PP / EPDM material for metal frame paint-free sealing strip and preparation method thereof

Abstract

The application belongs to material improvement technology, and relates to a kind of automobile sealing strip materials, in particular to a kind of PP+EPDM material for sealing strip and a preparation method thereof, which can be effectively bonded with metal framework without brushing adhesive coating agent.The existing technology needs to use bottom coating agent when combining PP+EPDM dynamic vulcanization material with metal framework, usually needs to brush adhesive coating agent on the surface of stainless steel and bake to increase the adhesion of the two, which increases the process complexity of product forming and VOC emission of automobile sealing strip product and other problems.The application develops new components from the formula to prepare a kind of PP+EPDM material for sealing strip, which can be effectively bonded with metal framework without brushing adhesive coating agent.The PP / EPDM material of the application can achieve good adhesive force without adhesive when bonding with metal, and the bonding strength is greater than or equal to 6N / m under standard test method.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of material improvement, and relates to a material for a car sealing strip, in particular to a PP+EPDM material for a sealing strip and a preparation method thereof, which can be effectively bonded with a metal framework without brushing a rubber adhesive. BACKGROUND

[0002] The car sealing strip material has gone through the development process of EPDM rubber, soft PVC and PP+EPDM dynamic vulcanization TPV material. The PP+EPDM dynamic vulcanization elastomer material becomes a star in the car sealing strip industry because it can be recycled and reused and is convenient to process. The car framework material is usually stainless steel material or hard aluminum material, and the compatibility with PP+EPDM is poor (the surface energy of the PP+EPDM elastomer material is low), so it is usually necessary to brush a rubber adhesive on the surface of the stainless steel and then bake to increase the adhesion of the two. CN112175548A discloses that TPV needs to be bonded with metal materials together in many cases because of its wide application field. At present, the TPV adhesive is mainly realized by material surface pretreatment and special adhesive. The application provides a TPV easy to bond with adhesive and a manufacturing method thereof. By adding EMMA (ethylene methyl methacrylate copolymer) with good compatibility with the material in the formula and using naphthenic oil without adding a lubricant, the bonding effect is further improved, the problem of difficult bonding of TPV with adhesive is solved, and the product is bonded with metal using adhesive. CN110564341B discloses that the composite obtained by compounding TPV and metal is widely used in the fields of car sealing strips, door and window sealing parts and the like. At present, the adhesive mainly used for compounding TPV and metal in China is imported from Japan and Germany, and domestic products have not been reported. The application provides an adhesive for compounding thermoplastic elastomer and metal and a preparation method thereof. US20120110916A1 discloses an extrudable polymer for bonding metal with rubber and thermoplastic polymer, including a metal surface, a thin bonding layer of polymer material covering at least a selected portion of the metal surface, and an elastomer material received on the thin bonding layer of polymer material and exhibiting improved bonding with the metal through the thin layer of polymer material.

[0003] The prior art mainly produces sealing strips by coating the adhesive on the stainless steel or aluminum strip. Due to the introduction of the adhesive (glue), the process complexity of product forming is increased, the cost is increased, the defect rate caused by the adjustment problem of the adhesive is increased, and the VOC emission of the car sealing strip product is increased. SUMMARY

[0004] Existing technologies for bonding dynamically vulcanized PP+EPDM materials to metal frames typically require a primer, and typically require applying an adhesive to the stainless steel surface and baking to enhance adhesion. This increases the complexity of the product molding process and increases VOC emissions from automotive sealing strips. The present invention develops a novel formulation and composition to create a PP+EPDM material for sealing strips that effectively bonds to metal frames without the need for adhesive application.

[0005] The present invention adopts the following technical solutions.

[0006] A method for preparing a PP / EPDM material for a metal frame-free adhesive sealing strip comprises the following steps: subjecting a masterbatch to a vulcanizing reaction with a vulcanizing agent to obtain the PP / EPDM material for the metal frame-free adhesive sealing strip; the masterbatch comprises PP resin, EPDM rubber, operating oil, modified chlorinated polypropylene, zinc oxide, fillers, additives, and colorants.

[0007] In the present invention, PP resin, EPDM rubber, process oil, modified chlorinated polypropylene, zinc oxide, filler, auxiliary agent and colorant are melt-mixed to obtain masterbatch.

[0008] In the present invention, the modified chlorinated polypropylene is maleic anhydride-modified chlorinated polypropylene; preferably, the grafting rate of maleic anhydride is 0.5%-3%, preferably 1%-2%, and further preferably 1%-1.5%. As common sense, the grafting rate can be measured by existing technologies, such as acid-base titration.

[0009] Preferably, the degree of chlorination of the modified chlorinated polypropylene is 20%-30%; further preferably, the degree of chlorination of the modified chlorinated polypropylene is 22%-26%, which can be 22%, 23%, 24%, 25%, 26% or any value within the range.

[0010] In the present invention, the vulcanizing agent is a peroxide vulcanizing agent, including one or more of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (bis-25) and trimethylolpropane triacrylate (TMPTA). Preferably, the vulcanizing agent includes 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (bis-25) and trimethylolpropane triacrylate (TMPTA); further preferably, the weight ratio of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (bis-25) and trimethylolpropane triacrylate (TMPTA) is 1:(0.5-1.5).

[0011] Generally, zinc oxide is used as an acid absorber in phenolic vulcanization systems and is rarely used in peroxide vulcanization systems. The present invention enhances the bonding performance of the PP+EPDM material with metals such as stainless steel by introducing a modified CPP material in combination with zinc oxide and operating oil into the PP+EPDM elastomer system, so that the PP+EPDM elastomer material can achieve the function of adhesive-free extrusion of sealing strips, while meeting the performance requirements of products using conventional adhesives. In particular, the prepared PP / EPDM material for coating-free bonding with metal skeletons has high temperature resistance, low temperature resistance, and high and low temperature resistance.

[0012] In the present invention, the process oil includes paraffin oil.

[0013] In the present invention, the filler includes talc.

[0014] In the present invention, the colorant includes carbon black.

[0015] In the present invention, the weight ratio of PP resin, EPDM rubber, operating oil, modified chlorinated polypropylene, zinc oxide, vulcanizing agent, filler, additive and colorant is (10-30): (25-45): (20-40): (5-20): (1-5): (0.5-2): (10-20): (1-3): (0.5-2).

[0016] Preferably, the weight ratio of PP resin, EPDM rubber, operating oil, modified chlorinated polypropylene, zinc oxide, vulcanizing agent, filler, additive and colorant is (10-20): (25-35): (20-30): (10-20): (1-3): (1-2): (10-20): (1-3): (0.5-2).

[0017] Further preferably, the weight ratio of PP resin, EPDM rubber, operating oil, modified chlorinated polypropylene, zinc oxide, vulcanizing agent, filler, additive and colorant is (10-15): (25-30): (20-25): (15-20): (1.5-2.5): (1.3-2): (12-18): (1-2): (0.5-1).

[0018] In the present invention, the specific method of melt-mixing PP resin, EPDM rubber, process oil, modified chlorinated polypropylene, zinc oxide, filler, additive and colorant to obtain masterbatch is a conventional technology. The conventional extruder granulation method can be adopted, and other methods that can melt-mix PP resin, EPDM rubber, process oil, modified chlorinated polypropylene, zinc oxide, filler, additive and colorant can also be adopted to obtain masterbatch.

[0019] The specific way of obtaining the PP / EPDM material for the metal skeleton non-coating bonding type sealing strip by vulcanization reaction of the masterbatch and the vulcanizing agent in the application is a conventional technology, and the PP / EPDM material for the metal skeleton non-coating bonding type sealing strip can be obtained by using a conventional extruder granulation method or other methods that can make the masterbatch and the vulcanizing agent vulcanize.

[0020] The application discloses the PP / EPDM material for the metal skeleton non-coating bonding type sealing strip obtained by vulcanization reaction of the masterbatch and the vulcanizing agent.

[0021] The application discloses the application of the PP / EPDM material for the metal skeleton non-coating bonding type sealing strip in preparing a TPV product.

[0022] The application discloses the application of the PP / EPDM material for the metal skeleton non-coating bonding type sealing strip in preparing a TPV product.

[0023] The application discloses the application of the PP / EPDM material for the metal skeleton non-coating bonding type sealing strip in improving the bonding capacity of a TPV product.

[0024] The application discloses the application of the PP / EPDM material for the metal skeleton non-coating bonding type sealing strip in preparing a TPV product bonded with metal.

[0025] The application discloses a TPV product, and the raw material for preparing the TPV product comprises the PP / EPDM material for the metal skeleton non-coating bonding type sealing strip.

[0026] The application discloses a TPV metal composite product, which comprises metal and TPV material bonded with the metal, wherein the raw material for preparing the TPV material comprises the PP / EPDM material for the sealing strip without coating and bonding with the metal framework.

[0027] In the prior art, when PP+EPDM dynamic vulcanization material is combined with the metal framework, if a sealing strip is directly co-extruded by using the PP+EPDM elastomer material and stainless steel or aluminum, the elastomer material cannot be adhered to the surface of the stainless steel or aluminum, and thus the sealing strip cannot be formed. Therefore, in China, the sealing strip is mainly produced by coating the adhesive on the stainless steel or aluminum strip, and the process is long, the cost is high, and VOC volatilization exists. In the application, PP resin, EPDM rubber, operating oil, modified chlorinated polypropylene, zinc oxide, fillers, additives and colorants are melt-mixed to obtain masterbatch particles; the masterbatch particles are subjected to vulcanization reaction with a vulcanizing agent to obtain the PP / EPDM material for the sealing strip without coating and bonding with the metal framework. The material has excellent bonding force when bonded with metal such as stainless steel, especially without primer, and the bonding strength is as high as 9 N / m when the product of the application is directly combined with the stainless steel. Moreover, the PP / EPDM material for the sealing strip without coating and bonding with the metal framework has the properties of high-temperature resistance, low-temperature resistance and high-low temperature resistance. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a photo of the product of example 2 of the application and metal composite extrusion, and the bonding firmness.

[0029] Figure 2 It is a photo of the product of example 2 of the application and metal composite extrusion, and the bonding firmness.

[0030] Figure 3 It is a photo of the product of the prior art TPV and metal composite extrusion, and the bonding is poor. DETAILED DESCRIPTION

[0031] In China, PP+EPDM dynamic vulcanization material is combined with the metal framework by coating the adhesive on the stainless steel or aluminum strip to produce the sealing strip, and the process is long, the cost is high, and VOC volatilization exists. In the application, PP resin, EPDM rubber, operating oil, modified chlorinated polypropylene, zinc oxide, a vulcanizing agent, fillers, additives and colorants are used as raw materials, and two-step granulation is carried out to obtain the PP / EPDM material for the sealing strip without coating and bonding with the metal framework. The material has excellent bonding force when bonded with metal such as stainless steel, especially without primer, and the bonding strength is as high as 9 N / m when the product of the application is directly combined with the stainless steel. Moreover, the PP / EPDM material for the sealing strip without coating and bonding with the metal framework has the properties of high-temperature resistance, low-temperature resistance and high-low temperature resistance.

[0032] In the above technical solution, the modified chlorinated polypropylene is maleic anhydride-modified chlorinated polypropylene; preferably, the grafting rate of maleic anhydride is 0.5%-2.5%, preferably 1%-1.5%. As common sense, the grafting rate is measured by existing technology, such as acid-base titration.

[0033] Preferably, the degree of chlorination of the modified chlorinated polypropylene is 20%-30%; further preferably, the degree of chlorination of the modified chlorinated polypropylene is 22%-26%, which can be 22%, 23%, 24%, 25%, 26% or any value within the range.

[0034] In the above technical solution, the operating oil is paraffin oil; the vulcanizing agent is a peroxide vulcanizing agent; the filler is talcum powder with a particle size of 1500-5000 mesh, preferably 2000-3500 mesh; and the colorant is carbon black masterbatch.

[0035] In the above technical solution, the melt index of the PP resin is 0.2-3 g / 10 min, and the conditions are 230°C / 2.16 kg.

[0036] In the above technical solution, the ENB content of EPDM is 4-6%, the vinyl content is 60-70%, and the Mooney viscosity is 60-80 at 125°C.

[0037] In the above technical solution, the auxiliary agent includes one or more of an antioxidant, an anti-ultraviolet agent, and a lubricant.

[0038] In the present invention, the main ingredient formula of the PP / EPDM material for preparing the coating-free bonding type sealing strip with the metal frame is as follows, by mass percentage:

[0039] PP resin balance

[0040] EPDM rubber 25-45%

[0041] Operating oil 20-40%

[0042] Modified chlorinated polypropylene 5-20%

[0043] Talc 12-18%

[0044] Zinc oxide 1-3%

[0045] Preferably, the main ingredient formula of the PP / EPDM material for preparing the coating-free bonding sealing strip with the metal frame is as follows, by mass percentage:

[0046] PP resin balance

[0047] EPDM rubber 25-30%

[0048] Operating oil 20-25%

[0049] Modified chlorinated polypropylene 15-20%

[0050] Talc 12-18%

[0051] Zinc oxide 1.5-2.5%

[0052] In the present application, by mass percentage, with the main material as 100%, the small material formula is as follows:

[0053] Vulcanizing agent 0.5-2%

[0054] Auxiliary agent 1.5-2%

[0055] Carbon black master batch 0.5-1%

[0056] Preferably, by mass percentage, with the main material as 100%, the small material formula is as follows:

[0057] Vulcanizing agent 1.5-2%

[0058] Auxiliary agent 1.5-2%

[0059] Carbon black master batch 0.5-1%

[0060] In the above technical solution, the mass percentage of zinc oxide is 1%-3%; it can be 1%, 1.5%, 2%, 2.5%, 3% or any value within the range.

[0061] After mixing the materials used in the present application except the vulcanizing agent, directly enter the twin-screw extruder for melt mixing to make the first pass masterbatch, then pre-mix the masterbatch with the vulcanizing agent and enter the twin-screw extruder for vulcanization reaction extrusion to make finished particles; the diameter of the twin-screw equipment used can be 30-75mm, the speed can be 300-1200rpm, and the temperature can be 190-240℃ for processing, molding and granulation. The specific preparation method is prior art, which meets the TPV granulation requirements.

[0062] The following illustrates the technical progress of the present application through specific experiments. The raw materials used are all existing products, and the specific preparation operation and performance test are conventional technologies.

[0063] The materials involved in the examples and comparative examples are described as follows.

[0064] PP resin: polypropylene, grade 4220.

[0065] EPDM: grade 3092PM.

[0066] Process oil: paraffin-based white oil 300.

[0067] Maleic anhydride-modified CPP (chlorinated polypropylene) material, with a maleic anhydride grafting rate of 1%, is an existing product or prepared according to an existing method (reference: Synthesis and Properties of Maleic Anhydride-Grafted Chlorinated Polypropylene for Plastic Coatings). In the examples and comparative examples, existing chlorinated polypropylene (from Subi Chemical) was used as the raw material and grafted with maleic anhydride according to a conventional method. The details are as follows:

[0068] Modifier 1: Maleic anhydride grafted chlorinated polypropylene, chlorinated polypropylene is Subi Chemical SB-9P, chlorine content 24%, grafting rate 1%;

[0069] Modifier 2: Maleic anhydride grafted chlorinated polypropylene, chlorinated polypropylene is Subi Chemical SB-6300, chlorine content 36%, grafting rate 1%;

[0070] Modifier 3: Maleic anhydride grafted chlorinated polypropylene, chlorinated polypropylene is Subi Chemical SB-100P, chlorine content 17%, grafting rate 1%;

[0071] Comparative modifier: PP grafted maleic anhydride, Mitsui QF551, grafting rate 1%.

[0072] Curing agent: peroxide bis-25+TMPTA, mass ratio 1:1.

[0073] Zinc oxide: commercially available powder.

[0074] Talc: 2500 mesh.

[0075] Additives: including antioxidants, anti-UV agents, and lubricants. The antioxidants are 1010 and 168, each accounting for 0.2%, the anti-UV agents are 770 and 234, each accounting for 0.3%, and the lubricants are erucamide and PE wax, each accounting for 0.5%.

[0076] Carbon black colorant: carbon black masterbatch, brand 2718.

[0077] The raw material formulas of the examples and comparative examples are shown in Table 1, and the processing methods are as follows:

[0078] Except for the vulcanizing agent, the remaining materials are mixed conventionally and directly fed into a twin-screw extruder for melt mixing to form the first pass of masterbatch. The masterbatch is then mixed conventionally with the vulcanizing agent and fed into a twin-screw extruder for vulcanization reaction and extrusion to form finished particles. The twin-screw equipment used has a diameter of 55mm, a rotation speed of 700rpm, and a temperature of 190-240°C.

[0079] The testing methods of the materials are conventional techniques, and the examples and comparative examples are briefly described as follows:

[0080] Shore A hardness: According to ISO 868, A scale, 15s reading, requirement is 85+ / -5A.

[0081] Tensile strength: according to ISO 37, test speed 500 mm / min, requirement ≥ 7 MPa.

[0082] Tensile elongation at break: according to ISO 37, test speed 500 mm / min, requirement ≥ 400%.

[0083] Adhesion strength: the elastomer material of the example or the comparative example is conventionally co-extruded with stainless steel (without adhesive) into a sheet, and the adhesion strength is tested by a tensile testing machine, test speed 50 mm / min, requirement ≥ 6 N / m.

[0084] High temperature resistance test: according to the requirement of the standard of automobile parts QC-T15-1992, temperature storage at 85℃ for 24h, requirement not to be detached.

[0085] High-low temperature cycle: according to the requirement of the standard of automobile parts QC-T15-1992, temperature cycle at -30℃ and 80℃, each cycle period 24h, 10 cycles, requirement not to be detached.

[0086] Low temperature resistance storage: according to the requirement of the standard of automobile parts QC-T15-1992, storage at -30℃ for 24h, requirement not to be detached.

[0087] Warm water resistance: according to the requirement of the standard of automobile parts QC-T15-1992, warm water immersion at 40℃ for 240h, requirement not to be detached.

[0088] The present application can realize primer-free co-extrusion (TPV is co-extruded on a stainless steel skeleton or an aluminum skeleton), and the product after co-extrusion meets the production requirements: see Figure 1 , which is a product photo of the product of example 2 of the present application and a stainless steel skeleton conventionally co-extruded, and the TPV and the metal are well adhered without adhesive; see Figure 2 , which is a product photo of the product of example 2 of the present application and an aluminum skeleton conventionally co-extruded, and the TPV and the metal are well adhered without adhesive; see Figure 3 , which is a product photo of the product of the existing TPV (commonly used TPV material) which can be well adhered to the metal by adhesive on the existing production, and the existing TPV and the metal are not adhered without adhesive.

[0089] By comparing the experiments in Table 2 and combining the performance in production, the PP resin, EPDM rubber, operating oil, modified chlorinated polypropylene, zinc oxide, vulcanizing agent, filler, auxiliary agent and colorant are used as raw materials, two-step granulation is carried out, the PP / EPDM material for metal skeleton coating-free bonding sealing strip is obtained, the material has excellent bonding force with metal such as stainless steel and aluminum material, especially without primer, the product is directly compounded and extruded with metal, the bonding strength is high, and the PP / EPDM material for metal skeleton coating-free bonding sealing strip has high-temperature resistance, low-temperature resistance and high-low temperature resistance. In addition, the process flow of the application is simple, efficient and low in cost.

[0090] Table 1 Raw material formula of examples and comparative examples, kg

[0091]

[0092] Table 2 Performance of examples and comparative examples

[0093]

Claims

1. A method for preparing a PP / EPDM material for a metal frame free-coating adhesive sealing strip, comprising the following steps: subjecting a masterbatch to a vulcanizing reaction with a vulcanizing agent to obtain a PP / EPDM material for a metal frame free-coating adhesive sealing strip, characterized in that: The masterbatch comprises PP resin, EPDM rubber, operating oil, modified chlorinated polypropylene, zinc oxide, filler, additive and colorant; the modified chlorinated polypropylene is maleic anhydride-modified chlorinated polypropylene, the grafting rate of maleic anhydride is 0.5%-3%, and the chlorination degree of the modified chlorinated polypropylene is 20%-30%; the weight ratio of PP resin, EPDM rubber, operating oil, modified chlorinated polypropylene, zinc oxide, vulcanizing agent, filler, additive and colorant is (10-30): (25-45): (20-40): (10-20): (1-5): (0.5-2): (10-20): (1-3): (0.5-2).

2. The method for preparing the PP / EPDM material for the coating-free bonding sealing strip with the metal frame according to claim 1, characterized in that: The vulcanizing agent is a peroxide vulcanizing agent; the operating oil includes paraffin oil; the filler includes talc powder; and the colorant includes carbon black.

3. The PP / EPDM material for metal frame-free coating-free bonding sealing strip obtained by the preparation method of the PP / EPDM material for metal frame-free coating-free bonding sealing strip according to claim 1.

4. Use of the PP / EPDM material for coating-free bonding sealing strips with metal frames as claimed in claim 3 in the preparation of TPV products, or in improving the bonding ability of TPV products.

5. Use of the PP / EPDM material for coating-free bonding sealing strips with metal frames according to claim 3 in the preparation of automotive TPV products or TPV products bonded to metals.

6. A TPV product, the raw materials for its preparation include the PP / EPDM material for the coating-free bonding sealing strip with metal frame as claimed in claim 3.

7. A TPV metal composite product comprising a metal and a TPV material bonded to the metal, wherein: The raw materials for preparing the TPV material include the PP / EPDM material for the coating-free bonding sealing strip with the metal frame as described in claim 3.

Images