Super-durable PVC foaming layer, super-durable PVC artificial leather and preparation method of super-durable PVC foaming layer

Abstract

The invention relates to the technical field of PVC artificial leather, in particular to a super-durable PVC foaming layer, super-durable PVC artificial leather and a preparation method of the super-durable PVC artificial leather. A traditional plasticizer applied to a PVC artificial leather material is not environment-friendly enough, or the plasticizing effect is poor, the overall performance of artificial leather is influenced by the poor foaming effect of a PVC foaming layer, and in addition, the PVC artificial leather material has the problems of high surface glossiness, poor mechanical strength and poor use durability. The PVC artificial leather is obtained by synthesizing the PVC foaming layer, the PVC layer and the modified waterborne polyurethane layer and finally compounding with the base cloth. The preparation method comprises the following steps: synthesizing a bio-based plasticizer, matching the bio-based plasticizer with other plasticizers, reasonably adjusting the conditions for synthesizing a PVC foaming layer, preparing a matting and wear-resistant modified waterborne polyurethane layer, selecting proper plant source fibers as a base cloth raw material, and reasonably adjusting the conditions for preparing the PVC artificial leather. The obtained PVC foaming layer and PVC artificial leather are good in durability.

Description

Technical Field

[0001] The present invention relates to the technical field of PVC artificial leather, in particular to a super-durable PVC foaming layer, a super-durable PVC artificial leather and a preparation method thereof. Background Art

[0002] Animal dermis is widely used in industries such as footwear, luggage, clothing and furniture. However, due to the shortage of natural resources and for the protection of animal resources and cost reduction, in the 1930s, people synthesized PVC artificial leather to replace genuine leather. PVC artificial leather is inexpensive and has a simple processing technology. However, with the development of the economy and society, the application scope of PVC artificial leather has been further expanded, and higher requirements have been put forward for the feel, leather feel, comfort, cold resistance, environmental protection, etc. of PVC artificial leather.

[0003] The overall PVC artificial leather is composed of a base fabric layer, a PVC foaming layer and a PVC skin layer. The density of the PVC foaming layer needs to be controlled within a suitable range. If the foaming density is too large, the overall weight of the material will increase, which does not conform to the demand trend for lightweight and high-quality materials; if the foaming density is too small, the overall mechanical properties of the material will be reduced. Controlling the foaming effect of the PVC foaming layer is crucial.

[0004] Plasticizers are usually added during the preparation of the PVC foaming layer and the PVC skin layer to increase the molecular spacing of PVC, weaken the intermolecular force, lower the plasticization temperature, reduce the brittleness of the PVC material, and solve the problem of low tensile strength of the PVC material. Commonly used plasticizers include phthalate plasticizers, phosphate esters and epoxy compounds, etc., but there are many problems such as carcinogenicity, non-environmental protection and high price. Patent CN111321608B discloses an "epidermal layer composition, foaming layer composition and formed environmentally friendly PVC artificial leather", in which an environmentally friendly plasticizer is obtained by compounding epoxy soybean oil and trimellitate ester. The PVC artificial leather has good mechanical properties and a good feel, increases the proportion of non-petroleum-based materials, and meets the requirements of environmental protection and renewable resources. However, the epoxy soybean oil has poor permeability and increases the processing difficulty. In addition, using edible oil as a raw material to obtain an environmentally friendly plasticizer wastes food resources.

[0005] The selection of raw materials and the preparation method of the base fabric layer will affect the mechanical properties of PVC artificial leather. To solve the problems of poor toughness and low strength of PVC artificial leather and improve the overall mechanical effect. Patent CN108824008B discloses "a PU / PVC composite artificial leather imitating ultra-fine fibers and a preparation method thereof", and the composite artificial leather is obtained by impregnating the imitated ultra-fine fibers. The artificial leather meets the environmental protection standards and has good mechanical properties.

[0006] To solve the problem of poor abrasion and scratch resistance of PVC artificial leather, Patent CN112900109B discloses "A High-performance Environmentally Friendly PVC Artificial Leather and Its Preparation Method", which uses PVC resin, plasticizer, functional adsorption antibacterial agent, thermoplastic polyurethane elastomer, compatibilizer, crosslinking agent, heat stabilizer and foaming agent as raw materials. By changing the component dosage and preparation conditions, the problems of poor abrasion resistance, poor antibacterial effect, and easy mildew and peeling of PVC artificial leather are overcome.

[0007] Patent CN117986772A discloses a "Super-durable PVC Foaming Layer, Super-durable PVC Artificial Leather and Its Preparation Method", which overcomes the problems of poor high and low temperature resistance, poor folding resistance and poor amine resistance of PVC artificial leather by using low and high temperature resistant plasticizers, using a new type of mineral-based endothermic foaming agent, and mixing and adding modified lignocellulose and modified nano-silica in the PVC skin layer.

[0008] To make PVC artificial leather have better mechanical properties, higher abrasion resistance, adapt to high and low temperature usage conditions, and lighter texture, and extend its service life, it is necessary to develop a product with extremely high durability.

[0009] Therefore, a super-durable PVC foaming layer, super-durable PVC artificial leather and its preparation method are proposed. Summary of the Invention

[0010] The purpose of the present invention is to provide a super-durable PVC foaming layer, super-durable PVC artificial leather and its preparation method. By using castor oil acid, acid anhydride and polyol as raw materials, a bio-based plasticizer is prepared and used in combination with other plasticizers and applied to the PVC foaming layer. The obtained PVC foaming layer has high tensile strength and good elongation at break, and at the same time reduces the processing temperature of PVC resin. By using a foaming agent, the prepared PVC foaming layer has a low density, which helps to obtain a lightweight PVC artificial leather material. The prepared modified waterborne polyurethane is scraped on the surface of the PVC layer, and the obtained PVC artificial leather has low gloss and good abrasion resistance. By using plant-derived fiber and carbon fiber as raw materials for the base fabric; reasonably adjusting the dosage and ratio of each component of the PVC artificial leather, the prepared PVC artificial leather has high mechanical strength, high and low temperature resistance, and aging resistance. The PVC foaming layer and PVC artificial leather have long-term use durability.

[0011] To achieve the above object, the present invention provides the following technical solutions:

[0012] The present invention provides a preparation method for a super-durable PVC foaming layer, comprising the following steps:

[0013] Cast castor oil and acid anhydride into a three-necked flask, react for 5 hours, and refine to obtain refined modified ricinoleic acid; add a polyol solution and butadiene-styrene to the refined modified ricinoleic acid to obtain a reaction solution; heat up the reaction solution and reflux to obtain a modified ricinoleate precursor; wash the modified ricinoleate precursor, separate the liquid, and distill under reduced pressure to obtain a modified ricinoleate; add formic acid and ethyl acetate to the modified ricinoleate, heat up, and dropwise add hydrogen peroxide solution to obtain a plasticizer reaction solution; stir and react the plasticizer reaction solution, add KH550, continue to react for 6h, wash with water for neutralization, and distill under reduced pressure to obtain plasticizer one;

[0014] Vacuum stir PVC resin, plasticizer and 13 - 17 parts of foaming agent to obtain a mixture; the ratio of sodium bicarbonate, coconut oil ethylene glycol amine, azodicarbonamide and toluene diisocyanate in the foaming agent is 0 - 6:1.5 - 2:9 - 10:7 - 9.5; the plasticizer includes plasticizer one and plasticizer two; the ratio of plasticizer one and plasticizer two is 0 - 17:1 - 3; transfer the mixture to a sealed mold, vulcanize, cool, pop out and put it into a constant temperature water tank for curing to obtain the super-durable PVC foaming layer;

[0015] The PVC resin is one of SG-8, BY650 and SG-5;

[0016] The information of the PVC resin is shown in the following table:

[0017]

[0018]

[0019] The acid anhydride is one of maleic anhydride, succinic anhydride, itaconic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, dicyclooct-7-ene tetracarboxylic dianhydride, tricyclonon-8-ene dicarboxylic anhydride and (2,7-octadien-1-yl) succinic anhydride;

[0020] The polyol is one of mesityl alcohol and 1,4-butanediol.

[0021] Preferably, the plasticizer two is one of tributyl citrate and acetyl tributyl citrate.

[0022] Preferably, the ratio of sodium bicarbonate, coconut oil ethylene glycol amine, azodicarbonamide and toluene diisocyanate is 4 - 6:1.5 - 2:9 - 10:8.

[0023] After sodium bicarbonate decomposes upon heating, water and carbon dioxide are released, providing a powerful driving force for foaming and promoting the growth of bubbles. On the other hand, during the heating process of vulcanization, water reacts with diisocyanate to form amine and carbon dioxide. The amine quickly reacts with diisocyanate to form a ureido group, and the ureido group further reacts with diisocyanate to form a polyurea structure compound, which forms a physical entanglement structure with the PVC molecular chain, endowing the system with good elasticity, impact resistance, and tensile properties. As the amount of the polyurea structure compound generated increases, the viscosity of the system gradually increases.

[0024] Preferably, the ratio of the amount of the first plasticizer to the amount of the second plasticizer is 4 - 17:1 - 3.

[0025] The present invention also provides a method for preparing a super-durable PVC artificial leather, comprising the following steps:

[0026] Mix plant-derived fibers and carbon fibers in a ratio of 0 - 13:9 - 87 by weight to obtain mixed fibers; card the mixed fibers to prepare a fibrous web in the form of a film; reinforce the fibrous web in the form of a film to obtain a base fabric;

[0027] Mix 94 - 108 parts of PVC resin, 5 - 18 parts of solution-polymerized styrene-butadiene rubber, 30 - 60 parts of plasticizer, 1 - 7 parts of stabilizer, 1.5 - 3 parts of antioxidant, processing heat stabilizer, and 1 - 2 parts of ultraviolet absorber to obtain a mixture; subject the mixture to primary refining and refining to obtain a PVC slurry; the temperature of the primary refining and refining is 170 °C; the PVC slurry is calendered to obtain a PVC layer;

[0028] Solution-polymerized styrene-butadiene rubber can improve the high-temperature and low-temperature resistance of PVC artificial leather. The synthesized plasticizer increases the flexibility of PVC molecules, and is also beneficial to improving the high-temperature and low-temperature resistance effect of super-durable PVC artificial leather.

[0029] The ultraviolet absorber is nano-titanium dioxide; after nano-titanium dioxide absorbs ultraviolet photons with energy greater than or equal to its band gap, the electrons in the valence band are excited to the conduction band, thereby generating highly active free-moving photoelectrons and holes in the valence band and the conduction band respectively. The electron-hole pairs generated after its absorption of ultraviolet light can dissociate into free holes and free electrons that freely migrate to the surface of the crystal lattice or other reaction sites in the crystal lattice, and are immediately captured by surface groups. Therefore, it has good ultraviolet resistance, but excessive addition will have an adverse effect on the surface and mechanical properties of PVC artificial leather.

[0030] Mix waterborne matte polyurethane, 0 - 3.5 parts of fumed silica, 0 - 4 parts of nano-inorganic boron nitride, leveling agent, nano-cellulose crystal, 0.3 - 0.6 parts of curing agent, and defoaming agent to obtain a modified waterborne polyurethane precursor; grind the modified waterborne polyurethane precursor to an average particle size of 30 - 60 μm to obtain a modified waterborne polyurethane;

[0031] After laminating the super-durable PVC foam layer with the PVC layer, the modified aqueous polyurethane is scrape-coated on the surface of the PVC layer; the modified aqueous polyurethane is cured for 48 h to obtain a modified aqueous polyurethane layer; the modified aqueous polyurethane layer, the super-durable PVC foam layer, the PVC layer and the base fabric are laminated, surface-treated, embossed and cooled to obtain the super-durable PVC artificial leather.

[0032] Preferably, the ratio of the plant-derived fiber to the carbon fiber is 1-13:9-87; the plant-derived fiber is one of calcium alginate fiber, chitosan fiber, lignin fiber and jute fiber.

[0033] Preferably, the aqueous matting polyurethane is one of WR-8394A type and 549 type; the leveling agent is 540# leveling agent; the curing agent is DN curing agent; the defoaming agent is Cl-937; the processing heat stabilizer is organotin 181; the antioxidant is B900; the ultraviolet absorber is nano-titanium dioxide.

[0034] Preferably, the amount of the fumed silica is 1.5-3.5 parts; the amount of the nano-inorganic boron nitride is 2-4 parts.

[0035] Preferably, the amount of the PVC resin is 94-100 parts; the amount of the solution-polymerized styrene-butadiene rubber is 15-18 parts; the amount of the plasticizer is 54-60 parts; the plasticizer is plasticizer one and plasticizer two; the plasticizer two is tributyl citrate; the amount of the stabilizer is 5-7 parts; the stabilizer is two of sodium perchlorate, citric acid, trifluoroacetic anhydride and methyl succinic anhydride.

[0036] Amines are liable to carry out a binding reaction with the PVC material to generate other harmful small molecules such as hydrochloric acid, and at the same time cause the PVC material to turn yellow, affecting the beauty of the PVC artificial leather. Adding sodium perchlorate, citric acid, trifluoroacetic anhydride and methyl succinic anhydride can enable the amines to combine with them, thereby reducing the adverse effects of the amines on the PVC artificial leather.

[0037] Again, the present invention also provides a super-durable PVC foam layer and a super-durable PVC artificial leather. The super-durable PVC foam layer comprises PVC resin, a plasticizer and a foaming agent; the super-durable PVC artificial leather comprises a base fabric, the PVC foam layer, a PVC layer and a modified waterborne polyurethane layer; the super-durable PVC foam layer is prepared by the preparation method described in any one of the above; the super-durable PVC artificial leather is prepared by the preparation method described in any one of the above; the tensile strength of the super-durable PVC foam layer is 9.2 - 13.2 MPa, the elongation at break is 375% - 456%, and the glass transition temperature is 38 - 73 °C; the foaming density of the super-durable PVC foam layer is 0.17 - 0.43 g·cm -3 ; the 60° gloss of the super-durable PVC artificial leather is 4.3 - 10.2, and only the surface gloss changes after abrasion testing; the notched impact strength of the super-durable PVC artificial leather material is 52.5 - 67.4 J / m, and the tensile strength is 9.4 - 16.6 MPa; the super-durable PVC artificial leather does not crack after 40,000 - 100,000 times under the conditions of 100 °C and ultraviolet irradiation; the PVC artificial leather does not crack after 50,000 - 100,000 times after -20 °C low-temperature test; the results of the amine resistance test show no obvious color change, and the Da value is 0.4 - 1.4.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] 1. By using ricinoleic acid as the main raw material of the bio-based plasticizer, and introducing an acid anhydride under heating conditions, the acid anhydride decomposes into two molecules of acid, and the acid reacts with the hydroxyl group of ricinoleic acid to obtain modified ricinoleic acid; the hydroxyl group of the polyol reacts with the modified ricinoleic acid under reflux to obtain modified castor oil; under acidic conditions, hydrogen peroxide oxidizes the unsaturated bond in the modified castor oil to an epoxy group, and after the epoxy group is ring-opened, a silane coupling agent is used for end-capping to obtain a bio-based plasticizer. When used in combination with other plasticizers, the super-durable PVC foam layer has good tensile strength and elongation at break, improves the original large brittleness of the PVC material, reduces the glass transition temperature of the PVC, and thus reduces its processing temperature.

[0040] 2. By using sodium bicarbonate, coconut oil ethylene glycol amine, azodicarbonamide and toluene diisocyanate as foaming agents to obtain a super-durable PVC foam layer, the foaming effect is good. Sodium bicarbonate provides power for the growth of system bubbles, coconut oil ethylene glycol amine plays a good lubricating role for the components, the decomposition of sodium bicarbonate and the volatilization of azodicarbonamide at high temperature promote the formation of bubble structures, and by reasonably adjusting the ratio of the four substances, the super-durable PVC foam layer has a low density and is light in weight.

[0041] 3. By introducing fumed silica and nano-inorganic boron nitride, on the one hand, the surface roughness of the cured modified waterborne polyurethane is increased, achieving a matting effect; on the other hand, the addition of fumed silica improves the high-temperature resistance and hydrophobicity of the surface of the super-durable PVC artificial leather, and the addition of nano-inorganic boron nitride improves the wear resistance of the surface of the super-durable PVC artificial leather. By selecting a suitable type of waterborne matting polyurethane and reasonably adjusting the dosage and particle size of fumed silica, nano-inorganic boron nitride, and curing agent, a modified waterborne polyurethane layer with good low gloss and excellent wear resistance is prepared.

[0042] 4. In the present invention, carbon fiber and plant-derived fiber are used as raw materials for the base fabric. By utilizing the rigidity of carbon fiber and the toughness and flexibility of plant-derived fiber, the super-durable PVC artificial leather prepared has good impact resistance and tensile strength. The PVC artificial leather has both compressive and toughness effects and is durable. In addition, carbon fiber and plant-derived fiber have good biodegradability and good environmental protection.

[0043] 5. By changing the type of stabilizer and the ratio of components and reasonably controlling the dosage of PVC resin, solution-polymerized styrene-butadiene rubber, plasticizer, stabilizer, antioxidant, and ultraviolet absorber, the super-durable PVC artificial leather obtained has good high-temperature resistance, low-temperature resistance, and aging resistance. By selecting a suitable stabilizer, the final material has good amine resistance. Brief Description of the Drawings

[0044] Figure 1 It is the SEM effect diagram of Example 23 of the present invention;

[0045] Figure 2 It is the test result diagram of the mechanical properties of the super-durable PVC artificial leather of Example 42 of the present invention. Detailed Embodiments

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0047] Please refer to Figures 1 to 2 , the present invention provides a super-durable PVC foaming layer, a super-durable PVC artificial leather and its preparation method, and the technical solutions are as follows:

[0048] The substances involved in the present invention are as follows:

[0049] Benzyl alcohol CAS: 4464-18-0; maleic anhydride CAS: 108-31-6; succinic anhydride CAS: 108-30-5; bean anhydride CAS: 623-68-7; hexahydrophthalic anhydride CAS: 13149-00-3; tetrahydrophthalic anhydride CAS: 935-79-5; bicyclooct-7-ene tetracarboxylic dianhydride CAS: 1719-83-1; tricyclonon-8-ene dicarboxylic anhydride CAS: 24447-28-7; (2,7-octadien-1-yl) succinic anhydride CAS: 142826-45-7; antioxidant B900 purchased from Guangzhou Yuchang Polymerization Technology Co., Ltd.; matting powder TS100 was purchased from Dongguan Meiyang Trading Co., Ltd.; WR-8394A water-based matte polyurethane coating was purchased from Meijiale Environmental Protection New Materials Co., Ltd.; 549 water-based matte polyurethane coating was purchased from Stahl of the Netherlands; ordinary water-based polyurethane was purchased from Huizhou Zhongda New Materials Technology Co., Ltd.; PVC resins SG-8, SG-5 and BY650 were all purchased from Shaanxi Beiyuan Chemical Group Co., Ltd.; Cl-937 defoamer was purchased from Guangdong Nanhui New Materials Co., Ltd.; 540# leveling agent was purchased from Xiamen Aikema Chemical Co., Ltd.; DN curing agent was purchased from Beijing Kemite Technology Development Co., Ltd.

[0050] Example 1

[0051] Castor oil acid and acid anhydride were put into a three-necked flask at a molar mass ratio of 1:0.6 and reacted at 130 °C for 5 hours to obtain modified castor oil acid; the acid anhydride was maleic anhydride; after the modified castor oil acid was cooled to room temperature, it was washed with deionized water and distilled under reduced pressure to obtain refined modified castor oil acid; the polyol was dissolved in methanol to obtain a polyol solution; the mass (g) to volume (mL) ratio of the polyol to methanol was 1:60; the polyol was 1,3,5-tris(benzyloxy)benzene; the 1,3,5-tris(benzyloxy)benzene solution was mixed with the modified castor oil acid in a condensing reflux device, and then styrene-butadiene was added to obtain a reaction solution; the molar mass ratio of the modified castor oil acid to 1,3,5-tris(benzyloxy)benzene in the reaction solution was 3.2:1; the reaction solution was heated to 115 °C and reacted for 12.5 h to obtain a modified castor oil ester precursor; at this time, the water yield was close to the theoretical value; the modified castor oil ester precursor was cooled to room temperature, washed with a 5% sodium bicarbonate solution by mass and then washed with deionized water, and finally separated and distilled under reduced pressure to obtain a modified castor oil ester; the modified castor oil ester and formic acid were put into a three-necked flask, and ethyl acetate with a mass 10 times that of the modified castor oil ester was added and mixed to obtain a precursor of a plasticizer reaction solution; the molar mass ratio of the modified castor oil ester to formic acid was 1:0.7; the precursor of the plasticizer reaction solution was heated to 50 °C, and a hydrogen peroxide solution was added dropwise to obtain a plasticizer reaction solution; the molar mass ratio of hydrogen peroxide to the modified castor oil ester was 4.9:1; the plasticizer reaction solution was heated to 60 °C and stirred for 6 h to obtain a plasticizer precursor; KH550 was added to the plasticizer precursor and stirred for 6 h to obtain a plasticizer intermediate; the molar mass ratio of KH550 to the modified castor oil ester was 6.2:1; the plasticizer intermediate was washed with water for neutralization and distilled under reduced pressure to obtain plasticizer one. All reaction processes were carried out under nitrogen protection.

[0052] The plant-derived fiber and carbon fiber were mixed at a parts ratio of 1:9 to obtain a mixed fiber; the plant-derived fiber was calcium alginate fiber; the mixed fiber was put into a digital small-sample carding and drawing unit and carded to prepare a fibrous web in the form of a film; a needle punching composite small machine was used to reinforce the fibrous web in the form of a film to obtain a base fabric.

[0053] 100 parts of PVC resin, 55 parts of plasticizer, and 17 parts of foaming agent are added to a high-speed disperser and stirred under vacuum to obtain a mixture; the ratio of the number of parts of sodium bicarbonate, coconut oil ethylene glycol amine, azodicarbonamide, and toluene diisocyanate in the foaming agent is 4:1.5:9:8; the PVC resin model is SG-8; the plasticizer includes plasticizer one and plasticizer two; the ratio of the number of parts of plasticizer one and plasticizer two is 4:1; plasticizer two is tributyl citrate; the mixture is placed in a sealed mold and vulcanized in a flat vulcanizer at a vulcanization temperature of 170 °C, a pressure of 11 MPa, and a vulcanization time of 6 min to obtain a PVC foaming layer precursor; the PVC foaming layer precursor is cooled to 80 °C, ejected from the mold and placed in a constant temperature water bath at 85 °C, and after 50 min, a PVC foaming layer intermediate is obtained; the PVC foaming layer intermediate is cured in an 80 °C environment for 20 d to obtain a super-durable PVC foaming layer.

[0054] 100 parts of PVC resin, 18 parts of solution-polymerized styrene-butadiene rubber, 60 parts of plasticizer, 6 parts of stabilizer, 3 parts of antioxidant, 2 parts of processing heat stabilizer, and 1.5 parts of ultraviolet absorber are mixed to obtain a mixture; then, through the processes of primary refining and refining, a PVC slurry is obtained; the processing heat stabilizer is organotin 181, the stabilizer is sodium perchlorate, the antioxidant is B900, and the ultraviolet absorber is nano-titanium dioxide; the temperature of primary refining and refining is 170 °C; the PVC slurry is calendered to obtain a PVC layer.

[0055] The preparation method of the modified waterborne polyurethane is as follows: 50 parts of WR-8394A type waterborne matte polyurethane, 3 parts of fumed silica, 2 parts of nano-inorganic boron nitride, 1.5 parts of 540# leveling agent, 1.5 parts of nano-cellulose crystal, 0.3 parts of DN curing agent, and 0.6 parts of Cl-937 defoaming agent are mixed to obtain a modified waterborne polyurethane precursor; the modified waterborne polyurethane precursor is ground to an average particle size of 60 μm to obtain the modified waterborne polyurethane.

[0056] After laminating the super-durable PVC foaming layer and the PVC layer, the modified waterborne polyurethane is scrape-coated on the surface of the PVC layer and cured at 60 °C for 48 h to obtain a modified waterborne polyurethane layer; finally, it is laminated with the base fabric, surface-treated, embossed, and cooled to obtain a super-durable PVC artificial leather.

[0057] The specific preparation method is shown in Table 1.

[0058] Table 1 Preparation conditions for the preparation process of plasticizer one and the preparation process of the super-durable PVC foaming layer

[0059]

[0060] Comparative Example 1

[0061] The difference from Example 1 is that the polyol is 1,4-butanediol.

[0062] Comparative Example 2

[0063] Different from Example 6, plasticizer two is tributyl citrate, and the dosage of plasticizer one is 0 part.

[0064] Example 12

[0065] The super-durable PVC foamed layers prepared in Examples 1-11 and Comparative Examples 1 and 2 were subjected to mechanical property and thermodynamic property tests. The specific test methods are as follows: The tensile strength and elongation at break of the materials were measured using a universal testing machine at room temperature, and the test speed was 10 mm / min. The glass transition temperature (Tg) of the materials was measured according to ASTM D7028-07(2015) Standard Test Method for Determining the Glass Transition Temperature (Tg) of Polymer Matrix Composites by Dynamic Mechanical Analysis (DMA). All test results were averaged after being measured 5 times. The final test results are recorded in Table 2.

[0066] Table 2 Test Results of Mechanical Properties and Thermodynamic Properties of Super-durable PVC Foamed Layers

[0067] Group Tensile strength (MPa) Elongation at break (%) Tg (°C) Example 1 13.2 382 46 Example 2 13.0 375 42 Example 3 12.3 396 50 Example 4 11.9 414 55 Example 5 11.2 417 53 Example 6 11.6 425 59 Example 7 10.5 434 73 Example 8 9.2 456 65 Example 9 11.4 428 56 Example 10 12.0 419 60 Example 11 11.8 430 68 Comparative Example 1 13.1 395 38 Comparative Example 2 12.0 420 61

[0068] By synthesizing bio-based plasticizers and using them together with tributyl citrate or acetyl tributyl citrate in the PVC foamed layer, the obtained super-durable PVC foamed layer has a tensile strength of 9.2-13.2 MPa, an elongation at break of 375%-456%, and a Tg of 38-73 °C. In Examples 1-8, by changing the type of anhydride, the tensile strength, elongation at break, and glass transition temperature gradually changed. Among them, the elongation at break increased for anhydrides with large molecular weights and long alkane chains. As shown in Example 8, the elongation at break was the highest; after hydrolysis, the anhydrides containing six-membered rings were introduced into the plasticizer, and due to the overall increase in rigidity, as shown in the results of Examples 4-7, the elongation at break decreased compared to Example 8, but the glass transition temperature increased. The results of Examples 6, 10, and 11 show that under the condition that the ratio of the amounts of plasticizer one and plasticizer two in Example 11 is 17:3, the mechanical properties are the best. In Comparative Example 1, a bio-based plasticizer was synthesized using 1,4-butanediol as a raw material, and the glass transition temperature decreased compared to the results of the examples. In Comparative Example 2, an environmentally friendly plasticizer was used to obtain a super-durable PVC foamed layer, and the plasticizer prepared in the examples of the present invention achieved similar or even better effects. In summary, the super-durable PVC foamed layer prepared by the present invention has good mechanical properties and a reduced glass transition temperature.

[0069] Examples 13-24

[0070] Different from Example 11, the following preparation conditions were changed, as specifically shown in Table 3. The four substances in Table 3 are sodium bicarbonate, coconut oil ethylene glycol amine, azodicarbonamide, and toluene diisocyanate in sequence.

[0071] Comparative Example 3

[0072] Different from Example 13, sodium bicarbonate was not added, and the mass ratios of the other three components remained unchanged.

[0073] Comparative Example 4

[0074] Different from Example 13, only azodicarbonamide was used as the foaming agent.

[0075] Example 25

[0076] The super-durable PVC foamed layers prepared in Examples 13 - 24 and Comparative Examples 3 and 4 were subjected to density tests, and at the same time, the foamed layers of the examples and comparative examples were observed by scanning electron microscopy. The calculation formula for the cell density of the foamed layer is as follows, ρ=(n / A) 3 / 2 R, where ρ is the cell density, with the unit of cells / cm 3 , n is the number of cells in the statistical area in the electron microscope, with the unit of pieces, and A is the area of the statistical area in the electron microscope, with the unit cm 2 ; the measurement results are shown in Table 3; the SEM measurement results of Example 23 are as Figure 1 shown.

[0077] The smaller the foaming density, the more uniform the bubble size and spacing, and the better the foaming effect of the foaming agent.

[0078] Table 3 Preparation methods and dosages of foaming agents

[0079]

[0080]

[0081] As Figure 1 shown, for the super-durable PVC foamed layer obtained by using the foaming agent prepared by the present invention, the bubbles are dense and the pores are uniform, and the foaming effect of the foaming agent is good. Combining the test results in Table 3, the foaming density is 0.17 - 0.43 g·cm -3In Examples 13 - 17, with the decrease in the dosage of the foaming agent, the foaming density showed a trend of first decreasing and then increasing. When the dosage of the foaming agent in Example 15 was 14.5 parts, the foaming density was the lowest. The results of Examples 15, 18, and 19 showed that when the dosage of sodium bicarbonate was increased in Example 18, the foaming density decreased, but further increasing the dosage led to an increase in density. A small amount of substance addition resulted in insufficient foaming ability and an increase in density, while excessive addition increased the system viscosity and foaming resistance, thus increasing the density. In Examples 20 - 22, with the increase in the dosage of azodicarbonamide in the components, the density gradually increased. The results of Examples 20, 23, and 24 showed that when the PVC resin model was BY650, the foaming density was the smallest. Within a certain range, the lower the average degree of polymerization of the PVC resin, the better the stability and uniformity of the bubbles, and the lower the foaming density.

[0082] Examples 26 - 32

[0083] Different from Example 1, the preparation process of the modified waterborne polyurethane layer was changed, and the detailed information is shown in Table 4.

[0084] Table 4 Preparation conditions of the modified waterborne polyurethane layer

[0085]

[0086] Example 33

[0087] Different from Example 26, 50 parts of the waterborne matte polyurethane were replaced with 48.6 parts of the ordinary waterborne polyurethane and 1.4 parts of the TS100 matte powder.

[0088] Example 34

[0089] The super - durable PVC artificial leather obtained from Examples 26 - 33 and Comparative Example 5 was subjected to surface glossiness testing and abrasion resistance testing. The specific testing methods are as follows: The glossiness of the PVC artificial leather was tested using a YG60 type 60° high - precision glossiness meter on the surface of the PVC artificial leather. Two points were randomly selected for detection. If the error between the two points did not exceed 8%, the average value of the photometric values between the two points was taken as the glossiness of the PVC artificial leather. The friction effect of the PVC artificial leather surface was tested using the friction belt method, and the wear time was 5 h. The results of the friction test were recorded. All the results are recorded in Table 5.

[0090] Table 5 Results of glossiness testing and abrasion resistance testing

[0091] Group 60° Glossiness Abrasion resistance test result Example 26 8.1 Only surface gloss change Example 27 6.5 Only surface gloss change Example 28 5.7 Only surface gloss change Example 29 4.3 Only surface gloss change Example 30 4.9 Only surface gloss change Example 31 6.3 Only surface gloss change Example 32 8.8 Only surface gloss change Example 33 7.2 Only surface gloss change Comparative Example 5 10.2 Severe wear

[0092] The excessive gloss of PVC artificial leather can affect the human eye and cause visual fatigue. After scraping and coating modified waterborne polyurethane on the surface, a modified waterborne polyurethane layer is formed. Glossiness is affected by the surface roughness of the material. Low roughness will cause light to shine and form a mirror surface, and reflection will result in high glossiness. Excessively low roughness causes the material surface to diffusely reflect, reflect, and scatter light, increasing the haze value of the PVC artificial leather surface and forming a turbid appearance. Excessive or too low surface roughness of the material is not conducive to the formation of good gloss on its surface.

[0093] The 60° glossiness of the super-durable PVC artificial leather obtained in the examples and comparative examples of the present invention is 4.3 - 10.2. Except for Comparative Example 5, after the PVC artificial leather of the examples undergoes wear resistance testing, only the surface gloss changes, and the wear resistance performance is good. In Examples 26 and 27, by selecting waterborne matting polyurethanes from different manufacturers, the glossiness changes, and different manufacturing processes of the same product affect the surface performance of PVC artificial leather. In Examples 28 - 32, by changing the dosages of fumed silica, nano-inorganic boron nitride, and curing agent, the material has good glossiness and wear resistance effect. Among them, the PVC artificial leather surfaces of Examples 29 and 30 reached the flat gloss level effect; in Example 32, the dosages of fumed silica and curing agent were reduced, the curing effect became worse, the roughness decreased, so the glossiness increased. Example 33 selected ordinary waterborne polyurethane and matting powder to prepare PVC artificial leather, and its surface also had good glossiness, and in addition, the wear resistance test was qualified. Comparative Example 5 did not add fumed silica and nano-inorganic boron nitride, the surface glossiness of the PVC artificial leather increased, and at the same time, the friction resistance performance was greatly reduced.

[0094] Example 35

[0095] Different from Example 1, the plant-derived fiber is chitosan fiber.

[0096] Example 36

[0097] Different from Example 1, the plant-derived fiber is lignin fiber.

[0098] Example 37

[0099] Different from Example 1, the plant-derived fiber is jute fiber.

[0100] Example 38

[0101] Different from Example 1, the plant-derived fiber and carbon fiber are in a parts ratio of 13:87.

[0102] Example 39

[0103] Different from Example 1, the plant-derived fiber and carbon fiber are in a parts ratio of 9:41.

[0104] Example 40

[0105] Different from Example 1, the parts ratio of sodium bicarbonate, coconut oil ethylene glycol amine, azodicarbonamide and toluene diisocyanate in the foaming agent is 4:1.5:9:7.

[0106] Example 41

[0107] Different from Example 1, the parts ratio of sodium bicarbonate, coconut oil ethylene glycol amine, azodicarbonamide and toluene diisocyanate in the foaming agent is 4:1.5:9:9.5.

[0108] Comparative Example 6

[0109] Different from Example 1, no plant-derived fiber is added.

[0110] Example 42

[0111] The super-durable PVC artificial leather prepared in Examples 35-41 and Comparative Example 6 was subjected to notched impact strength test and tensile strength test. By cutting the super-durable PVC artificial leather into dumbbell-shaped tensile test specimens, referring to the test method of ISO 180-2019, the notched impact strength was tested using an XJU-5.5 type impact tester; the test method for tensile strength was carried out with reference to the test method of Example 12. The test results are as Figure 2 shown.

[0112] Figure 2 The results show that the notched impact strength of the super-durable PVC artificial leather materials prepared in the examples and comparative examples is 52.5-67.4 J / m, and the tensile strength is 9.4-16.6 MPa. In Examples 35-37, the type of plant-derived fiber was changed, and the notched impact strength and tensile strength changed. As shown in Example 36, when lignin fiber and carbon fiber were used in combination, the notched impact strength of the prepared PVC artificial leather was the highest, at 64.0 J / m, but the tensile strength decreased compared with Examples 35 and 37. Compared with Example 1, in Examples 38 and 39, the amount of plant-derived fiber was increased, and the tensile strength showed a trend of decreasing first and then increasing. Compared with Example 1, in Example 40, the amount of toluene diisocyanate in the foaming agent was reduced, so the amount of polyurea structure compound formed during the foaming process was reduced, which was not conducive to increasing the mechanical properties of the PVC material; compared with Example 1, in Example 41, the amount of toluene diisocyanate was increased, and too much toluene diisocyanate led to a decrease in the tensile strength of the super-durable PVC foaming layer, and finally the tensile strength of the PVC artificial leather was 15.5 MPa. In Comparative Example 6, only carbon fiber was used as the base fabric raw material, and the notched impact strength reached the highest among the examples, at 67.4 J / m, but the tensile strength dropped to the lowest, at 9.4 MPa.

[0113] Examples 43-49

[0114] Different from Example 1, the preparation method of the PVC layer was changed, as specifically shown in Table 6.

[0115] Table 6 Condition changes during the preparation of the PVC layer

[0116]

[0117] Example 50

[0118] The super-durable PVC artificial leather prepared in Example 1, Examples 43-49, and Comparative Examples 7-9 was tested for high and low temperature resistance, aging resistance, and amine resistance. The specific test methods are as follows: The amine resistance of the super-durable PVC artificial leather was tested according to the Volkswagen PV3944 standard; according to the test conditions of the standard Q / JLY J7110279B—2014 "Automobile Interior and Exterior Non-Metallic Parts Light Aging Test Specification", the irradiance was 1.25 W / m 2 @420nm, the black standard temperature was 100 °C, the relative humidity was 52% RH, and the light exposure time was 330 h. The brittle fracture situation of the super-durable PVC artificial leather after aging was investigated; a HZXL-0112 type low-temperature resistance tester was used to measure the brittle fracture situation of the super-durable PVC artificial leather at -20 °C. The final test results were recorded in Table 7.

[0119] Table 7 Test results of high and low temperature resistance, aging resistance, and amine resistance of super-durable PVC artificial leather

[0120] Group Heat and aging resistance Low temperature resistance Amine resistance Example 1 No breakage after 100,000 times No breakage after 100,000 times No obvious color change, Da = 1.4 Example 43 No breakage after 100,000 times No breakage after 100,000 times No obvious color change, Da = 1.3 Example 44 No breakage after 100,000 times No breakage after 100,000 times No obvious color change, Da = 1.2 Example 45 No breakage after 100,000 times No breakage after 100,000 times No obvious color change, Da = 1.0 Example 46 No breakage after 100,000 times No breakage after 100,000 times No obvious color change, Da = 0.4 Example 47 No breakage after 80,000 times No breakage after 100,000 times No obvious color change, Da = 1.1 Example 48 No breakage after 80,000 times No breakage after 100,000 times No obvious color change, Da = 1.3 Example 49 No breakage after 100,000 times No breakage after 100,000 times No obvious color change, Da = 0.8 Comparative Example 7 No breakage after 40,000 times No breakage after 50,000 times No obvious color change, Da = 1.2 Comparative Example 8 No breakage after 80,000 times No breakage after 100,000 times Red color change, Da = 2.0 Comparative Example 9 No breakage after 100,000 times No breakage after 100,000 times Slight red color change, Da = 1.5

[0121] By reasonably adjusting the types and dosages of each component in the PVC layer, the super-durable PVC artificial leather prepared by the present invention did not crack after 40,000 - 100,000 times under the high temperature condition of 100 °C and ultraviolet irradiation; the PVC artificial leather did not crack after 50,000 - 100,000 times after the low temperature test; the amine resistance test results showed that except for the comparative examples, the PVC artificial leather of the examples did not show obvious color change, and the Da values of the examples and comparative examples were 0.4 - 2.0. In Examples 43-46, the types and ratios of substances in the stabilizer were changed. As shown in Example 46, when sodium perchlorate and methyl succinic anhydride were used at a fraction ratio of 4:1, the amine resistance was the best, and the Da value was only 0.4; while in Example 1, only sodium perchlorate was used as the stabilizer, and the amine resistance was lower than that of Examples 43-46. In Examples 47-49, the heat and aging resistance of Examples 47 and 48 did not crack after 80,000 times, and the performance decreased. In Comparative Example 7, the dosages of solution-polymerized styrene-butadiene rubber and plasticizer were reduced, and the high and low temperature resistance and aging resistance decreased. In Comparative Example 8, the dosage of the stabilizer was reduced, and in Comparative Example 9, only citric acid was used as the stabilizer, and the amine resistance effect of the PVC artificial leather decreased.

[0122] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Preparation method of super-durable PVC foam layer, characterized in that: It includes the following steps: Put castor oil and acid anhydride into a three-necked flask, react for 5 hours, and refine to obtain refined modified ricinoleic acid; Add polyol solution and styrene-butadiene to the refined modified ricinoleic acid to obtain a reaction solution; heat up the reaction solution and reflux to obtain a modified castor oil ester precursor; wash the modified castor oil ester precursor, separate the liquid, and distill under reduced pressure to obtain a modified castor oil ester; add formic acid and ethyl acetate to the modified castor oil ester, heat up, and dropwise add hydrogen peroxide solution to obtain a plasticizer reaction solution; stir and react the plasticizer reaction solution, then add KH550, continue to react for 6 h, wash with water for neutralization, and distill under reduced pressure to obtain plasticizer one; Vacuum stir PVC resin, plasticizer and 13 - 17 parts of foaming agent to obtain a mixture; the ratio of the number of parts of sodium bicarbonate, coconut oil ethylene glycol amine, azodicarbonamide and toluene diisocyanate in the foaming agent is 0 - 6:1.5 - 2:9 - 10:7 - 9.5; the plasticizer includes plasticizer one and plasticizer two; the ratio of the number of parts of plasticizer one and plasticizer two is 0 - 17:1 - 3; transfer the mixture to a sealed mold, vulcanize and cool, pop out and then put it into a constant temperature water tank and cure to obtain the super-durable PVC foaming layer; The acid anhydride is one of maleic anhydride, succinic anhydride, behenic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, dicyclooct-7-ene tetracarboxylic dianhydride, tricyclonon-8-ene dicarboxylic anhydride and (2,7-octadien-1-yl) succinic anhydride; The polyol is one of mesitylene triol and 1,4-butanediol; The PVC resin is one of SG-8, BY650 and SG-5; 2. The preparation method of the super-durable PVC foam layer according to claim 1, characterized in that: The plasticizer two is one of tributyl citrate and acetyl tributyl citrate; 3. The preparation method of the super-durable PVC foam layer according to claim 1, characterized in that: The ratio of the number of parts of sodium bicarbonate, coconut oil ethylene glycol amine, azodicarbonamide and toluene diisocyanate is 4 - 6:1.5 - 2:9 - 10:8; 4. The preparation method of the super-durable PVC foam layer according to claim 1, characterized in that: The ratio of the number of parts of plasticizer one and plasticizer two is 4 - 17:1 - 3; 5. Preparation method of super-durable PVC artificial leather, characterized in that: It includes the following steps: Mix vegetable fiber and carbon fiber according to the ratio of the number of parts 0 - 13:9 - 87 to obtain mixed fiber; Card the mixed fiber to prepare a membranous fiber web; reinforce the membranous fiber web to obtain a base cloth; Mix 94 - 108 parts of PVC resin, 5 - 18 parts of solution-polymerized styrene-butadiene rubber, 30 - 60 parts of plasticizer, 1 - 7 parts of stabilizer, 1.5 - 3 parts of antioxidant, processing heat stabilizer, 1 - 2 parts of ultraviolet absorber to obtain a mixture; the mixture is initially refined and refined to obtain a PVC slurry; the temperature of the initial refining and refining is 170 °C; the PVC slurry is calendered to obtain a PVC layer; Mix waterborne matte polyurethane, 0 - 3.5 parts of fumed silica, 0 - 4 parts of nano-inorganic boron nitride, leveling agent, nano-cellulose crystal, 0.3 - 0.6 parts of curing agent and defoaming agent to obtain a modified waterborne polyurethane precursor; Grind the modified waterborne polyurethane precursor to an average particle size of 30 - 60 μm to obtain a modified waterborne polyurethane; After laminating the super-durable PVC foam layer with the PVC layer, the modified waterborne polyurethane is scrape-coated on the surface of the PVC layer; The modified waterborne polyurethane is cured for 48 h to obtain a modified waterborne polyurethane layer; The modified waterborne polyurethane layer, the super-durable PVC foam layer, the PVC layer and the base fabric are laminated, surface-treated, embossed and cooled to obtain the super-durable PVC artificial leather.

6. The preparation method of the super-durable PVC artificial leather according to claim 5, characterized in that: The ratio of the plant-derived fiber to the carbon fiber is 1-13:9-87; the plant-derived fiber is one of calcium alginate fiber, chitosan fiber, lignin fiber and jute fiber.

7. The preparation method of the super-durable PVC artificial leather according to claim 5, characterized in that: The waterborne matte polyurethane is one of WR-8394A type and 549 type; the leveling agent is 540# leveling agent; the curing agent is DN curing agent; the defoaming agent is Cl-937; the processing heat stabilizer is organotin 181; the antioxidant is B900; the ultraviolet absorber is nano-titanium dioxide.

8. The preparation method of the super-durable PVC artificial leather according to claim 5, characterized in that: The amount of the fumed silica used is 1.5-3.5 parts; the amount of the nano-inorganic boron nitride used is 2-4 parts.

9. The preparation method of the super-durable PVC artificial leather according to claim 5, characterized in that: The amount of the PVC resin used is 94-100 parts; the amount of the solution-polymerized styrene-butadiene rubber used is 15-18 parts; the amount of the plasticizer used is 54-60 parts; the amount of the stabilizer used is 5-7 parts; the stabilizer is two of sodium perchlorate, citric acid, trifluoroacetic anhydride and methyl succinic anhydride.

10. Super-durable PVC foam layer, super-durable PVC artificial leather, characterized in that: The super-durable PVC foam layer comprises PVC resin, a plasticizer and a foaming agent; the super-durable PVC artificial leather comprises a base fabric, the PVC foam layer, a PVC layer and a modified waterborne polyurethane layer; the super-durable PVC foam layer is prepared by the preparation method described in any one of claims 1-4; the super-durable PVC artificial leather is prepared by the preparation method described in any one of claims 5-9; the super-durable PVC foam layer has a tensile strength of 9.2-13.2 MPa, an elongation at break of 375%-456%, and a glass transition temperature of 38-73 °C; the foaming density of the super-durable PVC foam layer is 0.17-0.43 g·cm -3 ; the 60° glossiness of the super-durable PVC artificial leather is 4.3-10.2, and only the surface gloss changes after wear resistance testing; the notched impact strength of the super-durable PVC artificial leather material is 52.5-67.4 J / m, and the tensile strength is 9.4-16.6 MPa; the super-durable PVC artificial leather does not rupture after 40,000-100,000 times under the conditions of 100 °C and ultraviolet irradiation; the PVC artificial leather does not rupture after 50,000-100,000 times after a low temperature test at -20 °C; the result of the amine resistance test shows no obvious color change, and the Da value is 0.4-1.4.

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