WO2021042692A1

WO2021042692A1 - Method for preparing pebax into tpv foam material, and tpv foam material

Info

Publication number: WO2021042692A1
Application number: PCT/CN2020/078152
Authority: WO
Inventors: 张小海; 张振秀; 陈建亚
Original assignee: 福建兴迅新材料科技有限公司
Priority date: 2019-09-04
Filing date: 2020-04-02
Publication date: 2021-03-11
Also published as: CN111040420A

Abstract

Disclosed in the present invention is a method for preparing PEBAX into a TPV foam material, and a TPV foam material, said method comprising the following steps: ① pre-vulcanization of PEBAX/MPU or PEBAX/EPDM-MAH: mixing a vulcanizing agent and an alkaline filler evenly to prepare a mixture, and plasticizing MPU or EPDM-MAH into softened MPU or EPDM-MAH; kneading the mixture and the plasticized MPU or EPDM-MAH until the components are evenly mixed to obtain a kneaded material; blending the kneaded material and PEBAX to obtain a TPV material, and performing a vulcanization operation on the TPV material to obtain a pre-vulcanized TPV material; ② supercritical foaming: after cooling to room temperature, placing the pre-vulcanized TPV material in a high-pressure reaction vessel and performing supercritical foaming to obtain a TPV foam material. The TPV foam material obtained in the present invention combines excellent performance of two types of material, is lightweight and flexible, and has good resilience. Tensile strength, tearing strength, peel strength and adhesiveness are all greatly improved relative to PEBAX, and the material has good formability, excellent energy absorption and shock absorbing performance, and is more suited for fields such as the manufacturing of shock absorbing components or shock absorbing packaging material.

Description

A method for preparing TPV foam material by PEBAX and TPV foam material

技术领域Technical field

Technical field

The invention relates to the field of TPV foam materials, and specifically relates to PEBAX/MPUTPV and PEBAX/EPDM-MAHTPY foam materials and preparation methods thereof and TPY foam materials.

Background technique

At present, in order to increase the comfort of people’s lives, various shock-absorbing materials have been widely used. For example, in the field of shoe midsole materials, foamed EVA, TPU and PU materials have been widely used, and various materials are based on their performance. Features occupy a market share of its own in the market, and people are also continuously developing new shock-absorbing elastic materials.

According to research findings, PEBAX is a block copolymer formed by polyamide and polyether. It is a thermoplastic elastomer material. The foamed product is light and soft, has excellent resilience, low temperature flexibility and resistance. Compressed, environmentally friendly, and recyclable, it is currently one of the most popular elastomers, but its price is relatively high, and there are some disadvantages in tensile strength, tear strength, peel strength and adhesion properties. MPU is also a polyether elastomer and has good compatibility with PEBAX. The polyimide bond in PEBAX is also compatible with the maleic anhydride in EPDM-MAH. From the perspective of environmental protection, supercritical foaming is currently the most environmentally friendly foaming method. From the foaming agent, foaming conditions to the foamed product, it is non-toxic and harmless.

Therefore, how to improve the disadvantages of PEBAX elastomers and reduce the cost of foam materials without affecting the advantageous properties of PEBAX elastomers is a problem that needs to be solved urgently in the market.

Based on the above-mentioned needs and current situation, the applicant conducted in-depth research, and this case emerged.

Summary of the invention

The main purpose of the present invention is to provide a method for preparing TPV foam material from PEBAX, which adopts PEBAX/MPU or PEBAX/EPDM-MAH for physical foaming, which has the performance advantages of both materials, and makes the material resilient and stretchable. Strength, tearing strength, peeling tearing strength, bonding strength, etc. have been improved to a certain extent, and it has good processing and moldability, and appropriately reduces the cost required to prepare pure PEBAX foam materials.

In order to achieve the above-mentioned purpose, the solution of the present invention is: a method for preparing TPV foam material from PEBAX, which includes the following steps: ① Pre-vulcanization of PEBAX/MPU or PEBAX/EPDM-MAH: mix the vulcanizing agent with the alkaline filler. Make a mixture, masticate the MPU or EPDM-MAH to soften; knead the mixture and the plasticized MPU or EPDM-MAH until the components are evenly mixed to obtain a mixture. The mixture accounts for 3%-10% of the mass of the plasticized MPU or EPDM-MAH; blend the mixture with PEBAX to obtain the TPV material, and subject the TPV material to the vulcanization operation to obtain the TPV presulfide; ②Supercritical foaming: The TPV presulfide cooled to room temperature is placed in an autoclave for supercritical foaming to obtain a TPV foam material.

Further, the mass ratio of the mixture to PEBAX is 3:7 to 5:5, the blending temperature is 130°C-150°C, the blending time is 4min-10min, and the vulcanization temperature is 130°C-150° C, the curing time is 15min-30min.

Further, in step ②, CO2 is introduced into the high-pressure reactor and the temperature is raised and pressurized to convert CO2 into supercritical CO2. When the supercritical CO2 is saturated in the TPV material, the pressure reduction method is used to quickly reduce the pressure in the high-pressure reactor. The pressure is reduced to normal pressure, and TPV foam material is obtained.

Further, the basic filler is nano silica, the vulcanizing agent is dicumyl peroxide, and the mass ratio of the vulcanizing agent to the basic filler is 1:2.

Further, the MPU is a polyether mixed polyurethane, EPDM-MAH is a maleic anhydride grafted EPDM rubber, and the PEBAX is a thermoplastic polyamide-polyether block copolymer.

Furthermore, the setting temperature of the above-mentioned mastication and kneading are both 110°C -120°C.

The present invention also provides a TPV foam material prepared by the above method.

After adopting the above structure, the present invention relates to a method for preparing TPV foam from PEBAX, which has at least the following beneficial effects: 1. The present invention separates the cross-linking reaction process from the supercritical foaming process, and no chemical reaction proceeds during foaming. It avoids the cross-linking reaction from interfering with the cell nucleation and growth process, and there is no reaction heat generated during the foaming process, so the foaming process is easier to control, and the cell distribution in the foamed product is more uniform. Therefore, the TPV foam material prepared by the method of the present invention has better resilience and impact resistance.

2. From the aspect of processing technology, the addition of vulcanizing agent and alkaline filler makes EPDM-MAH internally form a three-dimensional cross-linked structure, and also makes the cross-linking strength of MPU far greater than the physical cross-linking of the crystal structure formed by the hard segment itself. The joint strength provides a positive influence for the later foaming; from the material aspect, PEBAX/MPU TPV and PEBAX/EPDM-MAH TPV materials are a new type of material with the excellent properties of both materials. The foamed porous The material has the characteristics of light weight, good abrasion resistance, excellent impact absorption performance, etc., and improves the tensile and tearing and adhesion properties of the material, and can be used as shock-proof cushioning materials, shoe sole materials, etc.

3. The TPV foam material prepared by the method of the present invention is obtained from MPU or EPDM-MAH through pre-vulcanization, PEBAX and MPU or EPDM-MAH blending and supercritical foaming. It is a TPV porous material, MPU or Appropriate chemical cross-linking points in EPDM-MAH can more effectively prevent the viscous flow between the molecular chains of TPV, provide a certain degree of stiffness and air tightness, and the distribution of cells in the material is uniform.

4. The mixture accounts for 3%-10% of the mass of the plasticized MPU or EPDM-MAH, if less than 3%, for the blended TPV, the crosslinking effect and foaming effect of the mixture The nucleation effect is not significant, and after using supercritical carbon dioxide foaming, the phenomenon of foam shrinkage and cell collapse is likely to occur; and when the content is greater than 10%, the content of the mixture is too much, the crosslinking point and the filler are too much, and the chain The movement of segments and molecular chains is affected, and the resistance to dissolution and diffusion of gas increases, which inhibits foaming of the material and affects the performance of the material; therefore, within the range of 3%-10%, the mixture will crosslink and form nuclei for TPV. , Foaming, performance improvement, processing and molding have a positive impact.

Compared with the prior art, the TPV foam material obtained by the present invention is a new type of foam material that combines the excellent properties of the two materials, and has good processing and moldability, and has better energy absorption and cushioning and shock absorption properties. It is more suitable for the production of shock-absorbing and cushioning parts or shock-absorbing and cushioning packaging materials.

Description of the drawings

Figure 1 shows the density change curves of four embodiments of the present invention after foaming.

Fig. 2 is the variation curve of resilience and Shore C hardness of four embodiments of the present invention.

Fig. 3 is the change curve of the compression permanent deformation of the four embodiments of the present invention.

Fig. 4 is the change curve of tensile strength and elongation of four embodiments of the present invention.

Fig. 5 is the change curve of the tear strength and the peel tear strength of the four embodiments of the present invention.

detailed description

In order to further explain the technical solution of the present invention, the present invention will be described in detail below through specific embodiments.

Example 1 In this example, the preparation method of the PEBAX/MPU made of TPV foam material is as follows: (1) PEBAX/MPU type TPY pre-vulcanization combines 0.6 g of vulcanizing agent dicumyl peroxide and alkaline filler nano-two Mix 1.2 g of silicon oxide to obtain a mixture. Add 30 g of MPU into the internal mixer and plasticize at 120°C for 1 min to soften the MPU. Then add the mixture to the internal mixer and mix at 120°C for 5 minutes. Mix the above three materials uniformly to obtain a mixture, and then add 70g of PEBAX and mix for 6 minutes at 13°C until uniform, and pre-vulcanize by a flat vulcanizer. The specific operation is: vulcanize the mixture at 140°C for 15 minutes , Exhaust three times to obtain a sheet-like presulfide with a thickness of 4%.

(2) Supercritical foaming. After step (1), the obtained presulfide is cooled to room temperature and placed in an autoclave. Carbon dioxide is introduced and the temperature in the autoclave is controlled to 10 °C and the pressure is 14 MPa to convert carbon dioxide into In the supercritical state, and maintaining the pressure at the aforementioned temperature for 2 hours, the supercritical carbon dioxide reaches saturation in the presulfide, and then rapidly reduces the pressure to reduce the pressure in the autoclave to normal pressure to obtain PEBAX/MPU-type TPV foam materials.

The PEBAX/MPUTPY foam material prepared in this example was brittle fractured with liquid nitrogen, and its section was observed by scanning electron microscopy (SEM). The observation showed that the PEBAX/MPUTPY foam material prepared in this example had a uniform distribution of cells.

Example 2 In this example, the preparation method of TPV foam made of PEBAX/MPU is as follows: (1) PEBAX/MPU type TPY pre-vulcanized, vulcanizing agent dicumyl peroxide lg and alkaline filler nano silica 2g Mix uniformly to obtain the mixture, add 50g of MPU into the internal mixer at 120°C for lmin to soften the MPU, then add the mixture into the internal mixer, and mix for 5 min at 12°C to mix the above three materials Mix uniformly to obtain the mixture, and then add 50g of PEBAX and mix for 6 min to uniformity at 13 °C, and pre-vulcanize by a flat vulcanizer. The specific operation is: vulcanize the mixture at 14 °C for 15 minutes, exhaust three times, A sheet-like presulfide with a thickness of 4 legs is obtained.

(2) Supercritical foaming After the pre-stone filling obtained in step (1) is cooled to room temperature, it is placed in an autoclave, and carbon dioxide is introduced and the temperature in the autoclave is controlled to 110°C and the pressure to be 14MPa. The carbon dioxide is transformed into a supercritical state, and the pressure is maintained at the aforementioned temperature for 2 hours, the supercritical carbon dioxide is saturated in the presulfide, and then the pressure in the high-pressure reactor is reduced quickly to normal pressure, and the PEBAX/MPU-type TPV is obtained.泡材料。 Bubble material.

Example 3

In this embodiment, the preparation method of PEBAX/EPDM-MAH made of TPV foam material is as follows: (1) PEBAX/EPDM-MAH type TPY pre-vulcanization of vulcanizing agent 0.6g dicumyl peroxide and alkaline filler nano dioxide Mix 1.2g of silicon to obtain a mixture. Add 30g of EPDM-MAH to the internal mixer at 110°C for lmin to soften the EPDM-MAH, and then add the mixture to the internal mixer at 110°C. Mix the above three materials for 5 minutes to obtain a mixture, then add 70g of PEBAX and mix at 130°C for 6 minutes to uniformity, and pre-vulcanize by a plate vulcanizer. The specific operation is: Vulcanize at 140°C for 15 minutes and vent three times to obtain a sheet-like presulfide with a thickness of m.

(2) Supercritical foaming After the pre-stone filling obtained in step (1) is cooled to room temperature, it is placed in an autoclave, and carbon dioxide is introduced and the temperature in the autoclave is controlled to 95°C and pressure to 14 MPa. The carbon dioxide is transformed into a supercritical state, and the pressure is maintained at the aforementioned temperature for 2 hours. The supercritical carbon dioxide is saturated in the presulfide, and then the pressure in the autoclave is reduced quickly to normal pressure, and PEBAX/EPDM-MAH is obtained. TPV-like foam material.

Example 4 In this example, the preparation method of PEBAX/EPDM-MAH made of TPV foam material is as follows: (1) PEBAX/EPDM-MAH type TPY pre-vulcanization of vulcanizing agent dicumyl peroxide lg and alkaline filler nano 2g of silica was mixed uniformly to obtain a mixture, 50g of EPDM-MAH was added to the internal mixer at 110°C for lmin to soften the EPDM-MAH, and then the mixture was added to the internal mixer at 11°C Mix the above three materials for 5 minutes to obtain a mixture, then add 50g of PEBAX and mix for 6 minutes at 130°C until uniform, and pre-vulcanize by a plate vulcanizer. The specific operation is: (TC vulcanized for 15 minutes and exhausted three times to obtain a sheet-like presulfide with a thickness of 4 awake.

⑵Supercritical foaming to be step ⑴After the obtained presulfide is cooled to room temperature, put it in an autoclave, pass carbon dioxide and control the temperature in the autoclave to 50XJ and pressure to 14MPa to transform the carbon dioxide into a supercritical state. And after maintaining the pressure at the aforementioned temperature for 2 hours, the supercritical carbon dioxide is saturated in the presulfide, and then the pressure in the autoclave is quickly reduced to normal pressure, thereby obtaining the PEBAX/EPDM-MAH type TPV foaming material.

Performance analysis The foamed products of the four embodiments described above are respectively denoted as TPV1, TPV2, TPV3, and TPV4.

Pure PEBAX foam material is referred to as PEBAX. We compare, analyze and discuss the above four TPV products in terms of density change rate, compression set, resilience, hardness, tensile strength, tear strength, and peel tear strength.

The density change curve after foaming is shown in Figure 1.

When supercritical carbon dioxide is used to foam materials such as elastomers and rubber, foam shrinkage and cell collapse are prone to occur, which increases the density of the foamed material, even loses its elasticity, reduces its performance, and greatly reduces its application value. Using the four TPVs produced in this case, the density tends to be stable for a period of time after supercritical carbon dioxide foaming, and can be controlled between 1.2-0.165g/cm3. Compared with pure PEBAX foam, TPV1 and TPY3 have lighter density. . Comparing TPV1 and 2, with the increase of MPU components, the initial and final density of TPY2 after foaming is larger than that of TPY1. This is due to the increase in the mixture of DCP and nano-silica, which is easy to form a cross-linked network and physical Cross-linking points, on the one hand, a certain degree of three-dimensional network structure serves as a skeleton to support the generation of cells during the foaming process. On the other hand, excessive three-dimensional network structure will increase the dryness of the foaming material and the movement of molecular chains and segments. Affected, and the heterogeneous nucleation is weakened, which increases the resistance in the process of gas nucleation and growth, inhibits the foaming of the material, and causes the density of TPY2 to increase. Comparing TPV3 with 4, the difference in polarity between EPDM rubber and Pebax elastomer results in poor compatibility. Grafting MAH onto EPDM improves the compatibility between the two. With the EPDM-MAH group The increase in the fraction increases the final density of the material. This may be because when the EPDM-MAH rubber component increases, the vulcanization of DCP causes a large number of chemical cross-linking points in the TPV, and the gas dissolution and diffusion rate decreases, but The stiffness and shrinkage stability of the material are improved; while nano-silica exists between the polymer molecular chains, too much addition is prone to agglomeration, uneven dispersion, and heterogeneous nucleation between the polymer matrix and the silica filler The effect is weakened and the free volume of the polymer molecular chain is squeezed. When foaming, the cells need to overcome greater resistance during nucleation and growth. The macroscopic performance is that under the same process conditions, TPY4 has the highest density. Comparing TPV1,2 and TPY3,4 comprehensively, the former is lighter, and the density can reach 0.123g/cm3; while the latter also breaks through the shortcomings of poor compatibility between PEBAX and EPDM and combines the advantages of both.

The resilience and Shore C hardness are shown in Figure 2.

The resilience of the TPV foam materials in the above four cases is 65% and above, and the Shore C hardness is 40-50. These TPVs are comfortable and soft, have good elasticity, and have an ideal shock absorption effect. They can be used in shoe midsole materials and cushioning materials. The resilience of elastomer and rubber foam materials has a great relationship with their own cross-linked structure, viscoelasticity and density. Compared with pure PEBAX foam materials, although the resilience of these TPVs has decreased slightly, it is still above 65%.

We compare TPV1, 2 and TPV3 and 4 respectively. TPV1 and TPY3 with more PEBAX components have better resilience, low hardness and softness. This is because a proper cross-linked network structure is conducive to the formation of a good cell structure, the material has a larger storage modulus, a reduced loss modulus, and a better resilience performance; too much three-dimensional cross-linked network structure will make the network chain molecular weight Although the decline restricts the slip of the molecular chain, it also hinders the movement of the chain segment, which increases the internal friction during the movement of the chain segment, increases the dynamic mechanical loss, and decreases the resilience performance.

Compression permanent deformation, as shown in Figure 3.

The tensile strength and elongation are shown in Figure 4.

The tear strength and peel tear strength are shown in Figure 5.

The compression permanent deformation rate of the above four cases of TPV has been improved to a certain extent for pure PEBAX foam (the compression change of PEBAX foam is generally about 40%). The tensile strength, elongation at break, tear strength and peel tear strength have been greatly improved and improved.

The construction of the cross-linked structure in TPY connects the molecular chains into a network structure, which not only increases the molecular weight, but also enhances the interaction between the molecular chains, inhibits the relative slippage of the molecular chains, and makes the material structure more stable. When the material is subjected to external force , The tensile performance, elasticity, and creep resistance are greatly improved.

Furthermore, due to the introduction of MPU and EPDM-MAH components, the adhesion performance of TPV will be better than that of PEBAX, which is conducive to the molding and processing of materials.

Claims

1. A method for preparing TPV foam material from PEBAX, characterized in that it comprises the following steps:

①Pre-vulcanization of PEBAX/MPU or PEBAX/EPDM-MAH:

Mix vulcanizing agent and alkaline filler uniformly to make a mixture, and masticate MPU or EPDM-MAH to soften MPU or EPDM-MAH;

Mix the mixture with the plasticized MPU or EPDM-MAH until the components are uniformly mixed to obtain a mixture, and the mixture accounts for 3-10% of the mass of the plasticized MPU or EPDM-MAH;

Blend the mixture with PEBAX to obtain a TPV material, and subject the TPV material to a vulcanization operation to obtain a TPV presulfide;

② Supercritical foaming: The TPV presulfide cooled to room temperature is placed in a high-pressure reactor for supercritical foaming to obtain TPV foam.

2. A method for preparing TPV foam from PEBAX according to claim 1, wherein the mass ratio of the mixture to PEBAX is 3:7 to 5:5, and the blending temperature is 130°C-150 ℃, the blending time is 4min-10min, the vulcanization temperature is 130℃-150℃, and the vulcanization time is 15min-30min.

3. A method for preparing TPV foam from PEBAX according to claim 1, wherein in step ②, CO _{2 is introduced} into the autoclave and the temperature is raised and pressurized to convert CO ₂ into supercritical CO _2. When the supercritical CO ₂ is saturated in the TPV material, the pressure in the autoclave is reduced to normal pressure by the rapid depressurization method to obtain the TPV foam material.

4. The method for preparing TPV foam from PEBAX according to claim 1, wherein the basic filler is nano silica, the vulcanizing agent is dicumyl peroxide, and the vulcanizing agent is dicumyl peroxide. The mass ratio with alkaline filler is 1:2.

5. The method for preparing TPV foam from PEBAX according to claim 1, wherein the MPU is a polyether mixed polyurethane, and EPDM-MAH is a maleic anhydride grafted EPDM rubber , The PEBAX is a thermoplastic polyamide-polyether block copolymer.

The method for preparing TPV foam from PEBAX according to claim 1, characterized in that the temperature of the mastication and kneading are both 110°C-120°C.

7. A TPV foam material, characterized in that it is prepared by a method according to any one of claims 1-6.