Adhesive compositions for rubber and articles comprising them

Abstract

This invention relates to an adhesive composition for rubber and articles comprising the adhesive composition. The adhesive composition for rubber according to the invention comprises naturally derived sustainable ingredients, is applicable to a wide variety of rubbers, and exhibits excellent adhesion and fatigue resistance.

Description

Technical Field

[0001] This invention relates to adhesive compositions for rubber applicable to various types of rubber, and articles comprising such adhesive compositions. Background Technology

[0002] Rubber is a flexible material that can be easily deformed. Articles made of rubber are typically manufactured through vulcanization molding.

[0003] Vulcanization molding is a method of molding a rubber composition containing sulfur under high temperature and high pressure conditions, and can provide articles with various complex shapes while retaining the properties of rubber.

[0004] The conditions or duration required for vulcanization molding can vary depending on the size and shape of the article to be manufactured. For example, when manufacturing large and complex-shaped articles (such as large industrial tires) using a large amount of rubber composition, vulcanization molding is performed under more demanding conditions for a longer period of time to ensure adequate vulcanization inside the article.

[0005] However, when vulcanization molding is carried out for a long time, the inherent physical properties of rubber may deteriorate, and the fatigue performance of the product may become worse.

[0006] Therefore, a method is needed to prevent the physical properties of rubber from deteriorating under high temperature and high pressure conditions and to further improve the properties of rubber. Summary of the Invention

[0007] Technical issues

[0008] One object of the present invention is to provide an adhesive composition for rubber that is suitable for various types of rubber and exhibits excellent adhesion and fatigue resistance.

[0009] Another object of the present invention is to provide an article comprising an adhesive composition for rubber.

[0010] Technical solution

[0011] In the following, an adhesive composition for rubber and articles comprising the thereof will be described according to embodiments of the present invention.

[0012] Unless otherwise defined herein, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0013] As used in this article, the singular form also includes the plural form, unless the context clearly indicates otherwise.

[0014] As used herein, the term "comprising" specifies the presence of the stated features, regions, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, regions, wholes, steps, operations, elements, components, and / or groups.

[0015] This invention can be implemented in various forms and modified in various ways. Specific embodiments will be described and detailed below. However, this is not intended to limit the invention to the specific forms disclosed, and it should be understood that all modifications, equivalents, and alternatives falling within the scope of this invention are included.

[0016] When using terms such as “above,” “over,” “below,” or “adjacent” to describe the positional relationship between two parts, one or more intermediary elements may exist between the two parts, unless the terms “direct” or “immediately adjacent” are used.

[0017] When using terms such as “after,” “after,” “next,” or “before” to describe time relationships, intermediate steps may occur unless the terms “directly” or “immediately after” are used.

[0018] As used herein, the term "at least one" includes any and all combinations of one or more related items.

[0019] Terms including ordinal numbers such as "first" and "second" are used only to distinguish one component from another and do not limit the components. For example, a first component may be referred to as a second component without departing from the scope of the invention.

[0020] According to one embodiment of the present invention, a rubber adhesive composition is provided, comprising, based on a total composition of 100 parts by weight: 15 to 75 parts by weight of polyphenolic compounds; 0.5 to 10.5 parts by weight of the first basic compound; 0.05 parts by weight to 1.05 parts by weight of a second basic compound; and The remaining amount of solvent.

[0021] Conventionally, rubber adhesive compositions typically include resorcinol-formaldehyde condensates. However, resorcinol-formaldehyde condensates are harmful to human health, and a drawback is the difficulty in reprocessing adhesive wastewater containing resorcinol-formaldehyde condensates.

[0022] Therefore, as a result of the inventors' continued research, it has been confirmed that the rubber adhesive composition satisfying the above embodiments contains naturally derived sustainable ingredients and is environmentally friendly. This composition can be applied to various rubbers and exhibits excellent adhesion and fatigue resistance.

[0023] According to one embodiment of the present invention, the adhesive composition for rubber comprises a polyphenolic compound, an alkaline compound, and a solvent.

[0024] Polyphenols are a class of aromatic alcohols found in plants and possess multiple hydroxyl groups. For example, polyphenols can be obtained from plant bark, oak galls, leaves, etc.

[0025] Polyphenolic compounds can form their condensates through hydrogen bonding and / or hydrophobic interactions, thereby providing suitable cohesive strength to rubber adhesive compositions. Polyphenolic compounds can increase the tackiness of rubber adhesive compositions to improve adhesive strength with rubber. Furthermore, the polyphenolic compounds possess multiple aromatic rings, thus exhibiting excellent adhesion and fatigue resistance.

[0026] Preferably, the polyphenolic compound is a naturally derived compound. Naturally derived polyphenolic compounds are environmentally friendly as sustainable ingredients and exhibit superior adhesion compared to synthetically produced polyphenolic compounds.

[0027] For example, when analyzed by infrared spectroscopy, naturally derived polyphenolic compounds can be detected at 1650 cm⁻¹. -1 Absorption peaks are observed at the following wavenumbers. In contrast, the synthesized polyphenolic compounds show absorption peaks at approximately 1707 cm⁻¹. -1 An absorption peak is observed at a certain wavenumber, which is believed to be due to the formation of a greater number of C=O bond-containing units during synthesis compared to naturally derived polyphenolic compounds. As the number of C=O bonds in the molecule increases, the affinity for water increases, allowing compositions containing synthetic polyphenolic compounds to become relatively diluted and exhibit reduced adhesion. Therefore, naturally derived polyphenolic compounds are preferred.

[0028] Preferably, the polyphenolic compound can be at least one compound selected from tannic acid, gallotannins, and ellagitannins. More preferably, the polyphenolic compound can be tannic acid.

[0029] According to one embodiment of the present invention, the content of polyphenolic compounds may be 15 to 75 parts by weight based on 100 parts by weight of the total composition.

[0030] Specifically, the content of polyphenolic compounds can be 15 parts by weight or more, or 17.5 parts by weight or more, or 20 parts by weight or more; and can be 75 parts by weight or less, or 72.5 parts by weight or less, or 70 parts by weight or less.

[0031] To exhibit sufficient adhesion, the content of the polyphenol compound is preferably 15 parts by weight or more, or 17.5 parts by weight or more, or 20 parts by weight or more. However, when the content of the polyphenol compound is too high, the viscosity of the rubber adhesive composition may increase excessively. Therefore, the content of the polyphenol compound is preferably 75 parts by weight or less, or 72.5 parts by weight or less, or 70 parts by weight or less.

[0032] Preferably, based on a total composition of 100 parts by weight, the content of the polyphenol compound may be 15 to 75 parts by weight, or 17.5 to 75 parts by weight, or 17.5 to 72.5 parts by weight, or 20 to 72.5 parts by weight, or 20 to 70 parts by weight.

[0033] According to one embodiment of the present invention, the adhesive composition for rubber may include two or more basic compounds, and preferably may include a first basic compound and a second basic compound.

[0034] Preferably, the first basic compound may be at least one compound selected from ammonia (NH3), sodium carbonate (Na2CO3), potassium hydroxide (KOH), and magnesium hydroxide (Mg(OH)2). More preferably, the first basic compound may be ammonia.

[0035] The second basic compound can be sodium hydroxide (NaOH).

[0036] As described above, polyphenolic compounds form their condensates through hydrogen bonding and / or hydrophobic interactions, thereby providing suitable cohesive strength to the rubber adhesive composition. A first basic compound is used as a component acting as a crosslinking agent in the formation of the polyphenolic compound condensate, thereby enabling improved cohesive strength and excellent adhesive strength to be obtained in the rubber adhesive composition.

[0037] The second alkaline compound allows the rubber adhesive composition to have a hydrogen ion concentration (pH) within a suitable range, thereby promoting the condensation reaction of the polyphenol compound and the reaction between the polyphenol compound and the first alkaline compound during the preparation of the adhesive composition.

[0038] By simultaneously containing both a first alkaline compound and a second alkaline compound, the rubber adhesive composition ensures favorable conditions for the aggregation or crosslinking of polyphenolic compounds and exhibits stable adhesive properties relative to various rubbers. If the rubber adhesive composition contains only one of the first alkaline compound and the second alkaline compound, it may exhibit poorer adhesive strength than is expected in this invention.

[0039] According to one embodiment of the invention, based on a total composition of 100 parts by weight, a first basic compound may be included in an amount of 0.5 to 10.5 parts by weight, and a second basic compound may be included in an amount of 0.05 to 1.05 parts by weight.

[0040] Specifically, the content of the first alkaline compound may be 0.5 parts by weight or more, or 0.6 parts by weight or more, or 0.7 parts by weight or more, or 0.8 parts by weight or more, or 0.9 parts by weight or more, or 1.0 parts by weight or more; and 10.5 parts by weight or less, or 10.4 parts by weight or less, or 10.3 parts by weight or less, or 10.2 parts by weight or less, or 10.1 parts by weight or less. The content of the second alkaline compound may be 0.05 parts by weight or more, or 0.06 parts by weight or more, or 0.07 parts by weight or more, or 0.08 parts by weight or more, or 0.09 parts by weight or more, or 0.1 parts by weight or more; and 1.05 parts by weight or less, or 1.04 parts by weight or less, or 1.03 parts by weight or less, or 1.02 parts by weight or less, or 1.01 parts by weight or less, or 1 part by weight or less.

[0041] To create conditions conducive to the aggregation or cross-linking of polyphenolic compounds, the content of the first alkaline compound is preferably 0.5 parts by weight or more, and the content of the second alkaline compound is preferably 0.05 parts by weight or more. However, when the content of the alkaline compound is too high, the adhesiveness and fatigue resistance of the rubber adhesive composition may decrease. Therefore, the content of the first alkaline compound is preferably 10.5 parts by weight or less, and the content of the second alkaline compound is preferably 1.05 parts by weight or less.

[0042] Preferably, based on 100 parts by weight of the total composition, the content of the first basic compound may be 0.5 to 10.5 parts by weight, or 0.6 to 10.5 parts by weight, or 0.7 to 10.5 parts by weight, or 0.8 to 10.5 parts by weight, or 0.9 to 10.5 parts by weight, or 1.0 to 10.5 parts by weight, or 1.0 to 10.4 parts by weight, or 1.0 to 10.3 parts by weight, or 1.0 to 10.2 parts by weight, or 1.0 to 10.1 parts by weight, or 1.0 to 10 parts by weight. The content of the second basic compound may be 0.05 to 1.05 parts by weight, or 0.06 to 1.05 parts by weight, or 0.07 to 1.05 parts by weight, or 0.08 to 1.05 parts by weight, or 0.09 to 1.05 parts by weight, or 0.1 to 1.05 parts by weight, or 0.1 to 1.04 parts by weight, or 0.1 to 1.03 parts by weight, or 0.1 to 1.02 parts by weight, or 0.1 to 1.01 parts by weight, or 0.1 to 1.0 parts by weight.

[0043] The weight ratio of the first basic compound to the second basic compound (weight of the first basic compound: weight of the second basic compound) can be from 1:0.01 to 1:1.

[0044] To achieve the desired effect from the combined use of the first and second basic compounds, the weight ratio of the first to the second basic compound is preferably 1:0.010 or higher, or 1:0.011 or higher, or 1:0.012 or higher, or 1:0.013 or higher, or 1:0.014 or higher. However, when the weight ratio is too high (i.e., when the relative weight of the first basic compound is too low), the efficiency of the polyphenol compound condensation formation reaction and the efficiency of the reaction between the polyphenol compound and the first basic compound may decrease, and the physical properties of the rubber adhesive composition may become relatively poor. Therefore, the weight ratio of the first to the second basic compound is preferably 1:1 or lower, or 1:0.9 or lower, or 1:0.8 or lower, or 1:0.7 or lower, or 1:0.6 or lower.

[0045] Preferably, the weight ratio of the first basic compound to the second basic compound (weight of the first basic compound: weight of the second basic compound) can be 1:0.010 to 1:1, or 1:0.011 to 1:1, or 1:0.011 to 1:0.9, or 1:0.012 to 1:0.9, or 1:0.012 to 1:0.8, or 1:0.013 to 1:0.8, or 1:0.013 to 1:0.7, or 1:0.014 to 1:0.7, or 1:0.014 to 1:0.6.

[0046] According to one embodiment of the present invention, based on a total composition of 100 parts by weight, the remaining amount of solvent may be included together with the polyphenol compound, the first basic compound, and the second basic compound.

[0047] Preferably, the solvent can be water. The water can be purified water, distilled water, deionized water, softened water, etc.

[0048] According to one embodiment of the present invention, in the rubber adhesive composition, the polyphenolic compound may be tannic acid, the first alkaline compound may be ammonia, the second alkaline compound may be sodium hydroxide, and the solvent may be water.

[0049] According to one embodiment of the present invention, the adhesive composition for rubber may have a solid content of 26.5% by weight to 85.0% by weight.

[0050] As used herein, the term "solids content" refers to the amount of effective component remaining after the liquid component contained in a rubber adhesive composition has evaporated. The conditions for evaporating the liquid component are not particularly limited, and for example, evaporation can be carried out at a temperature of about 70°C to 100°C for 0.5 to 5 hours.

[0051] Specifically, the solid content of the rubber adhesive composition may be 26.5% by weight or more, or 27.0% by weight or more, or 27.5% by weight or more; and 85.0% by weight or less, or 84.0% by weight or less, or 83.0% by weight or less, or 82.0% by weight or less, or 81.0% by weight or less, or 80.0% by weight or less, or 79.0% by weight or less, or 78.0% by weight or less.

[0052] When the solids content of the rubber adhesive composition is too low, pinholes may occur during the coating process, and drying efficiency may decrease. Therefore, the solids content of the rubber adhesive composition is preferably 26.5% by weight or more, or 27.0% by weight or more, or 27.5% by weight or more. However, when the solids content is too high, the coatability of the composition may decrease, and the adhesive strength may become uneven due to the increased viscosity. Therefore, the solids content of the rubber adhesive composition is preferably 85.0% by weight or less, or 84.0% by weight or less, or 83.0% by weight or less, or 82.0% by weight or less, or 81.0% by weight or less, or 80.0% by weight or less, or 79.0% by weight or less, or 78.0% by weight or less.

[0053] More preferably, the solids content of the rubber adhesive composition may be from 26.5% to 85.0% by weight, or from 27.0% to 85.0% by weight, or from 27.0% to 84.0% by weight, or from 27.0% to 83.0% by weight, or from 27.0% to 82.0% by weight, or from 27.0% to 81.0% by weight, or from 27.0% to 80.0% by weight, or from 27.5% to 80.0% by weight, or from 27.5% to 79.0% by weight, or from 27.5% to 78.0% by weight.

[0054] The adhesive composition for rubber is applicable to a wide variety of rubbers.

[0055] For example, adhesive compositions for rubber can be used to bond rubber to rubber. As another example, adhesive compositions for rubber can be coated on the outer or inner surface of rubber to improve fatigue resistance.

[0056] Meanwhile, according to another embodiment of the present invention, the present invention provides an article comprising a rubber component and a coating formed on the rubber component, wherein the coating comprises an adhesive composition for rubber.

[0057] Rubber components can be any component that includes rubber material or is made of rubber.

[0058] A coating comprising a rubber adhesive composition can be formed on a rubber component. The coating can be formed on the outer or inner surface of the rubber component. The coating can be formed on at least a portion or all of the rubber component.

[0059] The coating can be formed by applying a rubber adhesive composition to a rubber component, attaching a layer containing a rubber adhesive composition to a rubber component, or impregnating a rubber component in a rubber adhesive composition.

[0060] The coating may further include a rubber reinforcing material and a rubber adhesive composition. The rubber reinforcing material may include organic or inorganic particles, fibers, fabrics, or combinations thereof.

[0061] There are no particular restrictions on the type of product, as long as it includes a rubber component. For example, the product can be a tire, hose, rubber belt, rubber sheet, or rubber rope.

[0062] By including a coating containing a rubber adhesive composition, the article exhibits excellent adhesion and fatigue resistance.

[0063] In addition, since the coating is formed from a rubber adhesive composition that satisfies the above composition, the coating can exhibit a dark brown inherent color and a silver tint.

[0064] According to one implementation scheme, such as when measured using a colorimeter, the coating can exhibit , and of Color value. Here, Color values ​​are components of a color coordinate system defined by the International Commission on Illumination (CIE), where... The value represents brightness. The value represents the degree of red and green, while The value indicates the degree of yellow and blue.

[0065] Specifically, since the coating is formed from a rubber adhesive composition that satisfies the above-described composition, when measured using a colorimeter, the coating can exhibit a colorimetric value of 49.00 to 55.00, or 49.50 to 55.00, or 49.50 to 54.50, or 50.00 to 54.50. Values; 9.00 to 13.00, or 9.05 to 13.00, or 9.05 to 12.95, or 9.10 to 12.95, or 9.10 to 12.90 Values; and 11.00 to 15.00, or 11.05 to 15.00, or 11.05 to 14.95, or 11.10 to 14.95. value.

[0066] According to another embodiment, the coating may have a color difference value that satisfies the following relationship 1 ( ): [Relation 1]

[0067] In relation 1, It is the color difference value exhibited by the coating, and is calculated using the following formula by measuring with a colorimeter. Chromaticity values ​​obtained: , here, , and The value is the chromaticity value exhibited by the reference coating used as the evaluation standard, and , and The value is the chromaticity value exhibited by the coating being measured.

[0068] Specifically, since the coating is formed from a rubber adhesive composition satisfying the above composition, the coating may have a color difference value of 4.50 or less, or 4.40 or less, or 4.30 or less, or 4.20 or less, or 4.10 or less. Preferably, the coating may have a color difference value of 0 to 4.50, or 0 to 4.40, or 0 to 4.30, or 0 to 4.20, or 0 to 4.10. ).

[0069] Beneficial effects

[0070] The rubber adhesive composition according to the invention comprises naturally derived sustainable components, is suitable for a variety of rubbers, and exhibits excellent adhesion and fatigue resistance. Detailed Implementation

[0071] Preferred embodiments are provided below to facilitate understanding of the invention. However, the following embodiments are for illustrative purposes only, and the invention is not limited thereto.

[0072] Examples and Comparative Examples

[0073] The compositions of the examples and comparative examples were prepared by mixing the components in the amounts shown in Tables 1 to 6 below. The amounts of each component are expressed in parts by weight, based on the total weight of 100 parts by weight of the composition. The compositions were prepared by mixing the components and stirring the mixture at room temperature (20°C) for 24 hours.

[0074] In this composition, tannic acid (provided by DUKSAN GENERAL SCIENCE) is used as a polyphenol compound, ammonia (provided by DUKSAN GENERAL SCIENCE) is used as a first basic compound, sodium hydroxide (provided by DUKSAN GENERAL SCIENCE) is used as a second basic compound, and distilled water is used as a solvent.

[0075] [Table 1]

[0076] [Table 2]

[0077] [Table 3]

[0078] [Table 4]

[0079] [Table 5]

[0080] [Table 6]

[0081] Experimental Example 1

[0082] Two laminates were prepared by sequentially layering a 0.6 mm thick rubber sheet, tire cord fabric, and another 0.6 mm thick rubber sheet. A coating was formed by applying a composition according to the examples and comparative examples to one of the two laminates to a thickness of 60 μm, and then stacking the other laminate on top of this coating. The resulting structure was tested at 160°C at 60 kg / cm². 2 It is vulcanized under pressure for 20 minutes and then cut into 1-inch widths to prepare samples.

[0083] The adhesive strength of the coating was evaluated by peel tests performed on the prepared samples using an Instron universal testing machine at 25°C and a crosshead speed of 125 mm / min. Adhesive strength was determined as the average of three measurements of the load at which peeling occurred in the sample. The measurements were normalized and expressed as relative values ​​based on the values ​​of the samples coated with the composition of Example 1.

[0084] Experimental Example 2

[0085] Two laminates were prepared by sequentially layering a 3.2 mm thick rubber sheet, tire cord fabric, and a 0.5 mm thick rubber sheet. A coating was formed by applying the composition according to the examples and comparative examples to the 0.5 mm thick rubber sheet of each laminate at a thickness of 60 μm, and the two laminates were then bonded together via this coating. The resulting structure was tested at 160°C at 60 kg / cm². 2 It is vulcanized under pressure for 20 minutes and then cut into 1-inch widths to prepare samples.

[0086] Dynamic adhesion tests were performed on the prepared samples using a rotary bending fatigue testing machine at 100°C and 180 rpm. After the tests, the adhesive strength of the samples was determined according to the following formula: [Calculation formula] Adhesion strength after fatigue (%) = [(Adhesion strength of the fatigued portion) / (Adhesion strength of the unfatigued portion)] × 100 Here, the fatigued and unfatigued parts can be distinguished by pre-applied markings, making each part identifiable before fatigue testing. Alternatively, even without such markings, fatigued and unfatigued parts can be distinguished by visual inspection.

[0087] The test was performed three times, and the average value was calculated. Based on the values ​​of the sample using the composition of Application Example 1, the calculated values ​​were normalized and expressed as relative values.

[0088] Experimental Example 3

[0089] Coated samples were prepared by coating a transparent release film with the composition according to the examples and comparative examples to a thickness of up to 60 μm and then drying it.

[0090] Coated sample Color values ​​were measured using a colorimeter (model: Color-Eye® 7000A, manufacturer: X-Rite). The color difference value was obtained from the measured color values ​​using the following formula (…). ): .

[0091] In the calculation formula, , and The value is the color value displayed by the reference coating sample (in this experiment, the sample from Example 1 was used as the evaluation standard), and , and The value is the color value displayed by the coating sample to be measured.

[0092] [Table 7]

[0093] [Table 8]

[0094] [Table 9]

[0095] [Table 10]

[0096] [Table 11]

[0097] [Table 12]

[0098] Referring to the table above, the samples treated with the adhesive composition according to the embodiments exhibited relatively excellent adhesion and fatigue resistance. In contrast, the samples treated with the adhesive composition according to the comparative examples exhibited much poorer adhesion and fatigue resistance.

[0099] Although the invention has been described above with reference to limited embodiments, it is not limited thereto. Various modifications and variations can be made by those skilled in the art within the scope of the invention and the equivalents of the claims set forth below.

Claims

1. A rubber adhesive composition, based on a total composition of 100 parts by weight, wherein the rubber adhesive composition comprises: 15 to 75 parts by weight of polyphenolic compounds; 0.5 to 10.5 parts by weight of the first basic compound; 0.05 parts by weight to 1.05 parts by weight of a second basic compound; and The remaining amount of solvent.

2. The adhesive composition for rubber according to claim 1, wherein, The polyphenolic compound is at least one compound selected from the group consisting of tannic acid, gallotannin, and inverse gallotannin.

3. The adhesive composition for rubber according to claim 1, wherein, The polyphenolic compound is tannic acid.

4. The adhesive composition for rubber according to claim 1, wherein, The first alkaline compound is at least one compound selected from the group consisting of ammonia (NH3), sodium carbonate (Na2CO3), potassium hydroxide (KOH), and magnesium hydroxide (Mg(OH)2).

5. The adhesive composition for rubber according to claim 1, wherein, The first basic compound is ammonia.

6. The adhesive composition for rubber according to claim 1, wherein, The second alkaline compound is sodium hydroxide (NaOH).

7. The adhesive composition for rubber according to claim 1, wherein, The weight ratio of the first basic compound to the second basic compound (weight of the first basic compound: weight of the second basic compound) is from 1:0.01 to 1:

1.

8. The adhesive composition for rubber according to claim 1, wherein, The solvent is water.

9. The adhesive composition for rubber according to claim 1, wherein, The rubber adhesive composition has a solids content of 26.5% to 85.0% by weight.

10. The adhesive composition for rubber according to claim 1, wherein, The polyphenolic compound is tannic acid, the first alkaline compound is ammonia, the second alkaline compound is sodium hydroxide, and the solvent is water.

11. An article comprising a rubber component and a coating formed on said rubber component, wherein, The coating comprises the adhesive composition of claim 1.

12. The article of claim 11, wherein, When measured with a colorimeter, the coating exhibits , and of Colorimetric value.

13. The article of claim 11, wherein, The coating satisfies the following relationship 1: [Relation 1] In relation 1, It is the color difference value exhibited by the coating, and is calculated using the following formula by measuring with a colorimeter. Chromaticity values ​​are obtained as follows: , in, and The value is the chromaticity value exhibited by the reference coating used as the evaluation standard, and and The value is the chromaticity value exhibited by the coating being measured.

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