TW202010785A - Dynamically crosslinked thermoplastic elastomer and manufacturing process thereof processing through two crosslinking treatment to improve flowability problems - Google Patents

Abstract

The present invention relates to a dynamically crosslinked thermoplastic elastomer and its manufacturing process. The main components of the dynamically crosslinked thermoplastic elastomer include ethylene-propylene-diene terpolymer rubber (EPDM), polypropylene (PP), and two kinds of crosslinking agents, and dynamically crosslinked thermoplastic elastomer is a mixture prepared through a dynamic crosslinking reaction. When preparing such a dynamically crosslinked thermoplastic elastomer, the first crosslinked agent is kneaded with some polypropylene and EPDM rubber for preliminary crosslinking reaction to form a first mixture, then the second crosslinked agent is kneaded with a new batch of polypropylene and ethylene-propylene-diene terpolymer rubber and the above mixture containing the first crosslinked agent to produce a dynamically crosslinked thermoplastic elastomer with high degree of crosslinking, better mechanical properties and processability. When a flowability problem appears in the preparation process, a part of the polypropylene can be replaced with low molecular weight and low modulus polypropylene to improve the flowability problem of the dynamic crosslinked thermoplastic elastomer (TPV), thereby enabling a wider range of related processing and molding methods and applications.

Description

Dynamic crosslinking thermoplastic elastomer and its manufacturing process

The invention relates to a dynamically cross-linked thermoplastic elastomer and its manufacturing process, in particular to a dynamically cross-linked thermoplastic elastomer obtained by the reaction of a double cross-linking agent and its manufacturing process. .

Thermoplastic elastomer (Thermplastic Elastomer, TPE), also known as thermoplastic rubber, is one of the most high-profile products among the raw materials of synthetic rubber in recent years. Thermoplastic elastomer TPE combines the characteristics of rubber elasticity and plastic processing conditions, and has both advantages. It can be processed by general thermoplastic molding machine and quickly manufactured into various products. It is used in medical, electronic parts, industrial construction, auto parts, daily necessities, etc., so the production efficiency is high. The waste materials and finished products produced in the process can be recycled and reused, which meets the requirements of environmental protection and can reduce costs. Thermoplastic elastomer also has the characteristics of high elongation, high resilience, low compression set, and low embrittlement temperature, which can be used to toughen and modify plastic materials.

Common thermoplastic elastomers (TPE) can be divided into six categories: thermoplastic polyurethane elastomers (Thermoplastic Urethane (TPU), polyolefin elastomers (thermoplastic polyolefinelastomers, TPO), dynamically cross-linked thermoplastic elastomers (thermoplastic vulcanizate, TPV), Polystyrene-based elastomers (styrenic block copolymers, TPS), polyetherester elastomers (thermoplastic copolyesters, TPC), and polyamide-based elastomers (thermoplastic polyamides, TPA). In recent years, dynamically cross-linked thermoplastic elastomers are particularly popular. Attention, because it combines the good elasticity of traditional elastomers and the recyclability of thermoplastic plastics, it is an environmentally friendly polymer material, so it is widely used in industry, especially automobiles and marine engines. Can replace acrylate (ACM) rubber market.

In order to have the characteristics of both plastic and rubber, the dynamically cross-linked thermoplastic elastomer material (thermoplastic vulcanizate, TPV) should contain both rubber (elastomer) and plastic (thermoplastic resin), and in the compound, the percentage of rubber is usually Much higher than plastic. Rubber can be used in combination with softening oil and plasticizers. Crosslinking agents and some crosslinking aids are also indispensable. In addition, in order to reduce costs or improve certain properties, some inorganic fillers are sometimes added.

When preparing dynamic cross-linked thermoplastic elastomer, the ingredients contained in the formulation, such as rubber and plastic, cross-linking agent, etc., are pre-mixed and dynamically cross-linked in the extruder. The so-called dynamic cross-linking refers to the melt blending of rubber and plastic At the same time, that is, when the rubber is dispersed in the plastic matrix, the rubber molecules are cross-linked to form a network structure, thereby improving the mechanical properties. The cross-linked rubber micro-zone mainly provides the elasticity of the blend, and the plastic matrix provides the thermoplastic moldability. The so-called rubber cross-linking/vulcanization refers to the cross-linking of rubber macromolecules to generate a chemical program with a three-dimensional network structure. After this procedure, the chemical structure of the rubber changes and its performance is improved. Therefore, TPV is a mixture of cross-linked rubber particles and plastic, the dispersed phase is rubber, and the continuous phase is crystalline plastic, which provides dimensional stability and thermoplasticity. Therefore, the dynamic cross-linked thermoplastic elastomer has a relatively low compression set, and The performance is close to traditional vulcanized rubber, which is unmatched by other types of TPE. The common continuous phase is usually polypropylene, and the dispersed phase is usually ethylene propylene rubber. This material has remarkable rubber characteristics. Compared with other types of thermoplastic elastomers, this type of thermoplastic elastomer (TPV) has good mechanical properties, low compression set, heat resistance, chemical resistance and low temperature resistance.

Commonly used elastomers in the market include natural rubber, ethylene/propylene copolymerized ethylene propylene monomer (Ethylene-propylene monomer, EPM), ethylene-propylene-non-conjugated diene rubber (EPDM, Ethylene Propylene rubber, Ethylene Propylene -diene-monomer (EPDM), styrene rubber such as Styrene/Butadiene Copolymer (SBR), Styrene Ethylene/Butylene Styrene rubber (SEBS), Nitrile Butadiene rubber (NBR), Acrylic rubber (ACM), Chlorinated Polyethylene (CPE), etc. The common plastics are polypropylene (PP), polyethylene (Polyethylene, PE), nylon (Polyamide, PA), polycarbonate (Polycarbonate, PC), and acrylonitrile-butadiene-styrene copolymer (Acrylonitrile Butadiene Styrene (ABS), Polystyrene (PS), Polybutylene terephthalate (PBT), polyethylene terephthalate (PET), etc., have been commercialized The formulas are EPDM/PP, NBR/PP, ACM/PP, SEBS/PS.

Dynamic cross-linked thermoplastic elastomer has good elasticity, resistance to compression deformation, corrosion resistance, aging resistance, weather resistance, wear resistance and oil resistance, easy dyeing, a wide range of application temperature and hardness, excellent processing performance, environmental protection requirements, light weight . It can be processed by thermoplastic processing methods such as: molding, injection, extrusion, etc., without the need to purchase new equipment. Compared with traditional rubber or plastic, these characteristics have certain advantages in terms of performance and cost.

Depending on the selected rubber/plastic/crosslinking agent composition, different properties of dynamically crosslinked thermoplastic elastomer products can be obtained. Other factors that affect the nature of the product include technical conditions and mixing equipment. The cross-linking agent can determine the dynamic cross-linking degree of the product and affect various physical and chemical properties of the thermoplastic elastomer. Crosslinking agents (also known as vulcanizing agents) can be divided into sulfur vulcanization systems and non-sulfur vulcanization systems, including near oxides, phenolic resins, amines, metal oxides, and radiation.

Although the sulfur vulcanization system has low cost, the vulcanization speed is slow, the time is long, the product has odor, and the high temperature crosslinking is unstable.

Peroxide can make the crosslinking reaction proceed at a lower temperature. TPV products obtained by vulcanization of oxide have superior heat resistance and lower compression. They have superior heat resistance and lower compression deformation. The color is lighter and easy to be colored. Dry, but peroxide will cause the degradation of plastic/resin molecules, and the product's physical and mechanical properties are poor (such as low tensile strength, tear strength, and poor wear resistance).

The phenolic resin crosslinking agent is used, so it has good mechanical strength, good melt strength and weather resistance, high temperature resistance, oil resistance and chemical resistance. The disadvantage is that the speed is slow, the vulcanization temperature is generally high, and chloride is required as the activator. The vulcanization process is complex. Different product batches have slight color difference and odor problems. In addition, the material has strong moisture absorption characteristics and needs to be dried before processing. .

Therefore, the dynamic cross-linked thermoplastic elastomer products produced by using different cross-linking agents have their own advantages and disadvantages. Therefore, how to choose a suitable rubber and plastic component, a crosslinking agent with high crosslinking efficiency and low side effects, improve the degree of crosslinking to improve various properties of dynamically crosslinked thermoplastic elastomers, such as mechanical properties, tensile properties, elongation, Compression deformation and/or oil resistance, etc., while striking a balance between mechanical properties and processability, are really important issues for the dynamically crosslinked thermoplastic elastomer industry.

In order to meet the above requirements and overcome the shortcomings of the conventional dynamic cross-linked thermoplastic elastomers, one object of the present invention is to provide a dynamic cross-linked thermoplastic elastomer (TPV) prepared using a dual cross-linking agent and a process for the dynamic cross-linking Thermoplastic elastomer (TPV) has excellent physical properties and a high degree of crosslinking.

Another object of the present invention is to provide a dynamically crosslinked thermoplastic elastomer (TPV), which further includes a low molecular weight and low stereoregular polypropylene (low molecular weight and low modulus polypropylene), when the produced dynamically crosslinked thermoplastic elastomer When the fluidity problem occurs in the body, the addition of such polypropylene can significantly improve and solve the fluidity problem.

To achieve the above objectives, the present invention provides a dynamically cross-linked thermoplastic elastomer (TPV), which is a mixture, including an elastomer, which is ethylene-propylene-non-conjugated diene rubber (EPDM), and the plastic is polypropylene (PP), two cross-linking agents, and additives.

To achieve the above objective, the present invention provides a process of dynamically cross-linked thermoplastic elastomer (TPV). First, a part of polypropylene (which may be a random copolymer and/or a single polymer), and a part of ethylene-propylene-non-co-polymer The conjugated diene rubber is added to the Banbury Mixer. After the two materials are melted evenly, the first crosslinking agent-phenolic resin is added to perform a preliminary crosslinking reaction to form the first mixture. When the torque increases, temporarily The reaction is stopped, so the first mixture still has cross-linking reactivity, the material is discharged, and the roller machine releases the tablets.

Then add another part of polypropylene and another part of ethylene-propylene-non-conjugated diene rubber into Banbury Mixer. After the two materials are melted evenly, add ultraviolet stabilizer, light stabilizer and anti-static agent. Additives such as oxidants, the first mixture and the second crosslinking agent-peroxide; as the torque increases to the maximum, continue to mix for 3 minutes, after the reaction reaches equilibrium, a second mixture is formed, that is, dynamic crosslinking Thermoplastic elastomer, blanking will roll out the machine.

When the prepared dynamic cross-linked thermoplastic elastomer (TPV) has the problem of insufficient fluidity, part of the polypropylene can be replaced with low molecular weight and low modulus polypropylene (low molecular weight and low modulus polypropylene) to make the second half The added polypropylene, or directly added, that is to increase the total amount of polypropylene. This low molecular weight polypropylene has the characteristics of low melting point, high fluidity and flexibility, which can improve the physical properties and processing properties of dynamically crosslinked thermoplastic elastomers. For example, at a specific processing temperature, it can solve the problem of low fluidity of dynamically crosslinked thermoplastic elastomers without affecting the compression set of the product, or it can increase the toughness of the final product, making its related processing methods and applications wider. .

The advantages and technical features of the present invention are: in the preparation of the dynamically cross-linked thermoplastic elastomer (TPV), a double cross-linking agent is used, and in the process of dynamically cross-linking thermoplastic elastomer, the first cross-linking agent and the partial polymerization are first Propylene and ethylene-propylene-non-conjugated diene rubber are kneaded to perform a preliminary cross-linking reaction to form the first mixture. When the torque increases, the reaction is temporarily stopped and the pieces are discharged. The second cross-linking agent and then the remaining polypropylene, ethylene - propylene - non - the first diene rubber and a mixture of a first crosslinker containing conjugated kneaded until the torque increased to a maximum mixing continued 3 In minutes, when the reaction reaches equilibrium, a dynamically crosslinked thermoplastic elastomer with a high degree of crosslinking is produced.

Figure 1 is an embodiment of the present invention, during the preparation process, the melt temperature and torque changes with time.

Dynamic cross-linking thermoplastic elastomer system is a new type of polymer material between rubber (elastomer) and plastic (resin). It has both the thermoplasticity of plastic and the elasticity of rubber and is easy to process. It is suitable to replace traditional rubber and plastic; generally includes at least An elastic rubber material and at least one thermoplastic. Among them, the elastic rubber is completely and uniformly dispersed in the thermoplastic, the thermoplastic is the continuous phase, and the elastic rubber forms the dispersed phase. The size of the elastic rubber particles is from 0.1 microns to about several microns, and the cross-link density is greater than 7×10-5 mol/ml. The particles also contain other additives. These large numbers of fine cross-linked rubber particles are dispersed in the plastic in a dispersed phase, and there should be no chemical bonding between the particles, so the dynamically cross-linked thermoplastic elastomer has high elasticity, excellent tensile properties and good compression set. The plastic particles coated around the elastic rubber particles form a continuous phase, providing excellent heat flowability and repetitive molding processability of the dynamically crosslinked thermoplastic elastomer. Therefore, the dynamically cross-linked thermoplastic elastomer is pressure-resistant and stretchable like rubber, thermoplastically processed like plastic, and has stable physical properties.

The dynamic cross-linked thermoplastic elastomer (TPV) described in the present invention is a mixture including cross-linkable (vulcanized) elastic rubber, ie, ethylene-propylene-non-conjugated diene rubber with or without oil exhibit. , Dispersed in a thermoplastic polyolefin such as polypropylene, which can be a random copolymer and/or a single polymer, with peroxide and phenolic resin as a cross-linking agent (vulcanizing agent) to make ethylene-propylene -Non-conjugated diene rubber undergoes a specific process to produce a dynamic cross-linking reaction and generate a dynamically cross-linked thermoplastic elastomer. In addition, when the dynamic cross-linked thermoplastic elastomer products have fluidity problems, low molecular weight polyolefin copolymers, such as low molecular weight and low stereoregular polypropylene (low molecular weight and low modulus polypropylene) systems can be added as modifiers, To improve the fluidity and surface smoothness of dynamically cross-linked thermoplastic elastomers.

Ethylene-propylene-non-conjugated diene rubber (EPDM), also known as EPDM rubber, is a ternary copolymer of ethylene, propylene and non-conjugated diene . Its characteristics are superior oxidation resistance and ozone resistance And corrosion resistance, low density, high filling . Polypropylene (PP) includes random copolymers of propylene and/or polypropylene monopolymers (also known as homopolymers). Polypropylene monopolymer is a semi-crystalline polymer with high crystallinity, which makes it have excellent mechanical properties, such as high rigidity, high tensile strength and good heat resistance. Because of its good fluidity, it is widely used in various processes. The low crystallinity of the polypropylene random polymer makes it transparent and improves the appearance of the product. Make the product softer. Compared with single polymers, the random copolymer has a lower melting point and crystallization temperature, making it easier to process.

In a preferred embodiment, the preparation procedure of the dynamically crosslinked thermoplastic elastomer according to the present invention includes step A: firstly, add some polypropylene, and ethylene-propylene-non-conjugated diene rubber to a ten thousand horsepower machine (Banbury Mixer), after the two materials are evenly melted, the first crosslinking agent-phenolic resin is added to perform a preliminary crosslinking reaction to form a first mixture (see Table 1), Step B: When the torque increases, the reaction is temporarily stopped Therefore, the first mixture still has cross-linking reactivity, and the material will be discharged from the roller machine. During mixing, the two phases of rubber and plastic are fully melted and blended, resulting in dynamic vulcanization, and the torque is also increased. The reason is that during dynamic vulcanization, under the action of strong mechanical shear and heat, the rubbers are highly cross-linked with each other and the viscosity changes At this time, it requires greater shear force and higher temperature to change from the continuous phase to the dispersed phase, and then distributed in the plastic (resin) with lower viscosity. Moreover, due to the action of strong shear force, the rubber particles become finer and more uniformly dispersed. The combined strength of the two phases increases and the power consumed increases, so that the torque becomes larger. See Figure 1 for torque changes during the manufacturing process.

Then perform step C: add another part, a new batch of propylene and ethylene-propylene-non-conjugated diene rubber, into the Wanbury Mixer, and after the two materials are melted evenly, add the ultraviolet stabilizer and light Stabilizers, antioxidants and other additives, the first mixture and the second cross-linking agent-peroxide , continue mixing ; Step D: After the torque increases to the maximum, continue mixing for 3 minutes to make the reaction reach equilibrium, forming a The second mixture (see Table 2), namely the dynamically cross-linked thermoplastic elastomer (TPV), is discharged to eject the roller.

Phenolic vulcanized resin is a kind of surface active agent. It cross-links with the double bond in ethylene-propylene-non-conjugated diene rubber by ion polymerization. The phenolic vulcanized resin refers to a concentrated masterbatch of phenolic vulcanized resin. In the process of preparing dynamically crosslinked thermoplastic elastomers, the plastic materials used sometimes have fluidity problems, that is, when heated, plastic molecules will not flow easily, making it more difficult to melt. When the phenolic vulcanized resin reacts directly with ethylene-propylene-non-conjugated diene rubber, it can improve the dispersibility of ethylene-propylene-non-conjugated diene rubber and stabilize the cross-linking reaction process of dynamically cross-linked thermoplastic elastomer , Resulting in excellent physical properties. The phenolic resin may be a phenolic resin with a methylol group, an alkylphenol-formaldehyde resin, or a halogen-substituted alkyl-substituted phenol-formaldehyde vulcanized resin, a halogen-substituted phenol, an alkyl-substituted phenol (preferably para-substituted ) Or unsubstituted phenol and aldehyde (preferably formaldehyde) are prepared by condensation in an alkaline medium, or by condensation of a bifunctional phenol diol.

As for peroxides, the cross-linking reaction occurs between the polymers through free radicals. During the reaction, the hydrogen peroxide in the peroxide or the generated free radicals will interact with the saturated bond and methylene bond (-CH ₂ ) It reacts with methyl bond (-CH ₃ ) to carry out free radical grafting and bridging reaction. The dynamic sulfurized olefin thermoplastic elastomer (TPV) with organic peroxide as crosslinking agent, the -CC- bond formed after crosslinking is better than that of -C-Sx formed by traditional sulfur crosslinking agent -C- bond is more stable, so it shows better heat resistance and aging resistance. Peroxides suitable for industrial production are: diacyl peroxides, tertiary alkyl peroxy acid esters, alkyl hydroperoxides, dialkyl peroxides, dialkyl peroxy ketals. Commonly used ones include dicumyl peroxide (DCP), benzoyl peroxide (BPO), 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane (BPMC) , 2,5-Dimethyl-2,5-bis(tert-butylperoxy)hexane (DBPMH), 1,3-bis(tert-butylperoxyisopropyl)benzene (BIPB), etc.

The components of the dynamically cross-linked thermoplastic elastomer (TPV) described in the present invention may further include low molecular weight and low modulus polypropylene (low molecular weight and low modulus polypropylene), which have the characteristics of low melting point, high fluidity and flexibility, etc. , Can improve the physical properties and processing performance of TPV. For example, at the processing temperature, the problem of low fluidity of the dynamically cross-linked thermoplastic elastomer (TPV) does not affect the compression set of the product, or increases the toughness of the final product, making the related processing methods and applications wider.

First embodiment:

Refer to Table 3, recipe number 3, take 12g polypropylene (random copolymer, single polymer or mixture thereof), and 20g ethylene-propylene-non-conjugated diene rubber (EPDM), in this example EPT-3045 manufactured by Mitsui Chemicals, Inc. of Japan is melted uniformly using a Banbury Mixer , and then 4 g of the first crosslinking agent-phenolic resin (Tackirol 201 manufactured by Taoka Chemical Industry) is added. The preliminary cross-linking reaction is carried out to form the first mixture, and its composition ratio range is shown in Table 1.

Then take 40g of polypropylene (random copolymer, single polymer or mixture thereof), and 100g of ethylene-propylene-non-conjugated diene rubber , and put it into a Wanbury Mixer to make it melt evenly. , And then add 2.5g of the second crosslinking agent-peroxide, 20g of the first mixture, and 1.5g of additives (including UV stabilizers, light stabilizers, antioxidants) to form a second mixture, and its composition ratio range, see Table 2: As the torque increases, the mixing is continued for 3 minutes, and the reaction reaches equilibrium until the dynamically crosslinked thermoplastic elastomer of the present invention is obtained. For the composition range of the dynamically crosslinked thermoplastic elastomer of the present invention, please refer to Table 3, where 20g of the first mixture is split into 12g of ethylene-propylene-non-conjugated diene rubber, 6g of polypropylene and 2g of phenolic vulcanized resin (The ratio is 60%, 30%, and 10%).

In a preferred embodiment of the present invention, the weight percentage of ethylene-propylene-non-conjugated diene rubber contained in the dynamically crosslinked thermoplastic elastomer is 55-70% (wt%), and the weight of polypropylene (PP) The percentage is 30-40%, the crosslinking agent weight percentage is 1-7%, contains phenolic resin and peroxide, the weight percentages are 0.3-4.2%, 0.6-3.6%, and the additive weight percentage is 0.6- 3.6%.

Table 4: Characteristics of each dynamic cross-linked thermoplastic elastomer (TPV) made with similar formulations but different cross-linking agents

Comparative Example 1 (Formula No. 1)

The preparation procedure is the same as the first embodiment of the present invention described above, but in step C: when adding additives such as ultraviolet stabilizers, light stabilizers, antioxidants, the first mixture and the second crosslinking agent, the second crosslinking agent is not added at all Oxide, instead add 5g of phenolic resin; so this example uses only phenolic resin as a crosslinking agent.

Comparative Example 2 (Formulation No. 2)

The preparation procedure is the same as the first embodiment of the present invention, but step A and step B in the first half of making the first mixture are omitted, and step C in the second half: adding additives such as ultraviolet stabilizers, light stabilizers, antioxidants, the first mixture and the second When the crosslinking agent is used, 2.0 g of peroxide is added as the crosslinking agent; that is, only peroxide is used as the crosslinking agent in this embodiment.

First embodiment (recipe number 3)

The formula No. 3 is the first embodiment of the present invention, including the first half of the steps A and B to make the first mixture, using phenolic resin as a cross-linking agent, and the second half of the steps to make the second mixture C and D, Use peroxide as a cross-linking agent; that is, use both phenolic resin and peroxide, double cross-linking agent.

See Table 4 for dynamically crosslinked thermoplastic elastomers (TPV) produced using different crosslinking agents, such as phenolic resins, peroxides, and mixtures thereof. It can be seen from the test data that when phenolic resin is used alone as the cross-linking agent, the product physical properties are the best (except for the melt index), but the degree of cross-linking is low and it is not easy to control; when only peroxide is used as the cross-linking agent, the physical properties It is the worst; while the combination of phenolic resin and peroxide crosslinking agents, the properties of the resulting dynamically crosslinked thermoplastic elastomer are not far away from the phenolic resin, but the degree of crosslinking is greatly improved, increasing to 99%.

Second embodiment (recipe number 4)

The preparation procedure is the same as the first embodiment of the present invention, but the ethylene-propylene-non-conjugated diene rubber (EPDM) used in the formulation/composition is changed from EPT-3045 of Japan Mitsui Chemicals Company to China Dow NORDEL ^™ EPDM IP 4640 manufactured by Dow Chemical Company.

Third embodiment (recipe number 5)

The preparation procedure is the same as the first embodiment of the present invention, but the ethylene-propylene-non-conjugated diene rubber (EPDM) used in the formulation/composition is changed from EPT-3045 of Japan Mitsui Chemicals Corporation to Kumho, South Korea KEP650 manufactured by Kumho Polychem Co., Ltd.

The composition of dynamically cross-linked thermoplastic elastomer (TPV) will affect the physical properties of the product. Therefore, non-oil-produced ethylene-propylene-non-co-monomers with different Mooney viscosity (ML(1+4)100℃) produced by different manufacturers—Mitsui Japan, China Dow, and Korea Kumho Chemical Co., are used. Conjugated diene rubber (EPDM), made of dynamically cross-linked thermoplastic elastomer, compare its physical properties, see Table 5. The physical properties of dynamically crosslinked thermoplastic elastomers are better than Kumho in Korea and Mitsui in Japan, while the melt index is higher in Mitsui in Japan. Melt flow index (MI), also known as melt flow rate (MFR), is a physical parameter that measures the flowability of materials, usually rubber or plastic materials, under certain temperature and pressure conditions, The larger the MI value, the better the fluidity, and the worse the worse, the unit is usually g/10min.

Shore hardness (Shore A scale) is measured according to the test method specified in ASTM D2240; Compression set (Cs) is measured according to the test method specified in ASTM D395; Melt flow index (MI) Measured according to the test method specified in ASTM D412.

In order to develop a dynamic cross-linked thermoplastic elastomer (TPV) suitable for injection molding, the ratio of the first mixture containing phenolic resin and peroxide added in the process was adjusted. The results are shown in Table 6.

Fourth embodiment (recipe number 6)

The preparation procedure is the same as the first embodiment of the present invention. The weight of the first mixture used in formula No. 3 is unchanged, but the peroxide is changed to 1 g.

Fifth embodiment (recipe number 7)

The preparation procedure is the same as the first embodiment of the present invention. The weight of the first mixture used in formula No. 3 is unchanged, but the peroxide is changed to 2 g.

Sixth embodiment (recipe number 8)

The preparation procedure is the same as the first embodiment of the present invention. The weight of the first mixture used in formula No. 3 is unchanged, but the peroxide is changed to 3 g.

Seventh embodiment (recipe number 9)

The preparation procedure is the same as the first embodiment of the present invention. The weight of the first mixture used in formula No. 3 is changed to 30 g, and the peroxide is changed to 1 g.

Eighth embodiment (recipe number 10)

The preparation procedure is the same as the first embodiment of the present invention. The weight of the first mixture used in formula No. 3 is changed to 30 g, and the peroxide is changed to 2 g.

Ninth embodiment (recipe number 11)

The preparation procedure is the same as the first embodiment of the present invention. The weight of the first mixture used in formula No. 3 is changed to 30g, and the peroxide is changed to 3g.

Referring to Table 6, it can be known from the experimental data that Example 8 has the best compression set. Since the fluidity of the dynamically cross-linked thermoplastic elastomer (TPV) of formula 8. is not suitable for injection molding, to solve this problem, a low molecular weight and low stereoregularity polyolefin copolymer is added, such as a low molecular weight and low stereoregularity polymer Propylene (low molecular weight and low modulus polypropylene) to improve poor fluidity while still maintaining excellent compression set. Referring to the examples listed in Table 7, it can be seen from the experimental data that the flowability of the dynamically crosslinked thermoplastic elastomer has been significantly improved after the addition of low molecular weight and low stereoregularity polypropylene.

Tenth embodiment (recipe number 12)

The preparation procedure is the same as that of the first embodiment of the present invention. When the second mixture is prepared in the second half, in the step of adding polypropylene, and ethylene-propylene-non-conjugated diene rubber , to a Wanbury Mixer, The weight of polypropylene is halved, and 20g of low molecular weight and low modulus polypropylene is mixed at the same time . As used herein, Idemitsu Kosan Co., Ltd.'s L-MODU ^™ , S400 product.

Eleventh Example (Formulation No. 13)

The preparation procedure is the same as that of the first embodiment of the present invention. When the second mixture is prepared in the second half, in the step of adding polypropylene, and ethylene-propylene-non-conjugated diene rubber , to a Wanbury Mixer, The weight of the polypropylene used is unchanged, and at the same time, 20 g of low molecular weight low stereoregularity polypropylene is added. As used herein, Idemitsu Kosan Co., Ltd. model S400 product (L-MODU ^™ , S400).

Referring to the data of the melting index in Table 7, the liquidity of the tenth embodiment and the eleventh embodiment is greatly improved.

However, the above embodiments are used to illustrate the characteristics of this creation, and its purpose is to enable those familiar with the technology to understand the contents of this creation and implement it accordingly, rather than limiting the patent scope of this creation, The equivalent modification or modification done by the spirit of disclosure should still be included in the scope of the patent application described below.

Claims (15)

A dynamically cross-linked thermoplastic elastomer, the composition of which includes: ethylene-propylene-non-conjugated diene rubber (EPDM) with a weight percentage of 55-70%; polypropylene (PP) with a weight percentage of 30-40%; The cross-linking agent is 1-7% by weight; and the additive is 0.6-3.6% by weight. The thermoplastic elastomer according to claim 1, wherein the polypropylene (PP) is selected from the group consisting of random copolymers of propylene, homopolymer of polypropylene (also known as homopolymer) , Or a combination thereof. The dynamic cross-linked thermoplastic elastomer according to claim 1, wherein when the dynamic cross-linked thermoplastic elastomer has flowability problems, the dynamic cross-linked thermoplastic elastomer component may further include a low molecular weight low stereoregular polypropylene ( low molecular weight and low modulus polypropylene). The dynamically cross-linked thermoplastic elastomer according to claim 1, wherein the additive is selected from ultraviolet stabilizers, light stabilizers, antioxidants, and combinations thereof. The dynamically cross-linked thermoplastic elastomer according to claim 1, wherein the cross-linking agent comprises peroxide and phenolic resin, and their weight percentages are 0.6-3.6% and 0.3-4.2%, respectively. The dynamically cross-linked thermoplastic elastomer according to claim 1, wherein the phenolic resin may be a phenolic resin with a methylol group, an alkylphenol-formaldehyde resin, or a halogen-substituted alkyl-substituted phenolic vulcanized resin through halogen The substituted phenol, alkyl-substituted phenol or unsubstituted phenol is prepared by condensation in an alkaline medium, the condensation of a bifunctional phenol diol is prepared, or the alkyl-substituted phenol vulcanized resin is prepared by halogenation. The dynamically crosslinked thermoplastic elastomer according to claim 6, wherein it is prepared by condensation of halogen-substituted phenol, alkyl-substituted phenol or unsubstituted phenol with aldehyde in an alkaline medium, and the alkyl-substituted phenol is preferred The latter is para-substituted, unsubstituted phenol and aldehyde, the aldehyde is preferably formaldehyde. The dynamically cross-linked thermoplastic elastomer according to claim 1, wherein the peroxide is selected from diacyl peroxide, tertiary alkyl peroxy acid ester, alkyl hydroperoxide, dialkyl peroxide , Dialkyl peroxyketal, and combinations thereof. A process for dynamically crosslinking thermoplastic elastomers, including steps: A: Polypropylene and ethylene-propylene-non-conjugated diene rubber are added to a 10,000 horsepower machine (Banbury Mixer). When the two materials are evenly melted, Add the first cross-linking agent-phenolic resin to form the first mixture; B: When the torque increases, stop the reaction, the material is discharged, and the roller is discharged; C: Add another batch of polypropylene, and ethylene-propylene-non-co- Conjugated diene rubber, added to a 10,000 horsepower machine (Banbury Mixer), after the two materials are evenly melted, add additives, the first mixture and the second crosslinking agent-peroxide, D: After the torque is increased to the maximum value , Continue mixing for another 3 minutes to form a second mixture, cut the material, and eject the tablets from the roller. The process for dynamically crosslinking a thermoplastic elastomer according to claim 9, wherein in step A, the weight of ethylene-propylene-non-conjugated diene rubber, polypropylene, and phenolic resin contained in the first mixture The percentages are 45-75%, 20-45%, and 5-20%. The process for dynamically crosslinking a thermoplastic elastomer according to claim 9, wherein in step C, the polypropylene, the ethylene-propylene-non-conjugated diene rubber, the additive, the first mixture, and the first The weight percent of the second crosslinking agent-peroxide is 23-39%, 45-65%, 0.6-3.6%, 6-19%, and 0.6-3.6%, respectively. The process for dynamically crosslinking a thermoplastic elastomer according to claim 9, wherein in step D, the polypropylene contained in the second mixture, the ethylene-propylene-non-conjugated diene rubber, the second The weight percentages of the cross-linking agent-peroxide, the additive, and the first cross-linking agent-phenolic resin are 30-40%, 55-70%, 0.6-3.6%, 0.6-3.6%, and 0.3-4.2 %. The process of dynamically crosslinking thermoplastic elastomer as described in claim 9, wherein the polypropylene (PP) is selected from the group consisting of random copolymers of propylene, polypropylene monopolymer (also known as homopolymer) (Homopolymer), low molecular weight low stereoregular polypropylene, or a combination thereof. The process for dynamically crosslinking thermoplastic elastomer as described in claim 9, wherein when the dynamic crosslinking thermoplastic elastomer has fluidity problems, in step C, a low molecular weight, low stereoregular polypropylene (low molecular) weight and low modulus polypropylene) to replace part of the other batch of polypropylene or directly add a certain weight of the low molecular weight and low stereoregularity polypropylene. The process for dynamically crosslinking a thermoplastic elastomer according to claim 9, wherein in step C, the additive is selected from ultraviolet stabilizers, light stabilizers, antioxidants, and combinations thereof.

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