Polyolefin elastomer foaming coating material and preparation method thereof

Abstract

The invention relates to the technical field of foaming materials, and particularly discloses a polyolefin elastomer foaming coating material and a preparation method thereof. The polyolefin elastomer foaming coating material is prepared from the following raw materials in parts by weight: 25 to 40 parts of modified ethylene-octylene copolymer, 30 to 40 parts of ethylene-vinyl acetate copolymer, 3 to 5 parts of foaming agent, 1 to 3 parts of activating agent and 3 to 5 parts of filler aid, grafting the ethylene-octylene copolymer with the polyamino silicon oil in advance to form a modified ethylene-octylene copolymer; according to the prepared polyolefin elastomer foaming coating material, under the synergistic effect of all the components, the foam structure is effectively refined, the foaming effect is improved, and meanwhile the rebound resilience of the foaming material is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foaming materials, in particular to a polyolefin elastomer foaming coating material and a preparation method thereof. BACKGROUND

[0002] Artificial leather, as a widely used imitation leather material, plays an important role in the fields of shoe materials, luggage, furniture, automotive interiors, etc. Traditional artificial leather often uses polyvinyl chloride or polyurethane as the surface coating, but these materials have problems such as plasticizer migration, poor environmental friendliness, and insufficient weather resistance. In recent years, polyolefin elastomer foaming materials have gradually become a new choice for artificial leather coating due to their advantages of lightweight, recyclable, non-toxic, and environmentally friendly.

[0003] However, due to the low melt strength of current polyolefin elastomers, the polyolefin elastomer foaming material has serious bubble rupture, resulting in a rough surface and poor resilience of the foaming material, which is difficult to meet the coating requirements of artificial leather. SUMMARY

[0004] In order to improve the foaming effect of the existing polyolefin elastomer, the present application provides a polyolefin elastomer foaming coating material and a preparation method thereof.

[0005] In a first aspect, the present application provides a polyolefin elastomer foaming coating material, which adopts the following technical solution: A polyolefin elastomer foaming coating material, comprising the following raw materials by weight: 25-40 parts of modified ethylene-octene copolymer, 30-40 parts of ethylene-vinyl acetate copolymer, 3-5 parts of foaming agent, 1-3 parts of activator, and 3-5 parts of filler aid; the ethylene-octene copolymer is pre-grafted with polyamino silicone oil to form the modified ethylene-octene copolymer.

[0006] By pre-grafting the polyamino silicone oil with the ethylene-octene copolymer, the solubility of carbon dioxide in the polymer is improved, the strength of the ethylene-octene copolymer melt is increased, the foaming temperature of the polyolefin elastomer material is widened, the bubble coalescence is inhibited, the bubble growth is limited, and the foaming effect of the polyolefin elastomer is improved. The ethylene-vinyl acetate copolymer can form physical crosslinking points at the foaming temperature, inhibit excessive bubble expansion, complement the ethylene-octene copolymer, form a hard segment-soft segment composite structure, improve the bubble stability, and the modified ethylene-octene copolymer and the ethylene-vinyl acetate copolymer can be compounded to promote the prepared polyolefin elastomer to maintain good bubble morphology at high temperature, reduce the bubble diameter, and have good resilience.

[0007] Preferably, the ethylene-octene copolymer and polyamino silicone oil grafting method comprises the following specific steps: firstly, maleic anhydride, grafting aid and initiator are mixed and dissolved, then ethylene-octene copolymer is added and mixed, melt compounding reaction is carried out to obtain pretreated ethylene-octene copolymer; the pretreated ethylene-octene copolymer is dissolved and then polyamino silicone oil is added and mixed, heating reaction is carried out, and cooling, filtration and drying are carried out to obtain modified ethylene-octene copolymer.

[0008] By adopting the above technical scheme, maleic anhydride is introduced into the chain segment of the ethylene-octene copolymer, and then grafting crosslinking reaction is carried out with the polyamino silicone oil, so that the polyamino silicone oil can be firmly combined on the molecular chain of the ethylene-octene copolymer, and the grafting effect of the ethylene-octene copolymer and the polyamino silicone oil is improved.

[0009] Preferably, the melting temperature is 165-175℃, and the heating reaction temperature is 125-135℃.

[0010] Preferably, the modified ethylene-octene copolymer raw material comprises the following raw materials by weight: maleic anhydride 3-5 parts, grafting aid 3-5 parts, initiator 0.1-0.3 parts, ethylene-octene copolymer 30-40 parts, and polyamino silicone oil 1-3 parts.

[0011] Preferably, the grafting aid is styrene.

[0012] By adopting the above technical scheme, styrene is used as the grafting aid, which can improve the grafting rate of maleic anhydride and ethylene-octene copolymer, further improve the grafting effect of polyamino silicone oil and ethylene-octene copolymer, and improve the foaming effect of the polyolefin elastomer.

[0013] Preferably, the foaming agent is a mixture of azodicarbonamide and zinc oxide, and the mass ratio of azodicarbonamide to zinc oxide is (1.5-3):1.

[0014] By adopting the above technical scheme, azodicarbonamide and zinc oxide are used as the foaming agent, which can improve the foaming ratio of the polyolefin elastomer. The use of zinc oxide with azodicarbonamide can reduce the foaming decomposition temperature of azodicarbonamide, so that the processing temperature of azodicarbonamide and the polyolefin elastomer can be matched, the gas released during the foaming process of the polyolefin material can be more stable and controllable, and the phenomenon of bubble coalescence or collapse caused by too fast foaming rate of azodicarbonamide can be reduced.

[0015] Preferably, the activator is at least one of zinc stearate and citric acid.

[0016] By adopting the technical scheme, the zinc stearate can reduce the foaming temperature of azodicarbonamide, provide additional zinc ions, enhance the catalysis on the foaming agent, and promote the more stable and controllable release of gas. The zinc stearate can migrate to the cell interface, stabilize the bubble wall, reduce cell coalescence, and form a more fine and uniform closed cell structure. The citric acid can react with the azodicarbonamide group, promote the expansion of the azodicarbonamide foaming temperature, play an acidic activation role, and improve the foaming effect of the polyolefin elastomer. The citric acid and the zinc stearate can synergistically enhance each other, the zinc stearate stabilizes the cell structure and reduces the decomposition temperature of azodicarbonamide, and the citric acid promotes the decomposition of the foaming agent, effectively improves the polyolefin foaming effect, and reduces the phenomenon of large pores and collapse of the cells.

[0017] Preferably, the filler aid is at least one of carbon nanotubes, titanium dioxide, and calcium carbonate.

[0018] By adopting the technical scheme, the carbon nanotubes, titanium dioxide, and calcium carbonate are introduced into the polyolefin elastomer matrix, which can play a heterogeneous nucleation role on one hand, increase the cell density, and refine the cells; on the other hand, these fillers can be dispersed around the cells to inhibit cell coalescence, thereby maintaining a good cell structure.

[0019] In a second aspect, the application provides a preparation method of a polyolefin elastomer foaming coating material, which adopts the following technical scheme: A preparation method of a polyolefin elastomer foaming coating material, comprising the following specific steps: mixing a modified ethylene-octene copolymer, an ethylene-vinyl acetate copolymer, a crosslinking agent, and a filler aid, then adding a foaming agent and an activator for mixing, and obtaining the polyolefin elastomer foaming coating material after foaming.

[0020] By adopting the technical scheme, under the synergistic effect of various components, the prepared polyolefin elastomer has good foaming effect, refines the cell structure, inhibits cell coalescence, and maintains a good cell morphology and density.

[0021] Preferably, the mixing temperature is 150-170°C.

[0022] In summary, the application has the following beneficial effects: 1. Since the application adopts the grafting of polyamino silicone oil and ethylene-octene copolymer to form a modified ethylene-octene copolymer, the solubility strength of the ethylene-octene copolymer is improved, the ethylene-octene copolymer foaming temperature is widened, and the phenomenon of cell coalescence and collapse is reduced. The modified ethylene-octene copolymer and the ethylene-vinyl acetate copolymer promote the polyolefin elastomer prepared at high temperature to maintain a good cell morphology and improve the resilience of the polyolefin elastomer foaming material.

[0023] 2、The application adopts the method of first introducing maleic anhydride into the chain segment of ethylene-octene copolymer, then grafting and cross-linking with polyamino silicone oil, and using styrene to improve the grafting rate of maleic anhydride and ethylene-octene copolymer, so as to improve the foaming effect of polyolefin elastomer and refine the cell structure. DETAILED DESCRIPTION

[0024] The application will be further described in detail below in combination with examples.

[0025] All raw materials in the examples can be obtained by market purchase. Examples Example 1

[0026] The example provides a polyolefin elastomer foaming coating material, which comprises the following raw materials in weight parts: modified ethylene-octene copolymer 33 kg, ethylene-vinyl acetate copolymer 35 kg, foaming agent 4 kg, activating agent 2 kg, and filler aid 4 kg. The ethylene-vinyl acetate copolymer has a vinyl acetate mass content of 33% and a melt index MI of 2 g / 10 min, and is EVA UE3302 selected and purchased from Taiwan Poly Company in China, the foaming agent is azodicarbonamide, the activating agent is zinc stearate, and the filler aid is carbon nanotube with an average diameter of 5 nm and an average length of 5 nm.

[0027] The ethylene-octene copolymer is pre-grafted with polyamino silicone oil to form modified ethylene-octene copolymer, which comprises the following raw materials in weight parts: maleic anhydride 4 kg, grafting aid 4 kg, initiator 0.2 kg, ethylene-octene copolymer 35 kg, and polyamino silicone oil 2 kg. The ethylene-octene copolymer is selected and purchased from Dow Chemical Company 8100 in the United States, the polyamino silicone oil is selected and purchased from Jiangnan Textile Material Co., Ltd. in Jiashan, and the grafting aid is styrene, and the initiator is dicumyl peroxide.

[0028] A preparation method of a polyolefin elastomer foaming coating material, comprising the following specific steps: S1: maleic anhydride, grafting aid and initiator are mixed and dissolved in N, N-dimethylformamide, the mass ratio of maleic anhydride, grafting aid and initiator to N, N-dimethylformamide is 1:0.5, then ethylene-octene copolymer is added and mixed, melt-compacted and reacted at 170℃ for 10 min to obtain pretreated ethylene-octene copolymer; the pretreated ethylene-octene copolymer is dissolved in dimethylbenzene, the mass ratio of ethylene-octene copolymer to dimethylbenzene is 1:10, then polyamino silicone oil is added and mixed, heated to 130℃ and reacted for 2 h, and then filtered and dried after cooling to obtain modified ethylene-octene copolymer.

[0029] S2: mixing the modified ethylene-octene copolymer, ethylene-vinyl acetate copolymer, crosslinking agent, filler aid at 160℃, then adding the foaming agent and activator, mixing and foaming to obtain the polyolefin elastomer foaming cladding material.

[0030] Example 2

[0031] Example 2 differs from Example 1 in that the use amount of the modified ethylene-octene copolymer in the polyolefin elastomer foaming cladding material raw material is 25 kg, the use amount of the ethylene-vinyl acetate copolymer is 40 kg, the use amount of the foaming agent is 3 kg, the use amount of the activator is 1 kg, and the use amount of the filler aid is 3 kg.

[0032] Example 3 Example 3 differs from Example 1 in that the use amount of the modified ethylene-octene copolymer in the polyolefin elastomer foaming cladding material raw material is 40 kg, the use amount of the ethylene-vinyl acetate copolymer is 30 kg, the use amount of the foaming agent is 5 kg, the use amount of the activator is 3 kg, and the use amount of the filler aid is 5 kg.

[0033] Example 4 Example 4 differs from Example 1 in that the use amount of maleic anhydride in the modified ethylene-octene copolymer raw material is 3 kg, the use amount of the grafting aid is 3 kg, the use amount of the initiator is 0.1 kg, the use amount of the ethylene-octene copolymer is 40 kg, and the use amount of the polyamino silicone oil is 1 kg.

[0034] Example 5 Example 5 differs from Example 1 in that the use amount of maleic anhydride in the modified ethylene-octene copolymer raw material is 5 kg, the use amount of the grafting aid is 5 kg, the use amount of the initiator is 0.3 kg, the use amount of the ethylene-octene copolymer is 30 kg, and the use amount of the polyamino silicone oil is 3 kg.

[0035] Example 6 Example 6 differs from Example 1 in that no grafting aid is used in the modified ethylene-octene copolymer raw material.

[0036] A preparation method of a polyolefin elastomer foaming cladding material, comprising the following specific steps: S1: maleic anhydride, initiator are mixed and dissolved in N, N-dimethylformamide in advance, the mass ratio of maleic anhydride, initiator to N, N-dimethylformamide is 1:0.5, then ethylene-octene copolymer is added and mixed, melt compounding reaction is carried out at 170℃ for 10min, and the pretreated ethylene-octene copolymer is obtained; the pretreated ethylene-octene copolymer is dissolved in xylene, the mass ratio of ethylene-octene copolymer to xylene is 1:10, then polyamino silicone oil is added and mixed, heated to 130℃ for 2h, and after cooling, filtration and drying, the modified ethylene-octene copolymer is obtained.

[0037] S2: the modified ethylene-octene copolymer, ethylene-vinyl acetate copolymer, crosslinking agent, filler aid are mixed and kneaded at 160℃, then the foaming agent and the activator are added and mixed and foamed, and the polyolefin elastomer foaming cladding material is obtained.

[0038] Example 7 The difference between example 7 and example 1 is that the foaming agent in the raw material of the polyolefin elastomer foaming cladding material is a mixture of azodicarbonamide and zinc oxide, and the mass ratio of azodicarbonamide to zinc oxide is 1.5:1.

[0039] Example 8 The difference between example 8 and example 7 is that the mass ratio of azodicarbonamide to zinc oxide in the foaming agent in the raw material of the polyolefin elastomer foaming cladding material is 3:1.

[0040] Example 9 The difference between example 9 and example 8 is that the activator in the raw material of the polyolefin elastomer foaming cladding material is a mixture of citric acid and zinc stearate, and the mass ratio of citric acid to zinc stearate is 1:1.

[0041] Comparative example Comparative example 1 The difference between comparative example 1 and example 1 is that the same amount of ethylene-octene copolymer is used instead of modified ethylene-octene copolymer in the raw material of the polyolefin elastomer foaming cladding material. The ethylene-octene copolymer is selected from Dow Chemical Company 8100.

[0042] A preparation method of a polyolefin elastomer foaming cladding material, comprising the following specific steps: The ethylene-octene copolymer, ethylene-vinyl acetate copolymer, crosslinking agent, filler aid are mixed and kneaded at 160℃, then the foaming agent and the activator are added and mixed and foamed, and the polyolefin elastomer foaming cladding material is obtained.

[0043] Comparative example 2 The difference between comparative example 2 and example 1 is that the ethylene-vinyl acetate copolymer is not used in the raw material of the polyolefin elastomer foaming cladding material

[0044] According to the polyolefin elastomer foamed cladding materials provided by Examples 1-9 and Comparative Examples 1-2 of the present application, the following performance tests were conducted, and the specific test results are shown in Table 1.

[0045] Test method I. Foaming effect The polyolefin elastomer foamed cladding material sample prepared in the present application was brittle fractured after being frozen in liquid nitrogen for 30 min, and the fracture surface was sprayed with gold for observation of the fracture surface morphology. The cell diameter d and cell density N0 were analyzed by Image Pro Plus software, and the calculation formula (1) was as follows: d =∑(d i n i ) / ∑n i ; In formula (1), d is the cell diameter, μm; n is the number of cells with a diameter of di, pieces.

[0046] The calculation formula (2) was as follows: N0=(n / A) 3 / 2 (ρ / ρ f ); In formula (2), N0 is the cell density, pieces / cm 3 ; n is the number of cells in the statistical area, pieces; A is the statistical area selected in the electron microscope photograph, cm 2 ; ρ f and ρ are the densities of the foamed material and the unfoamed material, respectively, g / cm 3 .

[0047] II. Resilience The diameter of the sample was measured by a vernier caliper, then the sample was compressed to 1 / 2 of the diameter by a caliper, released after 5 s, and the diameter of the compressed part was measured by the caliper again after 1 min. The formula for calculating the resilience was as follows: resilience = (size after resilience-1 / 2 diameter) / (1 / 2 diameter)*100%.

[0048] III. Density According to the standard of STM D792-2007 "Test method for density and relative density of plastics", the density of the polyolefin elastomer foamed cladding material prepared in the present application was measured by the buoyancy method. The mass of the sample at room temperature was weighed and recorded as M a , then the sample was immersed in deionized water by an iron ring, and the mass was measured and recorded as M b . The foamed material density formula ρ f was calculated as follows: ρ f = [( Ma / (M a -M b )]ρ w ; in the formula, ρw is the density of deionized water, g·cm -3.

[0049] Table 1: Performance test result data table

[0050] From the performance test results, it can be seen that the polyolefin elastomer foaming coating material prepared in the application has good foaming effect. After grafting with polyamino silicone oil and ethylene-octene copolymer, the bubble holes are inhibited and aggregated, the bubble hole growth is limited, and the foaming effect of the polyolefin elastomer is improved. By comparing Comparative Example 1-2 and Example 1, it can be seen that an equal amount of ethylene-octene copolymer is used instead of modified ethylene-octene copolymer in Comparative Example 1. From the performance test results, it can be seen that the bubble holes of the polyolefin elastomer foaming coating material are significantly larger, the resilience of the foaming material is reduced, and the bubble hole density is also reduced, which further indicates that the modification of polyamino silicone oil on ethylene-octene copolymer can better refine the bubble hole structure and improve the foaming effect of the polyolefin elastomer. In Comparative Example 2, ethylene-vinyl acetate copolymer is not used. From the performance test results, it can be seen that the foaming effect of the polyolefin elastomer material is also significantly reduced.

[0051] By comparing Example 6 and Examples 1-5, it can be seen that in the grafting modification process of polyamino silicone oil and ethylene-octene copolymer, using styrene as a grafting aid can effectively promote the grafting effect of polyamino silicone oil and ethylene-octene copolymer.

[0052] From Examples 7-8, it can be seen that by compounding azodicarbonamide and zinc oxide as a foaming agent, the foaming effect of the polyolefin elastomer can be effectively improved.

[0053] The specific embodiments are only an explanation of the application, and are not a limitation of the application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, as long as the modifications are within the scope of the claims of the application.

Claims

1. A polyolefin elastomer foam coating material, characterized in that, The raw materials include the following parts by weight: 25-40 parts of modified ethylene-octene copolymer, 30-40 parts of ethylene-vinyl acetate copolymer, 3-5 parts of foaming agent, 1-3 parts of activator, and 3-5 parts of filler additive; the ethylene-octene copolymer is pre-grafted with polyamino silicone oil to form modified ethylene-octene copolymer.

2. The polyolefin elastomer foam coating material according to claim 1, characterized in that, The grafting method of the ethylene-octene copolymer with polyamino silicone oil includes the following specific steps: maleic anhydride, grafting aid, and initiator are mixed and dissolved in advance, and then the ethylene-octene copolymer is added and mixed, and melt-mixed to obtain a pretreated ethylene-octene copolymer; the pretreated ethylene-octene copolymer is dissolved and then mixed with polyamino silicone oil, heated to react, cooled, filtered and dried to obtain a modified ethylene-octene copolymer.

3. The polyolefin elastomer foam coating material according to claim 2, characterized in that, The melting temperature is 165-175℃, and the heating reaction temperature is 125-135℃.

4. The polyolefin elastomer foam coating material according to claim 2, characterized in that, The modified ethylene-octene copolymer raw material comprises the following parts by weight: 3-5 parts maleic anhydride, 3-5 parts grafting agent, 0.1-0.3 parts initiator, 30-40 parts ethylene-octene copolymer, and 1-3 parts polyamino silicone oil.

5. The polyolefin elastomer foam coating material according to claim 4, characterized in that, The grafting aid is styrene.

6. The polyolefin elastomer foam coating material according to claim 1, characterized in that, The foaming agent is a mixture of azodicarbonamide and zinc oxide, with a mass ratio of azodicarbonamide to zinc oxide of (1.5-3):

1.

7. The polyolefin elastomer foam coating material according to claim 6, characterized in that, The activator is at least one of zinc stearate and citric acid.

8. The polyolefin elastomer foam coating material according to claim 6, characterized in that, The filler additive is at least one of carbon nanotubes, titanium dioxide, and calcium carbonate.

9. A method for preparing a polyolefin elastomer foam coating material as described in any one of claims 1-8, characterized in that, The specific steps include: mixing modified ethylene-octene copolymer, ethylene-vinyl acetate copolymer, and filler additives, then adding foaming agent and activator, and obtaining polyolefin elastomer foamed coating material after foaming.

10. The method for preparing the polyolefin elastomer foam coating material according to claim 9, characterized in that, The mixing temperature is 150-170℃.

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