阅读说明：本技术 一种白车身专用橡胶型点焊密封胶及其制备方法 (Special rubber type spot welding sealant for body-in-white and preparation method thereof ) 是由 于虎 杨士勇 韩永德 于 2019-05-20 设计创作，主要内容包括：本发明涉及一种白车身专用橡胶型点焊密封胶,按重量分数计,包括如下组分：混炼橡胶45～55％、钛白粉4.5～5.5％、重质碳酸钙18～22％、纳米碳酸钙9～11％、橡胶硫化剂0.27～0.33％、稀释剂2.7～3.3％、硫化促进剂0.27～0.33％、增粘剂2.7～3.3％、液体阻燃剂3.6～4.4％、导电炭黑4.0～5.5％；所述混炼橡胶按重量分数计,包括如下组分：顺丁橡胶12.6～15.4％、丁腈橡胶12.6～15.4％、丁苯橡胶25.2～30.8％、液体聚丁二烯27～33％、重质碳酸钙4.5～5.5％、普通轻质碳酸钙4.5～5.5％、防老剂3.8～4.4％。本发明的橡胶型点焊密封胶以混炼橡胶为母料,不使用含PVC的组分,保证其点焊过程中无腐蚀成分挥发,使用无卤素的液体阻燃剂以及乙炔导电炭黑,在不增加粘度、不引入其他导电物质的同时达到阻燃导电的目的,并且配方中不含有机溶剂,绿色环保。(The invention relates to a special rubber type spot welding sealant for a body-in-white, which comprises the following components in parts by weight: 45-55% of mixed rubber, 4.5-5.5% of titanium dioxide, 18-22% of ground calcium carbonate, 9-11% of nano calcium carbonate, 0.27-0.33% of rubber vulcanizing agent, 2.7-3.3% of diluent, 0.27-0.33% of vulcanization accelerator, 2.7-3.3% of tackifier, 3.6-4.4% of liquid flame retardant and 4.0-5.5% of conductive carbon black; the mixed rubber comprises the following components in parts by weight: 12.6-15.4% of butadiene rubber, 12.6-15.4% of nitrile rubber, 25.2-30.8% of styrene butadiene rubber, 27-33% of liquid polybutadiene, 4.5-5.5% of heavy calcium carbonate, 4.5-5.5% of common light calcium carbonate and 3.8-4.4% of anti-aging agent. The rubber type spot welding sealant disclosed by the invention takes the mixed rubber as a master batch, does not use a component containing PVC (polyvinyl chloride), ensures that no corrosive component volatilizes in the spot welding process, uses a halogen-free liquid flame retardant and acetylene conductive carbon black, achieves the purposes of flame retardance and conductivity without increasing the viscosity and introducing other conductive substances, and is environment-friendly because the formula does not contain an organic solvent.)

1. The utility model provides a white special rubber type spot welding of automobile body is sealed glues which characterized in that, according to weight fraction, includes following component: 45-55% of mixed rubber, 4.5-5.5% of titanium dioxide, 18-22% of ground calcium carbonate, 9-11% of nano calcium carbonate, 0.27-0.33% of rubber vulcanizing agent, 2.7-3.3% of diluent, 0.27-0.33% of vulcanization accelerator, 2.7-3.3% of tackifier, 3.6-4.4% of liquid flame retardant and 4.0-5.5% of conductive carbon black;

the mixed rubber comprises the following components in parts by weight: 12.6-15.4% of butadiene rubber, 12.6-15.4% of nitrile rubber, 25.2-30.8% of styrene butadiene rubber, 27-33% of liquid polybutadiene, 4.5-5.5% of heavy calcium carbonate, 4.5-5.5% of common light calcium carbonate and 3.8-4.4% of anti-aging agent.

2. The rubber-type spot welding sealant according to claim 1, wherein said rubber vulcanizing agent is dicumyl peroxide.

3. The rubber-type spot welding sealant according to claim 1, wherein said diluent is 70# solvent oil or 90# solvent oil.

4. The rubber-type spot weld sealant according to claim 1, wherein the vulcanization accelerator is a mixture of tetramethylthiuram disulfide and 2-mercaptobenzothiazole.

5. The rubber-type spot welding sealant according to claim 1, wherein said tackifier is a mixture of an epoxy resin and a latent curing agent, said latent curing agent being one of boron trifluoride-amine complex, organic hydrazides or imidazoles.

6. The rubber-type spot welding sealant according to claim 1, wherein the liquid flame retardant is a halogen-free liquid flame retardant.

7. The rubber-type spot welding sealant according to claim 6, wherein the halogen-free liquid flame retardant is triisopropylphenyl phosphate.

8. The rubber-type spot welding sealant according to claim 1, wherein said conductive carbon black is acetylene black.

9. The rubber-type spot welding sealant according to claim 1, wherein said anti-aging agent is N, N' -xylyl-p-phenylenediamine.

10. A method for preparing a rubber type spot welding sealant according to any one of claims 1 to 9, characterized by comprising the steps of:

1) preparing mixed rubber: dicing the butadiene rubber, the nitrile rubber and the styrene butadiene rubber, putting the diced butadiene rubber, the nitrile rubber and the styrene butadiene rubber into a rubber mixing mill according to a weight ratio, and adjusting the roll spacing of the rubber mixing mill to enable the three types of rubber to be wrapped on a roller for mixing; accurately weighing liquid polybutadiene, heavy calcium carbonate, common light calcium carbonate and an anti-aging agent according to the weight parts, uniformly mixing to obtain a rubber material, adding a small amount of the rubber material on the mixed rubber for multiple times, performing cutting and turning operation to uniformly mix the rubber material, then discharging the rubber material, and standing for later use;

2) weighing titanium dioxide, heavy calcium carbonate, nano calcium carbonate, a rubber vulcanizing agent, a diluent, a vulcanization accelerator, a tackifier, a liquid flame retardant and conductive carbon black according to the weight parts, and stirring in a blending kettle to uniformly mix the titanium dioxide, the heavy calcium carbonate, the nano calcium carbonate, the rubber vulcanizing agent, the diluent, the vulcanization accelerator, the tackifier, the liquid flame retardant and the conductive carbon black to obtain a semi-finished product;

3) adding the semi-finished product obtained in the step 2) into a kneading machine, starting the kneading machine, adding the mixed rubber obtained in the step 1) into the kneading machine, kneading for 1-2 hours after the addition is finished, and controlling the working temperature of the kneading machine to be below 45 ℃ in the whole process of adding the mixed rubber and kneading;

4) closing the kneading machine cover, vacuumizing, and removing kneading bubbles to obtain the rubber type spot welding sealant.

Technical Field

The invention relates to a spot welding sealant and a preparation method thereof, in particular to a special rubber type spot welding sealant for a body-in-white and a preparation method thereof, belonging to the technical field of sealant formula and preparation method.

Background

The spot welding glue for automobile is mainly used in automobile welding production line, and has the main functions of sealing, damping and dispersing stress around welding spot to reach the functions of preventing dust, water, corrosion and damping, so as to prolong the service life of automobile.

From 10/1 in 2013, the implementation of national three-pack regulations of automobiles puts higher requirements on the corrosion prevention of the whole automobile, wherein the corrosion prevention of welding spots is concerned, the corrosion prevention of the overlapped parts of two steel plates on a welding surface is concerned, the two overlapped surfaces of the welding spots and the steel plates cannot be subjected to electrophoresis and paint spraying before a coating process, and the application of spot welding glue before welding is the best choice, so the application of the spot welding glue cannot be ignored.

The existing spot welding glue for automobiles on the market is mainly PVC (polyvinyl chloride) type, is high-temperature curing type spot welding glue, can emit hydrogen chloride gas when being baked at 140 ℃ to generate salt fog so as to corrode a welding spot, has poor flame retardance and electrical conductivity, poor adhesive force and elasticity, low peel strength, obvious spot welding reduction rate and static sealing influence on the spot welding strength.

Disclosure of Invention

The invention provides a rubber type spot welding sealant special for a body-in-white and a preparation method thereof, aiming at the current situation that the spot welding sealant for automobiles in the existing market emits hydrogen chloride gas during high-temperature baking and has poor performances.

The technical scheme for solving the technical problems is as follows:

the utility model provides a white special rubber type spot welding of automobile body is sealed glues, includes according to weight fraction as follows: 45-55% of mixed rubber, 4.5-5.5% of titanium dioxide, 18-22% of ground calcium carbonate, 9-11% of nano calcium carbonate, 0.27-0.33% of rubber vulcanizing agent, 2.7-3.3% of diluent, 0.27-0.33% of vulcanization accelerator, 2.7-3.3% of tackifier, 3.6-4.4% of liquid flame retardant and 4.0-5.5% of conductive carbon black;

the mixed rubber comprises the following components in parts by weight: 12.6-15.4% of butadiene rubber, 12.6-15.4% of nitrile rubber, 25.2-30.8% of styrene butadiene rubber, 27-33% of liquid polybutadiene, 4.5-5.5% of heavy calcium carbonate, 4.5-5.5% of common light calcium carbonate and 3.8-4.4% of anti-aging agent.

The nano calcium carbonate in the invention is light calcium carbonate with the particle size of less than or equal to 100nm, and the common light calcium carbonate is light calcium carbonate with the particle size of greater than or equal to 1000 nm.

Further, the rubber vulcanizing agent is dicumyl peroxide (DCP).

Further, the diluent is 70# solvent oil or 90# solvent oil.

Further, the vulcanization accelerator is a mixture of tetramethylthiuram disulfide (TMTD) and 2-Mercaptobenzothiazole (MBT).

Further, the tackifier is a mixture of an epoxy resin and a latent curing agent, and the latent curing agent is one of boron trifluoride-amine complex, organic hydrazides or imidazoles.

Further, the liquid flame retardant is a halogen-free liquid flame retardant, preferably triisopropylphenyl phosphate (IPPP).

Further, the conductive carbon black is acetylene carbon black.

Further, the anti-aging agent is N, N' -xylyl-p-phenylenediamine.

The rubber type spot welding sealant is characterized in that:

1) the mixed rubber is used as a master batch, PVC-containing components are not used, no corrosive component is volatilized in the spot welding process, halogen-free liquid flame retardant and acetylene conductive carbon black are used, the purposes of flame retardance and electric conduction are achieved while viscosity is not increased and other conductive substances are not introduced, and the formula does not contain an organic solvent, so that the environment is protected;

2) the mixed rubber adopts liquid polybutadiene to replace the traditional rubber plasticizer, so that the viscosity of the wet rubber is low, the plasticizer precipitation phenomenon is avoided, and the polybutadiene synchronously enters a crosslinking system in the heating and vulcanizing process, so that the strength of the rubber after curing is increased;

3) the butadiene rubber has particularly excellent cold resistance and elasticity, the butadiene rubber has more excellent wear resistance, heat resistance, aging resistance and vulcanization speed, the nitrile rubber has extremely good oil resistance and strong bonding force, the three rubber components complement each other after mixing, the overall performance is more excellent than that of single rubber, and the finished rubber has stronger adaptability to various environments in the using process.

The rubber type spot welding sealant has the beneficial effects that:

the spot welding sealant provided by the invention takes the mixed rubber as the master batch, the obtained product has long service life, the spot welding does not generate salt mist, and the spot welding sealant has high peel strength and shear strength, good heat resistance and good toughness.

The invention also claims a preparation method of the rubber type spot welding sealant, which comprises the following steps:

1) preparing mixed rubber: dicing the butadiene rubber, the nitrile rubber and the styrene butadiene rubber, putting the diced butadiene rubber, the nitrile rubber and the styrene butadiene rubber into a rubber mixing mill according to a weight ratio, and adjusting the roll spacing of the rubber mixing mill to enable the three types of rubber to be wrapped on a roller for mixing; accurately weighing liquid polybutadiene, heavy calcium carbonate, common light calcium carbonate and an anti-aging agent according to the weight parts, uniformly mixing to obtain a rubber material, adding a small amount of the rubber material on the mixed rubber for multiple times, performing cutting and turning operation to uniformly mix the rubber material, then discharging the rubber material, and standing for later use;

2) weighing titanium dioxide, heavy calcium carbonate, nano calcium carbonate, a rubber vulcanizing agent, a diluent, a vulcanization accelerator, a tackifier, a liquid flame retardant and conductive carbon black according to the weight parts, and stirring in a blending kettle to uniformly mix the titanium dioxide, the heavy calcium carbonate, the nano calcium carbonate, the rubber vulcanizing agent, the diluent, the vulcanization accelerator, the tackifier, the liquid flame retardant and the conductive carbon black to obtain a semi-finished product;

3) adding the semi-finished product obtained in the step 2) into a kneading machine, starting the kneading machine, adding the mixed rubber obtained in the step 1) into the kneading machine, kneading for 1-2 hours after the addition is finished, and controlling the working temperature of the kneading machine to be below 45 ℃ in the whole process of adding the mixed rubber and kneading;

4) closing the kneading machine cover, vacuumizing, and removing kneading bubbles to obtain the rubber type spot welding sealant.

The preparation method of the invention has the beneficial effects that:

(1) the components of the spot welding sealant are prepared into a semi-finished product in advance, so that the auxiliary materials are mixed more uniformly, and the quality uniformity of the spot welding sealant finished product is improved;

(2) the kneading process is more efficient than the grinding, stirring and other modes commonly used at present, the colloid is more uniform, and the mode of directly pumping air in the kneading process reduces the process steps of pumping air bubbles in the prior process.

Detailed Description

The principles and features of this invention are described below in conjunction with examples, which are set forth to illustrate, but are not to be construed to limit the scope of the invention.