Low noise tire, tire inner polyurethane foam sound absorbing liner composition for manufacturing the tire, and tire inner polyurethane foam sound absorbing liner method using the composition

Abstract

The present invention relates to a low-noise tire, a tire inner polyurethane foam sound absorbing liner composition for manufacturing the low-noise tire, and a tire inner polyurethane foam sound absorbing liner method using the tire inner polyurethane foam sound absorbing liner composition, and more particularly, to a low-noise tire, a tire inner polyurethane foam sound absorbing liner composition for manufacturing the low-noise tire, and a tire inner polyurethane foam sound absorbing liner method using the tire inner polyurethane foam sound absorbing liner composition, in which, in order to reduce cavity resonance noise, which is generated due to vibration force generated between a tire tread and a road surface being transferred to a cavity space inside the tire and an axle, and then causing in-vehicle noise, a liquid foaming polyurethane composition is conveniently, rapidly, and accurately coated to an inner surface of the tire corresponding to the tire tread in a liquid foam spray manner, and is cured to form a polyurethane sound absorbing liner, whereby the low-noise tire exhibits improved low-noise performance.

Description

Technical Field

[0001] This invention relates to a low-noise tire, a polyurethane foam sound-absorbing lining composition for manufacturing the tire, and a method for forming a polyurethane foam sound-absorbing lining inside a tire using the composition. More specifically, this invention relates to a low-noise tire, a polyurethane foam sound-absorbing lining composition for manufacturing the tire, and a method for forming a polyurethane foam sound-absorbing lining inside a tire using the composition. In order to reduce cavity resonance noise generated when the excitation force generated between the tire tread and the road surface during driving is transmitted to the internal cavity of the tire and the axle and manifests as interior noise, a polyurethane foam sound-absorbing lining composition is simply, quickly, and precisely sprayed and foamed onto the inner surface of the tire corresponding to the tire tread, and then cured to form a polyurethane foam sound-absorbing lining, thereby improving the low-noise performance of the tire. Background Technology

[0002] In recent years, with the widespread adoption of electric vehicles, people have increasingly demanded reduced in-vehicle noise and noise caused by tire tread patterns. This is a way to improve vehicle quality by enhancing ride comfort and ensuring a more comfortable driving environment.

[0003] Among these noises, the low-frequency cavity resonance noise, ranging from 200 Hz to 250 Hz, is generated when the vibration force generated between the tire tread and the road surface during driving is transmitted to the internal cavity of the tire and the axle and manifests as noise inside the vehicle. It appears as a sound wave with sharp peaks inside the vehicle, causing discomfort to the driver and reducing ride comfort.

[0004] In particular, with the emergence of electric vehicles with very low or even no engine noise, and with tires being fitted with increasingly lower aspect ratios and larger rim diameters, tire cavity resonance noise has become an even more critical issue.

[0005] Regarding conventional techniques for reducing tire cavity resonance noise, Korean Patent No. 10-1439558 (registration date: September 2, 2014) discloses a tire noise reduction device formed by fixing soft polyurethane foam to an annular strip member, wherein the density of the soft polyurethane foam is 7 kg / m³. 3 Up to 40kg / m 3 Density per unit (kg / m³) 3 The tear strength is 0.39 N / cm to 0.70 N / cm. The noise reduction device is located on the inner surface of the tire and is detachably mounted on the tire.

[0006] Furthermore, Korean Patent No. 10-1993303 (registration date: June 20, 2019) discloses a pneumatic tire with a noise reduction component. This pneumatic tire includes a pneumatic tire 2, a carcass ply 6 (the carcass ply 2 is configured to form the tire 2 skeleton parallel to the inner liner 8 on the lower side of the tire tread 4 that contacts the road surface), a rim 20 (the rim 20 is mounted to the tire 2 via a bead portion 10, the bead portion 10 being folded upwards and wrapped by the carcass ply 6), and a noise reduction component 30 (the noise reduction component 30 is laminated onto the carcass). In the internal region between the ply 6 and the inner liner 8 (placed at the shoulder 16), the noise reduction member is arranged in an annular shape divided at predetermined intervals along the circumferential direction to reduce cavity resonance noise generated in the cavity 12 between the tire 2 and the rim 20. The shoulder 16 is formed on the left (L) and right (R) sides in the width direction relative to the centerline (CL) of the tire 2. The noise reduction member 30 is formed by laminating at least one selected from sound-insulating tape, sound-insulating rubber sheet and sound-insulating fiber adhesive, or by laminating a combination of such materials.

[0007] In addition, Korean Patent No. 10-2075314 (registration date: February 3, 2020) discloses a tire for reducing cavity resonance noise, wherein two to four block-shaped porous foam sound-absorbing components are attached to the inner surface of the tire at 90-degree angles along the circumferential direction, and these porous foam sound-absorbing components are made of porous melamine resin foam.

[0008] Here, the porous foam sound-absorbing component is in the shape of an octahedron, with a top horizontal length of 10mm to 40mm, a bottom horizontal length of 100mm to 180mm, a vertical length of 100mm to 180mm, a height at both ends of 10mm to 20mm, and a center height of 25mm to 75mm. This porous foam sound-absorbing component comprises six rectangular faces and two hexagonal faces, with any one of the six rectangular faces contacting and adhering to the inner surface of the tire. The longitudinal direction of the porous foam sound-absorbing component is aligned with the circumferential direction of the tire. The volume of the porous foam sound-absorbing component is 36 × 10⁻⁶. 4 mm 3 The porous foam sound-absorbing component is then attached to the inner surface of the tire using a thermoplastic polyacrylate adhesive.

[0009] Furthermore, Korean Patent No. 10-2127660 (registration date: June 23, 2020) discloses an inflatable tire comprising a tread portion 100, a sidewall portion 200, and a bead portion 300. The inflatable tire includes a sound-absorbing member 350 attached to the inner surface of the tread portion 100; and a sound-insulating membrane 400 fixedly supported by the sound-absorbing member 350 to, together with the sound-absorbing member 350, separate the interior of the inflatable tire in the cross-sectional direction. The sound-absorbing member 350 is formed as a pair of rings, each ring having a predetermined distance from the side surface of the tread portion 100, and is formed as a circle in the circumferential direction of the tread portion 100.

[0010] In addition, Korean Patent Application Publication No. 10-2021-0091400 (publication date: July 22, 2021) discloses an inflatable tire including a tread portion 100, a sidewall portion 200 and a bead portion 300, wherein an inner liner 400 is mounted on the inner surface of the inflatable tire, forming a space portion 500 between the tread portion 100 and the inner liner 400, and a filler 600 is located in the space portion 500.

[0011] Furthermore, Korean Patent No. 10-2460711 (registration date: October 25, 2022) discloses a foam tape for sound-absorbing tires. This foam tape includes a release film, a pressure-sensitive adhesive layer formed on the lower surface of the release film, a base film formed on the lower surface of the pressure-sensitive adhesive layer, an adhesive layer formed on the lower surface of the base film, and a porous sound-absorbing material layer formed on the lower surface of the adhesive layer. The pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive. The weight-average molecular weight of the pressure-sensitive adhesive in the pressure-sensitive adhesive layer is between 200,000 and 2,000,000, and the weight-average molecular weight of the adhesive in the adhesive layer is between 1,000 and 80,000. The acrylic pressure-sensitive adhesive comprises alkyl acrylates having 4 to 17 carbon atoms, and the sound-absorbing material layer comprises polyurethane foam.

[0012] However, the conventional technique described above involves cutting polyurethane foam, which is used as a sound-absorbing material, into the required size and then attaching it to the inner circumferential surface of the tire. In order to attach the polyurethane foam, a primer is applied to the inner circumferential surface of the tire, and then the operator manually attaches the polyurethane foam.

[0013] Specifically, the method includes: molding a polyurethane foam, applying a primer or adhesive to the inner surface of the tire to enhance the adhesion between the molded polyurethane foam and the inner surface of the tire, and attaching the molded polyurethane foam to the inner circumferential surface of the tire.

[0014] This method requires multiple production steps, resulting in long processing time, high production costs, and low production efficiency. Furthermore, improper application of polyurethane foam may lead to problems such as imbalance during tire rotation or separation of the polyurethane foam from the tire.

[0015] In addition, the polyurethane foam attached to the tire is elongated and narrow, with a width of about 10 cm, which makes it difficult to attach it to the inside of the tire by hand, thereby reducing productivity and increasing the possibility of defects due to improper attachment.

[0016] To address the aforementioned issues, a method has been developed to spray and foam liquid polyurethane foam to form a foam lining inside a tire.

[0017] However, since it is impossible to achieve a strong bond between rubber (the main component of tires) and polyurethane foam (an organic chemical material) using ordinary adhesives, a primer is applied to the inner surface of the tire, and then lining foaming is performed to form polyurethane foam as an inner liner. However, when the primer is not adequately applied to the interface between the inner surface of the tire and the polyurethane foam, or when the tire experiences rapid acceleration and deceleration, separation may occur between the tire and the polyurethane foam due to differences in inertial forces.

[0018] Furthermore, when a foam liner is formed inside a tire by spraying and foaming liquid polyurethane foam, if there is overlap or gap at the start and end points of the liner, it may fall off due to changes in the weight and distribution of the liner, and the low noise performance may deteriorate due to tire vibration.

[0019] In particular, electric vehicles have much higher torque than conventional diesel or gasoline vehicles, and their rapid acceleration and deceleration performance is superior, thus exacerbating the aforementioned problems. Summary of the Invention

[0020] Technical issues This invention was proposed in view of the problems encountered in the prior art. The purpose of this invention is to provide a low-noise tire, a polyurethane foam sound-absorbing liner composition for manufacturing the tire, and a method for forming a polyurethane foam sound-absorbing liner inside the tire using the composition. In order to reduce the cavity resonance noise generated when the excitation force generated between the tire tread and the road surface during driving is transmitted to the internal cavity of the tire and the axle and manifests as in-vehicle noise, the polyurethane foam sound-absorbing liner composition is simply, quickly and accurately sprayed and foamed onto the inner surface of the tire corresponding to the tire tread, and then cured to form a polyurethane foam sound-absorbing liner, thereby improving the low-noise performance of the tire.

[0021] Technical solution To achieve the above objectives, the present invention provides a polyurethane foam sound-absorbing liner composition for use inside tires. This composition reduces cavity resonance noise generated when the vibration force between the tire tread and the road surface during driving is transmitted to the tire's internal cavity and axle, manifesting as interior noise. The polyurethane foam sound-absorbing liner composition is simply, quickly, and precisely sprayed and foamed onto the inner surface of the tire corresponding to the tire tread, and then cured to form the polyurethane foam sound-absorbing liner. The composition comprises, based on 100 parts by weight, a polyol premixed composition, 50 to 60 parts by weight of a mixed MDI (methylene diphenyl diisocyanate) curing agent composition, wherein the polyol premixed composition comprises 3% to 40% by weight of polyol 1 (glycerol, OH value = 10 mg KOH / g to 30 mg KOH / g), 40% to 70% by weight of polyol 2 (glycerol, OH value = 31 mg KOH / g to 40 mg KOH / g), and 10% to 40% by weight of polyol 3 (glycerol, OH value = 10 mg KOH / g to 30 mg KOH / g). =41mgKOH / g to 50mgKOH / g), 5% to 30% by weight of polyol 4 (glycerol, OH value = 51mgKOH / g to 60mgKOH / g), 1% to 10% by weight of chain extender 1 (diethanolamine, OH value = 1500mgKOH / g to 2500mgKOH / g), 0.1% to 1% by weight of chain extender 2 (1,4-butanediol, OH value = 500mgKOH / g to 1500mgKOH / g), 0.1% to 5% by weight of The crosslinking agent, 1 wt% to 5 wt% of foaming agent (water), 0.1 wt% to 3 wt% of polyurethane curing reaction catalyst, 0.1 wt% to 1 wt% of foaming catalyst and 0.1 wt% to 3 wt% of foam stabilizer, the mixed MDI (methylene diphenyl diisocyanate) curing agent composition comprises 4 wt% to 70 wt% of monomeric MDI (MMDI), 4 wt% to 70 wt% of carbodiimide-containing MDI (CMDI) and 10 wt% to 80 wt% of polymeric MDI (PMDI).

[0022] The crosslinking agent can be triethanolamine (OH value = 1500 mg KOH / g to 2500 mg KOH / g).

[0023] The polyurethane curing catalyst can be a mixture containing 33% by weight of triethylenediamine and 66% by weight of dipropylene glycol.

[0024] The foaming catalyst can be diethyltoluene diamine (DETDA).

[0025] Foam stabilizers can be polyether-modified polysiloxanes.

[0026] Furthermore, the present invention provides a method for forming a polyurethane foam sound-absorbing lining inside a tire, the method comprising preparing a polyol premix composition comprising 3% to 40% by weight of polyol 1 (glycerol, OH value = 10 mg KOH / g to 30 mg KOH / g), 40% to 70% by weight of polyol 2 (glycerol, OH value = 31 mg KOH / g to 40 mg KOH / g), and 10% to 40% by weight of polyol 3 (glycerol, OH value = 41 mg KOH / g). 5% to 30% by weight of polyol 4 (glycerol, OH value = 51 mg KOH / g to 60 mg KOH / g), 1% to 10% by weight of chain extender 1 (diethanolamine, OH value = 1500 mg KOH / g to 2500 mg KOH / g), 0.1% to 1% by weight of chain extender 2 (1,4-butanediol, OH value = 500 mg KOH / g to 1500 mg KOH / g), 0.1% to 5% by weight of crosslinking agent, 1% by weight The mixture comprises 5% to 5% by weight of a foaming agent (water), 0.1% to 3% by weight of a polyurethane curing reaction catalyst, 0.1% to 1% by weight of a foaming catalyst, and 0.1% to 3% by weight of a foam stabilizer; and a mixed MDI (methylene diphenyl diisocyanate) curing agent composition comprising 4% to 70% by weight of monomeric MDI (MMDI), 5% to 70% by weight of carbodiimide-containing MDI (CMDI), and... 10% to 80% by weight of polymeric MDI (PMDI); preparation of a polyurethane foam sound-absorbing lining composition for use inside a tire, said composition being liquid and prepared by: introducing 50 to 60 parts by weight of a curing agent composition into a foaming mixing chamber based on 100 parts by weight of a polyol premixed composition, and then mixing; and forming a polyurethane foam sound-absorbing lining by spraying and foaming the liquid polyurethane foam sound-absorbing lining composition onto the inner surface of the tire corresponding to the tire tread, and then curing.

[0027] In this paper, a liquid polyurethane foam sound-absorbing lining composition can be sprayed and foamed onto the inner surface of the tire at a predetermined discharge rate for a predetermined time period using a foaming nozzle spaced at a predetermined distance from the inner surface of the tire. The predetermined time period corresponds to the time it takes to rotate once on the inner surface of the tire at a constant speed.

[0028] In addition, spraying and foaming the liquid polyurethane foam sound-absorbing liner composition onto the inner surface of the tire may include using a laser pointer to mark the start and end points for spraying and foaming on the inner surface of the tire, so that the polyurethane foam sound-absorbing liner does not overlap or create gaps at the start and end points.

[0029] The method may include forming holes in a cured film formed on the surface of a polyurethane foam sound-absorbing liner by punching holes with a needle brush or by marking design holes with a needle brush with design markings. The polyurethane foam sound-absorbing liner is formed by spraying and foaming a liquid polyurethane foam sound-absorbing liner composition onto the inner surface of a tire and then curing it.

[0030] Furthermore, the present invention provides a low-noise tire manufactured by the above method.

[0031] Beneficial effects This invention provides a low-noise tire, a polyurethane foam sound-absorbing liner composition for manufacturing the tire, and a method for forming a polyurethane foam sound-absorbing liner inside the tire using the composition. Specifically, to reduce cavity resonance noise caused by the transmission of vibration forces generated between the tire tread and the road surface during driving to the tire's internal cavities and axles, manifesting as interior noise, a liquid polyurethane foam sound-absorbing liner composition is simply, quickly, and precisely sprayed and foamed onto the inner surface of the tire corresponding to the tire tread, and then cured to form a polyurethane foam sound-absorbing liner, thereby improving the tire's low-noise performance. Attached Figure Description

[0032] Figure 1 The starting position of the process for forming the polyurethane foam sound-absorbing liner according to the present invention is shown; Figure 2 The rotational state of the process for forming the polyurethane foam sound-absorbing liner according to the present invention is shown; Figure 3 The final position of the process for forming the polyurethane foam sound-absorbing liner according to the present invention is shown; Figure 4 This is a cross-sectional view showing the interior of a low-noise tire according to the present invention. Detailed Implementation

[0033] The present invention will now be described in detail with reference to embodiments and / or accompanying drawings, enabling those skilled in the art to readily implement the invention. However, the invention can be embodied in various different forms and is not limited to the embodiments and / or drawings described herein.

[0034] One aspect of the present invention provides a polyurethane foam sound-absorbing liner composition for use inside a tire, wherein, in order to reduce cavity resonance noise generated when the excitation force generated between the tire tread and the road surface during driving is transmitted to the internal cavity of the tire and the axle and manifests as interior noise, a polyurethane foam sound-absorbing liner composition is simply, quickly, and precisely sprayed and foamed onto the inner surface of the tire corresponding to the tire tread, and then cured to form a polyurethane foam sound-absorbing liner; wherein the polyurethane foam sound-absorbing liner composition comprises, Based on 100 parts by weight of a polyol premixed composition, and 50 to 60 parts by weight of a mixed MDI (methylene diphenyl diisocyanate) curing agent composition, the polyol premixed composition comprises 3% to 40% by weight of polyol 1 (glycerol, OH value = 10 mg KOH / g to 30 mg KOH / g), 40% to 70% by weight of polyol 2 (glycerol, OH value = 31 mg KOH / g to 40 mg KOH / g), and 10% to 40% by weight of polyol 3 (glycerol, OH value = 4... 1 mg KOH / g to 50 mg KOH / g), 5 wt% to 30 wt% of polyol 4 (glycerol, OH value = 51 mg KOH / g to 60 mg KOH / g), 1 wt% to 10 wt% of chain extender 1 (diethanolamine, OH value = 1500 mg KOH / g to 2500 mg KOH / g), 0.1 wt% to 1 wt% of chain extender 2 (1,4-butanediol, OH value = 500 mg KOH / g to 1500 mg KOH / g), 0.1 wt% to 5 wt% of crosslinking agent... The mixed MDI (methylene diphenyl diisocyanate) curing agent composition comprises 4% to 70% monomeric MDI (MMDI), 4% to 70% carbodiimide-containing MDI (CMDI), and 10% to 80% polymeric MDI (PMDI). The composition also includes a binder, 1% to 5% by weight of a blowing agent (water), 0.1% to 3% by weight of a polyurethane curing reaction catalyst, 0.1% to 1% by weight of a foaming catalyst, and 0.1% to 3% by weight of a foam stabilizer.

[0035] In this paper, the polyurethane resin used in the polyurethane foam sound-absorbing lining composition is a flexible foam obtained by reacting a polyurethane foam composition containing a polyol, a polyisocyanate, a catalyst, a crosslinking agent, a foam stabilizer, and a blowing agent, wherein the polyol has a hydroxyl functional group (-OH) and the polyisocyanate has an isocyanate functional group (-NCO) in the molecule.

[0036] Polyols can be classified into monools, diols, triols, etc., based on the number of functional groups in the molecule. Isocyanates can also be classified into monoisocyanates, diisocyanates, etc., based on the number of functional groups in each molecule.

[0037] To prepare polymeric polyurethane resins, polyols with two or more functional groups and isocyanates are typically used. During the reaction, the components form urethane groups through reactions between the functional groups at the molecular ends. As shown in [Scheme 1] below, polymers with a large number of such urethane groups in the molecule are called polyurethanes.

[0038] [Option 1] R-NCO + R'-OH → [R-NH-COO-R'] Water reacts with isocyanate to form structurally unstable carbamic acid, which immediately decomposes into amine and carbon dioxide (CO2) ([Scheme 2]).

[0039] [Option 2] R-NCO + H2O → R-NH2 + CO2 The amine reacts again with the isocyanate to generate urea groups ([Scheme 3]), and the carbon dioxide gas produced by the decomposition forms tiny pores in the polyurethane resin, thus ultimately forming a porous structure dispersed in the polyurethane.

[0040] [Option 3] R-NH2+ R'-NCO → [R-NH-CO-NH-R'] Polyurethane foam is widely used as a material for automotive parts due to its excellent properties such as low density, high mechanical properties, and high heat resistance.

[0041] The polyurethane foam sound-absorbing lining composition used in this invention is a polyol premix composition, which comprises 3% to 40% by weight of polyol 1 (glycerol, OH value = 10 mg KOH / g to 30 mg KOH / g), 40% to 70% by weight of polyol 2 (glycerol, OH value = 31 mg KOH / g to 40 mg KOH / g), 10% to 40% by weight of polyol 3 (glycerol, OH value = 41 mg KOH / g to 50 mg KOH / g), and 5% to 30% by weight of polyol 4 (glycerol, OH value = 51 mg KOH / g). The product contains: 1% to 10% by weight of chain extender 1 (diethanolamine, OH value = 1500 mg KOH / g to 2500 mg KOH / g), 0.1% to 1% by weight of chain extender 2 (1,4-butanediol, OH value = 500 mg KOH / g to 1500 mg KOH / g), 0.1% to 5% by weight of crosslinking agent, 1% to 5% by weight of foaming agent (water), 0.1% to 3% by weight of polyurethane curing reaction catalyst, 0.1% to 1% by weight of foaming catalyst, and 0.1% to 3% by weight of foam stabilizer.

[0042] Therefore, polyols constitute at least 60% of the polyol premix composition, and a single polyol is not used alone; instead, different types of polyols are used depending on product characteristics and production conditions. Polyols are prepared by chemically bonding an initiator with PO (propylene oxide) and EO (ethylene oxide).

[0043] When using initiators such as glycerol (or glycerol), trimethylolpropane (TMP), triethanolamine (TEOA), 1,2,6-hexanetriol, phosphoric acid, or triisopropanolamine, triols with three hydroxyl groups (-OH) can be prepared (functionality = 3).

[0044] Therefore, the OH value depends on the PO / EO end-capping degree, which is related to the molecular weight of the chemically bonded polyol. Polyols with OH values ​​in the range of 20 to 60 mg KOH / g are used to manufacture polyurethane foam (which can be used as a material for automotive parts). Triol products account for the largest proportion in the mixed polyols and must be used at least 60% to meet the required properties such as flowability, molding performance, and hardness of the raw materials.

[0045] Furthermore, the vibration damping performance of polyurethane foam depends on the molecular weight of the polyol. In this invention, polyols with an OH value of less than 40 are mainly used, and several additional polyols (where the PO content and EO content are adjusted) are used at the same time to induce room temperature curing and prevent foam shrinkage.

[0046] According to a preferred embodiment of the present invention, the recommended amounts of polyols are: 3% to 40% by weight of polyol 1 (glycerol, OH value = 10 mg KOH / g to 30 mg KOH / g), 40% to 70% by weight of polyol 2 (glycerol, OH value = 31 mg KOH / g to 40 mg KOH / g), 10% to 40% by weight of polyol 3 (glycerol, OH value = 41 mg KOH / g to 50 mg KOH / g), and 5% to 30% by weight of polyol 4 (glycerol, OH value = 51 mg KOH / g to 60 mg KOH / g), used in a mixed manner.

[0047] The amount of polyol 1 used is 3.0% to 40% by weight. If its amount is less than 3% by weight, the hardness may decrease; while if its amount exceeds 40% by weight, the hardness may increase and the vibration damping performance may decrease.

[0048] Specifically, polyol 1 is a polyol in which styrene monomer solids are added, in an amount of up to 40% by weight, because the solid content (30% to 50%) affects the hardness, open-cell characteristics and viscosity of the raw material.

[0049] The preferred amount of polyol 2 is 40.0% to 70.0% by weight. If its amount is less than 40% by weight, the resilience may be significantly reduced; while if its amount exceeds 70% by weight, the hardness may be reduced.

[0050] The preferred amount of polyol 3 is 10.0% to 40.0% by weight. If its amount is less than 10% by weight, the vibration transmission rate may increase; while if its amount exceeds 40% by weight, the compression set may decrease.

[0051] The preferred amount of polyol 4 is 5.0% to 30.0% by weight. If its amount is less than 5% by weight, the vibration transmission rate may increase; while if its amount exceeds 30% by weight, the elasticity and compression set may decrease.

[0052] Meanwhile, the chain extender used is a mixture of chain extender 1 (diethanolamine, OH value = 1500 mg KOH / g to 2500 mg KOH / g) and chain extender 2 (1,4-butanediol, OH value = 500 mg KOH / g to 1500 mg KOH / g), and the crosslinking agent is triethanolamine (OH value = 1500 mg KOH / g to 2500 mg KOH / g).

[0053] The reason for using chain extenders and crosslinkers is that polyols alone cannot meet the performance requirements of the product, and because physical and mechanical properties such as tensile strength and tear strength exhibit different tendencies depending on the use of chain extenders and crosslinkers in the product manufacturing process, these components are important raw materials that must be added.

[0054] The use of chain extenders and crosslinking agents can increase the crosslinking strength between molecules, thereby playing an important role in improving conventional physical properties such as tensile strength and tear strength, as well as enhancing hydrolysis resistance, enabling the product to maintain its performance under high temperature and high humidity conditions.

[0055] However, if only the performance required for the final product is met, productivity can be reduced due to closed-cell formation and flowability issues. Therefore, the amount of chain extender 1 (diethanolamine, OH value = 1500 mg KOH / g to 2500 mg KOH / g) is 1% to 10% by weight. If its amount is less than 1% by weight, tensile strength and tear strength may deteriorate; while if its amount exceeds 10% by weight, excessive closed-cell formation may occur, resulting in a sharp decrease in productivity.

[0056] The amount of chain extender 2 (1,4-butanediol, OH value = 500 mg KOH / g to 1500 mg KOH / g) is 0.1% to 1% by weight. If its amount exceeds 1% by weight, the flowability may decrease.

[0057] The amount of the crosslinking agent triethanolamine (OH value = 1500 mg KOH / g to 2500 mg KOH / g) used is 1% to 5% by weight. If its amount exceeds 5% by weight, the flowability may decrease, thereby increasing the defect rate.

[0058] Furthermore, the polyurethane reaction occurs through the contact and transformation of two liquid materials into a solid, not merely through the reaction between isocyanate and polyol. The catalysts required to lower the activation energies of these two reactions are the polyurethane curing catalyst and the foaming catalyst. The stable production of polyurethane foam products depends on the phase ratios of the two catalysts used.

[0059] The polyurethane curing catalyst is a mixture containing 33% by weight of triethylenediamine and 66% by weight of dipropylene glycol, in an amount ranging from 0.1% to 3% by weight.

[0060] The foaming catalyst is diethyltoluene diamine (DETDA), and its dosage is from 0.1% to 2% by weight.

[0061] In order to cure the polyurethane foam sound-absorbing lining of the present invention within a limited time, the amount of polyurethane curing reaction catalyst is up to 3% by weight and the amount of foaming catalyst is up to 2% by weight.

[0062] The recommended dosages of the polyurethane curing reaction catalyst and the foaming catalyst are 0.1% to 3.0% by weight and 0.1% to 2.0% by weight, respectively. If the dosage is below the lower limit of the recommendations, the curability may deteriorate, leading to reduced productivity; while if the dosage exceeds the upper limit of the recommendations, the flowability may decrease, resulting in pore defects.

[0063] Foaming agents can be broadly classified into physical foaming agents and chemical foaming agents; this article refers to chemical foaming agents. Since the amount of foaming agent used determines the reaction rate, curing properties, and free foam density, its dosage depends on production conditions and is within a maximum range of 5% by weight. In this invention, water is used as the foaming agent.

[0064] Typically, the amount of foaming agent used is between 1.0% and 5.0% by weight. If the amount used is less than 1.0% by weight, the foaming rate may decrease, resulting in the inability to achieve the desired density. On the other hand, if the amount used exceeds 5.0% by weight, all physical properties may deteriorate due to over-foaming.

[0065] The foam stabilizer is a polyether-modified polysiloxane that has emulsifying properties, facilitates the reaction between MDI and polyols, reduces surface tension to form fine pores, and further stabilizes these pores. The amount of foam stabilizer used depends on production conditions and is within a maximum range of 3%.

[0066] Generally, the amount of foam stabilizer used is 0.1% to 3.0% by weight. If its content is less than 0.1% by weight, polyurethane foam may not be formed; while if its content exceeds 3.0% by weight, excessive closed-cell formation may occur, resulting in reduced productivity.

[0067] Meanwhile, in this invention, the polyisocyanate is a mixture of MDI comprising 4% to 70% by weight of monomeric MDI (MMDI), 4% to 70% by weight of carbodiimide-containing MDI (CMDI), and 10% to 80% by weight of polymeric MDI (PMDI).

[0068] Each raw material has inherent properties in terms of hardness, flowability, and curability. By combining these properties, the desired chemical bonding structure can be achieved.

[0069] Specifically, to maximize vibration reduction, it is necessary to use 4% to 70% by weight of monomeric MDI (MMDI), 4% to 70% by weight of carbodiimide-containing MDI (CMDI), and 10% to 80% by weight of polymeric MDI (PMDI).

[0070] The dosage of monomeric MDI (MMDI) and carbodiimide-containing MDI (CMDI) are both in the range of 4% to 70% by weight. If the content is less than 4% by weight, excessive closed-cell formation may occur, thereby reducing productivity; while if the content exceeds 70% by weight, excessive open-cell formation may occur, thereby preventing normal foam formation and increasing the defect rate.

[0071] The typical dosage of polymeric MDI (PMDI) is 10.0% to 80.0% by weight. If the dosage is less than 10% by weight, the tensile strength and tear strength may decrease sharply; if the dosage exceeds 80% by weight, the hardness may increase sharply.

[0072] Furthermore, another aspect of the present invention provides a method for forming a polyurethane foam sound-absorbing liner inside a tire, comprising preparing a polyol premix composition comprising 3% to 40% by weight of polyol 1 (glycerol, OH value = 10 mg KOH / g to 30 mg KOH / g), 40% to 70% by weight of polyol 2 (glycerol, OH value = 31 mg KOH / g to 40 mg KOH / g), and 10% to 40% by weight of polyol 3 (glycerol, OH value = 41 mg KOH / g). 5% to 30% by weight of polyol 4 (glycerol, OH value = 51 mg KOH / g to 60 mg KOH / g), 1% to 10% by weight of chain extender 1 (diethanolamine, OH value = 1500 mg KOH / g to 2500 mg KOH / g), 0.1% to 1% by weight of chain extender 2 (1,4-butanediol, OH value = 500 mg KOH / g to 1500 mg KOH / g), and 0.1% to 5% by weight of polyol 4 (glycerol, OH value = 51 mg KOH / g to 60 mg KOH / g), OH value = 500 mg KOH / g to 1500 mg KOH / g), OH value = 50 mg KOH / g to 50 mg KOH / g, ... The mixture comprises, by weight % crosslinking agent, 1 to 5 wt% foaming agent (water), 0.1 to 3 wt% polyurethane curing reaction catalyst, 0.1 to 1 wt% foaming catalyst, and 0.1 to 3 wt% foam stabilizer; and contains 4 to 70 wt% monomeric MDI (MMDI), 5 to 70 wt% carbodiimide-containing MDI (CMDI), and 10 to 80 wt% crosslinking agent, 1 wt% to 5 wt% foaming agent (water), 0.1 to 3 wt% polyurethane curing reaction catalyst, 0.1 to 1 wt% foaming catalyst, and 0.1 to 3 wt% foam stabilizer; and contains 1 wt% to 1 wt% crosslinking agent, 1 wt% to 5 wt% foaming agent (water), 0.1 to 3 wt% polyurethane curing reaction catalyst, 0.1 to 1 wt% foaming catalyst, and 0.1 to 3 wt% foam stabilizer. A certain percentage of polymeric MDI (PMDI) is used to prepare a polyurethane foam sound-absorbing lining composition for use inside a tire. The composition is liquid and is prepared by introducing 50 to 60 parts by weight of a curing agent composition into a foaming mixing chamber based on 100 parts by weight of a polyol premixed composition, and then mixing; and by spraying and foaming the liquid polyurethane foam sound-absorbing lining composition onto the inner surface of a tire 31 corresponding to the tire tread, and then curing it to form a polyurethane foam sound-absorbing lining 32.

[0073] Therefore, as [ Figure 1 ]to[ Figure 3 As shown, liquid polyurethane foam sound-absorbing lining composition is sprayed and foamed onto the inner surface of tire 31 through foaming nozzle 13a of foaming head 13 spaced at a predetermined distance from the inner surface of tire for a predetermined time period and at a predetermined discharge rate. The predetermined time period corresponds to the time it takes to rotate once on the inner surface of tire at a constant speed.

[0074] Specifically, it is important that when the liquid polyurethane foam sound-absorbing liner composition is sprayed and foamed onto the inner surface of the tire, a laser pointer 13b is used to mark the start point 32a and the end point 32b for spraying and foaming on the inner surface of the tire, so that the polyurethane foam sound-absorbing liner 32 does not overlap or have gaps at the start and end points.

[0075] Optionally, the method may include forming holes in a cured film formed on the surface of a polyurethane foam sound-absorbing liner 32 by punching holes with a needle brush or by marking design holes with a needle brush, the polyurethane foam sound-absorbing liner 32 being formed by spraying and foaming a liquid polyurethane foam sound-absorbing liner composition onto the inner surface of a tire and then curing it.

[0076] In addition, such as Figure 4 As shown, another aspect of the invention provides a low-noise tire 30 comprising a polyurethane foam sound-absorbing liner lined with a polyurethane foam sound-absorbing liner composition for use inside the tire, or manufactured by a method of forming a polyurethane foam sound-absorbing liner inside the tire.

[0077] The above description is merely an illustrative illustration of the technical spirit of the present invention. Those skilled in the art can make various modifications and variations without departing from the fundamental characteristics of the invention. Therefore, the embodiments and / or drawings disclosed herein are intended to explain the technical spirit of the invention, not to limit it, and the scope of the technical spirit of the invention should not be construed as being limited by these embodiments and / or drawings. The scope of protection of the present invention should be interpreted according to the claims, and all technical ideas equivalent to the scope of the claims should be interpreted as being included within the scope of the claims.

[0078] Industrial applicability This invention provides a low-noise tire, a polyurethane foam sound-absorbing liner composition for manufacturing the tire, and a method for forming a polyurethane foam sound-absorbing liner inside the tire using the composition. In order to reduce cavity resonance noise generated when the excitation force between the tire tread and the road surface during driving is transmitted to the tire's internal cavity and axle and manifests as interior noise, a liquid polyurethane foam sound-absorbing liner composition is simply, quickly, and precisely sprayed and foamed onto the inner surface of the tire corresponding to the tire tread, and then cured to form a polyurethane foam sound-absorbing liner, thereby improving the tire's low-noise performance and ultimately demonstrating industrial practicality.

Claims

1. A polyurethane foam sound-absorbing liner composition for use inside a tire, wherein, in order to reduce cavity resonance noise generated when the excitation force generated between the tire tread and the road surface during driving is transmitted to the internal cavity and axle of the tire and manifests as interior noise, a polyurethane foam sound-absorbing liner composition is simply, quickly, and precisely sprayed and foamed onto the inner surface of the tire corresponding to the tire tread, and then cured to form a polyurethane foam sound-absorbing liner, wherein the polyurethane foam sound-absorbing liner composition comprises, based on 100 parts by weight of a polyol premixed composition, 50 to 60 parts by weight of a mixed MDI (methylene diphenyl diisocyanate) curing agent composition, wherein the polyol... The alcohol premixed composition comprises: 3% to 40% by weight of polyol 1 (glycerol, OH value = 10 mg KOH / g to 30 mg KOH / g); 40% to 70% by weight of polyol 2 (glycerol, OH value = 31 mg KOH / g to 40 mg KOH / g); 10% to 40% by weight of polyol 3 (glycerol, OH value = 41 mg KOH / g to 50 mg KOH / g); 5% to 30% by weight of polyol 4 (glycerol, OH value = 51 mg KOH / g to 60 mg KOH / g); and 1% to 10% by weight of chain extender 1 (diethanolamine, OH value = 1500 mg KOH / g to 2500 mg KOH / g). 0.1% to 1% by weight of chain extender 2 (1,4-butanediol, OH value = 500 mg KOH / g to 1500 mg KOH / g); 0.1% to 5% by weight of crosslinking agent; 1% to 5% by weight of foaming agent, which is water; 0.1% to 3% by weight of polyurethane curing reaction catalyst; The mixed MDI (methylene diphenyl diisocyanate) curing agent composition comprises 0.1 wt% to 1 wt% of a foaming catalyst and 0.1 wt% to 3 wt% of a foam stabilizer, wherein the mixed MDI (methylene diphenyl diisocyanate) curing agent composition comprises 4 wt% to 70 wt% of monomeric MDI (MMDI), 4 wt% to 70 wt% of carbodiimide-containing MDI (CMDI), and 10 wt% to 80 wt% of polymeric MDI (PMDI).

2. The polyurethane foam sound-absorbing lining composition according to claim 1, wherein the crosslinking agent is triethanolamine with an OH value of 1500 mg KOH / g to 2500 mg KOH / g.

3. The polyurethane foam sound-absorbing lining composition according to claim 1, wherein the polyurethane curing reaction catalyst is a mixture comprising 33% by weight of triethylenediamine and 66% by weight of dipropylene glycol.

4. The polyurethane foam sound-absorbing lining composition according to claim 1, wherein the foaming catalyst is diethyltoluene diamine (DETDA).

5. The polyurethane foam sound-absorbing lining composition according to claim 1, wherein the foam stabilizer is a polyether-modified polysiloxane.

6. A method for forming a polyurethane foam sound-absorbing liner in a tire using a polyurethane foam sound-absorbing liner composition according to any one of claims 1 to 5, the method comprising: A polyol premix composition is prepared comprising 3% to 40% by weight of polyol 1 (glycerol, OH value = 10 mg KOH / g to 30 mg KOH / g); 40% to 70% by weight of polyol 2 (glycerol, OH value = 31 mg KOH / g to 40 mg KOH / g); 10% to 40% by weight of polyol 3 (glycerol, OH value = 41 mg KOH / g to 50 mg KOH / g); 5% to 30% by weight of polyol 4 (glycerol, OH value = 51 mg KOH / g to 60 mg KOH / g); and 1% to 10% by weight of chain extender 1 (diethanolamine, OH value = 1500 mg KOH / g to 2500 mg KOH / g). 0.1% to 1% by weight of chain extender 2 (1,4-butanediol, OH value = 500 mg KOH / g to 1500 mg KOH / g); 0.1% to 5% by weight of crosslinking agent; 1% to 5% by weight of foaming agent, which is water; 0.1% to 3% by weight of polyurethane curing reaction catalyst; 0.1% to 1% by weight of foaming catalyst and 0.1% to 3% by weight of foam stabilizer; Prepare a mixed MDI (methylene diphenyl diisocyanate) curing agent composition comprising 4 wt% to 70 wt% monomeric MDI (MMDI), 5 wt% to 70 wt% carbodiimide-containing MDI (CMDI), and 10 wt% to 80 wt% polymeric MDI (PMDI). A polyurethane foam sound-absorbing lining composition for use inside a tire is prepared, the composition being liquid and prepared by introducing 50 to 60 parts by weight of the curing agent composition into a foaming mixing chamber based on 100 parts by weight of the polyol premixed composition, and then mixing. as well as A polyurethane foam sound-absorbing liner is formed by spraying and foaming the liquid polyurethane foam sound-absorbing liner composition onto the inner surface of a tire corresponding to the tire tread, and then curing it.

7. The method of claim 6, wherein the liquid polyurethane foam sound-absorbing lining composition is sprayed and foamed onto the inner surface of the tire at a predetermined discharge rate for a predetermined time period through foaming nozzles spaced at a predetermined distance from the inner surface of the tire, the predetermined time period corresponding to the time required to rotate once on the inner surface of the tire at a constant speed.

8. The method of claim 7, wherein spraying and foaming the liquid polyurethane foam sound-absorbing lining composition onto the inner surface of the tire includes using a laser pointer to mark the start and end points of the spraying and foaming on the inner surface of the tire, such that the polyurethane foam sound-absorbing lining does not overlap or create gaps at the start and end points.

9. The method of claim 6, wherein the method comprises forming holes in a cured film formed on the surface of the polyurethane foam sound-absorbing liner by punching with a needle brush or by marking design holes with a needle brush, the polyurethane foam sound-absorbing liner being formed by spraying and foaming the liquid polyurethane foam sound-absorbing liner composition onto the inner surface of the tire and then curing it.

10. A low-noise tire, the low-noise tire comprising a polyurethane foam sound-absorbing liner lined with a polyurethane foam sound-absorbing liner composition according to any one of claims 1 to 5.

11. A low-noise tire, said low-noise tire being manufactured by the method according to any one of claims 6 to 9.

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