A hot vulcanized adhesive for PUE bonding and a method for preparing the same

Abstract

The application discloses a hot vulcanization adhesive for PUE bonding, which comprises the following materials in percentage by mass: modified phenolic resin 15-30%, curing agent 0.1-10%, catalyst 0.1-10%, silane coupling agent 0.1-10%, and the rest is solvent. Through special modification of the phenolic resin, the toughness and heat shock resistance of the prepared adhesive can be improved, and the dynamic fatigue life is improved as a whole.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of C09J161 / 06, and particularly relates to a hot vulcanized adhesive for PUE bonding and a preparation method thereof. BACKGROUND

[0002] In the field of elastomer bonding, in addition to the most common rubber bonding, there are some special elastomers such as PUE, which are widely used in light textile, heavy industry, logistics transportation, military industry, and mining industry.

[0003] For the application of bonding in the above-mentioned fields, the main PUE includes casting PUE (CPUE), thermoplastic PUE (TPUE), and mixing PUE (MPUE), among which the casting PUE is most widely used in the bonding field. The products matched with it include polyurethane casters, polyurethane rollers, and polyurethane wear-resistant liners. In the above-mentioned application process, the polyurethane products

[0004] are faced with severe use environments such as high temperature, high humidity, acid / alkali medium corrosion, etc., which puts high requirements on the adhesive, such as dynamic fatigue performance and heat shock resistance.

[0005] Chinese patent CN201610998043 discloses a hot vulcanized adhesive for bonding ceramic and elastomer, which has a silane-modified inorganic porous material supporting a phenolic compound as a bonding promoter, so as to form a high-strength transition layer between the elastomer and the hard ceramic, and promote the bonding of the adhesive to the high-strength hard ceramic. However, the resin has poor dynamic fatigue performance.

[0006] Chinese patent CN201810719573 discloses a preparation method of a filter adhesive sheet, which has very good dimensional stability, and the shrinkage rate of the adhesive sheet before and after curing is very low, so that the product is not prone to shrinkage and deformation during long-term use. The raw materials used in the preparation and use process are green, environmentally friendly, non-toxic, and safe to use, but the heat shock resistance is poor.

[0007] Chinese patent CN201810671086 discloses a phenolic resin adhesive sheet with high temperature resistance and solvent resistance. The phenolic resin adhesive sheet is modified by using monomers containing polybasic ring groups and unsaturated double bond groups, so as to change the curing mode of the phenolic resin, avoid the size shrinkage of the phenolic resin adhesive sheet during curing, and improve the dimensional stability of the adhesive sheet during use. However, it is not resistant to high temperature. SUMMARY

[0008] In order to solve the above problems, the application discloses a hot vulcanization adhesive for PUE bonding, which comprises the following raw materials in percentage by mass: modified phenolic resin 15-30%, curing agent 0.1-10%, catalyst 0.1-10%, silane coupling agent 0.1-10%, and the rest is solvent.

[0009] Preferably, the adhesive comprises the following raw materials in percentage by mass: modified phenolic resin 23%, curing agent 1.5%, catalyst 0.1%, silane coupling agent 0.15%, and the rest is solvent.

[0010] In an embodiment, the modified phenolic resin is selected from one or more of PVA modified phenolic resin, PVB modified phenolic resin, cashew oil modified phenolic resin, and o-cresol modified phenolic resin.

[0011] Preferably, the modified phenolic resin is selected from PVA modified phenolic resin, PVB modified phenolic resin, and cashew oil modified phenolic resin.

[0012] In an embodiment, the curing agent is selected from one or both of fatty amine curing agent and aldehyde curing agent.

[0013] Preferably, the fatty amine curing agent is selected from one or more of hexamethylenetetramine, trimethylhexamethylene diamine, trimethylhexane diamine, diethylamine, and hexane diamine.

[0014] Further preferably, the fatty amine curing agent is hexamethylenetetramine.

[0015] Preferably, the aldehyde curing agent is selected from one or more of urea-formaldehyde curing agent and polyformaldehyde curing agent.

[0016] Further preferably, the aldehyde curing agent is polyformaldehyde.

[0017] In an embodiment, the catalyst is selected from one or more of organic base catalyst, metal catalyst, complex catalyst, and rare earth catalyst.

[0018] Preferably, the catalyst is selected from one or more of stannous octoate, dibutyltin dilaurate, bismuth isooctoate, and zinc isooctoate.

[0019] Further preferably, the metal catalyst is zinc isooctoate.

[0020] In an embodiment, the silane coupling agent is selected from one or more of 7-aminopropyl triethoxysilane, epoxypropoxypropyl trimethoxysilane, anilinomethyl triethoxysilane, and vinyl trimethoxysilane.

[0021] Preferably, the silane coupling agent is selected from 7-aminopropyltriethoxysilane.

[0022] In one embodiment, the solvent is selected from one or more of toluene, isopropanol, trichloroethylene, ethanol, xylene, and propylene glycol methyl ether acetate.

[0023] Preferably, the solvent is a mixture of toluene, isopropanol, trichloroethylene, and ethanol.

[0024] More preferably, the solvent contains 25-35% toluene, 25-35% isopropanol, 10-30% trichloroethylene, and 10-30% ethanol by mass percentage.

[0025] In one embodiment, the raw materials for preparing the modified phenolic resin include: a composition of phenol and formaldehyde, a modifier, catalyst A, and solvent A.

[0026] More preferably, the modified material is selected from PVB, PVA, and cashew oil.

[0027] Preferably, the PVB, model BM-2, is purchased from Sekisui Chemicals.

[0028] Preferably, the PVA, model BP 05, is purchased from Changchun Chemical.

[0029] Preferably, the cashew oil is purchased from Shengquan.

[0030] Preferably, the catalyst A is ammonia water, and the amount of ammonia water added is 2-5% of the mass of phenol.

[0031] More preferably, the amount of catalyst A added is 2% of the mass of phenol.

[0032] Preferably, the molar ratio of phenol to formaldehyde is (1-1.25):1.

[0033] Preferably, the solvent A is ethanol, and the amount of ethanol added is 40%-50% of the mass of the modified phenolic resin.

[0034] In one embodiment, the method for preparing the modified phenolic resin includes the following steps:

[0035] S1: Phenol, formaldehyde, and catalyst A are added to a stirrer in a molar ratio and reacted at 80-90℃ for 1-2 hours.

[0036] S2: Add the modifier to step S1 and react for 1-2 hours.

[0037] S3: After vacuum dehydration, add solvent A to cool down and discharge the material.

[0038] A second aspect of the present invention provides a method for preparing the adhesive, the method comprising the following steps:

[0039] S1: Add modified phenolic resin to the solvent and stir evenly at 55-65℃;

[0040] S2: Add curing agent, catalyst and silane coupling agent to step S1, stir and disperse for 1-3 hours to obtain the final product.

[0041] In one embodiment, the preparation method specifically includes:

[0042] S1: Add modified phenolic resin to the solvent and stir until homogeneous at 60°C;

[0043] S2: Add curing agent, catalyst and silane coupling agent to step S1, stir and disperse for 2 hours to obtain the final product.

[0044] The applicant has discovered that currently used PUE products face the problem of high thermal shock and high dynamic fatigue life requirements in practical applications. The main reason is that the adhesive resin has insufficient toughness and high rigidity. By adding different modifiers to modify the phenolic resin, a multiphase dispersion system can be formed. Furthermore, through the modified phenolic resin route of this invention, the thermal shock resistance of the adhesive can be significantly improved, thereby improving the overall dynamic fatigue life.

[0045] Advantages:

[0046] 1. By modifying phenolic resin with PVA, PVB, and cashew oil, the thermal shock resistance of the resin is improved.

[0047] 2. By modifying phenolic resin with PVB resin and adjusting the addition ratio, the dynamic fatigue properties of adhesives can be improved.

[0048] 3. By adding appropriate modifiers to phenolic resin, the prepared adhesive can form a multiphase system, thereby improving the toughness of the adhesive.

[0049] 4. The process route for synthesizing adhesives according to the present invention can yield hot-cured adhesives with long dynamic fatigue life. Specific Implementation

[0050] Example

[0051] This embodiment discloses a method for preparing a modified phenolic resin, the raw materials of which include: a composition of phenol and formaldehyde, a modifier, ammonia, and ethanol.

[0052] The amount of ammonia added is 2% of the total mass of the phenol and formaldehyde composition and the modifier.

[0053] The molar ratio of phenol to formaldehyde is 1.25.

[0054] The amount of ethanol added is 45% of the mass of the modified phenolic resin.

[0055] This embodiment also discloses a method for preparing modified phenolic resin, including the following steps:

[0056] S1: Phenol, formaldehyde, and ammonia were added to a mixer in a molar ratio and reacted at 85°C for 1.5 hours.

[0057] S2: Add the modifier to step S1 and react for 1.5 h.

[0058] S3: After vacuum dehydration, add ethanol, cool down and discharge.

[0059] Table of raw material ratios for the preparation of phenolic resins in Examples 1-9:

[0060]

[0061] Examples 10-18 disclose the preparation of a heat-curing adhesive for PUE bonding. By mass percentage, the raw materials include: 23% modified phenolic resin from Examples 1-9, 1.5% curing agent, 0.1% catalyst, 0.15% silane coupling agent, and the remainder being solvent.

[0062] Examples 10-18 also disclose a method for preparing a heat-curing adhesive for PUE bonding, comprising the following steps:

[0063] S1: Add modified phenolic resin to the solvent and stir until homogeneous at 60°C;

[0064] S2: Add curing agent, catalyst and silane coupling agent to step S1, stir and disperse for 2 hours to obtain the final product.

[0065] Raw material proportions for heat-cured adhesives in Examples 10-18:

[0066]

[0067]

[0068] Performance testing

[0069] 1. PUE Adhesion Test

[0070] 1) Substrate preparation: Select iron sheets made of No. 45 steel, with specifications of 25*60*2mm, sandblasted with 80-mesh brown corundum, and degreased with solvent for later use.

[0071] 2) Apply adhesive by brush: Apply the adhesive of the above embodiment by brush, apply the undiluted solution twice (apply the second coat after the first coat has dried), and ensure that the dry film thickness (DFT) of all specimens is 15-25 μm. Dry at room temperature for 60 min for later use.

[0072] 3) PU preparation: Use polyether-type polyurethane prepolymer from Shandong Yinuowei Polyurethane Co., Ltd., in combination with Suzhou Xiangyuan MOCA chain extender, with a PU layer hardness of 95A.

[0073] 4) Pre-baking: Pre-baking the iron sheet coated with adhesive at 115℃ for 1.5-2 hours;

[0074] 5) Casting: Quickly pour the well-mixed polyurethane prepolymer and chain extender into the iron sheet that has been fixed and coated with adhesive.

[0075] 6) Vulcanization: Place the mold with the CPU cast above into the oven for full vulcanization. After the first stage of vulcanization, demold and then perform the second stage of vulcanization.

[0076] 7) Curing: After the two-stage vulcanization, the PU-like wheel products should be fully cured at room temperature for 24 hours before testing;

[0077] 8) Adhesion test: Referring to GB / T7760-2003, GB / T15254-2014, and ASTM D429-03METHOD B, the peel test is modified to a 45° peel test.

[0078] 9) Dynamic fatigue test: Refer to EN-125271998 and GB / T 14687-2011. Cast iron wheel core, apply the above adhesive, pour 90A polyester type PUE, 6-inch PU wheel, load 400KG, and conduct walking test (walking speed 5Km / h, obstacle 3.8mm), record the walking record when failure.

[0079] Bond strength test (thermal shock) - The specimen is baked in an oven at 100°C for 2 hours and then tested.

[0080]

[0081]

[0082] PU wheel walking test

[0083]

Claims

1. A heat-curing adhesive for PUE bonding, characterized in that, The adhesive comprises, by weight percentage, the following raw materials: 23% modified phenolic resin, 1.5% curing agent, 0.1% catalyst, 0.15% silane coupling agent, and the balance being solvent; The modified phenolic resin is a PVB-modified phenolic resin. The method for preparing the modified phenolic resin includes the following steps: S1: Phenol, formaldehyde, and catalyst A are added to a stirrer in a molar ratio and reacted at 80-90℃ for 1-2 h. S2: Add the modifier to step S1 and react for 1-2 h; S3: After vacuum dehydration, solvent A is added to cool the material before discharge; The molar ratio of phenol to formaldehyde is (1-1.25):1; solvent A is ethanol, and the amount of ethanol added is 40%-50% of the mass of the modified phenolic resin; The modified material is PVB; The mass ratio of the amount of the modified compound added to the amount of the phenol and formaldehyde composition added is 1:1; Catalyst A is ammonia water, and the amount of ammonia water added is 2-5% of the mass of phenol.

2. The adhesive according to claim 1, characterized in that, The curing agent is selected from one or two of fatty amine curing agents and aldehyde curing agents.

3. The adhesive according to claim 2, characterized in that, The fatty amine curing agent is selected from hexamethylenetetramine or trimethylhexamethylenediamine.

4. The adhesive according to claim 2, characterized in that, The aldehyde curing agent is selected from one or more of urea-formaldehyde curing agents and formaldehyde curing agents.

5. The adhesive according to claim 1, characterized in that, The catalyst is selected from one or more of organic base catalysts, metal catalysts, and complex catalysts.

6. The adhesive according to claim 5, characterized in that, The metal catalyst is selected from one or more of stannous octoate, dibutyltin dilaurate, bismuth isooctanoate, and zinc isooctanoate.

7. The adhesive according to claim 1, characterized in that, The silane coupling agent is selected from one or more of glycidoxypropyltrimethoxysilane, anilinemethyltriethoxysilane, and vinyltrimethoxysilane.

8. The adhesive according to claim 1, characterized in that, The solvent is selected from one or more of toluene, isopropanol, trichloroethylene, ethanol, xylene, and propylene glycol methyl ether acetate.

9. A method for preparing an adhesive according to any one of claims 1-8, characterized in that, The method includes the following steps: S1: Add modified phenolic resin to the solvent and stir evenly at 55-65℃; S2: Add curing agent, catalyst and silane coupling agent to step S1, stir and disperse for 1-3 hours to obtain the final product.

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