000 claims description 16
- 229920002292 Nylon 6 Polymers 0.000 claims description 12
- 238000000465 moulding Methods 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 11
- 229920001778 nylon Polymers 0.000 claims description 10
- 239000004677 Nylon Substances 0.000 claims description 9
- -1 polyethylene Polymers 0.000 claims description 9
- 229920000139 polyethylene terephthalate Polymers 0.000 claims description 6
- 239000005020 polyethylene terephthalate Substances 0.000 claims description 6
- 239000004952 Polyamide Substances 0.000 claims description 5
- 229920002647 polyamide Polymers 0.000 claims description 5
- 230000000813 microbial effect Effects 0.000 claims description 4
- 239000004698 Polyethylene Substances 0.000 claims description 2
- 239000004743 Polypropylene Substances 0.000 claims description 2
- 239000006229 carbon black Substances 0.000 claims description 2
- 229920000573 polyethylene Polymers 0.000 claims description 2
- 239000002952 polymeric resin Substances 0.000 claims description 2
- 229920001155 polypropylene Polymers 0.000 claims description 2
- 239000004814 polyurethane Substances 0.000 claims description 2
- 229920002635 polyurethane Polymers 0.000 claims description 2
- 239000004800 polyvinyl chloride Substances 0.000 claims description 2
- 229920000915 polyvinyl chloride Polymers 0.000 claims description 2
- 229920003002 synthetic resin Polymers 0.000 claims description 2
- 239000002033 PVDF binder Substances 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 claims 1
- 229920013716 polyethylene resin Polymers 0.000 claims 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims 1
- 238000001746 injection moulding Methods 0.000 abstract description 10
- 239000000088 plastic resin Substances 0.000 abstract description 10
- 239000004033 plastic Substances 0.000 abstract description 6
- 229920003023 plastic Polymers 0.000 abstract description 6
- 239000003365 glass fiber Substances 0.000 abstract description 4
- 238000000151 deposition Methods 0.000 abstract description 2
- 239000011342 resin composition Substances 0.000 abstract description 2
- 239000000047 product Substances 0.000 description 40
- 238000012360 testing method Methods 0.000 description 10
- 150000001875 compounds Chemical class 0.000 description 7
- 230000000704 physical effect Effects 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- 239000000645 desinfectant Substances 0.000 description 5
- 241000894006 Bacteria Species 0.000 description 4
- 241000233866 Fungi Species 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 201000010099 disease Diseases 0.000 description 4
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 4
- 244000052769 pathogen Species 0.000 description 4
- 230000003115 biocidal effect Effects 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 230000003068 static effect Effects 0.000 description 3
- 239000004594 Masterbatch (MB) Substances 0.000 description 2
- 241000700605 Viruses Species 0.000 description 2
- 230000001580 bacterial effect Effects 0.000 description 2
- 239000003139 biocide Substances 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 description 2
- 239000011152 fibreglass Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000009863 impact test Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000001717 pathogenic effect Effects 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 239000006057 Non-nutritive feed additive Substances 0.000 description 1
- 229920002302 Nylon 6,6 Polymers 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000002599 biostatic effect Effects 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000012864 cross contamination Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 230000002538 fungal effect Effects 0.000 description 1
- 230000009036 growth inhibition Effects 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 150000002989 phenols Chemical class 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 230000035755 proliferation Effects 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000012815 thermoplastic material Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 229960003500 triclosan Drugs 0.000 description 1
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- Compositions Of Macromolecular Compounds (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
- Agricultural Chemicals And Associated Chemicals (AREA)
Abstract
The invention relates to injection-molded plastic products having an antimicrobial additive incorporated into the plastic resin from which the injection-molded plastic products are formed. A preferred antimicrobial additive comprises 5-chloro-2-(2,4-dichlorophenoxy) phenol. The injection-molded plastic products are formed by selecting an antimicrobial additive and an antimicrobial additive carrier system compatible with a plastic resin, combining the carrier system with the selected antimicrobial additive, incorporating the antimicrobial additive/carrier system into the plastic resin, depositing the plastic resin composition, including glass fibers or other high modulus fibers if desired, within the feed system of an injection-molding process and injecting the resin composition into a desired product-forming mold to form an injection-molded antimicrobial plastic product.
Description
Atty/Docket No. 921184-913100 ANTIMICROBIAL INJECTION-MOLDED COMPONENTS AND METHOD
FOR PRODUCING THE SAME
FIELD OF THE INVENTION This invention relates generally to antimicrobial, injection-molded plastics, and more particularly to injection-molded plastic products having antimicrobial compounds or chemicals dispersed within the plastic resin that forms the products.
BACKGROUND OF THE INVENTION
Injection-molded plastic products are widely used in numerous consumer products to provide a sturdy plastic structure having a desirable surface appearance. For example, injection-molded plastic products include furniture and furniture parts which are used in homes, hotels, hospitals, restaurants, schools and other residential or commercial environments. Merely both parties contacting the same instrumentality before any steps can be taken to protect oneself can transmit several diseases from the carrier to another person. Hospital personnel are especially at risk from readily transmitted diseases from handling objects, such as furniture, wherein various viruses, fungi, and disease-causing bacteria have been able to subsist. Food service personnel put both themselves and consumers at risk from various viruses, fungi, and disease-causing bacteria. In penal institutions, both employees and inmates can be at risk from all of the same items of possible cross contamination. Educational institutions, such as schools and day-care facilities, provide many instrumentalities that may be handled by numerous children and thereby spread microorganisms.
In a more specific example, injection-molded plastic is utilized to form plastic components for seating, namely seat backs and pans, stadium seats, office chairs, chair bases, chair arm supports and position adjustment mechanisms, as well as casters for chairs and other commercial and industrial applications, all of which find use in one or more of the previously described environments. However, the surfaces of these injection-molded plastic products are under constant exposure to bacteria, fungi and microbes that exist in the previously described environments. For example, injection-molded plastic Atty/Docket No. 921184-913100 chair bases, casters and other plastic components are used in hospitals and other environments that are particularly associated with pathogen development and proliferation. The presence of humidity or moisture in these environments, or any environment, is conducive to growth of pathogens. These bacteria, fungi and other pathogens can grow and multiply on the surfaces of the injection-molded plastic based products, and significant levels of microbial contamination can build over time. One proposed method to counter the presence and growth of microbes on the surface of injection-molded products is to apply a disinfectant to the surface, such as by spraying or wiping the surface. Unfortunately, the applied disinfectant provides only temporary removal of the microbes on the surface, but, as previously mentioned, the associated environment is a continuous resource for further contamination. Reapplication of the disinfectant is costly, time consuming, non-durable and only temporarily counters the presence and growth of microbes. Additionally, by applying the disinfectant or other biocide to the surface of the product, a residual of the disinfectant or biocide enters the environment and may negatively impact the environment, especially in a hospital setting.
Therefore, there exists a need for injection-molded plastic products having an antimicrobial agent incorporated therein that exhibit antimicrobial properties, that are free from toxic effect and are durable over the lifespan of the injection-molded plastic product. However, by incorporating an additional material into the injection-molded plastic products, one would expect a diminishment of the physical and mechanical properties of the injection-molded plastic products because a corresponding amount of a mechanical constituent, e.g., glass fiber or polymer resin, would be replaced by the additional material. Further needed are injection-molded plastic products having antimicrobial compounds or chemicals embedded in the plastic resin that have physical and mechanical characteristics similar to injection-molded plastic products that do not have antimicrobial compounds or chemicals embedded in the product.
Atty/Docket No: 921184-913100 SUMMARY OF THE INVENTION
The present invention is directed to injection-molded plastic products having antimicrobial characteristics that inhibit bacterial, fungal, microbial and other pathogen growth and a method for producing the injection-molded plastic products. The antimicrobial agents, compounds or chemicals are embedded in the injection-molded plastic products during manufacturing. Further, the present invention is directed to injection-molded plastic products having antimicrobial compounds or chemicals embedded in the products that have physical and mechanical characteristics similar to injection-molded plastic products that do not have antimicrobial compounds or chemicals embedded in the product. An antimicrobial additive is incorporated into the plastic resin from which injection-molded plastic products are formed, thereby incorporating the antimicrobial agent into the injection-molded plastic products. A preferred antimicrobial additive comprises 5-chloro-2-(2,4-dichlorophenoxy) phenol. Products formed with injection-molded plastic resins include, without limitation, components for seating, namely seat backs and pans, stadium seats, office chairs, chair bases, chair arm supports and position adjustment mechanisms, as well as casters for chairs and other commercial and industrial applications, etc. The injection-molded plastic products are formed by selecting the antimicrobial additive and an antimicrobial additive carrier system compatible with the plastic resin, combining the carrier system with the selected antimicrobial additive, incorporating the antimicrobial additive/carrier system into the plastic resin, depositing the plastic resin composition, including glass fibers or other high modulus fibers if desired, within the feed system of an injection-molding process and injecting the resin composition into a desired product-forming mold to form an injection-molded antimicrobial plastic product.
DETAILED DESCRIPTION OF THE INVENTION
In the most basic form of the invention, an injection-molded article of a thermoplastic material containing an effective amount of an antimicrobial additive is Atty/Docket No. 921184-913100 provided. A molding formulation comprising a thermoplastic resin and an antimicrobial additive formulation are blended and injection-molded to form the article. The thermoplastic resin is preferably selected from the group consisting of polyamide thermoplastic resins (e.g. nylon 6, nylon 6,6), polyethylene thermoplastic resins, polyurethane thermoplastic resins, polypropylene thermoplastic resins, polyvinyl chloride thermoplastic resins and blends of the foregoing. Nylon resins, or polyamides, are preferred and are a class of thermoplastic resins generally known to have good mechanical strength, abrasion resistance, and toughness. Nylons that are of commercial importance are prepared by the conventional melt polymerization process and include the most preferred resin, nylon 6, which is made by the polymerization of caprolactam. The thermoplastic resin may be modified by inclusion of processing aids, colorants or mechanical modifiers such as glass fibers or other high modulus fibers known to those of skill in the art.
The antimicrobial formulation comprises an antimicrobial additive and preferably further comprises a carrier resin. The antimicrobial additive, which is non-toxic, and free of heavy metals, is preferably a chlorinated phenol, such as 5-chloro-2-(2,4 dichlorophenoxy) phenol, also known as triclosan. Other chemical compounds having known antimicrobial, biocidal or biostatic tendencies may also be employed.
Preferably, the antimicrobial additive is pre-blended with a suitable carrier resin, such as a polyester and more preferably polyethylene terephthalate (PET). A preferred antimicrobial additive is IRGAGUARD~ B 1325 (25 Wt. % 5-chloro-2-(2,4 dichlorophenoxy) phenol in a PET carrier resin) available from Ciba Specialty Chemicals Corporation, Tarrytown, New York, USA. The antimicrobial additive preferably comprises from about 0.1 wt.
to about 1.25 wt. % of the total product composition.
The invention is more specifically directed to injection-molded nylon products having an antimicrobial additive embedded therein which imparts antimicrobial characteristics to the product. In particular, the products include furniture parts, and more particularly components for seating, namely seat backs and pans, stadium seats, office chairs, chair bases, chair arm supports and position adjustment mechanisms, as well as casters for chairs and other commercial and industrial applications for use with Atty/Docket No.-921184-913100 commercial furniture. Surprisingly, the present inventors have found that the inclusion of 0.1 wt. % to about 1.25 wt. % of antimicrobial additive according to the present invention does not substantially degrade the physical, mechanical and surface appearance properties of the resultant product, when compared to a similar product that does not include the antimicrobial additive. Incorporating an appropriate amount of antimicrobial additive into the nylon resin is important. Since the use of the antimicrobial additive displaces a portion of the nylon resin from the injection-molding formulation, it would appear that use of an antimicrobial additive would cause a proportional loss in physical properties to be realized in the final product. Surprisingly, this is not the case. The antimicrobial additive incorporated into the injection-molded nylon products surprisingly exhibits similar physical properties to like products, despite the displacement of nylon resin by the antimicrobial additive.
The following examples are presented to further illustrate the invention.
Section 1.01 Example 1 A chair base according to the present invention was injection-molded using a conventional injection molding process. The injection-molding formulation was as follows: 39 wt. % unfilled black impact modified nylon 6 having an average specific gravity of 1.13 (ASTM D792), an average notched izod rating of 1.5 ft-Ib/in (ASTM
D256), an average tensile yield strength of 10,500 psi (ASTM D638) and an average flexural modulus of 400,000 psi (ASTM D790) such as that commercially available from The Matrix Group, Evansville, Indiana, USA; 57.5 wt. % glass filled nylon 6 having an average fiberglass content of 43 %, an average specific gravity of 1.49 (ASTM
D792), an average notched izod rating of 2.0 ft-lb/in (ASTM D256), an average tensile yield strength of 243,500 psi (ASTM D638) and an average flexural modulus (tangent) of 1,500,000 psi (ASTM D790) such as that commercially available from The Matrix Group under the product name FP62E43; 2 wt. % black masterbatch (50 wt. % carbon black in a polpropylene resin having an average particle size of 60 millimicrons) such as Tech Master commercially available from L.C.Plastics Inc,Montreal, Canada; and 1.5 wt.
Atty/Docket No.,921184-913100 IRGAGUARD~ B1325. The formulation was fed into the injection-molding machine and injected into a mold cavity at approximately 490 °F and 60-95 % of the maximum injection pressure.
The resultant product was removed from the mold and cooled.
Two samples of the injection-molded chair base were tested for bacterial growth inhibition. Both samples exhibited desirable inhibition to microbial growth.
The physical properties of the injection-molded chair bases were also measured by taking two samples and performing Static Load and Drop Test testing as per American National Standards Institute/Business and Institutional Furniture Manufacturer's Association (ANSI/BIFMA) requirements, the results of these tests are presented in Table 1.
Table 1 SampleStatic Load Drop Test (ANSI/BIFMA X5.1-2002 - Base (ANSI/BIFMA X5.1-2002 - Drop Test - Test -Static) Dynamic) 1 > 2,500 Ib > 7in 2 > 2,500 Ib > 7in Example 2 A comparative chair base was produced using the same molding formulation, method and apparatus as used for Example l, except no antimicrobial additive was used.
The injection-molding formulation was as follows: 40 wt. % unfilled black impact modified nylon 6; 58 wt. % glass filled nylon 6 having an average fiberglass content of 43%; and 2 wt. % black masterbatch.
Two samples were taken from the comparative chair base and the physical properties were measured as described for Example 1. The results are presented in Table 2.
Atty/Doeket No. 921184-913100 Table 2 Sample Static Load Drop Test (ANSI/BIFMA X5.1-2002(ANSI/BIFMA X5.1-2002 - -Base Test - Static) Dro Test - Dynamic) > 2,500 1b > 7in > 2,500 1b > 7in Surprisingly, the substitution of antimicrobial additive for nylon resin does not degrade the physical properties of the injection-molded nylon product.
Example 3 Injection-molded casters were produced using a standard injection-molding assembly. A caster according to the present invention, denoted Sample No. 1, was produced from an injection-molding formulation comprising: 98.5 wt. % unfilled black impact modified nylon 6 having an average specific gravity of 1.13 (ASTM
D792), an average notched izod rating of 1.5 ft-lb/in (ASTM D256), an average tensile yield strength of 10,500 psi (ASTM D638) and an average flexural modulus of 400,000 psi (ASTM D790) such as that commercially available from The Matrix Group, Evansville, Indiana, USA; and 1.5 wt. % IRGAGUARD~ B 1325. The formulation was injection-molded at a temperature of approximately 516 °F and 80% of the maximum injection pressure. The casters were then removed from the mold and cooled. A
comparative sample, Sample No. 2 was produced using the same process, except that the formulation did not include an antimicrobial additive (100 wt. % unfilled black impact modified nylon 6).
The physical properties of the two samples were measured and the results are provided in Table 3. The impact test was performed by dropping a weight of 30 lbs.
from a height of 5" on the caster wheels and noting whether mechanical failure occurs.
Atty/Docket Nc~. 921184-913100 _g_ Table 3 Sample No. Durability Test Impact Test ANSI/BIFMA (I50 in-Ib.) Draft A ril 2002 1 (inventive) Hard wheels Hard wheels > 100,000 cycles Passed 2 (comparative) Hard wheels Hard wheels > 100,000 cycles Passed Again, it is surprisingly shown that the addition of antimicrobial agent to the injection-molding formulation does not degrade the physical properties of the resultant product.
While the invention has been described in detail for the purpose of illustration, it is understood that such detail is solely for that purpose, and variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the following claims.
FOR PRODUCING THE SAME
FIELD OF THE INVENTION This invention relates generally to antimicrobial, injection-molded plastics, and more particularly to injection-molded plastic products having antimicrobial compounds or chemicals dispersed within the plastic resin that forms the products.
BACKGROUND OF THE INVENTION
Injection-molded plastic products are widely used in numerous consumer products to provide a sturdy plastic structure having a desirable surface appearance. For example, injection-molded plastic products include furniture and furniture parts which are used in homes, hotels, hospitals, restaurants, schools and other residential or commercial environments. Merely both parties contacting the same instrumentality before any steps can be taken to protect oneself can transmit several diseases from the carrier to another person. Hospital personnel are especially at risk from readily transmitted diseases from handling objects, such as furniture, wherein various viruses, fungi, and disease-causing bacteria have been able to subsist. Food service personnel put both themselves and consumers at risk from various viruses, fungi, and disease-causing bacteria. In penal institutions, both employees and inmates can be at risk from all of the same items of possible cross contamination. Educational institutions, such as schools and day-care facilities, provide many instrumentalities that may be handled by numerous children and thereby spread microorganisms.
In a more specific example, injection-molded plastic is utilized to form plastic components for seating, namely seat backs and pans, stadium seats, office chairs, chair bases, chair arm supports and position adjustment mechanisms, as well as casters for chairs and other commercial and industrial applications, all of which find use in one or more of the previously described environments. However, the surfaces of these injection-molded plastic products are under constant exposure to bacteria, fungi and microbes that exist in the previously described environments. For example, injection-molded plastic Atty/Docket No. 921184-913100 chair bases, casters and other plastic components are used in hospitals and other environments that are particularly associated with pathogen development and proliferation. The presence of humidity or moisture in these environments, or any environment, is conducive to growth of pathogens. These bacteria, fungi and other pathogens can grow and multiply on the surfaces of the injection-molded plastic based products, and significant levels of microbial contamination can build over time. One proposed method to counter the presence and growth of microbes on the surface of injection-molded products is to apply a disinfectant to the surface, such as by spraying or wiping the surface. Unfortunately, the applied disinfectant provides only temporary removal of the microbes on the surface, but, as previously mentioned, the associated environment is a continuous resource for further contamination. Reapplication of the disinfectant is costly, time consuming, non-durable and only temporarily counters the presence and growth of microbes. Additionally, by applying the disinfectant or other biocide to the surface of the product, a residual of the disinfectant or biocide enters the environment and may negatively impact the environment, especially in a hospital setting.
Therefore, there exists a need for injection-molded plastic products having an antimicrobial agent incorporated therein that exhibit antimicrobial properties, that are free from toxic effect and are durable over the lifespan of the injection-molded plastic product. However, by incorporating an additional material into the injection-molded plastic products, one would expect a diminishment of the physical and mechanical properties of the injection-molded plastic products because a corresponding amount of a mechanical constituent, e.g., glass fiber or polymer resin, would be replaced by the additional material. Further needed are injection-molded plastic products having antimicrobial compounds or chemicals embedded in the plastic resin that have physical and mechanical characteristics similar to injection-molded plastic products that do not have antimicrobial compounds or chemicals embedded in the product.
Atty/Docket No: 921184-913100 SUMMARY OF THE INVENTION
The present invention is directed to injection-molded plastic products having antimicrobial characteristics that inhibit bacterial, fungal, microbial and other pathogen growth and a method for producing the injection-molded plastic products. The antimicrobial agents, compounds or chemicals are embedded in the injection-molded plastic products during manufacturing. Further, the present invention is directed to injection-molded plastic products having antimicrobial compounds or chemicals embedded in the products that have physical and mechanical characteristics similar to injection-molded plastic products that do not have antimicrobial compounds or chemicals embedded in the product. An antimicrobial additive is incorporated into the plastic resin from which injection-molded plastic products are formed, thereby incorporating the antimicrobial agent into the injection-molded plastic products. A preferred antimicrobial additive comprises 5-chloro-2-(2,4-dichlorophenoxy) phenol. Products formed with injection-molded plastic resins include, without limitation, components for seating, namely seat backs and pans, stadium seats, office chairs, chair bases, chair arm supports and position adjustment mechanisms, as well as casters for chairs and other commercial and industrial applications, etc. The injection-molded plastic products are formed by selecting the antimicrobial additive and an antimicrobial additive carrier system compatible with the plastic resin, combining the carrier system with the selected antimicrobial additive, incorporating the antimicrobial additive/carrier system into the plastic resin, depositing the plastic resin composition, including glass fibers or other high modulus fibers if desired, within the feed system of an injection-molding process and injecting the resin composition into a desired product-forming mold to form an injection-molded antimicrobial plastic product.
DETAILED DESCRIPTION OF THE INVENTION
In the most basic form of the invention, an injection-molded article of a thermoplastic material containing an effective amount of an antimicrobial additive is Atty/Docket No. 921184-913100 provided. A molding formulation comprising a thermoplastic resin and an antimicrobial additive formulation are blended and injection-molded to form the article. The thermoplastic resin is preferably selected from the group consisting of polyamide thermoplastic resins (e.g. nylon 6, nylon 6,6), polyethylene thermoplastic resins, polyurethane thermoplastic resins, polypropylene thermoplastic resins, polyvinyl chloride thermoplastic resins and blends of the foregoing. Nylon resins, or polyamides, are preferred and are a class of thermoplastic resins generally known to have good mechanical strength, abrasion resistance, and toughness. Nylons that are of commercial importance are prepared by the conventional melt polymerization process and include the most preferred resin, nylon 6, which is made by the polymerization of caprolactam. The thermoplastic resin may be modified by inclusion of processing aids, colorants or mechanical modifiers such as glass fibers or other high modulus fibers known to those of skill in the art.
The antimicrobial formulation comprises an antimicrobial additive and preferably further comprises a carrier resin. The antimicrobial additive, which is non-toxic, and free of heavy metals, is preferably a chlorinated phenol, such as 5-chloro-2-(2,4 dichlorophenoxy) phenol, also known as triclosan. Other chemical compounds having known antimicrobial, biocidal or biostatic tendencies may also be employed.
Preferably, the antimicrobial additive is pre-blended with a suitable carrier resin, such as a polyester and more preferably polyethylene terephthalate (PET). A preferred antimicrobial additive is IRGAGUARD~ B 1325 (25 Wt. % 5-chloro-2-(2,4 dichlorophenoxy) phenol in a PET carrier resin) available from Ciba Specialty Chemicals Corporation, Tarrytown, New York, USA. The antimicrobial additive preferably comprises from about 0.1 wt.
to about 1.25 wt. % of the total product composition.
The invention is more specifically directed to injection-molded nylon products having an antimicrobial additive embedded therein which imparts antimicrobial characteristics to the product. In particular, the products include furniture parts, and more particularly components for seating, namely seat backs and pans, stadium seats, office chairs, chair bases, chair arm supports and position adjustment mechanisms, as well as casters for chairs and other commercial and industrial applications for use with Atty/Docket No.-921184-913100 commercial furniture. Surprisingly, the present inventors have found that the inclusion of 0.1 wt. % to about 1.25 wt. % of antimicrobial additive according to the present invention does not substantially degrade the physical, mechanical and surface appearance properties of the resultant product, when compared to a similar product that does not include the antimicrobial additive. Incorporating an appropriate amount of antimicrobial additive into the nylon resin is important. Since the use of the antimicrobial additive displaces a portion of the nylon resin from the injection-molding formulation, it would appear that use of an antimicrobial additive would cause a proportional loss in physical properties to be realized in the final product. Surprisingly, this is not the case. The antimicrobial additive incorporated into the injection-molded nylon products surprisingly exhibits similar physical properties to like products, despite the displacement of nylon resin by the antimicrobial additive.
The following examples are presented to further illustrate the invention.
Section 1.01 Example 1 A chair base according to the present invention was injection-molded using a conventional injection molding process. The injection-molding formulation was as follows: 39 wt. % unfilled black impact modified nylon 6 having an average specific gravity of 1.13 (ASTM D792), an average notched izod rating of 1.5 ft-Ib/in (ASTM
D256), an average tensile yield strength of 10,500 psi (ASTM D638) and an average flexural modulus of 400,000 psi (ASTM D790) such as that commercially available from The Matrix Group, Evansville, Indiana, USA; 57.5 wt. % glass filled nylon 6 having an average fiberglass content of 43 %, an average specific gravity of 1.49 (ASTM
D792), an average notched izod rating of 2.0 ft-lb/in (ASTM D256), an average tensile yield strength of 243,500 psi (ASTM D638) and an average flexural modulus (tangent) of 1,500,000 psi (ASTM D790) such as that commercially available from The Matrix Group under the product name FP62E43; 2 wt. % black masterbatch (50 wt. % carbon black in a polpropylene resin having an average particle size of 60 millimicrons) such as Tech Master commercially available from L.C.Plastics Inc,Montreal, Canada; and 1.5 wt.
Atty/Docket No.,921184-913100 IRGAGUARD~ B1325. The formulation was fed into the injection-molding machine and injected into a mold cavity at approximately 490 °F and 60-95 % of the maximum injection pressure.
The resultant product was removed from the mold and cooled.
Two samples of the injection-molded chair base were tested for bacterial growth inhibition. Both samples exhibited desirable inhibition to microbial growth.
The physical properties of the injection-molded chair bases were also measured by taking two samples and performing Static Load and Drop Test testing as per American National Standards Institute/Business and Institutional Furniture Manufacturer's Association (ANSI/BIFMA) requirements, the results of these tests are presented in Table 1.
Table 1 SampleStatic Load Drop Test (ANSI/BIFMA X5.1-2002 - Base (ANSI/BIFMA X5.1-2002 - Drop Test - Test -Static) Dynamic) 1 > 2,500 Ib > 7in 2 > 2,500 Ib > 7in Example 2 A comparative chair base was produced using the same molding formulation, method and apparatus as used for Example l, except no antimicrobial additive was used.
The injection-molding formulation was as follows: 40 wt. % unfilled black impact modified nylon 6; 58 wt. % glass filled nylon 6 having an average fiberglass content of 43%; and 2 wt. % black masterbatch.
Two samples were taken from the comparative chair base and the physical properties were measured as described for Example 1. The results are presented in Table 2.
Atty/Doeket No. 921184-913100 Table 2 Sample Static Load Drop Test (ANSI/BIFMA X5.1-2002(ANSI/BIFMA X5.1-2002 - -Base Test - Static) Dro Test - Dynamic) > 2,500 1b > 7in > 2,500 1b > 7in Surprisingly, the substitution of antimicrobial additive for nylon resin does not degrade the physical properties of the injection-molded nylon product.
Example 3 Injection-molded casters were produced using a standard injection-molding assembly. A caster according to the present invention, denoted Sample No. 1, was produced from an injection-molding formulation comprising: 98.5 wt. % unfilled black impact modified nylon 6 having an average specific gravity of 1.13 (ASTM
D792), an average notched izod rating of 1.5 ft-lb/in (ASTM D256), an average tensile yield strength of 10,500 psi (ASTM D638) and an average flexural modulus of 400,000 psi (ASTM D790) such as that commercially available from The Matrix Group, Evansville, Indiana, USA; and 1.5 wt. % IRGAGUARD~ B 1325. The formulation was injection-molded at a temperature of approximately 516 °F and 80% of the maximum injection pressure. The casters were then removed from the mold and cooled. A
comparative sample, Sample No. 2 was produced using the same process, except that the formulation did not include an antimicrobial additive (100 wt. % unfilled black impact modified nylon 6).
The physical properties of the two samples were measured and the results are provided in Table 3. The impact test was performed by dropping a weight of 30 lbs.
from a height of 5" on the caster wheels and noting whether mechanical failure occurs.
Atty/Docket Nc~. 921184-913100 _g_ Table 3 Sample No. Durability Test Impact Test ANSI/BIFMA (I50 in-Ib.) Draft A ril 2002 1 (inventive) Hard wheels Hard wheels > 100,000 cycles Passed 2 (comparative) Hard wheels Hard wheels > 100,000 cycles Passed Again, it is surprisingly shown that the addition of antimicrobial agent to the injection-molding formulation does not degrade the physical properties of the resultant product.
While the invention has been described in detail for the purpose of illustration, it is understood that such detail is solely for that purpose, and variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the following claims.
Claims (17)
1. An injection-molded plastic article having reduced susceptivity to microbial growth thereon, said injection-molded article made from a molding formulation comprising:
a thermoplastic resin selected from the group consisting of polyamide thermoplastic resins, polyethylene thermoplastic resins, polyurethane thermoplastic resins, polypropylene thermoplastic resins, polyvinyl chloride thermoplastic resins and blends of the foregoing; and an antimicrobial additive.
a thermoplastic resin selected from the group consisting of polyamide thermoplastic resins, polyethylene thermoplastic resins, polyurethane thermoplastic resins, polypropylene thermoplastic resins, polyvinyl chloride thermoplastic resins and blends of the foregoing; and an antimicrobial additive.
2. The injection-molded article of claim 1, wherein the thermoplastic resin comprises a polyamide thermoplastic resin.
3. The injection-molded article of claim 2, wherein the polyamide thermoplastic resin comprises nylon 6.
4. The injection-molded article of claim 1, wherein the antimicrobial additive comprises 5-chloro-2-(2,4 dichlorophenoxy) phenol.
5. The injection-molded article of claim 4, wherein the antimicrobial additive is present from about 0.1 wt. % to about 1.25 wt. % based on the total weight of the article.
6. The injection-molded article of claim 1, wherein the formulation further includes high modulus fiber.
7. The injection-molded article of claim 1, wherein the formulation further includes carbon black.
8. The injection-molded article of claim 1, wherein the article comprises a chair base.
9. The injection-molded article of claim 1, wherein the article comprises a caster.
10. The injection-molded article of claim 1, wherein said thermoplastic resin is nylon 6 and said molding formulation further includes high modulus fibers;
said antimicrobial additive comprises 5-chloro-2-(2,4 dichlorophenoxy) phenol; and wherein said antimicrobial additive comprises about 0.1 wt. % to about 1.25 wt. % of the molding formulation based on the total weight of the molding formulation.
said antimicrobial additive comprises 5-chloro-2-(2,4 dichlorophenoxy) phenol; and wherein said antimicrobial additive comprises about 0.1 wt. % to about 1.25 wt. % of the molding formulation based on the total weight of the molding formulation.
11. A method of forming an article having antimicrobial properties, said method comprising:
providing a molding formulation comprising (i) a thermoplastic resin selected form the group consisting of nylon resin, polyvinylidene fluoride polymer resin, polyethylene resin and blends of the foregoing and (ii) an antimicrobial additive formulation comprising an antimicrobial additive dispersed in a carrier resin, said carrier resin being compatible with said thermoplastic resin and said antimicrobial additive comprising 5-chloro-2-(2,4 dichlorophenoxy) phenol;
heating said molding formulation to create a plastified resin formulation;
and injecting the plastified formulation into a mold to form said article.
providing a molding formulation comprising (i) a thermoplastic resin selected form the group consisting of nylon resin, polyvinylidene fluoride polymer resin, polyethylene resin and blends of the foregoing and (ii) an antimicrobial additive formulation comprising an antimicrobial additive dispersed in a carrier resin, said carrier resin being compatible with said thermoplastic resin and said antimicrobial additive comprising 5-chloro-2-(2,4 dichlorophenoxy) phenol;
heating said molding formulation to create a plastified resin formulation;
and injecting the plastified formulation into a mold to form said article.
12. The method of claim 11, wherein said thermoplastic resin is nylon 6.
13. The method of claim 11, wherein said said carrier resin comprises polyethylene terephthalate.
14. The method of claim 11, wherein said antimicrobial additive formulation comprises about 25 wt. % 5-chloro-2-(2,4 dichlorophenoxy) phenol and about 75%
polyethylene terephthalate.
polyethylene terephthalate.
15. The method of claim 11, wherein said antimicrobial formulation comprises about 0.5 to about 5 wt. % of the molding formulation.
16. The method of claim 11, wherein said molding formulation further includes high modulus fibers.
17. The method of claim 11, wherein said thermoplastic resin is nylon 6, said molding formulation further includes high modulus fibers, and said antimicrobial formulation comprises about 25 wt. % 5-chloro-2-(2,4 dichlorophenoxy) phenol and about 75% polyethylene terephthalate, wherein said antimicrobial formulation comprises about 0.5 to about 5 wt. % of the molding formulation.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US26644702A | 2002-10-08 | 2002-10-08 | |
| US10/266,447 | 2002-10-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2444711A1 true CA2444711A1 (en) | 2004-04-08 |
Family
ID=32392343
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2444711 Abandoned CA2444711A1 (en) | 2002-10-08 | 2003-10-08 | Antimicrobial injection-molded components and method for producing the same |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN1508185A (en) |
| CA (1) | CA2444711A1 (en) |
| MX (1) | MXPA03009162A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2505784A (en) * | 2012-09-26 | 2014-03-12 | Titan Furniture Uk Ltd | An antimicrobial chair |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103382273A (en) * | 2012-05-03 | 2013-11-06 | 辽宁辽杰科技有限公司 | Far-infrared antibacterial thermoplastic composite sheet material and its preparation method and use |
-
2003
- 2003-10-08 CN CNA2003101181010A patent/CN1508185A/en active Pending
- 2003-10-08 CA CA 2444711 patent/CA2444711A1/en not_active Abandoned
- 2003-10-08 MX MXPA03009162 patent/MXPA03009162A/en not_active Application Discontinuation
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2505784A (en) * | 2012-09-26 | 2014-03-12 | Titan Furniture Uk Ltd | An antimicrobial chair |
| WO2014049315A1 (en) * | 2012-09-26 | 2014-04-03 | Titan Furniture (Uk) Limited | Furniture |
| GB2505784B (en) * | 2012-09-26 | 2014-09-17 | Titan Furniture Uk Ltd | Furniture |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1508185A (en) | 2004-06-30 |
| MXPA03009162A (en) | 2004-09-10 |
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