High-elasticity and high-viscosity adhesive rubber and preparation method thereof

Abstract

The present application relates to the field of rubber, and in particular to a high-elasticity and high-viscosity adhesive rubber and a preparation method thereof. The present application provides a high-elasticity and high-viscosity adhesive rubber, the raw materials of which include a rubber component and a filler. The rubber component contains at least a natural rubber and styrene-butadiene rubber composition accounting for 70% of the weight of the rubber component, a chloroprene rubber accounting for at least 6% of the rubber component, a thermoplastic elastomer accounting for at least 10% of the rubber component, and a polyvinyl butyral modified phenolic resin accounting for at least 4% of the weight of the rubber component; the filler contains at least 10-20% of the weight of the filler. In the above scheme, the amount of filler added can be increased while providing higher viscosity and elasticity.

Description

Technical Field

[0001] The present application relates to the field of rubber, and in particular to a high-elasticity and high-viscosity bonding rubber. Background Art

[0002] Adhesive rubber is an important industrial raw material. Its principle is to form a bonding structure between organic polymers, metals, glass and other components through polar interactions, molecular entanglement, van der Waals forces, etc., thereby achieving bonding between layers.

[0003] Adhesive rubber based on natural rubber is an important category of adhesive rubber. Natural rubber refers to a natural high molecular compound collected from the Brazilian rubber tree. Its main monomer is cis-1,4-isoprene, which has good elasticity and adhesion. On the basis of natural rubber, other rubber systems, modifiers and fillers are added to obtain adhesive rubber with good adhesion and elasticity.

[0004] In the rubber system, half of the fillers are inorganic particles, such as silica, titanium dioxide, various calcium carbonates, calcium sulfate or other metal oxides. The main purpose of adding them is to provide a certain strength and save costs. However, in the existing technology, the addition of fillers usually cannot exceed 40% of the total rubber component, otherwise it will affect the viscosity and elasticity of the system, and thus cause the bonding rubber to have poor properties. Summary of the invention

[0005] Based on the above problems, the purpose of this application is to provide a high-elasticity and high-bonding rubber with a high filler content, which can still maintain high viscosity and elasticity while providing good strength when the added mass of the filler is within the range of about 45% of the mass of the rubber component.

[0006] First, the present application provides a high-elasticity and high-viscosity adhesive rubber, the raw materials of which include the following components in parts by mass:

[0007] Rubber component 100 parts

[0008] Filler 45~55 parts

[0009] 3-8 parts of liquid paraffin

[0010] 5-10 parts of glyceryl monostearate

[0011] 1 to 5 parts of accelerator

[0012] 1-2 parts sulfur

[0013] 0.1-0.3 parts of p-phenylenediamine

[0014] The rubber component comprises at least 70% by weight of a natural rubber and styrene-butadiene rubber composition, at least 6% by weight of a chloroprene rubber, at least 10% by weight of a thermoplastic elastomer, and at least 4% by weight of a polyvinyl butyral-modified phenolic resin;

[0015] The filler contains at least 10 to 20% of the filler mass of glass fiber.

[0016] In the above scheme, the rubber component and the filler are used as the main components. It can be seen that in this scheme, the amount of filler added is very high, and in subsequent experiments, the large amount of filler added has no adverse effect on the elasticity, strength and bonding properties of the system. The reasons are as follows:

[0017] First, a certain amount of polyvinyl butyral modified phenolic resin is added to this scheme. Among many rubbers, this component has good bonding properties to inorganic fillers and strong viscosity. After experiments, polyvinyl butyral modified phenolic resin should account for at least 4% of the rubber component. When the amount added is too small, the viscosity enhancement effect is insufficient. On this basis, styrene-butadiene rubber and natural rubber are used as the main body, and chloroprene rubber and thermoplastic elastomer are added, which can ensure the good elasticity of the whole system, and chloroprene rubber provides viscosity between organic matter and organic matter. On the basis of the existing polyvinyl butyral phenolic modified resin for enhancing the viscosity between organic matter and inorganic matter, the combination of the two has a good viscosity promotion effect.

[0018] On the basis of the above, the components of the filler are adjusted, and 10-20% of glass fiber is added to the filler as a reinforcing material. On the one hand, compared with conventional filler components such as calcium carbonate, polyvinyl butyral modified phenolic resin has better bonding properties to glass fiber (or other glass material structures). Therefore, the addition of glass fiber can increase the cohesion of the bonding rubber as much as possible on the basis of slightly increasing the cost. At the same time, in this scheme, the amount of glass fiber added is controlled within the range of 10-20% of the filler, which can ensure the improvement of cohesion while reducing cost consumption. At the same time, excessive addition of glass fiber can easily lead to stratification of the internal structure of the plastic system, which in turn has an adverse effect on elasticity and toughness.

[0019] Furthermore, p-phenylenediamine is added to the system. On the one hand, p-phenylenediamine has certain reaction properties with polyvinyl butyral modified phenolic resin, which can improve the cross-linking degree of the system. At the same time, it provides benzene rings as a rigid structure in the reaction, combined with the flexible molecular chains on both sides, so that the resilience and stability between the molecular chains are better.

[0020] Liquid paraffin can adjust the overall viscosity in the system, so that the system can improve the processing performance of the bonding rubber and reduce its adhesion to the equipment on the basis of ensuring good viscosity.

[0021] In general, the above scheme ensures the adhesion, resilience and flexibility of the bonding rubber on the basis of adding a large amount of fillers, and has good market application prospects.

[0022] In the above scheme, the thermoplastic elastomer is preferably a nylon 6 elastomer, and more preferably a nylon 6 elastomer with a hardness of 70 to 80 Shore A, which can provide better elasticity, resilience and processing performance without reducing viscosity.

[0023] In the above scheme, the glass fiber is preferably not less than 5 mm and has an average diameter of 10 to 20 μm. Within this parameter range, the reinforcing effect of the glass fiber is better. The use of shorter glass fibers will lead to a certain degree of reduction in the strength of the system.

[0024] In the above system, in the natural rubber and styrene-butadiene rubber composition, preferably, natural rubber accounts for at least 60% of the mass of the rubber component. Compared with styrene-butadiene rubber, natural rubber has better flexibility and elasticity, and because it does not have an aromatic ring structure, its addition can enhance the entanglement between molecules. In this system, natural rubber has better connectivity, entanglement and compatibility than styrene-butadiene rubber. At the same time, not adding styrene-butadiene rubber will also lead to a certain decrease in overall strength, and reduced elasticity and resilience.

[0025] Preferably, the rubber component further comprises rosin resin accounting for 3 to 6% by weight of the rubber component.

[0026] In addition to the viscosity-increasing effect, the rosin resin in the system also improves the system's aging resistance and oxidation resistance. In addition, since the rosin resin has a large number of unsaturated groups, with the participation of sulfur, the rosin resin further improves the system's anti-delamination performance as a bonding layer.

[0027] Preferably, the filler comprises glass fiber accounting for 10-20% of the filler mass, and the remainder is hydrophobic white carbon black.

[0028] Although there is a small amount of polar rubber in the system, the use of hydrophobic silica still has better compatibility and uniformity in the system, so that toughness and strength can be taken into account, while the elasticity is also good. Compared with other elastomers (such as SBS or SIBS), the hard segment of nylon 6 elastomer is better integrated with other rubber systems, so it can better promote the elasticity of the system, but if its hardness is too small, it is easy to cause its poor rebound performance.

[0029] Preferably, dodecyl phosphate is also included, and the mass proportion of the dodecyl phosphate is 2 to 3 parts.

[0030] Dodecyl phosphate has the effects of surfactant, flame retardant and lubricant in the system and has good lubricating effect.

[0031] In addition, the present application also relates to a method for preparing the above-mentioned high-elasticity and high-viscosity adhesive rubber, comprising the following steps:

[0032] S1. Combine natural rubber and styrene-butadiene rubber, and mix them in an internal mixer at a temperature of 75 to 90° C. for 2 to 5 minutes;

[0033] S2, add polyvinyl butyral modified phenolic resin, glyceryl stearate, filler and liquid paraffin into the internal mixer, and continue mixing for 1 to 2 minutes;

[0034] S3, add p-phenylenediamine to the internal mixer, raise the temperature to 120-130°C, and continue mixing for 5-8 minutes;

[0035] S4. Add sulfur and accelerator to the above system, cool to 90-100°C, continue mixing for 1-2 minutes, and then discharge.

[0036] Optionally, the discharge temperature can be 170-180°C. The higher the temperature, the more favorable it is for smooth discharge, but it is also easy to have adverse effects on the system. After experiments, the rubber system can maintain good performance when the discharge is carried out at 170°C. If components such as thermal antioxidants are added, the discharge can still be good at a higher temperature, a higher temperature range can also be selected.

[0037] In the above scheme, natural rubber and styrene-butadiene rubber are first mixed. As a premixed system, it can be used as a basis for accommodating other components. A solvent-like structure is also formed at high temperature, which is convenient for other materials to be added and dispersed more evenly in the system. On the above basis, polyvinyl butyral modified phenolic resin, stearic acid glyceryl, filler and liquid paraffin are further added, wherein, liquid paraffin can improve the lubricity of the system after the temperature is increased, reduce the bonding of rubber on the equipment, and stearic acid glyceryl plays the role of a compatibilizer, which helps to mix more evenly between the organic phase and the inorganic phase, and then p-phenylenediamine and other components are added, and mixing is continued to form the cross-linked structure in the system, and the main structure is basically stable, and finally the bonding rubber is obtained by adding sulfur and accelerators. The bonding rubber prepared in the above scheme has better bonding performance, elasticity and mechanical strength. In addition, in step S1, alkyl phosphate can also be added as a surfactant, flame retardant, and lubricant.

[0038] In summary, the above scheme provides a high-elasticity and high-viscosity adhesive rubber, which increases the filler incorporation ratio by adding polyvinyl butyral modified phenolic resin and using glass fiber as part of the filler, thereby achieving the effects of high viscosity and high elasticity on the basis of reasonable cost control. DETAILED DESCRIPTION

[0039] The technical solution of the present application is further described through the following examples.

[0040] In this application, the bonding rubber prepared in each example is measured by the following scheme:

[0041] Adhesion strength: Two layers of the prepared adhesive rubber were bonded together, and their 180° peel strength was measured.

[0042] Rebound rate: measured in accordance with ASTM-F36.

[0043] The elongation at break and tensile strength are measured in accordance with GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber.

[0044] Example 1: In this example, the effects of different rubber components on the properties of the prepared adhesive rubber based on the filler with glass fiber are first studied, wherein the amount of filler added is fixed to 50% of the total amount of the rubber component, and 20% of the filler is glass fiber, and the rest is hydrophobic white carbon black. Specifically, in this example, the component ratio of the overall material is as follows in parts by mass:

[0045] Rubber component 100 parts

[0046] 50 parts of filler;

[0047] 5 parts of liquid paraffin;

[0048] 5 parts of glyceryl monostearate;

[0049] 3 parts of accelerator;

[0050] 2 parts of sulfur;

[0051] 0.1 part of p-phenylenediamine;

[0052] 2 parts of dodecyl phosphate.

[0053] Among them, the accelerator is accelerator NS. In the above system, antioxidants, anti-scorch agents, masterbatches and other components can also be added. A small amount of addition will not have a significant effect on the performance of the system.

[0054] The above system is actually a vulcanized rubber system. Regarding the amount of sulfur and accelerator in the vulcanized rubber, the amount of sulfur added is controlled at 1 to 2 parts, and the amount of accelerator added is controlled at 1 to 5 parts. It has a faster reaction rate and better reaction effect as a whole, and it is also easy to form a good degree of crosslinking in the system. Under normal circumstances, the addition of sulfur will increase the degree of crosslinking in the system and increase cohesion, but it will also reduce elasticity and processability, which will not be repeated in subsequent experiments.

[0055] In Example 1, the specific proportions of the rubber components in different experimental groups are shown in Table 1.

[0056]

[0057] The thermoplastic elastomer is nylon 6 thermoplastic elastomer, specifically nylon 6-polyvinyl alcohol elastomer, and its hardness is measured to be 70 Shore A.

[0058] The rosin resin is a commercially available natural rosin resin. In addition, through experiments, it is found that the influence of the properties of the terpene-modified rosin resin is small.

[0059] The glass fiber is made of alkali-free glass, with a length range of 5 to 10 mm and an average diameter of 17.2 μm.

[0060] At the same time, Example 1 also includes the following comparative examples:

[0061] Comparative Example 1: Based on Example 1-1, the polyvinyl butyral modified phenolic resin is replaced with unmodified bisphenol A phenolic resin.

[0062] Comparative Example 2, based on Example 1-1, the polyvinyl butyral modified phenolic resin is replaced by epoxy resin.

[0063] In Example 1, the preparation method of the bonding rubber is as follows:

[0064]

[0065] Through the above experiments, it can be seen that polyvinyl butyral modified phenolic resin (hereinafter referred to as modified phenolic resin) plays an important role in the system. Under high filler addition, not adding modified phenolic resin or replacing modified phenolic resin with unmodified bisphenol A phenolic resin or other resins will lead to a significant decrease in the viscosity of the system, and the rebound performance and elongation at break will become significantly brittle. Specifically, the modified phenolic resin should account for at least 4% of the mass proportion in the total system of rubber components, otherwise its miscibility and reinforcement effects are weak. In this scheme, there is no need to modify the filler (such as adding silane coupling agent, etc.) to achieve a good uniform mixing effect, which greatly reduces the production cost required for the bonding rubber.

[0066] On the basis of the above, there are certain requirements for the materials of other rubber components. The addition of rosin resin can greatly improve the bonding performance of the system. Rosin resin with a specific gravity of 3-6% can improve the viscosity of the system without affecting the overall strength. Chloroprene rubber has a good effect on the elasticity and viscosity of the system. For the specific gravity of natural rubber and styrene-butadiene rubber, when the mass of natural rubber accounts for more than 60%, the elasticity of the rubber system is better, and it does not affect the strength, and has a better effect. The addition of thermoplastic elastomer has a favorable effect on the overall strength, viscosity and elongation at break of the system.

[0067] In addition, the overall mass of the filler can be more than 45 parts, but should not exceed 55 parts. If it exceeds 55 parts, the solution of the present application is still difficult to ensure uniform mixing of the filler. Overall, the amount of filler added should be half the mass of the rubber component.

[0068] Example 2, based on Examples 1-9, the selection and proportion of glass fiber in the filler are adjusted. Specifically, in this example, glass fiber of the following specifications is selected and used:

[0069] A: Alkali-free glass, length range is 5-10 mm, average diameter is 17.2 μm;

[0070] B: Alkali-free glass, length range 10-20 mm, average diameter 19.4 μm;

[0071] C: Alkali-free glass, length range 5-10 mm, average diameter 25.5 μm;

[0072] D: Alkali-free glass, length range 2.5-5 mm, average diameter 14.2 μm;

[0073] E: Made of alkali-free glass, length range is 5-10 mm, average diameter is 10.7 μm.

[0074] In Example 2, the glass fiber selection and dosage and the overall dosage of fillers in different experimental groups are shown in Table 3.

[0075]

[0076] The experiment was carried out on Example 2, and the results are shown in Table 4.

[0077]

[0078] From the above experimental data, it can be seen that when the glass fiber length is too short, it will have a negative impact on the overall performance of the material. Specifically, it can no longer play an anchoring role in the system, which leads to a decrease in tensile strength and elongation at break. Although increasing the amount of glass fiber can improve the overall strength of the system, the glass fiber itself is more expensive, its hardness will increase, and its elongation at break will deteriorate.

[0079] Example 3. In this example, the type of thermoplastic elastomer used was adjusted. On the basis of Examples 1-9, the thermoplastic elastomer was replaced with the following thermoplastic elastomer in equal quantities, as shown in Table 5.

[0080]

[0081] The experiment was carried out on Example 3, and the results are shown in Table 6.

[0082]

[0083] It can be seen from the above experiments that when nylon 6 elastomer is selected as the thermoplastic elastomer, it has better overall performance.

[0084] Example 4, based on Examples 1-9, the amount of p-phenylenediamine used was adjusted, as shown in Table 7.

[0085]

[0086] From the above data, it can be seen that the addition of p-phenylenediamine significantly improves the strength of the system. The increase in the amount of p-phenylenediamine added can make the viscosity and elasticity of the adhesive rubber increase first and then decrease, and compared with the example without adding p-phenylenediamine, it has a significant improvement effect on both resilience and tensile strength. However, adding too much p-phenylenediamine will make the system hard and brittle, and the elongation at break and the rebound rate will decrease.

[0087] Example 5, based on Examples 1-9, the amount of dodecyl phosphate was further adjusted, and the specific experimental results are shown in Table 8.

[0088]

[0089] It can be seen from the data in Table 8 that adding dodecyl phosphate to the system can improve the tensile strength and rebound performance to a certain extent.

[0090] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A high elastic and high viscosity adhesive rubber, characterized in that: The raw materials are as follows by mass: Rubber component 100 parts Filler 45~55 parts 3-8 parts of liquid paraffin 5-10 parts of glyceryl monostearate 1 to 5 parts of accelerator 1-2 parts sulfur 0.1-0.3 parts of p-phenylenediamine The rubber component comprises at least 70% by weight of a natural rubber and styrene-butadiene rubber composition, at least 6% by weight of a chloroprene rubber, at least 10% by weight of a thermoplastic elastomer, and at least 4% by weight of a polyvinyl butyral-modified phenolic resin; The filler contains at least 10 to 20% of the filler mass of glass fiber.

2. The high-elasticity and high-viscosity adhesive rubber according to claim 1, characterized in that: The rubber component also includes rosin resin accounting for 3-6% of the weight of the rubber component.

3. The high-elasticity and high-viscosity adhesive rubber according to claim 1, characterized in that: The thermoplastic elastomer is nylon 6 elastomer.

4. The high-elasticity and high-viscosity adhesive rubber according to claim 3, characterized in that: The hardness of the nylon 6 elastomer is 70-80 Shore A.

5. The high-elasticity and high-viscosity adhesive rubber according to claim 1, characterized in that: The filler comprises glass fiber accounting for 10 to 20% of the filler mass, and the rest is hydrophobic white carbon black.

6. The high-elasticity and high-viscosity adhesive rubber according to claim 5, characterized in that: The length of the glass fiber is not less than 5 mm, and the average diameter is 10 to 20 μm.

7. The high-elasticity and high-viscosity adhesive rubber according to claim 1, characterized in that: It also includes dodecyl phosphate, and the mass proportion of the dodecyl phosphate is 2 to 3 parts.

8. The high-elasticity and high-viscosity adhesive rubber according to claim 1, characterized in that: In the natural rubber and styrene-butadiene rubber composition, the natural rubber accounts for at least 60% of the mass of the rubber component.

9. A method for preparing a high-elasticity and high-viscosity adhesive rubber according to any one of claims 1 to 8, characterized in that: The steps include: S1. Combine natural rubber and styrene-butadiene rubber, and mix them in an internal mixer at a temperature of 75 to 90° C. for 2 to 5 minutes; S2, add polyvinyl butyral modified phenolic resin, glyceryl stearate, filler and liquid paraffin into the internal mixer, and continue mixing for 1 to 2 minutes; S3, add p-phenylenediamine and other remaining components to the internal mixer, raise the temperature to 120-130°C, and continue mixing for 5-8 minutes; S4. Add sulfur and accelerator to the above system, cool to 90-100°C, continue mixing for 1-2 minutes, and then discharge.

10. The method for preparing a high-elasticity and high-viscosity adhesive rubber according to claim 9, characterized in that: In step S1, dodecyl phosphate is also added.

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