KR20130132961A - Noise damping compositions - Google Patents

Abstract

A thermoplastic composition having excellent vibration damping and noise suppression properties, which can be manufactured at low cost, and molded articles made therefrom are disclosed. The noise damping composition of the present invention comprises: (a) about 50-85 weight percent polyamide; (b) about 5 to 45 weight percent fibrous reinforcement; (c) about 1 to 25 weight percent zinc oxide; And (d) about 0-15% by weight of other additives; Here, the weight percentages are based on the total weight of the noise damping composition, provided the composition is essentially free of flame retardants.

Description

Noise damping composition {NOISE DAMPING COMPOSITIONS}

This application claims the benefit of Chinese Patent Application No. 201010624765.4, filed December 27, 2010, which is incorporated herein by reference.

The present invention relates to thermoplastic compositions having improved vibration damping and noise reduction properties. The present invention is particularly useful as a component in the attenuation of noise generated in a drive system in a transport vehicle. The invention also relates to noise-damping articles molded from such compositions.

When high specific stiffness, strength and controlled expansion were required, the fiber reinforced composites were good lightweight substitutes for the metal. These composites have been particularly effective for applications in commercial transport systems. The tailorability of the composite provides an effective means for optimizing the design of components that must be lightweight and meet stressed thermal and mechanical system requirements, but these structures nevertheless provide undesirable levels of vibration. And experience noise. For example, vehicle engine noise delivered to a vehicle's cabin contributes to occupant discomfort.

Normal human ears can hear sounds with frequencies between 20 Hz and 20,000 Hz. Nevertheless, the ear's response to sound is very dependent on the frequency content of the sound. The human ear has a peak response around 2,500-3,000 Hz and a relatively low response at low frequencies. The audible sound pressure range for the human ear is 0 dB to 120 dB. The noise that people hear in the cabin of an automobile originates essentially from: (a) a drive system comprising an engine, a transmission system, and accessories; (b) road excitation, and (c) aerodynamic excitation. On the other hand, the subjective rating of the noise inside the vehicle is as follows: if the noise level does not exceed 67 dB, it is considered "quiet", 73 dB is considered "clear" and 79 dB is considered "due". DB is a logarithmic scale of sound pressure level, so a 1 dB reduction in noise level means 1/10 of the sound pressure level. To reduce the noise level inside the cabin, the interior must be well isolated from road and wind noise and drive noise levels must be suppressed.

Typically the vibration frequency generated by the drive system is in the low frequency range, typically around 500 Hz to 3,000 Hz. In an effort to reduce drive noise levels, various techniques have been employed including the use of polymer coatings on engine parts, sound absorption barriers, and laminated panels with viscoelastic layers. Other noise reduction efforts have included the use of noise reduction engine mount designs, including active engine mounts employing magneto-rheological fluid actuators.

The use of laminated panels with viscoelastic layers has resulted in moderate damping of vibration and noise of values generally below 5%. Another disadvantage of this approach lies in the considerable weight added to the basic structure (probably 20-30%).

Thermoplastics having good sound damping properties by blending with viscoelastic elastomers generally have insufficient rigidity, modulus strength, or high temperature tolerability to be useful in many applications such as oil pans and the like.

US Pat. No. 6,849,684 (Poppe et al) discloses blends of fibrous fillers, ie, rigid polyester resins and soft thermoplastic copolyether ester elastomers reinforced with carbon fibers.

In summary, although existing noise reduction efforts may have a positive effect in reducing the transmission of noise to the cabin, there remains a need for thermoplastic compositions that have good vibration damping and noise suppression properties and are inexpensive to manufacture. .

The present invention

(a) about 50 to 85 weight percent polyamide;

(b) about 5 to 45 weight percent fibrous reinforcement;

(c) about 1 to 25 weight percent zinc oxide; And

(d) providing a noise damping composition comprising a mixture of about 0 to 15 weight percent of other additives;

Where the weight percents are based on the total weight of the noise damping composition,

However, the composition is essentially free of flame retardants.

In one embodiment of the noise damping composition of the present invention, the polyamide is nylon 66, nylon 6, nylon 66/6, nylon 46, nylon 1010, nylon 10, nylon 12, nylon 1212, nylon 610, nylon 612, nylon 66 /. 6T, nylon 6T / DT, nylon MXD-6, and blends thereof.

In one embodiment of the noise damping composition of the present invention, the polyamide is nylon 66, nylon 6, nylon 66/6, or a blend thereof; The amount of polyamide ranges from about 50 to 75 weight percent based on the total weight of the noise damping composition.

In one embodiment of the noise damping composition of the present invention, the fibrous reinforcing agent is glass fiber , carbon fiber, or para-aramid fiber.

In one embodiment of the noise damping composition of the present invention, the fibrous reinforcing agent is glass fiber and the amount of the fibrous reinforcing agent is in the range of about 20 to 40% by weight based on the total weight of the sound dampening composition.

In one embodiment of the noise damping composition of the present invention, the weight ratio between the polyamide and the fibrous reinforcement is in the range of about 50:50 to 95: 5.

In one embodiment of the noise damping composition of the present invention, the zinc oxide is nano-zinc oxide or zinc oxide whisker and the amount of zinc oxide is in the range of about 5 to 10% by weight based on the total weight of the noise damping composition. .

In one embodiment of the noise damping composition of the present invention, the zinc oxide is nano-zinc oxide having a particle size in the range of about 5 to 100 nm, preferably about 10 to 60 nm.

In one embodiment of the noise damping composition of the present invention, the zinc oxide is a zinc oxide whisker with a size in the micrometer range.

In one embodiment of the noise damping composition of the present invention, the zinc oxide is a tetrapod-shaped zinc oxide whisker that has not been surface treated with a silane coupling agent.

 In one embodiment of the noise damping composition of the present invention, the amount of zinc oxide ranges from about 5 to 10 weight percent based on the total weight of the noise damping composition.

In one embodiment of the noise damping composition of the present invention, the other additives include antioxidants, heat stabilizers, ultraviolet stabilizers, colorants including dyes and pigments, lubricants, hydrolysis resistant, demolding agents. , Minerals, mica, flow modifiers, and chain extenders.

The invention also provides a molded article comprising or made from the noise damping composition of the invention.

In one embodiment, the molded article of the present invention is a noise-damping part of a transportation vehicle, wherein the transportation vehicle is a motor vehicle, an aircraft, or a boat. In one embodiment, the molded article of the present invention comprises a component used in a transmission system, such as a bearing carrier, a transmission cover assembly, and a transmission housing; Components used in intake and exhaust devices such as air ducts, housings of air cleaners, air intake manifolds, exhaust manifolds, exhaust mufflers, EGR housings, exhaust pipes, and housings of three-way catalytic converters; Components used in cooling systems, such as shields, reservoir caps, radiator end tanks, intermediate cooler tanks, charge air coolers, and thermostat housings; Such as engine covers, engine mounts, oil reservoir tanks, oil pans, oil buffers, oil strainers, cylinder head covers, timing belt covers, hinged clips, binding bands, and electric motor brackets or housings. Components used in engine systems; Electronic fuel injection systems such as gasoline tanks, gasoline sub-tanks, oil reservoir tanks, fuel delivery modules, fuel delivery pipes, oil strainers, canisters, junction blocks, resonators, relay blocks, connectors, corrugations, and protectors Parts used for; It is selected from the group consisting of components used for the body, such as the engine front cover and the rear cover.

In another embodiment, the molded article of the present invention is a noise-damping component selected from the group consisting of power tools, electric motors, and household appliances including washing machines, air conditioners, fans, microwaves, refrigerators, and freezers.

The present invention further provides the use of the molded article of the present invention as a noise-damping part in a transport vehicle.

The noise damping composition of the present invention has excellent vibration damping and noise suppression properties and can be manufactured inexpensively. In addition, the compositions of the present invention still have high mechanical strength and high temperature tolerability, making them suitable for applications with working temperatures in excess of 150 ° C. Noise-damping articles molded from the compositions of the present invention are particularly useful as components in the attenuation of noise that occurs in drive systems in transportation vehicles.

Various other features, aspects, and advantages of the present invention will become more apparent with reference to the following detailed description, examples, and appended claims.

DETAILED DESCRIPTION OF THE INVENTION [

All publications, patent applications, patents, and other references mentioned herein are, unless otherwise indicated, explicitly incorporated herein by reference in their entirety as if fully set forth.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

Unless otherwise stated, all percentages, parts, and percentages are by weight.

As used herein, the term "made from" is synonymous with "comprising. &Quot; As used herein, the terms "including," "including," "including," "including," "having," "having," "containing," or "containing" Any other variation is intended to cover non-exclusive inclusions. For example, a composition, process, method, article, or apparatus that comprises a series of elements is not necessarily limited to such element, but may be embodied in other specific forms, Element.

Connector "configured" excludes any element, step, or component that is not explicitly stated. Within the scope of the claims, such phrases would normally close the claims to include materials other than those listed, except for the associated impurities. Where the phrase “consisting of” appears in the text section of the claims rather than immediately after the preamble, only the elements indicated in that section are limited; Other elements are not excluded from the claim as a whole.

The term " consisting essentially of " is used to define a composition, method, or apparatus that comprises a material, a step, a feature, an element, or an element in addition to what is literally discussed, , Step features, components, or elements do not materially affect the basic and novel feature (s) of the claimed invention. The term “consisting essentially of” occupies an intermediate position between “comprising” and “consisting of”.

The connector “essentially free” or “essentially free” component means that the composition of the present invention contains less than 1% by weight, preferably 0% by weight, based on the total weight of the noise damping composition. It means you should.

The term "comprising " is intended to encompass embodiments encompassed by the terms" consisting essentially of "and" consisting ". Likewise, the term "consisting essentially of " is intended to encompass embodiments encompassed by the term" consisting ".

And any value or parameter is given as a range, a preferred range, or a list of lower preferred values and lower preferred values, it is understood that any upper range or preferred value and any Quot; is understood to specifically disclose all ranges formed from any pair of lower limit ranges or desirable values. For example, if a range of "1 to 5" is listed, the listed ranges are "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 To 3 and 5 ", and the like. Where a range of numerical values is mentioned in this specification, unless stated otherwise, the range is intended to include all its integers and fractions within its range and range.

Where the term "about" is used to describe the endpoint of a value or range, the description should be understood to include the particular value or endpoint mentioned.

Further, unless expressly stated to the contrary, "or" is " referring to an exclusive or " For example, the condition A or B is satisfied by either: A is true (or exists), B is false (or not present), A is false (or nonexistent) Is true (or present), A and B are both true (or present).

In addition, the indefinite articles ("a" and "an") preceding the elements or components of the invention are intended to be non- limiting in terms of the number of elements or components (ie, occurrences). Thus, the indefinite article "a" or "an" should be understood to include one or at least one, and the singular form of the element or component also includes the plural unless the number is obviously meant to be singular.

In the description and / or claims of the present invention, the term “monopolymer” refers to a polymer derived from the polymerization of monomers of one species; "Copolymer" refers to a polymer derived from the polymerization of two or more species of monomers. Such copolymers include binary copolymers, terpolymers, or higher order copolymers.

In describing a given polymer, it is sometimes understood that the applicant refers to a polymer by the amount of monomers used to make the polymer or the monomers used to make the polymer. Although this description may not include certain terms used to describe the final polymer or may not include product-by-process terms, any such reference to monomers and amounts is intended to encompass the use of the polymer Should be construed to mean including monomers (i.e., copolymerized units of the monomers) or monomers thereof, and corresponding polymers and compositions thereof.

In the present invention, the term “flame retardant” generally refers to a known flame retardant, which is tetrabromo-bisphenol A (TBBA), tetrabromophthalic anhydride (TBPA), tetrabromobisphenol A bis (dibromopropyl ether) (BDDP), hexabromocyclododecane (HBCD), decabromodiphenyl ether (DBDE), 1,2-bis (pentabromophenyl) ethane (DBPE), tris (2,3-dibromopropyl) eye Halogen-containing flame retardants consisting of sociaurate (TBC), dodecachloropentacyclooctadecadiene, and chlorinated paraffins; Inorganic flame retardants composed of magnesium hydroxide, aluminum hydroxide, antimony oxide, and zinc borate; Resorcinol Bis (Diphenyl Phosphate) (RDP), Bisphenol-A Bis (Diphenyl Phosphate) (BDP), Resorcinol Bis (2,6-Dixylenyl Phosphate) (RDX), Diphenyl Isopropyl Phenyl phosphate (IPPP), triphenyl phosphate (TPP), dimethyl methylphosphonate (DMMP), tris (2-chloro-1-methyl-ethyl) phosphate (TCPP), tris (2-chloro-1- (chloro Phosphorus-containing flame retardants consisting of methyl) ethyl) phosphate (TDCPP), red, ammonium polyphosphate (APP), and melamine polyphosphate (MPP); And other flame retardants composed of melamine (MA) and melamine cyanurate (MC).

Embodiments of the present invention as described in the problem to be solved include any other embodiment described herein, and may be combined in any manner, and descriptions of the parameters within the embodiments may be derived from the noise damping compositions of the present invention and the Applied to the molded article produced.

The materials, methods, and examples of the present invention are illustrative only and are not intended to be limiting, except as specifically described. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described herein.

Hereinafter, the present invention will be described in detail.

(a) polyamide

Molded articles made from thermoplastic resins, such as polyamides, are frequently used as automotive under-hood parts due to their high heat resistance (eg nylon-66) and / or high toughness (eg nylon-6). Has been used.

Polyamide serves as the base resin for the present noise damping composition. Any polyamide made from lactam or amino acid known to those skilled in the art can be used.

Polyamides derived from a single reactant such as lactams, amino carboxylates, copolymers of these components, referred to as AB type polyamides, are described in Nylon Plastics (edited by Melvin L. Kohan, 1973, John Wiley and Sons, Inc.). .)] And may include aliphatic polyamides such as nylon 6, nylon 11 (poly-ω-undecanoamide), nylon 12 (poly-ω-dodecanoamide), and mixtures or copolymers thereof. have. Other types of known polyamides, called AABB type polyamides, prepared from the condensation of diamines with diacids, include nylon 66, nylon 610 (polyhexamethylene sebaamide), nylon 612 (polyhexamethylene dodecaneamide), Aliphatic polyamides such as nylon 46 (polytetramethylene adipamide), and nylon 1212 (polydodecamethylene dodecanamide). Nylon MXD-6 (poly (m-xylene adipamide)), polyhexamethylene terephthalamide (nylon 6T), poly (2-methylpentamethylene terephthalamide) (nylon DT), poly (2-methylpentamethylene) Other non-aliphatic polyamides may be suitable, including terephthalamide (nylon MST), polyhexamethylene isophthalamide (nylon 6I), or poly (2-methylpentamethylene) -isophthalamide (nylon M5I). have.

Examples of polyamide copolymers are nylon 66/6, nylon 66/610, nylon 66 / 6T, nylon 66 / 6I, nylon 6T / DT, nylon 6T / 6I / 66, nylon 6T / 6I / 610, nylon 6T / 6I , And nylon 6T / MST.

Since polyamides and processes therefor are well known to those skilled in the art, their disclosure is omitted here for brevity.

In one embodiment, polyamides suitable for use in the present invention are nylon 66, nylon 6, nylon 66/6, nylon 46, nylon 1010, nylon 10, nylon 12, nylon 1212, nylon 610, nylon 612, nylon 66 / 6T, nylon 6T / DT, nylon MXD-6, and blends thereof.

In a preferred embodiment, the polyamide of the present invention is nylon 66, nylon 6, nylon 6/66, or blends thereof.

Polyamides based on blends of nylon 66 and nylon 6 may be useful if the presence of nylon 6 is less than 40% by weight.

Among the polyamide resins mentioned above, those having a number average molecular weight of about 7,000 to 30,000 are preferably used in the present invention.

The amount of polyamide employed in the noise damping composition of the present invention is about 50 to 85% by weight, preferably about 50 to 75% by weight, more preferably about 55 to 70% by weight, based on the total weight of the noise damping composition. Range.

(b) fiber Reinforcing agent

In order to improve mechanical strength, such as tensile strength, flexural strength, and to suppress shrinkage of the molded article, a fibrous reinforcement is added to the noise damping composition used in the present invention.

Examples of fibrous reinforcements include inorganic fibers such as glass fibers , carbon fibers , graphite fibers, silica-alumina fibers , zirconia fibers, ceramic fibers, stainless steel, metal fibers such as aluminum, titanium, copper, or bronze fibers and para- Organic fibers such as aramid fibers, meta-aramid fibers, fluororesin fibers , or liquid crystalline aromatic fibers. One or two or more of these may be used, or a combination thereof may be used. In terms of reinforcing effect, preferably, the fibrous reinforcing agent is glass fiber, carbon fiber, or para-aramid fiber, for example Kevlar® fiber available from DuPont Co., USA. . In view of availability and price, glass fibers are more preferred.

In one embodiment of the noise damping composition of the present invention, the fibrous reinforcing agent is glass fiber, carbon fiber, or para-aramid fiber. In another embodiment of the noise damping composition of the present invention, the fibrous reinforcing agent is glass fiber.

As glass fiber, the glass fiber normally used for a thermoplastic resin can be used. Among these glass fibers, chopped strands made from E-glass (alkali glass) are preferred. The average fiber diameter of the fibrous reinforcing agent is not specifically limited, and is, for example, within the range of 1 to 100 μm, preferably about 3 to 30 μm, more preferably about 5 to 15 μm. The average fiber length of the fibrous reinforcement is also not particularly limited and is, for example, within the range of about 2 to 4 mm.

Examples of suitable glass fibers include NEG275H, manufactured by Nippon Electric Glass Co., Ltd., and ChopVantage® available from PPG Industries Fiber Glass. It includes. Additionally, if necessary, fibrous reinforcing agents may be employed through the use of surface-treating agents (e.g., functional compounds comprising epoxy compounds, acrylic compounds, isocyanate compounds, silane compounds, or titanate compounds). Surface-treatment. Fibrous reinforcing agents may be pre-surface-treated with the surface-treatment agent or surface-treated by the addition of the surface-treatment agent during the preparation of the material. In order to enhance the adhesion to the polyamide resin, the glass fibers are preferably surface-treated with a silane-based compound (also known as a silane coupling agent).

The fibrous reinforcing agent can be blended into the polyamide resin at any stage from the preparation (polycondensation) of the polyamide resin to its molding. Preferably, the fibrous reinforcement is introduced into the extruder during molding of the polyamide resin and melt-kneaded with the polyamide resin therein.

The amount of fibrous reinforcement employed in the noise damping composition of the present invention is from about 5 to 45% by weight, preferably from about 20 to 40% by weight, more preferably from about 25 to 35% by weight, based on the total weight of the noise damping composition. Range.

In the noise damping composition of the present invention, the weight ratio between the polyamide and the fibrous reinforcement is about 50:50 to 95: 5; Preferably, about 55:45 to 85:15; More preferably, about 60:40 to 80:20; Most preferably in the range of about 65:35 to 75:25. If the amount of fibrous reinforcing agent is higher than the amount of polyamide (by weight), the resulting composition tends to have low fluidity.

(c) zinc oxide

Zinc oxide (ZnO) is a white crystalline material used in many different applications. Technically important, it is a unique combination of properties of ZnO, that is, it is a transparent, UV absorbing, luminescent, piezoelectric, semiconducting, abrasion resistant, microwave absorbing, antimicrobial, nontoxic, and inexpensive material. Make. It is currently used in cosmetic sunscreens, varistors, white pigments in plastics and inks, semiconductor related applications. Pearlton et al, "Recent progress in processing and properties of ZnO", Prog. Mater. Sci., Vol. 50, pp 293-340 (2005).

Applicants have found that adding ZnO to a polyamide matrix in the presence of a fibrous reinforcement provides a composition with improved vibration damping and noise reduction properties. Therefore, zinc oxide plays an important role as a noise attenuator in the noise damping composition of the present invention. While not wishing to be bound by theory, it has been hypothesized that the damping effect of zinc oxide may be due to its piezoelectric properties.

Preferably, the zinc oxide is acicular, dendritic, or crystalline zinc oxide in wire form. In a more preferred embodiment, the zinc oxide is nano-zinc oxide (N-ZnO) or zinc oxide whisker, for example tetrapod-shaped zinc oxide whisker (T-ZnOw).

Nano-zinc oxide or zinc oxide nanoparticles are known to improve the thermal stability of polyacrylates and polyethylenes. Cho et al, "Effects of ZnO Nano Particles on Thermal Stabilization of Polymers", Polym. Eng. Sci., Vol 44, pp 1702-1706 (2004). In order to maximize the benefits that nano-ZnO can bring to the polymer, full dispersion of the nanoparticles in the polymeric matrix must be achieved.

“Nanoparticles” are understood by those skilled in the art to be particles having an average particle size of 5 to 100 nm through suitable manufacturing processes.

Zinc oxide whiskers, such as T-ZnOw, have a tetrapod shape in micro-images, and a porous shape in bulk. Under the microscope, zinc oxide crystals have four needle crystals extending from the central body. The length of each needle (or whisker) is greater than 3 micrometers as measured from its base in contact with the central body to the tip. Whiskers of T-ZnOw are known to be flexible and to have high elastic modulus and very high specific gravity of about 5.8. T-ZnOw, due to its unique shape, has good additional properties compared to other crystalline zinc oxides, for example high strength and high elasticity.

Similar to the fibrous reinforcing agent, zinc oxide can be surface-treated through the use of such surface-treating agents as needed. Zinc oxide can be pre-treated with the surface-treatment agent or surface-treated by the addition of the surface-treatment agent during the preparation of the material. In order to provide good dispersion of the nanoparticles in the polymeric matrix, the nano-zinc oxide is preferably surface-treated with a silane-based compound (also known as a silane coupling agent). Zinc oxide whiskers have less particle agglomeration and are preferably not surface-treated with a silane coupling agent.

In one embodiment of the noise damping composition of the present invention, the zinc oxide is nano-zinc oxide or zinc oxide whisker.

In another embodiment of the noise damping composition of the present invention, the zinc oxide is nano-zinc oxide having a particle size in the range of about 5 to 100 nm, preferably 10 to 60 nm.

In a further embodiment of the noise damping composition of the present invention, the zinc oxide is a zinc oxide whisker with a size in the micrometer range.

In one embodiment of the noise damping composition of the present invention, the zinc oxide is a tetrapod-shaped zinc oxide whisker that has not been surface treated with a silane coupling agent.

The amount of zinc oxide employed in the noise damping composition of the present invention is in the range of about 1 to 25% by weight, preferably about 5 to 10% by weight, based on the total weight of the noise damping composition.

(d) Other additives

The noise damping composition of the present invention may further comprise small amounts of any additives well known and commonly used in polymer technology. Examples of additives include, without limitation, antioxidants, heat stabilizers, ultraviolet stabilizers, colorants including dyes and pigments, lubricants, hydrolysis inhibitors, demolders, minerals, mica, flow modifiers, and chain extenders. These additive (s) are generally from about 0.01 to about 15% by weight, preferably from about 0.01 to about 10% by weight, so long as they do not degrade the basic and novel properties of the composition and do not significantly affect the performance of the composition. It may be present in the composition in phosphorous amounts.

As noted above, the noise damping compositions of the present invention are suitable for injection-molding, co-injection molding, compression molding, overmolding, profile extrusion, blow-molding, vacuum molding, and shape molding ( It can be formed into a desired shape by an optimal molding method such as form molding. For example, the noise damping compositions of the present invention may be used in molded articles used in automotive parts and other transportation vehicle parts.

Specific examples of applications of the noise damping compositions of the present invention may include parts or products related to automobiles and other transportation vehicles such as aircraft and boats. More specifically, automotive molded parts include components used in transmission systems such as bearing carriers, transmission cover assemblies, and transmission housings; Components used in intake and exhaust devices such as air ducts, housings of air cleaners, air intake manifolds, exhaust manifolds, exhaust mufflers, EGR housings, exhaust pipes, and housings of three-way catalytic converters; Components used in cooling systems, such as shields, reservoir caps, radiator end tanks, intermediate cooler tanks, charge air coolers, and thermostat housings; Components used in engine systems such as engine covers, engine mounts, oil reservoir tanks, oil pans, oil buffers, oil strainers, cylinder head covers, timing belt covers, hinge clips, binding bands, and electric motor brackets or housings; Electronic fuel injection systems such as gasoline tanks, gasoline sub-tanks, oil reservoir tanks, fuel delivery modules, fuel delivery pipes, oil strainers, canisters, junction blocks, resonators, relay blocks, connectors, corrugations, and protectors Parts used for; Parts used in the body, such as the engine front cover and the rear cover.

The invention also relates to a steering knuckle, a control arm, a cast cradle, a cast instrument panel beam, or any structural casting or closed casting. It may be applicable to products such as closure casting. In addition, the present invention may be beneficial for traction drive motors for hybrid electric propulsion systems and pure electric propulsion systems, along with containment / housing for high voltage contactors.

Additionally, the noise damping composition of the present invention may include parts or products related to home appliances including power tools, electric motors, or washing machines, air conditioners, fans, microwaves, refrigerators, and freezers.

Other potential applications include any structure that produces unpleasant audible noise during operation, such as manufacturing machinery, railroad equipment, airliners, and the like. However, the present invention appears to be particularly suitable for molded parts that house or surround one or more rotating noise-generating components of transportation.

Example

The abbreviation "E" meaning "example" and "C" meaning "comparative example" are followed by a number indicating in which example the composition is prepared. The examples and comparative examples were all prepared and tested in a similar manner. Unless otherwise indicated, percentages are by weight.

material

PA1: Polyamide 66 resin manufactured by DuPont Company under the trade name Zytel® 101L NC010.

PA2: Polyamide 66 containing 35% by weight of reinforced glass fibers, manufactured by DuPont under the trade name Zytel® 70G35 BK267.

PA3: Polyamide containing 35% by weight of reinforced glass fibers made by DuPont under the trade name Zytel® 73G35 BK262 6.

N-ZnO: Abbreviation for nano-zinc oxide, average size of about 30 nm, surface modified with 2 wt% KH570, purchased from Veking, Hangzhou, China. KH570 is a silane coupling agent, 3-methacryloxypropyltrimethoxysilane (cas number 2530-85-0).

T-ZnOw: Abbreviation for tetrapod-shaped ZnO whiskers with needles or whiskers of at least 3 μm in length, typically 10 to 50 μm, purchased from Chengdu Crystrealm Co. Ltd.

GF: Glass fiber filaments of chopped glass fibers obtained from Nippon Electric Glass Company Limited under the trade name NEG 275H (the fibers are about 2.75-3.00 mm in length and about 10 μm in diameter).

Execution Example ( Working Example ) And Comparative Example  General Formulation Procedure

The polyamide was dried at 80 ° C. for 12 hours and the zinc oxide was dried at 120 ° C. for 12 hours. According to Tables 1 to 5 the component amounts of each example were fed to a twin screw extruder (Eurolab 16) to obtain the corresponding thermoplastic composition as pellets.

In the extruder of ten heat block configurations, the temperature of the extruder was set to be 270/275/275/275/275/275/275/275/280/280 ° C. The die temperature was 265-275 ° C. and the screw speed was 400-430 rpm. The polymer input speed was set at 2.45 kg / hour and the zinc oxide input was set at 0.05 kg / hour.

General forming procedure

Extruded pellets were dried to a moisture level of less than 40 ppm before molding. For mechanical properties testing, multipurpose test specimens according to ISO3167 were molded on a Sumitomo 100 ton molding machine with a screw diameter of 32 mm and a nozzle diameter of 5 mm. The barrel temperature was set to 280 ° C. and the molding temperature was 100 ° C. The multipurpose test specimen has a basic dumbbell shape with a central section of 150 mm in length and 10 mm wide by 4 mm thick by 80 mm long.

Test Methods

Attenuation Loss Coefficient (η): The attenuation loss factor is a measure of the sound attenuation characteristic indicating how much vibration related energy is absorbed by the material at a given temperature. The measurement was performed at 150 ° C. with a Dynamic Mechanical Analyzer (manufactured by Perkin Elmer) in accordance with ASTM E756-05. To demonstrate the effectiveness of the composition in noise attenuation, three data points were reported at representative frequencies in the range of 500 Hz to 4000 Hz for a given sample.

Transfer loss: reduction of the noise level resulting from passing the test sample (a disc shape with a diameter of 100 mm and a thickness of 2 mm) at frequencies in the range of 0 to 3200 Hz. The experimental setup included comparing the difference in noise distinguished by both microphones by using a speaker as the sound source in the acoustic chamber and putting two microphones in front of the test sample and the other in the rear. It was. The values were analyzed by the 1/3 octave band method and expressed in decibels to form a logarithmic scale. The greater the transmission loss, the more effective the material.

Tensile modulus was measured on an universal material tester Instron 5567 according to ISO527: 1993 (E).

Flexural modulus was tested on a universal material tester Instron 5567 according to ISO178: 2001 (E).

Heat deflection temperature (HDT) was determined at a load of 1.80 MPa according to ISO75.

Embodiments of the present invention are further defined in the following examples. The compositions of Examples and Comparative Examples are shown in Tables 1 to 5 together with the evaluation results.

From the results in Table 1, the following facts are clear.

When the amount of polyamide resin is maintained at 65%, the vibration damping effect tends to increase as the amount of zinc oxide increases. Since glass fibers (ie, fibrous reinforcing agents) served as reinforcing fillers for the noise damping composition of the present invention, as the amount of glass fibers decreased, the tensile modulus and flexural modulus also decreased. Therefore, depending on the specific application of the noise damping composition, select a suitable ratio between the fibrous reinforcement and the polyamide resin to meet the mechanical properties requirements; The noise damping composition of the present invention can then be obtained by varying the amount of zinc oxide to provide the desired damping effect. Preferably, for applications used in drive systems of transport vehicles, the ratio between the polyamide resin and the fibrous reinforcement in the present noise damping composition is 55:45 to 85:15; More preferably, 60:40 to 80:20; Most preferably, 65:35 to 75:25.

In one embodiment of the noise damping composition of the present invention, the weight ratio between the polyamide resin and the fiber reinforcement is 55:45 to 85:15; More preferably, 60:40 to 80:20; Most preferably, 65:35 to 75:25.

The heat deflection temperature (HDT) data of the running examples (E1 to E5) appeared to be higher or the same as that of the control sample (C1), indicating that applications with high temperature requirements, eg working temperatures of 150 ° C It is suggested that the noise damping composition of the present invention can be used in a drive system that is nearby.

From the results in Tables 2 to 3, the following facts are evident.

From the comparison between E6 to E10 vs C1 and E11 to E16 to C2, as judged by the attenuation loss coefficients (at 625 Hz, 1562 Hz, and 3124 Hz) that are greater than the attenuation loss coefficients of C1 or C2, respectively, 2 Compositions containing from 13% by weight of zinc oxide effectively provided vibration damping results. For E6 to E10 and E11 to E16, the ratio of polyamide resin to glass fiber was 65:35, and the resulting noise damping composition had a tensile strength of about 90 to 105% compared to that of each control sample (C1 or C2). Note that it still has elastic modulus and flexural modulus.

In addition, the noise damping compositions of the present invention (ie E7 to E9 vs C1) also demonstrated which can effectively reduce sound transmission by 2.5 dB.

In one embodiment, the noise damping composition of the present invention consists essentially of, comprises, or contains about 1 to 15 weight percent zinc oxide, wherein the zinc oxide is nanoparticles having an average particle size of less than 60 nm, Weight percent is based on the total weight of the noise damping composition.

From the results in Table 4, the following facts are obvious.

From the comparison between E17 to E21 versus C3 and E22 to C2, 2 to 9 weights, as determined by the attenuation loss factor (at 625 Hz, 1562 Hz, and 3124 Hz) that is greater than the attenuation loss factor of C3 or C2. Compositions containing% zinc oxide whiskers effectively provided vibration damping results.

Comparing the tensile modulus and flexural modulus data of the working examples (E17 to E21 and E22) with those of the respective control examples (C3 or C2), the presence of zinc oxide did not adversely affect the mechanical properties of the noise damping composition.

In addition, the noise damping compositions of the present invention (ie, E17 to E21 vs C3) also demonstrated which can effectively reduce sound transmission by 3.8 dB.

In one embodiment, the noise damping composition of the present invention consists essentially of, comprises, or contains about 1 to 10 weight percent zinc oxide, wherein zinc oxide is a tetrapod-shaped zinc oxide whisker, and the weight percent is Based on the total weight of the noise damping composition.

While the invention has been illustrated and described in typical embodiments, it is not intended to be limited to the details shown, as various modifications and substitutions are possible without departing from the spirit of the invention. Modifications and equivalents of the invention disclosed herein may thus be devised by those skilled in the art using routine experimentation and the like, and all such modifications and equivalents are intended to be within the spirit and scope of the present invention as defined by the following claims .

Claims (16)

(a) 50 to 85 weight percent polyamide;
(b) 5-45 weight percent fibrous reinforcement;
(c) 1 to 25 weight percent zinc oxide; And
(d) 0 to 15 weight percent of other additives;
Wherein the weight percent is based on the total weight of the noise damping composition, provided that the composition is essentially free of flame retardant. The method of claim 1 wherein the polyamide is nylon 66, nylon 6, nylon 66/6, nylon 46, nylon 1010, nylon 10, nylon 12, nylon 1212, nylon 610, nylon 612, nylon 66 / 6T, nylon 6T / DT , Noise reduction composition selected from the group consisting of nylon MXD-6, and blends thereof. The method of claim 2, wherein the polyamide is nylon 66, nylon 6, nylon 66/6, or a blend thereof; The noise damping composition wherein the amount of polyamide is in the range of 50 to 75 weight percent based on the total weight of the noise damping composition. The noise damping composition of claim 1, wherein the fibrous reinforcing agent is glass fiber, carbon fiber, or para-aramid fiber. The noise damping composition of claim 1, wherein the fibrous reinforcement is glass fiber and the amount of fibrous reinforcement is in the range of 20 to 40 weight percent based on the total weight of the noise damping composition. The noise damping composition of claim 1 wherein the weight ratio between the polyamide and the fibrous reinforcement is in the range of 50:50 to 95: 5. The noise damping composition of claim 1, wherein the zinc oxide is selected from nano-zinc oxide or zinc oxide whiskers and the amount of zinc oxide is in the range of 5 to 10 wt% based on the total weight of the noise damping composition. 8. The noise damping composition of claim 7, wherein the zinc oxide is nano-zinc oxide having a particle size in the range of 5 to 100 nm. 8. The noise damping composition of claim 7, wherein the zinc oxide is a zinc oxide whisker with a size in the micrometer range. 8. The noise damping composition of claim 7, wherein the zinc oxide is a tetrapod-shaped zinc oxide whisker that has not been surface treated with a silane coupling agent. The noise damping composition of claim 1, wherein the amount of zinc oxide ranges from about 5 to 10 weight percent based on the total weight of the noise damping composition. The method of claim 1, wherein the other additives are antioxidants, heat stabilizers, ultraviolet stabilizers, colorants including dyes and pigments, lubricants, hydrolysis resistant, demolding agents, minerals, mica, flows A noise damping composition selected from the group consisting of a modifier, and a chain extender. A molded article comprising the noise damping composition of claim 1. The molded article of claim 13, wherein the molded article is a noise-damping part of a transportation vehicle, wherein the transportation vehicle is an automobile, an aircraft, or a boat. Parts used in transmission systems, parts used in intake and exhaust systems, parts used in cooling systems, parts used in engine systems, parts used in electronic fuel injection systems, and in bodies The molded article of claim 13 or the noise-damping part of claim 14 selected from the group consisting of parts. The molded article of claim 13 selected from the group consisting of power tools, electric motors, and household appliances.