TWI679237B - Dynamic crosslinked thermoplastic elastomer and its process - Google Patents

Abstract

The present invention relates to a dynamically crosslinked thermoplastic elastomer and its process. The main components of a dynamically crosslinked thermoplastic elastomer include ethylene-propylene-non-conjugated diene rubber (EPDM), polypropylene (PP), and two kinds of crosslinking agents, which are mixtures prepared through a dynamic crosslinking reaction. When preparing such a dynamically crosslinked thermoplastic elastomer, first the first crosslinking agent and some polypropylene, and ethylene-propylene-non-conjugated diene rubber are kneaded, and a preliminary crosslinking reaction is performed to form a first mixture, and then The second cross-linking agent and a new batch of polypropylene, ethylene-propylene-non-conjugated diene rubber and the first mixture containing the first cross-linking agent are mixed to produce a higher degree of cross-linking and mechanical properties. And a dynamically crosslinked thermoplastic elastomer with better processability. When the preparation has flowability problems, part of the polypropylene can be replaced with low molecular weight and low stereoregularity polypropylene (low molecular weight and low modulus polypropylene) to improve the dynamic crosslinked thermoplastic elastomer (TPV) with low flowability Problems, making its related processing and molding methods and applications wider.

Description

Dynamic crosslinked thermoplastic elastomer and its process

The invention relates to a dynamically crosslinked thermoplastic elastomer and a process for the same, and in particular, to a dynamically crosslinked thermoplastic elastomer obtained through a reaction of a double crosslinker and a process for the same. .

Thermoplastic elastomers (Thermplastic Elastomer, TPE), also known as thermoplastic rubber, is one of the most noticeable products in synthetic rubber raw materials in recent years. Thermoplastic elastomer TPE combines the elastic properties of rubber with the processing conditions of plastics. 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 during processing can be recycled and reused, which meets environmental protection requirements and can reduce costs. Thermoplastic elastomers also have high elongation, high rebound rate, 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 (TPU), thermoplastic polyolefin elastomers (TPO), dynamically crosslinked thermoplastic elastomers (thermoplastic vulcanizate, TPV), Polystyrenic block copolymers (TPS), polyetherester elastomers (thermoplastic copolyester, TPC), polyamidoamine-based elastomers (thermoplastic polyamides, TPA), have been dynamically crosslinked thermoplastic elastomers in recent years and are particularly affected by Attention, because it has the good elasticity of traditional elastomers and the recycling of thermoplastics It is an environmentally friendly polymer material, so it is widely used in industry, especially automotive and marine engines, and the demand is constantly growing. It is expected that it can replace the market of acrylic (ACM) rubber in the future.

In order to have the characteristics of both plastic and rubber, dynamic crosslinked thermoplastic elastomer materials (thermoplastic vulcanizate (TPV)) should contain both rubber (elastomer) and plastic (thermoplastic resin), and in the compound, the rubber composition percentage is usually Much higher than plastic. Rubber can be used with softening oil, plasticizer, etc. Cross-linking agents and some cross-linking aids are also indispensable. In addition, in order to reduce costs or improve some specific properties, some inorganic fillers are sometimes added.

When preparing dynamically crosslinked thermoplastic elastomers, the ingredients contained in the formula, such as rubber, plastic, and crosslinker, are mixed in advance and dynamically crosslinked in the extruder. The so-called dynamic crosslinking refers to the melt blending of rubber and plastic. At the same time, the rubber is dispersed in the plastic matrix and the rubber molecules are crosslinked to form a network structure, thereby improving the mechanical properties. The crosslinked rubber micro-regions mainly provide the elasticity of the blend, while the plastic matrix provides thermoplastic moldability. The so-called crosslinking / vulcanization of rubber refers to a chemical program in which rubber macromolecules are cross-linked with each other to generate a three-dimensional network structure. After this procedure, the chemical structure of the rubber is changed, and its performance is also improved. Therefore, TPV is a mixture of crosslinked rubber particles and plastic, the dispersed phase is rubber, and the continuous phase is crystalline plastic, which provides dimensional stability and thermoplasticity. Therefore, dynamically crosslinked thermoplastic elastomers have a relatively low compression set, and Performance is similar 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.

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

Dynamic crosslinked thermoplastic elastomer has good elasticity, resistance to compression deformation, corrosion resistance, aging resistance, weather resistance, wear resistance and oil resistance, easy dyeing, wide application temperature and hardness range, 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 composition of the selected rubber / plastic / crosslinking agent, dynamic crosslinked thermoplastic elastomer products with different properties can be obtained. Other factors that affect product properties are technical conditions and mixing equipment. Crosslinking agents can determine the degree of dynamic crosslinking of the product and affect various physical and chemical characteristics of the thermoplastic elastomer. Crosslinking agents (also known as vulcanizing agents) can be divided into sulfur vulcanization systems and Non-sulfur vulcanization systems, including peroxides, phenolic resins, amines, metal oxides, and radiation.

Sulfur vulcanization system, although the cost is low, but the vulcanization speed is slow, the time is long, the product has an odor, and the high temperature crosslinking is unstable.

Peroxide can make the cross-linking reaction proceed at a lower temperature. The TPV product obtained through oxide vulcanization has superior heat resistance and lower compression. It has superior heat resistance and lower compression deformation. The color is lighter and easier to color. Dry, but the peroxide will cause the degradation of plastic / resin molecules, and the product has poor physical and mechanical properties (such as low tensile strength, poor tear strength and poor wear resistance).

The phenolic resin cross-linking agent is used, so it has good mechanical strength, good melt strength and weather resistance, high temperature resistance, oil resistance and chemical corrosion resistance. The disadvantage is that the speed is slow, the vulcanization temperature is generally high, chloride is required as an activator, the vulcanization process is complicated, there are slight color differences between different product batches, and there are odor problems. In addition, the material has strong hygroscopicity and needs to be dried before processing. .

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

In order to meet the above requirements and overcome the shortcomings of conventional dynamic crosslinked thermoplastic elastomers, it is an object of the present invention to provide a dynamically crosslinked thermoplastic elastomer (TPV) prepared by using a dual crosslinking agent and a process for the same. 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 low molecular weight and low stereoregularity polypropylene (low molecular weight and low modulus polypropylene). When fluidity problems occur in the body, adding such polypropylene can obviously improve and solve the fluidity problems.

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

To achieve the above objective, the present invention provides a process for dynamically crosslinking a 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-copolymer The yoke diene rubber is added to a Banbury Mixer. After the two materials are evenly melted, a first cross-linking agent, a phenolic resin, is added for a preliminary cross-linking reaction to form a first mixture. When the torque increases, first temporarily The reaction is stopped, so the first mixture still has cross-linking reactivity, and the material is discharged and rolled out by a roller.

Then add another part of polypropylene and another part of ethylene-propylene-non-conjugated diene rubber to a Banbury Mixer. After the two materials are evenly melted, add ultraviolet stabilizer, light stabilizer, Additives such as oxidants, the first mixture, and the second cross-linking agent-peroxide; after 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 cross-linking Thermoplastic elastomer, the roller will be ejected from the blank.

When the prepared dynamically crosslinked thermoplastic elastomer (TPV) has a 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 may be added directly, that is, the total amount of polypropylene is increased. This low molecular weight polypropylene has the characteristics of low melting point, high fluidity and softness, 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 dynamic 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 and molding methods and applications wider. .

The advantages and technical features of the present invention are as follows: in preparing the dynamically crosslinked thermoplastic elastomer (TPV), a dual crosslinking agent is used, and at the same time, in the process of dynamically crosslinking the thermoplastic elastomer, the first crosslinking agent and part of the polymer are firstly polymerized. Propylene and ethylene-propylene-non-conjugated diene rubber are kneaded, and a preliminary cross-linking reaction is performed to form a first mixture. When the torque is increased, the reaction is temporarily stopped first, and the sheet is 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 Minutes, when the reaction reaches equilibrium, a dynamically crosslinked thermoplastic elastomer with a higher degree of crosslinking is produced.

FIG. 1 is a graph showing changes in melt temperature and torque with time during the preparation process according to an embodiment of the present invention.

Dynamic crosslinked thermoplastic elastomer system is a new type of polymer material between rubber (elastomer) and plastic (resin). It has the flexibility of thermoplastic and rubber of plastic 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. The elastic rubber is completely and uniformly dispersed in the thermoplastic, the thermoplastic is a continuous phase, and the elastic rubber forms a dispersed phase. The size of the elastic rubber particles is from 0.1 micrometer to about several micrometers, and the cross-linking density is greater than 7 × 10 ^-5 mol / ml, and other additives are also contained inside the particles. These large numbers of finely crosslinked rubber particles are dispersed in the plastic in a dispersed phase, and there should be no chemical bonding between the particles. Therefore, the dynamically crosslinked thermoplastic elastomer has high elasticity, excellent tensile properties and good compression set. The plastic particles that surround the elastic rubber particles form a continuous phase, providing excellent thermal fluidity and repetitive processability of dynamically crosslinked thermoplastic elastomers. Therefore, the dynamically crosslinked thermoplastic elastomer is pressure-resistant and stretchable like rubber, and is processed like plastic, and has stable physical properties.

The dynamically crosslinked thermoplastic elastomer (TPV) according to the present invention is a mixture including a crosslinkable (vulcanizable) elastic rubber, that is, an oil-extended or non-oil-extended ethylene-propylene-non-conjugated diene rubber. It is dispersed in a thermoplastic polyolefin such as polypropylene. The polypropylene may be a random copolymer and / or a single polymer. Peroxide and phenolic resin are used as a crosslinking agent (vulcanizing agent) to make ethylene-propylene. -The non-conjugated diene rubber undergoes a specific process to produce a dynamic cross-linking reaction to form a dynamically cross-linked thermoplastic elastomer. In addition, when the dynamically crosslinked thermoplastic elastomer product has fluidity problems, low molecular weight polyolefin copolymers, such as low molecular weight and low stereoregularity polypropylene (low molecular weight and low modulus polypropylene), can be added as modifiers. To improve the fluidity and surface smoothness of dynamically crosslinked thermoplastic elastomers.

Ethylene-propylene-non-conjugated diene rubber (EPDM), also known as ethylene-propylene diene rubber, is a terpolymer 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 is a semi-crystalline polymer with high crystallinity, which makes it excellent in 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. Polypropylene random polymer has low crystallinity, which makes it good in transparency and can improve product appearance. Makes the product softer. Compared with single polymers, random copolymers have lower melting points and crystallization temperatures, making them easier to process.

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

Then proceed to step C: add another batch of propylene and ethylene-propylene-non-conjugated diene rubber to a Banbury Mixer. After the two materials are evenly melted, add ultraviolet stabilizer, light Stabilizers, antioxidants and other additives, the first mixture and the second cross-linking agent-peroxide , continue to knead ; Step D: After the torque increases to the maximum, continue to mix for another 3 minutes, so that the reaction reaches equilibrium, forming a The second mixture (see Table 2), that is, the dynamically crosslinked thermoplastic elastomer (TPV), was cut out to roll out the tablet.

Phenolic vulcanizate is a kind of surfactant. It undergoes cross-linking reaction with double bonds in ethylene-propylene-non-conjugated diene rubber through ion polymerization. The phenolic vulcanized resin refers to a concentrated masterbatch of a phenolic vulcanized resin. In the process of preparing dynamically crosslinked thermoplastic elastomers, the plastic materials used sometimes have fluidity problems, that is, when heated, the plastic molecules will not flow easily, making it difficult to melt. When the phenolic vulcanized resin reacts directly with ethylene-propylene-non-conjugated diene rubber, the dispersibility of ethylene-propylene-non-conjugated diene rubber can be improved, and the crosslinking reaction process of the dynamically crosslinked thermoplastic elastomer is stable. , 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 vulcanization resin. The halogen-substituted phenol, the alkyl-substituted phenol (preferably para-substituted) ) Or an unsubstituted phenol and an aldehyde (preferably formaldehyde) are prepared by condensation in an alkaline medium, or a bifunctional phenol diol is prepared by condensation.

As for peroxides, cross-linking reactions occur between polymers by free radicals. During the reaction, hydrogen peroxide or generated free radicals in peroxides will interact with saturated bonds and methylene bonds (-CH ₂ ). It reacts with a methyl bond (-CH ₃ ) to perform a free radical grafting and bridging reaction. A dynamically vulcanized olefin-based thermoplastic elastomer (thermoplastic vulcanizate (TPV)) using an organic peroxide as a cross-linking agent is formed with a -CC-bond after cross-linking, which is more than -C-Sx formed with a conventional sulfur-based cross-linking agent. -C-bond is more stable, so it shows better heat resistance and aging resistance. Peroxides suitable for industrial production are: difluorenyl peroxide, tertiary alkyl peroxyester, alkyl hydroperoxide, dialkyl peroxide, dialkyl peroxyketal. Commonly used ones include dicumyl peroxide (DCP), benzophenazine 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) and the like.

The components of the dynamically crosslinked thermoplastic elastomer (TPV) according to the present invention may further include low molecular weight and low stereoregular polypropylene (low molecular weight and low modulus polypropylene), which has the characteristics of low melting point, high fluidity, softness, and the like. , Can improve the physical properties and processing properties of TPV. For example, at the processing temperature, the fluidity of the dynamically crosslinked thermoplastic elastomer (TPV) is low, and it does not affect the compression set of the product, or increase the toughness of the final product, making the related processing and molding methods and applications more extensive.

First embodiment:

See Table 3 for Formula Number 3. Take 12 g of polypropylene (random copolymer, monopolymer, or mixture thereof), and 20 g of ethylene-propylene-non-conjugated diene rubber (EPDM), in this example: EPT-3045 manufactured by Mitsui Chemicals, Inc. of Japan was uniformly melted using a Banbury Mixer , and 4 g of a first cross-linking agent, a phenol resin (Tackirol 201, manufactured by Taoka Chemical Industries) was added. A preliminary cross-linking reaction is performed to form a first mixture, and its composition ratio range is shown in Table 1.

Then take 40g of polypropylene (random copolymer, monopolymer or mixture thereof) and 100g of ethylene-propylene-non-conjugated diene rubber , put them into a Banbury Mixer, and make them melt uniformly. , 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, the composition ratio range, see Table 2: As the torque increases, the mixing is continued for 3 minutes, and the reaction reaches equilibrium to obtain the dynamically crosslinked thermoplastic elastomer of the present invention. For the range of composition ratios of the dynamically crosslinked thermoplastic elastomer of the present invention, please refer to Table 3. 20g of the first mixture is divided into 12g of ethylene-propylene-non-conjugated diene rubber, 6g of polypropylene and 2g of phenolic vulcanizate. (Proportions are 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 cross-linking agent is 1-7% by weight, and it contains phenolic resin and peroxide. The weight percentages are 0.3-4.2% and 0.6-3.6%, and the weight percentage of additives is 0.6- 3.6%.

Table 4: Characteristics of each dynamically crosslinked thermoplastic elastomer (TPV) made with similar formulations but different crosslinkers

Comparative Example 1 (Recipe No. 1)

The preparation procedure is the same as that of the first embodiment of the present invention, but in step C: when adding ultraviolet stabilizer, light stabilizer, antioxidant and other additives, the first mixture and the second crosslinking agent, the second crosslinking agent is not added at all. As an oxide, 5 g of phenolic resin is added; therefore, in this embodiment, only phenolic resin is used as the cross-linking agent.

Comparative Example 2 (Recipe No. 2)

The preparation procedure is the same as that of the first embodiment of the present invention, but the steps A and B of preparing the first mixture in the first half are omitted, and the step C of the second half is adding additives such as a UV stabilizer, a light stabilizer, an antioxidant, the first mixture, and When the cross-linking agent is used, 2.0 g of peroxide is added as the cross-linking agent; that is, only peroxide is used as the cross-linking agent in this embodiment.

First embodiment (recipe number 3)

Formula No. 3 is the first embodiment of the present invention, which includes steps A and B for preparing the first mixture in the first half, using phenolic resin as a crosslinking agent, and steps C and D for preparing the second mixture in the second half. Peroxide is used as the cross-linking agent; that is, phenolic resin and peroxide are used simultaneously, and the double-cross-linking agent is used.

See Table 4. Dynamic crosslinked thermoplastic elastomers (TPV) produced using different crosslinking agents, such as phenolic resins, peroxides, and mixtures thereof. According to the test data, it is known that when phenolic resin is used alone as a cross-linking agent, its 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, its physical properties It is the worst; and by combining two cross-linking agents of phenolic resin and peroxide, the physical properties of the dynamically cross-linked thermoplastic elastomer obtained are not far from those of phenolic resin, but the degree of cross-linking is greatly improved 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 formula / composition is changed from EPT-3045 of Mitsui Chemicals of Japan to Dow of China NORDEL ^™ EPDM IP 4640 manufactured by the 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) was changed from EPT-3045 of Mitsui Chemicals Co., Ltd. of Japan to KEP650 manufactured by Kumho Polychem Co., Ltd. of Korea.

The composition of the dynamically crosslinked thermoplastic elastomer (TPV) will affect the physical properties of the product. Therefore, different manufacturers-Japan's Mitsui, China's Dow, and Korea's Kumho Chemical Company-use ethylene-propylene-non-co-equivalent non-oil exhibition equivalent Mooney viscosity (ML (1 + 4) 100 ℃) The conjugated diene rubber (EPDM) is made into a dynamically crosslinked thermoplastic elastomer. For comparison of its physical properties, see Table 5. The physical properties of dynamically crosslinked thermoplastic elastomers are better in Kumho, Korea and Mitsui in Japan, while the melt index is higher in Mitsui, Japan. Melt flow index (MI), also known as melt flow rate (MFR), is a physical parameter that measures the quality of a material, usually a rubber or plastic material, under certain temperature and pressure conditions. The larger the MI value, the better the fluidity, and the worse it is, 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 in accordance with the test method specified in ASTM D412.

In order to develop a dynamic crosslinked thermoplastic elastomer (TPV) suitable for injection molding, the ratio of the first mixture containing phenolic resin and the 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 that of the first embodiment of the present invention. The weight of the first mixture used in Formulation No. 3 is unchanged, but the peroxide is changed to 1 g.

Fifth embodiment (recipe number 7)

The preparation procedure is the same as that of 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 that of the first embodiment of the present invention, and the first mixture used in Formulation No. 3 The weight of the compound was unchanged, but the peroxide was 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 30 g, and the peroxide is changed to 3 g.

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 crosslinked thermoplastic elastomer (TPV) of Formula 8. cannot be applied to injection molding, in order to solve this problem, a low molecular weight and low stereoregularity polyolefin copolymer such as a low molecular weight and low stereoregularity polymer is added. 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 known from the experimental data that after adding low molecular weight and low stereoregularity polypropylene, the fluidity of the dynamically crosslinked thermoplastic elastomer is significantly improved.

Tenth embodiment (recipe number 12)

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

Eleventh embodiment (recipe number 13)

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

Referring to the data of the melt index in Table 7, the tenth embodiment and the eleventh embodiment both greatly improved the fluidity.

However, the above embodiments are used to explain the characteristics of this creation, and the purpose is to enable those skilled in the art to understand and implement the content of this creation, not to limit the patent scope of this creation. Therefore, all other equivalent modifications or modifications made without departing from the spirit disclosed in this creation should still be included in the scope of patent application described below.

Claims (5)

A process for dynamically cross-linking a thermoplastic elastomer includes steps: A: adding polypropylene and ethylene-propylene-non-conjugated diene rubber to a 10,000 horsepower machine (Banbury Mixer). After the two materials are uniformly melted, Add the first cross-linking agent-phenolic resin to form the first mixture; B: Stop the reaction when the torque increases, cut the material, and roll out the tablet; C: Combine another batch of polypropylene with ethylene-propylene-non-co- Add conjugated diene rubber to a 10,000 horsepower mixer (Banbury Mixer). After the two materials are uniformly melted, add the additive, the first mixture, and the second cross-linking agent, peroxide. D: After the torque is increased to the maximum , Continue to mix for another 3 minutes to form a second mixture, cut out, and take out the tablets from the roller machine. The process for dynamically crosslinking a thermoplastic elastomer according to claim 1, wherein in step A, the weight of the 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 1, wherein in step C, the polypropylene, the ethylene-propylene-non-conjugated diene rubber, the additive, the first mixture, and the first The weight percentages of the dicrosslinking agent-peroxide are 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 1, wherein in step D, the polypropylene contained in the second mixture, the ethylene-propylene-non-conjugated diene rubber, and 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, respectively. %. The process for dynamically crosslinking a thermoplastic elastomer according to claim 1, wherein in step C, the additive is selected from the group consisting of a UV stabilizer, a light stabilizer, an antioxidant, and a combination thereof.